1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2018 Facebook */
4 #include <uapi/linux/btf.h>
5 #include <uapi/linux/bpf.h>
6 #include <uapi/linux/bpf_perf_event.h>
7 #include <uapi/linux/types.h>
8 #include <linux/seq_file.h>
9 #include <linux/compiler.h>
10 #include <linux/ctype.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/anon_inodes.h>
14 #include <linux/file.h>
15 #include <linux/uaccess.h>
16 #include <linux/kernel.h>
17 #include <linux/idr.h>
18 #include <linux/sort.h>
19 #include <linux/bpf_verifier.h>
20 #include <linux/btf.h>
21 #include <linux/btf_ids.h>
22 #include <linux/skmsg.h>
23 #include <linux/perf_event.h>
24 #include <linux/bsearch.h>
25 #include <linux/kobject.h>
26 #include <linux/sysfs.h>
28 #include "../tools/lib/bpf/relo_core.h"
30 /* BTF (BPF Type Format) is the meta data format which describes
31 * the data types of BPF program/map. Hence, it basically focus
32 * on the C programming language which the modern BPF is primary
37 * The BTF data is stored under the ".BTF" ELF section
41 * Each 'struct btf_type' object describes a C data type.
42 * Depending on the type it is describing, a 'struct btf_type'
43 * object may be followed by more data. F.e.
44 * To describe an array, 'struct btf_type' is followed by
47 * 'struct btf_type' and any extra data following it are
52 * The BTF type section contains a list of 'struct btf_type' objects.
53 * Each one describes a C type. Recall from the above section
54 * that a 'struct btf_type' object could be immediately followed by extra
55 * data in order to describe some particular C types.
59 * Each btf_type object is identified by a type_id. The type_id
60 * is implicitly implied by the location of the btf_type object in
61 * the BTF type section. The first one has type_id 1. The second
62 * one has type_id 2...etc. Hence, an earlier btf_type has
65 * A btf_type object may refer to another btf_type object by using
66 * type_id (i.e. the "type" in the "struct btf_type").
68 * NOTE that we cannot assume any reference-order.
69 * A btf_type object can refer to an earlier btf_type object
70 * but it can also refer to a later btf_type object.
72 * For example, to describe "const void *". A btf_type
73 * object describing "const" may refer to another btf_type
74 * object describing "void *". This type-reference is done
75 * by specifying type_id:
77 * [1] CONST (anon) type_id=2
78 * [2] PTR (anon) type_id=0
80 * The above is the btf_verifier debug log:
81 * - Each line started with "[?]" is a btf_type object
82 * - [?] is the type_id of the btf_type object.
83 * - CONST/PTR is the BTF_KIND_XXX
84 * - "(anon)" is the name of the type. It just
85 * happens that CONST and PTR has no name.
86 * - type_id=XXX is the 'u32 type' in btf_type
88 * NOTE: "void" has type_id 0
92 * The BTF string section contains the names used by the type section.
93 * Each string is referred by an "offset" from the beginning of the
96 * Each string is '\0' terminated.
98 * The first character in the string section must be '\0'
99 * which is used to mean 'anonymous'. Some btf_type may not
105 * To verify BTF data, two passes are needed.
109 * The first pass is to collect all btf_type objects to
110 * an array: "btf->types".
112 * Depending on the C type that a btf_type is describing,
113 * a btf_type may be followed by extra data. We don't know
114 * how many btf_type is there, and more importantly we don't
115 * know where each btf_type is located in the type section.
117 * Without knowing the location of each type_id, most verifications
118 * cannot be done. e.g. an earlier btf_type may refer to a later
119 * btf_type (recall the "const void *" above), so we cannot
120 * check this type-reference in the first pass.
122 * In the first pass, it still does some verifications (e.g.
123 * checking the name is a valid offset to the string section).
127 * The main focus is to resolve a btf_type that is referring
130 * We have to ensure the referring type:
131 * 1) does exist in the BTF (i.e. in btf->types[])
132 * 2) does not cause a loop:
141 * btf_type_needs_resolve() decides if a btf_type needs
144 * The needs_resolve type implements the "resolve()" ops which
145 * essentially does a DFS and detects backedge.
147 * During resolve (or DFS), different C types have different
148 * "RESOLVED" conditions.
150 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
151 * members because a member is always referring to another
152 * type. A struct's member can be treated as "RESOLVED" if
153 * it is referring to a BTF_KIND_PTR. Otherwise, the
154 * following valid C struct would be rejected:
161 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
162 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
163 * detect a pointer loop, e.g.:
164 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
166 * +-----------------------------------------+
170 #define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
171 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
172 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
173 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
174 #define BITS_ROUNDUP_BYTES(bits) \
175 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
177 #define BTF_INFO_MASK 0x9f00ffff
178 #define BTF_INT_MASK 0x0fffffff
179 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
180 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
182 /* 16MB for 64k structs and each has 16 members and
183 * a few MB spaces for the string section.
184 * The hard limit is S32_MAX.
186 #define BTF_MAX_SIZE (16 * 1024 * 1024)
188 #define for_each_member_from(i, from, struct_type, member) \
189 for (i = from, member = btf_type_member(struct_type) + from; \
190 i < btf_type_vlen(struct_type); \
193 #define for_each_vsi_from(i, from, struct_type, member) \
194 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
195 i < btf_type_vlen(struct_type); \
199 DEFINE_SPINLOCK(btf_idr_lock);
201 enum btf_kfunc_hook {
204 BTF_KFUNC_HOOK_STRUCT_OPS,
205 BTF_KFUNC_HOOK_TRACING,
206 BTF_KFUNC_HOOK_SYSCALL,
211 BTF_KFUNC_SET_MAX_CNT = 256,
212 BTF_DTOR_KFUNC_MAX_CNT = 256,
215 struct btf_kfunc_set_tab {
216 struct btf_id_set8 *sets[BTF_KFUNC_HOOK_MAX];
219 struct btf_id_dtor_kfunc_tab {
221 struct btf_id_dtor_kfunc dtors[];
226 struct btf_type **types;
231 struct btf_header hdr;
232 u32 nr_types; /* includes VOID for base BTF */
238 struct btf_kfunc_set_tab *kfunc_set_tab;
239 struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
241 /* split BTF support */
242 struct btf *base_btf;
243 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
244 u32 start_str_off; /* first string offset (0 for base BTF) */
245 char name[MODULE_NAME_LEN];
249 enum verifier_phase {
254 struct resolve_vertex {
255 const struct btf_type *t;
267 RESOLVE_TBD, /* To Be Determined */
268 RESOLVE_PTR, /* Resolving for Pointer */
269 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
274 #define MAX_RESOLVE_DEPTH 32
276 struct btf_sec_info {
281 struct btf_verifier_env {
284 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
285 struct bpf_verifier_log log;
288 enum verifier_phase phase;
289 enum resolve_mode resolve_mode;
292 static const char * const btf_kind_str[NR_BTF_KINDS] = {
293 [BTF_KIND_UNKN] = "UNKNOWN",
294 [BTF_KIND_INT] = "INT",
295 [BTF_KIND_PTR] = "PTR",
296 [BTF_KIND_ARRAY] = "ARRAY",
297 [BTF_KIND_STRUCT] = "STRUCT",
298 [BTF_KIND_UNION] = "UNION",
299 [BTF_KIND_ENUM] = "ENUM",
300 [BTF_KIND_FWD] = "FWD",
301 [BTF_KIND_TYPEDEF] = "TYPEDEF",
302 [BTF_KIND_VOLATILE] = "VOLATILE",
303 [BTF_KIND_CONST] = "CONST",
304 [BTF_KIND_RESTRICT] = "RESTRICT",
305 [BTF_KIND_FUNC] = "FUNC",
306 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
307 [BTF_KIND_VAR] = "VAR",
308 [BTF_KIND_DATASEC] = "DATASEC",
309 [BTF_KIND_FLOAT] = "FLOAT",
310 [BTF_KIND_DECL_TAG] = "DECL_TAG",
311 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
312 [BTF_KIND_ENUM64] = "ENUM64",
315 const char *btf_type_str(const struct btf_type *t)
317 return btf_kind_str[BTF_INFO_KIND(t->info)];
320 /* Chunk size we use in safe copy of data to be shown. */
321 #define BTF_SHOW_OBJ_SAFE_SIZE 32
324 * This is the maximum size of a base type value (equivalent to a
325 * 128-bit int); if we are at the end of our safe buffer and have
326 * less than 16 bytes space we can't be assured of being able
327 * to copy the next type safely, so in such cases we will initiate
330 #define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
333 #define BTF_SHOW_NAME_SIZE 80
336 * Common data to all BTF show operations. Private show functions can add
337 * their own data to a structure containing a struct btf_show and consult it
338 * in the show callback. See btf_type_show() below.
340 * One challenge with showing nested data is we want to skip 0-valued
341 * data, but in order to figure out whether a nested object is all zeros
342 * we need to walk through it. As a result, we need to make two passes
343 * when handling structs, unions and arrays; the first path simply looks
344 * for nonzero data, while the second actually does the display. The first
345 * pass is signalled by show->state.depth_check being set, and if we
346 * encounter a non-zero value we set show->state.depth_to_show to
347 * the depth at which we encountered it. When we have completed the
348 * first pass, we will know if anything needs to be displayed if
349 * depth_to_show > depth. See btf_[struct,array]_show() for the
350 * implementation of this.
352 * Another problem is we want to ensure the data for display is safe to
353 * access. To support this, the anonymous "struct {} obj" tracks the data
354 * object and our safe copy of it. We copy portions of the data needed
355 * to the object "copy" buffer, but because its size is limited to
356 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
357 * traverse larger objects for display.
359 * The various data type show functions all start with a call to
360 * btf_show_start_type() which returns a pointer to the safe copy
361 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
362 * raw data itself). btf_show_obj_safe() is responsible for
363 * using copy_from_kernel_nofault() to update the safe data if necessary
364 * as we traverse the object's data. skbuff-like semantics are
367 * - obj.head points to the start of the toplevel object for display
368 * - obj.size is the size of the toplevel object
369 * - obj.data points to the current point in the original data at
370 * which our safe data starts. obj.data will advance as we copy
371 * portions of the data.
373 * In most cases a single copy will suffice, but larger data structures
374 * such as "struct task_struct" will require many copies. The logic in
375 * btf_show_obj_safe() handles the logic that determines if a new
376 * copy_from_kernel_nofault() is needed.
380 void *target; /* target of show operation (seq file, buffer) */
381 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
382 const struct btf *btf;
383 /* below are used during iteration */
392 int status; /* non-zero for error */
393 const struct btf_type *type;
394 const struct btf_member *member;
395 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
401 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
405 struct btf_kind_operations {
406 s32 (*check_meta)(struct btf_verifier_env *env,
407 const struct btf_type *t,
409 int (*resolve)(struct btf_verifier_env *env,
410 const struct resolve_vertex *v);
411 int (*check_member)(struct btf_verifier_env *env,
412 const struct btf_type *struct_type,
413 const struct btf_member *member,
414 const struct btf_type *member_type);
415 int (*check_kflag_member)(struct btf_verifier_env *env,
416 const struct btf_type *struct_type,
417 const struct btf_member *member,
418 const struct btf_type *member_type);
419 void (*log_details)(struct btf_verifier_env *env,
420 const struct btf_type *t);
421 void (*show)(const struct btf *btf, const struct btf_type *t,
422 u32 type_id, void *data, u8 bits_offsets,
423 struct btf_show *show);
426 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
427 static struct btf_type btf_void;
429 static int btf_resolve(struct btf_verifier_env *env,
430 const struct btf_type *t, u32 type_id);
432 static int btf_func_check(struct btf_verifier_env *env,
433 const struct btf_type *t);
435 static bool btf_type_is_modifier(const struct btf_type *t)
437 /* Some of them is not strictly a C modifier
438 * but they are grouped into the same bucket
440 * A type (t) that refers to another
441 * type through t->type AND its size cannot
442 * be determined without following the t->type.
444 * ptr does not fall into this bucket
445 * because its size is always sizeof(void *).
447 switch (BTF_INFO_KIND(t->info)) {
448 case BTF_KIND_TYPEDEF:
449 case BTF_KIND_VOLATILE:
451 case BTF_KIND_RESTRICT:
452 case BTF_KIND_TYPE_TAG:
459 bool btf_type_is_void(const struct btf_type *t)
461 return t == &btf_void;
464 static bool btf_type_is_fwd(const struct btf_type *t)
466 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
469 static bool btf_type_nosize(const struct btf_type *t)
471 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
472 btf_type_is_func(t) || btf_type_is_func_proto(t);
475 static bool btf_type_nosize_or_null(const struct btf_type *t)
477 return !t || btf_type_nosize(t);
480 static bool __btf_type_is_struct(const struct btf_type *t)
482 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
485 static bool btf_type_is_array(const struct btf_type *t)
487 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
490 static bool btf_type_is_datasec(const struct btf_type *t)
492 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
495 static bool btf_type_is_decl_tag(const struct btf_type *t)
497 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
500 static bool btf_type_is_decl_tag_target(const struct btf_type *t)
502 return btf_type_is_func(t) || btf_type_is_struct(t) ||
503 btf_type_is_var(t) || btf_type_is_typedef(t);
506 u32 btf_nr_types(const struct btf *btf)
511 total += btf->nr_types;
518 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
520 const struct btf_type *t;
524 total = btf_nr_types(btf);
525 for (i = 1; i < total; i++) {
526 t = btf_type_by_id(btf, i);
527 if (BTF_INFO_KIND(t->info) != kind)
530 tname = btf_name_by_offset(btf, t->name_off);
531 if (!strcmp(tname, name))
538 static s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
544 btf = bpf_get_btf_vmlinux();
550 ret = btf_find_by_name_kind(btf, name, kind);
551 /* ret is never zero, since btf_find_by_name_kind returns
552 * positive btf_id or negative error.
560 /* If name is not found in vmlinux's BTF then search in module's BTFs */
561 spin_lock_bh(&btf_idr_lock);
562 idr_for_each_entry(&btf_idr, btf, id) {
563 if (!btf_is_module(btf))
565 /* linear search could be slow hence unlock/lock
566 * the IDR to avoiding holding it for too long
569 spin_unlock_bh(&btf_idr_lock);
570 ret = btf_find_by_name_kind(btf, name, kind);
576 spin_lock_bh(&btf_idr_lock);
578 spin_unlock_bh(&btf_idr_lock);
582 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
585 const struct btf_type *t = btf_type_by_id(btf, id);
587 while (btf_type_is_modifier(t)) {
589 t = btf_type_by_id(btf, t->type);
598 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
601 const struct btf_type *t;
603 t = btf_type_skip_modifiers(btf, id, NULL);
604 if (!btf_type_is_ptr(t))
607 return btf_type_skip_modifiers(btf, t->type, res_id);
610 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
613 const struct btf_type *ptype;
615 ptype = btf_type_resolve_ptr(btf, id, res_id);
616 if (ptype && btf_type_is_func_proto(ptype))
622 /* Types that act only as a source, not sink or intermediate
623 * type when resolving.
625 static bool btf_type_is_resolve_source_only(const struct btf_type *t)
627 return btf_type_is_var(t) ||
628 btf_type_is_decl_tag(t) ||
629 btf_type_is_datasec(t);
632 /* What types need to be resolved?
634 * btf_type_is_modifier() is an obvious one.
636 * btf_type_is_struct() because its member refers to
637 * another type (through member->type).
639 * btf_type_is_var() because the variable refers to
640 * another type. btf_type_is_datasec() holds multiple
641 * btf_type_is_var() types that need resolving.
643 * btf_type_is_array() because its element (array->type)
644 * refers to another type. Array can be thought of a
645 * special case of struct while array just has the same
646 * member-type repeated by array->nelems of times.
648 static bool btf_type_needs_resolve(const struct btf_type *t)
650 return btf_type_is_modifier(t) ||
651 btf_type_is_ptr(t) ||
652 btf_type_is_struct(t) ||
653 btf_type_is_array(t) ||
654 btf_type_is_var(t) ||
655 btf_type_is_func(t) ||
656 btf_type_is_decl_tag(t) ||
657 btf_type_is_datasec(t);
660 /* t->size can be used */
661 static bool btf_type_has_size(const struct btf_type *t)
663 switch (BTF_INFO_KIND(t->info)) {
665 case BTF_KIND_STRUCT:
668 case BTF_KIND_DATASEC:
670 case BTF_KIND_ENUM64:
677 static const char *btf_int_encoding_str(u8 encoding)
681 else if (encoding == BTF_INT_SIGNED)
683 else if (encoding == BTF_INT_CHAR)
685 else if (encoding == BTF_INT_BOOL)
691 static u32 btf_type_int(const struct btf_type *t)
693 return *(u32 *)(t + 1);
696 static const struct btf_array *btf_type_array(const struct btf_type *t)
698 return (const struct btf_array *)(t + 1);
701 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
703 return (const struct btf_enum *)(t + 1);
706 static const struct btf_var *btf_type_var(const struct btf_type *t)
708 return (const struct btf_var *)(t + 1);
711 static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
713 return (const struct btf_decl_tag *)(t + 1);
716 static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t)
718 return (const struct btf_enum64 *)(t + 1);
721 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
723 return kind_ops[BTF_INFO_KIND(t->info)];
726 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
728 if (!BTF_STR_OFFSET_VALID(offset))
731 while (offset < btf->start_str_off)
734 offset -= btf->start_str_off;
735 return offset < btf->hdr.str_len;
738 static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
740 if ((first ? !isalpha(c) :
743 ((c == '.' && !dot_ok) ||
749 static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
751 while (offset < btf->start_str_off)
754 offset -= btf->start_str_off;
755 if (offset < btf->hdr.str_len)
756 return &btf->strings[offset];
761 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
763 /* offset must be valid */
764 const char *src = btf_str_by_offset(btf, offset);
765 const char *src_limit;
767 if (!__btf_name_char_ok(*src, true, dot_ok))
770 /* set a limit on identifier length */
771 src_limit = src + KSYM_NAME_LEN;
773 while (*src && src < src_limit) {
774 if (!__btf_name_char_ok(*src, false, dot_ok))
782 /* Only C-style identifier is permitted. This can be relaxed if
785 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
787 return __btf_name_valid(btf, offset, false);
790 static bool btf_name_valid_section(const struct btf *btf, u32 offset)
792 return __btf_name_valid(btf, offset, true);
795 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
802 name = btf_str_by_offset(btf, offset);
803 return name ?: "(invalid-name-offset)";
806 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
808 return btf_str_by_offset(btf, offset);
811 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
813 while (type_id < btf->start_id)
816 type_id -= btf->start_id;
817 if (type_id >= btf->nr_types)
819 return btf->types[type_id];
821 EXPORT_SYMBOL_GPL(btf_type_by_id);
824 * Regular int is not a bit field and it must be either
825 * u8/u16/u32/u64 or __int128.
827 static bool btf_type_int_is_regular(const struct btf_type *t)
829 u8 nr_bits, nr_bytes;
832 int_data = btf_type_int(t);
833 nr_bits = BTF_INT_BITS(int_data);
834 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
835 if (BITS_PER_BYTE_MASKED(nr_bits) ||
836 BTF_INT_OFFSET(int_data) ||
837 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
838 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
839 nr_bytes != (2 * sizeof(u64)))) {
847 * Check that given struct member is a regular int with expected
850 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
851 const struct btf_member *m,
852 u32 expected_offset, u32 expected_size)
854 const struct btf_type *t;
859 t = btf_type_id_size(btf, &id, NULL);
860 if (!t || !btf_type_is_int(t))
863 int_data = btf_type_int(t);
864 nr_bits = BTF_INT_BITS(int_data);
865 if (btf_type_kflag(s)) {
866 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
867 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
869 /* if kflag set, int should be a regular int and
870 * bit offset should be at byte boundary.
872 return !bitfield_size &&
873 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
874 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
877 if (BTF_INT_OFFSET(int_data) ||
878 BITS_PER_BYTE_MASKED(m->offset) ||
879 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
880 BITS_PER_BYTE_MASKED(nr_bits) ||
881 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
887 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
888 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
891 const struct btf_type *t = btf_type_by_id(btf, id);
893 while (btf_type_is_modifier(t) &&
894 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
895 t = btf_type_by_id(btf, t->type);
901 #define BTF_SHOW_MAX_ITER 10
903 #define BTF_KIND_BIT(kind) (1ULL << kind)
906 * Populate show->state.name with type name information.
907 * Format of type name is
909 * [.member_name = ] (type_name)
911 static const char *btf_show_name(struct btf_show *show)
913 /* BTF_MAX_ITER array suffixes "[]" */
914 const char *array_suffixes = "[][][][][][][][][][]";
915 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
916 /* BTF_MAX_ITER pointer suffixes "*" */
917 const char *ptr_suffixes = "**********";
918 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
919 const char *name = NULL, *prefix = "", *parens = "";
920 const struct btf_member *m = show->state.member;
921 const struct btf_type *t;
922 const struct btf_array *array;
923 u32 id = show->state.type_id;
924 const char *member = NULL;
925 bool show_member = false;
929 show->state.name[0] = '\0';
932 * Don't show type name if we're showing an array member;
933 * in that case we show the array type so don't need to repeat
934 * ourselves for each member.
936 if (show->state.array_member)
939 /* Retrieve member name, if any. */
941 member = btf_name_by_offset(show->btf, m->name_off);
942 show_member = strlen(member) > 0;
947 * Start with type_id, as we have resolved the struct btf_type *
948 * via btf_modifier_show() past the parent typedef to the child
949 * struct, int etc it is defined as. In such cases, the type_id
950 * still represents the starting type while the struct btf_type *
951 * in our show->state points at the resolved type of the typedef.
953 t = btf_type_by_id(show->btf, id);
958 * The goal here is to build up the right number of pointer and
959 * array suffixes while ensuring the type name for a typedef
960 * is represented. Along the way we accumulate a list of
961 * BTF kinds we have encountered, since these will inform later
962 * display; for example, pointer types will not require an
963 * opening "{" for struct, we will just display the pointer value.
965 * We also want to accumulate the right number of pointer or array
966 * indices in the format string while iterating until we get to
967 * the typedef/pointee/array member target type.
969 * We start by pointing at the end of pointer and array suffix
970 * strings; as we accumulate pointers and arrays we move the pointer
971 * or array string backwards so it will show the expected number of
972 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
973 * and/or arrays and typedefs are supported as a precaution.
975 * We also want to get typedef name while proceeding to resolve
976 * type it points to so that we can add parentheses if it is a
977 * "typedef struct" etc.
979 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
981 switch (BTF_INFO_KIND(t->info)) {
982 case BTF_KIND_TYPEDEF:
984 name = btf_name_by_offset(show->btf,
986 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
990 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
994 array = btf_type_array(t);
995 if (array_suffix > array_suffixes)
1000 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
1001 if (ptr_suffix > ptr_suffixes)
1011 t = btf_type_skip_qualifiers(show->btf, id);
1013 /* We may not be able to represent this type; bail to be safe */
1014 if (i == BTF_SHOW_MAX_ITER)
1018 name = btf_name_by_offset(show->btf, t->name_off);
1020 switch (BTF_INFO_KIND(t->info)) {
1021 case BTF_KIND_STRUCT:
1022 case BTF_KIND_UNION:
1023 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1025 /* if it's an array of struct/union, parens is already set */
1026 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1030 case BTF_KIND_ENUM64:
1037 /* pointer does not require parens */
1038 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1040 /* typedef does not require struct/union/enum prefix */
1041 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1047 /* Even if we don't want type name info, we want parentheses etc */
1048 if (show->flags & BTF_SHOW_NONAME)
1049 snprintf(show->state.name, sizeof(show->state.name), "%s",
1052 snprintf(show->state.name, sizeof(show->state.name),
1053 "%s%s%s(%s%s%s%s%s%s)%s",
1054 /* first 3 strings comprise ".member = " */
1055 show_member ? "." : "",
1056 show_member ? member : "",
1057 show_member ? " = " : "",
1058 /* ...next is our prefix (struct, enum, etc) */
1060 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1061 /* ...this is the type name itself */
1063 /* ...suffixed by the appropriate '*', '[]' suffixes */
1064 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1065 array_suffix, parens);
1067 return show->state.name;
1070 static const char *__btf_show_indent(struct btf_show *show)
1072 const char *indents = " ";
1073 const char *indent = &indents[strlen(indents)];
1075 if ((indent - show->state.depth) >= indents)
1076 return indent - show->state.depth;
1080 static const char *btf_show_indent(struct btf_show *show)
1082 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1085 static const char *btf_show_newline(struct btf_show *show)
1087 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1090 static const char *btf_show_delim(struct btf_show *show)
1092 if (show->state.depth == 0)
1095 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1096 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1102 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1106 if (!show->state.depth_check) {
1107 va_start(args, fmt);
1108 show->showfn(show, fmt, args);
1113 /* Macros are used here as btf_show_type_value[s]() prepends and appends
1114 * format specifiers to the format specifier passed in; these do the work of
1115 * adding indentation, delimiters etc while the caller simply has to specify
1116 * the type value(s) in the format specifier + value(s).
1118 #define btf_show_type_value(show, fmt, value) \
1120 if ((value) != (__typeof__(value))0 || \
1121 (show->flags & BTF_SHOW_ZERO) || \
1122 show->state.depth == 0) { \
1123 btf_show(show, "%s%s" fmt "%s%s", \
1124 btf_show_indent(show), \
1125 btf_show_name(show), \
1126 value, btf_show_delim(show), \
1127 btf_show_newline(show)); \
1128 if (show->state.depth > show->state.depth_to_show) \
1129 show->state.depth_to_show = show->state.depth; \
1133 #define btf_show_type_values(show, fmt, ...) \
1135 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1136 btf_show_name(show), \
1137 __VA_ARGS__, btf_show_delim(show), \
1138 btf_show_newline(show)); \
1139 if (show->state.depth > show->state.depth_to_show) \
1140 show->state.depth_to_show = show->state.depth; \
1143 /* How much is left to copy to safe buffer after @data? */
1144 static int btf_show_obj_size_left(struct btf_show *show, void *data)
1146 return show->obj.head + show->obj.size - data;
1149 /* Is object pointed to by @data of @size already copied to our safe buffer? */
1150 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1152 return data >= show->obj.data &&
1153 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1157 * If object pointed to by @data of @size falls within our safe buffer, return
1158 * the equivalent pointer to the same safe data. Assumes
1159 * copy_from_kernel_nofault() has already happened and our safe buffer is
1162 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1164 if (btf_show_obj_is_safe(show, data, size))
1165 return show->obj.safe + (data - show->obj.data);
1170 * Return a safe-to-access version of data pointed to by @data.
1171 * We do this by copying the relevant amount of information
1172 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1174 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1175 * safe copy is needed.
1177 * Otherwise we need to determine if we have the required amount
1178 * of data (determined by the @data pointer and the size of the
1179 * largest base type we can encounter (represented by
1180 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1181 * that we will be able to print some of the current object,
1182 * and if more is needed a copy will be triggered.
1183 * Some objects such as structs will not fit into the buffer;
1184 * in such cases additional copies when we iterate over their
1185 * members may be needed.
1187 * btf_show_obj_safe() is used to return a safe buffer for
1188 * btf_show_start_type(); this ensures that as we recurse into
1189 * nested types we always have safe data for the given type.
1190 * This approach is somewhat wasteful; it's possible for example
1191 * that when iterating over a large union we'll end up copying the
1192 * same data repeatedly, but the goal is safety not performance.
1193 * We use stack data as opposed to per-CPU buffers because the
1194 * iteration over a type can take some time, and preemption handling
1195 * would greatly complicate use of the safe buffer.
1197 static void *btf_show_obj_safe(struct btf_show *show,
1198 const struct btf_type *t,
1201 const struct btf_type *rt;
1202 int size_left, size;
1205 if (show->flags & BTF_SHOW_UNSAFE)
1208 rt = btf_resolve_size(show->btf, t, &size);
1210 show->state.status = PTR_ERR(rt);
1215 * Is this toplevel object? If so, set total object size and
1216 * initialize pointers. Otherwise check if we still fall within
1217 * our safe object data.
1219 if (show->state.depth == 0) {
1220 show->obj.size = size;
1221 show->obj.head = data;
1224 * If the size of the current object is > our remaining
1225 * safe buffer we _may_ need to do a new copy. However
1226 * consider the case of a nested struct; it's size pushes
1227 * us over the safe buffer limit, but showing any individual
1228 * struct members does not. In such cases, we don't need
1229 * to initiate a fresh copy yet; however we definitely need
1230 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1231 * in our buffer, regardless of the current object size.
1232 * The logic here is that as we resolve types we will
1233 * hit a base type at some point, and we need to be sure
1234 * the next chunk of data is safely available to display
1235 * that type info safely. We cannot rely on the size of
1236 * the current object here because it may be much larger
1237 * than our current buffer (e.g. task_struct is 8k).
1238 * All we want to do here is ensure that we can print the
1239 * next basic type, which we can if either
1240 * - the current type size is within the safe buffer; or
1241 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1244 safe = __btf_show_obj_safe(show, data,
1246 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1250 * We need a new copy to our safe object, either because we haven't
1251 * yet copied and are initializing safe data, or because the data
1252 * we want falls outside the boundaries of the safe object.
1255 size_left = btf_show_obj_size_left(show, data);
1256 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1257 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1258 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1260 if (!show->state.status) {
1261 show->obj.data = data;
1262 safe = show->obj.safe;
1270 * Set the type we are starting to show and return a safe data pointer
1271 * to be used for showing the associated data.
1273 static void *btf_show_start_type(struct btf_show *show,
1274 const struct btf_type *t,
1275 u32 type_id, void *data)
1277 show->state.type = t;
1278 show->state.type_id = type_id;
1279 show->state.name[0] = '\0';
1281 return btf_show_obj_safe(show, t, data);
1284 static void btf_show_end_type(struct btf_show *show)
1286 show->state.type = NULL;
1287 show->state.type_id = 0;
1288 show->state.name[0] = '\0';
1291 static void *btf_show_start_aggr_type(struct btf_show *show,
1292 const struct btf_type *t,
1293 u32 type_id, void *data)
1295 void *safe_data = btf_show_start_type(show, t, type_id, data);
1300 btf_show(show, "%s%s%s", btf_show_indent(show),
1301 btf_show_name(show),
1302 btf_show_newline(show));
1303 show->state.depth++;
1307 static void btf_show_end_aggr_type(struct btf_show *show,
1310 show->state.depth--;
1311 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1312 btf_show_delim(show), btf_show_newline(show));
1313 btf_show_end_type(show);
1316 static void btf_show_start_member(struct btf_show *show,
1317 const struct btf_member *m)
1319 show->state.member = m;
1322 static void btf_show_start_array_member(struct btf_show *show)
1324 show->state.array_member = 1;
1325 btf_show_start_member(show, NULL);
1328 static void btf_show_end_member(struct btf_show *show)
1330 show->state.member = NULL;
1333 static void btf_show_end_array_member(struct btf_show *show)
1335 show->state.array_member = 0;
1336 btf_show_end_member(show);
1339 static void *btf_show_start_array_type(struct btf_show *show,
1340 const struct btf_type *t,
1345 show->state.array_encoding = array_encoding;
1346 show->state.array_terminated = 0;
1347 return btf_show_start_aggr_type(show, t, type_id, data);
1350 static void btf_show_end_array_type(struct btf_show *show)
1352 show->state.array_encoding = 0;
1353 show->state.array_terminated = 0;
1354 btf_show_end_aggr_type(show, "]");
1357 static void *btf_show_start_struct_type(struct btf_show *show,
1358 const struct btf_type *t,
1362 return btf_show_start_aggr_type(show, t, type_id, data);
1365 static void btf_show_end_struct_type(struct btf_show *show)
1367 btf_show_end_aggr_type(show, "}");
1370 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1371 const char *fmt, ...)
1375 va_start(args, fmt);
1376 bpf_verifier_vlog(log, fmt, args);
1380 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1381 const char *fmt, ...)
1383 struct bpf_verifier_log *log = &env->log;
1386 if (!bpf_verifier_log_needed(log))
1389 va_start(args, fmt);
1390 bpf_verifier_vlog(log, fmt, args);
1394 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1395 const struct btf_type *t,
1397 const char *fmt, ...)
1399 struct bpf_verifier_log *log = &env->log;
1400 struct btf *btf = env->btf;
1403 if (!bpf_verifier_log_needed(log))
1406 /* btf verifier prints all types it is processing via
1407 * btf_verifier_log_type(..., fmt = NULL).
1408 * Skip those prints for in-kernel BTF verification.
1410 if (log->level == BPF_LOG_KERNEL && !fmt)
1413 __btf_verifier_log(log, "[%u] %s %s%s",
1416 __btf_name_by_offset(btf, t->name_off),
1417 log_details ? " " : "");
1420 btf_type_ops(t)->log_details(env, t);
1423 __btf_verifier_log(log, " ");
1424 va_start(args, fmt);
1425 bpf_verifier_vlog(log, fmt, args);
1429 __btf_verifier_log(log, "\n");
1432 #define btf_verifier_log_type(env, t, ...) \
1433 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1434 #define btf_verifier_log_basic(env, t, ...) \
1435 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1438 static void btf_verifier_log_member(struct btf_verifier_env *env,
1439 const struct btf_type *struct_type,
1440 const struct btf_member *member,
1441 const char *fmt, ...)
1443 struct bpf_verifier_log *log = &env->log;
1444 struct btf *btf = env->btf;
1447 if (!bpf_verifier_log_needed(log))
1450 if (log->level == BPF_LOG_KERNEL && !fmt)
1452 /* The CHECK_META phase already did a btf dump.
1454 * If member is logged again, it must hit an error in
1455 * parsing this member. It is useful to print out which
1456 * struct this member belongs to.
1458 if (env->phase != CHECK_META)
1459 btf_verifier_log_type(env, struct_type, NULL);
1461 if (btf_type_kflag(struct_type))
1462 __btf_verifier_log(log,
1463 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1464 __btf_name_by_offset(btf, member->name_off),
1466 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1467 BTF_MEMBER_BIT_OFFSET(member->offset));
1469 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1470 __btf_name_by_offset(btf, member->name_off),
1471 member->type, member->offset);
1474 __btf_verifier_log(log, " ");
1475 va_start(args, fmt);
1476 bpf_verifier_vlog(log, fmt, args);
1480 __btf_verifier_log(log, "\n");
1484 static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1485 const struct btf_type *datasec_type,
1486 const struct btf_var_secinfo *vsi,
1487 const char *fmt, ...)
1489 struct bpf_verifier_log *log = &env->log;
1492 if (!bpf_verifier_log_needed(log))
1494 if (log->level == BPF_LOG_KERNEL && !fmt)
1496 if (env->phase != CHECK_META)
1497 btf_verifier_log_type(env, datasec_type, NULL);
1499 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1500 vsi->type, vsi->offset, vsi->size);
1502 __btf_verifier_log(log, " ");
1503 va_start(args, fmt);
1504 bpf_verifier_vlog(log, fmt, args);
1508 __btf_verifier_log(log, "\n");
1511 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1514 struct bpf_verifier_log *log = &env->log;
1515 const struct btf *btf = env->btf;
1516 const struct btf_header *hdr;
1518 if (!bpf_verifier_log_needed(log))
1521 if (log->level == BPF_LOG_KERNEL)
1524 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1525 __btf_verifier_log(log, "version: %u\n", hdr->version);
1526 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1527 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1528 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1529 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1530 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1531 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1532 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1535 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1537 struct btf *btf = env->btf;
1539 if (btf->types_size == btf->nr_types) {
1540 /* Expand 'types' array */
1542 struct btf_type **new_types;
1543 u32 expand_by, new_size;
1545 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1546 btf_verifier_log(env, "Exceeded max num of types");
1550 expand_by = max_t(u32, btf->types_size >> 2, 16);
1551 new_size = min_t(u32, BTF_MAX_TYPE,
1552 btf->types_size + expand_by);
1554 new_types = kvcalloc(new_size, sizeof(*new_types),
1555 GFP_KERNEL | __GFP_NOWARN);
1559 if (btf->nr_types == 0) {
1560 if (!btf->base_btf) {
1561 /* lazily init VOID type */
1562 new_types[0] = &btf_void;
1566 memcpy(new_types, btf->types,
1567 sizeof(*btf->types) * btf->nr_types);
1571 btf->types = new_types;
1572 btf->types_size = new_size;
1575 btf->types[btf->nr_types++] = t;
1580 static int btf_alloc_id(struct btf *btf)
1584 idr_preload(GFP_KERNEL);
1585 spin_lock_bh(&btf_idr_lock);
1586 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1589 spin_unlock_bh(&btf_idr_lock);
1592 if (WARN_ON_ONCE(!id))
1595 return id > 0 ? 0 : id;
1598 static void btf_free_id(struct btf *btf)
1600 unsigned long flags;
1603 * In map-in-map, calling map_delete_elem() on outer
1604 * map will call bpf_map_put on the inner map.
1605 * It will then eventually call btf_free_id()
1606 * on the inner map. Some of the map_delete_elem()
1607 * implementation may have irq disabled, so
1608 * we need to use the _irqsave() version instead
1609 * of the _bh() version.
1611 spin_lock_irqsave(&btf_idr_lock, flags);
1612 idr_remove(&btf_idr, btf->id);
1613 spin_unlock_irqrestore(&btf_idr_lock, flags);
1616 static void btf_free_kfunc_set_tab(struct btf *btf)
1618 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1623 /* For module BTF, we directly assign the sets being registered, so
1624 * there is nothing to free except kfunc_set_tab.
1626 if (btf_is_module(btf))
1628 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++)
1629 kfree(tab->sets[hook]);
1632 btf->kfunc_set_tab = NULL;
1635 static void btf_free_dtor_kfunc_tab(struct btf *btf)
1637 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
1642 btf->dtor_kfunc_tab = NULL;
1645 static void btf_free(struct btf *btf)
1647 btf_free_dtor_kfunc_tab(btf);
1648 btf_free_kfunc_set_tab(btf);
1650 kvfree(btf->resolved_sizes);
1651 kvfree(btf->resolved_ids);
1656 static void btf_free_rcu(struct rcu_head *rcu)
1658 struct btf *btf = container_of(rcu, struct btf, rcu);
1663 void btf_get(struct btf *btf)
1665 refcount_inc(&btf->refcnt);
1668 void btf_put(struct btf *btf)
1670 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1672 call_rcu(&btf->rcu, btf_free_rcu);
1676 static int env_resolve_init(struct btf_verifier_env *env)
1678 struct btf *btf = env->btf;
1679 u32 nr_types = btf->nr_types;
1680 u32 *resolved_sizes = NULL;
1681 u32 *resolved_ids = NULL;
1682 u8 *visit_states = NULL;
1684 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1685 GFP_KERNEL | __GFP_NOWARN);
1686 if (!resolved_sizes)
1689 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1690 GFP_KERNEL | __GFP_NOWARN);
1694 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1695 GFP_KERNEL | __GFP_NOWARN);
1699 btf->resolved_sizes = resolved_sizes;
1700 btf->resolved_ids = resolved_ids;
1701 env->visit_states = visit_states;
1706 kvfree(resolved_sizes);
1707 kvfree(resolved_ids);
1708 kvfree(visit_states);
1712 static void btf_verifier_env_free(struct btf_verifier_env *env)
1714 kvfree(env->visit_states);
1718 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1719 const struct btf_type *next_type)
1721 switch (env->resolve_mode) {
1723 /* int, enum or void is a sink */
1724 return !btf_type_needs_resolve(next_type);
1726 /* int, enum, void, struct, array, func or func_proto is a sink
1729 return !btf_type_is_modifier(next_type) &&
1730 !btf_type_is_ptr(next_type);
1731 case RESOLVE_STRUCT_OR_ARRAY:
1732 /* int, enum, void, ptr, func or func_proto is a sink
1733 * for struct and array
1735 return !btf_type_is_modifier(next_type) &&
1736 !btf_type_is_array(next_type) &&
1737 !btf_type_is_struct(next_type);
1743 static bool env_type_is_resolved(const struct btf_verifier_env *env,
1746 /* base BTF types should be resolved by now */
1747 if (type_id < env->btf->start_id)
1750 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1753 static int env_stack_push(struct btf_verifier_env *env,
1754 const struct btf_type *t, u32 type_id)
1756 const struct btf *btf = env->btf;
1757 struct resolve_vertex *v;
1759 if (env->top_stack == MAX_RESOLVE_DEPTH)
1762 if (type_id < btf->start_id
1763 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1766 env->visit_states[type_id - btf->start_id] = VISITED;
1768 v = &env->stack[env->top_stack++];
1770 v->type_id = type_id;
1773 if (env->resolve_mode == RESOLVE_TBD) {
1774 if (btf_type_is_ptr(t))
1775 env->resolve_mode = RESOLVE_PTR;
1776 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1777 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1783 static void env_stack_set_next_member(struct btf_verifier_env *env,
1786 env->stack[env->top_stack - 1].next_member = next_member;
1789 static void env_stack_pop_resolved(struct btf_verifier_env *env,
1790 u32 resolved_type_id,
1793 u32 type_id = env->stack[--(env->top_stack)].type_id;
1794 struct btf *btf = env->btf;
1796 type_id -= btf->start_id; /* adjust to local type id */
1797 btf->resolved_sizes[type_id] = resolved_size;
1798 btf->resolved_ids[type_id] = resolved_type_id;
1799 env->visit_states[type_id] = RESOLVED;
1802 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1804 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1807 /* Resolve the size of a passed-in "type"
1809 * type: is an array (e.g. u32 array[x][y])
1810 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1811 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1812 * corresponds to the return type.
1814 * *elem_id: id of u32
1815 * *total_nelems: (x * y). Hence, individual elem size is
1816 * (*type_size / *total_nelems)
1817 * *type_id: id of type if it's changed within the function, 0 if not
1819 * type: is not an array (e.g. const struct X)
1820 * return type: type "struct X"
1821 * *type_size: sizeof(struct X)
1822 * *elem_type: same as return type ("struct X")
1825 * *type_id: id of type if it's changed within the function, 0 if not
1827 static const struct btf_type *
1828 __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1829 u32 *type_size, const struct btf_type **elem_type,
1830 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1832 const struct btf_type *array_type = NULL;
1833 const struct btf_array *array = NULL;
1834 u32 i, size, nelems = 1, id = 0;
1836 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1837 switch (BTF_INFO_KIND(type->info)) {
1838 /* type->size can be used */
1840 case BTF_KIND_STRUCT:
1841 case BTF_KIND_UNION:
1843 case BTF_KIND_FLOAT:
1844 case BTF_KIND_ENUM64:
1849 size = sizeof(void *);
1853 case BTF_KIND_TYPEDEF:
1854 case BTF_KIND_VOLATILE:
1855 case BTF_KIND_CONST:
1856 case BTF_KIND_RESTRICT:
1857 case BTF_KIND_TYPE_TAG:
1859 type = btf_type_by_id(btf, type->type);
1862 case BTF_KIND_ARRAY:
1865 array = btf_type_array(type);
1866 if (nelems && array->nelems > U32_MAX / nelems)
1867 return ERR_PTR(-EINVAL);
1868 nelems *= array->nelems;
1869 type = btf_type_by_id(btf, array->type);
1872 /* type without size */
1874 return ERR_PTR(-EINVAL);
1878 return ERR_PTR(-EINVAL);
1881 if (nelems && size > U32_MAX / nelems)
1882 return ERR_PTR(-EINVAL);
1884 *type_size = nelems * size;
1886 *total_nelems = nelems;
1890 *elem_id = array ? array->type : 0;
1894 return array_type ? : type;
1897 const struct btf_type *
1898 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1901 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1904 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1906 while (type_id < btf->start_id)
1907 btf = btf->base_btf;
1909 return btf->resolved_ids[type_id - btf->start_id];
1912 /* The input param "type_id" must point to a needs_resolve type */
1913 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1916 *type_id = btf_resolved_type_id(btf, *type_id);
1917 return btf_type_by_id(btf, *type_id);
1920 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1922 while (type_id < btf->start_id)
1923 btf = btf->base_btf;
1925 return btf->resolved_sizes[type_id - btf->start_id];
1928 const struct btf_type *btf_type_id_size(const struct btf *btf,
1929 u32 *type_id, u32 *ret_size)
1931 const struct btf_type *size_type;
1932 u32 size_type_id = *type_id;
1935 size_type = btf_type_by_id(btf, size_type_id);
1936 if (btf_type_nosize_or_null(size_type))
1939 if (btf_type_has_size(size_type)) {
1940 size = size_type->size;
1941 } else if (btf_type_is_array(size_type)) {
1942 size = btf_resolved_type_size(btf, size_type_id);
1943 } else if (btf_type_is_ptr(size_type)) {
1944 size = sizeof(void *);
1946 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1947 !btf_type_is_var(size_type)))
1950 size_type_id = btf_resolved_type_id(btf, size_type_id);
1951 size_type = btf_type_by_id(btf, size_type_id);
1952 if (btf_type_nosize_or_null(size_type))
1954 else if (btf_type_has_size(size_type))
1955 size = size_type->size;
1956 else if (btf_type_is_array(size_type))
1957 size = btf_resolved_type_size(btf, size_type_id);
1958 else if (btf_type_is_ptr(size_type))
1959 size = sizeof(void *);
1964 *type_id = size_type_id;
1971 static int btf_df_check_member(struct btf_verifier_env *env,
1972 const struct btf_type *struct_type,
1973 const struct btf_member *member,
1974 const struct btf_type *member_type)
1976 btf_verifier_log_basic(env, struct_type,
1977 "Unsupported check_member");
1981 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1982 const struct btf_type *struct_type,
1983 const struct btf_member *member,
1984 const struct btf_type *member_type)
1986 btf_verifier_log_basic(env, struct_type,
1987 "Unsupported check_kflag_member");
1991 /* Used for ptr, array struct/union and float type members.
1992 * int, enum and modifier types have their specific callback functions.
1994 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1995 const struct btf_type *struct_type,
1996 const struct btf_member *member,
1997 const struct btf_type *member_type)
1999 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
2000 btf_verifier_log_member(env, struct_type, member,
2001 "Invalid member bitfield_size");
2005 /* bitfield size is 0, so member->offset represents bit offset only.
2006 * It is safe to call non kflag check_member variants.
2008 return btf_type_ops(member_type)->check_member(env, struct_type,
2013 static int btf_df_resolve(struct btf_verifier_env *env,
2014 const struct resolve_vertex *v)
2016 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
2020 static void btf_df_show(const struct btf *btf, const struct btf_type *t,
2021 u32 type_id, void *data, u8 bits_offsets,
2022 struct btf_show *show)
2024 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
2027 static int btf_int_check_member(struct btf_verifier_env *env,
2028 const struct btf_type *struct_type,
2029 const struct btf_member *member,
2030 const struct btf_type *member_type)
2032 u32 int_data = btf_type_int(member_type);
2033 u32 struct_bits_off = member->offset;
2034 u32 struct_size = struct_type->size;
2038 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2039 btf_verifier_log_member(env, struct_type, member,
2040 "bits_offset exceeds U32_MAX");
2044 struct_bits_off += BTF_INT_OFFSET(int_data);
2045 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2046 nr_copy_bits = BTF_INT_BITS(int_data) +
2047 BITS_PER_BYTE_MASKED(struct_bits_off);
2049 if (nr_copy_bits > BITS_PER_U128) {
2050 btf_verifier_log_member(env, struct_type, member,
2051 "nr_copy_bits exceeds 128");
2055 if (struct_size < bytes_offset ||
2056 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2057 btf_verifier_log_member(env, struct_type, member,
2058 "Member exceeds struct_size");
2065 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2066 const struct btf_type *struct_type,
2067 const struct btf_member *member,
2068 const struct btf_type *member_type)
2070 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2071 u32 int_data = btf_type_int(member_type);
2072 u32 struct_size = struct_type->size;
2075 /* a regular int type is required for the kflag int member */
2076 if (!btf_type_int_is_regular(member_type)) {
2077 btf_verifier_log_member(env, struct_type, member,
2078 "Invalid member base type");
2082 /* check sanity of bitfield size */
2083 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2084 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2085 nr_int_data_bits = BTF_INT_BITS(int_data);
2087 /* Not a bitfield member, member offset must be at byte
2090 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2091 btf_verifier_log_member(env, struct_type, member,
2092 "Invalid member offset");
2096 nr_bits = nr_int_data_bits;
2097 } else if (nr_bits > nr_int_data_bits) {
2098 btf_verifier_log_member(env, struct_type, member,
2099 "Invalid member bitfield_size");
2103 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2104 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2105 if (nr_copy_bits > BITS_PER_U128) {
2106 btf_verifier_log_member(env, struct_type, member,
2107 "nr_copy_bits exceeds 128");
2111 if (struct_size < bytes_offset ||
2112 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2113 btf_verifier_log_member(env, struct_type, member,
2114 "Member exceeds struct_size");
2121 static s32 btf_int_check_meta(struct btf_verifier_env *env,
2122 const struct btf_type *t,
2125 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2128 if (meta_left < meta_needed) {
2129 btf_verifier_log_basic(env, t,
2130 "meta_left:%u meta_needed:%u",
2131 meta_left, meta_needed);
2135 if (btf_type_vlen(t)) {
2136 btf_verifier_log_type(env, t, "vlen != 0");
2140 if (btf_type_kflag(t)) {
2141 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2145 int_data = btf_type_int(t);
2146 if (int_data & ~BTF_INT_MASK) {
2147 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2152 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2154 if (nr_bits > BITS_PER_U128) {
2155 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2160 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2161 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2166 * Only one of the encoding bits is allowed and it
2167 * should be sufficient for the pretty print purpose (i.e. decoding).
2168 * Multiple bits can be allowed later if it is found
2169 * to be insufficient.
2171 encoding = BTF_INT_ENCODING(int_data);
2173 encoding != BTF_INT_SIGNED &&
2174 encoding != BTF_INT_CHAR &&
2175 encoding != BTF_INT_BOOL) {
2176 btf_verifier_log_type(env, t, "Unsupported encoding");
2180 btf_verifier_log_type(env, t, NULL);
2185 static void btf_int_log(struct btf_verifier_env *env,
2186 const struct btf_type *t)
2188 int int_data = btf_type_int(t);
2190 btf_verifier_log(env,
2191 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2192 t->size, BTF_INT_OFFSET(int_data),
2193 BTF_INT_BITS(int_data),
2194 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2197 static void btf_int128_print(struct btf_show *show, void *data)
2199 /* data points to a __int128 number.
2201 * int128_num = *(__int128 *)data;
2202 * The below formulas shows what upper_num and lower_num represents:
2203 * upper_num = int128_num >> 64;
2204 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2206 u64 upper_num, lower_num;
2208 #ifdef __BIG_ENDIAN_BITFIELD
2209 upper_num = *(u64 *)data;
2210 lower_num = *(u64 *)(data + 8);
2212 upper_num = *(u64 *)(data + 8);
2213 lower_num = *(u64 *)data;
2216 btf_show_type_value(show, "0x%llx", lower_num);
2218 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2222 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2223 u16 right_shift_bits)
2225 u64 upper_num, lower_num;
2227 #ifdef __BIG_ENDIAN_BITFIELD
2228 upper_num = print_num[0];
2229 lower_num = print_num[1];
2231 upper_num = print_num[1];
2232 lower_num = print_num[0];
2235 /* shake out un-needed bits by shift/or operations */
2236 if (left_shift_bits >= 64) {
2237 upper_num = lower_num << (left_shift_bits - 64);
2240 upper_num = (upper_num << left_shift_bits) |
2241 (lower_num >> (64 - left_shift_bits));
2242 lower_num = lower_num << left_shift_bits;
2245 if (right_shift_bits >= 64) {
2246 lower_num = upper_num >> (right_shift_bits - 64);
2249 lower_num = (lower_num >> right_shift_bits) |
2250 (upper_num << (64 - right_shift_bits));
2251 upper_num = upper_num >> right_shift_bits;
2254 #ifdef __BIG_ENDIAN_BITFIELD
2255 print_num[0] = upper_num;
2256 print_num[1] = lower_num;
2258 print_num[0] = lower_num;
2259 print_num[1] = upper_num;
2263 static void btf_bitfield_show(void *data, u8 bits_offset,
2264 u8 nr_bits, struct btf_show *show)
2266 u16 left_shift_bits, right_shift_bits;
2269 u64 print_num[2] = {};
2271 nr_copy_bits = nr_bits + bits_offset;
2272 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2274 memcpy(print_num, data, nr_copy_bytes);
2276 #ifdef __BIG_ENDIAN_BITFIELD
2277 left_shift_bits = bits_offset;
2279 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2281 right_shift_bits = BITS_PER_U128 - nr_bits;
2283 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2284 btf_int128_print(show, print_num);
2288 static void btf_int_bits_show(const struct btf *btf,
2289 const struct btf_type *t,
2290 void *data, u8 bits_offset,
2291 struct btf_show *show)
2293 u32 int_data = btf_type_int(t);
2294 u8 nr_bits = BTF_INT_BITS(int_data);
2295 u8 total_bits_offset;
2298 * bits_offset is at most 7.
2299 * BTF_INT_OFFSET() cannot exceed 128 bits.
2301 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2302 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2303 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2304 btf_bitfield_show(data, bits_offset, nr_bits, show);
2307 static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2308 u32 type_id, void *data, u8 bits_offset,
2309 struct btf_show *show)
2311 u32 int_data = btf_type_int(t);
2312 u8 encoding = BTF_INT_ENCODING(int_data);
2313 bool sign = encoding & BTF_INT_SIGNED;
2314 u8 nr_bits = BTF_INT_BITS(int_data);
2317 safe_data = btf_show_start_type(show, t, type_id, data);
2321 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2322 BITS_PER_BYTE_MASKED(nr_bits)) {
2323 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2329 btf_int128_print(show, safe_data);
2333 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2335 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2339 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2341 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2345 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2347 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2350 if (show->state.array_encoding == BTF_INT_CHAR) {
2351 /* check for null terminator */
2352 if (show->state.array_terminated)
2354 if (*(char *)data == '\0') {
2355 show->state.array_terminated = 1;
2358 if (isprint(*(char *)data)) {
2359 btf_show_type_value(show, "'%c'",
2360 *(char *)safe_data);
2365 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2367 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2370 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2374 btf_show_end_type(show);
2377 static const struct btf_kind_operations int_ops = {
2378 .check_meta = btf_int_check_meta,
2379 .resolve = btf_df_resolve,
2380 .check_member = btf_int_check_member,
2381 .check_kflag_member = btf_int_check_kflag_member,
2382 .log_details = btf_int_log,
2383 .show = btf_int_show,
2386 static int btf_modifier_check_member(struct btf_verifier_env *env,
2387 const struct btf_type *struct_type,
2388 const struct btf_member *member,
2389 const struct btf_type *member_type)
2391 const struct btf_type *resolved_type;
2392 u32 resolved_type_id = member->type;
2393 struct btf_member resolved_member;
2394 struct btf *btf = env->btf;
2396 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2397 if (!resolved_type) {
2398 btf_verifier_log_member(env, struct_type, member,
2403 resolved_member = *member;
2404 resolved_member.type = resolved_type_id;
2406 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2411 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2412 const struct btf_type *struct_type,
2413 const struct btf_member *member,
2414 const struct btf_type *member_type)
2416 const struct btf_type *resolved_type;
2417 u32 resolved_type_id = member->type;
2418 struct btf_member resolved_member;
2419 struct btf *btf = env->btf;
2421 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2422 if (!resolved_type) {
2423 btf_verifier_log_member(env, struct_type, member,
2428 resolved_member = *member;
2429 resolved_member.type = resolved_type_id;
2431 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2436 static int btf_ptr_check_member(struct btf_verifier_env *env,
2437 const struct btf_type *struct_type,
2438 const struct btf_member *member,
2439 const struct btf_type *member_type)
2441 u32 struct_size, struct_bits_off, bytes_offset;
2443 struct_size = struct_type->size;
2444 struct_bits_off = member->offset;
2445 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2447 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2448 btf_verifier_log_member(env, struct_type, member,
2449 "Member is not byte aligned");
2453 if (struct_size - bytes_offset < sizeof(void *)) {
2454 btf_verifier_log_member(env, struct_type, member,
2455 "Member exceeds struct_size");
2462 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2463 const struct btf_type *t,
2468 if (btf_type_vlen(t)) {
2469 btf_verifier_log_type(env, t, "vlen != 0");
2473 if (btf_type_kflag(t)) {
2474 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2478 if (!BTF_TYPE_ID_VALID(t->type)) {
2479 btf_verifier_log_type(env, t, "Invalid type_id");
2483 /* typedef/type_tag type must have a valid name, and other ref types,
2484 * volatile, const, restrict, should have a null name.
2486 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2488 !btf_name_valid_identifier(env->btf, t->name_off)) {
2489 btf_verifier_log_type(env, t, "Invalid name");
2492 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2493 value = btf_name_by_offset(env->btf, t->name_off);
2494 if (!value || !value[0]) {
2495 btf_verifier_log_type(env, t, "Invalid name");
2500 btf_verifier_log_type(env, t, "Invalid name");
2505 btf_verifier_log_type(env, t, NULL);
2510 static int btf_modifier_resolve(struct btf_verifier_env *env,
2511 const struct resolve_vertex *v)
2513 const struct btf_type *t = v->t;
2514 const struct btf_type *next_type;
2515 u32 next_type_id = t->type;
2516 struct btf *btf = env->btf;
2518 next_type = btf_type_by_id(btf, next_type_id);
2519 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2520 btf_verifier_log_type(env, v->t, "Invalid type_id");
2524 if (!env_type_is_resolve_sink(env, next_type) &&
2525 !env_type_is_resolved(env, next_type_id))
2526 return env_stack_push(env, next_type, next_type_id);
2528 /* Figure out the resolved next_type_id with size.
2529 * They will be stored in the current modifier's
2530 * resolved_ids and resolved_sizes such that it can
2531 * save us a few type-following when we use it later (e.g. in
2534 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2535 if (env_type_is_resolved(env, next_type_id))
2536 next_type = btf_type_id_resolve(btf, &next_type_id);
2538 /* "typedef void new_void", "const void"...etc */
2539 if (!btf_type_is_void(next_type) &&
2540 !btf_type_is_fwd(next_type) &&
2541 !btf_type_is_func_proto(next_type)) {
2542 btf_verifier_log_type(env, v->t, "Invalid type_id");
2547 env_stack_pop_resolved(env, next_type_id, 0);
2552 static int btf_var_resolve(struct btf_verifier_env *env,
2553 const struct resolve_vertex *v)
2555 const struct btf_type *next_type;
2556 const struct btf_type *t = v->t;
2557 u32 next_type_id = t->type;
2558 struct btf *btf = env->btf;
2560 next_type = btf_type_by_id(btf, next_type_id);
2561 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2562 btf_verifier_log_type(env, v->t, "Invalid type_id");
2566 if (!env_type_is_resolve_sink(env, next_type) &&
2567 !env_type_is_resolved(env, next_type_id))
2568 return env_stack_push(env, next_type, next_type_id);
2570 if (btf_type_is_modifier(next_type)) {
2571 const struct btf_type *resolved_type;
2572 u32 resolved_type_id;
2574 resolved_type_id = next_type_id;
2575 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2577 if (btf_type_is_ptr(resolved_type) &&
2578 !env_type_is_resolve_sink(env, resolved_type) &&
2579 !env_type_is_resolved(env, resolved_type_id))
2580 return env_stack_push(env, resolved_type,
2584 /* We must resolve to something concrete at this point, no
2585 * forward types or similar that would resolve to size of
2588 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2589 btf_verifier_log_type(env, v->t, "Invalid type_id");
2593 env_stack_pop_resolved(env, next_type_id, 0);
2598 static int btf_ptr_resolve(struct btf_verifier_env *env,
2599 const struct resolve_vertex *v)
2601 const struct btf_type *next_type;
2602 const struct btf_type *t = v->t;
2603 u32 next_type_id = t->type;
2604 struct btf *btf = env->btf;
2606 next_type = btf_type_by_id(btf, next_type_id);
2607 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2608 btf_verifier_log_type(env, v->t, "Invalid type_id");
2612 if (!env_type_is_resolve_sink(env, next_type) &&
2613 !env_type_is_resolved(env, next_type_id))
2614 return env_stack_push(env, next_type, next_type_id);
2616 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2617 * the modifier may have stopped resolving when it was resolved
2618 * to a ptr (last-resolved-ptr).
2620 * We now need to continue from the last-resolved-ptr to
2621 * ensure the last-resolved-ptr will not referring back to
2622 * the current ptr (t).
2624 if (btf_type_is_modifier(next_type)) {
2625 const struct btf_type *resolved_type;
2626 u32 resolved_type_id;
2628 resolved_type_id = next_type_id;
2629 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2631 if (btf_type_is_ptr(resolved_type) &&
2632 !env_type_is_resolve_sink(env, resolved_type) &&
2633 !env_type_is_resolved(env, resolved_type_id))
2634 return env_stack_push(env, resolved_type,
2638 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2639 if (env_type_is_resolved(env, next_type_id))
2640 next_type = btf_type_id_resolve(btf, &next_type_id);
2642 if (!btf_type_is_void(next_type) &&
2643 !btf_type_is_fwd(next_type) &&
2644 !btf_type_is_func_proto(next_type)) {
2645 btf_verifier_log_type(env, v->t, "Invalid type_id");
2650 env_stack_pop_resolved(env, next_type_id, 0);
2655 static void btf_modifier_show(const struct btf *btf,
2656 const struct btf_type *t,
2657 u32 type_id, void *data,
2658 u8 bits_offset, struct btf_show *show)
2660 if (btf->resolved_ids)
2661 t = btf_type_id_resolve(btf, &type_id);
2663 t = btf_type_skip_modifiers(btf, type_id, NULL);
2665 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2668 static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2669 u32 type_id, void *data, u8 bits_offset,
2670 struct btf_show *show)
2672 t = btf_type_id_resolve(btf, &type_id);
2674 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2677 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2678 u32 type_id, void *data, u8 bits_offset,
2679 struct btf_show *show)
2683 safe_data = btf_show_start_type(show, t, type_id, data);
2687 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2688 if (show->flags & BTF_SHOW_PTR_RAW)
2689 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2691 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2692 btf_show_end_type(show);
2695 static void btf_ref_type_log(struct btf_verifier_env *env,
2696 const struct btf_type *t)
2698 btf_verifier_log(env, "type_id=%u", t->type);
2701 static struct btf_kind_operations modifier_ops = {
2702 .check_meta = btf_ref_type_check_meta,
2703 .resolve = btf_modifier_resolve,
2704 .check_member = btf_modifier_check_member,
2705 .check_kflag_member = btf_modifier_check_kflag_member,
2706 .log_details = btf_ref_type_log,
2707 .show = btf_modifier_show,
2710 static struct btf_kind_operations ptr_ops = {
2711 .check_meta = btf_ref_type_check_meta,
2712 .resolve = btf_ptr_resolve,
2713 .check_member = btf_ptr_check_member,
2714 .check_kflag_member = btf_generic_check_kflag_member,
2715 .log_details = btf_ref_type_log,
2716 .show = btf_ptr_show,
2719 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2720 const struct btf_type *t,
2723 if (btf_type_vlen(t)) {
2724 btf_verifier_log_type(env, t, "vlen != 0");
2729 btf_verifier_log_type(env, t, "type != 0");
2733 /* fwd type must have a valid name */
2735 !btf_name_valid_identifier(env->btf, t->name_off)) {
2736 btf_verifier_log_type(env, t, "Invalid name");
2740 btf_verifier_log_type(env, t, NULL);
2745 static void btf_fwd_type_log(struct btf_verifier_env *env,
2746 const struct btf_type *t)
2748 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2751 static struct btf_kind_operations fwd_ops = {
2752 .check_meta = btf_fwd_check_meta,
2753 .resolve = btf_df_resolve,
2754 .check_member = btf_df_check_member,
2755 .check_kflag_member = btf_df_check_kflag_member,
2756 .log_details = btf_fwd_type_log,
2757 .show = btf_df_show,
2760 static int btf_array_check_member(struct btf_verifier_env *env,
2761 const struct btf_type *struct_type,
2762 const struct btf_member *member,
2763 const struct btf_type *member_type)
2765 u32 struct_bits_off = member->offset;
2766 u32 struct_size, bytes_offset;
2767 u32 array_type_id, array_size;
2768 struct btf *btf = env->btf;
2770 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2771 btf_verifier_log_member(env, struct_type, member,
2772 "Member is not byte aligned");
2776 array_type_id = member->type;
2777 btf_type_id_size(btf, &array_type_id, &array_size);
2778 struct_size = struct_type->size;
2779 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2780 if (struct_size - bytes_offset < array_size) {
2781 btf_verifier_log_member(env, struct_type, member,
2782 "Member exceeds struct_size");
2789 static s32 btf_array_check_meta(struct btf_verifier_env *env,
2790 const struct btf_type *t,
2793 const struct btf_array *array = btf_type_array(t);
2794 u32 meta_needed = sizeof(*array);
2796 if (meta_left < meta_needed) {
2797 btf_verifier_log_basic(env, t,
2798 "meta_left:%u meta_needed:%u",
2799 meta_left, meta_needed);
2803 /* array type should not have a name */
2805 btf_verifier_log_type(env, t, "Invalid name");
2809 if (btf_type_vlen(t)) {
2810 btf_verifier_log_type(env, t, "vlen != 0");
2814 if (btf_type_kflag(t)) {
2815 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2820 btf_verifier_log_type(env, t, "size != 0");
2824 /* Array elem type and index type cannot be in type void,
2825 * so !array->type and !array->index_type are not allowed.
2827 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2828 btf_verifier_log_type(env, t, "Invalid elem");
2832 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2833 btf_verifier_log_type(env, t, "Invalid index");
2837 btf_verifier_log_type(env, t, NULL);
2842 static int btf_array_resolve(struct btf_verifier_env *env,
2843 const struct resolve_vertex *v)
2845 const struct btf_array *array = btf_type_array(v->t);
2846 const struct btf_type *elem_type, *index_type;
2847 u32 elem_type_id, index_type_id;
2848 struct btf *btf = env->btf;
2851 /* Check array->index_type */
2852 index_type_id = array->index_type;
2853 index_type = btf_type_by_id(btf, index_type_id);
2854 if (btf_type_nosize_or_null(index_type) ||
2855 btf_type_is_resolve_source_only(index_type)) {
2856 btf_verifier_log_type(env, v->t, "Invalid index");
2860 if (!env_type_is_resolve_sink(env, index_type) &&
2861 !env_type_is_resolved(env, index_type_id))
2862 return env_stack_push(env, index_type, index_type_id);
2864 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2865 if (!index_type || !btf_type_is_int(index_type) ||
2866 !btf_type_int_is_regular(index_type)) {
2867 btf_verifier_log_type(env, v->t, "Invalid index");
2871 /* Check array->type */
2872 elem_type_id = array->type;
2873 elem_type = btf_type_by_id(btf, elem_type_id);
2874 if (btf_type_nosize_or_null(elem_type) ||
2875 btf_type_is_resolve_source_only(elem_type)) {
2876 btf_verifier_log_type(env, v->t,
2881 if (!env_type_is_resolve_sink(env, elem_type) &&
2882 !env_type_is_resolved(env, elem_type_id))
2883 return env_stack_push(env, elem_type, elem_type_id);
2885 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2887 btf_verifier_log_type(env, v->t, "Invalid elem");
2891 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2892 btf_verifier_log_type(env, v->t, "Invalid array of int");
2896 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2897 btf_verifier_log_type(env, v->t,
2898 "Array size overflows U32_MAX");
2902 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2907 static void btf_array_log(struct btf_verifier_env *env,
2908 const struct btf_type *t)
2910 const struct btf_array *array = btf_type_array(t);
2912 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2913 array->type, array->index_type, array->nelems);
2916 static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2917 u32 type_id, void *data, u8 bits_offset,
2918 struct btf_show *show)
2920 const struct btf_array *array = btf_type_array(t);
2921 const struct btf_kind_operations *elem_ops;
2922 const struct btf_type *elem_type;
2923 u32 i, elem_size = 0, elem_type_id;
2926 elem_type_id = array->type;
2927 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2928 if (elem_type && btf_type_has_size(elem_type))
2929 elem_size = elem_type->size;
2931 if (elem_type && btf_type_is_int(elem_type)) {
2932 u32 int_type = btf_type_int(elem_type);
2934 encoding = BTF_INT_ENCODING(int_type);
2937 * BTF_INT_CHAR encoding never seems to be set for
2938 * char arrays, so if size is 1 and element is
2939 * printable as a char, we'll do that.
2942 encoding = BTF_INT_CHAR;
2945 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2950 elem_ops = btf_type_ops(elem_type);
2952 for (i = 0; i < array->nelems; i++) {
2954 btf_show_start_array_member(show);
2956 elem_ops->show(btf, elem_type, elem_type_id, data,
2960 btf_show_end_array_member(show);
2962 if (show->state.array_terminated)
2966 btf_show_end_array_type(show);
2969 static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2970 u32 type_id, void *data, u8 bits_offset,
2971 struct btf_show *show)
2973 const struct btf_member *m = show->state.member;
2976 * First check if any members would be shown (are non-zero).
2977 * See comments above "struct btf_show" definition for more
2978 * details on how this works at a high-level.
2980 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2981 if (!show->state.depth_check) {
2982 show->state.depth_check = show->state.depth + 1;
2983 show->state.depth_to_show = 0;
2985 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2986 show->state.member = m;
2988 if (show->state.depth_check != show->state.depth + 1)
2990 show->state.depth_check = 0;
2992 if (show->state.depth_to_show <= show->state.depth)
2995 * Reaching here indicates we have recursed and found
2996 * non-zero array member(s).
2999 __btf_array_show(btf, t, type_id, data, bits_offset, show);
3002 static struct btf_kind_operations array_ops = {
3003 .check_meta = btf_array_check_meta,
3004 .resolve = btf_array_resolve,
3005 .check_member = btf_array_check_member,
3006 .check_kflag_member = btf_generic_check_kflag_member,
3007 .log_details = btf_array_log,
3008 .show = btf_array_show,
3011 static int btf_struct_check_member(struct btf_verifier_env *env,
3012 const struct btf_type *struct_type,
3013 const struct btf_member *member,
3014 const struct btf_type *member_type)
3016 u32 struct_bits_off = member->offset;
3017 u32 struct_size, bytes_offset;
3019 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3020 btf_verifier_log_member(env, struct_type, member,
3021 "Member is not byte aligned");
3025 struct_size = struct_type->size;
3026 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3027 if (struct_size - bytes_offset < member_type->size) {
3028 btf_verifier_log_member(env, struct_type, member,
3029 "Member exceeds struct_size");
3036 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3037 const struct btf_type *t,
3040 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3041 const struct btf_member *member;
3042 u32 meta_needed, last_offset;
3043 struct btf *btf = env->btf;
3044 u32 struct_size = t->size;
3048 meta_needed = btf_type_vlen(t) * sizeof(*member);
3049 if (meta_left < meta_needed) {
3050 btf_verifier_log_basic(env, t,
3051 "meta_left:%u meta_needed:%u",
3052 meta_left, meta_needed);
3056 /* struct type either no name or a valid one */
3058 !btf_name_valid_identifier(env->btf, t->name_off)) {
3059 btf_verifier_log_type(env, t, "Invalid name");
3063 btf_verifier_log_type(env, t, NULL);
3066 for_each_member(i, t, member) {
3067 if (!btf_name_offset_valid(btf, member->name_off)) {
3068 btf_verifier_log_member(env, t, member,
3069 "Invalid member name_offset:%u",
3074 /* struct member either no name or a valid one */
3075 if (member->name_off &&
3076 !btf_name_valid_identifier(btf, member->name_off)) {
3077 btf_verifier_log_member(env, t, member, "Invalid name");
3080 /* A member cannot be in type void */
3081 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3082 btf_verifier_log_member(env, t, member,
3087 offset = __btf_member_bit_offset(t, member);
3088 if (is_union && offset) {
3089 btf_verifier_log_member(env, t, member,
3090 "Invalid member bits_offset");
3095 * ">" instead of ">=" because the last member could be
3098 if (last_offset > offset) {
3099 btf_verifier_log_member(env, t, member,
3100 "Invalid member bits_offset");
3104 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3105 btf_verifier_log_member(env, t, member,
3106 "Member bits_offset exceeds its struct size");
3110 btf_verifier_log_member(env, t, member, NULL);
3111 last_offset = offset;
3117 static int btf_struct_resolve(struct btf_verifier_env *env,
3118 const struct resolve_vertex *v)
3120 const struct btf_member *member;
3124 /* Before continue resolving the next_member,
3125 * ensure the last member is indeed resolved to a
3126 * type with size info.
3128 if (v->next_member) {
3129 const struct btf_type *last_member_type;
3130 const struct btf_member *last_member;
3131 u32 last_member_type_id;
3133 last_member = btf_type_member(v->t) + v->next_member - 1;
3134 last_member_type_id = last_member->type;
3135 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3136 last_member_type_id)))
3139 last_member_type = btf_type_by_id(env->btf,
3140 last_member_type_id);
3141 if (btf_type_kflag(v->t))
3142 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3146 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3153 for_each_member_from(i, v->next_member, v->t, member) {
3154 u32 member_type_id = member->type;
3155 const struct btf_type *member_type = btf_type_by_id(env->btf,
3158 if (btf_type_nosize_or_null(member_type) ||
3159 btf_type_is_resolve_source_only(member_type)) {
3160 btf_verifier_log_member(env, v->t, member,
3165 if (!env_type_is_resolve_sink(env, member_type) &&
3166 !env_type_is_resolved(env, member_type_id)) {
3167 env_stack_set_next_member(env, i + 1);
3168 return env_stack_push(env, member_type, member_type_id);
3171 if (btf_type_kflag(v->t))
3172 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3176 err = btf_type_ops(member_type)->check_member(env, v->t,
3183 env_stack_pop_resolved(env, 0, 0);
3188 static void btf_struct_log(struct btf_verifier_env *env,
3189 const struct btf_type *t)
3191 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3194 enum btf_field_type {
3195 BTF_FIELD_SPIN_LOCK,
3201 BTF_FIELD_IGNORE = 0,
3202 BTF_FIELD_FOUND = 1,
3205 struct btf_field_info {
3208 enum bpf_kptr_type type;
3211 static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3212 u32 off, int sz, struct btf_field_info *info)
3214 if (!__btf_type_is_struct(t))
3215 return BTF_FIELD_IGNORE;
3217 return BTF_FIELD_IGNORE;
3219 return BTF_FIELD_FOUND;
3222 static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3223 u32 off, int sz, struct btf_field_info *info)
3225 enum bpf_kptr_type type;
3228 /* For PTR, sz is always == 8 */
3229 if (!btf_type_is_ptr(t))
3230 return BTF_FIELD_IGNORE;
3231 t = btf_type_by_id(btf, t->type);
3233 if (!btf_type_is_type_tag(t))
3234 return BTF_FIELD_IGNORE;
3235 /* Reject extra tags */
3236 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3238 if (!strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3239 type = BPF_KPTR_UNREF;
3240 else if (!strcmp("kptr_ref", __btf_name_by_offset(btf, t->name_off)))
3241 type = BPF_KPTR_REF;
3245 /* Get the base type */
3246 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3247 /* Only pointer to struct is allowed */
3248 if (!__btf_type_is_struct(t))
3251 info->type_id = res_id;
3254 return BTF_FIELD_FOUND;
3257 static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t,
3258 const char *name, int sz, int align,
3259 enum btf_field_type field_type,
3260 struct btf_field_info *info, int info_cnt)
3262 const struct btf_member *member;
3263 struct btf_field_info tmp;
3267 for_each_member(i, t, member) {
3268 const struct btf_type *member_type = btf_type_by_id(btf,
3271 if (name && strcmp(__btf_name_by_offset(btf, member_type->name_off), name))
3274 off = __btf_member_bit_offset(t, member);
3276 /* valid C code cannot generate such BTF */
3282 switch (field_type) {
3283 case BTF_FIELD_SPIN_LOCK:
3284 case BTF_FIELD_TIMER:
3285 ret = btf_find_struct(btf, member_type, off, sz,
3286 idx < info_cnt ? &info[idx] : &tmp);
3290 case BTF_FIELD_KPTR:
3291 ret = btf_find_kptr(btf, member_type, off, sz,
3292 idx < info_cnt ? &info[idx] : &tmp);
3300 if (ret == BTF_FIELD_IGNORE)
3302 if (idx >= info_cnt)
3309 static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3310 const char *name, int sz, int align,
3311 enum btf_field_type field_type,
3312 struct btf_field_info *info, int info_cnt)
3314 const struct btf_var_secinfo *vsi;
3315 struct btf_field_info tmp;
3319 for_each_vsi(i, t, vsi) {
3320 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3321 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3325 if (name && strcmp(__btf_name_by_offset(btf, var_type->name_off), name))
3327 if (vsi->size != sz)
3332 switch (field_type) {
3333 case BTF_FIELD_SPIN_LOCK:
3334 case BTF_FIELD_TIMER:
3335 ret = btf_find_struct(btf, var_type, off, sz,
3336 idx < info_cnt ? &info[idx] : &tmp);
3340 case BTF_FIELD_KPTR:
3341 ret = btf_find_kptr(btf, var_type, off, sz,
3342 idx < info_cnt ? &info[idx] : &tmp);
3350 if (ret == BTF_FIELD_IGNORE)
3352 if (idx >= info_cnt)
3359 static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3360 enum btf_field_type field_type,
3361 struct btf_field_info *info, int info_cnt)
3366 switch (field_type) {
3367 case BTF_FIELD_SPIN_LOCK:
3368 name = "bpf_spin_lock";
3369 sz = sizeof(struct bpf_spin_lock);
3370 align = __alignof__(struct bpf_spin_lock);
3372 case BTF_FIELD_TIMER:
3374 sz = sizeof(struct bpf_timer);
3375 align = __alignof__(struct bpf_timer);
3377 case BTF_FIELD_KPTR:
3386 if (__btf_type_is_struct(t))
3387 return btf_find_struct_field(btf, t, name, sz, align, field_type, info, info_cnt);
3388 else if (btf_type_is_datasec(t))
3389 return btf_find_datasec_var(btf, t, name, sz, align, field_type, info, info_cnt);
3393 /* find 'struct bpf_spin_lock' in map value.
3394 * return >= 0 offset if found
3395 * and < 0 in case of error
3397 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
3399 struct btf_field_info info;
3402 ret = btf_find_field(btf, t, BTF_FIELD_SPIN_LOCK, &info, 1);
3410 int btf_find_timer(const struct btf *btf, const struct btf_type *t)
3412 struct btf_field_info info;
3415 ret = btf_find_field(btf, t, BTF_FIELD_TIMER, &info, 1);
3423 struct bpf_map_value_off *btf_parse_kptrs(const struct btf *btf,
3424 const struct btf_type *t)
3426 struct btf_field_info info_arr[BPF_MAP_VALUE_OFF_MAX];
3427 struct bpf_map_value_off *tab;
3428 struct btf *kernel_btf = NULL;
3429 struct module *mod = NULL;
3432 ret = btf_find_field(btf, t, BTF_FIELD_KPTR, info_arr, ARRAY_SIZE(info_arr));
3434 return ERR_PTR(ret);
3439 tab = kzalloc(offsetof(struct bpf_map_value_off, off[nr_off]), GFP_KERNEL | __GFP_NOWARN);
3441 return ERR_PTR(-ENOMEM);
3443 for (i = 0; i < nr_off; i++) {
3444 const struct btf_type *t;
3447 /* Find type in map BTF, and use it to look up the matching type
3448 * in vmlinux or module BTFs, by name and kind.
3450 t = btf_type_by_id(btf, info_arr[i].type_id);
3451 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3458 /* Find and stash the function pointer for the destruction function that
3459 * needs to be eventually invoked from the map free path.
3461 if (info_arr[i].type == BPF_KPTR_REF) {
3462 const struct btf_type *dtor_func;
3463 const char *dtor_func_name;
3467 /* This call also serves as a whitelist of allowed objects that
3468 * can be used as a referenced pointer and be stored in a map at
3471 dtor_btf_id = btf_find_dtor_kfunc(kernel_btf, id);
3472 if (dtor_btf_id < 0) {
3477 dtor_func = btf_type_by_id(kernel_btf, dtor_btf_id);
3483 if (btf_is_module(kernel_btf)) {
3484 mod = btf_try_get_module(kernel_btf);
3491 /* We already verified dtor_func to be btf_type_is_func
3492 * in register_btf_id_dtor_kfuncs.
3494 dtor_func_name = __btf_name_by_offset(kernel_btf, dtor_func->name_off);
3495 addr = kallsyms_lookup_name(dtor_func_name);
3500 tab->off[i].kptr.dtor = (void *)addr;
3503 tab->off[i].offset = info_arr[i].off;
3504 tab->off[i].type = info_arr[i].type;
3505 tab->off[i].kptr.btf_id = id;
3506 tab->off[i].kptr.btf = kernel_btf;
3507 tab->off[i].kptr.module = mod;
3509 tab->nr_off = nr_off;
3514 btf_put(kernel_btf);
3517 btf_put(tab->off[i].kptr.btf);
3518 if (tab->off[i].kptr.module)
3519 module_put(tab->off[i].kptr.module);
3522 return ERR_PTR(ret);
3525 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3526 u32 type_id, void *data, u8 bits_offset,
3527 struct btf_show *show)
3529 const struct btf_member *member;
3533 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3537 for_each_member(i, t, member) {
3538 const struct btf_type *member_type = btf_type_by_id(btf,
3540 const struct btf_kind_operations *ops;
3541 u32 member_offset, bitfield_size;
3545 btf_show_start_member(show, member);
3547 member_offset = __btf_member_bit_offset(t, member);
3548 bitfield_size = __btf_member_bitfield_size(t, member);
3549 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3550 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3551 if (bitfield_size) {
3552 safe_data = btf_show_start_type(show, member_type,
3554 data + bytes_offset);
3556 btf_bitfield_show(safe_data,
3558 bitfield_size, show);
3559 btf_show_end_type(show);
3561 ops = btf_type_ops(member_type);
3562 ops->show(btf, member_type, member->type,
3563 data + bytes_offset, bits8_offset, show);
3566 btf_show_end_member(show);
3569 btf_show_end_struct_type(show);
3572 static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3573 u32 type_id, void *data, u8 bits_offset,
3574 struct btf_show *show)
3576 const struct btf_member *m = show->state.member;
3579 * First check if any members would be shown (are non-zero).
3580 * See comments above "struct btf_show" definition for more
3581 * details on how this works at a high-level.
3583 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3584 if (!show->state.depth_check) {
3585 show->state.depth_check = show->state.depth + 1;
3586 show->state.depth_to_show = 0;
3588 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3589 /* Restore saved member data here */
3590 show->state.member = m;
3591 if (show->state.depth_check != show->state.depth + 1)
3593 show->state.depth_check = 0;
3595 if (show->state.depth_to_show <= show->state.depth)
3598 * Reaching here indicates we have recursed and found
3599 * non-zero child values.
3603 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3606 static struct btf_kind_operations struct_ops = {
3607 .check_meta = btf_struct_check_meta,
3608 .resolve = btf_struct_resolve,
3609 .check_member = btf_struct_check_member,
3610 .check_kflag_member = btf_generic_check_kflag_member,
3611 .log_details = btf_struct_log,
3612 .show = btf_struct_show,
3615 static int btf_enum_check_member(struct btf_verifier_env *env,
3616 const struct btf_type *struct_type,
3617 const struct btf_member *member,
3618 const struct btf_type *member_type)
3620 u32 struct_bits_off = member->offset;
3621 u32 struct_size, bytes_offset;
3623 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3624 btf_verifier_log_member(env, struct_type, member,
3625 "Member is not byte aligned");
3629 struct_size = struct_type->size;
3630 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3631 if (struct_size - bytes_offset < member_type->size) {
3632 btf_verifier_log_member(env, struct_type, member,
3633 "Member exceeds struct_size");
3640 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3641 const struct btf_type *struct_type,
3642 const struct btf_member *member,
3643 const struct btf_type *member_type)
3645 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3646 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3648 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3649 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3651 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3652 btf_verifier_log_member(env, struct_type, member,
3653 "Member is not byte aligned");
3657 nr_bits = int_bitsize;
3658 } else if (nr_bits > int_bitsize) {
3659 btf_verifier_log_member(env, struct_type, member,
3660 "Invalid member bitfield_size");
3664 struct_size = struct_type->size;
3665 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3666 if (struct_size < bytes_end) {
3667 btf_verifier_log_member(env, struct_type, member,
3668 "Member exceeds struct_size");
3675 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3676 const struct btf_type *t,
3679 const struct btf_enum *enums = btf_type_enum(t);
3680 struct btf *btf = env->btf;
3681 const char *fmt_str;
3685 nr_enums = btf_type_vlen(t);
3686 meta_needed = nr_enums * sizeof(*enums);
3688 if (meta_left < meta_needed) {
3689 btf_verifier_log_basic(env, t,
3690 "meta_left:%u meta_needed:%u",
3691 meta_left, meta_needed);
3695 if (t->size > 8 || !is_power_of_2(t->size)) {
3696 btf_verifier_log_type(env, t, "Unexpected size");
3700 /* enum type either no name or a valid one */
3702 !btf_name_valid_identifier(env->btf, t->name_off)) {
3703 btf_verifier_log_type(env, t, "Invalid name");
3707 btf_verifier_log_type(env, t, NULL);
3709 for (i = 0; i < nr_enums; i++) {
3710 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3711 btf_verifier_log(env, "\tInvalid name_offset:%u",
3716 /* enum member must have a valid name */
3717 if (!enums[i].name_off ||
3718 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3719 btf_verifier_log_type(env, t, "Invalid name");
3723 if (env->log.level == BPF_LOG_KERNEL)
3725 fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n";
3726 btf_verifier_log(env, fmt_str,
3727 __btf_name_by_offset(btf, enums[i].name_off),
3734 static void btf_enum_log(struct btf_verifier_env *env,
3735 const struct btf_type *t)
3737 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3740 static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
3741 u32 type_id, void *data, u8 bits_offset,
3742 struct btf_show *show)
3744 const struct btf_enum *enums = btf_type_enum(t);
3745 u32 i, nr_enums = btf_type_vlen(t);
3749 safe_data = btf_show_start_type(show, t, type_id, data);
3753 v = *(int *)safe_data;
3755 for (i = 0; i < nr_enums; i++) {
3756 if (v != enums[i].val)
3759 btf_show_type_value(show, "%s",
3760 __btf_name_by_offset(btf,
3761 enums[i].name_off));
3763 btf_show_end_type(show);
3767 if (btf_type_kflag(t))
3768 btf_show_type_value(show, "%d", v);
3770 btf_show_type_value(show, "%u", v);
3771 btf_show_end_type(show);
3774 static struct btf_kind_operations enum_ops = {
3775 .check_meta = btf_enum_check_meta,
3776 .resolve = btf_df_resolve,
3777 .check_member = btf_enum_check_member,
3778 .check_kflag_member = btf_enum_check_kflag_member,
3779 .log_details = btf_enum_log,
3780 .show = btf_enum_show,
3783 static s32 btf_enum64_check_meta(struct btf_verifier_env *env,
3784 const struct btf_type *t,
3787 const struct btf_enum64 *enums = btf_type_enum64(t);
3788 struct btf *btf = env->btf;
3789 const char *fmt_str;
3793 nr_enums = btf_type_vlen(t);
3794 meta_needed = nr_enums * sizeof(*enums);
3796 if (meta_left < meta_needed) {
3797 btf_verifier_log_basic(env, t,
3798 "meta_left:%u meta_needed:%u",
3799 meta_left, meta_needed);
3803 if (t->size > 8 || !is_power_of_2(t->size)) {
3804 btf_verifier_log_type(env, t, "Unexpected size");
3808 /* enum type either no name or a valid one */
3810 !btf_name_valid_identifier(env->btf, t->name_off)) {
3811 btf_verifier_log_type(env, t, "Invalid name");
3815 btf_verifier_log_type(env, t, NULL);
3817 for (i = 0; i < nr_enums; i++) {
3818 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3819 btf_verifier_log(env, "\tInvalid name_offset:%u",
3824 /* enum member must have a valid name */
3825 if (!enums[i].name_off ||
3826 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3827 btf_verifier_log_type(env, t, "Invalid name");
3831 if (env->log.level == BPF_LOG_KERNEL)
3834 fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n";
3835 btf_verifier_log(env, fmt_str,
3836 __btf_name_by_offset(btf, enums[i].name_off),
3837 btf_enum64_value(enums + i));
3843 static void btf_enum64_show(const struct btf *btf, const struct btf_type *t,
3844 u32 type_id, void *data, u8 bits_offset,
3845 struct btf_show *show)
3847 const struct btf_enum64 *enums = btf_type_enum64(t);
3848 u32 i, nr_enums = btf_type_vlen(t);
3852 safe_data = btf_show_start_type(show, t, type_id, data);
3856 v = *(u64 *)safe_data;
3858 for (i = 0; i < nr_enums; i++) {
3859 if (v != btf_enum64_value(enums + i))
3862 btf_show_type_value(show, "%s",
3863 __btf_name_by_offset(btf,
3864 enums[i].name_off));
3866 btf_show_end_type(show);
3870 if (btf_type_kflag(t))
3871 btf_show_type_value(show, "%lld", v);
3873 btf_show_type_value(show, "%llu", v);
3874 btf_show_end_type(show);
3877 static struct btf_kind_operations enum64_ops = {
3878 .check_meta = btf_enum64_check_meta,
3879 .resolve = btf_df_resolve,
3880 .check_member = btf_enum_check_member,
3881 .check_kflag_member = btf_enum_check_kflag_member,
3882 .log_details = btf_enum_log,
3883 .show = btf_enum64_show,
3886 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
3887 const struct btf_type *t,
3890 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
3892 if (meta_left < meta_needed) {
3893 btf_verifier_log_basic(env, t,
3894 "meta_left:%u meta_needed:%u",
3895 meta_left, meta_needed);
3900 btf_verifier_log_type(env, t, "Invalid name");
3904 if (btf_type_kflag(t)) {
3905 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3909 btf_verifier_log_type(env, t, NULL);
3914 static void btf_func_proto_log(struct btf_verifier_env *env,
3915 const struct btf_type *t)
3917 const struct btf_param *args = (const struct btf_param *)(t + 1);
3918 u16 nr_args = btf_type_vlen(t), i;
3920 btf_verifier_log(env, "return=%u args=(", t->type);
3922 btf_verifier_log(env, "void");
3926 if (nr_args == 1 && !args[0].type) {
3927 /* Only one vararg */
3928 btf_verifier_log(env, "vararg");
3932 btf_verifier_log(env, "%u %s", args[0].type,
3933 __btf_name_by_offset(env->btf,
3935 for (i = 1; i < nr_args - 1; i++)
3936 btf_verifier_log(env, ", %u %s", args[i].type,
3937 __btf_name_by_offset(env->btf,
3941 const struct btf_param *last_arg = &args[nr_args - 1];
3944 btf_verifier_log(env, ", %u %s", last_arg->type,
3945 __btf_name_by_offset(env->btf,
3946 last_arg->name_off));
3948 btf_verifier_log(env, ", vararg");
3952 btf_verifier_log(env, ")");
3955 static struct btf_kind_operations func_proto_ops = {
3956 .check_meta = btf_func_proto_check_meta,
3957 .resolve = btf_df_resolve,
3959 * BTF_KIND_FUNC_PROTO cannot be directly referred by
3960 * a struct's member.
3962 * It should be a function pointer instead.
3963 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
3965 * Hence, there is no btf_func_check_member().
3967 .check_member = btf_df_check_member,
3968 .check_kflag_member = btf_df_check_kflag_member,
3969 .log_details = btf_func_proto_log,
3970 .show = btf_df_show,
3973 static s32 btf_func_check_meta(struct btf_verifier_env *env,
3974 const struct btf_type *t,
3978 !btf_name_valid_identifier(env->btf, t->name_off)) {
3979 btf_verifier_log_type(env, t, "Invalid name");
3983 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
3984 btf_verifier_log_type(env, t, "Invalid func linkage");
3988 if (btf_type_kflag(t)) {
3989 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3993 btf_verifier_log_type(env, t, NULL);
3998 static int btf_func_resolve(struct btf_verifier_env *env,
3999 const struct resolve_vertex *v)
4001 const struct btf_type *t = v->t;
4002 u32 next_type_id = t->type;
4005 err = btf_func_check(env, t);
4009 env_stack_pop_resolved(env, next_type_id, 0);
4013 static struct btf_kind_operations func_ops = {
4014 .check_meta = btf_func_check_meta,
4015 .resolve = btf_func_resolve,
4016 .check_member = btf_df_check_member,
4017 .check_kflag_member = btf_df_check_kflag_member,
4018 .log_details = btf_ref_type_log,
4019 .show = btf_df_show,
4022 static s32 btf_var_check_meta(struct btf_verifier_env *env,
4023 const struct btf_type *t,
4026 const struct btf_var *var;
4027 u32 meta_needed = sizeof(*var);
4029 if (meta_left < meta_needed) {
4030 btf_verifier_log_basic(env, t,
4031 "meta_left:%u meta_needed:%u",
4032 meta_left, meta_needed);
4036 if (btf_type_vlen(t)) {
4037 btf_verifier_log_type(env, t, "vlen != 0");
4041 if (btf_type_kflag(t)) {
4042 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4047 !__btf_name_valid(env->btf, t->name_off, true)) {
4048 btf_verifier_log_type(env, t, "Invalid name");
4052 /* A var cannot be in type void */
4053 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
4054 btf_verifier_log_type(env, t, "Invalid type_id");
4058 var = btf_type_var(t);
4059 if (var->linkage != BTF_VAR_STATIC &&
4060 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
4061 btf_verifier_log_type(env, t, "Linkage not supported");
4065 btf_verifier_log_type(env, t, NULL);
4070 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
4072 const struct btf_var *var = btf_type_var(t);
4074 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
4077 static const struct btf_kind_operations var_ops = {
4078 .check_meta = btf_var_check_meta,
4079 .resolve = btf_var_resolve,
4080 .check_member = btf_df_check_member,
4081 .check_kflag_member = btf_df_check_kflag_member,
4082 .log_details = btf_var_log,
4083 .show = btf_var_show,
4086 static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
4087 const struct btf_type *t,
4090 const struct btf_var_secinfo *vsi;
4091 u64 last_vsi_end_off = 0, sum = 0;
4094 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
4095 if (meta_left < meta_needed) {
4096 btf_verifier_log_basic(env, t,
4097 "meta_left:%u meta_needed:%u",
4098 meta_left, meta_needed);
4103 btf_verifier_log_type(env, t, "size == 0");
4107 if (btf_type_kflag(t)) {
4108 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4113 !btf_name_valid_section(env->btf, t->name_off)) {
4114 btf_verifier_log_type(env, t, "Invalid name");
4118 btf_verifier_log_type(env, t, NULL);
4120 for_each_vsi(i, t, vsi) {
4121 /* A var cannot be in type void */
4122 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
4123 btf_verifier_log_vsi(env, t, vsi,
4128 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
4129 btf_verifier_log_vsi(env, t, vsi,
4134 if (!vsi->size || vsi->size > t->size) {
4135 btf_verifier_log_vsi(env, t, vsi,
4140 last_vsi_end_off = vsi->offset + vsi->size;
4141 if (last_vsi_end_off > t->size) {
4142 btf_verifier_log_vsi(env, t, vsi,
4143 "Invalid offset+size");
4147 btf_verifier_log_vsi(env, t, vsi, NULL);
4151 if (t->size < sum) {
4152 btf_verifier_log_type(env, t, "Invalid btf_info size");
4159 static int btf_datasec_resolve(struct btf_verifier_env *env,
4160 const struct resolve_vertex *v)
4162 const struct btf_var_secinfo *vsi;
4163 struct btf *btf = env->btf;
4166 env->resolve_mode = RESOLVE_TBD;
4167 for_each_vsi_from(i, v->next_member, v->t, vsi) {
4168 u32 var_type_id = vsi->type, type_id, type_size = 0;
4169 const struct btf_type *var_type = btf_type_by_id(env->btf,
4171 if (!var_type || !btf_type_is_var(var_type)) {
4172 btf_verifier_log_vsi(env, v->t, vsi,
4173 "Not a VAR kind member");
4177 if (!env_type_is_resolve_sink(env, var_type) &&
4178 !env_type_is_resolved(env, var_type_id)) {
4179 env_stack_set_next_member(env, i + 1);
4180 return env_stack_push(env, var_type, var_type_id);
4183 type_id = var_type->type;
4184 if (!btf_type_id_size(btf, &type_id, &type_size)) {
4185 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
4189 if (vsi->size < type_size) {
4190 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4195 env_stack_pop_resolved(env, 0, 0);
4199 static void btf_datasec_log(struct btf_verifier_env *env,
4200 const struct btf_type *t)
4202 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4205 static void btf_datasec_show(const struct btf *btf,
4206 const struct btf_type *t, u32 type_id,
4207 void *data, u8 bits_offset,
4208 struct btf_show *show)
4210 const struct btf_var_secinfo *vsi;
4211 const struct btf_type *var;
4214 if (!btf_show_start_type(show, t, type_id, data))
4217 btf_show_type_value(show, "section (\"%s\") = {",
4218 __btf_name_by_offset(btf, t->name_off));
4219 for_each_vsi(i, t, vsi) {
4220 var = btf_type_by_id(btf, vsi->type);
4222 btf_show(show, ",");
4223 btf_type_ops(var)->show(btf, var, vsi->type,
4224 data + vsi->offset, bits_offset, show);
4226 btf_show_end_type(show);
4229 static const struct btf_kind_operations datasec_ops = {
4230 .check_meta = btf_datasec_check_meta,
4231 .resolve = btf_datasec_resolve,
4232 .check_member = btf_df_check_member,
4233 .check_kflag_member = btf_df_check_kflag_member,
4234 .log_details = btf_datasec_log,
4235 .show = btf_datasec_show,
4238 static s32 btf_float_check_meta(struct btf_verifier_env *env,
4239 const struct btf_type *t,
4242 if (btf_type_vlen(t)) {
4243 btf_verifier_log_type(env, t, "vlen != 0");
4247 if (btf_type_kflag(t)) {
4248 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4252 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4254 btf_verifier_log_type(env, t, "Invalid type_size");
4258 btf_verifier_log_type(env, t, NULL);
4263 static int btf_float_check_member(struct btf_verifier_env *env,
4264 const struct btf_type *struct_type,
4265 const struct btf_member *member,
4266 const struct btf_type *member_type)
4268 u64 start_offset_bytes;
4269 u64 end_offset_bytes;
4274 /* Different architectures have different alignment requirements, so
4275 * here we check only for the reasonable minimum. This way we ensure
4276 * that types after CO-RE can pass the kernel BTF verifier.
4278 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4279 align_bits = align_bytes * BITS_PER_BYTE;
4280 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4281 if (misalign_bits) {
4282 btf_verifier_log_member(env, struct_type, member,
4283 "Member is not properly aligned");
4287 start_offset_bytes = member->offset / BITS_PER_BYTE;
4288 end_offset_bytes = start_offset_bytes + member_type->size;
4289 if (end_offset_bytes > struct_type->size) {
4290 btf_verifier_log_member(env, struct_type, member,
4291 "Member exceeds struct_size");
4298 static void btf_float_log(struct btf_verifier_env *env,
4299 const struct btf_type *t)
4301 btf_verifier_log(env, "size=%u", t->size);
4304 static const struct btf_kind_operations float_ops = {
4305 .check_meta = btf_float_check_meta,
4306 .resolve = btf_df_resolve,
4307 .check_member = btf_float_check_member,
4308 .check_kflag_member = btf_generic_check_kflag_member,
4309 .log_details = btf_float_log,
4310 .show = btf_df_show,
4313 static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4314 const struct btf_type *t,
4317 const struct btf_decl_tag *tag;
4318 u32 meta_needed = sizeof(*tag);
4322 if (meta_left < meta_needed) {
4323 btf_verifier_log_basic(env, t,
4324 "meta_left:%u meta_needed:%u",
4325 meta_left, meta_needed);
4329 value = btf_name_by_offset(env->btf, t->name_off);
4330 if (!value || !value[0]) {
4331 btf_verifier_log_type(env, t, "Invalid value");
4335 if (btf_type_vlen(t)) {
4336 btf_verifier_log_type(env, t, "vlen != 0");
4340 if (btf_type_kflag(t)) {
4341 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4345 component_idx = btf_type_decl_tag(t)->component_idx;
4346 if (component_idx < -1) {
4347 btf_verifier_log_type(env, t, "Invalid component_idx");
4351 btf_verifier_log_type(env, t, NULL);
4356 static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4357 const struct resolve_vertex *v)
4359 const struct btf_type *next_type;
4360 const struct btf_type *t = v->t;
4361 u32 next_type_id = t->type;
4362 struct btf *btf = env->btf;
4366 next_type = btf_type_by_id(btf, next_type_id);
4367 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4368 btf_verifier_log_type(env, v->t, "Invalid type_id");
4372 if (!env_type_is_resolve_sink(env, next_type) &&
4373 !env_type_is_resolved(env, next_type_id))
4374 return env_stack_push(env, next_type, next_type_id);
4376 component_idx = btf_type_decl_tag(t)->component_idx;
4377 if (component_idx != -1) {
4378 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4379 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4383 if (btf_type_is_struct(next_type)) {
4384 vlen = btf_type_vlen(next_type);
4386 /* next_type should be a function */
4387 next_type = btf_type_by_id(btf, next_type->type);
4388 vlen = btf_type_vlen(next_type);
4391 if ((u32)component_idx >= vlen) {
4392 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4397 env_stack_pop_resolved(env, next_type_id, 0);
4402 static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4404 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4405 btf_type_decl_tag(t)->component_idx);
4408 static const struct btf_kind_operations decl_tag_ops = {
4409 .check_meta = btf_decl_tag_check_meta,
4410 .resolve = btf_decl_tag_resolve,
4411 .check_member = btf_df_check_member,
4412 .check_kflag_member = btf_df_check_kflag_member,
4413 .log_details = btf_decl_tag_log,
4414 .show = btf_df_show,
4417 static int btf_func_proto_check(struct btf_verifier_env *env,
4418 const struct btf_type *t)
4420 const struct btf_type *ret_type;
4421 const struct btf_param *args;
4422 const struct btf *btf;
4427 args = (const struct btf_param *)(t + 1);
4428 nr_args = btf_type_vlen(t);
4430 /* Check func return type which could be "void" (t->type == 0) */
4432 u32 ret_type_id = t->type;
4434 ret_type = btf_type_by_id(btf, ret_type_id);
4436 btf_verifier_log_type(env, t, "Invalid return type");
4440 if (btf_type_is_resolve_source_only(ret_type)) {
4441 btf_verifier_log_type(env, t, "Invalid return type");
4445 if (btf_type_needs_resolve(ret_type) &&
4446 !env_type_is_resolved(env, ret_type_id)) {
4447 err = btf_resolve(env, ret_type, ret_type_id);
4452 /* Ensure the return type is a type that has a size */
4453 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4454 btf_verifier_log_type(env, t, "Invalid return type");
4462 /* Last func arg type_id could be 0 if it is a vararg */
4463 if (!args[nr_args - 1].type) {
4464 if (args[nr_args - 1].name_off) {
4465 btf_verifier_log_type(env, t, "Invalid arg#%u",
4473 for (i = 0; i < nr_args; i++) {
4474 const struct btf_type *arg_type;
4477 arg_type_id = args[i].type;
4478 arg_type = btf_type_by_id(btf, arg_type_id);
4480 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4485 if (btf_type_is_resolve_source_only(arg_type)) {
4486 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4490 if (args[i].name_off &&
4491 (!btf_name_offset_valid(btf, args[i].name_off) ||
4492 !btf_name_valid_identifier(btf, args[i].name_off))) {
4493 btf_verifier_log_type(env, t,
4494 "Invalid arg#%u", i + 1);
4499 if (btf_type_needs_resolve(arg_type) &&
4500 !env_type_is_resolved(env, arg_type_id)) {
4501 err = btf_resolve(env, arg_type, arg_type_id);
4506 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4507 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4516 static int btf_func_check(struct btf_verifier_env *env,
4517 const struct btf_type *t)
4519 const struct btf_type *proto_type;
4520 const struct btf_param *args;
4521 const struct btf *btf;
4525 proto_type = btf_type_by_id(btf, t->type);
4527 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4528 btf_verifier_log_type(env, t, "Invalid type_id");
4532 args = (const struct btf_param *)(proto_type + 1);
4533 nr_args = btf_type_vlen(proto_type);
4534 for (i = 0; i < nr_args; i++) {
4535 if (!args[i].name_off && args[i].type) {
4536 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4544 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4545 [BTF_KIND_INT] = &int_ops,
4546 [BTF_KIND_PTR] = &ptr_ops,
4547 [BTF_KIND_ARRAY] = &array_ops,
4548 [BTF_KIND_STRUCT] = &struct_ops,
4549 [BTF_KIND_UNION] = &struct_ops,
4550 [BTF_KIND_ENUM] = &enum_ops,
4551 [BTF_KIND_FWD] = &fwd_ops,
4552 [BTF_KIND_TYPEDEF] = &modifier_ops,
4553 [BTF_KIND_VOLATILE] = &modifier_ops,
4554 [BTF_KIND_CONST] = &modifier_ops,
4555 [BTF_KIND_RESTRICT] = &modifier_ops,
4556 [BTF_KIND_FUNC] = &func_ops,
4557 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4558 [BTF_KIND_VAR] = &var_ops,
4559 [BTF_KIND_DATASEC] = &datasec_ops,
4560 [BTF_KIND_FLOAT] = &float_ops,
4561 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4562 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4563 [BTF_KIND_ENUM64] = &enum64_ops,
4566 static s32 btf_check_meta(struct btf_verifier_env *env,
4567 const struct btf_type *t,
4570 u32 saved_meta_left = meta_left;
4573 if (meta_left < sizeof(*t)) {
4574 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4575 env->log_type_id, meta_left, sizeof(*t));
4578 meta_left -= sizeof(*t);
4580 if (t->info & ~BTF_INFO_MASK) {
4581 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4582 env->log_type_id, t->info);
4586 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4587 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4588 btf_verifier_log(env, "[%u] Invalid kind:%u",
4589 env->log_type_id, BTF_INFO_KIND(t->info));
4593 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4594 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4595 env->log_type_id, t->name_off);
4599 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4600 if (var_meta_size < 0)
4601 return var_meta_size;
4603 meta_left -= var_meta_size;
4605 return saved_meta_left - meta_left;
4608 static int btf_check_all_metas(struct btf_verifier_env *env)
4610 struct btf *btf = env->btf;
4611 struct btf_header *hdr;
4615 cur = btf->nohdr_data + hdr->type_off;
4616 end = cur + hdr->type_len;
4618 env->log_type_id = btf->base_btf ? btf->start_id : 1;
4620 struct btf_type *t = cur;
4623 meta_size = btf_check_meta(env, t, end - cur);
4627 btf_add_type(env, t);
4635 static bool btf_resolve_valid(struct btf_verifier_env *env,
4636 const struct btf_type *t,
4639 struct btf *btf = env->btf;
4641 if (!env_type_is_resolved(env, type_id))
4644 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
4645 return !btf_resolved_type_id(btf, type_id) &&
4646 !btf_resolved_type_size(btf, type_id);
4648 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
4649 return btf_resolved_type_id(btf, type_id) &&
4650 !btf_resolved_type_size(btf, type_id);
4652 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
4653 btf_type_is_var(t)) {
4654 t = btf_type_id_resolve(btf, &type_id);
4656 !btf_type_is_modifier(t) &&
4657 !btf_type_is_var(t) &&
4658 !btf_type_is_datasec(t);
4661 if (btf_type_is_array(t)) {
4662 const struct btf_array *array = btf_type_array(t);
4663 const struct btf_type *elem_type;
4664 u32 elem_type_id = array->type;
4667 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
4668 return elem_type && !btf_type_is_modifier(elem_type) &&
4669 (array->nelems * elem_size ==
4670 btf_resolved_type_size(btf, type_id));
4676 static int btf_resolve(struct btf_verifier_env *env,
4677 const struct btf_type *t, u32 type_id)
4679 u32 save_log_type_id = env->log_type_id;
4680 const struct resolve_vertex *v;
4683 env->resolve_mode = RESOLVE_TBD;
4684 env_stack_push(env, t, type_id);
4685 while (!err && (v = env_stack_peak(env))) {
4686 env->log_type_id = v->type_id;
4687 err = btf_type_ops(v->t)->resolve(env, v);
4690 env->log_type_id = type_id;
4691 if (err == -E2BIG) {
4692 btf_verifier_log_type(env, t,
4693 "Exceeded max resolving depth:%u",
4695 } else if (err == -EEXIST) {
4696 btf_verifier_log_type(env, t, "Loop detected");
4699 /* Final sanity check */
4700 if (!err && !btf_resolve_valid(env, t, type_id)) {
4701 btf_verifier_log_type(env, t, "Invalid resolve state");
4705 env->log_type_id = save_log_type_id;
4709 static int btf_check_all_types(struct btf_verifier_env *env)
4711 struct btf *btf = env->btf;
4712 const struct btf_type *t;
4716 err = env_resolve_init(env);
4721 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
4722 type_id = btf->start_id + i;
4723 t = btf_type_by_id(btf, type_id);
4725 env->log_type_id = type_id;
4726 if (btf_type_needs_resolve(t) &&
4727 !env_type_is_resolved(env, type_id)) {
4728 err = btf_resolve(env, t, type_id);
4733 if (btf_type_is_func_proto(t)) {
4734 err = btf_func_proto_check(env, t);
4743 static int btf_parse_type_sec(struct btf_verifier_env *env)
4745 const struct btf_header *hdr = &env->btf->hdr;
4748 /* Type section must align to 4 bytes */
4749 if (hdr->type_off & (sizeof(u32) - 1)) {
4750 btf_verifier_log(env, "Unaligned type_off");
4754 if (!env->btf->base_btf && !hdr->type_len) {
4755 btf_verifier_log(env, "No type found");
4759 err = btf_check_all_metas(env);
4763 return btf_check_all_types(env);
4766 static int btf_parse_str_sec(struct btf_verifier_env *env)
4768 const struct btf_header *hdr;
4769 struct btf *btf = env->btf;
4770 const char *start, *end;
4773 start = btf->nohdr_data + hdr->str_off;
4774 end = start + hdr->str_len;
4776 if (end != btf->data + btf->data_size) {
4777 btf_verifier_log(env, "String section is not at the end");
4781 btf->strings = start;
4783 if (btf->base_btf && !hdr->str_len)
4785 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
4786 btf_verifier_log(env, "Invalid string section");
4789 if (!btf->base_btf && start[0]) {
4790 btf_verifier_log(env, "Invalid string section");
4797 static const size_t btf_sec_info_offset[] = {
4798 offsetof(struct btf_header, type_off),
4799 offsetof(struct btf_header, str_off),
4802 static int btf_sec_info_cmp(const void *a, const void *b)
4804 const struct btf_sec_info *x = a;
4805 const struct btf_sec_info *y = b;
4807 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
4810 static int btf_check_sec_info(struct btf_verifier_env *env,
4813 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
4814 u32 total, expected_total, i;
4815 const struct btf_header *hdr;
4816 const struct btf *btf;
4821 /* Populate the secs from hdr */
4822 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
4823 secs[i] = *(struct btf_sec_info *)((void *)hdr +
4824 btf_sec_info_offset[i]);
4826 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
4827 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
4829 /* Check for gaps and overlap among sections */
4831 expected_total = btf_data_size - hdr->hdr_len;
4832 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
4833 if (expected_total < secs[i].off) {
4834 btf_verifier_log(env, "Invalid section offset");
4837 if (total < secs[i].off) {
4839 btf_verifier_log(env, "Unsupported section found");
4842 if (total > secs[i].off) {
4843 btf_verifier_log(env, "Section overlap found");
4846 if (expected_total - total < secs[i].len) {
4847 btf_verifier_log(env,
4848 "Total section length too long");
4851 total += secs[i].len;
4854 /* There is data other than hdr and known sections */
4855 if (expected_total != total) {
4856 btf_verifier_log(env, "Unsupported section found");
4863 static int btf_parse_hdr(struct btf_verifier_env *env)
4865 u32 hdr_len, hdr_copy, btf_data_size;
4866 const struct btf_header *hdr;
4870 btf_data_size = btf->data_size;
4872 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
4873 btf_verifier_log(env, "hdr_len not found");
4878 hdr_len = hdr->hdr_len;
4879 if (btf_data_size < hdr_len) {
4880 btf_verifier_log(env, "btf_header not found");
4884 /* Ensure the unsupported header fields are zero */
4885 if (hdr_len > sizeof(btf->hdr)) {
4886 u8 *expected_zero = btf->data + sizeof(btf->hdr);
4887 u8 *end = btf->data + hdr_len;
4889 for (; expected_zero < end; expected_zero++) {
4890 if (*expected_zero) {
4891 btf_verifier_log(env, "Unsupported btf_header");
4897 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
4898 memcpy(&btf->hdr, btf->data, hdr_copy);
4902 btf_verifier_log_hdr(env, btf_data_size);
4904 if (hdr->magic != BTF_MAGIC) {
4905 btf_verifier_log(env, "Invalid magic");
4909 if (hdr->version != BTF_VERSION) {
4910 btf_verifier_log(env, "Unsupported version");
4915 btf_verifier_log(env, "Unsupported flags");
4919 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
4920 btf_verifier_log(env, "No data");
4924 return btf_check_sec_info(env, btf_data_size);
4927 static int btf_check_type_tags(struct btf_verifier_env *env,
4928 struct btf *btf, int start_id)
4930 int i, n, good_id = start_id - 1;
4933 n = btf_nr_types(btf);
4934 for (i = start_id; i < n; i++) {
4935 const struct btf_type *t;
4936 int chain_limit = 32;
4939 t = btf_type_by_id(btf, i);
4942 if (!btf_type_is_modifier(t))
4947 in_tags = btf_type_is_type_tag(t);
4948 while (btf_type_is_modifier(t)) {
4949 if (!chain_limit--) {
4950 btf_verifier_log(env, "Max chain length or cycle detected");
4953 if (btf_type_is_type_tag(t)) {
4955 btf_verifier_log(env, "Type tags don't precede modifiers");
4958 } else if (in_tags) {
4961 if (cur_id <= good_id)
4963 /* Move to next type */
4965 t = btf_type_by_id(btf, cur_id);
4974 static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
4975 u32 log_level, char __user *log_ubuf, u32 log_size)
4977 struct btf_verifier_env *env = NULL;
4978 struct bpf_verifier_log *log;
4979 struct btf *btf = NULL;
4983 if (btf_data_size > BTF_MAX_SIZE)
4984 return ERR_PTR(-E2BIG);
4986 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4988 return ERR_PTR(-ENOMEM);
4991 if (log_level || log_ubuf || log_size) {
4992 /* user requested verbose verifier output
4993 * and supplied buffer to store the verification trace
4995 log->level = log_level;
4996 log->ubuf = log_ubuf;
4997 log->len_total = log_size;
4999 /* log attributes have to be sane */
5000 if (!bpf_verifier_log_attr_valid(log)) {
5006 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5013 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
5020 btf->data_size = btf_data_size;
5022 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
5027 err = btf_parse_hdr(env);
5031 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5033 err = btf_parse_str_sec(env);
5037 err = btf_parse_type_sec(env);
5041 err = btf_check_type_tags(env, btf, 1);
5045 if (log->level && bpf_verifier_log_full(log)) {
5050 btf_verifier_env_free(env);
5051 refcount_set(&btf->refcnt, 1);
5055 btf_verifier_env_free(env);
5058 return ERR_PTR(err);
5061 extern char __weak __start_BTF[];
5062 extern char __weak __stop_BTF[];
5063 extern struct btf *btf_vmlinux;
5065 #define BPF_MAP_TYPE(_id, _ops)
5066 #define BPF_LINK_TYPE(_id, _name)
5068 struct bpf_ctx_convert {
5069 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5070 prog_ctx_type _id##_prog; \
5071 kern_ctx_type _id##_kern;
5072 #include <linux/bpf_types.h>
5073 #undef BPF_PROG_TYPE
5075 /* 't' is written once under lock. Read many times. */
5076 const struct btf_type *t;
5079 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5081 #include <linux/bpf_types.h>
5082 #undef BPF_PROG_TYPE
5083 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
5085 static u8 bpf_ctx_convert_map[] = {
5086 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
5087 [_id] = __ctx_convert##_id,
5088 #include <linux/bpf_types.h>
5089 #undef BPF_PROG_TYPE
5090 0, /* avoid empty array */
5093 #undef BPF_LINK_TYPE
5095 static const struct btf_member *
5096 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
5097 const struct btf_type *t, enum bpf_prog_type prog_type,
5100 const struct btf_type *conv_struct;
5101 const struct btf_type *ctx_struct;
5102 const struct btf_member *ctx_type;
5103 const char *tname, *ctx_tname;
5105 conv_struct = bpf_ctx_convert.t;
5107 bpf_log(log, "btf_vmlinux is malformed\n");
5110 t = btf_type_by_id(btf, t->type);
5111 while (btf_type_is_modifier(t))
5112 t = btf_type_by_id(btf, t->type);
5113 if (!btf_type_is_struct(t)) {
5114 /* Only pointer to struct is supported for now.
5115 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
5116 * is not supported yet.
5117 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
5121 tname = btf_name_by_offset(btf, t->name_off);
5123 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
5126 /* prog_type is valid bpf program type. No need for bounds check. */
5127 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
5128 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
5129 * Like 'struct __sk_buff'
5131 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
5133 /* should not happen */
5136 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
5138 /* should not happen */
5139 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
5142 /* only compare that prog's ctx type name is the same as
5143 * kernel expects. No need to compare field by field.
5144 * It's ok for bpf prog to do:
5145 * struct __sk_buff {};
5146 * int socket_filter_bpf_prog(struct __sk_buff *skb)
5147 * { // no fields of skb are ever used }
5149 if (strcmp(ctx_tname, tname)) {
5150 /* bpf_user_pt_regs_t is a typedef, so resolve it to
5151 * underlying struct and check name again
5153 if (!btf_type_is_modifier(ctx_struct))
5155 while (btf_type_is_modifier(ctx_struct))
5156 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_struct->type);
5162 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
5164 const struct btf_type *t,
5165 enum bpf_prog_type prog_type,
5168 const struct btf_member *prog_ctx_type, *kern_ctx_type;
5170 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
5173 kern_ctx_type = prog_ctx_type + 1;
5174 return kern_ctx_type->type;
5177 BTF_ID_LIST(bpf_ctx_convert_btf_id)
5178 BTF_ID(struct, bpf_ctx_convert)
5180 struct btf *btf_parse_vmlinux(void)
5182 struct btf_verifier_env *env = NULL;
5183 struct bpf_verifier_log *log;
5184 struct btf *btf = NULL;
5187 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5189 return ERR_PTR(-ENOMEM);
5192 log->level = BPF_LOG_KERNEL;
5194 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5201 btf->data = __start_BTF;
5202 btf->data_size = __stop_BTF - __start_BTF;
5203 btf->kernel_btf = true;
5204 snprintf(btf->name, sizeof(btf->name), "vmlinux");
5206 err = btf_parse_hdr(env);
5210 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5212 err = btf_parse_str_sec(env);
5216 err = btf_check_all_metas(env);
5220 err = btf_check_type_tags(env, btf, 1);
5224 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
5225 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
5227 bpf_struct_ops_init(btf, log);
5229 refcount_set(&btf->refcnt, 1);
5231 err = btf_alloc_id(btf);
5235 btf_verifier_env_free(env);
5239 btf_verifier_env_free(env);
5244 return ERR_PTR(err);
5247 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5249 static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
5251 struct btf_verifier_env *env = NULL;
5252 struct bpf_verifier_log *log;
5253 struct btf *btf = NULL, *base_btf;
5256 base_btf = bpf_get_btf_vmlinux();
5257 if (IS_ERR(base_btf))
5260 return ERR_PTR(-EINVAL);
5262 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5264 return ERR_PTR(-ENOMEM);
5267 log->level = BPF_LOG_KERNEL;
5269 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5276 btf->base_btf = base_btf;
5277 btf->start_id = base_btf->nr_types;
5278 btf->start_str_off = base_btf->hdr.str_len;
5279 btf->kernel_btf = true;
5280 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
5282 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
5287 memcpy(btf->data, data, data_size);
5288 btf->data_size = data_size;
5290 err = btf_parse_hdr(env);
5294 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5296 err = btf_parse_str_sec(env);
5300 err = btf_check_all_metas(env);
5304 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
5308 btf_verifier_env_free(env);
5309 refcount_set(&btf->refcnt, 1);
5313 btf_verifier_env_free(env);
5319 return ERR_PTR(err);
5322 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
5324 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
5326 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5329 return tgt_prog->aux->btf;
5331 return prog->aux->attach_btf;
5334 static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
5336 /* skip modifiers */
5337 t = btf_type_skip_modifiers(btf, t->type, NULL);
5339 return btf_type_is_int(t);
5342 static u32 get_ctx_arg_idx(struct btf *btf, const struct btf_type *func_proto,
5345 const struct btf_param *args;
5346 const struct btf_type *t;
5347 u32 offset = 0, nr_args;
5353 nr_args = btf_type_vlen(func_proto);
5354 args = (const struct btf_param *)(func_proto + 1);
5355 for (i = 0; i < nr_args; i++) {
5356 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5357 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
5362 t = btf_type_skip_modifiers(btf, func_proto->type, NULL);
5363 offset += btf_type_is_ptr(t) ? 8 : roundup(t->size, 8);
5370 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
5371 const struct bpf_prog *prog,
5372 struct bpf_insn_access_aux *info)
5374 const struct btf_type *t = prog->aux->attach_func_proto;
5375 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5376 struct btf *btf = bpf_prog_get_target_btf(prog);
5377 const char *tname = prog->aux->attach_func_name;
5378 struct bpf_verifier_log *log = info->log;
5379 const struct btf_param *args;
5380 const char *tag_value;
5385 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
5389 arg = get_ctx_arg_idx(btf, t, off);
5390 args = (const struct btf_param *)(t + 1);
5391 /* if (t == NULL) Fall back to default BPF prog with
5392 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
5394 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
5395 if (prog->aux->attach_btf_trace) {
5396 /* skip first 'void *__data' argument in btf_trace_##name typedef */
5401 if (arg > nr_args) {
5402 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5407 if (arg == nr_args) {
5408 switch (prog->expected_attach_type) {
5409 case BPF_LSM_CGROUP:
5411 case BPF_TRACE_FEXIT:
5412 /* When LSM programs are attached to void LSM hooks
5413 * they use FEXIT trampolines and when attached to
5414 * int LSM hooks, they use MODIFY_RETURN trampolines.
5416 * While the LSM programs are BPF_MODIFY_RETURN-like
5419 * if (ret_type != 'int')
5422 * is _not_ done here. This is still safe as LSM hooks
5423 * have only void and int return types.
5427 t = btf_type_by_id(btf, t->type);
5429 case BPF_MODIFY_RETURN:
5430 /* For now the BPF_MODIFY_RETURN can only be attached to
5431 * functions that return an int.
5436 t = btf_type_skip_modifiers(btf, t->type, NULL);
5437 if (!btf_type_is_small_int(t)) {
5439 "ret type %s not allowed for fmod_ret\n",
5445 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5451 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
5453 t = btf_type_by_id(btf, args[arg].type);
5456 /* skip modifiers */
5457 while (btf_type_is_modifier(t))
5458 t = btf_type_by_id(btf, t->type);
5459 if (btf_type_is_small_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
5460 /* accessing a scalar */
5462 if (!btf_type_is_ptr(t)) {
5464 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
5466 __btf_name_by_offset(btf, t->name_off),
5471 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
5472 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5473 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5476 type = base_type(ctx_arg_info->reg_type);
5477 flag = type_flag(ctx_arg_info->reg_type);
5478 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
5479 (flag & PTR_MAYBE_NULL)) {
5480 info->reg_type = ctx_arg_info->reg_type;
5486 /* This is a pointer to void.
5487 * It is the same as scalar from the verifier safety pov.
5488 * No further pointer walking is allowed.
5492 if (is_int_ptr(btf, t))
5495 /* this is a pointer to another type */
5496 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5497 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5499 if (ctx_arg_info->offset == off) {
5500 if (!ctx_arg_info->btf_id) {
5501 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
5505 info->reg_type = ctx_arg_info->reg_type;
5506 info->btf = btf_vmlinux;
5507 info->btf_id = ctx_arg_info->btf_id;
5512 info->reg_type = PTR_TO_BTF_ID;
5514 enum bpf_prog_type tgt_type;
5516 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
5517 tgt_type = tgt_prog->aux->saved_dst_prog_type;
5519 tgt_type = tgt_prog->type;
5521 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
5523 info->btf = btf_vmlinux;
5532 info->btf_id = t->type;
5533 t = btf_type_by_id(btf, t->type);
5535 if (btf_type_is_type_tag(t)) {
5536 tag_value = __btf_name_by_offset(btf, t->name_off);
5537 if (strcmp(tag_value, "user") == 0)
5538 info->reg_type |= MEM_USER;
5539 if (strcmp(tag_value, "percpu") == 0)
5540 info->reg_type |= MEM_PERCPU;
5543 /* skip modifiers */
5544 while (btf_type_is_modifier(t)) {
5545 info->btf_id = t->type;
5546 t = btf_type_by_id(btf, t->type);
5548 if (!btf_type_is_struct(t)) {
5550 "func '%s' arg%d type %s is not a struct\n",
5551 tname, arg, btf_type_str(t));
5554 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
5555 tname, arg, info->btf_id, btf_type_str(t),
5556 __btf_name_by_offset(btf, t->name_off));
5560 enum bpf_struct_walk_result {
5567 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
5568 const struct btf_type *t, int off, int size,
5569 u32 *next_btf_id, enum bpf_type_flag *flag)
5571 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
5572 const struct btf_type *mtype, *elem_type = NULL;
5573 const struct btf_member *member;
5574 const char *tname, *mname, *tag_value;
5575 u32 vlen, elem_id, mid;
5578 tname = __btf_name_by_offset(btf, t->name_off);
5579 if (!btf_type_is_struct(t)) {
5580 bpf_log(log, "Type '%s' is not a struct\n", tname);
5584 vlen = btf_type_vlen(t);
5585 if (off + size > t->size) {
5586 /* If the last element is a variable size array, we may
5587 * need to relax the rule.
5589 struct btf_array *array_elem;
5594 member = btf_type_member(t) + vlen - 1;
5595 mtype = btf_type_skip_modifiers(btf, member->type,
5597 if (!btf_type_is_array(mtype))
5600 array_elem = (struct btf_array *)(mtype + 1);
5601 if (array_elem->nelems != 0)
5604 moff = __btf_member_bit_offset(t, member) / 8;
5608 /* Only allow structure for now, can be relaxed for
5609 * other types later.
5611 t = btf_type_skip_modifiers(btf, array_elem->type,
5613 if (!btf_type_is_struct(t))
5616 off = (off - moff) % t->size;
5620 bpf_log(log, "access beyond struct %s at off %u size %u\n",
5625 for_each_member(i, t, member) {
5626 /* offset of the field in bytes */
5627 moff = __btf_member_bit_offset(t, member) / 8;
5628 if (off + size <= moff)
5629 /* won't find anything, field is already too far */
5632 if (__btf_member_bitfield_size(t, member)) {
5633 u32 end_bit = __btf_member_bit_offset(t, member) +
5634 __btf_member_bitfield_size(t, member);
5636 /* off <= moff instead of off == moff because clang
5637 * does not generate a BTF member for anonymous
5638 * bitfield like the ":16" here:
5645 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
5648 /* off may be accessing a following member
5652 * Doing partial access at either end of this
5653 * bitfield. Continue on this case also to
5654 * treat it as not accessing this bitfield
5655 * and eventually error out as field not
5656 * found to keep it simple.
5657 * It could be relaxed if there was a legit
5658 * partial access case later.
5663 /* In case of "off" is pointing to holes of a struct */
5667 /* type of the field */
5669 mtype = btf_type_by_id(btf, member->type);
5670 mname = __btf_name_by_offset(btf, member->name_off);
5672 mtype = __btf_resolve_size(btf, mtype, &msize,
5673 &elem_type, &elem_id, &total_nelems,
5675 if (IS_ERR(mtype)) {
5676 bpf_log(log, "field %s doesn't have size\n", mname);
5680 mtrue_end = moff + msize;
5681 if (off >= mtrue_end)
5682 /* no overlap with member, keep iterating */
5685 if (btf_type_is_array(mtype)) {
5688 /* __btf_resolve_size() above helps to
5689 * linearize a multi-dimensional array.
5691 * The logic here is treating an array
5692 * in a struct as the following way:
5695 * struct inner array[2][2];
5701 * struct inner array_elem0;
5702 * struct inner array_elem1;
5703 * struct inner array_elem2;
5704 * struct inner array_elem3;
5707 * When accessing outer->array[1][0], it moves
5708 * moff to "array_elem2", set mtype to
5709 * "struct inner", and msize also becomes
5710 * sizeof(struct inner). Then most of the
5711 * remaining logic will fall through without
5712 * caring the current member is an array or
5715 * Unlike mtype/msize/moff, mtrue_end does not
5716 * change. The naming difference ("_true") tells
5717 * that it is not always corresponding to
5718 * the current mtype/msize/moff.
5719 * It is the true end of the current
5720 * member (i.e. array in this case). That
5721 * will allow an int array to be accessed like
5723 * i.e. allow access beyond the size of
5724 * the array's element as long as it is
5725 * within the mtrue_end boundary.
5728 /* skip empty array */
5729 if (moff == mtrue_end)
5732 msize /= total_nelems;
5733 elem_idx = (off - moff) / msize;
5734 moff += elem_idx * msize;
5739 /* the 'off' we're looking for is either equal to start
5740 * of this field or inside of this struct
5742 if (btf_type_is_struct(mtype)) {
5743 /* our field must be inside that union or struct */
5746 /* return if the offset matches the member offset */
5752 /* adjust offset we're looking for */
5757 if (btf_type_is_ptr(mtype)) {
5758 const struct btf_type *stype, *t;
5759 enum bpf_type_flag tmp_flag = 0;
5762 if (msize != size || off != moff) {
5764 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
5765 mname, moff, tname, off, size);
5769 /* check type tag */
5770 t = btf_type_by_id(btf, mtype->type);
5771 if (btf_type_is_type_tag(t)) {
5772 tag_value = __btf_name_by_offset(btf, t->name_off);
5773 /* check __user tag */
5774 if (strcmp(tag_value, "user") == 0)
5775 tmp_flag = MEM_USER;
5776 /* check __percpu tag */
5777 if (strcmp(tag_value, "percpu") == 0)
5778 tmp_flag = MEM_PERCPU;
5781 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
5782 if (btf_type_is_struct(stype)) {
5789 /* Allow more flexible access within an int as long as
5790 * it is within mtrue_end.
5791 * Since mtrue_end could be the end of an array,
5792 * that also allows using an array of int as a scratch
5793 * space. e.g. skb->cb[].
5795 if (off + size > mtrue_end) {
5797 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
5798 mname, mtrue_end, tname, off, size);
5804 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
5808 int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
5809 const struct btf_type *t, int off, int size,
5810 enum bpf_access_type atype __maybe_unused,
5811 u32 *next_btf_id, enum bpf_type_flag *flag)
5813 enum bpf_type_flag tmp_flag = 0;
5818 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
5822 /* If we found the pointer or scalar on t+off,
5827 return PTR_TO_BTF_ID;
5829 return SCALAR_VALUE;
5831 /* We found nested struct, so continue the search
5832 * by diving in it. At this point the offset is
5833 * aligned with the new type, so set it to 0.
5835 t = btf_type_by_id(btf, id);
5839 /* It's either error or unknown return value..
5842 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
5851 /* Check that two BTF types, each specified as an BTF object + id, are exactly
5852 * the same. Trivial ID check is not enough due to module BTFs, because we can
5853 * end up with two different module BTFs, but IDs point to the common type in
5856 static bool btf_types_are_same(const struct btf *btf1, u32 id1,
5857 const struct btf *btf2, u32 id2)
5863 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
5866 bool btf_struct_ids_match(struct bpf_verifier_log *log,
5867 const struct btf *btf, u32 id, int off,
5868 const struct btf *need_btf, u32 need_type_id,
5871 const struct btf_type *type;
5872 enum bpf_type_flag flag;
5875 /* Are we already done? */
5876 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
5878 /* In case of strict type match, we do not walk struct, the top level
5879 * type match must succeed. When strict is true, off should have already
5885 type = btf_type_by_id(btf, id);
5888 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag);
5889 if (err != WALK_STRUCT)
5892 /* We found nested struct object. If it matches
5893 * the requested ID, we're done. Otherwise let's
5894 * continue the search with offset 0 in the new
5897 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
5905 static int __get_type_size(struct btf *btf, u32 btf_id,
5906 const struct btf_type **ret_type)
5908 const struct btf_type *t;
5910 *ret_type = btf_type_by_id(btf, 0);
5914 t = btf_type_by_id(btf, btf_id);
5915 while (t && btf_type_is_modifier(t))
5916 t = btf_type_by_id(btf, t->type);
5920 if (btf_type_is_ptr(t))
5921 /* kernel size of pointer. Not BPF's size of pointer*/
5922 return sizeof(void *);
5923 if (btf_type_is_int(t) || btf_is_any_enum(t) || __btf_type_is_struct(t))
5928 int btf_distill_func_proto(struct bpf_verifier_log *log,
5930 const struct btf_type *func,
5932 struct btf_func_model *m)
5934 const struct btf_param *args;
5935 const struct btf_type *t;
5940 /* BTF function prototype doesn't match the verifier types.
5941 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
5943 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
5945 m->arg_flags[i] = 0;
5948 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
5951 args = (const struct btf_param *)(func + 1);
5952 nargs = btf_type_vlen(func);
5953 if (nargs > MAX_BPF_FUNC_ARGS) {
5955 "The function %s has %d arguments. Too many.\n",
5959 ret = __get_type_size(btf, func->type, &t);
5960 if (ret < 0 || __btf_type_is_struct(t)) {
5962 "The function %s return type %s is unsupported.\n",
5963 tname, btf_type_str(t));
5968 for (i = 0; i < nargs; i++) {
5969 if (i == nargs - 1 && args[i].type == 0) {
5971 "The function %s with variable args is unsupported.\n",
5975 ret = __get_type_size(btf, args[i].type, &t);
5977 /* No support of struct argument size greater than 16 bytes */
5978 if (ret < 0 || ret > 16) {
5980 "The function %s arg%d type %s is unsupported.\n",
5981 tname, i, btf_type_str(t));
5986 "The function %s has malformed void argument.\n",
5990 m->arg_size[i] = ret;
5991 m->arg_flags[i] = __btf_type_is_struct(t) ? BTF_FMODEL_STRUCT_ARG : 0;
5997 /* Compare BTFs of two functions assuming only scalars and pointers to context.
5998 * t1 points to BTF_KIND_FUNC in btf1
5999 * t2 points to BTF_KIND_FUNC in btf2
6001 * EINVAL - function prototype mismatch
6002 * EFAULT - verifier bug
6003 * 0 - 99% match. The last 1% is validated by the verifier.
6005 static int btf_check_func_type_match(struct bpf_verifier_log *log,
6006 struct btf *btf1, const struct btf_type *t1,
6007 struct btf *btf2, const struct btf_type *t2)
6009 const struct btf_param *args1, *args2;
6010 const char *fn1, *fn2, *s1, *s2;
6011 u32 nargs1, nargs2, i;
6013 fn1 = btf_name_by_offset(btf1, t1->name_off);
6014 fn2 = btf_name_by_offset(btf2, t2->name_off);
6016 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
6017 bpf_log(log, "%s() is not a global function\n", fn1);
6020 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
6021 bpf_log(log, "%s() is not a global function\n", fn2);
6025 t1 = btf_type_by_id(btf1, t1->type);
6026 if (!t1 || !btf_type_is_func_proto(t1))
6028 t2 = btf_type_by_id(btf2, t2->type);
6029 if (!t2 || !btf_type_is_func_proto(t2))
6032 args1 = (const struct btf_param *)(t1 + 1);
6033 nargs1 = btf_type_vlen(t1);
6034 args2 = (const struct btf_param *)(t2 + 1);
6035 nargs2 = btf_type_vlen(t2);
6037 if (nargs1 != nargs2) {
6038 bpf_log(log, "%s() has %d args while %s() has %d args\n",
6039 fn1, nargs1, fn2, nargs2);
6043 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6044 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6045 if (t1->info != t2->info) {
6047 "Return type %s of %s() doesn't match type %s of %s()\n",
6048 btf_type_str(t1), fn1,
6049 btf_type_str(t2), fn2);
6053 for (i = 0; i < nargs1; i++) {
6054 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
6055 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
6057 if (t1->info != t2->info) {
6058 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
6059 i, fn1, btf_type_str(t1),
6060 fn2, btf_type_str(t2));
6063 if (btf_type_has_size(t1) && t1->size != t2->size) {
6065 "arg%d in %s() has size %d while %s() has %d\n",
6071 /* global functions are validated with scalars and pointers
6072 * to context only. And only global functions can be replaced.
6073 * Hence type check only those types.
6075 if (btf_type_is_int(t1) || btf_is_any_enum(t1))
6077 if (!btf_type_is_ptr(t1)) {
6079 "arg%d in %s() has unrecognized type\n",
6083 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
6084 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
6085 if (!btf_type_is_struct(t1)) {
6087 "arg%d in %s() is not a pointer to context\n",
6091 if (!btf_type_is_struct(t2)) {
6093 "arg%d in %s() is not a pointer to context\n",
6097 /* This is an optional check to make program writing easier.
6098 * Compare names of structs and report an error to the user.
6099 * btf_prepare_func_args() already checked that t2 struct
6100 * is a context type. btf_prepare_func_args() will check
6101 * later that t1 struct is a context type as well.
6103 s1 = btf_name_by_offset(btf1, t1->name_off);
6104 s2 = btf_name_by_offset(btf2, t2->name_off);
6105 if (strcmp(s1, s2)) {
6107 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
6108 i, fn1, s1, fn2, s2);
6115 /* Compare BTFs of given program with BTF of target program */
6116 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
6117 struct btf *btf2, const struct btf_type *t2)
6119 struct btf *btf1 = prog->aux->btf;
6120 const struct btf_type *t1;
6123 if (!prog->aux->func_info) {
6124 bpf_log(log, "Program extension requires BTF\n");
6128 btf_id = prog->aux->func_info[0].type_id;
6132 t1 = btf_type_by_id(btf1, btf_id);
6133 if (!t1 || !btf_type_is_func(t1))
6136 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
6139 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
6141 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
6142 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
6143 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
6147 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
6148 static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
6149 const struct btf *btf,
6150 const struct btf_type *t, int rec)
6152 const struct btf_type *member_type;
6153 const struct btf_member *member;
6156 if (!btf_type_is_struct(t))
6159 for_each_member(i, t, member) {
6160 const struct btf_array *array;
6162 member_type = btf_type_skip_modifiers(btf, member->type, NULL);
6163 if (btf_type_is_struct(member_type)) {
6165 bpf_log(log, "max struct nesting depth exceeded\n");
6168 if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
6172 if (btf_type_is_array(member_type)) {
6173 array = btf_type_array(member_type);
6176 member_type = btf_type_skip_modifiers(btf, array->type, NULL);
6177 if (!btf_type_is_scalar(member_type))
6181 if (!btf_type_is_scalar(member_type))
6187 static bool is_kfunc_arg_mem_size(const struct btf *btf,
6188 const struct btf_param *arg,
6189 const struct bpf_reg_state *reg)
6191 int len, sfx_len = sizeof("__sz") - 1;
6192 const struct btf_type *t;
6193 const char *param_name;
6195 t = btf_type_skip_modifiers(btf, arg->type, NULL);
6196 if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
6199 /* In the future, this can be ported to use BTF tagging */
6200 param_name = btf_name_by_offset(btf, arg->name_off);
6201 if (str_is_empty(param_name))
6203 len = strlen(param_name);
6206 param_name += len - sfx_len;
6207 if (strncmp(param_name, "__sz", sfx_len))
6213 static bool btf_is_kfunc_arg_mem_size(const struct btf *btf,
6214 const struct btf_param *arg,
6215 const struct bpf_reg_state *reg,
6218 int len, target_len = strlen(name);
6219 const struct btf_type *t;
6220 const char *param_name;
6222 t = btf_type_skip_modifiers(btf, arg->type, NULL);
6223 if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
6226 param_name = btf_name_by_offset(btf, arg->name_off);
6227 if (str_is_empty(param_name))
6229 len = strlen(param_name);
6230 if (len != target_len)
6232 if (strcmp(param_name, name))
6238 static int btf_check_func_arg_match(struct bpf_verifier_env *env,
6239 const struct btf *btf, u32 func_id,
6240 struct bpf_reg_state *regs,
6242 struct bpf_kfunc_arg_meta *kfunc_meta,
6243 bool processing_call)
6245 enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
6246 bool rel = false, kptr_get = false, trusted_args = false;
6247 bool sleepable = false;
6248 struct bpf_verifier_log *log = &env->log;
6249 u32 i, nargs, ref_id, ref_obj_id = 0;
6250 bool is_kfunc = btf_is_kernel(btf);
6251 const char *func_name, *ref_tname;
6252 const struct btf_type *t, *ref_t;
6253 const struct btf_param *args;
6254 int ref_regno = 0, ret;
6256 t = btf_type_by_id(btf, func_id);
6257 if (!t || !btf_type_is_func(t)) {
6258 /* These checks were already done by the verifier while loading
6259 * struct bpf_func_info or in add_kfunc_call().
6261 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
6265 func_name = btf_name_by_offset(btf, t->name_off);
6267 t = btf_type_by_id(btf, t->type);
6268 if (!t || !btf_type_is_func_proto(t)) {
6269 bpf_log(log, "Invalid BTF of func %s\n", func_name);
6272 args = (const struct btf_param *)(t + 1);
6273 nargs = btf_type_vlen(t);
6274 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6275 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
6276 MAX_BPF_FUNC_REG_ARGS);
6280 if (is_kfunc && kfunc_meta) {
6281 /* Only kfunc can be release func */
6282 rel = kfunc_meta->flags & KF_RELEASE;
6283 kptr_get = kfunc_meta->flags & KF_KPTR_GET;
6284 trusted_args = kfunc_meta->flags & KF_TRUSTED_ARGS;
6285 sleepable = kfunc_meta->flags & KF_SLEEPABLE;
6288 /* check that BTF function arguments match actual types that the
6291 for (i = 0; i < nargs; i++) {
6292 enum bpf_arg_type arg_type = ARG_DONTCARE;
6294 struct bpf_reg_state *reg = ®s[regno];
6295 bool obj_ptr = false;
6297 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6298 if (btf_type_is_scalar(t)) {
6299 if (is_kfunc && kfunc_meta) {
6300 bool is_buf_size = false;
6302 /* check for any const scalar parameter of name "rdonly_buf_size"
6303 * or "rdwr_buf_size"
6305 if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
6306 "rdonly_buf_size")) {
6307 kfunc_meta->r0_rdonly = true;
6309 } else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
6314 if (kfunc_meta->r0_size) {
6315 bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
6319 if (!tnum_is_const(reg->var_off)) {
6320 bpf_log(log, "R%d is not a const\n", regno);
6324 kfunc_meta->r0_size = reg->var_off.value;
6325 ret = mark_chain_precision(env, regno);
6331 if (reg->type == SCALAR_VALUE)
6333 bpf_log(log, "R%d is not a scalar\n", regno);
6337 if (!btf_type_is_ptr(t)) {
6338 bpf_log(log, "Unrecognized arg#%d type %s\n",
6339 i, btf_type_str(t));
6343 /* These register types have special constraints wrt ref_obj_id
6344 * and offset checks. The rest of trusted args don't.
6346 obj_ptr = reg->type == PTR_TO_CTX || reg->type == PTR_TO_BTF_ID ||
6347 reg2btf_ids[base_type(reg->type)];
6349 /* Check if argument must be a referenced pointer, args + i has
6350 * been verified to be a pointer (after skipping modifiers).
6351 * PTR_TO_CTX is ok without having non-zero ref_obj_id.
6353 if (is_kfunc && trusted_args && (obj_ptr && reg->type != PTR_TO_CTX) && !reg->ref_obj_id) {
6354 bpf_log(log, "R%d must be referenced\n", regno);
6358 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
6359 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
6361 /* Trusted args have the same offset checks as release arguments */
6362 if ((trusted_args && obj_ptr) || (rel && reg->ref_obj_id))
6363 arg_type |= OBJ_RELEASE;
6364 ret = check_func_arg_reg_off(env, reg, regno, arg_type);
6368 if (is_kfunc && reg->ref_obj_id) {
6369 /* Ensure only one argument is referenced PTR_TO_BTF_ID */
6371 bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
6372 regno, reg->ref_obj_id, ref_obj_id);
6376 ref_obj_id = reg->ref_obj_id;
6379 /* kptr_get is only true for kfunc */
6380 if (i == 0 && kptr_get) {
6381 struct bpf_map_value_off_desc *off_desc;
6383 if (reg->type != PTR_TO_MAP_VALUE) {
6384 bpf_log(log, "arg#0 expected pointer to map value\n");
6388 /* check_func_arg_reg_off allows var_off for
6389 * PTR_TO_MAP_VALUE, but we need fixed offset to find
6392 if (!tnum_is_const(reg->var_off)) {
6393 bpf_log(log, "arg#0 must have constant offset\n");
6397 off_desc = bpf_map_kptr_off_contains(reg->map_ptr, reg->off + reg->var_off.value);
6398 if (!off_desc || off_desc->type != BPF_KPTR_REF) {
6399 bpf_log(log, "arg#0 no referenced kptr at map value offset=%llu\n",
6400 reg->off + reg->var_off.value);
6404 if (!btf_type_is_ptr(ref_t)) {
6405 bpf_log(log, "arg#0 BTF type must be a double pointer\n");
6409 ref_t = btf_type_skip_modifiers(btf, ref_t->type, &ref_id);
6410 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
6412 if (!btf_type_is_struct(ref_t)) {
6413 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
6414 func_name, i, btf_type_str(ref_t), ref_tname);
6417 if (!btf_struct_ids_match(log, btf, ref_id, 0, off_desc->kptr.btf,
6418 off_desc->kptr.btf_id, true)) {
6419 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s\n",
6420 func_name, i, btf_type_str(ref_t), ref_tname);
6423 /* rest of the arguments can be anything, like normal kfunc */
6424 } else if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6425 /* If function expects ctx type in BTF check that caller
6426 * is passing PTR_TO_CTX.
6428 if (reg->type != PTR_TO_CTX) {
6430 "arg#%d expected pointer to ctx, but got %s\n",
6431 i, btf_type_str(t));
6434 } else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
6435 (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
6436 const struct btf_type *reg_ref_t;
6437 const struct btf *reg_btf;
6438 const char *reg_ref_tname;
6441 if (!btf_type_is_struct(ref_t)) {
6442 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
6443 func_name, i, btf_type_str(ref_t),
6448 if (reg->type == PTR_TO_BTF_ID) {
6450 reg_ref_id = reg->btf_id;
6452 reg_btf = btf_vmlinux;
6453 reg_ref_id = *reg2btf_ids[base_type(reg->type)];
6456 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
6458 reg_ref_tname = btf_name_by_offset(reg_btf,
6459 reg_ref_t->name_off);
6460 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
6461 reg->off, btf, ref_id,
6462 trusted_args || (rel && reg->ref_obj_id))) {
6463 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
6465 btf_type_str(ref_t), ref_tname,
6466 regno, btf_type_str(reg_ref_t),
6470 } else if (ptr_to_mem_ok && processing_call) {
6471 const struct btf_type *resolve_ret;
6475 bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]);
6476 bool arg_dynptr = btf_type_is_struct(ref_t) &&
6478 stringify_struct(bpf_dynptr_kern));
6480 /* Permit pointer to mem, but only when argument
6481 * type is pointer to scalar, or struct composed
6482 * (recursively) of scalars.
6483 * When arg_mem_size is true, the pointer can be
6485 * Also permit initialized local dynamic pointers.
6487 if (!btf_type_is_scalar(ref_t) &&
6488 !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
6490 (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
6492 "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
6493 i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
6498 if (reg->type != PTR_TO_STACK) {
6499 bpf_log(log, "arg#%d pointer type %s %s not to stack\n",
6500 i, btf_type_str(ref_t),
6505 if (!is_dynptr_reg_valid_init(env, reg)) {
6507 "arg#%d pointer type %s %s must be valid and initialized\n",
6508 i, btf_type_str(ref_t),
6513 if (!is_dynptr_type_expected(env, reg,
6514 ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
6516 "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
6517 i, btf_type_str(ref_t),
6525 /* Check for mem, len pair */
6527 if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) {
6528 bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
6537 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
6538 if (IS_ERR(resolve_ret)) {
6540 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6541 i, btf_type_str(ref_t), ref_tname,
6542 PTR_ERR(resolve_ret));
6546 if (check_mem_reg(env, reg, regno, type_size))
6549 bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
6550 is_kfunc ? "kernel " : "", func_name, func_id);
6555 /* Either both are set, or neither */
6556 WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
6557 /* We already made sure ref_obj_id is set only for one argument. We do
6558 * allow (!rel && ref_obj_id), so that passing such referenced
6559 * PTR_TO_BTF_ID to other kfuncs works. Note that rel is only true when
6562 if (rel && !ref_obj_id) {
6563 bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
6568 if (sleepable && !env->prog->aux->sleepable) {
6569 bpf_log(log, "kernel function %s is sleepable but the program is not\n",
6574 if (kfunc_meta && ref_obj_id)
6575 kfunc_meta->ref_obj_id = ref_obj_id;
6577 /* returns argument register number > 0 in case of reference release kfunc */
6578 return rel ? ref_regno : 0;
6581 /* Compare BTF of a function declaration with given bpf_reg_state.
6583 * EFAULT - there is a verifier bug. Abort verification.
6584 * EINVAL - there is a type mismatch or BTF is not available.
6585 * 0 - BTF matches with what bpf_reg_state expects.
6586 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6588 int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
6589 struct bpf_reg_state *regs)
6591 struct bpf_prog *prog = env->prog;
6592 struct btf *btf = prog->aux->btf;
6597 if (!prog->aux->func_info)
6600 btf_id = prog->aux->func_info[subprog].type_id;
6604 if (prog->aux->func_info_aux[subprog].unreliable)
6607 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6608 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false);
6610 /* Compiler optimizations can remove arguments from static functions
6611 * or mismatched type can be passed into a global function.
6612 * In such cases mark the function as unreliable from BTF point of view.
6615 prog->aux->func_info_aux[subprog].unreliable = true;
6619 /* Compare BTF of a function call with given bpf_reg_state.
6621 * EFAULT - there is a verifier bug. Abort verification.
6622 * EINVAL - there is a type mismatch or BTF is not available.
6623 * 0 - BTF matches with what bpf_reg_state expects.
6624 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6626 * NOTE: the code is duplicated from btf_check_subprog_arg_match()
6627 * because btf_check_func_arg_match() is still doing both. Once that
6628 * function is split in 2, we can call from here btf_check_subprog_arg_match()
6629 * first, and then treat the calling part in a new code path.
6631 int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
6632 struct bpf_reg_state *regs)
6634 struct bpf_prog *prog = env->prog;
6635 struct btf *btf = prog->aux->btf;
6640 if (!prog->aux->func_info)
6643 btf_id = prog->aux->func_info[subprog].type_id;
6647 if (prog->aux->func_info_aux[subprog].unreliable)
6650 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6651 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true);
6653 /* Compiler optimizations can remove arguments from static functions
6654 * or mismatched type can be passed into a global function.
6655 * In such cases mark the function as unreliable from BTF point of view.
6658 prog->aux->func_info_aux[subprog].unreliable = true;
6662 int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
6663 const struct btf *btf, u32 func_id,
6664 struct bpf_reg_state *regs,
6665 struct bpf_kfunc_arg_meta *meta)
6667 return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true);
6670 /* Convert BTF of a function into bpf_reg_state if possible
6672 * EFAULT - there is a verifier bug. Abort verification.
6673 * EINVAL - cannot convert BTF.
6674 * 0 - Successfully converted BTF into bpf_reg_state
6675 * (either PTR_TO_CTX or SCALAR_VALUE).
6677 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
6678 struct bpf_reg_state *regs)
6680 struct bpf_verifier_log *log = &env->log;
6681 struct bpf_prog *prog = env->prog;
6682 enum bpf_prog_type prog_type = prog->type;
6683 struct btf *btf = prog->aux->btf;
6684 const struct btf_param *args;
6685 const struct btf_type *t, *ref_t;
6686 u32 i, nargs, btf_id;
6689 if (!prog->aux->func_info ||
6690 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
6691 bpf_log(log, "Verifier bug\n");
6695 btf_id = prog->aux->func_info[subprog].type_id;
6697 bpf_log(log, "Global functions need valid BTF\n");
6701 t = btf_type_by_id(btf, btf_id);
6702 if (!t || !btf_type_is_func(t)) {
6703 /* These checks were already done by the verifier while loading
6704 * struct bpf_func_info
6706 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
6710 tname = btf_name_by_offset(btf, t->name_off);
6712 if (log->level & BPF_LOG_LEVEL)
6713 bpf_log(log, "Validating %s() func#%d...\n",
6716 if (prog->aux->func_info_aux[subprog].unreliable) {
6717 bpf_log(log, "Verifier bug in function %s()\n", tname);
6720 if (prog_type == BPF_PROG_TYPE_EXT)
6721 prog_type = prog->aux->dst_prog->type;
6723 t = btf_type_by_id(btf, t->type);
6724 if (!t || !btf_type_is_func_proto(t)) {
6725 bpf_log(log, "Invalid type of function %s()\n", tname);
6728 args = (const struct btf_param *)(t + 1);
6729 nargs = btf_type_vlen(t);
6730 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6731 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
6732 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
6735 /* check that function returns int */
6736 t = btf_type_by_id(btf, t->type);
6737 while (btf_type_is_modifier(t))
6738 t = btf_type_by_id(btf, t->type);
6739 if (!btf_type_is_int(t) && !btf_is_any_enum(t)) {
6741 "Global function %s() doesn't return scalar. Only those are supported.\n",
6745 /* Convert BTF function arguments into verifier types.
6746 * Only PTR_TO_CTX and SCALAR are supported atm.
6748 for (i = 0; i < nargs; i++) {
6749 struct bpf_reg_state *reg = ®s[i + 1];
6751 t = btf_type_by_id(btf, args[i].type);
6752 while (btf_type_is_modifier(t))
6753 t = btf_type_by_id(btf, t->type);
6754 if (btf_type_is_int(t) || btf_is_any_enum(t)) {
6755 reg->type = SCALAR_VALUE;
6758 if (btf_type_is_ptr(t)) {
6759 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6760 reg->type = PTR_TO_CTX;
6764 t = btf_type_skip_modifiers(btf, t->type, NULL);
6766 ref_t = btf_resolve_size(btf, t, ®->mem_size);
6767 if (IS_ERR(ref_t)) {
6769 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6770 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
6775 reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
6776 reg->id = ++env->id_gen;
6780 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
6781 i, btf_type_str(t), tname);
6787 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
6788 struct btf_show *show)
6790 const struct btf_type *t = btf_type_by_id(btf, type_id);
6793 memset(&show->state, 0, sizeof(show->state));
6794 memset(&show->obj, 0, sizeof(show->obj));
6796 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
6799 static void btf_seq_show(struct btf_show *show, const char *fmt,
6802 seq_vprintf((struct seq_file *)show->target, fmt, args);
6805 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
6806 void *obj, struct seq_file *m, u64 flags)
6808 struct btf_show sseq;
6811 sseq.showfn = btf_seq_show;
6814 btf_type_show(btf, type_id, obj, &sseq);
6816 return sseq.state.status;
6819 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
6822 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
6823 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
6824 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
6827 struct btf_show_snprintf {
6828 struct btf_show show;
6829 int len_left; /* space left in string */
6830 int len; /* length we would have written */
6833 static void btf_snprintf_show(struct btf_show *show, const char *fmt,
6836 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
6839 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
6842 ssnprintf->len_left = 0;
6843 ssnprintf->len = len;
6844 } else if (len >= ssnprintf->len_left) {
6845 /* no space, drive on to get length we would have written */
6846 ssnprintf->len_left = 0;
6847 ssnprintf->len += len;
6849 ssnprintf->len_left -= len;
6850 ssnprintf->len += len;
6851 show->target += len;
6855 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
6856 char *buf, int len, u64 flags)
6858 struct btf_show_snprintf ssnprintf;
6860 ssnprintf.show.target = buf;
6861 ssnprintf.show.flags = flags;
6862 ssnprintf.show.showfn = btf_snprintf_show;
6863 ssnprintf.len_left = len;
6866 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
6868 /* If we encountered an error, return it. */
6869 if (ssnprintf.show.state.status)
6870 return ssnprintf.show.state.status;
6872 /* Otherwise return length we would have written */
6873 return ssnprintf.len;
6876 #ifdef CONFIG_PROC_FS
6877 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
6879 const struct btf *btf = filp->private_data;
6881 seq_printf(m, "btf_id:\t%u\n", btf->id);
6885 static int btf_release(struct inode *inode, struct file *filp)
6887 btf_put(filp->private_data);
6891 const struct file_operations btf_fops = {
6892 #ifdef CONFIG_PROC_FS
6893 .show_fdinfo = bpf_btf_show_fdinfo,
6895 .release = btf_release,
6898 static int __btf_new_fd(struct btf *btf)
6900 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
6903 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
6908 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
6909 attr->btf_size, attr->btf_log_level,
6910 u64_to_user_ptr(attr->btf_log_buf),
6911 attr->btf_log_size);
6913 return PTR_ERR(btf);
6915 ret = btf_alloc_id(btf);
6922 * The BTF ID is published to the userspace.
6923 * All BTF free must go through call_rcu() from
6924 * now on (i.e. free by calling btf_put()).
6927 ret = __btf_new_fd(btf);
6934 struct btf *btf_get_by_fd(int fd)
6942 return ERR_PTR(-EBADF);
6944 if (f.file->f_op != &btf_fops) {
6946 return ERR_PTR(-EINVAL);
6949 btf = f.file->private_data;
6950 refcount_inc(&btf->refcnt);
6956 int btf_get_info_by_fd(const struct btf *btf,
6957 const union bpf_attr *attr,
6958 union bpf_attr __user *uattr)
6960 struct bpf_btf_info __user *uinfo;
6961 struct bpf_btf_info info;
6962 u32 info_copy, btf_copy;
6965 u32 uinfo_len, uname_len, name_len;
6968 uinfo = u64_to_user_ptr(attr->info.info);
6969 uinfo_len = attr->info.info_len;
6971 info_copy = min_t(u32, uinfo_len, sizeof(info));
6972 memset(&info, 0, sizeof(info));
6973 if (copy_from_user(&info, uinfo, info_copy))
6977 ubtf = u64_to_user_ptr(info.btf);
6978 btf_copy = min_t(u32, btf->data_size, info.btf_size);
6979 if (copy_to_user(ubtf, btf->data, btf_copy))
6981 info.btf_size = btf->data_size;
6983 info.kernel_btf = btf->kernel_btf;
6985 uname = u64_to_user_ptr(info.name);
6986 uname_len = info.name_len;
6987 if (!uname ^ !uname_len)
6990 name_len = strlen(btf->name);
6991 info.name_len = name_len;
6994 if (uname_len >= name_len + 1) {
6995 if (copy_to_user(uname, btf->name, name_len + 1))
7000 if (copy_to_user(uname, btf->name, uname_len - 1))
7002 if (put_user(zero, uname + uname_len - 1))
7004 /* let user-space know about too short buffer */
7009 if (copy_to_user(uinfo, &info, info_copy) ||
7010 put_user(info_copy, &uattr->info.info_len))
7016 int btf_get_fd_by_id(u32 id)
7022 btf = idr_find(&btf_idr, id);
7023 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
7024 btf = ERR_PTR(-ENOENT);
7028 return PTR_ERR(btf);
7030 fd = __btf_new_fd(btf);
7037 u32 btf_obj_id(const struct btf *btf)
7042 bool btf_is_kernel(const struct btf *btf)
7044 return btf->kernel_btf;
7047 bool btf_is_module(const struct btf *btf)
7049 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
7052 static int btf_id_cmp_func(const void *a, const void *b)
7054 const int *pa = a, *pb = b;
7059 bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
7061 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
7064 static void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
7066 return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
7070 BTF_MODULE_F_LIVE = (1 << 0),
7073 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7075 struct list_head list;
7076 struct module *module;
7078 struct bin_attribute *sysfs_attr;
7082 static LIST_HEAD(btf_modules);
7083 static DEFINE_MUTEX(btf_module_mutex);
7086 btf_module_read(struct file *file, struct kobject *kobj,
7087 struct bin_attribute *bin_attr,
7088 char *buf, loff_t off, size_t len)
7090 const struct btf *btf = bin_attr->private;
7092 memcpy(buf, btf->data + off, len);
7096 static void purge_cand_cache(struct btf *btf);
7098 static int btf_module_notify(struct notifier_block *nb, unsigned long op,
7101 struct btf_module *btf_mod, *tmp;
7102 struct module *mod = module;
7106 if (mod->btf_data_size == 0 ||
7107 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
7108 op != MODULE_STATE_GOING))
7112 case MODULE_STATE_COMING:
7113 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
7118 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
7120 pr_warn("failed to validate module [%s] BTF: %ld\n",
7121 mod->name, PTR_ERR(btf));
7123 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
7127 err = btf_alloc_id(btf);
7134 purge_cand_cache(NULL);
7135 mutex_lock(&btf_module_mutex);
7136 btf_mod->module = module;
7138 list_add(&btf_mod->list, &btf_modules);
7139 mutex_unlock(&btf_module_mutex);
7141 if (IS_ENABLED(CONFIG_SYSFS)) {
7142 struct bin_attribute *attr;
7144 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
7148 sysfs_bin_attr_init(attr);
7149 attr->attr.name = btf->name;
7150 attr->attr.mode = 0444;
7151 attr->size = btf->data_size;
7152 attr->private = btf;
7153 attr->read = btf_module_read;
7155 err = sysfs_create_bin_file(btf_kobj, attr);
7157 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
7164 btf_mod->sysfs_attr = attr;
7168 case MODULE_STATE_LIVE:
7169 mutex_lock(&btf_module_mutex);
7170 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7171 if (btf_mod->module != module)
7174 btf_mod->flags |= BTF_MODULE_F_LIVE;
7177 mutex_unlock(&btf_module_mutex);
7179 case MODULE_STATE_GOING:
7180 mutex_lock(&btf_module_mutex);
7181 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7182 if (btf_mod->module != module)
7185 list_del(&btf_mod->list);
7186 if (btf_mod->sysfs_attr)
7187 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
7188 purge_cand_cache(btf_mod->btf);
7189 btf_put(btf_mod->btf);
7190 kfree(btf_mod->sysfs_attr);
7194 mutex_unlock(&btf_module_mutex);
7198 return notifier_from_errno(err);
7201 static struct notifier_block btf_module_nb = {
7202 .notifier_call = btf_module_notify,
7205 static int __init btf_module_init(void)
7207 register_module_notifier(&btf_module_nb);
7211 fs_initcall(btf_module_init);
7212 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
7214 struct module *btf_try_get_module(const struct btf *btf)
7216 struct module *res = NULL;
7217 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7218 struct btf_module *btf_mod, *tmp;
7220 mutex_lock(&btf_module_mutex);
7221 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7222 if (btf_mod->btf != btf)
7225 /* We must only consider module whose __init routine has
7226 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
7227 * which is set from the notifier callback for
7228 * MODULE_STATE_LIVE.
7230 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
7231 res = btf_mod->module;
7235 mutex_unlock(&btf_module_mutex);
7241 /* Returns struct btf corresponding to the struct module.
7242 * This function can return NULL or ERR_PTR.
7244 static struct btf *btf_get_module_btf(const struct module *module)
7246 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7247 struct btf_module *btf_mod, *tmp;
7249 struct btf *btf = NULL;
7252 btf = bpf_get_btf_vmlinux();
7253 if (!IS_ERR_OR_NULL(btf))
7258 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7259 mutex_lock(&btf_module_mutex);
7260 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
7261 if (btf_mod->module != module)
7264 btf_get(btf_mod->btf);
7268 mutex_unlock(&btf_module_mutex);
7274 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
7276 struct btf *btf = NULL;
7283 if (name_sz <= 1 || name[name_sz - 1])
7286 ret = bpf_find_btf_id(name, kind, &btf);
7287 if (ret > 0 && btf_is_module(btf)) {
7288 btf_obj_fd = __btf_new_fd(btf);
7289 if (btf_obj_fd < 0) {
7293 return ret | (((u64)btf_obj_fd) << 32);
7300 const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
7301 .func = bpf_btf_find_by_name_kind,
7303 .ret_type = RET_INTEGER,
7304 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
7305 .arg2_type = ARG_CONST_SIZE,
7306 .arg3_type = ARG_ANYTHING,
7307 .arg4_type = ARG_ANYTHING,
7310 BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
7311 #define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
7312 BTF_TRACING_TYPE_xxx
7313 #undef BTF_TRACING_TYPE
7315 /* Kernel Function (kfunc) BTF ID set registration API */
7317 static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
7318 struct btf_id_set8 *add_set)
7320 bool vmlinux_set = !btf_is_module(btf);
7321 struct btf_kfunc_set_tab *tab;
7322 struct btf_id_set8 *set;
7326 if (hook >= BTF_KFUNC_HOOK_MAX) {
7334 tab = btf->kfunc_set_tab;
7336 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
7339 btf->kfunc_set_tab = tab;
7342 set = tab->sets[hook];
7343 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
7346 if (WARN_ON_ONCE(set && !vmlinux_set)) {
7351 /* We don't need to allocate, concatenate, and sort module sets, because
7352 * only one is allowed per hook. Hence, we can directly assign the
7353 * pointer and return.
7356 tab->sets[hook] = add_set;
7360 /* In case of vmlinux sets, there may be more than one set being
7361 * registered per hook. To create a unified set, we allocate a new set
7362 * and concatenate all individual sets being registered. While each set
7363 * is individually sorted, they may become unsorted when concatenated,
7364 * hence re-sorting the final set again is required to make binary
7365 * searching the set using btf_id_set8_contains function work.
7367 set_cnt = set ? set->cnt : 0;
7369 if (set_cnt > U32_MAX - add_set->cnt) {
7374 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
7380 set = krealloc(tab->sets[hook],
7381 offsetof(struct btf_id_set8, pairs[set_cnt + add_set->cnt]),
7382 GFP_KERNEL | __GFP_NOWARN);
7388 /* For newly allocated set, initialize set->cnt to 0 */
7389 if (!tab->sets[hook])
7391 tab->sets[hook] = set;
7393 /* Concatenate the two sets */
7394 memcpy(set->pairs + set->cnt, add_set->pairs, add_set->cnt * sizeof(set->pairs[0]));
7395 set->cnt += add_set->cnt;
7397 sort(set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func, NULL);
7401 btf_free_kfunc_set_tab(btf);
7405 static u32 *__btf_kfunc_id_set_contains(const struct btf *btf,
7406 enum btf_kfunc_hook hook,
7409 struct btf_id_set8 *set;
7412 if (hook >= BTF_KFUNC_HOOK_MAX)
7414 if (!btf->kfunc_set_tab)
7416 set = btf->kfunc_set_tab->sets[hook];
7419 id = btf_id_set8_contains(set, kfunc_btf_id);
7422 /* The flags for BTF ID are located next to it */
7426 static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
7428 switch (prog_type) {
7429 case BPF_PROG_TYPE_XDP:
7430 return BTF_KFUNC_HOOK_XDP;
7431 case BPF_PROG_TYPE_SCHED_CLS:
7432 return BTF_KFUNC_HOOK_TC;
7433 case BPF_PROG_TYPE_STRUCT_OPS:
7434 return BTF_KFUNC_HOOK_STRUCT_OPS;
7435 case BPF_PROG_TYPE_TRACING:
7436 case BPF_PROG_TYPE_LSM:
7437 return BTF_KFUNC_HOOK_TRACING;
7438 case BPF_PROG_TYPE_SYSCALL:
7439 return BTF_KFUNC_HOOK_SYSCALL;
7441 return BTF_KFUNC_HOOK_MAX;
7446 * Reference to the module (obtained using btf_try_get_module) corresponding to
7447 * the struct btf *MUST* be held when calling this function from verifier
7448 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
7449 * keeping the reference for the duration of the call provides the necessary
7450 * protection for looking up a well-formed btf->kfunc_set_tab.
7452 u32 *btf_kfunc_id_set_contains(const struct btf *btf,
7453 enum bpf_prog_type prog_type,
7456 enum btf_kfunc_hook hook;
7458 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7459 return __btf_kfunc_id_set_contains(btf, hook, kfunc_btf_id);
7462 /* This function must be invoked only from initcalls/module init functions */
7463 int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
7464 const struct btf_kfunc_id_set *kset)
7466 enum btf_kfunc_hook hook;
7470 btf = btf_get_module_btf(kset->owner);
7472 if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7473 pr_err("missing vmlinux BTF, cannot register kfuncs\n");
7476 if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7477 pr_err("missing module BTF, cannot register kfuncs\n");
7483 return PTR_ERR(btf);
7485 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7486 ret = btf_populate_kfunc_set(btf, hook, kset->set);
7490 EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
7492 s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id)
7494 struct btf_id_dtor_kfunc_tab *tab = btf->dtor_kfunc_tab;
7495 struct btf_id_dtor_kfunc *dtor;
7499 /* Even though the size of tab->dtors[0] is > sizeof(u32), we only need
7500 * to compare the first u32 with btf_id, so we can reuse btf_id_cmp_func.
7502 BUILD_BUG_ON(offsetof(struct btf_id_dtor_kfunc, btf_id) != 0);
7503 dtor = bsearch(&btf_id, tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func);
7506 return dtor->kfunc_btf_id;
7509 static int btf_check_dtor_kfuncs(struct btf *btf, const struct btf_id_dtor_kfunc *dtors, u32 cnt)
7511 const struct btf_type *dtor_func, *dtor_func_proto, *t;
7512 const struct btf_param *args;
7516 for (i = 0; i < cnt; i++) {
7517 dtor_btf_id = dtors[i].kfunc_btf_id;
7519 dtor_func = btf_type_by_id(btf, dtor_btf_id);
7520 if (!dtor_func || !btf_type_is_func(dtor_func))
7523 dtor_func_proto = btf_type_by_id(btf, dtor_func->type);
7524 if (!dtor_func_proto || !btf_type_is_func_proto(dtor_func_proto))
7527 /* Make sure the prototype of the destructor kfunc is 'void func(type *)' */
7528 t = btf_type_by_id(btf, dtor_func_proto->type);
7529 if (!t || !btf_type_is_void(t))
7532 nr_args = btf_type_vlen(dtor_func_proto);
7535 args = btf_params(dtor_func_proto);
7536 t = btf_type_by_id(btf, args[0].type);
7537 /* Allow any pointer type, as width on targets Linux supports
7538 * will be same for all pointer types (i.e. sizeof(void *))
7540 if (!t || !btf_type_is_ptr(t))
7546 /* This function must be invoked only from initcalls/module init functions */
7547 int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
7548 struct module *owner)
7550 struct btf_id_dtor_kfunc_tab *tab;
7555 btf = btf_get_module_btf(owner);
7557 if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7558 pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n");
7561 if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7562 pr_err("missing module BTF, cannot register dtor kfuncs\n");
7568 return PTR_ERR(btf);
7570 if (add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
7571 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
7576 /* Ensure that the prototype of dtor kfuncs being registered is sane */
7577 ret = btf_check_dtor_kfuncs(btf, dtors, add_cnt);
7581 tab = btf->dtor_kfunc_tab;
7582 /* Only one call allowed for modules */
7583 if (WARN_ON_ONCE(tab && btf_is_module(btf))) {
7588 tab_cnt = tab ? tab->cnt : 0;
7589 if (tab_cnt > U32_MAX - add_cnt) {
7593 if (tab_cnt + add_cnt >= BTF_DTOR_KFUNC_MAX_CNT) {
7594 pr_err("cannot register more than %d kfunc destructors\n", BTF_DTOR_KFUNC_MAX_CNT);
7599 tab = krealloc(btf->dtor_kfunc_tab,
7600 offsetof(struct btf_id_dtor_kfunc_tab, dtors[tab_cnt + add_cnt]),
7601 GFP_KERNEL | __GFP_NOWARN);
7607 if (!btf->dtor_kfunc_tab)
7609 btf->dtor_kfunc_tab = tab;
7611 memcpy(tab->dtors + tab->cnt, dtors, add_cnt * sizeof(tab->dtors[0]));
7612 tab->cnt += add_cnt;
7614 sort(tab->dtors, tab->cnt, sizeof(tab->dtors[0]), btf_id_cmp_func, NULL);
7618 btf_free_dtor_kfunc_tab(btf);
7622 EXPORT_SYMBOL_GPL(register_btf_id_dtor_kfuncs);
7624 #define MAX_TYPES_ARE_COMPAT_DEPTH 2
7626 /* Check local and target types for compatibility. This check is used for
7627 * type-based CO-RE relocations and follow slightly different rules than
7628 * field-based relocations. This function assumes that root types were already
7629 * checked for name match. Beyond that initial root-level name check, names
7630 * are completely ignored. Compatibility rules are as follows:
7631 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but
7632 * kind should match for local and target types (i.e., STRUCT is not
7633 * compatible with UNION);
7634 * - for ENUMs/ENUM64s, the size is ignored;
7635 * - for INT, size and signedness are ignored;
7636 * - for ARRAY, dimensionality is ignored, element types are checked for
7637 * compatibility recursively;
7638 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
7639 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
7640 * - FUNC_PROTOs are compatible if they have compatible signature: same
7641 * number of input args and compatible return and argument types.
7642 * These rules are not set in stone and probably will be adjusted as we get
7643 * more experience with using BPF CO-RE relocations.
7645 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
7646 const struct btf *targ_btf, __u32 targ_id)
7648 return __bpf_core_types_are_compat(local_btf, local_id, targ_btf, targ_id,
7649 MAX_TYPES_ARE_COMPAT_DEPTH);
7652 #define MAX_TYPES_MATCH_DEPTH 2
7654 int bpf_core_types_match(const struct btf *local_btf, u32 local_id,
7655 const struct btf *targ_btf, u32 targ_id)
7657 return __bpf_core_types_match(local_btf, local_id, targ_btf, targ_id, false,
7658 MAX_TYPES_MATCH_DEPTH);
7661 static bool bpf_core_is_flavor_sep(const char *s)
7663 /* check X___Y name pattern, where X and Y are not underscores */
7664 return s[0] != '_' && /* X */
7665 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
7666 s[4] != '_'; /* Y */
7669 size_t bpf_core_essential_name_len(const char *name)
7671 size_t n = strlen(name);
7674 for (i = n - 5; i >= 0; i--) {
7675 if (bpf_core_is_flavor_sep(name + i))
7681 struct bpf_cand_cache {
7687 const struct btf *btf;
7692 static void bpf_free_cands(struct bpf_cand_cache *cands)
7695 /* empty candidate array was allocated on stack */
7700 static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
7706 #define VMLINUX_CAND_CACHE_SIZE 31
7707 static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
7709 #define MODULE_CAND_CACHE_SIZE 31
7710 static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
7712 static DEFINE_MUTEX(cand_cache_mutex);
7714 static void __print_cand_cache(struct bpf_verifier_log *log,
7715 struct bpf_cand_cache **cache,
7718 struct bpf_cand_cache *cc;
7721 for (i = 0; i < cache_size; i++) {
7725 bpf_log(log, "[%d]%s(", i, cc->name);
7726 for (j = 0; j < cc->cnt; j++) {
7727 bpf_log(log, "%d", cc->cands[j].id);
7728 if (j < cc->cnt - 1)
7731 bpf_log(log, "), ");
7735 static void print_cand_cache(struct bpf_verifier_log *log)
7737 mutex_lock(&cand_cache_mutex);
7738 bpf_log(log, "vmlinux_cand_cache:");
7739 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7740 bpf_log(log, "\nmodule_cand_cache:");
7741 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7743 mutex_unlock(&cand_cache_mutex);
7746 static u32 hash_cands(struct bpf_cand_cache *cands)
7748 return jhash(cands->name, cands->name_len, 0);
7751 static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
7752 struct bpf_cand_cache **cache,
7755 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
7757 if (cc && cc->name_len == cands->name_len &&
7758 !strncmp(cc->name, cands->name, cands->name_len))
7763 static size_t sizeof_cands(int cnt)
7765 return offsetof(struct bpf_cand_cache, cands[cnt]);
7768 static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
7769 struct bpf_cand_cache **cache,
7772 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
7775 bpf_free_cands_from_cache(*cc);
7778 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
7780 bpf_free_cands(cands);
7781 return ERR_PTR(-ENOMEM);
7783 /* strdup the name, since it will stay in cache.
7784 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
7786 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
7787 bpf_free_cands(cands);
7788 if (!new_cands->name) {
7790 return ERR_PTR(-ENOMEM);
7796 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7797 static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
7800 struct bpf_cand_cache *cc;
7803 for (i = 0; i < cache_size; i++) {
7808 /* when new module is loaded purge all of module_cand_cache,
7809 * since new module might have candidates with the name
7810 * that matches cached cands.
7812 bpf_free_cands_from_cache(cc);
7816 /* when module is unloaded purge cache entries
7817 * that match module's btf
7819 for (j = 0; j < cc->cnt; j++)
7820 if (cc->cands[j].btf == btf) {
7821 bpf_free_cands_from_cache(cc);
7829 static void purge_cand_cache(struct btf *btf)
7831 mutex_lock(&cand_cache_mutex);
7832 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7833 mutex_unlock(&cand_cache_mutex);
7837 static struct bpf_cand_cache *
7838 bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
7841 struct bpf_cand_cache *new_cands;
7842 const struct btf_type *t;
7843 const char *targ_name;
7844 size_t targ_essent_len;
7847 n = btf_nr_types(targ_btf);
7848 for (i = targ_start_id; i < n; i++) {
7849 t = btf_type_by_id(targ_btf, i);
7850 if (btf_kind(t) != cands->kind)
7853 targ_name = btf_name_by_offset(targ_btf, t->name_off);
7857 /* the resched point is before strncmp to make sure that search
7858 * for non-existing name will have a chance to schedule().
7862 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
7865 targ_essent_len = bpf_core_essential_name_len(targ_name);
7866 if (targ_essent_len != cands->name_len)
7869 /* most of the time there is only one candidate for a given kind+name pair */
7870 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
7872 bpf_free_cands(cands);
7873 return ERR_PTR(-ENOMEM);
7876 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
7877 bpf_free_cands(cands);
7879 cands->cands[cands->cnt].btf = targ_btf;
7880 cands->cands[cands->cnt].id = i;
7886 static struct bpf_cand_cache *
7887 bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
7889 struct bpf_cand_cache *cands, *cc, local_cand = {};
7890 const struct btf *local_btf = ctx->btf;
7891 const struct btf_type *local_type;
7892 const struct btf *main_btf;
7893 size_t local_essent_len;
7894 struct btf *mod_btf;
7898 main_btf = bpf_get_btf_vmlinux();
7899 if (IS_ERR(main_btf))
7900 return ERR_CAST(main_btf);
7902 return ERR_PTR(-EINVAL);
7904 local_type = btf_type_by_id(local_btf, local_type_id);
7906 return ERR_PTR(-EINVAL);
7908 name = btf_name_by_offset(local_btf, local_type->name_off);
7909 if (str_is_empty(name))
7910 return ERR_PTR(-EINVAL);
7911 local_essent_len = bpf_core_essential_name_len(name);
7913 cands = &local_cand;
7915 cands->kind = btf_kind(local_type);
7916 cands->name_len = local_essent_len;
7918 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7919 /* cands is a pointer to stack here */
7926 /* Attempt to find target candidates in vmlinux BTF first */
7927 cands = bpf_core_add_cands(cands, main_btf, 1);
7929 return ERR_CAST(cands);
7931 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
7933 /* populate cache even when cands->cnt == 0 */
7934 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7936 return ERR_CAST(cc);
7938 /* if vmlinux BTF has any candidate, don't go for module BTFs */
7943 /* cands is a pointer to stack here and cands->cnt == 0 */
7944 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7946 /* if cache has it return it even if cc->cnt == 0 */
7949 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
7950 spin_lock_bh(&btf_idr_lock);
7951 idr_for_each_entry(&btf_idr, mod_btf, id) {
7952 if (!btf_is_module(mod_btf))
7954 /* linear search could be slow hence unlock/lock
7955 * the IDR to avoiding holding it for too long
7958 spin_unlock_bh(&btf_idr_lock);
7959 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
7962 return ERR_CAST(cands);
7963 spin_lock_bh(&btf_idr_lock);
7965 spin_unlock_bh(&btf_idr_lock);
7966 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
7967 * or pointer to stack if cands->cnd == 0.
7968 * Copy it into the cache even when cands->cnt == 0 and
7969 * return the result.
7971 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7974 int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
7975 int relo_idx, void *insn)
7977 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
7978 struct bpf_core_cand_list cands = {};
7979 struct bpf_core_relo_res targ_res;
7980 struct bpf_core_spec *specs;
7983 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
7984 * into arrays of btf_ids of struct fields and array indices.
7986 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
7991 struct bpf_cand_cache *cc;
7994 mutex_lock(&cand_cache_mutex);
7995 cc = bpf_core_find_cands(ctx, relo->type_id);
7997 bpf_log(ctx->log, "target candidate search failed for %d\n",
8003 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
8009 for (i = 0; i < cc->cnt; i++) {
8011 "CO-RE relocating %s %s: found target candidate [%d]\n",
8012 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
8013 cands.cands[i].btf = cc->cands[i].btf;
8014 cands.cands[i].id = cc->cands[i].id;
8016 cands.len = cc->cnt;
8017 /* cand_cache_mutex needs to span the cache lookup and
8018 * copy of btf pointer into bpf_core_cand_list,
8019 * since module can be unloaded while bpf_core_calc_relo_insn
8020 * is working with module's btf.
8024 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
8029 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
8036 mutex_unlock(&cand_cache_mutex);
8037 if (ctx->log->level & BPF_LOG_LEVEL2)
8038 print_cand_cache(ctx->log);