1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3 * Copyright (c) 2016 Facebook
4 * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
6 #include <uapi/linux/btf.h>
7 #include <linux/bpf-cgroup.h>
8 #include <linux/kernel.h>
9 #include <linux/types.h>
10 #include <linux/slab.h>
11 #include <linux/bpf.h>
12 #include <linux/btf.h>
13 #include <linux/bpf_verifier.h>
14 #include <linux/filter.h>
15 #include <net/netlink.h>
16 #include <linux/file.h>
17 #include <linux/vmalloc.h>
18 #include <linux/stringify.h>
19 #include <linux/bsearch.h>
20 #include <linux/sort.h>
21 #include <linux/perf_event.h>
22 #include <linux/ctype.h>
23 #include <linux/error-injection.h>
24 #include <linux/bpf_lsm.h>
25 #include <linux/btf_ids.h>
26 #include <linux/poison.h>
27 #include <linux/module.h>
28 #include <linux/cpumask.h>
33 static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
34 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
35 [_id] = & _name ## _verifier_ops,
36 #define BPF_MAP_TYPE(_id, _ops)
37 #define BPF_LINK_TYPE(_id, _name)
38 #include <linux/bpf_types.h>
44 /* bpf_check() is a static code analyzer that walks eBPF program
45 * instruction by instruction and updates register/stack state.
46 * All paths of conditional branches are analyzed until 'bpf_exit' insn.
48 * The first pass is depth-first-search to check that the program is a DAG.
49 * It rejects the following programs:
50 * - larger than BPF_MAXINSNS insns
51 * - if loop is present (detected via back-edge)
52 * - unreachable insns exist (shouldn't be a forest. program = one function)
53 * - out of bounds or malformed jumps
54 * The second pass is all possible path descent from the 1st insn.
55 * Since it's analyzing all paths through the program, the length of the
56 * analysis is limited to 64k insn, which may be hit even if total number of
57 * insn is less then 4K, but there are too many branches that change stack/regs.
58 * Number of 'branches to be analyzed' is limited to 1k
60 * On entry to each instruction, each register has a type, and the instruction
61 * changes the types of the registers depending on instruction semantics.
62 * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
65 * All registers are 64-bit.
66 * R0 - return register
67 * R1-R5 argument passing registers
68 * R6-R9 callee saved registers
69 * R10 - frame pointer read-only
71 * At the start of BPF program the register R1 contains a pointer to bpf_context
72 * and has type PTR_TO_CTX.
74 * Verifier tracks arithmetic operations on pointers in case:
75 * BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
76 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
77 * 1st insn copies R10 (which has FRAME_PTR) type into R1
78 * and 2nd arithmetic instruction is pattern matched to recognize
79 * that it wants to construct a pointer to some element within stack.
80 * So after 2nd insn, the register R1 has type PTR_TO_STACK
81 * (and -20 constant is saved for further stack bounds checking).
82 * Meaning that this reg is a pointer to stack plus known immediate constant.
84 * Most of the time the registers have SCALAR_VALUE type, which
85 * means the register has some value, but it's not a valid pointer.
86 * (like pointer plus pointer becomes SCALAR_VALUE type)
88 * When verifier sees load or store instructions the type of base register
89 * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
90 * four pointer types recognized by check_mem_access() function.
92 * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
93 * and the range of [ptr, ptr + map's value_size) is accessible.
95 * registers used to pass values to function calls are checked against
96 * function argument constraints.
98 * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
99 * It means that the register type passed to this function must be
100 * PTR_TO_STACK and it will be used inside the function as
101 * 'pointer to map element key'
103 * For example the argument constraints for bpf_map_lookup_elem():
104 * .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
105 * .arg1_type = ARG_CONST_MAP_PTR,
106 * .arg2_type = ARG_PTR_TO_MAP_KEY,
108 * ret_type says that this function returns 'pointer to map elem value or null'
109 * function expects 1st argument to be a const pointer to 'struct bpf_map' and
110 * 2nd argument should be a pointer to stack, which will be used inside
111 * the helper function as a pointer to map element key.
113 * On the kernel side the helper function looks like:
114 * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
116 * struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
117 * void *key = (void *) (unsigned long) r2;
120 * here kernel can access 'key' and 'map' pointers safely, knowing that
121 * [key, key + map->key_size) bytes are valid and were initialized on
122 * the stack of eBPF program.
125 * Corresponding eBPF program may look like:
126 * BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), // after this insn R2 type is FRAME_PTR
127 * BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
128 * BPF_LD_MAP_FD(BPF_REG_1, map_fd), // after this insn R1 type is CONST_PTR_TO_MAP
129 * BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
130 * here verifier looks at prototype of map_lookup_elem() and sees:
131 * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
132 * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
134 * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
135 * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
136 * and were initialized prior to this call.
137 * If it's ok, then verifier allows this BPF_CALL insn and looks at
138 * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
139 * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
140 * returns either pointer to map value or NULL.
142 * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
143 * insn, the register holding that pointer in the true branch changes state to
144 * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
145 * branch. See check_cond_jmp_op().
147 * After the call R0 is set to return type of the function and registers R1-R5
148 * are set to NOT_INIT to indicate that they are no longer readable.
150 * The following reference types represent a potential reference to a kernel
151 * resource which, after first being allocated, must be checked and freed by
153 * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
155 * When the verifier sees a helper call return a reference type, it allocates a
156 * pointer id for the reference and stores it in the current function state.
157 * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
158 * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
159 * passes through a NULL-check conditional. For the branch wherein the state is
160 * changed to CONST_IMM, the verifier releases the reference.
162 * For each helper function that allocates a reference, such as
163 * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
164 * bpf_sk_release(). When a reference type passes into the release function,
165 * the verifier also releases the reference. If any unchecked or unreleased
166 * reference remains at the end of the program, the verifier rejects it.
169 /* verifier_state + insn_idx are pushed to stack when branch is encountered */
170 struct bpf_verifier_stack_elem {
171 /* verifer state is 'st'
172 * before processing instruction 'insn_idx'
173 * and after processing instruction 'prev_insn_idx'
175 struct bpf_verifier_state st;
178 struct bpf_verifier_stack_elem *next;
179 /* length of verifier log at the time this state was pushed on stack */
183 #define BPF_COMPLEXITY_LIMIT_JMP_SEQ 8192
184 #define BPF_COMPLEXITY_LIMIT_STATES 64
186 #define BPF_MAP_KEY_POISON (1ULL << 63)
187 #define BPF_MAP_KEY_SEEN (1ULL << 62)
189 #define BPF_MAP_PTR_UNPRIV 1UL
190 #define BPF_MAP_PTR_POISON ((void *)((0xeB9FUL << 1) + \
191 POISON_POINTER_DELTA))
192 #define BPF_MAP_PTR(X) ((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
194 static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx);
195 static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
196 static void invalidate_non_owning_refs(struct bpf_verifier_env *env);
197 static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env);
198 static int ref_set_non_owning(struct bpf_verifier_env *env,
199 struct bpf_reg_state *reg);
200 static void specialize_kfunc(struct bpf_verifier_env *env,
201 u32 func_id, u16 offset, unsigned long *addr);
202 static bool is_trusted_reg(const struct bpf_reg_state *reg);
204 static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
206 return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON;
209 static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
211 return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
214 static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
215 const struct bpf_map *map, bool unpriv)
217 BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
218 unpriv |= bpf_map_ptr_unpriv(aux);
219 aux->map_ptr_state = (unsigned long)map |
220 (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
223 static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
225 return aux->map_key_state & BPF_MAP_KEY_POISON;
228 static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
230 return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
233 static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
235 return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
238 static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
240 bool poisoned = bpf_map_key_poisoned(aux);
242 aux->map_key_state = state | BPF_MAP_KEY_SEEN |
243 (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
246 static bool bpf_helper_call(const struct bpf_insn *insn)
248 return insn->code == (BPF_JMP | BPF_CALL) &&
252 static bool bpf_pseudo_call(const struct bpf_insn *insn)
254 return insn->code == (BPF_JMP | BPF_CALL) &&
255 insn->src_reg == BPF_PSEUDO_CALL;
258 static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn)
260 return insn->code == (BPF_JMP | BPF_CALL) &&
261 insn->src_reg == BPF_PSEUDO_KFUNC_CALL;
264 struct bpf_call_arg_meta {
265 struct bpf_map *map_ptr;
282 struct btf_field *kptr_field;
285 struct bpf_kfunc_call_arg_meta {
290 const struct btf_type *func_proto;
291 const char *func_name;
304 /* arg_{btf,btf_id,owning_ref} are used by kfunc-specific handling,
305 * generally to pass info about user-defined local kptr types to later
308 * Record the local kptr type to be drop'd
309 * bpf_refcount_acquire (via KF_ARG_PTR_TO_REFCOUNTED_KPTR arg type)
310 * Record the local kptr type to be refcount_incr'd and use
311 * arg_owning_ref to determine whether refcount_acquire should be
319 struct btf_field *field;
322 struct btf_field *field;
325 enum bpf_dynptr_type type;
328 } initialized_dynptr;
336 struct btf *btf_vmlinux;
338 static DEFINE_MUTEX(bpf_verifier_lock);
340 static const struct bpf_line_info *
341 find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
343 const struct bpf_line_info *linfo;
344 const struct bpf_prog *prog;
348 nr_linfo = prog->aux->nr_linfo;
350 if (!nr_linfo || insn_off >= prog->len)
353 linfo = prog->aux->linfo;
354 for (i = 1; i < nr_linfo; i++)
355 if (insn_off < linfo[i].insn_off)
358 return &linfo[i - 1];
361 __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
363 struct bpf_verifier_env *env = private_data;
366 if (!bpf_verifier_log_needed(&env->log))
370 bpf_verifier_vlog(&env->log, fmt, args);
374 static const char *ltrim(const char *s)
382 __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
384 const char *prefix_fmt, ...)
386 const struct bpf_line_info *linfo;
388 if (!bpf_verifier_log_needed(&env->log))
391 linfo = find_linfo(env, insn_off);
392 if (!linfo || linfo == env->prev_linfo)
398 va_start(args, prefix_fmt);
399 bpf_verifier_vlog(&env->log, prefix_fmt, args);
404 ltrim(btf_name_by_offset(env->prog->aux->btf,
407 env->prev_linfo = linfo;
410 static void verbose_invalid_scalar(struct bpf_verifier_env *env,
411 struct bpf_reg_state *reg,
412 struct tnum *range, const char *ctx,
413 const char *reg_name)
417 verbose(env, "At %s the register %s ", ctx, reg_name);
418 if (!tnum_is_unknown(reg->var_off)) {
419 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
420 verbose(env, "has value %s", tn_buf);
422 verbose(env, "has unknown scalar value");
424 tnum_strn(tn_buf, sizeof(tn_buf), *range);
425 verbose(env, " should have been in %s\n", tn_buf);
428 static bool type_is_pkt_pointer(enum bpf_reg_type type)
430 type = base_type(type);
431 return type == PTR_TO_PACKET ||
432 type == PTR_TO_PACKET_META;
435 static bool type_is_sk_pointer(enum bpf_reg_type type)
437 return type == PTR_TO_SOCKET ||
438 type == PTR_TO_SOCK_COMMON ||
439 type == PTR_TO_TCP_SOCK ||
440 type == PTR_TO_XDP_SOCK;
443 static bool type_may_be_null(u32 type)
445 return type & PTR_MAYBE_NULL;
448 static bool reg_not_null(const struct bpf_reg_state *reg)
450 enum bpf_reg_type type;
453 if (type_may_be_null(type))
456 type = base_type(type);
457 return type == PTR_TO_SOCKET ||
458 type == PTR_TO_TCP_SOCK ||
459 type == PTR_TO_MAP_VALUE ||
460 type == PTR_TO_MAP_KEY ||
461 type == PTR_TO_SOCK_COMMON ||
462 (type == PTR_TO_BTF_ID && is_trusted_reg(reg)) ||
466 static bool type_is_ptr_alloc_obj(u32 type)
468 return base_type(type) == PTR_TO_BTF_ID && type_flag(type) & MEM_ALLOC;
471 static bool type_is_non_owning_ref(u32 type)
473 return type_is_ptr_alloc_obj(type) && type_flag(type) & NON_OWN_REF;
476 static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg)
478 struct btf_record *rec = NULL;
479 struct btf_struct_meta *meta;
481 if (reg->type == PTR_TO_MAP_VALUE) {
482 rec = reg->map_ptr->record;
483 } else if (type_is_ptr_alloc_obj(reg->type)) {
484 meta = btf_find_struct_meta(reg->btf, reg->btf_id);
491 static bool subprog_is_global(const struct bpf_verifier_env *env, int subprog)
493 struct bpf_func_info_aux *aux = env->prog->aux->func_info_aux;
495 return aux && aux[subprog].linkage == BTF_FUNC_GLOBAL;
498 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
500 return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK);
503 static bool type_is_rdonly_mem(u32 type)
505 return type & MEM_RDONLY;
508 static bool is_acquire_function(enum bpf_func_id func_id,
509 const struct bpf_map *map)
511 enum bpf_map_type map_type = map ? map->map_type : BPF_MAP_TYPE_UNSPEC;
513 if (func_id == BPF_FUNC_sk_lookup_tcp ||
514 func_id == BPF_FUNC_sk_lookup_udp ||
515 func_id == BPF_FUNC_skc_lookup_tcp ||
516 func_id == BPF_FUNC_ringbuf_reserve ||
517 func_id == BPF_FUNC_kptr_xchg)
520 if (func_id == BPF_FUNC_map_lookup_elem &&
521 (map_type == BPF_MAP_TYPE_SOCKMAP ||
522 map_type == BPF_MAP_TYPE_SOCKHASH))
528 static bool is_ptr_cast_function(enum bpf_func_id func_id)
530 return func_id == BPF_FUNC_tcp_sock ||
531 func_id == BPF_FUNC_sk_fullsock ||
532 func_id == BPF_FUNC_skc_to_tcp_sock ||
533 func_id == BPF_FUNC_skc_to_tcp6_sock ||
534 func_id == BPF_FUNC_skc_to_udp6_sock ||
535 func_id == BPF_FUNC_skc_to_mptcp_sock ||
536 func_id == BPF_FUNC_skc_to_tcp_timewait_sock ||
537 func_id == BPF_FUNC_skc_to_tcp_request_sock;
540 static bool is_dynptr_ref_function(enum bpf_func_id func_id)
542 return func_id == BPF_FUNC_dynptr_data;
545 static bool is_callback_calling_kfunc(u32 btf_id);
547 static bool is_callback_calling_function(enum bpf_func_id func_id)
549 return func_id == BPF_FUNC_for_each_map_elem ||
550 func_id == BPF_FUNC_timer_set_callback ||
551 func_id == BPF_FUNC_find_vma ||
552 func_id == BPF_FUNC_loop ||
553 func_id == BPF_FUNC_user_ringbuf_drain;
556 static bool is_async_callback_calling_function(enum bpf_func_id func_id)
558 return func_id == BPF_FUNC_timer_set_callback;
561 static bool is_storage_get_function(enum bpf_func_id func_id)
563 return func_id == BPF_FUNC_sk_storage_get ||
564 func_id == BPF_FUNC_inode_storage_get ||
565 func_id == BPF_FUNC_task_storage_get ||
566 func_id == BPF_FUNC_cgrp_storage_get;
569 static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id,
570 const struct bpf_map *map)
572 int ref_obj_uses = 0;
574 if (is_ptr_cast_function(func_id))
576 if (is_acquire_function(func_id, map))
578 if (is_dynptr_ref_function(func_id))
581 return ref_obj_uses > 1;
584 static bool is_cmpxchg_insn(const struct bpf_insn *insn)
586 return BPF_CLASS(insn->code) == BPF_STX &&
587 BPF_MODE(insn->code) == BPF_ATOMIC &&
588 insn->imm == BPF_CMPXCHG;
591 /* string representation of 'enum bpf_reg_type'
593 * Note that reg_type_str() can not appear more than once in a single verbose()
596 static const char *reg_type_str(struct bpf_verifier_env *env,
597 enum bpf_reg_type type)
599 char postfix[16] = {0}, prefix[64] = {0};
600 static const char * const str[] = {
602 [SCALAR_VALUE] = "scalar",
603 [PTR_TO_CTX] = "ctx",
604 [CONST_PTR_TO_MAP] = "map_ptr",
605 [PTR_TO_MAP_VALUE] = "map_value",
606 [PTR_TO_STACK] = "fp",
607 [PTR_TO_PACKET] = "pkt",
608 [PTR_TO_PACKET_META] = "pkt_meta",
609 [PTR_TO_PACKET_END] = "pkt_end",
610 [PTR_TO_FLOW_KEYS] = "flow_keys",
611 [PTR_TO_SOCKET] = "sock",
612 [PTR_TO_SOCK_COMMON] = "sock_common",
613 [PTR_TO_TCP_SOCK] = "tcp_sock",
614 [PTR_TO_TP_BUFFER] = "tp_buffer",
615 [PTR_TO_XDP_SOCK] = "xdp_sock",
616 [PTR_TO_BTF_ID] = "ptr_",
617 [PTR_TO_MEM] = "mem",
618 [PTR_TO_BUF] = "buf",
619 [PTR_TO_FUNC] = "func",
620 [PTR_TO_MAP_KEY] = "map_key",
621 [CONST_PTR_TO_DYNPTR] = "dynptr_ptr",
624 if (type & PTR_MAYBE_NULL) {
625 if (base_type(type) == PTR_TO_BTF_ID)
626 strncpy(postfix, "or_null_", 16);
628 strncpy(postfix, "_or_null", 16);
631 snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s%s",
632 type & MEM_RDONLY ? "rdonly_" : "",
633 type & MEM_RINGBUF ? "ringbuf_" : "",
634 type & MEM_USER ? "user_" : "",
635 type & MEM_PERCPU ? "percpu_" : "",
636 type & MEM_RCU ? "rcu_" : "",
637 type & PTR_UNTRUSTED ? "untrusted_" : "",
638 type & PTR_TRUSTED ? "trusted_" : ""
641 snprintf(env->tmp_str_buf, TMP_STR_BUF_LEN, "%s%s%s",
642 prefix, str[base_type(type)], postfix);
643 return env->tmp_str_buf;
646 static char slot_type_char[] = {
647 [STACK_INVALID] = '?',
651 [STACK_DYNPTR] = 'd',
655 static void print_liveness(struct bpf_verifier_env *env,
656 enum bpf_reg_liveness live)
658 if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
660 if (live & REG_LIVE_READ)
662 if (live & REG_LIVE_WRITTEN)
664 if (live & REG_LIVE_DONE)
668 static int __get_spi(s32 off)
670 return (-off - 1) / BPF_REG_SIZE;
673 static struct bpf_func_state *func(struct bpf_verifier_env *env,
674 const struct bpf_reg_state *reg)
676 struct bpf_verifier_state *cur = env->cur_state;
678 return cur->frame[reg->frameno];
681 static bool is_spi_bounds_valid(struct bpf_func_state *state, int spi, int nr_slots)
683 int allocated_slots = state->allocated_stack / BPF_REG_SIZE;
685 /* We need to check that slots between [spi - nr_slots + 1, spi] are
686 * within [0, allocated_stack).
688 * Please note that the spi grows downwards. For example, a dynptr
689 * takes the size of two stack slots; the first slot will be at
690 * spi and the second slot will be at spi - 1.
692 return spi - nr_slots + 1 >= 0 && spi < allocated_slots;
695 static int stack_slot_obj_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
696 const char *obj_kind, int nr_slots)
700 if (!tnum_is_const(reg->var_off)) {
701 verbose(env, "%s has to be at a constant offset\n", obj_kind);
705 off = reg->off + reg->var_off.value;
706 if (off % BPF_REG_SIZE) {
707 verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
711 spi = __get_spi(off);
712 if (spi + 1 < nr_slots) {
713 verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
717 if (!is_spi_bounds_valid(func(env, reg), spi, nr_slots))
722 static int dynptr_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
724 return stack_slot_obj_get_spi(env, reg, "dynptr", BPF_DYNPTR_NR_SLOTS);
727 static int iter_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int nr_slots)
729 return stack_slot_obj_get_spi(env, reg, "iter", nr_slots);
732 static const char *btf_type_name(const struct btf *btf, u32 id)
734 return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
737 static const char *dynptr_type_str(enum bpf_dynptr_type type)
740 case BPF_DYNPTR_TYPE_LOCAL:
742 case BPF_DYNPTR_TYPE_RINGBUF:
744 case BPF_DYNPTR_TYPE_SKB:
746 case BPF_DYNPTR_TYPE_XDP:
748 case BPF_DYNPTR_TYPE_INVALID:
751 WARN_ONCE(1, "unknown dynptr type %d\n", type);
756 static const char *iter_type_str(const struct btf *btf, u32 btf_id)
758 if (!btf || btf_id == 0)
761 /* we already validated that type is valid and has conforming name */
762 return btf_type_name(btf, btf_id) + sizeof(ITER_PREFIX) - 1;
765 static const char *iter_state_str(enum bpf_iter_state state)
768 case BPF_ITER_STATE_ACTIVE:
770 case BPF_ITER_STATE_DRAINED:
772 case BPF_ITER_STATE_INVALID:
775 WARN_ONCE(1, "unknown iter state %d\n", state);
780 static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)
782 env->scratched_regs |= 1U << regno;
785 static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)
787 env->scratched_stack_slots |= 1ULL << spi;
790 static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)
792 return (env->scratched_regs >> regno) & 1;
795 static bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno)
797 return (env->scratched_stack_slots >> regno) & 1;
800 static bool verifier_state_scratched(const struct bpf_verifier_env *env)
802 return env->scratched_regs || env->scratched_stack_slots;
805 static void mark_verifier_state_clean(struct bpf_verifier_env *env)
807 env->scratched_regs = 0U;
808 env->scratched_stack_slots = 0ULL;
811 /* Used for printing the entire verifier state. */
812 static void mark_verifier_state_scratched(struct bpf_verifier_env *env)
814 env->scratched_regs = ~0U;
815 env->scratched_stack_slots = ~0ULL;
818 static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type)
820 switch (arg_type & DYNPTR_TYPE_FLAG_MASK) {
821 case DYNPTR_TYPE_LOCAL:
822 return BPF_DYNPTR_TYPE_LOCAL;
823 case DYNPTR_TYPE_RINGBUF:
824 return BPF_DYNPTR_TYPE_RINGBUF;
825 case DYNPTR_TYPE_SKB:
826 return BPF_DYNPTR_TYPE_SKB;
827 case DYNPTR_TYPE_XDP:
828 return BPF_DYNPTR_TYPE_XDP;
830 return BPF_DYNPTR_TYPE_INVALID;
834 static enum bpf_type_flag get_dynptr_type_flag(enum bpf_dynptr_type type)
837 case BPF_DYNPTR_TYPE_LOCAL:
838 return DYNPTR_TYPE_LOCAL;
839 case BPF_DYNPTR_TYPE_RINGBUF:
840 return DYNPTR_TYPE_RINGBUF;
841 case BPF_DYNPTR_TYPE_SKB:
842 return DYNPTR_TYPE_SKB;
843 case BPF_DYNPTR_TYPE_XDP:
844 return DYNPTR_TYPE_XDP;
850 static bool dynptr_type_refcounted(enum bpf_dynptr_type type)
852 return type == BPF_DYNPTR_TYPE_RINGBUF;
855 static void __mark_dynptr_reg(struct bpf_reg_state *reg,
856 enum bpf_dynptr_type type,
857 bool first_slot, int dynptr_id);
859 static void __mark_reg_not_init(const struct bpf_verifier_env *env,
860 struct bpf_reg_state *reg);
862 static void mark_dynptr_stack_regs(struct bpf_verifier_env *env,
863 struct bpf_reg_state *sreg1,
864 struct bpf_reg_state *sreg2,
865 enum bpf_dynptr_type type)
867 int id = ++env->id_gen;
869 __mark_dynptr_reg(sreg1, type, true, id);
870 __mark_dynptr_reg(sreg2, type, false, id);
873 static void mark_dynptr_cb_reg(struct bpf_verifier_env *env,
874 struct bpf_reg_state *reg,
875 enum bpf_dynptr_type type)
877 __mark_dynptr_reg(reg, type, true, ++env->id_gen);
880 static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
881 struct bpf_func_state *state, int spi);
883 static int mark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
884 enum bpf_arg_type arg_type, int insn_idx, int clone_ref_obj_id)
886 struct bpf_func_state *state = func(env, reg);
887 enum bpf_dynptr_type type;
890 spi = dynptr_get_spi(env, reg);
894 /* We cannot assume both spi and spi - 1 belong to the same dynptr,
895 * hence we need to call destroy_if_dynptr_stack_slot twice for both,
896 * to ensure that for the following example:
899 * So marking spi = 2 should lead to destruction of both d1 and d2. In
900 * case they do belong to same dynptr, second call won't see slot_type
901 * as STACK_DYNPTR and will simply skip destruction.
903 err = destroy_if_dynptr_stack_slot(env, state, spi);
906 err = destroy_if_dynptr_stack_slot(env, state, spi - 1);
910 for (i = 0; i < BPF_REG_SIZE; i++) {
911 state->stack[spi].slot_type[i] = STACK_DYNPTR;
912 state->stack[spi - 1].slot_type[i] = STACK_DYNPTR;
915 type = arg_to_dynptr_type(arg_type);
916 if (type == BPF_DYNPTR_TYPE_INVALID)
919 mark_dynptr_stack_regs(env, &state->stack[spi].spilled_ptr,
920 &state->stack[spi - 1].spilled_ptr, type);
922 if (dynptr_type_refcounted(type)) {
923 /* The id is used to track proper releasing */
926 if (clone_ref_obj_id)
927 id = clone_ref_obj_id;
929 id = acquire_reference_state(env, insn_idx);
934 state->stack[spi].spilled_ptr.ref_obj_id = id;
935 state->stack[spi - 1].spilled_ptr.ref_obj_id = id;
938 state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
939 state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
944 static void invalidate_dynptr(struct bpf_verifier_env *env, struct bpf_func_state *state, int spi)
948 for (i = 0; i < BPF_REG_SIZE; i++) {
949 state->stack[spi].slot_type[i] = STACK_INVALID;
950 state->stack[spi - 1].slot_type[i] = STACK_INVALID;
953 __mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
954 __mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
956 /* Why do we need to set REG_LIVE_WRITTEN for STACK_INVALID slot?
958 * While we don't allow reading STACK_INVALID, it is still possible to
959 * do <8 byte writes marking some but not all slots as STACK_MISC. Then,
960 * helpers or insns can do partial read of that part without failing,
961 * but check_stack_range_initialized, check_stack_read_var_off, and
962 * check_stack_read_fixed_off will do mark_reg_read for all 8-bytes of
963 * the slot conservatively. Hence we need to prevent those liveness
966 * This was not a problem before because STACK_INVALID is only set by
967 * default (where the default reg state has its reg->parent as NULL), or
968 * in clean_live_states after REG_LIVE_DONE (at which point
969 * mark_reg_read won't walk reg->parent chain), but not randomly during
970 * verifier state exploration (like we did above). Hence, for our case
971 * parentage chain will still be live (i.e. reg->parent may be
972 * non-NULL), while earlier reg->parent was NULL, so we need
973 * REG_LIVE_WRITTEN to screen off read marker propagation when it is
974 * done later on reads or by mark_dynptr_read as well to unnecessary
975 * mark registers in verifier state.
977 state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
978 state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
981 static int unmark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
983 struct bpf_func_state *state = func(env, reg);
984 int spi, ref_obj_id, i;
986 spi = dynptr_get_spi(env, reg);
990 if (!dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
991 invalidate_dynptr(env, state, spi);
995 ref_obj_id = state->stack[spi].spilled_ptr.ref_obj_id;
997 /* If the dynptr has a ref_obj_id, then we need to invalidate
1000 * 1) Any dynptrs with a matching ref_obj_id (clones)
1001 * 2) Any slices derived from this dynptr.
1004 /* Invalidate any slices associated with this dynptr */
1005 WARN_ON_ONCE(release_reference(env, ref_obj_id));
1007 /* Invalidate any dynptr clones */
1008 for (i = 1; i < state->allocated_stack / BPF_REG_SIZE; i++) {
1009 if (state->stack[i].spilled_ptr.ref_obj_id != ref_obj_id)
1012 /* it should always be the case that if the ref obj id
1013 * matches then the stack slot also belongs to a
1016 if (state->stack[i].slot_type[0] != STACK_DYNPTR) {
1017 verbose(env, "verifier internal error: misconfigured ref_obj_id\n");
1020 if (state->stack[i].spilled_ptr.dynptr.first_slot)
1021 invalidate_dynptr(env, state, i);
1027 static void __mark_reg_unknown(const struct bpf_verifier_env *env,
1028 struct bpf_reg_state *reg);
1030 static void mark_reg_invalid(const struct bpf_verifier_env *env, struct bpf_reg_state *reg)
1032 if (!env->allow_ptr_leaks)
1033 __mark_reg_not_init(env, reg);
1035 __mark_reg_unknown(env, reg);
1038 static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
1039 struct bpf_func_state *state, int spi)
1041 struct bpf_func_state *fstate;
1042 struct bpf_reg_state *dreg;
1045 /* We always ensure that STACK_DYNPTR is never set partially,
1046 * hence just checking for slot_type[0] is enough. This is
1047 * different for STACK_SPILL, where it may be only set for
1048 * 1 byte, so code has to use is_spilled_reg.
1050 if (state->stack[spi].slot_type[0] != STACK_DYNPTR)
1053 /* Reposition spi to first slot */
1054 if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
1057 if (dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
1058 verbose(env, "cannot overwrite referenced dynptr\n");
1062 mark_stack_slot_scratched(env, spi);
1063 mark_stack_slot_scratched(env, spi - 1);
1065 /* Writing partially to one dynptr stack slot destroys both. */
1066 for (i = 0; i < BPF_REG_SIZE; i++) {
1067 state->stack[spi].slot_type[i] = STACK_INVALID;
1068 state->stack[spi - 1].slot_type[i] = STACK_INVALID;
1071 dynptr_id = state->stack[spi].spilled_ptr.id;
1072 /* Invalidate any slices associated with this dynptr */
1073 bpf_for_each_reg_in_vstate(env->cur_state, fstate, dreg, ({
1074 /* Dynptr slices are only PTR_TO_MEM_OR_NULL and PTR_TO_MEM */
1075 if (dreg->type != (PTR_TO_MEM | PTR_MAYBE_NULL) && dreg->type != PTR_TO_MEM)
1077 if (dreg->dynptr_id == dynptr_id)
1078 mark_reg_invalid(env, dreg);
1081 /* Do not release reference state, we are destroying dynptr on stack,
1082 * not using some helper to release it. Just reset register.
1084 __mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
1085 __mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
1087 /* Same reason as unmark_stack_slots_dynptr above */
1088 state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
1089 state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
1094 static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
1098 if (reg->type == CONST_PTR_TO_DYNPTR)
1101 spi = dynptr_get_spi(env, reg);
1103 /* -ERANGE (i.e. spi not falling into allocated stack slots) isn't an
1104 * error because this just means the stack state hasn't been updated yet.
1105 * We will do check_mem_access to check and update stack bounds later.
1107 if (spi < 0 && spi != -ERANGE)
1110 /* We don't need to check if the stack slots are marked by previous
1111 * dynptr initializations because we allow overwriting existing unreferenced
1112 * STACK_DYNPTR slots, see mark_stack_slots_dynptr which calls
1113 * destroy_if_dynptr_stack_slot to ensure dynptr objects at the slots we are
1114 * touching are completely destructed before we reinitialize them for a new
1115 * one. For referenced ones, destroy_if_dynptr_stack_slot returns an error early
1116 * instead of delaying it until the end where the user will get "Unreleased
1122 static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
1124 struct bpf_func_state *state = func(env, reg);
1127 /* This already represents first slot of initialized bpf_dynptr.
1129 * CONST_PTR_TO_DYNPTR already has fixed and var_off as 0 due to
1130 * check_func_arg_reg_off's logic, so we don't need to check its
1131 * offset and alignment.
1133 if (reg->type == CONST_PTR_TO_DYNPTR)
1136 spi = dynptr_get_spi(env, reg);
1139 if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
1142 for (i = 0; i < BPF_REG_SIZE; i++) {
1143 if (state->stack[spi].slot_type[i] != STACK_DYNPTR ||
1144 state->stack[spi - 1].slot_type[i] != STACK_DYNPTR)
1151 static bool is_dynptr_type_expected(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
1152 enum bpf_arg_type arg_type)
1154 struct bpf_func_state *state = func(env, reg);
1155 enum bpf_dynptr_type dynptr_type;
1158 /* ARG_PTR_TO_DYNPTR takes any type of dynptr */
1159 if (arg_type == ARG_PTR_TO_DYNPTR)
1162 dynptr_type = arg_to_dynptr_type(arg_type);
1163 if (reg->type == CONST_PTR_TO_DYNPTR) {
1164 return reg->dynptr.type == dynptr_type;
1166 spi = dynptr_get_spi(env, reg);
1169 return state->stack[spi].spilled_ptr.dynptr.type == dynptr_type;
1173 static void __mark_reg_known_zero(struct bpf_reg_state *reg);
1175 static int mark_stack_slots_iter(struct bpf_verifier_env *env,
1176 struct bpf_reg_state *reg, int insn_idx,
1177 struct btf *btf, u32 btf_id, int nr_slots)
1179 struct bpf_func_state *state = func(env, reg);
1182 spi = iter_get_spi(env, reg, nr_slots);
1186 id = acquire_reference_state(env, insn_idx);
1190 for (i = 0; i < nr_slots; i++) {
1191 struct bpf_stack_state *slot = &state->stack[spi - i];
1192 struct bpf_reg_state *st = &slot->spilled_ptr;
1194 __mark_reg_known_zero(st);
1195 st->type = PTR_TO_STACK; /* we don't have dedicated reg type */
1196 st->live |= REG_LIVE_WRITTEN;
1197 st->ref_obj_id = i == 0 ? id : 0;
1199 st->iter.btf_id = btf_id;
1200 st->iter.state = BPF_ITER_STATE_ACTIVE;
1203 for (j = 0; j < BPF_REG_SIZE; j++)
1204 slot->slot_type[j] = STACK_ITER;
1206 mark_stack_slot_scratched(env, spi - i);
1212 static int unmark_stack_slots_iter(struct bpf_verifier_env *env,
1213 struct bpf_reg_state *reg, int nr_slots)
1215 struct bpf_func_state *state = func(env, reg);
1218 spi = iter_get_spi(env, reg, nr_slots);
1222 for (i = 0; i < nr_slots; i++) {
1223 struct bpf_stack_state *slot = &state->stack[spi - i];
1224 struct bpf_reg_state *st = &slot->spilled_ptr;
1227 WARN_ON_ONCE(release_reference(env, st->ref_obj_id));
1229 __mark_reg_not_init(env, st);
1231 /* see unmark_stack_slots_dynptr() for why we need to set REG_LIVE_WRITTEN */
1232 st->live |= REG_LIVE_WRITTEN;
1234 for (j = 0; j < BPF_REG_SIZE; j++)
1235 slot->slot_type[j] = STACK_INVALID;
1237 mark_stack_slot_scratched(env, spi - i);
1243 static bool is_iter_reg_valid_uninit(struct bpf_verifier_env *env,
1244 struct bpf_reg_state *reg, int nr_slots)
1246 struct bpf_func_state *state = func(env, reg);
1249 /* For -ERANGE (i.e. spi not falling into allocated stack slots), we
1250 * will do check_mem_access to check and update stack bounds later, so
1251 * return true for that case.
1253 spi = iter_get_spi(env, reg, nr_slots);
1259 for (i = 0; i < nr_slots; i++) {
1260 struct bpf_stack_state *slot = &state->stack[spi - i];
1262 for (j = 0; j < BPF_REG_SIZE; j++)
1263 if (slot->slot_type[j] == STACK_ITER)
1270 static bool is_iter_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
1271 struct btf *btf, u32 btf_id, int nr_slots)
1273 struct bpf_func_state *state = func(env, reg);
1276 spi = iter_get_spi(env, reg, nr_slots);
1280 for (i = 0; i < nr_slots; i++) {
1281 struct bpf_stack_state *slot = &state->stack[spi - i];
1282 struct bpf_reg_state *st = &slot->spilled_ptr;
1284 /* only main (first) slot has ref_obj_id set */
1285 if (i == 0 && !st->ref_obj_id)
1287 if (i != 0 && st->ref_obj_id)
1289 if (st->iter.btf != btf || st->iter.btf_id != btf_id)
1292 for (j = 0; j < BPF_REG_SIZE; j++)
1293 if (slot->slot_type[j] != STACK_ITER)
1300 /* Check if given stack slot is "special":
1301 * - spilled register state (STACK_SPILL);
1302 * - dynptr state (STACK_DYNPTR);
1303 * - iter state (STACK_ITER).
1305 static bool is_stack_slot_special(const struct bpf_stack_state *stack)
1307 enum bpf_stack_slot_type type = stack->slot_type[BPF_REG_SIZE - 1];
1319 WARN_ONCE(1, "unknown stack slot type %d\n", type);
1324 /* The reg state of a pointer or a bounded scalar was saved when
1325 * it was spilled to the stack.
1327 static bool is_spilled_reg(const struct bpf_stack_state *stack)
1329 return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL;
1332 static bool is_spilled_scalar_reg(const struct bpf_stack_state *stack)
1334 return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL &&
1335 stack->spilled_ptr.type == SCALAR_VALUE;
1338 static void scrub_spilled_slot(u8 *stype)
1340 if (*stype != STACK_INVALID)
1341 *stype = STACK_MISC;
1344 static void print_verifier_state(struct bpf_verifier_env *env,
1345 const struct bpf_func_state *state,
1348 const struct bpf_reg_state *reg;
1349 enum bpf_reg_type t;
1353 verbose(env, " frame%d:", state->frameno);
1354 for (i = 0; i < MAX_BPF_REG; i++) {
1355 reg = &state->regs[i];
1359 if (!print_all && !reg_scratched(env, i))
1361 verbose(env, " R%d", i);
1362 print_liveness(env, reg->live);
1364 if (t == SCALAR_VALUE && reg->precise)
1366 if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
1367 tnum_is_const(reg->var_off)) {
1368 /* reg->off should be 0 for SCALAR_VALUE */
1369 verbose(env, "%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
1370 verbose(env, "%lld", reg->var_off.value + reg->off);
1372 const char *sep = "";
1374 verbose(env, "%s", reg_type_str(env, t));
1375 if (base_type(t) == PTR_TO_BTF_ID)
1376 verbose(env, "%s", btf_type_name(reg->btf, reg->btf_id));
1379 * _a stands for append, was shortened to avoid multiline statements below.
1380 * This macro is used to output a comma separated list of attributes.
1382 #define verbose_a(fmt, ...) ({ verbose(env, "%s" fmt, sep, __VA_ARGS__); sep = ","; })
1385 verbose_a("id=%d", reg->id);
1386 if (reg->ref_obj_id)
1387 verbose_a("ref_obj_id=%d", reg->ref_obj_id);
1388 if (type_is_non_owning_ref(reg->type))
1389 verbose_a("%s", "non_own_ref");
1390 if (t != SCALAR_VALUE)
1391 verbose_a("off=%d", reg->off);
1392 if (type_is_pkt_pointer(t))
1393 verbose_a("r=%d", reg->range);
1394 else if (base_type(t) == CONST_PTR_TO_MAP ||
1395 base_type(t) == PTR_TO_MAP_KEY ||
1396 base_type(t) == PTR_TO_MAP_VALUE)
1397 verbose_a("ks=%d,vs=%d",
1398 reg->map_ptr->key_size,
1399 reg->map_ptr->value_size);
1400 if (tnum_is_const(reg->var_off)) {
1401 /* Typically an immediate SCALAR_VALUE, but
1402 * could be a pointer whose offset is too big
1405 verbose_a("imm=%llx", reg->var_off.value);
1407 if (reg->smin_value != reg->umin_value &&
1408 reg->smin_value != S64_MIN)
1409 verbose_a("smin=%lld", (long long)reg->smin_value);
1410 if (reg->smax_value != reg->umax_value &&
1411 reg->smax_value != S64_MAX)
1412 verbose_a("smax=%lld", (long long)reg->smax_value);
1413 if (reg->umin_value != 0)
1414 verbose_a("umin=%llu", (unsigned long long)reg->umin_value);
1415 if (reg->umax_value != U64_MAX)
1416 verbose_a("umax=%llu", (unsigned long long)reg->umax_value);
1417 if (!tnum_is_unknown(reg->var_off)) {
1420 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
1421 verbose_a("var_off=%s", tn_buf);
1423 if (reg->s32_min_value != reg->smin_value &&
1424 reg->s32_min_value != S32_MIN)
1425 verbose_a("s32_min=%d", (int)(reg->s32_min_value));
1426 if (reg->s32_max_value != reg->smax_value &&
1427 reg->s32_max_value != S32_MAX)
1428 verbose_a("s32_max=%d", (int)(reg->s32_max_value));
1429 if (reg->u32_min_value != reg->umin_value &&
1430 reg->u32_min_value != U32_MIN)
1431 verbose_a("u32_min=%d", (int)(reg->u32_min_value));
1432 if (reg->u32_max_value != reg->umax_value &&
1433 reg->u32_max_value != U32_MAX)
1434 verbose_a("u32_max=%d", (int)(reg->u32_max_value));
1441 for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
1442 char types_buf[BPF_REG_SIZE + 1];
1446 for (j = 0; j < BPF_REG_SIZE; j++) {
1447 if (state->stack[i].slot_type[j] != STACK_INVALID)
1449 types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
1451 types_buf[BPF_REG_SIZE] = 0;
1454 if (!print_all && !stack_slot_scratched(env, i))
1456 switch (state->stack[i].slot_type[BPF_REG_SIZE - 1]) {
1458 reg = &state->stack[i].spilled_ptr;
1461 verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1462 print_liveness(env, reg->live);
1463 verbose(env, "=%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
1464 if (t == SCALAR_VALUE && reg->precise)
1466 if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
1467 verbose(env, "%lld", reg->var_off.value + reg->off);
1470 i += BPF_DYNPTR_NR_SLOTS - 1;
1471 reg = &state->stack[i].spilled_ptr;
1473 verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1474 print_liveness(env, reg->live);
1475 verbose(env, "=dynptr_%s", dynptr_type_str(reg->dynptr.type));
1476 if (reg->ref_obj_id)
1477 verbose(env, "(ref_id=%d)", reg->ref_obj_id);
1480 /* only main slot has ref_obj_id set; skip others */
1481 reg = &state->stack[i].spilled_ptr;
1482 if (!reg->ref_obj_id)
1485 verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1486 print_liveness(env, reg->live);
1487 verbose(env, "=iter_%s(ref_id=%d,state=%s,depth=%u)",
1488 iter_type_str(reg->iter.btf, reg->iter.btf_id),
1489 reg->ref_obj_id, iter_state_str(reg->iter.state),
1495 reg = &state->stack[i].spilled_ptr;
1497 for (j = 0; j < BPF_REG_SIZE; j++)
1498 types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
1499 types_buf[BPF_REG_SIZE] = 0;
1501 verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1502 print_liveness(env, reg->live);
1503 verbose(env, "=%s", types_buf);
1507 if (state->acquired_refs && state->refs[0].id) {
1508 verbose(env, " refs=%d", state->refs[0].id);
1509 for (i = 1; i < state->acquired_refs; i++)
1510 if (state->refs[i].id)
1511 verbose(env, ",%d", state->refs[i].id);
1513 if (state->in_callback_fn)
1514 verbose(env, " cb");
1515 if (state->in_async_callback_fn)
1516 verbose(env, " async_cb");
1519 mark_verifier_state_clean(env);
1522 static inline u32 vlog_alignment(u32 pos)
1524 return round_up(max(pos + BPF_LOG_MIN_ALIGNMENT / 2, BPF_LOG_ALIGNMENT),
1525 BPF_LOG_MIN_ALIGNMENT) - pos - 1;
1528 static void print_insn_state(struct bpf_verifier_env *env,
1529 const struct bpf_func_state *state)
1531 if (env->prev_log_pos && env->prev_log_pos == env->log.end_pos) {
1532 /* remove new line character */
1533 bpf_vlog_reset(&env->log, env->prev_log_pos - 1);
1534 verbose(env, "%*c;", vlog_alignment(env->prev_insn_print_pos), ' ');
1536 verbose(env, "%d:", env->insn_idx);
1538 print_verifier_state(env, state, false);
1541 /* copy array src of length n * size bytes to dst. dst is reallocated if it's too
1542 * small to hold src. This is different from krealloc since we don't want to preserve
1543 * the contents of dst.
1545 * Leaves dst untouched if src is NULL or length is zero. Returns NULL if memory could
1548 static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t flags)
1554 if (ZERO_OR_NULL_PTR(src))
1557 if (unlikely(check_mul_overflow(n, size, &bytes)))
1560 alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes));
1561 dst = krealloc(orig, alloc_bytes, flags);
1567 memcpy(dst, src, bytes);
1569 return dst ? dst : ZERO_SIZE_PTR;
1572 /* resize an array from old_n items to new_n items. the array is reallocated if it's too
1573 * small to hold new_n items. new items are zeroed out if the array grows.
1575 * Contrary to krealloc_array, does not free arr if new_n is zero.
1577 static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
1582 if (!new_n || old_n == new_n)
1585 alloc_size = kmalloc_size_roundup(size_mul(new_n, size));
1586 new_arr = krealloc(arr, alloc_size, GFP_KERNEL);
1594 memset(arr + old_n * size, 0, (new_n - old_n) * size);
1597 return arr ? arr : ZERO_SIZE_PTR;
1600 static int copy_reference_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
1602 dst->refs = copy_array(dst->refs, src->refs, src->acquired_refs,
1603 sizeof(struct bpf_reference_state), GFP_KERNEL);
1607 dst->acquired_refs = src->acquired_refs;
1611 static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
1613 size_t n = src->allocated_stack / BPF_REG_SIZE;
1615 dst->stack = copy_array(dst->stack, src->stack, n, sizeof(struct bpf_stack_state),
1620 dst->allocated_stack = src->allocated_stack;
1624 static int resize_reference_state(struct bpf_func_state *state, size_t n)
1626 state->refs = realloc_array(state->refs, state->acquired_refs, n,
1627 sizeof(struct bpf_reference_state));
1631 state->acquired_refs = n;
1635 static int grow_stack_state(struct bpf_func_state *state, int size)
1637 size_t old_n = state->allocated_stack / BPF_REG_SIZE, n = size / BPF_REG_SIZE;
1642 state->stack = realloc_array(state->stack, old_n, n, sizeof(struct bpf_stack_state));
1646 state->allocated_stack = size;
1650 /* Acquire a pointer id from the env and update the state->refs to include
1651 * this new pointer reference.
1652 * On success, returns a valid pointer id to associate with the register
1653 * On failure, returns a negative errno.
1655 static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
1657 struct bpf_func_state *state = cur_func(env);
1658 int new_ofs = state->acquired_refs;
1661 err = resize_reference_state(state, state->acquired_refs + 1);
1665 state->refs[new_ofs].id = id;
1666 state->refs[new_ofs].insn_idx = insn_idx;
1667 state->refs[new_ofs].callback_ref = state->in_callback_fn ? state->frameno : 0;
1672 /* release function corresponding to acquire_reference_state(). Idempotent. */
1673 static int release_reference_state(struct bpf_func_state *state, int ptr_id)
1677 last_idx = state->acquired_refs - 1;
1678 for (i = 0; i < state->acquired_refs; i++) {
1679 if (state->refs[i].id == ptr_id) {
1680 /* Cannot release caller references in callbacks */
1681 if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
1683 if (last_idx && i != last_idx)
1684 memcpy(&state->refs[i], &state->refs[last_idx],
1685 sizeof(*state->refs));
1686 memset(&state->refs[last_idx], 0, sizeof(*state->refs));
1687 state->acquired_refs--;
1694 static void free_func_state(struct bpf_func_state *state)
1699 kfree(state->stack);
1703 static void clear_jmp_history(struct bpf_verifier_state *state)
1705 kfree(state->jmp_history);
1706 state->jmp_history = NULL;
1707 state->jmp_history_cnt = 0;
1710 static void free_verifier_state(struct bpf_verifier_state *state,
1715 for (i = 0; i <= state->curframe; i++) {
1716 free_func_state(state->frame[i]);
1717 state->frame[i] = NULL;
1719 clear_jmp_history(state);
1724 /* copy verifier state from src to dst growing dst stack space
1725 * when necessary to accommodate larger src stack
1727 static int copy_func_state(struct bpf_func_state *dst,
1728 const struct bpf_func_state *src)
1732 memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
1733 err = copy_reference_state(dst, src);
1736 return copy_stack_state(dst, src);
1739 static int copy_verifier_state(struct bpf_verifier_state *dst_state,
1740 const struct bpf_verifier_state *src)
1742 struct bpf_func_state *dst;
1745 dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history,
1746 src->jmp_history_cnt, sizeof(struct bpf_idx_pair),
1748 if (!dst_state->jmp_history)
1750 dst_state->jmp_history_cnt = src->jmp_history_cnt;
1752 /* if dst has more stack frames then src frame, free them */
1753 for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
1754 free_func_state(dst_state->frame[i]);
1755 dst_state->frame[i] = NULL;
1757 dst_state->speculative = src->speculative;
1758 dst_state->active_rcu_lock = src->active_rcu_lock;
1759 dst_state->curframe = src->curframe;
1760 dst_state->active_lock.ptr = src->active_lock.ptr;
1761 dst_state->active_lock.id = src->active_lock.id;
1762 dst_state->branches = src->branches;
1763 dst_state->parent = src->parent;
1764 dst_state->first_insn_idx = src->first_insn_idx;
1765 dst_state->last_insn_idx = src->last_insn_idx;
1766 for (i = 0; i <= src->curframe; i++) {
1767 dst = dst_state->frame[i];
1769 dst = kzalloc(sizeof(*dst), GFP_KERNEL);
1772 dst_state->frame[i] = dst;
1774 err = copy_func_state(dst, src->frame[i]);
1781 static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
1784 u32 br = --st->branches;
1786 /* WARN_ON(br > 1) technically makes sense here,
1787 * but see comment in push_stack(), hence:
1789 WARN_ONCE((int)br < 0,
1790 "BUG update_branch_counts:branches_to_explore=%d\n",
1798 static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
1799 int *insn_idx, bool pop_log)
1801 struct bpf_verifier_state *cur = env->cur_state;
1802 struct bpf_verifier_stack_elem *elem, *head = env->head;
1805 if (env->head == NULL)
1809 err = copy_verifier_state(cur, &head->st);
1814 bpf_vlog_reset(&env->log, head->log_pos);
1816 *insn_idx = head->insn_idx;
1818 *prev_insn_idx = head->prev_insn_idx;
1820 free_verifier_state(&head->st, false);
1827 static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
1828 int insn_idx, int prev_insn_idx,
1831 struct bpf_verifier_state *cur = env->cur_state;
1832 struct bpf_verifier_stack_elem *elem;
1835 elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
1839 elem->insn_idx = insn_idx;
1840 elem->prev_insn_idx = prev_insn_idx;
1841 elem->next = env->head;
1842 elem->log_pos = env->log.end_pos;
1845 err = copy_verifier_state(&elem->st, cur);
1848 elem->st.speculative |= speculative;
1849 if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
1850 verbose(env, "The sequence of %d jumps is too complex.\n",
1854 if (elem->st.parent) {
1855 ++elem->st.parent->branches;
1856 /* WARN_ON(branches > 2) technically makes sense here,
1858 * 1. speculative states will bump 'branches' for non-branch
1860 * 2. is_state_visited() heuristics may decide not to create
1861 * a new state for a sequence of branches and all such current
1862 * and cloned states will be pointing to a single parent state
1863 * which might have large 'branches' count.
1868 free_verifier_state(env->cur_state, true);
1869 env->cur_state = NULL;
1870 /* pop all elements and return */
1871 while (!pop_stack(env, NULL, NULL, false));
1875 #define CALLER_SAVED_REGS 6
1876 static const int caller_saved[CALLER_SAVED_REGS] = {
1877 BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
1880 /* This helper doesn't clear reg->id */
1881 static void ___mark_reg_known(struct bpf_reg_state *reg, u64 imm)
1883 reg->var_off = tnum_const(imm);
1884 reg->smin_value = (s64)imm;
1885 reg->smax_value = (s64)imm;
1886 reg->umin_value = imm;
1887 reg->umax_value = imm;
1889 reg->s32_min_value = (s32)imm;
1890 reg->s32_max_value = (s32)imm;
1891 reg->u32_min_value = (u32)imm;
1892 reg->u32_max_value = (u32)imm;
1895 /* Mark the unknown part of a register (variable offset or scalar value) as
1896 * known to have the value @imm.
1898 static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm)
1900 /* Clear off and union(map_ptr, range) */
1901 memset(((u8 *)reg) + sizeof(reg->type), 0,
1902 offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type));
1904 reg->ref_obj_id = 0;
1905 ___mark_reg_known(reg, imm);
1908 static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm)
1910 reg->var_off = tnum_const_subreg(reg->var_off, imm);
1911 reg->s32_min_value = (s32)imm;
1912 reg->s32_max_value = (s32)imm;
1913 reg->u32_min_value = (u32)imm;
1914 reg->u32_max_value = (u32)imm;
1917 /* Mark the 'variable offset' part of a register as zero. This should be
1918 * used only on registers holding a pointer type.
1920 static void __mark_reg_known_zero(struct bpf_reg_state *reg)
1922 __mark_reg_known(reg, 0);
1925 static void __mark_reg_const_zero(struct bpf_reg_state *reg)
1927 __mark_reg_known(reg, 0);
1928 reg->type = SCALAR_VALUE;
1931 static void mark_reg_known_zero(struct bpf_verifier_env *env,
1932 struct bpf_reg_state *regs, u32 regno)
1934 if (WARN_ON(regno >= MAX_BPF_REG)) {
1935 verbose(env, "mark_reg_known_zero(regs, %u)\n", regno);
1936 /* Something bad happened, let's kill all regs */
1937 for (regno = 0; regno < MAX_BPF_REG; regno++)
1938 __mark_reg_not_init(env, regs + regno);
1941 __mark_reg_known_zero(regs + regno);
1944 static void __mark_dynptr_reg(struct bpf_reg_state *reg, enum bpf_dynptr_type type,
1945 bool first_slot, int dynptr_id)
1947 /* reg->type has no meaning for STACK_DYNPTR, but when we set reg for
1948 * callback arguments, it does need to be CONST_PTR_TO_DYNPTR, so simply
1949 * set it unconditionally as it is ignored for STACK_DYNPTR anyway.
1951 __mark_reg_known_zero(reg);
1952 reg->type = CONST_PTR_TO_DYNPTR;
1953 /* Give each dynptr a unique id to uniquely associate slices to it. */
1954 reg->id = dynptr_id;
1955 reg->dynptr.type = type;
1956 reg->dynptr.first_slot = first_slot;
1959 static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
1961 if (base_type(reg->type) == PTR_TO_MAP_VALUE) {
1962 const struct bpf_map *map = reg->map_ptr;
1964 if (map->inner_map_meta) {
1965 reg->type = CONST_PTR_TO_MAP;
1966 reg->map_ptr = map->inner_map_meta;
1967 /* transfer reg's id which is unique for every map_lookup_elem
1968 * as UID of the inner map.
1970 if (btf_record_has_field(map->inner_map_meta->record, BPF_TIMER))
1971 reg->map_uid = reg->id;
1972 } else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
1973 reg->type = PTR_TO_XDP_SOCK;
1974 } else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
1975 map->map_type == BPF_MAP_TYPE_SOCKHASH) {
1976 reg->type = PTR_TO_SOCKET;
1978 reg->type = PTR_TO_MAP_VALUE;
1983 reg->type &= ~PTR_MAYBE_NULL;
1986 static void mark_reg_graph_node(struct bpf_reg_state *regs, u32 regno,
1987 struct btf_field_graph_root *ds_head)
1989 __mark_reg_known_zero(®s[regno]);
1990 regs[regno].type = PTR_TO_BTF_ID | MEM_ALLOC;
1991 regs[regno].btf = ds_head->btf;
1992 regs[regno].btf_id = ds_head->value_btf_id;
1993 regs[regno].off = ds_head->node_offset;
1996 static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
1998 return type_is_pkt_pointer(reg->type);
2001 static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
2003 return reg_is_pkt_pointer(reg) ||
2004 reg->type == PTR_TO_PACKET_END;
2007 static bool reg_is_dynptr_slice_pkt(const struct bpf_reg_state *reg)
2009 return base_type(reg->type) == PTR_TO_MEM &&
2010 (reg->type & DYNPTR_TYPE_SKB || reg->type & DYNPTR_TYPE_XDP);
2013 /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
2014 static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
2015 enum bpf_reg_type which)
2017 /* The register can already have a range from prior markings.
2018 * This is fine as long as it hasn't been advanced from its
2021 return reg->type == which &&
2024 tnum_equals_const(reg->var_off, 0);
2027 /* Reset the min/max bounds of a register */
2028 static void __mark_reg_unbounded(struct bpf_reg_state *reg)
2030 reg->smin_value = S64_MIN;
2031 reg->smax_value = S64_MAX;
2032 reg->umin_value = 0;
2033 reg->umax_value = U64_MAX;
2035 reg->s32_min_value = S32_MIN;
2036 reg->s32_max_value = S32_MAX;
2037 reg->u32_min_value = 0;
2038 reg->u32_max_value = U32_MAX;
2041 static void __mark_reg64_unbounded(struct bpf_reg_state *reg)
2043 reg->smin_value = S64_MIN;
2044 reg->smax_value = S64_MAX;
2045 reg->umin_value = 0;
2046 reg->umax_value = U64_MAX;
2049 static void __mark_reg32_unbounded(struct bpf_reg_state *reg)
2051 reg->s32_min_value = S32_MIN;
2052 reg->s32_max_value = S32_MAX;
2053 reg->u32_min_value = 0;
2054 reg->u32_max_value = U32_MAX;
2057 static void __update_reg32_bounds(struct bpf_reg_state *reg)
2059 struct tnum var32_off = tnum_subreg(reg->var_off);
2061 /* min signed is max(sign bit) | min(other bits) */
2062 reg->s32_min_value = max_t(s32, reg->s32_min_value,
2063 var32_off.value | (var32_off.mask & S32_MIN));
2064 /* max signed is min(sign bit) | max(other bits) */
2065 reg->s32_max_value = min_t(s32, reg->s32_max_value,
2066 var32_off.value | (var32_off.mask & S32_MAX));
2067 reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value);
2068 reg->u32_max_value = min(reg->u32_max_value,
2069 (u32)(var32_off.value | var32_off.mask));
2072 static void __update_reg64_bounds(struct bpf_reg_state *reg)
2074 /* min signed is max(sign bit) | min(other bits) */
2075 reg->smin_value = max_t(s64, reg->smin_value,
2076 reg->var_off.value | (reg->var_off.mask & S64_MIN));
2077 /* max signed is min(sign bit) | max(other bits) */
2078 reg->smax_value = min_t(s64, reg->smax_value,
2079 reg->var_off.value | (reg->var_off.mask & S64_MAX));
2080 reg->umin_value = max(reg->umin_value, reg->var_off.value);
2081 reg->umax_value = min(reg->umax_value,
2082 reg->var_off.value | reg->var_off.mask);
2085 static void __update_reg_bounds(struct bpf_reg_state *reg)
2087 __update_reg32_bounds(reg);
2088 __update_reg64_bounds(reg);
2091 /* Uses signed min/max values to inform unsigned, and vice-versa */
2092 static void __reg32_deduce_bounds(struct bpf_reg_state *reg)
2094 /* Learn sign from signed bounds.
2095 * If we cannot cross the sign boundary, then signed and unsigned bounds
2096 * are the same, so combine. This works even in the negative case, e.g.
2097 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
2099 if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) {
2100 reg->s32_min_value = reg->u32_min_value =
2101 max_t(u32, reg->s32_min_value, reg->u32_min_value);
2102 reg->s32_max_value = reg->u32_max_value =
2103 min_t(u32, reg->s32_max_value, reg->u32_max_value);
2106 /* Learn sign from unsigned bounds. Signed bounds cross the sign
2107 * boundary, so we must be careful.
2109 if ((s32)reg->u32_max_value >= 0) {
2110 /* Positive. We can't learn anything from the smin, but smax
2111 * is positive, hence safe.
2113 reg->s32_min_value = reg->u32_min_value;
2114 reg->s32_max_value = reg->u32_max_value =
2115 min_t(u32, reg->s32_max_value, reg->u32_max_value);
2116 } else if ((s32)reg->u32_min_value < 0) {
2117 /* Negative. We can't learn anything from the smax, but smin
2118 * is negative, hence safe.
2120 reg->s32_min_value = reg->u32_min_value =
2121 max_t(u32, reg->s32_min_value, reg->u32_min_value);
2122 reg->s32_max_value = reg->u32_max_value;
2126 static void __reg64_deduce_bounds(struct bpf_reg_state *reg)
2128 /* Learn sign from signed bounds.
2129 * If we cannot cross the sign boundary, then signed and unsigned bounds
2130 * are the same, so combine. This works even in the negative case, e.g.
2131 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
2133 if (reg->smin_value >= 0 || reg->smax_value < 0) {
2134 reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
2136 reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
2140 /* Learn sign from unsigned bounds. Signed bounds cross the sign
2141 * boundary, so we must be careful.
2143 if ((s64)reg->umax_value >= 0) {
2144 /* Positive. We can't learn anything from the smin, but smax
2145 * is positive, hence safe.
2147 reg->smin_value = reg->umin_value;
2148 reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
2150 } else if ((s64)reg->umin_value < 0) {
2151 /* Negative. We can't learn anything from the smax, but smin
2152 * is negative, hence safe.
2154 reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
2156 reg->smax_value = reg->umax_value;
2160 static void __reg_deduce_bounds(struct bpf_reg_state *reg)
2162 __reg32_deduce_bounds(reg);
2163 __reg64_deduce_bounds(reg);
2166 /* Attempts to improve var_off based on unsigned min/max information */
2167 static void __reg_bound_offset(struct bpf_reg_state *reg)
2169 struct tnum var64_off = tnum_intersect(reg->var_off,
2170 tnum_range(reg->umin_value,
2172 struct tnum var32_off = tnum_intersect(tnum_subreg(var64_off),
2173 tnum_range(reg->u32_min_value,
2174 reg->u32_max_value));
2176 reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
2179 static void reg_bounds_sync(struct bpf_reg_state *reg)
2181 /* We might have learned new bounds from the var_off. */
2182 __update_reg_bounds(reg);
2183 /* We might have learned something about the sign bit. */
2184 __reg_deduce_bounds(reg);
2185 /* We might have learned some bits from the bounds. */
2186 __reg_bound_offset(reg);
2187 /* Intersecting with the old var_off might have improved our bounds
2188 * slightly, e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
2189 * then new var_off is (0; 0x7f...fc) which improves our umax.
2191 __update_reg_bounds(reg);
2194 static bool __reg32_bound_s64(s32 a)
2196 return a >= 0 && a <= S32_MAX;
2199 static void __reg_assign_32_into_64(struct bpf_reg_state *reg)
2201 reg->umin_value = reg->u32_min_value;
2202 reg->umax_value = reg->u32_max_value;
2204 /* Attempt to pull 32-bit signed bounds into 64-bit bounds but must
2205 * be positive otherwise set to worse case bounds and refine later
2208 if (__reg32_bound_s64(reg->s32_min_value) &&
2209 __reg32_bound_s64(reg->s32_max_value)) {
2210 reg->smin_value = reg->s32_min_value;
2211 reg->smax_value = reg->s32_max_value;
2213 reg->smin_value = 0;
2214 reg->smax_value = U32_MAX;
2218 static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
2220 /* special case when 64-bit register has upper 32-bit register
2221 * zeroed. Typically happens after zext or <<32, >>32 sequence
2222 * allowing us to use 32-bit bounds directly,
2224 if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) {
2225 __reg_assign_32_into_64(reg);
2227 /* Otherwise the best we can do is push lower 32bit known and
2228 * unknown bits into register (var_off set from jmp logic)
2229 * then learn as much as possible from the 64-bit tnum
2230 * known and unknown bits. The previous smin/smax bounds are
2231 * invalid here because of jmp32 compare so mark them unknown
2232 * so they do not impact tnum bounds calculation.
2234 __mark_reg64_unbounded(reg);
2236 reg_bounds_sync(reg);
2239 static bool __reg64_bound_s32(s64 a)
2241 return a >= S32_MIN && a <= S32_MAX;
2244 static bool __reg64_bound_u32(u64 a)
2246 return a >= U32_MIN && a <= U32_MAX;
2249 static void __reg_combine_64_into_32(struct bpf_reg_state *reg)
2251 __mark_reg32_unbounded(reg);
2252 if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {
2253 reg->s32_min_value = (s32)reg->smin_value;
2254 reg->s32_max_value = (s32)reg->smax_value;
2256 if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {
2257 reg->u32_min_value = (u32)reg->umin_value;
2258 reg->u32_max_value = (u32)reg->umax_value;
2260 reg_bounds_sync(reg);
2263 /* Mark a register as having a completely unknown (scalar) value. */
2264 static void __mark_reg_unknown(const struct bpf_verifier_env *env,
2265 struct bpf_reg_state *reg)
2268 * Clear type, off, and union(map_ptr, range) and
2269 * padding between 'type' and union
2271 memset(reg, 0, offsetof(struct bpf_reg_state, var_off));
2272 reg->type = SCALAR_VALUE;
2274 reg->ref_obj_id = 0;
2275 reg->var_off = tnum_unknown;
2277 reg->precise = !env->bpf_capable;
2278 __mark_reg_unbounded(reg);
2281 static void mark_reg_unknown(struct bpf_verifier_env *env,
2282 struct bpf_reg_state *regs, u32 regno)
2284 if (WARN_ON(regno >= MAX_BPF_REG)) {
2285 verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
2286 /* Something bad happened, let's kill all regs except FP */
2287 for (regno = 0; regno < BPF_REG_FP; regno++)
2288 __mark_reg_not_init(env, regs + regno);
2291 __mark_reg_unknown(env, regs + regno);
2294 static void __mark_reg_not_init(const struct bpf_verifier_env *env,
2295 struct bpf_reg_state *reg)
2297 __mark_reg_unknown(env, reg);
2298 reg->type = NOT_INIT;
2301 static void mark_reg_not_init(struct bpf_verifier_env *env,
2302 struct bpf_reg_state *regs, u32 regno)
2304 if (WARN_ON(regno >= MAX_BPF_REG)) {
2305 verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
2306 /* Something bad happened, let's kill all regs except FP */
2307 for (regno = 0; regno < BPF_REG_FP; regno++)
2308 __mark_reg_not_init(env, regs + regno);
2311 __mark_reg_not_init(env, regs + regno);
2314 static void mark_btf_ld_reg(struct bpf_verifier_env *env,
2315 struct bpf_reg_state *regs, u32 regno,
2316 enum bpf_reg_type reg_type,
2317 struct btf *btf, u32 btf_id,
2318 enum bpf_type_flag flag)
2320 if (reg_type == SCALAR_VALUE) {
2321 mark_reg_unknown(env, regs, regno);
2324 mark_reg_known_zero(env, regs, regno);
2325 regs[regno].type = PTR_TO_BTF_ID | flag;
2326 regs[regno].btf = btf;
2327 regs[regno].btf_id = btf_id;
2330 #define DEF_NOT_SUBREG (0)
2331 static void init_reg_state(struct bpf_verifier_env *env,
2332 struct bpf_func_state *state)
2334 struct bpf_reg_state *regs = state->regs;
2337 for (i = 0; i < MAX_BPF_REG; i++) {
2338 mark_reg_not_init(env, regs, i);
2339 regs[i].live = REG_LIVE_NONE;
2340 regs[i].parent = NULL;
2341 regs[i].subreg_def = DEF_NOT_SUBREG;
2345 regs[BPF_REG_FP].type = PTR_TO_STACK;
2346 mark_reg_known_zero(env, regs, BPF_REG_FP);
2347 regs[BPF_REG_FP].frameno = state->frameno;
2350 #define BPF_MAIN_FUNC (-1)
2351 static void init_func_state(struct bpf_verifier_env *env,
2352 struct bpf_func_state *state,
2353 int callsite, int frameno, int subprogno)
2355 state->callsite = callsite;
2356 state->frameno = frameno;
2357 state->subprogno = subprogno;
2358 state->callback_ret_range = tnum_range(0, 0);
2359 init_reg_state(env, state);
2360 mark_verifier_state_scratched(env);
2363 /* Similar to push_stack(), but for async callbacks */
2364 static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env,
2365 int insn_idx, int prev_insn_idx,
2368 struct bpf_verifier_stack_elem *elem;
2369 struct bpf_func_state *frame;
2371 elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
2375 elem->insn_idx = insn_idx;
2376 elem->prev_insn_idx = prev_insn_idx;
2377 elem->next = env->head;
2378 elem->log_pos = env->log.end_pos;
2381 if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
2383 "The sequence of %d jumps is too complex for async cb.\n",
2387 /* Unlike push_stack() do not copy_verifier_state().
2388 * The caller state doesn't matter.
2389 * This is async callback. It starts in a fresh stack.
2390 * Initialize it similar to do_check_common().
2392 elem->st.branches = 1;
2393 frame = kzalloc(sizeof(*frame), GFP_KERNEL);
2396 init_func_state(env, frame,
2397 BPF_MAIN_FUNC /* callsite */,
2398 0 /* frameno within this callchain */,
2399 subprog /* subprog number within this prog */);
2400 elem->st.frame[0] = frame;
2403 free_verifier_state(env->cur_state, true);
2404 env->cur_state = NULL;
2405 /* pop all elements and return */
2406 while (!pop_stack(env, NULL, NULL, false));
2412 SRC_OP, /* register is used as source operand */
2413 DST_OP, /* register is used as destination operand */
2414 DST_OP_NO_MARK /* same as above, check only, don't mark */
2417 static int cmp_subprogs(const void *a, const void *b)
2419 return ((struct bpf_subprog_info *)a)->start -
2420 ((struct bpf_subprog_info *)b)->start;
2423 static int find_subprog(struct bpf_verifier_env *env, int off)
2425 struct bpf_subprog_info *p;
2427 p = bsearch(&off, env->subprog_info, env->subprog_cnt,
2428 sizeof(env->subprog_info[0]), cmp_subprogs);
2431 return p - env->subprog_info;
2435 static int add_subprog(struct bpf_verifier_env *env, int off)
2437 int insn_cnt = env->prog->len;
2440 if (off >= insn_cnt || off < 0) {
2441 verbose(env, "call to invalid destination\n");
2444 ret = find_subprog(env, off);
2447 if (env->subprog_cnt >= BPF_MAX_SUBPROGS) {
2448 verbose(env, "too many subprograms\n");
2451 /* determine subprog starts. The end is one before the next starts */
2452 env->subprog_info[env->subprog_cnt++].start = off;
2453 sort(env->subprog_info, env->subprog_cnt,
2454 sizeof(env->subprog_info[0]), cmp_subprogs, NULL);
2455 return env->subprog_cnt - 1;
2458 #define MAX_KFUNC_DESCS 256
2459 #define MAX_KFUNC_BTFS 256
2461 struct bpf_kfunc_desc {
2462 struct btf_func_model func_model;
2469 struct bpf_kfunc_btf {
2471 struct module *module;
2475 struct bpf_kfunc_desc_tab {
2476 /* Sorted by func_id (BTF ID) and offset (fd_array offset) during
2477 * verification. JITs do lookups by bpf_insn, where func_id may not be
2478 * available, therefore at the end of verification do_misc_fixups()
2479 * sorts this by imm and offset.
2481 struct bpf_kfunc_desc descs[MAX_KFUNC_DESCS];
2485 struct bpf_kfunc_btf_tab {
2486 struct bpf_kfunc_btf descs[MAX_KFUNC_BTFS];
2490 static int kfunc_desc_cmp_by_id_off(const void *a, const void *b)
2492 const struct bpf_kfunc_desc *d0 = a;
2493 const struct bpf_kfunc_desc *d1 = b;
2495 /* func_id is not greater than BTF_MAX_TYPE */
2496 return d0->func_id - d1->func_id ?: d0->offset - d1->offset;
2499 static int kfunc_btf_cmp_by_off(const void *a, const void *b)
2501 const struct bpf_kfunc_btf *d0 = a;
2502 const struct bpf_kfunc_btf *d1 = b;
2504 return d0->offset - d1->offset;
2507 static const struct bpf_kfunc_desc *
2508 find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
2510 struct bpf_kfunc_desc desc = {
2514 struct bpf_kfunc_desc_tab *tab;
2516 tab = prog->aux->kfunc_tab;
2517 return bsearch(&desc, tab->descs, tab->nr_descs,
2518 sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
2521 int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
2522 u16 btf_fd_idx, u8 **func_addr)
2524 const struct bpf_kfunc_desc *desc;
2526 desc = find_kfunc_desc(prog, func_id, btf_fd_idx);
2530 *func_addr = (u8 *)desc->addr;
2534 static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env,
2537 struct bpf_kfunc_btf kf_btf = { .offset = offset };
2538 struct bpf_kfunc_btf_tab *tab;
2539 struct bpf_kfunc_btf *b;
2544 tab = env->prog->aux->kfunc_btf_tab;
2545 b = bsearch(&kf_btf, tab->descs, tab->nr_descs,
2546 sizeof(tab->descs[0]), kfunc_btf_cmp_by_off);
2548 if (tab->nr_descs == MAX_KFUNC_BTFS) {
2549 verbose(env, "too many different module BTFs\n");
2550 return ERR_PTR(-E2BIG);
2553 if (bpfptr_is_null(env->fd_array)) {
2554 verbose(env, "kfunc offset > 0 without fd_array is invalid\n");
2555 return ERR_PTR(-EPROTO);
2558 if (copy_from_bpfptr_offset(&btf_fd, env->fd_array,
2559 offset * sizeof(btf_fd),
2561 return ERR_PTR(-EFAULT);
2563 btf = btf_get_by_fd(btf_fd);
2565 verbose(env, "invalid module BTF fd specified\n");
2569 if (!btf_is_module(btf)) {
2570 verbose(env, "BTF fd for kfunc is not a module BTF\n");
2572 return ERR_PTR(-EINVAL);
2575 mod = btf_try_get_module(btf);
2578 return ERR_PTR(-ENXIO);
2581 b = &tab->descs[tab->nr_descs++];
2586 sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
2587 kfunc_btf_cmp_by_off, NULL);
2592 void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab)
2597 while (tab->nr_descs--) {
2598 module_put(tab->descs[tab->nr_descs].module);
2599 btf_put(tab->descs[tab->nr_descs].btf);
2604 static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
2608 /* In the future, this can be allowed to increase limit
2609 * of fd index into fd_array, interpreted as u16.
2611 verbose(env, "negative offset disallowed for kernel module function call\n");
2612 return ERR_PTR(-EINVAL);
2615 return __find_kfunc_desc_btf(env, offset);
2617 return btf_vmlinux ?: ERR_PTR(-ENOENT);
2620 static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
2622 const struct btf_type *func, *func_proto;
2623 struct bpf_kfunc_btf_tab *btf_tab;
2624 struct bpf_kfunc_desc_tab *tab;
2625 struct bpf_prog_aux *prog_aux;
2626 struct bpf_kfunc_desc *desc;
2627 const char *func_name;
2628 struct btf *desc_btf;
2629 unsigned long call_imm;
2633 prog_aux = env->prog->aux;
2634 tab = prog_aux->kfunc_tab;
2635 btf_tab = prog_aux->kfunc_btf_tab;
2638 verbose(env, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n");
2642 if (!env->prog->jit_requested) {
2643 verbose(env, "JIT is required for calling kernel function\n");
2647 if (!bpf_jit_supports_kfunc_call()) {
2648 verbose(env, "JIT does not support calling kernel function\n");
2652 if (!env->prog->gpl_compatible) {
2653 verbose(env, "cannot call kernel function from non-GPL compatible program\n");
2657 tab = kzalloc(sizeof(*tab), GFP_KERNEL);
2660 prog_aux->kfunc_tab = tab;
2663 /* func_id == 0 is always invalid, but instead of returning an error, be
2664 * conservative and wait until the code elimination pass before returning
2665 * error, so that invalid calls that get pruned out can be in BPF programs
2666 * loaded from userspace. It is also required that offset be untouched
2669 if (!func_id && !offset)
2672 if (!btf_tab && offset) {
2673 btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL);
2676 prog_aux->kfunc_btf_tab = btf_tab;
2679 desc_btf = find_kfunc_desc_btf(env, offset);
2680 if (IS_ERR(desc_btf)) {
2681 verbose(env, "failed to find BTF for kernel function\n");
2682 return PTR_ERR(desc_btf);
2685 if (find_kfunc_desc(env->prog, func_id, offset))
2688 if (tab->nr_descs == MAX_KFUNC_DESCS) {
2689 verbose(env, "too many different kernel function calls\n");
2693 func = btf_type_by_id(desc_btf, func_id);
2694 if (!func || !btf_type_is_func(func)) {
2695 verbose(env, "kernel btf_id %u is not a function\n",
2699 func_proto = btf_type_by_id(desc_btf, func->type);
2700 if (!func_proto || !btf_type_is_func_proto(func_proto)) {
2701 verbose(env, "kernel function btf_id %u does not have a valid func_proto\n",
2706 func_name = btf_name_by_offset(desc_btf, func->name_off);
2707 addr = kallsyms_lookup_name(func_name);
2709 verbose(env, "cannot find address for kernel function %s\n",
2713 specialize_kfunc(env, func_id, offset, &addr);
2715 if (bpf_jit_supports_far_kfunc_call()) {
2718 call_imm = BPF_CALL_IMM(addr);
2719 /* Check whether the relative offset overflows desc->imm */
2720 if ((unsigned long)(s32)call_imm != call_imm) {
2721 verbose(env, "address of kernel function %s is out of range\n",
2727 if (bpf_dev_bound_kfunc_id(func_id)) {
2728 err = bpf_dev_bound_kfunc_check(&env->log, prog_aux);
2733 desc = &tab->descs[tab->nr_descs++];
2734 desc->func_id = func_id;
2735 desc->imm = call_imm;
2736 desc->offset = offset;
2738 err = btf_distill_func_proto(&env->log, desc_btf,
2739 func_proto, func_name,
2742 sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
2743 kfunc_desc_cmp_by_id_off, NULL);
2747 static int kfunc_desc_cmp_by_imm_off(const void *a, const void *b)
2749 const struct bpf_kfunc_desc *d0 = a;
2750 const struct bpf_kfunc_desc *d1 = b;
2752 if (d0->imm != d1->imm)
2753 return d0->imm < d1->imm ? -1 : 1;
2754 if (d0->offset != d1->offset)
2755 return d0->offset < d1->offset ? -1 : 1;
2759 static void sort_kfunc_descs_by_imm_off(struct bpf_prog *prog)
2761 struct bpf_kfunc_desc_tab *tab;
2763 tab = prog->aux->kfunc_tab;
2767 sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
2768 kfunc_desc_cmp_by_imm_off, NULL);
2771 bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog)
2773 return !!prog->aux->kfunc_tab;
2776 const struct btf_func_model *
2777 bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
2778 const struct bpf_insn *insn)
2780 const struct bpf_kfunc_desc desc = {
2782 .offset = insn->off,
2784 const struct bpf_kfunc_desc *res;
2785 struct bpf_kfunc_desc_tab *tab;
2787 tab = prog->aux->kfunc_tab;
2788 res = bsearch(&desc, tab->descs, tab->nr_descs,
2789 sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm_off);
2791 return res ? &res->func_model : NULL;
2794 static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
2796 struct bpf_subprog_info *subprog = env->subprog_info;
2797 struct bpf_insn *insn = env->prog->insnsi;
2798 int i, ret, insn_cnt = env->prog->len;
2800 /* Add entry function. */
2801 ret = add_subprog(env, 0);
2805 for (i = 0; i < insn_cnt; i++, insn++) {
2806 if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn) &&
2807 !bpf_pseudo_kfunc_call(insn))
2810 if (!env->bpf_capable) {
2811 verbose(env, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
2815 if (bpf_pseudo_func(insn) || bpf_pseudo_call(insn))
2816 ret = add_subprog(env, i + insn->imm + 1);
2818 ret = add_kfunc_call(env, insn->imm, insn->off);
2824 /* Add a fake 'exit' subprog which could simplify subprog iteration
2825 * logic. 'subprog_cnt' should not be increased.
2827 subprog[env->subprog_cnt].start = insn_cnt;
2829 if (env->log.level & BPF_LOG_LEVEL2)
2830 for (i = 0; i < env->subprog_cnt; i++)
2831 verbose(env, "func#%d @%d\n", i, subprog[i].start);
2836 static int check_subprogs(struct bpf_verifier_env *env)
2838 int i, subprog_start, subprog_end, off, cur_subprog = 0;
2839 struct bpf_subprog_info *subprog = env->subprog_info;
2840 struct bpf_insn *insn = env->prog->insnsi;
2841 int insn_cnt = env->prog->len;
2843 /* now check that all jumps are within the same subprog */
2844 subprog_start = subprog[cur_subprog].start;
2845 subprog_end = subprog[cur_subprog + 1].start;
2846 for (i = 0; i < insn_cnt; i++) {
2847 u8 code = insn[i].code;
2849 if (code == (BPF_JMP | BPF_CALL) &&
2850 insn[i].src_reg == 0 &&
2851 insn[i].imm == BPF_FUNC_tail_call)
2852 subprog[cur_subprog].has_tail_call = true;
2853 if (BPF_CLASS(code) == BPF_LD &&
2854 (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
2855 subprog[cur_subprog].has_ld_abs = true;
2856 if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
2858 if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
2860 if (code == (BPF_JMP32 | BPF_JA))
2861 off = i + insn[i].imm + 1;
2863 off = i + insn[i].off + 1;
2864 if (off < subprog_start || off >= subprog_end) {
2865 verbose(env, "jump out of range from insn %d to %d\n", i, off);
2869 if (i == subprog_end - 1) {
2870 /* to avoid fall-through from one subprog into another
2871 * the last insn of the subprog should be either exit
2872 * or unconditional jump back
2874 if (code != (BPF_JMP | BPF_EXIT) &&
2875 code != (BPF_JMP32 | BPF_JA) &&
2876 code != (BPF_JMP | BPF_JA)) {
2877 verbose(env, "last insn is not an exit or jmp\n");
2880 subprog_start = subprog_end;
2882 if (cur_subprog < env->subprog_cnt)
2883 subprog_end = subprog[cur_subprog + 1].start;
2889 /* Parentage chain of this register (or stack slot) should take care of all
2890 * issues like callee-saved registers, stack slot allocation time, etc.
2892 static int mark_reg_read(struct bpf_verifier_env *env,
2893 const struct bpf_reg_state *state,
2894 struct bpf_reg_state *parent, u8 flag)
2896 bool writes = parent == state->parent; /* Observe write marks */
2900 /* if read wasn't screened by an earlier write ... */
2901 if (writes && state->live & REG_LIVE_WRITTEN)
2903 if (parent->live & REG_LIVE_DONE) {
2904 verbose(env, "verifier BUG type %s var_off %lld off %d\n",
2905 reg_type_str(env, parent->type),
2906 parent->var_off.value, parent->off);
2909 /* The first condition is more likely to be true than the
2910 * second, checked it first.
2912 if ((parent->live & REG_LIVE_READ) == flag ||
2913 parent->live & REG_LIVE_READ64)
2914 /* The parentage chain never changes and
2915 * this parent was already marked as LIVE_READ.
2916 * There is no need to keep walking the chain again and
2917 * keep re-marking all parents as LIVE_READ.
2918 * This case happens when the same register is read
2919 * multiple times without writes into it in-between.
2920 * Also, if parent has the stronger REG_LIVE_READ64 set,
2921 * then no need to set the weak REG_LIVE_READ32.
2924 /* ... then we depend on parent's value */
2925 parent->live |= flag;
2926 /* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
2927 if (flag == REG_LIVE_READ64)
2928 parent->live &= ~REG_LIVE_READ32;
2930 parent = state->parent;
2935 if (env->longest_mark_read_walk < cnt)
2936 env->longest_mark_read_walk = cnt;
2940 static int mark_dynptr_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
2942 struct bpf_func_state *state = func(env, reg);
2945 /* For CONST_PTR_TO_DYNPTR, it must have already been done by
2946 * check_reg_arg in check_helper_call and mark_btf_func_reg_size in
2949 if (reg->type == CONST_PTR_TO_DYNPTR)
2951 spi = dynptr_get_spi(env, reg);
2954 /* Caller ensures dynptr is valid and initialized, which means spi is in
2955 * bounds and spi is the first dynptr slot. Simply mark stack slot as
2958 ret = mark_reg_read(env, &state->stack[spi].spilled_ptr,
2959 state->stack[spi].spilled_ptr.parent, REG_LIVE_READ64);
2962 return mark_reg_read(env, &state->stack[spi - 1].spilled_ptr,
2963 state->stack[spi - 1].spilled_ptr.parent, REG_LIVE_READ64);
2966 static int mark_iter_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
2967 int spi, int nr_slots)
2969 struct bpf_func_state *state = func(env, reg);
2972 for (i = 0; i < nr_slots; i++) {
2973 struct bpf_reg_state *st = &state->stack[spi - i].spilled_ptr;
2975 err = mark_reg_read(env, st, st->parent, REG_LIVE_READ64);
2979 mark_stack_slot_scratched(env, spi - i);
2985 /* This function is supposed to be used by the following 32-bit optimization
2986 * code only. It returns TRUE if the source or destination register operates
2987 * on 64-bit, otherwise return FALSE.
2989 static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
2990 u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
2995 class = BPF_CLASS(code);
2997 if (class == BPF_JMP) {
2998 /* BPF_EXIT for "main" will reach here. Return TRUE
3003 if (op == BPF_CALL) {
3004 /* BPF to BPF call will reach here because of marking
3005 * caller saved clobber with DST_OP_NO_MARK for which we
3006 * don't care the register def because they are anyway
3007 * marked as NOT_INIT already.
3009 if (insn->src_reg == BPF_PSEUDO_CALL)
3011 /* Helper call will reach here because of arg type
3012 * check, conservatively return TRUE.
3021 if (class == BPF_ALU64 && op == BPF_END && (insn->imm == 16 || insn->imm == 32))
3024 if (class == BPF_ALU64 || class == BPF_JMP ||
3025 (class == BPF_ALU && op == BPF_END && insn->imm == 64))
3028 if (class == BPF_ALU || class == BPF_JMP32)
3031 if (class == BPF_LDX) {
3033 return BPF_SIZE(code) == BPF_DW;
3034 /* LDX source must be ptr. */
3038 if (class == BPF_STX) {
3039 /* BPF_STX (including atomic variants) has multiple source
3040 * operands, one of which is a ptr. Check whether the caller is
3043 if (t == SRC_OP && reg->type != SCALAR_VALUE)
3045 return BPF_SIZE(code) == BPF_DW;
3048 if (class == BPF_LD) {
3049 u8 mode = BPF_MODE(code);
3052 if (mode == BPF_IMM)
3055 /* Both LD_IND and LD_ABS return 32-bit data. */
3059 /* Implicit ctx ptr. */
3060 if (regno == BPF_REG_6)
3063 /* Explicit source could be any width. */
3067 if (class == BPF_ST)
3068 /* The only source register for BPF_ST is a ptr. */
3071 /* Conservatively return true at default. */
3075 /* Return the regno defined by the insn, or -1. */
3076 static int insn_def_regno(const struct bpf_insn *insn)
3078 switch (BPF_CLASS(insn->code)) {
3084 if (BPF_MODE(insn->code) == BPF_ATOMIC &&
3085 (insn->imm & BPF_FETCH)) {
3086 if (insn->imm == BPF_CMPXCHG)
3089 return insn->src_reg;
3094 return insn->dst_reg;
3098 /* Return TRUE if INSN has defined any 32-bit value explicitly. */
3099 static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
3101 int dst_reg = insn_def_regno(insn);
3106 return !is_reg64(env, insn, dst_reg, NULL, DST_OP);
3109 static void mark_insn_zext(struct bpf_verifier_env *env,
3110 struct bpf_reg_state *reg)
3112 s32 def_idx = reg->subreg_def;
3114 if (def_idx == DEF_NOT_SUBREG)
3117 env->insn_aux_data[def_idx - 1].zext_dst = true;
3118 /* The dst will be zero extended, so won't be sub-register anymore. */
3119 reg->subreg_def = DEF_NOT_SUBREG;
3122 static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
3123 enum reg_arg_type t)
3125 struct bpf_verifier_state *vstate = env->cur_state;
3126 struct bpf_func_state *state = vstate->frame[vstate->curframe];
3127 struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
3128 struct bpf_reg_state *reg, *regs = state->regs;
3131 if (regno >= MAX_BPF_REG) {
3132 verbose(env, "R%d is invalid\n", regno);
3136 mark_reg_scratched(env, regno);
3139 rw64 = is_reg64(env, insn, regno, reg, t);
3141 /* check whether register used as source operand can be read */
3142 if (reg->type == NOT_INIT) {
3143 verbose(env, "R%d !read_ok\n", regno);
3146 /* We don't need to worry about FP liveness because it's read-only */
3147 if (regno == BPF_REG_FP)
3151 mark_insn_zext(env, reg);
3153 return mark_reg_read(env, reg, reg->parent,
3154 rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
3156 /* check whether register used as dest operand can be written to */
3157 if (regno == BPF_REG_FP) {
3158 verbose(env, "frame pointer is read only\n");
3161 reg->live |= REG_LIVE_WRITTEN;
3162 reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
3164 mark_reg_unknown(env, regs, regno);
3169 static void mark_jmp_point(struct bpf_verifier_env *env, int idx)
3171 env->insn_aux_data[idx].jmp_point = true;
3174 static bool is_jmp_point(struct bpf_verifier_env *env, int insn_idx)
3176 return env->insn_aux_data[insn_idx].jmp_point;
3179 /* for any branch, call, exit record the history of jmps in the given state */
3180 static int push_jmp_history(struct bpf_verifier_env *env,
3181 struct bpf_verifier_state *cur)
3183 u32 cnt = cur->jmp_history_cnt;
3184 struct bpf_idx_pair *p;
3187 if (!is_jmp_point(env, env->insn_idx))
3191 alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p)));
3192 p = krealloc(cur->jmp_history, alloc_size, GFP_USER);
3195 p[cnt - 1].idx = env->insn_idx;
3196 p[cnt - 1].prev_idx = env->prev_insn_idx;
3197 cur->jmp_history = p;
3198 cur->jmp_history_cnt = cnt;
3202 /* Backtrack one insn at a time. If idx is not at the top of recorded
3203 * history then previous instruction came from straight line execution.
3204 * Return -ENOENT if we exhausted all instructions within given state.
3206 * It's legal to have a bit of a looping with the same starting and ending
3207 * insn index within the same state, e.g.: 3->4->5->3, so just because current
3208 * instruction index is the same as state's first_idx doesn't mean we are
3209 * done. If there is still some jump history left, we should keep going. We
3210 * need to take into account that we might have a jump history between given
3211 * state's parent and itself, due to checkpointing. In this case, we'll have
3212 * history entry recording a jump from last instruction of parent state and
3213 * first instruction of given state.
3215 static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
3220 if (i == st->first_insn_idx) {
3223 if (cnt == 1 && st->jmp_history[0].idx == i)
3227 if (cnt && st->jmp_history[cnt - 1].idx == i) {
3228 i = st->jmp_history[cnt - 1].prev_idx;
3236 static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn)
3238 const struct btf_type *func;
3239 struct btf *desc_btf;
3241 if (insn->src_reg != BPF_PSEUDO_KFUNC_CALL)
3244 desc_btf = find_kfunc_desc_btf(data, insn->off);
3245 if (IS_ERR(desc_btf))
3248 func = btf_type_by_id(desc_btf, insn->imm);
3249 return btf_name_by_offset(desc_btf, func->name_off);
3252 static inline void bt_init(struct backtrack_state *bt, u32 frame)
3257 static inline void bt_reset(struct backtrack_state *bt)
3259 struct bpf_verifier_env *env = bt->env;
3261 memset(bt, 0, sizeof(*bt));
3265 static inline u32 bt_empty(struct backtrack_state *bt)
3270 for (i = 0; i <= bt->frame; i++)
3271 mask |= bt->reg_masks[i] | bt->stack_masks[i];
3276 static inline int bt_subprog_enter(struct backtrack_state *bt)
3278 if (bt->frame == MAX_CALL_FRAMES - 1) {
3279 verbose(bt->env, "BUG subprog enter from frame %d\n", bt->frame);
3280 WARN_ONCE(1, "verifier backtracking bug");
3287 static inline int bt_subprog_exit(struct backtrack_state *bt)
3289 if (bt->frame == 0) {
3290 verbose(bt->env, "BUG subprog exit from frame 0\n");
3291 WARN_ONCE(1, "verifier backtracking bug");
3298 static inline void bt_set_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
3300 bt->reg_masks[frame] |= 1 << reg;
3303 static inline void bt_clear_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
3305 bt->reg_masks[frame] &= ~(1 << reg);
3308 static inline void bt_set_reg(struct backtrack_state *bt, u32 reg)
3310 bt_set_frame_reg(bt, bt->frame, reg);
3313 static inline void bt_clear_reg(struct backtrack_state *bt, u32 reg)
3315 bt_clear_frame_reg(bt, bt->frame, reg);
3318 static inline void bt_set_frame_slot(struct backtrack_state *bt, u32 frame, u32 slot)
3320 bt->stack_masks[frame] |= 1ull << slot;
3323 static inline void bt_clear_frame_slot(struct backtrack_state *bt, u32 frame, u32 slot)
3325 bt->stack_masks[frame] &= ~(1ull << slot);
3328 static inline void bt_set_slot(struct backtrack_state *bt, u32 slot)
3330 bt_set_frame_slot(bt, bt->frame, slot);
3333 static inline void bt_clear_slot(struct backtrack_state *bt, u32 slot)
3335 bt_clear_frame_slot(bt, bt->frame, slot);
3338 static inline u32 bt_frame_reg_mask(struct backtrack_state *bt, u32 frame)
3340 return bt->reg_masks[frame];
3343 static inline u32 bt_reg_mask(struct backtrack_state *bt)
3345 return bt->reg_masks[bt->frame];
3348 static inline u64 bt_frame_stack_mask(struct backtrack_state *bt, u32 frame)
3350 return bt->stack_masks[frame];
3353 static inline u64 bt_stack_mask(struct backtrack_state *bt)
3355 return bt->stack_masks[bt->frame];
3358 static inline bool bt_is_reg_set(struct backtrack_state *bt, u32 reg)
3360 return bt->reg_masks[bt->frame] & (1 << reg);
3363 static inline bool bt_is_slot_set(struct backtrack_state *bt, u32 slot)
3365 return bt->stack_masks[bt->frame] & (1ull << slot);
3368 /* format registers bitmask, e.g., "r0,r2,r4" for 0x15 mask */
3369 static void fmt_reg_mask(char *buf, ssize_t buf_sz, u32 reg_mask)
3371 DECLARE_BITMAP(mask, 64);
3377 bitmap_from_u64(mask, reg_mask);
3378 for_each_set_bit(i, mask, 32) {
3379 n = snprintf(buf, buf_sz, "%sr%d", first ? "" : ",", i);
3387 /* format stack slots bitmask, e.g., "-8,-24,-40" for 0x15 mask */
3388 static void fmt_stack_mask(char *buf, ssize_t buf_sz, u64 stack_mask)
3390 DECLARE_BITMAP(mask, 64);
3396 bitmap_from_u64(mask, stack_mask);
3397 for_each_set_bit(i, mask, 64) {
3398 n = snprintf(buf, buf_sz, "%s%d", first ? "" : ",", -(i + 1) * 8);
3407 /* For given verifier state backtrack_insn() is called from the last insn to
3408 * the first insn. Its purpose is to compute a bitmask of registers and
3409 * stack slots that needs precision in the parent verifier state.
3411 * @idx is an index of the instruction we are currently processing;
3412 * @subseq_idx is an index of the subsequent instruction that:
3413 * - *would be* executed next, if jump history is viewed in forward order;
3414 * - *was* processed previously during backtracking.
3416 static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx,
3417 struct backtrack_state *bt)
3419 const struct bpf_insn_cbs cbs = {
3420 .cb_call = disasm_kfunc_name,
3421 .cb_print = verbose,
3422 .private_data = env,
3424 struct bpf_insn *insn = env->prog->insnsi + idx;
3425 u8 class = BPF_CLASS(insn->code);
3426 u8 opcode = BPF_OP(insn->code);
3427 u8 mode = BPF_MODE(insn->code);
3428 u32 dreg = insn->dst_reg;
3429 u32 sreg = insn->src_reg;
3432 if (insn->code == 0)
3434 if (env->log.level & BPF_LOG_LEVEL2) {
3435 fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_reg_mask(bt));
3436 verbose(env, "mark_precise: frame%d: regs=%s ",
3437 bt->frame, env->tmp_str_buf);
3438 fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_stack_mask(bt));
3439 verbose(env, "stack=%s before ", env->tmp_str_buf);
3440 verbose(env, "%d: ", idx);
3441 print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
3444 if (class == BPF_ALU || class == BPF_ALU64) {
3445 if (!bt_is_reg_set(bt, dreg))
3447 if (opcode == BPF_END || opcode == BPF_NEG) {
3448 /* sreg is reserved and unused
3449 * dreg still need precision before this insn
3452 } else if (opcode == BPF_MOV) {
3453 if (BPF_SRC(insn->code) == BPF_X) {
3454 /* dreg = sreg or dreg = (s8, s16, s32)sreg
3455 * dreg needs precision after this insn
3456 * sreg needs precision before this insn
3458 bt_clear_reg(bt, dreg);
3459 bt_set_reg(bt, sreg);
3462 * dreg needs precision after this insn.
3463 * Corresponding register is already marked
3464 * as precise=true in this verifier state.
3465 * No further markings in parent are necessary
3467 bt_clear_reg(bt, dreg);
3470 if (BPF_SRC(insn->code) == BPF_X) {
3472 * both dreg and sreg need precision
3475 bt_set_reg(bt, sreg);
3477 * dreg still needs precision before this insn
3480 } else if (class == BPF_LDX) {
3481 if (!bt_is_reg_set(bt, dreg))
3483 bt_clear_reg(bt, dreg);
3485 /* scalars can only be spilled into stack w/o losing precision.
3486 * Load from any other memory can be zero extended.
3487 * The desire to keep that precision is already indicated
3488 * by 'precise' mark in corresponding register of this state.
3489 * No further tracking necessary.
3491 if (insn->src_reg != BPF_REG_FP)
3494 /* dreg = *(u64 *)[fp - off] was a fill from the stack.
3495 * that [fp - off] slot contains scalar that needs to be
3496 * tracked with precision
3498 spi = (-insn->off - 1) / BPF_REG_SIZE;
3500 verbose(env, "BUG spi %d\n", spi);
3501 WARN_ONCE(1, "verifier backtracking bug");
3504 bt_set_slot(bt, spi);
3505 } else if (class == BPF_STX || class == BPF_ST) {
3506 if (bt_is_reg_set(bt, dreg))
3507 /* stx & st shouldn't be using _scalar_ dst_reg
3508 * to access memory. It means backtracking
3509 * encountered a case of pointer subtraction.
3512 /* scalars can only be spilled into stack */
3513 if (insn->dst_reg != BPF_REG_FP)
3515 spi = (-insn->off - 1) / BPF_REG_SIZE;
3517 verbose(env, "BUG spi %d\n", spi);
3518 WARN_ONCE(1, "verifier backtracking bug");
3521 if (!bt_is_slot_set(bt, spi))
3523 bt_clear_slot(bt, spi);
3524 if (class == BPF_STX)
3525 bt_set_reg(bt, sreg);
3526 } else if (class == BPF_JMP || class == BPF_JMP32) {
3527 if (bpf_pseudo_call(insn)) {
3528 int subprog_insn_idx, subprog;
3530 subprog_insn_idx = idx + insn->imm + 1;
3531 subprog = find_subprog(env, subprog_insn_idx);
3535 if (subprog_is_global(env, subprog)) {
3536 /* check that jump history doesn't have any
3537 * extra instructions from subprog; the next
3538 * instruction after call to global subprog
3539 * should be literally next instruction in
3542 WARN_ONCE(idx + 1 != subseq_idx, "verifier backtracking bug");
3543 /* r1-r5 are invalidated after subprog call,
3544 * so for global func call it shouldn't be set
3547 if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
3548 verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
3549 WARN_ONCE(1, "verifier backtracking bug");
3552 /* global subprog always sets R0 */
3553 bt_clear_reg(bt, BPF_REG_0);
3556 /* static subprog call instruction, which
3557 * means that we are exiting current subprog,
3558 * so only r1-r5 could be still requested as
3559 * precise, r0 and r6-r10 or any stack slot in
3560 * the current frame should be zero by now
3562 if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
3563 verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
3564 WARN_ONCE(1, "verifier backtracking bug");
3567 /* we don't track register spills perfectly,
3568 * so fallback to force-precise instead of failing */
3569 if (bt_stack_mask(bt) != 0)
3571 /* propagate r1-r5 to the caller */
3572 for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
3573 if (bt_is_reg_set(bt, i)) {
3574 bt_clear_reg(bt, i);
3575 bt_set_frame_reg(bt, bt->frame - 1, i);
3578 if (bt_subprog_exit(bt))
3582 } else if ((bpf_helper_call(insn) &&
3583 is_callback_calling_function(insn->imm) &&
3584 !is_async_callback_calling_function(insn->imm)) ||
3585 (bpf_pseudo_kfunc_call(insn) && is_callback_calling_kfunc(insn->imm))) {
3586 /* callback-calling helper or kfunc call, which means
3587 * we are exiting from subprog, but unlike the subprog
3588 * call handling above, we shouldn't propagate
3589 * precision of r1-r5 (if any requested), as they are
3590 * not actually arguments passed directly to callback
3593 if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
3594 verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
3595 WARN_ONCE(1, "verifier backtracking bug");
3598 if (bt_stack_mask(bt) != 0)
3600 /* clear r1-r5 in callback subprog's mask */
3601 for (i = BPF_REG_1; i <= BPF_REG_5; i++)
3602 bt_clear_reg(bt, i);
3603 if (bt_subprog_exit(bt))
3606 } else if (opcode == BPF_CALL) {
3607 /* kfunc with imm==0 is invalid and fixup_kfunc_call will
3608 * catch this error later. Make backtracking conservative
3611 if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && insn->imm == 0)
3613 /* regular helper call sets R0 */
3614 bt_clear_reg(bt, BPF_REG_0);
3615 if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
3616 /* if backtracing was looking for registers R1-R5
3617 * they should have been found already.
3619 verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
3620 WARN_ONCE(1, "verifier backtracking bug");
3623 } else if (opcode == BPF_EXIT) {
3626 if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
3627 /* if backtracing was looking for registers R1-R5
3628 * they should have been found already.
3630 verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
3631 WARN_ONCE(1, "verifier backtracking bug");
3635 /* BPF_EXIT in subprog or callback always returns
3636 * right after the call instruction, so by checking
3637 * whether the instruction at subseq_idx-1 is subprog
3638 * call or not we can distinguish actual exit from
3639 * *subprog* from exit from *callback*. In the former
3640 * case, we need to propagate r0 precision, if
3641 * necessary. In the former we never do that.
3643 r0_precise = subseq_idx - 1 >= 0 &&
3644 bpf_pseudo_call(&env->prog->insnsi[subseq_idx - 1]) &&
3645 bt_is_reg_set(bt, BPF_REG_0);
3647 bt_clear_reg(bt, BPF_REG_0);
3648 if (bt_subprog_enter(bt))
3652 bt_set_reg(bt, BPF_REG_0);
3653 /* r6-r9 and stack slots will stay set in caller frame
3654 * bitmasks until we return back from callee(s)
3657 } else if (BPF_SRC(insn->code) == BPF_X) {
3658 if (!bt_is_reg_set(bt, dreg) && !bt_is_reg_set(bt, sreg))
3661 * Both dreg and sreg need precision before
3662 * this insn. If only sreg was marked precise
3663 * before it would be equally necessary to
3664 * propagate it to dreg.
3666 bt_set_reg(bt, dreg);
3667 bt_set_reg(bt, sreg);
3668 /* else dreg <cond> K
3669 * Only dreg still needs precision before
3670 * this insn, so for the K-based conditional
3671 * there is nothing new to be marked.
3674 } else if (class == BPF_LD) {
3675 if (!bt_is_reg_set(bt, dreg))
3677 bt_clear_reg(bt, dreg);
3678 /* It's ld_imm64 or ld_abs or ld_ind.
3679 * For ld_imm64 no further tracking of precision
3680 * into parent is necessary
3682 if (mode == BPF_IND || mode == BPF_ABS)
3683 /* to be analyzed */
3689 /* the scalar precision tracking algorithm:
3690 * . at the start all registers have precise=false.
3691 * . scalar ranges are tracked as normal through alu and jmp insns.
3692 * . once precise value of the scalar register is used in:
3693 * . ptr + scalar alu
3694 * . if (scalar cond K|scalar)
3695 * . helper_call(.., scalar, ...) where ARG_CONST is expected
3696 * backtrack through the verifier states and mark all registers and
3697 * stack slots with spilled constants that these scalar regisers
3698 * should be precise.
3699 * . during state pruning two registers (or spilled stack slots)
3700 * are equivalent if both are not precise.
3702 * Note the verifier cannot simply walk register parentage chain,
3703 * since many different registers and stack slots could have been
3704 * used to compute single precise scalar.
3706 * The approach of starting with precise=true for all registers and then
3707 * backtrack to mark a register as not precise when the verifier detects
3708 * that program doesn't care about specific value (e.g., when helper
3709 * takes register as ARG_ANYTHING parameter) is not safe.
3711 * It's ok to walk single parentage chain of the verifier states.
3712 * It's possible that this backtracking will go all the way till 1st insn.
3713 * All other branches will be explored for needing precision later.
3715 * The backtracking needs to deal with cases like:
3716 * R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
3719 * if r5 > 0x79f goto pc+7
3720 * R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
3723 * call bpf_perf_event_output#25
3724 * where .arg5_type = ARG_CONST_SIZE_OR_ZERO
3728 * call foo // uses callee's r6 inside to compute r0
3732 * to track above reg_mask/stack_mask needs to be independent for each frame.
3734 * Also if parent's curframe > frame where backtracking started,
3735 * the verifier need to mark registers in both frames, otherwise callees
3736 * may incorrectly prune callers. This is similar to
3737 * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
3739 * For now backtracking falls back into conservative marking.
3741 static void mark_all_scalars_precise(struct bpf_verifier_env *env,
3742 struct bpf_verifier_state *st)
3744 struct bpf_func_state *func;
3745 struct bpf_reg_state *reg;
3748 if (env->log.level & BPF_LOG_LEVEL2) {
3749 verbose(env, "mark_precise: frame%d: falling back to forcing all scalars precise\n",
3753 /* big hammer: mark all scalars precise in this path.
3754 * pop_stack may still get !precise scalars.
3755 * We also skip current state and go straight to first parent state,
3756 * because precision markings in current non-checkpointed state are
3757 * not needed. See why in the comment in __mark_chain_precision below.
3759 for (st = st->parent; st; st = st->parent) {
3760 for (i = 0; i <= st->curframe; i++) {
3761 func = st->frame[i];
3762 for (j = 0; j < BPF_REG_FP; j++) {
3763 reg = &func->regs[j];
3764 if (reg->type != SCALAR_VALUE || reg->precise)
3766 reg->precise = true;
3767 if (env->log.level & BPF_LOG_LEVEL2) {
3768 verbose(env, "force_precise: frame%d: forcing r%d to be precise\n",
3772 for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
3773 if (!is_spilled_reg(&func->stack[j]))
3775 reg = &func->stack[j].spilled_ptr;
3776 if (reg->type != SCALAR_VALUE || reg->precise)
3778 reg->precise = true;
3779 if (env->log.level & BPF_LOG_LEVEL2) {
3780 verbose(env, "force_precise: frame%d: forcing fp%d to be precise\n",
3788 static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
3790 struct bpf_func_state *func;
3791 struct bpf_reg_state *reg;
3794 for (i = 0; i <= st->curframe; i++) {
3795 func = st->frame[i];
3796 for (j = 0; j < BPF_REG_FP; j++) {
3797 reg = &func->regs[j];
3798 if (reg->type != SCALAR_VALUE)
3800 reg->precise = false;
3802 for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
3803 if (!is_spilled_reg(&func->stack[j]))
3805 reg = &func->stack[j].spilled_ptr;
3806 if (reg->type != SCALAR_VALUE)
3808 reg->precise = false;
3813 static bool idset_contains(struct bpf_idset *s, u32 id)
3817 for (i = 0; i < s->count; ++i)
3818 if (s->ids[i] == id)
3824 static int idset_push(struct bpf_idset *s, u32 id)
3826 if (WARN_ON_ONCE(s->count >= ARRAY_SIZE(s->ids)))
3828 s->ids[s->count++] = id;
3832 static void idset_reset(struct bpf_idset *s)
3837 /* Collect a set of IDs for all registers currently marked as precise in env->bt.
3838 * Mark all registers with these IDs as precise.
3840 static int mark_precise_scalar_ids(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
3842 struct bpf_idset *precise_ids = &env->idset_scratch;
3843 struct backtrack_state *bt = &env->bt;
3844 struct bpf_func_state *func;
3845 struct bpf_reg_state *reg;
3846 DECLARE_BITMAP(mask, 64);
3849 idset_reset(precise_ids);
3851 for (fr = bt->frame; fr >= 0; fr--) {
3852 func = st->frame[fr];
3854 bitmap_from_u64(mask, bt_frame_reg_mask(bt, fr));
3855 for_each_set_bit(i, mask, 32) {
3856 reg = &func->regs[i];
3857 if (!reg->id || reg->type != SCALAR_VALUE)
3859 if (idset_push(precise_ids, reg->id))
3863 bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr));
3864 for_each_set_bit(i, mask, 64) {
3865 if (i >= func->allocated_stack / BPF_REG_SIZE)
3867 if (!is_spilled_scalar_reg(&func->stack[i]))
3869 reg = &func->stack[i].spilled_ptr;
3872 if (idset_push(precise_ids, reg->id))
3877 for (fr = 0; fr <= st->curframe; ++fr) {
3878 func = st->frame[fr];
3880 for (i = BPF_REG_0; i < BPF_REG_10; ++i) {
3881 reg = &func->regs[i];
3884 if (!idset_contains(precise_ids, reg->id))
3886 bt_set_frame_reg(bt, fr, i);
3888 for (i = 0; i < func->allocated_stack / BPF_REG_SIZE; ++i) {
3889 if (!is_spilled_scalar_reg(&func->stack[i]))
3891 reg = &func->stack[i].spilled_ptr;
3894 if (!idset_contains(precise_ids, reg->id))
3896 bt_set_frame_slot(bt, fr, i);
3904 * __mark_chain_precision() backtracks BPF program instruction sequence and
3905 * chain of verifier states making sure that register *regno* (if regno >= 0)
3906 * and/or stack slot *spi* (if spi >= 0) are marked as precisely tracked
3907 * SCALARS, as well as any other registers and slots that contribute to
3908 * a tracked state of given registers/stack slots, depending on specific BPF
3909 * assembly instructions (see backtrack_insns() for exact instruction handling
3910 * logic). This backtracking relies on recorded jmp_history and is able to
3911 * traverse entire chain of parent states. This process ends only when all the
3912 * necessary registers/slots and their transitive dependencies are marked as
3915 * One important and subtle aspect is that precise marks *do not matter* in
3916 * the currently verified state (current state). It is important to understand
3917 * why this is the case.
3919 * First, note that current state is the state that is not yet "checkpointed",
3920 * i.e., it is not yet put into env->explored_states, and it has no children
3921 * states as well. It's ephemeral, and can end up either a) being discarded if
3922 * compatible explored state is found at some point or BPF_EXIT instruction is
3923 * reached or b) checkpointed and put into env->explored_states, branching out
3924 * into one or more children states.
3926 * In the former case, precise markings in current state are completely
3927 * ignored by state comparison code (see regsafe() for details). Only
3928 * checkpointed ("old") state precise markings are important, and if old
3929 * state's register/slot is precise, regsafe() assumes current state's
3930 * register/slot as precise and checks value ranges exactly and precisely. If
3931 * states turn out to be compatible, current state's necessary precise
3932 * markings and any required parent states' precise markings are enforced
3933 * after the fact with propagate_precision() logic, after the fact. But it's
3934 * important to realize that in this case, even after marking current state
3935 * registers/slots as precise, we immediately discard current state. So what
3936 * actually matters is any of the precise markings propagated into current
3937 * state's parent states, which are always checkpointed (due to b) case above).
3938 * As such, for scenario a) it doesn't matter if current state has precise
3939 * markings set or not.
3941 * Now, for the scenario b), checkpointing and forking into child(ren)
3942 * state(s). Note that before current state gets to checkpointing step, any
3943 * processed instruction always assumes precise SCALAR register/slot
3944 * knowledge: if precise value or range is useful to prune jump branch, BPF
3945 * verifier takes this opportunity enthusiastically. Similarly, when
3946 * register's value is used to calculate offset or memory address, exact
3947 * knowledge of SCALAR range is assumed, checked, and enforced. So, similar to
3948 * what we mentioned above about state comparison ignoring precise markings
3949 * during state comparison, BPF verifier ignores and also assumes precise
3950 * markings *at will* during instruction verification process. But as verifier
3951 * assumes precision, it also propagates any precision dependencies across
3952 * parent states, which are not yet finalized, so can be further restricted
3953 * based on new knowledge gained from restrictions enforced by their children
3954 * states. This is so that once those parent states are finalized, i.e., when
3955 * they have no more active children state, state comparison logic in
3956 * is_state_visited() would enforce strict and precise SCALAR ranges, if
3957 * required for correctness.
3959 * To build a bit more intuition, note also that once a state is checkpointed,
3960 * the path we took to get to that state is not important. This is crucial
3961 * property for state pruning. When state is checkpointed and finalized at
3962 * some instruction index, it can be correctly and safely used to "short
3963 * circuit" any *compatible* state that reaches exactly the same instruction
3964 * index. I.e., if we jumped to that instruction from a completely different
3965 * code path than original finalized state was derived from, it doesn't
3966 * matter, current state can be discarded because from that instruction
3967 * forward having a compatible state will ensure we will safely reach the
3968 * exit. States describe preconditions for further exploration, but completely
3969 * forget the history of how we got here.
3971 * This also means that even if we needed precise SCALAR range to get to
3972 * finalized state, but from that point forward *that same* SCALAR register is
3973 * never used in a precise context (i.e., it's precise value is not needed for
3974 * correctness), it's correct and safe to mark such register as "imprecise"
3975 * (i.e., precise marking set to false). This is what we rely on when we do
3976 * not set precise marking in current state. If no child state requires
3977 * precision for any given SCALAR register, it's safe to dictate that it can
3978 * be imprecise. If any child state does require this register to be precise,
3979 * we'll mark it precise later retroactively during precise markings
3980 * propagation from child state to parent states.
3982 * Skipping precise marking setting in current state is a mild version of
3983 * relying on the above observation. But we can utilize this property even
3984 * more aggressively by proactively forgetting any precise marking in the
3985 * current state (which we inherited from the parent state), right before we
3986 * checkpoint it and branch off into new child state. This is done by
3987 * mark_all_scalars_imprecise() to hopefully get more permissive and generic
3988 * finalized states which help in short circuiting more future states.
3990 static int __mark_chain_precision(struct bpf_verifier_env *env, int regno)
3992 struct backtrack_state *bt = &env->bt;
3993 struct bpf_verifier_state *st = env->cur_state;
3994 int first_idx = st->first_insn_idx;
3995 int last_idx = env->insn_idx;
3996 int subseq_idx = -1;
3997 struct bpf_func_state *func;
3998 struct bpf_reg_state *reg;
3999 bool skip_first = true;
4002 if (!env->bpf_capable)
4005 /* set frame number from which we are starting to backtrack */
4006 bt_init(bt, env->cur_state->curframe);
4008 /* Do sanity checks against current state of register and/or stack
4009 * slot, but don't set precise flag in current state, as precision
4010 * tracking in the current state is unnecessary.
4012 func = st->frame[bt->frame];
4014 reg = &func->regs[regno];
4015 if (reg->type != SCALAR_VALUE) {
4016 WARN_ONCE(1, "backtracing misuse");
4019 bt_set_reg(bt, regno);
4026 DECLARE_BITMAP(mask, 64);
4027 u32 history = st->jmp_history_cnt;
4029 if (env->log.level & BPF_LOG_LEVEL2) {
4030 verbose(env, "mark_precise: frame%d: last_idx %d first_idx %d subseq_idx %d \n",
4031 bt->frame, last_idx, first_idx, subseq_idx);
4034 /* If some register with scalar ID is marked as precise,
4035 * make sure that all registers sharing this ID are also precise.
4036 * This is needed to estimate effect of find_equal_scalars().
4037 * Do this at the last instruction of each state,
4038 * bpf_reg_state::id fields are valid for these instructions.
4040 * Allows to track precision in situation like below:
4042 * r2 = unknown value
4046 * r1 = r2 // r1 and r2 now share the same ID
4048 * --- state #1 {r1.id = A, r2.id = A} ---
4050 * if (r2 > 10) goto exit; // find_equal_scalars() assigns range to r1
4052 * --- state #2 {r1.id = A, r2.id = A} ---
4054 * r3 += r1 // need to mark both r1 and r2
4056 if (mark_precise_scalar_ids(env, st))
4060 /* we are at the entry into subprog, which
4061 * is expected for global funcs, but only if
4062 * requested precise registers are R1-R5
4063 * (which are global func's input arguments)
4065 if (st->curframe == 0 &&
4066 st->frame[0]->subprogno > 0 &&
4067 st->frame[0]->callsite == BPF_MAIN_FUNC &&
4068 bt_stack_mask(bt) == 0 &&
4069 (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) == 0) {
4070 bitmap_from_u64(mask, bt_reg_mask(bt));
4071 for_each_set_bit(i, mask, 32) {
4072 reg = &st->frame[0]->regs[i];
4073 bt_clear_reg(bt, i);
4074 if (reg->type == SCALAR_VALUE)
4075 reg->precise = true;
4080 verbose(env, "BUG backtracking func entry subprog %d reg_mask %x stack_mask %llx\n",
4081 st->frame[0]->subprogno, bt_reg_mask(bt), bt_stack_mask(bt));
4082 WARN_ONCE(1, "verifier backtracking bug");
4086 for (i = last_idx;;) {
4091 err = backtrack_insn(env, i, subseq_idx, bt);
4093 if (err == -ENOTSUPP) {
4094 mark_all_scalars_precise(env, env->cur_state);
4101 /* Found assignment(s) into tracked register in this state.
4102 * Since this state is already marked, just return.
4103 * Nothing to be tracked further in the parent state.
4107 i = get_prev_insn_idx(st, i, &history);
4110 if (i >= env->prog->len) {
4111 /* This can happen if backtracking reached insn 0
4112 * and there are still reg_mask or stack_mask
4114 * It means the backtracking missed the spot where
4115 * particular register was initialized with a constant.
4117 verbose(env, "BUG backtracking idx %d\n", i);
4118 WARN_ONCE(1, "verifier backtracking bug");
4126 for (fr = bt->frame; fr >= 0; fr--) {
4127 func = st->frame[fr];
4128 bitmap_from_u64(mask, bt_frame_reg_mask(bt, fr));
4129 for_each_set_bit(i, mask, 32) {
4130 reg = &func->regs[i];
4131 if (reg->type != SCALAR_VALUE) {
4132 bt_clear_frame_reg(bt, fr, i);
4136 bt_clear_frame_reg(bt, fr, i);
4138 reg->precise = true;
4141 bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr));
4142 for_each_set_bit(i, mask, 64) {
4143 if (i >= func->allocated_stack / BPF_REG_SIZE) {
4144 /* the sequence of instructions:
4146 * 3: (7b) *(u64 *)(r3 -8) = r0
4147 * 4: (79) r4 = *(u64 *)(r10 -8)
4148 * doesn't contain jmps. It's backtracked
4149 * as a single block.
4150 * During backtracking insn 3 is not recognized as
4151 * stack access, so at the end of backtracking
4152 * stack slot fp-8 is still marked in stack_mask.
4153 * However the parent state may not have accessed
4154 * fp-8 and it's "unallocated" stack space.
4155 * In such case fallback to conservative.
4157 mark_all_scalars_precise(env, env->cur_state);
4162 if (!is_spilled_scalar_reg(&func->stack[i])) {
4163 bt_clear_frame_slot(bt, fr, i);
4166 reg = &func->stack[i].spilled_ptr;
4168 bt_clear_frame_slot(bt, fr, i);
4170 reg->precise = true;
4172 if (env->log.level & BPF_LOG_LEVEL2) {
4173 fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN,
4174 bt_frame_reg_mask(bt, fr));
4175 verbose(env, "mark_precise: frame%d: parent state regs=%s ",
4176 fr, env->tmp_str_buf);
4177 fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN,
4178 bt_frame_stack_mask(bt, fr));
4179 verbose(env, "stack=%s: ", env->tmp_str_buf);
4180 print_verifier_state(env, func, true);
4187 subseq_idx = first_idx;
4188 last_idx = st->last_insn_idx;
4189 first_idx = st->first_insn_idx;
4192 /* if we still have requested precise regs or slots, we missed
4193 * something (e.g., stack access through non-r10 register), so
4194 * fallback to marking all precise
4196 if (!bt_empty(bt)) {
4197 mark_all_scalars_precise(env, env->cur_state);
4204 int mark_chain_precision(struct bpf_verifier_env *env, int regno)
4206 return __mark_chain_precision(env, regno);
4209 /* mark_chain_precision_batch() assumes that env->bt is set in the caller to
4210 * desired reg and stack masks across all relevant frames
4212 static int mark_chain_precision_batch(struct bpf_verifier_env *env)
4214 return __mark_chain_precision(env, -1);
4217 static bool is_spillable_regtype(enum bpf_reg_type type)
4219 switch (base_type(type)) {
4220 case PTR_TO_MAP_VALUE:
4224 case PTR_TO_PACKET_META:
4225 case PTR_TO_PACKET_END:
4226 case PTR_TO_FLOW_KEYS:
4227 case CONST_PTR_TO_MAP:
4229 case PTR_TO_SOCK_COMMON:
4230 case PTR_TO_TCP_SOCK:
4231 case PTR_TO_XDP_SOCK:
4236 case PTR_TO_MAP_KEY:
4243 /* Does this register contain a constant zero? */
4244 static bool register_is_null(struct bpf_reg_state *reg)
4246 return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
4249 static bool register_is_const(struct bpf_reg_state *reg)
4251 return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
4254 static bool __is_scalar_unbounded(struct bpf_reg_state *reg)
4256 return tnum_is_unknown(reg->var_off) &&
4257 reg->smin_value == S64_MIN && reg->smax_value == S64_MAX &&
4258 reg->umin_value == 0 && reg->umax_value == U64_MAX &&
4259 reg->s32_min_value == S32_MIN && reg->s32_max_value == S32_MAX &&
4260 reg->u32_min_value == 0 && reg->u32_max_value == U32_MAX;
4263 static bool register_is_bounded(struct bpf_reg_state *reg)
4265 return reg->type == SCALAR_VALUE && !__is_scalar_unbounded(reg);
4268 static bool __is_pointer_value(bool allow_ptr_leaks,
4269 const struct bpf_reg_state *reg)
4271 if (allow_ptr_leaks)
4274 return reg->type != SCALAR_VALUE;
4277 /* Copy src state preserving dst->parent and dst->live fields */
4278 static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
4280 struct bpf_reg_state *parent = dst->parent;
4281 enum bpf_reg_liveness live = dst->live;
4284 dst->parent = parent;
4288 static void save_register_state(struct bpf_func_state *state,
4289 int spi, struct bpf_reg_state *reg,
4294 copy_register_state(&state->stack[spi].spilled_ptr, reg);
4295 if (size == BPF_REG_SIZE)
4296 state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
4298 for (i = BPF_REG_SIZE; i > BPF_REG_SIZE - size; i--)
4299 state->stack[spi].slot_type[i - 1] = STACK_SPILL;
4301 /* size < 8 bytes spill */
4303 scrub_spilled_slot(&state->stack[spi].slot_type[i - 1]);
4306 static bool is_bpf_st_mem(struct bpf_insn *insn)
4308 return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
4311 /* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
4312 * stack boundary and alignment are checked in check_mem_access()
4314 static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
4315 /* stack frame we're writing to */
4316 struct bpf_func_state *state,
4317 int off, int size, int value_regno,
4320 struct bpf_func_state *cur; /* state of the current function */
4321 int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
4322 struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
4323 struct bpf_reg_state *reg = NULL;
4324 u32 dst_reg = insn->dst_reg;
4326 err = grow_stack_state(state, round_up(slot + 1, BPF_REG_SIZE));
4329 /* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
4330 * so it's aligned access and [off, off + size) are within stack limits
4332 if (!env->allow_ptr_leaks &&
4333 state->stack[spi].slot_type[0] == STACK_SPILL &&
4334 size != BPF_REG_SIZE) {
4335 verbose(env, "attempt to corrupt spilled pointer on stack\n");
4339 cur = env->cur_state->frame[env->cur_state->curframe];
4340 if (value_regno >= 0)
4341 reg = &cur->regs[value_regno];
4342 if (!env->bypass_spec_v4) {
4343 bool sanitize = reg && is_spillable_regtype(reg->type);
4345 for (i = 0; i < size; i++) {
4346 u8 type = state->stack[spi].slot_type[i];
4348 if (type != STACK_MISC && type != STACK_ZERO) {
4355 env->insn_aux_data[insn_idx].sanitize_stack_spill = true;
4358 err = destroy_if_dynptr_stack_slot(env, state, spi);
4362 mark_stack_slot_scratched(env, spi);
4363 if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) &&
4364 !register_is_null(reg) && env->bpf_capable) {
4365 if (dst_reg != BPF_REG_FP) {
4366 /* The backtracking logic can only recognize explicit
4367 * stack slot address like [fp - 8]. Other spill of
4368 * scalar via different register has to be conservative.
4369 * Backtrack from here and mark all registers as precise
4370 * that contributed into 'reg' being a constant.
4372 err = mark_chain_precision(env, value_regno);
4376 save_register_state(state, spi, reg, size);
4377 /* Break the relation on a narrowing spill. */
4378 if (fls64(reg->umax_value) > BITS_PER_BYTE * size)
4379 state->stack[spi].spilled_ptr.id = 0;
4380 } else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
4381 insn->imm != 0 && env->bpf_capable) {
4382 struct bpf_reg_state fake_reg = {};
4384 __mark_reg_known(&fake_reg, insn->imm);
4385 fake_reg.type = SCALAR_VALUE;
4386 save_register_state(state, spi, &fake_reg, size);
4387 } else if (reg && is_spillable_regtype(reg->type)) {
4388 /* register containing pointer is being spilled into stack */
4389 if (size != BPF_REG_SIZE) {
4390 verbose_linfo(env, insn_idx, "; ");
4391 verbose(env, "invalid size of register spill\n");
4394 if (state != cur && reg->type == PTR_TO_STACK) {
4395 verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
4398 save_register_state(state, spi, reg, size);
4400 u8 type = STACK_MISC;
4402 /* regular write of data into stack destroys any spilled ptr */
4403 state->stack[spi].spilled_ptr.type = NOT_INIT;
4404 /* Mark slots as STACK_MISC if they belonged to spilled ptr/dynptr/iter. */
4405 if (is_stack_slot_special(&state->stack[spi]))
4406 for (i = 0; i < BPF_REG_SIZE; i++)
4407 scrub_spilled_slot(&state->stack[spi].slot_type[i]);
4409 /* only mark the slot as written if all 8 bytes were written
4410 * otherwise read propagation may incorrectly stop too soon
4411 * when stack slots are partially written.
4412 * This heuristic means that read propagation will be
4413 * conservative, since it will add reg_live_read marks
4414 * to stack slots all the way to first state when programs
4415 * writes+reads less than 8 bytes
4417 if (size == BPF_REG_SIZE)
4418 state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
4420 /* when we zero initialize stack slots mark them as such */
4421 if ((reg && register_is_null(reg)) ||
4422 (!reg && is_bpf_st_mem(insn) && insn->imm == 0)) {
4423 /* backtracking doesn't work for STACK_ZERO yet. */
4424 err = mark_chain_precision(env, value_regno);
4430 /* Mark slots affected by this stack write. */
4431 for (i = 0; i < size; i++)
4432 state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
4438 /* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is
4439 * known to contain a variable offset.
4440 * This function checks whether the write is permitted and conservatively
4441 * tracks the effects of the write, considering that each stack slot in the
4442 * dynamic range is potentially written to.
4444 * 'off' includes 'regno->off'.
4445 * 'value_regno' can be -1, meaning that an unknown value is being written to
4448 * Spilled pointers in range are not marked as written because we don't know
4449 * what's going to be actually written. This means that read propagation for
4450 * future reads cannot be terminated by this write.
4452 * For privileged programs, uninitialized stack slots are considered
4453 * initialized by this write (even though we don't know exactly what offsets
4454 * are going to be written to). The idea is that we don't want the verifier to
4455 * reject future reads that access slots written to through variable offsets.
4457 static int check_stack_write_var_off(struct bpf_verifier_env *env,
4458 /* func where register points to */
4459 struct bpf_func_state *state,
4460 int ptr_regno, int off, int size,
4461 int value_regno, int insn_idx)
4463 struct bpf_func_state *cur; /* state of the current function */
4464 int min_off, max_off;
4466 struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL;
4467 struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
4468 bool writing_zero = false;
4469 /* set if the fact that we're writing a zero is used to let any
4470 * stack slots remain STACK_ZERO
4472 bool zero_used = false;
4474 cur = env->cur_state->frame[env->cur_state->curframe];
4475 ptr_reg = &cur->regs[ptr_regno];
4476 min_off = ptr_reg->smin_value + off;
4477 max_off = ptr_reg->smax_value + off + size;
4478 if (value_regno >= 0)
4479 value_reg = &cur->regs[value_regno];
4480 if ((value_reg && register_is_null(value_reg)) ||
4481 (!value_reg && is_bpf_st_mem(insn) && insn->imm == 0))
4482 writing_zero = true;
4484 err = grow_stack_state(state, round_up(-min_off, BPF_REG_SIZE));
4488 for (i = min_off; i < max_off; i++) {
4492 err = destroy_if_dynptr_stack_slot(env, state, spi);
4497 /* Variable offset writes destroy any spilled pointers in range. */
4498 for (i = min_off; i < max_off; i++) {
4499 u8 new_type, *stype;
4503 spi = slot / BPF_REG_SIZE;
4504 stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
4505 mark_stack_slot_scratched(env, spi);
4507 if (!env->allow_ptr_leaks && *stype != STACK_MISC && *stype != STACK_ZERO) {
4508 /* Reject the write if range we may write to has not
4509 * been initialized beforehand. If we didn't reject
4510 * here, the ptr status would be erased below (even
4511 * though not all slots are actually overwritten),
4512 * possibly opening the door to leaks.
4514 * We do however catch STACK_INVALID case below, and
4515 * only allow reading possibly uninitialized memory
4516 * later for CAP_PERFMON, as the write may not happen to
4519 verbose(env, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d",
4524 /* Erase all spilled pointers. */
4525 state->stack[spi].spilled_ptr.type = NOT_INIT;
4527 /* Update the slot type. */
4528 new_type = STACK_MISC;
4529 if (writing_zero && *stype == STACK_ZERO) {
4530 new_type = STACK_ZERO;
4533 /* If the slot is STACK_INVALID, we check whether it's OK to
4534 * pretend that it will be initialized by this write. The slot
4535 * might not actually be written to, and so if we mark it as
4536 * initialized future reads might leak uninitialized memory.
4537 * For privileged programs, we will accept such reads to slots
4538 * that may or may not be written because, if we're reject
4539 * them, the error would be too confusing.
4541 if (*stype == STACK_INVALID && !env->allow_uninit_stack) {
4542 verbose(env, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d",
4549 /* backtracking doesn't work for STACK_ZERO yet. */
4550 err = mark_chain_precision(env, value_regno);
4557 /* When register 'dst_regno' is assigned some values from stack[min_off,
4558 * max_off), we set the register's type according to the types of the
4559 * respective stack slots. If all the stack values are known to be zeros, then
4560 * so is the destination reg. Otherwise, the register is considered to be
4561 * SCALAR. This function does not deal with register filling; the caller must
4562 * ensure that all spilled registers in the stack range have been marked as
4565 static void mark_reg_stack_read(struct bpf_verifier_env *env,
4566 /* func where src register points to */
4567 struct bpf_func_state *ptr_state,
4568 int min_off, int max_off, int dst_regno)
4570 struct bpf_verifier_state *vstate = env->cur_state;
4571 struct bpf_func_state *state = vstate->frame[vstate->curframe];
4576 for (i = min_off; i < max_off; i++) {
4578 spi = slot / BPF_REG_SIZE;
4579 mark_stack_slot_scratched(env, spi);
4580 stype = ptr_state->stack[spi].slot_type;
4581 if (stype[slot % BPF_REG_SIZE] != STACK_ZERO)
4585 if (zeros == max_off - min_off) {
4586 /* any access_size read into register is zero extended,
4587 * so the whole register == const_zero
4589 __mark_reg_const_zero(&state->regs[dst_regno]);
4590 /* backtracking doesn't support STACK_ZERO yet,
4591 * so mark it precise here, so that later
4592 * backtracking can stop here.
4593 * Backtracking may not need this if this register
4594 * doesn't participate in pointer adjustment.
4595 * Forward propagation of precise flag is not
4596 * necessary either. This mark is only to stop
4597 * backtracking. Any register that contributed
4598 * to const 0 was marked precise before spill.
4600 state->regs[dst_regno].precise = true;
4602 /* have read misc data from the stack */
4603 mark_reg_unknown(env, state->regs, dst_regno);
4605 state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4608 /* Read the stack at 'off' and put the results into the register indicated by
4609 * 'dst_regno'. It handles reg filling if the addressed stack slot is a
4612 * 'dst_regno' can be -1, meaning that the read value is not going to a
4615 * The access is assumed to be within the current stack bounds.
4617 static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
4618 /* func where src register points to */
4619 struct bpf_func_state *reg_state,
4620 int off, int size, int dst_regno)
4622 struct bpf_verifier_state *vstate = env->cur_state;
4623 struct bpf_func_state *state = vstate->frame[vstate->curframe];
4624 int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
4625 struct bpf_reg_state *reg;
4628 stype = reg_state->stack[spi].slot_type;
4629 reg = ®_state->stack[spi].spilled_ptr;
4631 mark_stack_slot_scratched(env, spi);
4633 if (is_spilled_reg(®_state->stack[spi])) {
4636 for (i = BPF_REG_SIZE - 1; i > 0 && stype[i - 1] == STACK_SPILL; i--)
4639 if (size != BPF_REG_SIZE || spill_size != BPF_REG_SIZE) {
4640 if (reg->type != SCALAR_VALUE) {
4641 verbose_linfo(env, env->insn_idx, "; ");
4642 verbose(env, "invalid size of register fill\n");
4646 mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
4650 if (!(off % BPF_REG_SIZE) && size == spill_size) {
4651 /* The earlier check_reg_arg() has decided the
4652 * subreg_def for this insn. Save it first.
4654 s32 subreg_def = state->regs[dst_regno].subreg_def;
4656 copy_register_state(&state->regs[dst_regno], reg);
4657 state->regs[dst_regno].subreg_def = subreg_def;
4659 for (i = 0; i < size; i++) {
4660 type = stype[(slot - i) % BPF_REG_SIZE];
4661 if (type == STACK_SPILL)
4663 if (type == STACK_MISC)
4665 if (type == STACK_INVALID && env->allow_uninit_stack)
4667 verbose(env, "invalid read from stack off %d+%d size %d\n",
4671 mark_reg_unknown(env, state->regs, dst_regno);
4673 state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4677 if (dst_regno >= 0) {
4678 /* restore register state from stack */
4679 copy_register_state(&state->regs[dst_regno], reg);
4680 /* mark reg as written since spilled pointer state likely
4681 * has its liveness marks cleared by is_state_visited()
4682 * which resets stack/reg liveness for state transitions
4684 state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4685 } else if (__is_pointer_value(env->allow_ptr_leaks, reg)) {
4686 /* If dst_regno==-1, the caller is asking us whether
4687 * it is acceptable to use this value as a SCALAR_VALUE
4689 * We must not allow unprivileged callers to do that
4690 * with spilled pointers.
4692 verbose(env, "leaking pointer from stack off %d\n",
4696 mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
4698 for (i = 0; i < size; i++) {
4699 type = stype[(slot - i) % BPF_REG_SIZE];
4700 if (type == STACK_MISC)
4702 if (type == STACK_ZERO)
4704 if (type == STACK_INVALID && env->allow_uninit_stack)
4706 verbose(env, "invalid read from stack off %d+%d size %d\n",
4710 mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
4712 mark_reg_stack_read(env, reg_state, off, off + size, dst_regno);
4717 enum bpf_access_src {
4718 ACCESS_DIRECT = 1, /* the access is performed by an instruction */
4719 ACCESS_HELPER = 2, /* the access is performed by a helper */
4722 static int check_stack_range_initialized(struct bpf_verifier_env *env,
4723 int regno, int off, int access_size,
4724 bool zero_size_allowed,
4725 enum bpf_access_src type,
4726 struct bpf_call_arg_meta *meta);
4728 static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
4730 return cur_regs(env) + regno;
4733 /* Read the stack at 'ptr_regno + off' and put the result into the register
4735 * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'),
4736 * but not its variable offset.
4737 * 'size' is assumed to be <= reg size and the access is assumed to be aligned.
4739 * As opposed to check_stack_read_fixed_off, this function doesn't deal with
4740 * filling registers (i.e. reads of spilled register cannot be detected when
4741 * the offset is not fixed). We conservatively mark 'dst_regno' as containing
4742 * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable
4743 * offset; for a fixed offset check_stack_read_fixed_off should be used
4746 static int check_stack_read_var_off(struct bpf_verifier_env *env,
4747 int ptr_regno, int off, int size, int dst_regno)
4749 /* The state of the source register. */
4750 struct bpf_reg_state *reg = reg_state(env, ptr_regno);
4751 struct bpf_func_state *ptr_state = func(env, reg);
4753 int min_off, max_off;
4755 /* Note that we pass a NULL meta, so raw access will not be permitted.
4757 err = check_stack_range_initialized(env, ptr_regno, off, size,
4758 false, ACCESS_DIRECT, NULL);
4762 min_off = reg->smin_value + off;
4763 max_off = reg->smax_value + off;
4764 mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno);
4768 /* check_stack_read dispatches to check_stack_read_fixed_off or
4769 * check_stack_read_var_off.
4771 * The caller must ensure that the offset falls within the allocated stack
4774 * 'dst_regno' is a register which will receive the value from the stack. It
4775 * can be -1, meaning that the read value is not going to a register.
4777 static int check_stack_read(struct bpf_verifier_env *env,
4778 int ptr_regno, int off, int size,
4781 struct bpf_reg_state *reg = reg_state(env, ptr_regno);
4782 struct bpf_func_state *state = func(env, reg);
4784 /* Some accesses are only permitted with a static offset. */
4785 bool var_off = !tnum_is_const(reg->var_off);
4787 /* The offset is required to be static when reads don't go to a
4788 * register, in order to not leak pointers (see
4789 * check_stack_read_fixed_off).
4791 if (dst_regno < 0 && var_off) {
4794 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
4795 verbose(env, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n",
4799 /* Variable offset is prohibited for unprivileged mode for simplicity
4800 * since it requires corresponding support in Spectre masking for stack
4801 * ALU. See also retrieve_ptr_limit(). The check in
4802 * check_stack_access_for_ptr_arithmetic() called by
4803 * adjust_ptr_min_max_vals() prevents users from creating stack pointers
4804 * with variable offsets, therefore no check is required here. Further,
4805 * just checking it here would be insufficient as speculative stack
4806 * writes could still lead to unsafe speculative behaviour.
4809 off += reg->var_off.value;
4810 err = check_stack_read_fixed_off(env, state, off, size,
4813 /* Variable offset stack reads need more conservative handling
4814 * than fixed offset ones. Note that dst_regno >= 0 on this
4817 err = check_stack_read_var_off(env, ptr_regno, off, size,
4824 /* check_stack_write dispatches to check_stack_write_fixed_off or
4825 * check_stack_write_var_off.
4827 * 'ptr_regno' is the register used as a pointer into the stack.
4828 * 'off' includes 'ptr_regno->off', but not its variable offset (if any).
4829 * 'value_regno' is the register whose value we're writing to the stack. It can
4830 * be -1, meaning that we're not writing from a register.
4832 * The caller must ensure that the offset falls within the maximum stack size.
4834 static int check_stack_write(struct bpf_verifier_env *env,
4835 int ptr_regno, int off, int size,
4836 int value_regno, int insn_idx)
4838 struct bpf_reg_state *reg = reg_state(env, ptr_regno);
4839 struct bpf_func_state *state = func(env, reg);
4842 if (tnum_is_const(reg->var_off)) {
4843 off += reg->var_off.value;
4844 err = check_stack_write_fixed_off(env, state, off, size,
4845 value_regno, insn_idx);
4847 /* Variable offset stack reads need more conservative handling
4848 * than fixed offset ones.
4850 err = check_stack_write_var_off(env, state,
4851 ptr_regno, off, size,
4852 value_regno, insn_idx);
4857 static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
4858 int off, int size, enum bpf_access_type type)
4860 struct bpf_reg_state *regs = cur_regs(env);
4861 struct bpf_map *map = regs[regno].map_ptr;
4862 u32 cap = bpf_map_flags_to_cap(map);
4864 if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
4865 verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
4866 map->value_size, off, size);
4870 if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
4871 verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
4872 map->value_size, off, size);
4879 /* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
4880 static int __check_mem_access(struct bpf_verifier_env *env, int regno,
4881 int off, int size, u32 mem_size,
4882 bool zero_size_allowed)
4884 bool size_ok = size > 0 || (size == 0 && zero_size_allowed);
4885 struct bpf_reg_state *reg;
4887 if (off >= 0 && size_ok && (u64)off + size <= mem_size)
4890 reg = &cur_regs(env)[regno];
4891 switch (reg->type) {
4892 case PTR_TO_MAP_KEY:
4893 verbose(env, "invalid access to map key, key_size=%d off=%d size=%d\n",
4894 mem_size, off, size);
4896 case PTR_TO_MAP_VALUE:
4897 verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n",
4898 mem_size, off, size);
4901 case PTR_TO_PACKET_META:
4902 case PTR_TO_PACKET_END:
4903 verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
4904 off, size, regno, reg->id, off, mem_size);
4908 verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n",
4909 mem_size, off, size);
4915 /* check read/write into a memory region with possible variable offset */
4916 static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno,
4917 int off, int size, u32 mem_size,
4918 bool zero_size_allowed)
4920 struct bpf_verifier_state *vstate = env->cur_state;
4921 struct bpf_func_state *state = vstate->frame[vstate->curframe];
4922 struct bpf_reg_state *reg = &state->regs[regno];
4925 /* We may have adjusted the register pointing to memory region, so we
4926 * need to try adding each of min_value and max_value to off
4927 * to make sure our theoretical access will be safe.
4929 * The minimum value is only important with signed
4930 * comparisons where we can't assume the floor of a
4931 * value is 0. If we are using signed variables for our
4932 * index'es we need to make sure that whatever we use
4933 * will have a set floor within our range.
4935 if (reg->smin_value < 0 &&
4936 (reg->smin_value == S64_MIN ||
4937 (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
4938 reg->smin_value + off < 0)) {
4939 verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
4943 err = __check_mem_access(env, regno, reg->smin_value + off, size,
4944 mem_size, zero_size_allowed);
4946 verbose(env, "R%d min value is outside of the allowed memory range\n",
4951 /* If we haven't set a max value then we need to bail since we can't be
4952 * sure we won't do bad things.
4953 * If reg->umax_value + off could overflow, treat that as unbounded too.
4955 if (reg->umax_value >= BPF_MAX_VAR_OFF) {
4956 verbose(env, "R%d unbounded memory access, make sure to bounds check any such access\n",
4960 err = __check_mem_access(env, regno, reg->umax_value + off, size,
4961 mem_size, zero_size_allowed);
4963 verbose(env, "R%d max value is outside of the allowed memory range\n",
4971 static int __check_ptr_off_reg(struct bpf_verifier_env *env,
4972 const struct bpf_reg_state *reg, int regno,
4975 /* Access to this pointer-typed register or passing it to a helper
4976 * is only allowed in its original, unmodified form.
4980 verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
4981 reg_type_str(env, reg->type), regno, reg->off);
4985 if (!fixed_off_ok && reg->off) {
4986 verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
4987 reg_type_str(env, reg->type), regno, reg->off);
4991 if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
4994 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
4995 verbose(env, "variable %s access var_off=%s disallowed\n",
4996 reg_type_str(env, reg->type), tn_buf);
5003 int check_ptr_off_reg(struct bpf_verifier_env *env,
5004 const struct bpf_reg_state *reg, int regno)
5006 return __check_ptr_off_reg(env, reg, regno, false);
5009 static int map_kptr_match_type(struct bpf_verifier_env *env,
5010 struct btf_field *kptr_field,
5011 struct bpf_reg_state *reg, u32 regno)
5013 const char *targ_name = btf_type_name(kptr_field->kptr.btf, kptr_field->kptr.btf_id);
5015 const char *reg_name = "";
5017 if (btf_is_kernel(reg->btf)) {
5018 perm_flags = PTR_MAYBE_NULL | PTR_TRUSTED | MEM_RCU;
5020 /* Only unreferenced case accepts untrusted pointers */
5021 if (kptr_field->type == BPF_KPTR_UNREF)
5022 perm_flags |= PTR_UNTRUSTED;
5024 perm_flags = PTR_MAYBE_NULL | MEM_ALLOC;
5027 if (base_type(reg->type) != PTR_TO_BTF_ID || (type_flag(reg->type) & ~perm_flags))
5030 /* We need to verify reg->type and reg->btf, before accessing reg->btf */
5031 reg_name = btf_type_name(reg->btf, reg->btf_id);
5033 /* For ref_ptr case, release function check should ensure we get one
5034 * referenced PTR_TO_BTF_ID, and that its fixed offset is 0. For the
5035 * normal store of unreferenced kptr, we must ensure var_off is zero.
5036 * Since ref_ptr cannot be accessed directly by BPF insns, checks for
5037 * reg->off and reg->ref_obj_id are not needed here.
5039 if (__check_ptr_off_reg(env, reg, regno, true))
5042 /* A full type match is needed, as BTF can be vmlinux, module or prog BTF, and
5043 * we also need to take into account the reg->off.
5045 * We want to support cases like:
5053 * v = func(); // PTR_TO_BTF_ID
5054 * val->foo = v; // reg->off is zero, btf and btf_id match type
5055 * val->bar = &v->br; // reg->off is still zero, but we need to retry with
5056 * // first member type of struct after comparison fails
5057 * val->baz = &v->bz; // reg->off is non-zero, so struct needs to be walked
5060 * In the kptr_ref case, check_func_arg_reg_off already ensures reg->off
5061 * is zero. We must also ensure that btf_struct_ids_match does not walk
5062 * the struct to match type against first member of struct, i.e. reject
5063 * second case from above. Hence, when type is BPF_KPTR_REF, we set
5064 * strict mode to true for type match.
5066 if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
5067 kptr_field->kptr.btf, kptr_field->kptr.btf_id,
5068 kptr_field->type == BPF_KPTR_REF))
5072 verbose(env, "invalid kptr access, R%d type=%s%s ", regno,
5073 reg_type_str(env, reg->type), reg_name);
5074 verbose(env, "expected=%s%s", reg_type_str(env, PTR_TO_BTF_ID), targ_name);
5075 if (kptr_field->type == BPF_KPTR_UNREF)
5076 verbose(env, " or %s%s\n", reg_type_str(env, PTR_TO_BTF_ID | PTR_UNTRUSTED),
5083 /* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock()
5084 * can dereference RCU protected pointers and result is PTR_TRUSTED.
5086 static bool in_rcu_cs(struct bpf_verifier_env *env)
5088 return env->cur_state->active_rcu_lock ||
5089 env->cur_state->active_lock.ptr ||
5090 !env->prog->aux->sleepable;
5093 /* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */
5094 BTF_SET_START(rcu_protected_types)
5095 BTF_ID(struct, prog_test_ref_kfunc)
5096 BTF_ID(struct, cgroup)
5097 BTF_ID(struct, bpf_cpumask)
5098 BTF_ID(struct, task_struct)
5099 BTF_SET_END(rcu_protected_types)
5101 static bool rcu_protected_object(const struct btf *btf, u32 btf_id)
5103 if (!btf_is_kernel(btf))
5105 return btf_id_set_contains(&rcu_protected_types, btf_id);
5108 static bool rcu_safe_kptr(const struct btf_field *field)
5110 const struct btf_field_kptr *kptr = &field->kptr;
5112 return field->type == BPF_KPTR_REF && rcu_protected_object(kptr->btf, kptr->btf_id);
5115 static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno,
5116 int value_regno, int insn_idx,
5117 struct btf_field *kptr_field)
5119 struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
5120 int class = BPF_CLASS(insn->code);
5121 struct bpf_reg_state *val_reg;
5123 /* Things we already checked for in check_map_access and caller:
5124 * - Reject cases where variable offset may touch kptr
5125 * - size of access (must be BPF_DW)
5126 * - tnum_is_const(reg->var_off)
5127 * - kptr_field->offset == off + reg->var_off.value
5129 /* Only BPF_[LDX,STX,ST] | BPF_MEM | BPF_DW is supported */
5130 if (BPF_MODE(insn->code) != BPF_MEM) {
5131 verbose(env, "kptr in map can only be accessed using BPF_MEM instruction mode\n");
5135 /* We only allow loading referenced kptr, since it will be marked as
5136 * untrusted, similar to unreferenced kptr.
5138 if (class != BPF_LDX && kptr_field->type == BPF_KPTR_REF) {
5139 verbose(env, "store to referenced kptr disallowed\n");
5143 if (class == BPF_LDX) {
5144 val_reg = reg_state(env, value_regno);
5145 /* We can simply mark the value_regno receiving the pointer
5146 * value from map as PTR_TO_BTF_ID, with the correct type.
5148 mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, kptr_field->kptr.btf,
5149 kptr_field->kptr.btf_id,
5150 rcu_safe_kptr(kptr_field) && in_rcu_cs(env) ?
5151 PTR_MAYBE_NULL | MEM_RCU :
5152 PTR_MAYBE_NULL | PTR_UNTRUSTED);
5153 /* For mark_ptr_or_null_reg */
5154 val_reg->id = ++env->id_gen;
5155 } else if (class == BPF_STX) {
5156 val_reg = reg_state(env, value_regno);
5157 if (!register_is_null(val_reg) &&
5158 map_kptr_match_type(env, kptr_field, val_reg, value_regno))
5160 } else if (class == BPF_ST) {
5162 verbose(env, "BPF_ST imm must be 0 when storing to kptr at off=%u\n",
5163 kptr_field->offset);
5167 verbose(env, "kptr in map can only be accessed using BPF_LDX/BPF_STX/BPF_ST\n");
5173 /* check read/write into a map element with possible variable offset */
5174 static int check_map_access(struct bpf_verifier_env *env, u32 regno,
5175 int off, int size, bool zero_size_allowed,
5176 enum bpf_access_src src)
5178 struct bpf_verifier_state *vstate = env->cur_state;
5179 struct bpf_func_state *state = vstate->frame[vstate->curframe];
5180 struct bpf_reg_state *reg = &state->regs[regno];
5181 struct bpf_map *map = reg->map_ptr;
5182 struct btf_record *rec;
5185 err = check_mem_region_access(env, regno, off, size, map->value_size,
5190 if (IS_ERR_OR_NULL(map->record))
5193 for (i = 0; i < rec->cnt; i++) {
5194 struct btf_field *field = &rec->fields[i];
5195 u32 p = field->offset;
5197 /* If any part of a field can be touched by load/store, reject
5198 * this program. To check that [x1, x2) overlaps with [y1, y2),
5199 * it is sufficient to check x1 < y2 && y1 < x2.
5201 if (reg->smin_value + off < p + btf_field_type_size(field->type) &&
5202 p < reg->umax_value + off + size) {
5203 switch (field->type) {
5204 case BPF_KPTR_UNREF:
5206 if (src != ACCESS_DIRECT) {
5207 verbose(env, "kptr cannot be accessed indirectly by helper\n");
5210 if (!tnum_is_const(reg->var_off)) {
5211 verbose(env, "kptr access cannot have variable offset\n");
5214 if (p != off + reg->var_off.value) {
5215 verbose(env, "kptr access misaligned expected=%u off=%llu\n",
5216 p, off + reg->var_off.value);
5219 if (size != bpf_size_to_bytes(BPF_DW)) {
5220 verbose(env, "kptr access size must be BPF_DW\n");
5225 verbose(env, "%s cannot be accessed directly by load/store\n",
5226 btf_field_type_name(field->type));
5234 #define MAX_PACKET_OFF 0xffff
5236 static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
5237 const struct bpf_call_arg_meta *meta,
5238 enum bpf_access_type t)
5240 enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
5242 switch (prog_type) {
5243 /* Program types only with direct read access go here! */
5244 case BPF_PROG_TYPE_LWT_IN:
5245 case BPF_PROG_TYPE_LWT_OUT:
5246 case BPF_PROG_TYPE_LWT_SEG6LOCAL:
5247 case BPF_PROG_TYPE_SK_REUSEPORT:
5248 case BPF_PROG_TYPE_FLOW_DISSECTOR:
5249 case BPF_PROG_TYPE_CGROUP_SKB:
5254 /* Program types with direct read + write access go here! */
5255 case BPF_PROG_TYPE_SCHED_CLS:
5256 case BPF_PROG_TYPE_SCHED_ACT:
5257 case BPF_PROG_TYPE_XDP:
5258 case BPF_PROG_TYPE_LWT_XMIT:
5259 case BPF_PROG_TYPE_SK_SKB:
5260 case BPF_PROG_TYPE_SK_MSG:
5262 return meta->pkt_access;
5264 env->seen_direct_write = true;
5267 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
5269 env->seen_direct_write = true;
5278 static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
5279 int size, bool zero_size_allowed)
5281 struct bpf_reg_state *regs = cur_regs(env);
5282 struct bpf_reg_state *reg = ®s[regno];
5285 /* We may have added a variable offset to the packet pointer; but any
5286 * reg->range we have comes after that. We are only checking the fixed
5290 /* We don't allow negative numbers, because we aren't tracking enough
5291 * detail to prove they're safe.
5293 if (reg->smin_value < 0) {
5294 verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
5299 err = reg->range < 0 ? -EINVAL :
5300 __check_mem_access(env, regno, off, size, reg->range,
5303 verbose(env, "R%d offset is outside of the packet\n", regno);
5307 /* __check_mem_access has made sure "off + size - 1" is within u16.
5308 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
5309 * otherwise find_good_pkt_pointers would have refused to set range info
5310 * that __check_mem_access would have rejected this pkt access.
5311 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
5313 env->prog->aux->max_pkt_offset =
5314 max_t(u32, env->prog->aux->max_pkt_offset,
5315 off + reg->umax_value + size - 1);
5320 /* check access to 'struct bpf_context' fields. Supports fixed offsets only */
5321 static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
5322 enum bpf_access_type t, enum bpf_reg_type *reg_type,
5323 struct btf **btf, u32 *btf_id)
5325 struct bpf_insn_access_aux info = {
5326 .reg_type = *reg_type,
5330 if (env->ops->is_valid_access &&
5331 env->ops->is_valid_access(off, size, t, env->prog, &info)) {
5332 /* A non zero info.ctx_field_size indicates that this field is a
5333 * candidate for later verifier transformation to load the whole
5334 * field and then apply a mask when accessed with a narrower
5335 * access than actual ctx access size. A zero info.ctx_field_size
5336 * will only allow for whole field access and rejects any other
5337 * type of narrower access.
5339 *reg_type = info.reg_type;
5341 if (base_type(*reg_type) == PTR_TO_BTF_ID) {
5343 *btf_id = info.btf_id;
5345 env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
5347 /* remember the offset of last byte accessed in ctx */
5348 if (env->prog->aux->max_ctx_offset < off + size)
5349 env->prog->aux->max_ctx_offset = off + size;
5353 verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size);
5357 static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
5360 if (size < 0 || off < 0 ||
5361 (u64)off + size > sizeof(struct bpf_flow_keys)) {
5362 verbose(env, "invalid access to flow keys off=%d size=%d\n",
5369 static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
5370 u32 regno, int off, int size,
5371 enum bpf_access_type t)
5373 struct bpf_reg_state *regs = cur_regs(env);
5374 struct bpf_reg_state *reg = ®s[regno];
5375 struct bpf_insn_access_aux info = {};
5378 if (reg->smin_value < 0) {
5379 verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
5384 switch (reg->type) {
5385 case PTR_TO_SOCK_COMMON:
5386 valid = bpf_sock_common_is_valid_access(off, size, t, &info);
5389 valid = bpf_sock_is_valid_access(off, size, t, &info);
5391 case PTR_TO_TCP_SOCK:
5392 valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
5394 case PTR_TO_XDP_SOCK:
5395 valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
5403 env->insn_aux_data[insn_idx].ctx_field_size =
5404 info.ctx_field_size;
5408 verbose(env, "R%d invalid %s access off=%d size=%d\n",
5409 regno, reg_type_str(env, reg->type), off, size);
5414 static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
5416 return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
5419 static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
5421 const struct bpf_reg_state *reg = reg_state(env, regno);
5423 return reg->type == PTR_TO_CTX;
5426 static bool is_sk_reg(struct bpf_verifier_env *env, int regno)
5428 const struct bpf_reg_state *reg = reg_state(env, regno);
5430 return type_is_sk_pointer(reg->type);
5433 static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
5435 const struct bpf_reg_state *reg = reg_state(env, regno);
5437 return type_is_pkt_pointer(reg->type);
5440 static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
5442 const struct bpf_reg_state *reg = reg_state(env, regno);
5444 /* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
5445 return reg->type == PTR_TO_FLOW_KEYS;
5448 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
5450 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
5451 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
5452 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
5454 [CONST_PTR_TO_MAP] = btf_bpf_map_id,
5457 static bool is_trusted_reg(const struct bpf_reg_state *reg)
5459 /* A referenced register is always trusted. */
5460 if (reg->ref_obj_id)
5463 /* Types listed in the reg2btf_ids are always trusted */
5464 if (reg2btf_ids[base_type(reg->type)])
5467 /* If a register is not referenced, it is trusted if it has the
5468 * MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the
5469 * other type modifiers may be safe, but we elect to take an opt-in
5470 * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are
5473 * Eventually, we should make PTR_TRUSTED the single source of truth
5474 * for whether a register is trusted.
5476 return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS &&
5477 !bpf_type_has_unsafe_modifiers(reg->type);
5480 static bool is_rcu_reg(const struct bpf_reg_state *reg)
5482 return reg->type & MEM_RCU;
5485 static void clear_trusted_flags(enum bpf_type_flag *flag)
5487 *flag &= ~(BPF_REG_TRUSTED_MODIFIERS | MEM_RCU);
5490 static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
5491 const struct bpf_reg_state *reg,
5492 int off, int size, bool strict)
5494 struct tnum reg_off;
5497 /* Byte size accesses are always allowed. */
5498 if (!strict || size == 1)
5501 /* For platforms that do not have a Kconfig enabling
5502 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
5503 * NET_IP_ALIGN is universally set to '2'. And on platforms
5504 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
5505 * to this code only in strict mode where we want to emulate
5506 * the NET_IP_ALIGN==2 checking. Therefore use an
5507 * unconditional IP align value of '2'.
5511 reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off));
5512 if (!tnum_is_aligned(reg_off, size)) {
5515 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5517 "misaligned packet access off %d+%s+%d+%d size %d\n",
5518 ip_align, tn_buf, reg->off, off, size);
5525 static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
5526 const struct bpf_reg_state *reg,
5527 const char *pointer_desc,
5528 int off, int size, bool strict)
5530 struct tnum reg_off;
5532 /* Byte size accesses are always allowed. */
5533 if (!strict || size == 1)
5536 reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off));
5537 if (!tnum_is_aligned(reg_off, size)) {
5540 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5541 verbose(env, "misaligned %saccess off %s+%d+%d size %d\n",
5542 pointer_desc, tn_buf, reg->off, off, size);
5549 static int check_ptr_alignment(struct bpf_verifier_env *env,
5550 const struct bpf_reg_state *reg, int off,
5551 int size, bool strict_alignment_once)
5553 bool strict = env->strict_alignment || strict_alignment_once;
5554 const char *pointer_desc = "";
5556 switch (reg->type) {
5558 case PTR_TO_PACKET_META:
5559 /* Special case, because of NET_IP_ALIGN. Given metadata sits
5560 * right in front, treat it the very same way.
5562 return check_pkt_ptr_alignment(env, reg, off, size, strict);
5563 case PTR_TO_FLOW_KEYS:
5564 pointer_desc = "flow keys ";
5566 case PTR_TO_MAP_KEY:
5567 pointer_desc = "key ";
5569 case PTR_TO_MAP_VALUE:
5570 pointer_desc = "value ";
5573 pointer_desc = "context ";
5576 pointer_desc = "stack ";
5577 /* The stack spill tracking logic in check_stack_write_fixed_off()
5578 * and check_stack_read_fixed_off() relies on stack accesses being
5584 pointer_desc = "sock ";
5586 case PTR_TO_SOCK_COMMON:
5587 pointer_desc = "sock_common ";
5589 case PTR_TO_TCP_SOCK:
5590 pointer_desc = "tcp_sock ";
5592 case PTR_TO_XDP_SOCK:
5593 pointer_desc = "xdp_sock ";
5598 return check_generic_ptr_alignment(env, reg, pointer_desc, off, size,
5602 static int update_stack_depth(struct bpf_verifier_env *env,
5603 const struct bpf_func_state *func,
5606 u16 stack = env->subprog_info[func->subprogno].stack_depth;
5611 /* update known max for given subprogram */
5612 env->subprog_info[func->subprogno].stack_depth = -off;
5616 /* starting from main bpf function walk all instructions of the function
5617 * and recursively walk all callees that given function can call.
5618 * Ignore jump and exit insns.
5619 * Since recursion is prevented by check_cfg() this algorithm
5620 * only needs a local stack of MAX_CALL_FRAMES to remember callsites
5622 static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx)
5624 struct bpf_subprog_info *subprog = env->subprog_info;
5625 struct bpf_insn *insn = env->prog->insnsi;
5626 int depth = 0, frame = 0, i, subprog_end;
5627 bool tail_call_reachable = false;
5628 int ret_insn[MAX_CALL_FRAMES];
5629 int ret_prog[MAX_CALL_FRAMES];
5632 i = subprog[idx].start;
5634 /* protect against potential stack overflow that might happen when
5635 * bpf2bpf calls get combined with tailcalls. Limit the caller's stack
5636 * depth for such case down to 256 so that the worst case scenario
5637 * would result in 8k stack size (32 which is tailcall limit * 256 =
5640 * To get the idea what might happen, see an example:
5641 * func1 -> sub rsp, 128
5642 * subfunc1 -> sub rsp, 256
5643 * tailcall1 -> add rsp, 256
5644 * func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320)
5645 * subfunc2 -> sub rsp, 64
5646 * subfunc22 -> sub rsp, 128
5647 * tailcall2 -> add rsp, 128
5648 * func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416)
5650 * tailcall will unwind the current stack frame but it will not get rid
5651 * of caller's stack as shown on the example above.
5653 if (idx && subprog[idx].has_tail_call && depth >= 256) {
5655 "tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n",
5659 /* round up to 32-bytes, since this is granularity
5660 * of interpreter stack size
5662 depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
5663 if (depth > MAX_BPF_STACK) {
5664 verbose(env, "combined stack size of %d calls is %d. Too large\n",
5669 subprog_end = subprog[idx + 1].start;
5670 for (; i < subprog_end; i++) {
5671 int next_insn, sidx;
5673 if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i))
5675 /* remember insn and function to return to */
5676 ret_insn[frame] = i + 1;
5677 ret_prog[frame] = idx;
5679 /* find the callee */
5680 next_insn = i + insn[i].imm + 1;
5681 sidx = find_subprog(env, next_insn);
5683 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
5687 if (subprog[sidx].is_async_cb) {
5688 if (subprog[sidx].has_tail_call) {
5689 verbose(env, "verifier bug. subprog has tail_call and async cb\n");
5692 /* async callbacks don't increase bpf prog stack size unless called directly */
5693 if (!bpf_pseudo_call(insn + i))
5699 if (subprog[idx].has_tail_call)
5700 tail_call_reachable = true;
5703 if (frame >= MAX_CALL_FRAMES) {
5704 verbose(env, "the call stack of %d frames is too deep !\n",
5710 /* if tail call got detected across bpf2bpf calls then mark each of the
5711 * currently present subprog frames as tail call reachable subprogs;
5712 * this info will be utilized by JIT so that we will be preserving the
5713 * tail call counter throughout bpf2bpf calls combined with tailcalls
5715 if (tail_call_reachable)
5716 for (j = 0; j < frame; j++)
5717 subprog[ret_prog[j]].tail_call_reachable = true;
5718 if (subprog[0].tail_call_reachable)
5719 env->prog->aux->tail_call_reachable = true;
5721 /* end of for() loop means the last insn of the 'subprog'
5722 * was reached. Doesn't matter whether it was JA or EXIT
5726 depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
5728 i = ret_insn[frame];
5729 idx = ret_prog[frame];
5733 static int check_max_stack_depth(struct bpf_verifier_env *env)
5735 struct bpf_subprog_info *si = env->subprog_info;
5738 for (int i = 0; i < env->subprog_cnt; i++) {
5739 if (!i || si[i].is_async_cb) {
5740 ret = check_max_stack_depth_subprog(env, i);
5749 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
5750 static int get_callee_stack_depth(struct bpf_verifier_env *env,
5751 const struct bpf_insn *insn, int idx)
5753 int start = idx + insn->imm + 1, subprog;
5755 subprog = find_subprog(env, start);
5757 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
5761 return env->subprog_info[subprog].stack_depth;
5765 static int __check_buffer_access(struct bpf_verifier_env *env,
5766 const char *buf_info,
5767 const struct bpf_reg_state *reg,
5768 int regno, int off, int size)
5772 "R%d invalid %s buffer access: off=%d, size=%d\n",
5773 regno, buf_info, off, size);
5776 if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
5779 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5781 "R%d invalid variable buffer offset: off=%d, var_off=%s\n",
5782 regno, off, tn_buf);
5789 static int check_tp_buffer_access(struct bpf_verifier_env *env,
5790 const struct bpf_reg_state *reg,
5791 int regno, int off, int size)
5795 err = __check_buffer_access(env, "tracepoint", reg, regno, off, size);
5799 if (off + size > env->prog->aux->max_tp_access)
5800 env->prog->aux->max_tp_access = off + size;
5805 static int check_buffer_access(struct bpf_verifier_env *env,
5806 const struct bpf_reg_state *reg,
5807 int regno, int off, int size,
5808 bool zero_size_allowed,
5811 const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr";
5814 err = __check_buffer_access(env, buf_info, reg, regno, off, size);
5818 if (off + size > *max_access)
5819 *max_access = off + size;
5824 /* BPF architecture zero extends alu32 ops into 64-bit registesr */
5825 static void zext_32_to_64(struct bpf_reg_state *reg)
5827 reg->var_off = tnum_subreg(reg->var_off);
5828 __reg_assign_32_into_64(reg);
5831 /* truncate register to smaller size (in bytes)
5832 * must be called with size < BPF_REG_SIZE
5834 static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
5838 /* clear high bits in bit representation */
5839 reg->var_off = tnum_cast(reg->var_off, size);
5841 /* fix arithmetic bounds */
5842 mask = ((u64)1 << (size * 8)) - 1;
5843 if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) {
5844 reg->umin_value &= mask;
5845 reg->umax_value &= mask;
5847 reg->umin_value = 0;
5848 reg->umax_value = mask;
5850 reg->smin_value = reg->umin_value;
5851 reg->smax_value = reg->umax_value;
5853 /* If size is smaller than 32bit register the 32bit register
5854 * values are also truncated so we push 64-bit bounds into
5855 * 32-bit bounds. Above were truncated < 32-bits already.
5859 __reg_combine_64_into_32(reg);
5862 static void set_sext64_default_val(struct bpf_reg_state *reg, int size)
5865 reg->smin_value = reg->s32_min_value = S8_MIN;
5866 reg->smax_value = reg->s32_max_value = S8_MAX;
5867 } else if (size == 2) {
5868 reg->smin_value = reg->s32_min_value = S16_MIN;
5869 reg->smax_value = reg->s32_max_value = S16_MAX;
5872 reg->smin_value = reg->s32_min_value = S32_MIN;
5873 reg->smax_value = reg->s32_max_value = S32_MAX;
5875 reg->umin_value = reg->u32_min_value = 0;
5876 reg->umax_value = U64_MAX;
5877 reg->u32_max_value = U32_MAX;
5878 reg->var_off = tnum_unknown;
5881 static void coerce_reg_to_size_sx(struct bpf_reg_state *reg, int size)
5883 s64 init_s64_max, init_s64_min, s64_max, s64_min, u64_cval;
5884 u64 top_smax_value, top_smin_value;
5885 u64 num_bits = size * 8;
5887 if (tnum_is_const(reg->var_off)) {
5888 u64_cval = reg->var_off.value;
5890 reg->var_off = tnum_const((s8)u64_cval);
5892 reg->var_off = tnum_const((s16)u64_cval);
5895 reg->var_off = tnum_const((s32)u64_cval);
5897 u64_cval = reg->var_off.value;
5898 reg->smax_value = reg->smin_value = u64_cval;
5899 reg->umax_value = reg->umin_value = u64_cval;
5900 reg->s32_max_value = reg->s32_min_value = u64_cval;
5901 reg->u32_max_value = reg->u32_min_value = u64_cval;
5905 top_smax_value = ((u64)reg->smax_value >> num_bits) << num_bits;
5906 top_smin_value = ((u64)reg->smin_value >> num_bits) << num_bits;
5908 if (top_smax_value != top_smin_value)
5911 /* find the s64_min and s64_min after sign extension */
5913 init_s64_max = (s8)reg->smax_value;
5914 init_s64_min = (s8)reg->smin_value;
5915 } else if (size == 2) {
5916 init_s64_max = (s16)reg->smax_value;
5917 init_s64_min = (s16)reg->smin_value;
5919 init_s64_max = (s32)reg->smax_value;
5920 init_s64_min = (s32)reg->smin_value;
5923 s64_max = max(init_s64_max, init_s64_min);
5924 s64_min = min(init_s64_max, init_s64_min);
5926 /* both of s64_max/s64_min positive or negative */
5927 if ((s64_max >= 0) == (s64_min >= 0)) {
5928 reg->smin_value = reg->s32_min_value = s64_min;
5929 reg->smax_value = reg->s32_max_value = s64_max;
5930 reg->umin_value = reg->u32_min_value = s64_min;
5931 reg->umax_value = reg->u32_max_value = s64_max;
5932 reg->var_off = tnum_range(s64_min, s64_max);
5937 set_sext64_default_val(reg, size);
5940 static void set_sext32_default_val(struct bpf_reg_state *reg, int size)
5943 reg->s32_min_value = S8_MIN;
5944 reg->s32_max_value = S8_MAX;
5947 reg->s32_min_value = S16_MIN;
5948 reg->s32_max_value = S16_MAX;
5950 reg->u32_min_value = 0;
5951 reg->u32_max_value = U32_MAX;
5954 static void coerce_subreg_to_size_sx(struct bpf_reg_state *reg, int size)
5956 s32 init_s32_max, init_s32_min, s32_max, s32_min, u32_val;
5957 u32 top_smax_value, top_smin_value;
5958 u32 num_bits = size * 8;
5960 if (tnum_is_const(reg->var_off)) {
5961 u32_val = reg->var_off.value;
5963 reg->var_off = tnum_const((s8)u32_val);
5965 reg->var_off = tnum_const((s16)u32_val);
5967 u32_val = reg->var_off.value;
5968 reg->s32_min_value = reg->s32_max_value = u32_val;
5969 reg->u32_min_value = reg->u32_max_value = u32_val;
5973 top_smax_value = ((u32)reg->s32_max_value >> num_bits) << num_bits;
5974 top_smin_value = ((u32)reg->s32_min_value >> num_bits) << num_bits;
5976 if (top_smax_value != top_smin_value)
5979 /* find the s32_min and s32_min after sign extension */
5981 init_s32_max = (s8)reg->s32_max_value;
5982 init_s32_min = (s8)reg->s32_min_value;
5985 init_s32_max = (s16)reg->s32_max_value;
5986 init_s32_min = (s16)reg->s32_min_value;
5988 s32_max = max(init_s32_max, init_s32_min);
5989 s32_min = min(init_s32_max, init_s32_min);
5991 if ((s32_min >= 0) == (s32_max >= 0)) {
5992 reg->s32_min_value = s32_min;
5993 reg->s32_max_value = s32_max;
5994 reg->u32_min_value = (u32)s32_min;
5995 reg->u32_max_value = (u32)s32_max;
6000 set_sext32_default_val(reg, size);
6003 static bool bpf_map_is_rdonly(const struct bpf_map *map)
6005 /* A map is considered read-only if the following condition are true:
6007 * 1) BPF program side cannot change any of the map content. The
6008 * BPF_F_RDONLY_PROG flag is throughout the lifetime of a map
6009 * and was set at map creation time.
6010 * 2) The map value(s) have been initialized from user space by a
6011 * loader and then "frozen", such that no new map update/delete
6012 * operations from syscall side are possible for the rest of
6013 * the map's lifetime from that point onwards.
6014 * 3) Any parallel/pending map update/delete operations from syscall
6015 * side have been completed. Only after that point, it's safe to
6016 * assume that map value(s) are immutable.
6018 return (map->map_flags & BPF_F_RDONLY_PROG) &&
6019 READ_ONCE(map->frozen) &&
6020 !bpf_map_write_active(map);
6023 static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val,
6030 err = map->ops->map_direct_value_addr(map, &addr, off);
6033 ptr = (void *)(long)addr + off;
6037 *val = is_ldsx ? (s64)*(s8 *)ptr : (u64)*(u8 *)ptr;
6040 *val = is_ldsx ? (s64)*(s16 *)ptr : (u64)*(u16 *)ptr;
6043 *val = is_ldsx ? (s64)*(s32 *)ptr : (u64)*(u32 *)ptr;
6054 #define BTF_TYPE_SAFE_RCU(__type) __PASTE(__type, __safe_rcu)
6055 #define BTF_TYPE_SAFE_RCU_OR_NULL(__type) __PASTE(__type, __safe_rcu_or_null)
6056 #define BTF_TYPE_SAFE_TRUSTED(__type) __PASTE(__type, __safe_trusted)
6059 * Allow list few fields as RCU trusted or full trusted.
6060 * This logic doesn't allow mix tagging and will be removed once GCC supports
6064 /* RCU trusted: these fields are trusted in RCU CS and never NULL */
6065 BTF_TYPE_SAFE_RCU(struct task_struct) {
6066 const cpumask_t *cpus_ptr;
6067 struct css_set __rcu *cgroups;
6068 struct task_struct __rcu *real_parent;
6069 struct task_struct *group_leader;
6072 BTF_TYPE_SAFE_RCU(struct cgroup) {
6073 /* cgrp->kn is always accessible as documented in kernel/cgroup/cgroup.c */
6074 struct kernfs_node *kn;
6077 BTF_TYPE_SAFE_RCU(struct css_set) {
6078 struct cgroup *dfl_cgrp;
6081 /* RCU trusted: these fields are trusted in RCU CS and can be NULL */
6082 BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) {
6083 struct file __rcu *exe_file;
6086 /* skb->sk, req->sk are not RCU protected, but we mark them as such
6087 * because bpf prog accessible sockets are SOCK_RCU_FREE.
6089 BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff) {
6093 BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock) {
6097 /* full trusted: these fields are trusted even outside of RCU CS and never NULL */
6098 BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta) {
6099 struct seq_file *seq;
6102 BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task) {
6103 struct bpf_iter_meta *meta;
6104 struct task_struct *task;
6107 BTF_TYPE_SAFE_TRUSTED(struct linux_binprm) {
6111 BTF_TYPE_SAFE_TRUSTED(struct file) {
6112 struct inode *f_inode;
6115 BTF_TYPE_SAFE_TRUSTED(struct dentry) {
6116 /* no negative dentry-s in places where bpf can see it */
6117 struct inode *d_inode;
6120 BTF_TYPE_SAFE_TRUSTED(struct socket) {
6124 static bool type_is_rcu(struct bpf_verifier_env *env,
6125 struct bpf_reg_state *reg,
6126 const char *field_name, u32 btf_id)
6128 BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct task_struct));
6129 BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup));
6130 BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct css_set));
6132 return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu");
6135 static bool type_is_rcu_or_null(struct bpf_verifier_env *env,
6136 struct bpf_reg_state *reg,
6137 const char *field_name, u32 btf_id)
6139 BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct));
6140 BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff));
6141 BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock));
6143 return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu_or_null");
6146 static bool type_is_trusted(struct bpf_verifier_env *env,
6147 struct bpf_reg_state *reg,
6148 const char *field_name, u32 btf_id)
6150 BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta));
6151 BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task));
6152 BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct linux_binprm));
6153 BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct file));
6154 BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct dentry));
6155 BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct socket));
6157 return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted");
6160 static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
6161 struct bpf_reg_state *regs,
6162 int regno, int off, int size,
6163 enum bpf_access_type atype,
6166 struct bpf_reg_state *reg = regs + regno;
6167 const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
6168 const char *tname = btf_name_by_offset(reg->btf, t->name_off);
6169 const char *field_name = NULL;
6170 enum bpf_type_flag flag = 0;
6174 if (!env->allow_ptr_leaks) {
6176 "'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
6180 if (!env->prog->gpl_compatible && btf_is_kernel(reg->btf)) {
6182 "Cannot access kernel 'struct %s' from non-GPL compatible program\n",
6188 "R%d is ptr_%s invalid negative access: off=%d\n",
6192 if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
6195 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
6197 "R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
6198 regno, tname, off, tn_buf);
6202 if (reg->type & MEM_USER) {
6204 "R%d is ptr_%s access user memory: off=%d\n",
6209 if (reg->type & MEM_PERCPU) {
6211 "R%d is ptr_%s access percpu memory: off=%d\n",
6216 if (env->ops->btf_struct_access && !type_is_alloc(reg->type) && atype == BPF_WRITE) {
6217 if (!btf_is_kernel(reg->btf)) {
6218 verbose(env, "verifier internal error: reg->btf must be kernel btf\n");
6221 ret = env->ops->btf_struct_access(&env->log, reg, off, size);
6223 /* Writes are permitted with default btf_struct_access for
6224 * program allocated objects (which always have ref_obj_id > 0),
6225 * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC.
6227 if (atype != BPF_READ && !type_is_ptr_alloc_obj(reg->type)) {
6228 verbose(env, "only read is supported\n");
6232 if (type_is_alloc(reg->type) && !type_is_non_owning_ref(reg->type) &&
6234 verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n");
6238 ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag, &field_name);
6244 if (ret != PTR_TO_BTF_ID) {
6247 } else if (type_flag(reg->type) & PTR_UNTRUSTED) {
6248 /* If this is an untrusted pointer, all pointers formed by walking it
6249 * also inherit the untrusted flag.
6251 flag = PTR_UNTRUSTED;
6253 } else if (is_trusted_reg(reg) || is_rcu_reg(reg)) {
6254 /* By default any pointer obtained from walking a trusted pointer is no
6255 * longer trusted, unless the field being accessed has explicitly been
6256 * marked as inheriting its parent's state of trust (either full or RCU).
6258 * 'cgroups' pointer is untrusted if task->cgroups dereference
6259 * happened in a sleepable program outside of bpf_rcu_read_lock()
6260 * section. In a non-sleepable program it's trusted while in RCU CS (aka MEM_RCU).
6261 * Note bpf_rcu_read_unlock() converts MEM_RCU pointers to PTR_UNTRUSTED.
6263 * A regular RCU-protected pointer with __rcu tag can also be deemed
6264 * trusted if we are in an RCU CS. Such pointer can be NULL.
6266 if (type_is_trusted(env, reg, field_name, btf_id)) {
6267 flag |= PTR_TRUSTED;
6268 } else if (in_rcu_cs(env) && !type_may_be_null(reg->type)) {
6269 if (type_is_rcu(env, reg, field_name, btf_id)) {
6270 /* ignore __rcu tag and mark it MEM_RCU */
6272 } else if (flag & MEM_RCU ||
6273 type_is_rcu_or_null(env, reg, field_name, btf_id)) {
6274 /* __rcu tagged pointers can be NULL */
6275 flag |= MEM_RCU | PTR_MAYBE_NULL;
6277 /* We always trust them */
6278 if (type_is_rcu_or_null(env, reg, field_name, btf_id) &&
6279 flag & PTR_UNTRUSTED)
6280 flag &= ~PTR_UNTRUSTED;
6281 } else if (flag & (MEM_PERCPU | MEM_USER)) {
6284 /* walking unknown pointers yields old deprecated PTR_TO_BTF_ID */
6285 clear_trusted_flags(&flag);
6289 * If not in RCU CS or MEM_RCU pointer can be NULL then
6290 * aggressively mark as untrusted otherwise such
6291 * pointers will be plain PTR_TO_BTF_ID without flags
6292 * and will be allowed to be passed into helpers for
6295 flag = PTR_UNTRUSTED;
6298 /* Old compat. Deprecated */
6299 clear_trusted_flags(&flag);
6302 if (atype == BPF_READ && value_regno >= 0)
6303 mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag);
6308 static int check_ptr_to_map_access(struct bpf_verifier_env *env,
6309 struct bpf_reg_state *regs,
6310 int regno, int off, int size,
6311 enum bpf_access_type atype,
6314 struct bpf_reg_state *reg = regs + regno;
6315 struct bpf_map *map = reg->map_ptr;
6316 struct bpf_reg_state map_reg;
6317 enum bpf_type_flag flag = 0;
6318 const struct btf_type *t;
6324 verbose(env, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
6328 if (!map->ops->map_btf_id || !*map->ops->map_btf_id) {
6329 verbose(env, "map_ptr access not supported for map type %d\n",
6334 t = btf_type_by_id(btf_vmlinux, *map->ops->map_btf_id);
6335 tname = btf_name_by_offset(btf_vmlinux, t->name_off);
6337 if (!env->allow_ptr_leaks) {
6339 "'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
6345 verbose(env, "R%d is %s invalid negative access: off=%d\n",
6350 if (atype != BPF_READ) {
6351 verbose(env, "only read from %s is supported\n", tname);
6355 /* Simulate access to a PTR_TO_BTF_ID */
6356 memset(&map_reg, 0, sizeof(map_reg));
6357 mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0);
6358 ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag, NULL);
6362 if (value_regno >= 0)
6363 mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag);
6368 /* Check that the stack access at the given offset is within bounds. The
6369 * maximum valid offset is -1.
6371 * The minimum valid offset is -MAX_BPF_STACK for writes, and
6372 * -state->allocated_stack for reads.
6374 static int check_stack_slot_within_bounds(int off,
6375 struct bpf_func_state *state,
6376 enum bpf_access_type t)
6381 min_valid_off = -MAX_BPF_STACK;
6383 min_valid_off = -state->allocated_stack;
6385 if (off < min_valid_off || off > -1)
6390 /* Check that the stack access at 'regno + off' falls within the maximum stack
6393 * 'off' includes `regno->offset`, but not its dynamic part (if any).
6395 static int check_stack_access_within_bounds(
6396 struct bpf_verifier_env *env,
6397 int regno, int off, int access_size,
6398 enum bpf_access_src src, enum bpf_access_type type)
6400 struct bpf_reg_state *regs = cur_regs(env);
6401 struct bpf_reg_state *reg = regs + regno;
6402 struct bpf_func_state *state = func(env, reg);
6403 int min_off, max_off;
6407 if (src == ACCESS_HELPER)
6408 /* We don't know if helpers are reading or writing (or both). */
6409 err_extra = " indirect access to";
6410 else if (type == BPF_READ)
6411 err_extra = " read from";
6413 err_extra = " write to";
6415 if (tnum_is_const(reg->var_off)) {
6416 min_off = reg->var_off.value + off;
6417 if (access_size > 0)
6418 max_off = min_off + access_size - 1;
6422 if (reg->smax_value >= BPF_MAX_VAR_OFF ||
6423 reg->smin_value <= -BPF_MAX_VAR_OFF) {
6424 verbose(env, "invalid unbounded variable-offset%s stack R%d\n",
6428 min_off = reg->smin_value + off;
6429 if (access_size > 0)
6430 max_off = reg->smax_value + off + access_size - 1;
6435 err = check_stack_slot_within_bounds(min_off, state, type);
6437 err = check_stack_slot_within_bounds(max_off, state, type);
6440 if (tnum_is_const(reg->var_off)) {
6441 verbose(env, "invalid%s stack R%d off=%d size=%d\n",
6442 err_extra, regno, off, access_size);
6446 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
6447 verbose(env, "invalid variable-offset%s stack R%d var_off=%s size=%d\n",
6448 err_extra, regno, tn_buf, access_size);
6454 /* check whether memory at (regno + off) is accessible for t = (read | write)
6455 * if t==write, value_regno is a register which value is stored into memory
6456 * if t==read, value_regno is a register which will receive the value from memory
6457 * if t==write && value_regno==-1, some unknown value is stored into memory
6458 * if t==read && value_regno==-1, don't care what we read from memory
6460 static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
6461 int off, int bpf_size, enum bpf_access_type t,
6462 int value_regno, bool strict_alignment_once, bool is_ldsx)
6464 struct bpf_reg_state *regs = cur_regs(env);
6465 struct bpf_reg_state *reg = regs + regno;
6466 struct bpf_func_state *state;
6469 size = bpf_size_to_bytes(bpf_size);
6473 /* alignment checks will add in reg->off themselves */
6474 err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
6478 /* for access checks, reg->off is just part of off */
6481 if (reg->type == PTR_TO_MAP_KEY) {
6482 if (t == BPF_WRITE) {
6483 verbose(env, "write to change key R%d not allowed\n", regno);
6487 err = check_mem_region_access(env, regno, off, size,
6488 reg->map_ptr->key_size, false);
6491 if (value_regno >= 0)
6492 mark_reg_unknown(env, regs, value_regno);
6493 } else if (reg->type == PTR_TO_MAP_VALUE) {
6494 struct btf_field *kptr_field = NULL;
6496 if (t == BPF_WRITE && value_regno >= 0 &&
6497 is_pointer_value(env, value_regno)) {
6498 verbose(env, "R%d leaks addr into map\n", value_regno);
6501 err = check_map_access_type(env, regno, off, size, t);
6504 err = check_map_access(env, regno, off, size, false, ACCESS_DIRECT);
6507 if (tnum_is_const(reg->var_off))
6508 kptr_field = btf_record_find(reg->map_ptr->record,
6509 off + reg->var_off.value, BPF_KPTR);
6511 err = check_map_kptr_access(env, regno, value_regno, insn_idx, kptr_field);
6512 } else if (t == BPF_READ && value_regno >= 0) {
6513 struct bpf_map *map = reg->map_ptr;
6515 /* if map is read-only, track its contents as scalars */
6516 if (tnum_is_const(reg->var_off) &&
6517 bpf_map_is_rdonly(map) &&
6518 map->ops->map_direct_value_addr) {
6519 int map_off = off + reg->var_off.value;
6522 err = bpf_map_direct_read(map, map_off, size,
6527 regs[value_regno].type = SCALAR_VALUE;
6528 __mark_reg_known(®s[value_regno], val);
6530 mark_reg_unknown(env, regs, value_regno);
6533 } else if (base_type(reg->type) == PTR_TO_MEM) {
6534 bool rdonly_mem = type_is_rdonly_mem(reg->type);
6536 if (type_may_be_null(reg->type)) {
6537 verbose(env, "R%d invalid mem access '%s'\n", regno,
6538 reg_type_str(env, reg->type));
6542 if (t == BPF_WRITE && rdonly_mem) {
6543 verbose(env, "R%d cannot write into %s\n",
6544 regno, reg_type_str(env, reg->type));
6548 if (t == BPF_WRITE && value_regno >= 0 &&
6549 is_pointer_value(env, value_regno)) {
6550 verbose(env, "R%d leaks addr into mem\n", value_regno);
6554 err = check_mem_region_access(env, regno, off, size,
6555 reg->mem_size, false);
6556 if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem))
6557 mark_reg_unknown(env, regs, value_regno);
6558 } else if (reg->type == PTR_TO_CTX) {
6559 enum bpf_reg_type reg_type = SCALAR_VALUE;
6560 struct btf *btf = NULL;
6563 if (t == BPF_WRITE && value_regno >= 0 &&
6564 is_pointer_value(env, value_regno)) {
6565 verbose(env, "R%d leaks addr into ctx\n", value_regno);
6569 err = check_ptr_off_reg(env, reg, regno);
6573 err = check_ctx_access(env, insn_idx, off, size, t, ®_type, &btf,
6576 verbose_linfo(env, insn_idx, "; ");
6577 if (!err && t == BPF_READ && value_regno >= 0) {
6578 /* ctx access returns either a scalar, or a
6579 * PTR_TO_PACKET[_META,_END]. In the latter
6580 * case, we know the offset is zero.
6582 if (reg_type == SCALAR_VALUE) {
6583 mark_reg_unknown(env, regs, value_regno);
6585 mark_reg_known_zero(env, regs,
6587 if (type_may_be_null(reg_type))
6588 regs[value_regno].id = ++env->id_gen;
6589 /* A load of ctx field could have different
6590 * actual load size with the one encoded in the
6591 * insn. When the dst is PTR, it is for sure not
6594 regs[value_regno].subreg_def = DEF_NOT_SUBREG;
6595 if (base_type(reg_type) == PTR_TO_BTF_ID) {
6596 regs[value_regno].btf = btf;
6597 regs[value_regno].btf_id = btf_id;
6600 regs[value_regno].type = reg_type;
6603 } else if (reg->type == PTR_TO_STACK) {
6604 /* Basic bounds checks. */
6605 err = check_stack_access_within_bounds(env, regno, off, size, ACCESS_DIRECT, t);
6609 state = func(env, reg);
6610 err = update_stack_depth(env, state, off);
6615 err = check_stack_read(env, regno, off, size,
6618 err = check_stack_write(env, regno, off, size,
6619 value_regno, insn_idx);
6620 } else if (reg_is_pkt_pointer(reg)) {
6621 if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
6622 verbose(env, "cannot write into packet\n");
6625 if (t == BPF_WRITE && value_regno >= 0 &&
6626 is_pointer_value(env, value_regno)) {
6627 verbose(env, "R%d leaks addr into packet\n",
6631 err = check_packet_access(env, regno, off, size, false);
6632 if (!err && t == BPF_READ && value_regno >= 0)
6633 mark_reg_unknown(env, regs, value_regno);
6634 } else if (reg->type == PTR_TO_FLOW_KEYS) {
6635 if (t == BPF_WRITE && value_regno >= 0 &&
6636 is_pointer_value(env, value_regno)) {
6637 verbose(env, "R%d leaks addr into flow keys\n",
6642 err = check_flow_keys_access(env, off, size);
6643 if (!err && t == BPF_READ && value_regno >= 0)
6644 mark_reg_unknown(env, regs, value_regno);
6645 } else if (type_is_sk_pointer(reg->type)) {
6646 if (t == BPF_WRITE) {
6647 verbose(env, "R%d cannot write into %s\n",
6648 regno, reg_type_str(env, reg->type));
6651 err = check_sock_access(env, insn_idx, regno, off, size, t);
6652 if (!err && value_regno >= 0)
6653 mark_reg_unknown(env, regs, value_regno);
6654 } else if (reg->type == PTR_TO_TP_BUFFER) {
6655 err = check_tp_buffer_access(env, reg, regno, off, size);
6656 if (!err && t == BPF_READ && value_regno >= 0)
6657 mark_reg_unknown(env, regs, value_regno);
6658 } else if (base_type(reg->type) == PTR_TO_BTF_ID &&
6659 !type_may_be_null(reg->type)) {
6660 err = check_ptr_to_btf_access(env, regs, regno, off, size, t,
6662 } else if (reg->type == CONST_PTR_TO_MAP) {
6663 err = check_ptr_to_map_access(env, regs, regno, off, size, t,
6665 } else if (base_type(reg->type) == PTR_TO_BUF) {
6666 bool rdonly_mem = type_is_rdonly_mem(reg->type);
6670 if (t == BPF_WRITE) {
6671 verbose(env, "R%d cannot write into %s\n",
6672 regno, reg_type_str(env, reg->type));
6675 max_access = &env->prog->aux->max_rdonly_access;
6677 max_access = &env->prog->aux->max_rdwr_access;
6680 err = check_buffer_access(env, reg, regno, off, size, false,
6683 if (!err && value_regno >= 0 && (rdonly_mem || t == BPF_READ))
6684 mark_reg_unknown(env, regs, value_regno);
6686 verbose(env, "R%d invalid mem access '%s'\n", regno,
6687 reg_type_str(env, reg->type));
6691 if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
6692 regs[value_regno].type == SCALAR_VALUE) {
6694 /* b/h/w load zero-extends, mark upper bits as known 0 */
6695 coerce_reg_to_size(®s[value_regno], size);
6697 coerce_reg_to_size_sx(®s[value_regno], size);
6702 static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn)
6707 switch (insn->imm) {
6709 case BPF_ADD | BPF_FETCH:
6711 case BPF_AND | BPF_FETCH:
6713 case BPF_OR | BPF_FETCH:
6715 case BPF_XOR | BPF_FETCH:
6720 verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm);
6724 if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) {
6725 verbose(env, "invalid atomic operand size\n");
6729 /* check src1 operand */
6730 err = check_reg_arg(env, insn->src_reg, SRC_OP);
6734 /* check src2 operand */
6735 err = check_reg_arg(env, insn->dst_reg, SRC_OP);
6739 if (insn->imm == BPF_CMPXCHG) {
6740 /* Check comparison of R0 with memory location */
6741 const u32 aux_reg = BPF_REG_0;
6743 err = check_reg_arg(env, aux_reg, SRC_OP);
6747 if (is_pointer_value(env, aux_reg)) {
6748 verbose(env, "R%d leaks addr into mem\n", aux_reg);
6753 if (is_pointer_value(env, insn->src_reg)) {
6754 verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
6758 if (is_ctx_reg(env, insn->dst_reg) ||
6759 is_pkt_reg(env, insn->dst_reg) ||
6760 is_flow_key_reg(env, insn->dst_reg) ||
6761 is_sk_reg(env, insn->dst_reg)) {
6762 verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
6764 reg_type_str(env, reg_state(env, insn->dst_reg)->type));
6768 if (insn->imm & BPF_FETCH) {
6769 if (insn->imm == BPF_CMPXCHG)
6770 load_reg = BPF_REG_0;
6772 load_reg = insn->src_reg;
6774 /* check and record load of old value */
6775 err = check_reg_arg(env, load_reg, DST_OP);
6779 /* This instruction accesses a memory location but doesn't
6780 * actually load it into a register.
6785 /* Check whether we can read the memory, with second call for fetch
6786 * case to simulate the register fill.
6788 err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
6789 BPF_SIZE(insn->code), BPF_READ, -1, true, false);
6790 if (!err && load_reg >= 0)
6791 err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
6792 BPF_SIZE(insn->code), BPF_READ, load_reg,
6797 /* Check whether we can write into the same memory. */
6798 err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
6799 BPF_SIZE(insn->code), BPF_WRITE, -1, true, false);
6806 /* When register 'regno' is used to read the stack (either directly or through
6807 * a helper function) make sure that it's within stack boundary and, depending
6808 * on the access type, that all elements of the stack are initialized.
6810 * 'off' includes 'regno->off', but not its dynamic part (if any).
6812 * All registers that have been spilled on the stack in the slots within the
6813 * read offsets are marked as read.
6815 static int check_stack_range_initialized(
6816 struct bpf_verifier_env *env, int regno, int off,
6817 int access_size, bool zero_size_allowed,
6818 enum bpf_access_src type, struct bpf_call_arg_meta *meta)
6820 struct bpf_reg_state *reg = reg_state(env, regno);
6821 struct bpf_func_state *state = func(env, reg);
6822 int err, min_off, max_off, i, j, slot, spi;
6823 char *err_extra = type == ACCESS_HELPER ? " indirect" : "";
6824 enum bpf_access_type bounds_check_type;
6825 /* Some accesses can write anything into the stack, others are
6828 bool clobber = false;
6830 if (access_size == 0 && !zero_size_allowed) {
6831 verbose(env, "invalid zero-sized read\n");
6835 if (type == ACCESS_HELPER) {
6836 /* The bounds checks for writes are more permissive than for
6837 * reads. However, if raw_mode is not set, we'll do extra
6840 bounds_check_type = BPF_WRITE;
6843 bounds_check_type = BPF_READ;
6845 err = check_stack_access_within_bounds(env, regno, off, access_size,
6846 type, bounds_check_type);
6851 if (tnum_is_const(reg->var_off)) {
6852 min_off = max_off = reg->var_off.value + off;
6854 /* Variable offset is prohibited for unprivileged mode for
6855 * simplicity since it requires corresponding support in
6856 * Spectre masking for stack ALU.
6857 * See also retrieve_ptr_limit().
6859 if (!env->bypass_spec_v1) {
6862 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
6863 verbose(env, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n",
6864 regno, err_extra, tn_buf);
6867 /* Only initialized buffer on stack is allowed to be accessed
6868 * with variable offset. With uninitialized buffer it's hard to
6869 * guarantee that whole memory is marked as initialized on
6870 * helper return since specific bounds are unknown what may
6871 * cause uninitialized stack leaking.
6873 if (meta && meta->raw_mode)
6876 min_off = reg->smin_value + off;
6877 max_off = reg->smax_value + off;
6880 if (meta && meta->raw_mode) {
6881 /* Ensure we won't be overwriting dynptrs when simulating byte
6882 * by byte access in check_helper_call using meta.access_size.
6883 * This would be a problem if we have a helper in the future
6886 * helper(uninit_mem, len, dynptr)
6888 * Now, uninint_mem may overlap with dynptr pointer. Hence, it
6889 * may end up writing to dynptr itself when touching memory from
6890 * arg 1. This can be relaxed on a case by case basis for known
6891 * safe cases, but reject due to the possibilitiy of aliasing by
6894 for (i = min_off; i < max_off + access_size; i++) {
6895 int stack_off = -i - 1;
6898 /* raw_mode may write past allocated_stack */
6899 if (state->allocated_stack <= stack_off)
6901 if (state->stack[spi].slot_type[stack_off % BPF_REG_SIZE] == STACK_DYNPTR) {
6902 verbose(env, "potential write to dynptr at off=%d disallowed\n", i);
6906 meta->access_size = access_size;
6907 meta->regno = regno;
6911 for (i = min_off; i < max_off + access_size; i++) {
6915 spi = slot / BPF_REG_SIZE;
6916 if (state->allocated_stack <= slot)
6918 stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
6919 if (*stype == STACK_MISC)
6921 if ((*stype == STACK_ZERO) ||
6922 (*stype == STACK_INVALID && env->allow_uninit_stack)) {
6924 /* helper can write anything into the stack */
6925 *stype = STACK_MISC;
6930 if (is_spilled_reg(&state->stack[spi]) &&
6931 (state->stack[spi].spilled_ptr.type == SCALAR_VALUE ||
6932 env->allow_ptr_leaks)) {
6934 __mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
6935 for (j = 0; j < BPF_REG_SIZE; j++)
6936 scrub_spilled_slot(&state->stack[spi].slot_type[j]);
6942 if (tnum_is_const(reg->var_off)) {
6943 verbose(env, "invalid%s read from stack R%d off %d+%d size %d\n",
6944 err_extra, regno, min_off, i - min_off, access_size);
6948 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
6949 verbose(env, "invalid%s read from stack R%d var_off %s+%d size %d\n",
6950 err_extra, regno, tn_buf, i - min_off, access_size);
6954 /* reading any byte out of 8-byte 'spill_slot' will cause
6955 * the whole slot to be marked as 'read'
6957 mark_reg_read(env, &state->stack[spi].spilled_ptr,
6958 state->stack[spi].spilled_ptr.parent,
6960 /* We do not set REG_LIVE_WRITTEN for stack slot, as we can not
6961 * be sure that whether stack slot is written to or not. Hence,
6962 * we must still conservatively propagate reads upwards even if
6963 * helper may write to the entire memory range.
6966 return update_stack_depth(env, state, min_off);
6969 static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
6970 int access_size, bool zero_size_allowed,
6971 struct bpf_call_arg_meta *meta)
6973 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
6976 switch (base_type(reg->type)) {
6978 case PTR_TO_PACKET_META:
6979 return check_packet_access(env, regno, reg->off, access_size,
6981 case PTR_TO_MAP_KEY:
6982 if (meta && meta->raw_mode) {
6983 verbose(env, "R%d cannot write into %s\n", regno,
6984 reg_type_str(env, reg->type));
6987 return check_mem_region_access(env, regno, reg->off, access_size,
6988 reg->map_ptr->key_size, false);
6989 case PTR_TO_MAP_VALUE:
6990 if (check_map_access_type(env, regno, reg->off, access_size,
6991 meta && meta->raw_mode ? BPF_WRITE :
6994 return check_map_access(env, regno, reg->off, access_size,
6995 zero_size_allowed, ACCESS_HELPER);
6997 if (type_is_rdonly_mem(reg->type)) {
6998 if (meta && meta->raw_mode) {
6999 verbose(env, "R%d cannot write into %s\n", regno,
7000 reg_type_str(env, reg->type));
7004 return check_mem_region_access(env, regno, reg->off,
7005 access_size, reg->mem_size,
7008 if (type_is_rdonly_mem(reg->type)) {
7009 if (meta && meta->raw_mode) {
7010 verbose(env, "R%d cannot write into %s\n", regno,
7011 reg_type_str(env, reg->type));
7015 max_access = &env->prog->aux->max_rdonly_access;
7017 max_access = &env->prog->aux->max_rdwr_access;
7019 return check_buffer_access(env, reg, regno, reg->off,
7020 access_size, zero_size_allowed,
7023 return check_stack_range_initialized(
7025 regno, reg->off, access_size,
7026 zero_size_allowed, ACCESS_HELPER, meta);
7028 return check_ptr_to_btf_access(env, regs, regno, reg->off,
7029 access_size, BPF_READ, -1);
7031 /* in case the function doesn't know how to access the context,
7032 * (because we are in a program of type SYSCALL for example), we
7033 * can not statically check its size.
7034 * Dynamically check it now.
7036 if (!env->ops->convert_ctx_access) {
7037 enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ;
7038 int offset = access_size - 1;
7040 /* Allow zero-byte read from PTR_TO_CTX */
7041 if (access_size == 0)
7042 return zero_size_allowed ? 0 : -EACCES;
7044 return check_mem_access(env, env->insn_idx, regno, offset, BPF_B,
7045 atype, -1, false, false);
7049 default: /* scalar_value or invalid ptr */
7050 /* Allow zero-byte read from NULL, regardless of pointer type */
7051 if (zero_size_allowed && access_size == 0 &&
7052 register_is_null(reg))
7055 verbose(env, "R%d type=%s ", regno,
7056 reg_type_str(env, reg->type));
7057 verbose(env, "expected=%s\n", reg_type_str(env, PTR_TO_STACK));
7062 static int check_mem_size_reg(struct bpf_verifier_env *env,
7063 struct bpf_reg_state *reg, u32 regno,
7064 bool zero_size_allowed,
7065 struct bpf_call_arg_meta *meta)
7069 /* This is used to refine r0 return value bounds for helpers
7070 * that enforce this value as an upper bound on return values.
7071 * See do_refine_retval_range() for helpers that can refine
7072 * the return value. C type of helper is u32 so we pull register
7073 * bound from umax_value however, if negative verifier errors
7074 * out. Only upper bounds can be learned because retval is an
7075 * int type and negative retvals are allowed.
7077 meta->msize_max_value = reg->umax_value;
7079 /* The register is SCALAR_VALUE; the access check
7080 * happens using its boundaries.
7082 if (!tnum_is_const(reg->var_off))
7083 /* For unprivileged variable accesses, disable raw
7084 * mode so that the program is required to
7085 * initialize all the memory that the helper could
7086 * just partially fill up.
7090 if (reg->smin_value < 0) {
7091 verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n",
7096 if (reg->umin_value == 0) {
7097 err = check_helper_mem_access(env, regno - 1, 0,
7104 if (reg->umax_value >= BPF_MAX_VAR_SIZ) {
7105 verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
7109 err = check_helper_mem_access(env, regno - 1,
7111 zero_size_allowed, meta);
7113 err = mark_chain_precision(env, regno);
7117 int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
7118 u32 regno, u32 mem_size)
7120 bool may_be_null = type_may_be_null(reg->type);
7121 struct bpf_reg_state saved_reg;
7122 struct bpf_call_arg_meta meta;
7125 if (register_is_null(reg))
7128 memset(&meta, 0, sizeof(meta));
7129 /* Assuming that the register contains a value check if the memory
7130 * access is safe. Temporarily save and restore the register's state as
7131 * the conversion shouldn't be visible to a caller.
7135 mark_ptr_not_null_reg(reg);
7138 err = check_helper_mem_access(env, regno, mem_size, true, &meta);
7139 /* Check access for BPF_WRITE */
7140 meta.raw_mode = true;
7141 err = err ?: check_helper_mem_access(env, regno, mem_size, true, &meta);
7149 static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
7152 struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
7153 bool may_be_null = type_may_be_null(mem_reg->type);
7154 struct bpf_reg_state saved_reg;
7155 struct bpf_call_arg_meta meta;
7158 WARN_ON_ONCE(regno < BPF_REG_2 || regno > BPF_REG_5);
7160 memset(&meta, 0, sizeof(meta));
7163 saved_reg = *mem_reg;
7164 mark_ptr_not_null_reg(mem_reg);
7167 err = check_mem_size_reg(env, reg, regno, true, &meta);
7168 /* Check access for BPF_WRITE */
7169 meta.raw_mode = true;
7170 err = err ?: check_mem_size_reg(env, reg, regno, true, &meta);
7173 *mem_reg = saved_reg;
7177 /* Implementation details:
7178 * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL.
7179 * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL.
7180 * Two bpf_map_lookups (even with the same key) will have different reg->id.
7181 * Two separate bpf_obj_new will also have different reg->id.
7182 * For traditional PTR_TO_MAP_VALUE or PTR_TO_BTF_ID | MEM_ALLOC, the verifier
7183 * clears reg->id after value_or_null->value transition, since the verifier only
7184 * cares about the range of access to valid map value pointer and doesn't care
7185 * about actual address of the map element.
7186 * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
7187 * reg->id > 0 after value_or_null->value transition. By doing so
7188 * two bpf_map_lookups will be considered two different pointers that
7189 * point to different bpf_spin_locks. Likewise for pointers to allocated objects
7190 * returned from bpf_obj_new.
7191 * The verifier allows taking only one bpf_spin_lock at a time to avoid
7193 * Since only one bpf_spin_lock is allowed the checks are simpler than
7194 * reg_is_refcounted() logic. The verifier needs to remember only
7195 * one spin_lock instead of array of acquired_refs.
7196 * cur_state->active_lock remembers which map value element or allocated
7197 * object got locked and clears it after bpf_spin_unlock.
7199 static int process_spin_lock(struct bpf_verifier_env *env, int regno,
7202 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
7203 struct bpf_verifier_state *cur = env->cur_state;
7204 bool is_const = tnum_is_const(reg->var_off);
7205 u64 val = reg->var_off.value;
7206 struct bpf_map *map = NULL;
7207 struct btf *btf = NULL;
7208 struct btf_record *rec;
7212 "R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
7216 if (reg->type == PTR_TO_MAP_VALUE) {
7220 "map '%s' has to have BTF in order to use bpf_spin_lock\n",
7228 rec = reg_btf_record(reg);
7229 if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) {
7230 verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local",
7231 map ? map->name : "kptr");
7234 if (rec->spin_lock_off != val + reg->off) {
7235 verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n",
7236 val + reg->off, rec->spin_lock_off);
7240 if (cur->active_lock.ptr) {
7242 "Locking two bpf_spin_locks are not allowed\n");
7246 cur->active_lock.ptr = map;
7248 cur->active_lock.ptr = btf;
7249 cur->active_lock.id = reg->id;
7258 if (!cur->active_lock.ptr) {
7259 verbose(env, "bpf_spin_unlock without taking a lock\n");
7262 if (cur->active_lock.ptr != ptr ||
7263 cur->active_lock.id != reg->id) {
7264 verbose(env, "bpf_spin_unlock of different lock\n");
7268 invalidate_non_owning_refs(env);
7270 cur->active_lock.ptr = NULL;
7271 cur->active_lock.id = 0;
7276 static int process_timer_func(struct bpf_verifier_env *env, int regno,
7277 struct bpf_call_arg_meta *meta)
7279 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
7280 bool is_const = tnum_is_const(reg->var_off);
7281 struct bpf_map *map = reg->map_ptr;
7282 u64 val = reg->var_off.value;
7286 "R%d doesn't have constant offset. bpf_timer has to be at the constant offset\n",
7291 verbose(env, "map '%s' has to have BTF in order to use bpf_timer\n",
7295 if (!btf_record_has_field(map->record, BPF_TIMER)) {
7296 verbose(env, "map '%s' has no valid bpf_timer\n", map->name);
7299 if (map->record->timer_off != val + reg->off) {
7300 verbose(env, "off %lld doesn't point to 'struct bpf_timer' that is at %d\n",
7301 val + reg->off, map->record->timer_off);
7304 if (meta->map_ptr) {
7305 verbose(env, "verifier bug. Two map pointers in a timer helper\n");
7308 meta->map_uid = reg->map_uid;
7309 meta->map_ptr = map;
7313 static int process_kptr_func(struct bpf_verifier_env *env, int regno,
7314 struct bpf_call_arg_meta *meta)
7316 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
7317 struct bpf_map *map_ptr = reg->map_ptr;
7318 struct btf_field *kptr_field;
7321 if (!tnum_is_const(reg->var_off)) {
7323 "R%d doesn't have constant offset. kptr has to be at the constant offset\n",
7327 if (!map_ptr->btf) {
7328 verbose(env, "map '%s' has to have BTF in order to use bpf_kptr_xchg\n",
7332 if (!btf_record_has_field(map_ptr->record, BPF_KPTR)) {
7333 verbose(env, "map '%s' has no valid kptr\n", map_ptr->name);
7337 meta->map_ptr = map_ptr;
7338 kptr_off = reg->off + reg->var_off.value;
7339 kptr_field = btf_record_find(map_ptr->record, kptr_off, BPF_KPTR);
7341 verbose(env, "off=%d doesn't point to kptr\n", kptr_off);
7344 if (kptr_field->type != BPF_KPTR_REF) {
7345 verbose(env, "off=%d kptr isn't referenced kptr\n", kptr_off);
7348 meta->kptr_field = kptr_field;
7352 /* There are two register types representing a bpf_dynptr, one is PTR_TO_STACK
7353 * which points to a stack slot, and the other is CONST_PTR_TO_DYNPTR.
7355 * In both cases we deal with the first 8 bytes, but need to mark the next 8
7356 * bytes as STACK_DYNPTR in case of PTR_TO_STACK. In case of
7357 * CONST_PTR_TO_DYNPTR, we are guaranteed to get the beginning of the object.
7359 * Mutability of bpf_dynptr is at two levels, one is at the level of struct
7360 * bpf_dynptr itself, i.e. whether the helper is receiving a pointer to struct
7361 * bpf_dynptr or pointer to const struct bpf_dynptr. In the former case, it can
7362 * mutate the view of the dynptr and also possibly destroy it. In the latter
7363 * case, it cannot mutate the bpf_dynptr itself but it can still mutate the
7364 * memory that dynptr points to.
7366 * The verifier will keep track both levels of mutation (bpf_dynptr's in
7367 * reg->type and the memory's in reg->dynptr.type), but there is no support for
7368 * readonly dynptr view yet, hence only the first case is tracked and checked.
7370 * This is consistent with how C applies the const modifier to a struct object,
7371 * where the pointer itself inside bpf_dynptr becomes const but not what it
7374 * Helpers which do not mutate the bpf_dynptr set MEM_RDONLY in their argument
7375 * type, and declare it as 'const struct bpf_dynptr *' in their prototype.
7377 static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx,
7378 enum bpf_arg_type arg_type, int clone_ref_obj_id)
7380 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
7383 /* MEM_UNINIT and MEM_RDONLY are exclusive, when applied to an
7384 * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*):
7386 if ((arg_type & (MEM_UNINIT | MEM_RDONLY)) == (MEM_UNINIT | MEM_RDONLY)) {
7387 verbose(env, "verifier internal error: misconfigured dynptr helper type flags\n");
7391 /* MEM_UNINIT - Points to memory that is an appropriate candidate for
7392 * constructing a mutable bpf_dynptr object.
7394 * Currently, this is only possible with PTR_TO_STACK
7395 * pointing to a region of at least 16 bytes which doesn't
7396 * contain an existing bpf_dynptr.
7398 * MEM_RDONLY - Points to a initialized bpf_dynptr that will not be
7399 * mutated or destroyed. However, the memory it points to
7402 * None - Points to a initialized dynptr that can be mutated and
7403 * destroyed, including mutation of the memory it points
7406 if (arg_type & MEM_UNINIT) {
7409 if (!is_dynptr_reg_valid_uninit(env, reg)) {
7410 verbose(env, "Dynptr has to be an uninitialized dynptr\n");
7414 /* we write BPF_DW bits (8 bytes) at a time */
7415 for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) {
7416 err = check_mem_access(env, insn_idx, regno,
7417 i, BPF_DW, BPF_WRITE, -1, false, false);
7422 err = mark_stack_slots_dynptr(env, reg, arg_type, insn_idx, clone_ref_obj_id);
7423 } else /* MEM_RDONLY and None case from above */ {
7424 /* For the reg->type == PTR_TO_STACK case, bpf_dynptr is never const */
7425 if (reg->type == CONST_PTR_TO_DYNPTR && !(arg_type & MEM_RDONLY)) {
7426 verbose(env, "cannot pass pointer to const bpf_dynptr, the helper mutates it\n");
7430 if (!is_dynptr_reg_valid_init(env, reg)) {
7432 "Expected an initialized dynptr as arg #%d\n",
7437 /* Fold modifiers (in this case, MEM_RDONLY) when checking expected type */
7438 if (!is_dynptr_type_expected(env, reg, arg_type & ~MEM_RDONLY)) {
7440 "Expected a dynptr of type %s as arg #%d\n",
7441 dynptr_type_str(arg_to_dynptr_type(arg_type)), regno);
7445 err = mark_dynptr_read(env, reg);
7450 static u32 iter_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int spi)
7452 struct bpf_func_state *state = func(env, reg);
7454 return state->stack[spi].spilled_ptr.ref_obj_id;
7457 static bool is_iter_kfunc(struct bpf_kfunc_call_arg_meta *meta)
7459 return meta->kfunc_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
7462 static bool is_iter_new_kfunc(struct bpf_kfunc_call_arg_meta *meta)
7464 return meta->kfunc_flags & KF_ITER_NEW;
7467 static bool is_iter_next_kfunc(struct bpf_kfunc_call_arg_meta *meta)
7469 return meta->kfunc_flags & KF_ITER_NEXT;
7472 static bool is_iter_destroy_kfunc(struct bpf_kfunc_call_arg_meta *meta)
7474 return meta->kfunc_flags & KF_ITER_DESTROY;
7477 static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg)
7479 /* btf_check_iter_kfuncs() guarantees that first argument of any iter
7480 * kfunc is iter state pointer
7482 return arg == 0 && is_iter_kfunc(meta);
7485 static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_idx,
7486 struct bpf_kfunc_call_arg_meta *meta)
7488 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
7489 const struct btf_type *t;
7490 const struct btf_param *arg;
7491 int spi, err, i, nr_slots;
7494 /* btf_check_iter_kfuncs() ensures we don't need to validate anything here */
7495 arg = &btf_params(meta->func_proto)[0];
7496 t = btf_type_skip_modifiers(meta->btf, arg->type, NULL); /* PTR */
7497 t = btf_type_skip_modifiers(meta->btf, t->type, &btf_id); /* STRUCT */
7498 nr_slots = t->size / BPF_REG_SIZE;
7500 if (is_iter_new_kfunc(meta)) {
7501 /* bpf_iter_<type>_new() expects pointer to uninit iter state */
7502 if (!is_iter_reg_valid_uninit(env, reg, nr_slots)) {
7503 verbose(env, "expected uninitialized iter_%s as arg #%d\n",
7504 iter_type_str(meta->btf, btf_id), regno);
7508 for (i = 0; i < nr_slots * 8; i += BPF_REG_SIZE) {
7509 err = check_mem_access(env, insn_idx, regno,
7510 i, BPF_DW, BPF_WRITE, -1, false, false);
7515 err = mark_stack_slots_iter(env, reg, insn_idx, meta->btf, btf_id, nr_slots);
7519 /* iter_next() or iter_destroy() expect initialized iter state*/
7520 if (!is_iter_reg_valid_init(env, reg, meta->btf, btf_id, nr_slots)) {
7521 verbose(env, "expected an initialized iter_%s as arg #%d\n",
7522 iter_type_str(meta->btf, btf_id), regno);
7526 spi = iter_get_spi(env, reg, nr_slots);
7530 err = mark_iter_read(env, reg, spi, nr_slots);
7534 /* remember meta->iter info for process_iter_next_call() */
7535 meta->iter.spi = spi;
7536 meta->iter.frameno = reg->frameno;
7537 meta->ref_obj_id = iter_ref_obj_id(env, reg, spi);
7539 if (is_iter_destroy_kfunc(meta)) {
7540 err = unmark_stack_slots_iter(env, reg, nr_slots);
7549 /* process_iter_next_call() is called when verifier gets to iterator's next
7550 * "method" (e.g., bpf_iter_num_next() for numbers iterator) call. We'll refer
7551 * to it as just "iter_next()" in comments below.
7553 * BPF verifier relies on a crucial contract for any iter_next()
7554 * implementation: it should *eventually* return NULL, and once that happens
7555 * it should keep returning NULL. That is, once iterator exhausts elements to
7556 * iterate, it should never reset or spuriously return new elements.
7558 * With the assumption of such contract, process_iter_next_call() simulates
7559 * a fork in the verifier state to validate loop logic correctness and safety
7560 * without having to simulate infinite amount of iterations.
7562 * In current state, we first assume that iter_next() returned NULL and
7563 * iterator state is set to DRAINED (BPF_ITER_STATE_DRAINED). In such
7564 * conditions we should not form an infinite loop and should eventually reach
7567 * Besides that, we also fork current state and enqueue it for later
7568 * verification. In a forked state we keep iterator state as ACTIVE
7569 * (BPF_ITER_STATE_ACTIVE) and assume non-NULL return from iter_next(). We
7570 * also bump iteration depth to prevent erroneous infinite loop detection
7571 * later on (see iter_active_depths_differ() comment for details). In this
7572 * state we assume that we'll eventually loop back to another iter_next()
7573 * calls (it could be in exactly same location or in some other instruction,
7574 * it doesn't matter, we don't make any unnecessary assumptions about this,
7575 * everything revolves around iterator state in a stack slot, not which
7576 * instruction is calling iter_next()). When that happens, we either will come
7577 * to iter_next() with equivalent state and can conclude that next iteration
7578 * will proceed in exactly the same way as we just verified, so it's safe to
7579 * assume that loop converges. If not, we'll go on another iteration
7580 * simulation with a different input state, until all possible starting states
7581 * are validated or we reach maximum number of instructions limit.
7583 * This way, we will either exhaustively discover all possible input states
7584 * that iterator loop can start with and eventually will converge, or we'll
7585 * effectively regress into bounded loop simulation logic and either reach
7586 * maximum number of instructions if loop is not provably convergent, or there
7587 * is some statically known limit on number of iterations (e.g., if there is
7588 * an explicit `if n > 100 then break;` statement somewhere in the loop).
7590 * One very subtle but very important aspect is that we *always* simulate NULL
7591 * condition first (as the current state) before we simulate non-NULL case.
7592 * This has to do with intricacies of scalar precision tracking. By simulating
7593 * "exit condition" of iter_next() returning NULL first, we make sure all the
7594 * relevant precision marks *that will be set **after** we exit iterator loop*
7595 * are propagated backwards to common parent state of NULL and non-NULL
7596 * branches. Thanks to that, state equivalence checks done later in forked
7597 * state, when reaching iter_next() for ACTIVE iterator, can assume that
7598 * precision marks are finalized and won't change. Because simulating another
7599 * ACTIVE iterator iteration won't change them (because given same input
7600 * states we'll end up with exactly same output states which we are currently
7601 * comparing; and verification after the loop already propagated back what
7602 * needs to be **additionally** tracked as precise). It's subtle, grok
7603 * precision tracking for more intuitive understanding.
7605 static int process_iter_next_call(struct bpf_verifier_env *env, int insn_idx,
7606 struct bpf_kfunc_call_arg_meta *meta)
7608 struct bpf_verifier_state *cur_st = env->cur_state, *queued_st;
7609 struct bpf_func_state *cur_fr = cur_st->frame[cur_st->curframe], *queued_fr;
7610 struct bpf_reg_state *cur_iter, *queued_iter;
7611 int iter_frameno = meta->iter.frameno;
7612 int iter_spi = meta->iter.spi;
7614 BTF_TYPE_EMIT(struct bpf_iter);
7616 cur_iter = &env->cur_state->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
7618 if (cur_iter->iter.state != BPF_ITER_STATE_ACTIVE &&
7619 cur_iter->iter.state != BPF_ITER_STATE_DRAINED) {
7620 verbose(env, "verifier internal error: unexpected iterator state %d (%s)\n",
7621 cur_iter->iter.state, iter_state_str(cur_iter->iter.state));
7625 if (cur_iter->iter.state == BPF_ITER_STATE_ACTIVE) {
7626 /* branch out active iter state */
7627 queued_st = push_stack(env, insn_idx + 1, insn_idx, false);
7631 queued_iter = &queued_st->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
7632 queued_iter->iter.state = BPF_ITER_STATE_ACTIVE;
7633 queued_iter->iter.depth++;
7635 queued_fr = queued_st->frame[queued_st->curframe];
7636 mark_ptr_not_null_reg(&queued_fr->regs[BPF_REG_0]);
7639 /* switch to DRAINED state, but keep the depth unchanged */
7640 /* mark current iter state as drained and assume returned NULL */
7641 cur_iter->iter.state = BPF_ITER_STATE_DRAINED;
7642 __mark_reg_const_zero(&cur_fr->regs[BPF_REG_0]);
7647 static bool arg_type_is_mem_size(enum bpf_arg_type type)
7649 return type == ARG_CONST_SIZE ||
7650 type == ARG_CONST_SIZE_OR_ZERO;
7653 static bool arg_type_is_release(enum bpf_arg_type type)
7655 return type & OBJ_RELEASE;
7658 static bool arg_type_is_dynptr(enum bpf_arg_type type)
7660 return base_type(type) == ARG_PTR_TO_DYNPTR;
7663 static int int_ptr_type_to_size(enum bpf_arg_type type)
7665 if (type == ARG_PTR_TO_INT)
7667 else if (type == ARG_PTR_TO_LONG)
7673 static int resolve_map_arg_type(struct bpf_verifier_env *env,
7674 const struct bpf_call_arg_meta *meta,
7675 enum bpf_arg_type *arg_type)
7677 if (!meta->map_ptr) {
7678 /* kernel subsystem misconfigured verifier */
7679 verbose(env, "invalid map_ptr to access map->type\n");
7683 switch (meta->map_ptr->map_type) {
7684 case BPF_MAP_TYPE_SOCKMAP:
7685 case BPF_MAP_TYPE_SOCKHASH:
7686 if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
7687 *arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;
7689 verbose(env, "invalid arg_type for sockmap/sockhash\n");
7693 case BPF_MAP_TYPE_BLOOM_FILTER:
7694 if (meta->func_id == BPF_FUNC_map_peek_elem)
7695 *arg_type = ARG_PTR_TO_MAP_VALUE;
7703 struct bpf_reg_types {
7704 const enum bpf_reg_type types[10];
7708 static const struct bpf_reg_types sock_types = {
7718 static const struct bpf_reg_types btf_id_sock_common_types = {
7725 PTR_TO_BTF_ID | PTR_TRUSTED,
7727 .btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
7731 static const struct bpf_reg_types mem_types = {
7739 PTR_TO_MEM | MEM_RINGBUF,
7741 PTR_TO_BTF_ID | PTR_TRUSTED,
7745 static const struct bpf_reg_types int_ptr_types = {
7755 static const struct bpf_reg_types spin_lock_types = {
7758 PTR_TO_BTF_ID | MEM_ALLOC,
7762 static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
7763 static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
7764 static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
7765 static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } };
7766 static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
7767 static const struct bpf_reg_types btf_ptr_types = {
7770 PTR_TO_BTF_ID | PTR_TRUSTED,
7771 PTR_TO_BTF_ID | MEM_RCU,
7774 static const struct bpf_reg_types percpu_btf_ptr_types = {
7776 PTR_TO_BTF_ID | MEM_PERCPU,
7777 PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED,
7780 static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } };
7781 static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } };
7782 static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } };
7783 static const struct bpf_reg_types timer_types = { .types = { PTR_TO_MAP_VALUE } };
7784 static const struct bpf_reg_types kptr_types = { .types = { PTR_TO_MAP_VALUE } };
7785 static const struct bpf_reg_types dynptr_types = {
7788 CONST_PTR_TO_DYNPTR,
7792 static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
7793 [ARG_PTR_TO_MAP_KEY] = &mem_types,
7794 [ARG_PTR_TO_MAP_VALUE] = &mem_types,
7795 [ARG_CONST_SIZE] = &scalar_types,
7796 [ARG_CONST_SIZE_OR_ZERO] = &scalar_types,
7797 [ARG_CONST_ALLOC_SIZE_OR_ZERO] = &scalar_types,
7798 [ARG_CONST_MAP_PTR] = &const_map_ptr_types,
7799 [ARG_PTR_TO_CTX] = &context_types,
7800 [ARG_PTR_TO_SOCK_COMMON] = &sock_types,
7802 [ARG_PTR_TO_BTF_ID_SOCK_COMMON] = &btf_id_sock_common_types,
7804 [ARG_PTR_TO_SOCKET] = &fullsock_types,
7805 [ARG_PTR_TO_BTF_ID] = &btf_ptr_types,
7806 [ARG_PTR_TO_SPIN_LOCK] = &spin_lock_types,
7807 [ARG_PTR_TO_MEM] = &mem_types,
7808 [ARG_PTR_TO_RINGBUF_MEM] = &ringbuf_mem_types,
7809 [ARG_PTR_TO_INT] = &int_ptr_types,
7810 [ARG_PTR_TO_LONG] = &int_ptr_types,
7811 [ARG_PTR_TO_PERCPU_BTF_ID] = &percpu_btf_ptr_types,
7812 [ARG_PTR_TO_FUNC] = &func_ptr_types,
7813 [ARG_PTR_TO_STACK] = &stack_ptr_types,
7814 [ARG_PTR_TO_CONST_STR] = &const_str_ptr_types,
7815 [ARG_PTR_TO_TIMER] = &timer_types,
7816 [ARG_PTR_TO_KPTR] = &kptr_types,
7817 [ARG_PTR_TO_DYNPTR] = &dynptr_types,
7820 static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
7821 enum bpf_arg_type arg_type,
7822 const u32 *arg_btf_id,
7823 struct bpf_call_arg_meta *meta)
7825 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
7826 enum bpf_reg_type expected, type = reg->type;
7827 const struct bpf_reg_types *compatible;
7830 compatible = compatible_reg_types[base_type(arg_type)];
7832 verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type);
7836 /* ARG_PTR_TO_MEM + RDONLY is compatible with PTR_TO_MEM and PTR_TO_MEM + RDONLY,
7837 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM and NOT with PTR_TO_MEM + RDONLY
7839 * Same for MAYBE_NULL:
7841 * ARG_PTR_TO_MEM + MAYBE_NULL is compatible with PTR_TO_MEM and PTR_TO_MEM + MAYBE_NULL,
7842 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM but NOT with PTR_TO_MEM + MAYBE_NULL
7844 * ARG_PTR_TO_MEM is compatible with PTR_TO_MEM that is tagged with a dynptr type.
7846 * Therefore we fold these flags depending on the arg_type before comparison.
7848 if (arg_type & MEM_RDONLY)
7849 type &= ~MEM_RDONLY;
7850 if (arg_type & PTR_MAYBE_NULL)
7851 type &= ~PTR_MAYBE_NULL;
7852 if (base_type(arg_type) == ARG_PTR_TO_MEM)
7853 type &= ~DYNPTR_TYPE_FLAG_MASK;
7855 if (meta->func_id == BPF_FUNC_kptr_xchg && type_is_alloc(type))
7858 for (i = 0; i < ARRAY_SIZE(compatible->types); i++) {
7859 expected = compatible->types[i];
7860 if (expected == NOT_INIT)
7863 if (type == expected)
7867 verbose(env, "R%d type=%s expected=", regno, reg_type_str(env, reg->type));
7868 for (j = 0; j + 1 < i; j++)
7869 verbose(env, "%s, ", reg_type_str(env, compatible->types[j]));
7870 verbose(env, "%s\n", reg_type_str(env, compatible->types[j]));
7874 if (base_type(reg->type) != PTR_TO_BTF_ID)
7877 if (compatible == &mem_types) {
7878 if (!(arg_type & MEM_RDONLY)) {
7880 "%s() may write into memory pointed by R%d type=%s\n",
7881 func_id_name(meta->func_id),
7882 regno, reg_type_str(env, reg->type));
7888 switch ((int)reg->type) {
7890 case PTR_TO_BTF_ID | PTR_TRUSTED:
7891 case PTR_TO_BTF_ID | MEM_RCU:
7892 case PTR_TO_BTF_ID | PTR_MAYBE_NULL:
7893 case PTR_TO_BTF_ID | PTR_MAYBE_NULL | MEM_RCU:
7895 /* For bpf_sk_release, it needs to match against first member
7896 * 'struct sock_common', hence make an exception for it. This
7897 * allows bpf_sk_release to work for multiple socket types.
7899 bool strict_type_match = arg_type_is_release(arg_type) &&
7900 meta->func_id != BPF_FUNC_sk_release;
7902 if (type_may_be_null(reg->type) &&
7903 (!type_may_be_null(arg_type) || arg_type_is_release(arg_type))) {
7904 verbose(env, "Possibly NULL pointer passed to helper arg%d\n", regno);
7909 if (!compatible->btf_id) {
7910 verbose(env, "verifier internal error: missing arg compatible BTF ID\n");
7913 arg_btf_id = compatible->btf_id;
7916 if (meta->func_id == BPF_FUNC_kptr_xchg) {
7917 if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
7920 if (arg_btf_id == BPF_PTR_POISON) {
7921 verbose(env, "verifier internal error:");
7922 verbose(env, "R%d has non-overwritten BPF_PTR_POISON type\n",
7927 if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
7928 btf_vmlinux, *arg_btf_id,
7929 strict_type_match)) {
7930 verbose(env, "R%d is of type %s but %s is expected\n",
7931 regno, btf_type_name(reg->btf, reg->btf_id),
7932 btf_type_name(btf_vmlinux, *arg_btf_id));
7938 case PTR_TO_BTF_ID | MEM_ALLOC:
7939 if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock &&
7940 meta->func_id != BPF_FUNC_kptr_xchg) {
7941 verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n");
7944 if (meta->func_id == BPF_FUNC_kptr_xchg) {
7945 if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
7949 case PTR_TO_BTF_ID | MEM_PERCPU:
7950 case PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED:
7951 /* Handled by helper specific checks */
7954 verbose(env, "verifier internal error: invalid PTR_TO_BTF_ID register for type match\n");
7960 static struct btf_field *
7961 reg_find_field_offset(const struct bpf_reg_state *reg, s32 off, u32 fields)
7963 struct btf_field *field;
7964 struct btf_record *rec;
7966 rec = reg_btf_record(reg);
7970 field = btf_record_find(rec, off, fields);
7977 int check_func_arg_reg_off(struct bpf_verifier_env *env,
7978 const struct bpf_reg_state *reg, int regno,
7979 enum bpf_arg_type arg_type)
7981 u32 type = reg->type;
7983 /* When referenced register is passed to release function, its fixed
7986 * We will check arg_type_is_release reg has ref_obj_id when storing
7987 * meta->release_regno.
7989 if (arg_type_is_release(arg_type)) {
7990 /* ARG_PTR_TO_DYNPTR with OBJ_RELEASE is a bit special, as it
7991 * may not directly point to the object being released, but to
7992 * dynptr pointing to such object, which might be at some offset
7993 * on the stack. In that case, we simply to fallback to the
7996 if (arg_type_is_dynptr(arg_type) && type == PTR_TO_STACK)
7999 /* Doing check_ptr_off_reg check for the offset will catch this
8000 * because fixed_off_ok is false, but checking here allows us
8001 * to give the user a better error message.
8004 verbose(env, "R%d must have zero offset when passed to release func or trusted arg to kfunc\n",
8008 return __check_ptr_off_reg(env, reg, regno, false);
8012 /* Pointer types where both fixed and variable offset is explicitly allowed: */
8015 case PTR_TO_PACKET_META:
8016 case PTR_TO_MAP_KEY:
8017 case PTR_TO_MAP_VALUE:
8019 case PTR_TO_MEM | MEM_RDONLY:
8020 case PTR_TO_MEM | MEM_RINGBUF:
8022 case PTR_TO_BUF | MEM_RDONLY:
8025 /* All the rest must be rejected, except PTR_TO_BTF_ID which allows
8029 case PTR_TO_BTF_ID | MEM_ALLOC:
8030 case PTR_TO_BTF_ID | PTR_TRUSTED:
8031 case PTR_TO_BTF_ID | MEM_RCU:
8032 case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF:
8033 case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU:
8034 /* When referenced PTR_TO_BTF_ID is passed to release function,
8035 * its fixed offset must be 0. In the other cases, fixed offset
8036 * can be non-zero. This was already checked above. So pass
8037 * fixed_off_ok as true to allow fixed offset for all other
8038 * cases. var_off always must be 0 for PTR_TO_BTF_ID, hence we
8039 * still need to do checks instead of returning.
8041 return __check_ptr_off_reg(env, reg, regno, true);
8043 return __check_ptr_off_reg(env, reg, regno, false);
8047 static struct bpf_reg_state *get_dynptr_arg_reg(struct bpf_verifier_env *env,
8048 const struct bpf_func_proto *fn,
8049 struct bpf_reg_state *regs)
8051 struct bpf_reg_state *state = NULL;
8054 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
8055 if (arg_type_is_dynptr(fn->arg_type[i])) {
8057 verbose(env, "verifier internal error: multiple dynptr args\n");
8060 state = ®s[BPF_REG_1 + i];
8064 verbose(env, "verifier internal error: no dynptr arg found\n");
8069 static int dynptr_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
8071 struct bpf_func_state *state = func(env, reg);
8074 if (reg->type == CONST_PTR_TO_DYNPTR)
8076 spi = dynptr_get_spi(env, reg);
8079 return state->stack[spi].spilled_ptr.id;
8082 static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
8084 struct bpf_func_state *state = func(env, reg);
8087 if (reg->type == CONST_PTR_TO_DYNPTR)
8088 return reg->ref_obj_id;
8089 spi = dynptr_get_spi(env, reg);
8092 return state->stack[spi].spilled_ptr.ref_obj_id;
8095 static enum bpf_dynptr_type dynptr_get_type(struct bpf_verifier_env *env,
8096 struct bpf_reg_state *reg)
8098 struct bpf_func_state *state = func(env, reg);
8101 if (reg->type == CONST_PTR_TO_DYNPTR)
8102 return reg->dynptr.type;
8104 spi = __get_spi(reg->off);
8106 verbose(env, "verifier internal error: invalid spi when querying dynptr type\n");
8107 return BPF_DYNPTR_TYPE_INVALID;
8110 return state->stack[spi].spilled_ptr.dynptr.type;
8113 static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
8114 struct bpf_call_arg_meta *meta,
8115 const struct bpf_func_proto *fn,
8118 u32 regno = BPF_REG_1 + arg;
8119 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[regno];
8120 enum bpf_arg_type arg_type = fn->arg_type[arg];
8121 enum bpf_reg_type type = reg->type;
8122 u32 *arg_btf_id = NULL;
8125 if (arg_type == ARG_DONTCARE)
8128 err = check_reg_arg(env, regno, SRC_OP);
8132 if (arg_type == ARG_ANYTHING) {
8133 if (is_pointer_value(env, regno)) {
8134 verbose(env, "R%d leaks addr into helper function\n",
8141 if (type_is_pkt_pointer(type) &&
8142 !may_access_direct_pkt_data(env, meta, BPF_READ)) {
8143 verbose(env, "helper access to the packet is not allowed\n");
8147 if (base_type(arg_type) == ARG_PTR_TO_MAP_VALUE) {
8148 err = resolve_map_arg_type(env, meta, &arg_type);
8153 if (register_is_null(reg) && type_may_be_null(arg_type))
8154 /* A NULL register has a SCALAR_VALUE type, so skip
8157 goto skip_type_check;
8159 /* arg_btf_id and arg_size are in a union. */
8160 if (base_type(arg_type) == ARG_PTR_TO_BTF_ID ||
8161 base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK)
8162 arg_btf_id = fn->arg_btf_id[arg];
8164 err = check_reg_type(env, regno, arg_type, arg_btf_id, meta);
8168 err = check_func_arg_reg_off(env, reg, regno, arg_type);
8173 if (arg_type_is_release(arg_type)) {
8174 if (arg_type_is_dynptr(arg_type)) {
8175 struct bpf_func_state *state = func(env, reg);
8178 /* Only dynptr created on stack can be released, thus
8179 * the get_spi and stack state checks for spilled_ptr
8180 * should only be done before process_dynptr_func for
8183 if (reg->type == PTR_TO_STACK) {
8184 spi = dynptr_get_spi(env, reg);
8185 if (spi < 0 || !state->stack[spi].spilled_ptr.ref_obj_id) {
8186 verbose(env, "arg %d is an unacquired reference\n", regno);
8190 verbose(env, "cannot release unowned const bpf_dynptr\n");
8193 } else if (!reg->ref_obj_id && !register_is_null(reg)) {
8194 verbose(env, "R%d must be referenced when passed to release function\n",
8198 if (meta->release_regno) {
8199 verbose(env, "verifier internal error: more than one release argument\n");
8202 meta->release_regno = regno;
8205 if (reg->ref_obj_id) {
8206 if (meta->ref_obj_id) {
8207 verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
8208 regno, reg->ref_obj_id,
8212 meta->ref_obj_id = reg->ref_obj_id;
8215 switch (base_type(arg_type)) {
8216 case ARG_CONST_MAP_PTR:
8217 /* bpf_map_xxx(map_ptr) call: remember that map_ptr */
8218 if (meta->map_ptr) {
8219 /* Use map_uid (which is unique id of inner map) to reject:
8220 * inner_map1 = bpf_map_lookup_elem(outer_map, key1)
8221 * inner_map2 = bpf_map_lookup_elem(outer_map, key2)
8222 * if (inner_map1 && inner_map2) {
8223 * timer = bpf_map_lookup_elem(inner_map1);
8225 * // mismatch would have been allowed
8226 * bpf_timer_init(timer, inner_map2);
8229 * Comparing map_ptr is enough to distinguish normal and outer maps.
8231 if (meta->map_ptr != reg->map_ptr ||
8232 meta->map_uid != reg->map_uid) {
8234 "timer pointer in R1 map_uid=%d doesn't match map pointer in R2 map_uid=%d\n",
8235 meta->map_uid, reg->map_uid);
8239 meta->map_ptr = reg->map_ptr;
8240 meta->map_uid = reg->map_uid;
8242 case ARG_PTR_TO_MAP_KEY:
8243 /* bpf_map_xxx(..., map_ptr, ..., key) call:
8244 * check that [key, key + map->key_size) are within
8245 * stack limits and initialized
8247 if (!meta->map_ptr) {
8248 /* in function declaration map_ptr must come before
8249 * map_key, so that it's verified and known before
8250 * we have to check map_key here. Otherwise it means
8251 * that kernel subsystem misconfigured verifier
8253 verbose(env, "invalid map_ptr to access map->key\n");
8256 err = check_helper_mem_access(env, regno,
8257 meta->map_ptr->key_size, false,
8260 case ARG_PTR_TO_MAP_VALUE:
8261 if (type_may_be_null(arg_type) && register_is_null(reg))
8264 /* bpf_map_xxx(..., map_ptr, ..., value) call:
8265 * check [value, value + map->value_size) validity
8267 if (!meta->map_ptr) {
8268 /* kernel subsystem misconfigured verifier */
8269 verbose(env, "invalid map_ptr to access map->value\n");
8272 meta->raw_mode = arg_type & MEM_UNINIT;
8273 err = check_helper_mem_access(env, regno,
8274 meta->map_ptr->value_size, false,
8277 case ARG_PTR_TO_PERCPU_BTF_ID:
8279 verbose(env, "Helper has invalid btf_id in R%d\n", regno);
8282 meta->ret_btf = reg->btf;
8283 meta->ret_btf_id = reg->btf_id;
8285 case ARG_PTR_TO_SPIN_LOCK:
8286 if (in_rbtree_lock_required_cb(env)) {
8287 verbose(env, "can't spin_{lock,unlock} in rbtree cb\n");
8290 if (meta->func_id == BPF_FUNC_spin_lock) {
8291 err = process_spin_lock(env, regno, true);
8294 } else if (meta->func_id == BPF_FUNC_spin_unlock) {
8295 err = process_spin_lock(env, regno, false);
8299 verbose(env, "verifier internal error\n");
8303 case ARG_PTR_TO_TIMER:
8304 err = process_timer_func(env, regno, meta);
8308 case ARG_PTR_TO_FUNC:
8309 meta->subprogno = reg->subprogno;
8311 case ARG_PTR_TO_MEM:
8312 /* The access to this pointer is only checked when we hit the
8313 * next is_mem_size argument below.
8315 meta->raw_mode = arg_type & MEM_UNINIT;
8316 if (arg_type & MEM_FIXED_SIZE) {
8317 err = check_helper_mem_access(env, regno,
8318 fn->arg_size[arg], false,
8322 case ARG_CONST_SIZE:
8323 err = check_mem_size_reg(env, reg, regno, false, meta);
8325 case ARG_CONST_SIZE_OR_ZERO:
8326 err = check_mem_size_reg(env, reg, regno, true, meta);
8328 case ARG_PTR_TO_DYNPTR:
8329 err = process_dynptr_func(env, regno, insn_idx, arg_type, 0);
8333 case ARG_CONST_ALLOC_SIZE_OR_ZERO:
8334 if (!tnum_is_const(reg->var_off)) {
8335 verbose(env, "R%d is not a known constant'\n",
8339 meta->mem_size = reg->var_off.value;
8340 err = mark_chain_precision(env, regno);
8344 case ARG_PTR_TO_INT:
8345 case ARG_PTR_TO_LONG:
8347 int size = int_ptr_type_to_size(arg_type);
8349 err = check_helper_mem_access(env, regno, size, false, meta);
8352 err = check_ptr_alignment(env, reg, 0, size, true);
8355 case ARG_PTR_TO_CONST_STR:
8357 struct bpf_map *map = reg->map_ptr;
8362 if (!bpf_map_is_rdonly(map)) {
8363 verbose(env, "R%d does not point to a readonly map'\n", regno);
8367 if (!tnum_is_const(reg->var_off)) {
8368 verbose(env, "R%d is not a constant address'\n", regno);
8372 if (!map->ops->map_direct_value_addr) {
8373 verbose(env, "no direct value access support for this map type\n");
8377 err = check_map_access(env, regno, reg->off,
8378 map->value_size - reg->off, false,
8383 map_off = reg->off + reg->var_off.value;
8384 err = map->ops->map_direct_value_addr(map, &map_addr, map_off);
8386 verbose(env, "direct value access on string failed\n");
8390 str_ptr = (char *)(long)(map_addr);
8391 if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) {
8392 verbose(env, "string is not zero-terminated\n");
8397 case ARG_PTR_TO_KPTR:
8398 err = process_kptr_func(env, regno, meta);
8407 static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
8409 enum bpf_attach_type eatype = env->prog->expected_attach_type;
8410 enum bpf_prog_type type = resolve_prog_type(env->prog);
8412 if (func_id != BPF_FUNC_map_update_elem)
8415 /* It's not possible to get access to a locked struct sock in these
8416 * contexts, so updating is safe.
8419 case BPF_PROG_TYPE_TRACING:
8420 if (eatype == BPF_TRACE_ITER)
8423 case BPF_PROG_TYPE_SOCKET_FILTER:
8424 case BPF_PROG_TYPE_SCHED_CLS:
8425 case BPF_PROG_TYPE_SCHED_ACT:
8426 case BPF_PROG_TYPE_XDP:
8427 case BPF_PROG_TYPE_SK_REUSEPORT:
8428 case BPF_PROG_TYPE_FLOW_DISSECTOR:
8429 case BPF_PROG_TYPE_SK_LOOKUP:
8435 verbose(env, "cannot update sockmap in this context\n");
8439 static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env)
8441 return env->prog->jit_requested &&
8442 bpf_jit_supports_subprog_tailcalls();
8445 static int check_map_func_compatibility(struct bpf_verifier_env *env,
8446 struct bpf_map *map, int func_id)
8451 /* We need a two way check, first is from map perspective ... */
8452 switch (map->map_type) {
8453 case BPF_MAP_TYPE_PROG_ARRAY:
8454 if (func_id != BPF_FUNC_tail_call)
8457 case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
8458 if (func_id != BPF_FUNC_perf_event_read &&
8459 func_id != BPF_FUNC_perf_event_output &&
8460 func_id != BPF_FUNC_skb_output &&
8461 func_id != BPF_FUNC_perf_event_read_value &&
8462 func_id != BPF_FUNC_xdp_output)
8465 case BPF_MAP_TYPE_RINGBUF:
8466 if (func_id != BPF_FUNC_ringbuf_output &&
8467 func_id != BPF_FUNC_ringbuf_reserve &&
8468 func_id != BPF_FUNC_ringbuf_query &&
8469 func_id != BPF_FUNC_ringbuf_reserve_dynptr &&
8470 func_id != BPF_FUNC_ringbuf_submit_dynptr &&
8471 func_id != BPF_FUNC_ringbuf_discard_dynptr)
8474 case BPF_MAP_TYPE_USER_RINGBUF:
8475 if (func_id != BPF_FUNC_user_ringbuf_drain)
8478 case BPF_MAP_TYPE_STACK_TRACE:
8479 if (func_id != BPF_FUNC_get_stackid)
8482 case BPF_MAP_TYPE_CGROUP_ARRAY:
8483 if (func_id != BPF_FUNC_skb_under_cgroup &&
8484 func_id != BPF_FUNC_current_task_under_cgroup)
8487 case BPF_MAP_TYPE_CGROUP_STORAGE:
8488 case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
8489 if (func_id != BPF_FUNC_get_local_storage)
8492 case BPF_MAP_TYPE_DEVMAP:
8493 case BPF_MAP_TYPE_DEVMAP_HASH:
8494 if (func_id != BPF_FUNC_redirect_map &&
8495 func_id != BPF_FUNC_map_lookup_elem)
8498 /* Restrict bpf side of cpumap and xskmap, open when use-cases
8501 case BPF_MAP_TYPE_CPUMAP:
8502 if (func_id != BPF_FUNC_redirect_map)
8505 case BPF_MAP_TYPE_XSKMAP:
8506 if (func_id != BPF_FUNC_redirect_map &&
8507 func_id != BPF_FUNC_map_lookup_elem)
8510 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
8511 case BPF_MAP_TYPE_HASH_OF_MAPS:
8512 if (func_id != BPF_FUNC_map_lookup_elem)
8515 case BPF_MAP_TYPE_SOCKMAP:
8516 if (func_id != BPF_FUNC_sk_redirect_map &&
8517 func_id != BPF_FUNC_sock_map_update &&
8518 func_id != BPF_FUNC_map_delete_elem &&
8519 func_id != BPF_FUNC_msg_redirect_map &&
8520 func_id != BPF_FUNC_sk_select_reuseport &&
8521 func_id != BPF_FUNC_map_lookup_elem &&
8522 !may_update_sockmap(env, func_id))
8525 case BPF_MAP_TYPE_SOCKHASH:
8526 if (func_id != BPF_FUNC_sk_redirect_hash &&
8527 func_id != BPF_FUNC_sock_hash_update &&
8528 func_id != BPF_FUNC_map_delete_elem &&
8529 func_id != BPF_FUNC_msg_redirect_hash &&
8530 func_id != BPF_FUNC_sk_select_reuseport &&
8531 func_id != BPF_FUNC_map_lookup_elem &&
8532 !may_update_sockmap(env, func_id))
8535 case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
8536 if (func_id != BPF_FUNC_sk_select_reuseport)
8539 case BPF_MAP_TYPE_QUEUE:
8540 case BPF_MAP_TYPE_STACK:
8541 if (func_id != BPF_FUNC_map_peek_elem &&
8542 func_id != BPF_FUNC_map_pop_elem &&
8543 func_id != BPF_FUNC_map_push_elem)
8546 case BPF_MAP_TYPE_SK_STORAGE:
8547 if (func_id != BPF_FUNC_sk_storage_get &&
8548 func_id != BPF_FUNC_sk_storage_delete &&
8549 func_id != BPF_FUNC_kptr_xchg)
8552 case BPF_MAP_TYPE_INODE_STORAGE:
8553 if (func_id != BPF_FUNC_inode_storage_get &&
8554 func_id != BPF_FUNC_inode_storage_delete &&
8555 func_id != BPF_FUNC_kptr_xchg)
8558 case BPF_MAP_TYPE_TASK_STORAGE:
8559 if (func_id != BPF_FUNC_task_storage_get &&
8560 func_id != BPF_FUNC_task_storage_delete &&
8561 func_id != BPF_FUNC_kptr_xchg)
8564 case BPF_MAP_TYPE_CGRP_STORAGE:
8565 if (func_id != BPF_FUNC_cgrp_storage_get &&
8566 func_id != BPF_FUNC_cgrp_storage_delete &&
8567 func_id != BPF_FUNC_kptr_xchg)
8570 case BPF_MAP_TYPE_BLOOM_FILTER:
8571 if (func_id != BPF_FUNC_map_peek_elem &&
8572 func_id != BPF_FUNC_map_push_elem)
8579 /* ... and second from the function itself. */
8581 case BPF_FUNC_tail_call:
8582 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
8584 if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) {
8585 verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
8589 case BPF_FUNC_perf_event_read:
8590 case BPF_FUNC_perf_event_output:
8591 case BPF_FUNC_perf_event_read_value:
8592 case BPF_FUNC_skb_output:
8593 case BPF_FUNC_xdp_output:
8594 if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
8597 case BPF_FUNC_ringbuf_output:
8598 case BPF_FUNC_ringbuf_reserve:
8599 case BPF_FUNC_ringbuf_query:
8600 case BPF_FUNC_ringbuf_reserve_dynptr:
8601 case BPF_FUNC_ringbuf_submit_dynptr:
8602 case BPF_FUNC_ringbuf_discard_dynptr:
8603 if (map->map_type != BPF_MAP_TYPE_RINGBUF)
8606 case BPF_FUNC_user_ringbuf_drain:
8607 if (map->map_type != BPF_MAP_TYPE_USER_RINGBUF)
8610 case BPF_FUNC_get_stackid:
8611 if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
8614 case BPF_FUNC_current_task_under_cgroup:
8615 case BPF_FUNC_skb_under_cgroup:
8616 if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
8619 case BPF_FUNC_redirect_map:
8620 if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
8621 map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
8622 map->map_type != BPF_MAP_TYPE_CPUMAP &&
8623 map->map_type != BPF_MAP_TYPE_XSKMAP)
8626 case BPF_FUNC_sk_redirect_map:
8627 case BPF_FUNC_msg_redirect_map:
8628 case BPF_FUNC_sock_map_update:
8629 if (map->map_type != BPF_MAP_TYPE_SOCKMAP)
8632 case BPF_FUNC_sk_redirect_hash:
8633 case BPF_FUNC_msg_redirect_hash:
8634 case BPF_FUNC_sock_hash_update:
8635 if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
8638 case BPF_FUNC_get_local_storage:
8639 if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
8640 map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
8643 case BPF_FUNC_sk_select_reuseport:
8644 if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
8645 map->map_type != BPF_MAP_TYPE_SOCKMAP &&
8646 map->map_type != BPF_MAP_TYPE_SOCKHASH)
8649 case BPF_FUNC_map_pop_elem:
8650 if (map->map_type != BPF_MAP_TYPE_QUEUE &&
8651 map->map_type != BPF_MAP_TYPE_STACK)
8654 case BPF_FUNC_map_peek_elem:
8655 case BPF_FUNC_map_push_elem:
8656 if (map->map_type != BPF_MAP_TYPE_QUEUE &&
8657 map->map_type != BPF_MAP_TYPE_STACK &&
8658 map->map_type != BPF_MAP_TYPE_BLOOM_FILTER)
8661 case BPF_FUNC_map_lookup_percpu_elem:
8662 if (map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY &&
8663 map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
8664 map->map_type != BPF_MAP_TYPE_LRU_PERCPU_HASH)
8667 case BPF_FUNC_sk_storage_get:
8668 case BPF_FUNC_sk_storage_delete:
8669 if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
8672 case BPF_FUNC_inode_storage_get:
8673 case BPF_FUNC_inode_storage_delete:
8674 if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
8677 case BPF_FUNC_task_storage_get:
8678 case BPF_FUNC_task_storage_delete:
8679 if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
8682 case BPF_FUNC_cgrp_storage_get:
8683 case BPF_FUNC_cgrp_storage_delete:
8684 if (map->map_type != BPF_MAP_TYPE_CGRP_STORAGE)
8693 verbose(env, "cannot pass map_type %d into func %s#%d\n",
8694 map->map_type, func_id_name(func_id), func_id);
8698 static bool check_raw_mode_ok(const struct bpf_func_proto *fn)
8702 if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM)
8704 if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM)
8706 if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM)
8708 if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM)
8710 if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM)
8713 /* We only support one arg being in raw mode at the moment,
8714 * which is sufficient for the helper functions we have
8720 static bool check_args_pair_invalid(const struct bpf_func_proto *fn, int arg)
8722 bool is_fixed = fn->arg_type[arg] & MEM_FIXED_SIZE;
8723 bool has_size = fn->arg_size[arg] != 0;
8724 bool is_next_size = false;
8726 if (arg + 1 < ARRAY_SIZE(fn->arg_type))
8727 is_next_size = arg_type_is_mem_size(fn->arg_type[arg + 1]);
8729 if (base_type(fn->arg_type[arg]) != ARG_PTR_TO_MEM)
8730 return is_next_size;
8732 return has_size == is_next_size || is_next_size == is_fixed;
8735 static bool check_arg_pair_ok(const struct bpf_func_proto *fn)
8737 /* bpf_xxx(..., buf, len) call will access 'len'
8738 * bytes from memory 'buf'. Both arg types need
8739 * to be paired, so make sure there's no buggy
8740 * helper function specification.
8742 if (arg_type_is_mem_size(fn->arg1_type) ||
8743 check_args_pair_invalid(fn, 0) ||
8744 check_args_pair_invalid(fn, 1) ||
8745 check_args_pair_invalid(fn, 2) ||
8746 check_args_pair_invalid(fn, 3) ||
8747 check_args_pair_invalid(fn, 4))
8753 static bool check_btf_id_ok(const struct bpf_func_proto *fn)
8757 for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
8758 if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID)
8759 return !!fn->arg_btf_id[i];
8760 if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK)
8761 return fn->arg_btf_id[i] == BPF_PTR_POISON;
8762 if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] &&
8763 /* arg_btf_id and arg_size are in a union. */
8764 (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||
8765 !(fn->arg_type[i] & MEM_FIXED_SIZE)))
8772 static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
8774 return check_raw_mode_ok(fn) &&
8775 check_arg_pair_ok(fn) &&
8776 check_btf_id_ok(fn) ? 0 : -EINVAL;
8779 /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
8780 * are now invalid, so turn them into unknown SCALAR_VALUE.
8782 * This also applies to dynptr slices belonging to skb and xdp dynptrs,
8783 * since these slices point to packet data.
8785 static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
8787 struct bpf_func_state *state;
8788 struct bpf_reg_state *reg;
8790 bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
8791 if (reg_is_pkt_pointer_any(reg) || reg_is_dynptr_slice_pkt(reg))
8792 mark_reg_invalid(env, reg);
8798 BEYOND_PKT_END = -2,
8801 static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open)
8803 struct bpf_func_state *state = vstate->frame[vstate->curframe];
8804 struct bpf_reg_state *reg = &state->regs[regn];
8806 if (reg->type != PTR_TO_PACKET)
8807 /* PTR_TO_PACKET_META is not supported yet */
8810 /* The 'reg' is pkt > pkt_end or pkt >= pkt_end.
8811 * How far beyond pkt_end it goes is unknown.
8812 * if (!range_open) it's the case of pkt >= pkt_end
8813 * if (range_open) it's the case of pkt > pkt_end
8814 * hence this pointer is at least 1 byte bigger than pkt_end
8817 reg->range = BEYOND_PKT_END;
8819 reg->range = AT_PKT_END;
8822 /* The pointer with the specified id has released its reference to kernel
8823 * resources. Identify all copies of the same pointer and clear the reference.
8825 static int release_reference(struct bpf_verifier_env *env,
8828 struct bpf_func_state *state;
8829 struct bpf_reg_state *reg;
8832 err = release_reference_state(cur_func(env), ref_obj_id);
8836 bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
8837 if (reg->ref_obj_id == ref_obj_id)
8838 mark_reg_invalid(env, reg);
8844 static void invalidate_non_owning_refs(struct bpf_verifier_env *env)
8846 struct bpf_func_state *unused;
8847 struct bpf_reg_state *reg;
8849 bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
8850 if (type_is_non_owning_ref(reg->type))
8851 mark_reg_invalid(env, reg);
8855 static void clear_caller_saved_regs(struct bpf_verifier_env *env,
8856 struct bpf_reg_state *regs)
8860 /* after the call registers r0 - r5 were scratched */
8861 for (i = 0; i < CALLER_SAVED_REGS; i++) {
8862 mark_reg_not_init(env, regs, caller_saved[i]);
8863 check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
8867 typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env,
8868 struct bpf_func_state *caller,
8869 struct bpf_func_state *callee,
8872 static int set_callee_state(struct bpf_verifier_env *env,
8873 struct bpf_func_state *caller,
8874 struct bpf_func_state *callee, int insn_idx);
8876 static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
8877 int *insn_idx, int subprog,
8878 set_callee_state_fn set_callee_state_cb)
8880 struct bpf_verifier_state *state = env->cur_state;
8881 struct bpf_func_state *caller, *callee;
8884 if (state->curframe + 1 >= MAX_CALL_FRAMES) {
8885 verbose(env, "the call stack of %d frames is too deep\n",
8886 state->curframe + 2);
8890 caller = state->frame[state->curframe];
8891 if (state->frame[state->curframe + 1]) {
8892 verbose(env, "verifier bug. Frame %d already allocated\n",
8893 state->curframe + 1);
8897 err = btf_check_subprog_call(env, subprog, caller->regs);
8900 if (subprog_is_global(env, subprog)) {
8902 verbose(env, "Caller passes invalid args into func#%d\n",
8906 if (env->log.level & BPF_LOG_LEVEL)
8908 "Func#%d is global and valid. Skipping.\n",
8910 clear_caller_saved_regs(env, caller->regs);
8912 /* All global functions return a 64-bit SCALAR_VALUE */
8913 mark_reg_unknown(env, caller->regs, BPF_REG_0);
8914 caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
8916 /* continue with next insn after call */
8921 /* set_callee_state is used for direct subprog calls, but we are
8922 * interested in validating only BPF helpers that can call subprogs as
8925 if (set_callee_state_cb != set_callee_state) {
8926 if (bpf_pseudo_kfunc_call(insn) &&
8927 !is_callback_calling_kfunc(insn->imm)) {
8928 verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
8929 func_id_name(insn->imm), insn->imm);
8931 } else if (!bpf_pseudo_kfunc_call(insn) &&
8932 !is_callback_calling_function(insn->imm)) { /* helper */
8933 verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
8934 func_id_name(insn->imm), insn->imm);
8939 if (insn->code == (BPF_JMP | BPF_CALL) &&
8940 insn->src_reg == 0 &&
8941 insn->imm == BPF_FUNC_timer_set_callback) {
8942 struct bpf_verifier_state *async_cb;
8944 /* there is no real recursion here. timer callbacks are async */
8945 env->subprog_info[subprog].is_async_cb = true;
8946 async_cb = push_async_cb(env, env->subprog_info[subprog].start,
8947 *insn_idx, subprog);
8950 callee = async_cb->frame[0];
8951 callee->async_entry_cnt = caller->async_entry_cnt + 1;
8953 /* Convert bpf_timer_set_callback() args into timer callback args */
8954 err = set_callee_state_cb(env, caller, callee, *insn_idx);
8958 clear_caller_saved_regs(env, caller->regs);
8959 mark_reg_unknown(env, caller->regs, BPF_REG_0);
8960 caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
8961 /* continue with next insn after call */
8965 callee = kzalloc(sizeof(*callee), GFP_KERNEL);
8968 state->frame[state->curframe + 1] = callee;
8970 /* callee cannot access r0, r6 - r9 for reading and has to write
8971 * into its own stack before reading from it.
8972 * callee can read/write into caller's stack
8974 init_func_state(env, callee,
8975 /* remember the callsite, it will be used by bpf_exit */
8976 *insn_idx /* callsite */,
8977 state->curframe + 1 /* frameno within this callchain */,
8978 subprog /* subprog number within this prog */);
8980 /* Transfer references to the callee */
8981 err = copy_reference_state(callee, caller);
8985 err = set_callee_state_cb(env, caller, callee, *insn_idx);
8989 clear_caller_saved_regs(env, caller->regs);
8991 /* only increment it after check_reg_arg() finished */
8994 /* and go analyze first insn of the callee */
8995 *insn_idx = env->subprog_info[subprog].start - 1;
8997 if (env->log.level & BPF_LOG_LEVEL) {
8998 verbose(env, "caller:\n");
8999 print_verifier_state(env, caller, true);
9000 verbose(env, "callee:\n");
9001 print_verifier_state(env, callee, true);
9006 free_func_state(callee);
9007 state->frame[state->curframe + 1] = NULL;
9011 int map_set_for_each_callback_args(struct bpf_verifier_env *env,
9012 struct bpf_func_state *caller,
9013 struct bpf_func_state *callee)
9015 /* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn,
9016 * void *callback_ctx, u64 flags);
9017 * callback_fn(struct bpf_map *map, void *key, void *value,
9018 * void *callback_ctx);
9020 callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
9022 callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
9023 __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
9024 callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr;
9026 callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
9027 __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
9028 callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr;
9030 /* pointer to stack or null */
9031 callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3];
9034 __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
9038 static int set_callee_state(struct bpf_verifier_env *env,
9039 struct bpf_func_state *caller,
9040 struct bpf_func_state *callee, int insn_idx)
9044 /* copy r1 - r5 args that callee can access. The copy includes parent
9045 * pointers, which connects us up to the liveness chain
9047 for (i = BPF_REG_1; i <= BPF_REG_5; i++)
9048 callee->regs[i] = caller->regs[i];
9052 static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
9055 int subprog, target_insn;
9057 target_insn = *insn_idx + insn->imm + 1;
9058 subprog = find_subprog(env, target_insn);
9060 verbose(env, "verifier bug. No program starts at insn %d\n",
9065 return __check_func_call(env, insn, insn_idx, subprog, set_callee_state);
9068 static int set_map_elem_callback_state(struct bpf_verifier_env *env,
9069 struct bpf_func_state *caller,
9070 struct bpf_func_state *callee,
9073 struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx];
9074 struct bpf_map *map;
9077 if (bpf_map_ptr_poisoned(insn_aux)) {
9078 verbose(env, "tail_call abusing map_ptr\n");
9082 map = BPF_MAP_PTR(insn_aux->map_ptr_state);
9083 if (!map->ops->map_set_for_each_callback_args ||
9084 !map->ops->map_for_each_callback) {
9085 verbose(env, "callback function not allowed for map\n");
9089 err = map->ops->map_set_for_each_callback_args(env, caller, callee);
9093 callee->in_callback_fn = true;
9094 callee->callback_ret_range = tnum_range(0, 1);
9098 static int set_loop_callback_state(struct bpf_verifier_env *env,
9099 struct bpf_func_state *caller,
9100 struct bpf_func_state *callee,
9103 /* bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx,
9105 * callback_fn(u32 index, void *callback_ctx);
9107 callee->regs[BPF_REG_1].type = SCALAR_VALUE;
9108 callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
9111 __mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
9112 __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
9113 __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
9115 callee->in_callback_fn = true;
9116 callee->callback_ret_range = tnum_range(0, 1);
9120 static int set_timer_callback_state(struct bpf_verifier_env *env,
9121 struct bpf_func_state *caller,
9122 struct bpf_func_state *callee,
9125 struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
9127 /* bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn);
9128 * callback_fn(struct bpf_map *map, void *key, void *value);
9130 callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
9131 __mark_reg_known_zero(&callee->regs[BPF_REG_1]);
9132 callee->regs[BPF_REG_1].map_ptr = map_ptr;
9134 callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
9135 __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
9136 callee->regs[BPF_REG_2].map_ptr = map_ptr;
9138 callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
9139 __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
9140 callee->regs[BPF_REG_3].map_ptr = map_ptr;
9143 __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
9144 __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
9145 callee->in_async_callback_fn = true;
9146 callee->callback_ret_range = tnum_range(0, 1);
9150 static int set_find_vma_callback_state(struct bpf_verifier_env *env,
9151 struct bpf_func_state *caller,
9152 struct bpf_func_state *callee,
9155 /* bpf_find_vma(struct task_struct *task, u64 addr,
9156 * void *callback_fn, void *callback_ctx, u64 flags)
9157 * (callback_fn)(struct task_struct *task,
9158 * struct vm_area_struct *vma, void *callback_ctx);
9160 callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
9162 callee->regs[BPF_REG_2].type = PTR_TO_BTF_ID;
9163 __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
9164 callee->regs[BPF_REG_2].btf = btf_vmlinux;
9165 callee->regs[BPF_REG_2].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA],
9167 /* pointer to stack or null */
9168 callee->regs[BPF_REG_3] = caller->regs[BPF_REG_4];
9171 __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
9172 __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
9173 callee->in_callback_fn = true;
9174 callee->callback_ret_range = tnum_range(0, 1);
9178 static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env,
9179 struct bpf_func_state *caller,
9180 struct bpf_func_state *callee,
9183 /* bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void
9184 * callback_ctx, u64 flags);
9185 * callback_fn(const struct bpf_dynptr_t* dynptr, void *callback_ctx);
9187 __mark_reg_not_init(env, &callee->regs[BPF_REG_0]);
9188 mark_dynptr_cb_reg(env, &callee->regs[BPF_REG_1], BPF_DYNPTR_TYPE_LOCAL);
9189 callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
9192 __mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
9193 __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
9194 __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
9196 callee->in_callback_fn = true;
9197 callee->callback_ret_range = tnum_range(0, 1);
9201 static int set_rbtree_add_callback_state(struct bpf_verifier_env *env,
9202 struct bpf_func_state *caller,
9203 struct bpf_func_state *callee,
9206 /* void bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
9207 * bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b));
9209 * 'struct bpf_rb_node *node' arg to bpf_rbtree_add_impl is the same PTR_TO_BTF_ID w/ offset
9210 * that 'less' callback args will be receiving. However, 'node' arg was release_reference'd
9211 * by this point, so look at 'root'
9213 struct btf_field *field;
9215 field = reg_find_field_offset(&caller->regs[BPF_REG_1], caller->regs[BPF_REG_1].off,
9217 if (!field || !field->graph_root.value_btf_id)
9220 mark_reg_graph_node(callee->regs, BPF_REG_1, &field->graph_root);
9221 ref_set_non_owning(env, &callee->regs[BPF_REG_1]);
9222 mark_reg_graph_node(callee->regs, BPF_REG_2, &field->graph_root);
9223 ref_set_non_owning(env, &callee->regs[BPF_REG_2]);
9225 __mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
9226 __mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
9227 __mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
9228 callee->in_callback_fn = true;
9229 callee->callback_ret_range = tnum_range(0, 1);
9233 static bool is_rbtree_lock_required_kfunc(u32 btf_id);
9235 /* Are we currently verifying the callback for a rbtree helper that must
9236 * be called with lock held? If so, no need to complain about unreleased
9239 static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env)
9241 struct bpf_verifier_state *state = env->cur_state;
9242 struct bpf_insn *insn = env->prog->insnsi;
9243 struct bpf_func_state *callee;
9246 if (!state->curframe)
9249 callee = state->frame[state->curframe];
9251 if (!callee->in_callback_fn)
9254 kfunc_btf_id = insn[callee->callsite].imm;
9255 return is_rbtree_lock_required_kfunc(kfunc_btf_id);
9258 static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
9260 struct bpf_verifier_state *state = env->cur_state;
9261 struct bpf_func_state *caller, *callee;
9262 struct bpf_reg_state *r0;
9265 callee = state->frame[state->curframe];
9266 r0 = &callee->regs[BPF_REG_0];
9267 if (r0->type == PTR_TO_STACK) {
9268 /* technically it's ok to return caller's stack pointer
9269 * (or caller's caller's pointer) back to the caller,
9270 * since these pointers are valid. Only current stack
9271 * pointer will be invalid as soon as function exits,
9272 * but let's be conservative
9274 verbose(env, "cannot return stack pointer to the caller\n");
9278 caller = state->frame[state->curframe - 1];
9279 if (callee->in_callback_fn) {
9280 /* enforce R0 return value range [0, 1]. */
9281 struct tnum range = callee->callback_ret_range;
9283 if (r0->type != SCALAR_VALUE) {
9284 verbose(env, "R0 not a scalar value\n");
9287 if (!tnum_in(range, r0->var_off)) {
9288 verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
9292 /* return to the caller whatever r0 had in the callee */
9293 caller->regs[BPF_REG_0] = *r0;
9296 /* callback_fn frame should have released its own additions to parent's
9297 * reference state at this point, or check_reference_leak would
9298 * complain, hence it must be the same as the caller. There is no need
9301 if (!callee->in_callback_fn) {
9302 /* Transfer references to the caller */
9303 err = copy_reference_state(caller, callee);
9308 *insn_idx = callee->callsite + 1;
9309 if (env->log.level & BPF_LOG_LEVEL) {
9310 verbose(env, "returning from callee:\n");
9311 print_verifier_state(env, callee, true);
9312 verbose(env, "to caller at %d:\n", *insn_idx);
9313 print_verifier_state(env, caller, true);
9315 /* clear everything in the callee */
9316 free_func_state(callee);
9317 state->frame[state->curframe--] = NULL;
9321 static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
9323 struct bpf_call_arg_meta *meta)
9325 struct bpf_reg_state *ret_reg = ®s[BPF_REG_0];
9327 if (ret_type != RET_INTEGER)
9331 case BPF_FUNC_get_stack:
9332 case BPF_FUNC_get_task_stack:
9333 case BPF_FUNC_probe_read_str:
9334 case BPF_FUNC_probe_read_kernel_str:
9335 case BPF_FUNC_probe_read_user_str:
9336 ret_reg->smax_value = meta->msize_max_value;
9337 ret_reg->s32_max_value = meta->msize_max_value;
9338 ret_reg->smin_value = -MAX_ERRNO;
9339 ret_reg->s32_min_value = -MAX_ERRNO;
9340 reg_bounds_sync(ret_reg);
9342 case BPF_FUNC_get_smp_processor_id:
9343 ret_reg->umax_value = nr_cpu_ids - 1;
9344 ret_reg->u32_max_value = nr_cpu_ids - 1;
9345 ret_reg->smax_value = nr_cpu_ids - 1;
9346 ret_reg->s32_max_value = nr_cpu_ids - 1;
9347 ret_reg->umin_value = 0;
9348 ret_reg->u32_min_value = 0;
9349 ret_reg->smin_value = 0;
9350 ret_reg->s32_min_value = 0;
9351 reg_bounds_sync(ret_reg);
9357 record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
9358 int func_id, int insn_idx)
9360 struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
9361 struct bpf_map *map = meta->map_ptr;
9363 if (func_id != BPF_FUNC_tail_call &&
9364 func_id != BPF_FUNC_map_lookup_elem &&
9365 func_id != BPF_FUNC_map_update_elem &&
9366 func_id != BPF_FUNC_map_delete_elem &&
9367 func_id != BPF_FUNC_map_push_elem &&
9368 func_id != BPF_FUNC_map_pop_elem &&
9369 func_id != BPF_FUNC_map_peek_elem &&
9370 func_id != BPF_FUNC_for_each_map_elem &&
9371 func_id != BPF_FUNC_redirect_map &&
9372 func_id != BPF_FUNC_map_lookup_percpu_elem)
9376 verbose(env, "kernel subsystem misconfigured verifier\n");
9380 /* In case of read-only, some additional restrictions
9381 * need to be applied in order to prevent altering the
9382 * state of the map from program side.
9384 if ((map->map_flags & BPF_F_RDONLY_PROG) &&
9385 (func_id == BPF_FUNC_map_delete_elem ||
9386 func_id == BPF_FUNC_map_update_elem ||
9387 func_id == BPF_FUNC_map_push_elem ||
9388 func_id == BPF_FUNC_map_pop_elem)) {
9389 verbose(env, "write into map forbidden\n");
9393 if (!BPF_MAP_PTR(aux->map_ptr_state))
9394 bpf_map_ptr_store(aux, meta->map_ptr,
9395 !meta->map_ptr->bypass_spec_v1);
9396 else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
9397 bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
9398 !meta->map_ptr->bypass_spec_v1);
9403 record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
9404 int func_id, int insn_idx)
9406 struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
9407 struct bpf_reg_state *regs = cur_regs(env), *reg;
9408 struct bpf_map *map = meta->map_ptr;
9412 if (func_id != BPF_FUNC_tail_call)
9414 if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
9415 verbose(env, "kernel subsystem misconfigured verifier\n");
9419 reg = ®s[BPF_REG_3];
9420 val = reg->var_off.value;
9421 max = map->max_entries;
9423 if (!(register_is_const(reg) && val < max)) {
9424 bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
9428 err = mark_chain_precision(env, BPF_REG_3);
9431 if (bpf_map_key_unseen(aux))
9432 bpf_map_key_store(aux, val);
9433 else if (!bpf_map_key_poisoned(aux) &&
9434 bpf_map_key_immediate(aux) != val)
9435 bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
9439 static int check_reference_leak(struct bpf_verifier_env *env)
9441 struct bpf_func_state *state = cur_func(env);
9442 bool refs_lingering = false;
9445 if (state->frameno && !state->in_callback_fn)
9448 for (i = 0; i < state->acquired_refs; i++) {
9449 if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
9451 verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
9452 state->refs[i].id, state->refs[i].insn_idx);
9453 refs_lingering = true;
9455 return refs_lingering ? -EINVAL : 0;
9458 static int check_bpf_snprintf_call(struct bpf_verifier_env *env,
9459 struct bpf_reg_state *regs)
9461 struct bpf_reg_state *fmt_reg = ®s[BPF_REG_3];
9462 struct bpf_reg_state *data_len_reg = ®s[BPF_REG_5];
9463 struct bpf_map *fmt_map = fmt_reg->map_ptr;
9464 struct bpf_bprintf_data data = {};
9465 int err, fmt_map_off, num_args;
9469 /* data must be an array of u64 */
9470 if (data_len_reg->var_off.value % 8)
9472 num_args = data_len_reg->var_off.value / 8;
9474 /* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const
9475 * and map_direct_value_addr is set.
9477 fmt_map_off = fmt_reg->off + fmt_reg->var_off.value;
9478 err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr,
9481 verbose(env, "verifier bug\n");
9484 fmt = (char *)(long)fmt_addr + fmt_map_off;
9486 /* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we
9487 * can focus on validating the format specifiers.
9489 err = bpf_bprintf_prepare(fmt, UINT_MAX, NULL, num_args, &data);
9491 verbose(env, "Invalid format string\n");
9496 static int check_get_func_ip(struct bpf_verifier_env *env)
9498 enum bpf_prog_type type = resolve_prog_type(env->prog);
9499 int func_id = BPF_FUNC_get_func_ip;
9501 if (type == BPF_PROG_TYPE_TRACING) {
9502 if (!bpf_prog_has_trampoline(env->prog)) {
9503 verbose(env, "func %s#%d supported only for fentry/fexit/fmod_ret programs\n",
9504 func_id_name(func_id), func_id);
9508 } else if (type == BPF_PROG_TYPE_KPROBE) {
9512 verbose(env, "func %s#%d not supported for program type %d\n",
9513 func_id_name(func_id), func_id, type);
9517 static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
9519 return &env->insn_aux_data[env->insn_idx];
9522 static bool loop_flag_is_zero(struct bpf_verifier_env *env)
9524 struct bpf_reg_state *regs = cur_regs(env);
9525 struct bpf_reg_state *reg = ®s[BPF_REG_4];
9526 bool reg_is_null = register_is_null(reg);
9529 mark_chain_precision(env, BPF_REG_4);
9534 static void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
9536 struct bpf_loop_inline_state *state = &cur_aux(env)->loop_inline_state;
9538 if (!state->initialized) {
9539 state->initialized = 1;
9540 state->fit_for_inline = loop_flag_is_zero(env);
9541 state->callback_subprogno = subprogno;
9545 if (!state->fit_for_inline)
9548 state->fit_for_inline = (loop_flag_is_zero(env) &&
9549 state->callback_subprogno == subprogno);
9552 static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
9555 enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
9556 const struct bpf_func_proto *fn = NULL;
9557 enum bpf_return_type ret_type;
9558 enum bpf_type_flag ret_flag;
9559 struct bpf_reg_state *regs;
9560 struct bpf_call_arg_meta meta;
9561 int insn_idx = *insn_idx_p;
9563 int i, err, func_id;
9565 /* find function prototype */
9566 func_id = insn->imm;
9567 if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
9568 verbose(env, "invalid func %s#%d\n", func_id_name(func_id),
9573 if (env->ops->get_func_proto)
9574 fn = env->ops->get_func_proto(func_id, env->prog);
9576 verbose(env, "unknown func %s#%d\n", func_id_name(func_id),
9581 /* eBPF programs must be GPL compatible to use GPL-ed functions */
9582 if (!env->prog->gpl_compatible && fn->gpl_only) {
9583 verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n");
9587 if (fn->allowed && !fn->allowed(env->prog)) {
9588 verbose(env, "helper call is not allowed in probe\n");
9592 if (!env->prog->aux->sleepable && fn->might_sleep) {
9593 verbose(env, "helper call might sleep in a non-sleepable prog\n");
9597 /* With LD_ABS/IND some JITs save/restore skb from r1. */
9598 changes_data = bpf_helper_changes_pkt_data(fn->func);
9599 if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
9600 verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
9601 func_id_name(func_id), func_id);
9605 memset(&meta, 0, sizeof(meta));
9606 meta.pkt_access = fn->pkt_access;
9608 err = check_func_proto(fn, func_id);
9610 verbose(env, "kernel subsystem misconfigured func %s#%d\n",
9611 func_id_name(func_id), func_id);
9615 if (env->cur_state->active_rcu_lock) {
9616 if (fn->might_sleep) {
9617 verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n",
9618 func_id_name(func_id), func_id);
9622 if (env->prog->aux->sleepable && is_storage_get_function(func_id))
9623 env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
9626 meta.func_id = func_id;
9628 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
9629 err = check_func_arg(env, i, &meta, fn, insn_idx);
9634 err = record_func_map(env, &meta, func_id, insn_idx);
9638 err = record_func_key(env, &meta, func_id, insn_idx);
9642 /* Mark slots with STACK_MISC in case of raw mode, stack offset
9643 * is inferred from register state.
9645 for (i = 0; i < meta.access_size; i++) {
9646 err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
9647 BPF_WRITE, -1, false, false);
9652 regs = cur_regs(env);
9654 if (meta.release_regno) {
9656 /* This can only be set for PTR_TO_STACK, as CONST_PTR_TO_DYNPTR cannot
9657 * be released by any dynptr helper. Hence, unmark_stack_slots_dynptr
9658 * is safe to do directly.
9660 if (arg_type_is_dynptr(fn->arg_type[meta.release_regno - BPF_REG_1])) {
9661 if (regs[meta.release_regno].type == CONST_PTR_TO_DYNPTR) {
9662 verbose(env, "verifier internal error: CONST_PTR_TO_DYNPTR cannot be released\n");
9665 err = unmark_stack_slots_dynptr(env, ®s[meta.release_regno]);
9666 } else if (meta.ref_obj_id) {
9667 err = release_reference(env, meta.ref_obj_id);
9668 } else if (register_is_null(®s[meta.release_regno])) {
9669 /* meta.ref_obj_id can only be 0 if register that is meant to be
9670 * released is NULL, which must be > R0.
9675 verbose(env, "func %s#%d reference has not been acquired before\n",
9676 func_id_name(func_id), func_id);
9682 case BPF_FUNC_tail_call:
9683 err = check_reference_leak(env);
9685 verbose(env, "tail_call would lead to reference leak\n");
9689 case BPF_FUNC_get_local_storage:
9690 /* check that flags argument in get_local_storage(map, flags) is 0,
9691 * this is required because get_local_storage() can't return an error.
9693 if (!register_is_null(®s[BPF_REG_2])) {
9694 verbose(env, "get_local_storage() doesn't support non-zero flags\n");
9698 case BPF_FUNC_for_each_map_elem:
9699 err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9700 set_map_elem_callback_state);
9702 case BPF_FUNC_timer_set_callback:
9703 err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9704 set_timer_callback_state);
9706 case BPF_FUNC_find_vma:
9707 err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9708 set_find_vma_callback_state);
9710 case BPF_FUNC_snprintf:
9711 err = check_bpf_snprintf_call(env, regs);
9714 update_loop_inline_state(env, meta.subprogno);
9715 err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9716 set_loop_callback_state);
9718 case BPF_FUNC_dynptr_from_mem:
9719 if (regs[BPF_REG_1].type != PTR_TO_MAP_VALUE) {
9720 verbose(env, "Unsupported reg type %s for bpf_dynptr_from_mem data\n",
9721 reg_type_str(env, regs[BPF_REG_1].type));
9725 case BPF_FUNC_set_retval:
9726 if (prog_type == BPF_PROG_TYPE_LSM &&
9727 env->prog->expected_attach_type == BPF_LSM_CGROUP) {
9728 if (!env->prog->aux->attach_func_proto->type) {
9729 /* Make sure programs that attach to void
9730 * hooks don't try to modify return value.
9732 verbose(env, "BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
9737 case BPF_FUNC_dynptr_data:
9739 struct bpf_reg_state *reg;
9742 reg = get_dynptr_arg_reg(env, fn, regs);
9747 if (meta.dynptr_id) {
9748 verbose(env, "verifier internal error: meta.dynptr_id already set\n");
9751 if (meta.ref_obj_id) {
9752 verbose(env, "verifier internal error: meta.ref_obj_id already set\n");
9756 id = dynptr_id(env, reg);
9758 verbose(env, "verifier internal error: failed to obtain dynptr id\n");
9762 ref_obj_id = dynptr_ref_obj_id(env, reg);
9763 if (ref_obj_id < 0) {
9764 verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n");
9768 meta.dynptr_id = id;
9769 meta.ref_obj_id = ref_obj_id;
9773 case BPF_FUNC_dynptr_write:
9775 enum bpf_dynptr_type dynptr_type;
9776 struct bpf_reg_state *reg;
9778 reg = get_dynptr_arg_reg(env, fn, regs);
9782 dynptr_type = dynptr_get_type(env, reg);
9783 if (dynptr_type == BPF_DYNPTR_TYPE_INVALID)
9786 if (dynptr_type == BPF_DYNPTR_TYPE_SKB)
9787 /* this will trigger clear_all_pkt_pointers(), which will
9788 * invalidate all dynptr slices associated with the skb
9790 changes_data = true;
9794 case BPF_FUNC_user_ringbuf_drain:
9795 err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9796 set_user_ringbuf_callback_state);
9803 /* reset caller saved regs */
9804 for (i = 0; i < CALLER_SAVED_REGS; i++) {
9805 mark_reg_not_init(env, regs, caller_saved[i]);
9806 check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
9809 /* helper call returns 64-bit value. */
9810 regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
9812 /* update return register (already marked as written above) */
9813 ret_type = fn->ret_type;
9814 ret_flag = type_flag(ret_type);
9816 switch (base_type(ret_type)) {
9818 /* sets type to SCALAR_VALUE */
9819 mark_reg_unknown(env, regs, BPF_REG_0);
9822 regs[BPF_REG_0].type = NOT_INIT;
9824 case RET_PTR_TO_MAP_VALUE:
9825 /* There is no offset yet applied, variable or fixed */
9826 mark_reg_known_zero(env, regs, BPF_REG_0);
9827 /* remember map_ptr, so that check_map_access()
9828 * can check 'value_size' boundary of memory access
9829 * to map element returned from bpf_map_lookup_elem()
9831 if (meta.map_ptr == NULL) {
9833 "kernel subsystem misconfigured verifier\n");
9836 regs[BPF_REG_0].map_ptr = meta.map_ptr;
9837 regs[BPF_REG_0].map_uid = meta.map_uid;
9838 regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag;
9839 if (!type_may_be_null(ret_type) &&
9840 btf_record_has_field(meta.map_ptr->record, BPF_SPIN_LOCK)) {
9841 regs[BPF_REG_0].id = ++env->id_gen;
9844 case RET_PTR_TO_SOCKET:
9845 mark_reg_known_zero(env, regs, BPF_REG_0);
9846 regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
9848 case RET_PTR_TO_SOCK_COMMON:
9849 mark_reg_known_zero(env, regs, BPF_REG_0);
9850 regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
9852 case RET_PTR_TO_TCP_SOCK:
9853 mark_reg_known_zero(env, regs, BPF_REG_0);
9854 regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
9856 case RET_PTR_TO_MEM:
9857 mark_reg_known_zero(env, regs, BPF_REG_0);
9858 regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
9859 regs[BPF_REG_0].mem_size = meta.mem_size;
9861 case RET_PTR_TO_MEM_OR_BTF_ID:
9863 const struct btf_type *t;
9865 mark_reg_known_zero(env, regs, BPF_REG_0);
9866 t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
9867 if (!btf_type_is_struct(t)) {
9869 const struct btf_type *ret;
9872 /* resolve the type size of ksym. */
9873 ret = btf_resolve_size(meta.ret_btf, t, &tsize);
9875 tname = btf_name_by_offset(meta.ret_btf, t->name_off);
9876 verbose(env, "unable to resolve the size of type '%s': %ld\n",
9877 tname, PTR_ERR(ret));
9880 regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
9881 regs[BPF_REG_0].mem_size = tsize;
9883 /* MEM_RDONLY may be carried from ret_flag, but it
9884 * doesn't apply on PTR_TO_BTF_ID. Fold it, otherwise
9885 * it will confuse the check of PTR_TO_BTF_ID in
9886 * check_mem_access().
9888 ret_flag &= ~MEM_RDONLY;
9890 regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
9891 regs[BPF_REG_0].btf = meta.ret_btf;
9892 regs[BPF_REG_0].btf_id = meta.ret_btf_id;
9896 case RET_PTR_TO_BTF_ID:
9898 struct btf *ret_btf;
9901 mark_reg_known_zero(env, regs, BPF_REG_0);
9902 regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
9903 if (func_id == BPF_FUNC_kptr_xchg) {
9904 ret_btf = meta.kptr_field->kptr.btf;
9905 ret_btf_id = meta.kptr_field->kptr.btf_id;
9906 if (!btf_is_kernel(ret_btf))
9907 regs[BPF_REG_0].type |= MEM_ALLOC;
9909 if (fn->ret_btf_id == BPF_PTR_POISON) {
9910 verbose(env, "verifier internal error:");
9911 verbose(env, "func %s has non-overwritten BPF_PTR_POISON return type\n",
9912 func_id_name(func_id));
9915 ret_btf = btf_vmlinux;
9916 ret_btf_id = *fn->ret_btf_id;
9918 if (ret_btf_id == 0) {
9919 verbose(env, "invalid return type %u of func %s#%d\n",
9920 base_type(ret_type), func_id_name(func_id),
9924 regs[BPF_REG_0].btf = ret_btf;
9925 regs[BPF_REG_0].btf_id = ret_btf_id;
9929 verbose(env, "unknown return type %u of func %s#%d\n",
9930 base_type(ret_type), func_id_name(func_id), func_id);
9934 if (type_may_be_null(regs[BPF_REG_0].type))
9935 regs[BPF_REG_0].id = ++env->id_gen;
9937 if (helper_multiple_ref_obj_use(func_id, meta.map_ptr)) {
9938 verbose(env, "verifier internal error: func %s#%d sets ref_obj_id more than once\n",
9939 func_id_name(func_id), func_id);
9943 if (is_dynptr_ref_function(func_id))
9944 regs[BPF_REG_0].dynptr_id = meta.dynptr_id;
9946 if (is_ptr_cast_function(func_id) || is_dynptr_ref_function(func_id)) {
9947 /* For release_reference() */
9948 regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
9949 } else if (is_acquire_function(func_id, meta.map_ptr)) {
9950 int id = acquire_reference_state(env, insn_idx);
9954 /* For mark_ptr_or_null_reg() */
9955 regs[BPF_REG_0].id = id;
9956 /* For release_reference() */
9957 regs[BPF_REG_0].ref_obj_id = id;
9960 do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
9962 err = check_map_func_compatibility(env, meta.map_ptr, func_id);
9966 if ((func_id == BPF_FUNC_get_stack ||
9967 func_id == BPF_FUNC_get_task_stack) &&
9968 !env->prog->has_callchain_buf) {
9969 const char *err_str;
9971 #ifdef CONFIG_PERF_EVENTS
9972 err = get_callchain_buffers(sysctl_perf_event_max_stack);
9973 err_str = "cannot get callchain buffer for func %s#%d\n";
9976 err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
9979 verbose(env, err_str, func_id_name(func_id), func_id);
9983 env->prog->has_callchain_buf = true;
9986 if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack)
9987 env->prog->call_get_stack = true;
9989 if (func_id == BPF_FUNC_get_func_ip) {
9990 if (check_get_func_ip(env))
9992 env->prog->call_get_func_ip = true;
9996 clear_all_pkt_pointers(env);
10000 /* mark_btf_func_reg_size() is used when the reg size is determined by
10001 * the BTF func_proto's return value size and argument.
10003 static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno,
10006 struct bpf_reg_state *reg = &cur_regs(env)[regno];
10008 if (regno == BPF_REG_0) {
10009 /* Function return value */
10010 reg->live |= REG_LIVE_WRITTEN;
10011 reg->subreg_def = reg_size == sizeof(u64) ?
10012 DEF_NOT_SUBREG : env->insn_idx + 1;
10014 /* Function argument */
10015 if (reg_size == sizeof(u64)) {
10016 mark_insn_zext(env, reg);
10017 mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
10019 mark_reg_read(env, reg, reg->parent, REG_LIVE_READ32);
10024 static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
10026 return meta->kfunc_flags & KF_ACQUIRE;
10029 static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta)
10031 return meta->kfunc_flags & KF_RELEASE;
10034 static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta)
10036 return (meta->kfunc_flags & KF_TRUSTED_ARGS) || is_kfunc_release(meta);
10039 static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta)
10041 return meta->kfunc_flags & KF_SLEEPABLE;
10044 static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta)
10046 return meta->kfunc_flags & KF_DESTRUCTIVE;
10049 static bool is_kfunc_rcu(struct bpf_kfunc_call_arg_meta *meta)
10051 return meta->kfunc_flags & KF_RCU;
10054 static bool __kfunc_param_match_suffix(const struct btf *btf,
10055 const struct btf_param *arg,
10056 const char *suffix)
10058 int suffix_len = strlen(suffix), len;
10059 const char *param_name;
10061 /* In the future, this can be ported to use BTF tagging */
10062 param_name = btf_name_by_offset(btf, arg->name_off);
10063 if (str_is_empty(param_name))
10065 len = strlen(param_name);
10066 if (len < suffix_len)
10068 param_name += len - suffix_len;
10069 return !strncmp(param_name, suffix, suffix_len);
10072 static bool is_kfunc_arg_mem_size(const struct btf *btf,
10073 const struct btf_param *arg,
10074 const struct bpf_reg_state *reg)
10076 const struct btf_type *t;
10078 t = btf_type_skip_modifiers(btf, arg->type, NULL);
10079 if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
10082 return __kfunc_param_match_suffix(btf, arg, "__sz");
10085 static bool is_kfunc_arg_const_mem_size(const struct btf *btf,
10086 const struct btf_param *arg,
10087 const struct bpf_reg_state *reg)
10089 const struct btf_type *t;
10091 t = btf_type_skip_modifiers(btf, arg->type, NULL);
10092 if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
10095 return __kfunc_param_match_suffix(btf, arg, "__szk");
10098 static bool is_kfunc_arg_optional(const struct btf *btf, const struct btf_param *arg)
10100 return __kfunc_param_match_suffix(btf, arg, "__opt");
10103 static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg)
10105 return __kfunc_param_match_suffix(btf, arg, "__k");
10108 static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *arg)
10110 return __kfunc_param_match_suffix(btf, arg, "__ign");
10113 static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param *arg)
10115 return __kfunc_param_match_suffix(btf, arg, "__alloc");
10118 static bool is_kfunc_arg_uninit(const struct btf *btf, const struct btf_param *arg)
10120 return __kfunc_param_match_suffix(btf, arg, "__uninit");
10123 static bool is_kfunc_arg_refcounted_kptr(const struct btf *btf, const struct btf_param *arg)
10125 return __kfunc_param_match_suffix(btf, arg, "__refcounted_kptr");
10128 static bool is_kfunc_arg_scalar_with_name(const struct btf *btf,
10129 const struct btf_param *arg,
10132 int len, target_len = strlen(name);
10133 const char *param_name;
10135 param_name = btf_name_by_offset(btf, arg->name_off);
10136 if (str_is_empty(param_name))
10138 len = strlen(param_name);
10139 if (len != target_len)
10141 if (strcmp(param_name, name))
10149 KF_ARG_LIST_HEAD_ID,
10150 KF_ARG_LIST_NODE_ID,
10155 BTF_ID_LIST(kf_arg_btf_ids)
10156 BTF_ID(struct, bpf_dynptr_kern)
10157 BTF_ID(struct, bpf_list_head)
10158 BTF_ID(struct, bpf_list_node)
10159 BTF_ID(struct, bpf_rb_root)
10160 BTF_ID(struct, bpf_rb_node)
10162 static bool __is_kfunc_ptr_arg_type(const struct btf *btf,
10163 const struct btf_param *arg, int type)
10165 const struct btf_type *t;
10168 t = btf_type_skip_modifiers(btf, arg->type, NULL);
10171 if (!btf_type_is_ptr(t))
10173 t = btf_type_skip_modifiers(btf, t->type, &res_id);
10176 return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[type]);
10179 static bool is_kfunc_arg_dynptr(const struct btf *btf, const struct btf_param *arg)
10181 return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_DYNPTR_ID);
10184 static bool is_kfunc_arg_list_head(const struct btf *btf, const struct btf_param *arg)
10186 return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_HEAD_ID);
10189 static bool is_kfunc_arg_list_node(const struct btf *btf, const struct btf_param *arg)
10191 return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_NODE_ID);
10194 static bool is_kfunc_arg_rbtree_root(const struct btf *btf, const struct btf_param *arg)
10196 return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_ROOT_ID);
10199 static bool is_kfunc_arg_rbtree_node(const struct btf *btf, const struct btf_param *arg)
10201 return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_NODE_ID);
10204 static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf,
10205 const struct btf_param *arg)
10207 const struct btf_type *t;
10209 t = btf_type_resolve_func_ptr(btf, arg->type, NULL);
10216 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
10217 static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
10218 const struct btf *btf,
10219 const struct btf_type *t, int rec)
10221 const struct btf_type *member_type;
10222 const struct btf_member *member;
10225 if (!btf_type_is_struct(t))
10228 for_each_member(i, t, member) {
10229 const struct btf_array *array;
10231 member_type = btf_type_skip_modifiers(btf, member->type, NULL);
10232 if (btf_type_is_struct(member_type)) {
10234 verbose(env, "max struct nesting depth exceeded\n");
10237 if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1))
10241 if (btf_type_is_array(member_type)) {
10242 array = btf_array(member_type);
10243 if (!array->nelems)
10245 member_type = btf_type_skip_modifiers(btf, array->type, NULL);
10246 if (!btf_type_is_scalar(member_type))
10250 if (!btf_type_is_scalar(member_type))
10256 enum kfunc_ptr_arg_type {
10258 KF_ARG_PTR_TO_ALLOC_BTF_ID, /* Allocated object */
10259 KF_ARG_PTR_TO_REFCOUNTED_KPTR, /* Refcounted local kptr */
10260 KF_ARG_PTR_TO_DYNPTR,
10261 KF_ARG_PTR_TO_ITER,
10262 KF_ARG_PTR_TO_LIST_HEAD,
10263 KF_ARG_PTR_TO_LIST_NODE,
10264 KF_ARG_PTR_TO_BTF_ID, /* Also covers reg2btf_ids conversions */
10266 KF_ARG_PTR_TO_MEM_SIZE, /* Size derived from next argument, skip it */
10267 KF_ARG_PTR_TO_CALLBACK,
10268 KF_ARG_PTR_TO_RB_ROOT,
10269 KF_ARG_PTR_TO_RB_NODE,
10272 enum special_kfunc_type {
10273 KF_bpf_obj_new_impl,
10274 KF_bpf_obj_drop_impl,
10275 KF_bpf_refcount_acquire_impl,
10276 KF_bpf_list_push_front_impl,
10277 KF_bpf_list_push_back_impl,
10278 KF_bpf_list_pop_front,
10279 KF_bpf_list_pop_back,
10280 KF_bpf_cast_to_kern_ctx,
10281 KF_bpf_rdonly_cast,
10282 KF_bpf_rcu_read_lock,
10283 KF_bpf_rcu_read_unlock,
10284 KF_bpf_rbtree_remove,
10285 KF_bpf_rbtree_add_impl,
10286 KF_bpf_rbtree_first,
10287 KF_bpf_dynptr_from_skb,
10288 KF_bpf_dynptr_from_xdp,
10289 KF_bpf_dynptr_slice,
10290 KF_bpf_dynptr_slice_rdwr,
10291 KF_bpf_dynptr_clone,
10294 BTF_SET_START(special_kfunc_set)
10295 BTF_ID(func, bpf_obj_new_impl)
10296 BTF_ID(func, bpf_obj_drop_impl)
10297 BTF_ID(func, bpf_refcount_acquire_impl)
10298 BTF_ID(func, bpf_list_push_front_impl)
10299 BTF_ID(func, bpf_list_push_back_impl)
10300 BTF_ID(func, bpf_list_pop_front)
10301 BTF_ID(func, bpf_list_pop_back)
10302 BTF_ID(func, bpf_cast_to_kern_ctx)
10303 BTF_ID(func, bpf_rdonly_cast)
10304 BTF_ID(func, bpf_rbtree_remove)
10305 BTF_ID(func, bpf_rbtree_add_impl)
10306 BTF_ID(func, bpf_rbtree_first)
10307 BTF_ID(func, bpf_dynptr_from_skb)
10308 BTF_ID(func, bpf_dynptr_from_xdp)
10309 BTF_ID(func, bpf_dynptr_slice)
10310 BTF_ID(func, bpf_dynptr_slice_rdwr)
10311 BTF_ID(func, bpf_dynptr_clone)
10312 BTF_SET_END(special_kfunc_set)
10314 BTF_ID_LIST(special_kfunc_list)
10315 BTF_ID(func, bpf_obj_new_impl)
10316 BTF_ID(func, bpf_obj_drop_impl)
10317 BTF_ID(func, bpf_refcount_acquire_impl)
10318 BTF_ID(func, bpf_list_push_front_impl)
10319 BTF_ID(func, bpf_list_push_back_impl)
10320 BTF_ID(func, bpf_list_pop_front)
10321 BTF_ID(func, bpf_list_pop_back)
10322 BTF_ID(func, bpf_cast_to_kern_ctx)
10323 BTF_ID(func, bpf_rdonly_cast)
10324 BTF_ID(func, bpf_rcu_read_lock)
10325 BTF_ID(func, bpf_rcu_read_unlock)
10326 BTF_ID(func, bpf_rbtree_remove)
10327 BTF_ID(func, bpf_rbtree_add_impl)
10328 BTF_ID(func, bpf_rbtree_first)
10329 BTF_ID(func, bpf_dynptr_from_skb)
10330 BTF_ID(func, bpf_dynptr_from_xdp)
10331 BTF_ID(func, bpf_dynptr_slice)
10332 BTF_ID(func, bpf_dynptr_slice_rdwr)
10333 BTF_ID(func, bpf_dynptr_clone)
10335 static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
10337 if (meta->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
10338 meta->arg_owning_ref) {
10342 return meta->kfunc_flags & KF_RET_NULL;
10345 static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta)
10347 return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_lock];
10350 static bool is_kfunc_bpf_rcu_read_unlock(struct bpf_kfunc_call_arg_meta *meta)
10352 return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_unlock];
10355 static enum kfunc_ptr_arg_type
10356 get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
10357 struct bpf_kfunc_call_arg_meta *meta,
10358 const struct btf_type *t, const struct btf_type *ref_t,
10359 const char *ref_tname, const struct btf_param *args,
10360 int argno, int nargs)
10362 u32 regno = argno + 1;
10363 struct bpf_reg_state *regs = cur_regs(env);
10364 struct bpf_reg_state *reg = ®s[regno];
10365 bool arg_mem_size = false;
10367 if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx])
10368 return KF_ARG_PTR_TO_CTX;
10370 /* In this function, we verify the kfunc's BTF as per the argument type,
10371 * leaving the rest of the verification with respect to the register
10372 * type to our caller. When a set of conditions hold in the BTF type of
10373 * arguments, we resolve it to a known kfunc_ptr_arg_type.
10375 if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
10376 return KF_ARG_PTR_TO_CTX;
10378 if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno]))
10379 return KF_ARG_PTR_TO_ALLOC_BTF_ID;
10381 if (is_kfunc_arg_refcounted_kptr(meta->btf, &args[argno]))
10382 return KF_ARG_PTR_TO_REFCOUNTED_KPTR;
10384 if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
10385 return KF_ARG_PTR_TO_DYNPTR;
10387 if (is_kfunc_arg_iter(meta, argno))
10388 return KF_ARG_PTR_TO_ITER;
10390 if (is_kfunc_arg_list_head(meta->btf, &args[argno]))
10391 return KF_ARG_PTR_TO_LIST_HEAD;
10393 if (is_kfunc_arg_list_node(meta->btf, &args[argno]))
10394 return KF_ARG_PTR_TO_LIST_NODE;
10396 if (is_kfunc_arg_rbtree_root(meta->btf, &args[argno]))
10397 return KF_ARG_PTR_TO_RB_ROOT;
10399 if (is_kfunc_arg_rbtree_node(meta->btf, &args[argno]))
10400 return KF_ARG_PTR_TO_RB_NODE;
10402 if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) {
10403 if (!btf_type_is_struct(ref_t)) {
10404 verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n",
10405 meta->func_name, argno, btf_type_str(ref_t), ref_tname);
10408 return KF_ARG_PTR_TO_BTF_ID;
10411 if (is_kfunc_arg_callback(env, meta->btf, &args[argno]))
10412 return KF_ARG_PTR_TO_CALLBACK;
10415 if (argno + 1 < nargs &&
10416 (is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1]) ||
10417 is_kfunc_arg_const_mem_size(meta->btf, &args[argno + 1], ®s[regno + 1])))
10418 arg_mem_size = true;
10420 /* This is the catch all argument type of register types supported by
10421 * check_helper_mem_access. However, we only allow when argument type is
10422 * pointer to scalar, or struct composed (recursively) of scalars. When
10423 * arg_mem_size is true, the pointer can be void *.
10425 if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) &&
10426 (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
10427 verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
10428 argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
10431 return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM;
10434 static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
10435 struct bpf_reg_state *reg,
10436 const struct btf_type *ref_t,
10437 const char *ref_tname, u32 ref_id,
10438 struct bpf_kfunc_call_arg_meta *meta,
10441 const struct btf_type *reg_ref_t;
10442 bool strict_type_match = false;
10443 const struct btf *reg_btf;
10444 const char *reg_ref_tname;
10447 if (base_type(reg->type) == PTR_TO_BTF_ID) {
10448 reg_btf = reg->btf;
10449 reg_ref_id = reg->btf_id;
10451 reg_btf = btf_vmlinux;
10452 reg_ref_id = *reg2btf_ids[base_type(reg->type)];
10455 /* Enforce strict type matching for calls to kfuncs that are acquiring
10456 * or releasing a reference, or are no-cast aliases. We do _not_
10457 * enforce strict matching for plain KF_TRUSTED_ARGS kfuncs by default,
10458 * as we want to enable BPF programs to pass types that are bitwise
10459 * equivalent without forcing them to explicitly cast with something
10460 * like bpf_cast_to_kern_ctx().
10462 * For example, say we had a type like the following:
10464 * struct bpf_cpumask {
10465 * cpumask_t cpumask;
10466 * refcount_t usage;
10469 * Note that as specified in <linux/cpumask.h>, cpumask_t is typedef'ed
10470 * to a struct cpumask, so it would be safe to pass a struct
10471 * bpf_cpumask * to a kfunc expecting a struct cpumask *.
10473 * The philosophy here is similar to how we allow scalars of different
10474 * types to be passed to kfuncs as long as the size is the same. The
10475 * only difference here is that we're simply allowing
10476 * btf_struct_ids_match() to walk the struct at the 0th offset, and
10479 if (is_kfunc_acquire(meta) ||
10480 (is_kfunc_release(meta) && reg->ref_obj_id) ||
10481 btf_type_ids_nocast_alias(&env->log, reg_btf, reg_ref_id, meta->btf, ref_id))
10482 strict_type_match = true;
10484 WARN_ON_ONCE(is_kfunc_trusted_args(meta) && reg->off);
10486 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, ®_ref_id);
10487 reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off);
10488 if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) {
10489 verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
10490 meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1,
10491 btf_type_str(reg_ref_t), reg_ref_tname);
10497 static int ref_set_non_owning(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
10499 struct bpf_verifier_state *state = env->cur_state;
10500 struct btf_record *rec = reg_btf_record(reg);
10502 if (!state->active_lock.ptr) {
10503 verbose(env, "verifier internal error: ref_set_non_owning w/o active lock\n");
10507 if (type_flag(reg->type) & NON_OWN_REF) {
10508 verbose(env, "verifier internal error: NON_OWN_REF already set\n");
10512 reg->type |= NON_OWN_REF;
10513 if (rec->refcount_off >= 0)
10514 reg->type |= MEM_RCU;
10519 static int ref_convert_owning_non_owning(struct bpf_verifier_env *env, u32 ref_obj_id)
10521 struct bpf_func_state *state, *unused;
10522 struct bpf_reg_state *reg;
10525 state = cur_func(env);
10528 verbose(env, "verifier internal error: ref_obj_id is zero for "
10529 "owning -> non-owning conversion\n");
10533 for (i = 0; i < state->acquired_refs; i++) {
10534 if (state->refs[i].id != ref_obj_id)
10537 /* Clear ref_obj_id here so release_reference doesn't clobber
10540 bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
10541 if (reg->ref_obj_id == ref_obj_id) {
10542 reg->ref_obj_id = 0;
10543 ref_set_non_owning(env, reg);
10549 verbose(env, "verifier internal error: ref state missing for ref_obj_id\n");
10553 /* Implementation details:
10555 * Each register points to some region of memory, which we define as an
10556 * allocation. Each allocation may embed a bpf_spin_lock which protects any
10557 * special BPF objects (bpf_list_head, bpf_rb_root, etc.) part of the same
10558 * allocation. The lock and the data it protects are colocated in the same
10561 * Hence, everytime a register holds a pointer value pointing to such
10562 * allocation, the verifier preserves a unique reg->id for it.
10564 * The verifier remembers the lock 'ptr' and the lock 'id' whenever
10565 * bpf_spin_lock is called.
10567 * To enable this, lock state in the verifier captures two values:
10568 * active_lock.ptr = Register's type specific pointer
10569 * active_lock.id = A unique ID for each register pointer value
10571 * Currently, PTR_TO_MAP_VALUE and PTR_TO_BTF_ID | MEM_ALLOC are the two
10572 * supported register types.
10574 * The active_lock.ptr in case of map values is the reg->map_ptr, and in case of
10575 * allocated objects is the reg->btf pointer.
10577 * The active_lock.id is non-unique for maps supporting direct_value_addr, as we
10578 * can establish the provenance of the map value statically for each distinct
10579 * lookup into such maps. They always contain a single map value hence unique
10580 * IDs for each pseudo load pessimizes the algorithm and rejects valid programs.
10582 * So, in case of global variables, they use array maps with max_entries = 1,
10583 * hence their active_lock.ptr becomes map_ptr and id = 0 (since they all point
10584 * into the same map value as max_entries is 1, as described above).
10586 * In case of inner map lookups, the inner map pointer has same map_ptr as the
10587 * outer map pointer (in verifier context), but each lookup into an inner map
10588 * assigns a fresh reg->id to the lookup, so while lookups into distinct inner
10589 * maps from the same outer map share the same map_ptr as active_lock.ptr, they
10590 * will get different reg->id assigned to each lookup, hence different
10593 * In case of allocated objects, active_lock.ptr is the reg->btf, and the
10594 * reg->id is a unique ID preserved after the NULL pointer check on the pointer
10595 * returned from bpf_obj_new. Each allocation receives a new reg->id.
10597 static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
10602 switch ((int)reg->type) {
10603 case PTR_TO_MAP_VALUE:
10604 ptr = reg->map_ptr;
10606 case PTR_TO_BTF_ID | MEM_ALLOC:
10610 verbose(env, "verifier internal error: unknown reg type for lock check\n");
10615 if (!env->cur_state->active_lock.ptr)
10617 if (env->cur_state->active_lock.ptr != ptr ||
10618 env->cur_state->active_lock.id != id) {
10619 verbose(env, "held lock and object are not in the same allocation\n");
10625 static bool is_bpf_list_api_kfunc(u32 btf_id)
10627 return btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
10628 btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
10629 btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
10630 btf_id == special_kfunc_list[KF_bpf_list_pop_back];
10633 static bool is_bpf_rbtree_api_kfunc(u32 btf_id)
10635 return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] ||
10636 btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
10637 btf_id == special_kfunc_list[KF_bpf_rbtree_first];
10640 static bool is_bpf_graph_api_kfunc(u32 btf_id)
10642 return is_bpf_list_api_kfunc(btf_id) || is_bpf_rbtree_api_kfunc(btf_id) ||
10643 btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
10646 static bool is_callback_calling_kfunc(u32 btf_id)
10648 return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
10651 static bool is_rbtree_lock_required_kfunc(u32 btf_id)
10653 return is_bpf_rbtree_api_kfunc(btf_id);
10656 static bool check_kfunc_is_graph_root_api(struct bpf_verifier_env *env,
10657 enum btf_field_type head_field_type,
10662 switch (head_field_type) {
10663 case BPF_LIST_HEAD:
10664 ret = is_bpf_list_api_kfunc(kfunc_btf_id);
10667 ret = is_bpf_rbtree_api_kfunc(kfunc_btf_id);
10670 verbose(env, "verifier internal error: unexpected graph root argument type %s\n",
10671 btf_field_type_name(head_field_type));
10676 verbose(env, "verifier internal error: %s head arg for unknown kfunc\n",
10677 btf_field_type_name(head_field_type));
10681 static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
10682 enum btf_field_type node_field_type,
10687 switch (node_field_type) {
10688 case BPF_LIST_NODE:
10689 ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
10690 kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
10693 ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
10694 kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl]);
10697 verbose(env, "verifier internal error: unexpected graph node argument type %s\n",
10698 btf_field_type_name(node_field_type));
10703 verbose(env, "verifier internal error: %s node arg for unknown kfunc\n",
10704 btf_field_type_name(node_field_type));
10709 __process_kf_arg_ptr_to_graph_root(struct bpf_verifier_env *env,
10710 struct bpf_reg_state *reg, u32 regno,
10711 struct bpf_kfunc_call_arg_meta *meta,
10712 enum btf_field_type head_field_type,
10713 struct btf_field **head_field)
10715 const char *head_type_name;
10716 struct btf_field *field;
10717 struct btf_record *rec;
10720 if (meta->btf != btf_vmlinux) {
10721 verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
10725 if (!check_kfunc_is_graph_root_api(env, head_field_type, meta->func_id))
10728 head_type_name = btf_field_type_name(head_field_type);
10729 if (!tnum_is_const(reg->var_off)) {
10731 "R%d doesn't have constant offset. %s has to be at the constant offset\n",
10732 regno, head_type_name);
10736 rec = reg_btf_record(reg);
10737 head_off = reg->off + reg->var_off.value;
10738 field = btf_record_find(rec, head_off, head_field_type);
10740 verbose(env, "%s not found at offset=%u\n", head_type_name, head_off);
10744 /* All functions require bpf_list_head to be protected using a bpf_spin_lock */
10745 if (check_reg_allocation_locked(env, reg)) {
10746 verbose(env, "bpf_spin_lock at off=%d must be held for %s\n",
10747 rec->spin_lock_off, head_type_name);
10752 verbose(env, "verifier internal error: repeating %s arg\n", head_type_name);
10755 *head_field = field;
10759 static int process_kf_arg_ptr_to_list_head(struct bpf_verifier_env *env,
10760 struct bpf_reg_state *reg, u32 regno,
10761 struct bpf_kfunc_call_arg_meta *meta)
10763 return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_LIST_HEAD,
10764 &meta->arg_list_head.field);
10767 static int process_kf_arg_ptr_to_rbtree_root(struct bpf_verifier_env *env,
10768 struct bpf_reg_state *reg, u32 regno,
10769 struct bpf_kfunc_call_arg_meta *meta)
10771 return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_RB_ROOT,
10772 &meta->arg_rbtree_root.field);
10776 __process_kf_arg_ptr_to_graph_node(struct bpf_verifier_env *env,
10777 struct bpf_reg_state *reg, u32 regno,
10778 struct bpf_kfunc_call_arg_meta *meta,
10779 enum btf_field_type head_field_type,
10780 enum btf_field_type node_field_type,
10781 struct btf_field **node_field)
10783 const char *node_type_name;
10784 const struct btf_type *et, *t;
10785 struct btf_field *field;
10788 if (meta->btf != btf_vmlinux) {
10789 verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
10793 if (!check_kfunc_is_graph_node_api(env, node_field_type, meta->func_id))
10796 node_type_name = btf_field_type_name(node_field_type);
10797 if (!tnum_is_const(reg->var_off)) {
10799 "R%d doesn't have constant offset. %s has to be at the constant offset\n",
10800 regno, node_type_name);
10804 node_off = reg->off + reg->var_off.value;
10805 field = reg_find_field_offset(reg, node_off, node_field_type);
10806 if (!field || field->offset != node_off) {
10807 verbose(env, "%s not found at offset=%u\n", node_type_name, node_off);
10811 field = *node_field;
10813 et = btf_type_by_id(field->graph_root.btf, field->graph_root.value_btf_id);
10814 t = btf_type_by_id(reg->btf, reg->btf_id);
10815 if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, 0, field->graph_root.btf,
10816 field->graph_root.value_btf_id, true)) {
10817 verbose(env, "operation on %s expects arg#1 %s at offset=%d "
10818 "in struct %s, but arg is at offset=%d in struct %s\n",
10819 btf_field_type_name(head_field_type),
10820 btf_field_type_name(node_field_type),
10821 field->graph_root.node_offset,
10822 btf_name_by_offset(field->graph_root.btf, et->name_off),
10823 node_off, btf_name_by_offset(reg->btf, t->name_off));
10826 meta->arg_btf = reg->btf;
10827 meta->arg_btf_id = reg->btf_id;
10829 if (node_off != field->graph_root.node_offset) {
10830 verbose(env, "arg#1 offset=%d, but expected %s at offset=%d in struct %s\n",
10831 node_off, btf_field_type_name(node_field_type),
10832 field->graph_root.node_offset,
10833 btf_name_by_offset(field->graph_root.btf, et->name_off));
10840 static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env,
10841 struct bpf_reg_state *reg, u32 regno,
10842 struct bpf_kfunc_call_arg_meta *meta)
10844 return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
10845 BPF_LIST_HEAD, BPF_LIST_NODE,
10846 &meta->arg_list_head.field);
10849 static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env,
10850 struct bpf_reg_state *reg, u32 regno,
10851 struct bpf_kfunc_call_arg_meta *meta)
10853 return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
10854 BPF_RB_ROOT, BPF_RB_NODE,
10855 &meta->arg_rbtree_root.field);
10858 static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta,
10861 const char *func_name = meta->func_name, *ref_tname;
10862 const struct btf *btf = meta->btf;
10863 const struct btf_param *args;
10864 struct btf_record *rec;
10868 args = (const struct btf_param *)(meta->func_proto + 1);
10869 nargs = btf_type_vlen(meta->func_proto);
10870 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
10871 verbose(env, "Function %s has %d > %d args\n", func_name, nargs,
10872 MAX_BPF_FUNC_REG_ARGS);
10876 /* Check that BTF function arguments match actual types that the
10879 for (i = 0; i < nargs; i++) {
10880 struct bpf_reg_state *regs = cur_regs(env), *reg = ®s[i + 1];
10881 const struct btf_type *t, *ref_t, *resolve_ret;
10882 enum bpf_arg_type arg_type = ARG_DONTCARE;
10883 u32 regno = i + 1, ref_id, type_size;
10884 bool is_ret_buf_sz = false;
10887 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
10889 if (is_kfunc_arg_ignore(btf, &args[i]))
10892 if (btf_type_is_scalar(t)) {
10893 if (reg->type != SCALAR_VALUE) {
10894 verbose(env, "R%d is not a scalar\n", regno);
10898 if (is_kfunc_arg_constant(meta->btf, &args[i])) {
10899 if (meta->arg_constant.found) {
10900 verbose(env, "verifier internal error: only one constant argument permitted\n");
10903 if (!tnum_is_const(reg->var_off)) {
10904 verbose(env, "R%d must be a known constant\n", regno);
10907 ret = mark_chain_precision(env, regno);
10910 meta->arg_constant.found = true;
10911 meta->arg_constant.value = reg->var_off.value;
10912 } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) {
10913 meta->r0_rdonly = true;
10914 is_ret_buf_sz = true;
10915 } else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) {
10916 is_ret_buf_sz = true;
10919 if (is_ret_buf_sz) {
10920 if (meta->r0_size) {
10921 verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
10925 if (!tnum_is_const(reg->var_off)) {
10926 verbose(env, "R%d is not a const\n", regno);
10930 meta->r0_size = reg->var_off.value;
10931 ret = mark_chain_precision(env, regno);
10938 if (!btf_type_is_ptr(t)) {
10939 verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t));
10943 if ((is_kfunc_trusted_args(meta) || is_kfunc_rcu(meta)) &&
10944 (register_is_null(reg) || type_may_be_null(reg->type))) {
10945 verbose(env, "Possibly NULL pointer passed to trusted arg%d\n", i);
10949 if (reg->ref_obj_id) {
10950 if (is_kfunc_release(meta) && meta->ref_obj_id) {
10951 verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
10952 regno, reg->ref_obj_id,
10956 meta->ref_obj_id = reg->ref_obj_id;
10957 if (is_kfunc_release(meta))
10958 meta->release_regno = regno;
10961 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
10962 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
10964 kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs);
10965 if (kf_arg_type < 0)
10966 return kf_arg_type;
10968 switch (kf_arg_type) {
10969 case KF_ARG_PTR_TO_ALLOC_BTF_ID:
10970 case KF_ARG_PTR_TO_BTF_ID:
10971 if (!is_kfunc_trusted_args(meta) && !is_kfunc_rcu(meta))
10974 if (!is_trusted_reg(reg)) {
10975 if (!is_kfunc_rcu(meta)) {
10976 verbose(env, "R%d must be referenced or trusted\n", regno);
10979 if (!is_rcu_reg(reg)) {
10980 verbose(env, "R%d must be a rcu pointer\n", regno);
10986 case KF_ARG_PTR_TO_CTX:
10987 /* Trusted arguments have the same offset checks as release arguments */
10988 arg_type |= OBJ_RELEASE;
10990 case KF_ARG_PTR_TO_DYNPTR:
10991 case KF_ARG_PTR_TO_ITER:
10992 case KF_ARG_PTR_TO_LIST_HEAD:
10993 case KF_ARG_PTR_TO_LIST_NODE:
10994 case KF_ARG_PTR_TO_RB_ROOT:
10995 case KF_ARG_PTR_TO_RB_NODE:
10996 case KF_ARG_PTR_TO_MEM:
10997 case KF_ARG_PTR_TO_MEM_SIZE:
10998 case KF_ARG_PTR_TO_CALLBACK:
10999 case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
11000 /* Trusted by default */
11007 if (is_kfunc_release(meta) && reg->ref_obj_id)
11008 arg_type |= OBJ_RELEASE;
11009 ret = check_func_arg_reg_off(env, reg, regno, arg_type);
11013 switch (kf_arg_type) {
11014 case KF_ARG_PTR_TO_CTX:
11015 if (reg->type != PTR_TO_CTX) {
11016 verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t));
11020 if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
11021 ret = get_kern_ctx_btf_id(&env->log, resolve_prog_type(env->prog));
11024 meta->ret_btf_id = ret;
11027 case KF_ARG_PTR_TO_ALLOC_BTF_ID:
11028 if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
11029 verbose(env, "arg#%d expected pointer to allocated object\n", i);
11032 if (!reg->ref_obj_id) {
11033 verbose(env, "allocated object must be referenced\n");
11036 if (meta->btf == btf_vmlinux &&
11037 meta->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
11038 meta->arg_btf = reg->btf;
11039 meta->arg_btf_id = reg->btf_id;
11042 case KF_ARG_PTR_TO_DYNPTR:
11044 enum bpf_arg_type dynptr_arg_type = ARG_PTR_TO_DYNPTR;
11045 int clone_ref_obj_id = 0;
11047 if (reg->type != PTR_TO_STACK &&
11048 reg->type != CONST_PTR_TO_DYNPTR) {
11049 verbose(env, "arg#%d expected pointer to stack or dynptr_ptr\n", i);
11053 if (reg->type == CONST_PTR_TO_DYNPTR)
11054 dynptr_arg_type |= MEM_RDONLY;
11056 if (is_kfunc_arg_uninit(btf, &args[i]))
11057 dynptr_arg_type |= MEM_UNINIT;
11059 if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
11060 dynptr_arg_type |= DYNPTR_TYPE_SKB;
11061 } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_xdp]) {
11062 dynptr_arg_type |= DYNPTR_TYPE_XDP;
11063 } else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_clone] &&
11064 (dynptr_arg_type & MEM_UNINIT)) {
11065 enum bpf_dynptr_type parent_type = meta->initialized_dynptr.type;
11067 if (parent_type == BPF_DYNPTR_TYPE_INVALID) {
11068 verbose(env, "verifier internal error: no dynptr type for parent of clone\n");
11072 dynptr_arg_type |= (unsigned int)get_dynptr_type_flag(parent_type);
11073 clone_ref_obj_id = meta->initialized_dynptr.ref_obj_id;
11074 if (dynptr_type_refcounted(parent_type) && !clone_ref_obj_id) {
11075 verbose(env, "verifier internal error: missing ref obj id for parent of clone\n");
11080 ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type, clone_ref_obj_id);
11084 if (!(dynptr_arg_type & MEM_UNINIT)) {
11085 int id = dynptr_id(env, reg);
11088 verbose(env, "verifier internal error: failed to obtain dynptr id\n");
11091 meta->initialized_dynptr.id = id;
11092 meta->initialized_dynptr.type = dynptr_get_type(env, reg);
11093 meta->initialized_dynptr.ref_obj_id = dynptr_ref_obj_id(env, reg);
11098 case KF_ARG_PTR_TO_ITER:
11099 ret = process_iter_arg(env, regno, insn_idx, meta);
11103 case KF_ARG_PTR_TO_LIST_HEAD:
11104 if (reg->type != PTR_TO_MAP_VALUE &&
11105 reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
11106 verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
11109 if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
11110 verbose(env, "allocated object must be referenced\n");
11113 ret = process_kf_arg_ptr_to_list_head(env, reg, regno, meta);
11117 case KF_ARG_PTR_TO_RB_ROOT:
11118 if (reg->type != PTR_TO_MAP_VALUE &&
11119 reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
11120 verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
11123 if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
11124 verbose(env, "allocated object must be referenced\n");
11127 ret = process_kf_arg_ptr_to_rbtree_root(env, reg, regno, meta);
11131 case KF_ARG_PTR_TO_LIST_NODE:
11132 if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
11133 verbose(env, "arg#%d expected pointer to allocated object\n", i);
11136 if (!reg->ref_obj_id) {
11137 verbose(env, "allocated object must be referenced\n");
11140 ret = process_kf_arg_ptr_to_list_node(env, reg, regno, meta);
11144 case KF_ARG_PTR_TO_RB_NODE:
11145 if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_remove]) {
11146 if (!type_is_non_owning_ref(reg->type) || reg->ref_obj_id) {
11147 verbose(env, "rbtree_remove node input must be non-owning ref\n");
11150 if (in_rbtree_lock_required_cb(env)) {
11151 verbose(env, "rbtree_remove not allowed in rbtree cb\n");
11155 if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
11156 verbose(env, "arg#%d expected pointer to allocated object\n", i);
11159 if (!reg->ref_obj_id) {
11160 verbose(env, "allocated object must be referenced\n");
11165 ret = process_kf_arg_ptr_to_rbtree_node(env, reg, regno, meta);
11169 case KF_ARG_PTR_TO_BTF_ID:
11170 /* Only base_type is checked, further checks are done here */
11171 if ((base_type(reg->type) != PTR_TO_BTF_ID ||
11172 (bpf_type_has_unsafe_modifiers(reg->type) && !is_rcu_reg(reg))) &&
11173 !reg2btf_ids[base_type(reg->type)]) {
11174 verbose(env, "arg#%d is %s ", i, reg_type_str(env, reg->type));
11175 verbose(env, "expected %s or socket\n",
11176 reg_type_str(env, base_type(reg->type) |
11177 (type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS)));
11180 ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i);
11184 case KF_ARG_PTR_TO_MEM:
11185 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
11186 if (IS_ERR(resolve_ret)) {
11187 verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
11188 i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret));
11191 ret = check_mem_reg(env, reg, regno, type_size);
11195 case KF_ARG_PTR_TO_MEM_SIZE:
11197 struct bpf_reg_state *buff_reg = ®s[regno];
11198 const struct btf_param *buff_arg = &args[i];
11199 struct bpf_reg_state *size_reg = ®s[regno + 1];
11200 const struct btf_param *size_arg = &args[i + 1];
11202 if (!register_is_null(buff_reg) || !is_kfunc_arg_optional(meta->btf, buff_arg)) {
11203 ret = check_kfunc_mem_size_reg(env, size_reg, regno + 1);
11205 verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1);
11210 if (is_kfunc_arg_const_mem_size(meta->btf, size_arg, size_reg)) {
11211 if (meta->arg_constant.found) {
11212 verbose(env, "verifier internal error: only one constant argument permitted\n");
11215 if (!tnum_is_const(size_reg->var_off)) {
11216 verbose(env, "R%d must be a known constant\n", regno + 1);
11219 meta->arg_constant.found = true;
11220 meta->arg_constant.value = size_reg->var_off.value;
11223 /* Skip next '__sz' or '__szk' argument */
11227 case KF_ARG_PTR_TO_CALLBACK:
11228 if (reg->type != PTR_TO_FUNC) {
11229 verbose(env, "arg%d expected pointer to func\n", i);
11232 meta->subprogno = reg->subprogno;
11234 case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
11235 if (!type_is_ptr_alloc_obj(reg->type)) {
11236 verbose(env, "arg#%d is neither owning or non-owning ref\n", i);
11239 if (!type_is_non_owning_ref(reg->type))
11240 meta->arg_owning_ref = true;
11242 rec = reg_btf_record(reg);
11244 verbose(env, "verifier internal error: Couldn't find btf_record\n");
11248 if (rec->refcount_off < 0) {
11249 verbose(env, "arg#%d doesn't point to a type with bpf_refcount field\n", i);
11253 meta->arg_btf = reg->btf;
11254 meta->arg_btf_id = reg->btf_id;
11259 if (is_kfunc_release(meta) && !meta->release_regno) {
11260 verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
11268 static int fetch_kfunc_meta(struct bpf_verifier_env *env,
11269 struct bpf_insn *insn,
11270 struct bpf_kfunc_call_arg_meta *meta,
11271 const char **kfunc_name)
11273 const struct btf_type *func, *func_proto;
11274 u32 func_id, *kfunc_flags;
11275 const char *func_name;
11276 struct btf *desc_btf;
11279 *kfunc_name = NULL;
11284 desc_btf = find_kfunc_desc_btf(env, insn->off);
11285 if (IS_ERR(desc_btf))
11286 return PTR_ERR(desc_btf);
11288 func_id = insn->imm;
11289 func = btf_type_by_id(desc_btf, func_id);
11290 func_name = btf_name_by_offset(desc_btf, func->name_off);
11292 *kfunc_name = func_name;
11293 func_proto = btf_type_by_id(desc_btf, func->type);
11295 kfunc_flags = btf_kfunc_id_set_contains(desc_btf, func_id, env->prog);
11296 if (!kfunc_flags) {
11300 memset(meta, 0, sizeof(*meta));
11301 meta->btf = desc_btf;
11302 meta->func_id = func_id;
11303 meta->kfunc_flags = *kfunc_flags;
11304 meta->func_proto = func_proto;
11305 meta->func_name = func_name;
11310 static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
11313 const struct btf_type *t, *ptr_type;
11314 u32 i, nargs, ptr_type_id, release_ref_obj_id;
11315 struct bpf_reg_state *regs = cur_regs(env);
11316 const char *func_name, *ptr_type_name;
11317 bool sleepable, rcu_lock, rcu_unlock;
11318 struct bpf_kfunc_call_arg_meta meta;
11319 struct bpf_insn_aux_data *insn_aux;
11320 int err, insn_idx = *insn_idx_p;
11321 const struct btf_param *args;
11322 const struct btf_type *ret_t;
11323 struct btf *desc_btf;
11325 /* skip for now, but return error when we find this in fixup_kfunc_call */
11329 err = fetch_kfunc_meta(env, insn, &meta, &func_name);
11330 if (err == -EACCES && func_name)
11331 verbose(env, "calling kernel function %s is not allowed\n", func_name);
11334 desc_btf = meta.btf;
11335 insn_aux = &env->insn_aux_data[insn_idx];
11337 insn_aux->is_iter_next = is_iter_next_kfunc(&meta);
11339 if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
11340 verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
11344 sleepable = is_kfunc_sleepable(&meta);
11345 if (sleepable && !env->prog->aux->sleepable) {
11346 verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
11350 rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta);
11351 rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);
11353 if (env->cur_state->active_rcu_lock) {
11354 struct bpf_func_state *state;
11355 struct bpf_reg_state *reg;
11357 if (in_rbtree_lock_required_cb(env) && (rcu_lock || rcu_unlock)) {
11358 verbose(env, "Calling bpf_rcu_read_{lock,unlock} in unnecessary rbtree callback\n");
11363 verbose(env, "nested rcu read lock (kernel function %s)\n", func_name);
11365 } else if (rcu_unlock) {
11366 bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
11367 if (reg->type & MEM_RCU) {
11368 reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL);
11369 reg->type |= PTR_UNTRUSTED;
11372 env->cur_state->active_rcu_lock = false;
11373 } else if (sleepable) {
11374 verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name);
11377 } else if (rcu_lock) {
11378 env->cur_state->active_rcu_lock = true;
11379 } else if (rcu_unlock) {
11380 verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name);
11384 /* Check the arguments */
11385 err = check_kfunc_args(env, &meta, insn_idx);
11388 /* In case of release function, we get register number of refcounted
11389 * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
11391 if (meta.release_regno) {
11392 err = release_reference(env, regs[meta.release_regno].ref_obj_id);
11394 verbose(env, "kfunc %s#%d reference has not been acquired before\n",
11395 func_name, meta.func_id);
11400 if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
11401 meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
11402 meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
11403 release_ref_obj_id = regs[BPF_REG_2].ref_obj_id;
11404 insn_aux->insert_off = regs[BPF_REG_2].off;
11405 insn_aux->kptr_struct_meta = btf_find_struct_meta(meta.arg_btf, meta.arg_btf_id);
11406 err = ref_convert_owning_non_owning(env, release_ref_obj_id);
11408 verbose(env, "kfunc %s#%d conversion of owning ref to non-owning failed\n",
11409 func_name, meta.func_id);
11413 err = release_reference(env, release_ref_obj_id);
11415 verbose(env, "kfunc %s#%d reference has not been acquired before\n",
11416 func_name, meta.func_id);
11421 if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
11422 err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
11423 set_rbtree_add_callback_state);
11425 verbose(env, "kfunc %s#%d failed callback verification\n",
11426 func_name, meta.func_id);
11431 for (i = 0; i < CALLER_SAVED_REGS; i++)
11432 mark_reg_not_init(env, regs, caller_saved[i]);
11434 /* Check return type */
11435 t = btf_type_skip_modifiers(desc_btf, meta.func_proto->type, NULL);
11437 if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
11438 /* Only exception is bpf_obj_new_impl */
11439 if (meta.btf != btf_vmlinux ||
11440 (meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl] &&
11441 meta.func_id != special_kfunc_list[KF_bpf_refcount_acquire_impl])) {
11442 verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
11447 if (btf_type_is_scalar(t)) {
11448 mark_reg_unknown(env, regs, BPF_REG_0);
11449 mark_btf_func_reg_size(env, BPF_REG_0, t->size);
11450 } else if (btf_type_is_ptr(t)) {
11451 ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id);
11453 if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
11454 if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
11455 struct btf *ret_btf;
11458 if (unlikely(!bpf_global_ma_set))
11461 if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
11462 verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
11466 ret_btf = env->prog->aux->btf;
11467 ret_btf_id = meta.arg_constant.value;
11469 /* This may be NULL due to user not supplying a BTF */
11471 verbose(env, "bpf_obj_new requires prog BTF\n");
11475 ret_t = btf_type_by_id(ret_btf, ret_btf_id);
11476 if (!ret_t || !__btf_type_is_struct(ret_t)) {
11477 verbose(env, "bpf_obj_new type ID argument must be of a struct\n");
11481 mark_reg_known_zero(env, regs, BPF_REG_0);
11482 regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
11483 regs[BPF_REG_0].btf = ret_btf;
11484 regs[BPF_REG_0].btf_id = ret_btf_id;
11486 insn_aux->obj_new_size = ret_t->size;
11487 insn_aux->kptr_struct_meta =
11488 btf_find_struct_meta(ret_btf, ret_btf_id);
11489 } else if (meta.func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
11490 mark_reg_known_zero(env, regs, BPF_REG_0);
11491 regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
11492 regs[BPF_REG_0].btf = meta.arg_btf;
11493 regs[BPF_REG_0].btf_id = meta.arg_btf_id;
11495 insn_aux->kptr_struct_meta =
11496 btf_find_struct_meta(meta.arg_btf,
11498 } else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] ||
11499 meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) {
11500 struct btf_field *field = meta.arg_list_head.field;
11502 mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
11503 } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
11504 meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
11505 struct btf_field *field = meta.arg_rbtree_root.field;
11507 mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
11508 } else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
11509 mark_reg_known_zero(env, regs, BPF_REG_0);
11510 regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED;
11511 regs[BPF_REG_0].btf = desc_btf;
11512 regs[BPF_REG_0].btf_id = meta.ret_btf_id;
11513 } else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
11514 ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value);
11515 if (!ret_t || !btf_type_is_struct(ret_t)) {
11517 "kfunc bpf_rdonly_cast type ID argument must be of a struct\n");
11521 mark_reg_known_zero(env, regs, BPF_REG_0);
11522 regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
11523 regs[BPF_REG_0].btf = desc_btf;
11524 regs[BPF_REG_0].btf_id = meta.arg_constant.value;
11525 } else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] ||
11526 meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
11527 enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type);
11529 mark_reg_known_zero(env, regs, BPF_REG_0);
11531 if (!meta.arg_constant.found) {
11532 verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n");
11536 regs[BPF_REG_0].mem_size = meta.arg_constant.value;
11538 /* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */
11539 regs[BPF_REG_0].type = PTR_TO_MEM | type_flag;
11541 if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) {
11542 regs[BPF_REG_0].type |= MEM_RDONLY;
11544 /* this will set env->seen_direct_write to true */
11545 if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) {
11546 verbose(env, "the prog does not allow writes to packet data\n");
11551 if (!meta.initialized_dynptr.id) {
11552 verbose(env, "verifier internal error: no dynptr id\n");
11555 regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id;
11557 /* we don't need to set BPF_REG_0's ref obj id
11558 * because packet slices are not refcounted (see
11559 * dynptr_type_refcounted)
11562 verbose(env, "kernel function %s unhandled dynamic return type\n",
11566 } else if (!__btf_type_is_struct(ptr_type)) {
11567 if (!meta.r0_size) {
11570 if (!IS_ERR(btf_resolve_size(desc_btf, ptr_type, &sz))) {
11572 meta.r0_rdonly = true;
11575 if (!meta.r0_size) {
11576 ptr_type_name = btf_name_by_offset(desc_btf,
11577 ptr_type->name_off);
11579 "kernel function %s returns pointer type %s %s is not supported\n",
11581 btf_type_str(ptr_type),
11586 mark_reg_known_zero(env, regs, BPF_REG_0);
11587 regs[BPF_REG_0].type = PTR_TO_MEM;
11588 regs[BPF_REG_0].mem_size = meta.r0_size;
11590 if (meta.r0_rdonly)
11591 regs[BPF_REG_0].type |= MEM_RDONLY;
11593 /* Ensures we don't access the memory after a release_reference() */
11594 if (meta.ref_obj_id)
11595 regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
11597 mark_reg_known_zero(env, regs, BPF_REG_0);
11598 regs[BPF_REG_0].btf = desc_btf;
11599 regs[BPF_REG_0].type = PTR_TO_BTF_ID;
11600 regs[BPF_REG_0].btf_id = ptr_type_id;
11603 if (is_kfunc_ret_null(&meta)) {
11604 regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
11605 /* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
11606 regs[BPF_REG_0].id = ++env->id_gen;
11608 mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
11609 if (is_kfunc_acquire(&meta)) {
11610 int id = acquire_reference_state(env, insn_idx);
11614 if (is_kfunc_ret_null(&meta))
11615 regs[BPF_REG_0].id = id;
11616 regs[BPF_REG_0].ref_obj_id = id;
11617 } else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
11618 ref_set_non_owning(env, ®s[BPF_REG_0]);
11621 if (reg_may_point_to_spin_lock(®s[BPF_REG_0]) && !regs[BPF_REG_0].id)
11622 regs[BPF_REG_0].id = ++env->id_gen;
11623 } else if (btf_type_is_void(t)) {
11624 if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
11625 if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
11626 insn_aux->kptr_struct_meta =
11627 btf_find_struct_meta(meta.arg_btf,
11633 nargs = btf_type_vlen(meta.func_proto);
11634 args = (const struct btf_param *)(meta.func_proto + 1);
11635 for (i = 0; i < nargs; i++) {
11638 t = btf_type_skip_modifiers(desc_btf, args[i].type, NULL);
11639 if (btf_type_is_ptr(t))
11640 mark_btf_func_reg_size(env, regno, sizeof(void *));
11642 /* scalar. ensured by btf_check_kfunc_arg_match() */
11643 mark_btf_func_reg_size(env, regno, t->size);
11646 if (is_iter_next_kfunc(&meta)) {
11647 err = process_iter_next_call(env, insn_idx, &meta);
11655 static bool signed_add_overflows(s64 a, s64 b)
11657 /* Do the add in u64, where overflow is well-defined */
11658 s64 res = (s64)((u64)a + (u64)b);
11665 static bool signed_add32_overflows(s32 a, s32 b)
11667 /* Do the add in u32, where overflow is well-defined */
11668 s32 res = (s32)((u32)a + (u32)b);
11675 static bool signed_sub_overflows(s64 a, s64 b)
11677 /* Do the sub in u64, where overflow is well-defined */
11678 s64 res = (s64)((u64)a - (u64)b);
11685 static bool signed_sub32_overflows(s32 a, s32 b)
11687 /* Do the sub in u32, where overflow is well-defined */
11688 s32 res = (s32)((u32)a - (u32)b);
11695 static bool check_reg_sane_offset(struct bpf_verifier_env *env,
11696 const struct bpf_reg_state *reg,
11697 enum bpf_reg_type type)
11699 bool known = tnum_is_const(reg->var_off);
11700 s64 val = reg->var_off.value;
11701 s64 smin = reg->smin_value;
11703 if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
11704 verbose(env, "math between %s pointer and %lld is not allowed\n",
11705 reg_type_str(env, type), val);
11709 if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
11710 verbose(env, "%s pointer offset %d is not allowed\n",
11711 reg_type_str(env, type), reg->off);
11715 if (smin == S64_MIN) {
11716 verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
11717 reg_type_str(env, type));
11721 if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
11722 verbose(env, "value %lld makes %s pointer be out of bounds\n",
11723 smin, reg_type_str(env, type));
11731 REASON_BOUNDS = -1,
11738 static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
11739 u32 *alu_limit, bool mask_to_left)
11741 u32 max = 0, ptr_limit = 0;
11743 switch (ptr_reg->type) {
11745 /* Offset 0 is out-of-bounds, but acceptable start for the
11746 * left direction, see BPF_REG_FP. Also, unknown scalar
11747 * offset where we would need to deal with min/max bounds is
11748 * currently prohibited for unprivileged.
11750 max = MAX_BPF_STACK + mask_to_left;
11751 ptr_limit = -(ptr_reg->var_off.value + ptr_reg->off);
11753 case PTR_TO_MAP_VALUE:
11754 max = ptr_reg->map_ptr->value_size;
11755 ptr_limit = (mask_to_left ?
11756 ptr_reg->smin_value :
11757 ptr_reg->umax_value) + ptr_reg->off;
11760 return REASON_TYPE;
11763 if (ptr_limit >= max)
11764 return REASON_LIMIT;
11765 *alu_limit = ptr_limit;
11769 static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
11770 const struct bpf_insn *insn)
11772 return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K;
11775 static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
11776 u32 alu_state, u32 alu_limit)
11778 /* If we arrived here from different branches with different
11779 * state or limits to sanitize, then this won't work.
11781 if (aux->alu_state &&
11782 (aux->alu_state != alu_state ||
11783 aux->alu_limit != alu_limit))
11784 return REASON_PATHS;
11786 /* Corresponding fixup done in do_misc_fixups(). */
11787 aux->alu_state = alu_state;
11788 aux->alu_limit = alu_limit;
11792 static int sanitize_val_alu(struct bpf_verifier_env *env,
11793 struct bpf_insn *insn)
11795 struct bpf_insn_aux_data *aux = cur_aux(env);
11797 if (can_skip_alu_sanitation(env, insn))
11800 return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
11803 static bool sanitize_needed(u8 opcode)
11805 return opcode == BPF_ADD || opcode == BPF_SUB;
11808 struct bpf_sanitize_info {
11809 struct bpf_insn_aux_data aux;
11813 static struct bpf_verifier_state *
11814 sanitize_speculative_path(struct bpf_verifier_env *env,
11815 const struct bpf_insn *insn,
11816 u32 next_idx, u32 curr_idx)
11818 struct bpf_verifier_state *branch;
11819 struct bpf_reg_state *regs;
11821 branch = push_stack(env, next_idx, curr_idx, true);
11822 if (branch && insn) {
11823 regs = branch->frame[branch->curframe]->regs;
11824 if (BPF_SRC(insn->code) == BPF_K) {
11825 mark_reg_unknown(env, regs, insn->dst_reg);
11826 } else if (BPF_SRC(insn->code) == BPF_X) {
11827 mark_reg_unknown(env, regs, insn->dst_reg);
11828 mark_reg_unknown(env, regs, insn->src_reg);
11834 static int sanitize_ptr_alu(struct bpf_verifier_env *env,
11835 struct bpf_insn *insn,
11836 const struct bpf_reg_state *ptr_reg,
11837 const struct bpf_reg_state *off_reg,
11838 struct bpf_reg_state *dst_reg,
11839 struct bpf_sanitize_info *info,
11840 const bool commit_window)
11842 struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
11843 struct bpf_verifier_state *vstate = env->cur_state;
11844 bool off_is_imm = tnum_is_const(off_reg->var_off);
11845 bool off_is_neg = off_reg->smin_value < 0;
11846 bool ptr_is_dst_reg = ptr_reg == dst_reg;
11847 u8 opcode = BPF_OP(insn->code);
11848 u32 alu_state, alu_limit;
11849 struct bpf_reg_state tmp;
11853 if (can_skip_alu_sanitation(env, insn))
11856 /* We already marked aux for masking from non-speculative
11857 * paths, thus we got here in the first place. We only care
11858 * to explore bad access from here.
11860 if (vstate->speculative)
11863 if (!commit_window) {
11864 if (!tnum_is_const(off_reg->var_off) &&
11865 (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
11866 return REASON_BOUNDS;
11868 info->mask_to_left = (opcode == BPF_ADD && off_is_neg) ||
11869 (opcode == BPF_SUB && !off_is_neg);
11872 err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
11876 if (commit_window) {
11877 /* In commit phase we narrow the masking window based on
11878 * the observed pointer move after the simulated operation.
11880 alu_state = info->aux.alu_state;
11881 alu_limit = abs(info->aux.alu_limit - alu_limit);
11883 alu_state = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
11884 alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
11885 alu_state |= ptr_is_dst_reg ?
11886 BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
11888 /* Limit pruning on unknown scalars to enable deep search for
11889 * potential masking differences from other program paths.
11892 env->explore_alu_limits = true;
11895 err = update_alu_sanitation_state(aux, alu_state, alu_limit);
11899 /* If we're in commit phase, we're done here given we already
11900 * pushed the truncated dst_reg into the speculative verification
11903 * Also, when register is a known constant, we rewrite register-based
11904 * operation to immediate-based, and thus do not need masking (and as
11905 * a consequence, do not need to simulate the zero-truncation either).
11907 if (commit_window || off_is_imm)
11910 /* Simulate and find potential out-of-bounds access under
11911 * speculative execution from truncation as a result of
11912 * masking when off was not within expected range. If off
11913 * sits in dst, then we temporarily need to move ptr there
11914 * to simulate dst (== 0) +/-= ptr. Needed, for example,
11915 * for cases where we use K-based arithmetic in one direction
11916 * and truncated reg-based in the other in order to explore
11919 if (!ptr_is_dst_reg) {
11921 copy_register_state(dst_reg, ptr_reg);
11923 ret = sanitize_speculative_path(env, NULL, env->insn_idx + 1,
11925 if (!ptr_is_dst_reg && ret)
11927 return !ret ? REASON_STACK : 0;
11930 static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
11932 struct bpf_verifier_state *vstate = env->cur_state;
11934 /* If we simulate paths under speculation, we don't update the
11935 * insn as 'seen' such that when we verify unreachable paths in
11936 * the non-speculative domain, sanitize_dead_code() can still
11937 * rewrite/sanitize them.
11939 if (!vstate->speculative)
11940 env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
11943 static int sanitize_err(struct bpf_verifier_env *env,
11944 const struct bpf_insn *insn, int reason,
11945 const struct bpf_reg_state *off_reg,
11946 const struct bpf_reg_state *dst_reg)
11948 static const char *err = "pointer arithmetic with it prohibited for !root";
11949 const char *op = BPF_OP(insn->code) == BPF_ADD ? "add" : "sub";
11950 u32 dst = insn->dst_reg, src = insn->src_reg;
11953 case REASON_BOUNDS:
11954 verbose(env, "R%d has unknown scalar with mixed signed bounds, %s\n",
11955 off_reg == dst_reg ? dst : src, err);
11958 verbose(env, "R%d has pointer with unsupported alu operation, %s\n",
11959 off_reg == dst_reg ? src : dst, err);
11962 verbose(env, "R%d tried to %s from different maps, paths or scalars, %s\n",
11966 verbose(env, "R%d tried to %s beyond pointer bounds, %s\n",
11970 verbose(env, "R%d could not be pushed for speculative verification, %s\n",
11974 verbose(env, "verifier internal error: unknown reason (%d)\n",
11982 /* check that stack access falls within stack limits and that 'reg' doesn't
11983 * have a variable offset.
11985 * Variable offset is prohibited for unprivileged mode for simplicity since it
11986 * requires corresponding support in Spectre masking for stack ALU. See also
11987 * retrieve_ptr_limit().
11990 * 'off' includes 'reg->off'.
11992 static int check_stack_access_for_ptr_arithmetic(
11993 struct bpf_verifier_env *env,
11995 const struct bpf_reg_state *reg,
11998 if (!tnum_is_const(reg->var_off)) {
12001 tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
12002 verbose(env, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n",
12003 regno, tn_buf, off);
12007 if (off >= 0 || off < -MAX_BPF_STACK) {
12008 verbose(env, "R%d stack pointer arithmetic goes out of range, "
12009 "prohibited for !root; off=%d\n", regno, off);
12016 static int sanitize_check_bounds(struct bpf_verifier_env *env,
12017 const struct bpf_insn *insn,
12018 const struct bpf_reg_state *dst_reg)
12020 u32 dst = insn->dst_reg;
12022 /* For unprivileged we require that resulting offset must be in bounds
12023 * in order to be able to sanitize access later on.
12025 if (env->bypass_spec_v1)
12028 switch (dst_reg->type) {
12030 if (check_stack_access_for_ptr_arithmetic(env, dst, dst_reg,
12031 dst_reg->off + dst_reg->var_off.value))
12034 case PTR_TO_MAP_VALUE:
12035 if (check_map_access(env, dst, dst_reg->off, 1, false, ACCESS_HELPER)) {
12036 verbose(env, "R%d pointer arithmetic of map value goes out of range, "
12037 "prohibited for !root\n", dst);
12048 /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
12049 * Caller should also handle BPF_MOV case separately.
12050 * If we return -EACCES, caller may want to try again treating pointer as a
12051 * scalar. So we only emit a diagnostic if !env->allow_ptr_leaks.
12053 static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
12054 struct bpf_insn *insn,
12055 const struct bpf_reg_state *ptr_reg,
12056 const struct bpf_reg_state *off_reg)
12058 struct bpf_verifier_state *vstate = env->cur_state;
12059 struct bpf_func_state *state = vstate->frame[vstate->curframe];
12060 struct bpf_reg_state *regs = state->regs, *dst_reg;
12061 bool known = tnum_is_const(off_reg->var_off);
12062 s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
12063 smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
12064 u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
12065 umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
12066 struct bpf_sanitize_info info = {};
12067 u8 opcode = BPF_OP(insn->code);
12068 u32 dst = insn->dst_reg;
12071 dst_reg = ®s[dst];
12073 if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
12074 smin_val > smax_val || umin_val > umax_val) {
12075 /* Taint dst register if offset had invalid bounds derived from
12076 * e.g. dead branches.
12078 __mark_reg_unknown(env, dst_reg);
12082 if (BPF_CLASS(insn->code) != BPF_ALU64) {
12083 /* 32-bit ALU ops on pointers produce (meaningless) scalars */
12084 if (opcode == BPF_SUB && env->allow_ptr_leaks) {
12085 __mark_reg_unknown(env, dst_reg);
12090 "R%d 32-bit pointer arithmetic prohibited\n",
12095 if (ptr_reg->type & PTR_MAYBE_NULL) {
12096 verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
12097 dst, reg_type_str(env, ptr_reg->type));
12101 switch (base_type(ptr_reg->type)) {
12102 case CONST_PTR_TO_MAP:
12103 /* smin_val represents the known value */
12104 if (known && smin_val == 0 && opcode == BPF_ADD)
12107 case PTR_TO_PACKET_END:
12108 case PTR_TO_SOCKET:
12109 case PTR_TO_SOCK_COMMON:
12110 case PTR_TO_TCP_SOCK:
12111 case PTR_TO_XDP_SOCK:
12112 verbose(env, "R%d pointer arithmetic on %s prohibited\n",
12113 dst, reg_type_str(env, ptr_reg->type));
12119 /* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
12120 * The id may be overwritten later if we create a new variable offset.
12122 dst_reg->type = ptr_reg->type;
12123 dst_reg->id = ptr_reg->id;
12125 if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
12126 !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
12129 /* pointer types do not carry 32-bit bounds at the moment. */
12130 __mark_reg32_unbounded(dst_reg);
12132 if (sanitize_needed(opcode)) {
12133 ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
12136 return sanitize_err(env, insn, ret, off_reg, dst_reg);
12141 /* We can take a fixed offset as long as it doesn't overflow
12142 * the s32 'off' field
12144 if (known && (ptr_reg->off + smin_val ==
12145 (s64)(s32)(ptr_reg->off + smin_val))) {
12146 /* pointer += K. Accumulate it into fixed offset */
12147 dst_reg->smin_value = smin_ptr;
12148 dst_reg->smax_value = smax_ptr;
12149 dst_reg->umin_value = umin_ptr;
12150 dst_reg->umax_value = umax_ptr;
12151 dst_reg->var_off = ptr_reg->var_off;
12152 dst_reg->off = ptr_reg->off + smin_val;
12153 dst_reg->raw = ptr_reg->raw;
12156 /* A new variable offset is created. Note that off_reg->off
12157 * == 0, since it's a scalar.
12158 * dst_reg gets the pointer type and since some positive
12159 * integer value was added to the pointer, give it a new 'id'
12160 * if it's a PTR_TO_PACKET.
12161 * this creates a new 'base' pointer, off_reg (variable) gets
12162 * added into the variable offset, and we copy the fixed offset
12165 if (signed_add_overflows(smin_ptr, smin_val) ||
12166 signed_add_overflows(smax_ptr, smax_val)) {
12167 dst_reg->smin_value = S64_MIN;
12168 dst_reg->smax_value = S64_MAX;
12170 dst_reg->smin_value = smin_ptr + smin_val;
12171 dst_reg->smax_value = smax_ptr + smax_val;
12173 if (umin_ptr + umin_val < umin_ptr ||
12174 umax_ptr + umax_val < umax_ptr) {
12175 dst_reg->umin_value = 0;
12176 dst_reg->umax_value = U64_MAX;
12178 dst_reg->umin_value = umin_ptr + umin_val;
12179 dst_reg->umax_value = umax_ptr + umax_val;
12181 dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
12182 dst_reg->off = ptr_reg->off;
12183 dst_reg->raw = ptr_reg->raw;
12184 if (reg_is_pkt_pointer(ptr_reg)) {
12185 dst_reg->id = ++env->id_gen;
12186 /* something was added to pkt_ptr, set range to zero */
12187 memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
12191 if (dst_reg == off_reg) {
12192 /* scalar -= pointer. Creates an unknown scalar */
12193 verbose(env, "R%d tried to subtract pointer from scalar\n",
12197 /* We don't allow subtraction from FP, because (according to
12198 * test_verifier.c test "invalid fp arithmetic", JITs might not
12199 * be able to deal with it.
12201 if (ptr_reg->type == PTR_TO_STACK) {
12202 verbose(env, "R%d subtraction from stack pointer prohibited\n",
12206 if (known && (ptr_reg->off - smin_val ==
12207 (s64)(s32)(ptr_reg->off - smin_val))) {
12208 /* pointer -= K. Subtract it from fixed offset */
12209 dst_reg->smin_value = smin_ptr;
12210 dst_reg->smax_value = smax_ptr;
12211 dst_reg->umin_value = umin_ptr;
12212 dst_reg->umax_value = umax_ptr;
12213 dst_reg->var_off = ptr_reg->var_off;
12214 dst_reg->id = ptr_reg->id;
12215 dst_reg->off = ptr_reg->off - smin_val;
12216 dst_reg->raw = ptr_reg->raw;
12219 /* A new variable offset is created. If the subtrahend is known
12220 * nonnegative, then any reg->range we had before is still good.
12222 if (signed_sub_overflows(smin_ptr, smax_val) ||
12223 signed_sub_overflows(smax_ptr, smin_val)) {
12224 /* Overflow possible, we know nothing */
12225 dst_reg->smin_value = S64_MIN;
12226 dst_reg->smax_value = S64_MAX;
12228 dst_reg->smin_value = smin_ptr - smax_val;
12229 dst_reg->smax_value = smax_ptr - smin_val;
12231 if (umin_ptr < umax_val) {
12232 /* Overflow possible, we know nothing */
12233 dst_reg->umin_value = 0;
12234 dst_reg->umax_value = U64_MAX;
12236 /* Cannot overflow (as long as bounds are consistent) */
12237 dst_reg->umin_value = umin_ptr - umax_val;
12238 dst_reg->umax_value = umax_ptr - umin_val;
12240 dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
12241 dst_reg->off = ptr_reg->off;
12242 dst_reg->raw = ptr_reg->raw;
12243 if (reg_is_pkt_pointer(ptr_reg)) {
12244 dst_reg->id = ++env->id_gen;
12245 /* something was added to pkt_ptr, set range to zero */
12247 memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
12253 /* bitwise ops on pointers are troublesome, prohibit. */
12254 verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
12255 dst, bpf_alu_string[opcode >> 4]);
12258 /* other operators (e.g. MUL,LSH) produce non-pointer results */
12259 verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
12260 dst, bpf_alu_string[opcode >> 4]);
12264 if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
12266 reg_bounds_sync(dst_reg);
12267 if (sanitize_check_bounds(env, insn, dst_reg) < 0)
12269 if (sanitize_needed(opcode)) {
12270 ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
12273 return sanitize_err(env, insn, ret, off_reg, dst_reg);
12279 static void scalar32_min_max_add(struct bpf_reg_state *dst_reg,
12280 struct bpf_reg_state *src_reg)
12282 s32 smin_val = src_reg->s32_min_value;
12283 s32 smax_val = src_reg->s32_max_value;
12284 u32 umin_val = src_reg->u32_min_value;
12285 u32 umax_val = src_reg->u32_max_value;
12287 if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) ||
12288 signed_add32_overflows(dst_reg->s32_max_value, smax_val)) {
12289 dst_reg->s32_min_value = S32_MIN;
12290 dst_reg->s32_max_value = S32_MAX;
12292 dst_reg->s32_min_value += smin_val;
12293 dst_reg->s32_max_value += smax_val;
12295 if (dst_reg->u32_min_value + umin_val < umin_val ||
12296 dst_reg->u32_max_value + umax_val < umax_val) {
12297 dst_reg->u32_min_value = 0;
12298 dst_reg->u32_max_value = U32_MAX;
12300 dst_reg->u32_min_value += umin_val;
12301 dst_reg->u32_max_value += umax_val;
12305 static void scalar_min_max_add(struct bpf_reg_state *dst_reg,
12306 struct bpf_reg_state *src_reg)
12308 s64 smin_val = src_reg->smin_value;
12309 s64 smax_val = src_reg->smax_value;
12310 u64 umin_val = src_reg->umin_value;
12311 u64 umax_val = src_reg->umax_value;
12313 if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
12314 signed_add_overflows(dst_reg->smax_value, smax_val)) {
12315 dst_reg->smin_value = S64_MIN;
12316 dst_reg->smax_value = S64_MAX;
12318 dst_reg->smin_value += smin_val;
12319 dst_reg->smax_value += smax_val;
12321 if (dst_reg->umin_value + umin_val < umin_val ||
12322 dst_reg->umax_value + umax_val < umax_val) {
12323 dst_reg->umin_value = 0;
12324 dst_reg->umax_value = U64_MAX;
12326 dst_reg->umin_value += umin_val;
12327 dst_reg->umax_value += umax_val;
12331 static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg,
12332 struct bpf_reg_state *src_reg)
12334 s32 smin_val = src_reg->s32_min_value;
12335 s32 smax_val = src_reg->s32_max_value;
12336 u32 umin_val = src_reg->u32_min_value;
12337 u32 umax_val = src_reg->u32_max_value;
12339 if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) ||
12340 signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) {
12341 /* Overflow possible, we know nothing */
12342 dst_reg->s32_min_value = S32_MIN;
12343 dst_reg->s32_max_value = S32_MAX;
12345 dst_reg->s32_min_value -= smax_val;
12346 dst_reg->s32_max_value -= smin_val;
12348 if (dst_reg->u32_min_value < umax_val) {
12349 /* Overflow possible, we know nothing */
12350 dst_reg->u32_min_value = 0;
12351 dst_reg->u32_max_value = U32_MAX;
12353 /* Cannot overflow (as long as bounds are consistent) */
12354 dst_reg->u32_min_value -= umax_val;
12355 dst_reg->u32_max_value -= umin_val;
12359 static void scalar_min_max_sub(struct bpf_reg_state *dst_reg,
12360 struct bpf_reg_state *src_reg)
12362 s64 smin_val = src_reg->smin_value;
12363 s64 smax_val = src_reg->smax_value;
12364 u64 umin_val = src_reg->umin_value;
12365 u64 umax_val = src_reg->umax_value;
12367 if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
12368 signed_sub_overflows(dst_reg->smax_value, smin_val)) {
12369 /* Overflow possible, we know nothing */
12370 dst_reg->smin_value = S64_MIN;
12371 dst_reg->smax_value = S64_MAX;
12373 dst_reg->smin_value -= smax_val;
12374 dst_reg->smax_value -= smin_val;
12376 if (dst_reg->umin_value < umax_val) {
12377 /* Overflow possible, we know nothing */
12378 dst_reg->umin_value = 0;
12379 dst_reg->umax_value = U64_MAX;
12381 /* Cannot overflow (as long as bounds are consistent) */
12382 dst_reg->umin_value -= umax_val;
12383 dst_reg->umax_value -= umin_val;
12387 static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg,
12388 struct bpf_reg_state *src_reg)
12390 s32 smin_val = src_reg->s32_min_value;
12391 u32 umin_val = src_reg->u32_min_value;
12392 u32 umax_val = src_reg->u32_max_value;
12394 if (smin_val < 0 || dst_reg->s32_min_value < 0) {
12395 /* Ain't nobody got time to multiply that sign */
12396 __mark_reg32_unbounded(dst_reg);
12399 /* Both values are positive, so we can work with unsigned and
12400 * copy the result to signed (unless it exceeds S32_MAX).
12402 if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) {
12403 /* Potential overflow, we know nothing */
12404 __mark_reg32_unbounded(dst_reg);
12407 dst_reg->u32_min_value *= umin_val;
12408 dst_reg->u32_max_value *= umax_val;
12409 if (dst_reg->u32_max_value > S32_MAX) {
12410 /* Overflow possible, we know nothing */
12411 dst_reg->s32_min_value = S32_MIN;
12412 dst_reg->s32_max_value = S32_MAX;
12414 dst_reg->s32_min_value = dst_reg->u32_min_value;
12415 dst_reg->s32_max_value = dst_reg->u32_max_value;
12419 static void scalar_min_max_mul(struct bpf_reg_state *dst_reg,
12420 struct bpf_reg_state *src_reg)
12422 s64 smin_val = src_reg->smin_value;
12423 u64 umin_val = src_reg->umin_value;
12424 u64 umax_val = src_reg->umax_value;
12426 if (smin_val < 0 || dst_reg->smin_value < 0) {
12427 /* Ain't nobody got time to multiply that sign */
12428 __mark_reg64_unbounded(dst_reg);
12431 /* Both values are positive, so we can work with unsigned and
12432 * copy the result to signed (unless it exceeds S64_MAX).
12434 if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) {
12435 /* Potential overflow, we know nothing */
12436 __mark_reg64_unbounded(dst_reg);
12439 dst_reg->umin_value *= umin_val;
12440 dst_reg->umax_value *= umax_val;
12441 if (dst_reg->umax_value > S64_MAX) {
12442 /* Overflow possible, we know nothing */
12443 dst_reg->smin_value = S64_MIN;
12444 dst_reg->smax_value = S64_MAX;
12446 dst_reg->smin_value = dst_reg->umin_value;
12447 dst_reg->smax_value = dst_reg->umax_value;
12451 static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
12452 struct bpf_reg_state *src_reg)
12454 bool src_known = tnum_subreg_is_const(src_reg->var_off);
12455 bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
12456 struct tnum var32_off = tnum_subreg(dst_reg->var_off);
12457 s32 smin_val = src_reg->s32_min_value;
12458 u32 umax_val = src_reg->u32_max_value;
12460 if (src_known && dst_known) {
12461 __mark_reg32_known(dst_reg, var32_off.value);
12465 /* We get our minimum from the var_off, since that's inherently
12466 * bitwise. Our maximum is the minimum of the operands' maxima.
12468 dst_reg->u32_min_value = var32_off.value;
12469 dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val);
12470 if (dst_reg->s32_min_value < 0 || smin_val < 0) {
12471 /* Lose signed bounds when ANDing negative numbers,
12472 * ain't nobody got time for that.
12474 dst_reg->s32_min_value = S32_MIN;
12475 dst_reg->s32_max_value = S32_MAX;
12477 /* ANDing two positives gives a positive, so safe to
12478 * cast result into s64.
12480 dst_reg->s32_min_value = dst_reg->u32_min_value;
12481 dst_reg->s32_max_value = dst_reg->u32_max_value;
12485 static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
12486 struct bpf_reg_state *src_reg)
12488 bool src_known = tnum_is_const(src_reg->var_off);
12489 bool dst_known = tnum_is_const(dst_reg->var_off);
12490 s64 smin_val = src_reg->smin_value;
12491 u64 umax_val = src_reg->umax_value;
12493 if (src_known && dst_known) {
12494 __mark_reg_known(dst_reg, dst_reg->var_off.value);
12498 /* We get our minimum from the var_off, since that's inherently
12499 * bitwise. Our maximum is the minimum of the operands' maxima.
12501 dst_reg->umin_value = dst_reg->var_off.value;
12502 dst_reg->umax_value = min(dst_reg->umax_value, umax_val);
12503 if (dst_reg->smin_value < 0 || smin_val < 0) {
12504 /* Lose signed bounds when ANDing negative numbers,
12505 * ain't nobody got time for that.
12507 dst_reg->smin_value = S64_MIN;
12508 dst_reg->smax_value = S64_MAX;
12510 /* ANDing two positives gives a positive, so safe to
12511 * cast result into s64.
12513 dst_reg->smin_value = dst_reg->umin_value;
12514 dst_reg->smax_value = dst_reg->umax_value;
12516 /* We may learn something more from the var_off */
12517 __update_reg_bounds(dst_reg);
12520 static void scalar32_min_max_or(struct bpf_reg_state *dst_reg,
12521 struct bpf_reg_state *src_reg)
12523 bool src_known = tnum_subreg_is_const(src_reg->var_off);
12524 bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
12525 struct tnum var32_off = tnum_subreg(dst_reg->var_off);
12526 s32 smin_val = src_reg->s32_min_value;
12527 u32 umin_val = src_reg->u32_min_value;
12529 if (src_known && dst_known) {
12530 __mark_reg32_known(dst_reg, var32_off.value);
12534 /* We get our maximum from the var_off, and our minimum is the
12535 * maximum of the operands' minima
12537 dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val);
12538 dst_reg->u32_max_value = var32_off.value | var32_off.mask;
12539 if (dst_reg->s32_min_value < 0 || smin_val < 0) {
12540 /* Lose signed bounds when ORing negative numbers,
12541 * ain't nobody got time for that.
12543 dst_reg->s32_min_value = S32_MIN;
12544 dst_reg->s32_max_value = S32_MAX;
12546 /* ORing two positives gives a positive, so safe to
12547 * cast result into s64.
12549 dst_reg->s32_min_value = dst_reg->u32_min_value;
12550 dst_reg->s32_max_value = dst_reg->u32_max_value;
12554 static void scalar_min_max_or(struct bpf_reg_state *dst_reg,
12555 struct bpf_reg_state *src_reg)
12557 bool src_known = tnum_is_const(src_reg->var_off);
12558 bool dst_known = tnum_is_const(dst_reg->var_off);
12559 s64 smin_val = src_reg->smin_value;
12560 u64 umin_val = src_reg->umin_value;
12562 if (src_known && dst_known) {
12563 __mark_reg_known(dst_reg, dst_reg->var_off.value);
12567 /* We get our maximum from the var_off, and our minimum is the
12568 * maximum of the operands' minima
12570 dst_reg->umin_value = max(dst_reg->umin_value, umin_val);
12571 dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
12572 if (dst_reg->smin_value < 0 || smin_val < 0) {
12573 /* Lose signed bounds when ORing negative numbers,
12574 * ain't nobody got time for that.
12576 dst_reg->smin_value = S64_MIN;
12577 dst_reg->smax_value = S64_MAX;
12579 /* ORing two positives gives a positive, so safe to
12580 * cast result into s64.
12582 dst_reg->smin_value = dst_reg->umin_value;
12583 dst_reg->smax_value = dst_reg->umax_value;
12585 /* We may learn something more from the var_off */
12586 __update_reg_bounds(dst_reg);
12589 static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg,
12590 struct bpf_reg_state *src_reg)
12592 bool src_known = tnum_subreg_is_const(src_reg->var_off);
12593 bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
12594 struct tnum var32_off = tnum_subreg(dst_reg->var_off);
12595 s32 smin_val = src_reg->s32_min_value;
12597 if (src_known && dst_known) {
12598 __mark_reg32_known(dst_reg, var32_off.value);
12602 /* We get both minimum and maximum from the var32_off. */
12603 dst_reg->u32_min_value = var32_off.value;
12604 dst_reg->u32_max_value = var32_off.value | var32_off.mask;
12606 if (dst_reg->s32_min_value >= 0 && smin_val >= 0) {
12607 /* XORing two positive sign numbers gives a positive,
12608 * so safe to cast u32 result into s32.
12610 dst_reg->s32_min_value = dst_reg->u32_min_value;
12611 dst_reg->s32_max_value = dst_reg->u32_max_value;
12613 dst_reg->s32_min_value = S32_MIN;
12614 dst_reg->s32_max_value = S32_MAX;
12618 static void scalar_min_max_xor(struct bpf_reg_state *dst_reg,
12619 struct bpf_reg_state *src_reg)
12621 bool src_known = tnum_is_const(src_reg->var_off);
12622 bool dst_known = tnum_is_const(dst_reg->var_off);
12623 s64 smin_val = src_reg->smin_value;
12625 if (src_known && dst_known) {
12626 /* dst_reg->var_off.value has been updated earlier */
12627 __mark_reg_known(dst_reg, dst_reg->var_off.value);
12631 /* We get both minimum and maximum from the var_off. */
12632 dst_reg->umin_value = dst_reg->var_off.value;
12633 dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
12635 if (dst_reg->smin_value >= 0 && smin_val >= 0) {
12636 /* XORing two positive sign numbers gives a positive,
12637 * so safe to cast u64 result into s64.
12639 dst_reg->smin_value = dst_reg->umin_value;
12640 dst_reg->smax_value = dst_reg->umax_value;
12642 dst_reg->smin_value = S64_MIN;
12643 dst_reg->smax_value = S64_MAX;
12646 __update_reg_bounds(dst_reg);
12649 static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
12650 u64 umin_val, u64 umax_val)
12652 /* We lose all sign bit information (except what we can pick
12655 dst_reg->s32_min_value = S32_MIN;
12656 dst_reg->s32_max_value = S32_MAX;
12657 /* If we might shift our top bit out, then we know nothing */
12658 if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) {
12659 dst_reg->u32_min_value = 0;
12660 dst_reg->u32_max_value = U32_MAX;
12662 dst_reg->u32_min_value <<= umin_val;
12663 dst_reg->u32_max_value <<= umax_val;
12667 static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
12668 struct bpf_reg_state *src_reg)
12670 u32 umax_val = src_reg->u32_max_value;
12671 u32 umin_val = src_reg->u32_min_value;
12672 /* u32 alu operation will zext upper bits */
12673 struct tnum subreg = tnum_subreg(dst_reg->var_off);
12675 __scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
12676 dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val));
12677 /* Not required but being careful mark reg64 bounds as unknown so
12678 * that we are forced to pick them up from tnum and zext later and
12679 * if some path skips this step we are still safe.
12681 __mark_reg64_unbounded(dst_reg);
12682 __update_reg32_bounds(dst_reg);
12685 static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg,
12686 u64 umin_val, u64 umax_val)
12688 /* Special case <<32 because it is a common compiler pattern to sign
12689 * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
12690 * positive we know this shift will also be positive so we can track
12691 * bounds correctly. Otherwise we lose all sign bit information except
12692 * what we can pick up from var_off. Perhaps we can generalize this
12693 * later to shifts of any length.
12695 if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0)
12696 dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32;
12698 dst_reg->smax_value = S64_MAX;
12700 if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0)
12701 dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32;
12703 dst_reg->smin_value = S64_MIN;
12705 /* If we might shift our top bit out, then we know nothing */
12706 if (dst_reg->umax_value > 1ULL << (63 - umax_val)) {
12707 dst_reg->umin_value = 0;
12708 dst_reg->umax_value = U64_MAX;
12710 dst_reg->umin_value <<= umin_val;
12711 dst_reg->umax_value <<= umax_val;
12715 static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg,
12716 struct bpf_reg_state *src_reg)
12718 u64 umax_val = src_reg->umax_value;
12719 u64 umin_val = src_reg->umin_value;
12721 /* scalar64 calc uses 32bit unshifted bounds so must be called first */
12722 __scalar64_min_max_lsh(dst_reg, umin_val, umax_val);
12723 __scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
12725 dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
12726 /* We may learn something more from the var_off */
12727 __update_reg_bounds(dst_reg);
12730 static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg,
12731 struct bpf_reg_state *src_reg)
12733 struct tnum subreg = tnum_subreg(dst_reg->var_off);
12734 u32 umax_val = src_reg->u32_max_value;
12735 u32 umin_val = src_reg->u32_min_value;
12737 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
12738 * be negative, then either:
12739 * 1) src_reg might be zero, so the sign bit of the result is
12740 * unknown, so we lose our signed bounds
12741 * 2) it's known negative, thus the unsigned bounds capture the
12743 * 3) the signed bounds cross zero, so they tell us nothing
12745 * If the value in dst_reg is known nonnegative, then again the
12746 * unsigned bounds capture the signed bounds.
12747 * Thus, in all cases it suffices to blow away our signed bounds
12748 * and rely on inferring new ones from the unsigned bounds and
12749 * var_off of the result.
12751 dst_reg->s32_min_value = S32_MIN;
12752 dst_reg->s32_max_value = S32_MAX;
12754 dst_reg->var_off = tnum_rshift(subreg, umin_val);
12755 dst_reg->u32_min_value >>= umax_val;
12756 dst_reg->u32_max_value >>= umin_val;
12758 __mark_reg64_unbounded(dst_reg);
12759 __update_reg32_bounds(dst_reg);
12762 static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg,
12763 struct bpf_reg_state *src_reg)
12765 u64 umax_val = src_reg->umax_value;
12766 u64 umin_val = src_reg->umin_value;
12768 /* BPF_RSH is an unsigned shift. If the value in dst_reg might
12769 * be negative, then either:
12770 * 1) src_reg might be zero, so the sign bit of the result is
12771 * unknown, so we lose our signed bounds
12772 * 2) it's known negative, thus the unsigned bounds capture the
12774 * 3) the signed bounds cross zero, so they tell us nothing
12776 * If the value in dst_reg is known nonnegative, then again the
12777 * unsigned bounds capture the signed bounds.
12778 * Thus, in all cases it suffices to blow away our signed bounds
12779 * and rely on inferring new ones from the unsigned bounds and
12780 * var_off of the result.
12782 dst_reg->smin_value = S64_MIN;
12783 dst_reg->smax_value = S64_MAX;
12784 dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
12785 dst_reg->umin_value >>= umax_val;
12786 dst_reg->umax_value >>= umin_val;
12788 /* Its not easy to operate on alu32 bounds here because it depends
12789 * on bits being shifted in. Take easy way out and mark unbounded
12790 * so we can recalculate later from tnum.
12792 __mark_reg32_unbounded(dst_reg);
12793 __update_reg_bounds(dst_reg);
12796 static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg,
12797 struct bpf_reg_state *src_reg)
12799 u64 umin_val = src_reg->u32_min_value;
12801 /* Upon reaching here, src_known is true and
12802 * umax_val is equal to umin_val.
12804 dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val);
12805 dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val);
12807 dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32);
12809 /* blow away the dst_reg umin_value/umax_value and rely on
12810 * dst_reg var_off to refine the result.
12812 dst_reg->u32_min_value = 0;
12813 dst_reg->u32_max_value = U32_MAX;
12815 __mark_reg64_unbounded(dst_reg);
12816 __update_reg32_bounds(dst_reg);
12819 static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg,
12820 struct bpf_reg_state *src_reg)
12822 u64 umin_val = src_reg->umin_value;
12824 /* Upon reaching here, src_known is true and umax_val is equal
12827 dst_reg->smin_value >>= umin_val;
12828 dst_reg->smax_value >>= umin_val;
12830 dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64);
12832 /* blow away the dst_reg umin_value/umax_value and rely on
12833 * dst_reg var_off to refine the result.
12835 dst_reg->umin_value = 0;
12836 dst_reg->umax_value = U64_MAX;
12838 /* Its not easy to operate on alu32 bounds here because it depends
12839 * on bits being shifted in from upper 32-bits. Take easy way out
12840 * and mark unbounded so we can recalculate later from tnum.
12842 __mark_reg32_unbounded(dst_reg);
12843 __update_reg_bounds(dst_reg);
12846 /* WARNING: This function does calculations on 64-bit values, but the actual
12847 * execution may occur on 32-bit values. Therefore, things like bitshifts
12848 * need extra checks in the 32-bit case.
12850 static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
12851 struct bpf_insn *insn,
12852 struct bpf_reg_state *dst_reg,
12853 struct bpf_reg_state src_reg)
12855 struct bpf_reg_state *regs = cur_regs(env);
12856 u8 opcode = BPF_OP(insn->code);
12858 s64 smin_val, smax_val;
12859 u64 umin_val, umax_val;
12860 s32 s32_min_val, s32_max_val;
12861 u32 u32_min_val, u32_max_val;
12862 u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
12863 bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64);
12866 smin_val = src_reg.smin_value;
12867 smax_val = src_reg.smax_value;
12868 umin_val = src_reg.umin_value;
12869 umax_val = src_reg.umax_value;
12871 s32_min_val = src_reg.s32_min_value;
12872 s32_max_val = src_reg.s32_max_value;
12873 u32_min_val = src_reg.u32_min_value;
12874 u32_max_val = src_reg.u32_max_value;
12877 src_known = tnum_subreg_is_const(src_reg.var_off);
12879 (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
12880 s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
12881 /* Taint dst register if offset had invalid bounds
12882 * derived from e.g. dead branches.
12884 __mark_reg_unknown(env, dst_reg);
12888 src_known = tnum_is_const(src_reg.var_off);
12890 (smin_val != smax_val || umin_val != umax_val)) ||
12891 smin_val > smax_val || umin_val > umax_val) {
12892 /* Taint dst register if offset had invalid bounds
12893 * derived from e.g. dead branches.
12895 __mark_reg_unknown(env, dst_reg);
12901 opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
12902 __mark_reg_unknown(env, dst_reg);
12906 if (sanitize_needed(opcode)) {
12907 ret = sanitize_val_alu(env, insn);
12909 return sanitize_err(env, insn, ret, NULL, NULL);
12912 /* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
12913 * There are two classes of instructions: The first class we track both
12914 * alu32 and alu64 sign/unsigned bounds independently this provides the
12915 * greatest amount of precision when alu operations are mixed with jmp32
12916 * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
12917 * and BPF_OR. This is possible because these ops have fairly easy to
12918 * understand and calculate behavior in both 32-bit and 64-bit alu ops.
12919 * See alu32 verifier tests for examples. The second class of
12920 * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
12921 * with regards to tracking sign/unsigned bounds because the bits may
12922 * cross subreg boundaries in the alu64 case. When this happens we mark
12923 * the reg unbounded in the subreg bound space and use the resulting
12924 * tnum to calculate an approximation of the sign/unsigned bounds.
12928 scalar32_min_max_add(dst_reg, &src_reg);
12929 scalar_min_max_add(dst_reg, &src_reg);
12930 dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
12933 scalar32_min_max_sub(dst_reg, &src_reg);
12934 scalar_min_max_sub(dst_reg, &src_reg);
12935 dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off);
12938 dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off);
12939 scalar32_min_max_mul(dst_reg, &src_reg);
12940 scalar_min_max_mul(dst_reg, &src_reg);
12943 dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off);
12944 scalar32_min_max_and(dst_reg, &src_reg);
12945 scalar_min_max_and(dst_reg, &src_reg);
12948 dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off);
12949 scalar32_min_max_or(dst_reg, &src_reg);
12950 scalar_min_max_or(dst_reg, &src_reg);
12953 dst_reg->var_off = tnum_xor(dst_reg->var_off, src_reg.var_off);
12954 scalar32_min_max_xor(dst_reg, &src_reg);
12955 scalar_min_max_xor(dst_reg, &src_reg);
12958 if (umax_val >= insn_bitness) {
12959 /* Shifts greater than 31 or 63 are undefined.
12960 * This includes shifts by a negative number.
12962 mark_reg_unknown(env, regs, insn->dst_reg);
12966 scalar32_min_max_lsh(dst_reg, &src_reg);
12968 scalar_min_max_lsh(dst_reg, &src_reg);
12971 if (umax_val >= insn_bitness) {
12972 /* Shifts greater than 31 or 63 are undefined.
12973 * This includes shifts by a negative number.
12975 mark_reg_unknown(env, regs, insn->dst_reg);
12979 scalar32_min_max_rsh(dst_reg, &src_reg);
12981 scalar_min_max_rsh(dst_reg, &src_reg);
12984 if (umax_val >= insn_bitness) {
12985 /* Shifts greater than 31 or 63 are undefined.
12986 * This includes shifts by a negative number.
12988 mark_reg_unknown(env, regs, insn->dst_reg);
12992 scalar32_min_max_arsh(dst_reg, &src_reg);
12994 scalar_min_max_arsh(dst_reg, &src_reg);
12997 mark_reg_unknown(env, regs, insn->dst_reg);
13001 /* ALU32 ops are zero extended into 64bit register */
13003 zext_32_to_64(dst_reg);
13004 reg_bounds_sync(dst_reg);
13008 /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
13011 static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
13012 struct bpf_insn *insn)
13014 struct bpf_verifier_state *vstate = env->cur_state;
13015 struct bpf_func_state *state = vstate->frame[vstate->curframe];
13016 struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
13017 struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
13018 u8 opcode = BPF_OP(insn->code);
13021 dst_reg = ®s[insn->dst_reg];
13023 if (dst_reg->type != SCALAR_VALUE)
13026 /* Make sure ID is cleared otherwise dst_reg min/max could be
13027 * incorrectly propagated into other registers by find_equal_scalars()
13030 if (BPF_SRC(insn->code) == BPF_X) {
13031 src_reg = ®s[insn->src_reg];
13032 if (src_reg->type != SCALAR_VALUE) {
13033 if (dst_reg->type != SCALAR_VALUE) {
13034 /* Combining two pointers by any ALU op yields
13035 * an arbitrary scalar. Disallow all math except
13036 * pointer subtraction
13038 if (opcode == BPF_SUB && env->allow_ptr_leaks) {
13039 mark_reg_unknown(env, regs, insn->dst_reg);
13042 verbose(env, "R%d pointer %s pointer prohibited\n",
13044 bpf_alu_string[opcode >> 4]);
13047 /* scalar += pointer
13048 * This is legal, but we have to reverse our
13049 * src/dest handling in computing the range
13051 err = mark_chain_precision(env, insn->dst_reg);
13054 return adjust_ptr_min_max_vals(env, insn,
13057 } else if (ptr_reg) {
13058 /* pointer += scalar */
13059 err = mark_chain_precision(env, insn->src_reg);
13062 return adjust_ptr_min_max_vals(env, insn,
13064 } else if (dst_reg->precise) {
13065 /* if dst_reg is precise, src_reg should be precise as well */
13066 err = mark_chain_precision(env, insn->src_reg);
13071 /* Pretend the src is a reg with a known value, since we only
13072 * need to be able to read from this state.
13074 off_reg.type = SCALAR_VALUE;
13075 __mark_reg_known(&off_reg, insn->imm);
13076 src_reg = &off_reg;
13077 if (ptr_reg) /* pointer += K */
13078 return adjust_ptr_min_max_vals(env, insn,
13082 /* Got here implies adding two SCALAR_VALUEs */
13083 if (WARN_ON_ONCE(ptr_reg)) {
13084 print_verifier_state(env, state, true);
13085 verbose(env, "verifier internal error: unexpected ptr_reg\n");
13088 if (WARN_ON(!src_reg)) {
13089 print_verifier_state(env, state, true);
13090 verbose(env, "verifier internal error: no src_reg\n");
13093 return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg);
13096 /* check validity of 32-bit and 64-bit arithmetic operations */
13097 static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
13099 struct bpf_reg_state *regs = cur_regs(env);
13100 u8 opcode = BPF_OP(insn->code);
13103 if (opcode == BPF_END || opcode == BPF_NEG) {
13104 if (opcode == BPF_NEG) {
13105 if (BPF_SRC(insn->code) != BPF_K ||
13106 insn->src_reg != BPF_REG_0 ||
13107 insn->off != 0 || insn->imm != 0) {
13108 verbose(env, "BPF_NEG uses reserved fields\n");
13112 if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
13113 (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
13114 (BPF_CLASS(insn->code) == BPF_ALU64 &&
13115 BPF_SRC(insn->code) != BPF_TO_LE)) {
13116 verbose(env, "BPF_END uses reserved fields\n");
13121 /* check src operand */
13122 err = check_reg_arg(env, insn->dst_reg, SRC_OP);
13126 if (is_pointer_value(env, insn->dst_reg)) {
13127 verbose(env, "R%d pointer arithmetic prohibited\n",
13132 /* check dest operand */
13133 err = check_reg_arg(env, insn->dst_reg, DST_OP);
13137 } else if (opcode == BPF_MOV) {
13139 if (BPF_SRC(insn->code) == BPF_X) {
13140 if (insn->imm != 0) {
13141 verbose(env, "BPF_MOV uses reserved fields\n");
13145 if (BPF_CLASS(insn->code) == BPF_ALU) {
13146 if (insn->off != 0 && insn->off != 8 && insn->off != 16) {
13147 verbose(env, "BPF_MOV uses reserved fields\n");
13151 if (insn->off != 0 && insn->off != 8 && insn->off != 16 &&
13153 verbose(env, "BPF_MOV uses reserved fields\n");
13158 /* check src operand */
13159 err = check_reg_arg(env, insn->src_reg, SRC_OP);
13163 if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
13164 verbose(env, "BPF_MOV uses reserved fields\n");
13169 /* check dest operand, mark as required later */
13170 err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
13174 if (BPF_SRC(insn->code) == BPF_X) {
13175 struct bpf_reg_state *src_reg = regs + insn->src_reg;
13176 struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
13177 bool need_id = src_reg->type == SCALAR_VALUE && !src_reg->id &&
13178 !tnum_is_const(src_reg->var_off);
13180 if (BPF_CLASS(insn->code) == BPF_ALU64) {
13181 if (insn->off == 0) {
13183 * copy register state to dest reg
13186 /* Assign src and dst registers the same ID
13187 * that will be used by find_equal_scalars()
13188 * to propagate min/max range.
13190 src_reg->id = ++env->id_gen;
13191 copy_register_state(dst_reg, src_reg);
13192 dst_reg->live |= REG_LIVE_WRITTEN;
13193 dst_reg->subreg_def = DEF_NOT_SUBREG;
13195 /* case: R1 = (s8, s16 s32)R2 */
13196 if (is_pointer_value(env, insn->src_reg)) {
13198 "R%d sign-extension part of pointer\n",
13201 } else if (src_reg->type == SCALAR_VALUE) {
13204 no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
13205 if (no_sext && need_id)
13206 src_reg->id = ++env->id_gen;
13207 copy_register_state(dst_reg, src_reg);
13210 coerce_reg_to_size_sx(dst_reg, insn->off >> 3);
13211 dst_reg->live |= REG_LIVE_WRITTEN;
13212 dst_reg->subreg_def = DEF_NOT_SUBREG;
13214 mark_reg_unknown(env, regs, insn->dst_reg);
13218 /* R1 = (u32) R2 */
13219 if (is_pointer_value(env, insn->src_reg)) {
13221 "R%d partial copy of pointer\n",
13224 } else if (src_reg->type == SCALAR_VALUE) {
13225 if (insn->off == 0) {
13226 bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
13228 if (is_src_reg_u32 && need_id)
13229 src_reg->id = ++env->id_gen;
13230 copy_register_state(dst_reg, src_reg);
13231 /* Make sure ID is cleared if src_reg is not in u32
13232 * range otherwise dst_reg min/max could be incorrectly
13233 * propagated into src_reg by find_equal_scalars()
13235 if (!is_src_reg_u32)
13237 dst_reg->live |= REG_LIVE_WRITTEN;
13238 dst_reg->subreg_def = env->insn_idx + 1;
13240 /* case: W1 = (s8, s16)W2 */
13241 bool no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
13243 if (no_sext && need_id)
13244 src_reg->id = ++env->id_gen;
13245 copy_register_state(dst_reg, src_reg);
13248 dst_reg->live |= REG_LIVE_WRITTEN;
13249 dst_reg->subreg_def = env->insn_idx + 1;
13250 coerce_subreg_to_size_sx(dst_reg, insn->off >> 3);
13253 mark_reg_unknown(env, regs,
13256 zext_32_to_64(dst_reg);
13257 reg_bounds_sync(dst_reg);
13261 * remember the value we stored into this reg
13263 /* clear any state __mark_reg_known doesn't set */
13264 mark_reg_unknown(env, regs, insn->dst_reg);
13265 regs[insn->dst_reg].type = SCALAR_VALUE;
13266 if (BPF_CLASS(insn->code) == BPF_ALU64) {
13267 __mark_reg_known(regs + insn->dst_reg,
13270 __mark_reg_known(regs + insn->dst_reg,
13275 } else if (opcode > BPF_END) {
13276 verbose(env, "invalid BPF_ALU opcode %x\n", opcode);
13279 } else { /* all other ALU ops: and, sub, xor, add, ... */
13281 if (BPF_SRC(insn->code) == BPF_X) {
13282 if (insn->imm != 0 || insn->off > 1 ||
13283 (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) {
13284 verbose(env, "BPF_ALU uses reserved fields\n");
13287 /* check src1 operand */
13288 err = check_reg_arg(env, insn->src_reg, SRC_OP);
13292 if (insn->src_reg != BPF_REG_0 || insn->off > 1 ||
13293 (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) {
13294 verbose(env, "BPF_ALU uses reserved fields\n");
13299 /* check src2 operand */
13300 err = check_reg_arg(env, insn->dst_reg, SRC_OP);
13304 if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
13305 BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
13306 verbose(env, "div by zero\n");
13310 if ((opcode == BPF_LSH || opcode == BPF_RSH ||
13311 opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
13312 int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
13314 if (insn->imm < 0 || insn->imm >= size) {
13315 verbose(env, "invalid shift %d\n", insn->imm);
13320 /* check dest operand */
13321 err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
13325 return adjust_reg_min_max_vals(env, insn);
13331 static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
13332 struct bpf_reg_state *dst_reg,
13333 enum bpf_reg_type type,
13334 bool range_right_open)
13336 struct bpf_func_state *state;
13337 struct bpf_reg_state *reg;
13340 if (dst_reg->off < 0 ||
13341 (dst_reg->off == 0 && range_right_open))
13342 /* This doesn't give us any range */
13345 if (dst_reg->umax_value > MAX_PACKET_OFF ||
13346 dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
13347 /* Risk of overflow. For instance, ptr + (1<<63) may be less
13348 * than pkt_end, but that's because it's also less than pkt.
13352 new_range = dst_reg->off;
13353 if (range_right_open)
13356 /* Examples for register markings:
13358 * pkt_data in dst register:
13362 * if (r2 > pkt_end) goto <handle exception>
13367 * if (r2 < pkt_end) goto <access okay>
13368 * <handle exception>
13371 * r2 == dst_reg, pkt_end == src_reg
13372 * r2=pkt(id=n,off=8,r=0)
13373 * r3=pkt(id=n,off=0,r=0)
13375 * pkt_data in src register:
13379 * if (pkt_end >= r2) goto <access okay>
13380 * <handle exception>
13384 * if (pkt_end <= r2) goto <handle exception>
13388 * pkt_end == dst_reg, r2 == src_reg
13389 * r2=pkt(id=n,off=8,r=0)
13390 * r3=pkt(id=n,off=0,r=0)
13392 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
13393 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
13394 * and [r3, r3 + 8-1) respectively is safe to access depending on
13398 /* If our ids match, then we must have the same max_value. And we
13399 * don't care about the other reg's fixed offset, since if it's too big
13400 * the range won't allow anything.
13401 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
13403 bpf_for_each_reg_in_vstate(vstate, state, reg, ({
13404 if (reg->type == type && reg->id == dst_reg->id)
13405 /* keep the maximum range already checked */
13406 reg->range = max(reg->range, new_range);
13410 static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode)
13412 struct tnum subreg = tnum_subreg(reg->var_off);
13413 s32 sval = (s32)val;
13417 if (tnum_is_const(subreg))
13418 return !!tnum_equals_const(subreg, val);
13419 else if (val < reg->u32_min_value || val > reg->u32_max_value)
13423 if (tnum_is_const(subreg))
13424 return !tnum_equals_const(subreg, val);
13425 else if (val < reg->u32_min_value || val > reg->u32_max_value)
13429 if ((~subreg.mask & subreg.value) & val)
13431 if (!((subreg.mask | subreg.value) & val))
13435 if (reg->u32_min_value > val)
13437 else if (reg->u32_max_value <= val)
13441 if (reg->s32_min_value > sval)
13443 else if (reg->s32_max_value <= sval)
13447 if (reg->u32_max_value < val)
13449 else if (reg->u32_min_value >= val)
13453 if (reg->s32_max_value < sval)
13455 else if (reg->s32_min_value >= sval)
13459 if (reg->u32_min_value >= val)
13461 else if (reg->u32_max_value < val)
13465 if (reg->s32_min_value >= sval)
13467 else if (reg->s32_max_value < sval)
13471 if (reg->u32_max_value <= val)
13473 else if (reg->u32_min_value > val)
13477 if (reg->s32_max_value <= sval)
13479 else if (reg->s32_min_value > sval)
13488 static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
13490 s64 sval = (s64)val;
13494 if (tnum_is_const(reg->var_off))
13495 return !!tnum_equals_const(reg->var_off, val);
13496 else if (val < reg->umin_value || val > reg->umax_value)
13500 if (tnum_is_const(reg->var_off))
13501 return !tnum_equals_const(reg->var_off, val);
13502 else if (val < reg->umin_value || val > reg->umax_value)
13506 if ((~reg->var_off.mask & reg->var_off.value) & val)
13508 if (!((reg->var_off.mask | reg->var_off.value) & val))
13512 if (reg->umin_value > val)
13514 else if (reg->umax_value <= val)
13518 if (reg->smin_value > sval)
13520 else if (reg->smax_value <= sval)
13524 if (reg->umax_value < val)
13526 else if (reg->umin_value >= val)
13530 if (reg->smax_value < sval)
13532 else if (reg->smin_value >= sval)
13536 if (reg->umin_value >= val)
13538 else if (reg->umax_value < val)
13542 if (reg->smin_value >= sval)
13544 else if (reg->smax_value < sval)
13548 if (reg->umax_value <= val)
13550 else if (reg->umin_value > val)
13554 if (reg->smax_value <= sval)
13556 else if (reg->smin_value > sval)
13564 /* compute branch direction of the expression "if (reg opcode val) goto target;"
13566 * 1 - branch will be taken and "goto target" will be executed
13567 * 0 - branch will not be taken and fall-through to next insn
13568 * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
13571 static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
13574 if (__is_pointer_value(false, reg)) {
13575 if (!reg_not_null(reg))
13578 /* If pointer is valid tests against zero will fail so we can
13579 * use this to direct branch taken.
13595 return is_branch32_taken(reg, val, opcode);
13596 return is_branch64_taken(reg, val, opcode);
13599 static int flip_opcode(u32 opcode)
13601 /* How can we transform "a <op> b" into "b <op> a"? */
13602 static const u8 opcode_flip[16] = {
13603 /* these stay the same */
13604 [BPF_JEQ >> 4] = BPF_JEQ,
13605 [BPF_JNE >> 4] = BPF_JNE,
13606 [BPF_JSET >> 4] = BPF_JSET,
13607 /* these swap "lesser" and "greater" (L and G in the opcodes) */
13608 [BPF_JGE >> 4] = BPF_JLE,
13609 [BPF_JGT >> 4] = BPF_JLT,
13610 [BPF_JLE >> 4] = BPF_JGE,
13611 [BPF_JLT >> 4] = BPF_JGT,
13612 [BPF_JSGE >> 4] = BPF_JSLE,
13613 [BPF_JSGT >> 4] = BPF_JSLT,
13614 [BPF_JSLE >> 4] = BPF_JSGE,
13615 [BPF_JSLT >> 4] = BPF_JSGT
13617 return opcode_flip[opcode >> 4];
13620 static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg,
13621 struct bpf_reg_state *src_reg,
13624 struct bpf_reg_state *pkt;
13626 if (src_reg->type == PTR_TO_PACKET_END) {
13628 } else if (dst_reg->type == PTR_TO_PACKET_END) {
13630 opcode = flip_opcode(opcode);
13635 if (pkt->range >= 0)
13640 /* pkt <= pkt_end */
13643 /* pkt > pkt_end */
13644 if (pkt->range == BEYOND_PKT_END)
13645 /* pkt has at last one extra byte beyond pkt_end */
13646 return opcode == BPF_JGT;
13649 /* pkt < pkt_end */
13652 /* pkt >= pkt_end */
13653 if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END)
13654 return opcode == BPF_JGE;
13660 /* Adjusts the register min/max values in the case that the dst_reg is the
13661 * variable register that we are working on, and src_reg is a constant or we're
13662 * simply doing a BPF_K check.
13663 * In JEQ/JNE cases we also adjust the var_off values.
13665 static void reg_set_min_max(struct bpf_reg_state *true_reg,
13666 struct bpf_reg_state *false_reg,
13667 u64 val, u32 val32,
13668 u8 opcode, bool is_jmp32)
13670 struct tnum false_32off = tnum_subreg(false_reg->var_off);
13671 struct tnum false_64off = false_reg->var_off;
13672 struct tnum true_32off = tnum_subreg(true_reg->var_off);
13673 struct tnum true_64off = true_reg->var_off;
13674 s64 sval = (s64)val;
13675 s32 sval32 = (s32)val32;
13677 /* If the dst_reg is a pointer, we can't learn anything about its
13678 * variable offset from the compare (unless src_reg were a pointer into
13679 * the same object, but we don't bother with that.
13680 * Since false_reg and true_reg have the same type by construction, we
13681 * only need to check one of them for pointerness.
13683 if (__is_pointer_value(false, false_reg))
13687 /* JEQ/JNE comparison doesn't change the register equivalence.
13690 * if (r1 == 42) goto label;
13692 * label: // here both r1 and r2 are known to be 42.
13694 * Hence when marking register as known preserve it's ID.
13698 __mark_reg32_known(true_reg, val32);
13699 true_32off = tnum_subreg(true_reg->var_off);
13701 ___mark_reg_known(true_reg, val);
13702 true_64off = true_reg->var_off;
13707 __mark_reg32_known(false_reg, val32);
13708 false_32off = tnum_subreg(false_reg->var_off);
13710 ___mark_reg_known(false_reg, val);
13711 false_64off = false_reg->var_off;
13716 false_32off = tnum_and(false_32off, tnum_const(~val32));
13717 if (is_power_of_2(val32))
13718 true_32off = tnum_or(true_32off,
13719 tnum_const(val32));
13721 false_64off = tnum_and(false_64off, tnum_const(~val));
13722 if (is_power_of_2(val))
13723 true_64off = tnum_or(true_64off,
13731 u32 false_umax = opcode == BPF_JGT ? val32 : val32 - 1;
13732 u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32;
13734 false_reg->u32_max_value = min(false_reg->u32_max_value,
13736 true_reg->u32_min_value = max(true_reg->u32_min_value,
13739 u64 false_umax = opcode == BPF_JGT ? val : val - 1;
13740 u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
13742 false_reg->umax_value = min(false_reg->umax_value, false_umax);
13743 true_reg->umin_value = max(true_reg->umin_value, true_umin);
13751 s32 false_smax = opcode == BPF_JSGT ? sval32 : sval32 - 1;
13752 s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;
13754 false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
13755 true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
13757 s64 false_smax = opcode == BPF_JSGT ? sval : sval - 1;
13758 s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
13760 false_reg->smax_value = min(false_reg->smax_value, false_smax);
13761 true_reg->smin_value = max(true_reg->smin_value, true_smin);
13769 u32 false_umin = opcode == BPF_JLT ? val32 : val32 + 1;
13770 u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32;
13772 false_reg->u32_min_value = max(false_reg->u32_min_value,
13774 true_reg->u32_max_value = min(true_reg->u32_max_value,
13777 u64 false_umin = opcode == BPF_JLT ? val : val + 1;
13778 u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
13780 false_reg->umin_value = max(false_reg->umin_value, false_umin);
13781 true_reg->umax_value = min(true_reg->umax_value, true_umax);
13789 s32 false_smin = opcode == BPF_JSLT ? sval32 : sval32 + 1;
13790 s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;
13792 false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
13793 true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
13795 s64 false_smin = opcode == BPF_JSLT ? sval : sval + 1;
13796 s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
13798 false_reg->smin_value = max(false_reg->smin_value, false_smin);
13799 true_reg->smax_value = min(true_reg->smax_value, true_smax);
13808 false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
13809 tnum_subreg(false_32off));
13810 true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
13811 tnum_subreg(true_32off));
13812 __reg_combine_32_into_64(false_reg);
13813 __reg_combine_32_into_64(true_reg);
13815 false_reg->var_off = false_64off;
13816 true_reg->var_off = true_64off;
13817 __reg_combine_64_into_32(false_reg);
13818 __reg_combine_64_into_32(true_reg);
13822 /* Same as above, but for the case that dst_reg holds a constant and src_reg is
13823 * the variable reg.
13825 static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
13826 struct bpf_reg_state *false_reg,
13827 u64 val, u32 val32,
13828 u8 opcode, bool is_jmp32)
13830 opcode = flip_opcode(opcode);
13831 /* This uses zero as "not present in table"; luckily the zero opcode,
13832 * BPF_JA, can't get here.
13835 reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32);
13838 /* Regs are known to be equal, so intersect their min/max/var_off */
13839 static void __reg_combine_min_max(struct bpf_reg_state *src_reg,
13840 struct bpf_reg_state *dst_reg)
13842 src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value,
13843 dst_reg->umin_value);
13844 src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value,
13845 dst_reg->umax_value);
13846 src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value,
13847 dst_reg->smin_value);
13848 src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value,
13849 dst_reg->smax_value);
13850 src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off,
13852 reg_bounds_sync(src_reg);
13853 reg_bounds_sync(dst_reg);
13856 static void reg_combine_min_max(struct bpf_reg_state *true_src,
13857 struct bpf_reg_state *true_dst,
13858 struct bpf_reg_state *false_src,
13859 struct bpf_reg_state *false_dst,
13864 __reg_combine_min_max(true_src, true_dst);
13867 __reg_combine_min_max(false_src, false_dst);
13872 static void mark_ptr_or_null_reg(struct bpf_func_state *state,
13873 struct bpf_reg_state *reg, u32 id,
13876 if (type_may_be_null(reg->type) && reg->id == id &&
13877 (is_rcu_reg(reg) || !WARN_ON_ONCE(!reg->id))) {
13878 /* Old offset (both fixed and variable parts) should have been
13879 * known-zero, because we don't allow pointer arithmetic on
13880 * pointers that might be NULL. If we see this happening, don't
13881 * convert the register.
13883 * But in some cases, some helpers that return local kptrs
13884 * advance offset for the returned pointer. In those cases, it
13885 * is fine to expect to see reg->off.
13887 if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
13889 if (!(type_is_ptr_alloc_obj(reg->type) || type_is_non_owning_ref(reg->type)) &&
13890 WARN_ON_ONCE(reg->off))
13894 reg->type = SCALAR_VALUE;
13895 /* We don't need id and ref_obj_id from this point
13896 * onwards anymore, thus we should better reset it,
13897 * so that state pruning has chances to take effect.
13900 reg->ref_obj_id = 0;
13905 mark_ptr_not_null_reg(reg);
13907 if (!reg_may_point_to_spin_lock(reg)) {
13908 /* For not-NULL ptr, reg->ref_obj_id will be reset
13909 * in release_reference().
13911 * reg->id is still used by spin_lock ptr. Other
13912 * than spin_lock ptr type, reg->id can be reset.
13919 /* The logic is similar to find_good_pkt_pointers(), both could eventually
13920 * be folded together at some point.
13922 static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
13925 struct bpf_func_state *state = vstate->frame[vstate->curframe];
13926 struct bpf_reg_state *regs = state->regs, *reg;
13927 u32 ref_obj_id = regs[regno].ref_obj_id;
13928 u32 id = regs[regno].id;
13930 if (ref_obj_id && ref_obj_id == id && is_null)
13931 /* regs[regno] is in the " == NULL" branch.
13932 * No one could have freed the reference state before
13933 * doing the NULL check.
13935 WARN_ON_ONCE(release_reference_state(state, id));
13937 bpf_for_each_reg_in_vstate(vstate, state, reg, ({
13938 mark_ptr_or_null_reg(state, reg, id, is_null);
13942 static bool try_match_pkt_pointers(const struct bpf_insn *insn,
13943 struct bpf_reg_state *dst_reg,
13944 struct bpf_reg_state *src_reg,
13945 struct bpf_verifier_state *this_branch,
13946 struct bpf_verifier_state *other_branch)
13948 if (BPF_SRC(insn->code) != BPF_X)
13951 /* Pointers are always 64-bit. */
13952 if (BPF_CLASS(insn->code) == BPF_JMP32)
13955 switch (BPF_OP(insn->code)) {
13957 if ((dst_reg->type == PTR_TO_PACKET &&
13958 src_reg->type == PTR_TO_PACKET_END) ||
13959 (dst_reg->type == PTR_TO_PACKET_META &&
13960 reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
13961 /* pkt_data' > pkt_end, pkt_meta' > pkt_data */
13962 find_good_pkt_pointers(this_branch, dst_reg,
13963 dst_reg->type, false);
13964 mark_pkt_end(other_branch, insn->dst_reg, true);
13965 } else if ((dst_reg->type == PTR_TO_PACKET_END &&
13966 src_reg->type == PTR_TO_PACKET) ||
13967 (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
13968 src_reg->type == PTR_TO_PACKET_META)) {
13969 /* pkt_end > pkt_data', pkt_data > pkt_meta' */
13970 find_good_pkt_pointers(other_branch, src_reg,
13971 src_reg->type, true);
13972 mark_pkt_end(this_branch, insn->src_reg, false);
13978 if ((dst_reg->type == PTR_TO_PACKET &&
13979 src_reg->type == PTR_TO_PACKET_END) ||
13980 (dst_reg->type == PTR_TO_PACKET_META &&
13981 reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
13982 /* pkt_data' < pkt_end, pkt_meta' < pkt_data */
13983 find_good_pkt_pointers(other_branch, dst_reg,
13984 dst_reg->type, true);
13985 mark_pkt_end(this_branch, insn->dst_reg, false);
13986 } else if ((dst_reg->type == PTR_TO_PACKET_END &&
13987 src_reg->type == PTR_TO_PACKET) ||
13988 (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
13989 src_reg->type == PTR_TO_PACKET_META)) {
13990 /* pkt_end < pkt_data', pkt_data > pkt_meta' */
13991 find_good_pkt_pointers(this_branch, src_reg,
13992 src_reg->type, false);
13993 mark_pkt_end(other_branch, insn->src_reg, true);
13999 if ((dst_reg->type == PTR_TO_PACKET &&
14000 src_reg->type == PTR_TO_PACKET_END) ||
14001 (dst_reg->type == PTR_TO_PACKET_META &&
14002 reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
14003 /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
14004 find_good_pkt_pointers(this_branch, dst_reg,
14005 dst_reg->type, true);
14006 mark_pkt_end(other_branch, insn->dst_reg, false);
14007 } else if ((dst_reg->type == PTR_TO_PACKET_END &&
14008 src_reg->type == PTR_TO_PACKET) ||
14009 (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
14010 src_reg->type == PTR_TO_PACKET_META)) {
14011 /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
14012 find_good_pkt_pointers(other_branch, src_reg,
14013 src_reg->type, false);
14014 mark_pkt_end(this_branch, insn->src_reg, true);
14020 if ((dst_reg->type == PTR_TO_PACKET &&
14021 src_reg->type == PTR_TO_PACKET_END) ||
14022 (dst_reg->type == PTR_TO_PACKET_META &&
14023 reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
14024 /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
14025 find_good_pkt_pointers(other_branch, dst_reg,
14026 dst_reg->type, false);
14027 mark_pkt_end(this_branch, insn->dst_reg, true);
14028 } else if ((dst_reg->type == PTR_TO_PACKET_END &&
14029 src_reg->type == PTR_TO_PACKET) ||
14030 (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
14031 src_reg->type == PTR_TO_PACKET_META)) {
14032 /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
14033 find_good_pkt_pointers(this_branch, src_reg,
14034 src_reg->type, true);
14035 mark_pkt_end(other_branch, insn->src_reg, false);
14047 static void find_equal_scalars(struct bpf_verifier_state *vstate,
14048 struct bpf_reg_state *known_reg)
14050 struct bpf_func_state *state;
14051 struct bpf_reg_state *reg;
14053 bpf_for_each_reg_in_vstate(vstate, state, reg, ({
14054 if (reg->type == SCALAR_VALUE && reg->id == known_reg->id)
14055 copy_register_state(reg, known_reg);
14059 static int check_cond_jmp_op(struct bpf_verifier_env *env,
14060 struct bpf_insn *insn, int *insn_idx)
14062 struct bpf_verifier_state *this_branch = env->cur_state;
14063 struct bpf_verifier_state *other_branch;
14064 struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
14065 struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
14066 struct bpf_reg_state *eq_branch_regs;
14067 u8 opcode = BPF_OP(insn->code);
14072 /* Only conditional jumps are expected to reach here. */
14073 if (opcode == BPF_JA || opcode > BPF_JSLE) {
14074 verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
14078 /* check src2 operand */
14079 err = check_reg_arg(env, insn->dst_reg, SRC_OP);
14083 dst_reg = ®s[insn->dst_reg];
14084 if (BPF_SRC(insn->code) == BPF_X) {
14085 if (insn->imm != 0) {
14086 verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
14090 /* check src1 operand */
14091 err = check_reg_arg(env, insn->src_reg, SRC_OP);
14095 src_reg = ®s[insn->src_reg];
14096 if (!(reg_is_pkt_pointer_any(dst_reg) && reg_is_pkt_pointer_any(src_reg)) &&
14097 is_pointer_value(env, insn->src_reg)) {
14098 verbose(env, "R%d pointer comparison prohibited\n",
14103 if (insn->src_reg != BPF_REG_0) {
14104 verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
14109 is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
14111 if (BPF_SRC(insn->code) == BPF_K) {
14112 pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32);
14113 } else if (src_reg->type == SCALAR_VALUE &&
14114 is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) {
14115 pred = is_branch_taken(dst_reg,
14116 tnum_subreg(src_reg->var_off).value,
14119 } else if (src_reg->type == SCALAR_VALUE &&
14120 !is_jmp32 && tnum_is_const(src_reg->var_off)) {
14121 pred = is_branch_taken(dst_reg,
14122 src_reg->var_off.value,
14125 } else if (dst_reg->type == SCALAR_VALUE &&
14126 is_jmp32 && tnum_is_const(tnum_subreg(dst_reg->var_off))) {
14127 pred = is_branch_taken(src_reg,
14128 tnum_subreg(dst_reg->var_off).value,
14129 flip_opcode(opcode),
14131 } else if (dst_reg->type == SCALAR_VALUE &&
14132 !is_jmp32 && tnum_is_const(dst_reg->var_off)) {
14133 pred = is_branch_taken(src_reg,
14134 dst_reg->var_off.value,
14135 flip_opcode(opcode),
14137 } else if (reg_is_pkt_pointer_any(dst_reg) &&
14138 reg_is_pkt_pointer_any(src_reg) &&
14140 pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode);
14144 /* If we get here with a dst_reg pointer type it is because
14145 * above is_branch_taken() special cased the 0 comparison.
14147 if (!__is_pointer_value(false, dst_reg))
14148 err = mark_chain_precision(env, insn->dst_reg);
14149 if (BPF_SRC(insn->code) == BPF_X && !err &&
14150 !__is_pointer_value(false, src_reg))
14151 err = mark_chain_precision(env, insn->src_reg);
14157 /* Only follow the goto, ignore fall-through. If needed, push
14158 * the fall-through branch for simulation under speculative
14161 if (!env->bypass_spec_v1 &&
14162 !sanitize_speculative_path(env, insn, *insn_idx + 1,
14165 if (env->log.level & BPF_LOG_LEVEL)
14166 print_insn_state(env, this_branch->frame[this_branch->curframe]);
14167 *insn_idx += insn->off;
14169 } else if (pred == 0) {
14170 /* Only follow the fall-through branch, since that's where the
14171 * program will go. If needed, push the goto branch for
14172 * simulation under speculative execution.
14174 if (!env->bypass_spec_v1 &&
14175 !sanitize_speculative_path(env, insn,
14176 *insn_idx + insn->off + 1,
14179 if (env->log.level & BPF_LOG_LEVEL)
14180 print_insn_state(env, this_branch->frame[this_branch->curframe]);
14184 other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
14188 other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
14190 /* detect if we are comparing against a constant value so we can adjust
14191 * our min/max values for our dst register.
14192 * this is only legit if both are scalars (or pointers to the same
14193 * object, I suppose, see the PTR_MAYBE_NULL related if block below),
14194 * because otherwise the different base pointers mean the offsets aren't
14197 if (BPF_SRC(insn->code) == BPF_X) {
14198 struct bpf_reg_state *src_reg = ®s[insn->src_reg];
14200 if (dst_reg->type == SCALAR_VALUE &&
14201 src_reg->type == SCALAR_VALUE) {
14202 if (tnum_is_const(src_reg->var_off) ||
14204 tnum_is_const(tnum_subreg(src_reg->var_off))))
14205 reg_set_min_max(&other_branch_regs[insn->dst_reg],
14207 src_reg->var_off.value,
14208 tnum_subreg(src_reg->var_off).value,
14210 else if (tnum_is_const(dst_reg->var_off) ||
14212 tnum_is_const(tnum_subreg(dst_reg->var_off))))
14213 reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
14215 dst_reg->var_off.value,
14216 tnum_subreg(dst_reg->var_off).value,
14218 else if (!is_jmp32 &&
14219 (opcode == BPF_JEQ || opcode == BPF_JNE))
14220 /* Comparing for equality, we can combine knowledge */
14221 reg_combine_min_max(&other_branch_regs[insn->src_reg],
14222 &other_branch_regs[insn->dst_reg],
14223 src_reg, dst_reg, opcode);
14225 !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) {
14226 find_equal_scalars(this_branch, src_reg);
14227 find_equal_scalars(other_branch, &other_branch_regs[insn->src_reg]);
14231 } else if (dst_reg->type == SCALAR_VALUE) {
14232 reg_set_min_max(&other_branch_regs[insn->dst_reg],
14233 dst_reg, insn->imm, (u32)insn->imm,
14237 if (dst_reg->type == SCALAR_VALUE && dst_reg->id &&
14238 !WARN_ON_ONCE(dst_reg->id != other_branch_regs[insn->dst_reg].id)) {
14239 find_equal_scalars(this_branch, dst_reg);
14240 find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]);
14243 /* if one pointer register is compared to another pointer
14244 * register check if PTR_MAYBE_NULL could be lifted.
14245 * E.g. register A - maybe null
14246 * register B - not null
14247 * for JNE A, B, ... - A is not null in the false branch;
14248 * for JEQ A, B, ... - A is not null in the true branch.
14250 * Since PTR_TO_BTF_ID points to a kernel struct that does
14251 * not need to be null checked by the BPF program, i.e.,
14252 * could be null even without PTR_MAYBE_NULL marking, so
14253 * only propagate nullness when neither reg is that type.
14255 if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X &&
14256 __is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) &&
14257 type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type) &&
14258 base_type(src_reg->type) != PTR_TO_BTF_ID &&
14259 base_type(dst_reg->type) != PTR_TO_BTF_ID) {
14260 eq_branch_regs = NULL;
14263 eq_branch_regs = other_branch_regs;
14266 eq_branch_regs = regs;
14272 if (eq_branch_regs) {
14273 if (type_may_be_null(src_reg->type))
14274 mark_ptr_not_null_reg(&eq_branch_regs[insn->src_reg]);
14276 mark_ptr_not_null_reg(&eq_branch_regs[insn->dst_reg]);
14280 /* detect if R == 0 where R is returned from bpf_map_lookup_elem().
14281 * NOTE: these optimizations below are related with pointer comparison
14282 * which will never be JMP32.
14284 if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
14285 insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
14286 type_may_be_null(dst_reg->type)) {
14287 /* Mark all identical registers in each branch as either
14288 * safe or unknown depending R == 0 or R != 0 conditional.
14290 mark_ptr_or_null_regs(this_branch, insn->dst_reg,
14291 opcode == BPF_JNE);
14292 mark_ptr_or_null_regs(other_branch, insn->dst_reg,
14293 opcode == BPF_JEQ);
14294 } else if (!try_match_pkt_pointers(insn, dst_reg, ®s[insn->src_reg],
14295 this_branch, other_branch) &&
14296 is_pointer_value(env, insn->dst_reg)) {
14297 verbose(env, "R%d pointer comparison prohibited\n",
14301 if (env->log.level & BPF_LOG_LEVEL)
14302 print_insn_state(env, this_branch->frame[this_branch->curframe]);
14306 /* verify BPF_LD_IMM64 instruction */
14307 static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
14309 struct bpf_insn_aux_data *aux = cur_aux(env);
14310 struct bpf_reg_state *regs = cur_regs(env);
14311 struct bpf_reg_state *dst_reg;
14312 struct bpf_map *map;
14315 if (BPF_SIZE(insn->code) != BPF_DW) {
14316 verbose(env, "invalid BPF_LD_IMM insn\n");
14319 if (insn->off != 0) {
14320 verbose(env, "BPF_LD_IMM64 uses reserved fields\n");
14324 err = check_reg_arg(env, insn->dst_reg, DST_OP);
14328 dst_reg = ®s[insn->dst_reg];
14329 if (insn->src_reg == 0) {
14330 u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
14332 dst_reg->type = SCALAR_VALUE;
14333 __mark_reg_known(®s[insn->dst_reg], imm);
14337 /* All special src_reg cases are listed below. From this point onwards
14338 * we either succeed and assign a corresponding dst_reg->type after
14339 * zeroing the offset, or fail and reject the program.
14341 mark_reg_known_zero(env, regs, insn->dst_reg);
14343 if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
14344 dst_reg->type = aux->btf_var.reg_type;
14345 switch (base_type(dst_reg->type)) {
14347 dst_reg->mem_size = aux->btf_var.mem_size;
14349 case PTR_TO_BTF_ID:
14350 dst_reg->btf = aux->btf_var.btf;
14351 dst_reg->btf_id = aux->btf_var.btf_id;
14354 verbose(env, "bpf verifier is misconfigured\n");
14360 if (insn->src_reg == BPF_PSEUDO_FUNC) {
14361 struct bpf_prog_aux *aux = env->prog->aux;
14362 u32 subprogno = find_subprog(env,
14363 env->insn_idx + insn->imm + 1);
14365 if (!aux->func_info) {
14366 verbose(env, "missing btf func_info\n");
14369 if (aux->func_info_aux[subprogno].linkage != BTF_FUNC_STATIC) {
14370 verbose(env, "callback function not static\n");
14374 dst_reg->type = PTR_TO_FUNC;
14375 dst_reg->subprogno = subprogno;
14379 map = env->used_maps[aux->map_index];
14380 dst_reg->map_ptr = map;
14382 if (insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
14383 insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
14384 dst_reg->type = PTR_TO_MAP_VALUE;
14385 dst_reg->off = aux->map_off;
14386 WARN_ON_ONCE(map->max_entries != 1);
14387 /* We want reg->id to be same (0) as map_value is not distinct */
14388 } else if (insn->src_reg == BPF_PSEUDO_MAP_FD ||
14389 insn->src_reg == BPF_PSEUDO_MAP_IDX) {
14390 dst_reg->type = CONST_PTR_TO_MAP;
14392 verbose(env, "bpf verifier is misconfigured\n");
14399 static bool may_access_skb(enum bpf_prog_type type)
14402 case BPF_PROG_TYPE_SOCKET_FILTER:
14403 case BPF_PROG_TYPE_SCHED_CLS:
14404 case BPF_PROG_TYPE_SCHED_ACT:
14411 /* verify safety of LD_ABS|LD_IND instructions:
14412 * - they can only appear in the programs where ctx == skb
14413 * - since they are wrappers of function calls, they scratch R1-R5 registers,
14414 * preserve R6-R9, and store return value into R0
14417 * ctx == skb == R6 == CTX
14420 * SRC == any register
14421 * IMM == 32-bit immediate
14424 * R0 - 8/16/32-bit skb data converted to cpu endianness
14426 static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
14428 struct bpf_reg_state *regs = cur_regs(env);
14429 static const int ctx_reg = BPF_REG_6;
14430 u8 mode = BPF_MODE(insn->code);
14433 if (!may_access_skb(resolve_prog_type(env->prog))) {
14434 verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
14438 if (!env->ops->gen_ld_abs) {
14439 verbose(env, "bpf verifier is misconfigured\n");
14443 if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
14444 BPF_SIZE(insn->code) == BPF_DW ||
14445 (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
14446 verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n");
14450 /* check whether implicit source operand (register R6) is readable */
14451 err = check_reg_arg(env, ctx_reg, SRC_OP);
14455 /* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
14456 * gen_ld_abs() may terminate the program at runtime, leading to
14459 err = check_reference_leak(env);
14461 verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
14465 if (env->cur_state->active_lock.ptr) {
14466 verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
14470 if (env->cur_state->active_rcu_lock) {
14471 verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_rcu_read_lock-ed region\n");
14475 if (regs[ctx_reg].type != PTR_TO_CTX) {
14477 "at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
14481 if (mode == BPF_IND) {
14482 /* check explicit source operand */
14483 err = check_reg_arg(env, insn->src_reg, SRC_OP);
14488 err = check_ptr_off_reg(env, ®s[ctx_reg], ctx_reg);
14492 /* reset caller saved regs to unreadable */
14493 for (i = 0; i < CALLER_SAVED_REGS; i++) {
14494 mark_reg_not_init(env, regs, caller_saved[i]);
14495 check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
14498 /* mark destination R0 register as readable, since it contains
14499 * the value fetched from the packet.
14500 * Already marked as written above.
14502 mark_reg_unknown(env, regs, BPF_REG_0);
14503 /* ld_abs load up to 32-bit skb data. */
14504 regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
14508 static int check_return_code(struct bpf_verifier_env *env)
14510 struct tnum enforce_attach_type_range = tnum_unknown;
14511 const struct bpf_prog *prog = env->prog;
14512 struct bpf_reg_state *reg;
14513 struct tnum range = tnum_range(0, 1), const_0 = tnum_const(0);
14514 enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
14516 struct bpf_func_state *frame = env->cur_state->frame[0];
14517 const bool is_subprog = frame->subprogno;
14519 /* LSM and struct_ops func-ptr's return type could be "void" */
14521 switch (prog_type) {
14522 case BPF_PROG_TYPE_LSM:
14523 if (prog->expected_attach_type == BPF_LSM_CGROUP)
14524 /* See below, can be 0 or 0-1 depending on hook. */
14527 case BPF_PROG_TYPE_STRUCT_OPS:
14528 if (!prog->aux->attach_func_proto->type)
14536 /* eBPF calling convention is such that R0 is used
14537 * to return the value from eBPF program.
14538 * Make sure that it's readable at this time
14539 * of bpf_exit, which means that program wrote
14540 * something into it earlier
14542 err = check_reg_arg(env, BPF_REG_0, SRC_OP);
14546 if (is_pointer_value(env, BPF_REG_0)) {
14547 verbose(env, "R0 leaks addr as return value\n");
14551 reg = cur_regs(env) + BPF_REG_0;
14553 if (frame->in_async_callback_fn) {
14554 /* enforce return zero from async callbacks like timer */
14555 if (reg->type != SCALAR_VALUE) {
14556 verbose(env, "In async callback the register R0 is not a known value (%s)\n",
14557 reg_type_str(env, reg->type));
14561 if (!tnum_in(const_0, reg->var_off)) {
14562 verbose_invalid_scalar(env, reg, &const_0, "async callback", "R0");
14569 if (reg->type != SCALAR_VALUE) {
14570 verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
14571 reg_type_str(env, reg->type));
14577 switch (prog_type) {
14578 case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
14579 if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
14580 env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG ||
14581 env->prog->expected_attach_type == BPF_CGROUP_INET4_GETPEERNAME ||
14582 env->prog->expected_attach_type == BPF_CGROUP_INET6_GETPEERNAME ||
14583 env->prog->expected_attach_type == BPF_CGROUP_INET4_GETSOCKNAME ||
14584 env->prog->expected_attach_type == BPF_CGROUP_INET6_GETSOCKNAME)
14585 range = tnum_range(1, 1);
14586 if (env->prog->expected_attach_type == BPF_CGROUP_INET4_BIND ||
14587 env->prog->expected_attach_type == BPF_CGROUP_INET6_BIND)
14588 range = tnum_range(0, 3);
14590 case BPF_PROG_TYPE_CGROUP_SKB:
14591 if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
14592 range = tnum_range(0, 3);
14593 enforce_attach_type_range = tnum_range(2, 3);
14596 case BPF_PROG_TYPE_CGROUP_SOCK:
14597 case BPF_PROG_TYPE_SOCK_OPS:
14598 case BPF_PROG_TYPE_CGROUP_DEVICE:
14599 case BPF_PROG_TYPE_CGROUP_SYSCTL:
14600 case BPF_PROG_TYPE_CGROUP_SOCKOPT:
14602 case BPF_PROG_TYPE_RAW_TRACEPOINT:
14603 if (!env->prog->aux->attach_btf_id)
14605 range = tnum_const(0);
14607 case BPF_PROG_TYPE_TRACING:
14608 switch (env->prog->expected_attach_type) {
14609 case BPF_TRACE_FENTRY:
14610 case BPF_TRACE_FEXIT:
14611 range = tnum_const(0);
14613 case BPF_TRACE_RAW_TP:
14614 case BPF_MODIFY_RETURN:
14616 case BPF_TRACE_ITER:
14622 case BPF_PROG_TYPE_SK_LOOKUP:
14623 range = tnum_range(SK_DROP, SK_PASS);
14626 case BPF_PROG_TYPE_LSM:
14627 if (env->prog->expected_attach_type != BPF_LSM_CGROUP) {
14628 /* Regular BPF_PROG_TYPE_LSM programs can return
14633 if (!env->prog->aux->attach_func_proto->type) {
14634 /* Make sure programs that attach to void
14635 * hooks don't try to modify return value.
14637 range = tnum_range(1, 1);
14641 case BPF_PROG_TYPE_NETFILTER:
14642 range = tnum_range(NF_DROP, NF_ACCEPT);
14644 case BPF_PROG_TYPE_EXT:
14645 /* freplace program can return anything as its return value
14646 * depends on the to-be-replaced kernel func or bpf program.
14652 if (reg->type != SCALAR_VALUE) {
14653 verbose(env, "At program exit the register R0 is not a known value (%s)\n",
14654 reg_type_str(env, reg->type));
14658 if (!tnum_in(range, reg->var_off)) {
14659 verbose_invalid_scalar(env, reg, &range, "program exit", "R0");
14660 if (prog->expected_attach_type == BPF_LSM_CGROUP &&
14661 prog_type == BPF_PROG_TYPE_LSM &&
14662 !prog->aux->attach_func_proto->type)
14663 verbose(env, "Note, BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
14667 if (!tnum_is_unknown(enforce_attach_type_range) &&
14668 tnum_in(enforce_attach_type_range, reg->var_off))
14669 env->prog->enforce_expected_attach_type = 1;
14673 /* non-recursive DFS pseudo code
14674 * 1 procedure DFS-iterative(G,v):
14675 * 2 label v as discovered
14676 * 3 let S be a stack
14678 * 5 while S is not empty
14680 * 7 if t is what we're looking for:
14682 * 9 for all edges e in G.adjacentEdges(t) do
14683 * 10 if edge e is already labelled
14684 * 11 continue with the next edge
14685 * 12 w <- G.adjacentVertex(t,e)
14686 * 13 if vertex w is not discovered and not explored
14687 * 14 label e as tree-edge
14688 * 15 label w as discovered
14691 * 18 else if vertex w is discovered
14692 * 19 label e as back-edge
14694 * 21 // vertex w is explored
14695 * 22 label e as forward- or cross-edge
14696 * 23 label t as explored
14700 * 0x10 - discovered
14701 * 0x11 - discovered and fall-through edge labelled
14702 * 0x12 - discovered and fall-through and branch edges labelled
14713 static u32 state_htab_size(struct bpf_verifier_env *env)
14715 return env->prog->len;
14718 static struct bpf_verifier_state_list **explored_state(
14719 struct bpf_verifier_env *env,
14722 struct bpf_verifier_state *cur = env->cur_state;
14723 struct bpf_func_state *state = cur->frame[cur->curframe];
14725 return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
14728 static void mark_prune_point(struct bpf_verifier_env *env, int idx)
14730 env->insn_aux_data[idx].prune_point = true;
14733 static bool is_prune_point(struct bpf_verifier_env *env, int insn_idx)
14735 return env->insn_aux_data[insn_idx].prune_point;
14738 static void mark_force_checkpoint(struct bpf_verifier_env *env, int idx)
14740 env->insn_aux_data[idx].force_checkpoint = true;
14743 static bool is_force_checkpoint(struct bpf_verifier_env *env, int insn_idx)
14745 return env->insn_aux_data[insn_idx].force_checkpoint;
14750 DONE_EXPLORING = 0,
14751 KEEP_EXPLORING = 1,
14754 /* t, w, e - match pseudo-code above:
14755 * t - index of current instruction
14756 * w - next instruction
14759 static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
14761 int *insn_stack = env->cfg.insn_stack;
14762 int *insn_state = env->cfg.insn_state;
14764 if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
14765 return DONE_EXPLORING;
14767 if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
14768 return DONE_EXPLORING;
14770 if (w < 0 || w >= env->prog->len) {
14771 verbose_linfo(env, t, "%d: ", t);
14772 verbose(env, "jump out of range from insn %d to %d\n", t, w);
14777 /* mark branch target for state pruning */
14778 mark_prune_point(env, w);
14779 mark_jmp_point(env, w);
14782 if (insn_state[w] == 0) {
14784 insn_state[t] = DISCOVERED | e;
14785 insn_state[w] = DISCOVERED;
14786 if (env->cfg.cur_stack >= env->prog->len)
14788 insn_stack[env->cfg.cur_stack++] = w;
14789 return KEEP_EXPLORING;
14790 } else if ((insn_state[w] & 0xF0) == DISCOVERED) {
14791 if (env->bpf_capable)
14792 return DONE_EXPLORING;
14793 verbose_linfo(env, t, "%d: ", t);
14794 verbose_linfo(env, w, "%d: ", w);
14795 verbose(env, "back-edge from insn %d to %d\n", t, w);
14797 } else if (insn_state[w] == EXPLORED) {
14798 /* forward- or cross-edge */
14799 insn_state[t] = DISCOVERED | e;
14801 verbose(env, "insn state internal bug\n");
14804 return DONE_EXPLORING;
14807 static int visit_func_call_insn(int t, struct bpf_insn *insns,
14808 struct bpf_verifier_env *env,
14813 insn_sz = bpf_is_ldimm64(&insns[t]) ? 2 : 1;
14814 ret = push_insn(t, t + insn_sz, FALLTHROUGH, env);
14818 mark_prune_point(env, t + insn_sz);
14819 /* when we exit from subprog, we need to record non-linear history */
14820 mark_jmp_point(env, t + insn_sz);
14822 if (visit_callee) {
14823 mark_prune_point(env, t);
14824 ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
14829 /* Visits the instruction at index t and returns one of the following:
14830 * < 0 - an error occurred
14831 * DONE_EXPLORING - the instruction was fully explored
14832 * KEEP_EXPLORING - there is still work to be done before it is fully explored
14834 static int visit_insn(int t, struct bpf_verifier_env *env)
14836 struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
14837 int ret, off, insn_sz;
14839 if (bpf_pseudo_func(insn))
14840 return visit_func_call_insn(t, insns, env, true);
14842 /* All non-branch instructions have a single fall-through edge. */
14843 if (BPF_CLASS(insn->code) != BPF_JMP &&
14844 BPF_CLASS(insn->code) != BPF_JMP32) {
14845 insn_sz = bpf_is_ldimm64(insn) ? 2 : 1;
14846 return push_insn(t, t + insn_sz, FALLTHROUGH, env);
14849 switch (BPF_OP(insn->code)) {
14851 return DONE_EXPLORING;
14854 if (insn->src_reg == 0 && insn->imm == BPF_FUNC_timer_set_callback)
14855 /* Mark this call insn as a prune point to trigger
14856 * is_state_visited() check before call itself is
14857 * processed by __check_func_call(). Otherwise new
14858 * async state will be pushed for further exploration.
14860 mark_prune_point(env, t);
14861 if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
14862 struct bpf_kfunc_call_arg_meta meta;
14864 ret = fetch_kfunc_meta(env, insn, &meta, NULL);
14865 if (ret == 0 && is_iter_next_kfunc(&meta)) {
14866 mark_prune_point(env, t);
14867 /* Checking and saving state checkpoints at iter_next() call
14868 * is crucial for fast convergence of open-coded iterator loop
14869 * logic, so we need to force it. If we don't do that,
14870 * is_state_visited() might skip saving a checkpoint, causing
14871 * unnecessarily long sequence of not checkpointed
14872 * instructions and jumps, leading to exhaustion of jump
14873 * history buffer, and potentially other undesired outcomes.
14874 * It is expected that with correct open-coded iterators
14875 * convergence will happen quickly, so we don't run a risk of
14876 * exhausting memory.
14878 mark_force_checkpoint(env, t);
14881 return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
14884 if (BPF_SRC(insn->code) != BPF_K)
14887 if (BPF_CLASS(insn->code) == BPF_JMP)
14892 /* unconditional jump with single edge */
14893 ret = push_insn(t, t + off + 1, FALLTHROUGH, env);
14897 mark_prune_point(env, t + off + 1);
14898 mark_jmp_point(env, t + off + 1);
14903 /* conditional jump with two edges */
14904 mark_prune_point(env, t);
14906 ret = push_insn(t, t + 1, FALLTHROUGH, env);
14910 return push_insn(t, t + insn->off + 1, BRANCH, env);
14914 /* non-recursive depth-first-search to detect loops in BPF program
14915 * loop == back-edge in directed graph
14917 static int check_cfg(struct bpf_verifier_env *env)
14919 int insn_cnt = env->prog->len;
14920 int *insn_stack, *insn_state;
14924 insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
14928 insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
14930 kvfree(insn_state);
14934 insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
14935 insn_stack[0] = 0; /* 0 is the first instruction */
14936 env->cfg.cur_stack = 1;
14938 while (env->cfg.cur_stack > 0) {
14939 int t = insn_stack[env->cfg.cur_stack - 1];
14941 ret = visit_insn(t, env);
14943 case DONE_EXPLORING:
14944 insn_state[t] = EXPLORED;
14945 env->cfg.cur_stack--;
14947 case KEEP_EXPLORING:
14951 verbose(env, "visit_insn internal bug\n");
14958 if (env->cfg.cur_stack < 0) {
14959 verbose(env, "pop stack internal bug\n");
14964 for (i = 0; i < insn_cnt; i++) {
14965 struct bpf_insn *insn = &env->prog->insnsi[i];
14967 if (insn_state[i] != EXPLORED) {
14968 verbose(env, "unreachable insn %d\n", i);
14972 if (bpf_is_ldimm64(insn)) {
14973 if (insn_state[i + 1] != 0) {
14974 verbose(env, "jump into the middle of ldimm64 insn %d\n", i);
14978 i++; /* skip second half of ldimm64 */
14981 ret = 0; /* cfg looks good */
14984 kvfree(insn_state);
14985 kvfree(insn_stack);
14986 env->cfg.insn_state = env->cfg.insn_stack = NULL;
14990 static int check_abnormal_return(struct bpf_verifier_env *env)
14994 for (i = 1; i < env->subprog_cnt; i++) {
14995 if (env->subprog_info[i].has_ld_abs) {
14996 verbose(env, "LD_ABS is not allowed in subprogs without BTF\n");
14999 if (env->subprog_info[i].has_tail_call) {
15000 verbose(env, "tail_call is not allowed in subprogs without BTF\n");
15007 /* The minimum supported BTF func info size */
15008 #define MIN_BPF_FUNCINFO_SIZE 8
15009 #define MAX_FUNCINFO_REC_SIZE 252
15011 static int check_btf_func(struct bpf_verifier_env *env,
15012 const union bpf_attr *attr,
15015 const struct btf_type *type, *func_proto, *ret_type;
15016 u32 i, nfuncs, urec_size, min_size;
15017 u32 krec_size = sizeof(struct bpf_func_info);
15018 struct bpf_func_info *krecord;
15019 struct bpf_func_info_aux *info_aux = NULL;
15020 struct bpf_prog *prog;
15021 const struct btf *btf;
15023 u32 prev_offset = 0;
15024 bool scalar_return;
15027 nfuncs = attr->func_info_cnt;
15029 if (check_abnormal_return(env))
15034 if (nfuncs != env->subprog_cnt) {
15035 verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
15039 urec_size = attr->func_info_rec_size;
15040 if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
15041 urec_size > MAX_FUNCINFO_REC_SIZE ||
15042 urec_size % sizeof(u32)) {
15043 verbose(env, "invalid func info rec size %u\n", urec_size);
15048 btf = prog->aux->btf;
15050 urecord = make_bpfptr(attr->func_info, uattr.is_kernel);
15051 min_size = min_t(u32, krec_size, urec_size);
15053 krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
15056 info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN);
15060 for (i = 0; i < nfuncs; i++) {
15061 ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
15063 if (ret == -E2BIG) {
15064 verbose(env, "nonzero tailing record in func info");
15065 /* set the size kernel expects so loader can zero
15066 * out the rest of the record.
15068 if (copy_to_bpfptr_offset(uattr,
15069 offsetof(union bpf_attr, func_info_rec_size),
15070 &min_size, sizeof(min_size)))
15076 if (copy_from_bpfptr(&krecord[i], urecord, min_size)) {
15081 /* check insn_off */
15084 if (krecord[i].insn_off) {
15086 "nonzero insn_off %u for the first func info record",
15087 krecord[i].insn_off);
15090 } else if (krecord[i].insn_off <= prev_offset) {
15092 "same or smaller insn offset (%u) than previous func info record (%u)",
15093 krecord[i].insn_off, prev_offset);
15097 if (env->subprog_info[i].start != krecord[i].insn_off) {
15098 verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
15102 /* check type_id */
15103 type = btf_type_by_id(btf, krecord[i].type_id);
15104 if (!type || !btf_type_is_func(type)) {
15105 verbose(env, "invalid type id %d in func info",
15106 krecord[i].type_id);
15109 info_aux[i].linkage = BTF_INFO_VLEN(type->info);
15111 func_proto = btf_type_by_id(btf, type->type);
15112 if (unlikely(!func_proto || !btf_type_is_func_proto(func_proto)))
15113 /* btf_func_check() already verified it during BTF load */
15115 ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL);
15117 btf_type_is_small_int(ret_type) || btf_is_any_enum(ret_type);
15118 if (i && !scalar_return && env->subprog_info[i].has_ld_abs) {
15119 verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n");
15122 if (i && !scalar_return && env->subprog_info[i].has_tail_call) {
15123 verbose(env, "tail_call is only allowed in functions that return 'int'.\n");
15127 prev_offset = krecord[i].insn_off;
15128 bpfptr_add(&urecord, urec_size);
15131 prog->aux->func_info = krecord;
15132 prog->aux->func_info_cnt = nfuncs;
15133 prog->aux->func_info_aux = info_aux;
15142 static void adjust_btf_func(struct bpf_verifier_env *env)
15144 struct bpf_prog_aux *aux = env->prog->aux;
15147 if (!aux->func_info)
15150 for (i = 0; i < env->subprog_cnt; i++)
15151 aux->func_info[i].insn_off = env->subprog_info[i].start;
15154 #define MIN_BPF_LINEINFO_SIZE offsetofend(struct bpf_line_info, line_col)
15155 #define MAX_LINEINFO_REC_SIZE MAX_FUNCINFO_REC_SIZE
15157 static int check_btf_line(struct bpf_verifier_env *env,
15158 const union bpf_attr *attr,
15161 u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
15162 struct bpf_subprog_info *sub;
15163 struct bpf_line_info *linfo;
15164 struct bpf_prog *prog;
15165 const struct btf *btf;
15169 nr_linfo = attr->line_info_cnt;
15172 if (nr_linfo > INT_MAX / sizeof(struct bpf_line_info))
15175 rec_size = attr->line_info_rec_size;
15176 if (rec_size < MIN_BPF_LINEINFO_SIZE ||
15177 rec_size > MAX_LINEINFO_REC_SIZE ||
15178 rec_size & (sizeof(u32) - 1))
15181 /* Need to zero it in case the userspace may
15182 * pass in a smaller bpf_line_info object.
15184 linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
15185 GFP_KERNEL | __GFP_NOWARN);
15190 btf = prog->aux->btf;
15193 sub = env->subprog_info;
15194 ulinfo = make_bpfptr(attr->line_info, uattr.is_kernel);
15195 expected_size = sizeof(struct bpf_line_info);
15196 ncopy = min_t(u32, expected_size, rec_size);
15197 for (i = 0; i < nr_linfo; i++) {
15198 err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
15200 if (err == -E2BIG) {
15201 verbose(env, "nonzero tailing record in line_info");
15202 if (copy_to_bpfptr_offset(uattr,
15203 offsetof(union bpf_attr, line_info_rec_size),
15204 &expected_size, sizeof(expected_size)))
15210 if (copy_from_bpfptr(&linfo[i], ulinfo, ncopy)) {
15216 * Check insn_off to ensure
15217 * 1) strictly increasing AND
15218 * 2) bounded by prog->len
15220 * The linfo[0].insn_off == 0 check logically falls into
15221 * the later "missing bpf_line_info for func..." case
15222 * because the first linfo[0].insn_off must be the
15223 * first sub also and the first sub must have
15224 * subprog_info[0].start == 0.
15226 if ((i && linfo[i].insn_off <= prev_offset) ||
15227 linfo[i].insn_off >= prog->len) {
15228 verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
15229 i, linfo[i].insn_off, prev_offset,
15235 if (!prog->insnsi[linfo[i].insn_off].code) {
15237 "Invalid insn code at line_info[%u].insn_off\n",
15243 if (!btf_name_by_offset(btf, linfo[i].line_off) ||
15244 !btf_name_by_offset(btf, linfo[i].file_name_off)) {
15245 verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
15250 if (s != env->subprog_cnt) {
15251 if (linfo[i].insn_off == sub[s].start) {
15252 sub[s].linfo_idx = i;
15254 } else if (sub[s].start < linfo[i].insn_off) {
15255 verbose(env, "missing bpf_line_info for func#%u\n", s);
15261 prev_offset = linfo[i].insn_off;
15262 bpfptr_add(&ulinfo, rec_size);
15265 if (s != env->subprog_cnt) {
15266 verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
15267 env->subprog_cnt - s, s);
15272 prog->aux->linfo = linfo;
15273 prog->aux->nr_linfo = nr_linfo;
15282 #define MIN_CORE_RELO_SIZE sizeof(struct bpf_core_relo)
15283 #define MAX_CORE_RELO_SIZE MAX_FUNCINFO_REC_SIZE
15285 static int check_core_relo(struct bpf_verifier_env *env,
15286 const union bpf_attr *attr,
15289 u32 i, nr_core_relo, ncopy, expected_size, rec_size;
15290 struct bpf_core_relo core_relo = {};
15291 struct bpf_prog *prog = env->prog;
15292 const struct btf *btf = prog->aux->btf;
15293 struct bpf_core_ctx ctx = {
15297 bpfptr_t u_core_relo;
15300 nr_core_relo = attr->core_relo_cnt;
15303 if (nr_core_relo > INT_MAX / sizeof(struct bpf_core_relo))
15306 rec_size = attr->core_relo_rec_size;
15307 if (rec_size < MIN_CORE_RELO_SIZE ||
15308 rec_size > MAX_CORE_RELO_SIZE ||
15309 rec_size % sizeof(u32))
15312 u_core_relo = make_bpfptr(attr->core_relos, uattr.is_kernel);
15313 expected_size = sizeof(struct bpf_core_relo);
15314 ncopy = min_t(u32, expected_size, rec_size);
15316 /* Unlike func_info and line_info, copy and apply each CO-RE
15317 * relocation record one at a time.
15319 for (i = 0; i < nr_core_relo; i++) {
15320 /* future proofing when sizeof(bpf_core_relo) changes */
15321 err = bpf_check_uarg_tail_zero(u_core_relo, expected_size, rec_size);
15323 if (err == -E2BIG) {
15324 verbose(env, "nonzero tailing record in core_relo");
15325 if (copy_to_bpfptr_offset(uattr,
15326 offsetof(union bpf_attr, core_relo_rec_size),
15327 &expected_size, sizeof(expected_size)))
15333 if (copy_from_bpfptr(&core_relo, u_core_relo, ncopy)) {
15338 if (core_relo.insn_off % 8 || core_relo.insn_off / 8 >= prog->len) {
15339 verbose(env, "Invalid core_relo[%u].insn_off:%u prog->len:%u\n",
15340 i, core_relo.insn_off, prog->len);
15345 err = bpf_core_apply(&ctx, &core_relo, i,
15346 &prog->insnsi[core_relo.insn_off / 8]);
15349 bpfptr_add(&u_core_relo, rec_size);
15354 static int check_btf_info(struct bpf_verifier_env *env,
15355 const union bpf_attr *attr,
15361 if (!attr->func_info_cnt && !attr->line_info_cnt) {
15362 if (check_abnormal_return(env))
15367 btf = btf_get_by_fd(attr->prog_btf_fd);
15369 return PTR_ERR(btf);
15370 if (btf_is_kernel(btf)) {
15374 env->prog->aux->btf = btf;
15376 err = check_btf_func(env, attr, uattr);
15380 err = check_btf_line(env, attr, uattr);
15384 err = check_core_relo(env, attr, uattr);
15391 /* check %cur's range satisfies %old's */
15392 static bool range_within(struct bpf_reg_state *old,
15393 struct bpf_reg_state *cur)
15395 return old->umin_value <= cur->umin_value &&
15396 old->umax_value >= cur->umax_value &&
15397 old->smin_value <= cur->smin_value &&
15398 old->smax_value >= cur->smax_value &&
15399 old->u32_min_value <= cur->u32_min_value &&
15400 old->u32_max_value >= cur->u32_max_value &&
15401 old->s32_min_value <= cur->s32_min_value &&
15402 old->s32_max_value >= cur->s32_max_value;
15405 /* If in the old state two registers had the same id, then they need to have
15406 * the same id in the new state as well. But that id could be different from
15407 * the old state, so we need to track the mapping from old to new ids.
15408 * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
15409 * regs with old id 5 must also have new id 9 for the new state to be safe. But
15410 * regs with a different old id could still have new id 9, we don't care about
15412 * So we look through our idmap to see if this old id has been seen before. If
15413 * so, we require the new id to match; otherwise, we add the id pair to the map.
15415 static bool check_ids(u32 old_id, u32 cur_id, struct bpf_idmap *idmap)
15417 struct bpf_id_pair *map = idmap->map;
15420 /* either both IDs should be set or both should be zero */
15421 if (!!old_id != !!cur_id)
15424 if (old_id == 0) /* cur_id == 0 as well */
15427 for (i = 0; i < BPF_ID_MAP_SIZE; i++) {
15429 /* Reached an empty slot; haven't seen this id before */
15430 map[i].old = old_id;
15431 map[i].cur = cur_id;
15434 if (map[i].old == old_id)
15435 return map[i].cur == cur_id;
15436 if (map[i].cur == cur_id)
15439 /* We ran out of idmap slots, which should be impossible */
15444 /* Similar to check_ids(), but allocate a unique temporary ID
15445 * for 'old_id' or 'cur_id' of zero.
15446 * This makes pairs like '0 vs unique ID', 'unique ID vs 0' valid.
15448 static bool check_scalar_ids(u32 old_id, u32 cur_id, struct bpf_idmap *idmap)
15450 old_id = old_id ? old_id : ++idmap->tmp_id_gen;
15451 cur_id = cur_id ? cur_id : ++idmap->tmp_id_gen;
15453 return check_ids(old_id, cur_id, idmap);
15456 static void clean_func_state(struct bpf_verifier_env *env,
15457 struct bpf_func_state *st)
15459 enum bpf_reg_liveness live;
15462 for (i = 0; i < BPF_REG_FP; i++) {
15463 live = st->regs[i].live;
15464 /* liveness must not touch this register anymore */
15465 st->regs[i].live |= REG_LIVE_DONE;
15466 if (!(live & REG_LIVE_READ))
15467 /* since the register is unused, clear its state
15468 * to make further comparison simpler
15470 __mark_reg_not_init(env, &st->regs[i]);
15473 for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
15474 live = st->stack[i].spilled_ptr.live;
15475 /* liveness must not touch this stack slot anymore */
15476 st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
15477 if (!(live & REG_LIVE_READ)) {
15478 __mark_reg_not_init(env, &st->stack[i].spilled_ptr);
15479 for (j = 0; j < BPF_REG_SIZE; j++)
15480 st->stack[i].slot_type[j] = STACK_INVALID;
15485 static void clean_verifier_state(struct bpf_verifier_env *env,
15486 struct bpf_verifier_state *st)
15490 if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
15491 /* all regs in this state in all frames were already marked */
15494 for (i = 0; i <= st->curframe; i++)
15495 clean_func_state(env, st->frame[i]);
15498 /* the parentage chains form a tree.
15499 * the verifier states are added to state lists at given insn and
15500 * pushed into state stack for future exploration.
15501 * when the verifier reaches bpf_exit insn some of the verifer states
15502 * stored in the state lists have their final liveness state already,
15503 * but a lot of states will get revised from liveness point of view when
15504 * the verifier explores other branches.
15507 * 2: if r1 == 100 goto pc+1
15510 * when the verifier reaches exit insn the register r0 in the state list of
15511 * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
15512 * of insn 2 and goes exploring further. At the insn 4 it will walk the
15513 * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
15515 * Since the verifier pushes the branch states as it sees them while exploring
15516 * the program the condition of walking the branch instruction for the second
15517 * time means that all states below this branch were already explored and
15518 * their final liveness marks are already propagated.
15519 * Hence when the verifier completes the search of state list in is_state_visited()
15520 * we can call this clean_live_states() function to mark all liveness states
15521 * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
15522 * will not be used.
15523 * This function also clears the registers and stack for states that !READ
15524 * to simplify state merging.
15526 * Important note here that walking the same branch instruction in the callee
15527 * doesn't meant that the states are DONE. The verifier has to compare
15530 static void clean_live_states(struct bpf_verifier_env *env, int insn,
15531 struct bpf_verifier_state *cur)
15533 struct bpf_verifier_state_list *sl;
15536 sl = *explored_state(env, insn);
15538 if (sl->state.branches)
15540 if (sl->state.insn_idx != insn ||
15541 sl->state.curframe != cur->curframe)
15543 for (i = 0; i <= cur->curframe; i++)
15544 if (sl->state.frame[i]->callsite != cur->frame[i]->callsite)
15546 clean_verifier_state(env, &sl->state);
15552 static bool regs_exact(const struct bpf_reg_state *rold,
15553 const struct bpf_reg_state *rcur,
15554 struct bpf_idmap *idmap)
15556 return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
15557 check_ids(rold->id, rcur->id, idmap) &&
15558 check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
15561 /* Returns true if (rold safe implies rcur safe) */
15562 static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
15563 struct bpf_reg_state *rcur, struct bpf_idmap *idmap)
15565 if (!(rold->live & REG_LIVE_READ))
15566 /* explored state didn't use this */
15568 if (rold->type == NOT_INIT)
15569 /* explored state can't have used this */
15571 if (rcur->type == NOT_INIT)
15574 /* Enforce that register types have to match exactly, including their
15575 * modifiers (like PTR_MAYBE_NULL, MEM_RDONLY, etc), as a general
15578 * One can make a point that using a pointer register as unbounded
15579 * SCALAR would be technically acceptable, but this could lead to
15580 * pointer leaks because scalars are allowed to leak while pointers
15581 * are not. We could make this safe in special cases if root is
15582 * calling us, but it's probably not worth the hassle.
15584 * Also, register types that are *not* MAYBE_NULL could technically be
15585 * safe to use as their MAYBE_NULL variants (e.g., PTR_TO_MAP_VALUE
15586 * is safe to be used as PTR_TO_MAP_VALUE_OR_NULL, provided both point
15587 * to the same map).
15588 * However, if the old MAYBE_NULL register then got NULL checked,
15589 * doing so could have affected others with the same id, and we can't
15590 * check for that because we lost the id when we converted to
15591 * a non-MAYBE_NULL variant.
15592 * So, as a general rule we don't allow mixing MAYBE_NULL and
15593 * non-MAYBE_NULL registers as well.
15595 if (rold->type != rcur->type)
15598 switch (base_type(rold->type)) {
15600 if (env->explore_alu_limits) {
15601 /* explore_alu_limits disables tnum_in() and range_within()
15602 * logic and requires everything to be strict
15604 return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
15605 check_scalar_ids(rold->id, rcur->id, idmap);
15607 if (!rold->precise)
15609 /* Why check_ids() for scalar registers?
15611 * Consider the following BPF code:
15612 * 1: r6 = ... unbound scalar, ID=a ...
15613 * 2: r7 = ... unbound scalar, ID=b ...
15614 * 3: if (r6 > r7) goto +1
15616 * 5: if (r6 > X) goto ...
15617 * 6: ... memory operation using r7 ...
15619 * First verification path is [1-6]:
15620 * - at (4) same bpf_reg_state::id (b) would be assigned to r6 and r7;
15621 * - at (5) r6 would be marked <= X, find_equal_scalars() would also mark
15622 * r7 <= X, because r6 and r7 share same id.
15623 * Next verification path is [1-4, 6].
15625 * Instruction (6) would be reached in two states:
15626 * I. r6{.id=b}, r7{.id=b} via path 1-6;
15627 * II. r6{.id=a}, r7{.id=b} via path 1-4, 6.
15629 * Use check_ids() to distinguish these states.
15631 * Also verify that new value satisfies old value range knowledge.
15633 return range_within(rold, rcur) &&
15634 tnum_in(rold->var_off, rcur->var_off) &&
15635 check_scalar_ids(rold->id, rcur->id, idmap);
15636 case PTR_TO_MAP_KEY:
15637 case PTR_TO_MAP_VALUE:
15640 case PTR_TO_TP_BUFFER:
15641 /* If the new min/max/var_off satisfy the old ones and
15642 * everything else matches, we are OK.
15644 return memcmp(rold, rcur, offsetof(struct bpf_reg_state, var_off)) == 0 &&
15645 range_within(rold, rcur) &&
15646 tnum_in(rold->var_off, rcur->var_off) &&
15647 check_ids(rold->id, rcur->id, idmap) &&
15648 check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
15649 case PTR_TO_PACKET_META:
15650 case PTR_TO_PACKET:
15651 /* We must have at least as much range as the old ptr
15652 * did, so that any accesses which were safe before are
15653 * still safe. This is true even if old range < old off,
15654 * since someone could have accessed through (ptr - k), or
15655 * even done ptr -= k in a register, to get a safe access.
15657 if (rold->range > rcur->range)
15659 /* If the offsets don't match, we can't trust our alignment;
15660 * nor can we be sure that we won't fall out of range.
15662 if (rold->off != rcur->off)
15664 /* id relations must be preserved */
15665 if (!check_ids(rold->id, rcur->id, idmap))
15667 /* new val must satisfy old val knowledge */
15668 return range_within(rold, rcur) &&
15669 tnum_in(rold->var_off, rcur->var_off);
15671 /* two stack pointers are equal only if they're pointing to
15672 * the same stack frame, since fp-8 in foo != fp-8 in bar
15674 return regs_exact(rold, rcur, idmap) && rold->frameno == rcur->frameno;
15676 return regs_exact(rold, rcur, idmap);
15680 static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old,
15681 struct bpf_func_state *cur, struct bpf_idmap *idmap)
15685 /* walk slots of the explored stack and ignore any additional
15686 * slots in the current stack, since explored(safe) state
15689 for (i = 0; i < old->allocated_stack; i++) {
15690 struct bpf_reg_state *old_reg, *cur_reg;
15692 spi = i / BPF_REG_SIZE;
15694 if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) {
15695 i += BPF_REG_SIZE - 1;
15696 /* explored state didn't use this */
15700 if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
15703 if (env->allow_uninit_stack &&
15704 old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC)
15707 /* explored stack has more populated slots than current stack
15708 * and these slots were used
15710 if (i >= cur->allocated_stack)
15713 /* if old state was safe with misc data in the stack
15714 * it will be safe with zero-initialized stack.
15715 * The opposite is not true
15717 if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC &&
15718 cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO)
15720 if (old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
15721 cur->stack[spi].slot_type[i % BPF_REG_SIZE])
15722 /* Ex: old explored (safe) state has STACK_SPILL in
15723 * this stack slot, but current has STACK_MISC ->
15724 * this verifier states are not equivalent,
15725 * return false to continue verification of this path
15728 if (i % BPF_REG_SIZE != BPF_REG_SIZE - 1)
15730 /* Both old and cur are having same slot_type */
15731 switch (old->stack[spi].slot_type[BPF_REG_SIZE - 1]) {
15733 /* when explored and current stack slot are both storing
15734 * spilled registers, check that stored pointers types
15735 * are the same as well.
15736 * Ex: explored safe path could have stored
15737 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
15738 * but current path has stored:
15739 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
15740 * such verifier states are not equivalent.
15741 * return false to continue verification of this path
15743 if (!regsafe(env, &old->stack[spi].spilled_ptr,
15744 &cur->stack[spi].spilled_ptr, idmap))
15748 old_reg = &old->stack[spi].spilled_ptr;
15749 cur_reg = &cur->stack[spi].spilled_ptr;
15750 if (old_reg->dynptr.type != cur_reg->dynptr.type ||
15751 old_reg->dynptr.first_slot != cur_reg->dynptr.first_slot ||
15752 !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
15756 old_reg = &old->stack[spi].spilled_ptr;
15757 cur_reg = &cur->stack[spi].spilled_ptr;
15758 /* iter.depth is not compared between states as it
15759 * doesn't matter for correctness and would otherwise
15760 * prevent convergence; we maintain it only to prevent
15761 * infinite loop check triggering, see
15762 * iter_active_depths_differ()
15764 if (old_reg->iter.btf != cur_reg->iter.btf ||
15765 old_reg->iter.btf_id != cur_reg->iter.btf_id ||
15766 old_reg->iter.state != cur_reg->iter.state ||
15767 /* ignore {old_reg,cur_reg}->iter.depth, see above */
15768 !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
15773 case STACK_INVALID:
15775 /* Ensure that new unhandled slot types return false by default */
15783 static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur,
15784 struct bpf_idmap *idmap)
15788 if (old->acquired_refs != cur->acquired_refs)
15791 for (i = 0; i < old->acquired_refs; i++) {
15792 if (!check_ids(old->refs[i].id, cur->refs[i].id, idmap))
15799 /* compare two verifier states
15801 * all states stored in state_list are known to be valid, since
15802 * verifier reached 'bpf_exit' instruction through them
15804 * this function is called when verifier exploring different branches of
15805 * execution popped from the state stack. If it sees an old state that has
15806 * more strict register state and more strict stack state then this execution
15807 * branch doesn't need to be explored further, since verifier already
15808 * concluded that more strict state leads to valid finish.
15810 * Therefore two states are equivalent if register state is more conservative
15811 * and explored stack state is more conservative than the current one.
15814 * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
15815 * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
15817 * In other words if current stack state (one being explored) has more
15818 * valid slots than old one that already passed validation, it means
15819 * the verifier can stop exploring and conclude that current state is valid too
15821 * Similarly with registers. If explored state has register type as invalid
15822 * whereas register type in current state is meaningful, it means that
15823 * the current state will reach 'bpf_exit' instruction safely
15825 static bool func_states_equal(struct bpf_verifier_env *env, struct bpf_func_state *old,
15826 struct bpf_func_state *cur)
15830 for (i = 0; i < MAX_BPF_REG; i++)
15831 if (!regsafe(env, &old->regs[i], &cur->regs[i],
15832 &env->idmap_scratch))
15835 if (!stacksafe(env, old, cur, &env->idmap_scratch))
15838 if (!refsafe(old, cur, &env->idmap_scratch))
15844 static bool states_equal(struct bpf_verifier_env *env,
15845 struct bpf_verifier_state *old,
15846 struct bpf_verifier_state *cur)
15850 if (old->curframe != cur->curframe)
15853 env->idmap_scratch.tmp_id_gen = env->id_gen;
15854 memset(&env->idmap_scratch.map, 0, sizeof(env->idmap_scratch.map));
15856 /* Verification state from speculative execution simulation
15857 * must never prune a non-speculative execution one.
15859 if (old->speculative && !cur->speculative)
15862 if (old->active_lock.ptr != cur->active_lock.ptr)
15865 /* Old and cur active_lock's have to be either both present
15868 if (!!old->active_lock.id != !!cur->active_lock.id)
15871 if (old->active_lock.id &&
15872 !check_ids(old->active_lock.id, cur->active_lock.id, &env->idmap_scratch))
15875 if (old->active_rcu_lock != cur->active_rcu_lock)
15878 /* for states to be equal callsites have to be the same
15879 * and all frame states need to be equivalent
15881 for (i = 0; i <= old->curframe; i++) {
15882 if (old->frame[i]->callsite != cur->frame[i]->callsite)
15884 if (!func_states_equal(env, old->frame[i], cur->frame[i]))
15890 /* Return 0 if no propagation happened. Return negative error code if error
15891 * happened. Otherwise, return the propagated bit.
15893 static int propagate_liveness_reg(struct bpf_verifier_env *env,
15894 struct bpf_reg_state *reg,
15895 struct bpf_reg_state *parent_reg)
15897 u8 parent_flag = parent_reg->live & REG_LIVE_READ;
15898 u8 flag = reg->live & REG_LIVE_READ;
15901 /* When comes here, read flags of PARENT_REG or REG could be any of
15902 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
15903 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
15905 if (parent_flag == REG_LIVE_READ64 ||
15906 /* Or if there is no read flag from REG. */
15908 /* Or if the read flag from REG is the same as PARENT_REG. */
15909 parent_flag == flag)
15912 err = mark_reg_read(env, reg, parent_reg, flag);
15919 /* A write screens off any subsequent reads; but write marks come from the
15920 * straight-line code between a state and its parent. When we arrive at an
15921 * equivalent state (jump target or such) we didn't arrive by the straight-line
15922 * code, so read marks in the state must propagate to the parent regardless
15923 * of the state's write marks. That's what 'parent == state->parent' comparison
15924 * in mark_reg_read() is for.
15926 static int propagate_liveness(struct bpf_verifier_env *env,
15927 const struct bpf_verifier_state *vstate,
15928 struct bpf_verifier_state *vparent)
15930 struct bpf_reg_state *state_reg, *parent_reg;
15931 struct bpf_func_state *state, *parent;
15932 int i, frame, err = 0;
15934 if (vparent->curframe != vstate->curframe) {
15935 WARN(1, "propagate_live: parent frame %d current frame %d\n",
15936 vparent->curframe, vstate->curframe);
15939 /* Propagate read liveness of registers... */
15940 BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
15941 for (frame = 0; frame <= vstate->curframe; frame++) {
15942 parent = vparent->frame[frame];
15943 state = vstate->frame[frame];
15944 parent_reg = parent->regs;
15945 state_reg = state->regs;
15946 /* We don't need to worry about FP liveness, it's read-only */
15947 for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
15948 err = propagate_liveness_reg(env, &state_reg[i],
15952 if (err == REG_LIVE_READ64)
15953 mark_insn_zext(env, &parent_reg[i]);
15956 /* Propagate stack slots. */
15957 for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
15958 i < parent->allocated_stack / BPF_REG_SIZE; i++) {
15959 parent_reg = &parent->stack[i].spilled_ptr;
15960 state_reg = &state->stack[i].spilled_ptr;
15961 err = propagate_liveness_reg(env, state_reg,
15970 /* find precise scalars in the previous equivalent state and
15971 * propagate them into the current state
15973 static int propagate_precision(struct bpf_verifier_env *env,
15974 const struct bpf_verifier_state *old)
15976 struct bpf_reg_state *state_reg;
15977 struct bpf_func_state *state;
15978 int i, err = 0, fr;
15981 for (fr = old->curframe; fr >= 0; fr--) {
15982 state = old->frame[fr];
15983 state_reg = state->regs;
15985 for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
15986 if (state_reg->type != SCALAR_VALUE ||
15987 !state_reg->precise ||
15988 !(state_reg->live & REG_LIVE_READ))
15990 if (env->log.level & BPF_LOG_LEVEL2) {
15992 verbose(env, "frame %d: propagating r%d", fr, i);
15994 verbose(env, ",r%d", i);
15996 bt_set_frame_reg(&env->bt, fr, i);
16000 for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
16001 if (!is_spilled_reg(&state->stack[i]))
16003 state_reg = &state->stack[i].spilled_ptr;
16004 if (state_reg->type != SCALAR_VALUE ||
16005 !state_reg->precise ||
16006 !(state_reg->live & REG_LIVE_READ))
16008 if (env->log.level & BPF_LOG_LEVEL2) {
16010 verbose(env, "frame %d: propagating fp%d",
16011 fr, (-i - 1) * BPF_REG_SIZE);
16013 verbose(env, ",fp%d", (-i - 1) * BPF_REG_SIZE);
16015 bt_set_frame_slot(&env->bt, fr, i);
16019 verbose(env, "\n");
16022 err = mark_chain_precision_batch(env);
16029 static bool states_maybe_looping(struct bpf_verifier_state *old,
16030 struct bpf_verifier_state *cur)
16032 struct bpf_func_state *fold, *fcur;
16033 int i, fr = cur->curframe;
16035 if (old->curframe != fr)
16038 fold = old->frame[fr];
16039 fcur = cur->frame[fr];
16040 for (i = 0; i < MAX_BPF_REG; i++)
16041 if (memcmp(&fold->regs[i], &fcur->regs[i],
16042 offsetof(struct bpf_reg_state, parent)))
16047 static bool is_iter_next_insn(struct bpf_verifier_env *env, int insn_idx)
16049 return env->insn_aux_data[insn_idx].is_iter_next;
16052 /* is_state_visited() handles iter_next() (see process_iter_next_call() for
16053 * terminology) calls specially: as opposed to bounded BPF loops, it *expects*
16054 * states to match, which otherwise would look like an infinite loop. So while
16055 * iter_next() calls are taken care of, we still need to be careful and
16056 * prevent erroneous and too eager declaration of "ininite loop", when
16057 * iterators are involved.
16059 * Here's a situation in pseudo-BPF assembly form:
16061 * 0: again: ; set up iter_next() call args
16062 * 1: r1 = &it ; <CHECKPOINT HERE>
16063 * 2: call bpf_iter_num_next ; this is iter_next() call
16064 * 3: if r0 == 0 goto done
16065 * 4: ... something useful here ...
16066 * 5: goto again ; another iteration
16069 * 8: call bpf_iter_num_destroy ; clean up iter state
16072 * This is a typical loop. Let's assume that we have a prune point at 1:,
16073 * before we get to `call bpf_iter_num_next` (e.g., because of that `goto
16074 * again`, assuming other heuristics don't get in a way).
16076 * When we first time come to 1:, let's say we have some state X. We proceed
16077 * to 2:, fork states, enqueue ACTIVE, validate NULL case successfully, exit.
16078 * Now we come back to validate that forked ACTIVE state. We proceed through
16079 * 3-5, come to goto, jump to 1:. Let's assume our state didn't change, so we
16080 * are converging. But the problem is that we don't know that yet, as this
16081 * convergence has to happen at iter_next() call site only. So if nothing is
16082 * done, at 1: verifier will use bounded loop logic and declare infinite
16083 * looping (and would be *technically* correct, if not for iterator's
16084 * "eventual sticky NULL" contract, see process_iter_next_call()). But we
16085 * don't want that. So what we do in process_iter_next_call() when we go on
16086 * another ACTIVE iteration, we bump slot->iter.depth, to mark that it's
16087 * a different iteration. So when we suspect an infinite loop, we additionally
16088 * check if any of the *ACTIVE* iterator states depths differ. If yes, we
16089 * pretend we are not looping and wait for next iter_next() call.
16091 * This only applies to ACTIVE state. In DRAINED state we don't expect to
16092 * loop, because that would actually mean infinite loop, as DRAINED state is
16093 * "sticky", and so we'll keep returning into the same instruction with the
16094 * same state (at least in one of possible code paths).
16096 * This approach allows to keep infinite loop heuristic even in the face of
16097 * active iterator. E.g., C snippet below is and will be detected as
16098 * inifintely looping:
16100 * struct bpf_iter_num it;
16103 * bpf_iter_num_new(&it, 0, 10);
16104 * while ((p = bpf_iter_num_next(&t))) {
16106 * while (x--) {} // <<-- infinite loop here
16110 static bool iter_active_depths_differ(struct bpf_verifier_state *old, struct bpf_verifier_state *cur)
16112 struct bpf_reg_state *slot, *cur_slot;
16113 struct bpf_func_state *state;
16116 for (fr = old->curframe; fr >= 0; fr--) {
16117 state = old->frame[fr];
16118 for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
16119 if (state->stack[i].slot_type[0] != STACK_ITER)
16122 slot = &state->stack[i].spilled_ptr;
16123 if (slot->iter.state != BPF_ITER_STATE_ACTIVE)
16126 cur_slot = &cur->frame[fr]->stack[i].spilled_ptr;
16127 if (cur_slot->iter.depth != slot->iter.depth)
16134 static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
16136 struct bpf_verifier_state_list *new_sl;
16137 struct bpf_verifier_state_list *sl, **pprev;
16138 struct bpf_verifier_state *cur = env->cur_state, *new;
16139 int i, j, err, states_cnt = 0;
16140 bool force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx);
16141 bool add_new_state = force_new_state;
16143 /* bpf progs typically have pruning point every 4 instructions
16144 * http://vger.kernel.org/bpfconf2019.html#session-1
16145 * Do not add new state for future pruning if the verifier hasn't seen
16146 * at least 2 jumps and at least 8 instructions.
16147 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
16148 * In tests that amounts to up to 50% reduction into total verifier
16149 * memory consumption and 20% verifier time speedup.
16151 if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
16152 env->insn_processed - env->prev_insn_processed >= 8)
16153 add_new_state = true;
16155 pprev = explored_state(env, insn_idx);
16158 clean_live_states(env, insn_idx, cur);
16162 if (sl->state.insn_idx != insn_idx)
16165 if (sl->state.branches) {
16166 struct bpf_func_state *frame = sl->state.frame[sl->state.curframe];
16168 if (frame->in_async_callback_fn &&
16169 frame->async_entry_cnt != cur->frame[cur->curframe]->async_entry_cnt) {
16170 /* Different async_entry_cnt means that the verifier is
16171 * processing another entry into async callback.
16172 * Seeing the same state is not an indication of infinite
16173 * loop or infinite recursion.
16174 * But finding the same state doesn't mean that it's safe
16175 * to stop processing the current state. The previous state
16176 * hasn't yet reached bpf_exit, since state.branches > 0.
16177 * Checking in_async_callback_fn alone is not enough either.
16178 * Since the verifier still needs to catch infinite loops
16179 * inside async callbacks.
16181 goto skip_inf_loop_check;
16183 /* BPF open-coded iterators loop detection is special.
16184 * states_maybe_looping() logic is too simplistic in detecting
16185 * states that *might* be equivalent, because it doesn't know
16186 * about ID remapping, so don't even perform it.
16187 * See process_iter_next_call() and iter_active_depths_differ()
16188 * for overview of the logic. When current and one of parent
16189 * states are detected as equivalent, it's a good thing: we prove
16190 * convergence and can stop simulating further iterations.
16191 * It's safe to assume that iterator loop will finish, taking into
16192 * account iter_next() contract of eventually returning
16193 * sticky NULL result.
16195 if (is_iter_next_insn(env, insn_idx)) {
16196 if (states_equal(env, &sl->state, cur)) {
16197 struct bpf_func_state *cur_frame;
16198 struct bpf_reg_state *iter_state, *iter_reg;
16201 cur_frame = cur->frame[cur->curframe];
16202 /* btf_check_iter_kfuncs() enforces that
16203 * iter state pointer is always the first arg
16205 iter_reg = &cur_frame->regs[BPF_REG_1];
16206 /* current state is valid due to states_equal(),
16207 * so we can assume valid iter and reg state,
16208 * no need for extra (re-)validations
16210 spi = __get_spi(iter_reg->off + iter_reg->var_off.value);
16211 iter_state = &func(env, iter_reg)->stack[spi].spilled_ptr;
16212 if (iter_state->iter.state == BPF_ITER_STATE_ACTIVE)
16215 goto skip_inf_loop_check;
16217 /* attempt to detect infinite loop to avoid unnecessary doomed work */
16218 if (states_maybe_looping(&sl->state, cur) &&
16219 states_equal(env, &sl->state, cur) &&
16220 !iter_active_depths_differ(&sl->state, cur)) {
16221 verbose_linfo(env, insn_idx, "; ");
16222 verbose(env, "infinite loop detected at insn %d\n", insn_idx);
16225 /* if the verifier is processing a loop, avoid adding new state
16226 * too often, since different loop iterations have distinct
16227 * states and may not help future pruning.
16228 * This threshold shouldn't be too low to make sure that
16229 * a loop with large bound will be rejected quickly.
16230 * The most abusive loop will be:
16232 * if r1 < 1000000 goto pc-2
16233 * 1M insn_procssed limit / 100 == 10k peak states.
16234 * This threshold shouldn't be too high either, since states
16235 * at the end of the loop are likely to be useful in pruning.
16237 skip_inf_loop_check:
16238 if (!force_new_state &&
16239 env->jmps_processed - env->prev_jmps_processed < 20 &&
16240 env->insn_processed - env->prev_insn_processed < 100)
16241 add_new_state = false;
16244 if (states_equal(env, &sl->state, cur)) {
16247 /* reached equivalent register/stack state,
16248 * prune the search.
16249 * Registers read by the continuation are read by us.
16250 * If we have any write marks in env->cur_state, they
16251 * will prevent corresponding reads in the continuation
16252 * from reaching our parent (an explored_state). Our
16253 * own state will get the read marks recorded, but
16254 * they'll be immediately forgotten as we're pruning
16255 * this state and will pop a new one.
16257 err = propagate_liveness(env, &sl->state, cur);
16259 /* if previous state reached the exit with precision and
16260 * current state is equivalent to it (except precsion marks)
16261 * the precision needs to be propagated back in
16262 * the current state.
16264 err = err ? : push_jmp_history(env, cur);
16265 err = err ? : propagate_precision(env, &sl->state);
16271 /* when new state is not going to be added do not increase miss count.
16272 * Otherwise several loop iterations will remove the state
16273 * recorded earlier. The goal of these heuristics is to have
16274 * states from some iterations of the loop (some in the beginning
16275 * and some at the end) to help pruning.
16279 /* heuristic to determine whether this state is beneficial
16280 * to keep checking from state equivalence point of view.
16281 * Higher numbers increase max_states_per_insn and verification time,
16282 * but do not meaningfully decrease insn_processed.
16284 if (sl->miss_cnt > sl->hit_cnt * 3 + 3) {
16285 /* the state is unlikely to be useful. Remove it to
16286 * speed up verification
16289 if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) {
16290 u32 br = sl->state.branches;
16293 "BUG live_done but branches_to_explore %d\n",
16295 free_verifier_state(&sl->state, false);
16297 env->peak_states--;
16299 /* cannot free this state, since parentage chain may
16300 * walk it later. Add it for free_list instead to
16301 * be freed at the end of verification
16303 sl->next = env->free_list;
16304 env->free_list = sl;
16314 if (env->max_states_per_insn < states_cnt)
16315 env->max_states_per_insn = states_cnt;
16317 if (!env->bpf_capable && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
16320 if (!add_new_state)
16323 /* There were no equivalent states, remember the current one.
16324 * Technically the current state is not proven to be safe yet,
16325 * but it will either reach outer most bpf_exit (which means it's safe)
16326 * or it will be rejected. When there are no loops the verifier won't be
16327 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
16328 * again on the way to bpf_exit.
16329 * When looping the sl->state.branches will be > 0 and this state
16330 * will not be considered for equivalence until branches == 0.
16332 new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
16335 env->total_states++;
16336 env->peak_states++;
16337 env->prev_jmps_processed = env->jmps_processed;
16338 env->prev_insn_processed = env->insn_processed;
16340 /* forget precise markings we inherited, see __mark_chain_precision */
16341 if (env->bpf_capable)
16342 mark_all_scalars_imprecise(env, cur);
16344 /* add new state to the head of linked list */
16345 new = &new_sl->state;
16346 err = copy_verifier_state(new, cur);
16348 free_verifier_state(new, false);
16352 new->insn_idx = insn_idx;
16353 WARN_ONCE(new->branches != 1,
16354 "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);
16357 cur->first_insn_idx = insn_idx;
16358 clear_jmp_history(cur);
16359 new_sl->next = *explored_state(env, insn_idx);
16360 *explored_state(env, insn_idx) = new_sl;
16361 /* connect new state to parentage chain. Current frame needs all
16362 * registers connected. Only r6 - r9 of the callers are alive (pushed
16363 * to the stack implicitly by JITs) so in callers' frames connect just
16364 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
16365 * the state of the call instruction (with WRITTEN set), and r0 comes
16366 * from callee with its full parentage chain, anyway.
16368 /* clear write marks in current state: the writes we did are not writes
16369 * our child did, so they don't screen off its reads from us.
16370 * (There are no read marks in current state, because reads always mark
16371 * their parent and current state never has children yet. Only
16372 * explored_states can get read marks.)
16374 for (j = 0; j <= cur->curframe; j++) {
16375 for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
16376 cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
16377 for (i = 0; i < BPF_REG_FP; i++)
16378 cur->frame[j]->regs[i].live = REG_LIVE_NONE;
16381 /* all stack frames are accessible from callee, clear them all */
16382 for (j = 0; j <= cur->curframe; j++) {
16383 struct bpf_func_state *frame = cur->frame[j];
16384 struct bpf_func_state *newframe = new->frame[j];
16386 for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
16387 frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
16388 frame->stack[i].spilled_ptr.parent =
16389 &newframe->stack[i].spilled_ptr;
16395 /* Return true if it's OK to have the same insn return a different type. */
16396 static bool reg_type_mismatch_ok(enum bpf_reg_type type)
16398 switch (base_type(type)) {
16400 case PTR_TO_SOCKET:
16401 case PTR_TO_SOCK_COMMON:
16402 case PTR_TO_TCP_SOCK:
16403 case PTR_TO_XDP_SOCK:
16404 case PTR_TO_BTF_ID:
16411 /* If an instruction was previously used with particular pointer types, then we
16412 * need to be careful to avoid cases such as the below, where it may be ok
16413 * for one branch accessing the pointer, but not ok for the other branch:
16418 * R1 = some_other_valid_ptr;
16421 * R2 = *(u32 *)(R1 + 0);
16423 static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
16425 return src != prev && (!reg_type_mismatch_ok(src) ||
16426 !reg_type_mismatch_ok(prev));
16429 static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type type,
16430 bool allow_trust_missmatch)
16432 enum bpf_reg_type *prev_type = &env->insn_aux_data[env->insn_idx].ptr_type;
16434 if (*prev_type == NOT_INIT) {
16435 /* Saw a valid insn
16436 * dst_reg = *(u32 *)(src_reg + off)
16437 * save type to validate intersecting paths
16440 } else if (reg_type_mismatch(type, *prev_type)) {
16441 /* Abuser program is trying to use the same insn
16442 * dst_reg = *(u32*) (src_reg + off)
16443 * with different pointer types:
16444 * src_reg == ctx in one branch and
16445 * src_reg == stack|map in some other branch.
16448 if (allow_trust_missmatch &&
16449 base_type(type) == PTR_TO_BTF_ID &&
16450 base_type(*prev_type) == PTR_TO_BTF_ID) {
16452 * Have to support a use case when one path through
16453 * the program yields TRUSTED pointer while another
16454 * is UNTRUSTED. Fallback to UNTRUSTED to generate
16455 * BPF_PROBE_MEM/BPF_PROBE_MEMSX.
16457 *prev_type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
16459 verbose(env, "same insn cannot be used with different pointers\n");
16467 static int do_check(struct bpf_verifier_env *env)
16469 bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
16470 struct bpf_verifier_state *state = env->cur_state;
16471 struct bpf_insn *insns = env->prog->insnsi;
16472 struct bpf_reg_state *regs;
16473 int insn_cnt = env->prog->len;
16474 bool do_print_state = false;
16475 int prev_insn_idx = -1;
16478 struct bpf_insn *insn;
16482 env->prev_insn_idx = prev_insn_idx;
16483 if (env->insn_idx >= insn_cnt) {
16484 verbose(env, "invalid insn idx %d insn_cnt %d\n",
16485 env->insn_idx, insn_cnt);
16489 insn = &insns[env->insn_idx];
16490 class = BPF_CLASS(insn->code);
16492 if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
16494 "BPF program is too large. Processed %d insn\n",
16495 env->insn_processed);
16499 state->last_insn_idx = env->prev_insn_idx;
16501 if (is_prune_point(env, env->insn_idx)) {
16502 err = is_state_visited(env, env->insn_idx);
16506 /* found equivalent state, can prune the search */
16507 if (env->log.level & BPF_LOG_LEVEL) {
16508 if (do_print_state)
16509 verbose(env, "\nfrom %d to %d%s: safe\n",
16510 env->prev_insn_idx, env->insn_idx,
16511 env->cur_state->speculative ?
16512 " (speculative execution)" : "");
16514 verbose(env, "%d: safe\n", env->insn_idx);
16516 goto process_bpf_exit;
16520 if (is_jmp_point(env, env->insn_idx)) {
16521 err = push_jmp_history(env, state);
16526 if (signal_pending(current))
16529 if (need_resched())
16532 if (env->log.level & BPF_LOG_LEVEL2 && do_print_state) {
16533 verbose(env, "\nfrom %d to %d%s:",
16534 env->prev_insn_idx, env->insn_idx,
16535 env->cur_state->speculative ?
16536 " (speculative execution)" : "");
16537 print_verifier_state(env, state->frame[state->curframe], true);
16538 do_print_state = false;
16541 if (env->log.level & BPF_LOG_LEVEL) {
16542 const struct bpf_insn_cbs cbs = {
16543 .cb_call = disasm_kfunc_name,
16544 .cb_print = verbose,
16545 .private_data = env,
16548 if (verifier_state_scratched(env))
16549 print_insn_state(env, state->frame[state->curframe]);
16551 verbose_linfo(env, env->insn_idx, "; ");
16552 env->prev_log_pos = env->log.end_pos;
16553 verbose(env, "%d: ", env->insn_idx);
16554 print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
16555 env->prev_insn_print_pos = env->log.end_pos - env->prev_log_pos;
16556 env->prev_log_pos = env->log.end_pos;
16559 if (bpf_prog_is_offloaded(env->prog->aux)) {
16560 err = bpf_prog_offload_verify_insn(env, env->insn_idx,
16561 env->prev_insn_idx);
16566 regs = cur_regs(env);
16567 sanitize_mark_insn_seen(env);
16568 prev_insn_idx = env->insn_idx;
16570 if (class == BPF_ALU || class == BPF_ALU64) {
16571 err = check_alu_op(env, insn);
16575 } else if (class == BPF_LDX) {
16576 enum bpf_reg_type src_reg_type;
16578 /* check for reserved fields is already done */
16580 /* check src operand */
16581 err = check_reg_arg(env, insn->src_reg, SRC_OP);
16585 err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
16589 src_reg_type = regs[insn->src_reg].type;
16591 /* check that memory (src_reg + off) is readable,
16592 * the state of dst_reg will be updated by this func
16594 err = check_mem_access(env, env->insn_idx, insn->src_reg,
16595 insn->off, BPF_SIZE(insn->code),
16596 BPF_READ, insn->dst_reg, false,
16597 BPF_MODE(insn->code) == BPF_MEMSX);
16601 err = save_aux_ptr_type(env, src_reg_type, true);
16604 } else if (class == BPF_STX) {
16605 enum bpf_reg_type dst_reg_type;
16607 if (BPF_MODE(insn->code) == BPF_ATOMIC) {
16608 err = check_atomic(env, env->insn_idx, insn);
16615 if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) {
16616 verbose(env, "BPF_STX uses reserved fields\n");
16620 /* check src1 operand */
16621 err = check_reg_arg(env, insn->src_reg, SRC_OP);
16624 /* check src2 operand */
16625 err = check_reg_arg(env, insn->dst_reg, SRC_OP);
16629 dst_reg_type = regs[insn->dst_reg].type;
16631 /* check that memory (dst_reg + off) is writeable */
16632 err = check_mem_access(env, env->insn_idx, insn->dst_reg,
16633 insn->off, BPF_SIZE(insn->code),
16634 BPF_WRITE, insn->src_reg, false, false);
16638 err = save_aux_ptr_type(env, dst_reg_type, false);
16641 } else if (class == BPF_ST) {
16642 enum bpf_reg_type dst_reg_type;
16644 if (BPF_MODE(insn->code) != BPF_MEM ||
16645 insn->src_reg != BPF_REG_0) {
16646 verbose(env, "BPF_ST uses reserved fields\n");
16649 /* check src operand */
16650 err = check_reg_arg(env, insn->dst_reg, SRC_OP);
16654 dst_reg_type = regs[insn->dst_reg].type;
16656 /* check that memory (dst_reg + off) is writeable */
16657 err = check_mem_access(env, env->insn_idx, insn->dst_reg,
16658 insn->off, BPF_SIZE(insn->code),
16659 BPF_WRITE, -1, false, false);
16663 err = save_aux_ptr_type(env, dst_reg_type, false);
16666 } else if (class == BPF_JMP || class == BPF_JMP32) {
16667 u8 opcode = BPF_OP(insn->code);
16669 env->jmps_processed++;
16670 if (opcode == BPF_CALL) {
16671 if (BPF_SRC(insn->code) != BPF_K ||
16672 (insn->src_reg != BPF_PSEUDO_KFUNC_CALL
16673 && insn->off != 0) ||
16674 (insn->src_reg != BPF_REG_0 &&
16675 insn->src_reg != BPF_PSEUDO_CALL &&
16676 insn->src_reg != BPF_PSEUDO_KFUNC_CALL) ||
16677 insn->dst_reg != BPF_REG_0 ||
16678 class == BPF_JMP32) {
16679 verbose(env, "BPF_CALL uses reserved fields\n");
16683 if (env->cur_state->active_lock.ptr) {
16684 if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) ||
16685 (insn->src_reg == BPF_PSEUDO_CALL) ||
16686 (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
16687 (insn->off != 0 || !is_bpf_graph_api_kfunc(insn->imm)))) {
16688 verbose(env, "function calls are not allowed while holding a lock\n");
16692 if (insn->src_reg == BPF_PSEUDO_CALL)
16693 err = check_func_call(env, insn, &env->insn_idx);
16694 else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
16695 err = check_kfunc_call(env, insn, &env->insn_idx);
16697 err = check_helper_call(env, insn, &env->insn_idx);
16701 mark_reg_scratched(env, BPF_REG_0);
16702 } else if (opcode == BPF_JA) {
16703 if (BPF_SRC(insn->code) != BPF_K ||
16704 insn->src_reg != BPF_REG_0 ||
16705 insn->dst_reg != BPF_REG_0 ||
16706 (class == BPF_JMP && insn->imm != 0) ||
16707 (class == BPF_JMP32 && insn->off != 0)) {
16708 verbose(env, "BPF_JA uses reserved fields\n");
16712 if (class == BPF_JMP)
16713 env->insn_idx += insn->off + 1;
16715 env->insn_idx += insn->imm + 1;
16718 } else if (opcode == BPF_EXIT) {
16719 if (BPF_SRC(insn->code) != BPF_K ||
16721 insn->src_reg != BPF_REG_0 ||
16722 insn->dst_reg != BPF_REG_0 ||
16723 class == BPF_JMP32) {
16724 verbose(env, "BPF_EXIT uses reserved fields\n");
16728 if (env->cur_state->active_lock.ptr &&
16729 !in_rbtree_lock_required_cb(env)) {
16730 verbose(env, "bpf_spin_unlock is missing\n");
16734 if (env->cur_state->active_rcu_lock &&
16735 !in_rbtree_lock_required_cb(env)) {
16736 verbose(env, "bpf_rcu_read_unlock is missing\n");
16740 /* We must do check_reference_leak here before
16741 * prepare_func_exit to handle the case when
16742 * state->curframe > 0, it may be a callback
16743 * function, for which reference_state must
16744 * match caller reference state when it exits.
16746 err = check_reference_leak(env);
16750 if (state->curframe) {
16751 /* exit from nested function */
16752 err = prepare_func_exit(env, &env->insn_idx);
16755 do_print_state = true;
16759 err = check_return_code(env);
16763 mark_verifier_state_scratched(env);
16764 update_branch_counts(env, env->cur_state);
16765 err = pop_stack(env, &prev_insn_idx,
16766 &env->insn_idx, pop_log);
16768 if (err != -ENOENT)
16772 do_print_state = true;
16776 err = check_cond_jmp_op(env, insn, &env->insn_idx);
16780 } else if (class == BPF_LD) {
16781 u8 mode = BPF_MODE(insn->code);
16783 if (mode == BPF_ABS || mode == BPF_IND) {
16784 err = check_ld_abs(env, insn);
16788 } else if (mode == BPF_IMM) {
16789 err = check_ld_imm(env, insn);
16794 sanitize_mark_insn_seen(env);
16796 verbose(env, "invalid BPF_LD mode\n");
16800 verbose(env, "unknown insn class %d\n", class);
16810 static int find_btf_percpu_datasec(struct btf *btf)
16812 const struct btf_type *t;
16817 * Both vmlinux and module each have their own ".data..percpu"
16818 * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
16819 * types to look at only module's own BTF types.
16821 n = btf_nr_types(btf);
16822 if (btf_is_module(btf))
16823 i = btf_nr_types(btf_vmlinux);
16827 for(; i < n; i++) {
16828 t = btf_type_by_id(btf, i);
16829 if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
16832 tname = btf_name_by_offset(btf, t->name_off);
16833 if (!strcmp(tname, ".data..percpu"))
16840 /* replace pseudo btf_id with kernel symbol address */
16841 static int check_pseudo_btf_id(struct bpf_verifier_env *env,
16842 struct bpf_insn *insn,
16843 struct bpf_insn_aux_data *aux)
16845 const struct btf_var_secinfo *vsi;
16846 const struct btf_type *datasec;
16847 struct btf_mod_pair *btf_mod;
16848 const struct btf_type *t;
16849 const char *sym_name;
16850 bool percpu = false;
16851 u32 type, id = insn->imm;
16855 int i, btf_fd, err;
16857 btf_fd = insn[1].imm;
16859 btf = btf_get_by_fd(btf_fd);
16861 verbose(env, "invalid module BTF object FD specified.\n");
16865 if (!btf_vmlinux) {
16866 verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
16873 t = btf_type_by_id(btf, id);
16875 verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
16880 if (!btf_type_is_var(t) && !btf_type_is_func(t)) {
16881 verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR or KIND_FUNC\n", id);
16886 sym_name = btf_name_by_offset(btf, t->name_off);
16887 addr = kallsyms_lookup_name(sym_name);
16889 verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
16894 insn[0].imm = (u32)addr;
16895 insn[1].imm = addr >> 32;
16897 if (btf_type_is_func(t)) {
16898 aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
16899 aux->btf_var.mem_size = 0;
16903 datasec_id = find_btf_percpu_datasec(btf);
16904 if (datasec_id > 0) {
16905 datasec = btf_type_by_id(btf, datasec_id);
16906 for_each_vsi(i, datasec, vsi) {
16907 if (vsi->type == id) {
16915 t = btf_type_skip_modifiers(btf, type, NULL);
16917 aux->btf_var.reg_type = PTR_TO_BTF_ID | MEM_PERCPU;
16918 aux->btf_var.btf = btf;
16919 aux->btf_var.btf_id = type;
16920 } else if (!btf_type_is_struct(t)) {
16921 const struct btf_type *ret;
16925 /* resolve the type size of ksym. */
16926 ret = btf_resolve_size(btf, t, &tsize);
16928 tname = btf_name_by_offset(btf, t->name_off);
16929 verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n",
16930 tname, PTR_ERR(ret));
16934 aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
16935 aux->btf_var.mem_size = tsize;
16937 aux->btf_var.reg_type = PTR_TO_BTF_ID;
16938 aux->btf_var.btf = btf;
16939 aux->btf_var.btf_id = type;
16942 /* check whether we recorded this BTF (and maybe module) already */
16943 for (i = 0; i < env->used_btf_cnt; i++) {
16944 if (env->used_btfs[i].btf == btf) {
16950 if (env->used_btf_cnt >= MAX_USED_BTFS) {
16955 btf_mod = &env->used_btfs[env->used_btf_cnt];
16956 btf_mod->btf = btf;
16957 btf_mod->module = NULL;
16959 /* if we reference variables from kernel module, bump its refcount */
16960 if (btf_is_module(btf)) {
16961 btf_mod->module = btf_try_get_module(btf);
16962 if (!btf_mod->module) {
16968 env->used_btf_cnt++;
16976 static bool is_tracing_prog_type(enum bpf_prog_type type)
16979 case BPF_PROG_TYPE_KPROBE:
16980 case BPF_PROG_TYPE_TRACEPOINT:
16981 case BPF_PROG_TYPE_PERF_EVENT:
16982 case BPF_PROG_TYPE_RAW_TRACEPOINT:
16983 case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
16990 static int check_map_prog_compatibility(struct bpf_verifier_env *env,
16991 struct bpf_map *map,
16992 struct bpf_prog *prog)
16995 enum bpf_prog_type prog_type = resolve_prog_type(prog);
16997 if (btf_record_has_field(map->record, BPF_LIST_HEAD) ||
16998 btf_record_has_field(map->record, BPF_RB_ROOT)) {
16999 if (is_tracing_prog_type(prog_type)) {
17000 verbose(env, "tracing progs cannot use bpf_{list_head,rb_root} yet\n");
17005 if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
17006 if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
17007 verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
17011 if (is_tracing_prog_type(prog_type)) {
17012 verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
17017 if (btf_record_has_field(map->record, BPF_TIMER)) {
17018 if (is_tracing_prog_type(prog_type)) {
17019 verbose(env, "tracing progs cannot use bpf_timer yet\n");
17024 if ((bpf_prog_is_offloaded(prog->aux) || bpf_map_is_offloaded(map)) &&
17025 !bpf_offload_prog_map_match(prog, map)) {
17026 verbose(env, "offload device mismatch between prog and map\n");
17030 if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
17031 verbose(env, "bpf_struct_ops map cannot be used in prog\n");
17035 if (prog->aux->sleepable)
17036 switch (map->map_type) {
17037 case BPF_MAP_TYPE_HASH:
17038 case BPF_MAP_TYPE_LRU_HASH:
17039 case BPF_MAP_TYPE_ARRAY:
17040 case BPF_MAP_TYPE_PERCPU_HASH:
17041 case BPF_MAP_TYPE_PERCPU_ARRAY:
17042 case BPF_MAP_TYPE_LRU_PERCPU_HASH:
17043 case BPF_MAP_TYPE_ARRAY_OF_MAPS:
17044 case BPF_MAP_TYPE_HASH_OF_MAPS:
17045 case BPF_MAP_TYPE_RINGBUF:
17046 case BPF_MAP_TYPE_USER_RINGBUF:
17047 case BPF_MAP_TYPE_INODE_STORAGE:
17048 case BPF_MAP_TYPE_SK_STORAGE:
17049 case BPF_MAP_TYPE_TASK_STORAGE:
17050 case BPF_MAP_TYPE_CGRP_STORAGE:
17054 "Sleepable programs can only use array, hash, ringbuf and local storage maps\n");
17061 static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
17063 return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
17064 map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
17067 /* find and rewrite pseudo imm in ld_imm64 instructions:
17069 * 1. if it accesses map FD, replace it with actual map pointer.
17070 * 2. if it accesses btf_id of a VAR, replace it with pointer to the var.
17072 * NOTE: btf_vmlinux is required for converting pseudo btf_id.
17074 static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
17076 struct bpf_insn *insn = env->prog->insnsi;
17077 int insn_cnt = env->prog->len;
17080 err = bpf_prog_calc_tag(env->prog);
17084 for (i = 0; i < insn_cnt; i++, insn++) {
17085 if (BPF_CLASS(insn->code) == BPF_LDX &&
17086 ((BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) ||
17088 verbose(env, "BPF_LDX uses reserved fields\n");
17092 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
17093 struct bpf_insn_aux_data *aux;
17094 struct bpf_map *map;
17099 if (i == insn_cnt - 1 || insn[1].code != 0 ||
17100 insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
17101 insn[1].off != 0) {
17102 verbose(env, "invalid bpf_ld_imm64 insn\n");
17106 if (insn[0].src_reg == 0)
17107 /* valid generic load 64-bit imm */
17110 if (insn[0].src_reg == BPF_PSEUDO_BTF_ID) {
17111 aux = &env->insn_aux_data[i];
17112 err = check_pseudo_btf_id(env, insn, aux);
17118 if (insn[0].src_reg == BPF_PSEUDO_FUNC) {
17119 aux = &env->insn_aux_data[i];
17120 aux->ptr_type = PTR_TO_FUNC;
17124 /* In final convert_pseudo_ld_imm64() step, this is
17125 * converted into regular 64-bit imm load insn.
17127 switch (insn[0].src_reg) {
17128 case BPF_PSEUDO_MAP_VALUE:
17129 case BPF_PSEUDO_MAP_IDX_VALUE:
17131 case BPF_PSEUDO_MAP_FD:
17132 case BPF_PSEUDO_MAP_IDX:
17133 if (insn[1].imm == 0)
17137 verbose(env, "unrecognized bpf_ld_imm64 insn\n");
17141 switch (insn[0].src_reg) {
17142 case BPF_PSEUDO_MAP_IDX_VALUE:
17143 case BPF_PSEUDO_MAP_IDX:
17144 if (bpfptr_is_null(env->fd_array)) {
17145 verbose(env, "fd_idx without fd_array is invalid\n");
17148 if (copy_from_bpfptr_offset(&fd, env->fd_array,
17149 insn[0].imm * sizeof(fd),
17159 map = __bpf_map_get(f);
17161 verbose(env, "fd %d is not pointing to valid bpf_map\n",
17163 return PTR_ERR(map);
17166 err = check_map_prog_compatibility(env, map, env->prog);
17172 aux = &env->insn_aux_data[i];
17173 if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
17174 insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
17175 addr = (unsigned long)map;
17177 u32 off = insn[1].imm;
17179 if (off >= BPF_MAX_VAR_OFF) {
17180 verbose(env, "direct value offset of %u is not allowed\n", off);
17185 if (!map->ops->map_direct_value_addr) {
17186 verbose(env, "no direct value access support for this map type\n");
17191 err = map->ops->map_direct_value_addr(map, &addr, off);
17193 verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
17194 map->value_size, off);
17199 aux->map_off = off;
17203 insn[0].imm = (u32)addr;
17204 insn[1].imm = addr >> 32;
17206 /* check whether we recorded this map already */
17207 for (j = 0; j < env->used_map_cnt; j++) {
17208 if (env->used_maps[j] == map) {
17209 aux->map_index = j;
17215 if (env->used_map_cnt >= MAX_USED_MAPS) {
17220 /* hold the map. If the program is rejected by verifier,
17221 * the map will be released by release_maps() or it
17222 * will be used by the valid program until it's unloaded
17223 * and all maps are released in free_used_maps()
17227 aux->map_index = env->used_map_cnt;
17228 env->used_maps[env->used_map_cnt++] = map;
17230 if (bpf_map_is_cgroup_storage(map) &&
17231 bpf_cgroup_storage_assign(env->prog->aux, map)) {
17232 verbose(env, "only one cgroup storage of each type is allowed\n");
17244 /* Basic sanity check before we invest more work here. */
17245 if (!bpf_opcode_in_insntable(insn->code)) {
17246 verbose(env, "unknown opcode %02x\n", insn->code);
17251 /* now all pseudo BPF_LD_IMM64 instructions load valid
17252 * 'struct bpf_map *' into a register instead of user map_fd.
17253 * These pointers will be used later by verifier to validate map access.
17258 /* drop refcnt of maps used by the rejected program */
17259 static void release_maps(struct bpf_verifier_env *env)
17261 __bpf_free_used_maps(env->prog->aux, env->used_maps,
17262 env->used_map_cnt);
17265 /* drop refcnt of maps used by the rejected program */
17266 static void release_btfs(struct bpf_verifier_env *env)
17268 __bpf_free_used_btfs(env->prog->aux, env->used_btfs,
17269 env->used_btf_cnt);
17272 /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
17273 static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
17275 struct bpf_insn *insn = env->prog->insnsi;
17276 int insn_cnt = env->prog->len;
17279 for (i = 0; i < insn_cnt; i++, insn++) {
17280 if (insn->code != (BPF_LD | BPF_IMM | BPF_DW))
17282 if (insn->src_reg == BPF_PSEUDO_FUNC)
17288 /* single env->prog->insni[off] instruction was replaced with the range
17289 * insni[off, off + cnt). Adjust corresponding insn_aux_data by copying
17290 * [0, off) and [off, end) to new locations, so the patched range stays zero
17292 static void adjust_insn_aux_data(struct bpf_verifier_env *env,
17293 struct bpf_insn_aux_data *new_data,
17294 struct bpf_prog *new_prog, u32 off, u32 cnt)
17296 struct bpf_insn_aux_data *old_data = env->insn_aux_data;
17297 struct bpf_insn *insn = new_prog->insnsi;
17298 u32 old_seen = old_data[off].seen;
17302 /* aux info at OFF always needs adjustment, no matter fast path
17303 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
17304 * original insn at old prog.
17306 old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);
17310 prog_len = new_prog->len;
17312 memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
17313 memcpy(new_data + off + cnt - 1, old_data + off,
17314 sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
17315 for (i = off; i < off + cnt - 1; i++) {
17316 /* Expand insni[off]'s seen count to the patched range. */
17317 new_data[i].seen = old_seen;
17318 new_data[i].zext_dst = insn_has_def32(env, insn + i);
17320 env->insn_aux_data = new_data;
17324 static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
17330 /* NOTE: fake 'exit' subprog should be updated as well. */
17331 for (i = 0; i <= env->subprog_cnt; i++) {
17332 if (env->subprog_info[i].start <= off)
17334 env->subprog_info[i].start += len - 1;
17338 static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len)
17340 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
17341 int i, sz = prog->aux->size_poke_tab;
17342 struct bpf_jit_poke_descriptor *desc;
17344 for (i = 0; i < sz; i++) {
17346 if (desc->insn_idx <= off)
17348 desc->insn_idx += len - 1;
17352 static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
17353 const struct bpf_insn *patch, u32 len)
17355 struct bpf_prog *new_prog;
17356 struct bpf_insn_aux_data *new_data = NULL;
17359 new_data = vzalloc(array_size(env->prog->len + len - 1,
17360 sizeof(struct bpf_insn_aux_data)));
17365 new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
17366 if (IS_ERR(new_prog)) {
17367 if (PTR_ERR(new_prog) == -ERANGE)
17369 "insn %d cannot be patched due to 16-bit range\n",
17370 env->insn_aux_data[off].orig_idx);
17374 adjust_insn_aux_data(env, new_data, new_prog, off, len);
17375 adjust_subprog_starts(env, off, len);
17376 adjust_poke_descs(new_prog, off, len);
17380 static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
17385 /* find first prog starting at or after off (first to remove) */
17386 for (i = 0; i < env->subprog_cnt; i++)
17387 if (env->subprog_info[i].start >= off)
17389 /* find first prog starting at or after off + cnt (first to stay) */
17390 for (j = i; j < env->subprog_cnt; j++)
17391 if (env->subprog_info[j].start >= off + cnt)
17393 /* if j doesn't start exactly at off + cnt, we are just removing
17394 * the front of previous prog
17396 if (env->subprog_info[j].start != off + cnt)
17400 struct bpf_prog_aux *aux = env->prog->aux;
17403 /* move fake 'exit' subprog as well */
17404 move = env->subprog_cnt + 1 - j;
17406 memmove(env->subprog_info + i,
17407 env->subprog_info + j,
17408 sizeof(*env->subprog_info) * move);
17409 env->subprog_cnt -= j - i;
17411 /* remove func_info */
17412 if (aux->func_info) {
17413 move = aux->func_info_cnt - j;
17415 memmove(aux->func_info + i,
17416 aux->func_info + j,
17417 sizeof(*aux->func_info) * move);
17418 aux->func_info_cnt -= j - i;
17419 /* func_info->insn_off is set after all code rewrites,
17420 * in adjust_btf_func() - no need to adjust
17424 /* convert i from "first prog to remove" to "first to adjust" */
17425 if (env->subprog_info[i].start == off)
17429 /* update fake 'exit' subprog as well */
17430 for (; i <= env->subprog_cnt; i++)
17431 env->subprog_info[i].start -= cnt;
17436 static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
17439 struct bpf_prog *prog = env->prog;
17440 u32 i, l_off, l_cnt, nr_linfo;
17441 struct bpf_line_info *linfo;
17443 nr_linfo = prog->aux->nr_linfo;
17447 linfo = prog->aux->linfo;
17449 /* find first line info to remove, count lines to be removed */
17450 for (i = 0; i < nr_linfo; i++)
17451 if (linfo[i].insn_off >= off)
17456 for (; i < nr_linfo; i++)
17457 if (linfo[i].insn_off < off + cnt)
17462 /* First live insn doesn't match first live linfo, it needs to "inherit"
17463 * last removed linfo. prog is already modified, so prog->len == off
17464 * means no live instructions after (tail of the program was removed).
17466 if (prog->len != off && l_cnt &&
17467 (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
17469 linfo[--i].insn_off = off + cnt;
17472 /* remove the line info which refer to the removed instructions */
17474 memmove(linfo + l_off, linfo + i,
17475 sizeof(*linfo) * (nr_linfo - i));
17477 prog->aux->nr_linfo -= l_cnt;
17478 nr_linfo = prog->aux->nr_linfo;
17481 /* pull all linfo[i].insn_off >= off + cnt in by cnt */
17482 for (i = l_off; i < nr_linfo; i++)
17483 linfo[i].insn_off -= cnt;
17485 /* fix up all subprogs (incl. 'exit') which start >= off */
17486 for (i = 0; i <= env->subprog_cnt; i++)
17487 if (env->subprog_info[i].linfo_idx > l_off) {
17488 /* program may have started in the removed region but
17489 * may not be fully removed
17491 if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
17492 env->subprog_info[i].linfo_idx -= l_cnt;
17494 env->subprog_info[i].linfo_idx = l_off;
17500 static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
17502 struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
17503 unsigned int orig_prog_len = env->prog->len;
17506 if (bpf_prog_is_offloaded(env->prog->aux))
17507 bpf_prog_offload_remove_insns(env, off, cnt);
17509 err = bpf_remove_insns(env->prog, off, cnt);
17513 err = adjust_subprog_starts_after_remove(env, off, cnt);
17517 err = bpf_adj_linfo_after_remove(env, off, cnt);
17521 memmove(aux_data + off, aux_data + off + cnt,
17522 sizeof(*aux_data) * (orig_prog_len - off - cnt));
17527 /* The verifier does more data flow analysis than llvm and will not
17528 * explore branches that are dead at run time. Malicious programs can
17529 * have dead code too. Therefore replace all dead at-run-time code
17532 * Just nops are not optimal, e.g. if they would sit at the end of the
17533 * program and through another bug we would manage to jump there, then
17534 * we'd execute beyond program memory otherwise. Returning exception
17535 * code also wouldn't work since we can have subprogs where the dead
17536 * code could be located.
17538 static void sanitize_dead_code(struct bpf_verifier_env *env)
17540 struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
17541 struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1);
17542 struct bpf_insn *insn = env->prog->insnsi;
17543 const int insn_cnt = env->prog->len;
17546 for (i = 0; i < insn_cnt; i++) {
17547 if (aux_data[i].seen)
17549 memcpy(insn + i, &trap, sizeof(trap));
17550 aux_data[i].zext_dst = false;
17554 static bool insn_is_cond_jump(u8 code)
17559 if (BPF_CLASS(code) == BPF_JMP32)
17560 return op != BPF_JA;
17562 if (BPF_CLASS(code) != BPF_JMP)
17565 return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
17568 static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
17570 struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
17571 struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
17572 struct bpf_insn *insn = env->prog->insnsi;
17573 const int insn_cnt = env->prog->len;
17576 for (i = 0; i < insn_cnt; i++, insn++) {
17577 if (!insn_is_cond_jump(insn->code))
17580 if (!aux_data[i + 1].seen)
17581 ja.off = insn->off;
17582 else if (!aux_data[i + 1 + insn->off].seen)
17587 if (bpf_prog_is_offloaded(env->prog->aux))
17588 bpf_prog_offload_replace_insn(env, i, &ja);
17590 memcpy(insn, &ja, sizeof(ja));
17594 static int opt_remove_dead_code(struct bpf_verifier_env *env)
17596 struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
17597 int insn_cnt = env->prog->len;
17600 for (i = 0; i < insn_cnt; i++) {
17604 while (i + j < insn_cnt && !aux_data[i + j].seen)
17609 err = verifier_remove_insns(env, i, j);
17612 insn_cnt = env->prog->len;
17618 static int opt_remove_nops(struct bpf_verifier_env *env)
17620 const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
17621 struct bpf_insn *insn = env->prog->insnsi;
17622 int insn_cnt = env->prog->len;
17625 for (i = 0; i < insn_cnt; i++) {
17626 if (memcmp(&insn[i], &ja, sizeof(ja)))
17629 err = verifier_remove_insns(env, i, 1);
17639 static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
17640 const union bpf_attr *attr)
17642 struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
17643 struct bpf_insn_aux_data *aux = env->insn_aux_data;
17644 int i, patch_len, delta = 0, len = env->prog->len;
17645 struct bpf_insn *insns = env->prog->insnsi;
17646 struct bpf_prog *new_prog;
17649 rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
17650 zext_patch[1] = BPF_ZEXT_REG(0);
17651 rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
17652 rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
17653 rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
17654 for (i = 0; i < len; i++) {
17655 int adj_idx = i + delta;
17656 struct bpf_insn insn;
17659 insn = insns[adj_idx];
17660 load_reg = insn_def_regno(&insn);
17661 if (!aux[adj_idx].zext_dst) {
17669 class = BPF_CLASS(code);
17670 if (load_reg == -1)
17673 /* NOTE: arg "reg" (the fourth one) is only used for
17674 * BPF_STX + SRC_OP, so it is safe to pass NULL
17677 if (is_reg64(env, &insn, load_reg, NULL, DST_OP)) {
17678 if (class == BPF_LD &&
17679 BPF_MODE(code) == BPF_IMM)
17684 /* ctx load could be transformed into wider load. */
17685 if (class == BPF_LDX &&
17686 aux[adj_idx].ptr_type == PTR_TO_CTX)
17689 imm_rnd = get_random_u32();
17690 rnd_hi32_patch[0] = insn;
17691 rnd_hi32_patch[1].imm = imm_rnd;
17692 rnd_hi32_patch[3].dst_reg = load_reg;
17693 patch = rnd_hi32_patch;
17695 goto apply_patch_buffer;
17698 /* Add in an zero-extend instruction if a) the JIT has requested
17699 * it or b) it's a CMPXCHG.
17701 * The latter is because: BPF_CMPXCHG always loads a value into
17702 * R0, therefore always zero-extends. However some archs'
17703 * equivalent instruction only does this load when the
17704 * comparison is successful. This detail of CMPXCHG is
17705 * orthogonal to the general zero-extension behaviour of the
17706 * CPU, so it's treated independently of bpf_jit_needs_zext.
17708 if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn))
17711 /* Zero-extension is done by the caller. */
17712 if (bpf_pseudo_kfunc_call(&insn))
17715 if (WARN_ON(load_reg == -1)) {
17716 verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n");
17720 zext_patch[0] = insn;
17721 zext_patch[1].dst_reg = load_reg;
17722 zext_patch[1].src_reg = load_reg;
17723 patch = zext_patch;
17725 apply_patch_buffer:
17726 new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
17729 env->prog = new_prog;
17730 insns = new_prog->insnsi;
17731 aux = env->insn_aux_data;
17732 delta += patch_len - 1;
17738 /* convert load instructions that access fields of a context type into a
17739 * sequence of instructions that access fields of the underlying structure:
17740 * struct __sk_buff -> struct sk_buff
17741 * struct bpf_sock_ops -> struct sock
17743 static int convert_ctx_accesses(struct bpf_verifier_env *env)
17745 const struct bpf_verifier_ops *ops = env->ops;
17746 int i, cnt, size, ctx_field_size, delta = 0;
17747 const int insn_cnt = env->prog->len;
17748 struct bpf_insn insn_buf[16], *insn;
17749 u32 target_size, size_default, off;
17750 struct bpf_prog *new_prog;
17751 enum bpf_access_type type;
17752 bool is_narrower_load;
17754 if (ops->gen_prologue || env->seen_direct_write) {
17755 if (!ops->gen_prologue) {
17756 verbose(env, "bpf verifier is misconfigured\n");
17759 cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
17761 if (cnt >= ARRAY_SIZE(insn_buf)) {
17762 verbose(env, "bpf verifier is misconfigured\n");
17765 new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
17769 env->prog = new_prog;
17774 if (bpf_prog_is_offloaded(env->prog->aux))
17777 insn = env->prog->insnsi + delta;
17779 for (i = 0; i < insn_cnt; i++, insn++) {
17780 bpf_convert_ctx_access_t convert_ctx_access;
17783 if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
17784 insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
17785 insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
17786 insn->code == (BPF_LDX | BPF_MEM | BPF_DW) ||
17787 insn->code == (BPF_LDX | BPF_MEMSX | BPF_B) ||
17788 insn->code == (BPF_LDX | BPF_MEMSX | BPF_H) ||
17789 insn->code == (BPF_LDX | BPF_MEMSX | BPF_W)) {
17791 } else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
17792 insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
17793 insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
17794 insn->code == (BPF_STX | BPF_MEM | BPF_DW) ||
17795 insn->code == (BPF_ST | BPF_MEM | BPF_B) ||
17796 insn->code == (BPF_ST | BPF_MEM | BPF_H) ||
17797 insn->code == (BPF_ST | BPF_MEM | BPF_W) ||
17798 insn->code == (BPF_ST | BPF_MEM | BPF_DW)) {
17804 if (type == BPF_WRITE &&
17805 env->insn_aux_data[i + delta].sanitize_stack_spill) {
17806 struct bpf_insn patch[] = {
17811 cnt = ARRAY_SIZE(patch);
17812 new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
17817 env->prog = new_prog;
17818 insn = new_prog->insnsi + i + delta;
17822 switch ((int)env->insn_aux_data[i + delta].ptr_type) {
17824 if (!ops->convert_ctx_access)
17826 convert_ctx_access = ops->convert_ctx_access;
17828 case PTR_TO_SOCKET:
17829 case PTR_TO_SOCK_COMMON:
17830 convert_ctx_access = bpf_sock_convert_ctx_access;
17832 case PTR_TO_TCP_SOCK:
17833 convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
17835 case PTR_TO_XDP_SOCK:
17836 convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
17838 case PTR_TO_BTF_ID:
17839 case PTR_TO_BTF_ID | PTR_UNTRUSTED:
17840 /* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike
17841 * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot
17842 * be said once it is marked PTR_UNTRUSTED, hence we must handle
17843 * any faults for loads into such types. BPF_WRITE is disallowed
17846 case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED:
17847 if (type == BPF_READ) {
17848 if (BPF_MODE(insn->code) == BPF_MEM)
17849 insn->code = BPF_LDX | BPF_PROBE_MEM |
17850 BPF_SIZE((insn)->code);
17852 insn->code = BPF_LDX | BPF_PROBE_MEMSX |
17853 BPF_SIZE((insn)->code);
17854 env->prog->aux->num_exentries++;
17861 ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
17862 size = BPF_LDST_BYTES(insn);
17863 mode = BPF_MODE(insn->code);
17865 /* If the read access is a narrower load of the field,
17866 * convert to a 4/8-byte load, to minimum program type specific
17867 * convert_ctx_access changes. If conversion is successful,
17868 * we will apply proper mask to the result.
17870 is_narrower_load = size < ctx_field_size;
17871 size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
17873 if (is_narrower_load) {
17876 if (type == BPF_WRITE) {
17877 verbose(env, "bpf verifier narrow ctx access misconfigured\n");
17882 if (ctx_field_size == 4)
17884 else if (ctx_field_size == 8)
17885 size_code = BPF_DW;
17887 insn->off = off & ~(size_default - 1);
17888 insn->code = BPF_LDX | BPF_MEM | size_code;
17892 cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
17894 if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
17895 (ctx_field_size && !target_size)) {
17896 verbose(env, "bpf verifier is misconfigured\n");
17900 if (is_narrower_load && size < target_size) {
17901 u8 shift = bpf_ctx_narrow_access_offset(
17902 off, size, size_default) * 8;
17903 if (shift && cnt + 1 >= ARRAY_SIZE(insn_buf)) {
17904 verbose(env, "bpf verifier narrow ctx load misconfigured\n");
17907 if (ctx_field_size <= 4) {
17909 insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
17912 insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
17913 (1 << size * 8) - 1);
17916 insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
17919 insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
17920 (1ULL << size * 8) - 1);
17923 if (mode == BPF_MEMSX)
17924 insn_buf[cnt++] = BPF_RAW_INSN(BPF_ALU64 | BPF_MOV | BPF_X,
17925 insn->dst_reg, insn->dst_reg,
17928 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17934 /* keep walking new program and skip insns we just inserted */
17935 env->prog = new_prog;
17936 insn = new_prog->insnsi + i + delta;
17942 static int jit_subprogs(struct bpf_verifier_env *env)
17944 struct bpf_prog *prog = env->prog, **func, *tmp;
17945 int i, j, subprog_start, subprog_end = 0, len, subprog;
17946 struct bpf_map *map_ptr;
17947 struct bpf_insn *insn;
17948 void *old_bpf_func;
17949 int err, num_exentries;
17951 if (env->subprog_cnt <= 1)
17954 for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
17955 if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
17958 /* Upon error here we cannot fall back to interpreter but
17959 * need a hard reject of the program. Thus -EFAULT is
17960 * propagated in any case.
17962 subprog = find_subprog(env, i + insn->imm + 1);
17964 WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
17965 i + insn->imm + 1);
17968 /* temporarily remember subprog id inside insn instead of
17969 * aux_data, since next loop will split up all insns into funcs
17971 insn->off = subprog;
17972 /* remember original imm in case JIT fails and fallback
17973 * to interpreter will be needed
17975 env->insn_aux_data[i].call_imm = insn->imm;
17976 /* point imm to __bpf_call_base+1 from JITs point of view */
17978 if (bpf_pseudo_func(insn))
17979 /* jit (e.g. x86_64) may emit fewer instructions
17980 * if it learns a u32 imm is the same as a u64 imm.
17981 * Force a non zero here.
17986 err = bpf_prog_alloc_jited_linfo(prog);
17988 goto out_undo_insn;
17991 func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
17993 goto out_undo_insn;
17995 for (i = 0; i < env->subprog_cnt; i++) {
17996 subprog_start = subprog_end;
17997 subprog_end = env->subprog_info[i + 1].start;
17999 len = subprog_end - subprog_start;
18000 /* bpf_prog_run() doesn't call subprogs directly,
18001 * hence main prog stats include the runtime of subprogs.
18002 * subprogs don't have IDs and not reachable via prog_get_next_id
18003 * func[i]->stats will never be accessed and stays NULL
18005 func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
18008 memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
18009 len * sizeof(struct bpf_insn));
18010 func[i]->type = prog->type;
18011 func[i]->len = len;
18012 if (bpf_prog_calc_tag(func[i]))
18014 func[i]->is_func = 1;
18015 func[i]->aux->func_idx = i;
18016 /* Below members will be freed only at prog->aux */
18017 func[i]->aux->btf = prog->aux->btf;
18018 func[i]->aux->func_info = prog->aux->func_info;
18019 func[i]->aux->func_info_cnt = prog->aux->func_info_cnt;
18020 func[i]->aux->poke_tab = prog->aux->poke_tab;
18021 func[i]->aux->size_poke_tab = prog->aux->size_poke_tab;
18023 for (j = 0; j < prog->aux->size_poke_tab; j++) {
18024 struct bpf_jit_poke_descriptor *poke;
18026 poke = &prog->aux->poke_tab[j];
18027 if (poke->insn_idx < subprog_end &&
18028 poke->insn_idx >= subprog_start)
18029 poke->aux = func[i]->aux;
18032 func[i]->aux->name[0] = 'F';
18033 func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
18034 func[i]->jit_requested = 1;
18035 func[i]->blinding_requested = prog->blinding_requested;
18036 func[i]->aux->kfunc_tab = prog->aux->kfunc_tab;
18037 func[i]->aux->kfunc_btf_tab = prog->aux->kfunc_btf_tab;
18038 func[i]->aux->linfo = prog->aux->linfo;
18039 func[i]->aux->nr_linfo = prog->aux->nr_linfo;
18040 func[i]->aux->jited_linfo = prog->aux->jited_linfo;
18041 func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
18043 insn = func[i]->insnsi;
18044 for (j = 0; j < func[i]->len; j++, insn++) {
18045 if (BPF_CLASS(insn->code) == BPF_LDX &&
18046 (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
18047 BPF_MODE(insn->code) == BPF_PROBE_MEMSX))
18050 func[i]->aux->num_exentries = num_exentries;
18051 func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable;
18052 func[i] = bpf_int_jit_compile(func[i]);
18053 if (!func[i]->jited) {
18060 /* at this point all bpf functions were successfully JITed
18061 * now populate all bpf_calls with correct addresses and
18062 * run last pass of JIT
18064 for (i = 0; i < env->subprog_cnt; i++) {
18065 insn = func[i]->insnsi;
18066 for (j = 0; j < func[i]->len; j++, insn++) {
18067 if (bpf_pseudo_func(insn)) {
18068 subprog = insn->off;
18069 insn[0].imm = (u32)(long)func[subprog]->bpf_func;
18070 insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
18073 if (!bpf_pseudo_call(insn))
18075 subprog = insn->off;
18076 insn->imm = BPF_CALL_IMM(func[subprog]->bpf_func);
18079 /* we use the aux data to keep a list of the start addresses
18080 * of the JITed images for each function in the program
18082 * for some architectures, such as powerpc64, the imm field
18083 * might not be large enough to hold the offset of the start
18084 * address of the callee's JITed image from __bpf_call_base
18086 * in such cases, we can lookup the start address of a callee
18087 * by using its subprog id, available from the off field of
18088 * the call instruction, as an index for this list
18090 func[i]->aux->func = func;
18091 func[i]->aux->func_cnt = env->subprog_cnt;
18093 for (i = 0; i < env->subprog_cnt; i++) {
18094 old_bpf_func = func[i]->bpf_func;
18095 tmp = bpf_int_jit_compile(func[i]);
18096 if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
18097 verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
18104 /* finally lock prog and jit images for all functions and
18105 * populate kallsysm. Begin at the first subprogram, since
18106 * bpf_prog_load will add the kallsyms for the main program.
18108 for (i = 1; i < env->subprog_cnt; i++) {
18109 bpf_prog_lock_ro(func[i]);
18110 bpf_prog_kallsyms_add(func[i]);
18113 /* Last step: make now unused interpreter insns from main
18114 * prog consistent for later dump requests, so they can
18115 * later look the same as if they were interpreted only.
18117 for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
18118 if (bpf_pseudo_func(insn)) {
18119 insn[0].imm = env->insn_aux_data[i].call_imm;
18120 insn[1].imm = insn->off;
18124 if (!bpf_pseudo_call(insn))
18126 insn->off = env->insn_aux_data[i].call_imm;
18127 subprog = find_subprog(env, i + insn->off + 1);
18128 insn->imm = subprog;
18132 prog->bpf_func = func[0]->bpf_func;
18133 prog->jited_len = func[0]->jited_len;
18134 prog->aux->extable = func[0]->aux->extable;
18135 prog->aux->num_exentries = func[0]->aux->num_exentries;
18136 prog->aux->func = func;
18137 prog->aux->func_cnt = env->subprog_cnt;
18138 bpf_prog_jit_attempt_done(prog);
18141 /* We failed JIT'ing, so at this point we need to unregister poke
18142 * descriptors from subprogs, so that kernel is not attempting to
18143 * patch it anymore as we're freeing the subprog JIT memory.
18145 for (i = 0; i < prog->aux->size_poke_tab; i++) {
18146 map_ptr = prog->aux->poke_tab[i].tail_call.map;
18147 map_ptr->ops->map_poke_untrack(map_ptr, prog->aux);
18149 /* At this point we're guaranteed that poke descriptors are not
18150 * live anymore. We can just unlink its descriptor table as it's
18151 * released with the main prog.
18153 for (i = 0; i < env->subprog_cnt; i++) {
18156 func[i]->aux->poke_tab = NULL;
18157 bpf_jit_free(func[i]);
18161 /* cleanup main prog to be interpreted */
18162 prog->jit_requested = 0;
18163 prog->blinding_requested = 0;
18164 for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
18165 if (!bpf_pseudo_call(insn))
18168 insn->imm = env->insn_aux_data[i].call_imm;
18170 bpf_prog_jit_attempt_done(prog);
18174 static int fixup_call_args(struct bpf_verifier_env *env)
18176 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
18177 struct bpf_prog *prog = env->prog;
18178 struct bpf_insn *insn = prog->insnsi;
18179 bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
18184 if (env->prog->jit_requested &&
18185 !bpf_prog_is_offloaded(env->prog->aux)) {
18186 err = jit_subprogs(env);
18189 if (err == -EFAULT)
18192 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
18193 if (has_kfunc_call) {
18194 verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
18197 if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
18198 /* When JIT fails the progs with bpf2bpf calls and tail_calls
18199 * have to be rejected, since interpreter doesn't support them yet.
18201 verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
18204 for (i = 0; i < prog->len; i++, insn++) {
18205 if (bpf_pseudo_func(insn)) {
18206 /* When JIT fails the progs with callback calls
18207 * have to be rejected, since interpreter doesn't support them yet.
18209 verbose(env, "callbacks are not allowed in non-JITed programs\n");
18213 if (!bpf_pseudo_call(insn))
18215 depth = get_callee_stack_depth(env, insn, i);
18218 bpf_patch_call_args(insn, depth);
18225 /* replace a generic kfunc with a specialized version if necessary */
18226 static void specialize_kfunc(struct bpf_verifier_env *env,
18227 u32 func_id, u16 offset, unsigned long *addr)
18229 struct bpf_prog *prog = env->prog;
18230 bool seen_direct_write;
18234 if (bpf_dev_bound_kfunc_id(func_id)) {
18235 xdp_kfunc = bpf_dev_bound_resolve_kfunc(prog, func_id);
18237 *addr = (unsigned long)xdp_kfunc;
18240 /* fallback to default kfunc when not supported by netdev */
18246 if (func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
18247 seen_direct_write = env->seen_direct_write;
18248 is_rdonly = !may_access_direct_pkt_data(env, NULL, BPF_WRITE);
18251 *addr = (unsigned long)bpf_dynptr_from_skb_rdonly;
18253 /* restore env->seen_direct_write to its original value, since
18254 * may_access_direct_pkt_data mutates it
18256 env->seen_direct_write = seen_direct_write;
18260 static void __fixup_collection_insert_kfunc(struct bpf_insn_aux_data *insn_aux,
18261 u16 struct_meta_reg,
18262 u16 node_offset_reg,
18263 struct bpf_insn *insn,
18264 struct bpf_insn *insn_buf,
18267 struct btf_struct_meta *kptr_struct_meta = insn_aux->kptr_struct_meta;
18268 struct bpf_insn addr[2] = { BPF_LD_IMM64(struct_meta_reg, (long)kptr_struct_meta) };
18270 insn_buf[0] = addr[0];
18271 insn_buf[1] = addr[1];
18272 insn_buf[2] = BPF_MOV64_IMM(node_offset_reg, insn_aux->insert_off);
18273 insn_buf[3] = *insn;
18277 static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
18278 struct bpf_insn *insn_buf, int insn_idx, int *cnt)
18280 const struct bpf_kfunc_desc *desc;
18283 verbose(env, "invalid kernel function call not eliminated in verifier pass\n");
18289 /* insn->imm has the btf func_id. Replace it with an offset relative to
18290 * __bpf_call_base, unless the JIT needs to call functions that are
18291 * further than 32 bits away (bpf_jit_supports_far_kfunc_call()).
18293 desc = find_kfunc_desc(env->prog, insn->imm, insn->off);
18295 verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n",
18300 if (!bpf_jit_supports_far_kfunc_call())
18301 insn->imm = BPF_CALL_IMM(desc->addr);
18304 if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
18305 struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
18306 struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
18307 u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size;
18309 insn_buf[0] = BPF_MOV64_IMM(BPF_REG_1, obj_new_size);
18310 insn_buf[1] = addr[0];
18311 insn_buf[2] = addr[1];
18312 insn_buf[3] = *insn;
18314 } else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl] ||
18315 desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
18316 struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
18317 struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
18319 if (desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
18320 !kptr_struct_meta) {
18321 verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n",
18326 insn_buf[0] = addr[0];
18327 insn_buf[1] = addr[1];
18328 insn_buf[2] = *insn;
18330 } else if (desc->func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
18331 desc->func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
18332 desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
18333 struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
18334 int struct_meta_reg = BPF_REG_3;
18335 int node_offset_reg = BPF_REG_4;
18337 /* rbtree_add has extra 'less' arg, so args-to-fixup are in diff regs */
18338 if (desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
18339 struct_meta_reg = BPF_REG_4;
18340 node_offset_reg = BPF_REG_5;
18343 if (!kptr_struct_meta) {
18344 verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n",
18349 __fixup_collection_insert_kfunc(&env->insn_aux_data[insn_idx], struct_meta_reg,
18350 node_offset_reg, insn, insn_buf, cnt);
18351 } else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] ||
18352 desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
18353 insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
18359 /* Do various post-verification rewrites in a single program pass.
18360 * These rewrites simplify JIT and interpreter implementations.
18362 static int do_misc_fixups(struct bpf_verifier_env *env)
18364 struct bpf_prog *prog = env->prog;
18365 enum bpf_attach_type eatype = prog->expected_attach_type;
18366 enum bpf_prog_type prog_type = resolve_prog_type(prog);
18367 struct bpf_insn *insn = prog->insnsi;
18368 const struct bpf_func_proto *fn;
18369 const int insn_cnt = prog->len;
18370 const struct bpf_map_ops *ops;
18371 struct bpf_insn_aux_data *aux;
18372 struct bpf_insn insn_buf[16];
18373 struct bpf_prog *new_prog;
18374 struct bpf_map *map_ptr;
18375 int i, ret, cnt, delta = 0;
18377 for (i = 0; i < insn_cnt; i++, insn++) {
18378 /* Make divide-by-zero exceptions impossible. */
18379 if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
18380 insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
18381 insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
18382 insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
18383 bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
18384 bool isdiv = BPF_OP(insn->code) == BPF_DIV;
18385 struct bpf_insn *patchlet;
18386 struct bpf_insn chk_and_div[] = {
18387 /* [R,W]x div 0 -> 0 */
18388 BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
18389 BPF_JNE | BPF_K, insn->src_reg,
18391 BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
18392 BPF_JMP_IMM(BPF_JA, 0, 0, 1),
18395 struct bpf_insn chk_and_mod[] = {
18396 /* [R,W]x mod 0 -> [R,W]x */
18397 BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
18398 BPF_JEQ | BPF_K, insn->src_reg,
18399 0, 1 + (is64 ? 0 : 1), 0),
18401 BPF_JMP_IMM(BPF_JA, 0, 0, 1),
18402 BPF_MOV32_REG(insn->dst_reg, insn->dst_reg),
18405 patchlet = isdiv ? chk_and_div : chk_and_mod;
18406 cnt = isdiv ? ARRAY_SIZE(chk_and_div) :
18407 ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0);
18409 new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
18414 env->prog = prog = new_prog;
18415 insn = new_prog->insnsi + i + delta;
18419 /* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
18420 if (BPF_CLASS(insn->code) == BPF_LD &&
18421 (BPF_MODE(insn->code) == BPF_ABS ||
18422 BPF_MODE(insn->code) == BPF_IND)) {
18423 cnt = env->ops->gen_ld_abs(insn, insn_buf);
18424 if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
18425 verbose(env, "bpf verifier is misconfigured\n");
18429 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18434 env->prog = prog = new_prog;
18435 insn = new_prog->insnsi + i + delta;
18439 /* Rewrite pointer arithmetic to mitigate speculation attacks. */
18440 if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
18441 insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
18442 const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
18443 const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
18444 struct bpf_insn *patch = &insn_buf[0];
18445 bool issrc, isneg, isimm;
18448 aux = &env->insn_aux_data[i + delta];
18449 if (!aux->alu_state ||
18450 aux->alu_state == BPF_ALU_NON_POINTER)
18453 isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
18454 issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
18455 BPF_ALU_SANITIZE_SRC;
18456 isimm = aux->alu_state & BPF_ALU_IMMEDIATE;
18458 off_reg = issrc ? insn->src_reg : insn->dst_reg;
18460 *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
18463 *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
18464 *patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
18465 *patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
18466 *patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
18467 *patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
18468 *patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
18469 *patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
18472 *patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
18473 insn->src_reg = BPF_REG_AX;
18475 insn->code = insn->code == code_add ?
18476 code_sub : code_add;
18478 if (issrc && isneg && !isimm)
18479 *patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
18480 cnt = patch - insn_buf;
18482 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18487 env->prog = prog = new_prog;
18488 insn = new_prog->insnsi + i + delta;
18492 if (insn->code != (BPF_JMP | BPF_CALL))
18494 if (insn->src_reg == BPF_PSEUDO_CALL)
18496 if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
18497 ret = fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt);
18503 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18508 env->prog = prog = new_prog;
18509 insn = new_prog->insnsi + i + delta;
18513 if (insn->imm == BPF_FUNC_get_route_realm)
18514 prog->dst_needed = 1;
18515 if (insn->imm == BPF_FUNC_get_prandom_u32)
18516 bpf_user_rnd_init_once();
18517 if (insn->imm == BPF_FUNC_override_return)
18518 prog->kprobe_override = 1;
18519 if (insn->imm == BPF_FUNC_tail_call) {
18520 /* If we tail call into other programs, we
18521 * cannot make any assumptions since they can
18522 * be replaced dynamically during runtime in
18523 * the program array.
18525 prog->cb_access = 1;
18526 if (!allow_tail_call_in_subprogs(env))
18527 prog->aux->stack_depth = MAX_BPF_STACK;
18528 prog->aux->max_pkt_offset = MAX_PACKET_OFF;
18530 /* mark bpf_tail_call as different opcode to avoid
18531 * conditional branch in the interpreter for every normal
18532 * call and to prevent accidental JITing by JIT compiler
18533 * that doesn't support bpf_tail_call yet
18536 insn->code = BPF_JMP | BPF_TAIL_CALL;
18538 aux = &env->insn_aux_data[i + delta];
18539 if (env->bpf_capable && !prog->blinding_requested &&
18540 prog->jit_requested &&
18541 !bpf_map_key_poisoned(aux) &&
18542 !bpf_map_ptr_poisoned(aux) &&
18543 !bpf_map_ptr_unpriv(aux)) {
18544 struct bpf_jit_poke_descriptor desc = {
18545 .reason = BPF_POKE_REASON_TAIL_CALL,
18546 .tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
18547 .tail_call.key = bpf_map_key_immediate(aux),
18548 .insn_idx = i + delta,
18551 ret = bpf_jit_add_poke_descriptor(prog, &desc);
18553 verbose(env, "adding tail call poke descriptor failed\n");
18557 insn->imm = ret + 1;
18561 if (!bpf_map_ptr_unpriv(aux))
18564 /* instead of changing every JIT dealing with tail_call
18565 * emit two extra insns:
18566 * if (index >= max_entries) goto out;
18567 * index &= array->index_mask;
18568 * to avoid out-of-bounds cpu speculation
18570 if (bpf_map_ptr_poisoned(aux)) {
18571 verbose(env, "tail_call abusing map_ptr\n");
18575 map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
18576 insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
18577 map_ptr->max_entries, 2);
18578 insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
18579 container_of(map_ptr,
18582 insn_buf[2] = *insn;
18584 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18589 env->prog = prog = new_prog;
18590 insn = new_prog->insnsi + i + delta;
18594 if (insn->imm == BPF_FUNC_timer_set_callback) {
18595 /* The verifier will process callback_fn as many times as necessary
18596 * with different maps and the register states prepared by
18597 * set_timer_callback_state will be accurate.
18599 * The following use case is valid:
18600 * map1 is shared by prog1, prog2, prog3.
18601 * prog1 calls bpf_timer_init for some map1 elements
18602 * prog2 calls bpf_timer_set_callback for some map1 elements.
18603 * Those that were not bpf_timer_init-ed will return -EINVAL.
18604 * prog3 calls bpf_timer_start for some map1 elements.
18605 * Those that were not both bpf_timer_init-ed and
18606 * bpf_timer_set_callback-ed will return -EINVAL.
18608 struct bpf_insn ld_addrs[2] = {
18609 BPF_LD_IMM64(BPF_REG_3, (long)prog->aux),
18612 insn_buf[0] = ld_addrs[0];
18613 insn_buf[1] = ld_addrs[1];
18614 insn_buf[2] = *insn;
18617 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18622 env->prog = prog = new_prog;
18623 insn = new_prog->insnsi + i + delta;
18624 goto patch_call_imm;
18627 if (is_storage_get_function(insn->imm)) {
18628 if (!env->prog->aux->sleepable ||
18629 env->insn_aux_data[i + delta].storage_get_func_atomic)
18630 insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
18632 insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
18633 insn_buf[1] = *insn;
18636 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18641 env->prog = prog = new_prog;
18642 insn = new_prog->insnsi + i + delta;
18643 goto patch_call_imm;
18646 /* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
18647 * and other inlining handlers are currently limited to 64 bit
18650 if (prog->jit_requested && BITS_PER_LONG == 64 &&
18651 (insn->imm == BPF_FUNC_map_lookup_elem ||
18652 insn->imm == BPF_FUNC_map_update_elem ||
18653 insn->imm == BPF_FUNC_map_delete_elem ||
18654 insn->imm == BPF_FUNC_map_push_elem ||
18655 insn->imm == BPF_FUNC_map_pop_elem ||
18656 insn->imm == BPF_FUNC_map_peek_elem ||
18657 insn->imm == BPF_FUNC_redirect_map ||
18658 insn->imm == BPF_FUNC_for_each_map_elem ||
18659 insn->imm == BPF_FUNC_map_lookup_percpu_elem)) {
18660 aux = &env->insn_aux_data[i + delta];
18661 if (bpf_map_ptr_poisoned(aux))
18662 goto patch_call_imm;
18664 map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
18665 ops = map_ptr->ops;
18666 if (insn->imm == BPF_FUNC_map_lookup_elem &&
18667 ops->map_gen_lookup) {
18668 cnt = ops->map_gen_lookup(map_ptr, insn_buf);
18669 if (cnt == -EOPNOTSUPP)
18670 goto patch_map_ops_generic;
18671 if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) {
18672 verbose(env, "bpf verifier is misconfigured\n");
18676 new_prog = bpf_patch_insn_data(env, i + delta,
18682 env->prog = prog = new_prog;
18683 insn = new_prog->insnsi + i + delta;
18687 BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
18688 (void *(*)(struct bpf_map *map, void *key))NULL));
18689 BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
18690 (long (*)(struct bpf_map *map, void *key))NULL));
18691 BUILD_BUG_ON(!__same_type(ops->map_update_elem,
18692 (long (*)(struct bpf_map *map, void *key, void *value,
18694 BUILD_BUG_ON(!__same_type(ops->map_push_elem,
18695 (long (*)(struct bpf_map *map, void *value,
18697 BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
18698 (long (*)(struct bpf_map *map, void *value))NULL));
18699 BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
18700 (long (*)(struct bpf_map *map, void *value))NULL));
18701 BUILD_BUG_ON(!__same_type(ops->map_redirect,
18702 (long (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
18703 BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
18704 (long (*)(struct bpf_map *map,
18705 bpf_callback_t callback_fn,
18706 void *callback_ctx,
18708 BUILD_BUG_ON(!__same_type(ops->map_lookup_percpu_elem,
18709 (void *(*)(struct bpf_map *map, void *key, u32 cpu))NULL));
18711 patch_map_ops_generic:
18712 switch (insn->imm) {
18713 case BPF_FUNC_map_lookup_elem:
18714 insn->imm = BPF_CALL_IMM(ops->map_lookup_elem);
18716 case BPF_FUNC_map_update_elem:
18717 insn->imm = BPF_CALL_IMM(ops->map_update_elem);
18719 case BPF_FUNC_map_delete_elem:
18720 insn->imm = BPF_CALL_IMM(ops->map_delete_elem);
18722 case BPF_FUNC_map_push_elem:
18723 insn->imm = BPF_CALL_IMM(ops->map_push_elem);
18725 case BPF_FUNC_map_pop_elem:
18726 insn->imm = BPF_CALL_IMM(ops->map_pop_elem);
18728 case BPF_FUNC_map_peek_elem:
18729 insn->imm = BPF_CALL_IMM(ops->map_peek_elem);
18731 case BPF_FUNC_redirect_map:
18732 insn->imm = BPF_CALL_IMM(ops->map_redirect);
18734 case BPF_FUNC_for_each_map_elem:
18735 insn->imm = BPF_CALL_IMM(ops->map_for_each_callback);
18737 case BPF_FUNC_map_lookup_percpu_elem:
18738 insn->imm = BPF_CALL_IMM(ops->map_lookup_percpu_elem);
18742 goto patch_call_imm;
18745 /* Implement bpf_jiffies64 inline. */
18746 if (prog->jit_requested && BITS_PER_LONG == 64 &&
18747 insn->imm == BPF_FUNC_jiffies64) {
18748 struct bpf_insn ld_jiffies_addr[2] = {
18749 BPF_LD_IMM64(BPF_REG_0,
18750 (unsigned long)&jiffies),
18753 insn_buf[0] = ld_jiffies_addr[0];
18754 insn_buf[1] = ld_jiffies_addr[1];
18755 insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
18759 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
18765 env->prog = prog = new_prog;
18766 insn = new_prog->insnsi + i + delta;
18770 /* Implement bpf_get_func_arg inline. */
18771 if (prog_type == BPF_PROG_TYPE_TRACING &&
18772 insn->imm == BPF_FUNC_get_func_arg) {
18773 /* Load nr_args from ctx - 8 */
18774 insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
18775 insn_buf[1] = BPF_JMP32_REG(BPF_JGE, BPF_REG_2, BPF_REG_0, 6);
18776 insn_buf[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 3);
18777 insn_buf[3] = BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1);
18778 insn_buf[4] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0);
18779 insn_buf[5] = BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
18780 insn_buf[6] = BPF_MOV64_IMM(BPF_REG_0, 0);
18781 insn_buf[7] = BPF_JMP_A(1);
18782 insn_buf[8] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);
18785 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18790 env->prog = prog = new_prog;
18791 insn = new_prog->insnsi + i + delta;
18795 /* Implement bpf_get_func_ret inline. */
18796 if (prog_type == BPF_PROG_TYPE_TRACING &&
18797 insn->imm == BPF_FUNC_get_func_ret) {
18798 if (eatype == BPF_TRACE_FEXIT ||
18799 eatype == BPF_MODIFY_RETURN) {
18800 /* Load nr_args from ctx - 8 */
18801 insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
18802 insn_buf[1] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
18803 insn_buf[2] = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
18804 insn_buf[3] = BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
18805 insn_buf[4] = BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_3, 0);
18806 insn_buf[5] = BPF_MOV64_IMM(BPF_REG_0, 0);
18809 insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, -EOPNOTSUPP);
18813 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
18818 env->prog = prog = new_prog;
18819 insn = new_prog->insnsi + i + delta;
18823 /* Implement get_func_arg_cnt inline. */
18824 if (prog_type == BPF_PROG_TYPE_TRACING &&
18825 insn->imm == BPF_FUNC_get_func_arg_cnt) {
18826 /* Load nr_args from ctx - 8 */
18827 insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
18829 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
18833 env->prog = prog = new_prog;
18834 insn = new_prog->insnsi + i + delta;
18838 /* Implement bpf_get_func_ip inline. */
18839 if (prog_type == BPF_PROG_TYPE_TRACING &&
18840 insn->imm == BPF_FUNC_get_func_ip) {
18841 /* Load IP address from ctx - 16 */
18842 insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -16);
18844 new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
18848 env->prog = prog = new_prog;
18849 insn = new_prog->insnsi + i + delta;
18854 fn = env->ops->get_func_proto(insn->imm, env->prog);
18855 /* all functions that have prototype and verifier allowed
18856 * programs to call them, must be real in-kernel functions
18860 "kernel subsystem misconfigured func %s#%d\n",
18861 func_id_name(insn->imm), insn->imm);
18864 insn->imm = fn->func - __bpf_call_base;
18867 /* Since poke tab is now finalized, publish aux to tracker. */
18868 for (i = 0; i < prog->aux->size_poke_tab; i++) {
18869 map_ptr = prog->aux->poke_tab[i].tail_call.map;
18870 if (!map_ptr->ops->map_poke_track ||
18871 !map_ptr->ops->map_poke_untrack ||
18872 !map_ptr->ops->map_poke_run) {
18873 verbose(env, "bpf verifier is misconfigured\n");
18877 ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
18879 verbose(env, "tracking tail call prog failed\n");
18884 sort_kfunc_descs_by_imm_off(env->prog);
18889 static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
18892 u32 callback_subprogno,
18895 s32 r6_offset = stack_base + 0 * BPF_REG_SIZE;
18896 s32 r7_offset = stack_base + 1 * BPF_REG_SIZE;
18897 s32 r8_offset = stack_base + 2 * BPF_REG_SIZE;
18898 int reg_loop_max = BPF_REG_6;
18899 int reg_loop_cnt = BPF_REG_7;
18900 int reg_loop_ctx = BPF_REG_8;
18902 struct bpf_prog *new_prog;
18903 u32 callback_start;
18904 u32 call_insn_offset;
18905 s32 callback_offset;
18907 /* This represents an inlined version of bpf_iter.c:bpf_loop,
18908 * be careful to modify this code in sync.
18910 struct bpf_insn insn_buf[] = {
18911 /* Return error and jump to the end of the patch if
18912 * expected number of iterations is too big.
18914 BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2),
18915 BPF_MOV32_IMM(BPF_REG_0, -E2BIG),
18916 BPF_JMP_IMM(BPF_JA, 0, 0, 16),
18917 /* spill R6, R7, R8 to use these as loop vars */
18918 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset),
18919 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset),
18920 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset),
18921 /* initialize loop vars */
18922 BPF_MOV64_REG(reg_loop_max, BPF_REG_1),
18923 BPF_MOV32_IMM(reg_loop_cnt, 0),
18924 BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3),
18926 * if reg_loop_cnt >= reg_loop_max skip the loop body
18928 BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5),
18930 * correct callback offset would be set after patching
18932 BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt),
18933 BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx),
18935 /* increment loop counter */
18936 BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1),
18937 /* jump to loop header if callback returned 0 */
18938 BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6),
18939 /* return value of bpf_loop,
18940 * set R0 to the number of iterations
18942 BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt),
18943 /* restore original values of R6, R7, R8 */
18944 BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset),
18945 BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset),
18946 BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset),
18949 *cnt = ARRAY_SIZE(insn_buf);
18950 new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt);
18954 /* callback start is known only after patching */
18955 callback_start = env->subprog_info[callback_subprogno].start;
18956 /* Note: insn_buf[12] is an offset of BPF_CALL_REL instruction */
18957 call_insn_offset = position + 12;
18958 callback_offset = callback_start - call_insn_offset - 1;
18959 new_prog->insnsi[call_insn_offset].imm = callback_offset;
18964 static bool is_bpf_loop_call(struct bpf_insn *insn)
18966 return insn->code == (BPF_JMP | BPF_CALL) &&
18967 insn->src_reg == 0 &&
18968 insn->imm == BPF_FUNC_loop;
18971 /* For all sub-programs in the program (including main) check
18972 * insn_aux_data to see if there are bpf_loop calls that require
18973 * inlining. If such calls are found the calls are replaced with a
18974 * sequence of instructions produced by `inline_bpf_loop` function and
18975 * subprog stack_depth is increased by the size of 3 registers.
18976 * This stack space is used to spill values of the R6, R7, R8. These
18977 * registers are used to store the loop bound, counter and context
18980 static int optimize_bpf_loop(struct bpf_verifier_env *env)
18982 struct bpf_subprog_info *subprogs = env->subprog_info;
18983 int i, cur_subprog = 0, cnt, delta = 0;
18984 struct bpf_insn *insn = env->prog->insnsi;
18985 int insn_cnt = env->prog->len;
18986 u16 stack_depth = subprogs[cur_subprog].stack_depth;
18987 u16 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
18988 u16 stack_depth_extra = 0;
18990 for (i = 0; i < insn_cnt; i++, insn++) {
18991 struct bpf_loop_inline_state *inline_state =
18992 &env->insn_aux_data[i + delta].loop_inline_state;
18994 if (is_bpf_loop_call(insn) && inline_state->fit_for_inline) {
18995 struct bpf_prog *new_prog;
18997 stack_depth_extra = BPF_REG_SIZE * 3 + stack_depth_roundup;
18998 new_prog = inline_bpf_loop(env,
19000 -(stack_depth + stack_depth_extra),
19001 inline_state->callback_subprogno,
19007 env->prog = new_prog;
19008 insn = new_prog->insnsi + i + delta;
19011 if (subprogs[cur_subprog + 1].start == i + delta + 1) {
19012 subprogs[cur_subprog].stack_depth += stack_depth_extra;
19014 stack_depth = subprogs[cur_subprog].stack_depth;
19015 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
19016 stack_depth_extra = 0;
19020 env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
19025 static void free_states(struct bpf_verifier_env *env)
19027 struct bpf_verifier_state_list *sl, *sln;
19030 sl = env->free_list;
19033 free_verifier_state(&sl->state, false);
19037 env->free_list = NULL;
19039 if (!env->explored_states)
19042 for (i = 0; i < state_htab_size(env); i++) {
19043 sl = env->explored_states[i];
19047 free_verifier_state(&sl->state, false);
19051 env->explored_states[i] = NULL;
19055 static int do_check_common(struct bpf_verifier_env *env, int subprog)
19057 bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
19058 struct bpf_verifier_state *state;
19059 struct bpf_reg_state *regs;
19062 env->prev_linfo = NULL;
19065 state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
19068 state->curframe = 0;
19069 state->speculative = false;
19070 state->branches = 1;
19071 state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
19072 if (!state->frame[0]) {
19076 env->cur_state = state;
19077 init_func_state(env, state->frame[0],
19078 BPF_MAIN_FUNC /* callsite */,
19081 state->first_insn_idx = env->subprog_info[subprog].start;
19082 state->last_insn_idx = -1;
19084 regs = state->frame[state->curframe]->regs;
19085 if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) {
19086 ret = btf_prepare_func_args(env, subprog, regs);
19089 for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
19090 if (regs[i].type == PTR_TO_CTX)
19091 mark_reg_known_zero(env, regs, i);
19092 else if (regs[i].type == SCALAR_VALUE)
19093 mark_reg_unknown(env, regs, i);
19094 else if (base_type(regs[i].type) == PTR_TO_MEM) {
19095 const u32 mem_size = regs[i].mem_size;
19097 mark_reg_known_zero(env, regs, i);
19098 regs[i].mem_size = mem_size;
19099 regs[i].id = ++env->id_gen;
19103 /* 1st arg to a function */
19104 regs[BPF_REG_1].type = PTR_TO_CTX;
19105 mark_reg_known_zero(env, regs, BPF_REG_1);
19106 ret = btf_check_subprog_arg_match(env, subprog, regs);
19107 if (ret == -EFAULT)
19108 /* unlikely verifier bug. abort.
19109 * ret == 0 and ret < 0 are sadly acceptable for
19110 * main() function due to backward compatibility.
19111 * Like socket filter program may be written as:
19112 * int bpf_prog(struct pt_regs *ctx)
19113 * and never dereference that ctx in the program.
19114 * 'struct pt_regs' is a type mismatch for socket
19115 * filter that should be using 'struct __sk_buff'.
19120 ret = do_check(env);
19122 /* check for NULL is necessary, since cur_state can be freed inside
19123 * do_check() under memory pressure.
19125 if (env->cur_state) {
19126 free_verifier_state(env->cur_state, true);
19127 env->cur_state = NULL;
19129 while (!pop_stack(env, NULL, NULL, false));
19130 if (!ret && pop_log)
19131 bpf_vlog_reset(&env->log, 0);
19136 /* Verify all global functions in a BPF program one by one based on their BTF.
19137 * All global functions must pass verification. Otherwise the whole program is rejected.
19148 * foo() will be verified first for R1=any_scalar_value. During verification it
19149 * will be assumed that bar() already verified successfully and call to bar()
19150 * from foo() will be checked for type match only. Later bar() will be verified
19151 * independently to check that it's safe for R1=any_scalar_value.
19153 static int do_check_subprogs(struct bpf_verifier_env *env)
19155 struct bpf_prog_aux *aux = env->prog->aux;
19158 if (!aux->func_info)
19161 for (i = 1; i < env->subprog_cnt; i++) {
19162 if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL)
19164 env->insn_idx = env->subprog_info[i].start;
19165 WARN_ON_ONCE(env->insn_idx == 0);
19166 ret = do_check_common(env, i);
19169 } else if (env->log.level & BPF_LOG_LEVEL) {
19171 "Func#%d is safe for any args that match its prototype\n",
19178 static int do_check_main(struct bpf_verifier_env *env)
19183 ret = do_check_common(env, 0);
19185 env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
19190 static void print_verification_stats(struct bpf_verifier_env *env)
19194 if (env->log.level & BPF_LOG_STATS) {
19195 verbose(env, "verification time %lld usec\n",
19196 div_u64(env->verification_time, 1000));
19197 verbose(env, "stack depth ");
19198 for (i = 0; i < env->subprog_cnt; i++) {
19199 u32 depth = env->subprog_info[i].stack_depth;
19201 verbose(env, "%d", depth);
19202 if (i + 1 < env->subprog_cnt)
19205 verbose(env, "\n");
19207 verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
19208 "total_states %d peak_states %d mark_read %d\n",
19209 env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
19210 env->max_states_per_insn, env->total_states,
19211 env->peak_states, env->longest_mark_read_walk);
19214 static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
19216 const struct btf_type *t, *func_proto;
19217 const struct bpf_struct_ops *st_ops;
19218 const struct btf_member *member;
19219 struct bpf_prog *prog = env->prog;
19220 u32 btf_id, member_idx;
19223 if (!prog->gpl_compatible) {
19224 verbose(env, "struct ops programs must have a GPL compatible license\n");
19228 btf_id = prog->aux->attach_btf_id;
19229 st_ops = bpf_struct_ops_find(btf_id);
19231 verbose(env, "attach_btf_id %u is not a supported struct\n",
19237 member_idx = prog->expected_attach_type;
19238 if (member_idx >= btf_type_vlen(t)) {
19239 verbose(env, "attach to invalid member idx %u of struct %s\n",
19240 member_idx, st_ops->name);
19244 member = &btf_type_member(t)[member_idx];
19245 mname = btf_name_by_offset(btf_vmlinux, member->name_off);
19246 func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
19249 verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
19250 mname, member_idx, st_ops->name);
19254 if (st_ops->check_member) {
19255 int err = st_ops->check_member(t, member, prog);
19258 verbose(env, "attach to unsupported member %s of struct %s\n",
19259 mname, st_ops->name);
19264 prog->aux->attach_func_proto = func_proto;
19265 prog->aux->attach_func_name = mname;
19266 env->ops = st_ops->verifier_ops;
19270 #define SECURITY_PREFIX "security_"
19272 static int check_attach_modify_return(unsigned long addr, const char *func_name)
19274 if (within_error_injection_list(addr) ||
19275 !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1))
19281 /* list of non-sleepable functions that are otherwise on
19282 * ALLOW_ERROR_INJECTION list
19284 BTF_SET_START(btf_non_sleepable_error_inject)
19285 /* Three functions below can be called from sleepable and non-sleepable context.
19286 * Assume non-sleepable from bpf safety point of view.
19288 BTF_ID(func, __filemap_add_folio)
19289 BTF_ID(func, should_fail_alloc_page)
19290 BTF_ID(func, should_failslab)
19291 BTF_SET_END(btf_non_sleepable_error_inject)
19293 static int check_non_sleepable_error_inject(u32 btf_id)
19295 return btf_id_set_contains(&btf_non_sleepable_error_inject, btf_id);
19298 int bpf_check_attach_target(struct bpf_verifier_log *log,
19299 const struct bpf_prog *prog,
19300 const struct bpf_prog *tgt_prog,
19302 struct bpf_attach_target_info *tgt_info)
19304 bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
19305 const char prefix[] = "btf_trace_";
19306 int ret = 0, subprog = -1, i;
19307 const struct btf_type *t;
19308 bool conservative = true;
19312 struct module *mod = NULL;
19315 bpf_log(log, "Tracing programs must provide btf_id\n");
19318 btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
19321 "FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
19324 t = btf_type_by_id(btf, btf_id);
19326 bpf_log(log, "attach_btf_id %u is invalid\n", btf_id);
19329 tname = btf_name_by_offset(btf, t->name_off);
19331 bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id);
19335 struct bpf_prog_aux *aux = tgt_prog->aux;
19337 if (bpf_prog_is_dev_bound(prog->aux) &&
19338 !bpf_prog_dev_bound_match(prog, tgt_prog)) {
19339 bpf_log(log, "Target program bound device mismatch");
19343 for (i = 0; i < aux->func_info_cnt; i++)
19344 if (aux->func_info[i].type_id == btf_id) {
19348 if (subprog == -1) {
19349 bpf_log(log, "Subprog %s doesn't exist\n", tname);
19352 conservative = aux->func_info_aux[subprog].unreliable;
19353 if (prog_extension) {
19354 if (conservative) {
19356 "Cannot replace static functions\n");
19359 if (!prog->jit_requested) {
19361 "Extension programs should be JITed\n");
19365 if (!tgt_prog->jited) {
19366 bpf_log(log, "Can attach to only JITed progs\n");
19369 if (tgt_prog->type == prog->type) {
19370 /* Cannot fentry/fexit another fentry/fexit program.
19371 * Cannot attach program extension to another extension.
19372 * It's ok to attach fentry/fexit to extension program.
19374 bpf_log(log, "Cannot recursively attach\n");
19377 if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
19379 (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
19380 tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) {
19381 /* Program extensions can extend all program types
19382 * except fentry/fexit. The reason is the following.
19383 * The fentry/fexit programs are used for performance
19384 * analysis, stats and can be attached to any program
19385 * type except themselves. When extension program is
19386 * replacing XDP function it is necessary to allow
19387 * performance analysis of all functions. Both original
19388 * XDP program and its program extension. Hence
19389 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
19390 * allowed. If extending of fentry/fexit was allowed it
19391 * would be possible to create long call chain
19392 * fentry->extension->fentry->extension beyond
19393 * reasonable stack size. Hence extending fentry is not
19396 bpf_log(log, "Cannot extend fentry/fexit\n");
19400 if (prog_extension) {
19401 bpf_log(log, "Cannot replace kernel functions\n");
19406 switch (prog->expected_attach_type) {
19407 case BPF_TRACE_RAW_TP:
19410 "Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
19413 if (!btf_type_is_typedef(t)) {
19414 bpf_log(log, "attach_btf_id %u is not a typedef\n",
19418 if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
19419 bpf_log(log, "attach_btf_id %u points to wrong type name %s\n",
19423 tname += sizeof(prefix) - 1;
19424 t = btf_type_by_id(btf, t->type);
19425 if (!btf_type_is_ptr(t))
19426 /* should never happen in valid vmlinux build */
19428 t = btf_type_by_id(btf, t->type);
19429 if (!btf_type_is_func_proto(t))
19430 /* should never happen in valid vmlinux build */
19434 case BPF_TRACE_ITER:
19435 if (!btf_type_is_func(t)) {
19436 bpf_log(log, "attach_btf_id %u is not a function\n",
19440 t = btf_type_by_id(btf, t->type);
19441 if (!btf_type_is_func_proto(t))
19443 ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
19448 if (!prog_extension)
19451 case BPF_MODIFY_RETURN:
19453 case BPF_LSM_CGROUP:
19454 case BPF_TRACE_FENTRY:
19455 case BPF_TRACE_FEXIT:
19456 if (!btf_type_is_func(t)) {
19457 bpf_log(log, "attach_btf_id %u is not a function\n",
19461 if (prog_extension &&
19462 btf_check_type_match(log, prog, btf, t))
19464 t = btf_type_by_id(btf, t->type);
19465 if (!btf_type_is_func_proto(t))
19468 if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) &&
19469 (!tgt_prog || prog->aux->saved_dst_prog_type != tgt_prog->type ||
19470 prog->aux->saved_dst_attach_type != tgt_prog->expected_attach_type))
19473 if (tgt_prog && conservative)
19476 ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
19482 addr = (long) tgt_prog->bpf_func;
19484 addr = (long) tgt_prog->aux->func[subprog]->bpf_func;
19486 if (btf_is_module(btf)) {
19487 mod = btf_try_get_module(btf);
19489 addr = find_kallsyms_symbol_value(mod, tname);
19493 addr = kallsyms_lookup_name(tname);
19498 "The address of function %s cannot be found\n",
19504 if (prog->aux->sleepable) {
19506 switch (prog->type) {
19507 case BPF_PROG_TYPE_TRACING:
19509 /* fentry/fexit/fmod_ret progs can be sleepable if they are
19510 * attached to ALLOW_ERROR_INJECTION and are not in denylist.
19512 if (!check_non_sleepable_error_inject(btf_id) &&
19513 within_error_injection_list(addr))
19515 /* fentry/fexit/fmod_ret progs can also be sleepable if they are
19516 * in the fmodret id set with the KF_SLEEPABLE flag.
19519 u32 *flags = btf_kfunc_is_modify_return(btf, btf_id,
19522 if (flags && (*flags & KF_SLEEPABLE))
19526 case BPF_PROG_TYPE_LSM:
19527 /* LSM progs check that they are attached to bpf_lsm_*() funcs.
19528 * Only some of them are sleepable.
19530 if (bpf_lsm_is_sleepable_hook(btf_id))
19538 bpf_log(log, "%s is not sleepable\n", tname);
19541 } else if (prog->expected_attach_type == BPF_MODIFY_RETURN) {
19544 bpf_log(log, "can't modify return codes of BPF programs\n");
19548 if (btf_kfunc_is_modify_return(btf, btf_id, prog) ||
19549 !check_attach_modify_return(addr, tname))
19553 bpf_log(log, "%s() is not modifiable\n", tname);
19560 tgt_info->tgt_addr = addr;
19561 tgt_info->tgt_name = tname;
19562 tgt_info->tgt_type = t;
19563 tgt_info->tgt_mod = mod;
19567 BTF_SET_START(btf_id_deny)
19570 BTF_ID(func, migrate_disable)
19571 BTF_ID(func, migrate_enable)
19573 #if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
19574 BTF_ID(func, rcu_read_unlock_strict)
19576 #if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
19577 BTF_ID(func, preempt_count_add)
19578 BTF_ID(func, preempt_count_sub)
19580 #ifdef CONFIG_PREEMPT_RCU
19581 BTF_ID(func, __rcu_read_lock)
19582 BTF_ID(func, __rcu_read_unlock)
19584 BTF_SET_END(btf_id_deny)
19586 static bool can_be_sleepable(struct bpf_prog *prog)
19588 if (prog->type == BPF_PROG_TYPE_TRACING) {
19589 switch (prog->expected_attach_type) {
19590 case BPF_TRACE_FENTRY:
19591 case BPF_TRACE_FEXIT:
19592 case BPF_MODIFY_RETURN:
19593 case BPF_TRACE_ITER:
19599 return prog->type == BPF_PROG_TYPE_LSM ||
19600 prog->type == BPF_PROG_TYPE_KPROBE /* only for uprobes */ ||
19601 prog->type == BPF_PROG_TYPE_STRUCT_OPS;
19604 static int check_attach_btf_id(struct bpf_verifier_env *env)
19606 struct bpf_prog *prog = env->prog;
19607 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
19608 struct bpf_attach_target_info tgt_info = {};
19609 u32 btf_id = prog->aux->attach_btf_id;
19610 struct bpf_trampoline *tr;
19614 if (prog->type == BPF_PROG_TYPE_SYSCALL) {
19615 if (prog->aux->sleepable)
19616 /* attach_btf_id checked to be zero already */
19618 verbose(env, "Syscall programs can only be sleepable\n");
19622 if (prog->aux->sleepable && !can_be_sleepable(prog)) {
19623 verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable\n");
19627 if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
19628 return check_struct_ops_btf_id(env);
19630 if (prog->type != BPF_PROG_TYPE_TRACING &&
19631 prog->type != BPF_PROG_TYPE_LSM &&
19632 prog->type != BPF_PROG_TYPE_EXT)
19635 ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info);
19639 if (tgt_prog && prog->type == BPF_PROG_TYPE_EXT) {
19640 /* to make freplace equivalent to their targets, they need to
19641 * inherit env->ops and expected_attach_type for the rest of the
19644 env->ops = bpf_verifier_ops[tgt_prog->type];
19645 prog->expected_attach_type = tgt_prog->expected_attach_type;
19648 /* store info about the attachment target that will be used later */
19649 prog->aux->attach_func_proto = tgt_info.tgt_type;
19650 prog->aux->attach_func_name = tgt_info.tgt_name;
19651 prog->aux->mod = tgt_info.tgt_mod;
19654 prog->aux->saved_dst_prog_type = tgt_prog->type;
19655 prog->aux->saved_dst_attach_type = tgt_prog->expected_attach_type;
19658 if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
19659 prog->aux->attach_btf_trace = true;
19661 } else if (prog->expected_attach_type == BPF_TRACE_ITER) {
19662 if (!bpf_iter_prog_supported(prog))
19667 if (prog->type == BPF_PROG_TYPE_LSM) {
19668 ret = bpf_lsm_verify_prog(&env->log, prog);
19671 } else if (prog->type == BPF_PROG_TYPE_TRACING &&
19672 btf_id_set_contains(&btf_id_deny, btf_id)) {
19676 key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
19677 tr = bpf_trampoline_get(key, &tgt_info);
19681 if (tgt_prog && tgt_prog->aux->tail_call_reachable)
19682 tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX;
19684 prog->aux->dst_trampoline = tr;
19688 struct btf *bpf_get_btf_vmlinux(void)
19690 if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
19691 mutex_lock(&bpf_verifier_lock);
19693 btf_vmlinux = btf_parse_vmlinux();
19694 mutex_unlock(&bpf_verifier_lock);
19696 return btf_vmlinux;
19699 int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
19701 u64 start_time = ktime_get_ns();
19702 struct bpf_verifier_env *env;
19703 int i, len, ret = -EINVAL, err;
19707 /* no program is valid */
19708 if (ARRAY_SIZE(bpf_verifier_ops) == 0)
19711 /* 'struct bpf_verifier_env' can be global, but since it's not small,
19712 * allocate/free it every time bpf_check() is called
19714 env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
19720 len = (*prog)->len;
19721 env->insn_aux_data =
19722 vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
19724 if (!env->insn_aux_data)
19726 for (i = 0; i < len; i++)
19727 env->insn_aux_data[i].orig_idx = i;
19729 env->ops = bpf_verifier_ops[env->prog->type];
19730 env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
19731 is_priv = bpf_capable();
19733 bpf_get_btf_vmlinux();
19735 /* grab the mutex to protect few globals used by verifier */
19737 mutex_lock(&bpf_verifier_lock);
19739 /* user could have requested verbose verifier output
19740 * and supplied buffer to store the verification trace
19742 ret = bpf_vlog_init(&env->log, attr->log_level,
19743 (char __user *) (unsigned long) attr->log_buf,
19748 mark_verifier_state_clean(env);
19750 if (IS_ERR(btf_vmlinux)) {
19751 /* Either gcc or pahole or kernel are broken. */
19752 verbose(env, "in-kernel BTF is malformed\n");
19753 ret = PTR_ERR(btf_vmlinux);
19754 goto skip_full_check;
19757 env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
19758 if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
19759 env->strict_alignment = true;
19760 if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
19761 env->strict_alignment = false;
19763 env->allow_ptr_leaks = bpf_allow_ptr_leaks();
19764 env->allow_uninit_stack = bpf_allow_uninit_stack();
19765 env->bypass_spec_v1 = bpf_bypass_spec_v1();
19766 env->bypass_spec_v4 = bpf_bypass_spec_v4();
19767 env->bpf_capable = bpf_capable();
19770 env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
19772 env->explored_states = kvcalloc(state_htab_size(env),
19773 sizeof(struct bpf_verifier_state_list *),
19776 if (!env->explored_states)
19777 goto skip_full_check;
19779 ret = add_subprog_and_kfunc(env);
19781 goto skip_full_check;
19783 ret = check_subprogs(env);
19785 goto skip_full_check;
19787 ret = check_btf_info(env, attr, uattr);
19789 goto skip_full_check;
19791 ret = check_attach_btf_id(env);
19793 goto skip_full_check;
19795 ret = resolve_pseudo_ldimm64(env);
19797 goto skip_full_check;
19799 if (bpf_prog_is_offloaded(env->prog->aux)) {
19800 ret = bpf_prog_offload_verifier_prep(env->prog);
19802 goto skip_full_check;
19805 ret = check_cfg(env);
19807 goto skip_full_check;
19809 ret = do_check_subprogs(env);
19810 ret = ret ?: do_check_main(env);
19812 if (ret == 0 && bpf_prog_is_offloaded(env->prog->aux))
19813 ret = bpf_prog_offload_finalize(env);
19816 kvfree(env->explored_states);
19819 ret = check_max_stack_depth(env);
19821 /* instruction rewrites happen after this point */
19823 ret = optimize_bpf_loop(env);
19827 opt_hard_wire_dead_code_branches(env);
19829 ret = opt_remove_dead_code(env);
19831 ret = opt_remove_nops(env);
19834 sanitize_dead_code(env);
19838 /* program is valid, convert *(u32*)(ctx + off) accesses */
19839 ret = convert_ctx_accesses(env);
19842 ret = do_misc_fixups(env);
19844 /* do 32-bit optimization after insn patching has done so those patched
19845 * insns could be handled correctly.
19847 if (ret == 0 && !bpf_prog_is_offloaded(env->prog->aux)) {
19848 ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
19849 env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
19854 ret = fixup_call_args(env);
19856 env->verification_time = ktime_get_ns() - start_time;
19857 print_verification_stats(env);
19858 env->prog->aux->verified_insns = env->insn_processed;
19860 /* preserve original error even if log finalization is successful */
19861 err = bpf_vlog_finalize(&env->log, &log_true_size);
19865 if (uattr_size >= offsetofend(union bpf_attr, log_true_size) &&
19866 copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size),
19867 &log_true_size, sizeof(log_true_size))) {
19869 goto err_release_maps;
19873 goto err_release_maps;
19875 if (env->used_map_cnt) {
19876 /* if program passed verifier, update used_maps in bpf_prog_info */
19877 env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
19878 sizeof(env->used_maps[0]),
19881 if (!env->prog->aux->used_maps) {
19883 goto err_release_maps;
19886 memcpy(env->prog->aux->used_maps, env->used_maps,
19887 sizeof(env->used_maps[0]) * env->used_map_cnt);
19888 env->prog->aux->used_map_cnt = env->used_map_cnt;
19890 if (env->used_btf_cnt) {
19891 /* if program passed verifier, update used_btfs in bpf_prog_aux */
19892 env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt,
19893 sizeof(env->used_btfs[0]),
19895 if (!env->prog->aux->used_btfs) {
19897 goto err_release_maps;
19900 memcpy(env->prog->aux->used_btfs, env->used_btfs,
19901 sizeof(env->used_btfs[0]) * env->used_btf_cnt);
19902 env->prog->aux->used_btf_cnt = env->used_btf_cnt;
19904 if (env->used_map_cnt || env->used_btf_cnt) {
19905 /* program is valid. Convert pseudo bpf_ld_imm64 into generic
19906 * bpf_ld_imm64 instructions
19908 convert_pseudo_ld_imm64(env);
19911 adjust_btf_func(env);
19914 if (!env->prog->aux->used_maps)
19915 /* if we didn't copy map pointers into bpf_prog_info, release
19916 * them now. Otherwise free_used_maps() will release them.
19919 if (!env->prog->aux->used_btfs)
19922 /* extension progs temporarily inherit the attach_type of their targets
19923 for verification purposes, so set it back to zero before returning
19925 if (env->prog->type == BPF_PROG_TYPE_EXT)
19926 env->prog->expected_attach_type = 0;
19931 mutex_unlock(&bpf_verifier_lock);
19932 vfree(env->insn_aux_data);