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 static s32 bpf_find_btf_id(const char *name, u32 kind, struct btf **btf_p)
534 btf = bpf_get_btf_vmlinux();
540 ret = btf_find_by_name_kind(btf, name, kind);
541 /* ret is never zero, since btf_find_by_name_kind returns
542 * positive btf_id or negative error.
550 /* If name is not found in vmlinux's BTF then search in module's BTFs */
551 spin_lock_bh(&btf_idr_lock);
552 idr_for_each_entry(&btf_idr, btf, id) {
553 if (!btf_is_module(btf))
555 /* linear search could be slow hence unlock/lock
556 * the IDR to avoiding holding it for too long
559 spin_unlock_bh(&btf_idr_lock);
560 ret = btf_find_by_name_kind(btf, name, kind);
565 spin_lock_bh(&btf_idr_lock);
568 spin_unlock_bh(&btf_idr_lock);
572 const struct btf_type *btf_type_skip_modifiers(const struct btf *btf,
575 const struct btf_type *t = btf_type_by_id(btf, id);
577 while (btf_type_is_modifier(t)) {
579 t = btf_type_by_id(btf, t->type);
588 const struct btf_type *btf_type_resolve_ptr(const struct btf *btf,
591 const struct btf_type *t;
593 t = btf_type_skip_modifiers(btf, id, NULL);
594 if (!btf_type_is_ptr(t))
597 return btf_type_skip_modifiers(btf, t->type, res_id);
600 const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf,
603 const struct btf_type *ptype;
605 ptype = btf_type_resolve_ptr(btf, id, res_id);
606 if (ptype && btf_type_is_func_proto(ptype))
612 /* Types that act only as a source, not sink or intermediate
613 * type when resolving.
615 static bool btf_type_is_resolve_source_only(const struct btf_type *t)
617 return btf_type_is_var(t) ||
618 btf_type_is_decl_tag(t) ||
619 btf_type_is_datasec(t);
622 /* What types need to be resolved?
624 * btf_type_is_modifier() is an obvious one.
626 * btf_type_is_struct() because its member refers to
627 * another type (through member->type).
629 * btf_type_is_var() because the variable refers to
630 * another type. btf_type_is_datasec() holds multiple
631 * btf_type_is_var() types that need resolving.
633 * btf_type_is_array() because its element (array->type)
634 * refers to another type. Array can be thought of a
635 * special case of struct while array just has the same
636 * member-type repeated by array->nelems of times.
638 static bool btf_type_needs_resolve(const struct btf_type *t)
640 return btf_type_is_modifier(t) ||
641 btf_type_is_ptr(t) ||
642 btf_type_is_struct(t) ||
643 btf_type_is_array(t) ||
644 btf_type_is_var(t) ||
645 btf_type_is_func(t) ||
646 btf_type_is_decl_tag(t) ||
647 btf_type_is_datasec(t);
650 /* t->size can be used */
651 static bool btf_type_has_size(const struct btf_type *t)
653 switch (BTF_INFO_KIND(t->info)) {
655 case BTF_KIND_STRUCT:
658 case BTF_KIND_DATASEC:
666 static const char *btf_int_encoding_str(u8 encoding)
670 else if (encoding == BTF_INT_SIGNED)
672 else if (encoding == BTF_INT_CHAR)
674 else if (encoding == BTF_INT_BOOL)
680 static u32 btf_type_int(const struct btf_type *t)
682 return *(u32 *)(t + 1);
685 static const struct btf_array *btf_type_array(const struct btf_type *t)
687 return (const struct btf_array *)(t + 1);
690 static const struct btf_enum *btf_type_enum(const struct btf_type *t)
692 return (const struct btf_enum *)(t + 1);
695 static const struct btf_var *btf_type_var(const struct btf_type *t)
697 return (const struct btf_var *)(t + 1);
700 static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t)
702 return (const struct btf_decl_tag *)(t + 1);
705 static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t)
707 return kind_ops[BTF_INFO_KIND(t->info)];
710 static bool btf_name_offset_valid(const struct btf *btf, u32 offset)
712 if (!BTF_STR_OFFSET_VALID(offset))
715 while (offset < btf->start_str_off)
718 offset -= btf->start_str_off;
719 return offset < btf->hdr.str_len;
722 static bool __btf_name_char_ok(char c, bool first, bool dot_ok)
724 if ((first ? !isalpha(c) :
727 ((c == '.' && !dot_ok) ||
733 static const char *btf_str_by_offset(const struct btf *btf, u32 offset)
735 while (offset < btf->start_str_off)
738 offset -= btf->start_str_off;
739 if (offset < btf->hdr.str_len)
740 return &btf->strings[offset];
745 static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok)
747 /* offset must be valid */
748 const char *src = btf_str_by_offset(btf, offset);
749 const char *src_limit;
751 if (!__btf_name_char_ok(*src, true, dot_ok))
754 /* set a limit on identifier length */
755 src_limit = src + KSYM_NAME_LEN;
757 while (*src && src < src_limit) {
758 if (!__btf_name_char_ok(*src, false, dot_ok))
766 /* Only C-style identifier is permitted. This can be relaxed if
769 static bool btf_name_valid_identifier(const struct btf *btf, u32 offset)
771 return __btf_name_valid(btf, offset, false);
774 static bool btf_name_valid_section(const struct btf *btf, u32 offset)
776 return __btf_name_valid(btf, offset, true);
779 static const char *__btf_name_by_offset(const struct btf *btf, u32 offset)
786 name = btf_str_by_offset(btf, offset);
787 return name ?: "(invalid-name-offset)";
790 const char *btf_name_by_offset(const struct btf *btf, u32 offset)
792 return btf_str_by_offset(btf, offset);
795 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id)
797 while (type_id < btf->start_id)
800 type_id -= btf->start_id;
801 if (type_id >= btf->nr_types)
803 return btf->types[type_id];
807 * Regular int is not a bit field and it must be either
808 * u8/u16/u32/u64 or __int128.
810 static bool btf_type_int_is_regular(const struct btf_type *t)
812 u8 nr_bits, nr_bytes;
815 int_data = btf_type_int(t);
816 nr_bits = BTF_INT_BITS(int_data);
817 nr_bytes = BITS_ROUNDUP_BYTES(nr_bits);
818 if (BITS_PER_BYTE_MASKED(nr_bits) ||
819 BTF_INT_OFFSET(int_data) ||
820 (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) &&
821 nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) &&
822 nr_bytes != (2 * sizeof(u64)))) {
830 * Check that given struct member is a regular int with expected
833 bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s,
834 const struct btf_member *m,
835 u32 expected_offset, u32 expected_size)
837 const struct btf_type *t;
842 t = btf_type_id_size(btf, &id, NULL);
843 if (!t || !btf_type_is_int(t))
846 int_data = btf_type_int(t);
847 nr_bits = BTF_INT_BITS(int_data);
848 if (btf_type_kflag(s)) {
849 u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset);
850 u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset);
852 /* if kflag set, int should be a regular int and
853 * bit offset should be at byte boundary.
855 return !bitfield_size &&
856 BITS_ROUNDUP_BYTES(bit_offset) == expected_offset &&
857 BITS_ROUNDUP_BYTES(nr_bits) == expected_size;
860 if (BTF_INT_OFFSET(int_data) ||
861 BITS_PER_BYTE_MASKED(m->offset) ||
862 BITS_ROUNDUP_BYTES(m->offset) != expected_offset ||
863 BITS_PER_BYTE_MASKED(nr_bits) ||
864 BITS_ROUNDUP_BYTES(nr_bits) != expected_size)
870 /* Similar to btf_type_skip_modifiers() but does not skip typedefs. */
871 static const struct btf_type *btf_type_skip_qualifiers(const struct btf *btf,
874 const struct btf_type *t = btf_type_by_id(btf, id);
876 while (btf_type_is_modifier(t) &&
877 BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) {
878 t = btf_type_by_id(btf, t->type);
884 #define BTF_SHOW_MAX_ITER 10
886 #define BTF_KIND_BIT(kind) (1ULL << kind)
889 * Populate show->state.name with type name information.
890 * Format of type name is
892 * [.member_name = ] (type_name)
894 static const char *btf_show_name(struct btf_show *show)
896 /* BTF_MAX_ITER array suffixes "[]" */
897 const char *array_suffixes = "[][][][][][][][][][]";
898 const char *array_suffix = &array_suffixes[strlen(array_suffixes)];
899 /* BTF_MAX_ITER pointer suffixes "*" */
900 const char *ptr_suffixes = "**********";
901 const char *ptr_suffix = &ptr_suffixes[strlen(ptr_suffixes)];
902 const char *name = NULL, *prefix = "", *parens = "";
903 const struct btf_member *m = show->state.member;
904 const struct btf_type *t;
905 const struct btf_array *array;
906 u32 id = show->state.type_id;
907 const char *member = NULL;
908 bool show_member = false;
912 show->state.name[0] = '\0';
915 * Don't show type name if we're showing an array member;
916 * in that case we show the array type so don't need to repeat
917 * ourselves for each member.
919 if (show->state.array_member)
922 /* Retrieve member name, if any. */
924 member = btf_name_by_offset(show->btf, m->name_off);
925 show_member = strlen(member) > 0;
930 * Start with type_id, as we have resolved the struct btf_type *
931 * via btf_modifier_show() past the parent typedef to the child
932 * struct, int etc it is defined as. In such cases, the type_id
933 * still represents the starting type while the struct btf_type *
934 * in our show->state points at the resolved type of the typedef.
936 t = btf_type_by_id(show->btf, id);
941 * The goal here is to build up the right number of pointer and
942 * array suffixes while ensuring the type name for a typedef
943 * is represented. Along the way we accumulate a list of
944 * BTF kinds we have encountered, since these will inform later
945 * display; for example, pointer types will not require an
946 * opening "{" for struct, we will just display the pointer value.
948 * We also want to accumulate the right number of pointer or array
949 * indices in the format string while iterating until we get to
950 * the typedef/pointee/array member target type.
952 * We start by pointing at the end of pointer and array suffix
953 * strings; as we accumulate pointers and arrays we move the pointer
954 * or array string backwards so it will show the expected number of
955 * '*' or '[]' for the type. BTF_SHOW_MAX_ITER of nesting of pointers
956 * and/or arrays and typedefs are supported as a precaution.
958 * We also want to get typedef name while proceeding to resolve
959 * type it points to so that we can add parentheses if it is a
960 * "typedef struct" etc.
962 for (i = 0; i < BTF_SHOW_MAX_ITER; i++) {
964 switch (BTF_INFO_KIND(t->info)) {
965 case BTF_KIND_TYPEDEF:
967 name = btf_name_by_offset(show->btf,
969 kinds |= BTF_KIND_BIT(BTF_KIND_TYPEDEF);
973 kinds |= BTF_KIND_BIT(BTF_KIND_ARRAY);
977 array = btf_type_array(t);
978 if (array_suffix > array_suffixes)
983 kinds |= BTF_KIND_BIT(BTF_KIND_PTR);
984 if (ptr_suffix > ptr_suffixes)
994 t = btf_type_skip_qualifiers(show->btf, id);
996 /* We may not be able to represent this type; bail to be safe */
997 if (i == BTF_SHOW_MAX_ITER)
1001 name = btf_name_by_offset(show->btf, t->name_off);
1003 switch (BTF_INFO_KIND(t->info)) {
1004 case BTF_KIND_STRUCT:
1005 case BTF_KIND_UNION:
1006 prefix = BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT ?
1008 /* if it's an array of struct/union, parens is already set */
1009 if (!(kinds & (BTF_KIND_BIT(BTF_KIND_ARRAY))))
1019 /* pointer does not require parens */
1020 if (kinds & BTF_KIND_BIT(BTF_KIND_PTR))
1022 /* typedef does not require struct/union/enum prefix */
1023 if (kinds & BTF_KIND_BIT(BTF_KIND_TYPEDEF))
1029 /* Even if we don't want type name info, we want parentheses etc */
1030 if (show->flags & BTF_SHOW_NONAME)
1031 snprintf(show->state.name, sizeof(show->state.name), "%s",
1034 snprintf(show->state.name, sizeof(show->state.name),
1035 "%s%s%s(%s%s%s%s%s%s)%s",
1036 /* first 3 strings comprise ".member = " */
1037 show_member ? "." : "",
1038 show_member ? member : "",
1039 show_member ? " = " : "",
1040 /* ...next is our prefix (struct, enum, etc) */
1042 strlen(prefix) > 0 && strlen(name) > 0 ? " " : "",
1043 /* ...this is the type name itself */
1045 /* ...suffixed by the appropriate '*', '[]' suffixes */
1046 strlen(ptr_suffix) > 0 ? " " : "", ptr_suffix,
1047 array_suffix, parens);
1049 return show->state.name;
1052 static const char *__btf_show_indent(struct btf_show *show)
1054 const char *indents = " ";
1055 const char *indent = &indents[strlen(indents)];
1057 if ((indent - show->state.depth) >= indents)
1058 return indent - show->state.depth;
1062 static const char *btf_show_indent(struct btf_show *show)
1064 return show->flags & BTF_SHOW_COMPACT ? "" : __btf_show_indent(show);
1067 static const char *btf_show_newline(struct btf_show *show)
1069 return show->flags & BTF_SHOW_COMPACT ? "" : "\n";
1072 static const char *btf_show_delim(struct btf_show *show)
1074 if (show->state.depth == 0)
1077 if ((show->flags & BTF_SHOW_COMPACT) && show->state.type &&
1078 BTF_INFO_KIND(show->state.type->info) == BTF_KIND_UNION)
1084 __printf(2, 3) static void btf_show(struct btf_show *show, const char *fmt, ...)
1088 if (!show->state.depth_check) {
1089 va_start(args, fmt);
1090 show->showfn(show, fmt, args);
1095 /* Macros are used here as btf_show_type_value[s]() prepends and appends
1096 * format specifiers to the format specifier passed in; these do the work of
1097 * adding indentation, delimiters etc while the caller simply has to specify
1098 * the type value(s) in the format specifier + value(s).
1100 #define btf_show_type_value(show, fmt, value) \
1102 if ((value) != 0 || (show->flags & BTF_SHOW_ZERO) || \
1103 show->state.depth == 0) { \
1104 btf_show(show, "%s%s" fmt "%s%s", \
1105 btf_show_indent(show), \
1106 btf_show_name(show), \
1107 value, btf_show_delim(show), \
1108 btf_show_newline(show)); \
1109 if (show->state.depth > show->state.depth_to_show) \
1110 show->state.depth_to_show = show->state.depth; \
1114 #define btf_show_type_values(show, fmt, ...) \
1116 btf_show(show, "%s%s" fmt "%s%s", btf_show_indent(show), \
1117 btf_show_name(show), \
1118 __VA_ARGS__, btf_show_delim(show), \
1119 btf_show_newline(show)); \
1120 if (show->state.depth > show->state.depth_to_show) \
1121 show->state.depth_to_show = show->state.depth; \
1124 /* How much is left to copy to safe buffer after @data? */
1125 static int btf_show_obj_size_left(struct btf_show *show, void *data)
1127 return show->obj.head + show->obj.size - data;
1130 /* Is object pointed to by @data of @size already copied to our safe buffer? */
1131 static bool btf_show_obj_is_safe(struct btf_show *show, void *data, int size)
1133 return data >= show->obj.data &&
1134 (data + size) < (show->obj.data + BTF_SHOW_OBJ_SAFE_SIZE);
1138 * If object pointed to by @data of @size falls within our safe buffer, return
1139 * the equivalent pointer to the same safe data. Assumes
1140 * copy_from_kernel_nofault() has already happened and our safe buffer is
1143 static void *__btf_show_obj_safe(struct btf_show *show, void *data, int size)
1145 if (btf_show_obj_is_safe(show, data, size))
1146 return show->obj.safe + (data - show->obj.data);
1151 * Return a safe-to-access version of data pointed to by @data.
1152 * We do this by copying the relevant amount of information
1153 * to the struct btf_show obj.safe buffer using copy_from_kernel_nofault().
1155 * If BTF_SHOW_UNSAFE is specified, just return data as-is; no
1156 * safe copy is needed.
1158 * Otherwise we need to determine if we have the required amount
1159 * of data (determined by the @data pointer and the size of the
1160 * largest base type we can encounter (represented by
1161 * BTF_SHOW_OBJ_BASE_TYPE_SIZE). Having that much data ensures
1162 * that we will be able to print some of the current object,
1163 * and if more is needed a copy will be triggered.
1164 * Some objects such as structs will not fit into the buffer;
1165 * in such cases additional copies when we iterate over their
1166 * members may be needed.
1168 * btf_show_obj_safe() is used to return a safe buffer for
1169 * btf_show_start_type(); this ensures that as we recurse into
1170 * nested types we always have safe data for the given type.
1171 * This approach is somewhat wasteful; it's possible for example
1172 * that when iterating over a large union we'll end up copying the
1173 * same data repeatedly, but the goal is safety not performance.
1174 * We use stack data as opposed to per-CPU buffers because the
1175 * iteration over a type can take some time, and preemption handling
1176 * would greatly complicate use of the safe buffer.
1178 static void *btf_show_obj_safe(struct btf_show *show,
1179 const struct btf_type *t,
1182 const struct btf_type *rt;
1183 int size_left, size;
1186 if (show->flags & BTF_SHOW_UNSAFE)
1189 rt = btf_resolve_size(show->btf, t, &size);
1191 show->state.status = PTR_ERR(rt);
1196 * Is this toplevel object? If so, set total object size and
1197 * initialize pointers. Otherwise check if we still fall within
1198 * our safe object data.
1200 if (show->state.depth == 0) {
1201 show->obj.size = size;
1202 show->obj.head = data;
1205 * If the size of the current object is > our remaining
1206 * safe buffer we _may_ need to do a new copy. However
1207 * consider the case of a nested struct; it's size pushes
1208 * us over the safe buffer limit, but showing any individual
1209 * struct members does not. In such cases, we don't need
1210 * to initiate a fresh copy yet; however we definitely need
1211 * at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes left
1212 * in our buffer, regardless of the current object size.
1213 * The logic here is that as we resolve types we will
1214 * hit a base type at some point, and we need to be sure
1215 * the next chunk of data is safely available to display
1216 * that type info safely. We cannot rely on the size of
1217 * the current object here because it may be much larger
1218 * than our current buffer (e.g. task_struct is 8k).
1219 * All we want to do here is ensure that we can print the
1220 * next basic type, which we can if either
1221 * - the current type size is within the safe buffer; or
1222 * - at least BTF_SHOW_OBJ_BASE_TYPE_SIZE bytes are left in
1225 safe = __btf_show_obj_safe(show, data,
1227 BTF_SHOW_OBJ_BASE_TYPE_SIZE));
1231 * We need a new copy to our safe object, either because we haven't
1232 * yet copied and are initializing safe data, or because the data
1233 * we want falls outside the boundaries of the safe object.
1236 size_left = btf_show_obj_size_left(show, data);
1237 if (size_left > BTF_SHOW_OBJ_SAFE_SIZE)
1238 size_left = BTF_SHOW_OBJ_SAFE_SIZE;
1239 show->state.status = copy_from_kernel_nofault(show->obj.safe,
1241 if (!show->state.status) {
1242 show->obj.data = data;
1243 safe = show->obj.safe;
1251 * Set the type we are starting to show and return a safe data pointer
1252 * to be used for showing the associated data.
1254 static void *btf_show_start_type(struct btf_show *show,
1255 const struct btf_type *t,
1256 u32 type_id, void *data)
1258 show->state.type = t;
1259 show->state.type_id = type_id;
1260 show->state.name[0] = '\0';
1262 return btf_show_obj_safe(show, t, data);
1265 static void btf_show_end_type(struct btf_show *show)
1267 show->state.type = NULL;
1268 show->state.type_id = 0;
1269 show->state.name[0] = '\0';
1272 static void *btf_show_start_aggr_type(struct btf_show *show,
1273 const struct btf_type *t,
1274 u32 type_id, void *data)
1276 void *safe_data = btf_show_start_type(show, t, type_id, data);
1281 btf_show(show, "%s%s%s", btf_show_indent(show),
1282 btf_show_name(show),
1283 btf_show_newline(show));
1284 show->state.depth++;
1288 static void btf_show_end_aggr_type(struct btf_show *show,
1291 show->state.depth--;
1292 btf_show(show, "%s%s%s%s", btf_show_indent(show), suffix,
1293 btf_show_delim(show), btf_show_newline(show));
1294 btf_show_end_type(show);
1297 static void btf_show_start_member(struct btf_show *show,
1298 const struct btf_member *m)
1300 show->state.member = m;
1303 static void btf_show_start_array_member(struct btf_show *show)
1305 show->state.array_member = 1;
1306 btf_show_start_member(show, NULL);
1309 static void btf_show_end_member(struct btf_show *show)
1311 show->state.member = NULL;
1314 static void btf_show_end_array_member(struct btf_show *show)
1316 show->state.array_member = 0;
1317 btf_show_end_member(show);
1320 static void *btf_show_start_array_type(struct btf_show *show,
1321 const struct btf_type *t,
1326 show->state.array_encoding = array_encoding;
1327 show->state.array_terminated = 0;
1328 return btf_show_start_aggr_type(show, t, type_id, data);
1331 static void btf_show_end_array_type(struct btf_show *show)
1333 show->state.array_encoding = 0;
1334 show->state.array_terminated = 0;
1335 btf_show_end_aggr_type(show, "]");
1338 static void *btf_show_start_struct_type(struct btf_show *show,
1339 const struct btf_type *t,
1343 return btf_show_start_aggr_type(show, t, type_id, data);
1346 static void btf_show_end_struct_type(struct btf_show *show)
1348 btf_show_end_aggr_type(show, "}");
1351 __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log,
1352 const char *fmt, ...)
1356 va_start(args, fmt);
1357 bpf_verifier_vlog(log, fmt, args);
1361 __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env,
1362 const char *fmt, ...)
1364 struct bpf_verifier_log *log = &env->log;
1367 if (!bpf_verifier_log_needed(log))
1370 va_start(args, fmt);
1371 bpf_verifier_vlog(log, fmt, args);
1375 __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env,
1376 const struct btf_type *t,
1378 const char *fmt, ...)
1380 struct bpf_verifier_log *log = &env->log;
1381 u8 kind = BTF_INFO_KIND(t->info);
1382 struct btf *btf = env->btf;
1385 if (!bpf_verifier_log_needed(log))
1388 /* btf verifier prints all types it is processing via
1389 * btf_verifier_log_type(..., fmt = NULL).
1390 * Skip those prints for in-kernel BTF verification.
1392 if (log->level == BPF_LOG_KERNEL && !fmt)
1395 __btf_verifier_log(log, "[%u] %s %s%s",
1398 __btf_name_by_offset(btf, t->name_off),
1399 log_details ? " " : "");
1402 btf_type_ops(t)->log_details(env, t);
1405 __btf_verifier_log(log, " ");
1406 va_start(args, fmt);
1407 bpf_verifier_vlog(log, fmt, args);
1411 __btf_verifier_log(log, "\n");
1414 #define btf_verifier_log_type(env, t, ...) \
1415 __btf_verifier_log_type((env), (t), true, __VA_ARGS__)
1416 #define btf_verifier_log_basic(env, t, ...) \
1417 __btf_verifier_log_type((env), (t), false, __VA_ARGS__)
1420 static void btf_verifier_log_member(struct btf_verifier_env *env,
1421 const struct btf_type *struct_type,
1422 const struct btf_member *member,
1423 const char *fmt, ...)
1425 struct bpf_verifier_log *log = &env->log;
1426 struct btf *btf = env->btf;
1429 if (!bpf_verifier_log_needed(log))
1432 if (log->level == BPF_LOG_KERNEL && !fmt)
1434 /* The CHECK_META phase already did a btf dump.
1436 * If member is logged again, it must hit an error in
1437 * parsing this member. It is useful to print out which
1438 * struct this member belongs to.
1440 if (env->phase != CHECK_META)
1441 btf_verifier_log_type(env, struct_type, NULL);
1443 if (btf_type_kflag(struct_type))
1444 __btf_verifier_log(log,
1445 "\t%s type_id=%u bitfield_size=%u bits_offset=%u",
1446 __btf_name_by_offset(btf, member->name_off),
1448 BTF_MEMBER_BITFIELD_SIZE(member->offset),
1449 BTF_MEMBER_BIT_OFFSET(member->offset));
1451 __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u",
1452 __btf_name_by_offset(btf, member->name_off),
1453 member->type, member->offset);
1456 __btf_verifier_log(log, " ");
1457 va_start(args, fmt);
1458 bpf_verifier_vlog(log, fmt, args);
1462 __btf_verifier_log(log, "\n");
1466 static void btf_verifier_log_vsi(struct btf_verifier_env *env,
1467 const struct btf_type *datasec_type,
1468 const struct btf_var_secinfo *vsi,
1469 const char *fmt, ...)
1471 struct bpf_verifier_log *log = &env->log;
1474 if (!bpf_verifier_log_needed(log))
1476 if (log->level == BPF_LOG_KERNEL && !fmt)
1478 if (env->phase != CHECK_META)
1479 btf_verifier_log_type(env, datasec_type, NULL);
1481 __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u",
1482 vsi->type, vsi->offset, vsi->size);
1484 __btf_verifier_log(log, " ");
1485 va_start(args, fmt);
1486 bpf_verifier_vlog(log, fmt, args);
1490 __btf_verifier_log(log, "\n");
1493 static void btf_verifier_log_hdr(struct btf_verifier_env *env,
1496 struct bpf_verifier_log *log = &env->log;
1497 const struct btf *btf = env->btf;
1498 const struct btf_header *hdr;
1500 if (!bpf_verifier_log_needed(log))
1503 if (log->level == BPF_LOG_KERNEL)
1506 __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic);
1507 __btf_verifier_log(log, "version: %u\n", hdr->version);
1508 __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags);
1509 __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len);
1510 __btf_verifier_log(log, "type_off: %u\n", hdr->type_off);
1511 __btf_verifier_log(log, "type_len: %u\n", hdr->type_len);
1512 __btf_verifier_log(log, "str_off: %u\n", hdr->str_off);
1513 __btf_verifier_log(log, "str_len: %u\n", hdr->str_len);
1514 __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size);
1517 static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t)
1519 struct btf *btf = env->btf;
1521 if (btf->types_size == btf->nr_types) {
1522 /* Expand 'types' array */
1524 struct btf_type **new_types;
1525 u32 expand_by, new_size;
1527 if (btf->start_id + btf->types_size == BTF_MAX_TYPE) {
1528 btf_verifier_log(env, "Exceeded max num of types");
1532 expand_by = max_t(u32, btf->types_size >> 2, 16);
1533 new_size = min_t(u32, BTF_MAX_TYPE,
1534 btf->types_size + expand_by);
1536 new_types = kvcalloc(new_size, sizeof(*new_types),
1537 GFP_KERNEL | __GFP_NOWARN);
1541 if (btf->nr_types == 0) {
1542 if (!btf->base_btf) {
1543 /* lazily init VOID type */
1544 new_types[0] = &btf_void;
1548 memcpy(new_types, btf->types,
1549 sizeof(*btf->types) * btf->nr_types);
1553 btf->types = new_types;
1554 btf->types_size = new_size;
1557 btf->types[btf->nr_types++] = t;
1562 static int btf_alloc_id(struct btf *btf)
1566 idr_preload(GFP_KERNEL);
1567 spin_lock_bh(&btf_idr_lock);
1568 id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC);
1571 spin_unlock_bh(&btf_idr_lock);
1574 if (WARN_ON_ONCE(!id))
1577 return id > 0 ? 0 : id;
1580 static void btf_free_id(struct btf *btf)
1582 unsigned long flags;
1585 * In map-in-map, calling map_delete_elem() on outer
1586 * map will call bpf_map_put on the inner map.
1587 * It will then eventually call btf_free_id()
1588 * on the inner map. Some of the map_delete_elem()
1589 * implementation may have irq disabled, so
1590 * we need to use the _irqsave() version instead
1591 * of the _bh() version.
1593 spin_lock_irqsave(&btf_idr_lock, flags);
1594 idr_remove(&btf_idr, btf->id);
1595 spin_unlock_irqrestore(&btf_idr_lock, flags);
1598 static void btf_free_kfunc_set_tab(struct btf *btf)
1600 struct btf_kfunc_set_tab *tab = btf->kfunc_set_tab;
1605 /* For module BTF, we directly assign the sets being registered, so
1606 * there is nothing to free except kfunc_set_tab.
1608 if (btf_is_module(btf))
1610 for (hook = 0; hook < ARRAY_SIZE(tab->sets); hook++) {
1611 for (type = 0; type < ARRAY_SIZE(tab->sets[0]); type++)
1612 kfree(tab->sets[hook][type]);
1616 btf->kfunc_set_tab = NULL;
1619 static void btf_free(struct btf *btf)
1621 btf_free_kfunc_set_tab(btf);
1623 kvfree(btf->resolved_sizes);
1624 kvfree(btf->resolved_ids);
1629 static void btf_free_rcu(struct rcu_head *rcu)
1631 struct btf *btf = container_of(rcu, struct btf, rcu);
1636 void btf_get(struct btf *btf)
1638 refcount_inc(&btf->refcnt);
1641 void btf_put(struct btf *btf)
1643 if (btf && refcount_dec_and_test(&btf->refcnt)) {
1645 call_rcu(&btf->rcu, btf_free_rcu);
1649 static int env_resolve_init(struct btf_verifier_env *env)
1651 struct btf *btf = env->btf;
1652 u32 nr_types = btf->nr_types;
1653 u32 *resolved_sizes = NULL;
1654 u32 *resolved_ids = NULL;
1655 u8 *visit_states = NULL;
1657 resolved_sizes = kvcalloc(nr_types, sizeof(*resolved_sizes),
1658 GFP_KERNEL | __GFP_NOWARN);
1659 if (!resolved_sizes)
1662 resolved_ids = kvcalloc(nr_types, sizeof(*resolved_ids),
1663 GFP_KERNEL | __GFP_NOWARN);
1667 visit_states = kvcalloc(nr_types, sizeof(*visit_states),
1668 GFP_KERNEL | __GFP_NOWARN);
1672 btf->resolved_sizes = resolved_sizes;
1673 btf->resolved_ids = resolved_ids;
1674 env->visit_states = visit_states;
1679 kvfree(resolved_sizes);
1680 kvfree(resolved_ids);
1681 kvfree(visit_states);
1685 static void btf_verifier_env_free(struct btf_verifier_env *env)
1687 kvfree(env->visit_states);
1691 static bool env_type_is_resolve_sink(const struct btf_verifier_env *env,
1692 const struct btf_type *next_type)
1694 switch (env->resolve_mode) {
1696 /* int, enum or void is a sink */
1697 return !btf_type_needs_resolve(next_type);
1699 /* int, enum, void, struct, array, func or func_proto is a sink
1702 return !btf_type_is_modifier(next_type) &&
1703 !btf_type_is_ptr(next_type);
1704 case RESOLVE_STRUCT_OR_ARRAY:
1705 /* int, enum, void, ptr, func or func_proto is a sink
1706 * for struct and array
1708 return !btf_type_is_modifier(next_type) &&
1709 !btf_type_is_array(next_type) &&
1710 !btf_type_is_struct(next_type);
1716 static bool env_type_is_resolved(const struct btf_verifier_env *env,
1719 /* base BTF types should be resolved by now */
1720 if (type_id < env->btf->start_id)
1723 return env->visit_states[type_id - env->btf->start_id] == RESOLVED;
1726 static int env_stack_push(struct btf_verifier_env *env,
1727 const struct btf_type *t, u32 type_id)
1729 const struct btf *btf = env->btf;
1730 struct resolve_vertex *v;
1732 if (env->top_stack == MAX_RESOLVE_DEPTH)
1735 if (type_id < btf->start_id
1736 || env->visit_states[type_id - btf->start_id] != NOT_VISITED)
1739 env->visit_states[type_id - btf->start_id] = VISITED;
1741 v = &env->stack[env->top_stack++];
1743 v->type_id = type_id;
1746 if (env->resolve_mode == RESOLVE_TBD) {
1747 if (btf_type_is_ptr(t))
1748 env->resolve_mode = RESOLVE_PTR;
1749 else if (btf_type_is_struct(t) || btf_type_is_array(t))
1750 env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY;
1756 static void env_stack_set_next_member(struct btf_verifier_env *env,
1759 env->stack[env->top_stack - 1].next_member = next_member;
1762 static void env_stack_pop_resolved(struct btf_verifier_env *env,
1763 u32 resolved_type_id,
1766 u32 type_id = env->stack[--(env->top_stack)].type_id;
1767 struct btf *btf = env->btf;
1769 type_id -= btf->start_id; /* adjust to local type id */
1770 btf->resolved_sizes[type_id] = resolved_size;
1771 btf->resolved_ids[type_id] = resolved_type_id;
1772 env->visit_states[type_id] = RESOLVED;
1775 static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env)
1777 return env->top_stack ? &env->stack[env->top_stack - 1] : NULL;
1780 /* Resolve the size of a passed-in "type"
1782 * type: is an array (e.g. u32 array[x][y])
1783 * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY,
1784 * *type_size: (x * y * sizeof(u32)). Hence, *type_size always
1785 * corresponds to the return type.
1787 * *elem_id: id of u32
1788 * *total_nelems: (x * y). Hence, individual elem size is
1789 * (*type_size / *total_nelems)
1790 * *type_id: id of type if it's changed within the function, 0 if not
1792 * type: is not an array (e.g. const struct X)
1793 * return type: type "struct X"
1794 * *type_size: sizeof(struct X)
1795 * *elem_type: same as return type ("struct X")
1798 * *type_id: id of type if it's changed within the function, 0 if not
1800 static const struct btf_type *
1801 __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1802 u32 *type_size, const struct btf_type **elem_type,
1803 u32 *elem_id, u32 *total_nelems, u32 *type_id)
1805 const struct btf_type *array_type = NULL;
1806 const struct btf_array *array = NULL;
1807 u32 i, size, nelems = 1, id = 0;
1809 for (i = 0; i < MAX_RESOLVE_DEPTH; i++) {
1810 switch (BTF_INFO_KIND(type->info)) {
1811 /* type->size can be used */
1813 case BTF_KIND_STRUCT:
1814 case BTF_KIND_UNION:
1816 case BTF_KIND_FLOAT:
1821 size = sizeof(void *);
1825 case BTF_KIND_TYPEDEF:
1826 case BTF_KIND_VOLATILE:
1827 case BTF_KIND_CONST:
1828 case BTF_KIND_RESTRICT:
1829 case BTF_KIND_TYPE_TAG:
1831 type = btf_type_by_id(btf, type->type);
1834 case BTF_KIND_ARRAY:
1837 array = btf_type_array(type);
1838 if (nelems && array->nelems > U32_MAX / nelems)
1839 return ERR_PTR(-EINVAL);
1840 nelems *= array->nelems;
1841 type = btf_type_by_id(btf, array->type);
1844 /* type without size */
1846 return ERR_PTR(-EINVAL);
1850 return ERR_PTR(-EINVAL);
1853 if (nelems && size > U32_MAX / nelems)
1854 return ERR_PTR(-EINVAL);
1856 *type_size = nelems * size;
1858 *total_nelems = nelems;
1862 *elem_id = array ? array->type : 0;
1866 return array_type ? : type;
1869 const struct btf_type *
1870 btf_resolve_size(const struct btf *btf, const struct btf_type *type,
1873 return __btf_resolve_size(btf, type, type_size, NULL, NULL, NULL, NULL);
1876 static u32 btf_resolved_type_id(const struct btf *btf, u32 type_id)
1878 while (type_id < btf->start_id)
1879 btf = btf->base_btf;
1881 return btf->resolved_ids[type_id - btf->start_id];
1884 /* The input param "type_id" must point to a needs_resolve type */
1885 static const struct btf_type *btf_type_id_resolve(const struct btf *btf,
1888 *type_id = btf_resolved_type_id(btf, *type_id);
1889 return btf_type_by_id(btf, *type_id);
1892 static u32 btf_resolved_type_size(const struct btf *btf, u32 type_id)
1894 while (type_id < btf->start_id)
1895 btf = btf->base_btf;
1897 return btf->resolved_sizes[type_id - btf->start_id];
1900 const struct btf_type *btf_type_id_size(const struct btf *btf,
1901 u32 *type_id, u32 *ret_size)
1903 const struct btf_type *size_type;
1904 u32 size_type_id = *type_id;
1907 size_type = btf_type_by_id(btf, size_type_id);
1908 if (btf_type_nosize_or_null(size_type))
1911 if (btf_type_has_size(size_type)) {
1912 size = size_type->size;
1913 } else if (btf_type_is_array(size_type)) {
1914 size = btf_resolved_type_size(btf, size_type_id);
1915 } else if (btf_type_is_ptr(size_type)) {
1916 size = sizeof(void *);
1918 if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) &&
1919 !btf_type_is_var(size_type)))
1922 size_type_id = btf_resolved_type_id(btf, size_type_id);
1923 size_type = btf_type_by_id(btf, size_type_id);
1924 if (btf_type_nosize_or_null(size_type))
1926 else if (btf_type_has_size(size_type))
1927 size = size_type->size;
1928 else if (btf_type_is_array(size_type))
1929 size = btf_resolved_type_size(btf, size_type_id);
1930 else if (btf_type_is_ptr(size_type))
1931 size = sizeof(void *);
1936 *type_id = size_type_id;
1943 static int btf_df_check_member(struct btf_verifier_env *env,
1944 const struct btf_type *struct_type,
1945 const struct btf_member *member,
1946 const struct btf_type *member_type)
1948 btf_verifier_log_basic(env, struct_type,
1949 "Unsupported check_member");
1953 static int btf_df_check_kflag_member(struct btf_verifier_env *env,
1954 const struct btf_type *struct_type,
1955 const struct btf_member *member,
1956 const struct btf_type *member_type)
1958 btf_verifier_log_basic(env, struct_type,
1959 "Unsupported check_kflag_member");
1963 /* Used for ptr, array struct/union and float type members.
1964 * int, enum and modifier types have their specific callback functions.
1966 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
1967 const struct btf_type *struct_type,
1968 const struct btf_member *member,
1969 const struct btf_type *member_type)
1971 if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) {
1972 btf_verifier_log_member(env, struct_type, member,
1973 "Invalid member bitfield_size");
1977 /* bitfield size is 0, so member->offset represents bit offset only.
1978 * It is safe to call non kflag check_member variants.
1980 return btf_type_ops(member_type)->check_member(env, struct_type,
1985 static int btf_df_resolve(struct btf_verifier_env *env,
1986 const struct resolve_vertex *v)
1988 btf_verifier_log_basic(env, v->t, "Unsupported resolve");
1992 static void btf_df_show(const struct btf *btf, const struct btf_type *t,
1993 u32 type_id, void *data, u8 bits_offsets,
1994 struct btf_show *show)
1996 btf_show(show, "<unsupported kind:%u>", BTF_INFO_KIND(t->info));
1999 static int btf_int_check_member(struct btf_verifier_env *env,
2000 const struct btf_type *struct_type,
2001 const struct btf_member *member,
2002 const struct btf_type *member_type)
2004 u32 int_data = btf_type_int(member_type);
2005 u32 struct_bits_off = member->offset;
2006 u32 struct_size = struct_type->size;
2010 if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) {
2011 btf_verifier_log_member(env, struct_type, member,
2012 "bits_offset exceeds U32_MAX");
2016 struct_bits_off += BTF_INT_OFFSET(int_data);
2017 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2018 nr_copy_bits = BTF_INT_BITS(int_data) +
2019 BITS_PER_BYTE_MASKED(struct_bits_off);
2021 if (nr_copy_bits > BITS_PER_U128) {
2022 btf_verifier_log_member(env, struct_type, member,
2023 "nr_copy_bits exceeds 128");
2027 if (struct_size < bytes_offset ||
2028 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2029 btf_verifier_log_member(env, struct_type, member,
2030 "Member exceeds struct_size");
2037 static int btf_int_check_kflag_member(struct btf_verifier_env *env,
2038 const struct btf_type *struct_type,
2039 const struct btf_member *member,
2040 const struct btf_type *member_type)
2042 u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset;
2043 u32 int_data = btf_type_int(member_type);
2044 u32 struct_size = struct_type->size;
2047 /* a regular int type is required for the kflag int member */
2048 if (!btf_type_int_is_regular(member_type)) {
2049 btf_verifier_log_member(env, struct_type, member,
2050 "Invalid member base type");
2054 /* check sanity of bitfield size */
2055 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
2056 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
2057 nr_int_data_bits = BTF_INT_BITS(int_data);
2059 /* Not a bitfield member, member offset must be at byte
2062 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2063 btf_verifier_log_member(env, struct_type, member,
2064 "Invalid member offset");
2068 nr_bits = nr_int_data_bits;
2069 } else if (nr_bits > nr_int_data_bits) {
2070 btf_verifier_log_member(env, struct_type, member,
2071 "Invalid member bitfield_size");
2075 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2076 nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off);
2077 if (nr_copy_bits > BITS_PER_U128) {
2078 btf_verifier_log_member(env, struct_type, member,
2079 "nr_copy_bits exceeds 128");
2083 if (struct_size < bytes_offset ||
2084 struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) {
2085 btf_verifier_log_member(env, struct_type, member,
2086 "Member exceeds struct_size");
2093 static s32 btf_int_check_meta(struct btf_verifier_env *env,
2094 const struct btf_type *t,
2097 u32 int_data, nr_bits, meta_needed = sizeof(int_data);
2100 if (meta_left < meta_needed) {
2101 btf_verifier_log_basic(env, t,
2102 "meta_left:%u meta_needed:%u",
2103 meta_left, meta_needed);
2107 if (btf_type_vlen(t)) {
2108 btf_verifier_log_type(env, t, "vlen != 0");
2112 if (btf_type_kflag(t)) {
2113 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2117 int_data = btf_type_int(t);
2118 if (int_data & ~BTF_INT_MASK) {
2119 btf_verifier_log_basic(env, t, "Invalid int_data:%x",
2124 nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data);
2126 if (nr_bits > BITS_PER_U128) {
2127 btf_verifier_log_type(env, t, "nr_bits exceeds %zu",
2132 if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) {
2133 btf_verifier_log_type(env, t, "nr_bits exceeds type_size");
2138 * Only one of the encoding bits is allowed and it
2139 * should be sufficient for the pretty print purpose (i.e. decoding).
2140 * Multiple bits can be allowed later if it is found
2141 * to be insufficient.
2143 encoding = BTF_INT_ENCODING(int_data);
2145 encoding != BTF_INT_SIGNED &&
2146 encoding != BTF_INT_CHAR &&
2147 encoding != BTF_INT_BOOL) {
2148 btf_verifier_log_type(env, t, "Unsupported encoding");
2152 btf_verifier_log_type(env, t, NULL);
2157 static void btf_int_log(struct btf_verifier_env *env,
2158 const struct btf_type *t)
2160 int int_data = btf_type_int(t);
2162 btf_verifier_log(env,
2163 "size=%u bits_offset=%u nr_bits=%u encoding=%s",
2164 t->size, BTF_INT_OFFSET(int_data),
2165 BTF_INT_BITS(int_data),
2166 btf_int_encoding_str(BTF_INT_ENCODING(int_data)));
2169 static void btf_int128_print(struct btf_show *show, void *data)
2171 /* data points to a __int128 number.
2173 * int128_num = *(__int128 *)data;
2174 * The below formulas shows what upper_num and lower_num represents:
2175 * upper_num = int128_num >> 64;
2176 * lower_num = int128_num & 0xffffffffFFFFFFFFULL;
2178 u64 upper_num, lower_num;
2180 #ifdef __BIG_ENDIAN_BITFIELD
2181 upper_num = *(u64 *)data;
2182 lower_num = *(u64 *)(data + 8);
2184 upper_num = *(u64 *)(data + 8);
2185 lower_num = *(u64 *)data;
2188 btf_show_type_value(show, "0x%llx", lower_num);
2190 btf_show_type_values(show, "0x%llx%016llx", upper_num,
2194 static void btf_int128_shift(u64 *print_num, u16 left_shift_bits,
2195 u16 right_shift_bits)
2197 u64 upper_num, lower_num;
2199 #ifdef __BIG_ENDIAN_BITFIELD
2200 upper_num = print_num[0];
2201 lower_num = print_num[1];
2203 upper_num = print_num[1];
2204 lower_num = print_num[0];
2207 /* shake out un-needed bits by shift/or operations */
2208 if (left_shift_bits >= 64) {
2209 upper_num = lower_num << (left_shift_bits - 64);
2212 upper_num = (upper_num << left_shift_bits) |
2213 (lower_num >> (64 - left_shift_bits));
2214 lower_num = lower_num << left_shift_bits;
2217 if (right_shift_bits >= 64) {
2218 lower_num = upper_num >> (right_shift_bits - 64);
2221 lower_num = (lower_num >> right_shift_bits) |
2222 (upper_num << (64 - right_shift_bits));
2223 upper_num = upper_num >> right_shift_bits;
2226 #ifdef __BIG_ENDIAN_BITFIELD
2227 print_num[0] = upper_num;
2228 print_num[1] = lower_num;
2230 print_num[0] = lower_num;
2231 print_num[1] = upper_num;
2235 static void btf_bitfield_show(void *data, u8 bits_offset,
2236 u8 nr_bits, struct btf_show *show)
2238 u16 left_shift_bits, right_shift_bits;
2241 u64 print_num[2] = {};
2243 nr_copy_bits = nr_bits + bits_offset;
2244 nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits);
2246 memcpy(print_num, data, nr_copy_bytes);
2248 #ifdef __BIG_ENDIAN_BITFIELD
2249 left_shift_bits = bits_offset;
2251 left_shift_bits = BITS_PER_U128 - nr_copy_bits;
2253 right_shift_bits = BITS_PER_U128 - nr_bits;
2255 btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
2256 btf_int128_print(show, print_num);
2260 static void btf_int_bits_show(const struct btf *btf,
2261 const struct btf_type *t,
2262 void *data, u8 bits_offset,
2263 struct btf_show *show)
2265 u32 int_data = btf_type_int(t);
2266 u8 nr_bits = BTF_INT_BITS(int_data);
2267 u8 total_bits_offset;
2270 * bits_offset is at most 7.
2271 * BTF_INT_OFFSET() cannot exceed 128 bits.
2273 total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data);
2274 data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
2275 bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
2276 btf_bitfield_show(data, bits_offset, nr_bits, show);
2279 static void btf_int_show(const struct btf *btf, const struct btf_type *t,
2280 u32 type_id, void *data, u8 bits_offset,
2281 struct btf_show *show)
2283 u32 int_data = btf_type_int(t);
2284 u8 encoding = BTF_INT_ENCODING(int_data);
2285 bool sign = encoding & BTF_INT_SIGNED;
2286 u8 nr_bits = BTF_INT_BITS(int_data);
2289 safe_data = btf_show_start_type(show, t, type_id, data);
2293 if (bits_offset || BTF_INT_OFFSET(int_data) ||
2294 BITS_PER_BYTE_MASKED(nr_bits)) {
2295 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2301 btf_int128_print(show, safe_data);
2305 btf_show_type_value(show, "%lld", *(s64 *)safe_data);
2307 btf_show_type_value(show, "%llu", *(u64 *)safe_data);
2311 btf_show_type_value(show, "%d", *(s32 *)safe_data);
2313 btf_show_type_value(show, "%u", *(u32 *)safe_data);
2317 btf_show_type_value(show, "%d", *(s16 *)safe_data);
2319 btf_show_type_value(show, "%u", *(u16 *)safe_data);
2322 if (show->state.array_encoding == BTF_INT_CHAR) {
2323 /* check for null terminator */
2324 if (show->state.array_terminated)
2326 if (*(char *)data == '\0') {
2327 show->state.array_terminated = 1;
2330 if (isprint(*(char *)data)) {
2331 btf_show_type_value(show, "'%c'",
2332 *(char *)safe_data);
2337 btf_show_type_value(show, "%d", *(s8 *)safe_data);
2339 btf_show_type_value(show, "%u", *(u8 *)safe_data);
2342 btf_int_bits_show(btf, t, safe_data, bits_offset, show);
2346 btf_show_end_type(show);
2349 static const struct btf_kind_operations int_ops = {
2350 .check_meta = btf_int_check_meta,
2351 .resolve = btf_df_resolve,
2352 .check_member = btf_int_check_member,
2353 .check_kflag_member = btf_int_check_kflag_member,
2354 .log_details = btf_int_log,
2355 .show = btf_int_show,
2358 static int btf_modifier_check_member(struct btf_verifier_env *env,
2359 const struct btf_type *struct_type,
2360 const struct btf_member *member,
2361 const struct btf_type *member_type)
2363 const struct btf_type *resolved_type;
2364 u32 resolved_type_id = member->type;
2365 struct btf_member resolved_member;
2366 struct btf *btf = env->btf;
2368 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2369 if (!resolved_type) {
2370 btf_verifier_log_member(env, struct_type, member,
2375 resolved_member = *member;
2376 resolved_member.type = resolved_type_id;
2378 return btf_type_ops(resolved_type)->check_member(env, struct_type,
2383 static int btf_modifier_check_kflag_member(struct btf_verifier_env *env,
2384 const struct btf_type *struct_type,
2385 const struct btf_member *member,
2386 const struct btf_type *member_type)
2388 const struct btf_type *resolved_type;
2389 u32 resolved_type_id = member->type;
2390 struct btf_member resolved_member;
2391 struct btf *btf = env->btf;
2393 resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL);
2394 if (!resolved_type) {
2395 btf_verifier_log_member(env, struct_type, member,
2400 resolved_member = *member;
2401 resolved_member.type = resolved_type_id;
2403 return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type,
2408 static int btf_ptr_check_member(struct btf_verifier_env *env,
2409 const struct btf_type *struct_type,
2410 const struct btf_member *member,
2411 const struct btf_type *member_type)
2413 u32 struct_size, struct_bits_off, bytes_offset;
2415 struct_size = struct_type->size;
2416 struct_bits_off = member->offset;
2417 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2419 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2420 btf_verifier_log_member(env, struct_type, member,
2421 "Member is not byte aligned");
2425 if (struct_size - bytes_offset < sizeof(void *)) {
2426 btf_verifier_log_member(env, struct_type, member,
2427 "Member exceeds struct_size");
2434 static int btf_ref_type_check_meta(struct btf_verifier_env *env,
2435 const struct btf_type *t,
2440 if (btf_type_vlen(t)) {
2441 btf_verifier_log_type(env, t, "vlen != 0");
2445 if (btf_type_kflag(t)) {
2446 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2450 if (!BTF_TYPE_ID_VALID(t->type)) {
2451 btf_verifier_log_type(env, t, "Invalid type_id");
2455 /* typedef/type_tag type must have a valid name, and other ref types,
2456 * volatile, const, restrict, should have a null name.
2458 if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) {
2460 !btf_name_valid_identifier(env->btf, t->name_off)) {
2461 btf_verifier_log_type(env, t, "Invalid name");
2464 } else if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPE_TAG) {
2465 value = btf_name_by_offset(env->btf, t->name_off);
2466 if (!value || !value[0]) {
2467 btf_verifier_log_type(env, t, "Invalid name");
2472 btf_verifier_log_type(env, t, "Invalid name");
2477 btf_verifier_log_type(env, t, NULL);
2482 static int btf_modifier_resolve(struct btf_verifier_env *env,
2483 const struct resolve_vertex *v)
2485 const struct btf_type *t = v->t;
2486 const struct btf_type *next_type;
2487 u32 next_type_id = t->type;
2488 struct btf *btf = env->btf;
2490 next_type = btf_type_by_id(btf, next_type_id);
2491 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2492 btf_verifier_log_type(env, v->t, "Invalid type_id");
2496 if (!env_type_is_resolve_sink(env, next_type) &&
2497 !env_type_is_resolved(env, next_type_id))
2498 return env_stack_push(env, next_type, next_type_id);
2500 /* Figure out the resolved next_type_id with size.
2501 * They will be stored in the current modifier's
2502 * resolved_ids and resolved_sizes such that it can
2503 * save us a few type-following when we use it later (e.g. in
2506 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2507 if (env_type_is_resolved(env, next_type_id))
2508 next_type = btf_type_id_resolve(btf, &next_type_id);
2510 /* "typedef void new_void", "const void"...etc */
2511 if (!btf_type_is_void(next_type) &&
2512 !btf_type_is_fwd(next_type) &&
2513 !btf_type_is_func_proto(next_type)) {
2514 btf_verifier_log_type(env, v->t, "Invalid type_id");
2519 env_stack_pop_resolved(env, next_type_id, 0);
2524 static int btf_var_resolve(struct btf_verifier_env *env,
2525 const struct resolve_vertex *v)
2527 const struct btf_type *next_type;
2528 const struct btf_type *t = v->t;
2529 u32 next_type_id = t->type;
2530 struct btf *btf = env->btf;
2532 next_type = btf_type_by_id(btf, next_type_id);
2533 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2534 btf_verifier_log_type(env, v->t, "Invalid type_id");
2538 if (!env_type_is_resolve_sink(env, next_type) &&
2539 !env_type_is_resolved(env, next_type_id))
2540 return env_stack_push(env, next_type, next_type_id);
2542 if (btf_type_is_modifier(next_type)) {
2543 const struct btf_type *resolved_type;
2544 u32 resolved_type_id;
2546 resolved_type_id = next_type_id;
2547 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2549 if (btf_type_is_ptr(resolved_type) &&
2550 !env_type_is_resolve_sink(env, resolved_type) &&
2551 !env_type_is_resolved(env, resolved_type_id))
2552 return env_stack_push(env, resolved_type,
2556 /* We must resolve to something concrete at this point, no
2557 * forward types or similar that would resolve to size of
2560 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2561 btf_verifier_log_type(env, v->t, "Invalid type_id");
2565 env_stack_pop_resolved(env, next_type_id, 0);
2570 static int btf_ptr_resolve(struct btf_verifier_env *env,
2571 const struct resolve_vertex *v)
2573 const struct btf_type *next_type;
2574 const struct btf_type *t = v->t;
2575 u32 next_type_id = t->type;
2576 struct btf *btf = env->btf;
2578 next_type = btf_type_by_id(btf, next_type_id);
2579 if (!next_type || btf_type_is_resolve_source_only(next_type)) {
2580 btf_verifier_log_type(env, v->t, "Invalid type_id");
2584 if (!env_type_is_resolve_sink(env, next_type) &&
2585 !env_type_is_resolved(env, next_type_id))
2586 return env_stack_push(env, next_type, next_type_id);
2588 /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY,
2589 * the modifier may have stopped resolving when it was resolved
2590 * to a ptr (last-resolved-ptr).
2592 * We now need to continue from the last-resolved-ptr to
2593 * ensure the last-resolved-ptr will not referring back to
2594 * the current ptr (t).
2596 if (btf_type_is_modifier(next_type)) {
2597 const struct btf_type *resolved_type;
2598 u32 resolved_type_id;
2600 resolved_type_id = next_type_id;
2601 resolved_type = btf_type_id_resolve(btf, &resolved_type_id);
2603 if (btf_type_is_ptr(resolved_type) &&
2604 !env_type_is_resolve_sink(env, resolved_type) &&
2605 !env_type_is_resolved(env, resolved_type_id))
2606 return env_stack_push(env, resolved_type,
2610 if (!btf_type_id_size(btf, &next_type_id, NULL)) {
2611 if (env_type_is_resolved(env, next_type_id))
2612 next_type = btf_type_id_resolve(btf, &next_type_id);
2614 if (!btf_type_is_void(next_type) &&
2615 !btf_type_is_fwd(next_type) &&
2616 !btf_type_is_func_proto(next_type)) {
2617 btf_verifier_log_type(env, v->t, "Invalid type_id");
2622 env_stack_pop_resolved(env, next_type_id, 0);
2627 static void btf_modifier_show(const struct btf *btf,
2628 const struct btf_type *t,
2629 u32 type_id, void *data,
2630 u8 bits_offset, struct btf_show *show)
2632 if (btf->resolved_ids)
2633 t = btf_type_id_resolve(btf, &type_id);
2635 t = btf_type_skip_modifiers(btf, type_id, NULL);
2637 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2640 static void btf_var_show(const struct btf *btf, const struct btf_type *t,
2641 u32 type_id, void *data, u8 bits_offset,
2642 struct btf_show *show)
2644 t = btf_type_id_resolve(btf, &type_id);
2646 btf_type_ops(t)->show(btf, t, type_id, data, bits_offset, show);
2649 static void btf_ptr_show(const struct btf *btf, const struct btf_type *t,
2650 u32 type_id, void *data, u8 bits_offset,
2651 struct btf_show *show)
2655 safe_data = btf_show_start_type(show, t, type_id, data);
2659 /* It is a hashed value unless BTF_SHOW_PTR_RAW is specified */
2660 if (show->flags & BTF_SHOW_PTR_RAW)
2661 btf_show_type_value(show, "0x%px", *(void **)safe_data);
2663 btf_show_type_value(show, "0x%p", *(void **)safe_data);
2664 btf_show_end_type(show);
2667 static void btf_ref_type_log(struct btf_verifier_env *env,
2668 const struct btf_type *t)
2670 btf_verifier_log(env, "type_id=%u", t->type);
2673 static struct btf_kind_operations modifier_ops = {
2674 .check_meta = btf_ref_type_check_meta,
2675 .resolve = btf_modifier_resolve,
2676 .check_member = btf_modifier_check_member,
2677 .check_kflag_member = btf_modifier_check_kflag_member,
2678 .log_details = btf_ref_type_log,
2679 .show = btf_modifier_show,
2682 static struct btf_kind_operations ptr_ops = {
2683 .check_meta = btf_ref_type_check_meta,
2684 .resolve = btf_ptr_resolve,
2685 .check_member = btf_ptr_check_member,
2686 .check_kflag_member = btf_generic_check_kflag_member,
2687 .log_details = btf_ref_type_log,
2688 .show = btf_ptr_show,
2691 static s32 btf_fwd_check_meta(struct btf_verifier_env *env,
2692 const struct btf_type *t,
2695 if (btf_type_vlen(t)) {
2696 btf_verifier_log_type(env, t, "vlen != 0");
2701 btf_verifier_log_type(env, t, "type != 0");
2705 /* fwd type must have a valid name */
2707 !btf_name_valid_identifier(env->btf, t->name_off)) {
2708 btf_verifier_log_type(env, t, "Invalid name");
2712 btf_verifier_log_type(env, t, NULL);
2717 static void btf_fwd_type_log(struct btf_verifier_env *env,
2718 const struct btf_type *t)
2720 btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct");
2723 static struct btf_kind_operations fwd_ops = {
2724 .check_meta = btf_fwd_check_meta,
2725 .resolve = btf_df_resolve,
2726 .check_member = btf_df_check_member,
2727 .check_kflag_member = btf_df_check_kflag_member,
2728 .log_details = btf_fwd_type_log,
2729 .show = btf_df_show,
2732 static int btf_array_check_member(struct btf_verifier_env *env,
2733 const struct btf_type *struct_type,
2734 const struct btf_member *member,
2735 const struct btf_type *member_type)
2737 u32 struct_bits_off = member->offset;
2738 u32 struct_size, bytes_offset;
2739 u32 array_type_id, array_size;
2740 struct btf *btf = env->btf;
2742 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2743 btf_verifier_log_member(env, struct_type, member,
2744 "Member is not byte aligned");
2748 array_type_id = member->type;
2749 btf_type_id_size(btf, &array_type_id, &array_size);
2750 struct_size = struct_type->size;
2751 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2752 if (struct_size - bytes_offset < array_size) {
2753 btf_verifier_log_member(env, struct_type, member,
2754 "Member exceeds struct_size");
2761 static s32 btf_array_check_meta(struct btf_verifier_env *env,
2762 const struct btf_type *t,
2765 const struct btf_array *array = btf_type_array(t);
2766 u32 meta_needed = sizeof(*array);
2768 if (meta_left < meta_needed) {
2769 btf_verifier_log_basic(env, t,
2770 "meta_left:%u meta_needed:%u",
2771 meta_left, meta_needed);
2775 /* array type should not have a name */
2777 btf_verifier_log_type(env, t, "Invalid name");
2781 if (btf_type_vlen(t)) {
2782 btf_verifier_log_type(env, t, "vlen != 0");
2786 if (btf_type_kflag(t)) {
2787 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
2792 btf_verifier_log_type(env, t, "size != 0");
2796 /* Array elem type and index type cannot be in type void,
2797 * so !array->type and !array->index_type are not allowed.
2799 if (!array->type || !BTF_TYPE_ID_VALID(array->type)) {
2800 btf_verifier_log_type(env, t, "Invalid elem");
2804 if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) {
2805 btf_verifier_log_type(env, t, "Invalid index");
2809 btf_verifier_log_type(env, t, NULL);
2814 static int btf_array_resolve(struct btf_verifier_env *env,
2815 const struct resolve_vertex *v)
2817 const struct btf_array *array = btf_type_array(v->t);
2818 const struct btf_type *elem_type, *index_type;
2819 u32 elem_type_id, index_type_id;
2820 struct btf *btf = env->btf;
2823 /* Check array->index_type */
2824 index_type_id = array->index_type;
2825 index_type = btf_type_by_id(btf, index_type_id);
2826 if (btf_type_nosize_or_null(index_type) ||
2827 btf_type_is_resolve_source_only(index_type)) {
2828 btf_verifier_log_type(env, v->t, "Invalid index");
2832 if (!env_type_is_resolve_sink(env, index_type) &&
2833 !env_type_is_resolved(env, index_type_id))
2834 return env_stack_push(env, index_type, index_type_id);
2836 index_type = btf_type_id_size(btf, &index_type_id, NULL);
2837 if (!index_type || !btf_type_is_int(index_type) ||
2838 !btf_type_int_is_regular(index_type)) {
2839 btf_verifier_log_type(env, v->t, "Invalid index");
2843 /* Check array->type */
2844 elem_type_id = array->type;
2845 elem_type = btf_type_by_id(btf, elem_type_id);
2846 if (btf_type_nosize_or_null(elem_type) ||
2847 btf_type_is_resolve_source_only(elem_type)) {
2848 btf_verifier_log_type(env, v->t,
2853 if (!env_type_is_resolve_sink(env, elem_type) &&
2854 !env_type_is_resolved(env, elem_type_id))
2855 return env_stack_push(env, elem_type, elem_type_id);
2857 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
2859 btf_verifier_log_type(env, v->t, "Invalid elem");
2863 if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) {
2864 btf_verifier_log_type(env, v->t, "Invalid array of int");
2868 if (array->nelems && elem_size > U32_MAX / array->nelems) {
2869 btf_verifier_log_type(env, v->t,
2870 "Array size overflows U32_MAX");
2874 env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems);
2879 static void btf_array_log(struct btf_verifier_env *env,
2880 const struct btf_type *t)
2882 const struct btf_array *array = btf_type_array(t);
2884 btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u",
2885 array->type, array->index_type, array->nelems);
2888 static void __btf_array_show(const struct btf *btf, const struct btf_type *t,
2889 u32 type_id, void *data, u8 bits_offset,
2890 struct btf_show *show)
2892 const struct btf_array *array = btf_type_array(t);
2893 const struct btf_kind_operations *elem_ops;
2894 const struct btf_type *elem_type;
2895 u32 i, elem_size = 0, elem_type_id;
2898 elem_type_id = array->type;
2899 elem_type = btf_type_skip_modifiers(btf, elem_type_id, NULL);
2900 if (elem_type && btf_type_has_size(elem_type))
2901 elem_size = elem_type->size;
2903 if (elem_type && btf_type_is_int(elem_type)) {
2904 u32 int_type = btf_type_int(elem_type);
2906 encoding = BTF_INT_ENCODING(int_type);
2909 * BTF_INT_CHAR encoding never seems to be set for
2910 * char arrays, so if size is 1 and element is
2911 * printable as a char, we'll do that.
2914 encoding = BTF_INT_CHAR;
2917 if (!btf_show_start_array_type(show, t, type_id, encoding, data))
2922 elem_ops = btf_type_ops(elem_type);
2924 for (i = 0; i < array->nelems; i++) {
2926 btf_show_start_array_member(show);
2928 elem_ops->show(btf, elem_type, elem_type_id, data,
2932 btf_show_end_array_member(show);
2934 if (show->state.array_terminated)
2938 btf_show_end_array_type(show);
2941 static void btf_array_show(const struct btf *btf, const struct btf_type *t,
2942 u32 type_id, void *data, u8 bits_offset,
2943 struct btf_show *show)
2945 const struct btf_member *m = show->state.member;
2948 * First check if any members would be shown (are non-zero).
2949 * See comments above "struct btf_show" definition for more
2950 * details on how this works at a high-level.
2952 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
2953 if (!show->state.depth_check) {
2954 show->state.depth_check = show->state.depth + 1;
2955 show->state.depth_to_show = 0;
2957 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2958 show->state.member = m;
2960 if (show->state.depth_check != show->state.depth + 1)
2962 show->state.depth_check = 0;
2964 if (show->state.depth_to_show <= show->state.depth)
2967 * Reaching here indicates we have recursed and found
2968 * non-zero array member(s).
2971 __btf_array_show(btf, t, type_id, data, bits_offset, show);
2974 static struct btf_kind_operations array_ops = {
2975 .check_meta = btf_array_check_meta,
2976 .resolve = btf_array_resolve,
2977 .check_member = btf_array_check_member,
2978 .check_kflag_member = btf_generic_check_kflag_member,
2979 .log_details = btf_array_log,
2980 .show = btf_array_show,
2983 static int btf_struct_check_member(struct btf_verifier_env *env,
2984 const struct btf_type *struct_type,
2985 const struct btf_member *member,
2986 const struct btf_type *member_type)
2988 u32 struct_bits_off = member->offset;
2989 u32 struct_size, bytes_offset;
2991 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
2992 btf_verifier_log_member(env, struct_type, member,
2993 "Member is not byte aligned");
2997 struct_size = struct_type->size;
2998 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
2999 if (struct_size - bytes_offset < member_type->size) {
3000 btf_verifier_log_member(env, struct_type, member,
3001 "Member exceeds struct_size");
3008 static s32 btf_struct_check_meta(struct btf_verifier_env *env,
3009 const struct btf_type *t,
3012 bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION;
3013 const struct btf_member *member;
3014 u32 meta_needed, last_offset;
3015 struct btf *btf = env->btf;
3016 u32 struct_size = t->size;
3020 meta_needed = btf_type_vlen(t) * sizeof(*member);
3021 if (meta_left < meta_needed) {
3022 btf_verifier_log_basic(env, t,
3023 "meta_left:%u meta_needed:%u",
3024 meta_left, meta_needed);
3028 /* struct type either no name or a valid one */
3030 !btf_name_valid_identifier(env->btf, t->name_off)) {
3031 btf_verifier_log_type(env, t, "Invalid name");
3035 btf_verifier_log_type(env, t, NULL);
3038 for_each_member(i, t, member) {
3039 if (!btf_name_offset_valid(btf, member->name_off)) {
3040 btf_verifier_log_member(env, t, member,
3041 "Invalid member name_offset:%u",
3046 /* struct member either no name or a valid one */
3047 if (member->name_off &&
3048 !btf_name_valid_identifier(btf, member->name_off)) {
3049 btf_verifier_log_member(env, t, member, "Invalid name");
3052 /* A member cannot be in type void */
3053 if (!member->type || !BTF_TYPE_ID_VALID(member->type)) {
3054 btf_verifier_log_member(env, t, member,
3059 offset = __btf_member_bit_offset(t, member);
3060 if (is_union && offset) {
3061 btf_verifier_log_member(env, t, member,
3062 "Invalid member bits_offset");
3067 * ">" instead of ">=" because the last member could be
3070 if (last_offset > offset) {
3071 btf_verifier_log_member(env, t, member,
3072 "Invalid member bits_offset");
3076 if (BITS_ROUNDUP_BYTES(offset) > struct_size) {
3077 btf_verifier_log_member(env, t, member,
3078 "Member bits_offset exceeds its struct size");
3082 btf_verifier_log_member(env, t, member, NULL);
3083 last_offset = offset;
3089 static int btf_struct_resolve(struct btf_verifier_env *env,
3090 const struct resolve_vertex *v)
3092 const struct btf_member *member;
3096 /* Before continue resolving the next_member,
3097 * ensure the last member is indeed resolved to a
3098 * type with size info.
3100 if (v->next_member) {
3101 const struct btf_type *last_member_type;
3102 const struct btf_member *last_member;
3103 u16 last_member_type_id;
3105 last_member = btf_type_member(v->t) + v->next_member - 1;
3106 last_member_type_id = last_member->type;
3107 if (WARN_ON_ONCE(!env_type_is_resolved(env,
3108 last_member_type_id)))
3111 last_member_type = btf_type_by_id(env->btf,
3112 last_member_type_id);
3113 if (btf_type_kflag(v->t))
3114 err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t,
3118 err = btf_type_ops(last_member_type)->check_member(env, v->t,
3125 for_each_member_from(i, v->next_member, v->t, member) {
3126 u32 member_type_id = member->type;
3127 const struct btf_type *member_type = btf_type_by_id(env->btf,
3130 if (btf_type_nosize_or_null(member_type) ||
3131 btf_type_is_resolve_source_only(member_type)) {
3132 btf_verifier_log_member(env, v->t, member,
3137 if (!env_type_is_resolve_sink(env, member_type) &&
3138 !env_type_is_resolved(env, member_type_id)) {
3139 env_stack_set_next_member(env, i + 1);
3140 return env_stack_push(env, member_type, member_type_id);
3143 if (btf_type_kflag(v->t))
3144 err = btf_type_ops(member_type)->check_kflag_member(env, v->t,
3148 err = btf_type_ops(member_type)->check_member(env, v->t,
3155 env_stack_pop_resolved(env, 0, 0);
3160 static void btf_struct_log(struct btf_verifier_env *env,
3161 const struct btf_type *t)
3163 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3166 enum btf_field_type {
3167 BTF_FIELD_SPIN_LOCK,
3173 BTF_FIELD_IGNORE = 0,
3174 BTF_FIELD_FOUND = 1,
3177 struct btf_field_info {
3182 static int btf_find_struct(const struct btf *btf, const struct btf_type *t,
3183 u32 off, int sz, struct btf_field_info *info)
3185 if (!__btf_type_is_struct(t))
3186 return BTF_FIELD_IGNORE;
3188 return BTF_FIELD_IGNORE;
3190 return BTF_FIELD_FOUND;
3193 static int btf_find_kptr(const struct btf *btf, const struct btf_type *t,
3194 u32 off, int sz, struct btf_field_info *info)
3198 /* For PTR, sz is always == 8 */
3199 if (!btf_type_is_ptr(t))
3200 return BTF_FIELD_IGNORE;
3201 t = btf_type_by_id(btf, t->type);
3203 if (!btf_type_is_type_tag(t))
3204 return BTF_FIELD_IGNORE;
3205 /* Reject extra tags */
3206 if (btf_type_is_type_tag(btf_type_by_id(btf, t->type)))
3208 if (strcmp("kptr", __btf_name_by_offset(btf, t->name_off)))
3211 /* Get the base type */
3212 t = btf_type_skip_modifiers(btf, t->type, &res_id);
3213 /* Only pointer to struct is allowed */
3214 if (!__btf_type_is_struct(t))
3217 info->type_id = res_id;
3219 return BTF_FIELD_FOUND;
3222 static int btf_find_struct_field(const struct btf *btf, const struct btf_type *t,
3223 const char *name, int sz, int align,
3224 enum btf_field_type field_type,
3225 struct btf_field_info *info, int info_cnt)
3227 const struct btf_member *member;
3228 struct btf_field_info tmp;
3232 for_each_member(i, t, member) {
3233 const struct btf_type *member_type = btf_type_by_id(btf,
3236 if (name && strcmp(__btf_name_by_offset(btf, member_type->name_off), name))
3239 off = __btf_member_bit_offset(t, member);
3241 /* valid C code cannot generate such BTF */
3247 switch (field_type) {
3248 case BTF_FIELD_SPIN_LOCK:
3249 case BTF_FIELD_TIMER:
3250 ret = btf_find_struct(btf, member_type, off, sz,
3251 idx < info_cnt ? &info[idx] : &tmp);
3255 case BTF_FIELD_KPTR:
3256 ret = btf_find_kptr(btf, member_type, off, sz,
3257 idx < info_cnt ? &info[idx] : &tmp);
3265 if (ret == BTF_FIELD_IGNORE)
3267 if (idx >= info_cnt)
3274 static int btf_find_datasec_var(const struct btf *btf, const struct btf_type *t,
3275 const char *name, int sz, int align,
3276 enum btf_field_type field_type,
3277 struct btf_field_info *info, int info_cnt)
3279 const struct btf_var_secinfo *vsi;
3280 struct btf_field_info tmp;
3284 for_each_vsi(i, t, vsi) {
3285 const struct btf_type *var = btf_type_by_id(btf, vsi->type);
3286 const struct btf_type *var_type = btf_type_by_id(btf, var->type);
3290 if (name && strcmp(__btf_name_by_offset(btf, var_type->name_off), name))
3292 if (vsi->size != sz)
3297 switch (field_type) {
3298 case BTF_FIELD_SPIN_LOCK:
3299 case BTF_FIELD_TIMER:
3300 ret = btf_find_struct(btf, var_type, off, sz,
3301 idx < info_cnt ? &info[idx] : &tmp);
3305 case BTF_FIELD_KPTR:
3306 ret = btf_find_kptr(btf, var_type, off, sz,
3307 idx < info_cnt ? &info[idx] : &tmp);
3315 if (ret == BTF_FIELD_IGNORE)
3317 if (idx >= info_cnt)
3324 static int btf_find_field(const struct btf *btf, const struct btf_type *t,
3325 enum btf_field_type field_type,
3326 struct btf_field_info *info, int info_cnt)
3331 switch (field_type) {
3332 case BTF_FIELD_SPIN_LOCK:
3333 name = "bpf_spin_lock";
3334 sz = sizeof(struct bpf_spin_lock);
3335 align = __alignof__(struct bpf_spin_lock);
3337 case BTF_FIELD_TIMER:
3339 sz = sizeof(struct bpf_timer);
3340 align = __alignof__(struct bpf_timer);
3342 case BTF_FIELD_KPTR:
3351 if (__btf_type_is_struct(t))
3352 return btf_find_struct_field(btf, t, name, sz, align, field_type, info, info_cnt);
3353 else if (btf_type_is_datasec(t))
3354 return btf_find_datasec_var(btf, t, name, sz, align, field_type, info, info_cnt);
3358 /* find 'struct bpf_spin_lock' in map value.
3359 * return >= 0 offset if found
3360 * and < 0 in case of error
3362 int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t)
3364 struct btf_field_info info;
3367 ret = btf_find_field(btf, t, BTF_FIELD_SPIN_LOCK, &info, 1);
3375 int btf_find_timer(const struct btf *btf, const struct btf_type *t)
3377 struct btf_field_info info;
3380 ret = btf_find_field(btf, t, BTF_FIELD_TIMER, &info, 1);
3388 struct bpf_map_value_off *btf_parse_kptrs(const struct btf *btf,
3389 const struct btf_type *t)
3391 struct btf_field_info info_arr[BPF_MAP_VALUE_OFF_MAX];
3392 struct bpf_map_value_off *tab;
3393 struct btf *kernel_btf = NULL;
3396 ret = btf_find_field(btf, t, BTF_FIELD_KPTR, info_arr, ARRAY_SIZE(info_arr));
3398 return ERR_PTR(ret);
3403 tab = kzalloc(offsetof(struct bpf_map_value_off, off[nr_off]), GFP_KERNEL | __GFP_NOWARN);
3405 return ERR_PTR(-ENOMEM);
3407 for (i = 0; i < nr_off; i++) {
3408 const struct btf_type *t;
3411 /* Find type in map BTF, and use it to look up the matching type
3412 * in vmlinux or module BTFs, by name and kind.
3414 t = btf_type_by_id(btf, info_arr[i].type_id);
3415 id = bpf_find_btf_id(__btf_name_by_offset(btf, t->name_off), BTF_INFO_KIND(t->info),
3422 tab->off[i].offset = info_arr[i].off;
3423 tab->off[i].kptr.btf_id = id;
3424 tab->off[i].kptr.btf = kernel_btf;
3426 tab->nr_off = nr_off;
3430 btf_put(tab->off[i].kptr.btf);
3432 return ERR_PTR(ret);
3435 static void __btf_struct_show(const struct btf *btf, const struct btf_type *t,
3436 u32 type_id, void *data, u8 bits_offset,
3437 struct btf_show *show)
3439 const struct btf_member *member;
3443 safe_data = btf_show_start_struct_type(show, t, type_id, data);
3447 for_each_member(i, t, member) {
3448 const struct btf_type *member_type = btf_type_by_id(btf,
3450 const struct btf_kind_operations *ops;
3451 u32 member_offset, bitfield_size;
3455 btf_show_start_member(show, member);
3457 member_offset = __btf_member_bit_offset(t, member);
3458 bitfield_size = __btf_member_bitfield_size(t, member);
3459 bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset);
3460 bits8_offset = BITS_PER_BYTE_MASKED(member_offset);
3461 if (bitfield_size) {
3462 safe_data = btf_show_start_type(show, member_type,
3464 data + bytes_offset);
3466 btf_bitfield_show(safe_data,
3468 bitfield_size, show);
3469 btf_show_end_type(show);
3471 ops = btf_type_ops(member_type);
3472 ops->show(btf, member_type, member->type,
3473 data + bytes_offset, bits8_offset, show);
3476 btf_show_end_member(show);
3479 btf_show_end_struct_type(show);
3482 static void btf_struct_show(const struct btf *btf, const struct btf_type *t,
3483 u32 type_id, void *data, u8 bits_offset,
3484 struct btf_show *show)
3486 const struct btf_member *m = show->state.member;
3489 * First check if any members would be shown (are non-zero).
3490 * See comments above "struct btf_show" definition for more
3491 * details on how this works at a high-level.
3493 if (show->state.depth > 0 && !(show->flags & BTF_SHOW_ZERO)) {
3494 if (!show->state.depth_check) {
3495 show->state.depth_check = show->state.depth + 1;
3496 show->state.depth_to_show = 0;
3498 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3499 /* Restore saved member data here */
3500 show->state.member = m;
3501 if (show->state.depth_check != show->state.depth + 1)
3503 show->state.depth_check = 0;
3505 if (show->state.depth_to_show <= show->state.depth)
3508 * Reaching here indicates we have recursed and found
3509 * non-zero child values.
3513 __btf_struct_show(btf, t, type_id, data, bits_offset, show);
3516 static struct btf_kind_operations struct_ops = {
3517 .check_meta = btf_struct_check_meta,
3518 .resolve = btf_struct_resolve,
3519 .check_member = btf_struct_check_member,
3520 .check_kflag_member = btf_generic_check_kflag_member,
3521 .log_details = btf_struct_log,
3522 .show = btf_struct_show,
3525 static int btf_enum_check_member(struct btf_verifier_env *env,
3526 const struct btf_type *struct_type,
3527 const struct btf_member *member,
3528 const struct btf_type *member_type)
3530 u32 struct_bits_off = member->offset;
3531 u32 struct_size, bytes_offset;
3533 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3534 btf_verifier_log_member(env, struct_type, member,
3535 "Member is not byte aligned");
3539 struct_size = struct_type->size;
3540 bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off);
3541 if (struct_size - bytes_offset < member_type->size) {
3542 btf_verifier_log_member(env, struct_type, member,
3543 "Member exceeds struct_size");
3550 static int btf_enum_check_kflag_member(struct btf_verifier_env *env,
3551 const struct btf_type *struct_type,
3552 const struct btf_member *member,
3553 const struct btf_type *member_type)
3555 u32 struct_bits_off, nr_bits, bytes_end, struct_size;
3556 u32 int_bitsize = sizeof(int) * BITS_PER_BYTE;
3558 struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset);
3559 nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset);
3561 if (BITS_PER_BYTE_MASKED(struct_bits_off)) {
3562 btf_verifier_log_member(env, struct_type, member,
3563 "Member is not byte aligned");
3567 nr_bits = int_bitsize;
3568 } else if (nr_bits > int_bitsize) {
3569 btf_verifier_log_member(env, struct_type, member,
3570 "Invalid member bitfield_size");
3574 struct_size = struct_type->size;
3575 bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits);
3576 if (struct_size < bytes_end) {
3577 btf_verifier_log_member(env, struct_type, member,
3578 "Member exceeds struct_size");
3585 static s32 btf_enum_check_meta(struct btf_verifier_env *env,
3586 const struct btf_type *t,
3589 const struct btf_enum *enums = btf_type_enum(t);
3590 struct btf *btf = env->btf;
3594 nr_enums = btf_type_vlen(t);
3595 meta_needed = nr_enums * sizeof(*enums);
3597 if (meta_left < meta_needed) {
3598 btf_verifier_log_basic(env, t,
3599 "meta_left:%u meta_needed:%u",
3600 meta_left, meta_needed);
3604 if (btf_type_kflag(t)) {
3605 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3609 if (t->size > 8 || !is_power_of_2(t->size)) {
3610 btf_verifier_log_type(env, t, "Unexpected size");
3614 /* enum type either no name or a valid one */
3616 !btf_name_valid_identifier(env->btf, t->name_off)) {
3617 btf_verifier_log_type(env, t, "Invalid name");
3621 btf_verifier_log_type(env, t, NULL);
3623 for (i = 0; i < nr_enums; i++) {
3624 if (!btf_name_offset_valid(btf, enums[i].name_off)) {
3625 btf_verifier_log(env, "\tInvalid name_offset:%u",
3630 /* enum member must have a valid name */
3631 if (!enums[i].name_off ||
3632 !btf_name_valid_identifier(btf, enums[i].name_off)) {
3633 btf_verifier_log_type(env, t, "Invalid name");
3637 if (env->log.level == BPF_LOG_KERNEL)
3639 btf_verifier_log(env, "\t%s val=%d\n",
3640 __btf_name_by_offset(btf, enums[i].name_off),
3647 static void btf_enum_log(struct btf_verifier_env *env,
3648 const struct btf_type *t)
3650 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
3653 static void btf_enum_show(const struct btf *btf, const struct btf_type *t,
3654 u32 type_id, void *data, u8 bits_offset,
3655 struct btf_show *show)
3657 const struct btf_enum *enums = btf_type_enum(t);
3658 u32 i, nr_enums = btf_type_vlen(t);
3662 safe_data = btf_show_start_type(show, t, type_id, data);
3666 v = *(int *)safe_data;
3668 for (i = 0; i < nr_enums; i++) {
3669 if (v != enums[i].val)
3672 btf_show_type_value(show, "%s",
3673 __btf_name_by_offset(btf,
3674 enums[i].name_off));
3676 btf_show_end_type(show);
3680 btf_show_type_value(show, "%d", v);
3681 btf_show_end_type(show);
3684 static struct btf_kind_operations enum_ops = {
3685 .check_meta = btf_enum_check_meta,
3686 .resolve = btf_df_resolve,
3687 .check_member = btf_enum_check_member,
3688 .check_kflag_member = btf_enum_check_kflag_member,
3689 .log_details = btf_enum_log,
3690 .show = btf_enum_show,
3693 static s32 btf_func_proto_check_meta(struct btf_verifier_env *env,
3694 const struct btf_type *t,
3697 u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param);
3699 if (meta_left < meta_needed) {
3700 btf_verifier_log_basic(env, t,
3701 "meta_left:%u meta_needed:%u",
3702 meta_left, meta_needed);
3707 btf_verifier_log_type(env, t, "Invalid name");
3711 if (btf_type_kflag(t)) {
3712 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3716 btf_verifier_log_type(env, t, NULL);
3721 static void btf_func_proto_log(struct btf_verifier_env *env,
3722 const struct btf_type *t)
3724 const struct btf_param *args = (const struct btf_param *)(t + 1);
3725 u16 nr_args = btf_type_vlen(t), i;
3727 btf_verifier_log(env, "return=%u args=(", t->type);
3729 btf_verifier_log(env, "void");
3733 if (nr_args == 1 && !args[0].type) {
3734 /* Only one vararg */
3735 btf_verifier_log(env, "vararg");
3739 btf_verifier_log(env, "%u %s", args[0].type,
3740 __btf_name_by_offset(env->btf,
3742 for (i = 1; i < nr_args - 1; i++)
3743 btf_verifier_log(env, ", %u %s", args[i].type,
3744 __btf_name_by_offset(env->btf,
3748 const struct btf_param *last_arg = &args[nr_args - 1];
3751 btf_verifier_log(env, ", %u %s", last_arg->type,
3752 __btf_name_by_offset(env->btf,
3753 last_arg->name_off));
3755 btf_verifier_log(env, ", vararg");
3759 btf_verifier_log(env, ")");
3762 static struct btf_kind_operations func_proto_ops = {
3763 .check_meta = btf_func_proto_check_meta,
3764 .resolve = btf_df_resolve,
3766 * BTF_KIND_FUNC_PROTO cannot be directly referred by
3767 * a struct's member.
3769 * It should be a function pointer instead.
3770 * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO)
3772 * Hence, there is no btf_func_check_member().
3774 .check_member = btf_df_check_member,
3775 .check_kflag_member = btf_df_check_kflag_member,
3776 .log_details = btf_func_proto_log,
3777 .show = btf_df_show,
3780 static s32 btf_func_check_meta(struct btf_verifier_env *env,
3781 const struct btf_type *t,
3785 !btf_name_valid_identifier(env->btf, t->name_off)) {
3786 btf_verifier_log_type(env, t, "Invalid name");
3790 if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) {
3791 btf_verifier_log_type(env, t, "Invalid func linkage");
3795 if (btf_type_kflag(t)) {
3796 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3800 btf_verifier_log_type(env, t, NULL);
3805 static int btf_func_resolve(struct btf_verifier_env *env,
3806 const struct resolve_vertex *v)
3808 const struct btf_type *t = v->t;
3809 u32 next_type_id = t->type;
3812 err = btf_func_check(env, t);
3816 env_stack_pop_resolved(env, next_type_id, 0);
3820 static struct btf_kind_operations func_ops = {
3821 .check_meta = btf_func_check_meta,
3822 .resolve = btf_func_resolve,
3823 .check_member = btf_df_check_member,
3824 .check_kflag_member = btf_df_check_kflag_member,
3825 .log_details = btf_ref_type_log,
3826 .show = btf_df_show,
3829 static s32 btf_var_check_meta(struct btf_verifier_env *env,
3830 const struct btf_type *t,
3833 const struct btf_var *var;
3834 u32 meta_needed = sizeof(*var);
3836 if (meta_left < meta_needed) {
3837 btf_verifier_log_basic(env, t,
3838 "meta_left:%u meta_needed:%u",
3839 meta_left, meta_needed);
3843 if (btf_type_vlen(t)) {
3844 btf_verifier_log_type(env, t, "vlen != 0");
3848 if (btf_type_kflag(t)) {
3849 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3854 !__btf_name_valid(env->btf, t->name_off, true)) {
3855 btf_verifier_log_type(env, t, "Invalid name");
3859 /* A var cannot be in type void */
3860 if (!t->type || !BTF_TYPE_ID_VALID(t->type)) {
3861 btf_verifier_log_type(env, t, "Invalid type_id");
3865 var = btf_type_var(t);
3866 if (var->linkage != BTF_VAR_STATIC &&
3867 var->linkage != BTF_VAR_GLOBAL_ALLOCATED) {
3868 btf_verifier_log_type(env, t, "Linkage not supported");
3872 btf_verifier_log_type(env, t, NULL);
3877 static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t)
3879 const struct btf_var *var = btf_type_var(t);
3881 btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage);
3884 static const struct btf_kind_operations var_ops = {
3885 .check_meta = btf_var_check_meta,
3886 .resolve = btf_var_resolve,
3887 .check_member = btf_df_check_member,
3888 .check_kflag_member = btf_df_check_kflag_member,
3889 .log_details = btf_var_log,
3890 .show = btf_var_show,
3893 static s32 btf_datasec_check_meta(struct btf_verifier_env *env,
3894 const struct btf_type *t,
3897 const struct btf_var_secinfo *vsi;
3898 u64 last_vsi_end_off = 0, sum = 0;
3901 meta_needed = btf_type_vlen(t) * sizeof(*vsi);
3902 if (meta_left < meta_needed) {
3903 btf_verifier_log_basic(env, t,
3904 "meta_left:%u meta_needed:%u",
3905 meta_left, meta_needed);
3910 btf_verifier_log_type(env, t, "size == 0");
3914 if (btf_type_kflag(t)) {
3915 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
3920 !btf_name_valid_section(env->btf, t->name_off)) {
3921 btf_verifier_log_type(env, t, "Invalid name");
3925 btf_verifier_log_type(env, t, NULL);
3927 for_each_vsi(i, t, vsi) {
3928 /* A var cannot be in type void */
3929 if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) {
3930 btf_verifier_log_vsi(env, t, vsi,
3935 if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) {
3936 btf_verifier_log_vsi(env, t, vsi,
3941 if (!vsi->size || vsi->size > t->size) {
3942 btf_verifier_log_vsi(env, t, vsi,
3947 last_vsi_end_off = vsi->offset + vsi->size;
3948 if (last_vsi_end_off > t->size) {
3949 btf_verifier_log_vsi(env, t, vsi,
3950 "Invalid offset+size");
3954 btf_verifier_log_vsi(env, t, vsi, NULL);
3958 if (t->size < sum) {
3959 btf_verifier_log_type(env, t, "Invalid btf_info size");
3966 static int btf_datasec_resolve(struct btf_verifier_env *env,
3967 const struct resolve_vertex *v)
3969 const struct btf_var_secinfo *vsi;
3970 struct btf *btf = env->btf;
3973 for_each_vsi_from(i, v->next_member, v->t, vsi) {
3974 u32 var_type_id = vsi->type, type_id, type_size = 0;
3975 const struct btf_type *var_type = btf_type_by_id(env->btf,
3977 if (!var_type || !btf_type_is_var(var_type)) {
3978 btf_verifier_log_vsi(env, v->t, vsi,
3979 "Not a VAR kind member");
3983 if (!env_type_is_resolve_sink(env, var_type) &&
3984 !env_type_is_resolved(env, var_type_id)) {
3985 env_stack_set_next_member(env, i + 1);
3986 return env_stack_push(env, var_type, var_type_id);
3989 type_id = var_type->type;
3990 if (!btf_type_id_size(btf, &type_id, &type_size)) {
3991 btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
3995 if (vsi->size < type_size) {
3996 btf_verifier_log_vsi(env, v->t, vsi, "Invalid size");
4001 env_stack_pop_resolved(env, 0, 0);
4005 static void btf_datasec_log(struct btf_verifier_env *env,
4006 const struct btf_type *t)
4008 btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t));
4011 static void btf_datasec_show(const struct btf *btf,
4012 const struct btf_type *t, u32 type_id,
4013 void *data, u8 bits_offset,
4014 struct btf_show *show)
4016 const struct btf_var_secinfo *vsi;
4017 const struct btf_type *var;
4020 if (!btf_show_start_type(show, t, type_id, data))
4023 btf_show_type_value(show, "section (\"%s\") = {",
4024 __btf_name_by_offset(btf, t->name_off));
4025 for_each_vsi(i, t, vsi) {
4026 var = btf_type_by_id(btf, vsi->type);
4028 btf_show(show, ",");
4029 btf_type_ops(var)->show(btf, var, vsi->type,
4030 data + vsi->offset, bits_offset, show);
4032 btf_show_end_type(show);
4035 static const struct btf_kind_operations datasec_ops = {
4036 .check_meta = btf_datasec_check_meta,
4037 .resolve = btf_datasec_resolve,
4038 .check_member = btf_df_check_member,
4039 .check_kflag_member = btf_df_check_kflag_member,
4040 .log_details = btf_datasec_log,
4041 .show = btf_datasec_show,
4044 static s32 btf_float_check_meta(struct btf_verifier_env *env,
4045 const struct btf_type *t,
4048 if (btf_type_vlen(t)) {
4049 btf_verifier_log_type(env, t, "vlen != 0");
4053 if (btf_type_kflag(t)) {
4054 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4058 if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
4060 btf_verifier_log_type(env, t, "Invalid type_size");
4064 btf_verifier_log_type(env, t, NULL);
4069 static int btf_float_check_member(struct btf_verifier_env *env,
4070 const struct btf_type *struct_type,
4071 const struct btf_member *member,
4072 const struct btf_type *member_type)
4074 u64 start_offset_bytes;
4075 u64 end_offset_bytes;
4080 /* Different architectures have different alignment requirements, so
4081 * here we check only for the reasonable minimum. This way we ensure
4082 * that types after CO-RE can pass the kernel BTF verifier.
4084 align_bytes = min_t(u64, sizeof(void *), member_type->size);
4085 align_bits = align_bytes * BITS_PER_BYTE;
4086 div64_u64_rem(member->offset, align_bits, &misalign_bits);
4087 if (misalign_bits) {
4088 btf_verifier_log_member(env, struct_type, member,
4089 "Member is not properly aligned");
4093 start_offset_bytes = member->offset / BITS_PER_BYTE;
4094 end_offset_bytes = start_offset_bytes + member_type->size;
4095 if (end_offset_bytes > struct_type->size) {
4096 btf_verifier_log_member(env, struct_type, member,
4097 "Member exceeds struct_size");
4104 static void btf_float_log(struct btf_verifier_env *env,
4105 const struct btf_type *t)
4107 btf_verifier_log(env, "size=%u", t->size);
4110 static const struct btf_kind_operations float_ops = {
4111 .check_meta = btf_float_check_meta,
4112 .resolve = btf_df_resolve,
4113 .check_member = btf_float_check_member,
4114 .check_kflag_member = btf_generic_check_kflag_member,
4115 .log_details = btf_float_log,
4116 .show = btf_df_show,
4119 static s32 btf_decl_tag_check_meta(struct btf_verifier_env *env,
4120 const struct btf_type *t,
4123 const struct btf_decl_tag *tag;
4124 u32 meta_needed = sizeof(*tag);
4128 if (meta_left < meta_needed) {
4129 btf_verifier_log_basic(env, t,
4130 "meta_left:%u meta_needed:%u",
4131 meta_left, meta_needed);
4135 value = btf_name_by_offset(env->btf, t->name_off);
4136 if (!value || !value[0]) {
4137 btf_verifier_log_type(env, t, "Invalid value");
4141 if (btf_type_vlen(t)) {
4142 btf_verifier_log_type(env, t, "vlen != 0");
4146 if (btf_type_kflag(t)) {
4147 btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
4151 component_idx = btf_type_decl_tag(t)->component_idx;
4152 if (component_idx < -1) {
4153 btf_verifier_log_type(env, t, "Invalid component_idx");
4157 btf_verifier_log_type(env, t, NULL);
4162 static int btf_decl_tag_resolve(struct btf_verifier_env *env,
4163 const struct resolve_vertex *v)
4165 const struct btf_type *next_type;
4166 const struct btf_type *t = v->t;
4167 u32 next_type_id = t->type;
4168 struct btf *btf = env->btf;
4172 next_type = btf_type_by_id(btf, next_type_id);
4173 if (!next_type || !btf_type_is_decl_tag_target(next_type)) {
4174 btf_verifier_log_type(env, v->t, "Invalid type_id");
4178 if (!env_type_is_resolve_sink(env, next_type) &&
4179 !env_type_is_resolved(env, next_type_id))
4180 return env_stack_push(env, next_type, next_type_id);
4182 component_idx = btf_type_decl_tag(t)->component_idx;
4183 if (component_idx != -1) {
4184 if (btf_type_is_var(next_type) || btf_type_is_typedef(next_type)) {
4185 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4189 if (btf_type_is_struct(next_type)) {
4190 vlen = btf_type_vlen(next_type);
4192 /* next_type should be a function */
4193 next_type = btf_type_by_id(btf, next_type->type);
4194 vlen = btf_type_vlen(next_type);
4197 if ((u32)component_idx >= vlen) {
4198 btf_verifier_log_type(env, v->t, "Invalid component_idx");
4203 env_stack_pop_resolved(env, next_type_id, 0);
4208 static void btf_decl_tag_log(struct btf_verifier_env *env, const struct btf_type *t)
4210 btf_verifier_log(env, "type=%u component_idx=%d", t->type,
4211 btf_type_decl_tag(t)->component_idx);
4214 static const struct btf_kind_operations decl_tag_ops = {
4215 .check_meta = btf_decl_tag_check_meta,
4216 .resolve = btf_decl_tag_resolve,
4217 .check_member = btf_df_check_member,
4218 .check_kflag_member = btf_df_check_kflag_member,
4219 .log_details = btf_decl_tag_log,
4220 .show = btf_df_show,
4223 static int btf_func_proto_check(struct btf_verifier_env *env,
4224 const struct btf_type *t)
4226 const struct btf_type *ret_type;
4227 const struct btf_param *args;
4228 const struct btf *btf;
4233 args = (const struct btf_param *)(t + 1);
4234 nr_args = btf_type_vlen(t);
4236 /* Check func return type which could be "void" (t->type == 0) */
4238 u32 ret_type_id = t->type;
4240 ret_type = btf_type_by_id(btf, ret_type_id);
4242 btf_verifier_log_type(env, t, "Invalid return type");
4246 if (btf_type_needs_resolve(ret_type) &&
4247 !env_type_is_resolved(env, ret_type_id)) {
4248 err = btf_resolve(env, ret_type, ret_type_id);
4253 /* Ensure the return type is a type that has a size */
4254 if (!btf_type_id_size(btf, &ret_type_id, NULL)) {
4255 btf_verifier_log_type(env, t, "Invalid return type");
4263 /* Last func arg type_id could be 0 if it is a vararg */
4264 if (!args[nr_args - 1].type) {
4265 if (args[nr_args - 1].name_off) {
4266 btf_verifier_log_type(env, t, "Invalid arg#%u",
4274 for (i = 0; i < nr_args; i++) {
4275 const struct btf_type *arg_type;
4278 arg_type_id = args[i].type;
4279 arg_type = btf_type_by_id(btf, arg_type_id);
4281 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4286 if (args[i].name_off &&
4287 (!btf_name_offset_valid(btf, args[i].name_off) ||
4288 !btf_name_valid_identifier(btf, args[i].name_off))) {
4289 btf_verifier_log_type(env, t,
4290 "Invalid arg#%u", i + 1);
4295 if (btf_type_needs_resolve(arg_type) &&
4296 !env_type_is_resolved(env, arg_type_id)) {
4297 err = btf_resolve(env, arg_type, arg_type_id);
4302 if (!btf_type_id_size(btf, &arg_type_id, NULL)) {
4303 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4312 static int btf_func_check(struct btf_verifier_env *env,
4313 const struct btf_type *t)
4315 const struct btf_type *proto_type;
4316 const struct btf_param *args;
4317 const struct btf *btf;
4321 proto_type = btf_type_by_id(btf, t->type);
4323 if (!proto_type || !btf_type_is_func_proto(proto_type)) {
4324 btf_verifier_log_type(env, t, "Invalid type_id");
4328 args = (const struct btf_param *)(proto_type + 1);
4329 nr_args = btf_type_vlen(proto_type);
4330 for (i = 0; i < nr_args; i++) {
4331 if (!args[i].name_off && args[i].type) {
4332 btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1);
4340 static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
4341 [BTF_KIND_INT] = &int_ops,
4342 [BTF_KIND_PTR] = &ptr_ops,
4343 [BTF_KIND_ARRAY] = &array_ops,
4344 [BTF_KIND_STRUCT] = &struct_ops,
4345 [BTF_KIND_UNION] = &struct_ops,
4346 [BTF_KIND_ENUM] = &enum_ops,
4347 [BTF_KIND_FWD] = &fwd_ops,
4348 [BTF_KIND_TYPEDEF] = &modifier_ops,
4349 [BTF_KIND_VOLATILE] = &modifier_ops,
4350 [BTF_KIND_CONST] = &modifier_ops,
4351 [BTF_KIND_RESTRICT] = &modifier_ops,
4352 [BTF_KIND_FUNC] = &func_ops,
4353 [BTF_KIND_FUNC_PROTO] = &func_proto_ops,
4354 [BTF_KIND_VAR] = &var_ops,
4355 [BTF_KIND_DATASEC] = &datasec_ops,
4356 [BTF_KIND_FLOAT] = &float_ops,
4357 [BTF_KIND_DECL_TAG] = &decl_tag_ops,
4358 [BTF_KIND_TYPE_TAG] = &modifier_ops,
4361 static s32 btf_check_meta(struct btf_verifier_env *env,
4362 const struct btf_type *t,
4365 u32 saved_meta_left = meta_left;
4368 if (meta_left < sizeof(*t)) {
4369 btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu",
4370 env->log_type_id, meta_left, sizeof(*t));
4373 meta_left -= sizeof(*t);
4375 if (t->info & ~BTF_INFO_MASK) {
4376 btf_verifier_log(env, "[%u] Invalid btf_info:%x",
4377 env->log_type_id, t->info);
4381 if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX ||
4382 BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) {
4383 btf_verifier_log(env, "[%u] Invalid kind:%u",
4384 env->log_type_id, BTF_INFO_KIND(t->info));
4388 if (!btf_name_offset_valid(env->btf, t->name_off)) {
4389 btf_verifier_log(env, "[%u] Invalid name_offset:%u",
4390 env->log_type_id, t->name_off);
4394 var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left);
4395 if (var_meta_size < 0)
4396 return var_meta_size;
4398 meta_left -= var_meta_size;
4400 return saved_meta_left - meta_left;
4403 static int btf_check_all_metas(struct btf_verifier_env *env)
4405 struct btf *btf = env->btf;
4406 struct btf_header *hdr;
4410 cur = btf->nohdr_data + hdr->type_off;
4411 end = cur + hdr->type_len;
4413 env->log_type_id = btf->base_btf ? btf->start_id : 1;
4415 struct btf_type *t = cur;
4418 meta_size = btf_check_meta(env, t, end - cur);
4422 btf_add_type(env, t);
4430 static bool btf_resolve_valid(struct btf_verifier_env *env,
4431 const struct btf_type *t,
4434 struct btf *btf = env->btf;
4436 if (!env_type_is_resolved(env, type_id))
4439 if (btf_type_is_struct(t) || btf_type_is_datasec(t))
4440 return !btf_resolved_type_id(btf, type_id) &&
4441 !btf_resolved_type_size(btf, type_id);
4443 if (btf_type_is_decl_tag(t) || btf_type_is_func(t))
4444 return btf_resolved_type_id(btf, type_id) &&
4445 !btf_resolved_type_size(btf, type_id);
4447 if (btf_type_is_modifier(t) || btf_type_is_ptr(t) ||
4448 btf_type_is_var(t)) {
4449 t = btf_type_id_resolve(btf, &type_id);
4451 !btf_type_is_modifier(t) &&
4452 !btf_type_is_var(t) &&
4453 !btf_type_is_datasec(t);
4456 if (btf_type_is_array(t)) {
4457 const struct btf_array *array = btf_type_array(t);
4458 const struct btf_type *elem_type;
4459 u32 elem_type_id = array->type;
4462 elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size);
4463 return elem_type && !btf_type_is_modifier(elem_type) &&
4464 (array->nelems * elem_size ==
4465 btf_resolved_type_size(btf, type_id));
4471 static int btf_resolve(struct btf_verifier_env *env,
4472 const struct btf_type *t, u32 type_id)
4474 u32 save_log_type_id = env->log_type_id;
4475 const struct resolve_vertex *v;
4478 env->resolve_mode = RESOLVE_TBD;
4479 env_stack_push(env, t, type_id);
4480 while (!err && (v = env_stack_peak(env))) {
4481 env->log_type_id = v->type_id;
4482 err = btf_type_ops(v->t)->resolve(env, v);
4485 env->log_type_id = type_id;
4486 if (err == -E2BIG) {
4487 btf_verifier_log_type(env, t,
4488 "Exceeded max resolving depth:%u",
4490 } else if (err == -EEXIST) {
4491 btf_verifier_log_type(env, t, "Loop detected");
4494 /* Final sanity check */
4495 if (!err && !btf_resolve_valid(env, t, type_id)) {
4496 btf_verifier_log_type(env, t, "Invalid resolve state");
4500 env->log_type_id = save_log_type_id;
4504 static int btf_check_all_types(struct btf_verifier_env *env)
4506 struct btf *btf = env->btf;
4507 const struct btf_type *t;
4511 err = env_resolve_init(env);
4516 for (i = btf->base_btf ? 0 : 1; i < btf->nr_types; i++) {
4517 type_id = btf->start_id + i;
4518 t = btf_type_by_id(btf, type_id);
4520 env->log_type_id = type_id;
4521 if (btf_type_needs_resolve(t) &&
4522 !env_type_is_resolved(env, type_id)) {
4523 err = btf_resolve(env, t, type_id);
4528 if (btf_type_is_func_proto(t)) {
4529 err = btf_func_proto_check(env, t);
4538 static int btf_parse_type_sec(struct btf_verifier_env *env)
4540 const struct btf_header *hdr = &env->btf->hdr;
4543 /* Type section must align to 4 bytes */
4544 if (hdr->type_off & (sizeof(u32) - 1)) {
4545 btf_verifier_log(env, "Unaligned type_off");
4549 if (!env->btf->base_btf && !hdr->type_len) {
4550 btf_verifier_log(env, "No type found");
4554 err = btf_check_all_metas(env);
4558 return btf_check_all_types(env);
4561 static int btf_parse_str_sec(struct btf_verifier_env *env)
4563 const struct btf_header *hdr;
4564 struct btf *btf = env->btf;
4565 const char *start, *end;
4568 start = btf->nohdr_data + hdr->str_off;
4569 end = start + hdr->str_len;
4571 if (end != btf->data + btf->data_size) {
4572 btf_verifier_log(env, "String section is not at the end");
4576 btf->strings = start;
4578 if (btf->base_btf && !hdr->str_len)
4580 if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || end[-1]) {
4581 btf_verifier_log(env, "Invalid string section");
4584 if (!btf->base_btf && start[0]) {
4585 btf_verifier_log(env, "Invalid string section");
4592 static const size_t btf_sec_info_offset[] = {
4593 offsetof(struct btf_header, type_off),
4594 offsetof(struct btf_header, str_off),
4597 static int btf_sec_info_cmp(const void *a, const void *b)
4599 const struct btf_sec_info *x = a;
4600 const struct btf_sec_info *y = b;
4602 return (int)(x->off - y->off) ? : (int)(x->len - y->len);
4605 static int btf_check_sec_info(struct btf_verifier_env *env,
4608 struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
4609 u32 total, expected_total, i;
4610 const struct btf_header *hdr;
4611 const struct btf *btf;
4616 /* Populate the secs from hdr */
4617 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
4618 secs[i] = *(struct btf_sec_info *)((void *)hdr +
4619 btf_sec_info_offset[i]);
4621 sort(secs, ARRAY_SIZE(btf_sec_info_offset),
4622 sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
4624 /* Check for gaps and overlap among sections */
4626 expected_total = btf_data_size - hdr->hdr_len;
4627 for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
4628 if (expected_total < secs[i].off) {
4629 btf_verifier_log(env, "Invalid section offset");
4632 if (total < secs[i].off) {
4634 btf_verifier_log(env, "Unsupported section found");
4637 if (total > secs[i].off) {
4638 btf_verifier_log(env, "Section overlap found");
4641 if (expected_total - total < secs[i].len) {
4642 btf_verifier_log(env,
4643 "Total section length too long");
4646 total += secs[i].len;
4649 /* There is data other than hdr and known sections */
4650 if (expected_total != total) {
4651 btf_verifier_log(env, "Unsupported section found");
4658 static int btf_parse_hdr(struct btf_verifier_env *env)
4660 u32 hdr_len, hdr_copy, btf_data_size;
4661 const struct btf_header *hdr;
4666 btf_data_size = btf->data_size;
4668 if (btf_data_size < offsetofend(struct btf_header, hdr_len)) {
4669 btf_verifier_log(env, "hdr_len not found");
4674 hdr_len = hdr->hdr_len;
4675 if (btf_data_size < hdr_len) {
4676 btf_verifier_log(env, "btf_header not found");
4680 /* Ensure the unsupported header fields are zero */
4681 if (hdr_len > sizeof(btf->hdr)) {
4682 u8 *expected_zero = btf->data + sizeof(btf->hdr);
4683 u8 *end = btf->data + hdr_len;
4685 for (; expected_zero < end; expected_zero++) {
4686 if (*expected_zero) {
4687 btf_verifier_log(env, "Unsupported btf_header");
4693 hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr));
4694 memcpy(&btf->hdr, btf->data, hdr_copy);
4698 btf_verifier_log_hdr(env, btf_data_size);
4700 if (hdr->magic != BTF_MAGIC) {
4701 btf_verifier_log(env, "Invalid magic");
4705 if (hdr->version != BTF_VERSION) {
4706 btf_verifier_log(env, "Unsupported version");
4711 btf_verifier_log(env, "Unsupported flags");
4715 if (!btf->base_btf && btf_data_size == hdr->hdr_len) {
4716 btf_verifier_log(env, "No data");
4720 err = btf_check_sec_info(env, btf_data_size);
4727 static int btf_check_type_tags(struct btf_verifier_env *env,
4728 struct btf *btf, int start_id)
4730 int i, n, good_id = start_id - 1;
4733 n = btf_nr_types(btf);
4734 for (i = start_id; i < n; i++) {
4735 const struct btf_type *t;
4738 t = btf_type_by_id(btf, i);
4741 if (!btf_type_is_modifier(t))
4746 in_tags = btf_type_is_type_tag(t);
4747 while (btf_type_is_modifier(t)) {
4748 if (btf_type_is_type_tag(t)) {
4750 btf_verifier_log(env, "Type tags don't precede modifiers");
4753 } else if (in_tags) {
4756 if (cur_id <= good_id)
4758 /* Move to next type */
4760 t = btf_type_by_id(btf, cur_id);
4769 static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
4770 u32 log_level, char __user *log_ubuf, u32 log_size)
4772 struct btf_verifier_env *env = NULL;
4773 struct bpf_verifier_log *log;
4774 struct btf *btf = NULL;
4778 if (btf_data_size > BTF_MAX_SIZE)
4779 return ERR_PTR(-E2BIG);
4781 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
4783 return ERR_PTR(-ENOMEM);
4786 if (log_level || log_ubuf || log_size) {
4787 /* user requested verbose verifier output
4788 * and supplied buffer to store the verification trace
4790 log->level = log_level;
4791 log->ubuf = log_ubuf;
4792 log->len_total = log_size;
4794 /* log attributes have to be sane */
4795 if (!bpf_verifier_log_attr_valid(log)) {
4801 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
4808 data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN);
4815 btf->data_size = btf_data_size;
4817 if (copy_from_bpfptr(data, btf_data, btf_data_size)) {
4822 err = btf_parse_hdr(env);
4826 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
4828 err = btf_parse_str_sec(env);
4832 err = btf_parse_type_sec(env);
4836 err = btf_check_type_tags(env, btf, 1);
4840 if (log->level && bpf_verifier_log_full(log)) {
4845 btf_verifier_env_free(env);
4846 refcount_set(&btf->refcnt, 1);
4850 btf_verifier_env_free(env);
4853 return ERR_PTR(err);
4856 extern char __weak __start_BTF[];
4857 extern char __weak __stop_BTF[];
4858 extern struct btf *btf_vmlinux;
4860 #define BPF_MAP_TYPE(_id, _ops)
4861 #define BPF_LINK_TYPE(_id, _name)
4863 struct bpf_ctx_convert {
4864 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4865 prog_ctx_type _id##_prog; \
4866 kern_ctx_type _id##_kern;
4867 #include <linux/bpf_types.h>
4868 #undef BPF_PROG_TYPE
4870 /* 't' is written once under lock. Read many times. */
4871 const struct btf_type *t;
4874 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4876 #include <linux/bpf_types.h>
4877 #undef BPF_PROG_TYPE
4878 __ctx_convert_unused, /* to avoid empty enum in extreme .config */
4880 static u8 bpf_ctx_convert_map[] = {
4881 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
4882 [_id] = __ctx_convert##_id,
4883 #include <linux/bpf_types.h>
4884 #undef BPF_PROG_TYPE
4885 0, /* avoid empty array */
4888 #undef BPF_LINK_TYPE
4890 static const struct btf_member *
4891 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
4892 const struct btf_type *t, enum bpf_prog_type prog_type,
4895 const struct btf_type *conv_struct;
4896 const struct btf_type *ctx_struct;
4897 const struct btf_member *ctx_type;
4898 const char *tname, *ctx_tname;
4900 conv_struct = bpf_ctx_convert.t;
4902 bpf_log(log, "btf_vmlinux is malformed\n");
4905 t = btf_type_by_id(btf, t->type);
4906 while (btf_type_is_modifier(t))
4907 t = btf_type_by_id(btf, t->type);
4908 if (!btf_type_is_struct(t)) {
4909 /* Only pointer to struct is supported for now.
4910 * That means that BPF_PROG_TYPE_TRACEPOINT with BTF
4911 * is not supported yet.
4912 * BPF_PROG_TYPE_RAW_TRACEPOINT is fine.
4916 tname = btf_name_by_offset(btf, t->name_off);
4918 bpf_log(log, "arg#%d struct doesn't have a name\n", arg);
4921 /* prog_type is valid bpf program type. No need for bounds check. */
4922 ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2;
4923 /* ctx_struct is a pointer to prog_ctx_type in vmlinux.
4924 * Like 'struct __sk_buff'
4926 ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type);
4928 /* should not happen */
4930 ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off);
4932 /* should not happen */
4933 bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n");
4936 /* only compare that prog's ctx type name is the same as
4937 * kernel expects. No need to compare field by field.
4938 * It's ok for bpf prog to do:
4939 * struct __sk_buff {};
4940 * int socket_filter_bpf_prog(struct __sk_buff *skb)
4941 * { // no fields of skb are ever used }
4943 if (strcmp(ctx_tname, tname))
4948 static const struct bpf_map_ops * const btf_vmlinux_map_ops[] = {
4949 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type)
4950 #define BPF_LINK_TYPE(_id, _name)
4951 #define BPF_MAP_TYPE(_id, _ops) \
4953 #include <linux/bpf_types.h>
4954 #undef BPF_PROG_TYPE
4955 #undef BPF_LINK_TYPE
4959 static int btf_vmlinux_map_ids_init(const struct btf *btf,
4960 struct bpf_verifier_log *log)
4962 const struct bpf_map_ops *ops;
4965 for (i = 0; i < ARRAY_SIZE(btf_vmlinux_map_ops); ++i) {
4966 ops = btf_vmlinux_map_ops[i];
4967 if (!ops || (!ops->map_btf_name && !ops->map_btf_id))
4969 if (!ops->map_btf_name || !ops->map_btf_id) {
4970 bpf_log(log, "map type %d is misconfigured\n", i);
4973 btf_id = btf_find_by_name_kind(btf, ops->map_btf_name,
4977 *ops->map_btf_id = btf_id;
4983 static int btf_translate_to_vmlinux(struct bpf_verifier_log *log,
4985 const struct btf_type *t,
4986 enum bpf_prog_type prog_type,
4989 const struct btf_member *prog_ctx_type, *kern_ctx_type;
4991 prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg);
4994 kern_ctx_type = prog_ctx_type + 1;
4995 return kern_ctx_type->type;
4998 BTF_ID_LIST(bpf_ctx_convert_btf_id)
4999 BTF_ID(struct, bpf_ctx_convert)
5001 struct btf *btf_parse_vmlinux(void)
5003 struct btf_verifier_env *env = NULL;
5004 struct bpf_verifier_log *log;
5005 struct btf *btf = NULL;
5008 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5010 return ERR_PTR(-ENOMEM);
5013 log->level = BPF_LOG_KERNEL;
5015 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5022 btf->data = __start_BTF;
5023 btf->data_size = __stop_BTF - __start_BTF;
5024 btf->kernel_btf = true;
5025 snprintf(btf->name, sizeof(btf->name), "vmlinux");
5027 err = btf_parse_hdr(env);
5031 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5033 err = btf_parse_str_sec(env);
5037 err = btf_check_all_metas(env);
5041 err = btf_check_type_tags(env, btf, 1);
5045 /* btf_parse_vmlinux() runs under bpf_verifier_lock */
5046 bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
5048 /* find bpf map structs for map_ptr access checking */
5049 err = btf_vmlinux_map_ids_init(btf, log);
5053 bpf_struct_ops_init(btf, log);
5055 refcount_set(&btf->refcnt, 1);
5057 err = btf_alloc_id(btf);
5061 btf_verifier_env_free(env);
5065 btf_verifier_env_free(env);
5070 return ERR_PTR(err);
5073 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
5075 static struct btf *btf_parse_module(const char *module_name, const void *data, unsigned int data_size)
5077 struct btf_verifier_env *env = NULL;
5078 struct bpf_verifier_log *log;
5079 struct btf *btf = NULL, *base_btf;
5082 base_btf = bpf_get_btf_vmlinux();
5083 if (IS_ERR(base_btf))
5086 return ERR_PTR(-EINVAL);
5088 env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN);
5090 return ERR_PTR(-ENOMEM);
5093 log->level = BPF_LOG_KERNEL;
5095 btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN);
5102 btf->base_btf = base_btf;
5103 btf->start_id = base_btf->nr_types;
5104 btf->start_str_off = base_btf->hdr.str_len;
5105 btf->kernel_btf = true;
5106 snprintf(btf->name, sizeof(btf->name), "%s", module_name);
5108 btf->data = kvmalloc(data_size, GFP_KERNEL | __GFP_NOWARN);
5113 memcpy(btf->data, data, data_size);
5114 btf->data_size = data_size;
5116 err = btf_parse_hdr(env);
5120 btf->nohdr_data = btf->data + btf->hdr.hdr_len;
5122 err = btf_parse_str_sec(env);
5126 err = btf_check_all_metas(env);
5130 err = btf_check_type_tags(env, btf, btf_nr_types(base_btf));
5134 btf_verifier_env_free(env);
5135 refcount_set(&btf->refcnt, 1);
5139 btf_verifier_env_free(env);
5145 return ERR_PTR(err);
5148 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
5150 struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog)
5152 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5155 return tgt_prog->aux->btf;
5157 return prog->aux->attach_btf;
5160 static bool is_int_ptr(struct btf *btf, const struct btf_type *t)
5162 /* t comes in already as a pointer */
5163 t = btf_type_by_id(btf, t->type);
5166 if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST)
5167 t = btf_type_by_id(btf, t->type);
5169 return btf_type_is_int(t);
5172 bool btf_ctx_access(int off, int size, enum bpf_access_type type,
5173 const struct bpf_prog *prog,
5174 struct bpf_insn_access_aux *info)
5176 const struct btf_type *t = prog->aux->attach_func_proto;
5177 struct bpf_prog *tgt_prog = prog->aux->dst_prog;
5178 struct btf *btf = bpf_prog_get_target_btf(prog);
5179 const char *tname = prog->aux->attach_func_name;
5180 struct bpf_verifier_log *log = info->log;
5181 const struct btf_param *args;
5182 const char *tag_value;
5187 bpf_log(log, "func '%s' offset %d is not multiple of 8\n",
5192 args = (const struct btf_param *)(t + 1);
5193 /* if (t == NULL) Fall back to default BPF prog with
5194 * MAX_BPF_FUNC_REG_ARGS u64 arguments.
5196 nr_args = t ? btf_type_vlen(t) : MAX_BPF_FUNC_REG_ARGS;
5197 if (prog->aux->attach_btf_trace) {
5198 /* skip first 'void *__data' argument in btf_trace_##name typedef */
5203 if (arg > nr_args) {
5204 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5209 if (arg == nr_args) {
5210 switch (prog->expected_attach_type) {
5212 case BPF_TRACE_FEXIT:
5213 /* When LSM programs are attached to void LSM hooks
5214 * they use FEXIT trampolines and when attached to
5215 * int LSM hooks, they use MODIFY_RETURN trampolines.
5217 * While the LSM programs are BPF_MODIFY_RETURN-like
5220 * if (ret_type != 'int')
5223 * is _not_ done here. This is still safe as LSM hooks
5224 * have only void and int return types.
5228 t = btf_type_by_id(btf, t->type);
5230 case BPF_MODIFY_RETURN:
5231 /* For now the BPF_MODIFY_RETURN can only be attached to
5232 * functions that return an int.
5237 t = btf_type_skip_modifiers(btf, t->type, NULL);
5238 if (!btf_type_is_small_int(t)) {
5240 "ret type %s not allowed for fmod_ret\n",
5241 btf_kind_str[BTF_INFO_KIND(t->info)]);
5246 bpf_log(log, "func '%s' doesn't have %d-th argument\n",
5252 /* Default prog with MAX_BPF_FUNC_REG_ARGS args */
5254 t = btf_type_by_id(btf, args[arg].type);
5257 /* skip modifiers */
5258 while (btf_type_is_modifier(t))
5259 t = btf_type_by_id(btf, t->type);
5260 if (btf_type_is_small_int(t) || btf_type_is_enum(t))
5261 /* accessing a scalar */
5263 if (!btf_type_is_ptr(t)) {
5265 "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n",
5267 __btf_name_by_offset(btf, t->name_off),
5268 btf_kind_str[BTF_INFO_KIND(t->info)]);
5272 /* check for PTR_TO_RDONLY_BUF_OR_NULL or PTR_TO_RDWR_BUF_OR_NULL */
5273 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5274 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5277 type = base_type(ctx_arg_info->reg_type);
5278 flag = type_flag(ctx_arg_info->reg_type);
5279 if (ctx_arg_info->offset == off && type == PTR_TO_BUF &&
5280 (flag & PTR_MAYBE_NULL)) {
5281 info->reg_type = ctx_arg_info->reg_type;
5287 /* This is a pointer to void.
5288 * It is the same as scalar from the verifier safety pov.
5289 * No further pointer walking is allowed.
5293 if (is_int_ptr(btf, t))
5296 /* this is a pointer to another type */
5297 for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
5298 const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
5300 if (ctx_arg_info->offset == off) {
5301 if (!ctx_arg_info->btf_id) {
5302 bpf_log(log,"invalid btf_id for context argument offset %u\n", off);
5306 info->reg_type = ctx_arg_info->reg_type;
5307 info->btf = btf_vmlinux;
5308 info->btf_id = ctx_arg_info->btf_id;
5313 info->reg_type = PTR_TO_BTF_ID;
5315 enum bpf_prog_type tgt_type;
5317 if (tgt_prog->type == BPF_PROG_TYPE_EXT)
5318 tgt_type = tgt_prog->aux->saved_dst_prog_type;
5320 tgt_type = tgt_prog->type;
5322 ret = btf_translate_to_vmlinux(log, btf, t, tgt_type, arg);
5324 info->btf = btf_vmlinux;
5333 info->btf_id = t->type;
5334 t = btf_type_by_id(btf, t->type);
5336 if (btf_type_is_type_tag(t)) {
5337 tag_value = __btf_name_by_offset(btf, t->name_off);
5338 if (strcmp(tag_value, "user") == 0)
5339 info->reg_type |= MEM_USER;
5340 if (strcmp(tag_value, "percpu") == 0)
5341 info->reg_type |= MEM_PERCPU;
5344 /* skip modifiers */
5345 while (btf_type_is_modifier(t)) {
5346 info->btf_id = t->type;
5347 t = btf_type_by_id(btf, t->type);
5349 if (!btf_type_is_struct(t)) {
5351 "func '%s' arg%d type %s is not a struct\n",
5352 tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]);
5355 bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n",
5356 tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)],
5357 __btf_name_by_offset(btf, t->name_off));
5361 enum bpf_struct_walk_result {
5368 static int btf_struct_walk(struct bpf_verifier_log *log, const struct btf *btf,
5369 const struct btf_type *t, int off, int size,
5370 u32 *next_btf_id, enum bpf_type_flag *flag)
5372 u32 i, moff, mtrue_end, msize = 0, total_nelems = 0;
5373 const struct btf_type *mtype, *elem_type = NULL;
5374 const struct btf_member *member;
5375 const char *tname, *mname, *tag_value;
5376 u32 vlen, elem_id, mid;
5379 tname = __btf_name_by_offset(btf, t->name_off);
5380 if (!btf_type_is_struct(t)) {
5381 bpf_log(log, "Type '%s' is not a struct\n", tname);
5385 vlen = btf_type_vlen(t);
5386 if (off + size > t->size) {
5387 /* If the last element is a variable size array, we may
5388 * need to relax the rule.
5390 struct btf_array *array_elem;
5395 member = btf_type_member(t) + vlen - 1;
5396 mtype = btf_type_skip_modifiers(btf, member->type,
5398 if (!btf_type_is_array(mtype))
5401 array_elem = (struct btf_array *)(mtype + 1);
5402 if (array_elem->nelems != 0)
5405 moff = __btf_member_bit_offset(t, member) / 8;
5409 /* Only allow structure for now, can be relaxed for
5410 * other types later.
5412 t = btf_type_skip_modifiers(btf, array_elem->type,
5414 if (!btf_type_is_struct(t))
5417 off = (off - moff) % t->size;
5421 bpf_log(log, "access beyond struct %s at off %u size %u\n",
5426 for_each_member(i, t, member) {
5427 /* offset of the field in bytes */
5428 moff = __btf_member_bit_offset(t, member) / 8;
5429 if (off + size <= moff)
5430 /* won't find anything, field is already too far */
5433 if (__btf_member_bitfield_size(t, member)) {
5434 u32 end_bit = __btf_member_bit_offset(t, member) +
5435 __btf_member_bitfield_size(t, member);
5437 /* off <= moff instead of off == moff because clang
5438 * does not generate a BTF member for anonymous
5439 * bitfield like the ":16" here:
5446 BITS_ROUNDUP_BYTES(end_bit) <= off + size)
5449 /* off may be accessing a following member
5453 * Doing partial access at either end of this
5454 * bitfield. Continue on this case also to
5455 * treat it as not accessing this bitfield
5456 * and eventually error out as field not
5457 * found to keep it simple.
5458 * It could be relaxed if there was a legit
5459 * partial access case later.
5464 /* In case of "off" is pointing to holes of a struct */
5468 /* type of the field */
5470 mtype = btf_type_by_id(btf, member->type);
5471 mname = __btf_name_by_offset(btf, member->name_off);
5473 mtype = __btf_resolve_size(btf, mtype, &msize,
5474 &elem_type, &elem_id, &total_nelems,
5476 if (IS_ERR(mtype)) {
5477 bpf_log(log, "field %s doesn't have size\n", mname);
5481 mtrue_end = moff + msize;
5482 if (off >= mtrue_end)
5483 /* no overlap with member, keep iterating */
5486 if (btf_type_is_array(mtype)) {
5489 /* __btf_resolve_size() above helps to
5490 * linearize a multi-dimensional array.
5492 * The logic here is treating an array
5493 * in a struct as the following way:
5496 * struct inner array[2][2];
5502 * struct inner array_elem0;
5503 * struct inner array_elem1;
5504 * struct inner array_elem2;
5505 * struct inner array_elem3;
5508 * When accessing outer->array[1][0], it moves
5509 * moff to "array_elem2", set mtype to
5510 * "struct inner", and msize also becomes
5511 * sizeof(struct inner). Then most of the
5512 * remaining logic will fall through without
5513 * caring the current member is an array or
5516 * Unlike mtype/msize/moff, mtrue_end does not
5517 * change. The naming difference ("_true") tells
5518 * that it is not always corresponding to
5519 * the current mtype/msize/moff.
5520 * It is the true end of the current
5521 * member (i.e. array in this case). That
5522 * will allow an int array to be accessed like
5524 * i.e. allow access beyond the size of
5525 * the array's element as long as it is
5526 * within the mtrue_end boundary.
5529 /* skip empty array */
5530 if (moff == mtrue_end)
5533 msize /= total_nelems;
5534 elem_idx = (off - moff) / msize;
5535 moff += elem_idx * msize;
5540 /* the 'off' we're looking for is either equal to start
5541 * of this field or inside of this struct
5543 if (btf_type_is_struct(mtype)) {
5544 /* our field must be inside that union or struct */
5547 /* return if the offset matches the member offset */
5553 /* adjust offset we're looking for */
5558 if (btf_type_is_ptr(mtype)) {
5559 const struct btf_type *stype, *t;
5560 enum bpf_type_flag tmp_flag = 0;
5563 if (msize != size || off != moff) {
5565 "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n",
5566 mname, moff, tname, off, size);
5570 /* check type tag */
5571 t = btf_type_by_id(btf, mtype->type);
5572 if (btf_type_is_type_tag(t)) {
5573 tag_value = __btf_name_by_offset(btf, t->name_off);
5574 /* check __user tag */
5575 if (strcmp(tag_value, "user") == 0)
5576 tmp_flag = MEM_USER;
5577 /* check __percpu tag */
5578 if (strcmp(tag_value, "percpu") == 0)
5579 tmp_flag = MEM_PERCPU;
5582 stype = btf_type_skip_modifiers(btf, mtype->type, &id);
5583 if (btf_type_is_struct(stype)) {
5590 /* Allow more flexible access within an int as long as
5591 * it is within mtrue_end.
5592 * Since mtrue_end could be the end of an array,
5593 * that also allows using an array of int as a scratch
5594 * space. e.g. skb->cb[].
5596 if (off + size > mtrue_end) {
5598 "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n",
5599 mname, mtrue_end, tname, off, size);
5605 bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off);
5609 int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
5610 const struct btf_type *t, int off, int size,
5611 enum bpf_access_type atype __maybe_unused,
5612 u32 *next_btf_id, enum bpf_type_flag *flag)
5614 enum bpf_type_flag tmp_flag = 0;
5619 err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
5623 /* If we found the pointer or scalar on t+off,
5628 return PTR_TO_BTF_ID;
5630 return SCALAR_VALUE;
5632 /* We found nested struct, so continue the search
5633 * by diving in it. At this point the offset is
5634 * aligned with the new type, so set it to 0.
5636 t = btf_type_by_id(btf, id);
5640 /* It's either error or unknown return value..
5643 if (WARN_ONCE(err > 0, "unknown btf_struct_walk return value"))
5652 /* Check that two BTF types, each specified as an BTF object + id, are exactly
5653 * the same. Trivial ID check is not enough due to module BTFs, because we can
5654 * end up with two different module BTFs, but IDs point to the common type in
5657 static bool btf_types_are_same(const struct btf *btf1, u32 id1,
5658 const struct btf *btf2, u32 id2)
5664 return btf_type_by_id(btf1, id1) == btf_type_by_id(btf2, id2);
5667 bool btf_struct_ids_match(struct bpf_verifier_log *log,
5668 const struct btf *btf, u32 id, int off,
5669 const struct btf *need_btf, u32 need_type_id)
5671 const struct btf_type *type;
5672 enum bpf_type_flag flag;
5675 /* Are we already done? */
5676 if (off == 0 && btf_types_are_same(btf, id, need_btf, need_type_id))
5680 type = btf_type_by_id(btf, id);
5683 err = btf_struct_walk(log, btf, type, off, 1, &id, &flag);
5684 if (err != WALK_STRUCT)
5687 /* We found nested struct object. If it matches
5688 * the requested ID, we're done. Otherwise let's
5689 * continue the search with offset 0 in the new
5692 if (!btf_types_are_same(btf, id, need_btf, need_type_id)) {
5700 static int __get_type_size(struct btf *btf, u32 btf_id,
5701 const struct btf_type **bad_type)
5703 const struct btf_type *t;
5708 t = btf_type_by_id(btf, btf_id);
5709 while (t && btf_type_is_modifier(t))
5710 t = btf_type_by_id(btf, t->type);
5712 *bad_type = btf_type_by_id(btf, 0);
5715 if (btf_type_is_ptr(t))
5716 /* kernel size of pointer. Not BPF's size of pointer*/
5717 return sizeof(void *);
5718 if (btf_type_is_int(t) || btf_type_is_enum(t))
5724 int btf_distill_func_proto(struct bpf_verifier_log *log,
5726 const struct btf_type *func,
5728 struct btf_func_model *m)
5730 const struct btf_param *args;
5731 const struct btf_type *t;
5736 /* BTF function prototype doesn't match the verifier types.
5737 * Fall back to MAX_BPF_FUNC_REG_ARGS u64 args.
5739 for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
5742 m->nr_args = MAX_BPF_FUNC_REG_ARGS;
5745 args = (const struct btf_param *)(func + 1);
5746 nargs = btf_type_vlen(func);
5747 if (nargs > MAX_BPF_FUNC_ARGS) {
5749 "The function %s has %d arguments. Too many.\n",
5753 ret = __get_type_size(btf, func->type, &t);
5756 "The function %s return type %s is unsupported.\n",
5757 tname, btf_kind_str[BTF_INFO_KIND(t->info)]);
5762 for (i = 0; i < nargs; i++) {
5763 if (i == nargs - 1 && args[i].type == 0) {
5765 "The function %s with variable args is unsupported.\n",
5769 ret = __get_type_size(btf, args[i].type, &t);
5772 "The function %s arg%d type %s is unsupported.\n",
5773 tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]);
5778 "The function %s has malformed void argument.\n",
5782 m->arg_size[i] = ret;
5788 /* Compare BTFs of two functions assuming only scalars and pointers to context.
5789 * t1 points to BTF_KIND_FUNC in btf1
5790 * t2 points to BTF_KIND_FUNC in btf2
5792 * EINVAL - function prototype mismatch
5793 * EFAULT - verifier bug
5794 * 0 - 99% match. The last 1% is validated by the verifier.
5796 static int btf_check_func_type_match(struct bpf_verifier_log *log,
5797 struct btf *btf1, const struct btf_type *t1,
5798 struct btf *btf2, const struct btf_type *t2)
5800 const struct btf_param *args1, *args2;
5801 const char *fn1, *fn2, *s1, *s2;
5802 u32 nargs1, nargs2, i;
5804 fn1 = btf_name_by_offset(btf1, t1->name_off);
5805 fn2 = btf_name_by_offset(btf2, t2->name_off);
5807 if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) {
5808 bpf_log(log, "%s() is not a global function\n", fn1);
5811 if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) {
5812 bpf_log(log, "%s() is not a global function\n", fn2);
5816 t1 = btf_type_by_id(btf1, t1->type);
5817 if (!t1 || !btf_type_is_func_proto(t1))
5819 t2 = btf_type_by_id(btf2, t2->type);
5820 if (!t2 || !btf_type_is_func_proto(t2))
5823 args1 = (const struct btf_param *)(t1 + 1);
5824 nargs1 = btf_type_vlen(t1);
5825 args2 = (const struct btf_param *)(t2 + 1);
5826 nargs2 = btf_type_vlen(t2);
5828 if (nargs1 != nargs2) {
5829 bpf_log(log, "%s() has %d args while %s() has %d args\n",
5830 fn1, nargs1, fn2, nargs2);
5834 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5835 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5836 if (t1->info != t2->info) {
5838 "Return type %s of %s() doesn't match type %s of %s()\n",
5839 btf_type_str(t1), fn1,
5840 btf_type_str(t2), fn2);
5844 for (i = 0; i < nargs1; i++) {
5845 t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL);
5846 t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL);
5848 if (t1->info != t2->info) {
5849 bpf_log(log, "arg%d in %s() is %s while %s() has %s\n",
5850 i, fn1, btf_type_str(t1),
5851 fn2, btf_type_str(t2));
5854 if (btf_type_has_size(t1) && t1->size != t2->size) {
5856 "arg%d in %s() has size %d while %s() has %d\n",
5862 /* global functions are validated with scalars and pointers
5863 * to context only. And only global functions can be replaced.
5864 * Hence type check only those types.
5866 if (btf_type_is_int(t1) || btf_type_is_enum(t1))
5868 if (!btf_type_is_ptr(t1)) {
5870 "arg%d in %s() has unrecognized type\n",
5874 t1 = btf_type_skip_modifiers(btf1, t1->type, NULL);
5875 t2 = btf_type_skip_modifiers(btf2, t2->type, NULL);
5876 if (!btf_type_is_struct(t1)) {
5878 "arg%d in %s() is not a pointer to context\n",
5882 if (!btf_type_is_struct(t2)) {
5884 "arg%d in %s() is not a pointer to context\n",
5888 /* This is an optional check to make program writing easier.
5889 * Compare names of structs and report an error to the user.
5890 * btf_prepare_func_args() already checked that t2 struct
5891 * is a context type. btf_prepare_func_args() will check
5892 * later that t1 struct is a context type as well.
5894 s1 = btf_name_by_offset(btf1, t1->name_off);
5895 s2 = btf_name_by_offset(btf2, t2->name_off);
5896 if (strcmp(s1, s2)) {
5898 "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n",
5899 i, fn1, s1, fn2, s2);
5906 /* Compare BTFs of given program with BTF of target program */
5907 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
5908 struct btf *btf2, const struct btf_type *t2)
5910 struct btf *btf1 = prog->aux->btf;
5911 const struct btf_type *t1;
5914 if (!prog->aux->func_info) {
5915 bpf_log(log, "Program extension requires BTF\n");
5919 btf_id = prog->aux->func_info[0].type_id;
5923 t1 = btf_type_by_id(btf1, btf_id);
5924 if (!t1 || !btf_type_is_func(t1))
5927 return btf_check_func_type_match(log, btf1, t1, btf2, t2);
5930 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
5932 [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
5933 [PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
5934 [PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
5938 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
5939 static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
5940 const struct btf *btf,
5941 const struct btf_type *t, int rec)
5943 const struct btf_type *member_type;
5944 const struct btf_member *member;
5947 if (!btf_type_is_struct(t))
5950 for_each_member(i, t, member) {
5951 const struct btf_array *array;
5953 member_type = btf_type_skip_modifiers(btf, member->type, NULL);
5954 if (btf_type_is_struct(member_type)) {
5956 bpf_log(log, "max struct nesting depth exceeded\n");
5959 if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
5963 if (btf_type_is_array(member_type)) {
5964 array = btf_type_array(member_type);
5967 member_type = btf_type_skip_modifiers(btf, array->type, NULL);
5968 if (!btf_type_is_scalar(member_type))
5972 if (!btf_type_is_scalar(member_type))
5978 static bool is_kfunc_arg_mem_size(const struct btf *btf,
5979 const struct btf_param *arg,
5980 const struct bpf_reg_state *reg)
5982 int len, sfx_len = sizeof("__sz") - 1;
5983 const struct btf_type *t;
5984 const char *param_name;
5986 t = btf_type_skip_modifiers(btf, arg->type, NULL);
5987 if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
5990 /* In the future, this can be ported to use BTF tagging */
5991 param_name = btf_name_by_offset(btf, arg->name_off);
5992 if (str_is_empty(param_name))
5994 len = strlen(param_name);
5997 param_name += len - sfx_len;
5998 if (strncmp(param_name, "__sz", sfx_len))
6004 static int btf_check_func_arg_match(struct bpf_verifier_env *env,
6005 const struct btf *btf, u32 func_id,
6006 struct bpf_reg_state *regs,
6009 struct bpf_verifier_log *log = &env->log;
6010 u32 i, nargs, ref_id, ref_obj_id = 0;
6011 bool is_kfunc = btf_is_kernel(btf);
6012 const char *func_name, *ref_tname;
6013 const struct btf_type *t, *ref_t;
6014 const struct btf_param *args;
6015 int ref_regno = 0, ret;
6018 t = btf_type_by_id(btf, func_id);
6019 if (!t || !btf_type_is_func(t)) {
6020 /* These checks were already done by the verifier while loading
6021 * struct bpf_func_info or in add_kfunc_call().
6023 bpf_log(log, "BTF of func_id %u doesn't point to KIND_FUNC\n",
6027 func_name = btf_name_by_offset(btf, t->name_off);
6029 t = btf_type_by_id(btf, t->type);
6030 if (!t || !btf_type_is_func_proto(t)) {
6031 bpf_log(log, "Invalid BTF of func %s\n", func_name);
6034 args = (const struct btf_param *)(t + 1);
6035 nargs = btf_type_vlen(t);
6036 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6037 bpf_log(log, "Function %s has %d > %d args\n", func_name, nargs,
6038 MAX_BPF_FUNC_REG_ARGS);
6042 /* Only kfunc can be release func */
6044 rel = btf_kfunc_id_set_contains(btf, resolve_prog_type(env->prog),
6045 BTF_KFUNC_TYPE_RELEASE, func_id);
6046 /* check that BTF function arguments match actual types that the
6049 for (i = 0; i < nargs; i++) {
6051 struct bpf_reg_state *reg = ®s[regno];
6053 t = btf_type_skip_modifiers(btf, args[i].type, NULL);
6054 if (btf_type_is_scalar(t)) {
6055 if (reg->type == SCALAR_VALUE)
6057 bpf_log(log, "R%d is not a scalar\n", regno);
6061 if (!btf_type_is_ptr(t)) {
6062 bpf_log(log, "Unrecognized arg#%d type %s\n",
6063 i, btf_type_str(t));
6067 ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
6068 ref_tname = btf_name_by_offset(btf, ref_t->name_off);
6070 ret = check_func_arg_reg_off(env, reg, regno, ARG_DONTCARE, rel);
6074 if (btf_get_prog_ctx_type(log, btf, t,
6075 env->prog->type, i)) {
6076 /* If function expects ctx type in BTF check that caller
6077 * is passing PTR_TO_CTX.
6079 if (reg->type != PTR_TO_CTX) {
6081 "arg#%d expected pointer to ctx, but got %s\n",
6082 i, btf_type_str(t));
6085 } else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
6086 (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
6087 const struct btf_type *reg_ref_t;
6088 const struct btf *reg_btf;
6089 const char *reg_ref_tname;
6092 if (!btf_type_is_struct(ref_t)) {
6093 bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
6094 func_name, i, btf_type_str(ref_t),
6099 if (reg->type == PTR_TO_BTF_ID) {
6101 reg_ref_id = reg->btf_id;
6102 /* Ensure only one argument is referenced
6103 * PTR_TO_BTF_ID, check_func_arg_reg_off relies
6104 * on only one referenced register being allowed
6107 if (reg->ref_obj_id) {
6109 bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
6110 regno, reg->ref_obj_id, ref_obj_id);
6114 ref_obj_id = reg->ref_obj_id;
6117 reg_btf = btf_vmlinux;
6118 reg_ref_id = *reg2btf_ids[base_type(reg->type)];
6121 reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
6123 reg_ref_tname = btf_name_by_offset(reg_btf,
6124 reg_ref_t->name_off);
6125 if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
6126 reg->off, btf, ref_id)) {
6127 bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
6129 btf_type_str(ref_t), ref_tname,
6130 regno, btf_type_str(reg_ref_t),
6134 } else if (ptr_to_mem_ok) {
6135 const struct btf_type *resolve_ret;
6139 bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], ®s[regno + 1]);
6141 /* Permit pointer to mem, but only when argument
6142 * type is pointer to scalar, or struct composed
6143 * (recursively) of scalars.
6144 * When arg_mem_size is true, the pointer can be
6147 if (!btf_type_is_scalar(ref_t) &&
6148 !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
6149 (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
6151 "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
6152 i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
6156 /* Check for mem, len pair */
6158 if (check_kfunc_mem_size_reg(env, ®s[regno + 1], regno + 1)) {
6159 bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
6168 resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
6169 if (IS_ERR(resolve_ret)) {
6171 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6172 i, btf_type_str(ref_t), ref_tname,
6173 PTR_ERR(resolve_ret));
6177 if (check_mem_reg(env, reg, regno, type_size))
6180 bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
6181 is_kfunc ? "kernel " : "", func_name, func_id);
6186 /* Either both are set, or neither */
6187 WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
6188 /* We already made sure ref_obj_id is set only for one argument. We do
6189 * allow (!rel && ref_obj_id), so that passing such referenced
6190 * PTR_TO_BTF_ID to other kfuncs works. Note that rel is only true when
6193 if (rel && !ref_obj_id) {
6194 bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
6198 /* returns argument register number > 0 in case of reference release kfunc */
6199 return rel ? ref_regno : 0;
6202 /* Compare BTF of a function with given bpf_reg_state.
6204 * EFAULT - there is a verifier bug. Abort verification.
6205 * EINVAL - there is a type mismatch or BTF is not available.
6206 * 0 - BTF matches with what bpf_reg_state expects.
6207 * Only PTR_TO_CTX and SCALAR_VALUE states are recognized.
6209 int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
6210 struct bpf_reg_state *regs)
6212 struct bpf_prog *prog = env->prog;
6213 struct btf *btf = prog->aux->btf;
6218 if (!prog->aux->func_info)
6221 btf_id = prog->aux->func_info[subprog].type_id;
6225 if (prog->aux->func_info_aux[subprog].unreliable)
6228 is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
6229 err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global);
6231 /* Compiler optimizations can remove arguments from static functions
6232 * or mismatched type can be passed into a global function.
6233 * In such cases mark the function as unreliable from BTF point of view.
6236 prog->aux->func_info_aux[subprog].unreliable = true;
6240 int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
6241 const struct btf *btf, u32 func_id,
6242 struct bpf_reg_state *regs)
6244 return btf_check_func_arg_match(env, btf, func_id, regs, true);
6247 /* Convert BTF of a function into bpf_reg_state if possible
6249 * EFAULT - there is a verifier bug. Abort verification.
6250 * EINVAL - cannot convert BTF.
6251 * 0 - Successfully converted BTF into bpf_reg_state
6252 * (either PTR_TO_CTX or SCALAR_VALUE).
6254 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
6255 struct bpf_reg_state *regs)
6257 struct bpf_verifier_log *log = &env->log;
6258 struct bpf_prog *prog = env->prog;
6259 enum bpf_prog_type prog_type = prog->type;
6260 struct btf *btf = prog->aux->btf;
6261 const struct btf_param *args;
6262 const struct btf_type *t, *ref_t;
6263 u32 i, nargs, btf_id;
6266 if (!prog->aux->func_info ||
6267 prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) {
6268 bpf_log(log, "Verifier bug\n");
6272 btf_id = prog->aux->func_info[subprog].type_id;
6274 bpf_log(log, "Global functions need valid BTF\n");
6278 t = btf_type_by_id(btf, btf_id);
6279 if (!t || !btf_type_is_func(t)) {
6280 /* These checks were already done by the verifier while loading
6281 * struct bpf_func_info
6283 bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n",
6287 tname = btf_name_by_offset(btf, t->name_off);
6289 if (log->level & BPF_LOG_LEVEL)
6290 bpf_log(log, "Validating %s() func#%d...\n",
6293 if (prog->aux->func_info_aux[subprog].unreliable) {
6294 bpf_log(log, "Verifier bug in function %s()\n", tname);
6297 if (prog_type == BPF_PROG_TYPE_EXT)
6298 prog_type = prog->aux->dst_prog->type;
6300 t = btf_type_by_id(btf, t->type);
6301 if (!t || !btf_type_is_func_proto(t)) {
6302 bpf_log(log, "Invalid type of function %s()\n", tname);
6305 args = (const struct btf_param *)(t + 1);
6306 nargs = btf_type_vlen(t);
6307 if (nargs > MAX_BPF_FUNC_REG_ARGS) {
6308 bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n",
6309 tname, nargs, MAX_BPF_FUNC_REG_ARGS);
6312 /* check that function returns int */
6313 t = btf_type_by_id(btf, t->type);
6314 while (btf_type_is_modifier(t))
6315 t = btf_type_by_id(btf, t->type);
6316 if (!btf_type_is_int(t) && !btf_type_is_enum(t)) {
6318 "Global function %s() doesn't return scalar. Only those are supported.\n",
6322 /* Convert BTF function arguments into verifier types.
6323 * Only PTR_TO_CTX and SCALAR are supported atm.
6325 for (i = 0; i < nargs; i++) {
6326 struct bpf_reg_state *reg = ®s[i + 1];
6328 t = btf_type_by_id(btf, args[i].type);
6329 while (btf_type_is_modifier(t))
6330 t = btf_type_by_id(btf, t->type);
6331 if (btf_type_is_int(t) || btf_type_is_enum(t)) {
6332 reg->type = SCALAR_VALUE;
6335 if (btf_type_is_ptr(t)) {
6336 if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
6337 reg->type = PTR_TO_CTX;
6341 t = btf_type_skip_modifiers(btf, t->type, NULL);
6343 ref_t = btf_resolve_size(btf, t, ®->mem_size);
6344 if (IS_ERR(ref_t)) {
6346 "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
6347 i, btf_type_str(t), btf_name_by_offset(btf, t->name_off),
6352 reg->type = PTR_TO_MEM | PTR_MAYBE_NULL;
6353 reg->id = ++env->id_gen;
6357 bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n",
6358 i, btf_kind_str[BTF_INFO_KIND(t->info)], tname);
6364 static void btf_type_show(const struct btf *btf, u32 type_id, void *obj,
6365 struct btf_show *show)
6367 const struct btf_type *t = btf_type_by_id(btf, type_id);
6370 memset(&show->state, 0, sizeof(show->state));
6371 memset(&show->obj, 0, sizeof(show->obj));
6373 btf_type_ops(t)->show(btf, t, type_id, obj, 0, show);
6376 static void btf_seq_show(struct btf_show *show, const char *fmt,
6379 seq_vprintf((struct seq_file *)show->target, fmt, args);
6382 int btf_type_seq_show_flags(const struct btf *btf, u32 type_id,
6383 void *obj, struct seq_file *m, u64 flags)
6385 struct btf_show sseq;
6388 sseq.showfn = btf_seq_show;
6391 btf_type_show(btf, type_id, obj, &sseq);
6393 return sseq.state.status;
6396 void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj,
6399 (void) btf_type_seq_show_flags(btf, type_id, obj, m,
6400 BTF_SHOW_NONAME | BTF_SHOW_COMPACT |
6401 BTF_SHOW_ZERO | BTF_SHOW_UNSAFE);
6404 struct btf_show_snprintf {
6405 struct btf_show show;
6406 int len_left; /* space left in string */
6407 int len; /* length we would have written */
6410 static void btf_snprintf_show(struct btf_show *show, const char *fmt,
6413 struct btf_show_snprintf *ssnprintf = (struct btf_show_snprintf *)show;
6416 len = vsnprintf(show->target, ssnprintf->len_left, fmt, args);
6419 ssnprintf->len_left = 0;
6420 ssnprintf->len = len;
6421 } else if (len > ssnprintf->len_left) {
6422 /* no space, drive on to get length we would have written */
6423 ssnprintf->len_left = 0;
6424 ssnprintf->len += len;
6426 ssnprintf->len_left -= len;
6427 ssnprintf->len += len;
6428 show->target += len;
6432 int btf_type_snprintf_show(const struct btf *btf, u32 type_id, void *obj,
6433 char *buf, int len, u64 flags)
6435 struct btf_show_snprintf ssnprintf;
6437 ssnprintf.show.target = buf;
6438 ssnprintf.show.flags = flags;
6439 ssnprintf.show.showfn = btf_snprintf_show;
6440 ssnprintf.len_left = len;
6443 btf_type_show(btf, type_id, obj, (struct btf_show *)&ssnprintf);
6445 /* If we encountered an error, return it. */
6446 if (ssnprintf.show.state.status)
6447 return ssnprintf.show.state.status;
6449 /* Otherwise return length we would have written */
6450 return ssnprintf.len;
6453 #ifdef CONFIG_PROC_FS
6454 static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp)
6456 const struct btf *btf = filp->private_data;
6458 seq_printf(m, "btf_id:\t%u\n", btf->id);
6462 static int btf_release(struct inode *inode, struct file *filp)
6464 btf_put(filp->private_data);
6468 const struct file_operations btf_fops = {
6469 #ifdef CONFIG_PROC_FS
6470 .show_fdinfo = bpf_btf_show_fdinfo,
6472 .release = btf_release,
6475 static int __btf_new_fd(struct btf *btf)
6477 return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC);
6480 int btf_new_fd(const union bpf_attr *attr, bpfptr_t uattr)
6485 btf = btf_parse(make_bpfptr(attr->btf, uattr.is_kernel),
6486 attr->btf_size, attr->btf_log_level,
6487 u64_to_user_ptr(attr->btf_log_buf),
6488 attr->btf_log_size);
6490 return PTR_ERR(btf);
6492 ret = btf_alloc_id(btf);
6499 * The BTF ID is published to the userspace.
6500 * All BTF free must go through call_rcu() from
6501 * now on (i.e. free by calling btf_put()).
6504 ret = __btf_new_fd(btf);
6511 struct btf *btf_get_by_fd(int fd)
6519 return ERR_PTR(-EBADF);
6521 if (f.file->f_op != &btf_fops) {
6523 return ERR_PTR(-EINVAL);
6526 btf = f.file->private_data;
6527 refcount_inc(&btf->refcnt);
6533 int btf_get_info_by_fd(const struct btf *btf,
6534 const union bpf_attr *attr,
6535 union bpf_attr __user *uattr)
6537 struct bpf_btf_info __user *uinfo;
6538 struct bpf_btf_info info;
6539 u32 info_copy, btf_copy;
6542 u32 uinfo_len, uname_len, name_len;
6545 uinfo = u64_to_user_ptr(attr->info.info);
6546 uinfo_len = attr->info.info_len;
6548 info_copy = min_t(u32, uinfo_len, sizeof(info));
6549 memset(&info, 0, sizeof(info));
6550 if (copy_from_user(&info, uinfo, info_copy))
6554 ubtf = u64_to_user_ptr(info.btf);
6555 btf_copy = min_t(u32, btf->data_size, info.btf_size);
6556 if (copy_to_user(ubtf, btf->data, btf_copy))
6558 info.btf_size = btf->data_size;
6560 info.kernel_btf = btf->kernel_btf;
6562 uname = u64_to_user_ptr(info.name);
6563 uname_len = info.name_len;
6564 if (!uname ^ !uname_len)
6567 name_len = strlen(btf->name);
6568 info.name_len = name_len;
6571 if (uname_len >= name_len + 1) {
6572 if (copy_to_user(uname, btf->name, name_len + 1))
6577 if (copy_to_user(uname, btf->name, uname_len - 1))
6579 if (put_user(zero, uname + uname_len - 1))
6581 /* let user-space know about too short buffer */
6586 if (copy_to_user(uinfo, &info, info_copy) ||
6587 put_user(info_copy, &uattr->info.info_len))
6593 int btf_get_fd_by_id(u32 id)
6599 btf = idr_find(&btf_idr, id);
6600 if (!btf || !refcount_inc_not_zero(&btf->refcnt))
6601 btf = ERR_PTR(-ENOENT);
6605 return PTR_ERR(btf);
6607 fd = __btf_new_fd(btf);
6614 u32 btf_obj_id(const struct btf *btf)
6619 bool btf_is_kernel(const struct btf *btf)
6621 return btf->kernel_btf;
6624 bool btf_is_module(const struct btf *btf)
6626 return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
6629 static int btf_id_cmp_func(const void *a, const void *b)
6631 const int *pa = a, *pb = b;
6636 bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
6638 return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
6642 BTF_MODULE_F_LIVE = (1 << 0),
6645 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6647 struct list_head list;
6648 struct module *module;
6650 struct bin_attribute *sysfs_attr;
6654 static LIST_HEAD(btf_modules);
6655 static DEFINE_MUTEX(btf_module_mutex);
6658 btf_module_read(struct file *file, struct kobject *kobj,
6659 struct bin_attribute *bin_attr,
6660 char *buf, loff_t off, size_t len)
6662 const struct btf *btf = bin_attr->private;
6664 memcpy(buf, btf->data + off, len);
6668 static void purge_cand_cache(struct btf *btf);
6670 static int btf_module_notify(struct notifier_block *nb, unsigned long op,
6673 struct btf_module *btf_mod, *tmp;
6674 struct module *mod = module;
6678 if (mod->btf_data_size == 0 ||
6679 (op != MODULE_STATE_COMING && op != MODULE_STATE_LIVE &&
6680 op != MODULE_STATE_GOING))
6684 case MODULE_STATE_COMING:
6685 btf_mod = kzalloc(sizeof(*btf_mod), GFP_KERNEL);
6690 btf = btf_parse_module(mod->name, mod->btf_data, mod->btf_data_size);
6692 pr_warn("failed to validate module [%s] BTF: %ld\n",
6693 mod->name, PTR_ERR(btf));
6695 if (!IS_ENABLED(CONFIG_MODULE_ALLOW_BTF_MISMATCH))
6699 err = btf_alloc_id(btf);
6706 purge_cand_cache(NULL);
6707 mutex_lock(&btf_module_mutex);
6708 btf_mod->module = module;
6710 list_add(&btf_mod->list, &btf_modules);
6711 mutex_unlock(&btf_module_mutex);
6713 if (IS_ENABLED(CONFIG_SYSFS)) {
6714 struct bin_attribute *attr;
6716 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
6720 sysfs_bin_attr_init(attr);
6721 attr->attr.name = btf->name;
6722 attr->attr.mode = 0444;
6723 attr->size = btf->data_size;
6724 attr->private = btf;
6725 attr->read = btf_module_read;
6727 err = sysfs_create_bin_file(btf_kobj, attr);
6729 pr_warn("failed to register module [%s] BTF in sysfs: %d\n",
6736 btf_mod->sysfs_attr = attr;
6740 case MODULE_STATE_LIVE:
6741 mutex_lock(&btf_module_mutex);
6742 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6743 if (btf_mod->module != module)
6746 btf_mod->flags |= BTF_MODULE_F_LIVE;
6749 mutex_unlock(&btf_module_mutex);
6751 case MODULE_STATE_GOING:
6752 mutex_lock(&btf_module_mutex);
6753 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6754 if (btf_mod->module != module)
6757 list_del(&btf_mod->list);
6758 if (btf_mod->sysfs_attr)
6759 sysfs_remove_bin_file(btf_kobj, btf_mod->sysfs_attr);
6760 purge_cand_cache(btf_mod->btf);
6761 btf_put(btf_mod->btf);
6762 kfree(btf_mod->sysfs_attr);
6766 mutex_unlock(&btf_module_mutex);
6770 return notifier_from_errno(err);
6773 static struct notifier_block btf_module_nb = {
6774 .notifier_call = btf_module_notify,
6777 static int __init btf_module_init(void)
6779 register_module_notifier(&btf_module_nb);
6783 fs_initcall(btf_module_init);
6784 #endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
6786 struct module *btf_try_get_module(const struct btf *btf)
6788 struct module *res = NULL;
6789 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6790 struct btf_module *btf_mod, *tmp;
6792 mutex_lock(&btf_module_mutex);
6793 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6794 if (btf_mod->btf != btf)
6797 /* We must only consider module whose __init routine has
6798 * finished, hence we must check for BTF_MODULE_F_LIVE flag,
6799 * which is set from the notifier callback for
6800 * MODULE_STATE_LIVE.
6802 if ((btf_mod->flags & BTF_MODULE_F_LIVE) && try_module_get(btf_mod->module))
6803 res = btf_mod->module;
6807 mutex_unlock(&btf_module_mutex);
6813 /* Returns struct btf corresponding to the struct module.
6814 * This function can return NULL or ERR_PTR.
6816 static struct btf *btf_get_module_btf(const struct module *module)
6818 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6819 struct btf_module *btf_mod, *tmp;
6821 struct btf *btf = NULL;
6824 btf = bpf_get_btf_vmlinux();
6825 if (!IS_ERR_OR_NULL(btf))
6830 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
6831 mutex_lock(&btf_module_mutex);
6832 list_for_each_entry_safe(btf_mod, tmp, &btf_modules, list) {
6833 if (btf_mod->module != module)
6836 btf_get(btf_mod->btf);
6840 mutex_unlock(&btf_module_mutex);
6846 BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags)
6848 struct btf *btf = NULL;
6855 if (name_sz <= 1 || name[name_sz - 1])
6858 ret = bpf_find_btf_id(name, kind, &btf);
6859 if (ret > 0 && btf_is_module(btf)) {
6860 btf_obj_fd = __btf_new_fd(btf);
6861 if (btf_obj_fd < 0) {
6865 return ret | (((u64)btf_obj_fd) << 32);
6872 const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
6873 .func = bpf_btf_find_by_name_kind,
6875 .ret_type = RET_INTEGER,
6876 .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
6877 .arg2_type = ARG_CONST_SIZE,
6878 .arg3_type = ARG_ANYTHING,
6879 .arg4_type = ARG_ANYTHING,
6882 BTF_ID_LIST_GLOBAL(btf_tracing_ids, MAX_BTF_TRACING_TYPE)
6883 #define BTF_TRACING_TYPE(name, type) BTF_ID(struct, type)
6884 BTF_TRACING_TYPE_xxx
6885 #undef BTF_TRACING_TYPE
6887 /* Kernel Function (kfunc) BTF ID set registration API */
6889 static int __btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
6890 enum btf_kfunc_type type,
6891 struct btf_id_set *add_set, bool vmlinux_set)
6893 struct btf_kfunc_set_tab *tab;
6894 struct btf_id_set *set;
6898 if (hook >= BTF_KFUNC_HOOK_MAX || type >= BTF_KFUNC_TYPE_MAX) {
6906 tab = btf->kfunc_set_tab;
6908 tab = kzalloc(sizeof(*tab), GFP_KERNEL | __GFP_NOWARN);
6911 btf->kfunc_set_tab = tab;
6914 set = tab->sets[hook][type];
6915 /* Warn when register_btf_kfunc_id_set is called twice for the same hook
6918 if (WARN_ON_ONCE(set && !vmlinux_set)) {
6923 /* We don't need to allocate, concatenate, and sort module sets, because
6924 * only one is allowed per hook. Hence, we can directly assign the
6925 * pointer and return.
6928 tab->sets[hook][type] = add_set;
6932 /* In case of vmlinux sets, there may be more than one set being
6933 * registered per hook. To create a unified set, we allocate a new set
6934 * and concatenate all individual sets being registered. While each set
6935 * is individually sorted, they may become unsorted when concatenated,
6936 * hence re-sorting the final set again is required to make binary
6937 * searching the set using btf_id_set_contains function work.
6939 set_cnt = set ? set->cnt : 0;
6941 if (set_cnt > U32_MAX - add_set->cnt) {
6946 if (set_cnt + add_set->cnt > BTF_KFUNC_SET_MAX_CNT) {
6952 set = krealloc(tab->sets[hook][type],
6953 offsetof(struct btf_id_set, ids[set_cnt + add_set->cnt]),
6954 GFP_KERNEL | __GFP_NOWARN);
6960 /* For newly allocated set, initialize set->cnt to 0 */
6961 if (!tab->sets[hook][type])
6963 tab->sets[hook][type] = set;
6965 /* Concatenate the two sets */
6966 memcpy(set->ids + set->cnt, add_set->ids, add_set->cnt * sizeof(set->ids[0]));
6967 set->cnt += add_set->cnt;
6969 sort(set->ids, set->cnt, sizeof(set->ids[0]), btf_id_cmp_func, NULL);
6973 btf_free_kfunc_set_tab(btf);
6977 static int btf_populate_kfunc_set(struct btf *btf, enum btf_kfunc_hook hook,
6978 const struct btf_kfunc_id_set *kset)
6980 bool vmlinux_set = !btf_is_module(btf);
6983 for (type = 0; type < ARRAY_SIZE(kset->sets); type++) {
6984 if (!kset->sets[type])
6987 ret = __btf_populate_kfunc_set(btf, hook, type, kset->sets[type], vmlinux_set);
6994 static bool __btf_kfunc_id_set_contains(const struct btf *btf,
6995 enum btf_kfunc_hook hook,
6996 enum btf_kfunc_type type,
6999 struct btf_id_set *set;
7001 if (hook >= BTF_KFUNC_HOOK_MAX || type >= BTF_KFUNC_TYPE_MAX)
7003 if (!btf->kfunc_set_tab)
7005 set = btf->kfunc_set_tab->sets[hook][type];
7008 return btf_id_set_contains(set, kfunc_btf_id);
7011 static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
7013 switch (prog_type) {
7014 case BPF_PROG_TYPE_XDP:
7015 return BTF_KFUNC_HOOK_XDP;
7016 case BPF_PROG_TYPE_SCHED_CLS:
7017 return BTF_KFUNC_HOOK_TC;
7018 case BPF_PROG_TYPE_STRUCT_OPS:
7019 return BTF_KFUNC_HOOK_STRUCT_OPS;
7021 return BTF_KFUNC_HOOK_MAX;
7026 * Reference to the module (obtained using btf_try_get_module) corresponding to
7027 * the struct btf *MUST* be held when calling this function from verifier
7028 * context. This is usually true as we stash references in prog's kfunc_btf_tab;
7029 * keeping the reference for the duration of the call provides the necessary
7030 * protection for looking up a well-formed btf->kfunc_set_tab.
7032 bool btf_kfunc_id_set_contains(const struct btf *btf,
7033 enum bpf_prog_type prog_type,
7034 enum btf_kfunc_type type, u32 kfunc_btf_id)
7036 enum btf_kfunc_hook hook;
7038 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7039 return __btf_kfunc_id_set_contains(btf, hook, type, kfunc_btf_id);
7042 /* This function must be invoked only from initcalls/module init functions */
7043 int register_btf_kfunc_id_set(enum bpf_prog_type prog_type,
7044 const struct btf_kfunc_id_set *kset)
7046 enum btf_kfunc_hook hook;
7050 btf = btf_get_module_btf(kset->owner);
7052 if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
7053 pr_err("missing vmlinux BTF, cannot register kfuncs\n");
7056 if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) {
7057 pr_err("missing module BTF, cannot register kfuncs\n");
7063 return PTR_ERR(btf);
7065 hook = bpf_prog_type_to_kfunc_hook(prog_type);
7066 ret = btf_populate_kfunc_set(btf, hook, kset);
7070 EXPORT_SYMBOL_GPL(register_btf_kfunc_id_set);
7072 #define MAX_TYPES_ARE_COMPAT_DEPTH 2
7075 int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
7076 const struct btf *targ_btf, __u32 targ_id,
7079 const struct btf_type *local_type, *targ_type;
7080 int depth = 32; /* max recursion depth */
7082 /* caller made sure that names match (ignoring flavor suffix) */
7083 local_type = btf_type_by_id(local_btf, local_id);
7084 targ_type = btf_type_by_id(targ_btf, targ_id);
7085 if (btf_kind(local_type) != btf_kind(targ_type))
7093 local_type = btf_type_skip_modifiers(local_btf, local_id, &local_id);
7094 targ_type = btf_type_skip_modifiers(targ_btf, targ_id, &targ_id);
7095 if (!local_type || !targ_type)
7098 if (btf_kind(local_type) != btf_kind(targ_type))
7101 switch (btf_kind(local_type)) {
7103 case BTF_KIND_STRUCT:
7104 case BTF_KIND_UNION:
7109 /* just reject deprecated bitfield-like integers; all other
7110 * integers are by default compatible between each other
7112 return btf_int_offset(local_type) == 0 && btf_int_offset(targ_type) == 0;
7114 local_id = local_type->type;
7115 targ_id = targ_type->type;
7117 case BTF_KIND_ARRAY:
7118 local_id = btf_array(local_type)->type;
7119 targ_id = btf_array(targ_type)->type;
7121 case BTF_KIND_FUNC_PROTO: {
7122 struct btf_param *local_p = btf_params(local_type);
7123 struct btf_param *targ_p = btf_params(targ_type);
7124 __u16 local_vlen = btf_vlen(local_type);
7125 __u16 targ_vlen = btf_vlen(targ_type);
7128 if (local_vlen != targ_vlen)
7131 for (i = 0; i < local_vlen; i++, local_p++, targ_p++) {
7135 btf_type_skip_modifiers(local_btf, local_p->type, &local_id);
7136 btf_type_skip_modifiers(targ_btf, targ_p->type, &targ_id);
7137 err = __bpf_core_types_are_compat(local_btf, local_id,
7144 /* tail recurse for return type check */
7145 btf_type_skip_modifiers(local_btf, local_type->type, &local_id);
7146 btf_type_skip_modifiers(targ_btf, targ_type->type, &targ_id);
7154 /* Check local and target types for compatibility. This check is used for
7155 * type-based CO-RE relocations and follow slightly different rules than
7156 * field-based relocations. This function assumes that root types were already
7157 * checked for name match. Beyond that initial root-level name check, names
7158 * are completely ignored. Compatibility rules are as follows:
7159 * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but
7160 * kind should match for local and target types (i.e., STRUCT is not
7161 * compatible with UNION);
7162 * - for ENUMs, the size is ignored;
7163 * - for INT, size and signedness are ignored;
7164 * - for ARRAY, dimensionality is ignored, element types are checked for
7165 * compatibility recursively;
7166 * - CONST/VOLATILE/RESTRICT modifiers are ignored;
7167 * - TYPEDEFs/PTRs are compatible if types they pointing to are compatible;
7168 * - FUNC_PROTOs are compatible if they have compatible signature: same
7169 * number of input args and compatible return and argument types.
7170 * These rules are not set in stone and probably will be adjusted as we get
7171 * more experience with using BPF CO-RE relocations.
7173 int bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id,
7174 const struct btf *targ_btf, __u32 targ_id)
7176 return __bpf_core_types_are_compat(local_btf, local_id,
7178 MAX_TYPES_ARE_COMPAT_DEPTH);
7181 static bool bpf_core_is_flavor_sep(const char *s)
7183 /* check X___Y name pattern, where X and Y are not underscores */
7184 return s[0] != '_' && /* X */
7185 s[1] == '_' && s[2] == '_' && s[3] == '_' && /* ___ */
7186 s[4] != '_'; /* Y */
7189 size_t bpf_core_essential_name_len(const char *name)
7191 size_t n = strlen(name);
7194 for (i = n - 5; i >= 0; i--) {
7195 if (bpf_core_is_flavor_sep(name + i))
7201 struct bpf_cand_cache {
7207 const struct btf *btf;
7212 static void bpf_free_cands(struct bpf_cand_cache *cands)
7215 /* empty candidate array was allocated on stack */
7220 static void bpf_free_cands_from_cache(struct bpf_cand_cache *cands)
7226 #define VMLINUX_CAND_CACHE_SIZE 31
7227 static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE];
7229 #define MODULE_CAND_CACHE_SIZE 31
7230 static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE];
7232 static DEFINE_MUTEX(cand_cache_mutex);
7234 static void __print_cand_cache(struct bpf_verifier_log *log,
7235 struct bpf_cand_cache **cache,
7238 struct bpf_cand_cache *cc;
7241 for (i = 0; i < cache_size; i++) {
7245 bpf_log(log, "[%d]%s(", i, cc->name);
7246 for (j = 0; j < cc->cnt; j++) {
7247 bpf_log(log, "%d", cc->cands[j].id);
7248 if (j < cc->cnt - 1)
7251 bpf_log(log, "), ");
7255 static void print_cand_cache(struct bpf_verifier_log *log)
7257 mutex_lock(&cand_cache_mutex);
7258 bpf_log(log, "vmlinux_cand_cache:");
7259 __print_cand_cache(log, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7260 bpf_log(log, "\nmodule_cand_cache:");
7261 __print_cand_cache(log, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7263 mutex_unlock(&cand_cache_mutex);
7266 static u32 hash_cands(struct bpf_cand_cache *cands)
7268 return jhash(cands->name, cands->name_len, 0);
7271 static struct bpf_cand_cache *check_cand_cache(struct bpf_cand_cache *cands,
7272 struct bpf_cand_cache **cache,
7275 struct bpf_cand_cache *cc = cache[hash_cands(cands) % cache_size];
7277 if (cc && cc->name_len == cands->name_len &&
7278 !strncmp(cc->name, cands->name, cands->name_len))
7283 static size_t sizeof_cands(int cnt)
7285 return offsetof(struct bpf_cand_cache, cands[cnt]);
7288 static struct bpf_cand_cache *populate_cand_cache(struct bpf_cand_cache *cands,
7289 struct bpf_cand_cache **cache,
7292 struct bpf_cand_cache **cc = &cache[hash_cands(cands) % cache_size], *new_cands;
7295 bpf_free_cands_from_cache(*cc);
7298 new_cands = kmemdup(cands, sizeof_cands(cands->cnt), GFP_KERNEL);
7300 bpf_free_cands(cands);
7301 return ERR_PTR(-ENOMEM);
7303 /* strdup the name, since it will stay in cache.
7304 * the cands->name points to strings in prog's BTF and the prog can be unloaded.
7306 new_cands->name = kmemdup_nul(cands->name, cands->name_len, GFP_KERNEL);
7307 bpf_free_cands(cands);
7308 if (!new_cands->name) {
7310 return ERR_PTR(-ENOMEM);
7316 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
7317 static void __purge_cand_cache(struct btf *btf, struct bpf_cand_cache **cache,
7320 struct bpf_cand_cache *cc;
7323 for (i = 0; i < cache_size; i++) {
7328 /* when new module is loaded purge all of module_cand_cache,
7329 * since new module might have candidates with the name
7330 * that matches cached cands.
7332 bpf_free_cands_from_cache(cc);
7336 /* when module is unloaded purge cache entries
7337 * that match module's btf
7339 for (j = 0; j < cc->cnt; j++)
7340 if (cc->cands[j].btf == btf) {
7341 bpf_free_cands_from_cache(cc);
7349 static void purge_cand_cache(struct btf *btf)
7351 mutex_lock(&cand_cache_mutex);
7352 __purge_cand_cache(btf, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7353 mutex_unlock(&cand_cache_mutex);
7357 static struct bpf_cand_cache *
7358 bpf_core_add_cands(struct bpf_cand_cache *cands, const struct btf *targ_btf,
7361 struct bpf_cand_cache *new_cands;
7362 const struct btf_type *t;
7363 const char *targ_name;
7364 size_t targ_essent_len;
7367 n = btf_nr_types(targ_btf);
7368 for (i = targ_start_id; i < n; i++) {
7369 t = btf_type_by_id(targ_btf, i);
7370 if (btf_kind(t) != cands->kind)
7373 targ_name = btf_name_by_offset(targ_btf, t->name_off);
7377 /* the resched point is before strncmp to make sure that search
7378 * for non-existing name will have a chance to schedule().
7382 if (strncmp(cands->name, targ_name, cands->name_len) != 0)
7385 targ_essent_len = bpf_core_essential_name_len(targ_name);
7386 if (targ_essent_len != cands->name_len)
7389 /* most of the time there is only one candidate for a given kind+name pair */
7390 new_cands = kmalloc(sizeof_cands(cands->cnt + 1), GFP_KERNEL);
7392 bpf_free_cands(cands);
7393 return ERR_PTR(-ENOMEM);
7396 memcpy(new_cands, cands, sizeof_cands(cands->cnt));
7397 bpf_free_cands(cands);
7399 cands->cands[cands->cnt].btf = targ_btf;
7400 cands->cands[cands->cnt].id = i;
7406 static struct bpf_cand_cache *
7407 bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id)
7409 struct bpf_cand_cache *cands, *cc, local_cand = {};
7410 const struct btf *local_btf = ctx->btf;
7411 const struct btf_type *local_type;
7412 const struct btf *main_btf;
7413 size_t local_essent_len;
7414 struct btf *mod_btf;
7418 main_btf = bpf_get_btf_vmlinux();
7419 if (IS_ERR(main_btf))
7420 return ERR_CAST(main_btf);
7422 return ERR_PTR(-EINVAL);
7424 local_type = btf_type_by_id(local_btf, local_type_id);
7426 return ERR_PTR(-EINVAL);
7428 name = btf_name_by_offset(local_btf, local_type->name_off);
7429 if (str_is_empty(name))
7430 return ERR_PTR(-EINVAL);
7431 local_essent_len = bpf_core_essential_name_len(name);
7433 cands = &local_cand;
7435 cands->kind = btf_kind(local_type);
7436 cands->name_len = local_essent_len;
7438 cc = check_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7439 /* cands is a pointer to stack here */
7446 /* Attempt to find target candidates in vmlinux BTF first */
7447 cands = bpf_core_add_cands(cands, main_btf, 1);
7449 return ERR_CAST(cands);
7451 /* cands is a pointer to kmalloced memory here if cands->cnt > 0 */
7453 /* populate cache even when cands->cnt == 0 */
7454 cc = populate_cand_cache(cands, vmlinux_cand_cache, VMLINUX_CAND_CACHE_SIZE);
7456 return ERR_CAST(cc);
7458 /* if vmlinux BTF has any candidate, don't go for module BTFs */
7463 /* cands is a pointer to stack here and cands->cnt == 0 */
7464 cc = check_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7466 /* if cache has it return it even if cc->cnt == 0 */
7469 /* If candidate is not found in vmlinux's BTF then search in module's BTFs */
7470 spin_lock_bh(&btf_idr_lock);
7471 idr_for_each_entry(&btf_idr, mod_btf, id) {
7472 if (!btf_is_module(mod_btf))
7474 /* linear search could be slow hence unlock/lock
7475 * the IDR to avoiding holding it for too long
7478 spin_unlock_bh(&btf_idr_lock);
7479 cands = bpf_core_add_cands(cands, mod_btf, btf_nr_types(main_btf));
7480 if (IS_ERR(cands)) {
7482 return ERR_CAST(cands);
7484 spin_lock_bh(&btf_idr_lock);
7487 spin_unlock_bh(&btf_idr_lock);
7488 /* cands is a pointer to kmalloced memory here if cands->cnt > 0
7489 * or pointer to stack if cands->cnd == 0.
7490 * Copy it into the cache even when cands->cnt == 0 and
7491 * return the result.
7493 return populate_cand_cache(cands, module_cand_cache, MODULE_CAND_CACHE_SIZE);
7496 int bpf_core_apply(struct bpf_core_ctx *ctx, const struct bpf_core_relo *relo,
7497 int relo_idx, void *insn)
7499 bool need_cands = relo->kind != BPF_CORE_TYPE_ID_LOCAL;
7500 struct bpf_core_cand_list cands = {};
7501 struct bpf_core_relo_res targ_res;
7502 struct bpf_core_spec *specs;
7505 /* ~4k of temp memory necessary to convert LLVM spec like "0:1:0:5"
7506 * into arrays of btf_ids of struct fields and array indices.
7508 specs = kcalloc(3, sizeof(*specs), GFP_KERNEL);
7513 struct bpf_cand_cache *cc;
7516 mutex_lock(&cand_cache_mutex);
7517 cc = bpf_core_find_cands(ctx, relo->type_id);
7519 bpf_log(ctx->log, "target candidate search failed for %d\n",
7525 cands.cands = kcalloc(cc->cnt, sizeof(*cands.cands), GFP_KERNEL);
7531 for (i = 0; i < cc->cnt; i++) {
7533 "CO-RE relocating %s %s: found target candidate [%d]\n",
7534 btf_kind_str[cc->kind], cc->name, cc->cands[i].id);
7535 cands.cands[i].btf = cc->cands[i].btf;
7536 cands.cands[i].id = cc->cands[i].id;
7538 cands.len = cc->cnt;
7539 /* cand_cache_mutex needs to span the cache lookup and
7540 * copy of btf pointer into bpf_core_cand_list,
7541 * since module can be unloaded while bpf_core_calc_relo_insn
7542 * is working with module's btf.
7546 err = bpf_core_calc_relo_insn((void *)ctx->log, relo, relo_idx, ctx->btf, &cands, specs,
7551 err = bpf_core_patch_insn((void *)ctx->log, insn, relo->insn_off / 8, relo, relo_idx,
7558 mutex_unlock(&cand_cache_mutex);
7559 if (ctx->log->level & BPF_LOG_LEVEL2)
7560 print_cand_cache(ctx->log);