1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (c) 2018 Facebook */
4 #include <uapi/linux/btf.h>
5 #include <uapi/linux/bpf.h>
6 #include <uapi/linux/bpf_perf_event.h>
7 #include <uapi/linux/types.h>
8 #include <linux/seq_file.h>
9 #include <linux/compiler.h>
10 #include <linux/ctype.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/anon_inodes.h>
14 #include <linux/file.h>
15 #include <linux/uaccess.h>
16 #include <linux/kernel.h>
17 #include <linux/idr.h>
18 #include <linux/sort.h>
19 #include <linux/bpf_verifier.h>
20 #include <linux/btf.h>
21 #include <linux/btf_ids.h>
22 #include <linux/skmsg.h>
23 #include <linux/perf_event.h>
24 #include <linux/bsearch.h>
25 #include <linux/kobject.h>
26 #include <linux/sysfs.h>
28 #include "../tools/lib/bpf/relo_core.h"
30 /* BTF (BPF Type Format) is the meta data format which describes
31 * the data types of BPF program/map. Hence, it basically focus
32 * on the C programming language which the modern BPF is primary
37 * The BTF data is stored under the ".BTF" ELF section
41 * Each 'struct btf_type' object describes a C data type.
42 * Depending on the type it is describing, a 'struct btf_type'
43 * object may be followed by more data. F.e.
44 * To describe an array, 'struct btf_type' is followed by
47 * 'struct btf_type' and any extra data following it are
52 * The BTF type section contains a list of 'struct btf_type' objects.
53 * Each one describes a C type. Recall from the above section
54 * that a 'struct btf_type' object could be immediately followed by extra
55 * data in order to describe some particular C types.
59 * Each btf_type object is identified by a type_id. The type_id
60 * is implicitly implied by the location of the btf_type object in
61 * the BTF type section. The first one has type_id 1. The second
62 * one has type_id 2...etc. Hence, an earlier btf_type has
65 * A btf_type object may refer to another btf_type object by using
66 * type_id (i.e. the "type" in the "struct btf_type").
68 * NOTE that we cannot assume any reference-order.
69 * A btf_type object can refer to an earlier btf_type object
70 * but it can also refer to a later btf_type object.
72 * For example, to describe "const void *". A btf_type
73 * object describing "const" may refer to another btf_type
74 * object describing "void *". This type-reference is done
75 * by specifying type_id:
77 * [1] CONST (anon) type_id=2
78 * [2] PTR (anon) type_id=0
80 * The above is the btf_verifier debug log:
81 * - Each line started with "[?]" is a btf_type object
82 * - [?] is the type_id of the btf_type object.
83 * - CONST/PTR is the BTF_KIND_XXX
84 * - "(anon)" is the name of the type. It just
85 * happens that CONST and PTR has no name.
86 * - type_id=XXX is the 'u32 type' in btf_type
88 * NOTE: "void" has type_id 0
92 * The BTF string section contains the names used by the type section.
93 * Each string is referred by an "offset" from the beginning of the
96 * Each string is '\0' terminated.
98 * The first character in the string section must be '\0'
99 * which is used to mean 'anonymous'. Some btf_type may not
105 * To verify BTF data, two passes are needed.
109 * The first pass is to collect all btf_type objects to
110 * an array: "btf->types".
112 * Depending on the C type that a btf_type is describing,
113 * a btf_type may be followed by extra data. We don't know
114 * how many btf_type is there, and more importantly we don't
115 * know where each btf_type is located in the type section.
117 * Without knowing the location of each type_id, most verifications
118 * cannot be done. e.g. an earlier btf_type may refer to a later
119 * btf_type (recall the "const void *" above), so we cannot
120 * check this type-reference in the first pass.
122 * In the first pass, it still does some verifications (e.g.
123 * checking the name is a valid offset to the string section).
127 * The main focus is to resolve a btf_type that is referring
130 * We have to ensure the referring type:
131 * 1) does exist in the BTF (i.e. in btf->types[])
132 * 2) does not cause a loop:
141 * btf_type_needs_resolve() decides if a btf_type needs
144 * The needs_resolve type implements the "resolve()" ops which
145 * essentially does a DFS and detects backedge.
147 * During resolve (or DFS), different C types have different
148 * "RESOLVED" conditions.
150 * When resolving a BTF_KIND_STRUCT, we need to resolve all its
151 * members because a member is always referring to another
152 * type. A struct's member can be treated as "RESOLVED" if
153 * it is referring to a BTF_KIND_PTR. Otherwise, the
154 * following valid C struct would be rejected:
161 * When resolving a BTF_KIND_PTR, it needs to keep resolving if
162 * it is referring to another BTF_KIND_PTR. Otherwise, we cannot
163 * detect a pointer loop, e.g.:
164 * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR +
166 * +-----------------------------------------+
170 #define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2)
171 #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
172 #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
173 #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
174 #define BITS_ROUNDUP_BYTES(bits) \
175 (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
177 #define BTF_INFO_MASK 0x9f00ffff
178 #define BTF_INT_MASK 0x0fffffff
179 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
180 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
182 /* 16MB for 64k structs and each has 16 members and
183 * a few MB spaces for the string section.
184 * The hard limit is S32_MAX.
186 #define BTF_MAX_SIZE (16 * 1024 * 1024)
188 #define for_each_member_from(i, from, struct_type, member) \
189 for (i = from, member = btf_type_member(struct_type) + from; \
190 i < btf_type_vlen(struct_type); \
193 #define for_each_vsi_from(i, from, struct_type, member) \
194 for (i = from, member = btf_type_var_secinfo(struct_type) + from; \
195 i < btf_type_vlen(struct_type); \
199 DEFINE_SPINLOCK(btf_idr_lock);
201 enum btf_kfunc_hook {
204 BTF_KFUNC_HOOK_STRUCT_OPS,
209 BTF_KFUNC_SET_MAX_CNT = 32,
212 struct btf_kfunc_set_tab {
213 struct btf_id_set *sets[BTF_KFUNC_HOOK_MAX][BTF_KFUNC_TYPE_MAX];
218 struct btf_type **types;
223 struct btf_header hdr;
224 u32 nr_types; /* includes VOID for base BTF */
230 struct btf_kfunc_set_tab *kfunc_set_tab;
232 /* split BTF support */
233 struct btf *base_btf;
234 u32 start_id; /* first type ID in this BTF (0 for base BTF) */
235 u32 start_str_off; /* first string offset (0 for base BTF) */
236 char name[MODULE_NAME_LEN];
240 enum verifier_phase {
245 struct resolve_vertex {
246 const struct btf_type *t;
258 RESOLVE_TBD, /* To Be Determined */
259 RESOLVE_PTR, /* Resolving for Pointer */
260 RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union
265 #define MAX_RESOLVE_DEPTH 32
267 struct btf_sec_info {
272 struct btf_verifier_env {
275 struct resolve_vertex stack[MAX_RESOLVE_DEPTH];
276 struct bpf_verifier_log log;
279 enum verifier_phase phase;
280 enum resolve_mode resolve_mode;
283 static const char * const btf_kind_str[NR_BTF_KINDS] = {
284 [BTF_KIND_UNKN] = "UNKNOWN",
285 [BTF_KIND_INT] = "INT",
286 [BTF_KIND_PTR] = "PTR",
287 [BTF_KIND_ARRAY] = "ARRAY",
288 [BTF_KIND_STRUCT] = "STRUCT",
289 [BTF_KIND_UNION] = "UNION",
290 [BTF_KIND_ENUM] = "ENUM",
291 [BTF_KIND_FWD] = "FWD",
292 [BTF_KIND_TYPEDEF] = "TYPEDEF",
293 [BTF_KIND_VOLATILE] = "VOLATILE",
294 [BTF_KIND_CONST] = "CONST",
295 [BTF_KIND_RESTRICT] = "RESTRICT",
296 [BTF_KIND_FUNC] = "FUNC",
297 [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO",
298 [BTF_KIND_VAR] = "VAR",
299 [BTF_KIND_DATASEC] = "DATASEC",
300 [BTF_KIND_FLOAT] = "FLOAT",
301 [BTF_KIND_DECL_TAG] = "DECL_TAG",
302 [BTF_KIND_TYPE_TAG] = "TYPE_TAG",
305 const char *btf_type_str(const struct btf_type *t)
307 return btf_kind_str[BTF_INFO_KIND(t->info)];
310 /* Chunk size we use in safe copy of data to be shown. */
311 #define BTF_SHOW_OBJ_SAFE_SIZE 32
314 * This is the maximum size of a base type value (equivalent to a
315 * 128-bit int); if we are at the end of our safe buffer and have
316 * less than 16 bytes space we can't be assured of being able
317 * to copy the next type safely, so in such cases we will initiate
320 #define BTF_SHOW_OBJ_BASE_TYPE_SIZE 16
323 #define BTF_SHOW_NAME_SIZE 80
326 * Common data to all BTF show operations. Private show functions can add
327 * their own data to a structure containing a struct btf_show and consult it
328 * in the show callback. See btf_type_show() below.
330 * One challenge with showing nested data is we want to skip 0-valued
331 * data, but in order to figure out whether a nested object is all zeros
332 * we need to walk through it. As a result, we need to make two passes
333 * when handling structs, unions and arrays; the first path simply looks
334 * for nonzero data, while the second actually does the display. The first
335 * pass is signalled by show->state.depth_check being set, and if we
336 * encounter a non-zero value we set show->state.depth_to_show to
337 * the depth at which we encountered it. When we have completed the
338 * first pass, we will know if anything needs to be displayed if
339 * depth_to_show > depth. See btf_[struct,array]_show() for the
340 * implementation of this.
342 * Another problem is we want to ensure the data for display is safe to
343 * access. To support this, the anonymous "struct {} obj" tracks the data
344 * object and our safe copy of it. We copy portions of the data needed
345 * to the object "copy" buffer, but because its size is limited to
346 * BTF_SHOW_OBJ_COPY_LEN bytes, multiple copies may be required as we
347 * traverse larger objects for display.
349 * The various data type show functions all start with a call to
350 * btf_show_start_type() which returns a pointer to the safe copy
351 * of the data needed (or if BTF_SHOW_UNSAFE is specified, to the
352 * raw data itself). btf_show_obj_safe() is responsible for
353 * using copy_from_kernel_nofault() to update the safe data if necessary
354 * as we traverse the object's data. skbuff-like semantics are
357 * - obj.head points to the start of the toplevel object for display
358 * - obj.size is the size of the toplevel object
359 * - obj.data points to the current point in the original data at
360 * which our safe data starts. obj.data will advance as we copy
361 * portions of the data.
363 * In most cases a single copy will suffice, but larger data structures
364 * such as "struct task_struct" will require many copies. The logic in
365 * btf_show_obj_safe() handles the logic that determines if a new
366 * copy_from_kernel_nofault() is needed.
370 void *target; /* target of show operation (seq file, buffer) */
371 void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
372 const struct btf *btf;
373 /* below are used during iteration */
382 int status; /* non-zero for error */
383 const struct btf_type *type;
384 const struct btf_member *member;
385 char name[BTF_SHOW_NAME_SIZE]; /* space for member name/type */
391 u8 safe[BTF_SHOW_OBJ_SAFE_SIZE];
395 struct btf_kind_operations {
396 s32 (*check_meta)(struct btf_verifier_env *env,
397 const struct btf_type *t,
399 int (*resolve)(struct btf_verifier_env *env,
400 const struct resolve_vertex *v);
401 int (*check_member)(struct btf_verifier_env *env,
402 const struct btf_type *struct_type,
403 const struct btf_member *member,
404 const struct btf_type *member_type);
405 int (*check_kflag_member)(struct btf_verifier_env *env,
406 const struct btf_type *struct_type,
407 const struct btf_member *member,
408 const struct btf_type *member_type);
409 void (*log_details)(struct btf_verifier_env *env,
410 const struct btf_type *t);
411 void (*show)(const struct btf *btf, const struct btf_type *t,
412 u32 type_id, void *data, u8 bits_offsets,
413 struct btf_show *show);
416 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS];
417 static struct btf_type btf_void;
419 static int btf_resolve(struct btf_verifier_env *env,
420 const struct btf_type *t, u32 type_id);
422 static int btf_func_check(struct btf_verifier_env *env,
423 const struct btf_type *t);
425 static bool btf_type_is_modifier(const struct btf_type *t)
427 /* Some of them is not strictly a C modifier
428 * but they are grouped into the same bucket
430 * A type (t) that refers to another
431 * type through t->type AND its size cannot
432 * be determined without following the t->type.
434 * ptr does not fall into this bucket
435 * because its size is always sizeof(void *).
437 switch (BTF_INFO_KIND(t->info)) {
438 case BTF_KIND_TYPEDEF:
439 case BTF_KIND_VOLATILE:
441 case BTF_KIND_RESTRICT:
442 case BTF_KIND_TYPE_TAG:
449 bool btf_type_is_void(const struct btf_type *t)
451 return t == &btf_void;
454 static bool btf_type_is_fwd(const struct btf_type *t)
456 return BTF_INFO_KIND(t->info) == BTF_KIND_FWD;
459 static bool btf_type_nosize(const struct btf_type *t)
461 return btf_type_is_void(t) || btf_type_is_fwd(t) ||
462 btf_type_is_func(t) || btf_type_is_func_proto(t);
465 static bool btf_type_nosize_or_null(const struct btf_type *t)
467 return !t || btf_type_nosize(t);
470 static bool __btf_type_is_struct(const struct btf_type *t)
472 return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
475 static bool btf_type_is_array(const struct btf_type *t)
477 return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
480 static bool btf_type_is_datasec(const struct btf_type *t)
482 return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC;
485 static bool btf_type_is_decl_tag(const struct btf_type *t)
487 return BTF_INFO_KIND(t->info) == BTF_KIND_DECL_TAG;
490 static bool btf_type_is_decl_tag_target(const struct btf_type *t)
492 return btf_type_is_func(t) || btf_type_is_struct(t) ||
493 btf_type_is_var(t) || btf_type_is_typedef(t);
496 u32 btf_nr_types(const struct btf *btf)
501 total += btf->nr_types;
508 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind)
510 const struct btf_type *t;
514 total = btf_nr_types(btf);
515 for (i = 1; i < total; i++) {
516 t = btf_type_by_id(btf, i);
517 if (BTF_INFO_KIND(t->info) != kind)
520 tname = btf_name_by_offset(btf, t->name_off);
521 if (!strcmp(tname, name))
528 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
531 const struct btf_type *t = btf_type_by_id(btf, id);
533 while (btf_type_is_modifier(t)) {
535 t = btf_type_by_id(btf, t->type);
544 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
547 const struct btf_type *t;
549 t = btf_type_skip_modifiers(btf, id, NULL);
550 if (!btf_type_is_ptr(t))
553 return btf_type_skip_modifiers(btf, t->type, res_id);
556 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
559 const struct btf_type *ptype;
561 ptype = btf_type_resolve_ptr(btf, id, res_id);
562 if (ptype && btf_type_is_func_proto(ptype))
568 /* Types that act only as a source, not sink or intermediate
569 * type when resolving.
571 static bool btf_type_is_resolve_source_only(const struct btf_type *t)
573 return btf_type_is_var(t) ||
574 btf_type_is_decl_tag(t) ||
575 btf_type_is_datasec(t);
578 /* What types need to be resolved?
580 * btf_type_is_modifier() is an obvious one.
582 * btf_type_is_struct() because its member refers to
583 * another type (through member->type).
585 * btf_type_is_var() because the variable refers to
586 * another type. btf_type_is_datasec() holds multiple
587 * btf_type_is_var() types that need resolving.
589 * btf_type_is_array() because its element (array->type)
590 * refers to another type. Array can be thought of a
591 * special case of struct while array just has the same
592 * member-type repeated by array->nelems of times.
594 static bool btf_type_needs_resolve(const struct btf_type *t)
596 return btf_type_is_modifier(t) ||
597 btf_type_is_ptr(t) ||
598 btf_type_is_struct(t) ||
599 btf_type_is_array(t) ||
600 btf_type_is_var(t) ||
601 btf_type_is_func(t) ||
602 btf_type_is_decl_tag(t) ||
603 btf_type_is_datasec(t);
606 /* t->size can be used */
607 static bool btf_type_has_size(const struct btf_type *t)
609 switch (BTF_INFO_KIND(t->info)) {
611 case BTF_KIND_STRUCT:
614 case BTF_KIND_DATASEC:
622 static const char *btf_int_encoding_str(u8 encoding)
626 else if (encoding == BTF_INT_SIGNED)
628 else if (encoding == BTF_INT_CHAR)
630 else if (encoding == BTF_INT_BOOL)
636 static u32 btf_type_int(const struct btf_type *t)
638 return *(u32 *)(t + 1);
641 static const struct btf_array *btf_type_array(const struct btf_type *t)
643 return (const struct btf_array *)(t + 1);
646 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
648 return (const struct btf_enum *)(t + 1);
651 static const struct btf_var *btf_type_var(const struct btf_type *t)
653 return (const struct btf_var *)(t + 1);
656 static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
658 return (const struct btf_decl_tag *)(t + 1);
661 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
663 return kind_ops[BTF_INFO_KIND(t->info)];
666 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
668 if (!BTF_STR_OFFSET_VALID(offset))
671 while (offset < btf->start_str_off)
674 offset -= btf->start_str_off;
675 return offset < btf->hdr.str_len;
678 static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
680 if ((first ? !isalpha(c) :
683 ((c == '.' && !dot_ok) ||
689 static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
691 while (offset < btf->start_str_off)
694 offset -= btf->start_str_off;
695 if (offset < btf->hdr.str_len)
696 return &btf->strings[offset];
701 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
703 /* offset must be valid */
704 const char *src = btf_str_by_offset(btf, offset);
705 const char *src_limit;
707 if (!__btf_name_char_ok(*src, true, dot_ok))
710 /* set a limit on identifier length */
711 src_limit = src + KSYM_NAME_LEN;
713 while (*src && src < src_limit) {
714 if (!__btf_name_char_ok(*src, false, dot_ok))
722 /* Only C-style identifier is permitted. This can be relaxed if
725 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
727 return __btf_name_valid(btf, offset, false);
730 static bool btf_name_valid_section(const struct btf *btf, u32 offset)
732 return __btf_name_valid(btf, offset, true);
735 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
742 name = btf_str_by_offset(btf, offset);
743 return name ?: "(invalid-name-offset)";
746 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
748 return btf_str_by_offset(btf, offset);
751 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
753 while (type_id < btf->start_id)
756 type_id -= btf->start_id;
757 if (type_id >= btf->nr_types)
759 return btf->types[type_id];
763 * Regular int is not a bit field and it must be either
764 * u8/u16/u32/u64 or __int128.
766 static bool btf_type_int_is_regular(const struct btf_type *t)
768 u8 nr_bits, nr_bytes;
771 int_data = btf_type_int(t);
772 nr_bits = BTF_INT_BITS(int_data);
773 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
774 if (BITS_PER_BYTE_MASKED(nr_bits) ||
775 BTF_INT_OFFSET(int_data) ||
776 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
777 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
778 nr_bytes != (2 * sizeof(u64)))) {
786 * Check that given struct member is a regular int with expected
789 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
790 const struct btf_member *m,
791 u32 expected_offset, u32 expected_size)
793 const struct btf_type *t;
798 t = btf_type_id_size(btf, &id, NULL);
799 if (!t || !btf_type_is_int(t))
802 int_data = btf_type_int(t);
803 nr_bits = BTF_INT_BITS(int_data);
804 if (btf_type_kflag(s)) {
805 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
806 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
808 /* if kflag set, int should be a regular int and
809 * bit offset should be at byte boundary.
811 return !bitfield_size &&
812 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
813 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
816 if (BTF_INT_OFFSET(int_data) ||
817 BITS_PER_BYTE_MASKED(m->offset) ||
818 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
819 BITS_PER_BYTE_MASKED(nr_bits) ||
820 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
826 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
827 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
830 const struct btf_type *t = btf_type_by_id(btf, id);
832 while (btf_type_is_modifier(t) &&
833 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
834 t = btf_type_by_id(btf, t->type);
840 #define BTF_SHOW_MAX_ITER 10
842 #define BTF_KIND_BIT(kind) (1ULL << kind)
845 * Populate show->state.name with type name information.
846 * Format of type name is
848 * [.member_name = ] (type_name)
850 static const char *btf_show_name(struct btf_show *show)
852 /* BTF_MAX_ITER array suffixes "[]" */
853 const char *array_suffixes = "[][][][][][][][][][]";
854 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
855 /* BTF_MAX_ITER pointer suffixes "*" */
856 const char *ptr_suffixes = "**********";
857 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
858 const char *name = NULL, *prefix = "", *parens = "";
859 const struct btf_member *m = show->state.member;
860 const struct btf_type *t;
861 const struct btf_array *array;
862 u32 id = show->state.type_id;
863 const char *member = NULL;
864 bool show_member = false;
868 show->state.name[0] = '\0';
871 * Don't show type name if we're showing an array member;
872 * in that case we show the array type so don't need to repeat
873 * ourselves for each member.
875 if (show->state.array_member)
878 /* Retrieve member name, if any. */
880 member = btf_name_by_offset(show->btf, m->name_off);
881 show_member = strlen(member) > 0;
886 * Start with type_id, as we have resolved the struct btf_type *
887 * via btf_modifier_show() past the parent typedef to the child
888 * struct, int etc it is defined as. In such cases, the type_id
889 * still represents the starting type while the struct btf_type *
890 * in our show->state points at the resolved type of the typedef.
892 t = btf_type_by_id(show->btf, id);
897 * The goal here is to build up the right number of pointer and
898 * array suffixes while ensuring the type name for a typedef
899 * is represented. Along the way we accumulate a list of
900 * BTF kinds we have encountered, since these will inform later
901 * display; for example, pointer types will not require an
902 * opening "{" for struct, we will just display the pointer value.
904 * We also want to accumulate the right number of pointer or array
905 * indices in the format string while iterating until we get to
906 * the typedef/pointee/array member target type.
908 * We start by pointing at the end of pointer and array suffix
909 * strings; as we accumulate pointers and arrays we move the pointer
910 * or array string backwards so it will show the expected number of
911 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
912 * and/or arrays and typedefs are supported as a precaution.
914 * We also want to get typedef name while proceeding to resolve
915 * type it points to so that we can add parentheses if it is a
916 * "typedef struct" etc.
918 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
920 switch (BTF_INFO_KIND(t->info)) {
921 case BTF_KIND_TYPEDEF:
923 name = btf_name_by_offset(show->btf,
925 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
929 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
933 array = btf_type_array(t);
934 if (array_suffix > array_suffixes)
939 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
940 if (ptr_suffix > ptr_suffixes)
950 t = btf_type_skip_qualifiers(show->btf, id);
952 /* We may not be able to represent this type; bail to be safe */
953 if (i == BTF_SHOW_MAX_ITER)
957 name = btf_name_by_offset(show->btf, t->name_off);
959 switch (BTF_INFO_KIND(t->info)) {
960 case BTF_KIND_STRUCT:
962 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
964 /* if it's an array of struct/union, parens is already set */
965 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
975 /* pointer does not require parens */
976 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
978 /* typedef does not require struct/union/enum prefix */
979 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
985 /* Even if we don't want type name info, we want parentheses etc */
986 if (show->flags & BTF_SHOW_NONAME)
987 snprintf(show->state.name, sizeof(show->state.name), "%s",
990 snprintf(show->state.name, sizeof(show->state.name),
991 "%s%s%s(%s%s%s%s%s%s)%s",
992 /* first 3 strings comprise ".member = " */
993 show_member ? "." : "",
994 show_member ? member : "",
995 show_member ? " = " : "",
996 /* ...next is our prefix (struct, enum, etc) */
998 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
999 /* ...this is the type name itself */
1001 /* ...suffixed by the appropriate '*', '[]' suffixes */
1002 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1003 array_suffix, parens);
1005 return show->state.name;
1008 static const char *__btf_show_indent(struct btf_show *show)
1010 const char *indents = " ";
1011 const char *indent = &indents[strlen(indents)];
1013 if ((indent - show->state.depth) >= indents)
1014 return indent - show->state.depth;
1018 static const char *btf_show_indent(struct btf_show *show)
1020 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1023 static const char *btf_show_newline(struct btf_show *show)
1025 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1028 static const char *btf_show_delim(struct btf_show *show)
1030 if (show->state.depth == 0)
1033 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1034 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1040 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1044 if (!show->state.depth_check) {
1045 va_start(args, fmt);
1046 show->showfn(show, fmt, args);
1051 /* Macros are used here as btf_show_type_value[s]() prepends and appends
1052 * format specifiers to the format specifier passed in; these do the work of
1053 * adding indentation, delimiters etc while the caller simply has to specify
1054 * the type value(s) in the format specifier + value(s).
1056 #define btf_show_type_value(show, fmt, value) \
1058 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \
1059 show->state.depth == 0) { \
1060 btf_show(show, "%s%s" fmt "%s%s", \
1061 btf_show_indent(show), \
1062 btf_show_name(show), \
1063 value, btf_show_delim(show), \
1064 btf_show_newline(show)); \
1065 if (show->state.depth > show->state.depth_to_show) \
1066 show->state.depth_to_show = show->state.depth; \
1070 #define btf_show_type_values(show, fmt, ...) \
1072 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1073 btf_show_name(show), \
1074 __VA_ARGS__, btf_show_delim(show), \
1075 btf_show_newline(show)); \
1076 if (show->state.depth > show->state.depth_to_show) \
1077 show->state.depth_to_show = show->state.depth; \
1080 /* How much is left to copy to safe buffer after @data? */
1081 static int btf_show_obj_size_left(struct btf_show *show, void *data)
1083 return show->obj.head + show->obj.size - data;
1086 /* Is object pointed to by @data of @size already copied to our safe buffer? */
1087 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1089 return data >= show->obj.data &&
1090 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1094 * If object pointed to by @data of @size falls within our safe buffer, return
1095 * the equivalent pointer to the same safe data. Assumes
1096 * copy_from_kernel_nofault() has already happened and our safe buffer is
1099 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1101 if (btf_show_obj_is_safe(show, data, size))
1102 return show->obj.safe + (data - show->obj.data);
1107 * Return a safe-to-access version of data pointed to by @data.
1108 * We do this by copying the relevant amount of information
1109 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1111 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1112 * safe copy is needed.
1114 * Otherwise we need to determine if we have the required amount
1115 * of data (determined by the @data pointer and the size of the
1116 * largest base type we can encounter (represented by
1117 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1118 * that we will be able to print some of the current object,
1119 * and if more is needed a copy will be triggered.
1120 * Some objects such as structs will not fit into the buffer;
1121 * in such cases additional copies when we iterate over their
1122 * members may be needed.
1124 * btf_show_obj_safe() is used to return a safe buffer for
1125 * btf_show_start_type(); this ensures that as we recurse into
1126 * nested types we always have safe data for the given type.
1127 * This approach is somewhat wasteful; it's possible for example
1128 * that when iterating over a large union we'll end up copying the
1129 * same data repeatedly, but the goal is safety not performance.
1130 * We use stack data as opposed to per-CPU buffers because the
1131 * iteration over a type can take some time, and preemption handling
1132 * would greatly complicate use of the safe buffer.
1134 static void *btf_show_obj_safe(struct btf_show *show,
1135 const struct btf_type *t,
1138 const struct btf_type *rt;
1139 int size_left, size;
1142 if (show->flags & BTF_SHOW_UNSAFE)
1145 rt = btf_resolve_size(show->btf, t, &size);
1147 show->state.status = PTR_ERR(rt);
1152 * Is this toplevel object? If so, set total object size and
1153 * initialize pointers. Otherwise check if we still fall within
1154 * our safe object data.
1156 if (show->state.depth == 0) {
1157 show->obj.size = size;
1158 show->obj.head = data;
1161 * If the size of the current object is > our remaining
1162 * safe buffer we _may_ need to do a new copy. However
1163 * consider the case of a nested struct; it's size pushes
1164 * us over the safe buffer limit, but showing any individual
1165 * struct members does not. In such cases, we don't need
1166 * to initiate a fresh copy yet; however we definitely need
1167 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1168 * in our buffer, regardless of the current object size.
1169 * The logic here is that as we resolve types we will
1170 * hit a base type at some point, and we need to be sure
1171 * the next chunk of data is safely available to display
1172 * that type info safely. We cannot rely on the size of
1173 * the current object here because it may be much larger
1174 * than our current buffer (e.g. task_struct is 8k).
1175 * All we want to do here is ensure that we can print the
1176 * next basic type, which we can if either
1177 * - the current type size is within the safe buffer; or
1178 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1181 safe = __btf_show_obj_safe(show, data,
1183 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1187 * We need a new copy to our safe object, either because we haven't
1188 * yet copied and are initializing safe data, or because the data
1189 * we want falls outside the boundaries of the safe object.
1192 size_left = btf_show_obj_size_left(show, data);
1193 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1194 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1195 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1197 if (!show->state.status) {
1198 show->obj.data = data;
1199 safe = show->obj.safe;
1207 * Set the type we are starting to show and return a safe data pointer
1208 * to be used for showing the associated data.
1210 static void *btf_show_start_type(struct btf_show *show,
1211 const struct btf_type *t,
1212 u32 type_id, void *data)
1214 show->state.type = t;
1215 show->state.type_id = type_id;
1216 show->state.name[0] = '\0';
1218 return btf_show_obj_safe(show, t, data);
1221 static void btf_show_end_type(struct btf_show *show)
1223 show->state.type = NULL;
1224 show->state.type_id = 0;
1225 show->state.name[0] = '\0';
1228 static void *btf_show_start_aggr_type(struct btf_show *show,
1229 const struct btf_type *t,
1230 u32 type_id, void *data)
1232 void *safe_data = btf_show_start_type(show, t, type_id, data);
1237 btf_show(show, "%s%s%s", btf_show_indent(show),
1238 btf_show_name(show),
1239 btf_show_newline(show));
1240 show->state.depth++;
1244 static void btf_show_end_aggr_type(struct btf_show *show,
1247 show->state.depth--;
1248 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1249 btf_show_delim(show), btf_show_newline(show));
1250 btf_show_end_type(show);
1253 static void btf_show_start_member(struct btf_show *show,
1254 const struct btf_member *m)
1256 show->state.member = m;
1259 static void btf_show_start_array_member(struct btf_show *show)
1261 show->state.array_member = 1;
1262 btf_show_start_member(show, NULL);
1265 static void btf_show_end_member(struct btf_show *show)
1267 show->state.member = NULL;
1270 static void btf_show_end_array_member(struct btf_show *show)
1272 show->state.array_member = 0;
1273 btf_show_end_member(show);
1276 static void *btf_show_start_array_type(struct btf_show *show,
1277 const struct btf_type *t,
1282 show->state.array_encoding = array_encoding;
1283 show->state.array_terminated = 0;
1284 return btf_show_start_aggr_type(show, t, type_id, data);
1287 static void btf_show_end_array_type(struct btf_show *show)
1289 show->state.array_encoding = 0;
1290 show->state.array_terminated = 0;
1291 btf_show_end_aggr_type(show, "]");
1294 static void *btf_show_start_struct_type(struct btf_show *show,
1295 const struct btf_type *t,
1299 return btf_show_start_aggr_type(show, t, type_id, data);
1302 static void btf_show_end_struct_type(struct btf_show *show)
1304 btf_show_end_aggr_type(show, "}");
1307 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1308 const char *fmt, ...)
1312 va_start(args, fmt);
1313 bpf_verifier_vlog(log, fmt, args);
1317 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1318 const char *fmt, ...)
1320 struct bpf_verifier_log *log = &env->log;
1323 if (!bpf_verifier_log_needed(log))
1326 va_start(args, fmt);
1327 bpf_verifier_vlog(log, fmt, args);
1331 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1332 const struct btf_type *t,
1334 const char *fmt, ...)
1336 struct bpf_verifier_log *log = &env->log;
1337 u8 kind = BTF_INFO_KIND(t->info);
1338 struct btf *btf = env->btf;
1341 if (!bpf_verifier_log_needed(log))
1344 /* btf verifier prints all types it is processing via
1345 * btf_verifier_log_type(..., fmt = NULL).
1346 * Skip those prints for in-kernel BTF verification.
1348 if (log->level == BPF_LOG_KERNEL && !fmt)
1351 __btf_verifier_log(log, "[%u] %s %s%s",
1354 __btf_name_by_offset(btf, t->name_off),
1355 log_details ? " " : "");
1358 btf_type_ops(t)->log_details(env, t);
1361 __btf_verifier_log(log, " ");
1362 va_start(args, fmt);
1363 bpf_verifier_vlog(log, fmt, args);
1367 __btf_verifier_log(log, "\n");
1370 #define btf_verifier_log_type(env, t, ...) \
1371 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1372 #define btf_verifier_log_basic(env, t, ...) \
1373 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1376 static void btf_verifier_log_member(struct btf_verifier_env *env,
1377 const struct btf_type *struct_type,
1378 const struct btf_member *member,
1379 const char *fmt, ...)
1381 struct bpf_verifier_log *log = &env->log;
1382 struct btf *btf = env->btf;
1385 if (!bpf_verifier_log_needed(log))
1388 if (log->level == BPF_LOG_KERNEL && !fmt)
1390 /* The CHECK_META phase already did a btf dump.
1392 * If member is logged again, it must hit an error in
1393 * parsing this member. It is useful to print out which
1394 * struct this member belongs to.
1396 if (env->phase != CHECK_META)
1397 btf_verifier_log_type(env, struct_type, NULL);
1399 if (btf_type_kflag(struct_type))
1400 __btf_verifier_log(log,
1401 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1402 __btf_name_by_offset(btf, member->name_off),
1404 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1405 BTF_MEMBER_BIT_OFFSET(member->offset));
1407 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1408 __btf_name_by_offset(btf, member->name_off),
1409 member->type, member->offset);
1412 __btf_verifier_log(log, " ");
1413 va_start(args, fmt);
1414 bpf_verifier_vlog(log, fmt, args);
1418 __btf_verifier_log(log, "\n");
1422 static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1423 const struct btf_type *datasec_type,
1424 const struct btf_var_secinfo *vsi,
1425 const char *fmt, ...)
1427 struct bpf_verifier_log *log = &env->log;
1430 if (!bpf_verifier_log_needed(log))
1432 if (log->level == BPF_LOG_KERNEL && !fmt)
1434 if (env->phase != CHECK_META)
1435 btf_verifier_log_type(env, datasec_type, NULL);
1437 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1438 vsi->type, vsi->offset, vsi->size);
1440 __btf_verifier_log(log, " ");
1441 va_start(args, fmt);
1442 bpf_verifier_vlog(log, fmt, args);
1446 __btf_verifier_log(log, "\n");
1449 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1452 struct bpf_verifier_log *log = &env->log;
1453 const struct btf *btf = env->btf;
1454 const struct btf_header *hdr;
1456 if (!bpf_verifier_log_needed(log))
1459 if (log->level == BPF_LOG_KERNEL)
1462 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1463 __btf_verifier_log(log, "version: %u\n", hdr->version);
1464 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1465 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1466 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1467 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1468 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1469 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1470 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1473 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1475 struct btf *btf = env->btf;
1477 if (btf->types_size == btf->nr_types) {
1478 /* Expand 'types' array */
1480 struct btf_type **new_types;
1481 u32 expand_by, new_size;
1483 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1484 btf_verifier_log(env, "Exceeded max num of types");
1488 expand_by = max_t(u32, btf->types_size >> 2, 16);
1489 new_size = min_t(u32, BTF_MAX_TYPE,
1490 btf->types_size + expand_by);
1492 new_types = kvcalloc(new_size, sizeof(*new_types),
1493 GFP_KERNEL | __GFP_NOWARN);
1497 if (btf->nr_types == 0) {
1498 if (!btf->base_btf) {
1499 /* lazily init VOID type */
1500 new_types[0] = &btf_void;
1504 memcpy(new_types, btf->types,
1505 sizeof(*btf->types) * btf->nr_types);
1509 btf->types = new_types;
1510 btf->types_size = new_size;
1513 btf->types[btf->nr_types++] = t;
1518 static int btf_alloc_id(struct btf *btf)
1522 idr_preload(GFP_KERNEL);
1523 spin_lock_bh(&btf_idr_lock);
1524 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1527 spin_unlock_bh(&btf_idr_lock);
1530 if (WARN_ON_ONCE(!id))
1533 return id > 0 ? 0 : id;
1536 static void btf_free_id(struct btf *btf)
1538 unsigned long flags;
1541 * In map-in-map, calling map_delete_elem() on outer
1542 * map will call bpf_map_put on the inner map.
1543 * It will then eventually call btf_free_id()
1544 * on the inner map. Some of the map_delete_elem()
1545 * implementation may have irq disabled, so
1546 * we need to use the _irqsave() version instead
1547 * of the _bh() version.
1549 spin_lock_irqsave(&btf_idr_lock, flags);
1550 idr_remove(&btf_idr, btf->id);
1551 spin_unlock_irqrestore(&btf_idr_lock, flags);
1554 static void btf_free_kfunc_set_tab(struct btf *btf)
1556 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1561 /* For module BTF, we directly assign the sets being registered, so
1562 * there is nothing to free except kfunc_set_tab.
1564 if (btf_is_module(btf))
1566 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++) {
1567 for (type = 0; type < ARRAY_SIZE(tab->sets[0]); type++)
1568 kfree(tab->sets[hook][type]);
1572 btf->kfunc_set_tab = NULL;
1575 static void btf_free(struct btf *btf)
1577 btf_free_kfunc_set_tab(btf);
1579 kvfree(btf->resolved_sizes);
1580 kvfree(btf->resolved_ids);
1585 static void btf_free_rcu(struct rcu_head *rcu)
1587 struct btf *btf = container_of(rcu, struct btf, rcu);
1592 void btf_get(struct btf *btf)
1594 refcount_inc(&btf->refcnt);
1597 void btf_put(struct btf *btf)
1599 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1601 call_rcu(&btf->rcu, btf_free_rcu);
1605 static int env_resolve_init(struct btf_verifier_env *env)
1607 struct btf *btf = env->btf;
1608 u32 nr_types = btf->nr_types;
1609 u32 *resolved_sizes = NULL;
1610 u32 *resolved_ids = NULL;
1611 u8 *visit_states = NULL;
1613 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1614 GFP_KERNEL | __GFP_NOWARN);
1615 if (!resolved_sizes)
1618 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1619 GFP_KERNEL | __GFP_NOWARN);
1623 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1624 GFP_KERNEL | __GFP_NOWARN);
1628 btf->resolved_sizes = resolved_sizes;
1629 btf->resolved_ids = resolved_ids;
1630 env->visit_states = visit_states;
1635 kvfree(resolved_sizes);
1636 kvfree(resolved_ids);
1637 kvfree(visit_states);
1641 static void btf_verifier_env_free(struct btf_verifier_env *env)
1643 kvfree(env->visit_states);
1647 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1648 const struct btf_type *next_type)
1650 switch (env->resolve_mode) {
1652 /* int, enum or void is a sink */
1653 return !btf_type_needs_resolve(next_type);
1655 /* int, enum, void, struct, array, func or func_proto is a sink
1658 return !btf_type_is_modifier(next_type) &&
1659 !btf_type_is_ptr(next_type);
1660 case RESOLVE_STRUCT_OR_ARRAY:
1661 /* int, enum, void, ptr, func or func_proto is a sink
1662 * for struct and array
1664 return !btf_type_is_modifier(next_type) &&
1665 !btf_type_is_array(next_type) &&
1666 !btf_type_is_struct(next_type);
1672 static bool env_type_is_resolved(const struct btf_verifier_env *env,
1675 /* base BTF types should be resolved by now */
1676 if (type_id < env->btf->start_id)
1679 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1682 static int env_stack_push(struct btf_verifier_env *env,
1683 const struct btf_type *t, u32 type_id)
1685 const struct btf *btf = env->btf;
1686 struct resolve_vertex *v;
1688 if (env->top_stack == MAX_RESOLVE_DEPTH)
1691 if (type_id < btf->start_id
1692 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1695 env->visit_states[type_id - btf->start_id] = VISITED;
1697 v = &env->stack[env->top_stack++];
1699 v->type_id = type_id;
1702 if (env->resolve_mode == RESOLVE_TBD) {
1703 if (btf_type_is_ptr(t))
1704 env->resolve_mode = RESOLVE_PTR;
1705 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1706 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1712 static void env_stack_set_next_member(struct btf_verifier_env *env,
1715 env->stack[env->top_stack - 1].next_member = next_member;
1718 static void env_stack_pop_resolved(struct btf_verifier_env *env,
1719 u32 resolved_type_id,
1722 u32 type_id = env->stack[--(env->top_stack)].type_id;
1723 struct btf *btf = env->btf;
1725 type_id -= btf->start_id; /* adjust to local type id */
1726 btf->resolved_sizes[type_id] = resolved_size;
1727 btf->resolved_ids[type_id] = resolved_type_id;
1728 env->visit_states[type_id] = RESOLVED;
1731 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1733 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1736 /* Resolve the size of a passed-in "type"
1738 * type: is an array (e.g. u32 array[x][y])
1739 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1740 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1741 * corresponds to the return type.
1743 * *elem_id: id of u32
1744 * *total_nelems: (x * y). Hence, individual elem size is
1745 * (*type_size / *total_nelems)
1746 * *type_id: id of type if it's changed within the function, 0 if not
1748 * type: is not an array (e.g. const struct X)
1749 * return type: type "struct X"
1750 * *type_size: sizeof(struct X)
1751 * *elem_type: same as return type ("struct X")
1754 * *type_id: id of type if it's changed within the function, 0 if not
1756 static const struct btf_type *
1757 __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1758 u32 *type_size, const struct btf_type **elem_type,
1759 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1761 const struct btf_type *array_type = NULL;
1762 const struct btf_array *array = NULL;
1763 u32 i, size, nelems = 1, id = 0;
1765 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1766 switch (BTF_INFO_KIND(type->info)) {
1767 /* type->size can be used */
1769 case BTF_KIND_STRUCT:
1770 case BTF_KIND_UNION:
1772 case BTF_KIND_FLOAT:
1777 size = sizeof(void *);
1781 case BTF_KIND_TYPEDEF:
1782 case BTF_KIND_VOLATILE:
1783 case BTF_KIND_CONST:
1784 case BTF_KIND_RESTRICT:
1785 case BTF_KIND_TYPE_TAG:
1787 type = btf_type_by_id(btf, type->type);
1790 case BTF_KIND_ARRAY:
1793 array = btf_type_array(type);
1794 if (nelems && array->nelems > U32_MAX / nelems)
1795 return ERR_PTR(-EINVAL);
1796 nelems *= array->nelems;
1797 type = btf_type_by_id(btf, array->type);
1800 /* type without size */
1802 return ERR_PTR(-EINVAL);
1806 return ERR_PTR(-EINVAL);
1809 if (nelems && size > U32_MAX / nelems)
1810 return ERR_PTR(-EINVAL);
1812 *type_size = nelems * size;
1814 *total_nelems = nelems;
1818 *elem_id = array ? array->type : 0;
1822 return array_type ? : type;
1825 const struct btf_type *
1826 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1829 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1832 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1834 while (type_id < btf->start_id)
1835 btf = btf->base_btf;
1837 return btf->resolved_ids[type_id - btf->start_id];
1840 /* The input param "type_id" must point to a needs_resolve type */
1841 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1844 *type_id = btf_resolved_type_id(btf, *type_id);
1845 return btf_type_by_id(btf, *type_id);
1848 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1850 while (type_id < btf->start_id)
1851 btf = btf->base_btf;
1853 return btf->resolved_sizes[type_id - btf->start_id];
1856 const struct btf_type *btf_type_id_size(const struct btf *btf,
1857 u32 *type_id, u32 *ret_size)
1859 const struct btf_type *size_type;
1860 u32 size_type_id = *type_id;
1863 size_type = btf_type_by_id(btf, size_type_id);
1864 if (btf_type_nosize_or_null(size_type))
1867 if (btf_type_has_size(size_type)) {
1868 size = size_type->size;
1869 } else if (btf_type_is_array(size_type)) {
1870 size = btf_resolved_type_size(btf, size_type_id);
1871 } else if (btf_type_is_ptr(size_type)) {
1872 size = sizeof(void *);
1874 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1875 !btf_type_is_var(size_type)))
1878 size_type_id = btf_resolved_type_id(btf, size_type_id);
1879 size_type = btf_type_by_id(btf, size_type_id);
1880 if (btf_type_nosize_or_null(size_type))
1882 else if (btf_type_has_size(size_type))
1883 size = size_type->size;
1884 else if (btf_type_is_array(size_type))
1885 size = btf_resolved_type_size(btf, size_type_id);
1886 else if (btf_type_is_ptr(size_type))
1887 size = sizeof(void *);
1892 *type_id = size_type_id;
1899 static int btf_df_check_member(struct btf_verifier_env *env,
1900 const struct btf_type *struct_type,
1901 const struct btf_member *member,
1902 const struct btf_type *member_type)
1904 btf_verifier_log_basic(env, struct_type,
1905 "Unsupported check_member");
1909 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1910 const struct btf_type *struct_type,
1911 const struct btf_member *member,
1912 const struct btf_type *member_type)
1914 btf_verifier_log_basic(env, struct_type,
1915 "Unsupported check_kflag_member");
1919 /* Used for ptr, array struct/union and float type members.
1920 * int, enum and modifier types have their specific callback functions.
1922 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1923 const struct btf_type *struct_type,
1924 const struct btf_member *member,
1925 const struct btf_type *member_type)
1927 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1928 btf_verifier_log_member(env, struct_type, member,
1929 "Invalid member bitfield_size");
1933 /* bitfield size is 0, so member->offset represents bit offset only.
1934 * It is safe to call non kflag check_member variants.
1936 return btf_type_ops(member_type)->check_member(env, struct_type,
1941 static int btf_df_resolve(struct btf_verifier_env *env,
1942 const struct resolve_vertex *v)
1944 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1948 static void btf_df_show(const struct btf *btf, const struct btf_type *t,
1949 u32 type_id, void *data, u8 bits_offsets,
1950 struct btf_show *show)
1952 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1955 static int btf_int_check_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 int_data = btf_type_int(member_type);
1961 u32 struct_bits_off = member->offset;
1962 u32 struct_size = struct_type->size;
1966 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
1967 btf_verifier_log_member(env, struct_type, member,
1968 "bits_offset exceeds U32_MAX");
1972 struct_bits_off += BTF_INT_OFFSET(int_data);
1973 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
1974 nr_copy_bits = BTF_INT_BITS(int_data) +
1975 BITS_PER_BYTE_MASKED(struct_bits_off);
1977 if (nr_copy_bits > BITS_PER_U128) {
1978 btf_verifier_log_member(env, struct_type, member,
1979 "nr_copy_bits exceeds 128");
1983 if (struct_size < bytes_offset ||
1984 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
1985 btf_verifier_log_member(env, struct_type, member,
1986 "Member exceeds struct_size");
1993 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
1994 const struct btf_type *struct_type,
1995 const struct btf_member *member,
1996 const struct btf_type *member_type)
1998 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
1999 u32 int_data = btf_type_int(member_type);
2000 u32 struct_size = struct_type->size;
2003 /* a regular int type is required for the kflag int member */
2004 if (!btf_type_int_is_regular(member_type)) {
2005 btf_verifier_log_member(env, struct_type, member,
2006 "Invalid member base type");
2010 /* check sanity of bitfield size */
2011 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2012 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2013 nr_int_data_bits = BTF_INT_BITS(int_data);
2015 /* Not a bitfield member, member offset must be at byte
2018 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2019 btf_verifier_log_member(env, struct_type, member,
2020 "Invalid member offset");
2024 nr_bits = nr_int_data_bits;
2025 } else if (nr_bits > nr_int_data_bits) {
2026 btf_verifier_log_member(env, struct_type, member,
2027 "Invalid member bitfield_size");
2031 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2032 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2033 if (nr_copy_bits > BITS_PER_U128) {
2034 btf_verifier_log_member(env, struct_type, member,
2035 "nr_copy_bits exceeds 128");
2039 if (struct_size < bytes_offset ||
2040 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2041 btf_verifier_log_member(env, struct_type, member,
2042 "Member exceeds struct_size");
2049 static s32 btf_int_check_meta(struct btf_verifier_env *env,
2050 const struct btf_type *t,
2053 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2056 if (meta_left < meta_needed) {
2057 btf_verifier_log_basic(env, t,
2058 "meta_left:%u meta_needed:%u",
2059 meta_left, meta_needed);
2063 if (btf_type_vlen(t)) {
2064 btf_verifier_log_type(env, t, "vlen != 0");
2068 if (btf_type_kflag(t)) {
2069 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2073 int_data = btf_type_int(t);
2074 if (int_data & ~BTF_INT_MASK) {
2075 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2080 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2082 if (nr_bits > BITS_PER_U128) {
2083 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2088 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2089 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2094 * Only one of the encoding bits is allowed and it
2095 * should be sufficient for the pretty print purpose (i.e. decoding).
2096 * Multiple bits can be allowed later if it is found
2097 * to be insufficient.
2099 encoding = BTF_INT_ENCODING(int_data);
2101 encoding != BTF_INT_SIGNED &&
2102 encoding != BTF_INT_CHAR &&
2103 encoding != BTF_INT_BOOL) {
2104 btf_verifier_log_type(env, t, "Unsupported encoding");
2108 btf_verifier_log_type(env, t, NULL);
2113 static void btf_int_log(struct btf_verifier_env *env,
2114 const struct btf_type *t)
2116 int int_data = btf_type_int(t);
2118 btf_verifier_log(env,
2119 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2120 t->size, BTF_INT_OFFSET(int_data),
2121 BTF_INT_BITS(int_data),
2122 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2125 static void btf_int128_print(struct btf_show *show, void *data)
2127 /* data points to a __int128 number.
2129 * int128_num = *(__int128 *)data;
2130 * The below formulas shows what upper_num and lower_num represents:
2131 * upper_num = int128_num >> 64;
2132 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2134 u64 upper_num, lower_num;
2136 #ifdef __BIG_ENDIAN_BITFIELD
2137 upper_num = *(u64 *)data;
2138 lower_num = *(u64 *)(data + 8);
2140 upper_num = *(u64 *)(data + 8);
2141 lower_num = *(u64 *)data;
2144 btf_show_type_value(show, "0x%llx", lower_num);
2146 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2150 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2151 u16 right_shift_bits)
2153 u64 upper_num, lower_num;
2155 #ifdef __BIG_ENDIAN_BITFIELD
2156 upper_num = print_num[0];
2157 lower_num = print_num[1];
2159 upper_num = print_num[1];
2160 lower_num = print_num[0];
2163 /* shake out un-needed bits by shift/or operations */
2164 if (left_shift_bits >= 64) {
2165 upper_num = lower_num << (left_shift_bits - 64);
2168 upper_num = (upper_num << left_shift_bits) |
2169 (lower_num >> (64 - left_shift_bits));
2170 lower_num = lower_num << left_shift_bits;
2173 if (right_shift_bits >= 64) {
2174 lower_num = upper_num >> (right_shift_bits - 64);
2177 lower_num = (lower_num >> right_shift_bits) |
2178 (upper_num << (64 - right_shift_bits));
2179 upper_num = upper_num >> right_shift_bits;
2182 #ifdef __BIG_ENDIAN_BITFIELD
2183 print_num[0] = upper_num;
2184 print_num[1] = lower_num;
2186 print_num[0] = lower_num;
2187 print_num[1] = upper_num;
2191 static void btf_bitfield_show(void *data, u8 bits_offset,
2192 u8 nr_bits, struct btf_show *show)
2194 u16 left_shift_bits, right_shift_bits;
2197 u64 print_num[2] = {};
2199 nr_copy_bits = nr_bits + bits_offset;
2200 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2202 memcpy(print_num, data, nr_copy_bytes);
2204 #ifdef __BIG_ENDIAN_BITFIELD
2205 left_shift_bits = bits_offset;
2207 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2209 right_shift_bits = BITS_PER_U128 - nr_bits;
2211 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2212 btf_int128_print(show, print_num);
2216 static void btf_int_bits_show(const struct btf *btf,
2217 const struct btf_type *t,
2218 void *data, u8 bits_offset,
2219 struct btf_show *show)
2221 u32 int_data = btf_type_int(t);
2222 u8 nr_bits = BTF_INT_BITS(int_data);
2223 u8 total_bits_offset;
2226 * bits_offset is at most 7.
2227 * BTF_INT_OFFSET() cannot exceed 128 bits.
2229 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2230 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2231 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2232 btf_bitfield_show(data, bits_offset, nr_bits, show);
2235 static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2236 u32 type_id, void *data, u8 bits_offset,
2237 struct btf_show *show)
2239 u32 int_data = btf_type_int(t);
2240 u8 encoding = BTF_INT_ENCODING(int_data);
2241 bool sign = encoding & BTF_INT_SIGNED;
2242 u8 nr_bits = BTF_INT_BITS(int_data);
2245 safe_data = btf_show_start_type(show, t, type_id, data);
2249 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2250 BITS_PER_BYTE_MASKED(nr_bits)) {
2251 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2257 btf_int128_print(show, safe_data);
2261 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2263 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2267 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2269 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2273 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2275 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2278 if (show->state.array_encoding == BTF_INT_CHAR) {
2279 /* check for null terminator */
2280 if (show->state.array_terminated)
2282 if (*(char *)data == '\0') {
2283 show->state.array_terminated = 1;
2286 if (isprint(*(char *)data)) {
2287 btf_show_type_value(show, "'%c'",
2288 *(char *)safe_data);
2293 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2295 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2298 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2302 btf_show_end_type(show);
2305 static const struct btf_kind_operations int_ops = {
2306 .check_meta = btf_int_check_meta,
2307 .resolve = btf_df_resolve,
2308 .check_member = btf_int_check_member,
2309 .check_kflag_member = btf_int_check_kflag_member,
2310 .log_details = btf_int_log,
2311 .show = btf_int_show,
2314 static int btf_modifier_check_member(struct btf_verifier_env *env,
2315 const struct btf_type *struct_type,
2316 const struct btf_member *member,
2317 const struct btf_type *member_type)
2319 const struct btf_type *resolved_type;
2320 u32 resolved_type_id = member->type;
2321 struct btf_member resolved_member;
2322 struct btf *btf = env->btf;
2324 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2325 if (!resolved_type) {
2326 btf_verifier_log_member(env, struct_type, member,
2331 resolved_member = *member;
2332 resolved_member.type = resolved_type_id;
2334 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2339 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2340 const struct btf_type *struct_type,
2341 const struct btf_member *member,
2342 const struct btf_type *member_type)
2344 const struct btf_type *resolved_type;
2345 u32 resolved_type_id = member->type;
2346 struct btf_member resolved_member;
2347 struct btf *btf = env->btf;
2349 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2350 if (!resolved_type) {
2351 btf_verifier_log_member(env, struct_type, member,
2356 resolved_member = *member;
2357 resolved_member.type = resolved_type_id;
2359 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2364 static int btf_ptr_check_member(struct btf_verifier_env *env,
2365 const struct btf_type *struct_type,
2366 const struct btf_member *member,
2367 const struct btf_type *member_type)
2369 u32 struct_size, struct_bits_off, bytes_offset;
2371 struct_size = struct_type->size;
2372 struct_bits_off = member->offset;
2373 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2375 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2376 btf_verifier_log_member(env, struct_type, member,
2377 "Member is not byte aligned");
2381 if (struct_size - bytes_offset < sizeof(void *)) {
2382 btf_verifier_log_member(env, struct_type, member,
2383 "Member exceeds struct_size");
2390 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2391 const struct btf_type *t,
2396 if (btf_type_vlen(t)) {
2397 btf_verifier_log_type(env, t, "vlen != 0");
2401 if (btf_type_kflag(t)) {
2402 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2406 if (!BTF_TYPE_ID_VALID(t->type)) {
2407 btf_verifier_log_type(env, t, "Invalid type_id");
2411 /* typedef/type_tag type must have a valid name, and other ref types,
2412 * volatile, const, restrict, should have a null name.
2414 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2416 !btf_name_valid_identifier(env->btf, t->name_off)) {
2417 btf_verifier_log_type(env, t, "Invalid name");
2420 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2421 value = btf_name_by_offset(env->btf, t->name_off);
2422 if (!value || !value[0]) {
2423 btf_verifier_log_type(env, t, "Invalid name");
2428 btf_verifier_log_type(env, t, "Invalid name");
2433 btf_verifier_log_type(env, t, NULL);
2438 static int btf_modifier_resolve(struct btf_verifier_env *env,
2439 const struct resolve_vertex *v)
2441 const struct btf_type *t = v->t;
2442 const struct btf_type *next_type;
2443 u32 next_type_id = t->type;
2444 struct btf *btf = env->btf;
2446 next_type = btf_type_by_id(btf, next_type_id);
2447 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2448 btf_verifier_log_type(env, v->t, "Invalid type_id");
2452 if (!env_type_is_resolve_sink(env, next_type) &&
2453 !env_type_is_resolved(env, next_type_id))
2454 return env_stack_push(env, next_type, next_type_id);
2456 /* Figure out the resolved next_type_id with size.
2457 * They will be stored in the current modifier's
2458 * resolved_ids and resolved_sizes such that it can
2459 * save us a few type-following when we use it later (e.g. in
2462 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2463 if (env_type_is_resolved(env, next_type_id))
2464 next_type = btf_type_id_resolve(btf, &next_type_id);
2466 /* "typedef void new_void", "const void"...etc */
2467 if (!btf_type_is_void(next_type) &&
2468 !btf_type_is_fwd(next_type) &&
2469 !btf_type_is_func_proto(next_type)) {
2470 btf_verifier_log_type(env, v->t, "Invalid type_id");
2475 env_stack_pop_resolved(env, next_type_id, 0);
2480 static int btf_var_resolve(struct btf_verifier_env *env,
2481 const struct resolve_vertex *v)
2483 const struct btf_type *next_type;
2484 const struct btf_type *t = v->t;
2485 u32 next_type_id = t->type;
2486 struct btf *btf = env->btf;
2488 next_type = btf_type_by_id(btf, next_type_id);
2489 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2490 btf_verifier_log_type(env, v->t, "Invalid type_id");
2494 if (!env_type_is_resolve_sink(env, next_type) &&
2495 !env_type_is_resolved(env, next_type_id))
2496 return env_stack_push(env, next_type, next_type_id);
2498 if (btf_type_is_modifier(next_type)) {
2499 const struct btf_type *resolved_type;
2500 u32 resolved_type_id;
2502 resolved_type_id = next_type_id;
2503 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2505 if (btf_type_is_ptr(resolved_type) &&
2506 !env_type_is_resolve_sink(env, resolved_type) &&
2507 !env_type_is_resolved(env, resolved_type_id))
2508 return env_stack_push(env, resolved_type,
2512 /* We must resolve to something concrete at this point, no
2513 * forward types or similar that would resolve to size of
2516 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2517 btf_verifier_log_type(env, v->t, "Invalid type_id");
2521 env_stack_pop_resolved(env, next_type_id, 0);
2526 static int btf_ptr_resolve(struct btf_verifier_env *env,
2527 const struct resolve_vertex *v)
2529 const struct btf_type *next_type;
2530 const struct btf_type *t = v->t;
2531 u32 next_type_id = t->type;
2532 struct btf *btf = env->btf;
2534 next_type = btf_type_by_id(btf, next_type_id);
2535 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2536 btf_verifier_log_type(env, v->t, "Invalid type_id");
2540 if (!env_type_is_resolve_sink(env, next_type) &&
2541 !env_type_is_resolved(env, next_type_id))
2542 return env_stack_push(env, next_type, next_type_id);
2544 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2545 * the modifier may have stopped resolving when it was resolved
2546 * to a ptr (last-resolved-ptr).
2548 * We now need to continue from the last-resolved-ptr to
2549 * ensure the last-resolved-ptr will not referring back to
2550 * the currenct ptr (t).
2552 if (btf_type_is_modifier(next_type)) {
2553 const struct btf_type *resolved_type;
2554 u32 resolved_type_id;
2556 resolved_type_id = next_type_id;
2557 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2559 if (btf_type_is_ptr(resolved_type) &&
2560 !env_type_is_resolve_sink(env, resolved_type) &&
2561 !env_type_is_resolved(env, resolved_type_id))
2562 return env_stack_push(env, resolved_type,
2566 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2567 if (env_type_is_resolved(env, next_type_id))
2568 next_type = btf_type_id_resolve(btf, &next_type_id);
2570 if (!btf_type_is_void(next_type) &&
2571 !btf_type_is_fwd(next_type) &&
2572 !btf_type_is_func_proto(next_type)) {
2573 btf_verifier_log_type(env, v->t, "Invalid type_id");
2578 env_stack_pop_resolved(env, next_type_id, 0);
2583 static void btf_modifier_show(const struct btf *btf,
2584 const struct btf_type *t,
2585 u32 type_id, void *data,
2586 u8 bits_offset, struct btf_show *show)
2588 if (btf->resolved_ids)
2589 t = btf_type_id_resolve(btf, &type_id);
2591 t = btf_type_skip_modifiers(btf, type_id, NULL);
2593 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2596 static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2597 u32 type_id, void *data, u8 bits_offset,
2598 struct btf_show *show)
2600 t = btf_type_id_resolve(btf, &type_id);
2602 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2605 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2606 u32 type_id, void *data, u8 bits_offset,
2607 struct btf_show *show)
2611 safe_data = btf_show_start_type(show, t, type_id, data);
2615 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2616 if (show->flags & BTF_SHOW_PTR_RAW)
2617 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2619 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2620 btf_show_end_type(show);
2623 static void btf_ref_type_log(struct btf_verifier_env *env,
2624 const struct btf_type *t)
2626 btf_verifier_log(env, "type_id=%u", t->type);
2629 static struct btf_kind_operations modifier_ops = {
2630 .check_meta = btf_ref_type_check_meta,
2631 .resolve = btf_modifier_resolve,
2632 .check_member = btf_modifier_check_member,
2633 .check_kflag_member = btf_modifier_check_kflag_member,
2634 .log_details = btf_ref_type_log,
2635 .show = btf_modifier_show,
2638 static struct btf_kind_operations ptr_ops = {
2639 .check_meta = btf_ref_type_check_meta,
2640 .resolve = btf_ptr_resolve,
2641 .check_member = btf_ptr_check_member,
2642 .check_kflag_member = btf_generic_check_kflag_member,
2643 .log_details = btf_ref_type_log,
2644 .show = btf_ptr_show,
2647 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2648 const struct btf_type *t,
2651 if (btf_type_vlen(t)) {
2652 btf_verifier_log_type(env, t, "vlen != 0");
2657 btf_verifier_log_type(env, t, "type != 0");
2661 /* fwd type must have a valid name */
2663 !btf_name_valid_identifier(env->btf, t->name_off)) {
2664 btf_verifier_log_type(env, t, "Invalid name");
2668 btf_verifier_log_type(env, t, NULL);
2673 static void btf_fwd_type_log(struct btf_verifier_env *env,
2674 const struct btf_type *t)
2676 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2679 static struct btf_kind_operations fwd_ops = {
2680 .check_meta = btf_fwd_check_meta,
2681 .resolve = btf_df_resolve,
2682 .check_member = btf_df_check_member,
2683 .check_kflag_member = btf_df_check_kflag_member,
2684 .log_details = btf_fwd_type_log,
2685 .show = btf_df_show,
2688 static int btf_array_check_member(struct btf_verifier_env *env,
2689 const struct btf_type *struct_type,
2690 const struct btf_member *member,
2691 const struct btf_type *member_type)
2693 u32 struct_bits_off = member->offset;
2694 u32 struct_size, bytes_offset;
2695 u32 array_type_id, array_size;
2696 struct btf *btf = env->btf;
2698 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2699 btf_verifier_log_member(env, struct_type, member,
2700 "Member is not byte aligned");
2704 array_type_id = member->type;
2705 btf_type_id_size(btf, &array_type_id, &array_size);
2706 struct_size = struct_type->size;
2707 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2708 if (struct_size - bytes_offset < array_size) {
2709 btf_verifier_log_member(env, struct_type, member,
2710 "Member exceeds struct_size");
2717 static s32 btf_array_check_meta(struct btf_verifier_env *env,
2718 const struct btf_type *t,
2721 const struct btf_array *array = btf_type_array(t);
2722 u32 meta_needed = sizeof(*array);
2724 if (meta_left < meta_needed) {
2725 btf_verifier_log_basic(env, t,
2726 "meta_left:%u meta_needed:%u",
2727 meta_left, meta_needed);
2731 /* array type should not have a name */
2733 btf_verifier_log_type(env, t, "Invalid name");
2737 if (btf_type_vlen(t)) {
2738 btf_verifier_log_type(env, t, "vlen != 0");
2742 if (btf_type_kflag(t)) {
2743 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2748 btf_verifier_log_type(env, t, "size != 0");
2752 /* Array elem type and index type cannot be in type void,
2753 * so !array->type and !array->index_type are not allowed.
2755 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2756 btf_verifier_log_type(env, t, "Invalid elem");
2760 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2761 btf_verifier_log_type(env, t, "Invalid index");
2765 btf_verifier_log_type(env, t, NULL);
2770 static int btf_array_resolve(struct btf_verifier_env *env,
2771 const struct resolve_vertex *v)
2773 const struct btf_array *array = btf_type_array(v->t);
2774 const struct btf_type *elem_type, *index_type;
2775 u32 elem_type_id, index_type_id;
2776 struct btf *btf = env->btf;
2779 /* Check array->index_type */
2780 index_type_id = array->index_type;
2781 index_type = btf_type_by_id(btf, index_type_id);
2782 if (btf_type_nosize_or_null(index_type) ||
2783 btf_type_is_resolve_source_only(index_type)) {
2784 btf_verifier_log_type(env, v->t, "Invalid index");
2788 if (!env_type_is_resolve_sink(env, index_type) &&
2789 !env_type_is_resolved(env, index_type_id))
2790 return env_stack_push(env, index_type, index_type_id);
2792 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2793 if (!index_type || !btf_type_is_int(index_type) ||
2794 !btf_type_int_is_regular(index_type)) {
2795 btf_verifier_log_type(env, v->t, "Invalid index");
2799 /* Check array->type */
2800 elem_type_id = array->type;
2801 elem_type = btf_type_by_id(btf, elem_type_id);
2802 if (btf_type_nosize_or_null(elem_type) ||
2803 btf_type_is_resolve_source_only(elem_type)) {
2804 btf_verifier_log_type(env, v->t,
2809 if (!env_type_is_resolve_sink(env, elem_type) &&
2810 !env_type_is_resolved(env, elem_type_id))
2811 return env_stack_push(env, elem_type, elem_type_id);
2813 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2815 btf_verifier_log_type(env, v->t, "Invalid elem");
2819 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2820 btf_verifier_log_type(env, v->t, "Invalid array of int");
2824 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2825 btf_verifier_log_type(env, v->t,
2826 "Array size overflows U32_MAX");
2830 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2835 static void btf_array_log(struct btf_verifier_env *env,
2836 const struct btf_type *t)
2838 const struct btf_array *array = btf_type_array(t);
2840 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2841 array->type, array->index_type, array->nelems);
2844 static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2845 u32 type_id, void *data, u8 bits_offset,
2846 struct btf_show *show)
2848 const struct btf_array *array = btf_type_array(t);
2849 const struct btf_kind_operations *elem_ops;
2850 const struct btf_type *elem_type;
2851 u32 i, elem_size = 0, elem_type_id;
2854 elem_type_id = array->type;
2855 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2856 if (elem_type && btf_type_has_size(elem_type))
2857 elem_size = elem_type->size;
2859 if (elem_type && btf_type_is_int(elem_type)) {
2860 u32 int_type = btf_type_int(elem_type);
2862 encoding = BTF_INT_ENCODING(int_type);
2865 * BTF_INT_CHAR encoding never seems to be set for
2866 * char arrays, so if size is 1 and element is
2867 * printable as a char, we'll do that.
2870 encoding = BTF_INT_CHAR;
2873 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2878 elem_ops = btf_type_ops(elem_type);
2880 for (i = 0; i < array->nelems; i++) {
2882 btf_show_start_array_member(show);
2884 elem_ops->show(btf, elem_type, elem_type_id, data,
2888 btf_show_end_array_member(show);
2890 if (show->state.array_terminated)
2894 btf_show_end_array_type(show);
2897 static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2898 u32 type_id, void *data, u8 bits_offset,
2899 struct btf_show *show)
2901 const struct btf_member *m = show->state.member;
2904 * First check if any members would be shown (are non-zero).
2905 * See comments above "struct btf_show" definition for more
2906 * details on how this works at a high-level.
2908 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2909 if (!show->state.depth_check) {
2910 show->state.depth_check = show->state.depth + 1;
2911 show->state.depth_to_show = 0;
2913 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2914 show->state.member = m;
2916 if (show->state.depth_check != show->state.depth + 1)
2918 show->state.depth_check = 0;
2920 if (show->state.depth_to_show <= show->state.depth)
2923 * Reaching here indicates we have recursed and found
2924 * non-zero array member(s).
2927 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2930 static struct btf_kind_operations array_ops = {
2931 .check_meta = btf_array_check_meta,
2932 .resolve = btf_array_resolve,
2933 .check_member = btf_array_check_member,
2934 .check_kflag_member = btf_generic_check_kflag_member,
2935 .log_details = btf_array_log,
2936 .show = btf_array_show,
2939 static int btf_struct_check_member(struct btf_verifier_env *env,
2940 const struct btf_type *struct_type,
2941 const struct btf_member *member,
2942 const struct btf_type *member_type)
2944 u32 struct_bits_off = member->offset;
2945 u32 struct_size, bytes_offset;
2947 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2948 btf_verifier_log_member(env, struct_type, member,
2949 "Member is not byte aligned");
2953 struct_size = struct_type->size;
2954 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2955 if (struct_size - bytes_offset < member_type->size) {
2956 btf_verifier_log_member(env, struct_type, member,
2957 "Member exceeds struct_size");
2964 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
2965 const struct btf_type *t,
2968 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
2969 const struct btf_member *member;
2970 u32 meta_needed, last_offset;
2971 struct btf *btf = env->btf;
2972 u32 struct_size = t->size;
2976 meta_needed = btf_type_vlen(t) * sizeof(*member);
2977 if (meta_left < meta_needed) {
2978 btf_verifier_log_basic(env, t,
2979 "meta_left:%u meta_needed:%u",
2980 meta_left, meta_needed);
2984 /* struct type either no name or a valid one */
2986 !btf_name_valid_identifier(env->btf, t->name_off)) {
2987 btf_verifier_log_type(env, t, "Invalid name");
2991 btf_verifier_log_type(env, t, NULL);
2994 for_each_member(i, t, member) {
2995 if (!btf_name_offset_valid(btf, member->name_off)) {
2996 btf_verifier_log_member(env, t, member,
2997 "Invalid member name_offset:%u",
3002 /* struct member either no name or a valid one */
3003 if (member->name_off &&
3004 !btf_name_valid_identifier(btf, member->name_off)) {
3005 btf_verifier_log_member(env, t, member, "Invalid name");
3008 /* A member cannot be in type void */
3009 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3010 btf_verifier_log_member(env, t, member,
3015 offset = __btf_member_bit_offset(t, member);
3016 if (is_union && offset) {
3017 btf_verifier_log_member(env, t, member,
3018 "Invalid member bits_offset");
3023 * ">" instead of ">=" because the last member could be
3026 if (last_offset > offset) {
3027 btf_verifier_log_member(env, t, member,
3028 "Invalid member bits_offset");
3032 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3033 btf_verifier_log_member(env, t, member,
3034 "Member bits_offset exceeds its struct size");
3038 btf_verifier_log_member(env, t, member, NULL);
3039 last_offset = offset;
3045 static int btf_struct_resolve(struct btf_verifier_env *env,
3046 const struct resolve_vertex *v)
3048 const struct btf_member *member;
3052 /* Before continue resolving the next_member,
3053 * ensure the last member is indeed resolved to a
3054 * type with size info.
3056 if (v->next_member) {
3057 const struct btf_type *last_member_type;
3058 const struct btf_member *last_member;
3059 u16 last_member_type_id;
3061 last_member = btf_type_member(v->t) + v->next_member - 1;
3062 last_member_type_id = last_member->type;
3063 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3064 last_member_type_id)))
3067 last_member_type = btf_type_by_id(env->btf,
3068 last_member_type_id);
3069 if (btf_type_kflag(v->t))
3070 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3074 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3081 for_each_member_from(i, v->next_member, v->t, member) {
3082 u32 member_type_id = member->type;
3083 const struct btf_type *member_type = btf_type_by_id(env->btf,
3086 if (btf_type_nosize_or_null(member_type) ||
3087 btf_type_is_resolve_source_only(member_type)) {
3088 btf_verifier_log_member(env, v->t, member,
3093 if (!env_type_is_resolve_sink(env, member_type) &&
3094 !env_type_is_resolved(env, member_type_id)) {
3095 env_stack_set_next_member(env, i + 1);
3096 return env_stack_push(env, member_type, member_type_id);
3099 if (btf_type_kflag(v->t))
3100 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3104 err = btf_type_ops(member_type)->check_member(env, v->t,
3111 env_stack_pop_resolved(env, 0, 0);
3116 static void btf_struct_log(struct btf_verifier_env *env,
3117 const struct btf_type *t)
3119 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3122 static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t,
3123 const char *name, int sz, int align)
3125 const struct btf_member *member;
3126 u32 i, off = -ENOENT;
3128 for_each_member(i, t, member) {
3129 const struct btf_type *member_type = btf_type_by_id(btf,
3131 if (!__btf_type_is_struct(member_type))
3133 if (member_type->size != sz)
3135 if (strcmp(__btf_name_by_offset(btf, member_type->name_off), name))
3138 /* only one such field is allowed */
3140 off = __btf_member_bit_offset(t, member);
3142 /* valid C code cannot generate such BTF */
3151 static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3152 const char *name, int sz, int align)
3154 const struct btf_var_secinfo *vsi;
3155 u32 i, off = -ENOENT;
3157 for_each_vsi(i, t, vsi) {
3158 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3159 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3161 if (!__btf_type_is_struct(var_type))
3163 if (var_type->size != sz)
3165 if (vsi->size != sz)
3167 if (strcmp(__btf_name_by_offset(btf, var_type->name_off), name))
3170 /* only one such field is allowed */
3179 static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3180 const char *name, int sz, int align)
3183 if (__btf_type_is_struct(t))
3184 return btf_find_struct_field(btf, t, name, sz, align);
3185 else if (btf_type_is_datasec(t))
3186 return btf_find_datasec_var(btf, t, name, sz, align);
3190 /* find 'struct bpf_spin_lock' in map value.
3191 * return >= 0 offset if found
3192 * and < 0 in case of error
3194 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
3196 return btf_find_field(btf, t, "bpf_spin_lock",
3197 sizeof(struct bpf_spin_lock),
3198 __alignof__(struct bpf_spin_lock));
3201 int btf_find_timer(const struct btf *btf, const struct btf_type *t)
3203 return btf_find_field(btf, t, "bpf_timer",
3204 sizeof(struct bpf_timer),
3205 __alignof__(struct bpf_timer));
3208 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3209 u32 type_id, void *data, u8 bits_offset,
3210 struct btf_show *show)
3212 const struct btf_member *member;
3216 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3220 for_each_member(i, t, member) {
3221 const struct btf_type *member_type = btf_type_by_id(btf,
3223 const struct btf_kind_operations *ops;
3224 u32 member_offset, bitfield_size;
3228 btf_show_start_member(show, member);
3230 member_offset = __btf_member_bit_offset(t, member);
3231 bitfield_size = __btf_member_bitfield_size(t, member);
3232 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3233 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3234 if (bitfield_size) {
3235 safe_data = btf_show_start_type(show, member_type,
3237 data + bytes_offset);
3239 btf_bitfield_show(safe_data,
3241 bitfield_size, show);
3242 btf_show_end_type(show);
3244 ops = btf_type_ops(member_type);
3245 ops->show(btf, member_type, member->type,
3246 data + bytes_offset, bits8_offset, show);
3249 btf_show_end_member(show);
3252 btf_show_end_struct_type(show);
3255 static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3256 u32 type_id, void *data, u8 bits_offset,
3257 struct btf_show *show)
3259 const struct btf_member *m = show->state.member;
3262 * First check if any members would be shown (are non-zero).
3263 * See comments above "struct btf_show" definition for more
3264 * details on how this works at a high-level.
3266 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3267 if (!show->state.depth_check) {
3268 show->state.depth_check = show->state.depth + 1;
3269 show->state.depth_to_show = 0;
3271 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3272 /* Restore saved member data here */
3273 show->state.member = m;
3274 if (show->state.depth_check != show->state.depth + 1)
3276 show->state.depth_check = 0;
3278 if (show->state.depth_to_show <= show->state.depth)
3281 * Reaching here indicates we have recursed and found
3282 * non-zero child values.
3286 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3289 static struct btf_kind_operations struct_ops = {
3290 .check_meta = btf_struct_check_meta,
3291 .resolve = btf_struct_resolve,
3292 .check_member = btf_struct_check_member,
3293 .check_kflag_member = btf_generic_check_kflag_member,
3294 .log_details = btf_struct_log,
3295 .show = btf_struct_show,
3298 static int btf_enum_check_member(struct btf_verifier_env *env,
3299 const struct btf_type *struct_type,
3300 const struct btf_member *member,
3301 const struct btf_type *member_type)
3303 u32 struct_bits_off = member->offset;
3304 u32 struct_size, bytes_offset;
3306 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3307 btf_verifier_log_member(env, struct_type, member,
3308 "Member is not byte aligned");
3312 struct_size = struct_type->size;
3313 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3314 if (struct_size - bytes_offset < member_type->size) {
3315 btf_verifier_log_member(env, struct_type, member,
3316 "Member exceeds struct_size");
3323 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3324 const struct btf_type *struct_type,
3325 const struct btf_member *member,
3326 const struct btf_type *member_type)
3328 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3329 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3331 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3332 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3334 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3335 btf_verifier_log_member(env, struct_type, member,
3336 "Member is not byte aligned");
3340 nr_bits = int_bitsize;
3341 } else if (nr_bits > int_bitsize) {
3342 btf_verifier_log_member(env, struct_type, member,
3343 "Invalid member bitfield_size");
3347 struct_size = struct_type->size;
3348 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3349 if (struct_size < bytes_end) {
3350 btf_verifier_log_member(env, struct_type, member,
3351 "Member exceeds struct_size");
3358 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3359 const struct btf_type *t,
3362 const struct btf_enum *enums = btf_type_enum(t);
3363 struct btf *btf = env->btf;
3367 nr_enums = btf_type_vlen(t);
3368 meta_needed = nr_enums * sizeof(*enums);
3370 if (meta_left < meta_needed) {
3371 btf_verifier_log_basic(env, t,
3372 "meta_left:%u meta_needed:%u",
3373 meta_left, meta_needed);
3377 if (btf_type_kflag(t)) {
3378 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3382 if (t->size > 8 || !is_power_of_2(t->size)) {
3383 btf_verifier_log_type(env, t, "Unexpected size");
3387 /* enum type either no name or a valid one */
3389 !btf_name_valid_identifier(env->btf, t->name_off)) {
3390 btf_verifier_log_type(env, t, "Invalid name");
3394 btf_verifier_log_type(env, t, NULL);
3396 for (i = 0; i < nr_enums; i++) {
3397 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3398 btf_verifier_log(env, "\tInvalid name_offset:%u",
3403 /* enum member must have a valid name */
3404 if (!enums[i].name_off ||
3405 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3406 btf_verifier_log_type(env, t, "Invalid name");
3410 if (env->log.level == BPF_LOG_KERNEL)
3412 btf_verifier_log(env, "\t%s val=%d\n",
3413 __btf_name_by_offset(btf, enums[i].name_off),
3420 static void btf_enum_log(struct btf_verifier_env *env,
3421 const struct btf_type *t)
3423 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3426 static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
3427 u32 type_id, void *data, u8 bits_offset,
3428 struct btf_show *show)
3430 const struct btf_enum *enums = btf_type_enum(t);
3431 u32 i, nr_enums = btf_type_vlen(t);
3435 safe_data = btf_show_start_type(show, t, type_id, data);
3439 v = *(int *)safe_data;
3441 for (i = 0; i < nr_enums; i++) {
3442 if (v != enums[i].val)
3445 btf_show_type_value(show, "%s",
3446 __btf_name_by_offset(btf,
3447 enums[i].name_off));
3449 btf_show_end_type(show);
3453 btf_show_type_value(show, "%d", v);
3454 btf_show_end_type(show);
3457 static struct btf_kind_operations enum_ops = {
3458 .check_meta = btf_enum_check_meta,
3459 .resolve = btf_df_resolve,
3460 .check_member = btf_enum_check_member,
3461 .check_kflag_member = btf_enum_check_kflag_member,
3462 .log_details = btf_enum_log,
3463 .show = btf_enum_show,
3466 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
3467 const struct btf_type *t,
3470 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
3472 if (meta_left < meta_needed) {
3473 btf_verifier_log_basic(env, t,
3474 "meta_left:%u meta_needed:%u",
3475 meta_left, meta_needed);
3480 btf_verifier_log_type(env, t, "Invalid name");
3484 if (btf_type_kflag(t)) {
3485 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3489 btf_verifier_log_type(env, t, NULL);
3494 static void btf_func_proto_log(struct btf_verifier_env *env,
3495 const struct btf_type *t)
3497 const struct btf_param *args = (const struct btf_param *)(t + 1);
3498 u16 nr_args = btf_type_vlen(t), i;
3500 btf_verifier_log(env, "return=%u args=(", t->type);
3502 btf_verifier_log(env, "void");
3506 if (nr_args == 1 && !args[0].type) {
3507 /* Only one vararg */
3508 btf_verifier_log(env, "vararg");
3512 btf_verifier_log(env, "%u %s", args[0].type,
3513 __btf_name_by_offset(env->btf,
3515 for (i = 1; i < nr_args - 1; i++)
3516 btf_verifier_log(env, ", %u %s", args[i].type,
3517 __btf_name_by_offset(env->btf,
3521 const struct btf_param *last_arg = &args[nr_args - 1];
3524 btf_verifier_log(env, ", %u %s", last_arg->type,
3525 __btf_name_by_offset(env->btf,
3526 last_arg->name_off));
3528 btf_verifier_log(env, ", vararg");
3532 btf_verifier_log(env, ")");
3535 static struct btf_kind_operations func_proto_ops = {
3536 .check_meta = btf_func_proto_check_meta,
3537 .resolve = btf_df_resolve,
3539 * BTF_KIND_FUNC_PROTO cannot be directly referred by
3540 * a struct's member.
3542 * It should be a function pointer instead.
3543 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
3545 * Hence, there is no btf_func_check_member().
3547 .check_member = btf_df_check_member,
3548 .check_kflag_member = btf_df_check_kflag_member,
3549 .log_details = btf_func_proto_log,
3550 .show = btf_df_show,
3553 static s32 btf_func_check_meta(struct btf_verifier_env *env,
3554 const struct btf_type *t,
3558 !btf_name_valid_identifier(env->btf, t->name_off)) {
3559 btf_verifier_log_type(env, t, "Invalid name");
3563 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
3564 btf_verifier_log_type(env, t, "Invalid func linkage");
3568 if (btf_type_kflag(t)) {
3569 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3573 btf_verifier_log_type(env, t, NULL);
3578 static int btf_func_resolve(struct btf_verifier_env *env,
3579 const struct resolve_vertex *v)
3581 const struct btf_type *t = v->t;
3582 u32 next_type_id = t->type;
3585 err = btf_func_check(env, t);
3589 env_stack_pop_resolved(env, next_type_id, 0);
3593 static struct btf_kind_operations func_ops = {
3594 .check_meta = btf_func_check_meta,
3595 .resolve = btf_func_resolve,
3596 .check_member = btf_df_check_member,
3597 .check_kflag_member = btf_df_check_kflag_member,
3598 .log_details = btf_ref_type_log,
3599 .show = btf_df_show,
3602 static s32 btf_var_check_meta(struct btf_verifier_env *env,
3603 const struct btf_type *t,
3606 const struct btf_var *var;
3607 u32 meta_needed = sizeof(*var);
3609 if (meta_left < meta_needed) {
3610 btf_verifier_log_basic(env, t,
3611 "meta_left:%u meta_needed:%u",
3612 meta_left, meta_needed);
3616 if (btf_type_vlen(t)) {
3617 btf_verifier_log_type(env, t, "vlen != 0");
3621 if (btf_type_kflag(t)) {
3622 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3627 !__btf_name_valid(env->btf, t->name_off, true)) {
3628 btf_verifier_log_type(env, t, "Invalid name");
3632 /* A var cannot be in type void */
3633 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
3634 btf_verifier_log_type(env, t, "Invalid type_id");
3638 var = btf_type_var(t);
3639 if (var->linkage != BTF_VAR_STATIC &&
3640 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
3641 btf_verifier_log_type(env, t, "Linkage not supported");
3645 btf_verifier_log_type(env, t, NULL);
3650 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
3652 const struct btf_var *var = btf_type_var(t);
3654 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
3657 static const struct btf_kind_operations var_ops = {
3658 .check_meta = btf_var_check_meta,
3659 .resolve = btf_var_resolve,
3660 .check_member = btf_df_check_member,
3661 .check_kflag_member = btf_df_check_kflag_member,
3662 .log_details = btf_var_log,
3663 .show = btf_var_show,
3666 static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
3667 const struct btf_type *t,
3670 const struct btf_var_secinfo *vsi;
3671 u64 last_vsi_end_off = 0, sum = 0;
3674 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
3675 if (meta_left < meta_needed) {
3676 btf_verifier_log_basic(env, t,
3677 "meta_left:%u meta_needed:%u",
3678 meta_left, meta_needed);
3683 btf_verifier_log_type(env, t, "size == 0");
3687 if (btf_type_kflag(t)) {
3688 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3693 !btf_name_valid_section(env->btf, t->name_off)) {
3694 btf_verifier_log_type(env, t, "Invalid name");
3698 btf_verifier_log_type(env, t, NULL);
3700 for_each_vsi(i, t, vsi) {
3701 /* A var cannot be in type void */
3702 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
3703 btf_verifier_log_vsi(env, t, vsi,
3708 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
3709 btf_verifier_log_vsi(env, t, vsi,
3714 if (!vsi->size || vsi->size > t->size) {
3715 btf_verifier_log_vsi(env, t, vsi,
3720 last_vsi_end_off = vsi->offset + vsi->size;
3721 if (last_vsi_end_off > t->size) {
3722 btf_verifier_log_vsi(env, t, vsi,
3723 "Invalid offset+size");
3727 btf_verifier_log_vsi(env, t, vsi, NULL);
3731 if (t->size < sum) {
3732 btf_verifier_log_type(env, t, "Invalid btf_info size");
3739 static int btf_datasec_resolve(struct btf_verifier_env *env,
3740 const struct resolve_vertex *v)
3742 const struct btf_var_secinfo *vsi;
3743 struct btf *btf = env->btf;
3746 for_each_vsi_from(i, v->next_member, v->t, vsi) {
3747 u32 var_type_id = vsi->type, type_id, type_size = 0;
3748 const struct btf_type *var_type = btf_type_by_id(env->btf,
3750 if (!var_type || !btf_type_is_var(var_type)) {
3751 btf_verifier_log_vsi(env, v->t, vsi,
3752 "Not a VAR kind member");
3756 if (!env_type_is_resolve_sink(env, var_type) &&
3757 !env_type_is_resolved(env, var_type_id)) {
3758 env_stack_set_next_member(env, i + 1);
3759 return env_stack_push(env, var_type, var_type_id);
3762 type_id = var_type->type;
3763 if (!btf_type_id_size(btf, &type_id, &type_size)) {
3764 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
3768 if (vsi->size < type_size) {
3769 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
3774 env_stack_pop_resolved(env, 0, 0);
3778 static void btf_datasec_log(struct btf_verifier_env *env,
3779 const struct btf_type *t)
3781 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3784 static void btf_datasec_show(const struct btf *btf,
3785 const struct btf_type *t, u32 type_id,
3786 void *data, u8 bits_offset,
3787 struct btf_show *show)
3789 const struct btf_var_secinfo *vsi;
3790 const struct btf_type *var;
3793 if (!btf_show_start_type(show, t, type_id, data))
3796 btf_show_type_value(show, "section (\"%s\") = {",
3797 __btf_name_by_offset(btf, t->name_off));
3798 for_each_vsi(i, t, vsi) {
3799 var = btf_type_by_id(btf, vsi->type);
3801 btf_show(show, ",");
3802 btf_type_ops(var)->show(btf, var, vsi->type,
3803 data + vsi->offset, bits_offset, show);
3805 btf_show_end_type(show);
3808 static const struct btf_kind_operations datasec_ops = {
3809 .check_meta = btf_datasec_check_meta,
3810 .resolve = btf_datasec_resolve,
3811 .check_member = btf_df_check_member,
3812 .check_kflag_member = btf_df_check_kflag_member,
3813 .log_details = btf_datasec_log,
3814 .show = btf_datasec_show,
3817 static s32 btf_float_check_meta(struct btf_verifier_env *env,
3818 const struct btf_type *t,
3821 if (btf_type_vlen(t)) {
3822 btf_verifier_log_type(env, t, "vlen != 0");
3826 if (btf_type_kflag(t)) {
3827 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3831 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
3833 btf_verifier_log_type(env, t, "Invalid type_size");
3837 btf_verifier_log_type(env, t, NULL);
3842 static int btf_float_check_member(struct btf_verifier_env *env,
3843 const struct btf_type *struct_type,
3844 const struct btf_member *member,
3845 const struct btf_type *member_type)
3847 u64 start_offset_bytes;
3848 u64 end_offset_bytes;
3853 /* Different architectures have different alignment requirements, so
3854 * here we check only for the reasonable minimum. This way we ensure
3855 * that types after CO-RE can pass the kernel BTF verifier.
3857 align_bytes = min_t(u64, sizeof(void *), member_type->size);
3858 align_bits = align_bytes * BITS_PER_BYTE;
3859 div64_u64_rem(member->offset, align_bits, &misalign_bits);
3860 if (misalign_bits) {
3861 btf_verifier_log_member(env, struct_type, member,
3862 "Member is not properly aligned");
3866 start_offset_bytes = member->offset / BITS_PER_BYTE;
3867 end_offset_bytes = start_offset_bytes + member_type->size;
3868 if (end_offset_bytes > struct_type->size) {
3869 btf_verifier_log_member(env, struct_type, member,
3870 "Member exceeds struct_size");
3877 static void btf_float_log(struct btf_verifier_env *env,
3878 const struct btf_type *t)
3880 btf_verifier_log(env, "size=%u", t->size);
3883 static const struct btf_kind_operations float_ops = {
3884 .check_meta = btf_float_check_meta,
3885 .resolve = btf_df_resolve,
3886 .check_member = btf_float_check_member,
3887 .check_kflag_member = btf_generic_check_kflag_member,
3888 .log_details = btf_float_log,
3889 .show = btf_df_show,
3892 static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
3893 const struct btf_type *t,
3896 const struct btf_decl_tag *tag;
3897 u32 meta_needed = sizeof(*tag);
3901 if (meta_left < meta_needed) {
3902 btf_verifier_log_basic(env, t,
3903 "meta_left:%u meta_needed:%u",
3904 meta_left, meta_needed);
3908 value = btf_name_by_offset(env->btf, t->name_off);
3909 if (!value || !value[0]) {
3910 btf_verifier_log_type(env, t, "Invalid value");
3914 if (btf_type_vlen(t)) {
3915 btf_verifier_log_type(env, t, "vlen != 0");
3919 if (btf_type_kflag(t)) {
3920 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3924 component_idx = btf_type_decl_tag(t)->component_idx;
3925 if (component_idx < -1) {
3926 btf_verifier_log_type(env, t, "Invalid component_idx");
3930 btf_verifier_log_type(env, t, NULL);
3935 static int btf_decl_tag_resolve(struct btf_verifier_env *env,
3936 const struct resolve_vertex *v)
3938 const struct btf_type *next_type;
3939 const struct btf_type *t = v->t;
3940 u32 next_type_id = t->type;
3941 struct btf *btf = env->btf;
3945 next_type = btf_type_by_id(btf, next_type_id);
3946 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
3947 btf_verifier_log_type(env, v->t, "Invalid type_id");
3951 if (!env_type_is_resolve_sink(env, next_type) &&
3952 !env_type_is_resolved(env, next_type_id))
3953 return env_stack_push(env, next_type, next_type_id);
3955 component_idx = btf_type_decl_tag(t)->component_idx;
3956 if (component_idx != -1) {
3957 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
3958 btf_verifier_log_type(env, v->t, "Invalid component_idx");
3962 if (btf_type_is_struct(next_type)) {
3963 vlen = btf_type_vlen(next_type);
3965 /* next_type should be a function */
3966 next_type = btf_type_by_id(btf, next_type->type);
3967 vlen = btf_type_vlen(next_type);
3970 if ((u32)component_idx >= vlen) {
3971 btf_verifier_log_type(env, v->t, "Invalid component_idx");
3976 env_stack_pop_resolved(env, next_type_id, 0);
3981 static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
3983 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
3984 btf_type_decl_tag(t)->component_idx);
3987 static const struct btf_kind_operations decl_tag_ops = {
3988 .check_meta = btf_decl_tag_check_meta,
3989 .resolve = btf_decl_tag_resolve,
3990 .check_member = btf_df_check_member,
3991 .check_kflag_member = btf_df_check_kflag_member,
3992 .log_details = btf_decl_tag_log,
3993 .show = btf_df_show,
3996 static int btf_func_proto_check(struct btf_verifier_env *env,
3997 const struct btf_type *t)
3999 const struct btf_type *ret_type;
4000 const struct btf_param *args;
4001 const struct btf *btf;
4006 args = (const struct btf_param *)(t + 1);
4007 nr_args = btf_type_vlen(t);
4009 /* Check func return type which could be "void" (t->type == 0) */
4011 u32 ret_type_id = t->type;
4013 ret_type = btf_type_by_id(btf, ret_type_id);
4015 btf_verifier_log_type(env, t, "Invalid return type");
4019 if (btf_type_needs_resolve(ret_type) &&
4020 !env_type_is_resolved(env, ret_type_id)) {
4021 err = btf_resolve(env, ret_type, ret_type_id);
4026 /* Ensure the return type is a type that has a size */
4027 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4028 btf_verifier_log_type(env, t, "Invalid return type");
4036 /* Last func arg type_id could be 0 if it is a vararg */
4037 if (!args[nr_args - 1].type) {
4038 if (args[nr_args - 1].name_off) {
4039 btf_verifier_log_type(env, t, "Invalid arg#%u",
4047 for (i = 0; i < nr_args; i++) {
4048 const struct btf_type *arg_type;
4051 arg_type_id = args[i].type;
4052 arg_type = btf_type_by_id(btf, arg_type_id);
4054 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4059 if (args[i].name_off &&
4060 (!btf_name_offset_valid(btf, args[i].name_off) ||
4061 !btf_name_valid_identifier(btf, args[i].name_off))) {
4062 btf_verifier_log_type(env, t,
4063 "Invalid arg#%u", i + 1);
4068 if (btf_type_needs_resolve(arg_type) &&
4069 !env_type_is_resolved(env, arg_type_id)) {
4070 err = btf_resolve(env, arg_type, arg_type_id);
4075 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4076 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4085 static int btf_func_check(struct btf_verifier_env *env,
4086 const struct btf_type *t)
4088 const struct btf_type *proto_type;
4089 const struct btf_param *args;
4090 const struct btf *btf;
4094 proto_type = btf_type_by_id(btf, t->type);
4096 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4097 btf_verifier_log_type(env, t, "Invalid type_id");
4101 args = (const struct btf_param *)(proto_type + 1);
4102 nr_args = btf_type_vlen(proto_type);
4103 for (i = 0; i < nr_args; i++) {
4104 if (!args[i].name_off && args[i].type) {
4105 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4113 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4114 [BTF_KIND_INT] = &int_ops,
4115 [BTF_KIND_PTR] = &ptr_ops,
4116 [BTF_KIND_ARRAY] = &array_ops,
4117 [BTF_KIND_STRUCT] = &struct_ops,
4118 [BTF_KIND_UNION] = &struct_ops,
4119 [BTF_KIND_ENUM] = &enum_ops,
4120 [BTF_KIND_FWD] = &fwd_ops,
4121 [BTF_KIND_TYPEDEF] = &modifier_ops,
4122 [BTF_KIND_VOLATILE] = &modifier_ops,
4123 [BTF_KIND_CONST] = &modifier_ops,
4124 [BTF_KIND_RESTRICT] = &modifier_ops,
4125 [BTF_KIND_FUNC] = &func_ops,
4126 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4127 [BTF_KIND_VAR] = &var_ops,
4128 [BTF_KIND_DATASEC] = &datasec_ops,
4129 [BTF_KIND_FLOAT] = &float_ops,
4130 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4131 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4134 static s32 btf_check_meta(struct btf_verifier_env *env,
4135 const struct btf_type *t,
4138 u32 saved_meta_left = meta_left;
4141 if (meta_left < sizeof(*t)) {
4142 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4143 env->log_type_id, meta_left, sizeof(*t));
4146 meta_left -= sizeof(*t);
4148 if (t->info & ~BTF_INFO_MASK) {
4149 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4150 env->log_type_id, t->info);
4154 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4155 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4156 btf_verifier_log(env, "[%u] Invalid kind:%u",
4157 env->log_type_id, BTF_INFO_KIND(t->info));
4161 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4162 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4163 env->log_type_id, t->name_off);
4167 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4168 if (var_meta_size < 0)
4169 return var_meta_size;
4171 meta_left -= var_meta_size;
4173 return saved_meta_left - meta_left;
4176 static int btf_check_all_metas(struct btf_verifier_env *env)
4178 struct btf *btf = env->btf;
4179 struct btf_header *hdr;
4183 cur = btf->nohdr_data + hdr->type_off;
4184 end = cur + hdr->type_len;
4186 env->log_type_id = btf->base_btf ? btf->start_id : 1;
4188 struct btf_type *t = cur;
4191 meta_size = btf_check_meta(env, t, end - cur);
4195 btf_add_type(env, t);
4203 static bool btf_resolve_valid(struct btf_verifier_env *env,
4204 const struct btf_type *t,
4207 struct btf *btf = env->btf;
4209 if (!env_type_is_resolved(env, type_id))
4212 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
4213 return !btf_resolved_type_id(btf, type_id) &&
4214 !btf_resolved_type_size(btf, type_id);
4216 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
4217 return btf_resolved_type_id(btf, type_id) &&
4218 !btf_resolved_type_size(btf, type_id);
4220 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
4221 btf_type_is_var(t)) {
4222 t = btf_type_id_resolve(btf, &type_id);
4224 !btf_type_is_modifier(t) &&
4225 !btf_type_is_var(t) &&
4226 !btf_type_is_datasec(t);
4229 if (btf_type_is_array(t)) {
4230 const struct btf_array *array = btf_type_array(t);
4231 const struct btf_type *elem_type;
4232 u32 elem_type_id = array->type;
4235 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
4236 return elem_type && !btf_type_is_modifier(elem_type) &&
4237 (array->nelems * elem_size ==
4238 btf_resolved_type_size(btf, type_id));
4244 static int btf_resolve(struct btf_verifier_env *env,
4245 const struct btf_type *t, u32 type_id)
4247 u32 save_log_type_id = env->log_type_id;
4248 const struct resolve_vertex *v;
4251 env->resolve_mode = RESOLVE_TBD;
4252 env_stack_push(env, t, type_id);
4253 while (!err && (v = env_stack_peak(env))) {
4254 env->log_type_id = v->type_id;
4255 err = btf_type_ops(v->t)->resolve(env, v);
4258 env->log_type_id = type_id;
4259 if (err == -E2BIG) {
4260 btf_verifier_log_type(env, t,
4261 "Exceeded max resolving depth:%u",
4263 } else if (err == -EEXIST) {
4264 btf_verifier_log_type(env, t, "Loop detected");
4267 /* Final sanity check */
4268 if (!err && !btf_resolve_valid(env, t, type_id)) {
4269 btf_verifier_log_type(env, t, "Invalid resolve state");
4273 env->log_type_id = save_log_type_id;
4277 static int btf_check_all_types(struct btf_verifier_env *env)
4279 struct btf *btf = env->btf;
4280 const struct btf_type *t;
4284 err = env_resolve_init(env);
4289 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
4290 type_id = btf->start_id + i;
4291 t = btf_type_by_id(btf, type_id);
4293 env->log_type_id = type_id;
4294 if (btf_type_needs_resolve(t) &&
4295 !env_type_is_resolved(env, type_id)) {
4296 err = btf_resolve(env, t, type_id);
4301 if (btf_type_is_func_proto(t)) {
4302 err = btf_func_proto_check(env, t);
4311 static int btf_parse_type_sec(struct btf_verifier_env *env)
4313 const struct btf_header *hdr = &env->btf->hdr;
4316 /* Type section must align to 4 bytes */
4317 if (hdr->type_off & (sizeof(u32) - 1)) {
4318 btf_verifier_log(env, "Unaligned type_off");
4322 if (!env->btf->base_btf && !hdr->type_len) {
4323 btf_verifier_log(env, "No type found");
4327 err = btf_check_all_metas(env);
4331 return btf_check_all_types(env);
4334 static int btf_parse_str_sec(struct btf_verifier_env *env)
4336 const struct btf_header *hdr;
4337 struct btf *btf = env->btf;
4338 const char *start, *end;
4341 start = btf->nohdr_data + hdr->str_off;
4342 end = start + hdr->str_len;
4344 if (end != btf->data + btf->data_size) {
4345 btf_verifier_log(env, "String section is not at the end");
4349 btf->strings = start;
4351 if (btf->base_btf && !hdr->str_len)
4353 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
4354 btf_verifier_log(env, "Invalid string section");
4357 if (!btf->base_btf && start[0]) {
4358 btf_verifier_log(env, "Invalid string section");
4365 static const size_t btf_sec_info_offset[] = {
4366 offsetof(struct btf_header, type_off),
4367 offsetof(struct btf_header, str_off),
4370 static int btf_sec_info_cmp(const void *a, const void *b)
4372 const struct btf_sec_info *x = a;
4373 const struct btf_sec_info *y = b;
4375 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
4378 static int btf_check_sec_info(struct btf_verifier_env *env,
4381 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
4382 u32 total, expected_total, i;
4383 const struct btf_header *hdr;
4384 const struct btf *btf;
4389 /* Populate the secs from hdr */
4390 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
4391 secs[i] = *(struct btf_sec_info *)((void *)hdr +
4392 btf_sec_info_offset[i]);
4394 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
4395 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
4397 /* Check for gaps and overlap among sections */
4399 expected_total = btf_data_size - hdr->hdr_len;
4400 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
4401 if (expected_total < secs[i].off) {
4402 btf_verifier_log(env, "Invalid section offset");
4405 if (total < secs[i].off) {
4407 btf_verifier_log(env, "Unsupported section found");
4410 if (total > secs[i].off) {
4411 btf_verifier_log(env, "Section overlap found");
4414 if (expected_total - total < secs[i].len) {
4415 btf_verifier_log(env,
4416 "Total section length too long");
4419 total += secs[i].len;
4422 /* There is data other than hdr and known sections */
4423 if (expected_total != total) {
4424 btf_verifier_log(env, "Unsupported section found");
4431 static int btf_parse_hdr(struct btf_verifier_env *env)
4433 u32 hdr_len, hdr_copy, btf_data_size;
4434 const struct btf_header *hdr;
4439 btf_data_size = btf->data_size;
4442 offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) {
4443 btf_verifier_log(env, "hdr_len not found");
4448 hdr_len = hdr->hdr_len;
4449 if (btf_data_size < hdr_len) {
4450 btf_verifier_log(env, "btf_header not found");
4454 /* Ensure the unsupported header fields are zero */
4455 if (hdr_len > sizeof(btf->hdr)) {
4456 u8 *expected_zero = btf->data + sizeof(btf->hdr);
4457 u8 *end = btf->data + hdr_len;
4459 for (; expected_zero < end; expected_zero++) {
4460 if (*expected_zero) {
4461 btf_verifier_log(env, "Unsupported btf_header");
4467 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
4468 memcpy(&btf->hdr, btf->data, hdr_copy);
4472 btf_verifier_log_hdr(env, btf_data_size);
4474 if (hdr->magic != BTF_MAGIC) {
4475 btf_verifier_log(env, "Invalid magic");
4479 if (hdr->version != BTF_VERSION) {
4480 btf_verifier_log(env, "Unsupported version");
4485 btf_verifier_log(env, "Unsupported flags");
4489 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
4490 btf_verifier_log(env, "No data");
4494 err = btf_check_sec_info(env, btf_data_size);
4501 static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
4502 u32 log_level, char __user *log_ubuf, u32 log_size)
4504 struct btf_verifier_env *env = NULL;
4505 struct bpf_verifier_log *log;
4506 struct btf *btf = NULL;
4510 if (btf_data_size > BTF_MAX_SIZE)
4511 return ERR_PTR(-E2BIG);
4513 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4515 return ERR_PTR(-ENOMEM);
4518 if (log_level || log_ubuf || log_size) {
4519 /* user requested verbose verifier output
4520 * and supplied buffer to store the verification trace
4522 log->level = log_level;
4523 log->ubuf = log_ubuf;
4524 log->len_total = log_size;
4526 /* log attributes have to be sane */
4527 if (!bpf_verifier_log_attr_valid(log)) {
4533 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4540 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
4547 btf->data_size = btf_data_size;
4549 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
4554 err = btf_parse_hdr(env);
4558 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4560 err = btf_parse_str_sec(env);
4564 err = btf_parse_type_sec(env);
4568 if (log->level && bpf_verifier_log_full(log)) {
4573 btf_verifier_env_free(env);
4574 refcount_set(&btf->refcnt, 1);
4578 btf_verifier_env_free(env);
4581 return ERR_PTR(err);
4584 extern char __weak __start_BTF[];
4585 extern char __weak __stop_BTF[];
4586 extern struct btf *btf_vmlinux;
4588 #define BPF_MAP_TYPE(_id, _ops)
4589 #define BPF_LINK_TYPE(_id, _name)
4591 struct bpf_ctx_convert {
4592 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4593 prog_ctx_type _id##_prog; \
4594 kern_ctx_type _id##_kern;
4595 #include <linux/bpf_types.h>
4596 #undef BPF_PROG_TYPE
4598 /* 't' is written once under lock. Read many times. */
4599 const struct btf_type *t;
4602 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4604 #include <linux/bpf_types.h>
4605 #undef BPF_PROG_TYPE
4606 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
4608 static u8 bpf_ctx_convert_map[] = {
4609 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4610 [_id] = __ctx_convert##_id,
4611 #include <linux/bpf_types.h>
4612 #undef BPF_PROG_TYPE
4613 0, /* avoid empty array */
4616 #undef BPF_LINK_TYPE
4618 static const struct btf_member *
4619 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
4620 const struct btf_type *t, enum bpf_prog_type prog_type,
4623 const struct btf_type *conv_struct;
4624 const struct btf_type *ctx_struct;
4625 const struct btf_member *ctx_type;
4626 const char *tname, *ctx_tname;
4628 conv_struct = bpf_ctx_convert.t;
4630 bpf_log(log, "btf_vmlinux is malformed\n");
4633 t = btf_type_by_id(btf, t->type);
4634 while (btf_type_is_modifier(t))
4635 t = btf_type_by_id(btf, t->type);
4636 if (!btf_type_is_struct(t)) {
4637 /* Only pointer to struct is supported for now.
4638 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
4639 * is not supported yet.
4640 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
4644 tname = btf_name_by_offset(btf, t->name_off);
4646 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
4649 /* prog_type is valid bpf program type. No need for bounds check. */
4650 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
4651 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
4652 * Like 'struct __sk_buff'
4654 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
4656 /* should not happen */
4658 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
4660 /* should not happen */
4661 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
4664 /* only compare that prog's ctx type name is the same as
4665 * kernel expects. No need to compare field by field.
4666 * It's ok for bpf prog to do:
4667 * struct __sk_buff {};
4668 * int socket_filter_bpf_prog(struct __sk_buff *skb)
4669 * { // no fields of skb are ever used }
4671 if (strcmp(ctx_tname, tname))
4676 static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = {
4677 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
4678 #define BPF_LINK_TYPE(_id, _name)
4679 #define BPF_MAP_TYPE(_id, _ops) \
4681 #include <linux/bpf_types.h>
4682 #undef BPF_PROG_TYPE
4683 #undef BPF_LINK_TYPE
4687 static int btf_vmlinux_map_ids_init(const struct btf *btf,
4688 struct bpf_verifier_log *log)
4690 const struct bpf_map_ops *ops;
4693 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) {
4694 ops = btf_vmlinux_map_ops[i];
4695 if (!ops || (!ops->map_btf_name && !ops->map_btf_id))
4697 if (!ops->map_btf_name || !ops->map_btf_id) {
4698 bpf_log(log, "map type %d is misconfigured\n", i);
4701 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name,
4705 *ops->map_btf_id = btf_id;
4711 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
4713 const struct btf_type *t,
4714 enum bpf_prog_type prog_type,
4717 const struct btf_member *prog_ctx_type, *kern_ctx_type;
4719 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
4722 kern_ctx_type = prog_ctx_type + 1;
4723 return kern_ctx_type->type;
4726 BTF_ID_LIST(bpf_ctx_convert_btf_id)
4727 BTF_ID(struct, bpf_ctx_convert)
4729 struct btf *btf_parse_vmlinux(void)
4731 struct btf_verifier_env *env = NULL;
4732 struct bpf_verifier_log *log;
4733 struct btf *btf = NULL;
4736 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4738 return ERR_PTR(-ENOMEM);
4741 log->level = BPF_LOG_KERNEL;
4743 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4750 btf->data = __start_BTF;
4751 btf->data_size = __stop_BTF - __start_BTF;
4752 btf->kernel_btf = true;
4753 snprintf(btf->name, sizeof(btf->name), "vmlinux");
4755 err = btf_parse_hdr(env);
4759 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4761 err = btf_parse_str_sec(env);
4765 err = btf_check_all_metas(env);
4769 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
4770 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
4772 /* find bpf map structs for map_ptr access checking */
4773 err = btf_vmlinux_map_ids_init(btf, log);
4777 bpf_struct_ops_init(btf, log);
4779 refcount_set(&btf->refcnt, 1);
4781 err = btf_alloc_id(btf);
4785 btf_verifier_env_free(env);
4789 btf_verifier_env_free(env);
4794 return ERR_PTR(err);
4797 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
4799 static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
4801 struct btf_verifier_env *env = NULL;
4802 struct bpf_verifier_log *log;
4803 struct btf *btf = NULL, *base_btf;
4806 base_btf = bpf_get_btf_vmlinux();
4807 if (IS_ERR(base_btf))
4810 return ERR_PTR(-EINVAL);
4812 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4814 return ERR_PTR(-ENOMEM);
4817 log->level = BPF_LOG_KERNEL;
4819 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4826 btf->base_btf = base_btf;
4827 btf->start_id = base_btf->nr_types;
4828 btf->start_str_off = base_btf->hdr.str_len;
4829 btf->kernel_btf = true;
4830 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
4832 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
4837 memcpy(btf->data, data, data_size);
4838 btf->data_size = data_size;
4840 err = btf_parse_hdr(env);
4844 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4846 err = btf_parse_str_sec(env);
4850 err = btf_check_all_metas(env);
4854 btf_verifier_env_free(env);
4855 refcount_set(&btf->refcnt, 1);
4859 btf_verifier_env_free(env);
4865 return ERR_PTR(err);
4868 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
4870 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
4872 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4875 return tgt_prog->aux->btf;
4877 return prog->aux->attach_btf;
4880 static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
4882 /* t comes in already as a pointer */
4883 t = btf_type_by_id(btf, t->type);
4886 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
4887 t = btf_type_by_id(btf, t->type);
4889 return btf_type_is_int(t);
4892 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
4893 const struct bpf_prog *prog,
4894 struct bpf_insn_access_aux *info)
4896 const struct btf_type *t = prog->aux->attach_func_proto;
4897 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
4898 struct btf *btf = bpf_prog_get_target_btf(prog);
4899 const char *tname = prog->aux->attach_func_name;
4900 struct bpf_verifier_log *log = info->log;
4901 const struct btf_param *args;
4902 const char *tag_value;
4907 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
4912 args = (const struct btf_param *)(t + 1);
4913 /* if (t == NULL) Fall back to default BPF prog with
4914 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
4916 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
4917 if (prog->aux->attach_btf_trace) {
4918 /* skip first 'void *__data' argument in btf_trace_##name typedef */
4923 if (arg > nr_args) {
4924 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4929 if (arg == nr_args) {
4930 switch (prog->expected_attach_type) {
4932 case BPF_TRACE_FEXIT:
4933 /* When LSM programs are attached to void LSM hooks
4934 * they use FEXIT trampolines and when attached to
4935 * int LSM hooks, they use MODIFY_RETURN trampolines.
4937 * While the LSM programs are BPF_MODIFY_RETURN-like
4940 * if (ret_type != 'int')
4943 * is _not_ done here. This is still safe as LSM hooks
4944 * have only void and int return types.
4948 t = btf_type_by_id(btf, t->type);
4950 case BPF_MODIFY_RETURN:
4951 /* For now the BPF_MODIFY_RETURN can only be attached to
4952 * functions that return an int.
4957 t = btf_type_skip_modifiers(btf, t->type, NULL);
4958 if (!btf_type_is_small_int(t)) {
4960 "ret type %s not allowed for fmod_ret\n",
4961 btf_kind_str[BTF_INFO_KIND(t->info)]);
4966 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
4972 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
4974 t = btf_type_by_id(btf, args[arg].type);
4977 /* skip modifiers */
4978 while (btf_type_is_modifier(t))
4979 t = btf_type_by_id(btf, t->type);
4980 if (btf_type_is_small_int(t) || btf_type_is_enum(t))
4981 /* accessing a scalar */
4983 if (!btf_type_is_ptr(t)) {
4985 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
4987 __btf_name_by_offset(btf, t->name_off),
4988 btf_kind_str[BTF_INFO_KIND(t->info)]);
4992 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
4993 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
4994 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
4997 type = base_type(ctx_arg_info->reg_type);
4998 flag = type_flag(ctx_arg_info->reg_type);
4999 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
5000 (flag & PTR_MAYBE_NULL)) {
5001 info->reg_type = ctx_arg_info->reg_type;
5007 /* This is a pointer to void.
5008 * It is the same as scalar from the verifier safety pov.
5009 * No further pointer walking is allowed.
5013 if (is_int_ptr(btf, t))
5016 /* this is a pointer to another type */
5017 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5018 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5020 if (ctx_arg_info->offset == off) {
5021 if (!ctx_arg_info->btf_id) {
5022 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
5026 info->reg_type = ctx_arg_info->reg_type;
5027 info->btf = btf_vmlinux;
5028 info->btf_id = ctx_arg_info->btf_id;
5033 info->reg_type = PTR_TO_BTF_ID;
5035 enum bpf_prog_type tgt_type;
5037 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
5038 tgt_type = tgt_prog->aux->saved_dst_prog_type;
5040 tgt_type = tgt_prog->type;
5042 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
5044 info->btf = btf_vmlinux;
5053 info->btf_id = t->type;
5054 t = btf_type_by_id(btf, t->type);
5056 if (btf_type_is_type_tag(t)) {
5057 tag_value = __btf_name_by_offset(btf, t->name_off);
5058 if (strcmp(tag_value, "user") == 0)
5059 info->reg_type |= MEM_USER;
5062 /* skip modifiers */
5063 while (btf_type_is_modifier(t)) {
5064 info->btf_id = t->type;
5065 t = btf_type_by_id(btf, t->type);
5067 if (!btf_type_is_struct(t)) {
5069 "func '%s' arg%d type %s is not a struct\n",
5070 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]);
5073 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
5074 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)],
5075 __btf_name_by_offset(btf, t->name_off));
5079 enum bpf_struct_walk_result {
5086 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
5087 const struct btf_type *t, int off, int size,
5088 u32 *next_btf_id, enum bpf_type_flag *flag)
5090 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
5091 const struct btf_type *mtype, *elem_type = NULL;
5092 const struct btf_member *member;
5093 const char *tname, *mname, *tag_value;
5094 u32 vlen, elem_id, mid;
5097 tname = __btf_name_by_offset(btf, t->name_off);
5098 if (!btf_type_is_struct(t)) {
5099 bpf_log(log, "Type '%s' is not a struct\n", tname);
5103 vlen = btf_type_vlen(t);
5104 if (off + size > t->size) {
5105 /* If the last element is a variable size array, we may
5106 * need to relax the rule.
5108 struct btf_array *array_elem;
5113 member = btf_type_member(t) + vlen - 1;
5114 mtype = btf_type_skip_modifiers(btf, member->type,
5116 if (!btf_type_is_array(mtype))
5119 array_elem = (struct btf_array *)(mtype + 1);
5120 if (array_elem->nelems != 0)
5123 moff = __btf_member_bit_offset(t, member) / 8;
5127 /* Only allow structure for now, can be relaxed for
5128 * other types later.
5130 t = btf_type_skip_modifiers(btf, array_elem->type,
5132 if (!btf_type_is_struct(t))
5135 off = (off - moff) % t->size;
5139 bpf_log(log, "access beyond struct %s at off %u size %u\n",
5144 for_each_member(i, t, member) {
5145 /* offset of the field in bytes */
5146 moff = __btf_member_bit_offset(t, member) / 8;
5147 if (off + size <= moff)
5148 /* won't find anything, field is already too far */
5151 if (__btf_member_bitfield_size(t, member)) {
5152 u32 end_bit = __btf_member_bit_offset(t, member) +
5153 __btf_member_bitfield_size(t, member);
5155 /* off <= moff instead of off == moff because clang
5156 * does not generate a BTF member for anonymous
5157 * bitfield like the ":16" here:
5164 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
5167 /* off may be accessing a following member
5171 * Doing partial access at either end of this
5172 * bitfield. Continue on this case also to
5173 * treat it as not accessing this bitfield
5174 * and eventually error out as field not
5175 * found to keep it simple.
5176 * It could be relaxed if there was a legit
5177 * partial access case later.
5182 /* In case of "off" is pointing to holes of a struct */
5186 /* type of the field */
5188 mtype = btf_type_by_id(btf, member->type);
5189 mname = __btf_name_by_offset(btf, member->name_off);
5191 mtype = __btf_resolve_size(btf, mtype, &msize,
5192 &elem_type, &elem_id, &total_nelems,
5194 if (IS_ERR(mtype)) {
5195 bpf_log(log, "field %s doesn't have size\n", mname);
5199 mtrue_end = moff + msize;
5200 if (off >= mtrue_end)
5201 /* no overlap with member, keep iterating */
5204 if (btf_type_is_array(mtype)) {
5207 /* __btf_resolve_size() above helps to
5208 * linearize a multi-dimensional array.
5210 * The logic here is treating an array
5211 * in a struct as the following way:
5214 * struct inner array[2][2];
5220 * struct inner array_elem0;
5221 * struct inner array_elem1;
5222 * struct inner array_elem2;
5223 * struct inner array_elem3;
5226 * When accessing outer->array[1][0], it moves
5227 * moff to "array_elem2", set mtype to
5228 * "struct inner", and msize also becomes
5229 * sizeof(struct inner). Then most of the
5230 * remaining logic will fall through without
5231 * caring the current member is an array or
5234 * Unlike mtype/msize/moff, mtrue_end does not
5235 * change. The naming difference ("_true") tells
5236 * that it is not always corresponding to
5237 * the current mtype/msize/moff.
5238 * It is the true end of the current
5239 * member (i.e. array in this case). That
5240 * will allow an int array to be accessed like
5242 * i.e. allow access beyond the size of
5243 * the array's element as long as it is
5244 * within the mtrue_end boundary.
5247 /* skip empty array */
5248 if (moff == mtrue_end)
5251 msize /= total_nelems;
5252 elem_idx = (off - moff) / msize;
5253 moff += elem_idx * msize;
5258 /* the 'off' we're looking for is either equal to start
5259 * of this field or inside of this struct
5261 if (btf_type_is_struct(mtype)) {
5262 /* our field must be inside that union or struct */
5265 /* return if the offset matches the member offset */
5271 /* adjust offset we're looking for */
5276 if (btf_type_is_ptr(mtype)) {
5277 const struct btf_type *stype, *t;
5278 enum bpf_type_flag tmp_flag = 0;
5281 if (msize != size || off != moff) {
5283 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
5284 mname, moff, tname, off, size);
5288 /* check __user tag */
5289 t = btf_type_by_id(btf, mtype->type);
5290 if (btf_type_is_type_tag(t)) {
5291 tag_value = __btf_name_by_offset(btf, t->name_off);
5292 if (strcmp(tag_value, "user") == 0)
5293 tmp_flag = MEM_USER;
5296 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
5297 if (btf_type_is_struct(stype)) {
5304 /* Allow more flexible access within an int as long as
5305 * it is within mtrue_end.
5306 * Since mtrue_end could be the end of an array,
5307 * that also allows using an array of int as a scratch
5308 * space. e.g. skb->cb[].
5310 if (off + size > mtrue_end) {
5312 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
5313 mname, mtrue_end, tname, off, size);
5319 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
5323 int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
5324 const struct btf_type *t, int off, int size,
5325 enum bpf_access_type atype __maybe_unused,
5326 u32 *next_btf_id, enum bpf_type_flag *flag)
5328 enum bpf_type_flag tmp_flag = 0;
5333 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
5337 /* If we found the pointer or scalar on t+off,
5342 return PTR_TO_BTF_ID;
5344 return SCALAR_VALUE;
5346 /* We found nested struct, so continue the search
5347 * by diving in it. At this point the offset is
5348 * aligned with the new type, so set it to 0.
5350 t = btf_type_by_id(btf, id);
5354 /* It's either error or unknown return value..
5357 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
5366 /* Check that two BTF types, each specified as an BTF object + id, are exactly
5367 * the same. Trivial ID check is not enough due to module BTFs, because we can
5368 * end up with two different module BTFs, but IDs point to the common type in
5371 static bool btf_types_are_same(const struct btf *btf1, u32 id1,
5372 const struct btf *btf2, u32 id2)
5378 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
5381 bool btf_struct_ids_match(struct bpf_verifier_log *log,
5382 const struct btf *btf, u32 id, int off,
5383 const struct btf *need_btf, u32 need_type_id)
5385 const struct btf_type *type;
5386 enum bpf_type_flag flag;
5389 /* Are we already done? */
5390 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
5394 type = btf_type_by_id(btf, id);
5397 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag);
5398 if (err != WALK_STRUCT)
5401 /* We found nested struct object. If it matches
5402 * the requested ID, we're done. Otherwise let's
5403 * continue the search with offset 0 in the new
5406 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
5414 static int __get_type_size(struct btf *btf, u32 btf_id,
5415 const struct btf_type **bad_type)
5417 const struct btf_type *t;
5422 t = btf_type_by_id(btf, btf_id);
5423 while (t && btf_type_is_modifier(t))
5424 t = btf_type_by_id(btf, t->type);
5426 *bad_type = btf_type_by_id(btf, 0);
5429 if (btf_type_is_ptr(t))
5430 /* kernel size of pointer. Not BPF's size of pointer*/
5431 return sizeof(void *);
5432 if (btf_type_is_int(t) || btf_type_is_enum(t))
5438 int btf_distill_func_proto(struct bpf_verifier_log *log,
5440 const struct btf_type *func,
5442 struct btf_func_model *m)
5444 const struct btf_param *args;
5445 const struct btf_type *t;
5450 /* BTF function prototype doesn't match the verifier types.
5451 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
5453 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
5456 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
5459 args = (const struct btf_param *)(func + 1);
5460 nargs = btf_type_vlen(func);
5461 if (nargs >= MAX_BPF_FUNC_ARGS) {
5463 "The function %s has %d arguments. Too many.\n",
5467 ret = __get_type_size(btf, func->type, &t);
5470 "The function %s return type %s is unsupported.\n",
5471 tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
5476 for (i = 0; i < nargs; i++) {
5477 if (i == nargs - 1 && args[i].type == 0) {
5479 "The function %s with variable args is unsupported.\n",
5483 ret = __get_type_size(btf, args[i].type, &t);
5486 "The function %s arg%d type %s is unsupported.\n",
5487 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
5492 "The function %s has malformed void argument.\n",
5496 m->arg_size[i] = ret;
5502 /* Compare BTFs of two functions assuming only scalars and pointers to context.
5503 * t1 points to BTF_KIND_FUNC in btf1
5504 * t2 points to BTF_KIND_FUNC in btf2
5506 * EINVAL - function prototype mismatch
5507 * EFAULT - verifier bug
5508 * 0 - 99% match. The last 1% is validated by the verifier.
5510 static int btf_check_func_type_match(struct bpf_verifier_log *log,
5511 struct btf *btf1, const struct btf_type *t1,
5512 struct btf *btf2, const struct btf_type *t2)
5514 const struct btf_param *args1, *args2;
5515 const char *fn1, *fn2, *s1, *s2;
5516 u32 nargs1, nargs2, i;
5518 fn1 = btf_name_by_offset(btf1, t1->name_off);
5519 fn2 = btf_name_by_offset(btf2, t2->name_off);
5521 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
5522 bpf_log(log, "%s() is not a global function\n", fn1);
5525 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
5526 bpf_log(log, "%s() is not a global function\n", fn2);
5530 t1 = btf_type_by_id(btf1, t1->type);
5531 if (!t1 || !btf_type_is_func_proto(t1))
5533 t2 = btf_type_by_id(btf2, t2->type);
5534 if (!t2 || !btf_type_is_func_proto(t2))
5537 args1 = (const struct btf_param *)(t1 + 1);
5538 nargs1 = btf_type_vlen(t1);
5539 args2 = (const struct btf_param *)(t2 + 1);
5540 nargs2 = btf_type_vlen(t2);
5542 if (nargs1 != nargs2) {
5543 bpf_log(log, "%s() has %d args while %s() has %d args\n",
5544 fn1, nargs1, fn2, nargs2);
5548 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5549 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5550 if (t1->info != t2->info) {
5552 "Return type %s of %s() doesn't match type %s of %s()\n",
5553 btf_type_str(t1), fn1,
5554 btf_type_str(t2), fn2);
5558 for (i = 0; i < nargs1; i++) {
5559 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
5560 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
5562 if (t1->info != t2->info) {
5563 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
5564 i, fn1, btf_type_str(t1),
5565 fn2, btf_type_str(t2));
5568 if (btf_type_has_size(t1) && t1->size != t2->size) {
5570 "arg%d in %s() has size %d while %s() has %d\n",
5576 /* global functions are validated with scalars and pointers
5577 * to context only. And only global functions can be replaced.
5578 * Hence type check only those types.
5580 if (btf_type_is_int(t1) || btf_type_is_enum(t1))
5582 if (!btf_type_is_ptr(t1)) {
5584 "arg%d in %s() has unrecognized type\n",
5588 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5589 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5590 if (!btf_type_is_struct(t1)) {
5592 "arg%d in %s() is not a pointer to context\n",
5596 if (!btf_type_is_struct(t2)) {
5598 "arg%d in %s() is not a pointer to context\n",
5602 /* This is an optional check to make program writing easier.
5603 * Compare names of structs and report an error to the user.
5604 * btf_prepare_func_args() already checked that t2 struct
5605 * is a context type. btf_prepare_func_args() will check
5606 * later that t1 struct is a context type as well.
5608 s1 = btf_name_by_offset(btf1, t1->name_off);
5609 s2 = btf_name_by_offset(btf2, t2->name_off);
5610 if (strcmp(s1, s2)) {
5612 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
5613 i, fn1, s1, fn2, s2);
5620 /* Compare BTFs of given program with BTF of target program */
5621 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
5622 struct btf *btf2, const struct btf_type *t2)
5624 struct btf *btf1 = prog->aux->btf;
5625 const struct btf_type *t1;
5628 if (!prog->aux->func_info) {
5629 bpf_log(log, "Program extension requires BTF\n");
5633 btf_id = prog->aux->func_info[0].type_id;
5637 t1 = btf_type_by_id(btf1, btf_id);
5638 if (!t1 || !btf_type_is_func(t1))
5641 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
5644 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
5646 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
5647 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
5648 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
5652 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
5653 static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
5654 const struct btf *btf,
5655 const struct btf_type *t, int rec)
5657 const struct btf_type *member_type;
5658 const struct btf_member *member;
5661 if (!btf_type_is_struct(t))
5664 for_each_member(i, t, member) {
5665 const struct btf_array *array;
5667 member_type = btf_type_skip_modifiers(btf, member->type, NULL);
5668 if (btf_type_is_struct(member_type)) {
5670 bpf_log(log, "max struct nesting depth exceeded\n");
5673 if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
5677 if (btf_type_is_array(member_type)) {
5678 array = btf_type_array(member_type);
5681 member_type = btf_type_skip_modifiers(btf, array->type, NULL);
5682 if (!btf_type_is_scalar(member_type))
5686 if (!btf_type_is_scalar(member_type))
5692 static bool is_kfunc_arg_mem_size(const struct btf *btf,
5693 const struct btf_param *arg,
5694 const struct bpf_reg_state *reg)
5696 int len, sfx_len = sizeof("__sz") - 1;
5697 const struct btf_type *t;
5698 const char *param_name;
5700 t = btf_type_skip_modifiers(btf, arg->type, NULL);
5701 if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
5704 /* In the future, this can be ported to use BTF tagging */
5705 param_name = btf_name_by_offset(btf, arg->name_off);
5706 if (str_is_empty(param_name))
5708 len = strlen(param_name);
5711 param_name += len - sfx_len;
5712 if (strncmp(param_name, "__sz", sfx_len))
5718 static int btf_check_func_arg_match(struct bpf_verifier_env *env,
5719 const struct btf *btf, u32 func_id,
5720 struct bpf_reg_state *regs,
5723 struct bpf_verifier_log *log = &env->log;
5724 u32 i, nargs, ref_id, ref_obj_id = 0;
5725 bool is_kfunc = btf_is_kernel(btf);
5726 const char *func_name, *ref_tname;
5727 const struct btf_type *t, *ref_t;
5728 const struct btf_param *args;
5732 t = btf_type_by_id(btf, func_id);
5733 if (!t || !btf_type_is_func(t)) {
5734 /* These checks were already done by the verifier while loading
5735 * struct bpf_func_info or in add_kfunc_call().
5737 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
5741 func_name = btf_name_by_offset(btf, t->name_off);
5743 t = btf_type_by_id(btf, t->type);
5744 if (!t || !btf_type_is_func_proto(t)) {
5745 bpf_log(log, "Invalid BTF of func %s\n", func_name);
5748 args = (const struct btf_param *)(t + 1);
5749 nargs = btf_type_vlen(t);
5750 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
5751 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
5752 MAX_BPF_FUNC_REG_ARGS);
5756 /* check that BTF function arguments match actual types that the
5759 for (i = 0; i < nargs; i++) {
5761 struct bpf_reg_state *reg = ®s[regno];
5763 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
5764 if (btf_type_is_scalar(t)) {
5765 if (reg->type == SCALAR_VALUE)
5767 bpf_log(log, "R%d is not a scalar\n", regno);
5771 if (!btf_type_is_ptr(t)) {
5772 bpf_log(log, "Unrecognized arg#%d type %s\n",
5773 i, btf_type_str(t));
5777 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
5778 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
5779 if (btf_get_prog_ctx_type(log, btf, t,
5780 env->prog->type, i)) {
5781 /* If function expects ctx type in BTF check that caller
5782 * is passing PTR_TO_CTX.
5784 if (reg->type != PTR_TO_CTX) {
5786 "arg#%d expected pointer to ctx, but got %s\n",
5787 i, btf_type_str(t));
5790 if (check_ptr_off_reg(env, reg, regno))
5792 } else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
5793 (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
5794 const struct btf_type *reg_ref_t;
5795 const struct btf *reg_btf;
5796 const char *reg_ref_tname;
5799 if (!btf_type_is_struct(ref_t)) {
5800 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
5801 func_name, i, btf_type_str(ref_t),
5806 if (reg->type == PTR_TO_BTF_ID) {
5808 reg_ref_id = reg->btf_id;
5809 /* Ensure only one argument is referenced PTR_TO_BTF_ID */
5810 if (reg->ref_obj_id) {
5812 bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
5813 regno, reg->ref_obj_id, ref_obj_id);
5817 ref_obj_id = reg->ref_obj_id;
5820 reg_btf = btf_vmlinux;
5821 reg_ref_id = *reg2btf_ids[base_type(reg->type)];
5824 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
5826 reg_ref_tname = btf_name_by_offset(reg_btf,
5827 reg_ref_t->name_off);
5828 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
5829 reg->off, btf, ref_id)) {
5830 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
5832 btf_type_str(ref_t), ref_tname,
5833 regno, btf_type_str(reg_ref_t),
5837 } else if (ptr_to_mem_ok) {
5838 const struct btf_type *resolve_ret;
5842 bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]);
5844 /* Permit pointer to mem, but only when argument
5845 * type is pointer to scalar, or struct composed
5846 * (recursively) of scalars.
5847 * When arg_mem_size is true, the pointer can be
5850 if (!btf_type_is_scalar(ref_t) &&
5851 !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
5852 (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
5854 "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
5855 i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
5859 /* Check for mem, len pair */
5861 if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) {
5862 bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
5871 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
5872 if (IS_ERR(resolve_ret)) {
5874 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
5875 i, btf_type_str(ref_t), ref_tname,
5876 PTR_ERR(resolve_ret));
5880 if (check_mem_reg(env, reg, regno, type_size))
5883 bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
5884 is_kfunc ? "kernel " : "", func_name, func_id);
5889 /* Either both are set, or neither */
5890 WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
5892 rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog),
5893 BTF_KFUNC_TYPE_RELEASE, func_id);
5894 /* We already made sure ref_obj_id is set only for one argument */
5895 if (rel && !ref_obj_id) {
5896 bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
5900 /* Allow (!rel && ref_obj_id), so that passing such referenced PTR_TO_BTF_ID to
5901 * other kfuncs works
5904 /* returns argument register number > 0 in case of reference release kfunc */
5905 return rel ? ref_regno : 0;
5908 /* Compare BTF of a function with given bpf_reg_state.
5910 * EFAULT - there is a verifier bug. Abort verification.
5911 * EINVAL - there is a type mismatch or BTF is not available.
5912 * 0 - BTF matches with what bpf_reg_state expects.
5913 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
5915 int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
5916 struct bpf_reg_state *regs)
5918 struct bpf_prog *prog = env->prog;
5919 struct btf *btf = prog->aux->btf;
5924 if (!prog->aux->func_info)
5927 btf_id = prog->aux->func_info[subprog].type_id;
5931 if (prog->aux->func_info_aux[subprog].unreliable)
5934 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
5935 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global);
5937 /* Compiler optimizations can remove arguments from static functions
5938 * or mismatched type can be passed into a global function.
5939 * In such cases mark the function as unreliable from BTF point of view.
5942 prog->aux->func_info_aux[subprog].unreliable = true;
5946 int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
5947 const struct btf *btf, u32 func_id,
5948 struct bpf_reg_state *regs)
5950 return btf_check_func_arg_match(env, btf, func_id, regs, true);
5953 /* Convert BTF of a function into bpf_reg_state if possible
5955 * EFAULT - there is a verifier bug. Abort verification.
5956 * EINVAL - cannot convert BTF.
5957 * 0 - Successfully converted BTF into bpf_reg_state
5958 * (either PTR_TO_CTX or SCALAR_VALUE).
5960 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
5961 struct bpf_reg_state *regs)
5963 struct bpf_verifier_log *log = &env->log;
5964 struct bpf_prog *prog = env->prog;
5965 enum bpf_prog_type prog_type = prog->type;
5966 struct btf *btf = prog->aux->btf;
5967 const struct btf_param *args;
5968 const struct btf_type *t, *ref_t;
5969 u32 i, nargs, btf_id;
5972 if (!prog->aux->func_info ||
5973 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
5974 bpf_log(log, "Verifier bug\n");
5978 btf_id = prog->aux->func_info[subprog].type_id;
5980 bpf_log(log, "Global functions need valid BTF\n");
5984 t = btf_type_by_id(btf, btf_id);
5985 if (!t || !btf_type_is_func(t)) {
5986 /* These checks were already done by the verifier while loading
5987 * struct bpf_func_info
5989 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
5993 tname = btf_name_by_offset(btf, t->name_off);
5995 if (log->level & BPF_LOG_LEVEL)
5996 bpf_log(log, "Validating %s() func#%d...\n",
5999 if (prog->aux->func_info_aux[subprog].unreliable) {
6000 bpf_log(log, "Verifier bug in function %s()\n", tname);
6003 if (prog_type == BPF_PROG_TYPE_EXT)
6004 prog_type = prog->aux->dst_prog->type;
6006 t = btf_type_by_id(btf, t->type);
6007 if (!t || !btf_type_is_func_proto(t)) {
6008 bpf_log(log, "Invalid type of function %s()\n", tname);
6011 args = (const struct btf_param *)(t + 1);
6012 nargs = btf_type_vlen(t);
6013 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6014 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
6015 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
6018 /* check that function returns int */
6019 t = btf_type_by_id(btf, t->type);
6020 while (btf_type_is_modifier(t))
6021 t = btf_type_by_id(btf, t->type);
6022 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) {
6024 "Global function %s() doesn't return scalar. Only those are supported.\n",
6028 /* Convert BTF function arguments into verifier types.
6029 * Only PTR_TO_CTX and SCALAR are supported atm.
6031 for (i = 0; i < nargs; i++) {
6032 struct bpf_reg_state *reg = ®s[i + 1];
6034 t = btf_type_by_id(btf, args[i].type);
6035 while (btf_type_is_modifier(t))
6036 t = btf_type_by_id(btf, t->type);
6037 if (btf_type_is_int(t) || btf_type_is_enum(t)) {
6038 reg->type = SCALAR_VALUE;
6041 if (btf_type_is_ptr(t)) {
6042 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6043 reg->type = PTR_TO_CTX;
6047 t = btf_type_skip_modifiers(btf, t->type, NULL);
6049 ref_t = btf_resolve_size(btf, t, ®->mem_size);
6050 if (IS_ERR(ref_t)) {
6052 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6053 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
6058 reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
6059 reg->id = ++env->id_gen;
6063 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
6064 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname);
6070 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
6071 struct btf_show *show)
6073 const struct btf_type *t = btf_type_by_id(btf, type_id);
6076 memset(&show->state, 0, sizeof(show->state));
6077 memset(&show->obj, 0, sizeof(show->obj));
6079 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
6082 static void btf_seq_show(struct btf_show *show, const char *fmt,
6085 seq_vprintf((struct seq_file *)show->target, fmt, args);
6088 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
6089 void *obj, struct seq_file *m, u64 flags)
6091 struct btf_show sseq;
6094 sseq.showfn = btf_seq_show;
6097 btf_type_show(btf, type_id, obj, &sseq);
6099 return sseq.state.status;
6102 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
6105 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
6106 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
6107 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
6110 struct btf_show_snprintf {
6111 struct btf_show show;
6112 int len_left; /* space left in string */
6113 int len; /* length we would have written */
6116 static void btf_snprintf_show(struct btf_show *show, const char *fmt,
6119 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
6122 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
6125 ssnprintf->len_left = 0;
6126 ssnprintf->len = len;
6127 } else if (len > ssnprintf->len_left) {
6128 /* no space, drive on to get length we would have written */
6129 ssnprintf->len_left = 0;
6130 ssnprintf->len += len;
6132 ssnprintf->len_left -= len;
6133 ssnprintf->len += len;
6134 show->target += len;
6138 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
6139 char *buf, int len, u64 flags)
6141 struct btf_show_snprintf ssnprintf;
6143 ssnprintf.show.target = buf;
6144 ssnprintf.show.flags = flags;
6145 ssnprintf.show.showfn = btf_snprintf_show;
6146 ssnprintf.len_left = len;
6149 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
6151 /* If we encontered an error, return it. */
6152 if (ssnprintf.show.state.status)
6153 return ssnprintf.show.state.status;
6155 /* Otherwise return length we would have written */
6156 return ssnprintf.len;
6159 #ifdef CONFIG_PROC_FS
6160 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
6162 const struct btf *btf = filp->private_data;
6164 seq_printf(m, "btf_id:\t%u\n", btf->id);
6168 static int btf_release(struct inode *inode, struct file *filp)
6170 btf_put(filp->private_data);
6174 const struct file_operations btf_fops = {
6175 #ifdef CONFIG_PROC_FS
6176 .show_fdinfo = bpf_btf_show_fdinfo,
6178 .release = btf_release,
6181 static int __btf_new_fd(struct btf *btf)
6183 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
6186 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
6191 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
6192 attr->btf_size, attr->btf_log_level,
6193 u64_to_user_ptr(attr->btf_log_buf),
6194 attr->btf_log_size);
6196 return PTR_ERR(btf);
6198 ret = btf_alloc_id(btf);
6205 * The BTF ID is published to the userspace.
6206 * All BTF free must go through call_rcu() from
6207 * now on (i.e. free by calling btf_put()).
6210 ret = __btf_new_fd(btf);
6217 struct btf *btf_get_by_fd(int fd)
6225 return ERR_PTR(-EBADF);
6227 if (f.file->f_op != &btf_fops) {
6229 return ERR_PTR(-EINVAL);
6232 btf = f.file->private_data;
6233 refcount_inc(&btf->refcnt);
6239 int btf_get_info_by_fd(const struct btf *btf,
6240 const union bpf_attr *attr,
6241 union bpf_attr __user *uattr)
6243 struct bpf_btf_info __user *uinfo;
6244 struct bpf_btf_info info;
6245 u32 info_copy, btf_copy;
6248 u32 uinfo_len, uname_len, name_len;
6251 uinfo = u64_to_user_ptr(attr->info.info);
6252 uinfo_len = attr->info.info_len;
6254 info_copy = min_t(u32, uinfo_len, sizeof(info));
6255 memset(&info, 0, sizeof(info));
6256 if (copy_from_user(&info, uinfo, info_copy))
6260 ubtf = u64_to_user_ptr(info.btf);
6261 btf_copy = min_t(u32, btf->data_size, info.btf_size);
6262 if (copy_to_user(ubtf, btf->data, btf_copy))
6264 info.btf_size = btf->data_size;
6266 info.kernel_btf = btf->kernel_btf;
6268 uname = u64_to_user_ptr(info.name);
6269 uname_len = info.name_len;
6270 if (!uname ^ !uname_len)
6273 name_len = strlen(btf->name);
6274 info.name_len = name_len;
6277 if (uname_len >= name_len + 1) {
6278 if (copy_to_user(uname, btf->name, name_len + 1))
6283 if (copy_to_user(uname, btf->name, uname_len - 1))
6285 if (put_user(zero, uname + uname_len - 1))
6287 /* let user-space know about too short buffer */
6292 if (copy_to_user(uinfo, &info, info_copy) ||
6293 put_user(info_copy, &uattr->info.info_len))
6299 int btf_get_fd_by_id(u32 id)
6305 btf = idr_find(&btf_idr, id);
6306 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
6307 btf = ERR_PTR(-ENOENT);
6311 return PTR_ERR(btf);
6313 fd = __btf_new_fd(btf);
6320 u32 btf_obj_id(const struct btf *btf)
6325 bool btf_is_kernel(const struct btf *btf)
6327 return btf->kernel_btf;
6330 bool btf_is_module(const struct btf *btf)
6332 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
6335 static int btf_id_cmp_func(const void *a, const void *b)
6337 const int *pa = a, *pb = b;
6342 bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
6344 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
6348 BTF_MODULE_F_LIVE = (1 << 0),
6351 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6353 struct list_head list;
6354 struct module *module;
6356 struct bin_attribute *sysfs_attr;
6360 static LIST_HEAD(btf_modules);
6361 static DEFINE_MUTEX(btf_module_mutex);
6364 btf_module_read(struct file *file, struct kobject *kobj,
6365 struct bin_attribute *bin_attr,
6366 char *buf, loff_t off, size_t len)
6368 const struct btf *btf = bin_attr->private;
6370 memcpy(buf, btf->data + off, len);
6374 static void purge_cand_cache(struct btf *btf);
6376 static int btf_module_notify(struct notifier_block *nb, unsigned long op,
6379 struct btf_module *btf_mod, *tmp;
6380 struct module *mod = module;
6384 if (mod->btf_data_size == 0 ||
6385 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
6386 op != MODULE_STATE_GOING))
6390 case MODULE_STATE_COMING:
6391 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
6396 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
6398 pr_warn("failed to validate module [%s] BTF: %ld\n",
6399 mod->name, PTR_ERR(btf));
6404 err = btf_alloc_id(btf);
6411 purge_cand_cache(NULL);
6412 mutex_lock(&btf_module_mutex);
6413 btf_mod->module = module;
6415 list_add(&btf_mod->list, &btf_modules);
6416 mutex_unlock(&btf_module_mutex);
6418 if (IS_ENABLED(CONFIG_SYSFS)) {
6419 struct bin_attribute *attr;
6421 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
6425 sysfs_bin_attr_init(attr);
6426 attr->attr.name = btf->name;
6427 attr->attr.mode = 0444;
6428 attr->size = btf->data_size;
6429 attr->private = btf;
6430 attr->read = btf_module_read;
6432 err = sysfs_create_bin_file(btf_kobj, attr);
6434 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
6441 btf_mod->sysfs_attr = attr;
6445 case MODULE_STATE_LIVE:
6446 mutex_lock(&btf_module_mutex);
6447 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6448 if (btf_mod->module != module)
6451 btf_mod->flags |= BTF_MODULE_F_LIVE;
6454 mutex_unlock(&btf_module_mutex);
6456 case MODULE_STATE_GOING:
6457 mutex_lock(&btf_module_mutex);
6458 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6459 if (btf_mod->module != module)
6462 list_del(&btf_mod->list);
6463 if (btf_mod->sysfs_attr)
6464 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
6465 purge_cand_cache(btf_mod->btf);
6466 btf_put(btf_mod->btf);
6467 kfree(btf_mod->sysfs_attr);
6471 mutex_unlock(&btf_module_mutex);
6475 return notifier_from_errno(err);
6478 static struct notifier_block btf_module_nb = {
6479 .notifier_call = btf_module_notify,
6482 static int __init btf_module_init(void)
6484 register_module_notifier(&btf_module_nb);
6488 fs_initcall(btf_module_init);
6489 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6491 struct module *btf_try_get_module(const struct btf *btf)
6493 struct module *res = NULL;
6494 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6495 struct btf_module *btf_mod, *tmp;
6497 mutex_lock(&btf_module_mutex);
6498 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6499 if (btf_mod->btf != btf)
6502 /* We must only consider module whose __init routine has
6503 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
6504 * which is set from the notifier callback for
6505 * MODULE_STATE_LIVE.
6507 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
6508 res = btf_mod->module;
6512 mutex_unlock(&btf_module_mutex);
6518 /* Returns struct btf corresponding to the struct module
6520 * This function can return NULL or ERR_PTR. Note that caller must
6521 * release reference for struct btf iff btf_is_module is true.
6523 static struct btf *btf_get_module_btf(const struct module *module)
6525 struct btf *btf = NULL;
6526 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6527 struct btf_module *btf_mod, *tmp;
6531 return bpf_get_btf_vmlinux();
6532 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6533 mutex_lock(&btf_module_mutex);
6534 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6535 if (btf_mod->module != module)
6538 btf_get(btf_mod->btf);
6542 mutex_unlock(&btf_module_mutex);
6548 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
6556 if (name_sz <= 1 || name[name_sz - 1])
6559 btf = bpf_get_btf_vmlinux();
6561 return PTR_ERR(btf);
6563 ret = btf_find_by_name_kind(btf, name, kind);
6564 /* ret is never zero, since btf_find_by_name_kind returns
6565 * positive btf_id or negative error.
6568 struct btf *mod_btf;
6571 /* If name is not found in vmlinux's BTF then search in module's BTFs */
6572 spin_lock_bh(&btf_idr_lock);
6573 idr_for_each_entry(&btf_idr, mod_btf, id) {
6574 if (!btf_is_module(mod_btf))
6576 /* linear search could be slow hence unlock/lock
6577 * the IDR to avoiding holding it for too long
6580 spin_unlock_bh(&btf_idr_lock);
6581 ret = btf_find_by_name_kind(mod_btf, name, kind);
6585 btf_obj_fd = __btf_new_fd(mod_btf);
6586 if (btf_obj_fd < 0) {
6590 return ret | (((u64)btf_obj_fd) << 32);
6592 spin_lock_bh(&btf_idr_lock);
6595 spin_unlock_bh(&btf_idr_lock);
6600 const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
6601 .func = bpf_btf_find_by_name_kind,
6603 .ret_type = RET_INTEGER,
6604 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
6605 .arg2_type = ARG_CONST_SIZE,
6606 .arg3_type = ARG_ANYTHING,
6607 .arg4_type = ARG_ANYTHING,
6610 BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
6611 #define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
6612 BTF_TRACING_TYPE_xxx
6613 #undef BTF_TRACING_TYPE
6615 /* Kernel Function (kfunc) BTF ID set registration API */
6617 static int __btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
6618 enum btf_kfunc_type type,
6619 struct btf_id_set *add_set, bool vmlinux_set)
6621 struct btf_kfunc_set_tab *tab;
6622 struct btf_id_set *set;
6626 if (hook >= BTF_KFUNC_HOOK_MAX || type >= BTF_KFUNC_TYPE_MAX) {
6634 tab = btf->kfunc_set_tab;
6636 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
6639 btf->kfunc_set_tab = tab;
6642 set = tab->sets[hook][type];
6643 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
6646 if (WARN_ON_ONCE(set && !vmlinux_set)) {
6651 /* We don't need to allocate, concatenate, and sort module sets, because
6652 * only one is allowed per hook. Hence, we can directly assign the
6653 * pointer and return.
6656 tab->sets[hook][type] = add_set;
6660 /* In case of vmlinux sets, there may be more than one set being
6661 * registered per hook. To create a unified set, we allocate a new set
6662 * and concatenate all individual sets being registered. While each set
6663 * is individually sorted, they may become unsorted when concatenated,
6664 * hence re-sorting the final set again is required to make binary
6665 * searching the set using btf_id_set_contains function work.
6667 set_cnt = set ? set->cnt : 0;
6669 if (set_cnt > U32_MAX - add_set->cnt) {
6674 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
6680 set = krealloc(tab->sets[hook][type],
6681 offsetof(struct btf_id_set, ids[set_cnt + add_set->cnt]),
6682 GFP_KERNEL | __GFP_NOWARN);
6688 /* For newly allocated set, initialize set->cnt to 0 */
6689 if (!tab->sets[hook][type])
6691 tab->sets[hook][type] = set;
6693 /* Concatenate the two sets */
6694 memcpy(set->ids + set->cnt, add_set->ids, add_set->cnt * sizeof(set->ids[0]));
6695 set->cnt += add_set->cnt;
6697 sort(set->ids, set->cnt, sizeof(set->ids[0]), btf_id_cmp_func, NULL);
6701 btf_free_kfunc_set_tab(btf);
6705 static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
6706 const struct btf_kfunc_id_set *kset)
6708 bool vmlinux_set = !btf_is_module(btf);
6711 for (type = 0; type < ARRAY_SIZE(kset->sets); type++) {
6712 if (!kset->sets[type])
6715 ret = __btf_populate_kfunc_set(btf, hook, type, kset->sets[type], vmlinux_set);
6722 static bool __btf_kfunc_id_set_contains(const struct btf *btf,
6723 enum btf_kfunc_hook hook,
6724 enum btf_kfunc_type type,
6727 struct btf_id_set *set;
6729 if (hook >= BTF_KFUNC_HOOK_MAX || type >= BTF_KFUNC_TYPE_MAX)
6731 if (!btf->kfunc_set_tab)
6733 set = btf->kfunc_set_tab->sets[hook][type];
6736 return btf_id_set_contains(set, kfunc_btf_id);
6739 static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
6741 switch (prog_type) {
6742 case BPF_PROG_TYPE_XDP:
6743 return BTF_KFUNC_HOOK_XDP;
6744 case BPF_PROG_TYPE_SCHED_CLS:
6745 return BTF_KFUNC_HOOK_TC;
6746 case BPF_PROG_TYPE_STRUCT_OPS:
6747 return BTF_KFUNC_HOOK_STRUCT_OPS;
6749 return BTF_KFUNC_HOOK_MAX;
6754 * Reference to the module (obtained using btf_try_get_module) corresponding to
6755 * the struct btf *MUST* be held when calling this function from verifier
6756 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
6757 * keeping the reference for the duration of the call provides the necessary
6758 * protection for looking up a well-formed btf->kfunc_set_tab.
6760 bool btf_kfunc_id_set_contains(const struct btf *btf,
6761 enum bpf_prog_type prog_type,
6762 enum btf_kfunc_type type, u32 kfunc_btf_id)
6764 enum btf_kfunc_hook hook;
6766 hook = bpf_prog_type_to_kfunc_hook(prog_type);
6767 return __btf_kfunc_id_set_contains(btf, hook, type, kfunc_btf_id);
6770 /* This function must be invoked only from initcalls/module init functions */
6771 int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
6772 const struct btf_kfunc_id_set *kset)
6774 enum btf_kfunc_hook hook;
6778 btf = btf_get_module_btf(kset->owner);
6780 if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
6781 pr_err("missing vmlinux BTF, cannot register kfuncs\n");
6784 if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
6785 pr_err("missing module BTF, cannot register kfuncs\n");
6791 return PTR_ERR(btf);
6793 hook = bpf_prog_type_to_kfunc_hook(prog_type);
6794 ret = btf_populate_kfunc_set(btf, hook, kset);
6795 /* reference is only taken for module BTF */
6796 if (btf_is_module(btf))
6800 EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
6802 #define MAX_TYPES_ARE_COMPAT_DEPTH 2
6805 int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
6806 const struct btf *targ_btf, __u32 targ_id,
6809 const struct btf_type *local_type, *targ_type;
6810 int depth = 32; /* max recursion depth */
6812 /* caller made sure that names match (ignoring flavor suffix) */
6813 local_type = btf_type_by_id(local_btf, local_id);
6814 targ_type = btf_type_by_id(targ_btf, targ_id);
6815 if (btf_kind(local_type) != btf_kind(targ_type))
6823 local_type = btf_type_skip_modifiers(local_btf, local_id, &local_id);
6824 targ_type = btf_type_skip_modifiers(targ_btf, targ_id, &targ_id);
6825 if (!local_type || !targ_type)
6828 if (btf_kind(local_type) != btf_kind(targ_type))
6831 switch (btf_kind(local_type)) {
6833 case BTF_KIND_STRUCT:
6834 case BTF_KIND_UNION:
6839 /* just reject deprecated bitfield-like integers; all other
6840 * integers are by default compatible between each other
6842 return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0;
6844 local_id = local_type->type;
6845 targ_id = targ_type->type;
6847 case BTF_KIND_ARRAY:
6848 local_id = btf_array(local_type)->type;
6849 targ_id = btf_array(targ_type)->type;
6851 case BTF_KIND_FUNC_PROTO: {
6852 struct btf_param *local_p = btf_params(local_type);
6853 struct btf_param *targ_p = btf_params(targ_type);
6854 __u16 local_vlen = btf_vlen(local_type);
6855 __u16 targ_vlen = btf_vlen(targ_type);
6858 if (local_vlen != targ_vlen)
6861 for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
6865 btf_type_skip_modifiers(local_btf, local_p->type, &local_id);
6866 btf_type_skip_modifiers(targ_btf, targ_p->type, &targ_id);
6867 err = __bpf_core_types_are_compat(local_btf, local_id,
6874 /* tail recurse for return type check */
6875 btf_type_skip_modifiers(local_btf, local_type->type, &local_id);
6876 btf_type_skip_modifiers(targ_btf, targ_type->type, &targ_id);
6884 /* Check local and target types for compatibility. This check is used for
6885 * type-based CO-RE relocations and follow slightly different rules than
6886 * field-based relocations. This function assumes that root types were already
6887 * checked for name match. Beyond that initial root-level name check, names
6888 * are completely ignored. Compatibility rules are as follows:
6889 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but
6890 * kind should match for local and target types (i.e., STRUCT is not
6891 * compatible with UNION);
6892 * - for ENUMs, the size is ignored;
6893 * - for INT, size and signedness are ignored;
6894 * - for ARRAY, dimensionality is ignored, element types are checked for
6895 * compatibility recursively;
6896 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
6897 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
6898 * - FUNC_PROTOs are compatible if they have compatible signature: same
6899 * number of input args and compatible return and argument types.
6900 * These rules are not set in stone and probably will be adjusted as we get
6901 * more experience with using BPF CO-RE relocations.
6903 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
6904 const struct btf *targ_btf, __u32 targ_id)
6906 return __bpf_core_types_are_compat(local_btf, local_id,
6908 MAX_TYPES_ARE_COMPAT_DEPTH);
6911 static bool bpf_core_is_flavor_sep(const char *s)
6913 /* check X___Y name pattern, where X and Y are not underscores */
6914 return s[0] != '_' && /* X */
6915 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
6916 s[4] != '_'; /* Y */
6919 size_t bpf_core_essential_name_len(const char *name)
6921 size_t n = strlen(name);
6924 for (i = n - 5; i >= 0; i--) {
6925 if (bpf_core_is_flavor_sep(name + i))
6931 struct bpf_cand_cache {
6937 const struct btf *btf;
6942 static void bpf_free_cands(struct bpf_cand_cache *cands)
6945 /* empty candidate array was allocated on stack */
6950 static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
6956 #define VMLINUX_CAND_CACHE_SIZE 31
6957 static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
6959 #define MODULE_CAND_CACHE_SIZE 31
6960 static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
6962 static DEFINE_MUTEX(cand_cache_mutex);
6964 static void __print_cand_cache(struct bpf_verifier_log *log,
6965 struct bpf_cand_cache **cache,
6968 struct bpf_cand_cache *cc;
6971 for (i = 0; i < cache_size; i++) {
6975 bpf_log(log, "[%d]%s(", i, cc->name);
6976 for (j = 0; j < cc->cnt; j++) {
6977 bpf_log(log, "%d", cc->cands[j].id);
6978 if (j < cc->cnt - 1)
6981 bpf_log(log, "), ");
6985 static void print_cand_cache(struct bpf_verifier_log *log)
6987 mutex_lock(&cand_cache_mutex);
6988 bpf_log(log, "vmlinux_cand_cache:");
6989 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
6990 bpf_log(log, "\nmodule_cand_cache:");
6991 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
6993 mutex_unlock(&cand_cache_mutex);
6996 static u32 hash_cands(struct bpf_cand_cache *cands)
6998 return jhash(cands->name, cands->name_len, 0);
7001 static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
7002 struct bpf_cand_cache **cache,
7005 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
7007 if (cc && cc->name_len == cands->name_len &&
7008 !strncmp(cc->name, cands->name, cands->name_len))
7013 static size_t sizeof_cands(int cnt)
7015 return offsetof(struct bpf_cand_cache, cands[cnt]);
7018 static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
7019 struct bpf_cand_cache **cache,
7022 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
7025 bpf_free_cands_from_cache(*cc);
7028 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
7030 bpf_free_cands(cands);
7031 return ERR_PTR(-ENOMEM);
7033 /* strdup the name, since it will stay in cache.
7034 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
7036 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
7037 bpf_free_cands(cands);
7038 if (!new_cands->name) {
7040 return ERR_PTR(-ENOMEM);
7046 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7047 static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
7050 struct bpf_cand_cache *cc;
7053 for (i = 0; i < cache_size; i++) {
7058 /* when new module is loaded purge all of module_cand_cache,
7059 * since new module might have candidates with the name
7060 * that matches cached cands.
7062 bpf_free_cands_from_cache(cc);
7066 /* when module is unloaded purge cache entries
7067 * that match module's btf
7069 for (j = 0; j < cc->cnt; j++)
7070 if (cc->cands[j].btf == btf) {
7071 bpf_free_cands_from_cache(cc);
7079 static void purge_cand_cache(struct btf *btf)
7081 mutex_lock(&cand_cache_mutex);
7082 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7083 mutex_unlock(&cand_cache_mutex);
7087 static struct bpf_cand_cache *
7088 bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
7091 struct bpf_cand_cache *new_cands;
7092 const struct btf_type *t;
7093 const char *targ_name;
7094 size_t targ_essent_len;
7097 n = btf_nr_types(targ_btf);
7098 for (i = targ_start_id; i < n; i++) {
7099 t = btf_type_by_id(targ_btf, i);
7100 if (btf_kind(t) != cands->kind)
7103 targ_name = btf_name_by_offset(targ_btf, t->name_off);
7107 /* the resched point is before strncmp to make sure that search
7108 * for non-existing name will have a chance to schedule().
7112 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
7115 targ_essent_len = bpf_core_essential_name_len(targ_name);
7116 if (targ_essent_len != cands->name_len)
7119 /* most of the time there is only one candidate for a given kind+name pair */
7120 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
7122 bpf_free_cands(cands);
7123 return ERR_PTR(-ENOMEM);
7126 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
7127 bpf_free_cands(cands);
7129 cands->cands[cands->cnt].btf = targ_btf;
7130 cands->cands[cands->cnt].id = i;
7136 static struct bpf_cand_cache *
7137 bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
7139 struct bpf_cand_cache *cands, *cc, local_cand = {};
7140 const struct btf *local_btf = ctx->btf;
7141 const struct btf_type *local_type;
7142 const struct btf *main_btf;
7143 size_t local_essent_len;
7144 struct btf *mod_btf;
7148 main_btf = bpf_get_btf_vmlinux();
7149 if (IS_ERR(main_btf))
7150 return ERR_CAST(main_btf);
7152 local_type = btf_type_by_id(local_btf, local_type_id);
7154 return ERR_PTR(-EINVAL);
7156 name = btf_name_by_offset(local_btf, local_type->name_off);
7157 if (str_is_empty(name))
7158 return ERR_PTR(-EINVAL);
7159 local_essent_len = bpf_core_essential_name_len(name);
7161 cands = &local_cand;
7163 cands->kind = btf_kind(local_type);
7164 cands->name_len = local_essent_len;
7166 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7167 /* cands is a pointer to stack here */
7174 /* Attempt to find target candidates in vmlinux BTF first */
7175 cands = bpf_core_add_cands(cands, main_btf, 1);
7177 return ERR_CAST(cands);
7179 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
7181 /* populate cache even when cands->cnt == 0 */
7182 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7184 return ERR_CAST(cc);
7186 /* if vmlinux BTF has any candidate, don't go for module BTFs */
7191 /* cands is a pointer to stack here and cands->cnt == 0 */
7192 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7194 /* if cache has it return it even if cc->cnt == 0 */
7197 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
7198 spin_lock_bh(&btf_idr_lock);
7199 idr_for_each_entry(&btf_idr, mod_btf, id) {
7200 if (!btf_is_module(mod_btf))
7202 /* linear search could be slow hence unlock/lock
7203 * the IDR to avoiding holding it for too long
7206 spin_unlock_bh(&btf_idr_lock);
7207 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
7208 if (IS_ERR(cands)) {
7210 return ERR_CAST(cands);
7212 spin_lock_bh(&btf_idr_lock);
7215 spin_unlock_bh(&btf_idr_lock);
7216 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
7217 * or pointer to stack if cands->cnd == 0.
7218 * Copy it into the cache even when cands->cnt == 0 and
7219 * return the result.
7221 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7224 int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
7225 int relo_idx, void *insn)
7227 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
7228 struct bpf_core_cand_list cands = {};
7229 struct bpf_core_relo_res targ_res;
7230 struct bpf_core_spec *specs;
7233 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
7234 * into arrays of btf_ids of struct fields and array indices.
7236 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
7241 struct bpf_cand_cache *cc;
7244 mutex_lock(&cand_cache_mutex);
7245 cc = bpf_core_find_cands(ctx, relo->type_id);
7247 bpf_log(ctx->log, "target candidate search failed for %d\n",
7253 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
7259 for (i = 0; i < cc->cnt; i++) {
7261 "CO-RE relocating %s %s: found target candidate [%d]\n",
7262 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
7263 cands.cands[i].btf = cc->cands[i].btf;
7264 cands.cands[i].id = cc->cands[i].id;
7266 cands.len = cc->cnt;
7267 /* cand_cache_mutex needs to span the cache lookup and
7268 * copy of btf pointer into bpf_core_cand_list,
7269 * since module can be unloaded while bpf_core_calc_relo_insn
7270 * is working with module's btf.
7274 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
7279 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
7286 mutex_unlock(&cand_cache_mutex);
7287 if (ctx->log->level & BPF_LOG_LEVEL2)
7288 print_cand_cache(ctx->log);