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);
203 struct btf_type **types;
208 struct btf_header hdr;
209 u32 nr_types; /* includes VOID for base BTF */
216 /* split BTF support */
217 struct btf *base_btf;
218 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
219 u32 start_str_off; /* first string offset (0 for base BTF) */
220 char name[MODULE_NAME_LEN];
224 enum verifier_phase {
229 struct resolve_vertex {
230 const struct btf_type *t;
242 RESOLVE_TBD, /* To Be Determined */
243 RESOLVE_PTR, /* Resolving for Pointer */
244 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
249 #define MAX_RESOLVE_DEPTH 32
251 struct btf_sec_info {
256 struct btf_verifier_env {
259 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
260 struct bpf_verifier_log log;
263 enum verifier_phase phase;
264 enum resolve_mode resolve_mode;
267 static const char * const btf_kind_str[NR_BTF_KINDS] = {
268 [BTF_KIND_UNKN] = "UNKNOWN",
269 [BTF_KIND_INT] = "INT",
270 [BTF_KIND_PTR] = "PTR",
271 [BTF_KIND_ARRAY] = "ARRAY",
272 [BTF_KIND_STRUCT] = "STRUCT",
273 [BTF_KIND_UNION] = "UNION",
274 [BTF_KIND_ENUM] = "ENUM",
275 [BTF_KIND_FWD] = "FWD",
276 [BTF_KIND_TYPEDEF] = "TYPEDEF",
277 [BTF_KIND_VOLATILE] = "VOLATILE",
278 [BTF_KIND_CONST] = "CONST",
279 [BTF_KIND_RESTRICT] = "RESTRICT",
280 [BTF_KIND_FUNC] = "FUNC",
281 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
282 [BTF_KIND_VAR] = "VAR",
283 [BTF_KIND_DATASEC] = "DATASEC",
284 [BTF_KIND_FLOAT] = "FLOAT",
285 [BTF_KIND_DECL_TAG] = "DECL_TAG",
286 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
289 const char *btf_type_str(const struct btf_type *t)
291 return btf_kind_str[BTF_INFO_KIND(t->info)];
294 /* Chunk size we use in safe copy of data to be shown. */
295 #define BTF_SHOW_OBJ_SAFE_SIZE 32
298 * This is the maximum size of a base type value (equivalent to a
299 * 128-bit int); if we are at the end of our safe buffer and have
300 * less than 16 bytes space we can't be assured of being able
301 * to copy the next type safely, so in such cases we will initiate
304 #define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
307 #define BTF_SHOW_NAME_SIZE 80
310 * Common data to all BTF show operations. Private show functions can add
311 * their own data to a structure containing a struct btf_show and consult it
312 * in the show callback. See btf_type_show() below.
314 * One challenge with showing nested data is we want to skip 0-valued
315 * data, but in order to figure out whether a nested object is all zeros
316 * we need to walk through it. As a result, we need to make two passes
317 * when handling structs, unions and arrays; the first path simply looks
318 * for nonzero data, while the second actually does the display. The first
319 * pass is signalled by show->state.depth_check being set, and if we
320 * encounter a non-zero value we set show->state.depth_to_show to
321 * the depth at which we encountered it. When we have completed the
322 * first pass, we will know if anything needs to be displayed if
323 * depth_to_show > depth. See btf_[struct,array]_show() for the
324 * implementation of this.
326 * Another problem is we want to ensure the data for display is safe to
327 * access. To support this, the anonymous "struct {} obj" tracks the data
328 * object and our safe copy of it. We copy portions of the data needed
329 * to the object "copy" buffer, but because its size is limited to
330 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
331 * traverse larger objects for display.
333 * The various data type show functions all start with a call to
334 * btf_show_start_type() which returns a pointer to the safe copy
335 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
336 * raw data itself). btf_show_obj_safe() is responsible for
337 * using copy_from_kernel_nofault() to update the safe data if necessary
338 * as we traverse the object's data. skbuff-like semantics are
341 * - obj.head points to the start of the toplevel object for display
342 * - obj.size is the size of the toplevel object
343 * - obj.data points to the current point in the original data at
344 * which our safe data starts. obj.data will advance as we copy
345 * portions of the data.
347 * In most cases a single copy will suffice, but larger data structures
348 * such as "struct task_struct" will require many copies. The logic in
349 * btf_show_obj_safe() handles the logic that determines if a new
350 * copy_from_kernel_nofault() is needed.
354 void *target; /* target of show operation (seq file, buffer) */
355 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
356 const struct btf *btf;
357 /* below are used during iteration */
366 int status; /* non-zero for error */
367 const struct btf_type *type;
368 const struct btf_member *member;
369 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
375 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
379 struct btf_kind_operations {
380 s32 (*check_meta)(struct btf_verifier_env *env,
381 const struct btf_type *t,
383 int (*resolve)(struct btf_verifier_env *env,
384 const struct resolve_vertex *v);
385 int (*check_member)(struct btf_verifier_env *env,
386 const struct btf_type *struct_type,
387 const struct btf_member *member,
388 const struct btf_type *member_type);
389 int (*check_kflag_member)(struct btf_verifier_env *env,
390 const struct btf_type *struct_type,
391 const struct btf_member *member,
392 const struct btf_type *member_type);
393 void (*log_details)(struct btf_verifier_env *env,
394 const struct btf_type *t);
395 void (*show)(const struct btf *btf, const struct btf_type *t,
396 u32 type_id, void *data, u8 bits_offsets,
397 struct btf_show *show);
400 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
401 static struct btf_type btf_void;
403 static int btf_resolve(struct btf_verifier_env *env,
404 const struct btf_type *t, u32 type_id);
406 static int btf_func_check(struct btf_verifier_env *env,
407 const struct btf_type *t);
409 static bool btf_type_is_modifier(const struct btf_type *t)
411 /* Some of them is not strictly a C modifier
412 * but they are grouped into the same bucket
414 * A type (t) that refers to another
415 * type through t->type AND its size cannot
416 * be determined without following the t->type.
418 * ptr does not fall into this bucket
419 * because its size is always sizeof(void *).
421 switch (BTF_INFO_KIND(t->info)) {
422 case BTF_KIND_TYPEDEF:
423 case BTF_KIND_VOLATILE:
425 case BTF_KIND_RESTRICT:
426 case BTF_KIND_TYPE_TAG:
433 bool btf_type_is_void(const struct btf_type *t)
435 return t == &btf_void;
438 static bool btf_type_is_fwd(const struct btf_type *t)
440 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
443 static bool btf_type_nosize(const struct btf_type *t)
445 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
446 btf_type_is_func(t) || btf_type_is_func_proto(t);
449 static bool btf_type_nosize_or_null(const struct btf_type *t)
451 return !t || btf_type_nosize(t);
454 static bool __btf_type_is_struct(const struct btf_type *t)
456 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
459 static bool btf_type_is_array(const struct btf_type *t)
461 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
464 static bool btf_type_is_datasec(const struct btf_type *t)
466 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
469 static bool btf_type_is_decl_tag(const struct btf_type *t)
471 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
474 static bool btf_type_is_decl_tag_target(const struct btf_type *t)
476 return btf_type_is_func(t) || btf_type_is_struct(t) ||
477 btf_type_is_var(t) || btf_type_is_typedef(t);
480 u32 btf_nr_types(const struct btf *btf)
485 total += btf->nr_types;
492 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
494 const struct btf_type *t;
498 total = btf_nr_types(btf);
499 for (i = 1; i < total; i++) {
500 t = btf_type_by_id(btf, i);
501 if (BTF_INFO_KIND(t->info) != kind)
504 tname = btf_name_by_offset(btf, t->name_off);
505 if (!strcmp(tname, name))
512 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
515 const struct btf_type *t = btf_type_by_id(btf, id);
517 while (btf_type_is_modifier(t)) {
519 t = btf_type_by_id(btf, t->type);
528 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
531 const struct btf_type *t;
533 t = btf_type_skip_modifiers(btf, id, NULL);
534 if (!btf_type_is_ptr(t))
537 return btf_type_skip_modifiers(btf, t->type, res_id);
540 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
543 const struct btf_type *ptype;
545 ptype = btf_type_resolve_ptr(btf, id, res_id);
546 if (ptype && btf_type_is_func_proto(ptype))
552 /* Types that act only as a source, not sink or intermediate
553 * type when resolving.
555 static bool btf_type_is_resolve_source_only(const struct btf_type *t)
557 return btf_type_is_var(t) ||
558 btf_type_is_decl_tag(t) ||
559 btf_type_is_datasec(t);
562 /* What types need to be resolved?
564 * btf_type_is_modifier() is an obvious one.
566 * btf_type_is_struct() because its member refers to
567 * another type (through member->type).
569 * btf_type_is_var() because the variable refers to
570 * another type. btf_type_is_datasec() holds multiple
571 * btf_type_is_var() types that need resolving.
573 * btf_type_is_array() because its element (array->type)
574 * refers to another type. Array can be thought of a
575 * special case of struct while array just has the same
576 * member-type repeated by array->nelems of times.
578 static bool btf_type_needs_resolve(const struct btf_type *t)
580 return btf_type_is_modifier(t) ||
581 btf_type_is_ptr(t) ||
582 btf_type_is_struct(t) ||
583 btf_type_is_array(t) ||
584 btf_type_is_var(t) ||
585 btf_type_is_func(t) ||
586 btf_type_is_decl_tag(t) ||
587 btf_type_is_datasec(t);
590 /* t->size can be used */
591 static bool btf_type_has_size(const struct btf_type *t)
593 switch (BTF_INFO_KIND(t->info)) {
595 case BTF_KIND_STRUCT:
598 case BTF_KIND_DATASEC:
606 static const char *btf_int_encoding_str(u8 encoding)
610 else if (encoding == BTF_INT_SIGNED)
612 else if (encoding == BTF_INT_CHAR)
614 else if (encoding == BTF_INT_BOOL)
620 static u32 btf_type_int(const struct btf_type *t)
622 return *(u32 *)(t + 1);
625 static const struct btf_array *btf_type_array(const struct btf_type *t)
627 return (const struct btf_array *)(t + 1);
630 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
632 return (const struct btf_enum *)(t + 1);
635 static const struct btf_var *btf_type_var(const struct btf_type *t)
637 return (const struct btf_var *)(t + 1);
640 static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
642 return (const struct btf_decl_tag *)(t + 1);
645 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
647 return kind_ops[BTF_INFO_KIND(t->info)];
650 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
652 if (!BTF_STR_OFFSET_VALID(offset))
655 while (offset < btf->start_str_off)
658 offset -= btf->start_str_off;
659 return offset < btf->hdr.str_len;
662 static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
664 if ((first ? !isalpha(c) :
667 ((c == '.' && !dot_ok) ||
673 static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
675 while (offset < btf->start_str_off)
678 offset -= btf->start_str_off;
679 if (offset < btf->hdr.str_len)
680 return &btf->strings[offset];
685 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
687 /* offset must be valid */
688 const char *src = btf_str_by_offset(btf, offset);
689 const char *src_limit;
691 if (!__btf_name_char_ok(*src, true, dot_ok))
694 /* set a limit on identifier length */
695 src_limit = src + KSYM_NAME_LEN;
697 while (*src && src < src_limit) {
698 if (!__btf_name_char_ok(*src, false, dot_ok))
706 /* Only C-style identifier is permitted. This can be relaxed if
709 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
711 return __btf_name_valid(btf, offset, false);
714 static bool btf_name_valid_section(const struct btf *btf, u32 offset)
716 return __btf_name_valid(btf, offset, true);
719 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
726 name = btf_str_by_offset(btf, offset);
727 return name ?: "(invalid-name-offset)";
730 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
732 return btf_str_by_offset(btf, offset);
735 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
737 while (type_id < btf->start_id)
740 type_id -= btf->start_id;
741 if (type_id >= btf->nr_types)
743 return btf->types[type_id];
747 * Regular int is not a bit field and it must be either
748 * u8/u16/u32/u64 or __int128.
750 static bool btf_type_int_is_regular(const struct btf_type *t)
752 u8 nr_bits, nr_bytes;
755 int_data = btf_type_int(t);
756 nr_bits = BTF_INT_BITS(int_data);
757 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
758 if (BITS_PER_BYTE_MASKED(nr_bits) ||
759 BTF_INT_OFFSET(int_data) ||
760 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
761 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
762 nr_bytes != (2 * sizeof(u64)))) {
770 * Check that given struct member is a regular int with expected
773 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
774 const struct btf_member *m,
775 u32 expected_offset, u32 expected_size)
777 const struct btf_type *t;
782 t = btf_type_id_size(btf, &id, NULL);
783 if (!t || !btf_type_is_int(t))
786 int_data = btf_type_int(t);
787 nr_bits = BTF_INT_BITS(int_data);
788 if (btf_type_kflag(s)) {
789 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
790 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
792 /* if kflag set, int should be a regular int and
793 * bit offset should be at byte boundary.
795 return !bitfield_size &&
796 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
797 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
800 if (BTF_INT_OFFSET(int_data) ||
801 BITS_PER_BYTE_MASKED(m->offset) ||
802 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
803 BITS_PER_BYTE_MASKED(nr_bits) ||
804 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
810 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
811 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
814 const struct btf_type *t = btf_type_by_id(btf, id);
816 while (btf_type_is_modifier(t) &&
817 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
818 t = btf_type_by_id(btf, t->type);
824 #define BTF_SHOW_MAX_ITER 10
826 #define BTF_KIND_BIT(kind) (1ULL << kind)
829 * Populate show->state.name with type name information.
830 * Format of type name is
832 * [.member_name = ] (type_name)
834 static const char *btf_show_name(struct btf_show *show)
836 /* BTF_MAX_ITER array suffixes "[]" */
837 const char *array_suffixes = "[][][][][][][][][][]";
838 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
839 /* BTF_MAX_ITER pointer suffixes "*" */
840 const char *ptr_suffixes = "**********";
841 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
842 const char *name = NULL, *prefix = "", *parens = "";
843 const struct btf_member *m = show->state.member;
844 const struct btf_type *t;
845 const struct btf_array *array;
846 u32 id = show->state.type_id;
847 const char *member = NULL;
848 bool show_member = false;
852 show->state.name[0] = '\0';
855 * Don't show type name if we're showing an array member;
856 * in that case we show the array type so don't need to repeat
857 * ourselves for each member.
859 if (show->state.array_member)
862 /* Retrieve member name, if any. */
864 member = btf_name_by_offset(show->btf, m->name_off);
865 show_member = strlen(member) > 0;
870 * Start with type_id, as we have resolved the struct btf_type *
871 * via btf_modifier_show() past the parent typedef to the child
872 * struct, int etc it is defined as. In such cases, the type_id
873 * still represents the starting type while the struct btf_type *
874 * in our show->state points at the resolved type of the typedef.
876 t = btf_type_by_id(show->btf, id);
881 * The goal here is to build up the right number of pointer and
882 * array suffixes while ensuring the type name for a typedef
883 * is represented. Along the way we accumulate a list of
884 * BTF kinds we have encountered, since these will inform later
885 * display; for example, pointer types will not require an
886 * opening "{" for struct, we will just display the pointer value.
888 * We also want to accumulate the right number of pointer or array
889 * indices in the format string while iterating until we get to
890 * the typedef/pointee/array member target type.
892 * We start by pointing at the end of pointer and array suffix
893 * strings; as we accumulate pointers and arrays we move the pointer
894 * or array string backwards so it will show the expected number of
895 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
896 * and/or arrays and typedefs are supported as a precaution.
898 * We also want to get typedef name while proceeding to resolve
899 * type it points to so that we can add parentheses if it is a
900 * "typedef struct" etc.
902 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
904 switch (BTF_INFO_KIND(t->info)) {
905 case BTF_KIND_TYPEDEF:
907 name = btf_name_by_offset(show->btf,
909 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
913 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
917 array = btf_type_array(t);
918 if (array_suffix > array_suffixes)
923 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
924 if (ptr_suffix > ptr_suffixes)
934 t = btf_type_skip_qualifiers(show->btf, id);
936 /* We may not be able to represent this type; bail to be safe */
937 if (i == BTF_SHOW_MAX_ITER)
941 name = btf_name_by_offset(show->btf, t->name_off);
943 switch (BTF_INFO_KIND(t->info)) {
944 case BTF_KIND_STRUCT:
946 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
948 /* if it's an array of struct/union, parens is already set */
949 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
959 /* pointer does not require parens */
960 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
962 /* typedef does not require struct/union/enum prefix */
963 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
969 /* Even if we don't want type name info, we want parentheses etc */
970 if (show->flags & BTF_SHOW_NONAME)
971 snprintf(show->state.name, sizeof(show->state.name), "%s",
974 snprintf(show->state.name, sizeof(show->state.name),
975 "%s%s%s(%s%s%s%s%s%s)%s",
976 /* first 3 strings comprise ".member = " */
977 show_member ? "." : "",
978 show_member ? member : "",
979 show_member ? " = " : "",
980 /* ...next is our prefix (struct, enum, etc) */
982 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
983 /* ...this is the type name itself */
985 /* ...suffixed by the appropriate '*', '[]' suffixes */
986 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
987 array_suffix, parens);
989 return show->state.name;
992 static const char *__btf_show_indent(struct btf_show *show)
994 const char *indents = " ";
995 const char *indent = &indents[strlen(indents)];
997 if ((indent - show->state.depth) >= indents)
998 return indent - show->state.depth;
1002 static const char *btf_show_indent(struct btf_show *show)
1004 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1007 static const char *btf_show_newline(struct btf_show *show)
1009 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1012 static const char *btf_show_delim(struct btf_show *show)
1014 if (show->state.depth == 0)
1017 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1018 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1024 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1028 if (!show->state.depth_check) {
1029 va_start(args, fmt);
1030 show->showfn(show, fmt, args);
1035 /* Macros are used here as btf_show_type_value[s]() prepends and appends
1036 * format specifiers to the format specifier passed in; these do the work of
1037 * adding indentation, delimiters etc while the caller simply has to specify
1038 * the type value(s) in the format specifier + value(s).
1040 #define btf_show_type_value(show, fmt, value) \
1042 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \
1043 show->state.depth == 0) { \
1044 btf_show(show, "%s%s" fmt "%s%s", \
1045 btf_show_indent(show), \
1046 btf_show_name(show), \
1047 value, btf_show_delim(show), \
1048 btf_show_newline(show)); \
1049 if (show->state.depth > show->state.depth_to_show) \
1050 show->state.depth_to_show = show->state.depth; \
1054 #define btf_show_type_values(show, fmt, ...) \
1056 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1057 btf_show_name(show), \
1058 __VA_ARGS__, btf_show_delim(show), \
1059 btf_show_newline(show)); \
1060 if (show->state.depth > show->state.depth_to_show) \
1061 show->state.depth_to_show = show->state.depth; \
1064 /* How much is left to copy to safe buffer after @data? */
1065 static int btf_show_obj_size_left(struct btf_show *show, void *data)
1067 return show->obj.head + show->obj.size - data;
1070 /* Is object pointed to by @data of @size already copied to our safe buffer? */
1071 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1073 return data >= show->obj.data &&
1074 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1078 * If object pointed to by @data of @size falls within our safe buffer, return
1079 * the equivalent pointer to the same safe data. Assumes
1080 * copy_from_kernel_nofault() has already happened and our safe buffer is
1083 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1085 if (btf_show_obj_is_safe(show, data, size))
1086 return show->obj.safe + (data - show->obj.data);
1091 * Return a safe-to-access version of data pointed to by @data.
1092 * We do this by copying the relevant amount of information
1093 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1095 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1096 * safe copy is needed.
1098 * Otherwise we need to determine if we have the required amount
1099 * of data (determined by the @data pointer and the size of the
1100 * largest base type we can encounter (represented by
1101 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1102 * that we will be able to print some of the current object,
1103 * and if more is needed a copy will be triggered.
1104 * Some objects such as structs will not fit into the buffer;
1105 * in such cases additional copies when we iterate over their
1106 * members may be needed.
1108 * btf_show_obj_safe() is used to return a safe buffer for
1109 * btf_show_start_type(); this ensures that as we recurse into
1110 * nested types we always have safe data for the given type.
1111 * This approach is somewhat wasteful; it's possible for example
1112 * that when iterating over a large union we'll end up copying the
1113 * same data repeatedly, but the goal is safety not performance.
1114 * We use stack data as opposed to per-CPU buffers because the
1115 * iteration over a type can take some time, and preemption handling
1116 * would greatly complicate use of the safe buffer.
1118 static void *btf_show_obj_safe(struct btf_show *show,
1119 const struct btf_type *t,
1122 const struct btf_type *rt;
1123 int size_left, size;
1126 if (show->flags & BTF_SHOW_UNSAFE)
1129 rt = btf_resolve_size(show->btf, t, &size);
1131 show->state.status = PTR_ERR(rt);
1136 * Is this toplevel object? If so, set total object size and
1137 * initialize pointers. Otherwise check if we still fall within
1138 * our safe object data.
1140 if (show->state.depth == 0) {
1141 show->obj.size = size;
1142 show->obj.head = data;
1145 * If the size of the current object is > our remaining
1146 * safe buffer we _may_ need to do a new copy. However
1147 * consider the case of a nested struct; it's size pushes
1148 * us over the safe buffer limit, but showing any individual
1149 * struct members does not. In such cases, we don't need
1150 * to initiate a fresh copy yet; however we definitely need
1151 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1152 * in our buffer, regardless of the current object size.
1153 * The logic here is that as we resolve types we will
1154 * hit a base type at some point, and we need to be sure
1155 * the next chunk of data is safely available to display
1156 * that type info safely. We cannot rely on the size of
1157 * the current object here because it may be much larger
1158 * than our current buffer (e.g. task_struct is 8k).
1159 * All we want to do here is ensure that we can print the
1160 * next basic type, which we can if either
1161 * - the current type size is within the safe buffer; or
1162 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1165 safe = __btf_show_obj_safe(show, data,
1167 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1171 * We need a new copy to our safe object, either because we haven't
1172 * yet copied and are initializing safe data, or because the data
1173 * we want falls outside the boundaries of the safe object.
1176 size_left = btf_show_obj_size_left(show, data);
1177 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1178 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1179 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1181 if (!show->state.status) {
1182 show->obj.data = data;
1183 safe = show->obj.safe;
1191 * Set the type we are starting to show and return a safe data pointer
1192 * to be used for showing the associated data.
1194 static void *btf_show_start_type(struct btf_show *show,
1195 const struct btf_type *t,
1196 u32 type_id, void *data)
1198 show->state.type = t;
1199 show->state.type_id = type_id;
1200 show->state.name[0] = '\0';
1202 return btf_show_obj_safe(show, t, data);
1205 static void btf_show_end_type(struct btf_show *show)
1207 show->state.type = NULL;
1208 show->state.type_id = 0;
1209 show->state.name[0] = '\0';
1212 static void *btf_show_start_aggr_type(struct btf_show *show,
1213 const struct btf_type *t,
1214 u32 type_id, void *data)
1216 void *safe_data = btf_show_start_type(show, t, type_id, data);
1221 btf_show(show, "%s%s%s", btf_show_indent(show),
1222 btf_show_name(show),
1223 btf_show_newline(show));
1224 show->state.depth++;
1228 static void btf_show_end_aggr_type(struct btf_show *show,
1231 show->state.depth--;
1232 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1233 btf_show_delim(show), btf_show_newline(show));
1234 btf_show_end_type(show);
1237 static void btf_show_start_member(struct btf_show *show,
1238 const struct btf_member *m)
1240 show->state.member = m;
1243 static void btf_show_start_array_member(struct btf_show *show)
1245 show->state.array_member = 1;
1246 btf_show_start_member(show, NULL);
1249 static void btf_show_end_member(struct btf_show *show)
1251 show->state.member = NULL;
1254 static void btf_show_end_array_member(struct btf_show *show)
1256 show->state.array_member = 0;
1257 btf_show_end_member(show);
1260 static void *btf_show_start_array_type(struct btf_show *show,
1261 const struct btf_type *t,
1266 show->state.array_encoding = array_encoding;
1267 show->state.array_terminated = 0;
1268 return btf_show_start_aggr_type(show, t, type_id, data);
1271 static void btf_show_end_array_type(struct btf_show *show)
1273 show->state.array_encoding = 0;
1274 show->state.array_terminated = 0;
1275 btf_show_end_aggr_type(show, "]");
1278 static void *btf_show_start_struct_type(struct btf_show *show,
1279 const struct btf_type *t,
1283 return btf_show_start_aggr_type(show, t, type_id, data);
1286 static void btf_show_end_struct_type(struct btf_show *show)
1288 btf_show_end_aggr_type(show, "}");
1291 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1292 const char *fmt, ...)
1296 va_start(args, fmt);
1297 bpf_verifier_vlog(log, fmt, args);
1301 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1302 const char *fmt, ...)
1304 struct bpf_verifier_log *log = &env->log;
1307 if (!bpf_verifier_log_needed(log))
1310 va_start(args, fmt);
1311 bpf_verifier_vlog(log, fmt, args);
1315 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1316 const struct btf_type *t,
1318 const char *fmt, ...)
1320 struct bpf_verifier_log *log = &env->log;
1321 u8 kind = BTF_INFO_KIND(t->info);
1322 struct btf *btf = env->btf;
1325 if (!bpf_verifier_log_needed(log))
1328 /* btf verifier prints all types it is processing via
1329 * btf_verifier_log_type(..., fmt = NULL).
1330 * Skip those prints for in-kernel BTF verification.
1332 if (log->level == BPF_LOG_KERNEL && !fmt)
1335 __btf_verifier_log(log, "[%u] %s %s%s",
1338 __btf_name_by_offset(btf, t->name_off),
1339 log_details ? " " : "");
1342 btf_type_ops(t)->log_details(env, t);
1345 __btf_verifier_log(log, " ");
1346 va_start(args, fmt);
1347 bpf_verifier_vlog(log, fmt, args);
1351 __btf_verifier_log(log, "\n");
1354 #define btf_verifier_log_type(env, t, ...) \
1355 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1356 #define btf_verifier_log_basic(env, t, ...) \
1357 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1360 static void btf_verifier_log_member(struct btf_verifier_env *env,
1361 const struct btf_type *struct_type,
1362 const struct btf_member *member,
1363 const char *fmt, ...)
1365 struct bpf_verifier_log *log = &env->log;
1366 struct btf *btf = env->btf;
1369 if (!bpf_verifier_log_needed(log))
1372 if (log->level == BPF_LOG_KERNEL && !fmt)
1374 /* The CHECK_META phase already did a btf dump.
1376 * If member is logged again, it must hit an error in
1377 * parsing this member. It is useful to print out which
1378 * struct this member belongs to.
1380 if (env->phase != CHECK_META)
1381 btf_verifier_log_type(env, struct_type, NULL);
1383 if (btf_type_kflag(struct_type))
1384 __btf_verifier_log(log,
1385 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1386 __btf_name_by_offset(btf, member->name_off),
1388 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1389 BTF_MEMBER_BIT_OFFSET(member->offset));
1391 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1392 __btf_name_by_offset(btf, member->name_off),
1393 member->type, member->offset);
1396 __btf_verifier_log(log, " ");
1397 va_start(args, fmt);
1398 bpf_verifier_vlog(log, fmt, args);
1402 __btf_verifier_log(log, "\n");
1406 static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1407 const struct btf_type *datasec_type,
1408 const struct btf_var_secinfo *vsi,
1409 const char *fmt, ...)
1411 struct bpf_verifier_log *log = &env->log;
1414 if (!bpf_verifier_log_needed(log))
1416 if (log->level == BPF_LOG_KERNEL && !fmt)
1418 if (env->phase != CHECK_META)
1419 btf_verifier_log_type(env, datasec_type, NULL);
1421 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1422 vsi->type, vsi->offset, vsi->size);
1424 __btf_verifier_log(log, " ");
1425 va_start(args, fmt);
1426 bpf_verifier_vlog(log, fmt, args);
1430 __btf_verifier_log(log, "\n");
1433 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1436 struct bpf_verifier_log *log = &env->log;
1437 const struct btf *btf = env->btf;
1438 const struct btf_header *hdr;
1440 if (!bpf_verifier_log_needed(log))
1443 if (log->level == BPF_LOG_KERNEL)
1446 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1447 __btf_verifier_log(log, "version: %u\n", hdr->version);
1448 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1449 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1450 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1451 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1452 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1453 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1454 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1457 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1459 struct btf *btf = env->btf;
1461 if (btf->types_size == btf->nr_types) {
1462 /* Expand 'types' array */
1464 struct btf_type **new_types;
1465 u32 expand_by, new_size;
1467 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1468 btf_verifier_log(env, "Exceeded max num of types");
1472 expand_by = max_t(u32, btf->types_size >> 2, 16);
1473 new_size = min_t(u32, BTF_MAX_TYPE,
1474 btf->types_size + expand_by);
1476 new_types = kvcalloc(new_size, sizeof(*new_types),
1477 GFP_KERNEL | __GFP_NOWARN);
1481 if (btf->nr_types == 0) {
1482 if (!btf->base_btf) {
1483 /* lazily init VOID type */
1484 new_types[0] = &btf_void;
1488 memcpy(new_types, btf->types,
1489 sizeof(*btf->types) * btf->nr_types);
1493 btf->types = new_types;
1494 btf->types_size = new_size;
1497 btf->types[btf->nr_types++] = t;
1502 static int btf_alloc_id(struct btf *btf)
1506 idr_preload(GFP_KERNEL);
1507 spin_lock_bh(&btf_idr_lock);
1508 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1511 spin_unlock_bh(&btf_idr_lock);
1514 if (WARN_ON_ONCE(!id))
1517 return id > 0 ? 0 : id;
1520 static void btf_free_id(struct btf *btf)
1522 unsigned long flags;
1525 * In map-in-map, calling map_delete_elem() on outer
1526 * map will call bpf_map_put on the inner map.
1527 * It will then eventually call btf_free_id()
1528 * on the inner map. Some of the map_delete_elem()
1529 * implementation may have irq disabled, so
1530 * we need to use the _irqsave() version instead
1531 * of the _bh() version.
1533 spin_lock_irqsave(&btf_idr_lock, flags);
1534 idr_remove(&btf_idr, btf->id);
1535 spin_unlock_irqrestore(&btf_idr_lock, flags);
1538 static void btf_free(struct btf *btf)
1541 kvfree(btf->resolved_sizes);
1542 kvfree(btf->resolved_ids);
1547 static void btf_free_rcu(struct rcu_head *rcu)
1549 struct btf *btf = container_of(rcu, struct btf, rcu);
1554 void btf_get(struct btf *btf)
1556 refcount_inc(&btf->refcnt);
1559 void btf_put(struct btf *btf)
1561 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1563 call_rcu(&btf->rcu, btf_free_rcu);
1567 static int env_resolve_init(struct btf_verifier_env *env)
1569 struct btf *btf = env->btf;
1570 u32 nr_types = btf->nr_types;
1571 u32 *resolved_sizes = NULL;
1572 u32 *resolved_ids = NULL;
1573 u8 *visit_states = NULL;
1575 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1576 GFP_KERNEL | __GFP_NOWARN);
1577 if (!resolved_sizes)
1580 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1581 GFP_KERNEL | __GFP_NOWARN);
1585 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1586 GFP_KERNEL | __GFP_NOWARN);
1590 btf->resolved_sizes = resolved_sizes;
1591 btf->resolved_ids = resolved_ids;
1592 env->visit_states = visit_states;
1597 kvfree(resolved_sizes);
1598 kvfree(resolved_ids);
1599 kvfree(visit_states);
1603 static void btf_verifier_env_free(struct btf_verifier_env *env)
1605 kvfree(env->visit_states);
1609 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1610 const struct btf_type *next_type)
1612 switch (env->resolve_mode) {
1614 /* int, enum or void is a sink */
1615 return !btf_type_needs_resolve(next_type);
1617 /* int, enum, void, struct, array, func or func_proto is a sink
1620 return !btf_type_is_modifier(next_type) &&
1621 !btf_type_is_ptr(next_type);
1622 case RESOLVE_STRUCT_OR_ARRAY:
1623 /* int, enum, void, ptr, func or func_proto is a sink
1624 * for struct and array
1626 return !btf_type_is_modifier(next_type) &&
1627 !btf_type_is_array(next_type) &&
1628 !btf_type_is_struct(next_type);
1634 static bool env_type_is_resolved(const struct btf_verifier_env *env,
1637 /* base BTF types should be resolved by now */
1638 if (type_id < env->btf->start_id)
1641 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1644 static int env_stack_push(struct btf_verifier_env *env,
1645 const struct btf_type *t, u32 type_id)
1647 const struct btf *btf = env->btf;
1648 struct resolve_vertex *v;
1650 if (env->top_stack == MAX_RESOLVE_DEPTH)
1653 if (type_id < btf->start_id
1654 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1657 env->visit_states[type_id - btf->start_id] = VISITED;
1659 v = &env->stack[env->top_stack++];
1661 v->type_id = type_id;
1664 if (env->resolve_mode == RESOLVE_TBD) {
1665 if (btf_type_is_ptr(t))
1666 env->resolve_mode = RESOLVE_PTR;
1667 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1668 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1674 static void env_stack_set_next_member(struct btf_verifier_env *env,
1677 env->stack[env->top_stack - 1].next_member = next_member;
1680 static void env_stack_pop_resolved(struct btf_verifier_env *env,
1681 u32 resolved_type_id,
1684 u32 type_id = env->stack[--(env->top_stack)].type_id;
1685 struct btf *btf = env->btf;
1687 type_id -= btf->start_id; /* adjust to local type id */
1688 btf->resolved_sizes[type_id] = resolved_size;
1689 btf->resolved_ids[type_id] = resolved_type_id;
1690 env->visit_states[type_id] = RESOLVED;
1693 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1695 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1698 /* Resolve the size of a passed-in "type"
1700 * type: is an array (e.g. u32 array[x][y])
1701 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1702 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1703 * corresponds to the return type.
1705 * *elem_id: id of u32
1706 * *total_nelems: (x * y). Hence, individual elem size is
1707 * (*type_size / *total_nelems)
1708 * *type_id: id of type if it's changed within the function, 0 if not
1710 * type: is not an array (e.g. const struct X)
1711 * return type: type "struct X"
1712 * *type_size: sizeof(struct X)
1713 * *elem_type: same as return type ("struct X")
1716 * *type_id: id of type if it's changed within the function, 0 if not
1718 static const struct btf_type *
1719 __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1720 u32 *type_size, const struct btf_type **elem_type,
1721 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1723 const struct btf_type *array_type = NULL;
1724 const struct btf_array *array = NULL;
1725 u32 i, size, nelems = 1, id = 0;
1727 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1728 switch (BTF_INFO_KIND(type->info)) {
1729 /* type->size can be used */
1731 case BTF_KIND_STRUCT:
1732 case BTF_KIND_UNION:
1734 case BTF_KIND_FLOAT:
1739 size = sizeof(void *);
1743 case BTF_KIND_TYPEDEF:
1744 case BTF_KIND_VOLATILE:
1745 case BTF_KIND_CONST:
1746 case BTF_KIND_RESTRICT:
1747 case BTF_KIND_TYPE_TAG:
1749 type = btf_type_by_id(btf, type->type);
1752 case BTF_KIND_ARRAY:
1755 array = btf_type_array(type);
1756 if (nelems && array->nelems > U32_MAX / nelems)
1757 return ERR_PTR(-EINVAL);
1758 nelems *= array->nelems;
1759 type = btf_type_by_id(btf, array->type);
1762 /* type without size */
1764 return ERR_PTR(-EINVAL);
1768 return ERR_PTR(-EINVAL);
1771 if (nelems && size > U32_MAX / nelems)
1772 return ERR_PTR(-EINVAL);
1774 *type_size = nelems * size;
1776 *total_nelems = nelems;
1780 *elem_id = array ? array->type : 0;
1784 return array_type ? : type;
1787 const struct btf_type *
1788 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1791 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1794 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1796 while (type_id < btf->start_id)
1797 btf = btf->base_btf;
1799 return btf->resolved_ids[type_id - btf->start_id];
1802 /* The input param "type_id" must point to a needs_resolve type */
1803 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1806 *type_id = btf_resolved_type_id(btf, *type_id);
1807 return btf_type_by_id(btf, *type_id);
1810 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1812 while (type_id < btf->start_id)
1813 btf = btf->base_btf;
1815 return btf->resolved_sizes[type_id - btf->start_id];
1818 const struct btf_type *btf_type_id_size(const struct btf *btf,
1819 u32 *type_id, u32 *ret_size)
1821 const struct btf_type *size_type;
1822 u32 size_type_id = *type_id;
1825 size_type = btf_type_by_id(btf, size_type_id);
1826 if (btf_type_nosize_or_null(size_type))
1829 if (btf_type_has_size(size_type)) {
1830 size = size_type->size;
1831 } else if (btf_type_is_array(size_type)) {
1832 size = btf_resolved_type_size(btf, size_type_id);
1833 } else if (btf_type_is_ptr(size_type)) {
1834 size = sizeof(void *);
1836 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1837 !btf_type_is_var(size_type)))
1840 size_type_id = btf_resolved_type_id(btf, size_type_id);
1841 size_type = btf_type_by_id(btf, size_type_id);
1842 if (btf_type_nosize_or_null(size_type))
1844 else if (btf_type_has_size(size_type))
1845 size = size_type->size;
1846 else if (btf_type_is_array(size_type))
1847 size = btf_resolved_type_size(btf, size_type_id);
1848 else if (btf_type_is_ptr(size_type))
1849 size = sizeof(void *);
1854 *type_id = size_type_id;
1861 static int btf_df_check_member(struct btf_verifier_env *env,
1862 const struct btf_type *struct_type,
1863 const struct btf_member *member,
1864 const struct btf_type *member_type)
1866 btf_verifier_log_basic(env, struct_type,
1867 "Unsupported check_member");
1871 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1872 const struct btf_type *struct_type,
1873 const struct btf_member *member,
1874 const struct btf_type *member_type)
1876 btf_verifier_log_basic(env, struct_type,
1877 "Unsupported check_kflag_member");
1881 /* Used for ptr, array struct/union and float type members.
1882 * int, enum and modifier types have their specific callback functions.
1884 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1885 const struct btf_type *struct_type,
1886 const struct btf_member *member,
1887 const struct btf_type *member_type)
1889 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1890 btf_verifier_log_member(env, struct_type, member,
1891 "Invalid member bitfield_size");
1895 /* bitfield size is 0, so member->offset represents bit offset only.
1896 * It is safe to call non kflag check_member variants.
1898 return btf_type_ops(member_type)->check_member(env, struct_type,
1903 static int btf_df_resolve(struct btf_verifier_env *env,
1904 const struct resolve_vertex *v)
1906 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1910 static void btf_df_show(const struct btf *btf, const struct btf_type *t,
1911 u32 type_id, void *data, u8 bits_offsets,
1912 struct btf_show *show)
1914 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1917 static int btf_int_check_member(struct btf_verifier_env *env,
1918 const struct btf_type *struct_type,
1919 const struct btf_member *member,
1920 const struct btf_type *member_type)
1922 u32 int_data = btf_type_int(member_type);
1923 u32 struct_bits_off = member->offset;
1924 u32 struct_size = struct_type->size;
1928 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1929 btf_verifier_log_member(env, struct_type, member,
1930 "bits_offset exceeds U32_MAX");
1934 struct_bits_off += BTF_INT_OFFSET(int_data);
1935 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1936 nr_copy_bits = BTF_INT_BITS(int_data) +
1937 BITS_PER_BYTE_MASKED(struct_bits_off);
1939 if (nr_copy_bits > BITS_PER_U128) {
1940 btf_verifier_log_member(env, struct_type, member,
1941 "nr_copy_bits exceeds 128");
1945 if (struct_size < bytes_offset ||
1946 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1947 btf_verifier_log_member(env, struct_type, member,
1948 "Member exceeds struct_size");
1955 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1956 const struct btf_type *struct_type,
1957 const struct btf_member *member,
1958 const struct btf_type *member_type)
1960 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1961 u32 int_data = btf_type_int(member_type);
1962 u32 struct_size = struct_type->size;
1965 /* a regular int type is required for the kflag int member */
1966 if (!btf_type_int_is_regular(member_type)) {
1967 btf_verifier_log_member(env, struct_type, member,
1968 "Invalid member base type");
1972 /* check sanity of bitfield size */
1973 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
1974 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
1975 nr_int_data_bits = BTF_INT_BITS(int_data);
1977 /* Not a bitfield member, member offset must be at byte
1980 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
1981 btf_verifier_log_member(env, struct_type, member,
1982 "Invalid member offset");
1986 nr_bits = nr_int_data_bits;
1987 } else if (nr_bits > nr_int_data_bits) {
1988 btf_verifier_log_member(env, struct_type, member,
1989 "Invalid member bitfield_size");
1993 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1994 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
1995 if (nr_copy_bits > BITS_PER_U128) {
1996 btf_verifier_log_member(env, struct_type, member,
1997 "nr_copy_bits exceeds 128");
2001 if (struct_size < bytes_offset ||
2002 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2003 btf_verifier_log_member(env, struct_type, member,
2004 "Member exceeds struct_size");
2011 static s32 btf_int_check_meta(struct btf_verifier_env *env,
2012 const struct btf_type *t,
2015 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2018 if (meta_left < meta_needed) {
2019 btf_verifier_log_basic(env, t,
2020 "meta_left:%u meta_needed:%u",
2021 meta_left, meta_needed);
2025 if (btf_type_vlen(t)) {
2026 btf_verifier_log_type(env, t, "vlen != 0");
2030 if (btf_type_kflag(t)) {
2031 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2035 int_data = btf_type_int(t);
2036 if (int_data & ~BTF_INT_MASK) {
2037 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2042 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2044 if (nr_bits > BITS_PER_U128) {
2045 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2050 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2051 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2056 * Only one of the encoding bits is allowed and it
2057 * should be sufficient for the pretty print purpose (i.e. decoding).
2058 * Multiple bits can be allowed later if it is found
2059 * to be insufficient.
2061 encoding = BTF_INT_ENCODING(int_data);
2063 encoding != BTF_INT_SIGNED &&
2064 encoding != BTF_INT_CHAR &&
2065 encoding != BTF_INT_BOOL) {
2066 btf_verifier_log_type(env, t, "Unsupported encoding");
2070 btf_verifier_log_type(env, t, NULL);
2075 static void btf_int_log(struct btf_verifier_env *env,
2076 const struct btf_type *t)
2078 int int_data = btf_type_int(t);
2080 btf_verifier_log(env,
2081 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2082 t->size, BTF_INT_OFFSET(int_data),
2083 BTF_INT_BITS(int_data),
2084 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2087 static void btf_int128_print(struct btf_show *show, void *data)
2089 /* data points to a __int128 number.
2091 * int128_num = *(__int128 *)data;
2092 * The below formulas shows what upper_num and lower_num represents:
2093 * upper_num = int128_num >> 64;
2094 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2096 u64 upper_num, lower_num;
2098 #ifdef __BIG_ENDIAN_BITFIELD
2099 upper_num = *(u64 *)data;
2100 lower_num = *(u64 *)(data + 8);
2102 upper_num = *(u64 *)(data + 8);
2103 lower_num = *(u64 *)data;
2106 btf_show_type_value(show, "0x%llx", lower_num);
2108 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2112 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2113 u16 right_shift_bits)
2115 u64 upper_num, lower_num;
2117 #ifdef __BIG_ENDIAN_BITFIELD
2118 upper_num = print_num[0];
2119 lower_num = print_num[1];
2121 upper_num = print_num[1];
2122 lower_num = print_num[0];
2125 /* shake out un-needed bits by shift/or operations */
2126 if (left_shift_bits >= 64) {
2127 upper_num = lower_num << (left_shift_bits - 64);
2130 upper_num = (upper_num << left_shift_bits) |
2131 (lower_num >> (64 - left_shift_bits));
2132 lower_num = lower_num << left_shift_bits;
2135 if (right_shift_bits >= 64) {
2136 lower_num = upper_num >> (right_shift_bits - 64);
2139 lower_num = (lower_num >> right_shift_bits) |
2140 (upper_num << (64 - right_shift_bits));
2141 upper_num = upper_num >> right_shift_bits;
2144 #ifdef __BIG_ENDIAN_BITFIELD
2145 print_num[0] = upper_num;
2146 print_num[1] = lower_num;
2148 print_num[0] = lower_num;
2149 print_num[1] = upper_num;
2153 static void btf_bitfield_show(void *data, u8 bits_offset,
2154 u8 nr_bits, struct btf_show *show)
2156 u16 left_shift_bits, right_shift_bits;
2159 u64 print_num[2] = {};
2161 nr_copy_bits = nr_bits + bits_offset;
2162 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2164 memcpy(print_num, data, nr_copy_bytes);
2166 #ifdef __BIG_ENDIAN_BITFIELD
2167 left_shift_bits = bits_offset;
2169 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2171 right_shift_bits = BITS_PER_U128 - nr_bits;
2173 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2174 btf_int128_print(show, print_num);
2178 static void btf_int_bits_show(const struct btf *btf,
2179 const struct btf_type *t,
2180 void *data, u8 bits_offset,
2181 struct btf_show *show)
2183 u32 int_data = btf_type_int(t);
2184 u8 nr_bits = BTF_INT_BITS(int_data);
2185 u8 total_bits_offset;
2188 * bits_offset is at most 7.
2189 * BTF_INT_OFFSET() cannot exceed 128 bits.
2191 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2192 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2193 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2194 btf_bitfield_show(data, bits_offset, nr_bits, show);
2197 static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2198 u32 type_id, void *data, u8 bits_offset,
2199 struct btf_show *show)
2201 u32 int_data = btf_type_int(t);
2202 u8 encoding = BTF_INT_ENCODING(int_data);
2203 bool sign = encoding & BTF_INT_SIGNED;
2204 u8 nr_bits = BTF_INT_BITS(int_data);
2207 safe_data = btf_show_start_type(show, t, type_id, data);
2211 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2212 BITS_PER_BYTE_MASKED(nr_bits)) {
2213 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2219 btf_int128_print(show, safe_data);
2223 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2225 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2229 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2231 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2235 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2237 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2240 if (show->state.array_encoding == BTF_INT_CHAR) {
2241 /* check for null terminator */
2242 if (show->state.array_terminated)
2244 if (*(char *)data == '\0') {
2245 show->state.array_terminated = 1;
2248 if (isprint(*(char *)data)) {
2249 btf_show_type_value(show, "'%c'",
2250 *(char *)safe_data);
2255 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2257 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2260 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2264 btf_show_end_type(show);
2267 static const struct btf_kind_operations int_ops = {
2268 .check_meta = btf_int_check_meta,
2269 .resolve = btf_df_resolve,
2270 .check_member = btf_int_check_member,
2271 .check_kflag_member = btf_int_check_kflag_member,
2272 .log_details = btf_int_log,
2273 .show = btf_int_show,
2276 static int btf_modifier_check_member(struct btf_verifier_env *env,
2277 const struct btf_type *struct_type,
2278 const struct btf_member *member,
2279 const struct btf_type *member_type)
2281 const struct btf_type *resolved_type;
2282 u32 resolved_type_id = member->type;
2283 struct btf_member resolved_member;
2284 struct btf *btf = env->btf;
2286 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2287 if (!resolved_type) {
2288 btf_verifier_log_member(env, struct_type, member,
2293 resolved_member = *member;
2294 resolved_member.type = resolved_type_id;
2296 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2301 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2302 const struct btf_type *struct_type,
2303 const struct btf_member *member,
2304 const struct btf_type *member_type)
2306 const struct btf_type *resolved_type;
2307 u32 resolved_type_id = member->type;
2308 struct btf_member resolved_member;
2309 struct btf *btf = env->btf;
2311 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2312 if (!resolved_type) {
2313 btf_verifier_log_member(env, struct_type, member,
2318 resolved_member = *member;
2319 resolved_member.type = resolved_type_id;
2321 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2326 static int btf_ptr_check_member(struct btf_verifier_env *env,
2327 const struct btf_type *struct_type,
2328 const struct btf_member *member,
2329 const struct btf_type *member_type)
2331 u32 struct_size, struct_bits_off, bytes_offset;
2333 struct_size = struct_type->size;
2334 struct_bits_off = member->offset;
2335 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2337 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2338 btf_verifier_log_member(env, struct_type, member,
2339 "Member is not byte aligned");
2343 if (struct_size - bytes_offset < sizeof(void *)) {
2344 btf_verifier_log_member(env, struct_type, member,
2345 "Member exceeds struct_size");
2352 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2353 const struct btf_type *t,
2358 if (btf_type_vlen(t)) {
2359 btf_verifier_log_type(env, t, "vlen != 0");
2363 if (btf_type_kflag(t)) {
2364 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2368 if (!BTF_TYPE_ID_VALID(t->type)) {
2369 btf_verifier_log_type(env, t, "Invalid type_id");
2373 /* typedef/type_tag type must have a valid name, and other ref types,
2374 * volatile, const, restrict, should have a null name.
2376 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2378 !btf_name_valid_identifier(env->btf, t->name_off)) {
2379 btf_verifier_log_type(env, t, "Invalid name");
2382 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2383 value = btf_name_by_offset(env->btf, t->name_off);
2384 if (!value || !value[0]) {
2385 btf_verifier_log_type(env, t, "Invalid name");
2390 btf_verifier_log_type(env, t, "Invalid name");
2395 btf_verifier_log_type(env, t, NULL);
2400 static int btf_modifier_resolve(struct btf_verifier_env *env,
2401 const struct resolve_vertex *v)
2403 const struct btf_type *t = v->t;
2404 const struct btf_type *next_type;
2405 u32 next_type_id = t->type;
2406 struct btf *btf = env->btf;
2408 next_type = btf_type_by_id(btf, next_type_id);
2409 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2410 btf_verifier_log_type(env, v->t, "Invalid type_id");
2414 if (!env_type_is_resolve_sink(env, next_type) &&
2415 !env_type_is_resolved(env, next_type_id))
2416 return env_stack_push(env, next_type, next_type_id);
2418 /* Figure out the resolved next_type_id with size.
2419 * They will be stored in the current modifier's
2420 * resolved_ids and resolved_sizes such that it can
2421 * save us a few type-following when we use it later (e.g. in
2424 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2425 if (env_type_is_resolved(env, next_type_id))
2426 next_type = btf_type_id_resolve(btf, &next_type_id);
2428 /* "typedef void new_void", "const void"...etc */
2429 if (!btf_type_is_void(next_type) &&
2430 !btf_type_is_fwd(next_type) &&
2431 !btf_type_is_func_proto(next_type)) {
2432 btf_verifier_log_type(env, v->t, "Invalid type_id");
2437 env_stack_pop_resolved(env, next_type_id, 0);
2442 static int btf_var_resolve(struct btf_verifier_env *env,
2443 const struct resolve_vertex *v)
2445 const struct btf_type *next_type;
2446 const struct btf_type *t = v->t;
2447 u32 next_type_id = t->type;
2448 struct btf *btf = env->btf;
2450 next_type = btf_type_by_id(btf, next_type_id);
2451 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2452 btf_verifier_log_type(env, v->t, "Invalid type_id");
2456 if (!env_type_is_resolve_sink(env, next_type) &&
2457 !env_type_is_resolved(env, next_type_id))
2458 return env_stack_push(env, next_type, next_type_id);
2460 if (btf_type_is_modifier(next_type)) {
2461 const struct btf_type *resolved_type;
2462 u32 resolved_type_id;
2464 resolved_type_id = next_type_id;
2465 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2467 if (btf_type_is_ptr(resolved_type) &&
2468 !env_type_is_resolve_sink(env, resolved_type) &&
2469 !env_type_is_resolved(env, resolved_type_id))
2470 return env_stack_push(env, resolved_type,
2474 /* We must resolve to something concrete at this point, no
2475 * forward types or similar that would resolve to size of
2478 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2479 btf_verifier_log_type(env, v->t, "Invalid type_id");
2483 env_stack_pop_resolved(env, next_type_id, 0);
2488 static int btf_ptr_resolve(struct btf_verifier_env *env,
2489 const struct resolve_vertex *v)
2491 const struct btf_type *next_type;
2492 const struct btf_type *t = v->t;
2493 u32 next_type_id = t->type;
2494 struct btf *btf = env->btf;
2496 next_type = btf_type_by_id(btf, next_type_id);
2497 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2498 btf_verifier_log_type(env, v->t, "Invalid type_id");
2502 if (!env_type_is_resolve_sink(env, next_type) &&
2503 !env_type_is_resolved(env, next_type_id))
2504 return env_stack_push(env, next_type, next_type_id);
2506 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2507 * the modifier may have stopped resolving when it was resolved
2508 * to a ptr (last-resolved-ptr).
2510 * We now need to continue from the last-resolved-ptr to
2511 * ensure the last-resolved-ptr will not referring back to
2512 * the currenct ptr (t).
2514 if (btf_type_is_modifier(next_type)) {
2515 const struct btf_type *resolved_type;
2516 u32 resolved_type_id;
2518 resolved_type_id = next_type_id;
2519 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2521 if (btf_type_is_ptr(resolved_type) &&
2522 !env_type_is_resolve_sink(env, resolved_type) &&
2523 !env_type_is_resolved(env, resolved_type_id))
2524 return env_stack_push(env, resolved_type,
2528 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2529 if (env_type_is_resolved(env, next_type_id))
2530 next_type = btf_type_id_resolve(btf, &next_type_id);
2532 if (!btf_type_is_void(next_type) &&
2533 !btf_type_is_fwd(next_type) &&
2534 !btf_type_is_func_proto(next_type)) {
2535 btf_verifier_log_type(env, v->t, "Invalid type_id");
2540 env_stack_pop_resolved(env, next_type_id, 0);
2545 static void btf_modifier_show(const struct btf *btf,
2546 const struct btf_type *t,
2547 u32 type_id, void *data,
2548 u8 bits_offset, struct btf_show *show)
2550 if (btf->resolved_ids)
2551 t = btf_type_id_resolve(btf, &type_id);
2553 t = btf_type_skip_modifiers(btf, type_id, NULL);
2555 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2558 static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2559 u32 type_id, void *data, u8 bits_offset,
2560 struct btf_show *show)
2562 t = btf_type_id_resolve(btf, &type_id);
2564 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2567 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2568 u32 type_id, void *data, u8 bits_offset,
2569 struct btf_show *show)
2573 safe_data = btf_show_start_type(show, t, type_id, data);
2577 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2578 if (show->flags & BTF_SHOW_PTR_RAW)
2579 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2581 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2582 btf_show_end_type(show);
2585 static void btf_ref_type_log(struct btf_verifier_env *env,
2586 const struct btf_type *t)
2588 btf_verifier_log(env, "type_id=%u", t->type);
2591 static struct btf_kind_operations modifier_ops = {
2592 .check_meta = btf_ref_type_check_meta,
2593 .resolve = btf_modifier_resolve,
2594 .check_member = btf_modifier_check_member,
2595 .check_kflag_member = btf_modifier_check_kflag_member,
2596 .log_details = btf_ref_type_log,
2597 .show = btf_modifier_show,
2600 static struct btf_kind_operations ptr_ops = {
2601 .check_meta = btf_ref_type_check_meta,
2602 .resolve = btf_ptr_resolve,
2603 .check_member = btf_ptr_check_member,
2604 .check_kflag_member = btf_generic_check_kflag_member,
2605 .log_details = btf_ref_type_log,
2606 .show = btf_ptr_show,
2609 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2610 const struct btf_type *t,
2613 if (btf_type_vlen(t)) {
2614 btf_verifier_log_type(env, t, "vlen != 0");
2619 btf_verifier_log_type(env, t, "type != 0");
2623 /* fwd type must have a valid name */
2625 !btf_name_valid_identifier(env->btf, t->name_off)) {
2626 btf_verifier_log_type(env, t, "Invalid name");
2630 btf_verifier_log_type(env, t, NULL);
2635 static void btf_fwd_type_log(struct btf_verifier_env *env,
2636 const struct btf_type *t)
2638 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2641 static struct btf_kind_operations fwd_ops = {
2642 .check_meta = btf_fwd_check_meta,
2643 .resolve = btf_df_resolve,
2644 .check_member = btf_df_check_member,
2645 .check_kflag_member = btf_df_check_kflag_member,
2646 .log_details = btf_fwd_type_log,
2647 .show = btf_df_show,
2650 static int btf_array_check_member(struct btf_verifier_env *env,
2651 const struct btf_type *struct_type,
2652 const struct btf_member *member,
2653 const struct btf_type *member_type)
2655 u32 struct_bits_off = member->offset;
2656 u32 struct_size, bytes_offset;
2657 u32 array_type_id, array_size;
2658 struct btf *btf = env->btf;
2660 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2661 btf_verifier_log_member(env, struct_type, member,
2662 "Member is not byte aligned");
2666 array_type_id = member->type;
2667 btf_type_id_size(btf, &array_type_id, &array_size);
2668 struct_size = struct_type->size;
2669 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2670 if (struct_size - bytes_offset < array_size) {
2671 btf_verifier_log_member(env, struct_type, member,
2672 "Member exceeds struct_size");
2679 static s32 btf_array_check_meta(struct btf_verifier_env *env,
2680 const struct btf_type *t,
2683 const struct btf_array *array = btf_type_array(t);
2684 u32 meta_needed = sizeof(*array);
2686 if (meta_left < meta_needed) {
2687 btf_verifier_log_basic(env, t,
2688 "meta_left:%u meta_needed:%u",
2689 meta_left, meta_needed);
2693 /* array type should not have a name */
2695 btf_verifier_log_type(env, t, "Invalid name");
2699 if (btf_type_vlen(t)) {
2700 btf_verifier_log_type(env, t, "vlen != 0");
2704 if (btf_type_kflag(t)) {
2705 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2710 btf_verifier_log_type(env, t, "size != 0");
2714 /* Array elem type and index type cannot be in type void,
2715 * so !array->type and !array->index_type are not allowed.
2717 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2718 btf_verifier_log_type(env, t, "Invalid elem");
2722 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2723 btf_verifier_log_type(env, t, "Invalid index");
2727 btf_verifier_log_type(env, t, NULL);
2732 static int btf_array_resolve(struct btf_verifier_env *env,
2733 const struct resolve_vertex *v)
2735 const struct btf_array *array = btf_type_array(v->t);
2736 const struct btf_type *elem_type, *index_type;
2737 u32 elem_type_id, index_type_id;
2738 struct btf *btf = env->btf;
2741 /* Check array->index_type */
2742 index_type_id = array->index_type;
2743 index_type = btf_type_by_id(btf, index_type_id);
2744 if (btf_type_nosize_or_null(index_type) ||
2745 btf_type_is_resolve_source_only(index_type)) {
2746 btf_verifier_log_type(env, v->t, "Invalid index");
2750 if (!env_type_is_resolve_sink(env, index_type) &&
2751 !env_type_is_resolved(env, index_type_id))
2752 return env_stack_push(env, index_type, index_type_id);
2754 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2755 if (!index_type || !btf_type_is_int(index_type) ||
2756 !btf_type_int_is_regular(index_type)) {
2757 btf_verifier_log_type(env, v->t, "Invalid index");
2761 /* Check array->type */
2762 elem_type_id = array->type;
2763 elem_type = btf_type_by_id(btf, elem_type_id);
2764 if (btf_type_nosize_or_null(elem_type) ||
2765 btf_type_is_resolve_source_only(elem_type)) {
2766 btf_verifier_log_type(env, v->t,
2771 if (!env_type_is_resolve_sink(env, elem_type) &&
2772 !env_type_is_resolved(env, elem_type_id))
2773 return env_stack_push(env, elem_type, elem_type_id);
2775 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2777 btf_verifier_log_type(env, v->t, "Invalid elem");
2781 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2782 btf_verifier_log_type(env, v->t, "Invalid array of int");
2786 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2787 btf_verifier_log_type(env, v->t,
2788 "Array size overflows U32_MAX");
2792 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2797 static void btf_array_log(struct btf_verifier_env *env,
2798 const struct btf_type *t)
2800 const struct btf_array *array = btf_type_array(t);
2802 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2803 array->type, array->index_type, array->nelems);
2806 static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2807 u32 type_id, void *data, u8 bits_offset,
2808 struct btf_show *show)
2810 const struct btf_array *array = btf_type_array(t);
2811 const struct btf_kind_operations *elem_ops;
2812 const struct btf_type *elem_type;
2813 u32 i, elem_size = 0, elem_type_id;
2816 elem_type_id = array->type;
2817 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2818 if (elem_type && btf_type_has_size(elem_type))
2819 elem_size = elem_type->size;
2821 if (elem_type && btf_type_is_int(elem_type)) {
2822 u32 int_type = btf_type_int(elem_type);
2824 encoding = BTF_INT_ENCODING(int_type);
2827 * BTF_INT_CHAR encoding never seems to be set for
2828 * char arrays, so if size is 1 and element is
2829 * printable as a char, we'll do that.
2832 encoding = BTF_INT_CHAR;
2835 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2840 elem_ops = btf_type_ops(elem_type);
2842 for (i = 0; i < array->nelems; i++) {
2844 btf_show_start_array_member(show);
2846 elem_ops->show(btf, elem_type, elem_type_id, data,
2850 btf_show_end_array_member(show);
2852 if (show->state.array_terminated)
2856 btf_show_end_array_type(show);
2859 static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2860 u32 type_id, void *data, u8 bits_offset,
2861 struct btf_show *show)
2863 const struct btf_member *m = show->state.member;
2866 * First check if any members would be shown (are non-zero).
2867 * See comments above "struct btf_show" definition for more
2868 * details on how this works at a high-level.
2870 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2871 if (!show->state.depth_check) {
2872 show->state.depth_check = show->state.depth + 1;
2873 show->state.depth_to_show = 0;
2875 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2876 show->state.member = m;
2878 if (show->state.depth_check != show->state.depth + 1)
2880 show->state.depth_check = 0;
2882 if (show->state.depth_to_show <= show->state.depth)
2885 * Reaching here indicates we have recursed and found
2886 * non-zero array member(s).
2889 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2892 static struct btf_kind_operations array_ops = {
2893 .check_meta = btf_array_check_meta,
2894 .resolve = btf_array_resolve,
2895 .check_member = btf_array_check_member,
2896 .check_kflag_member = btf_generic_check_kflag_member,
2897 .log_details = btf_array_log,
2898 .show = btf_array_show,
2901 static int btf_struct_check_member(struct btf_verifier_env *env,
2902 const struct btf_type *struct_type,
2903 const struct btf_member *member,
2904 const struct btf_type *member_type)
2906 u32 struct_bits_off = member->offset;
2907 u32 struct_size, bytes_offset;
2909 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2910 btf_verifier_log_member(env, struct_type, member,
2911 "Member is not byte aligned");
2915 struct_size = struct_type->size;
2916 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2917 if (struct_size - bytes_offset < member_type->size) {
2918 btf_verifier_log_member(env, struct_type, member,
2919 "Member exceeds struct_size");
2926 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
2927 const struct btf_type *t,
2930 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
2931 const struct btf_member *member;
2932 u32 meta_needed, last_offset;
2933 struct btf *btf = env->btf;
2934 u32 struct_size = t->size;
2938 meta_needed = btf_type_vlen(t) * sizeof(*member);
2939 if (meta_left < meta_needed) {
2940 btf_verifier_log_basic(env, t,
2941 "meta_left:%u meta_needed:%u",
2942 meta_left, meta_needed);
2946 /* struct type either no name or a valid one */
2948 !btf_name_valid_identifier(env->btf, t->name_off)) {
2949 btf_verifier_log_type(env, t, "Invalid name");
2953 btf_verifier_log_type(env, t, NULL);
2956 for_each_member(i, t, member) {
2957 if (!btf_name_offset_valid(btf, member->name_off)) {
2958 btf_verifier_log_member(env, t, member,
2959 "Invalid member name_offset:%u",
2964 /* struct member either no name or a valid one */
2965 if (member->name_off &&
2966 !btf_name_valid_identifier(btf, member->name_off)) {
2967 btf_verifier_log_member(env, t, member, "Invalid name");
2970 /* A member cannot be in type void */
2971 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
2972 btf_verifier_log_member(env, t, member,
2977 offset = __btf_member_bit_offset(t, member);
2978 if (is_union && offset) {
2979 btf_verifier_log_member(env, t, member,
2980 "Invalid member bits_offset");
2985 * ">" instead of ">=" because the last member could be
2988 if (last_offset > offset) {
2989 btf_verifier_log_member(env, t, member,
2990 "Invalid member bits_offset");
2994 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
2995 btf_verifier_log_member(env, t, member,
2996 "Member bits_offset exceeds its struct size");
3000 btf_verifier_log_member(env, t, member, NULL);
3001 last_offset = offset;
3007 static int btf_struct_resolve(struct btf_verifier_env *env,
3008 const struct resolve_vertex *v)
3010 const struct btf_member *member;
3014 /* Before continue resolving the next_member,
3015 * ensure the last member is indeed resolved to a
3016 * type with size info.
3018 if (v->next_member) {
3019 const struct btf_type *last_member_type;
3020 const struct btf_member *last_member;
3021 u16 last_member_type_id;
3023 last_member = btf_type_member(v->t) + v->next_member - 1;
3024 last_member_type_id = last_member->type;
3025 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3026 last_member_type_id)))
3029 last_member_type = btf_type_by_id(env->btf,
3030 last_member_type_id);
3031 if (btf_type_kflag(v->t))
3032 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3036 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3043 for_each_member_from(i, v->next_member, v->t, member) {
3044 u32 member_type_id = member->type;
3045 const struct btf_type *member_type = btf_type_by_id(env->btf,
3048 if (btf_type_nosize_or_null(member_type) ||
3049 btf_type_is_resolve_source_only(member_type)) {
3050 btf_verifier_log_member(env, v->t, member,
3055 if (!env_type_is_resolve_sink(env, member_type) &&
3056 !env_type_is_resolved(env, member_type_id)) {
3057 env_stack_set_next_member(env, i + 1);
3058 return env_stack_push(env, member_type, member_type_id);
3061 if (btf_type_kflag(v->t))
3062 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3066 err = btf_type_ops(member_type)->check_member(env, v->t,
3073 env_stack_pop_resolved(env, 0, 0);
3078 static void btf_struct_log(struct btf_verifier_env *env,
3079 const struct btf_type *t)
3081 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3084 static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t,
3085 const char *name, int sz, int align)
3087 const struct btf_member *member;
3088 u32 i, off = -ENOENT;
3090 for_each_member(i, t, member) {
3091 const struct btf_type *member_type = btf_type_by_id(btf,
3093 if (!__btf_type_is_struct(member_type))
3095 if (member_type->size != sz)
3097 if (strcmp(__btf_name_by_offset(btf, member_type->name_off), name))
3100 /* only one such field is allowed */
3102 off = __btf_member_bit_offset(t, member);
3104 /* valid C code cannot generate such BTF */
3113 static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3114 const char *name, int sz, int align)
3116 const struct btf_var_secinfo *vsi;
3117 u32 i, off = -ENOENT;
3119 for_each_vsi(i, t, vsi) {
3120 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3121 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3123 if (!__btf_type_is_struct(var_type))
3125 if (var_type->size != sz)
3127 if (vsi->size != sz)
3129 if (strcmp(__btf_name_by_offset(btf, var_type->name_off), name))
3132 /* only one such field is allowed */
3141 static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3142 const char *name, int sz, int align)
3145 if (__btf_type_is_struct(t))
3146 return btf_find_struct_field(btf, t, name, sz, align);
3147 else if (btf_type_is_datasec(t))
3148 return btf_find_datasec_var(btf, t, name, sz, align);
3152 /* find 'struct bpf_spin_lock' in map value.
3153 * return >= 0 offset if found
3154 * and < 0 in case of error
3156 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
3158 return btf_find_field(btf, t, "bpf_spin_lock",
3159 sizeof(struct bpf_spin_lock),
3160 __alignof__(struct bpf_spin_lock));
3163 int btf_find_timer(const struct btf *btf, const struct btf_type *t)
3165 return btf_find_field(btf, t, "bpf_timer",
3166 sizeof(struct bpf_timer),
3167 __alignof__(struct bpf_timer));
3170 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3171 u32 type_id, void *data, u8 bits_offset,
3172 struct btf_show *show)
3174 const struct btf_member *member;
3178 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3182 for_each_member(i, t, member) {
3183 const struct btf_type *member_type = btf_type_by_id(btf,
3185 const struct btf_kind_operations *ops;
3186 u32 member_offset, bitfield_size;
3190 btf_show_start_member(show, member);
3192 member_offset = __btf_member_bit_offset(t, member);
3193 bitfield_size = __btf_member_bitfield_size(t, member);
3194 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3195 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3196 if (bitfield_size) {
3197 safe_data = btf_show_start_type(show, member_type,
3199 data + bytes_offset);
3201 btf_bitfield_show(safe_data,
3203 bitfield_size, show);
3204 btf_show_end_type(show);
3206 ops = btf_type_ops(member_type);
3207 ops->show(btf, member_type, member->type,
3208 data + bytes_offset, bits8_offset, show);
3211 btf_show_end_member(show);
3214 btf_show_end_struct_type(show);
3217 static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3218 u32 type_id, void *data, u8 bits_offset,
3219 struct btf_show *show)
3221 const struct btf_member *m = show->state.member;
3224 * First check if any members would be shown (are non-zero).
3225 * See comments above "struct btf_show" definition for more
3226 * details on how this works at a high-level.
3228 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3229 if (!show->state.depth_check) {
3230 show->state.depth_check = show->state.depth + 1;
3231 show->state.depth_to_show = 0;
3233 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3234 /* Restore saved member data here */
3235 show->state.member = m;
3236 if (show->state.depth_check != show->state.depth + 1)
3238 show->state.depth_check = 0;
3240 if (show->state.depth_to_show <= show->state.depth)
3243 * Reaching here indicates we have recursed and found
3244 * non-zero child values.
3248 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3251 static struct btf_kind_operations struct_ops = {
3252 .check_meta = btf_struct_check_meta,
3253 .resolve = btf_struct_resolve,
3254 .check_member = btf_struct_check_member,
3255 .check_kflag_member = btf_generic_check_kflag_member,
3256 .log_details = btf_struct_log,
3257 .show = btf_struct_show,
3260 static int btf_enum_check_member(struct btf_verifier_env *env,
3261 const struct btf_type *struct_type,
3262 const struct btf_member *member,
3263 const struct btf_type *member_type)
3265 u32 struct_bits_off = member->offset;
3266 u32 struct_size, bytes_offset;
3268 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3269 btf_verifier_log_member(env, struct_type, member,
3270 "Member is not byte aligned");
3274 struct_size = struct_type->size;
3275 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3276 if (struct_size - bytes_offset < member_type->size) {
3277 btf_verifier_log_member(env, struct_type, member,
3278 "Member exceeds struct_size");
3285 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3286 const struct btf_type *struct_type,
3287 const struct btf_member *member,
3288 const struct btf_type *member_type)
3290 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3291 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3293 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3294 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3296 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3297 btf_verifier_log_member(env, struct_type, member,
3298 "Member is not byte aligned");
3302 nr_bits = int_bitsize;
3303 } else if (nr_bits > int_bitsize) {
3304 btf_verifier_log_member(env, struct_type, member,
3305 "Invalid member bitfield_size");
3309 struct_size = struct_type->size;
3310 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3311 if (struct_size < bytes_end) {
3312 btf_verifier_log_member(env, struct_type, member,
3313 "Member exceeds struct_size");
3320 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3321 const struct btf_type *t,
3324 const struct btf_enum *enums = btf_type_enum(t);
3325 struct btf *btf = env->btf;
3329 nr_enums = btf_type_vlen(t);
3330 meta_needed = nr_enums * sizeof(*enums);
3332 if (meta_left < meta_needed) {
3333 btf_verifier_log_basic(env, t,
3334 "meta_left:%u meta_needed:%u",
3335 meta_left, meta_needed);
3339 if (btf_type_kflag(t)) {
3340 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3344 if (t->size > 8 || !is_power_of_2(t->size)) {
3345 btf_verifier_log_type(env, t, "Unexpected size");
3349 /* enum type either no name or a valid one */
3351 !btf_name_valid_identifier(env->btf, t->name_off)) {
3352 btf_verifier_log_type(env, t, "Invalid name");
3356 btf_verifier_log_type(env, t, NULL);
3358 for (i = 0; i < nr_enums; i++) {
3359 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3360 btf_verifier_log(env, "\tInvalid name_offset:%u",
3365 /* enum member must have a valid name */
3366 if (!enums[i].name_off ||
3367 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3368 btf_verifier_log_type(env, t, "Invalid name");
3372 if (env->log.level == BPF_LOG_KERNEL)
3374 btf_verifier_log(env, "\t%s val=%d\n",
3375 __btf_name_by_offset(btf, enums[i].name_off),
3382 static void btf_enum_log(struct btf_verifier_env *env,
3383 const struct btf_type *t)
3385 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3388 static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
3389 u32 type_id, void *data, u8 bits_offset,
3390 struct btf_show *show)
3392 const struct btf_enum *enums = btf_type_enum(t);
3393 u32 i, nr_enums = btf_type_vlen(t);
3397 safe_data = btf_show_start_type(show, t, type_id, data);
3401 v = *(int *)safe_data;
3403 for (i = 0; i < nr_enums; i++) {
3404 if (v != enums[i].val)
3407 btf_show_type_value(show, "%s",
3408 __btf_name_by_offset(btf,
3409 enums[i].name_off));
3411 btf_show_end_type(show);
3415 btf_show_type_value(show, "%d", v);
3416 btf_show_end_type(show);
3419 static struct btf_kind_operations enum_ops = {
3420 .check_meta = btf_enum_check_meta,
3421 .resolve = btf_df_resolve,
3422 .check_member = btf_enum_check_member,
3423 .check_kflag_member = btf_enum_check_kflag_member,
3424 .log_details = btf_enum_log,
3425 .show = btf_enum_show,
3428 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
3429 const struct btf_type *t,
3432 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
3434 if (meta_left < meta_needed) {
3435 btf_verifier_log_basic(env, t,
3436 "meta_left:%u meta_needed:%u",
3437 meta_left, meta_needed);
3442 btf_verifier_log_type(env, t, "Invalid name");
3446 if (btf_type_kflag(t)) {
3447 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3451 btf_verifier_log_type(env, t, NULL);
3456 static void btf_func_proto_log(struct btf_verifier_env *env,
3457 const struct btf_type *t)
3459 const struct btf_param *args = (const struct btf_param *)(t + 1);
3460 u16 nr_args = btf_type_vlen(t), i;
3462 btf_verifier_log(env, "return=%u args=(", t->type);
3464 btf_verifier_log(env, "void");
3468 if (nr_args == 1 && !args[0].type) {
3469 /* Only one vararg */
3470 btf_verifier_log(env, "vararg");
3474 btf_verifier_log(env, "%u %s", args[0].type,
3475 __btf_name_by_offset(env->btf,
3477 for (i = 1; i < nr_args - 1; i++)
3478 btf_verifier_log(env, ", %u %s", args[i].type,
3479 __btf_name_by_offset(env->btf,
3483 const struct btf_param *last_arg = &args[nr_args - 1];
3486 btf_verifier_log(env, ", %u %s", last_arg->type,
3487 __btf_name_by_offset(env->btf,
3488 last_arg->name_off));
3490 btf_verifier_log(env, ", vararg");
3494 btf_verifier_log(env, ")");
3497 static struct btf_kind_operations func_proto_ops = {
3498 .check_meta = btf_func_proto_check_meta,
3499 .resolve = btf_df_resolve,
3501 * BTF_KIND_FUNC_PROTO cannot be directly referred by
3502 * a struct's member.
3504 * It should be a function pointer instead.
3505 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
3507 * Hence, there is no btf_func_check_member().
3509 .check_member = btf_df_check_member,
3510 .check_kflag_member = btf_df_check_kflag_member,
3511 .log_details = btf_func_proto_log,
3512 .show = btf_df_show,
3515 static s32 btf_func_check_meta(struct btf_verifier_env *env,
3516 const struct btf_type *t,
3520 !btf_name_valid_identifier(env->btf, t->name_off)) {
3521 btf_verifier_log_type(env, t, "Invalid name");
3525 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
3526 btf_verifier_log_type(env, t, "Invalid func linkage");
3530 if (btf_type_kflag(t)) {
3531 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3535 btf_verifier_log_type(env, t, NULL);
3540 static int btf_func_resolve(struct btf_verifier_env *env,
3541 const struct resolve_vertex *v)
3543 const struct btf_type *t = v->t;
3544 u32 next_type_id = t->type;
3547 err = btf_func_check(env, t);
3551 env_stack_pop_resolved(env, next_type_id, 0);
3555 static struct btf_kind_operations func_ops = {
3556 .check_meta = btf_func_check_meta,
3557 .resolve = btf_func_resolve,
3558 .check_member = btf_df_check_member,
3559 .check_kflag_member = btf_df_check_kflag_member,
3560 .log_details = btf_ref_type_log,
3561 .show = btf_df_show,
3564 static s32 btf_var_check_meta(struct btf_verifier_env *env,
3565 const struct btf_type *t,
3568 const struct btf_var *var;
3569 u32 meta_needed = sizeof(*var);
3571 if (meta_left < meta_needed) {
3572 btf_verifier_log_basic(env, t,
3573 "meta_left:%u meta_needed:%u",
3574 meta_left, meta_needed);
3578 if (btf_type_vlen(t)) {
3579 btf_verifier_log_type(env, t, "vlen != 0");
3583 if (btf_type_kflag(t)) {
3584 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3589 !__btf_name_valid(env->btf, t->name_off, true)) {
3590 btf_verifier_log_type(env, t, "Invalid name");
3594 /* A var cannot be in type void */
3595 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
3596 btf_verifier_log_type(env, t, "Invalid type_id");
3600 var = btf_type_var(t);
3601 if (var->linkage != BTF_VAR_STATIC &&
3602 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
3603 btf_verifier_log_type(env, t, "Linkage not supported");
3607 btf_verifier_log_type(env, t, NULL);
3612 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
3614 const struct btf_var *var = btf_type_var(t);
3616 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
3619 static const struct btf_kind_operations var_ops = {
3620 .check_meta = btf_var_check_meta,
3621 .resolve = btf_var_resolve,
3622 .check_member = btf_df_check_member,
3623 .check_kflag_member = btf_df_check_kflag_member,
3624 .log_details = btf_var_log,
3625 .show = btf_var_show,
3628 static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
3629 const struct btf_type *t,
3632 const struct btf_var_secinfo *vsi;
3633 u64 last_vsi_end_off = 0, sum = 0;
3636 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
3637 if (meta_left < meta_needed) {
3638 btf_verifier_log_basic(env, t,
3639 "meta_left:%u meta_needed:%u",
3640 meta_left, meta_needed);
3645 btf_verifier_log_type(env, t, "size == 0");
3649 if (btf_type_kflag(t)) {
3650 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3655 !btf_name_valid_section(env->btf, t->name_off)) {
3656 btf_verifier_log_type(env, t, "Invalid name");
3660 btf_verifier_log_type(env, t, NULL);
3662 for_each_vsi(i, t, vsi) {
3663 /* A var cannot be in type void */
3664 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
3665 btf_verifier_log_vsi(env, t, vsi,
3670 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
3671 btf_verifier_log_vsi(env, t, vsi,
3676 if (!vsi->size || vsi->size > t->size) {
3677 btf_verifier_log_vsi(env, t, vsi,
3682 last_vsi_end_off = vsi->offset + vsi->size;
3683 if (last_vsi_end_off > t->size) {
3684 btf_verifier_log_vsi(env, t, vsi,
3685 "Invalid offset+size");
3689 btf_verifier_log_vsi(env, t, vsi, NULL);
3693 if (t->size < sum) {
3694 btf_verifier_log_type(env, t, "Invalid btf_info size");
3701 static int btf_datasec_resolve(struct btf_verifier_env *env,
3702 const struct resolve_vertex *v)
3704 const struct btf_var_secinfo *vsi;
3705 struct btf *btf = env->btf;
3708 for_each_vsi_from(i, v->next_member, v->t, vsi) {
3709 u32 var_type_id = vsi->type, type_id, type_size = 0;
3710 const struct btf_type *var_type = btf_type_by_id(env->btf,
3712 if (!var_type || !btf_type_is_var(var_type)) {
3713 btf_verifier_log_vsi(env, v->t, vsi,
3714 "Not a VAR kind member");
3718 if (!env_type_is_resolve_sink(env, var_type) &&
3719 !env_type_is_resolved(env, var_type_id)) {
3720 env_stack_set_next_member(env, i + 1);
3721 return env_stack_push(env, var_type, var_type_id);
3724 type_id = var_type->type;
3725 if (!btf_type_id_size(btf, &type_id, &type_size)) {
3726 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
3730 if (vsi->size < type_size) {
3731 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
3736 env_stack_pop_resolved(env, 0, 0);
3740 static void btf_datasec_log(struct btf_verifier_env *env,
3741 const struct btf_type *t)
3743 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3746 static void btf_datasec_show(const struct btf *btf,
3747 const struct btf_type *t, u32 type_id,
3748 void *data, u8 bits_offset,
3749 struct btf_show *show)
3751 const struct btf_var_secinfo *vsi;
3752 const struct btf_type *var;
3755 if (!btf_show_start_type(show, t, type_id, data))
3758 btf_show_type_value(show, "section (\"%s\") = {",
3759 __btf_name_by_offset(btf, t->name_off));
3760 for_each_vsi(i, t, vsi) {
3761 var = btf_type_by_id(btf, vsi->type);
3763 btf_show(show, ",");
3764 btf_type_ops(var)->show(btf, var, vsi->type,
3765 data + vsi->offset, bits_offset, show);
3767 btf_show_end_type(show);
3770 static const struct btf_kind_operations datasec_ops = {
3771 .check_meta = btf_datasec_check_meta,
3772 .resolve = btf_datasec_resolve,
3773 .check_member = btf_df_check_member,
3774 .check_kflag_member = btf_df_check_kflag_member,
3775 .log_details = btf_datasec_log,
3776 .show = btf_datasec_show,
3779 static s32 btf_float_check_meta(struct btf_verifier_env *env,
3780 const struct btf_type *t,
3783 if (btf_type_vlen(t)) {
3784 btf_verifier_log_type(env, t, "vlen != 0");
3788 if (btf_type_kflag(t)) {
3789 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3793 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
3795 btf_verifier_log_type(env, t, "Invalid type_size");
3799 btf_verifier_log_type(env, t, NULL);
3804 static int btf_float_check_member(struct btf_verifier_env *env,
3805 const struct btf_type *struct_type,
3806 const struct btf_member *member,
3807 const struct btf_type *member_type)
3809 u64 start_offset_bytes;
3810 u64 end_offset_bytes;
3815 /* Different architectures have different alignment requirements, so
3816 * here we check only for the reasonable minimum. This way we ensure
3817 * that types after CO-RE can pass the kernel BTF verifier.
3819 align_bytes = min_t(u64, sizeof(void *), member_type->size);
3820 align_bits = align_bytes * BITS_PER_BYTE;
3821 div64_u64_rem(member->offset, align_bits, &misalign_bits);
3822 if (misalign_bits) {
3823 btf_verifier_log_member(env, struct_type, member,
3824 "Member is not properly aligned");
3828 start_offset_bytes = member->offset / BITS_PER_BYTE;
3829 end_offset_bytes = start_offset_bytes + member_type->size;
3830 if (end_offset_bytes > struct_type->size) {
3831 btf_verifier_log_member(env, struct_type, member,
3832 "Member exceeds struct_size");
3839 static void btf_float_log(struct btf_verifier_env *env,
3840 const struct btf_type *t)
3842 btf_verifier_log(env, "size=%u", t->size);
3845 static const struct btf_kind_operations float_ops = {
3846 .check_meta = btf_float_check_meta,
3847 .resolve = btf_df_resolve,
3848 .check_member = btf_float_check_member,
3849 .check_kflag_member = btf_generic_check_kflag_member,
3850 .log_details = btf_float_log,
3851 .show = btf_df_show,
3854 static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
3855 const struct btf_type *t,
3858 const struct btf_decl_tag *tag;
3859 u32 meta_needed = sizeof(*tag);
3863 if (meta_left < meta_needed) {
3864 btf_verifier_log_basic(env, t,
3865 "meta_left:%u meta_needed:%u",
3866 meta_left, meta_needed);
3870 value = btf_name_by_offset(env->btf, t->name_off);
3871 if (!value || !value[0]) {
3872 btf_verifier_log_type(env, t, "Invalid value");
3876 if (btf_type_vlen(t)) {
3877 btf_verifier_log_type(env, t, "vlen != 0");
3881 if (btf_type_kflag(t)) {
3882 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3886 component_idx = btf_type_decl_tag(t)->component_idx;
3887 if (component_idx < -1) {
3888 btf_verifier_log_type(env, t, "Invalid component_idx");
3892 btf_verifier_log_type(env, t, NULL);
3897 static int btf_decl_tag_resolve(struct btf_verifier_env *env,
3898 const struct resolve_vertex *v)
3900 const struct btf_type *next_type;
3901 const struct btf_type *t = v->t;
3902 u32 next_type_id = t->type;
3903 struct btf *btf = env->btf;
3907 next_type = btf_type_by_id(btf, next_type_id);
3908 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
3909 btf_verifier_log_type(env, v->t, "Invalid type_id");
3913 if (!env_type_is_resolve_sink(env, next_type) &&
3914 !env_type_is_resolved(env, next_type_id))
3915 return env_stack_push(env, next_type, next_type_id);
3917 component_idx = btf_type_decl_tag(t)->component_idx;
3918 if (component_idx != -1) {
3919 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
3920 btf_verifier_log_type(env, v->t, "Invalid component_idx");
3924 if (btf_type_is_struct(next_type)) {
3925 vlen = btf_type_vlen(next_type);
3927 /* next_type should be a function */
3928 next_type = btf_type_by_id(btf, next_type->type);
3929 vlen = btf_type_vlen(next_type);
3932 if ((u32)component_idx >= vlen) {
3933 btf_verifier_log_type(env, v->t, "Invalid component_idx");
3938 env_stack_pop_resolved(env, next_type_id, 0);
3943 static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
3945 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
3946 btf_type_decl_tag(t)->component_idx);
3949 static const struct btf_kind_operations decl_tag_ops = {
3950 .check_meta = btf_decl_tag_check_meta,
3951 .resolve = btf_decl_tag_resolve,
3952 .check_member = btf_df_check_member,
3953 .check_kflag_member = btf_df_check_kflag_member,
3954 .log_details = btf_decl_tag_log,
3955 .show = btf_df_show,
3958 static int btf_func_proto_check(struct btf_verifier_env *env,
3959 const struct btf_type *t)
3961 const struct btf_type *ret_type;
3962 const struct btf_param *args;
3963 const struct btf *btf;
3968 args = (const struct btf_param *)(t + 1);
3969 nr_args = btf_type_vlen(t);
3971 /* Check func return type which could be "void" (t->type == 0) */
3973 u32 ret_type_id = t->type;
3975 ret_type = btf_type_by_id(btf, ret_type_id);
3977 btf_verifier_log_type(env, t, "Invalid return type");
3981 if (btf_type_needs_resolve(ret_type) &&
3982 !env_type_is_resolved(env, ret_type_id)) {
3983 err = btf_resolve(env, ret_type, ret_type_id);
3988 /* Ensure the return type is a type that has a size */
3989 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
3990 btf_verifier_log_type(env, t, "Invalid return type");
3998 /* Last func arg type_id could be 0 if it is a vararg */
3999 if (!args[nr_args - 1].type) {
4000 if (args[nr_args - 1].name_off) {
4001 btf_verifier_log_type(env, t, "Invalid arg#%u",
4009 for (i = 0; i < nr_args; i++) {
4010 const struct btf_type *arg_type;
4013 arg_type_id = args[i].type;
4014 arg_type = btf_type_by_id(btf, arg_type_id);
4016 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4021 if (args[i].name_off &&
4022 (!btf_name_offset_valid(btf, args[i].name_off) ||
4023 !btf_name_valid_identifier(btf, args[i].name_off))) {
4024 btf_verifier_log_type(env, t,
4025 "Invalid arg#%u", i + 1);
4030 if (btf_type_needs_resolve(arg_type) &&
4031 !env_type_is_resolved(env, arg_type_id)) {
4032 err = btf_resolve(env, arg_type, arg_type_id);
4037 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4038 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4047 static int btf_func_check(struct btf_verifier_env *env,
4048 const struct btf_type *t)
4050 const struct btf_type *proto_type;
4051 const struct btf_param *args;
4052 const struct btf *btf;
4056 proto_type = btf_type_by_id(btf, t->type);
4058 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4059 btf_verifier_log_type(env, t, "Invalid type_id");
4063 args = (const struct btf_param *)(proto_type + 1);
4064 nr_args = btf_type_vlen(proto_type);
4065 for (i = 0; i < nr_args; i++) {
4066 if (!args[i].name_off && args[i].type) {
4067 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4075 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4076 [BTF_KIND_INT] = &int_ops,
4077 [BTF_KIND_PTR] = &ptr_ops,
4078 [BTF_KIND_ARRAY] = &array_ops,
4079 [BTF_KIND_STRUCT] = &struct_ops,
4080 [BTF_KIND_UNION] = &struct_ops,
4081 [BTF_KIND_ENUM] = &enum_ops,
4082 [BTF_KIND_FWD] = &fwd_ops,
4083 [BTF_KIND_TYPEDEF] = &modifier_ops,
4084 [BTF_KIND_VOLATILE] = &modifier_ops,
4085 [BTF_KIND_CONST] = &modifier_ops,
4086 [BTF_KIND_RESTRICT] = &modifier_ops,
4087 [BTF_KIND_FUNC] = &func_ops,
4088 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4089 [BTF_KIND_VAR] = &var_ops,
4090 [BTF_KIND_DATASEC] = &datasec_ops,
4091 [BTF_KIND_FLOAT] = &float_ops,
4092 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4093 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4096 static s32 btf_check_meta(struct btf_verifier_env *env,
4097 const struct btf_type *t,
4100 u32 saved_meta_left = meta_left;
4103 if (meta_left < sizeof(*t)) {
4104 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4105 env->log_type_id, meta_left, sizeof(*t));
4108 meta_left -= sizeof(*t);
4110 if (t->info & ~BTF_INFO_MASK) {
4111 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4112 env->log_type_id, t->info);
4116 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4117 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4118 btf_verifier_log(env, "[%u] Invalid kind:%u",
4119 env->log_type_id, BTF_INFO_KIND(t->info));
4123 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4124 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4125 env->log_type_id, t->name_off);
4129 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4130 if (var_meta_size < 0)
4131 return var_meta_size;
4133 meta_left -= var_meta_size;
4135 return saved_meta_left - meta_left;
4138 static int btf_check_all_metas(struct btf_verifier_env *env)
4140 struct btf *btf = env->btf;
4141 struct btf_header *hdr;
4145 cur = btf->nohdr_data + hdr->type_off;
4146 end = cur + hdr->type_len;
4148 env->log_type_id = btf->base_btf ? btf->start_id : 1;
4150 struct btf_type *t = cur;
4153 meta_size = btf_check_meta(env, t, end - cur);
4157 btf_add_type(env, t);
4165 static bool btf_resolve_valid(struct btf_verifier_env *env,
4166 const struct btf_type *t,
4169 struct btf *btf = env->btf;
4171 if (!env_type_is_resolved(env, type_id))
4174 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
4175 return !btf_resolved_type_id(btf, type_id) &&
4176 !btf_resolved_type_size(btf, type_id);
4178 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
4179 return btf_resolved_type_id(btf, type_id) &&
4180 !btf_resolved_type_size(btf, type_id);
4182 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
4183 btf_type_is_var(t)) {
4184 t = btf_type_id_resolve(btf, &type_id);
4186 !btf_type_is_modifier(t) &&
4187 !btf_type_is_var(t) &&
4188 !btf_type_is_datasec(t);
4191 if (btf_type_is_array(t)) {
4192 const struct btf_array *array = btf_type_array(t);
4193 const struct btf_type *elem_type;
4194 u32 elem_type_id = array->type;
4197 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
4198 return elem_type && !btf_type_is_modifier(elem_type) &&
4199 (array->nelems * elem_size ==
4200 btf_resolved_type_size(btf, type_id));
4206 static int btf_resolve(struct btf_verifier_env *env,
4207 const struct btf_type *t, u32 type_id)
4209 u32 save_log_type_id = env->log_type_id;
4210 const struct resolve_vertex *v;
4213 env->resolve_mode = RESOLVE_TBD;
4214 env_stack_push(env, t, type_id);
4215 while (!err && (v = env_stack_peak(env))) {
4216 env->log_type_id = v->type_id;
4217 err = btf_type_ops(v->t)->resolve(env, v);
4220 env->log_type_id = type_id;
4221 if (err == -E2BIG) {
4222 btf_verifier_log_type(env, t,
4223 "Exceeded max resolving depth:%u",
4225 } else if (err == -EEXIST) {
4226 btf_verifier_log_type(env, t, "Loop detected");
4229 /* Final sanity check */
4230 if (!err && !btf_resolve_valid(env, t, type_id)) {
4231 btf_verifier_log_type(env, t, "Invalid resolve state");
4235 env->log_type_id = save_log_type_id;
4239 static int btf_check_all_types(struct btf_verifier_env *env)
4241 struct btf *btf = env->btf;
4242 const struct btf_type *t;
4246 err = env_resolve_init(env);
4251 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
4252 type_id = btf->start_id + i;
4253 t = btf_type_by_id(btf, type_id);
4255 env->log_type_id = type_id;
4256 if (btf_type_needs_resolve(t) &&
4257 !env_type_is_resolved(env, type_id)) {
4258 err = btf_resolve(env, t, type_id);
4263 if (btf_type_is_func_proto(t)) {
4264 err = btf_func_proto_check(env, t);
4273 static int btf_parse_type_sec(struct btf_verifier_env *env)
4275 const struct btf_header *hdr = &env->btf->hdr;
4278 /* Type section must align to 4 bytes */
4279 if (hdr->type_off & (sizeof(u32) - 1)) {
4280 btf_verifier_log(env, "Unaligned type_off");
4284 if (!env->btf->base_btf && !hdr->type_len) {
4285 btf_verifier_log(env, "No type found");
4289 err = btf_check_all_metas(env);
4293 return btf_check_all_types(env);
4296 static int btf_parse_str_sec(struct btf_verifier_env *env)
4298 const struct btf_header *hdr;
4299 struct btf *btf = env->btf;
4300 const char *start, *end;
4303 start = btf->nohdr_data + hdr->str_off;
4304 end = start + hdr->str_len;
4306 if (end != btf->data + btf->data_size) {
4307 btf_verifier_log(env, "String section is not at the end");
4311 btf->strings = start;
4313 if (btf->base_btf && !hdr->str_len)
4315 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
4316 btf_verifier_log(env, "Invalid string section");
4319 if (!btf->base_btf && start[0]) {
4320 btf_verifier_log(env, "Invalid string section");
4327 static const size_t btf_sec_info_offset[] = {
4328 offsetof(struct btf_header, type_off),
4329 offsetof(struct btf_header, str_off),
4332 static int btf_sec_info_cmp(const void *a, const void *b)
4334 const struct btf_sec_info *x = a;
4335 const struct btf_sec_info *y = b;
4337 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
4340 static int btf_check_sec_info(struct btf_verifier_env *env,
4343 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
4344 u32 total, expected_total, i;
4345 const struct btf_header *hdr;
4346 const struct btf *btf;
4351 /* Populate the secs from hdr */
4352 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
4353 secs[i] = *(struct btf_sec_info *)((void *)hdr +
4354 btf_sec_info_offset[i]);
4356 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
4357 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
4359 /* Check for gaps and overlap among sections */
4361 expected_total = btf_data_size - hdr->hdr_len;
4362 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
4363 if (expected_total < secs[i].off) {
4364 btf_verifier_log(env, "Invalid section offset");
4367 if (total < secs[i].off) {
4369 btf_verifier_log(env, "Unsupported section found");
4372 if (total > secs[i].off) {
4373 btf_verifier_log(env, "Section overlap found");
4376 if (expected_total - total < secs[i].len) {
4377 btf_verifier_log(env,
4378 "Total section length too long");
4381 total += secs[i].len;
4384 /* There is data other than hdr and known sections */
4385 if (expected_total != total) {
4386 btf_verifier_log(env, "Unsupported section found");
4393 static int btf_parse_hdr(struct btf_verifier_env *env)
4395 u32 hdr_len, hdr_copy, btf_data_size;
4396 const struct btf_header *hdr;
4401 btf_data_size = btf->data_size;
4404 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
4405 btf_verifier_log(env, "hdr_len not found");
4410 hdr_len = hdr->hdr_len;
4411 if (btf_data_size < hdr_len) {
4412 btf_verifier_log(env, "btf_header not found");
4416 /* Ensure the unsupported header fields are zero */
4417 if (hdr_len > sizeof(btf->hdr)) {
4418 u8 *expected_zero = btf->data + sizeof(btf->hdr);
4419 u8 *end = btf->data + hdr_len;
4421 for (; expected_zero < end; expected_zero++) {
4422 if (*expected_zero) {
4423 btf_verifier_log(env, "Unsupported btf_header");
4429 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
4430 memcpy(&btf->hdr, btf->data, hdr_copy);
4434 btf_verifier_log_hdr(env, btf_data_size);
4436 if (hdr->magic != BTF_MAGIC) {
4437 btf_verifier_log(env, "Invalid magic");
4441 if (hdr->version != BTF_VERSION) {
4442 btf_verifier_log(env, "Unsupported version");
4447 btf_verifier_log(env, "Unsupported flags");
4451 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
4452 btf_verifier_log(env, "No data");
4456 err = btf_check_sec_info(env, btf_data_size);
4463 static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
4464 u32 log_level, char __user *log_ubuf, u32 log_size)
4466 struct btf_verifier_env *env = NULL;
4467 struct bpf_verifier_log *log;
4468 struct btf *btf = NULL;
4472 if (btf_data_size > BTF_MAX_SIZE)
4473 return ERR_PTR(-E2BIG);
4475 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4477 return ERR_PTR(-ENOMEM);
4480 if (log_level || log_ubuf || log_size) {
4481 /* user requested verbose verifier output
4482 * and supplied buffer to store the verification trace
4484 log->level = log_level;
4485 log->ubuf = log_ubuf;
4486 log->len_total = log_size;
4488 /* log attributes have to be sane */
4489 if (!bpf_verifier_log_attr_valid(log)) {
4495 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4502 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
4509 btf->data_size = btf_data_size;
4511 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
4516 err = btf_parse_hdr(env);
4520 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4522 err = btf_parse_str_sec(env);
4526 err = btf_parse_type_sec(env);
4530 if (log->level && bpf_verifier_log_full(log)) {
4535 btf_verifier_env_free(env);
4536 refcount_set(&btf->refcnt, 1);
4540 btf_verifier_env_free(env);
4543 return ERR_PTR(err);
4546 extern char __weak __start_BTF[];
4547 extern char __weak __stop_BTF[];
4548 extern struct btf *btf_vmlinux;
4550 #define BPF_MAP_TYPE(_id, _ops)
4551 #define BPF_LINK_TYPE(_id, _name)
4553 struct bpf_ctx_convert {
4554 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4555 prog_ctx_type _id##_prog; \
4556 kern_ctx_type _id##_kern;
4557 #include <linux/bpf_types.h>
4558 #undef BPF_PROG_TYPE
4560 /* 't' is written once under lock. Read many times. */
4561 const struct btf_type *t;
4564 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4566 #include <linux/bpf_types.h>
4567 #undef BPF_PROG_TYPE
4568 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
4570 static u8 bpf_ctx_convert_map[] = {
4571 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4572 [_id] = __ctx_convert##_id,
4573 #include <linux/bpf_types.h>
4574 #undef BPF_PROG_TYPE
4575 0, /* avoid empty array */
4578 #undef BPF_LINK_TYPE
4580 static const struct btf_member *
4581 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
4582 const struct btf_type *t, enum bpf_prog_type prog_type,
4585 const struct btf_type *conv_struct;
4586 const struct btf_type *ctx_struct;
4587 const struct btf_member *ctx_type;
4588 const char *tname, *ctx_tname;
4590 conv_struct = bpf_ctx_convert.t;
4592 bpf_log(log, "btf_vmlinux is malformed\n");
4595 t = btf_type_by_id(btf, t->type);
4596 while (btf_type_is_modifier(t))
4597 t = btf_type_by_id(btf, t->type);
4598 if (!btf_type_is_struct(t)) {
4599 /* Only pointer to struct is supported for now.
4600 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
4601 * is not supported yet.
4602 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
4606 tname = btf_name_by_offset(btf, t->name_off);
4608 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
4611 /* prog_type is valid bpf program type. No need for bounds check. */
4612 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
4613 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
4614 * Like 'struct __sk_buff'
4616 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
4618 /* should not happen */
4620 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
4622 /* should not happen */
4623 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
4626 /* only compare that prog's ctx type name is the same as
4627 * kernel expects. No need to compare field by field.
4628 * It's ok for bpf prog to do:
4629 * struct __sk_buff {};
4630 * int socket_filter_bpf_prog(struct __sk_buff *skb)
4631 * { // no fields of skb are ever used }
4633 if (strcmp(ctx_tname, tname))
4638 static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = {
4639 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
4640 #define BPF_LINK_TYPE(_id, _name)
4641 #define BPF_MAP_TYPE(_id, _ops) \
4643 #include <linux/bpf_types.h>
4644 #undef BPF_PROG_TYPE
4645 #undef BPF_LINK_TYPE
4649 static int btf_vmlinux_map_ids_init(const struct btf *btf,
4650 struct bpf_verifier_log *log)
4652 const struct bpf_map_ops *ops;
4655 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) {
4656 ops = btf_vmlinux_map_ops[i];
4657 if (!ops || (!ops->map_btf_name && !ops->map_btf_id))
4659 if (!ops->map_btf_name || !ops->map_btf_id) {
4660 bpf_log(log, "map type %d is misconfigured\n", i);
4663 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name,
4667 *ops->map_btf_id = btf_id;
4673 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
4675 const struct btf_type *t,
4676 enum bpf_prog_type prog_type,
4679 const struct btf_member *prog_ctx_type, *kern_ctx_type;
4681 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
4684 kern_ctx_type = prog_ctx_type + 1;
4685 return kern_ctx_type->type;
4688 BTF_ID_LIST(bpf_ctx_convert_btf_id)
4689 BTF_ID(struct, bpf_ctx_convert)
4691 struct btf *btf_parse_vmlinux(void)
4693 struct btf_verifier_env *env = NULL;
4694 struct bpf_verifier_log *log;
4695 struct btf *btf = NULL;
4698 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4700 return ERR_PTR(-ENOMEM);
4703 log->level = BPF_LOG_KERNEL;
4705 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4712 btf->data = __start_BTF;
4713 btf->data_size = __stop_BTF - __start_BTF;
4714 btf->kernel_btf = true;
4715 snprintf(btf->name, sizeof(btf->name), "vmlinux");
4717 err = btf_parse_hdr(env);
4721 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4723 err = btf_parse_str_sec(env);
4727 err = btf_check_all_metas(env);
4731 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
4732 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
4734 /* find bpf map structs for map_ptr access checking */
4735 err = btf_vmlinux_map_ids_init(btf, log);
4739 bpf_struct_ops_init(btf, log);
4741 refcount_set(&btf->refcnt, 1);
4743 err = btf_alloc_id(btf);
4747 btf_verifier_env_free(env);
4751 btf_verifier_env_free(env);
4756 return ERR_PTR(err);
4759 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
4761 static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
4763 struct btf_verifier_env *env = NULL;
4764 struct bpf_verifier_log *log;
4765 struct btf *btf = NULL, *base_btf;
4768 base_btf = bpf_get_btf_vmlinux();
4769 if (IS_ERR(base_btf))
4772 return ERR_PTR(-EINVAL);
4774 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4776 return ERR_PTR(-ENOMEM);
4779 log->level = BPF_LOG_KERNEL;
4781 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4788 btf->base_btf = base_btf;
4789 btf->start_id = base_btf->nr_types;
4790 btf->start_str_off = base_btf->hdr.str_len;
4791 btf->kernel_btf = true;
4792 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
4794 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
4799 memcpy(btf->data, data, data_size);
4800 btf->data_size = data_size;
4802 err = btf_parse_hdr(env);
4806 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4808 err = btf_parse_str_sec(env);
4812 err = btf_check_all_metas(env);
4816 btf_verifier_env_free(env);
4817 refcount_set(&btf->refcnt, 1);
4821 btf_verifier_env_free(env);
4827 return ERR_PTR(err);
4830 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
4832 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
4834 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4837 return tgt_prog->aux->btf;
4839 return prog->aux->attach_btf;
4842 static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
4844 /* t comes in already as a pointer */
4845 t = btf_type_by_id(btf, t->type);
4848 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
4849 t = btf_type_by_id(btf, t->type);
4851 return btf_type_is_int(t);
4854 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
4855 const struct bpf_prog *prog,
4856 struct bpf_insn_access_aux *info)
4858 const struct btf_type *t = prog->aux->attach_func_proto;
4859 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4860 struct btf *btf = bpf_prog_get_target_btf(prog);
4861 const char *tname = prog->aux->attach_func_name;
4862 struct bpf_verifier_log *log = info->log;
4863 const struct btf_param *args;
4868 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
4873 args = (const struct btf_param *)(t + 1);
4874 /* if (t == NULL) Fall back to default BPF prog with
4875 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
4877 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
4878 if (prog->aux->attach_btf_trace) {
4879 /* skip first 'void *__data' argument in btf_trace_##name typedef */
4884 if (arg > nr_args) {
4885 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4890 if (arg == nr_args) {
4891 switch (prog->expected_attach_type) {
4893 case BPF_TRACE_FEXIT:
4894 /* When LSM programs are attached to void LSM hooks
4895 * they use FEXIT trampolines and when attached to
4896 * int LSM hooks, they use MODIFY_RETURN trampolines.
4898 * While the LSM programs are BPF_MODIFY_RETURN-like
4901 * if (ret_type != 'int')
4904 * is _not_ done here. This is still safe as LSM hooks
4905 * have only void and int return types.
4909 t = btf_type_by_id(btf, t->type);
4911 case BPF_MODIFY_RETURN:
4912 /* For now the BPF_MODIFY_RETURN can only be attached to
4913 * functions that return an int.
4918 t = btf_type_skip_modifiers(btf, t->type, NULL);
4919 if (!btf_type_is_small_int(t)) {
4921 "ret type %s not allowed for fmod_ret\n",
4922 btf_kind_str[BTF_INFO_KIND(t->info)]);
4927 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4933 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
4935 t = btf_type_by_id(btf, args[arg].type);
4938 /* skip modifiers */
4939 while (btf_type_is_modifier(t))
4940 t = btf_type_by_id(btf, t->type);
4941 if (btf_type_is_small_int(t) || btf_type_is_enum(t))
4942 /* accessing a scalar */
4944 if (!btf_type_is_ptr(t)) {
4946 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
4948 __btf_name_by_offset(btf, t->name_off),
4949 btf_kind_str[BTF_INFO_KIND(t->info)]);
4953 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
4954 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4955 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4958 type = base_type(ctx_arg_info->reg_type);
4959 flag = type_flag(ctx_arg_info->reg_type);
4960 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
4961 (flag & PTR_MAYBE_NULL)) {
4962 info->reg_type = ctx_arg_info->reg_type;
4968 /* This is a pointer to void.
4969 * It is the same as scalar from the verifier safety pov.
4970 * No further pointer walking is allowed.
4974 if (is_int_ptr(btf, t))
4977 /* this is a pointer to another type */
4978 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4979 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4981 if (ctx_arg_info->offset == off) {
4982 if (!ctx_arg_info->btf_id) {
4983 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
4987 info->reg_type = ctx_arg_info->reg_type;
4988 info->btf = btf_vmlinux;
4989 info->btf_id = ctx_arg_info->btf_id;
4994 info->reg_type = PTR_TO_BTF_ID;
4996 enum bpf_prog_type tgt_type;
4998 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
4999 tgt_type = tgt_prog->aux->saved_dst_prog_type;
5001 tgt_type = tgt_prog->type;
5003 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
5005 info->btf = btf_vmlinux;
5014 info->btf_id = t->type;
5015 t = btf_type_by_id(btf, t->type);
5016 /* skip modifiers */
5017 while (btf_type_is_modifier(t)) {
5018 info->btf_id = t->type;
5019 t = btf_type_by_id(btf, t->type);
5021 if (!btf_type_is_struct(t)) {
5023 "func '%s' arg%d type %s is not a struct\n",
5024 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]);
5027 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
5028 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)],
5029 __btf_name_by_offset(btf, t->name_off));
5033 enum bpf_struct_walk_result {
5040 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
5041 const struct btf_type *t, int off, int size,
5044 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
5045 const struct btf_type *mtype, *elem_type = NULL;
5046 const struct btf_member *member;
5047 const char *tname, *mname;
5048 u32 vlen, elem_id, mid;
5051 tname = __btf_name_by_offset(btf, t->name_off);
5052 if (!btf_type_is_struct(t)) {
5053 bpf_log(log, "Type '%s' is not a struct\n", tname);
5057 vlen = btf_type_vlen(t);
5058 if (off + size > t->size) {
5059 /* If the last element is a variable size array, we may
5060 * need to relax the rule.
5062 struct btf_array *array_elem;
5067 member = btf_type_member(t) + vlen - 1;
5068 mtype = btf_type_skip_modifiers(btf, member->type,
5070 if (!btf_type_is_array(mtype))
5073 array_elem = (struct btf_array *)(mtype + 1);
5074 if (array_elem->nelems != 0)
5077 moff = __btf_member_bit_offset(t, member) / 8;
5081 /* Only allow structure for now, can be relaxed for
5082 * other types later.
5084 t = btf_type_skip_modifiers(btf, array_elem->type,
5086 if (!btf_type_is_struct(t))
5089 off = (off - moff) % t->size;
5093 bpf_log(log, "access beyond struct %s at off %u size %u\n",
5098 for_each_member(i, t, member) {
5099 /* offset of the field in bytes */
5100 moff = __btf_member_bit_offset(t, member) / 8;
5101 if (off + size <= moff)
5102 /* won't find anything, field is already too far */
5105 if (__btf_member_bitfield_size(t, member)) {
5106 u32 end_bit = __btf_member_bit_offset(t, member) +
5107 __btf_member_bitfield_size(t, member);
5109 /* off <= moff instead of off == moff because clang
5110 * does not generate a BTF member for anonymous
5111 * bitfield like the ":16" here:
5118 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
5121 /* off may be accessing a following member
5125 * Doing partial access at either end of this
5126 * bitfield. Continue on this case also to
5127 * treat it as not accessing this bitfield
5128 * and eventually error out as field not
5129 * found to keep it simple.
5130 * It could be relaxed if there was a legit
5131 * partial access case later.
5136 /* In case of "off" is pointing to holes of a struct */
5140 /* type of the field */
5142 mtype = btf_type_by_id(btf, member->type);
5143 mname = __btf_name_by_offset(btf, member->name_off);
5145 mtype = __btf_resolve_size(btf, mtype, &msize,
5146 &elem_type, &elem_id, &total_nelems,
5148 if (IS_ERR(mtype)) {
5149 bpf_log(log, "field %s doesn't have size\n", mname);
5153 mtrue_end = moff + msize;
5154 if (off >= mtrue_end)
5155 /* no overlap with member, keep iterating */
5158 if (btf_type_is_array(mtype)) {
5161 /* __btf_resolve_size() above helps to
5162 * linearize a multi-dimensional array.
5164 * The logic here is treating an array
5165 * in a struct as the following way:
5168 * struct inner array[2][2];
5174 * struct inner array_elem0;
5175 * struct inner array_elem1;
5176 * struct inner array_elem2;
5177 * struct inner array_elem3;
5180 * When accessing outer->array[1][0], it moves
5181 * moff to "array_elem2", set mtype to
5182 * "struct inner", and msize also becomes
5183 * sizeof(struct inner). Then most of the
5184 * remaining logic will fall through without
5185 * caring the current member is an array or
5188 * Unlike mtype/msize/moff, mtrue_end does not
5189 * change. The naming difference ("_true") tells
5190 * that it is not always corresponding to
5191 * the current mtype/msize/moff.
5192 * It is the true end of the current
5193 * member (i.e. array in this case). That
5194 * will allow an int array to be accessed like
5196 * i.e. allow access beyond the size of
5197 * the array's element as long as it is
5198 * within the mtrue_end boundary.
5201 /* skip empty array */
5202 if (moff == mtrue_end)
5205 msize /= total_nelems;
5206 elem_idx = (off - moff) / msize;
5207 moff += elem_idx * msize;
5212 /* the 'off' we're looking for is either equal to start
5213 * of this field or inside of this struct
5215 if (btf_type_is_struct(mtype)) {
5216 /* our field must be inside that union or struct */
5219 /* return if the offset matches the member offset */
5225 /* adjust offset we're looking for */
5230 if (btf_type_is_ptr(mtype)) {
5231 const struct btf_type *stype;
5234 if (msize != size || off != moff) {
5236 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
5237 mname, moff, tname, off, size);
5240 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
5241 if (btf_type_is_struct(stype)) {
5247 /* Allow more flexible access within an int as long as
5248 * it is within mtrue_end.
5249 * Since mtrue_end could be the end of an array,
5250 * that also allows using an array of int as a scratch
5251 * space. e.g. skb->cb[].
5253 if (off + size > mtrue_end) {
5255 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
5256 mname, mtrue_end, tname, off, size);
5262 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
5266 int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
5267 const struct btf_type *t, int off, int size,
5268 enum bpf_access_type atype __maybe_unused,
5275 err = btf_struct_walk(log, btf, t, off, size, &id);
5279 /* If we found the pointer or scalar on t+off,
5283 return PTR_TO_BTF_ID;
5285 return SCALAR_VALUE;
5287 /* We found nested struct, so continue the search
5288 * by diving in it. At this point the offset is
5289 * aligned with the new type, so set it to 0.
5291 t = btf_type_by_id(btf, id);
5295 /* It's either error or unknown return value..
5298 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
5307 /* Check that two BTF types, each specified as an BTF object + id, are exactly
5308 * the same. Trivial ID check is not enough due to module BTFs, because we can
5309 * end up with two different module BTFs, but IDs point to the common type in
5312 static bool btf_types_are_same(const struct btf *btf1, u32 id1,
5313 const struct btf *btf2, u32 id2)
5319 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
5322 bool btf_struct_ids_match(struct bpf_verifier_log *log,
5323 const struct btf *btf, u32 id, int off,
5324 const struct btf *need_btf, u32 need_type_id)
5326 const struct btf_type *type;
5329 /* Are we already done? */
5330 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
5334 type = btf_type_by_id(btf, id);
5337 err = btf_struct_walk(log, btf, type, off, 1, &id);
5338 if (err != WALK_STRUCT)
5341 /* We found nested struct object. If it matches
5342 * the requested ID, we're done. Otherwise let's
5343 * continue the search with offset 0 in the new
5346 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
5354 static int __get_type_size(struct btf *btf, u32 btf_id,
5355 const struct btf_type **bad_type)
5357 const struct btf_type *t;
5362 t = btf_type_by_id(btf, btf_id);
5363 while (t && btf_type_is_modifier(t))
5364 t = btf_type_by_id(btf, t->type);
5366 *bad_type = btf_type_by_id(btf, 0);
5369 if (btf_type_is_ptr(t))
5370 /* kernel size of pointer. Not BPF's size of pointer*/
5371 return sizeof(void *);
5372 if (btf_type_is_int(t) || btf_type_is_enum(t))
5378 int btf_distill_func_proto(struct bpf_verifier_log *log,
5380 const struct btf_type *func,
5382 struct btf_func_model *m)
5384 const struct btf_param *args;
5385 const struct btf_type *t;
5390 /* BTF function prototype doesn't match the verifier types.
5391 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
5393 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
5396 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
5399 args = (const struct btf_param *)(func + 1);
5400 nargs = btf_type_vlen(func);
5401 if (nargs >= MAX_BPF_FUNC_ARGS) {
5403 "The function %s has %d arguments. Too many.\n",
5407 ret = __get_type_size(btf, func->type, &t);
5410 "The function %s return type %s is unsupported.\n",
5411 tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
5416 for (i = 0; i < nargs; i++) {
5417 if (i == nargs - 1 && args[i].type == 0) {
5419 "The function %s with variable args is unsupported.\n",
5423 ret = __get_type_size(btf, args[i].type, &t);
5426 "The function %s arg%d type %s is unsupported.\n",
5427 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
5432 "The function %s has malformed void argument.\n",
5436 m->arg_size[i] = ret;
5442 /* Compare BTFs of two functions assuming only scalars and pointers to context.
5443 * t1 points to BTF_KIND_FUNC in btf1
5444 * t2 points to BTF_KIND_FUNC in btf2
5446 * EINVAL - function prototype mismatch
5447 * EFAULT - verifier bug
5448 * 0 - 99% match. The last 1% is validated by the verifier.
5450 static int btf_check_func_type_match(struct bpf_verifier_log *log,
5451 struct btf *btf1, const struct btf_type *t1,
5452 struct btf *btf2, const struct btf_type *t2)
5454 const struct btf_param *args1, *args2;
5455 const char *fn1, *fn2, *s1, *s2;
5456 u32 nargs1, nargs2, i;
5458 fn1 = btf_name_by_offset(btf1, t1->name_off);
5459 fn2 = btf_name_by_offset(btf2, t2->name_off);
5461 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
5462 bpf_log(log, "%s() is not a global function\n", fn1);
5465 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
5466 bpf_log(log, "%s() is not a global function\n", fn2);
5470 t1 = btf_type_by_id(btf1, t1->type);
5471 if (!t1 || !btf_type_is_func_proto(t1))
5473 t2 = btf_type_by_id(btf2, t2->type);
5474 if (!t2 || !btf_type_is_func_proto(t2))
5477 args1 = (const struct btf_param *)(t1 + 1);
5478 nargs1 = btf_type_vlen(t1);
5479 args2 = (const struct btf_param *)(t2 + 1);
5480 nargs2 = btf_type_vlen(t2);
5482 if (nargs1 != nargs2) {
5483 bpf_log(log, "%s() has %d args while %s() has %d args\n",
5484 fn1, nargs1, fn2, nargs2);
5488 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5489 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5490 if (t1->info != t2->info) {
5492 "Return type %s of %s() doesn't match type %s of %s()\n",
5493 btf_type_str(t1), fn1,
5494 btf_type_str(t2), fn2);
5498 for (i = 0; i < nargs1; i++) {
5499 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
5500 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
5502 if (t1->info != t2->info) {
5503 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
5504 i, fn1, btf_type_str(t1),
5505 fn2, btf_type_str(t2));
5508 if (btf_type_has_size(t1) && t1->size != t2->size) {
5510 "arg%d in %s() has size %d while %s() has %d\n",
5516 /* global functions are validated with scalars and pointers
5517 * to context only. And only global functions can be replaced.
5518 * Hence type check only those types.
5520 if (btf_type_is_int(t1) || btf_type_is_enum(t1))
5522 if (!btf_type_is_ptr(t1)) {
5524 "arg%d in %s() has unrecognized type\n",
5528 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5529 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5530 if (!btf_type_is_struct(t1)) {
5532 "arg%d in %s() is not a pointer to context\n",
5536 if (!btf_type_is_struct(t2)) {
5538 "arg%d in %s() is not a pointer to context\n",
5542 /* This is an optional check to make program writing easier.
5543 * Compare names of structs and report an error to the user.
5544 * btf_prepare_func_args() already checked that t2 struct
5545 * is a context type. btf_prepare_func_args() will check
5546 * later that t1 struct is a context type as well.
5548 s1 = btf_name_by_offset(btf1, t1->name_off);
5549 s2 = btf_name_by_offset(btf2, t2->name_off);
5550 if (strcmp(s1, s2)) {
5552 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
5553 i, fn1, s1, fn2, s2);
5560 /* Compare BTFs of given program with BTF of target program */
5561 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
5562 struct btf *btf2, const struct btf_type *t2)
5564 struct btf *btf1 = prog->aux->btf;
5565 const struct btf_type *t1;
5568 if (!prog->aux->func_info) {
5569 bpf_log(log, "Program extension requires BTF\n");
5573 btf_id = prog->aux->func_info[0].type_id;
5577 t1 = btf_type_by_id(btf1, btf_id);
5578 if (!t1 || !btf_type_is_func(t1))
5581 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
5584 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
5586 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
5587 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
5588 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
5592 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
5593 static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
5594 const struct btf *btf,
5595 const struct btf_type *t, int rec)
5597 const struct btf_type *member_type;
5598 const struct btf_member *member;
5601 if (!btf_type_is_struct(t))
5604 for_each_member(i, t, member) {
5605 const struct btf_array *array;
5607 member_type = btf_type_skip_modifiers(btf, member->type, NULL);
5608 if (btf_type_is_struct(member_type)) {
5610 bpf_log(log, "max struct nesting depth exceeded\n");
5613 if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
5617 if (btf_type_is_array(member_type)) {
5618 array = btf_type_array(member_type);
5621 member_type = btf_type_skip_modifiers(btf, array->type, NULL);
5622 if (!btf_type_is_scalar(member_type))
5626 if (!btf_type_is_scalar(member_type))
5632 static int btf_check_func_arg_match(struct bpf_verifier_env *env,
5633 const struct btf *btf, u32 func_id,
5634 struct bpf_reg_state *regs,
5637 struct bpf_verifier_log *log = &env->log;
5638 bool is_kfunc = btf_is_kernel(btf);
5639 const char *func_name, *ref_tname;
5640 const struct btf_type *t, *ref_t;
5641 const struct btf_param *args;
5642 u32 i, nargs, ref_id;
5644 t = btf_type_by_id(btf, func_id);
5645 if (!t || !btf_type_is_func(t)) {
5646 /* These checks were already done by the verifier while loading
5647 * struct bpf_func_info or in add_kfunc_call().
5649 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
5653 func_name = btf_name_by_offset(btf, t->name_off);
5655 t = btf_type_by_id(btf, t->type);
5656 if (!t || !btf_type_is_func_proto(t)) {
5657 bpf_log(log, "Invalid BTF of func %s\n", func_name);
5660 args = (const struct btf_param *)(t + 1);
5661 nargs = btf_type_vlen(t);
5662 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5663 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
5664 MAX_BPF_FUNC_REG_ARGS);
5668 /* check that BTF function arguments match actual types that the
5671 for (i = 0; i < nargs; i++) {
5673 struct bpf_reg_state *reg = ®s[regno];
5675 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5676 if (btf_type_is_scalar(t)) {
5677 if (reg->type == SCALAR_VALUE)
5679 bpf_log(log, "R%d is not a scalar\n", regno);
5683 if (!btf_type_is_ptr(t)) {
5684 bpf_log(log, "Unrecognized arg#%d type %s\n",
5685 i, btf_type_str(t));
5689 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
5690 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
5691 if (btf_get_prog_ctx_type(log, btf, t,
5692 env->prog->type, i)) {
5693 /* If function expects ctx type in BTF check that caller
5694 * is passing PTR_TO_CTX.
5696 if (reg->type != PTR_TO_CTX) {
5698 "arg#%d expected pointer to ctx, but got %s\n",
5699 i, btf_type_str(t));
5702 if (check_ptr_off_reg(env, reg, regno))
5704 } else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
5705 (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
5706 const struct btf_type *reg_ref_t;
5707 const struct btf *reg_btf;
5708 const char *reg_ref_tname;
5711 if (!btf_type_is_struct(ref_t)) {
5712 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
5713 func_name, i, btf_type_str(ref_t),
5718 if (reg->type == PTR_TO_BTF_ID) {
5720 reg_ref_id = reg->btf_id;
5722 reg_btf = btf_vmlinux;
5723 reg_ref_id = *reg2btf_ids[base_type(reg->type)];
5726 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
5728 reg_ref_tname = btf_name_by_offset(reg_btf,
5729 reg_ref_t->name_off);
5730 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
5731 reg->off, btf, ref_id)) {
5732 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
5734 btf_type_str(ref_t), ref_tname,
5735 regno, btf_type_str(reg_ref_t),
5739 } else if (ptr_to_mem_ok) {
5740 const struct btf_type *resolve_ret;
5744 /* Permit pointer to mem, but only when argument
5745 * type is pointer to scalar, or struct composed
5746 * (recursively) of scalars.
5748 if (!btf_type_is_scalar(ref_t) &&
5749 !__btf_type_is_scalar_struct(log, btf, ref_t, 0)) {
5751 "arg#%d pointer type %s %s must point to scalar or struct with scalar\n",
5752 i, btf_type_str(ref_t), ref_tname);
5757 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
5758 if (IS_ERR(resolve_ret)) {
5760 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5761 i, btf_type_str(ref_t), ref_tname,
5762 PTR_ERR(resolve_ret));
5766 if (check_mem_reg(env, reg, regno, type_size))
5769 bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
5770 is_kfunc ? "kernel " : "", func_name, func_id);
5778 /* Compare BTF of a function with given bpf_reg_state.
5780 * EFAULT - there is a verifier bug. Abort verification.
5781 * EINVAL - there is a type mismatch or BTF is not available.
5782 * 0 - BTF matches with what bpf_reg_state expects.
5783 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
5785 int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
5786 struct bpf_reg_state *regs)
5788 struct bpf_prog *prog = env->prog;
5789 struct btf *btf = prog->aux->btf;
5794 if (!prog->aux->func_info)
5797 btf_id = prog->aux->func_info[subprog].type_id;
5801 if (prog->aux->func_info_aux[subprog].unreliable)
5804 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
5805 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global);
5807 /* Compiler optimizations can remove arguments from static functions
5808 * or mismatched type can be passed into a global function.
5809 * In such cases mark the function as unreliable from BTF point of view.
5812 prog->aux->func_info_aux[subprog].unreliable = true;
5816 int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
5817 const struct btf *btf, u32 func_id,
5818 struct bpf_reg_state *regs)
5820 return btf_check_func_arg_match(env, btf, func_id, regs, true);
5823 /* Convert BTF of a function into bpf_reg_state if possible
5825 * EFAULT - there is a verifier bug. Abort verification.
5826 * EINVAL - cannot convert BTF.
5827 * 0 - Successfully converted BTF into bpf_reg_state
5828 * (either PTR_TO_CTX or SCALAR_VALUE).
5830 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
5831 struct bpf_reg_state *regs)
5833 struct bpf_verifier_log *log = &env->log;
5834 struct bpf_prog *prog = env->prog;
5835 enum bpf_prog_type prog_type = prog->type;
5836 struct btf *btf = prog->aux->btf;
5837 const struct btf_param *args;
5838 const struct btf_type *t, *ref_t;
5839 u32 i, nargs, btf_id;
5842 if (!prog->aux->func_info ||
5843 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
5844 bpf_log(log, "Verifier bug\n");
5848 btf_id = prog->aux->func_info[subprog].type_id;
5850 bpf_log(log, "Global functions need valid BTF\n");
5854 t = btf_type_by_id(btf, btf_id);
5855 if (!t || !btf_type_is_func(t)) {
5856 /* These checks were already done by the verifier while loading
5857 * struct bpf_func_info
5859 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
5863 tname = btf_name_by_offset(btf, t->name_off);
5865 if (log->level & BPF_LOG_LEVEL)
5866 bpf_log(log, "Validating %s() func#%d...\n",
5869 if (prog->aux->func_info_aux[subprog].unreliable) {
5870 bpf_log(log, "Verifier bug in function %s()\n", tname);
5873 if (prog_type == BPF_PROG_TYPE_EXT)
5874 prog_type = prog->aux->dst_prog->type;
5876 t = btf_type_by_id(btf, t->type);
5877 if (!t || !btf_type_is_func_proto(t)) {
5878 bpf_log(log, "Invalid type of function %s()\n", tname);
5881 args = (const struct btf_param *)(t + 1);
5882 nargs = btf_type_vlen(t);
5883 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5884 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
5885 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
5888 /* check that function returns int */
5889 t = btf_type_by_id(btf, t->type);
5890 while (btf_type_is_modifier(t))
5891 t = btf_type_by_id(btf, t->type);
5892 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) {
5894 "Global function %s() doesn't return scalar. Only those are supported.\n",
5898 /* Convert BTF function arguments into verifier types.
5899 * Only PTR_TO_CTX and SCALAR are supported atm.
5901 for (i = 0; i < nargs; i++) {
5902 struct bpf_reg_state *reg = ®s[i + 1];
5904 t = btf_type_by_id(btf, args[i].type);
5905 while (btf_type_is_modifier(t))
5906 t = btf_type_by_id(btf, t->type);
5907 if (btf_type_is_int(t) || btf_type_is_enum(t)) {
5908 reg->type = SCALAR_VALUE;
5911 if (btf_type_is_ptr(t)) {
5912 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
5913 reg->type = PTR_TO_CTX;
5917 t = btf_type_skip_modifiers(btf, t->type, NULL);
5919 ref_t = btf_resolve_size(btf, t, ®->mem_size);
5920 if (IS_ERR(ref_t)) {
5922 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5923 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
5928 reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
5929 reg->id = ++env->id_gen;
5933 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
5934 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname);
5940 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
5941 struct btf_show *show)
5943 const struct btf_type *t = btf_type_by_id(btf, type_id);
5946 memset(&show->state, 0, sizeof(show->state));
5947 memset(&show->obj, 0, sizeof(show->obj));
5949 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
5952 static void btf_seq_show(struct btf_show *show, const char *fmt,
5955 seq_vprintf((struct seq_file *)show->target, fmt, args);
5958 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
5959 void *obj, struct seq_file *m, u64 flags)
5961 struct btf_show sseq;
5964 sseq.showfn = btf_seq_show;
5967 btf_type_show(btf, type_id, obj, &sseq);
5969 return sseq.state.status;
5972 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
5975 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
5976 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
5977 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
5980 struct btf_show_snprintf {
5981 struct btf_show show;
5982 int len_left; /* space left in string */
5983 int len; /* length we would have written */
5986 static void btf_snprintf_show(struct btf_show *show, const char *fmt,
5989 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
5992 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
5995 ssnprintf->len_left = 0;
5996 ssnprintf->len = len;
5997 } else if (len > ssnprintf->len_left) {
5998 /* no space, drive on to get length we would have written */
5999 ssnprintf->len_left = 0;
6000 ssnprintf->len += len;
6002 ssnprintf->len_left -= len;
6003 ssnprintf->len += len;
6004 show->target += len;
6008 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
6009 char *buf, int len, u64 flags)
6011 struct btf_show_snprintf ssnprintf;
6013 ssnprintf.show.target = buf;
6014 ssnprintf.show.flags = flags;
6015 ssnprintf.show.showfn = btf_snprintf_show;
6016 ssnprintf.len_left = len;
6019 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
6021 /* If we encontered an error, return it. */
6022 if (ssnprintf.show.state.status)
6023 return ssnprintf.show.state.status;
6025 /* Otherwise return length we would have written */
6026 return ssnprintf.len;
6029 #ifdef CONFIG_PROC_FS
6030 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
6032 const struct btf *btf = filp->private_data;
6034 seq_printf(m, "btf_id:\t%u\n", btf->id);
6038 static int btf_release(struct inode *inode, struct file *filp)
6040 btf_put(filp->private_data);
6044 const struct file_operations btf_fops = {
6045 #ifdef CONFIG_PROC_FS
6046 .show_fdinfo = bpf_btf_show_fdinfo,
6048 .release = btf_release,
6051 static int __btf_new_fd(struct btf *btf)
6053 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
6056 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
6061 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
6062 attr->btf_size, attr->btf_log_level,
6063 u64_to_user_ptr(attr->btf_log_buf),
6064 attr->btf_log_size);
6066 return PTR_ERR(btf);
6068 ret = btf_alloc_id(btf);
6075 * The BTF ID is published to the userspace.
6076 * All BTF free must go through call_rcu() from
6077 * now on (i.e. free by calling btf_put()).
6080 ret = __btf_new_fd(btf);
6087 struct btf *btf_get_by_fd(int fd)
6095 return ERR_PTR(-EBADF);
6097 if (f.file->f_op != &btf_fops) {
6099 return ERR_PTR(-EINVAL);
6102 btf = f.file->private_data;
6103 refcount_inc(&btf->refcnt);
6109 int btf_get_info_by_fd(const struct btf *btf,
6110 const union bpf_attr *attr,
6111 union bpf_attr __user *uattr)
6113 struct bpf_btf_info __user *uinfo;
6114 struct bpf_btf_info info;
6115 u32 info_copy, btf_copy;
6118 u32 uinfo_len, uname_len, name_len;
6121 uinfo = u64_to_user_ptr(attr->info.info);
6122 uinfo_len = attr->info.info_len;
6124 info_copy = min_t(u32, uinfo_len, sizeof(info));
6125 memset(&info, 0, sizeof(info));
6126 if (copy_from_user(&info, uinfo, info_copy))
6130 ubtf = u64_to_user_ptr(info.btf);
6131 btf_copy = min_t(u32, btf->data_size, info.btf_size);
6132 if (copy_to_user(ubtf, btf->data, btf_copy))
6134 info.btf_size = btf->data_size;
6136 info.kernel_btf = btf->kernel_btf;
6138 uname = u64_to_user_ptr(info.name);
6139 uname_len = info.name_len;
6140 if (!uname ^ !uname_len)
6143 name_len = strlen(btf->name);
6144 info.name_len = name_len;
6147 if (uname_len >= name_len + 1) {
6148 if (copy_to_user(uname, btf->name, name_len + 1))
6153 if (copy_to_user(uname, btf->name, uname_len - 1))
6155 if (put_user(zero, uname + uname_len - 1))
6157 /* let user-space know about too short buffer */
6162 if (copy_to_user(uinfo, &info, info_copy) ||
6163 put_user(info_copy, &uattr->info.info_len))
6169 int btf_get_fd_by_id(u32 id)
6175 btf = idr_find(&btf_idr, id);
6176 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
6177 btf = ERR_PTR(-ENOENT);
6181 return PTR_ERR(btf);
6183 fd = __btf_new_fd(btf);
6190 u32 btf_obj_id(const struct btf *btf)
6195 bool btf_is_kernel(const struct btf *btf)
6197 return btf->kernel_btf;
6200 bool btf_is_module(const struct btf *btf)
6202 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
6205 static int btf_id_cmp_func(const void *a, const void *b)
6207 const int *pa = a, *pb = b;
6212 bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
6214 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
6218 BTF_MODULE_F_LIVE = (1 << 0),
6221 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6223 struct list_head list;
6224 struct module *module;
6226 struct bin_attribute *sysfs_attr;
6230 static LIST_HEAD(btf_modules);
6231 static DEFINE_MUTEX(btf_module_mutex);
6234 btf_module_read(struct file *file, struct kobject *kobj,
6235 struct bin_attribute *bin_attr,
6236 char *buf, loff_t off, size_t len)
6238 const struct btf *btf = bin_attr->private;
6240 memcpy(buf, btf->data + off, len);
6244 static void purge_cand_cache(struct btf *btf);
6246 static int btf_module_notify(struct notifier_block *nb, unsigned long op,
6249 struct btf_module *btf_mod, *tmp;
6250 struct module *mod = module;
6254 if (mod->btf_data_size == 0 ||
6255 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
6256 op != MODULE_STATE_GOING))
6260 case MODULE_STATE_COMING:
6261 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
6266 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
6268 pr_warn("failed to validate module [%s] BTF: %ld\n",
6269 mod->name, PTR_ERR(btf));
6274 err = btf_alloc_id(btf);
6281 purge_cand_cache(NULL);
6282 mutex_lock(&btf_module_mutex);
6283 btf_mod->module = module;
6285 list_add(&btf_mod->list, &btf_modules);
6286 mutex_unlock(&btf_module_mutex);
6288 if (IS_ENABLED(CONFIG_SYSFS)) {
6289 struct bin_attribute *attr;
6291 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
6295 sysfs_bin_attr_init(attr);
6296 attr->attr.name = btf->name;
6297 attr->attr.mode = 0444;
6298 attr->size = btf->data_size;
6299 attr->private = btf;
6300 attr->read = btf_module_read;
6302 err = sysfs_create_bin_file(btf_kobj, attr);
6304 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
6311 btf_mod->sysfs_attr = attr;
6315 case MODULE_STATE_LIVE:
6316 mutex_lock(&btf_module_mutex);
6317 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6318 if (btf_mod->module != module)
6321 btf_mod->flags |= BTF_MODULE_F_LIVE;
6324 mutex_unlock(&btf_module_mutex);
6326 case MODULE_STATE_GOING:
6327 mutex_lock(&btf_module_mutex);
6328 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6329 if (btf_mod->module != module)
6332 list_del(&btf_mod->list);
6333 if (btf_mod->sysfs_attr)
6334 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
6335 purge_cand_cache(btf_mod->btf);
6336 btf_put(btf_mod->btf);
6337 kfree(btf_mod->sysfs_attr);
6341 mutex_unlock(&btf_module_mutex);
6345 return notifier_from_errno(err);
6348 static struct notifier_block btf_module_nb = {
6349 .notifier_call = btf_module_notify,
6352 static int __init btf_module_init(void)
6354 register_module_notifier(&btf_module_nb);
6358 fs_initcall(btf_module_init);
6359 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6361 struct module *btf_try_get_module(const struct btf *btf)
6363 struct module *res = NULL;
6364 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6365 struct btf_module *btf_mod, *tmp;
6367 mutex_lock(&btf_module_mutex);
6368 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6369 if (btf_mod->btf != btf)
6372 /* We must only consider module whose __init routine has
6373 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
6374 * which is set from the notifier callback for
6375 * MODULE_STATE_LIVE.
6377 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
6378 res = btf_mod->module;
6382 mutex_unlock(&btf_module_mutex);
6388 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
6396 if (name_sz <= 1 || name[name_sz - 1])
6399 btf = bpf_get_btf_vmlinux();
6401 return PTR_ERR(btf);
6403 ret = btf_find_by_name_kind(btf, name, kind);
6404 /* ret is never zero, since btf_find_by_name_kind returns
6405 * positive btf_id or negative error.
6408 struct btf *mod_btf;
6411 /* If name is not found in vmlinux's BTF then search in module's BTFs */
6412 spin_lock_bh(&btf_idr_lock);
6413 idr_for_each_entry(&btf_idr, mod_btf, id) {
6414 if (!btf_is_module(mod_btf))
6416 /* linear search could be slow hence unlock/lock
6417 * the IDR to avoiding holding it for too long
6420 spin_unlock_bh(&btf_idr_lock);
6421 ret = btf_find_by_name_kind(mod_btf, name, kind);
6425 btf_obj_fd = __btf_new_fd(mod_btf);
6426 if (btf_obj_fd < 0) {
6430 return ret | (((u64)btf_obj_fd) << 32);
6432 spin_lock_bh(&btf_idr_lock);
6435 spin_unlock_bh(&btf_idr_lock);
6440 const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
6441 .func = bpf_btf_find_by_name_kind,
6443 .ret_type = RET_INTEGER,
6444 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
6445 .arg2_type = ARG_CONST_SIZE,
6446 .arg3_type = ARG_ANYTHING,
6447 .arg4_type = ARG_ANYTHING,
6450 BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
6451 #define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
6452 BTF_TRACING_TYPE_xxx
6453 #undef BTF_TRACING_TYPE
6455 /* BTF ID set registration API for modules */
6457 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6459 void register_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
6460 struct kfunc_btf_id_set *s)
6462 mutex_lock(&l->mutex);
6463 list_add(&s->list, &l->list);
6464 mutex_unlock(&l->mutex);
6466 EXPORT_SYMBOL_GPL(register_kfunc_btf_id_set);
6468 void unregister_kfunc_btf_id_set(struct kfunc_btf_id_list *l,
6469 struct kfunc_btf_id_set *s)
6471 mutex_lock(&l->mutex);
6472 list_del_init(&s->list);
6473 mutex_unlock(&l->mutex);
6475 EXPORT_SYMBOL_GPL(unregister_kfunc_btf_id_set);
6477 bool bpf_check_mod_kfunc_call(struct kfunc_btf_id_list *klist, u32 kfunc_id,
6478 struct module *owner)
6480 struct kfunc_btf_id_set *s;
6482 mutex_lock(&klist->mutex);
6483 list_for_each_entry(s, &klist->list, list) {
6484 if (s->owner == owner && btf_id_set_contains(s->set, kfunc_id)) {
6485 mutex_unlock(&klist->mutex);
6489 mutex_unlock(&klist->mutex);
6493 #define DEFINE_KFUNC_BTF_ID_LIST(name) \
6494 struct kfunc_btf_id_list name = { LIST_HEAD_INIT(name.list), \
6495 __MUTEX_INITIALIZER(name.mutex) }; \
6496 EXPORT_SYMBOL_GPL(name)
6498 DEFINE_KFUNC_BTF_ID_LIST(bpf_tcp_ca_kfunc_list);
6499 DEFINE_KFUNC_BTF_ID_LIST(prog_test_kfunc_list);
6503 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
6504 const struct btf *targ_btf, __u32 targ_id)
6509 static bool bpf_core_is_flavor_sep(const char *s)
6511 /* check X___Y name pattern, where X and Y are not underscores */
6512 return s[0] != '_' && /* X */
6513 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
6514 s[4] != '_'; /* Y */
6517 size_t bpf_core_essential_name_len(const char *name)
6519 size_t n = strlen(name);
6522 for (i = n - 5; i >= 0; i--) {
6523 if (bpf_core_is_flavor_sep(name + i))
6529 struct bpf_cand_cache {
6535 const struct btf *btf;
6540 static void bpf_free_cands(struct bpf_cand_cache *cands)
6543 /* empty candidate array was allocated on stack */
6548 static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
6554 #define VMLINUX_CAND_CACHE_SIZE 31
6555 static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
6557 #define MODULE_CAND_CACHE_SIZE 31
6558 static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
6560 static DEFINE_MUTEX(cand_cache_mutex);
6562 static void __print_cand_cache(struct bpf_verifier_log *log,
6563 struct bpf_cand_cache **cache,
6566 struct bpf_cand_cache *cc;
6569 for (i = 0; i < cache_size; i++) {
6573 bpf_log(log, "[%d]%s(", i, cc->name);
6574 for (j = 0; j < cc->cnt; j++) {
6575 bpf_log(log, "%d", cc->cands[j].id);
6576 if (j < cc->cnt - 1)
6579 bpf_log(log, "), ");
6583 static void print_cand_cache(struct bpf_verifier_log *log)
6585 mutex_lock(&cand_cache_mutex);
6586 bpf_log(log, "vmlinux_cand_cache:");
6587 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
6588 bpf_log(log, "\nmodule_cand_cache:");
6589 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
6591 mutex_unlock(&cand_cache_mutex);
6594 static u32 hash_cands(struct bpf_cand_cache *cands)
6596 return jhash(cands->name, cands->name_len, 0);
6599 static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
6600 struct bpf_cand_cache **cache,
6603 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
6605 if (cc && cc->name_len == cands->name_len &&
6606 !strncmp(cc->name, cands->name, cands->name_len))
6611 static size_t sizeof_cands(int cnt)
6613 return offsetof(struct bpf_cand_cache, cands[cnt]);
6616 static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
6617 struct bpf_cand_cache **cache,
6620 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
6623 bpf_free_cands_from_cache(*cc);
6626 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
6628 bpf_free_cands(cands);
6629 return ERR_PTR(-ENOMEM);
6631 /* strdup the name, since it will stay in cache.
6632 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
6634 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
6635 bpf_free_cands(cands);
6636 if (!new_cands->name) {
6638 return ERR_PTR(-ENOMEM);
6644 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6645 static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
6648 struct bpf_cand_cache *cc;
6651 for (i = 0; i < cache_size; i++) {
6656 /* when new module is loaded purge all of module_cand_cache,
6657 * since new module might have candidates with the name
6658 * that matches cached cands.
6660 bpf_free_cands_from_cache(cc);
6664 /* when module is unloaded purge cache entries
6665 * that match module's btf
6667 for (j = 0; j < cc->cnt; j++)
6668 if (cc->cands[j].btf == btf) {
6669 bpf_free_cands_from_cache(cc);
6677 static void purge_cand_cache(struct btf *btf)
6679 mutex_lock(&cand_cache_mutex);
6680 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
6681 mutex_unlock(&cand_cache_mutex);
6685 static struct bpf_cand_cache *
6686 bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
6689 struct bpf_cand_cache *new_cands;
6690 const struct btf_type *t;
6691 const char *targ_name;
6692 size_t targ_essent_len;
6695 n = btf_nr_types(targ_btf);
6696 for (i = targ_start_id; i < n; i++) {
6697 t = btf_type_by_id(targ_btf, i);
6698 if (btf_kind(t) != cands->kind)
6701 targ_name = btf_name_by_offset(targ_btf, t->name_off);
6705 /* the resched point is before strncmp to make sure that search
6706 * for non-existing name will have a chance to schedule().
6710 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
6713 targ_essent_len = bpf_core_essential_name_len(targ_name);
6714 if (targ_essent_len != cands->name_len)
6717 /* most of the time there is only one candidate for a given kind+name pair */
6718 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
6720 bpf_free_cands(cands);
6721 return ERR_PTR(-ENOMEM);
6724 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
6725 bpf_free_cands(cands);
6727 cands->cands[cands->cnt].btf = targ_btf;
6728 cands->cands[cands->cnt].id = i;
6734 static struct bpf_cand_cache *
6735 bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
6737 struct bpf_cand_cache *cands, *cc, local_cand = {};
6738 const struct btf *local_btf = ctx->btf;
6739 const struct btf_type *local_type;
6740 const struct btf *main_btf;
6741 size_t local_essent_len;
6742 struct btf *mod_btf;
6746 main_btf = bpf_get_btf_vmlinux();
6747 if (IS_ERR(main_btf))
6748 return ERR_CAST(main_btf);
6750 local_type = btf_type_by_id(local_btf, local_type_id);
6752 return ERR_PTR(-EINVAL);
6754 name = btf_name_by_offset(local_btf, local_type->name_off);
6755 if (str_is_empty(name))
6756 return ERR_PTR(-EINVAL);
6757 local_essent_len = bpf_core_essential_name_len(name);
6759 cands = &local_cand;
6761 cands->kind = btf_kind(local_type);
6762 cands->name_len = local_essent_len;
6764 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
6765 /* cands is a pointer to stack here */
6772 /* Attempt to find target candidates in vmlinux BTF first */
6773 cands = bpf_core_add_cands(cands, main_btf, 1);
6775 return ERR_CAST(cands);
6777 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
6779 /* populate cache even when cands->cnt == 0 */
6780 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
6782 return ERR_CAST(cc);
6784 /* if vmlinux BTF has any candidate, don't go for module BTFs */
6789 /* cands is a pointer to stack here and cands->cnt == 0 */
6790 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
6792 /* if cache has it return it even if cc->cnt == 0 */
6795 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
6796 spin_lock_bh(&btf_idr_lock);
6797 idr_for_each_entry(&btf_idr, mod_btf, id) {
6798 if (!btf_is_module(mod_btf))
6800 /* linear search could be slow hence unlock/lock
6801 * the IDR to avoiding holding it for too long
6804 spin_unlock_bh(&btf_idr_lock);
6805 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
6806 if (IS_ERR(cands)) {
6808 return ERR_CAST(cands);
6810 spin_lock_bh(&btf_idr_lock);
6813 spin_unlock_bh(&btf_idr_lock);
6814 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
6815 * or pointer to stack if cands->cnd == 0.
6816 * Copy it into the cache even when cands->cnt == 0 and
6817 * return the result.
6819 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
6822 int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
6823 int relo_idx, void *insn)
6825 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
6826 struct bpf_core_cand_list cands = {};
6827 struct bpf_core_spec *specs;
6830 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
6831 * into arrays of btf_ids of struct fields and array indices.
6833 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
6838 struct bpf_cand_cache *cc;
6841 mutex_lock(&cand_cache_mutex);
6842 cc = bpf_core_find_cands(ctx, relo->type_id);
6844 bpf_log(ctx->log, "target candidate search failed for %d\n",
6850 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
6856 for (i = 0; i < cc->cnt; i++) {
6858 "CO-RE relocating %s %s: found target candidate [%d]\n",
6859 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
6860 cands.cands[i].btf = cc->cands[i].btf;
6861 cands.cands[i].id = cc->cands[i].id;
6863 cands.len = cc->cnt;
6864 /* cand_cache_mutex needs to span the cache lookup and
6865 * copy of btf pointer into bpf_core_cand_list,
6866 * since module can be unloaded while bpf_core_apply_relo_insn
6867 * is working with module's btf.
6871 err = bpf_core_apply_relo_insn((void *)ctx->log, insn, relo->insn_off / 8,
6872 relo, relo_idx, ctx->btf, &cands, specs);
6877 mutex_unlock(&cand_cache_mutex);
6878 if (ctx->log->level & BPF_LOG_LEVEL2)
6879 print_cand_cache(ctx->log);