1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (c) 2018 Facebook */
4 #include <uapi/linux/btf.h>
5 #include <uapi/linux/types.h>
6 #include <linux/seq_file.h>
7 #include <linux/compiler.h>
8 #include <linux/ctype.h>
9 #include <linux/errno.h>
10 #include <linux/slab.h>
11 #include <linux/anon_inodes.h>
12 #include <linux/file.h>
13 #include <linux/uaccess.h>
14 #include <linux/kernel.h>
15 #include <linux/idr.h>
16 #include <linux/sort.h>
17 #include <linux/bpf_verifier.h>
18 #include <linux/btf.h>
20 /* BTF (BPF Type Format) is the meta data format which describes
21 * the data types of BPF program/map. Hence, it basically focus
22 * on the C programming language which the modern BPF is primary
27 * The BTF data is stored under the ".BTF" ELF section
31 * Each 'struct btf_type' object describes a C data type.
32 * Depending on the type it is describing, a 'struct btf_type'
33 * object may be followed by more data. F.e.
34 * To describe an array, 'struct btf_type' is followed by
37 * 'struct btf_type' and any extra data following it are
42 * The BTF type section contains a list of 'struct btf_type' objects.
43 * Each one describes a C type. Recall from the above section
44 * that a 'struct btf_type' object could be immediately followed by extra
45 * data in order to desribe some particular C types.
49 * Each btf_type object is identified by a type_id. The type_id
50 * is implicitly implied by the location of the btf_type object in
51 * the BTF type section. The first one has type_id 1. The second
52 * one has type_id 2...etc. Hence, an earlier btf_type has
55 * A btf_type object may refer to another btf_type object by using
56 * type_id (i.e. the "type" in the "struct btf_type").
58 * NOTE that we cannot assume any reference-order.
59 * A btf_type object can refer to an earlier btf_type object
60 * but it can also refer to a later btf_type object.
62 * For example, to describe "const void *". A btf_type
63 * object describing "const" may refer to another btf_type
64 * object describing "void *". This type-reference is done
65 * by specifying type_id:
67 * [1] CONST (anon) type_id=2
68 * [2] PTR (anon) type_id=0
70 * The above is the btf_verifier debug log:
71 * - Each line started with "[?]" is a btf_type object
72 * - [?] is the type_id of the btf_type object.
73 * - CONST/PTR is the BTF_KIND_XXX
74 * - "(anon)" is the name of the type. It just
75 * happens that CONST and PTR has no name.
76 * - type_id=XXX is the 'u32 type' in btf_type
78 * NOTE: "void" has type_id 0
82 * The BTF string section contains the names used by the type section.
83 * Each string is referred by an "offset" from the beginning of the
86 * Each string is '\0' terminated.
88 * The first character in the string section must be '\0'
89 * which is used to mean 'anonymous'. Some btf_type may not
95 * To verify BTF data, two passes are needed.
99 * The first pass is to collect all btf_type objects to
100 * an array: "btf->types".
102 * Depending on the C type that a btf_type is describing,
103 * a btf_type may be followed by extra data. We don't know
104 * how many btf_type is there, and more importantly we don't
105 * know where each btf_type is located in the type section.
107 * Without knowing the location of each type_id, most verifications
108 * cannot be done. e.g. an earlier btf_type may refer to a later
109 * btf_type (recall the "const void *" above), so we cannot
110 * check this type-reference in the first pass.
112 * In the first pass, it still does some verifications (e.g.
113 * checking the name is a valid offset to the string section).
117 * The main focus is to resolve a btf_type that is referring
120 * We have to ensure the referring type:
121 * 1) does exist in the BTF (i.e. in btf->types[])
122 * 2) does not cause a loop:
131 * btf_type_needs_resolve() decides if a btf_type needs
134 * The needs_resolve type implements the "resolve()" ops which
135 * essentially does a DFS and detects backedge.
137 * During resolve (or DFS), different C types have different
138 * "RESOLVED" conditions.
140 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
141 * members because a member is always referring to another
142 * type. A struct's member can be treated as "RESOLVED" if
143 * it is referring to a BTF_KIND_PTR. Otherwise, the
144 * following valid C struct would be rejected:
151 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
152 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
153 * detect a pointer loop, e.g.:
154 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
156 * +-----------------------------------------+
160 #define BITS_PER_U64 (sizeof(u64) * BITS_PER_BYTE)
161 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
162 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
163 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
164 #define BITS_ROUNDUP_BYTES(bits) \
165 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
167 #define BTF_INFO_MASK 0x8f00ffff
168 #define BTF_INT_MASK 0x0fffffff
169 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
170 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
172 /* 16MB for 64k structs and each has 16 members and
173 * a few MB spaces for the string section.
174 * The hard limit is S32_MAX.
176 #define BTF_MAX_SIZE (16 * 1024 * 1024)
178 #define for_each_member(i, struct_type, member) \
179 for (i = 0, member = btf_type_member(struct_type); \
180 i < btf_type_vlen(struct_type); \
183 #define for_each_member_from(i, from, struct_type, member) \
184 for (i = from, member = btf_type_member(struct_type) + from; \
185 i < btf_type_vlen(struct_type); \
188 static DEFINE_IDR(btf_idr);
189 static DEFINE_SPINLOCK(btf_idr_lock);
193 struct btf_type **types;
198 struct btf_header hdr;
207 enum verifier_phase {
212 struct resolve_vertex {
213 const struct btf_type *t;
225 RESOLVE_TBD, /* To Be Determined */
226 RESOLVE_PTR, /* Resolving for Pointer */
227 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
232 #define MAX_RESOLVE_DEPTH 32
234 struct btf_sec_info {
239 struct btf_verifier_env {
242 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
243 struct bpf_verifier_log log;
246 enum verifier_phase phase;
247 enum resolve_mode resolve_mode;
250 static const char * const btf_kind_str[NR_BTF_KINDS] = {
251 [BTF_KIND_UNKN] = "UNKNOWN",
252 [BTF_KIND_INT] = "INT",
253 [BTF_KIND_PTR] = "PTR",
254 [BTF_KIND_ARRAY] = "ARRAY",
255 [BTF_KIND_STRUCT] = "STRUCT",
256 [BTF_KIND_UNION] = "UNION",
257 [BTF_KIND_ENUM] = "ENUM",
258 [BTF_KIND_FWD] = "FWD",
259 [BTF_KIND_TYPEDEF] = "TYPEDEF",
260 [BTF_KIND_VOLATILE] = "VOLATILE",
261 [BTF_KIND_CONST] = "CONST",
262 [BTF_KIND_RESTRICT] = "RESTRICT",
263 [BTF_KIND_FUNC] = "FUNC",
264 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
267 struct btf_kind_operations {
268 s32 (*check_meta)(struct btf_verifier_env *env,
269 const struct btf_type *t,
271 int (*resolve)(struct btf_verifier_env *env,
272 const struct resolve_vertex *v);
273 int (*check_member)(struct btf_verifier_env *env,
274 const struct btf_type *struct_type,
275 const struct btf_member *member,
276 const struct btf_type *member_type);
277 int (*check_kflag_member)(struct btf_verifier_env *env,
278 const struct btf_type *struct_type,
279 const struct btf_member *member,
280 const struct btf_type *member_type);
281 void (*log_details)(struct btf_verifier_env *env,
282 const struct btf_type *t);
283 void (*seq_show)(const struct btf *btf, const struct btf_type *t,
284 u32 type_id, void *data, u8 bits_offsets,
288 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
289 static struct btf_type btf_void;
291 static int btf_resolve(struct btf_verifier_env *env,
292 const struct btf_type *t, u32 type_id);
294 static bool btf_type_is_modifier(const struct btf_type *t)
296 /* Some of them is not strictly a C modifier
297 * but they are grouped into the same bucket
299 * A type (t) that refers to another
300 * type through t->type AND its size cannot
301 * be determined without following the t->type.
303 * ptr does not fall into this bucket
304 * because its size is always sizeof(void *).
306 switch (BTF_INFO_KIND(t->info)) {
307 case BTF_KIND_TYPEDEF:
308 case BTF_KIND_VOLATILE:
310 case BTF_KIND_RESTRICT:
317 static bool btf_type_is_void(const struct btf_type *t)
319 return t == &btf_void;
322 static bool btf_type_is_fwd(const struct btf_type *t)
324 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
327 static bool btf_type_is_func(const struct btf_type *t)
329 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC;
332 static bool btf_type_is_func_proto(const struct btf_type *t)
334 return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO;
337 static bool btf_type_nosize(const struct btf_type *t)
339 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
340 btf_type_is_func(t) || btf_type_is_func_proto(t);
343 static bool btf_type_nosize_or_null(const struct btf_type *t)
345 return !t || btf_type_nosize(t);
348 /* union is only a special case of struct:
349 * all its offsetof(member) == 0
351 static bool btf_type_is_struct(const struct btf_type *t)
353 u8 kind = BTF_INFO_KIND(t->info);
355 return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
358 static bool btf_type_is_array(const struct btf_type *t)
360 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
363 static bool btf_type_is_ptr(const struct btf_type *t)
365 return BTF_INFO_KIND(t->info) == BTF_KIND_PTR;
368 static bool btf_type_is_int(const struct btf_type *t)
370 return BTF_INFO_KIND(t->info) == BTF_KIND_INT;
373 /* What types need to be resolved?
375 * btf_type_is_modifier() is an obvious one.
377 * btf_type_is_struct() because its member refers to
378 * another type (through member->type).
380 * btf_type_is_array() because its element (array->type)
381 * refers to another type. Array can be thought of a
382 * special case of struct while array just has the same
383 * member-type repeated by array->nelems of times.
385 static bool btf_type_needs_resolve(const struct btf_type *t)
387 return btf_type_is_modifier(t) ||
388 btf_type_is_ptr(t) ||
389 btf_type_is_struct(t) ||
390 btf_type_is_array(t);
393 /* t->size can be used */
394 static bool btf_type_has_size(const struct btf_type *t)
396 switch (BTF_INFO_KIND(t->info)) {
398 case BTF_KIND_STRUCT:
407 static const char *btf_int_encoding_str(u8 encoding)
411 else if (encoding == BTF_INT_SIGNED)
413 else if (encoding == BTF_INT_CHAR)
415 else if (encoding == BTF_INT_BOOL)
421 static u16 btf_type_vlen(const struct btf_type *t)
423 return BTF_INFO_VLEN(t->info);
426 static bool btf_type_kflag(const struct btf_type *t)
428 return BTF_INFO_KFLAG(t->info);
431 static u32 btf_member_bit_offset(const struct btf_type *struct_type,
432 const struct btf_member *member)
434 return btf_type_kflag(struct_type) ? BTF_MEMBER_BIT_OFFSET(member->offset)
438 static u32 btf_member_bitfield_size(const struct btf_type *struct_type,
439 const struct btf_member *member)
441 return btf_type_kflag(struct_type) ? BTF_MEMBER_BITFIELD_SIZE(member->offset)
445 static u32 btf_type_int(const struct btf_type *t)
447 return *(u32 *)(t + 1);
450 static const struct btf_array *btf_type_array(const struct btf_type *t)
452 return (const struct btf_array *)(t + 1);
455 static const struct btf_member *btf_type_member(const struct btf_type *t)
457 return (const struct btf_member *)(t + 1);
460 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
462 return (const struct btf_enum *)(t + 1);
465 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
467 return kind_ops[BTF_INFO_KIND(t->info)];
470 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
472 return BTF_STR_OFFSET_VALID(offset) &&
473 offset < btf->hdr.str_len;
476 /* Only C-style identifier is permitted. This can be relaxed if
479 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
481 /* offset must be valid */
482 const char *src = &btf->strings[offset];
483 const char *src_limit;
485 if (!isalpha(*src) && *src != '_')
488 /* set a limit on identifier length */
489 src_limit = src + KSYM_NAME_LEN;
491 while (*src && src < src_limit) {
492 if (!isalnum(*src) && *src != '_')
500 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
504 else if (offset < btf->hdr.str_len)
505 return &btf->strings[offset];
507 return "(invalid-name-offset)";
510 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
512 if (offset < btf->hdr.str_len)
513 return &btf->strings[offset];
518 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
520 if (type_id > btf->nr_types)
523 return btf->types[type_id];
527 * Regular int is not a bit field and it must be either
530 static bool btf_type_int_is_regular(const struct btf_type *t)
532 u8 nr_bits, nr_bytes;
535 int_data = btf_type_int(t);
536 nr_bits = BTF_INT_BITS(int_data);
537 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
538 if (BITS_PER_BYTE_MASKED(nr_bits) ||
539 BTF_INT_OFFSET(int_data) ||
540 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
541 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64))) {
549 * Check that given struct member is a regular int with expected
552 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
553 const struct btf_member *m,
554 u32 expected_offset, u32 expected_size)
556 const struct btf_type *t;
561 t = btf_type_id_size(btf, &id, NULL);
562 if (!t || !btf_type_is_int(t))
565 int_data = btf_type_int(t);
566 nr_bits = BTF_INT_BITS(int_data);
567 if (btf_type_kflag(s)) {
568 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
569 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
571 /* if kflag set, int should be a regular int and
572 * bit offset should be at byte boundary.
574 return !bitfield_size &&
575 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
576 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
579 if (BTF_INT_OFFSET(int_data) ||
580 BITS_PER_BYTE_MASKED(m->offset) ||
581 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
582 BITS_PER_BYTE_MASKED(nr_bits) ||
583 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
589 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
590 const char *fmt, ...)
595 bpf_verifier_vlog(log, fmt, args);
599 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
600 const char *fmt, ...)
602 struct bpf_verifier_log *log = &env->log;
605 if (!bpf_verifier_log_needed(log))
609 bpf_verifier_vlog(log, fmt, args);
613 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
614 const struct btf_type *t,
616 const char *fmt, ...)
618 struct bpf_verifier_log *log = &env->log;
619 u8 kind = BTF_INFO_KIND(t->info);
620 struct btf *btf = env->btf;
623 if (!bpf_verifier_log_needed(log))
626 __btf_verifier_log(log, "[%u] %s %s%s",
629 __btf_name_by_offset(btf, t->name_off),
630 log_details ? " " : "");
633 btf_type_ops(t)->log_details(env, t);
636 __btf_verifier_log(log, " ");
638 bpf_verifier_vlog(log, fmt, args);
642 __btf_verifier_log(log, "\n");
645 #define btf_verifier_log_type(env, t, ...) \
646 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
647 #define btf_verifier_log_basic(env, t, ...) \
648 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
651 static void btf_verifier_log_member(struct btf_verifier_env *env,
652 const struct btf_type *struct_type,
653 const struct btf_member *member,
654 const char *fmt, ...)
656 struct bpf_verifier_log *log = &env->log;
657 struct btf *btf = env->btf;
660 if (!bpf_verifier_log_needed(log))
663 /* The CHECK_META phase already did a btf dump.
665 * If member is logged again, it must hit an error in
666 * parsing this member. It is useful to print out which
667 * struct this member belongs to.
669 if (env->phase != CHECK_META)
670 btf_verifier_log_type(env, struct_type, NULL);
672 if (btf_type_kflag(struct_type))
673 __btf_verifier_log(log,
674 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
675 __btf_name_by_offset(btf, member->name_off),
677 BTF_MEMBER_BITFIELD_SIZE(member->offset),
678 BTF_MEMBER_BIT_OFFSET(member->offset));
680 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
681 __btf_name_by_offset(btf, member->name_off),
682 member->type, member->offset);
685 __btf_verifier_log(log, " ");
687 bpf_verifier_vlog(log, fmt, args);
691 __btf_verifier_log(log, "\n");
694 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
697 struct bpf_verifier_log *log = &env->log;
698 const struct btf *btf = env->btf;
699 const struct btf_header *hdr;
701 if (!bpf_verifier_log_needed(log))
705 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
706 __btf_verifier_log(log, "version: %u\n", hdr->version);
707 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
708 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
709 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
710 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
711 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
712 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
713 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
716 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
718 struct btf *btf = env->btf;
720 /* < 2 because +1 for btf_void which is always in btf->types[0].
721 * btf_void is not accounted in btf->nr_types because btf_void
722 * does not come from the BTF file.
724 if (btf->types_size - btf->nr_types < 2) {
725 /* Expand 'types' array */
727 struct btf_type **new_types;
728 u32 expand_by, new_size;
730 if (btf->types_size == BTF_MAX_TYPE) {
731 btf_verifier_log(env, "Exceeded max num of types");
735 expand_by = max_t(u32, btf->types_size >> 2, 16);
736 new_size = min_t(u32, BTF_MAX_TYPE,
737 btf->types_size + expand_by);
739 new_types = kvcalloc(new_size, sizeof(*new_types),
740 GFP_KERNEL | __GFP_NOWARN);
744 if (btf->nr_types == 0)
745 new_types[0] = &btf_void;
747 memcpy(new_types, btf->types,
748 sizeof(*btf->types) * (btf->nr_types + 1));
751 btf->types = new_types;
752 btf->types_size = new_size;
755 btf->types[++(btf->nr_types)] = t;
760 static int btf_alloc_id(struct btf *btf)
764 idr_preload(GFP_KERNEL);
765 spin_lock_bh(&btf_idr_lock);
766 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
769 spin_unlock_bh(&btf_idr_lock);
772 if (WARN_ON_ONCE(!id))
775 return id > 0 ? 0 : id;
778 static void btf_free_id(struct btf *btf)
783 * In map-in-map, calling map_delete_elem() on outer
784 * map will call bpf_map_put on the inner map.
785 * It will then eventually call btf_free_id()
786 * on the inner map. Some of the map_delete_elem()
787 * implementation may have irq disabled, so
788 * we need to use the _irqsave() version instead
789 * of the _bh() version.
791 spin_lock_irqsave(&btf_idr_lock, flags);
792 idr_remove(&btf_idr, btf->id);
793 spin_unlock_irqrestore(&btf_idr_lock, flags);
796 static void btf_free(struct btf *btf)
799 kvfree(btf->resolved_sizes);
800 kvfree(btf->resolved_ids);
805 static void btf_free_rcu(struct rcu_head *rcu)
807 struct btf *btf = container_of(rcu, struct btf, rcu);
812 void btf_put(struct btf *btf)
814 if (btf && refcount_dec_and_test(&btf->refcnt)) {
816 call_rcu(&btf->rcu, btf_free_rcu);
820 static int env_resolve_init(struct btf_verifier_env *env)
822 struct btf *btf = env->btf;
823 u32 nr_types = btf->nr_types;
824 u32 *resolved_sizes = NULL;
825 u32 *resolved_ids = NULL;
826 u8 *visit_states = NULL;
828 /* +1 for btf_void */
829 resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes),
830 GFP_KERNEL | __GFP_NOWARN);
834 resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids),
835 GFP_KERNEL | __GFP_NOWARN);
839 visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states),
840 GFP_KERNEL | __GFP_NOWARN);
844 btf->resolved_sizes = resolved_sizes;
845 btf->resolved_ids = resolved_ids;
846 env->visit_states = visit_states;
851 kvfree(resolved_sizes);
852 kvfree(resolved_ids);
853 kvfree(visit_states);
857 static void btf_verifier_env_free(struct btf_verifier_env *env)
859 kvfree(env->visit_states);
863 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
864 const struct btf_type *next_type)
866 switch (env->resolve_mode) {
868 /* int, enum or void is a sink */
869 return !btf_type_needs_resolve(next_type);
871 /* int, enum, void, struct, array, func or func_proto is a sink
874 return !btf_type_is_modifier(next_type) &&
875 !btf_type_is_ptr(next_type);
876 case RESOLVE_STRUCT_OR_ARRAY:
877 /* int, enum, void, ptr, func or func_proto is a sink
878 * for struct and array
880 return !btf_type_is_modifier(next_type) &&
881 !btf_type_is_array(next_type) &&
882 !btf_type_is_struct(next_type);
888 static bool env_type_is_resolved(const struct btf_verifier_env *env,
891 return env->visit_states[type_id] == RESOLVED;
894 static int env_stack_push(struct btf_verifier_env *env,
895 const struct btf_type *t, u32 type_id)
897 struct resolve_vertex *v;
899 if (env->top_stack == MAX_RESOLVE_DEPTH)
902 if (env->visit_states[type_id] != NOT_VISITED)
905 env->visit_states[type_id] = VISITED;
907 v = &env->stack[env->top_stack++];
909 v->type_id = type_id;
912 if (env->resolve_mode == RESOLVE_TBD) {
913 if (btf_type_is_ptr(t))
914 env->resolve_mode = RESOLVE_PTR;
915 else if (btf_type_is_struct(t) || btf_type_is_array(t))
916 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
922 static void env_stack_set_next_member(struct btf_verifier_env *env,
925 env->stack[env->top_stack - 1].next_member = next_member;
928 static void env_stack_pop_resolved(struct btf_verifier_env *env,
929 u32 resolved_type_id,
932 u32 type_id = env->stack[--(env->top_stack)].type_id;
933 struct btf *btf = env->btf;
935 btf->resolved_sizes[type_id] = resolved_size;
936 btf->resolved_ids[type_id] = resolved_type_id;
937 env->visit_states[type_id] = RESOLVED;
940 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
942 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
945 /* The input param "type_id" must point to a needs_resolve type */
946 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
949 *type_id = btf->resolved_ids[*type_id];
950 return btf_type_by_id(btf, *type_id);
953 const struct btf_type *btf_type_id_size(const struct btf *btf,
954 u32 *type_id, u32 *ret_size)
956 const struct btf_type *size_type;
957 u32 size_type_id = *type_id;
960 size_type = btf_type_by_id(btf, size_type_id);
961 if (btf_type_nosize_or_null(size_type))
964 if (btf_type_has_size(size_type)) {
965 size = size_type->size;
966 } else if (btf_type_is_array(size_type)) {
967 size = btf->resolved_sizes[size_type_id];
968 } else if (btf_type_is_ptr(size_type)) {
969 size = sizeof(void *);
971 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type)))
974 size = btf->resolved_sizes[size_type_id];
975 size_type_id = btf->resolved_ids[size_type_id];
976 size_type = btf_type_by_id(btf, size_type_id);
977 if (btf_type_nosize_or_null(size_type))
981 *type_id = size_type_id;
988 static int btf_df_check_member(struct btf_verifier_env *env,
989 const struct btf_type *struct_type,
990 const struct btf_member *member,
991 const struct btf_type *member_type)
993 btf_verifier_log_basic(env, struct_type,
994 "Unsupported check_member");
998 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
999 const struct btf_type *struct_type,
1000 const struct btf_member *member,
1001 const struct btf_type *member_type)
1003 btf_verifier_log_basic(env, struct_type,
1004 "Unsupported check_kflag_member");
1008 /* Used for ptr, array and struct/union type members.
1009 * int, enum and modifier types have their specific callback functions.
1011 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1012 const struct btf_type *struct_type,
1013 const struct btf_member *member,
1014 const struct btf_type *member_type)
1016 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1017 btf_verifier_log_member(env, struct_type, member,
1018 "Invalid member bitfield_size");
1022 /* bitfield size is 0, so member->offset represents bit offset only.
1023 * It is safe to call non kflag check_member variants.
1025 return btf_type_ops(member_type)->check_member(env, struct_type,
1030 static int btf_df_resolve(struct btf_verifier_env *env,
1031 const struct resolve_vertex *v)
1033 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1037 static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t,
1038 u32 type_id, void *data, u8 bits_offsets,
1041 seq_printf(m, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1044 static int btf_int_check_member(struct btf_verifier_env *env,
1045 const struct btf_type *struct_type,
1046 const struct btf_member *member,
1047 const struct btf_type *member_type)
1049 u32 int_data = btf_type_int(member_type);
1050 u32 struct_bits_off = member->offset;
1051 u32 struct_size = struct_type->size;
1055 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1056 btf_verifier_log_member(env, struct_type, member,
1057 "bits_offset exceeds U32_MAX");
1061 struct_bits_off += BTF_INT_OFFSET(int_data);
1062 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1063 nr_copy_bits = BTF_INT_BITS(int_data) +
1064 BITS_PER_BYTE_MASKED(struct_bits_off);
1066 if (nr_copy_bits > BITS_PER_U64) {
1067 btf_verifier_log_member(env, struct_type, member,
1068 "nr_copy_bits exceeds 64");
1072 if (struct_size < bytes_offset ||
1073 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1074 btf_verifier_log_member(env, struct_type, member,
1075 "Member exceeds struct_size");
1082 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1083 const struct btf_type *struct_type,
1084 const struct btf_member *member,
1085 const struct btf_type *member_type)
1087 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1088 u32 int_data = btf_type_int(member_type);
1089 u32 struct_size = struct_type->size;
1092 /* a regular int type is required for the kflag int member */
1093 if (!btf_type_int_is_regular(member_type)) {
1094 btf_verifier_log_member(env, struct_type, member,
1095 "Invalid member base type");
1099 /* check sanity of bitfield size */
1100 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
1101 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
1102 nr_int_data_bits = BTF_INT_BITS(int_data);
1104 /* Not a bitfield member, member offset must be at byte
1107 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1108 btf_verifier_log_member(env, struct_type, member,
1109 "Invalid member offset");
1113 nr_bits = nr_int_data_bits;
1114 } else if (nr_bits > nr_int_data_bits) {
1115 btf_verifier_log_member(env, struct_type, member,
1116 "Invalid member bitfield_size");
1120 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1121 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
1122 if (nr_copy_bits > BITS_PER_U64) {
1123 btf_verifier_log_member(env, struct_type, member,
1124 "nr_copy_bits exceeds 64");
1128 if (struct_size < bytes_offset ||
1129 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1130 btf_verifier_log_member(env, struct_type, member,
1131 "Member exceeds struct_size");
1138 static s32 btf_int_check_meta(struct btf_verifier_env *env,
1139 const struct btf_type *t,
1142 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
1145 if (meta_left < meta_needed) {
1146 btf_verifier_log_basic(env, t,
1147 "meta_left:%u meta_needed:%u",
1148 meta_left, meta_needed);
1152 if (btf_type_vlen(t)) {
1153 btf_verifier_log_type(env, t, "vlen != 0");
1157 if (btf_type_kflag(t)) {
1158 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1162 int_data = btf_type_int(t);
1163 if (int_data & ~BTF_INT_MASK) {
1164 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
1169 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
1171 if (nr_bits > BITS_PER_U64) {
1172 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
1177 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
1178 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
1183 * Only one of the encoding bits is allowed and it
1184 * should be sufficient for the pretty print purpose (i.e. decoding).
1185 * Multiple bits can be allowed later if it is found
1186 * to be insufficient.
1188 encoding = BTF_INT_ENCODING(int_data);
1190 encoding != BTF_INT_SIGNED &&
1191 encoding != BTF_INT_CHAR &&
1192 encoding != BTF_INT_BOOL) {
1193 btf_verifier_log_type(env, t, "Unsupported encoding");
1197 btf_verifier_log_type(env, t, NULL);
1202 static void btf_int_log(struct btf_verifier_env *env,
1203 const struct btf_type *t)
1205 int int_data = btf_type_int(t);
1207 btf_verifier_log(env,
1208 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
1209 t->size, BTF_INT_OFFSET(int_data),
1210 BTF_INT_BITS(int_data),
1211 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
1214 static void btf_bitfield_seq_show(void *data, u8 bits_offset,
1215 u8 nr_bits, struct seq_file *m)
1217 u16 left_shift_bits, right_shift_bits;
1222 nr_copy_bits = nr_bits + bits_offset;
1223 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
1226 memcpy(&print_num, data, nr_copy_bytes);
1228 #ifdef __BIG_ENDIAN_BITFIELD
1229 left_shift_bits = bits_offset;
1231 left_shift_bits = BITS_PER_U64 - nr_copy_bits;
1233 right_shift_bits = BITS_PER_U64 - nr_bits;
1235 print_num <<= left_shift_bits;
1236 print_num >>= right_shift_bits;
1238 seq_printf(m, "0x%llx", print_num);
1242 static void btf_int_bits_seq_show(const struct btf *btf,
1243 const struct btf_type *t,
1244 void *data, u8 bits_offset,
1247 u32 int_data = btf_type_int(t);
1248 u8 nr_bits = BTF_INT_BITS(int_data);
1249 u8 total_bits_offset;
1252 * bits_offset is at most 7.
1253 * BTF_INT_OFFSET() cannot exceed 64 bits.
1255 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
1256 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
1257 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
1258 btf_bitfield_seq_show(data, bits_offset, nr_bits, m);
1261 static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t,
1262 u32 type_id, void *data, u8 bits_offset,
1265 u32 int_data = btf_type_int(t);
1266 u8 encoding = BTF_INT_ENCODING(int_data);
1267 bool sign = encoding & BTF_INT_SIGNED;
1268 u8 nr_bits = BTF_INT_BITS(int_data);
1270 if (bits_offset || BTF_INT_OFFSET(int_data) ||
1271 BITS_PER_BYTE_MASKED(nr_bits)) {
1272 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1279 seq_printf(m, "%lld", *(s64 *)data);
1281 seq_printf(m, "%llu", *(u64 *)data);
1285 seq_printf(m, "%d", *(s32 *)data);
1287 seq_printf(m, "%u", *(u32 *)data);
1291 seq_printf(m, "%d", *(s16 *)data);
1293 seq_printf(m, "%u", *(u16 *)data);
1297 seq_printf(m, "%d", *(s8 *)data);
1299 seq_printf(m, "%u", *(u8 *)data);
1302 btf_int_bits_seq_show(btf, t, data, bits_offset, m);
1306 static const struct btf_kind_operations int_ops = {
1307 .check_meta = btf_int_check_meta,
1308 .resolve = btf_df_resolve,
1309 .check_member = btf_int_check_member,
1310 .check_kflag_member = btf_int_check_kflag_member,
1311 .log_details = btf_int_log,
1312 .seq_show = btf_int_seq_show,
1315 static int btf_modifier_check_member(struct btf_verifier_env *env,
1316 const struct btf_type *struct_type,
1317 const struct btf_member *member,
1318 const struct btf_type *member_type)
1320 const struct btf_type *resolved_type;
1321 u32 resolved_type_id = member->type;
1322 struct btf_member resolved_member;
1323 struct btf *btf = env->btf;
1325 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1326 if (!resolved_type) {
1327 btf_verifier_log_member(env, struct_type, member,
1332 resolved_member = *member;
1333 resolved_member.type = resolved_type_id;
1335 return btf_type_ops(resolved_type)->check_member(env, struct_type,
1340 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
1341 const struct btf_type *struct_type,
1342 const struct btf_member *member,
1343 const struct btf_type *member_type)
1345 const struct btf_type *resolved_type;
1346 u32 resolved_type_id = member->type;
1347 struct btf_member resolved_member;
1348 struct btf *btf = env->btf;
1350 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
1351 if (!resolved_type) {
1352 btf_verifier_log_member(env, struct_type, member,
1357 resolved_member = *member;
1358 resolved_member.type = resolved_type_id;
1360 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
1365 static int btf_ptr_check_member(struct btf_verifier_env *env,
1366 const struct btf_type *struct_type,
1367 const struct btf_member *member,
1368 const struct btf_type *member_type)
1370 u32 struct_size, struct_bits_off, bytes_offset;
1372 struct_size = struct_type->size;
1373 struct_bits_off = member->offset;
1374 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1376 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1377 btf_verifier_log_member(env, struct_type, member,
1378 "Member is not byte aligned");
1382 if (struct_size - bytes_offset < sizeof(void *)) {
1383 btf_verifier_log_member(env, struct_type, member,
1384 "Member exceeds struct_size");
1391 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
1392 const struct btf_type *t,
1395 if (btf_type_vlen(t)) {
1396 btf_verifier_log_type(env, t, "vlen != 0");
1400 if (btf_type_kflag(t)) {
1401 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1405 if (!BTF_TYPE_ID_VALID(t->type)) {
1406 btf_verifier_log_type(env, t, "Invalid type_id");
1410 /* typedef type must have a valid name, and other ref types,
1411 * volatile, const, restrict, should have a null name.
1413 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
1415 !btf_name_valid_identifier(env->btf, t->name_off)) {
1416 btf_verifier_log_type(env, t, "Invalid name");
1421 btf_verifier_log_type(env, t, "Invalid name");
1426 btf_verifier_log_type(env, t, NULL);
1431 static int btf_modifier_resolve(struct btf_verifier_env *env,
1432 const struct resolve_vertex *v)
1434 const struct btf_type *t = v->t;
1435 const struct btf_type *next_type;
1436 u32 next_type_id = t->type;
1437 struct btf *btf = env->btf;
1438 u32 next_type_size = 0;
1440 next_type = btf_type_by_id(btf, next_type_id);
1442 btf_verifier_log_type(env, v->t, "Invalid type_id");
1446 if (!env_type_is_resolve_sink(env, next_type) &&
1447 !env_type_is_resolved(env, next_type_id))
1448 return env_stack_push(env, next_type, next_type_id);
1450 /* Figure out the resolved next_type_id with size.
1451 * They will be stored in the current modifier's
1452 * resolved_ids and resolved_sizes such that it can
1453 * save us a few type-following when we use it later (e.g. in
1456 if (!btf_type_id_size(btf, &next_type_id, &next_type_size)) {
1457 if (env_type_is_resolved(env, next_type_id))
1458 next_type = btf_type_id_resolve(btf, &next_type_id);
1460 /* "typedef void new_void", "const void"...etc */
1461 if (!btf_type_is_void(next_type) &&
1462 !btf_type_is_fwd(next_type)) {
1463 btf_verifier_log_type(env, v->t, "Invalid type_id");
1468 env_stack_pop_resolved(env, next_type_id, next_type_size);
1473 static int btf_ptr_resolve(struct btf_verifier_env *env,
1474 const struct resolve_vertex *v)
1476 const struct btf_type *next_type;
1477 const struct btf_type *t = v->t;
1478 u32 next_type_id = t->type;
1479 struct btf *btf = env->btf;
1481 next_type = btf_type_by_id(btf, next_type_id);
1483 btf_verifier_log_type(env, v->t, "Invalid type_id");
1487 if (!env_type_is_resolve_sink(env, next_type) &&
1488 !env_type_is_resolved(env, next_type_id))
1489 return env_stack_push(env, next_type, next_type_id);
1491 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
1492 * the modifier may have stopped resolving when it was resolved
1493 * to a ptr (last-resolved-ptr).
1495 * We now need to continue from the last-resolved-ptr to
1496 * ensure the last-resolved-ptr will not referring back to
1497 * the currenct ptr (t).
1499 if (btf_type_is_modifier(next_type)) {
1500 const struct btf_type *resolved_type;
1501 u32 resolved_type_id;
1503 resolved_type_id = next_type_id;
1504 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
1506 if (btf_type_is_ptr(resolved_type) &&
1507 !env_type_is_resolve_sink(env, resolved_type) &&
1508 !env_type_is_resolved(env, resolved_type_id))
1509 return env_stack_push(env, resolved_type,
1513 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
1514 if (env_type_is_resolved(env, next_type_id))
1515 next_type = btf_type_id_resolve(btf, &next_type_id);
1517 if (!btf_type_is_void(next_type) &&
1518 !btf_type_is_fwd(next_type) &&
1519 !btf_type_is_func_proto(next_type)) {
1520 btf_verifier_log_type(env, v->t, "Invalid type_id");
1525 env_stack_pop_resolved(env, next_type_id, 0);
1530 static void btf_modifier_seq_show(const struct btf *btf,
1531 const struct btf_type *t,
1532 u32 type_id, void *data,
1533 u8 bits_offset, struct seq_file *m)
1535 t = btf_type_id_resolve(btf, &type_id);
1537 btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m);
1540 static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t,
1541 u32 type_id, void *data, u8 bits_offset,
1544 /* It is a hashed value */
1545 seq_printf(m, "%p", *(void **)data);
1548 static void btf_ref_type_log(struct btf_verifier_env *env,
1549 const struct btf_type *t)
1551 btf_verifier_log(env, "type_id=%u", t->type);
1554 static struct btf_kind_operations modifier_ops = {
1555 .check_meta = btf_ref_type_check_meta,
1556 .resolve = btf_modifier_resolve,
1557 .check_member = btf_modifier_check_member,
1558 .check_kflag_member = btf_modifier_check_kflag_member,
1559 .log_details = btf_ref_type_log,
1560 .seq_show = btf_modifier_seq_show,
1563 static struct btf_kind_operations ptr_ops = {
1564 .check_meta = btf_ref_type_check_meta,
1565 .resolve = btf_ptr_resolve,
1566 .check_member = btf_ptr_check_member,
1567 .check_kflag_member = btf_generic_check_kflag_member,
1568 .log_details = btf_ref_type_log,
1569 .seq_show = btf_ptr_seq_show,
1572 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
1573 const struct btf_type *t,
1576 if (btf_type_vlen(t)) {
1577 btf_verifier_log_type(env, t, "vlen != 0");
1582 btf_verifier_log_type(env, t, "type != 0");
1586 /* fwd type must have a valid name */
1588 !btf_name_valid_identifier(env->btf, t->name_off)) {
1589 btf_verifier_log_type(env, t, "Invalid name");
1593 btf_verifier_log_type(env, t, NULL);
1598 static void btf_fwd_type_log(struct btf_verifier_env *env,
1599 const struct btf_type *t)
1601 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
1604 static struct btf_kind_operations fwd_ops = {
1605 .check_meta = btf_fwd_check_meta,
1606 .resolve = btf_df_resolve,
1607 .check_member = btf_df_check_member,
1608 .check_kflag_member = btf_df_check_kflag_member,
1609 .log_details = btf_fwd_type_log,
1610 .seq_show = btf_df_seq_show,
1613 static int btf_array_check_member(struct btf_verifier_env *env,
1614 const struct btf_type *struct_type,
1615 const struct btf_member *member,
1616 const struct btf_type *member_type)
1618 u32 struct_bits_off = member->offset;
1619 u32 struct_size, bytes_offset;
1620 u32 array_type_id, array_size;
1621 struct btf *btf = env->btf;
1623 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1624 btf_verifier_log_member(env, struct_type, member,
1625 "Member is not byte aligned");
1629 array_type_id = member->type;
1630 btf_type_id_size(btf, &array_type_id, &array_size);
1631 struct_size = struct_type->size;
1632 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1633 if (struct_size - bytes_offset < array_size) {
1634 btf_verifier_log_member(env, struct_type, member,
1635 "Member exceeds struct_size");
1642 static s32 btf_array_check_meta(struct btf_verifier_env *env,
1643 const struct btf_type *t,
1646 const struct btf_array *array = btf_type_array(t);
1647 u32 meta_needed = sizeof(*array);
1649 if (meta_left < meta_needed) {
1650 btf_verifier_log_basic(env, t,
1651 "meta_left:%u meta_needed:%u",
1652 meta_left, meta_needed);
1656 /* array type should not have a name */
1658 btf_verifier_log_type(env, t, "Invalid name");
1662 if (btf_type_vlen(t)) {
1663 btf_verifier_log_type(env, t, "vlen != 0");
1667 if (btf_type_kflag(t)) {
1668 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
1673 btf_verifier_log_type(env, t, "size != 0");
1677 /* Array elem type and index type cannot be in type void,
1678 * so !array->type and !array->index_type are not allowed.
1680 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
1681 btf_verifier_log_type(env, t, "Invalid elem");
1685 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
1686 btf_verifier_log_type(env, t, "Invalid index");
1690 btf_verifier_log_type(env, t, NULL);
1695 static int btf_array_resolve(struct btf_verifier_env *env,
1696 const struct resolve_vertex *v)
1698 const struct btf_array *array = btf_type_array(v->t);
1699 const struct btf_type *elem_type, *index_type;
1700 u32 elem_type_id, index_type_id;
1701 struct btf *btf = env->btf;
1704 /* Check array->index_type */
1705 index_type_id = array->index_type;
1706 index_type = btf_type_by_id(btf, index_type_id);
1707 if (btf_type_nosize_or_null(index_type)) {
1708 btf_verifier_log_type(env, v->t, "Invalid index");
1712 if (!env_type_is_resolve_sink(env, index_type) &&
1713 !env_type_is_resolved(env, index_type_id))
1714 return env_stack_push(env, index_type, index_type_id);
1716 index_type = btf_type_id_size(btf, &index_type_id, NULL);
1717 if (!index_type || !btf_type_is_int(index_type) ||
1718 !btf_type_int_is_regular(index_type)) {
1719 btf_verifier_log_type(env, v->t, "Invalid index");
1723 /* Check array->type */
1724 elem_type_id = array->type;
1725 elem_type = btf_type_by_id(btf, elem_type_id);
1726 if (btf_type_nosize_or_null(elem_type)) {
1727 btf_verifier_log_type(env, v->t,
1732 if (!env_type_is_resolve_sink(env, elem_type) &&
1733 !env_type_is_resolved(env, elem_type_id))
1734 return env_stack_push(env, elem_type, elem_type_id);
1736 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1738 btf_verifier_log_type(env, v->t, "Invalid elem");
1742 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
1743 btf_verifier_log_type(env, v->t, "Invalid array of int");
1747 if (array->nelems && elem_size > U32_MAX / array->nelems) {
1748 btf_verifier_log_type(env, v->t,
1749 "Array size overflows U32_MAX");
1753 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
1758 static void btf_array_log(struct btf_verifier_env *env,
1759 const struct btf_type *t)
1761 const struct btf_array *array = btf_type_array(t);
1763 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
1764 array->type, array->index_type, array->nelems);
1767 static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t,
1768 u32 type_id, void *data, u8 bits_offset,
1771 const struct btf_array *array = btf_type_array(t);
1772 const struct btf_kind_operations *elem_ops;
1773 const struct btf_type *elem_type;
1774 u32 i, elem_size, elem_type_id;
1776 elem_type_id = array->type;
1777 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
1778 elem_ops = btf_type_ops(elem_type);
1780 for (i = 0; i < array->nelems; i++) {
1784 elem_ops->seq_show(btf, elem_type, elem_type_id, data,
1791 static struct btf_kind_operations array_ops = {
1792 .check_meta = btf_array_check_meta,
1793 .resolve = btf_array_resolve,
1794 .check_member = btf_array_check_member,
1795 .check_kflag_member = btf_generic_check_kflag_member,
1796 .log_details = btf_array_log,
1797 .seq_show = btf_array_seq_show,
1800 static int btf_struct_check_member(struct btf_verifier_env *env,
1801 const struct btf_type *struct_type,
1802 const struct btf_member *member,
1803 const struct btf_type *member_type)
1805 u32 struct_bits_off = member->offset;
1806 u32 struct_size, bytes_offset;
1808 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1809 btf_verifier_log_member(env, struct_type, member,
1810 "Member is not byte aligned");
1814 struct_size = struct_type->size;
1815 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1816 if (struct_size - bytes_offset < member_type->size) {
1817 btf_verifier_log_member(env, struct_type, member,
1818 "Member exceeds struct_size");
1825 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
1826 const struct btf_type *t,
1829 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
1830 const struct btf_member *member;
1831 u32 meta_needed, last_offset;
1832 struct btf *btf = env->btf;
1833 u32 struct_size = t->size;
1837 meta_needed = btf_type_vlen(t) * sizeof(*member);
1838 if (meta_left < meta_needed) {
1839 btf_verifier_log_basic(env, t,
1840 "meta_left:%u meta_needed:%u",
1841 meta_left, meta_needed);
1845 /* struct type either no name or a valid one */
1847 !btf_name_valid_identifier(env->btf, t->name_off)) {
1848 btf_verifier_log_type(env, t, "Invalid name");
1852 btf_verifier_log_type(env, t, NULL);
1855 for_each_member(i, t, member) {
1856 if (!btf_name_offset_valid(btf, member->name_off)) {
1857 btf_verifier_log_member(env, t, member,
1858 "Invalid member name_offset:%u",
1863 /* struct member either no name or a valid one */
1864 if (member->name_off &&
1865 !btf_name_valid_identifier(btf, member->name_off)) {
1866 btf_verifier_log_member(env, t, member, "Invalid name");
1869 /* A member cannot be in type void */
1870 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
1871 btf_verifier_log_member(env, t, member,
1876 offset = btf_member_bit_offset(t, member);
1877 if (is_union && offset) {
1878 btf_verifier_log_member(env, t, member,
1879 "Invalid member bits_offset");
1884 * ">" instead of ">=" because the last member could be
1887 if (last_offset > offset) {
1888 btf_verifier_log_member(env, t, member,
1889 "Invalid member bits_offset");
1893 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
1894 btf_verifier_log_member(env, t, member,
1895 "Member bits_offset exceeds its struct size");
1899 btf_verifier_log_member(env, t, member, NULL);
1900 last_offset = offset;
1906 static int btf_struct_resolve(struct btf_verifier_env *env,
1907 const struct resolve_vertex *v)
1909 const struct btf_member *member;
1913 /* Before continue resolving the next_member,
1914 * ensure the last member is indeed resolved to a
1915 * type with size info.
1917 if (v->next_member) {
1918 const struct btf_type *last_member_type;
1919 const struct btf_member *last_member;
1920 u16 last_member_type_id;
1922 last_member = btf_type_member(v->t) + v->next_member - 1;
1923 last_member_type_id = last_member->type;
1924 if (WARN_ON_ONCE(!env_type_is_resolved(env,
1925 last_member_type_id)))
1928 last_member_type = btf_type_by_id(env->btf,
1929 last_member_type_id);
1930 if (btf_type_kflag(v->t))
1931 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
1935 err = btf_type_ops(last_member_type)->check_member(env, v->t,
1942 for_each_member_from(i, v->next_member, v->t, member) {
1943 u32 member_type_id = member->type;
1944 const struct btf_type *member_type = btf_type_by_id(env->btf,
1947 if (btf_type_nosize_or_null(member_type)) {
1948 btf_verifier_log_member(env, v->t, member,
1953 if (!env_type_is_resolve_sink(env, member_type) &&
1954 !env_type_is_resolved(env, member_type_id)) {
1955 env_stack_set_next_member(env, i + 1);
1956 return env_stack_push(env, member_type, member_type_id);
1959 if (btf_type_kflag(v->t))
1960 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
1964 err = btf_type_ops(member_type)->check_member(env, v->t,
1971 env_stack_pop_resolved(env, 0, 0);
1976 static void btf_struct_log(struct btf_verifier_env *env,
1977 const struct btf_type *t)
1979 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
1982 static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t,
1983 u32 type_id, void *data, u8 bits_offset,
1986 const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ",";
1987 const struct btf_member *member;
1991 for_each_member(i, t, member) {
1992 const struct btf_type *member_type = btf_type_by_id(btf,
1994 const struct btf_kind_operations *ops;
1995 u32 member_offset, bitfield_size;
2002 member_offset = btf_member_bit_offset(t, member);
2003 bitfield_size = btf_member_bitfield_size(t, member);
2004 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
2005 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
2006 if (bitfield_size) {
2007 btf_bitfield_seq_show(data + bytes_offset, bits8_offset,
2010 ops = btf_type_ops(member_type);
2011 ops->seq_show(btf, member_type, member->type,
2012 data + bytes_offset, bits8_offset, m);
2018 static struct btf_kind_operations struct_ops = {
2019 .check_meta = btf_struct_check_meta,
2020 .resolve = btf_struct_resolve,
2021 .check_member = btf_struct_check_member,
2022 .check_kflag_member = btf_generic_check_kflag_member,
2023 .log_details = btf_struct_log,
2024 .seq_show = btf_struct_seq_show,
2027 static int btf_enum_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 struct_bits_off = member->offset;
2033 u32 struct_size, bytes_offset;
2035 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2036 btf_verifier_log_member(env, struct_type, member,
2037 "Member is not byte aligned");
2041 struct_size = struct_type->size;
2042 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2043 if (struct_size - bytes_offset < sizeof(int)) {
2044 btf_verifier_log_member(env, struct_type, member,
2045 "Member exceeds struct_size");
2052 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
2053 const struct btf_type *struct_type,
2054 const struct btf_member *member,
2055 const struct btf_type *member_type)
2057 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
2058 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
2060 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2061 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2063 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2064 btf_verifier_log_member(env, struct_type, member,
2065 "Member is not byte aligned");
2069 nr_bits = int_bitsize;
2070 } else if (nr_bits > int_bitsize) {
2071 btf_verifier_log_member(env, struct_type, member,
2072 "Invalid member bitfield_size");
2076 struct_size = struct_type->size;
2077 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
2078 if (struct_size < bytes_end) {
2079 btf_verifier_log_member(env, struct_type, member,
2080 "Member exceeds struct_size");
2087 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
2088 const struct btf_type *t,
2091 const struct btf_enum *enums = btf_type_enum(t);
2092 struct btf *btf = env->btf;
2096 nr_enums = btf_type_vlen(t);
2097 meta_needed = nr_enums * sizeof(*enums);
2099 if (meta_left < meta_needed) {
2100 btf_verifier_log_basic(env, t,
2101 "meta_left:%u meta_needed:%u",
2102 meta_left, meta_needed);
2106 if (btf_type_kflag(t)) {
2107 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2111 if (t->size != sizeof(int)) {
2112 btf_verifier_log_type(env, t, "Expected size:%zu",
2117 /* enum type either no name or a valid one */
2119 !btf_name_valid_identifier(env->btf, t->name_off)) {
2120 btf_verifier_log_type(env, t, "Invalid name");
2124 btf_verifier_log_type(env, t, NULL);
2126 for (i = 0; i < nr_enums; i++) {
2127 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
2128 btf_verifier_log(env, "\tInvalid name_offset:%u",
2133 /* enum member must have a valid name */
2134 if (!enums[i].name_off ||
2135 !btf_name_valid_identifier(btf, enums[i].name_off)) {
2136 btf_verifier_log_type(env, t, "Invalid name");
2141 btf_verifier_log(env, "\t%s val=%d\n",
2142 __btf_name_by_offset(btf, enums[i].name_off),
2149 static void btf_enum_log(struct btf_verifier_env *env,
2150 const struct btf_type *t)
2152 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
2155 static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t,
2156 u32 type_id, void *data, u8 bits_offset,
2159 const struct btf_enum *enums = btf_type_enum(t);
2160 u32 i, nr_enums = btf_type_vlen(t);
2161 int v = *(int *)data;
2163 for (i = 0; i < nr_enums; i++) {
2164 if (v == enums[i].val) {
2166 __btf_name_by_offset(btf,
2167 enums[i].name_off));
2172 seq_printf(m, "%d", v);
2175 static struct btf_kind_operations enum_ops = {
2176 .check_meta = btf_enum_check_meta,
2177 .resolve = btf_df_resolve,
2178 .check_member = btf_enum_check_member,
2179 .check_kflag_member = btf_enum_check_kflag_member,
2180 .log_details = btf_enum_log,
2181 .seq_show = btf_enum_seq_show,
2184 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
2185 const struct btf_type *t,
2188 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
2190 if (meta_left < meta_needed) {
2191 btf_verifier_log_basic(env, t,
2192 "meta_left:%u meta_needed:%u",
2193 meta_left, meta_needed);
2198 btf_verifier_log_type(env, t, "Invalid name");
2202 if (btf_type_kflag(t)) {
2203 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2207 btf_verifier_log_type(env, t, NULL);
2212 static void btf_func_proto_log(struct btf_verifier_env *env,
2213 const struct btf_type *t)
2215 const struct btf_param *args = (const struct btf_param *)(t + 1);
2216 u16 nr_args = btf_type_vlen(t), i;
2218 btf_verifier_log(env, "return=%u args=(", t->type);
2220 btf_verifier_log(env, "void");
2224 if (nr_args == 1 && !args[0].type) {
2225 /* Only one vararg */
2226 btf_verifier_log(env, "vararg");
2230 btf_verifier_log(env, "%u %s", args[0].type,
2231 __btf_name_by_offset(env->btf,
2233 for (i = 1; i < nr_args - 1; i++)
2234 btf_verifier_log(env, ", %u %s", args[i].type,
2235 __btf_name_by_offset(env->btf,
2239 const struct btf_param *last_arg = &args[nr_args - 1];
2242 btf_verifier_log(env, ", %u %s", last_arg->type,
2243 __btf_name_by_offset(env->btf,
2244 last_arg->name_off));
2246 btf_verifier_log(env, ", vararg");
2250 btf_verifier_log(env, ")");
2253 static struct btf_kind_operations func_proto_ops = {
2254 .check_meta = btf_func_proto_check_meta,
2255 .resolve = btf_df_resolve,
2257 * BTF_KIND_FUNC_PROTO cannot be directly referred by
2258 * a struct's member.
2260 * It should be a funciton pointer instead.
2261 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
2263 * Hence, there is no btf_func_check_member().
2265 .check_member = btf_df_check_member,
2266 .check_kflag_member = btf_df_check_kflag_member,
2267 .log_details = btf_func_proto_log,
2268 .seq_show = btf_df_seq_show,
2271 static s32 btf_func_check_meta(struct btf_verifier_env *env,
2272 const struct btf_type *t,
2276 !btf_name_valid_identifier(env->btf, t->name_off)) {
2277 btf_verifier_log_type(env, t, "Invalid name");
2281 if (btf_type_vlen(t)) {
2282 btf_verifier_log_type(env, t, "vlen != 0");
2286 if (btf_type_kflag(t)) {
2287 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2291 btf_verifier_log_type(env, t, NULL);
2296 static struct btf_kind_operations func_ops = {
2297 .check_meta = btf_func_check_meta,
2298 .resolve = btf_df_resolve,
2299 .check_member = btf_df_check_member,
2300 .check_kflag_member = btf_df_check_kflag_member,
2301 .log_details = btf_ref_type_log,
2302 .seq_show = btf_df_seq_show,
2305 static int btf_func_proto_check(struct btf_verifier_env *env,
2306 const struct btf_type *t)
2308 const struct btf_type *ret_type;
2309 const struct btf_param *args;
2310 const struct btf *btf;
2315 args = (const struct btf_param *)(t + 1);
2316 nr_args = btf_type_vlen(t);
2318 /* Check func return type which could be "void" (t->type == 0) */
2320 u32 ret_type_id = t->type;
2322 ret_type = btf_type_by_id(btf, ret_type_id);
2324 btf_verifier_log_type(env, t, "Invalid return type");
2328 if (btf_type_needs_resolve(ret_type) &&
2329 !env_type_is_resolved(env, ret_type_id)) {
2330 err = btf_resolve(env, ret_type, ret_type_id);
2335 /* Ensure the return type is a type that has a size */
2336 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
2337 btf_verifier_log_type(env, t, "Invalid return type");
2345 /* Last func arg type_id could be 0 if it is a vararg */
2346 if (!args[nr_args - 1].type) {
2347 if (args[nr_args - 1].name_off) {
2348 btf_verifier_log_type(env, t, "Invalid arg#%u",
2356 for (i = 0; i < nr_args; i++) {
2357 const struct btf_type *arg_type;
2360 arg_type_id = args[i].type;
2361 arg_type = btf_type_by_id(btf, arg_type_id);
2363 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2368 if (args[i].name_off &&
2369 (!btf_name_offset_valid(btf, args[i].name_off) ||
2370 !btf_name_valid_identifier(btf, args[i].name_off))) {
2371 btf_verifier_log_type(env, t,
2372 "Invalid arg#%u", i + 1);
2377 if (btf_type_needs_resolve(arg_type) &&
2378 !env_type_is_resolved(env, arg_type_id)) {
2379 err = btf_resolve(env, arg_type, arg_type_id);
2384 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
2385 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2394 static int btf_func_check(struct btf_verifier_env *env,
2395 const struct btf_type *t)
2397 const struct btf_type *proto_type;
2398 const struct btf_param *args;
2399 const struct btf *btf;
2403 proto_type = btf_type_by_id(btf, t->type);
2405 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
2406 btf_verifier_log_type(env, t, "Invalid type_id");
2410 args = (const struct btf_param *)(proto_type + 1);
2411 nr_args = btf_type_vlen(proto_type);
2412 for (i = 0; i < nr_args; i++) {
2413 if (!args[i].name_off && args[i].type) {
2414 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
2422 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
2423 [BTF_KIND_INT] = &int_ops,
2424 [BTF_KIND_PTR] = &ptr_ops,
2425 [BTF_KIND_ARRAY] = &array_ops,
2426 [BTF_KIND_STRUCT] = &struct_ops,
2427 [BTF_KIND_UNION] = &struct_ops,
2428 [BTF_KIND_ENUM] = &enum_ops,
2429 [BTF_KIND_FWD] = &fwd_ops,
2430 [BTF_KIND_TYPEDEF] = &modifier_ops,
2431 [BTF_KIND_VOLATILE] = &modifier_ops,
2432 [BTF_KIND_CONST] = &modifier_ops,
2433 [BTF_KIND_RESTRICT] = &modifier_ops,
2434 [BTF_KIND_FUNC] = &func_ops,
2435 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
2438 static s32 btf_check_meta(struct btf_verifier_env *env,
2439 const struct btf_type *t,
2442 u32 saved_meta_left = meta_left;
2445 if (meta_left < sizeof(*t)) {
2446 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
2447 env->log_type_id, meta_left, sizeof(*t));
2450 meta_left -= sizeof(*t);
2452 if (t->info & ~BTF_INFO_MASK) {
2453 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
2454 env->log_type_id, t->info);
2458 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
2459 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
2460 btf_verifier_log(env, "[%u] Invalid kind:%u",
2461 env->log_type_id, BTF_INFO_KIND(t->info));
2465 if (!btf_name_offset_valid(env->btf, t->name_off)) {
2466 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
2467 env->log_type_id, t->name_off);
2471 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
2472 if (var_meta_size < 0)
2473 return var_meta_size;
2475 meta_left -= var_meta_size;
2477 return saved_meta_left - meta_left;
2480 static int btf_check_all_metas(struct btf_verifier_env *env)
2482 struct btf *btf = env->btf;
2483 struct btf_header *hdr;
2487 cur = btf->nohdr_data + hdr->type_off;
2488 end = cur + hdr->type_len;
2490 env->log_type_id = 1;
2492 struct btf_type *t = cur;
2495 meta_size = btf_check_meta(env, t, end - cur);
2499 btf_add_type(env, t);
2507 static bool btf_resolve_valid(struct btf_verifier_env *env,
2508 const struct btf_type *t,
2511 struct btf *btf = env->btf;
2513 if (!env_type_is_resolved(env, type_id))
2516 if (btf_type_is_struct(t))
2517 return !btf->resolved_ids[type_id] &&
2518 !btf->resolved_sizes[type_id];
2520 if (btf_type_is_modifier(t) || btf_type_is_ptr(t)) {
2521 t = btf_type_id_resolve(btf, &type_id);
2522 return t && !btf_type_is_modifier(t);
2525 if (btf_type_is_array(t)) {
2526 const struct btf_array *array = btf_type_array(t);
2527 const struct btf_type *elem_type;
2528 u32 elem_type_id = array->type;
2531 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2532 return elem_type && !btf_type_is_modifier(elem_type) &&
2533 (array->nelems * elem_size ==
2534 btf->resolved_sizes[type_id]);
2540 static int btf_resolve(struct btf_verifier_env *env,
2541 const struct btf_type *t, u32 type_id)
2543 u32 save_log_type_id = env->log_type_id;
2544 const struct resolve_vertex *v;
2547 env->resolve_mode = RESOLVE_TBD;
2548 env_stack_push(env, t, type_id);
2549 while (!err && (v = env_stack_peak(env))) {
2550 env->log_type_id = v->type_id;
2551 err = btf_type_ops(v->t)->resolve(env, v);
2554 env->log_type_id = type_id;
2555 if (err == -E2BIG) {
2556 btf_verifier_log_type(env, t,
2557 "Exceeded max resolving depth:%u",
2559 } else if (err == -EEXIST) {
2560 btf_verifier_log_type(env, t, "Loop detected");
2563 /* Final sanity check */
2564 if (!err && !btf_resolve_valid(env, t, type_id)) {
2565 btf_verifier_log_type(env, t, "Invalid resolve state");
2569 env->log_type_id = save_log_type_id;
2573 static int btf_check_all_types(struct btf_verifier_env *env)
2575 struct btf *btf = env->btf;
2579 err = env_resolve_init(env);
2584 for (type_id = 1; type_id <= btf->nr_types; type_id++) {
2585 const struct btf_type *t = btf_type_by_id(btf, type_id);
2587 env->log_type_id = type_id;
2588 if (btf_type_needs_resolve(t) &&
2589 !env_type_is_resolved(env, type_id)) {
2590 err = btf_resolve(env, t, type_id);
2595 if (btf_type_is_func_proto(t)) {
2596 err = btf_func_proto_check(env, t);
2601 if (btf_type_is_func(t)) {
2602 err = btf_func_check(env, t);
2611 static int btf_parse_type_sec(struct btf_verifier_env *env)
2613 const struct btf_header *hdr = &env->btf->hdr;
2616 /* Type section must align to 4 bytes */
2617 if (hdr->type_off & (sizeof(u32) - 1)) {
2618 btf_verifier_log(env, "Unaligned type_off");
2622 if (!hdr->type_len) {
2623 btf_verifier_log(env, "No type found");
2627 err = btf_check_all_metas(env);
2631 return btf_check_all_types(env);
2634 static int btf_parse_str_sec(struct btf_verifier_env *env)
2636 const struct btf_header *hdr;
2637 struct btf *btf = env->btf;
2638 const char *start, *end;
2641 start = btf->nohdr_data + hdr->str_off;
2642 end = start + hdr->str_len;
2644 if (end != btf->data + btf->data_size) {
2645 btf_verifier_log(env, "String section is not at the end");
2649 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET ||
2650 start[0] || end[-1]) {
2651 btf_verifier_log(env, "Invalid string section");
2655 btf->strings = start;
2660 static const size_t btf_sec_info_offset[] = {
2661 offsetof(struct btf_header, type_off),
2662 offsetof(struct btf_header, str_off),
2665 static int btf_sec_info_cmp(const void *a, const void *b)
2667 const struct btf_sec_info *x = a;
2668 const struct btf_sec_info *y = b;
2670 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
2673 static int btf_check_sec_info(struct btf_verifier_env *env,
2676 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
2677 u32 total, expected_total, i;
2678 const struct btf_header *hdr;
2679 const struct btf *btf;
2684 /* Populate the secs from hdr */
2685 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
2686 secs[i] = *(struct btf_sec_info *)((void *)hdr +
2687 btf_sec_info_offset[i]);
2689 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
2690 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
2692 /* Check for gaps and overlap among sections */
2694 expected_total = btf_data_size - hdr->hdr_len;
2695 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
2696 if (expected_total < secs[i].off) {
2697 btf_verifier_log(env, "Invalid section offset");
2700 if (total < secs[i].off) {
2702 btf_verifier_log(env, "Unsupported section found");
2705 if (total > secs[i].off) {
2706 btf_verifier_log(env, "Section overlap found");
2709 if (expected_total - total < secs[i].len) {
2710 btf_verifier_log(env,
2711 "Total section length too long");
2714 total += secs[i].len;
2717 /* There is data other than hdr and known sections */
2718 if (expected_total != total) {
2719 btf_verifier_log(env, "Unsupported section found");
2726 static int btf_parse_hdr(struct btf_verifier_env *env)
2728 u32 hdr_len, hdr_copy, btf_data_size;
2729 const struct btf_header *hdr;
2734 btf_data_size = btf->data_size;
2737 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
2738 btf_verifier_log(env, "hdr_len not found");
2743 hdr_len = hdr->hdr_len;
2744 if (btf_data_size < hdr_len) {
2745 btf_verifier_log(env, "btf_header not found");
2749 /* Ensure the unsupported header fields are zero */
2750 if (hdr_len > sizeof(btf->hdr)) {
2751 u8 *expected_zero = btf->data + sizeof(btf->hdr);
2752 u8 *end = btf->data + hdr_len;
2754 for (; expected_zero < end; expected_zero++) {
2755 if (*expected_zero) {
2756 btf_verifier_log(env, "Unsupported btf_header");
2762 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
2763 memcpy(&btf->hdr, btf->data, hdr_copy);
2767 btf_verifier_log_hdr(env, btf_data_size);
2769 if (hdr->magic != BTF_MAGIC) {
2770 btf_verifier_log(env, "Invalid magic");
2774 if (hdr->version != BTF_VERSION) {
2775 btf_verifier_log(env, "Unsupported version");
2780 btf_verifier_log(env, "Unsupported flags");
2784 if (btf_data_size == hdr->hdr_len) {
2785 btf_verifier_log(env, "No data");
2789 err = btf_check_sec_info(env, btf_data_size);
2796 static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size,
2797 u32 log_level, char __user *log_ubuf, u32 log_size)
2799 struct btf_verifier_env *env = NULL;
2800 struct bpf_verifier_log *log;
2801 struct btf *btf = NULL;
2805 if (btf_data_size > BTF_MAX_SIZE)
2806 return ERR_PTR(-E2BIG);
2808 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
2810 return ERR_PTR(-ENOMEM);
2813 if (log_level || log_ubuf || log_size) {
2814 /* user requested verbose verifier output
2815 * and supplied buffer to store the verification trace
2817 log->level = log_level;
2818 log->ubuf = log_ubuf;
2819 log->len_total = log_size;
2821 /* log attributes have to be sane */
2822 if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 ||
2823 !log->level || !log->ubuf) {
2829 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
2836 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
2843 btf->data_size = btf_data_size;
2845 if (copy_from_user(data, btf_data, btf_data_size)) {
2850 err = btf_parse_hdr(env);
2854 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
2856 err = btf_parse_str_sec(env);
2860 err = btf_parse_type_sec(env);
2864 if (log->level && bpf_verifier_log_full(log)) {
2869 btf_verifier_env_free(env);
2870 refcount_set(&btf->refcnt, 1);
2874 btf_verifier_env_free(env);
2877 return ERR_PTR(err);
2880 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
2883 const struct btf_type *t = btf_type_by_id(btf, type_id);
2885 btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m);
2888 static int btf_release(struct inode *inode, struct file *filp)
2890 btf_put(filp->private_data);
2894 const struct file_operations btf_fops = {
2895 .release = btf_release,
2898 static int __btf_new_fd(struct btf *btf)
2900 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
2903 int btf_new_fd(const union bpf_attr *attr)
2908 btf = btf_parse(u64_to_user_ptr(attr->btf),
2909 attr->btf_size, attr->btf_log_level,
2910 u64_to_user_ptr(attr->btf_log_buf),
2911 attr->btf_log_size);
2913 return PTR_ERR(btf);
2915 ret = btf_alloc_id(btf);
2922 * The BTF ID is published to the userspace.
2923 * All BTF free must go through call_rcu() from
2924 * now on (i.e. free by calling btf_put()).
2927 ret = __btf_new_fd(btf);
2934 struct btf *btf_get_by_fd(int fd)
2942 return ERR_PTR(-EBADF);
2944 if (f.file->f_op != &btf_fops) {
2946 return ERR_PTR(-EINVAL);
2949 btf = f.file->private_data;
2950 refcount_inc(&btf->refcnt);
2956 int btf_get_info_by_fd(const struct btf *btf,
2957 const union bpf_attr *attr,
2958 union bpf_attr __user *uattr)
2960 struct bpf_btf_info __user *uinfo;
2961 struct bpf_btf_info info = {};
2962 u32 info_copy, btf_copy;
2966 uinfo = u64_to_user_ptr(attr->info.info);
2967 uinfo_len = attr->info.info_len;
2969 info_copy = min_t(u32, uinfo_len, sizeof(info));
2970 if (copy_from_user(&info, uinfo, info_copy))
2974 ubtf = u64_to_user_ptr(info.btf);
2975 btf_copy = min_t(u32, btf->data_size, info.btf_size);
2976 if (copy_to_user(ubtf, btf->data, btf_copy))
2978 info.btf_size = btf->data_size;
2980 if (copy_to_user(uinfo, &info, info_copy) ||
2981 put_user(info_copy, &uattr->info.info_len))
2987 int btf_get_fd_by_id(u32 id)
2993 btf = idr_find(&btf_idr, id);
2994 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
2995 btf = ERR_PTR(-ENOENT);
2999 return PTR_ERR(btf);
3001 fd = __btf_new_fd(btf);
3008 u32 btf_id(const struct btf *btf)