1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (c) 2018 Facebook */
4 #include <uapi/linux/btf.h>
5 #include <uapi/linux/types.h>
6 #include <linux/seq_file.h>
7 #include <linux/compiler.h>
8 #include <linux/errno.h>
9 #include <linux/slab.h>
10 #include <linux/anon_inodes.h>
11 #include <linux/file.h>
12 #include <linux/uaccess.h>
13 #include <linux/kernel.h>
14 #include <linux/idr.h>
15 #include <linux/sort.h>
16 #include <linux/bpf_verifier.h>
17 #include <linux/btf.h>
19 /* BTF (BPF Type Format) is the meta data format which describes
20 * the data types of BPF program/map. Hence, it basically focus
21 * on the C programming language which the modern BPF is primary
26 * The BTF data is stored under the ".BTF" ELF section
30 * Each 'struct btf_type' object describes a C data type.
31 * Depending on the type it is describing, a 'struct btf_type'
32 * object may be followed by more data. F.e.
33 * To describe an array, 'struct btf_type' is followed by
36 * 'struct btf_type' and any extra data following it are
41 * The BTF type section contains a list of 'struct btf_type' objects.
42 * Each one describes a C type. Recall from the above section
43 * that a 'struct btf_type' object could be immediately followed by extra
44 * data in order to desribe some particular C types.
48 * Each btf_type object is identified by a type_id. The type_id
49 * is implicitly implied by the location of the btf_type object in
50 * the BTF type section. The first one has type_id 1. The second
51 * one has type_id 2...etc. Hence, an earlier btf_type has
54 * A btf_type object may refer to another btf_type object by using
55 * type_id (i.e. the "type" in the "struct btf_type").
57 * NOTE that we cannot assume any reference-order.
58 * A btf_type object can refer to an earlier btf_type object
59 * but it can also refer to a later btf_type object.
61 * For example, to describe "const void *". A btf_type
62 * object describing "const" may refer to another btf_type
63 * object describing "void *". This type-reference is done
64 * by specifying type_id:
66 * [1] CONST (anon) type_id=2
67 * [2] PTR (anon) type_id=0
69 * The above is the btf_verifier debug log:
70 * - Each line started with "[?]" is a btf_type object
71 * - [?] is the type_id of the btf_type object.
72 * - CONST/PTR is the BTF_KIND_XXX
73 * - "(anon)" is the name of the type. It just
74 * happens that CONST and PTR has no name.
75 * - type_id=XXX is the 'u32 type' in btf_type
77 * NOTE: "void" has type_id 0
81 * The BTF string section contains the names used by the type section.
82 * Each string is referred by an "offset" from the beginning of the
85 * Each string is '\0' terminated.
87 * The first character in the string section must be '\0'
88 * which is used to mean 'anonymous'. Some btf_type may not
94 * To verify BTF data, two passes are needed.
98 * The first pass is to collect all btf_type objects to
99 * an array: "btf->types".
101 * Depending on the C type that a btf_type is describing,
102 * a btf_type may be followed by extra data. We don't know
103 * how many btf_type is there, and more importantly we don't
104 * know where each btf_type is located in the type section.
106 * Without knowing the location of each type_id, most verifications
107 * cannot be done. e.g. an earlier btf_type may refer to a later
108 * btf_type (recall the "const void *" above), so we cannot
109 * check this type-reference in the first pass.
111 * In the first pass, it still does some verifications (e.g.
112 * checking the name is a valid offset to the string section).
116 * The main focus is to resolve a btf_type that is referring
119 * We have to ensure the referring type:
120 * 1) does exist in the BTF (i.e. in btf->types[])
121 * 2) does not cause a loop:
130 * btf_type_needs_resolve() decides if a btf_type needs
133 * The needs_resolve type implements the "resolve()" ops which
134 * essentially does a DFS and detects backedge.
136 * During resolve (or DFS), different C types have different
137 * "RESOLVED" conditions.
139 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
140 * members because a member is always referring to another
141 * type. A struct's member can be treated as "RESOLVED" if
142 * it is referring to a BTF_KIND_PTR. Otherwise, the
143 * following valid C struct would be rejected:
150 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
151 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
152 * detect a pointer loop, e.g.:
153 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
155 * +-----------------------------------------+
159 #define BITS_PER_U64 (sizeof(u64) * BITS_PER_BYTE)
160 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
161 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
162 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
163 #define BITS_ROUNDUP_BYTES(bits) \
164 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
166 #define BTF_INFO_MASK 0x0f00ffff
167 #define BTF_INT_MASK 0x0fffffff
168 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
169 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
171 /* 16MB for 64k structs and each has 16 members and
172 * a few MB spaces for the string section.
173 * The hard limit is S32_MAX.
175 #define BTF_MAX_SIZE (16 * 1024 * 1024)
177 #define for_each_member(i, struct_type, member) \
178 for (i = 0, member = btf_type_member(struct_type); \
179 i < btf_type_vlen(struct_type); \
182 #define for_each_member_from(i, from, struct_type, member) \
183 for (i = from, member = btf_type_member(struct_type) + from; \
184 i < btf_type_vlen(struct_type); \
187 static DEFINE_IDR(btf_idr);
188 static DEFINE_SPINLOCK(btf_idr_lock);
192 struct btf_type **types;
197 struct btf_header hdr;
206 enum verifier_phase {
211 struct resolve_vertex {
212 const struct btf_type *t;
224 RESOLVE_TBD, /* To Be Determined */
225 RESOLVE_PTR, /* Resolving for Pointer */
226 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
231 #define MAX_RESOLVE_DEPTH 32
233 struct btf_sec_info {
238 struct btf_verifier_env {
241 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
242 struct bpf_verifier_log log;
245 enum verifier_phase phase;
246 enum resolve_mode resolve_mode;
249 static const char * const btf_kind_str[NR_BTF_KINDS] = {
250 [BTF_KIND_UNKN] = "UNKNOWN",
251 [BTF_KIND_INT] = "INT",
252 [BTF_KIND_PTR] = "PTR",
253 [BTF_KIND_ARRAY] = "ARRAY",
254 [BTF_KIND_STRUCT] = "STRUCT",
255 [BTF_KIND_UNION] = "UNION",
256 [BTF_KIND_ENUM] = "ENUM",
257 [BTF_KIND_FWD] = "FWD",
258 [BTF_KIND_TYPEDEF] = "TYPEDEF",
259 [BTF_KIND_VOLATILE] = "VOLATILE",
260 [BTF_KIND_CONST] = "CONST",
261 [BTF_KIND_RESTRICT] = "RESTRICT",
264 struct btf_kind_operations {
265 s32 (*check_meta)(struct btf_verifier_env *env,
266 const struct btf_type *t,
268 int (*resolve)(struct btf_verifier_env *env,
269 const struct resolve_vertex *v);
270 int (*check_member)(struct btf_verifier_env *env,
271 const struct btf_type *struct_type,
272 const struct btf_member *member,
273 const struct btf_type *member_type);
274 void (*log_details)(struct btf_verifier_env *env,
275 const struct btf_type *t);
276 void (*seq_show)(const struct btf *btf, const struct btf_type *t,
277 u32 type_id, void *data, u8 bits_offsets,
281 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
282 static struct btf_type btf_void;
284 static bool btf_type_is_modifier(const struct btf_type *t)
286 /* Some of them is not strictly a C modifier
287 * but they are grouped into the same bucket
289 * A type (t) that refers to another
290 * type through t->type AND its size cannot
291 * be determined without following the t->type.
293 * ptr does not fall into this bucket
294 * because its size is always sizeof(void *).
296 switch (BTF_INFO_KIND(t->info)) {
297 case BTF_KIND_TYPEDEF:
298 case BTF_KIND_VOLATILE:
300 case BTF_KIND_RESTRICT:
307 static bool btf_type_is_void(const struct btf_type *t)
309 /* void => no type and size info.
310 * Hence, FWD is also treated as void.
312 return t == &btf_void || BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
315 static bool btf_type_is_void_or_null(const struct btf_type *t)
317 return !t || btf_type_is_void(t);
320 /* union is only a special case of struct:
321 * all its offsetof(member) == 0
323 static bool btf_type_is_struct(const struct btf_type *t)
325 u8 kind = BTF_INFO_KIND(t->info);
327 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
330 static bool btf_type_is_array(const struct btf_type *t)
332 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
335 static bool btf_type_is_ptr(const struct btf_type *t)
337 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
340 static bool btf_type_is_int(const struct btf_type *t)
342 return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
345 /* What types need to be resolved?
347 * btf_type_is_modifier() is an obvious one.
349 * btf_type_is_struct() because its member refers to
350 * another type (through member->type).
352 * btf_type_is_array() because its element (array->type)
353 * refers to another type. Array can be thought of a
354 * special case of struct while array just has the same
355 * member-type repeated by array->nelems of times.
357 static bool btf_type_needs_resolve(const struct btf_type *t)
359 return btf_type_is_modifier(t) ||
360 btf_type_is_ptr(t) ||
361 btf_type_is_struct(t) ||
362 btf_type_is_array(t);
365 /* t->size can be used */
366 static bool btf_type_has_size(const struct btf_type *t)
368 switch (BTF_INFO_KIND(t->info)) {
370 case BTF_KIND_STRUCT:
379 static const char *btf_int_encoding_str(u8 encoding)
383 else if (encoding == BTF_INT_SIGNED)
385 else if (encoding == BTF_INT_CHAR)
387 else if (encoding == BTF_INT_BOOL)
393 static u16 btf_type_vlen(const struct btf_type *t)
395 return BTF_INFO_VLEN(t->info);
398 static u32 btf_type_int(const struct btf_type *t)
400 return *(u32 *)(t + 1);
403 static const struct btf_array *btf_type_array(const struct btf_type *t)
405 return (const struct btf_array *)(t + 1);
408 static const struct btf_member *btf_type_member(const struct btf_type *t)
410 return (const struct btf_member *)(t + 1);
413 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
415 return (const struct btf_enum *)(t + 1);
418 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
420 return kind_ops[BTF_INFO_KIND(t->info)];
423 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
425 return BTF_STR_OFFSET_VALID(offset) &&
426 offset < btf->hdr.str_len;
429 static const char *btf_name_by_offset(const struct btf *btf, u32 offset)
433 else if (offset < btf->hdr.str_len)
434 return &btf->strings[offset];
436 return "(invalid-name-offset)";
439 static const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
441 if (type_id > btf->nr_types)
444 return btf->types[type_id];
448 * Regular int is not a bit field and it must be either
451 static bool btf_type_int_is_regular(const struct btf_type *t)
453 u8 nr_bits, nr_bytes;
456 int_data = btf_type_int(t);
457 nr_bits = BTF_INT_BITS(int_data);
458 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
459 if (BITS_PER_BYTE_MASKED(nr_bits) ||
460 BTF_INT_OFFSET(int_data) ||
461 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
462 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64))) {
469 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
470 const char *fmt, ...)
475 bpf_verifier_vlog(log, fmt, args);
479 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
480 const char *fmt, ...)
482 struct bpf_verifier_log *log = &env->log;
485 if (!bpf_verifier_log_needed(log))
489 bpf_verifier_vlog(log, fmt, args);
493 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
494 const struct btf_type *t,
496 const char *fmt, ...)
498 struct bpf_verifier_log *log = &env->log;
499 u8 kind = BTF_INFO_KIND(t->info);
500 struct btf *btf = env->btf;
503 if (!bpf_verifier_log_needed(log))
506 __btf_verifier_log(log, "[%u] %s %s%s",
509 btf_name_by_offset(btf, t->name_off),
510 log_details ? " " : "");
513 btf_type_ops(t)->log_details(env, t);
516 __btf_verifier_log(log, " ");
518 bpf_verifier_vlog(log, fmt, args);
522 __btf_verifier_log(log, "\n");
525 #define btf_verifier_log_type(env, t, ...) \
526 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
527 #define btf_verifier_log_basic(env, t, ...) \
528 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
531 static void btf_verifier_log_member(struct btf_verifier_env *env,
532 const struct btf_type *struct_type,
533 const struct btf_member *member,
534 const char *fmt, ...)
536 struct bpf_verifier_log *log = &env->log;
537 struct btf *btf = env->btf;
540 if (!bpf_verifier_log_needed(log))
543 /* The CHECK_META phase already did a btf dump.
545 * If member is logged again, it must hit an error in
546 * parsing this member. It is useful to print out which
547 * struct this member belongs to.
549 if (env->phase != CHECK_META)
550 btf_verifier_log_type(env, struct_type, NULL);
552 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
553 btf_name_by_offset(btf, member->name_off),
554 member->type, member->offset);
557 __btf_verifier_log(log, " ");
559 bpf_verifier_vlog(log, fmt, args);
563 __btf_verifier_log(log, "\n");
566 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
569 struct bpf_verifier_log *log = &env->log;
570 const struct btf *btf = env->btf;
571 const struct btf_header *hdr;
573 if (!bpf_verifier_log_needed(log))
577 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
578 __btf_verifier_log(log, "version: %u\n", hdr->version);
579 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
580 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
581 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
582 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
583 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
584 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
585 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
588 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
590 struct btf *btf = env->btf;
592 /* < 2 because +1 for btf_void which is always in btf->types[0].
593 * btf_void is not accounted in btf->nr_types because btf_void
594 * does not come from the BTF file.
596 if (btf->types_size - btf->nr_types < 2) {
597 /* Expand 'types' array */
599 struct btf_type **new_types;
600 u32 expand_by, new_size;
602 if (btf->types_size == BTF_MAX_TYPE) {
603 btf_verifier_log(env, "Exceeded max num of types");
607 expand_by = max_t(u32, btf->types_size >> 2, 16);
608 new_size = min_t(u32, BTF_MAX_TYPE,
609 btf->types_size + expand_by);
611 new_types = kvcalloc(new_size, sizeof(*new_types),
612 GFP_KERNEL | __GFP_NOWARN);
616 if (btf->nr_types == 0)
617 new_types[0] = &btf_void;
619 memcpy(new_types, btf->types,
620 sizeof(*btf->types) * (btf->nr_types + 1));
623 btf->types = new_types;
624 btf->types_size = new_size;
627 btf->types[++(btf->nr_types)] = t;
632 static int btf_alloc_id(struct btf *btf)
636 idr_preload(GFP_KERNEL);
637 spin_lock_bh(&btf_idr_lock);
638 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
641 spin_unlock_bh(&btf_idr_lock);
644 if (WARN_ON_ONCE(!id))
647 return id > 0 ? 0 : id;
650 static void btf_free_id(struct btf *btf)
655 * In map-in-map, calling map_delete_elem() on outer
656 * map will call bpf_map_put on the inner map.
657 * It will then eventually call btf_free_id()
658 * on the inner map. Some of the map_delete_elem()
659 * implementation may have irq disabled, so
660 * we need to use the _irqsave() version instead
661 * of the _bh() version.
663 spin_lock_irqsave(&btf_idr_lock, flags);
664 idr_remove(&btf_idr, btf->id);
665 spin_unlock_irqrestore(&btf_idr_lock, flags);
668 static void btf_free(struct btf *btf)
671 kvfree(btf->resolved_sizes);
672 kvfree(btf->resolved_ids);
677 static void btf_free_rcu(struct rcu_head *rcu)
679 struct btf *btf = container_of(rcu, struct btf, rcu);
684 void btf_put(struct btf *btf)
686 if (btf && refcount_dec_and_test(&btf->refcnt)) {
688 call_rcu(&btf->rcu, btf_free_rcu);
692 static int env_resolve_init(struct btf_verifier_env *env)
694 struct btf *btf = env->btf;
695 u32 nr_types = btf->nr_types;
696 u32 *resolved_sizes = NULL;
697 u32 *resolved_ids = NULL;
698 u8 *visit_states = NULL;
700 /* +1 for btf_void */
701 resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
702 GFP_KERNEL | __GFP_NOWARN);
706 resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
707 GFP_KERNEL | __GFP_NOWARN);
711 visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
712 GFP_KERNEL | __GFP_NOWARN);
716 btf->resolved_sizes = resolved_sizes;
717 btf->resolved_ids = resolved_ids;
718 env->visit_states = visit_states;
723 kvfree(resolved_sizes);
724 kvfree(resolved_ids);
725 kvfree(visit_states);
729 static void btf_verifier_env_free(struct btf_verifier_env *env)
731 kvfree(env->visit_states);
735 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
736 const struct btf_type *next_type)
738 switch (env->resolve_mode) {
740 /* int, enum or void is a sink */
741 return !btf_type_needs_resolve(next_type);
743 /* int, enum, void, struct or array is a sink for ptr */
744 return !btf_type_is_modifier(next_type) &&
745 !btf_type_is_ptr(next_type);
746 case RESOLVE_STRUCT_OR_ARRAY:
747 /* int, enum, void or ptr is a sink for struct and array */
748 return !btf_type_is_modifier(next_type) &&
749 !btf_type_is_array(next_type) &&
750 !btf_type_is_struct(next_type);
756 static bool env_type_is_resolved(const struct btf_verifier_env *env,
759 return env->visit_states[type_id] == RESOLVED;
762 static int env_stack_push(struct btf_verifier_env *env,
763 const struct btf_type *t, u32 type_id)
765 struct resolve_vertex *v;
767 if (env->top_stack == MAX_RESOLVE_DEPTH)
770 if (env->visit_states[type_id] != NOT_VISITED)
773 env->visit_states[type_id] = VISITED;
775 v = &env->stack[env->top_stack++];
777 v->type_id = type_id;
780 if (env->resolve_mode == RESOLVE_TBD) {
781 if (btf_type_is_ptr(t))
782 env->resolve_mode = RESOLVE_PTR;
783 else if (btf_type_is_struct(t) || btf_type_is_array(t))
784 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
790 static void env_stack_set_next_member(struct btf_verifier_env *env,
793 env->stack[env->top_stack - 1].next_member = next_member;
796 static void env_stack_pop_resolved(struct btf_verifier_env *env,
797 u32 resolved_type_id,
800 u32 type_id = env->stack[--(env->top_stack)].type_id;
801 struct btf *btf = env->btf;
803 btf->resolved_sizes[type_id] = resolved_size;
804 btf->resolved_ids[type_id] = resolved_type_id;
805 env->visit_states[type_id] = RESOLVED;
808 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
810 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
813 /* The input param "type_id" must point to a needs_resolve type */
814 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
817 *type_id = btf->resolved_ids[*type_id];
818 return btf_type_by_id(btf, *type_id);
821 const struct btf_type *btf_type_id_size(const struct btf *btf,
822 u32 *type_id, u32 *ret_size)
824 const struct btf_type *size_type;
825 u32 size_type_id = *type_id;
828 size_type = btf_type_by_id(btf, size_type_id);
829 if (btf_type_is_void_or_null(size_type))
832 if (btf_type_has_size(size_type)) {
833 size = size_type->size;
834 } else if (btf_type_is_array(size_type)) {
835 size = btf->resolved_sizes[size_type_id];
836 } else if (btf_type_is_ptr(size_type)) {
837 size = sizeof(void *);
839 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type)))
842 size = btf->resolved_sizes[size_type_id];
843 size_type_id = btf->resolved_ids[size_type_id];
844 size_type = btf_type_by_id(btf, size_type_id);
845 if (btf_type_is_void(size_type))
849 *type_id = size_type_id;
856 static int btf_df_check_member(struct btf_verifier_env *env,
857 const struct btf_type *struct_type,
858 const struct btf_member *member,
859 const struct btf_type *member_type)
861 btf_verifier_log_basic(env, struct_type,
862 "Unsupported check_member");
866 static int btf_df_resolve(struct btf_verifier_env *env,
867 const struct resolve_vertex *v)
869 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
873 static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t,
874 u32 type_id, void *data, u8 bits_offsets,
877 seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
880 static int btf_int_check_member(struct btf_verifier_env *env,
881 const struct btf_type *struct_type,
882 const struct btf_member *member,
883 const struct btf_type *member_type)
885 u32 int_data = btf_type_int(member_type);
886 u32 struct_bits_off = member->offset;
887 u32 struct_size = struct_type->size;
891 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
892 btf_verifier_log_member(env, struct_type, member,
893 "bits_offset exceeds U32_MAX");
897 struct_bits_off += BTF_INT_OFFSET(int_data);
898 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
899 nr_copy_bits = BTF_INT_BITS(int_data) +
900 BITS_PER_BYTE_MASKED(struct_bits_off);
902 if (nr_copy_bits > BITS_PER_U64) {
903 btf_verifier_log_member(env, struct_type, member,
904 "nr_copy_bits exceeds 64");
908 if (struct_size < bytes_offset ||
909 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
910 btf_verifier_log_member(env, struct_type, member,
911 "Member exceeds struct_size");
918 static s32 btf_int_check_meta(struct btf_verifier_env *env,
919 const struct btf_type *t,
922 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
925 if (meta_left < meta_needed) {
926 btf_verifier_log_basic(env, t,
927 "meta_left:%u meta_needed:%u",
928 meta_left, meta_needed);
932 if (btf_type_vlen(t)) {
933 btf_verifier_log_type(env, t, "vlen != 0");
937 int_data = btf_type_int(t);
938 if (int_data & ~BTF_INT_MASK) {
939 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
944 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
946 if (nr_bits > BITS_PER_U64) {
947 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
952 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
953 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
958 * Only one of the encoding bits is allowed and it
959 * should be sufficient for the pretty print purpose (i.e. decoding).
960 * Multiple bits can be allowed later if it is found
961 * to be insufficient.
963 encoding = BTF_INT_ENCODING(int_data);
965 encoding != BTF_INT_SIGNED &&
966 encoding != BTF_INT_CHAR &&
967 encoding != BTF_INT_BOOL) {
968 btf_verifier_log_type(env, t, "Unsupported encoding");
972 btf_verifier_log_type(env, t, NULL);
977 static void btf_int_log(struct btf_verifier_env *env,
978 const struct btf_type *t)
980 int int_data = btf_type_int(t);
982 btf_verifier_log(env,
983 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
984 t->size, BTF_INT_OFFSET(int_data),
985 BTF_INT_BITS(int_data),
986 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
989 static void btf_int_bits_seq_show(const struct btf *btf,
990 const struct btf_type *t,
991 void *data, u8 bits_offset,
994 u16 left_shift_bits, right_shift_bits;
995 u32 int_data = btf_type_int(t);
996 u8 nr_bits = BTF_INT_BITS(int_data);
997 u8 total_bits_offset;
1003 * bits_offset is at most 7.
1004 * BTF_INT_OFFSET() cannot exceed 64 bits.
1006 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
1007 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
1008 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
1009 nr_copy_bits = nr_bits + bits_offset;
1010 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
1013 memcpy(&print_num, data, nr_copy_bytes);
1015 #ifdef __BIG_ENDIAN_BITFIELD
1016 left_shift_bits = bits_offset;
1018 left_shift_bits = BITS_PER_U64 - nr_copy_bits;
1020 right_shift_bits = BITS_PER_U64 - nr_bits;
1022 print_num <<= left_shift_bits;
1023 print_num >>= right_shift_bits;
1025 seq_printf(m, "0x%llx", print_num);
1028 static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
1029 u32 type_id, void *data, u8 bits_offset,
1032 u32 int_data = btf_type_int(t);
1033 u8 encoding = BTF_INT_ENCODING(int_data);
1034 bool sign = encoding & BTF_INT_SIGNED;
1035 u8 nr_bits = BTF_INT_BITS(int_data);
1037 if (bits_offset || BTF_INT_OFFSET(int_data) ||
1038 BITS_PER_BYTE_MASKED(nr_bits)) {
1039 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1046 seq_printf(m, "%lld", *(s64 *)data);
1048 seq_printf(m, "%llu", *(u64 *)data);
1052 seq_printf(m, "%d", *(s32 *)data);
1054 seq_printf(m, "%u", *(u32 *)data);
1058 seq_printf(m, "%d", *(s16 *)data);
1060 seq_printf(m, "%u", *(u16 *)data);
1064 seq_printf(m, "%d", *(s8 *)data);
1066 seq_printf(m, "%u", *(u8 *)data);
1069 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1073 static const struct btf_kind_operations int_ops = {
1074 .check_meta = btf_int_check_meta,
1075 .resolve = btf_df_resolve,
1076 .check_member = btf_int_check_member,
1077 .log_details = btf_int_log,
1078 .seq_show = btf_int_seq_show,
1081 static int btf_modifier_check_member(struct btf_verifier_env *env,
1082 const struct btf_type *struct_type,
1083 const struct btf_member *member,
1084 const struct btf_type *member_type)
1086 const struct btf_type *resolved_type;
1087 u32 resolved_type_id = member->type;
1088 struct btf_member resolved_member;
1089 struct btf *btf = env->btf;
1091 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1092 if (!resolved_type) {
1093 btf_verifier_log_member(env, struct_type, member,
1098 resolved_member = *member;
1099 resolved_member.type = resolved_type_id;
1101 return btf_type_ops(resolved_type)->check_member(env, struct_type,
1106 static int btf_ptr_check_member(struct btf_verifier_env *env,
1107 const struct btf_type *struct_type,
1108 const struct btf_member *member,
1109 const struct btf_type *member_type)
1111 u32 struct_size, struct_bits_off, bytes_offset;
1113 struct_size = struct_type->size;
1114 struct_bits_off = member->offset;
1115 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1117 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1118 btf_verifier_log_member(env, struct_type, member,
1119 "Member is not byte aligned");
1123 if (struct_size - bytes_offset < sizeof(void *)) {
1124 btf_verifier_log_member(env, struct_type, member,
1125 "Member exceeds struct_size");
1132 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
1133 const struct btf_type *t,
1136 if (btf_type_vlen(t)) {
1137 btf_verifier_log_type(env, t, "vlen != 0");
1141 if (!BTF_TYPE_ID_VALID(t->type)) {
1142 btf_verifier_log_type(env, t, "Invalid type_id");
1146 btf_verifier_log_type(env, t, NULL);
1151 static int btf_modifier_resolve(struct btf_verifier_env *env,
1152 const struct resolve_vertex *v)
1154 const struct btf_type *t = v->t;
1155 const struct btf_type *next_type;
1156 u32 next_type_id = t->type;
1157 struct btf *btf = env->btf;
1158 u32 next_type_size = 0;
1160 next_type = btf_type_by_id(btf, next_type_id);
1162 btf_verifier_log_type(env, v->t, "Invalid type_id");
1166 /* "typedef void new_void", "const void"...etc */
1167 if (btf_type_is_void(next_type))
1170 if (!env_type_is_resolve_sink(env, next_type) &&
1171 !env_type_is_resolved(env, next_type_id))
1172 return env_stack_push(env, next_type, next_type_id);
1174 /* Figure out the resolved next_type_id with size.
1175 * They will be stored in the current modifier's
1176 * resolved_ids and resolved_sizes such that it can
1177 * save us a few type-following when we use it later (e.g. in
1180 if (!btf_type_id_size(btf, &next_type_id, &next_type_size) &&
1181 !btf_type_is_void(btf_type_id_resolve(btf, &next_type_id))) {
1182 btf_verifier_log_type(env, v->t, "Invalid type_id");
1187 env_stack_pop_resolved(env, next_type_id, next_type_size);
1192 static int btf_ptr_resolve(struct btf_verifier_env *env,
1193 const struct resolve_vertex *v)
1195 const struct btf_type *next_type;
1196 const struct btf_type *t = v->t;
1197 u32 next_type_id = t->type;
1198 struct btf *btf = env->btf;
1199 u32 next_type_size = 0;
1201 next_type = btf_type_by_id(btf, next_type_id);
1203 btf_verifier_log_type(env, v->t, "Invalid type_id");
1208 if (btf_type_is_void(next_type))
1211 if (!env_type_is_resolve_sink(env, next_type) &&
1212 !env_type_is_resolved(env, next_type_id))
1213 return env_stack_push(env, next_type, next_type_id);
1215 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
1216 * the modifier may have stopped resolving when it was resolved
1217 * to a ptr (last-resolved-ptr).
1219 * We now need to continue from the last-resolved-ptr to
1220 * ensure the last-resolved-ptr will not referring back to
1221 * the currenct ptr (t).
1223 if (btf_type_is_modifier(next_type)) {
1224 const struct btf_type *resolved_type;
1225 u32 resolved_type_id;
1227 resolved_type_id = next_type_id;
1228 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
1230 if (btf_type_is_ptr(resolved_type) &&
1231 !env_type_is_resolve_sink(env, resolved_type) &&
1232 !env_type_is_resolved(env, resolved_type_id))
1233 return env_stack_push(env, resolved_type,
1237 if (!btf_type_id_size(btf, &next_type_id, &next_type_size) &&
1238 !btf_type_is_void(btf_type_id_resolve(btf, &next_type_id))) {
1239 btf_verifier_log_type(env, v->t, "Invalid type_id");
1244 env_stack_pop_resolved(env, next_type_id, 0);
1249 static void btf_modifier_seq_show(const struct btf *btf,
1250 const struct btf_type *t,
1251 u32 type_id, void *data,
1252 u8 bits_offset, struct seq_file *m)
1254 t = btf_type_id_resolve(btf, &type_id);
1256 btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
1259 static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t,
1260 u32 type_id, void *data, u8 bits_offset,
1263 /* It is a hashed value */
1264 seq_printf(m, "%p", *(void **)data);
1267 static void btf_ref_type_log(struct btf_verifier_env *env,
1268 const struct btf_type *t)
1270 btf_verifier_log(env, "type_id=%u", t->type);
1273 static struct btf_kind_operations modifier_ops = {
1274 .check_meta = btf_ref_type_check_meta,
1275 .resolve = btf_modifier_resolve,
1276 .check_member = btf_modifier_check_member,
1277 .log_details = btf_ref_type_log,
1278 .seq_show = btf_modifier_seq_show,
1281 static struct btf_kind_operations ptr_ops = {
1282 .check_meta = btf_ref_type_check_meta,
1283 .resolve = btf_ptr_resolve,
1284 .check_member = btf_ptr_check_member,
1285 .log_details = btf_ref_type_log,
1286 .seq_show = btf_ptr_seq_show,
1289 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
1290 const struct btf_type *t,
1293 if (btf_type_vlen(t)) {
1294 btf_verifier_log_type(env, t, "vlen != 0");
1299 btf_verifier_log_type(env, t, "type != 0");
1303 btf_verifier_log_type(env, t, NULL);
1308 static struct btf_kind_operations fwd_ops = {
1309 .check_meta = btf_fwd_check_meta,
1310 .resolve = btf_df_resolve,
1311 .check_member = btf_df_check_member,
1312 .log_details = btf_ref_type_log,
1313 .seq_show = btf_df_seq_show,
1316 static int btf_array_check_member(struct btf_verifier_env *env,
1317 const struct btf_type *struct_type,
1318 const struct btf_member *member,
1319 const struct btf_type *member_type)
1321 u32 struct_bits_off = member->offset;
1322 u32 struct_size, bytes_offset;
1323 u32 array_type_id, array_size;
1324 struct btf *btf = env->btf;
1326 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1327 btf_verifier_log_member(env, struct_type, member,
1328 "Member is not byte aligned");
1332 array_type_id = member->type;
1333 btf_type_id_size(btf, &array_type_id, &array_size);
1334 struct_size = struct_type->size;
1335 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1336 if (struct_size - bytes_offset < array_size) {
1337 btf_verifier_log_member(env, struct_type, member,
1338 "Member exceeds struct_size");
1345 static s32 btf_array_check_meta(struct btf_verifier_env *env,
1346 const struct btf_type *t,
1349 const struct btf_array *array = btf_type_array(t);
1350 u32 meta_needed = sizeof(*array);
1352 if (meta_left < meta_needed) {
1353 btf_verifier_log_basic(env, t,
1354 "meta_left:%u meta_needed:%u",
1355 meta_left, meta_needed);
1359 if (btf_type_vlen(t)) {
1360 btf_verifier_log_type(env, t, "vlen != 0");
1365 btf_verifier_log_type(env, t, "size != 0");
1369 /* Array elem type and index type cannot be in type void,
1370 * so !array->type and !array->index_type are not allowed.
1372 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
1373 btf_verifier_log_type(env, t, "Invalid elem");
1377 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
1378 btf_verifier_log_type(env, t, "Invalid index");
1382 btf_verifier_log_type(env, t, NULL);
1387 static int btf_array_resolve(struct btf_verifier_env *env,
1388 const struct resolve_vertex *v)
1390 const struct btf_array *array = btf_type_array(v->t);
1391 const struct btf_type *elem_type, *index_type;
1392 u32 elem_type_id, index_type_id;
1393 struct btf *btf = env->btf;
1396 /* Check array->index_type */
1397 index_type_id = array->index_type;
1398 index_type = btf_type_by_id(btf, index_type_id);
1399 if (btf_type_is_void_or_null(index_type)) {
1400 btf_verifier_log_type(env, v->t, "Invalid index");
1404 if (!env_type_is_resolve_sink(env, index_type) &&
1405 !env_type_is_resolved(env, index_type_id))
1406 return env_stack_push(env, index_type, index_type_id);
1408 index_type = btf_type_id_size(btf, &index_type_id, NULL);
1409 if (!index_type || !btf_type_is_int(index_type) ||
1410 !btf_type_int_is_regular(index_type)) {
1411 btf_verifier_log_type(env, v->t, "Invalid index");
1415 /* Check array->type */
1416 elem_type_id = array->type;
1417 elem_type = btf_type_by_id(btf, elem_type_id);
1418 if (btf_type_is_void_or_null(elem_type)) {
1419 btf_verifier_log_type(env, v->t,
1424 if (!env_type_is_resolve_sink(env, elem_type) &&
1425 !env_type_is_resolved(env, elem_type_id))
1426 return env_stack_push(env, elem_type, elem_type_id);
1428 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1430 btf_verifier_log_type(env, v->t, "Invalid elem");
1434 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
1435 btf_verifier_log_type(env, v->t, "Invalid array of int");
1439 if (array->nelems && elem_size > U32_MAX / array->nelems) {
1440 btf_verifier_log_type(env, v->t,
1441 "Array size overflows U32_MAX");
1445 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
1450 static void btf_array_log(struct btf_verifier_env *env,
1451 const struct btf_type *t)
1453 const struct btf_array *array = btf_type_array(t);
1455 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
1456 array->type, array->index_type, array->nelems);
1459 static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t,
1460 u32 type_id, void *data, u8 bits_offset,
1463 const struct btf_array *array = btf_type_array(t);
1464 const struct btf_kind_operations *elem_ops;
1465 const struct btf_type *elem_type;
1466 u32 i, elem_size, elem_type_id;
1468 elem_type_id = array->type;
1469 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1470 elem_ops = btf_type_ops(elem_type);
1472 for (i = 0; i < array->nelems; i++) {
1476 elem_ops->seq_show(btf, elem_type, elem_type_id, data,
1483 static struct btf_kind_operations array_ops = {
1484 .check_meta = btf_array_check_meta,
1485 .resolve = btf_array_resolve,
1486 .check_member = btf_array_check_member,
1487 .log_details = btf_array_log,
1488 .seq_show = btf_array_seq_show,
1491 static int btf_struct_check_member(struct btf_verifier_env *env,
1492 const struct btf_type *struct_type,
1493 const struct btf_member *member,
1494 const struct btf_type *member_type)
1496 u32 struct_bits_off = member->offset;
1497 u32 struct_size, bytes_offset;
1499 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1500 btf_verifier_log_member(env, struct_type, member,
1501 "Member is not byte aligned");
1505 struct_size = struct_type->size;
1506 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1507 if (struct_size - bytes_offset < member_type->size) {
1508 btf_verifier_log_member(env, struct_type, member,
1509 "Member exceeds struct_size");
1516 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
1517 const struct btf_type *t,
1520 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
1521 const struct btf_member *member;
1522 u32 meta_needed, last_offset;
1523 struct btf *btf = env->btf;
1524 u32 struct_size = t->size;
1527 meta_needed = btf_type_vlen(t) * sizeof(*member);
1528 if (meta_left < meta_needed) {
1529 btf_verifier_log_basic(env, t,
1530 "meta_left:%u meta_needed:%u",
1531 meta_left, meta_needed);
1535 btf_verifier_log_type(env, t, NULL);
1538 for_each_member(i, t, member) {
1539 if (!btf_name_offset_valid(btf, member->name_off)) {
1540 btf_verifier_log_member(env, t, member,
1541 "Invalid member name_offset:%u",
1546 /* A member cannot be in type void */
1547 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
1548 btf_verifier_log_member(env, t, member,
1553 if (is_union && member->offset) {
1554 btf_verifier_log_member(env, t, member,
1555 "Invalid member bits_offset");
1560 * ">" instead of ">=" because the last member could be
1563 if (last_offset > member->offset) {
1564 btf_verifier_log_member(env, t, member,
1565 "Invalid member bits_offset");
1569 if (BITS_ROUNDUP_BYTES(member->offset) > struct_size) {
1570 btf_verifier_log_member(env, t, member,
1571 "Memmber bits_offset exceeds its struct size");
1575 btf_verifier_log_member(env, t, member, NULL);
1576 last_offset = member->offset;
1582 static int btf_struct_resolve(struct btf_verifier_env *env,
1583 const struct resolve_vertex *v)
1585 const struct btf_member *member;
1589 /* Before continue resolving the next_member,
1590 * ensure the last member is indeed resolved to a
1591 * type with size info.
1593 if (v->next_member) {
1594 const struct btf_type *last_member_type;
1595 const struct btf_member *last_member;
1596 u16 last_member_type_id;
1598 last_member = btf_type_member(v->t) + v->next_member - 1;
1599 last_member_type_id = last_member->type;
1600 if (WARN_ON_ONCE(!env_type_is_resolved(env,
1601 last_member_type_id)))
1604 last_member_type = btf_type_by_id(env->btf,
1605 last_member_type_id);
1606 err = btf_type_ops(last_member_type)->check_member(env, v->t,
1613 for_each_member_from(i, v->next_member, v->t, member) {
1614 u32 member_type_id = member->type;
1615 const struct btf_type *member_type = btf_type_by_id(env->btf,
1618 if (btf_type_is_void_or_null(member_type)) {
1619 btf_verifier_log_member(env, v->t, member,
1624 if (!env_type_is_resolve_sink(env, member_type) &&
1625 !env_type_is_resolved(env, member_type_id)) {
1626 env_stack_set_next_member(env, i + 1);
1627 return env_stack_push(env, member_type, member_type_id);
1630 err = btf_type_ops(member_type)->check_member(env, v->t,
1637 env_stack_pop_resolved(env, 0, 0);
1642 static void btf_struct_log(struct btf_verifier_env *env,
1643 const struct btf_type *t)
1645 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
1648 static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
1649 u32 type_id, void *data, u8 bits_offset,
1652 const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ",";
1653 const struct btf_member *member;
1657 for_each_member(i, t, member) {
1658 const struct btf_type *member_type = btf_type_by_id(btf,
1660 u32 member_offset = member->offset;
1661 u32 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
1662 u8 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
1663 const struct btf_kind_operations *ops;
1668 ops = btf_type_ops(member_type);
1669 ops->seq_show(btf, member_type, member->type,
1670 data + bytes_offset, bits8_offset, m);
1675 static struct btf_kind_operations struct_ops = {
1676 .check_meta = btf_struct_check_meta,
1677 .resolve = btf_struct_resolve,
1678 .check_member = btf_struct_check_member,
1679 .log_details = btf_struct_log,
1680 .seq_show = btf_struct_seq_show,
1683 static int btf_enum_check_member(struct btf_verifier_env *env,
1684 const struct btf_type *struct_type,
1685 const struct btf_member *member,
1686 const struct btf_type *member_type)
1688 u32 struct_bits_off = member->offset;
1689 u32 struct_size, bytes_offset;
1691 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1692 btf_verifier_log_member(env, struct_type, member,
1693 "Member is not byte aligned");
1697 struct_size = struct_type->size;
1698 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1699 if (struct_size - bytes_offset < sizeof(int)) {
1700 btf_verifier_log_member(env, struct_type, member,
1701 "Member exceeds struct_size");
1708 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
1709 const struct btf_type *t,
1712 const struct btf_enum *enums = btf_type_enum(t);
1713 struct btf *btf = env->btf;
1717 nr_enums = btf_type_vlen(t);
1718 meta_needed = nr_enums * sizeof(*enums);
1720 if (meta_left < meta_needed) {
1721 btf_verifier_log_basic(env, t,
1722 "meta_left:%u meta_needed:%u",
1723 meta_left, meta_needed);
1727 if (t->size != sizeof(int)) {
1728 btf_verifier_log_type(env, t, "Expected size:%zu",
1733 btf_verifier_log_type(env, t, NULL);
1735 for (i = 0; i < nr_enums; i++) {
1736 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
1737 btf_verifier_log(env, "\tInvalid name_offset:%u",
1742 btf_verifier_log(env, "\t%s val=%d\n",
1743 btf_name_by_offset(btf, enums[i].name_off),
1750 static void btf_enum_log(struct btf_verifier_env *env,
1751 const struct btf_type *t)
1753 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
1756 static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t,
1757 u32 type_id, void *data, u8 bits_offset,
1760 const struct btf_enum *enums = btf_type_enum(t);
1761 u32 i, nr_enums = btf_type_vlen(t);
1762 int v = *(int *)data;
1764 for (i = 0; i < nr_enums; i++) {
1765 if (v == enums[i].val) {
1767 btf_name_by_offset(btf, enums[i].name_off));
1772 seq_printf(m, "%d", v);
1775 static struct btf_kind_operations enum_ops = {
1776 .check_meta = btf_enum_check_meta,
1777 .resolve = btf_df_resolve,
1778 .check_member = btf_enum_check_member,
1779 .log_details = btf_enum_log,
1780 .seq_show = btf_enum_seq_show,
1783 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
1784 [BTF_KIND_INT] = &int_ops,
1785 [BTF_KIND_PTR] = &ptr_ops,
1786 [BTF_KIND_ARRAY] = &array_ops,
1787 [BTF_KIND_STRUCT] = &struct_ops,
1788 [BTF_KIND_UNION] = &struct_ops,
1789 [BTF_KIND_ENUM] = &enum_ops,
1790 [BTF_KIND_FWD] = &fwd_ops,
1791 [BTF_KIND_TYPEDEF] = &modifier_ops,
1792 [BTF_KIND_VOLATILE] = &modifier_ops,
1793 [BTF_KIND_CONST] = &modifier_ops,
1794 [BTF_KIND_RESTRICT] = &modifier_ops,
1797 static s32 btf_check_meta(struct btf_verifier_env *env,
1798 const struct btf_type *t,
1801 u32 saved_meta_left = meta_left;
1804 if (meta_left < sizeof(*t)) {
1805 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
1806 env->log_type_id, meta_left, sizeof(*t));
1809 meta_left -= sizeof(*t);
1811 if (t->info & ~BTF_INFO_MASK) {
1812 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
1813 env->log_type_id, t->info);
1817 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
1818 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
1819 btf_verifier_log(env, "[%u] Invalid kind:%u",
1820 env->log_type_id, BTF_INFO_KIND(t->info));
1824 if (!btf_name_offset_valid(env->btf, t->name_off)) {
1825 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
1826 env->log_type_id, t->name_off);
1830 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
1831 if (var_meta_size < 0)
1832 return var_meta_size;
1834 meta_left -= var_meta_size;
1836 return saved_meta_left - meta_left;
1839 static int btf_check_all_metas(struct btf_verifier_env *env)
1841 struct btf *btf = env->btf;
1842 struct btf_header *hdr;
1846 cur = btf->nohdr_data + hdr->type_off;
1847 end = cur + hdr->type_len;
1849 env->log_type_id = 1;
1851 struct btf_type *t = cur;
1854 meta_size = btf_check_meta(env, t, end - cur);
1858 btf_add_type(env, t);
1866 static int btf_resolve(struct btf_verifier_env *env,
1867 const struct btf_type *t, u32 type_id)
1869 const struct resolve_vertex *v;
1872 env->resolve_mode = RESOLVE_TBD;
1873 env_stack_push(env, t, type_id);
1874 while (!err && (v = env_stack_peak(env))) {
1875 env->log_type_id = v->type_id;
1876 err = btf_type_ops(v->t)->resolve(env, v);
1879 env->log_type_id = type_id;
1881 btf_verifier_log_type(env, t,
1882 "Exceeded max resolving depth:%u",
1884 else if (err == -EEXIST)
1885 btf_verifier_log_type(env, t, "Loop detected");
1890 static bool btf_resolve_valid(struct btf_verifier_env *env,
1891 const struct btf_type *t,
1894 struct btf *btf = env->btf;
1896 if (!env_type_is_resolved(env, type_id))
1899 if (btf_type_is_struct(t))
1900 return !btf->resolved_ids[type_id] &&
1901 !btf->resolved_sizes[type_id];
1903 if (btf_type_is_modifier(t) || btf_type_is_ptr(t)) {
1904 t = btf_type_id_resolve(btf, &type_id);
1905 return t && !btf_type_is_modifier(t);
1908 if (btf_type_is_array(t)) {
1909 const struct btf_array *array = btf_type_array(t);
1910 const struct btf_type *elem_type;
1911 u32 elem_type_id = array->type;
1914 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1915 return elem_type && !btf_type_is_modifier(elem_type) &&
1916 (array->nelems * elem_size ==
1917 btf->resolved_sizes[type_id]);
1923 static int btf_check_all_types(struct btf_verifier_env *env)
1925 struct btf *btf = env->btf;
1929 err = env_resolve_init(env);
1934 for (type_id = 1; type_id <= btf->nr_types; type_id++) {
1935 const struct btf_type *t = btf_type_by_id(btf, type_id);
1937 env->log_type_id = type_id;
1938 if (btf_type_needs_resolve(t) &&
1939 !env_type_is_resolved(env, type_id)) {
1940 err = btf_resolve(env, t, type_id);
1945 if (btf_type_needs_resolve(t) &&
1946 !btf_resolve_valid(env, t, type_id)) {
1947 btf_verifier_log_type(env, t, "Invalid resolve state");
1955 static int btf_parse_type_sec(struct btf_verifier_env *env)
1957 const struct btf_header *hdr = &env->btf->hdr;
1960 /* Type section must align to 4 bytes */
1961 if (hdr->type_off & (sizeof(u32) - 1)) {
1962 btf_verifier_log(env, "Unaligned type_off");
1966 if (!hdr->type_len) {
1967 btf_verifier_log(env, "No type found");
1971 err = btf_check_all_metas(env);
1975 return btf_check_all_types(env);
1978 static int btf_parse_str_sec(struct btf_verifier_env *env)
1980 const struct btf_header *hdr;
1981 struct btf *btf = env->btf;
1982 const char *start, *end;
1985 start = btf->nohdr_data + hdr->str_off;
1986 end = start + hdr->str_len;
1988 if (end != btf->data + btf->data_size) {
1989 btf_verifier_log(env, "String section is not at the end");
1993 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
1994 start[0] || end[-1]) {
1995 btf_verifier_log(env, "Invalid string section");
1999 btf->strings = start;
2004 static const size_t btf_sec_info_offset[] = {
2005 offsetof(struct btf_header, type_off),
2006 offsetof(struct btf_header, str_off),
2009 static int btf_sec_info_cmp(const void *a, const void *b)
2011 const struct btf_sec_info *x = a;
2012 const struct btf_sec_info *y = b;
2014 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
2017 static int btf_check_sec_info(struct btf_verifier_env *env,
2020 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
2021 u32 total, expected_total, i;
2022 const struct btf_header *hdr;
2023 const struct btf *btf;
2028 /* Populate the secs from hdr */
2029 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
2030 secs[i] = *(struct btf_sec_info *)((void *)hdr +
2031 btf_sec_info_offset[i]);
2033 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
2034 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
2036 /* Check for gaps and overlap among sections */
2038 expected_total = btf_data_size - hdr->hdr_len;
2039 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
2040 if (expected_total < secs[i].off) {
2041 btf_verifier_log(env, "Invalid section offset");
2044 if (total < secs[i].off) {
2046 btf_verifier_log(env, "Unsupported section found");
2049 if (total > secs[i].off) {
2050 btf_verifier_log(env, "Section overlap found");
2053 if (expected_total - total < secs[i].len) {
2054 btf_verifier_log(env,
2055 "Total section length too long");
2058 total += secs[i].len;
2061 /* There is data other than hdr and known sections */
2062 if (expected_total != total) {
2063 btf_verifier_log(env, "Unsupported section found");
2070 static int btf_parse_hdr(struct btf_verifier_env *env, void __user *btf_data,
2073 const struct btf_header *hdr;
2074 u32 hdr_len, hdr_copy;
2076 * Minimal part of the "struct btf_header" that
2077 * contains the hdr_len.
2079 struct btf_min_header {
2091 if (btf_data_size < sizeof(*min_hdr)) {
2092 btf_verifier_log(env, "hdr_len not found");
2096 if (get_user(hdr_len, &min_hdr->hdr_len))
2099 if (btf_data_size < hdr_len) {
2100 btf_verifier_log(env, "btf_header not found");
2104 err = bpf_check_uarg_tail_zero(btf_data, sizeof(btf->hdr), hdr_len);
2107 btf_verifier_log(env, "Unsupported btf_header");
2111 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
2112 if (copy_from_user(&btf->hdr, btf_data, hdr_copy))
2117 btf_verifier_log_hdr(env, btf_data_size);
2119 if (hdr->magic != BTF_MAGIC) {
2120 btf_verifier_log(env, "Invalid magic");
2124 if (hdr->version != BTF_VERSION) {
2125 btf_verifier_log(env, "Unsupported version");
2130 btf_verifier_log(env, "Unsupported flags");
2134 if (btf_data_size == hdr->hdr_len) {
2135 btf_verifier_log(env, "No data");
2139 err = btf_check_sec_info(env, btf_data_size);
2146 static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
2147 u32 log_level, char __user *log_ubuf, u32 log_size)
2149 struct btf_verifier_env *env = NULL;
2150 struct bpf_verifier_log *log;
2151 struct btf *btf = NULL;
2155 if (btf_data_size > BTF_MAX_SIZE)
2156 return ERR_PTR(-E2BIG);
2158 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
2160 return ERR_PTR(-ENOMEM);
2163 if (log_level || log_ubuf || log_size) {
2164 /* user requested verbose verifier output
2165 * and supplied buffer to store the verification trace
2167 log->level = log_level;
2168 log->ubuf = log_ubuf;
2169 log->len_total = log_size;
2171 /* log attributes have to be sane */
2172 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
2173 !log->level || !log->ubuf) {
2179 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
2186 err = btf_parse_hdr(env, btf_data, btf_data_size);
2190 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
2197 btf->data_size = btf_data_size;
2198 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
2200 if (copy_from_user(data, btf_data, btf_data_size)) {
2205 err = btf_parse_str_sec(env);
2209 err = btf_parse_type_sec(env);
2213 if (log->level && bpf_verifier_log_full(log)) {
2218 btf_verifier_env_free(env);
2219 refcount_set(&btf->refcnt, 1);
2223 btf_verifier_env_free(env);
2226 return ERR_PTR(err);
2229 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
2232 const struct btf_type *t = btf_type_by_id(btf, type_id);
2234 btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m);
2237 static int btf_release(struct inode *inode, struct file *filp)
2239 btf_put(filp->private_data);
2243 const struct file_operations btf_fops = {
2244 .release = btf_release,
2247 static int __btf_new_fd(struct btf *btf)
2249 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
2252 int btf_new_fd(const union bpf_attr *attr)
2257 btf = btf_parse(u64_to_user_ptr(attr->btf),
2258 attr->btf_size, attr->btf_log_level,
2259 u64_to_user_ptr(attr->btf_log_buf),
2260 attr->btf_log_size);
2262 return PTR_ERR(btf);
2264 ret = btf_alloc_id(btf);
2271 * The BTF ID is published to the userspace.
2272 * All BTF free must go through call_rcu() from
2273 * now on (i.e. free by calling btf_put()).
2276 ret = __btf_new_fd(btf);
2283 struct btf *btf_get_by_fd(int fd)
2291 return ERR_PTR(-EBADF);
2293 if (f.file->f_op != &btf_fops) {
2295 return ERR_PTR(-EINVAL);
2298 btf = f.file->private_data;
2299 refcount_inc(&btf->refcnt);
2305 int btf_get_info_by_fd(const struct btf *btf,
2306 const union bpf_attr *attr,
2307 union bpf_attr __user *uattr)
2309 struct bpf_btf_info __user *uinfo;
2310 struct bpf_btf_info info = {};
2311 u32 info_copy, btf_copy;
2315 uinfo = u64_to_user_ptr(attr->info.info);
2316 uinfo_len = attr->info.info_len;
2318 info_copy = min_t(u32, uinfo_len, sizeof(info));
2319 if (copy_from_user(&info, uinfo, info_copy))
2323 ubtf = u64_to_user_ptr(info.btf);
2324 btf_copy = min_t(u32, btf->data_size, info.btf_size);
2325 if (copy_to_user(ubtf, btf->data, btf_copy))
2327 info.btf_size = btf->data_size;
2329 if (copy_to_user(uinfo, &info, info_copy) ||
2330 put_user(info_copy, &uattr->info.info_len))
2336 int btf_get_fd_by_id(u32 id)
2342 btf = idr_find(&btf_idr, id);
2343 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
2344 btf = ERR_PTR(-ENOENT);
2348 return PTR_ERR(btf);
2350 fd = __btf_new_fd(btf);
2357 u32 btf_id(const struct btf *btf)