/* SPDX-License-Identifier: GPL-2.0 */ /* Copyright (c) 2018 Facebook */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* BTF (BPF Type Format) is the meta data format which describes * the data types of BPF program/map. Hence, it basically focus * on the C programming language which the modern BPF is primary * using. * * ELF Section: * ~~~~~~~~~~~ * The BTF data is stored under the ".BTF" ELF section * * struct btf_type: * ~~~~~~~~~~~~~~~ * Each 'struct btf_type' object describes a C data type. * Depending on the type it is describing, a 'struct btf_type' * object may be followed by more data. F.e. * To describe an array, 'struct btf_type' is followed by * 'struct btf_array'. * * 'struct btf_type' and any extra data following it are * 4 bytes aligned. * * Type section: * ~~~~~~~~~~~~~ * The BTF type section contains a list of 'struct btf_type' objects. * Each one describes a C type. Recall from the above section * that a 'struct btf_type' object could be immediately followed by extra * data in order to desribe some particular C types. * * type_id: * ~~~~~~~ * Each btf_type object is identified by a type_id. The type_id * is implicitly implied by the location of the btf_type object in * the BTF type section. The first one has type_id 1. The second * one has type_id 2...etc. Hence, an earlier btf_type has * a smaller type_id. * * A btf_type object may refer to another btf_type object by using * type_id (i.e. the "type" in the "struct btf_type"). * * NOTE that we cannot assume any reference-order. * A btf_type object can refer to an earlier btf_type object * but it can also refer to a later btf_type object. * * For example, to describe "const void *". A btf_type * object describing "const" may refer to another btf_type * object describing "void *". This type-reference is done * by specifying type_id: * * [1] CONST (anon) type_id=2 * [2] PTR (anon) type_id=0 * * The above is the btf_verifier debug log: * - Each line started with "[?]" is a btf_type object * - [?] is the type_id of the btf_type object. * - CONST/PTR is the BTF_KIND_XXX * - "(anon)" is the name of the type. It just * happens that CONST and PTR has no name. * - type_id=XXX is the 'u32 type' in btf_type * * NOTE: "void" has type_id 0 * * String section: * ~~~~~~~~~~~~~~ * The BTF string section contains the names used by the type section. * Each string is referred by an "offset" from the beginning of the * string section. * * Each string is '\0' terminated. * * The first character in the string section must be '\0' * which is used to mean 'anonymous'. Some btf_type may not * have a name. */ /* BTF verification: * * To verify BTF data, two passes are needed. * * Pass #1 * ~~~~~~~ * The first pass is to collect all btf_type objects to * an array: "btf->types". * * Depending on the C type that a btf_type is describing, * a btf_type may be followed by extra data. We don't know * how many btf_type is there, and more importantly we don't * know where each btf_type is located in the type section. * * Without knowing the location of each type_id, most verifications * cannot be done. e.g. an earlier btf_type may refer to a later * btf_type (recall the "const void *" above), so we cannot * check this type-reference in the first pass. * * In the first pass, it still does some verifications (e.g. * checking the name is a valid offset to the string section). * * Pass #2 * ~~~~~~~ * The main focus is to resolve a btf_type that is referring * to another type. * * We have to ensure the referring type: * 1) does exist in the BTF (i.e. in btf->types[]) * 2) does not cause a loop: * struct A { * struct B b; * }; * * struct B { * struct A a; * }; * * btf_type_needs_resolve() decides if a btf_type needs * to be resolved. * * The needs_resolve type implements the "resolve()" ops which * essentially does a DFS and detects backedge. * * During resolve (or DFS), different C types have different * "RESOLVED" conditions. * * When resolving a BTF_KIND_STRUCT, we need to resolve all its * members because a member is always referring to another * type. A struct's member can be treated as "RESOLVED" if * it is referring to a BTF_KIND_PTR. Otherwise, the * following valid C struct would be rejected: * * struct A { * int m; * struct A *a; * }; * * When resolving a BTF_KIND_PTR, it needs to keep resolving if * it is referring to another BTF_KIND_PTR. Otherwise, we cannot * detect a pointer loop, e.g.: * BTF_KIND_CONST -> BTF_KIND_PTR -> BTF_KIND_CONST -> BTF_KIND_PTR + * ^ | * +-----------------------------------------+ * */ #define BITS_PER_U128 (sizeof(u64) * BITS_PER_BYTE * 2) #define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1) #define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK) #define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3) #define BITS_ROUNDUP_BYTES(bits) \ (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits)) #define BTF_INFO_MASK 0x8f00ffff #define BTF_INT_MASK 0x0fffffff #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE) #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET) /* 16MB for 64k structs and each has 16 members and * a few MB spaces for the string section. * The hard limit is S32_MAX. */ #define BTF_MAX_SIZE (16 * 1024 * 1024) #define for_each_member_from(i, from, struct_type, member) \ for (i = from, member = btf_type_member(struct_type) + from; \ i < btf_type_vlen(struct_type); \ i++, member++) #define for_each_vsi(i, struct_type, member) \ for (i = 0, member = btf_type_var_secinfo(struct_type); \ i < btf_type_vlen(struct_type); \ i++, member++) #define for_each_vsi_from(i, from, struct_type, member) \ for (i = from, member = btf_type_var_secinfo(struct_type) + from; \ i < btf_type_vlen(struct_type); \ i++, member++) DEFINE_IDR(btf_idr); DEFINE_SPINLOCK(btf_idr_lock); struct btf { void *data; struct btf_type **types; u32 *resolved_ids; u32 *resolved_sizes; const char *strings; void *nohdr_data; struct btf_header hdr; u32 nr_types; u32 types_size; u32 data_size; refcount_t refcnt; u32 id; struct rcu_head rcu; }; enum verifier_phase { CHECK_META, CHECK_TYPE, }; struct resolve_vertex { const struct btf_type *t; u32 type_id; u16 next_member; }; enum visit_state { NOT_VISITED, VISITED, RESOLVED, }; enum resolve_mode { RESOLVE_TBD, /* To Be Determined */ RESOLVE_PTR, /* Resolving for Pointer */ RESOLVE_STRUCT_OR_ARRAY, /* Resolving for struct/union * or array */ }; #define MAX_RESOLVE_DEPTH 32 struct btf_sec_info { u32 off; u32 len; }; struct btf_verifier_env { struct btf *btf; u8 *visit_states; struct resolve_vertex stack[MAX_RESOLVE_DEPTH]; struct bpf_verifier_log log; u32 log_type_id; u32 top_stack; enum verifier_phase phase; enum resolve_mode resolve_mode; }; static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_UNKN] = "UNKNOWN", [BTF_KIND_INT] = "INT", [BTF_KIND_PTR] = "PTR", [BTF_KIND_ARRAY] = "ARRAY", [BTF_KIND_STRUCT] = "STRUCT", [BTF_KIND_UNION] = "UNION", [BTF_KIND_ENUM] = "ENUM", [BTF_KIND_FWD] = "FWD", [BTF_KIND_TYPEDEF] = "TYPEDEF", [BTF_KIND_VOLATILE] = "VOLATILE", [BTF_KIND_CONST] = "CONST", [BTF_KIND_RESTRICT] = "RESTRICT", [BTF_KIND_FUNC] = "FUNC", [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", [BTF_KIND_VAR] = "VAR", [BTF_KIND_DATASEC] = "DATASEC", }; static const char *btf_type_str(const struct btf_type *t) { return btf_kind_str[BTF_INFO_KIND(t->info)]; } struct btf_kind_operations { s32 (*check_meta)(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left); int (*resolve)(struct btf_verifier_env *env, const struct resolve_vertex *v); int (*check_member)(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type); int (*check_kflag_member)(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type); void (*log_details)(struct btf_verifier_env *env, const struct btf_type *t); void (*seq_show)(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offsets, struct seq_file *m); }; static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS]; static struct btf_type btf_void; static int btf_resolve(struct btf_verifier_env *env, const struct btf_type *t, u32 type_id); static bool btf_type_is_modifier(const struct btf_type *t) { /* Some of them is not strictly a C modifier * but they are grouped into the same bucket * for BTF concern: * A type (t) that refers to another * type through t->type AND its size cannot * be determined without following the t->type. * * ptr does not fall into this bucket * because its size is always sizeof(void *). */ switch (BTF_INFO_KIND(t->info)) { case BTF_KIND_TYPEDEF: case BTF_KIND_VOLATILE: case BTF_KIND_CONST: case BTF_KIND_RESTRICT: return true; } return false; } bool btf_type_is_void(const struct btf_type *t) { return t == &btf_void; } static bool btf_type_is_fwd(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; } static bool btf_type_nosize(const struct btf_type *t) { return btf_type_is_void(t) || btf_type_is_fwd(t) || btf_type_is_func(t) || btf_type_is_func_proto(t); } static bool btf_type_nosize_or_null(const struct btf_type *t) { return !t || btf_type_nosize(t); } /* union is only a special case of struct: * all its offsetof(member) == 0 */ static bool btf_type_is_struct(const struct btf_type *t) { u8 kind = BTF_INFO_KIND(t->info); return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION; } static bool __btf_type_is_struct(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT; } static bool btf_type_is_array(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY; } static bool btf_type_is_var(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_VAR; } static bool btf_type_is_datasec(const struct btf_type *t) { return BTF_INFO_KIND(t->info) == BTF_KIND_DATASEC; } s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind) { const struct btf_type *t; const char *tname; u32 i; for (i = 1; i <= btf->nr_types; i++) { t = btf->types[i]; if (BTF_INFO_KIND(t->info) != kind) continue; tname = btf_name_by_offset(btf, t->name_off); if (!strcmp(tname, name)) return i; } return -ENOENT; } const struct btf_type *btf_type_skip_modifiers(const struct btf *btf, u32 id, u32 *res_id) { const struct btf_type *t = btf_type_by_id(btf, id); while (btf_type_is_modifier(t)) { id = t->type; t = btf_type_by_id(btf, t->type); } if (res_id) *res_id = id; return t; } const struct btf_type *btf_type_resolve_ptr(const struct btf *btf, u32 id, u32 *res_id) { const struct btf_type *t; t = btf_type_skip_modifiers(btf, id, NULL); if (!btf_type_is_ptr(t)) return NULL; return btf_type_skip_modifiers(btf, t->type, res_id); } const struct btf_type *btf_type_resolve_func_ptr(const struct btf *btf, u32 id, u32 *res_id) { const struct btf_type *ptype; ptype = btf_type_resolve_ptr(btf, id, res_id); if (ptype && btf_type_is_func_proto(ptype)) return ptype; return NULL; } /* Types that act only as a source, not sink or intermediate * type when resolving. */ static bool btf_type_is_resolve_source_only(const struct btf_type *t) { return btf_type_is_var(t) || btf_type_is_datasec(t); } /* What types need to be resolved? * * btf_type_is_modifier() is an obvious one. * * btf_type_is_struct() because its member refers to * another type (through member->type). * * btf_type_is_var() because the variable refers to * another type. btf_type_is_datasec() holds multiple * btf_type_is_var() types that need resolving. * * btf_type_is_array() because its element (array->type) * refers to another type. Array can be thought of a * special case of struct while array just has the same * member-type repeated by array->nelems of times. */ static bool btf_type_needs_resolve(const struct btf_type *t) { return btf_type_is_modifier(t) || btf_type_is_ptr(t) || btf_type_is_struct(t) || btf_type_is_array(t) || btf_type_is_var(t) || btf_type_is_datasec(t); } /* t->size can be used */ static bool btf_type_has_size(const struct btf_type *t) { switch (BTF_INFO_KIND(t->info)) { case BTF_KIND_INT: case BTF_KIND_STRUCT: case BTF_KIND_UNION: case BTF_KIND_ENUM: case BTF_KIND_DATASEC: return true; } return false; } static const char *btf_int_encoding_str(u8 encoding) { if (encoding == 0) return "(none)"; else if (encoding == BTF_INT_SIGNED) return "SIGNED"; else if (encoding == BTF_INT_CHAR) return "CHAR"; else if (encoding == BTF_INT_BOOL) return "BOOL"; else return "UNKN"; } static u32 btf_type_int(const struct btf_type *t) { return *(u32 *)(t + 1); } static const struct btf_array *btf_type_array(const struct btf_type *t) { return (const struct btf_array *)(t + 1); } static const struct btf_enum *btf_type_enum(const struct btf_type *t) { return (const struct btf_enum *)(t + 1); } static const struct btf_var *btf_type_var(const struct btf_type *t) { return (const struct btf_var *)(t + 1); } static const struct btf_var_secinfo *btf_type_var_secinfo(const struct btf_type *t) { return (const struct btf_var_secinfo *)(t + 1); } static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t) { return kind_ops[BTF_INFO_KIND(t->info)]; } static bool btf_name_offset_valid(const struct btf *btf, u32 offset) { return BTF_STR_OFFSET_VALID(offset) && offset < btf->hdr.str_len; } static bool __btf_name_char_ok(char c, bool first, bool dot_ok) { if ((first ? !isalpha(c) : !isalnum(c)) && c != '_' && ((c == '.' && !dot_ok) || c != '.')) return false; return true; } static bool __btf_name_valid(const struct btf *btf, u32 offset, bool dot_ok) { /* offset must be valid */ const char *src = &btf->strings[offset]; const char *src_limit; if (!__btf_name_char_ok(*src, true, dot_ok)) return false; /* set a limit on identifier length */ src_limit = src + KSYM_NAME_LEN; src++; while (*src && src < src_limit) { if (!__btf_name_char_ok(*src, false, dot_ok)) return false; src++; } return !*src; } /* Only C-style identifier is permitted. This can be relaxed if * necessary. */ static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) { return __btf_name_valid(btf, offset, false); } static bool btf_name_valid_section(const struct btf *btf, u32 offset) { return __btf_name_valid(btf, offset, true); } static const char *__btf_name_by_offset(const struct btf *btf, u32 offset) { if (!offset) return "(anon)"; else if (offset < btf->hdr.str_len) return &btf->strings[offset]; else return "(invalid-name-offset)"; } const char *btf_name_by_offset(const struct btf *btf, u32 offset) { if (offset < btf->hdr.str_len) return &btf->strings[offset]; return NULL; } const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id) { if (type_id > btf->nr_types) return NULL; return btf->types[type_id]; } /* * Regular int is not a bit field and it must be either * u8/u16/u32/u64 or __int128. */ static bool btf_type_int_is_regular(const struct btf_type *t) { u8 nr_bits, nr_bytes; u32 int_data; int_data = btf_type_int(t); nr_bits = BTF_INT_BITS(int_data); nr_bytes = BITS_ROUNDUP_BYTES(nr_bits); if (BITS_PER_BYTE_MASKED(nr_bits) || BTF_INT_OFFSET(int_data) || (nr_bytes != sizeof(u8) && nr_bytes != sizeof(u16) && nr_bytes != sizeof(u32) && nr_bytes != sizeof(u64) && nr_bytes != (2 * sizeof(u64)))) { return false; } return true; } /* * Check that given struct member is a regular int with expected * offset and size. */ bool btf_member_is_reg_int(const struct btf *btf, const struct btf_type *s, const struct btf_member *m, u32 expected_offset, u32 expected_size) { const struct btf_type *t; u32 id, int_data; u8 nr_bits; id = m->type; t = btf_type_id_size(btf, &id, NULL); if (!t || !btf_type_is_int(t)) return false; int_data = btf_type_int(t); nr_bits = BTF_INT_BITS(int_data); if (btf_type_kflag(s)) { u32 bitfield_size = BTF_MEMBER_BITFIELD_SIZE(m->offset); u32 bit_offset = BTF_MEMBER_BIT_OFFSET(m->offset); /* if kflag set, int should be a regular int and * bit offset should be at byte boundary. */ return !bitfield_size && BITS_ROUNDUP_BYTES(bit_offset) == expected_offset && BITS_ROUNDUP_BYTES(nr_bits) == expected_size; } if (BTF_INT_OFFSET(int_data) || BITS_PER_BYTE_MASKED(m->offset) || BITS_ROUNDUP_BYTES(m->offset) != expected_offset || BITS_PER_BYTE_MASKED(nr_bits) || BITS_ROUNDUP_BYTES(nr_bits) != expected_size) return false; return true; } __printf(2, 3) static void __btf_verifier_log(struct bpf_verifier_log *log, const char *fmt, ...) { va_list args; va_start(args, fmt); bpf_verifier_vlog(log, fmt, args); va_end(args); } __printf(2, 3) static void btf_verifier_log(struct btf_verifier_env *env, const char *fmt, ...) { struct bpf_verifier_log *log = &env->log; va_list args; if (!bpf_verifier_log_needed(log)) return; va_start(args, fmt); bpf_verifier_vlog(log, fmt, args); va_end(args); } __printf(4, 5) static void __btf_verifier_log_type(struct btf_verifier_env *env, const struct btf_type *t, bool log_details, const char *fmt, ...) { struct bpf_verifier_log *log = &env->log; u8 kind = BTF_INFO_KIND(t->info); struct btf *btf = env->btf; va_list args; if (!bpf_verifier_log_needed(log)) return; /* btf verifier prints all types it is processing via * btf_verifier_log_type(..., fmt = NULL). * Skip those prints for in-kernel BTF verification. */ if (log->level == BPF_LOG_KERNEL && !fmt) return; __btf_verifier_log(log, "[%u] %s %s%s", env->log_type_id, btf_kind_str[kind], __btf_name_by_offset(btf, t->name_off), log_details ? " " : ""); if (log_details) btf_type_ops(t)->log_details(env, t); if (fmt && *fmt) { __btf_verifier_log(log, " "); va_start(args, fmt); bpf_verifier_vlog(log, fmt, args); va_end(args); } __btf_verifier_log(log, "\n"); } #define btf_verifier_log_type(env, t, ...) \ __btf_verifier_log_type((env), (t), true, __VA_ARGS__) #define btf_verifier_log_basic(env, t, ...) \ __btf_verifier_log_type((env), (t), false, __VA_ARGS__) __printf(4, 5) static void btf_verifier_log_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const char *fmt, ...) { struct bpf_verifier_log *log = &env->log; struct btf *btf = env->btf; va_list args; if (!bpf_verifier_log_needed(log)) return; if (log->level == BPF_LOG_KERNEL && !fmt) return; /* The CHECK_META phase already did a btf dump. * * If member is logged again, it must hit an error in * parsing this member. It is useful to print out which * struct this member belongs to. */ if (env->phase != CHECK_META) btf_verifier_log_type(env, struct_type, NULL); if (btf_type_kflag(struct_type)) __btf_verifier_log(log, "\t%s type_id=%u bitfield_size=%u bits_offset=%u", __btf_name_by_offset(btf, member->name_off), member->type, BTF_MEMBER_BITFIELD_SIZE(member->offset), BTF_MEMBER_BIT_OFFSET(member->offset)); else __btf_verifier_log(log, "\t%s type_id=%u bits_offset=%u", __btf_name_by_offset(btf, member->name_off), member->type, member->offset); if (fmt && *fmt) { __btf_verifier_log(log, " "); va_start(args, fmt); bpf_verifier_vlog(log, fmt, args); va_end(args); } __btf_verifier_log(log, "\n"); } __printf(4, 5) static void btf_verifier_log_vsi(struct btf_verifier_env *env, const struct btf_type *datasec_type, const struct btf_var_secinfo *vsi, const char *fmt, ...) { struct bpf_verifier_log *log = &env->log; va_list args; if (!bpf_verifier_log_needed(log)) return; if (log->level == BPF_LOG_KERNEL && !fmt) return; if (env->phase != CHECK_META) btf_verifier_log_type(env, datasec_type, NULL); __btf_verifier_log(log, "\t type_id=%u offset=%u size=%u", vsi->type, vsi->offset, vsi->size); if (fmt && *fmt) { __btf_verifier_log(log, " "); va_start(args, fmt); bpf_verifier_vlog(log, fmt, args); va_end(args); } __btf_verifier_log(log, "\n"); } static void btf_verifier_log_hdr(struct btf_verifier_env *env, u32 btf_data_size) { struct bpf_verifier_log *log = &env->log; const struct btf *btf = env->btf; const struct btf_header *hdr; if (!bpf_verifier_log_needed(log)) return; if (log->level == BPF_LOG_KERNEL) return; hdr = &btf->hdr; __btf_verifier_log(log, "magic: 0x%x\n", hdr->magic); __btf_verifier_log(log, "version: %u\n", hdr->version); __btf_verifier_log(log, "flags: 0x%x\n", hdr->flags); __btf_verifier_log(log, "hdr_len: %u\n", hdr->hdr_len); __btf_verifier_log(log, "type_off: %u\n", hdr->type_off); __btf_verifier_log(log, "type_len: %u\n", hdr->type_len); __btf_verifier_log(log, "str_off: %u\n", hdr->str_off); __btf_verifier_log(log, "str_len: %u\n", hdr->str_len); __btf_verifier_log(log, "btf_total_size: %u\n", btf_data_size); } static int btf_add_type(struct btf_verifier_env *env, struct btf_type *t) { struct btf *btf = env->btf; /* < 2 because +1 for btf_void which is always in btf->types[0]. * btf_void is not accounted in btf->nr_types because btf_void * does not come from the BTF file. */ if (btf->types_size - btf->nr_types < 2) { /* Expand 'types' array */ struct btf_type **new_types; u32 expand_by, new_size; if (btf->types_size == BTF_MAX_TYPE) { btf_verifier_log(env, "Exceeded max num of types"); return -E2BIG; } expand_by = max_t(u32, btf->types_size >> 2, 16); new_size = min_t(u32, BTF_MAX_TYPE, btf->types_size + expand_by); new_types = kvcalloc(new_size, sizeof(*new_types), GFP_KERNEL | __GFP_NOWARN); if (!new_types) return -ENOMEM; if (btf->nr_types == 0) new_types[0] = &btf_void; else memcpy(new_types, btf->types, sizeof(*btf->types) * (btf->nr_types + 1)); kvfree(btf->types); btf->types = new_types; btf->types_size = new_size; } btf->types[++(btf->nr_types)] = t; return 0; } static int btf_alloc_id(struct btf *btf) { int id; idr_preload(GFP_KERNEL); spin_lock_bh(&btf_idr_lock); id = idr_alloc_cyclic(&btf_idr, btf, 1, INT_MAX, GFP_ATOMIC); if (id > 0) btf->id = id; spin_unlock_bh(&btf_idr_lock); idr_preload_end(); if (WARN_ON_ONCE(!id)) return -ENOSPC; return id > 0 ? 0 : id; } static void btf_free_id(struct btf *btf) { unsigned long flags; /* * In map-in-map, calling map_delete_elem() on outer * map will call bpf_map_put on the inner map. * It will then eventually call btf_free_id() * on the inner map. Some of the map_delete_elem() * implementation may have irq disabled, so * we need to use the _irqsave() version instead * of the _bh() version. */ spin_lock_irqsave(&btf_idr_lock, flags); idr_remove(&btf_idr, btf->id); spin_unlock_irqrestore(&btf_idr_lock, flags); } static void btf_free(struct btf *btf) { kvfree(btf->types); kvfree(btf->resolved_sizes); kvfree(btf->resolved_ids); kvfree(btf->data); kfree(btf); } static void btf_free_rcu(struct rcu_head *rcu) { struct btf *btf = container_of(rcu, struct btf, rcu); btf_free(btf); } void btf_put(struct btf *btf) { if (btf && refcount_dec_and_test(&btf->refcnt)) { btf_free_id(btf); call_rcu(&btf->rcu, btf_free_rcu); } } static int env_resolve_init(struct btf_verifier_env *env) { struct btf *btf = env->btf; u32 nr_types = btf->nr_types; u32 *resolved_sizes = NULL; u32 *resolved_ids = NULL; u8 *visit_states = NULL; /* +1 for btf_void */ resolved_sizes = kvcalloc(nr_types + 1, sizeof(*resolved_sizes), GFP_KERNEL | __GFP_NOWARN); if (!resolved_sizes) goto nomem; resolved_ids = kvcalloc(nr_types + 1, sizeof(*resolved_ids), GFP_KERNEL | __GFP_NOWARN); if (!resolved_ids) goto nomem; visit_states = kvcalloc(nr_types + 1, sizeof(*visit_states), GFP_KERNEL | __GFP_NOWARN); if (!visit_states) goto nomem; btf->resolved_sizes = resolved_sizes; btf->resolved_ids = resolved_ids; env->visit_states = visit_states; return 0; nomem: kvfree(resolved_sizes); kvfree(resolved_ids); kvfree(visit_states); return -ENOMEM; } static void btf_verifier_env_free(struct btf_verifier_env *env) { kvfree(env->visit_states); kfree(env); } static bool env_type_is_resolve_sink(const struct btf_verifier_env *env, const struct btf_type *next_type) { switch (env->resolve_mode) { case RESOLVE_TBD: /* int, enum or void is a sink */ return !btf_type_needs_resolve(next_type); case RESOLVE_PTR: /* int, enum, void, struct, array, func or func_proto is a sink * for ptr */ return !btf_type_is_modifier(next_type) && !btf_type_is_ptr(next_type); case RESOLVE_STRUCT_OR_ARRAY: /* int, enum, void, ptr, func or func_proto is a sink * for struct and array */ return !btf_type_is_modifier(next_type) && !btf_type_is_array(next_type) && !btf_type_is_struct(next_type); default: BUG(); } } static bool env_type_is_resolved(const struct btf_verifier_env *env, u32 type_id) { return env->visit_states[type_id] == RESOLVED; } static int env_stack_push(struct btf_verifier_env *env, const struct btf_type *t, u32 type_id) { struct resolve_vertex *v; if (env->top_stack == MAX_RESOLVE_DEPTH) return -E2BIG; if (env->visit_states[type_id] != NOT_VISITED) return -EEXIST; env->visit_states[type_id] = VISITED; v = &env->stack[env->top_stack++]; v->t = t; v->type_id = type_id; v->next_member = 0; if (env->resolve_mode == RESOLVE_TBD) { if (btf_type_is_ptr(t)) env->resolve_mode = RESOLVE_PTR; else if (btf_type_is_struct(t) || btf_type_is_array(t)) env->resolve_mode = RESOLVE_STRUCT_OR_ARRAY; } return 0; } static void env_stack_set_next_member(struct btf_verifier_env *env, u16 next_member) { env->stack[env->top_stack - 1].next_member = next_member; } static void env_stack_pop_resolved(struct btf_verifier_env *env, u32 resolved_type_id, u32 resolved_size) { u32 type_id = env->stack[--(env->top_stack)].type_id; struct btf *btf = env->btf; btf->resolved_sizes[type_id] = resolved_size; btf->resolved_ids[type_id] = resolved_type_id; env->visit_states[type_id] = RESOLVED; } static const struct resolve_vertex *env_stack_peak(struct btf_verifier_env *env) { return env->top_stack ? &env->stack[env->top_stack - 1] : NULL; } /* Resolve the size of a passed-in "type" * * type: is an array (e.g. u32 array[x][y]) * return type: type "u32[x][y]", i.e. BTF_KIND_ARRAY, * *type_size: (x * y * sizeof(u32)). Hence, *type_size always * corresponds to the return type. * *elem_type: u32 * *total_nelems: (x * y). Hence, individual elem size is * (*type_size / *total_nelems) * * type: is not an array (e.g. const struct X) * return type: type "struct X" * *type_size: sizeof(struct X) * *elem_type: same as return type ("struct X") * *total_nelems: 1 */ const struct btf_type * btf_resolve_size(const struct btf *btf, const struct btf_type *type, u32 *type_size, const struct btf_type **elem_type, u32 *total_nelems) { const struct btf_type *array_type = NULL; const struct btf_array *array; u32 i, size, nelems = 1; for (i = 0; i < MAX_RESOLVE_DEPTH; i++) { switch (BTF_INFO_KIND(type->info)) { /* type->size can be used */ case BTF_KIND_INT: case BTF_KIND_STRUCT: case BTF_KIND_UNION: case BTF_KIND_ENUM: size = type->size; goto resolved; case BTF_KIND_PTR: size = sizeof(void *); goto resolved; /* Modifiers */ case BTF_KIND_TYPEDEF: case BTF_KIND_VOLATILE: case BTF_KIND_CONST: case BTF_KIND_RESTRICT: type = btf_type_by_id(btf, type->type); break; case BTF_KIND_ARRAY: if (!array_type) array_type = type; array = btf_type_array(type); if (nelems && array->nelems > U32_MAX / nelems) return ERR_PTR(-EINVAL); nelems *= array->nelems; type = btf_type_by_id(btf, array->type); break; /* type without size */ default: return ERR_PTR(-EINVAL); } } return ERR_PTR(-EINVAL); resolved: if (nelems && size > U32_MAX / nelems) return ERR_PTR(-EINVAL); *type_size = nelems * size; if (total_nelems) *total_nelems = nelems; if (elem_type) *elem_type = type; return array_type ? : type; } /* The input param "type_id" must point to a needs_resolve type */ static const struct btf_type *btf_type_id_resolve(const struct btf *btf, u32 *type_id) { *type_id = btf->resolved_ids[*type_id]; return btf_type_by_id(btf, *type_id); } const struct btf_type *btf_type_id_size(const struct btf *btf, u32 *type_id, u32 *ret_size) { const struct btf_type *size_type; u32 size_type_id = *type_id; u32 size = 0; size_type = btf_type_by_id(btf, size_type_id); if (btf_type_nosize_or_null(size_type)) return NULL; if (btf_type_has_size(size_type)) { size = size_type->size; } else if (btf_type_is_array(size_type)) { size = btf->resolved_sizes[size_type_id]; } else if (btf_type_is_ptr(size_type)) { size = sizeof(void *); } else { if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) && !btf_type_is_var(size_type))) return NULL; size_type_id = btf->resolved_ids[size_type_id]; size_type = btf_type_by_id(btf, size_type_id); if (btf_type_nosize_or_null(size_type)) return NULL; else if (btf_type_has_size(size_type)) size = size_type->size; else if (btf_type_is_array(size_type)) size = btf->resolved_sizes[size_type_id]; else if (btf_type_is_ptr(size_type)) size = sizeof(void *); else return NULL; } *type_id = size_type_id; if (ret_size) *ret_size = size; return size_type; } static int btf_df_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { btf_verifier_log_basic(env, struct_type, "Unsupported check_member"); return -EINVAL; } static int btf_df_check_kflag_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { btf_verifier_log_basic(env, struct_type, "Unsupported check_kflag_member"); return -EINVAL; } /* Used for ptr, array and struct/union type members. * int, enum and modifier types have their specific callback functions. */ static int btf_generic_check_kflag_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { if (BTF_MEMBER_BITFIELD_SIZE(member->offset)) { btf_verifier_log_member(env, struct_type, member, "Invalid member bitfield_size"); return -EINVAL; } /* bitfield size is 0, so member->offset represents bit offset only. * It is safe to call non kflag check_member variants. */ return btf_type_ops(member_type)->check_member(env, struct_type, member, member_type); } static int btf_df_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { btf_verifier_log_basic(env, v->t, "Unsupported resolve"); return -EINVAL; } static void btf_df_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offsets, struct seq_file *m) { seq_printf(m, "", BTF_INFO_KIND(t->info)); } static int btf_int_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 int_data = btf_type_int(member_type); u32 struct_bits_off = member->offset; u32 struct_size = struct_type->size; u32 nr_copy_bits; u32 bytes_offset; if (U32_MAX - struct_bits_off < BTF_INT_OFFSET(int_data)) { btf_verifier_log_member(env, struct_type, member, "bits_offset exceeds U32_MAX"); return -EINVAL; } struct_bits_off += BTF_INT_OFFSET(int_data); bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); nr_copy_bits = BTF_INT_BITS(int_data) + BITS_PER_BYTE_MASKED(struct_bits_off); if (nr_copy_bits > BITS_PER_U128) { btf_verifier_log_member(env, struct_type, member, "nr_copy_bits exceeds 128"); return -EINVAL; } if (struct_size < bytes_offset || struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static int btf_int_check_kflag_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 struct_bits_off, nr_bits, nr_int_data_bits, bytes_offset; u32 int_data = btf_type_int(member_type); u32 struct_size = struct_type->size; u32 nr_copy_bits; /* a regular int type is required for the kflag int member */ if (!btf_type_int_is_regular(member_type)) { btf_verifier_log_member(env, struct_type, member, "Invalid member base type"); return -EINVAL; } /* check sanity of bitfield size */ nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset); struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset); nr_int_data_bits = BTF_INT_BITS(int_data); if (!nr_bits) { /* Not a bitfield member, member offset must be at byte * boundary. */ if (BITS_PER_BYTE_MASKED(struct_bits_off)) { btf_verifier_log_member(env, struct_type, member, "Invalid member offset"); return -EINVAL; } nr_bits = nr_int_data_bits; } else if (nr_bits > nr_int_data_bits) { btf_verifier_log_member(env, struct_type, member, "Invalid member bitfield_size"); return -EINVAL; } bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); nr_copy_bits = nr_bits + BITS_PER_BYTE_MASKED(struct_bits_off); if (nr_copy_bits > BITS_PER_U128) { btf_verifier_log_member(env, struct_type, member, "nr_copy_bits exceeds 128"); return -EINVAL; } if (struct_size < bytes_offset || struct_size - bytes_offset < BITS_ROUNDUP_BYTES(nr_copy_bits)) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static s32 btf_int_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { u32 int_data, nr_bits, meta_needed = sizeof(int_data); u16 encoding; if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } if (btf_type_vlen(t)) { btf_verifier_log_type(env, t, "vlen != 0"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } int_data = btf_type_int(t); if (int_data & ~BTF_INT_MASK) { btf_verifier_log_basic(env, t, "Invalid int_data:%x", int_data); return -EINVAL; } nr_bits = BTF_INT_BITS(int_data) + BTF_INT_OFFSET(int_data); if (nr_bits > BITS_PER_U128) { btf_verifier_log_type(env, t, "nr_bits exceeds %zu", BITS_PER_U128); return -EINVAL; } if (BITS_ROUNDUP_BYTES(nr_bits) > t->size) { btf_verifier_log_type(env, t, "nr_bits exceeds type_size"); return -EINVAL; } /* * Only one of the encoding bits is allowed and it * should be sufficient for the pretty print purpose (i.e. decoding). * Multiple bits can be allowed later if it is found * to be insufficient. */ encoding = BTF_INT_ENCODING(int_data); if (encoding && encoding != BTF_INT_SIGNED && encoding != BTF_INT_CHAR && encoding != BTF_INT_BOOL) { btf_verifier_log_type(env, t, "Unsupported encoding"); return -ENOTSUPP; } btf_verifier_log_type(env, t, NULL); return meta_needed; } static void btf_int_log(struct btf_verifier_env *env, const struct btf_type *t) { int int_data = btf_type_int(t); btf_verifier_log(env, "size=%u bits_offset=%u nr_bits=%u encoding=%s", t->size, BTF_INT_OFFSET(int_data), BTF_INT_BITS(int_data), btf_int_encoding_str(BTF_INT_ENCODING(int_data))); } static void btf_int128_print(struct seq_file *m, void *data) { /* data points to a __int128 number. * Suppose * int128_num = *(__int128 *)data; * The below formulas shows what upper_num and lower_num represents: * upper_num = int128_num >> 64; * lower_num = int128_num & 0xffffffffFFFFFFFFULL; */ u64 upper_num, lower_num; #ifdef __BIG_ENDIAN_BITFIELD upper_num = *(u64 *)data; lower_num = *(u64 *)(data + 8); #else upper_num = *(u64 *)(data + 8); lower_num = *(u64 *)data; #endif if (upper_num == 0) seq_printf(m, "0x%llx", lower_num); else seq_printf(m, "0x%llx%016llx", upper_num, lower_num); } static void btf_int128_shift(u64 *print_num, u16 left_shift_bits, u16 right_shift_bits) { u64 upper_num, lower_num; #ifdef __BIG_ENDIAN_BITFIELD upper_num = print_num[0]; lower_num = print_num[1]; #else upper_num = print_num[1]; lower_num = print_num[0]; #endif /* shake out un-needed bits by shift/or operations */ if (left_shift_bits >= 64) { upper_num = lower_num << (left_shift_bits - 64); lower_num = 0; } else { upper_num = (upper_num << left_shift_bits) | (lower_num >> (64 - left_shift_bits)); lower_num = lower_num << left_shift_bits; } if (right_shift_bits >= 64) { lower_num = upper_num >> (right_shift_bits - 64); upper_num = 0; } else { lower_num = (lower_num >> right_shift_bits) | (upper_num << (64 - right_shift_bits)); upper_num = upper_num >> right_shift_bits; } #ifdef __BIG_ENDIAN_BITFIELD print_num[0] = upper_num; print_num[1] = lower_num; #else print_num[0] = lower_num; print_num[1] = upper_num; #endif } static void btf_bitfield_seq_show(void *data, u8 bits_offset, u8 nr_bits, struct seq_file *m) { u16 left_shift_bits, right_shift_bits; u8 nr_copy_bytes; u8 nr_copy_bits; u64 print_num[2] = {}; nr_copy_bits = nr_bits + bits_offset; nr_copy_bytes = BITS_ROUNDUP_BYTES(nr_copy_bits); memcpy(print_num, data, nr_copy_bytes); #ifdef __BIG_ENDIAN_BITFIELD left_shift_bits = bits_offset; #else left_shift_bits = BITS_PER_U128 - nr_copy_bits; #endif right_shift_bits = BITS_PER_U128 - nr_bits; btf_int128_shift(print_num, left_shift_bits, right_shift_bits); btf_int128_print(m, print_num); } static void btf_int_bits_seq_show(const struct btf *btf, const struct btf_type *t, void *data, u8 bits_offset, struct seq_file *m) { u32 int_data = btf_type_int(t); u8 nr_bits = BTF_INT_BITS(int_data); u8 total_bits_offset; /* * bits_offset is at most 7. * BTF_INT_OFFSET() cannot exceed 128 bits. */ total_bits_offset = bits_offset + BTF_INT_OFFSET(int_data); data += BITS_ROUNDDOWN_BYTES(total_bits_offset); bits_offset = BITS_PER_BYTE_MASKED(total_bits_offset); btf_bitfield_seq_show(data, bits_offset, nr_bits, m); } static void btf_int_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { u32 int_data = btf_type_int(t); u8 encoding = BTF_INT_ENCODING(int_data); bool sign = encoding & BTF_INT_SIGNED; u8 nr_bits = BTF_INT_BITS(int_data); if (bits_offset || BTF_INT_OFFSET(int_data) || BITS_PER_BYTE_MASKED(nr_bits)) { btf_int_bits_seq_show(btf, t, data, bits_offset, m); return; } switch (nr_bits) { case 128: btf_int128_print(m, data); break; case 64: if (sign) seq_printf(m, "%lld", *(s64 *)data); else seq_printf(m, "%llu", *(u64 *)data); break; case 32: if (sign) seq_printf(m, "%d", *(s32 *)data); else seq_printf(m, "%u", *(u32 *)data); break; case 16: if (sign) seq_printf(m, "%d", *(s16 *)data); else seq_printf(m, "%u", *(u16 *)data); break; case 8: if (sign) seq_printf(m, "%d", *(s8 *)data); else seq_printf(m, "%u", *(u8 *)data); break; default: btf_int_bits_seq_show(btf, t, data, bits_offset, m); } } static const struct btf_kind_operations int_ops = { .check_meta = btf_int_check_meta, .resolve = btf_df_resolve, .check_member = btf_int_check_member, .check_kflag_member = btf_int_check_kflag_member, .log_details = btf_int_log, .seq_show = btf_int_seq_show, }; static int btf_modifier_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { const struct btf_type *resolved_type; u32 resolved_type_id = member->type; struct btf_member resolved_member; struct btf *btf = env->btf; resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); if (!resolved_type) { btf_verifier_log_member(env, struct_type, member, "Invalid member"); return -EINVAL; } resolved_member = *member; resolved_member.type = resolved_type_id; return btf_type_ops(resolved_type)->check_member(env, struct_type, &resolved_member, resolved_type); } static int btf_modifier_check_kflag_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { const struct btf_type *resolved_type; u32 resolved_type_id = member->type; struct btf_member resolved_member; struct btf *btf = env->btf; resolved_type = btf_type_id_size(btf, &resolved_type_id, NULL); if (!resolved_type) { btf_verifier_log_member(env, struct_type, member, "Invalid member"); return -EINVAL; } resolved_member = *member; resolved_member.type = resolved_type_id; return btf_type_ops(resolved_type)->check_kflag_member(env, struct_type, &resolved_member, resolved_type); } static int btf_ptr_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 struct_size, struct_bits_off, bytes_offset; struct_size = struct_type->size; struct_bits_off = member->offset; bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); if (BITS_PER_BYTE_MASKED(struct_bits_off)) { btf_verifier_log_member(env, struct_type, member, "Member is not byte aligned"); return -EINVAL; } if (struct_size - bytes_offset < sizeof(void *)) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static int btf_ref_type_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { if (btf_type_vlen(t)) { btf_verifier_log_type(env, t, "vlen != 0"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } if (!BTF_TYPE_ID_VALID(t->type)) { btf_verifier_log_type(env, t, "Invalid type_id"); return -EINVAL; } /* typedef type must have a valid name, and other ref types, * volatile, const, restrict, should have a null name. */ if (BTF_INFO_KIND(t->info) == BTF_KIND_TYPEDEF) { if (!t->name_off || !btf_name_valid_identifier(env->btf, t->name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } } else { if (t->name_off) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } } btf_verifier_log_type(env, t, NULL); return 0; } static int btf_modifier_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { const struct btf_type *t = v->t; const struct btf_type *next_type; u32 next_type_id = t->type; struct btf *btf = env->btf; next_type = btf_type_by_id(btf, next_type_id); if (!next_type || btf_type_is_resolve_source_only(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } if (!env_type_is_resolve_sink(env, next_type) && !env_type_is_resolved(env, next_type_id)) return env_stack_push(env, next_type, next_type_id); /* Figure out the resolved next_type_id with size. * They will be stored in the current modifier's * resolved_ids and resolved_sizes such that it can * save us a few type-following when we use it later (e.g. in * pretty print). */ if (!btf_type_id_size(btf, &next_type_id, NULL)) { if (env_type_is_resolved(env, next_type_id)) next_type = btf_type_id_resolve(btf, &next_type_id); /* "typedef void new_void", "const void"...etc */ if (!btf_type_is_void(next_type) && !btf_type_is_fwd(next_type) && !btf_type_is_func_proto(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } } env_stack_pop_resolved(env, next_type_id, 0); return 0; } static int btf_var_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { const struct btf_type *next_type; const struct btf_type *t = v->t; u32 next_type_id = t->type; struct btf *btf = env->btf; next_type = btf_type_by_id(btf, next_type_id); if (!next_type || btf_type_is_resolve_source_only(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } if (!env_type_is_resolve_sink(env, next_type) && !env_type_is_resolved(env, next_type_id)) return env_stack_push(env, next_type, next_type_id); if (btf_type_is_modifier(next_type)) { const struct btf_type *resolved_type; u32 resolved_type_id; resolved_type_id = next_type_id; resolved_type = btf_type_id_resolve(btf, &resolved_type_id); if (btf_type_is_ptr(resolved_type) && !env_type_is_resolve_sink(env, resolved_type) && !env_type_is_resolved(env, resolved_type_id)) return env_stack_push(env, resolved_type, resolved_type_id); } /* We must resolve to something concrete at this point, no * forward types or similar that would resolve to size of * zero is allowed. */ if (!btf_type_id_size(btf, &next_type_id, NULL)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } env_stack_pop_resolved(env, next_type_id, 0); return 0; } static int btf_ptr_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { const struct btf_type *next_type; const struct btf_type *t = v->t; u32 next_type_id = t->type; struct btf *btf = env->btf; next_type = btf_type_by_id(btf, next_type_id); if (!next_type || btf_type_is_resolve_source_only(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } if (!env_type_is_resolve_sink(env, next_type) && !env_type_is_resolved(env, next_type_id)) return env_stack_push(env, next_type, next_type_id); /* If the modifier was RESOLVED during RESOLVE_STRUCT_OR_ARRAY, * the modifier may have stopped resolving when it was resolved * to a ptr (last-resolved-ptr). * * We now need to continue from the last-resolved-ptr to * ensure the last-resolved-ptr will not referring back to * the currenct ptr (t). */ if (btf_type_is_modifier(next_type)) { const struct btf_type *resolved_type; u32 resolved_type_id; resolved_type_id = next_type_id; resolved_type = btf_type_id_resolve(btf, &resolved_type_id); if (btf_type_is_ptr(resolved_type) && !env_type_is_resolve_sink(env, resolved_type) && !env_type_is_resolved(env, resolved_type_id)) return env_stack_push(env, resolved_type, resolved_type_id); } if (!btf_type_id_size(btf, &next_type_id, NULL)) { if (env_type_is_resolved(env, next_type_id)) next_type = btf_type_id_resolve(btf, &next_type_id); if (!btf_type_is_void(next_type) && !btf_type_is_fwd(next_type) && !btf_type_is_func_proto(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } } env_stack_pop_resolved(env, next_type_id, 0); return 0; } static void btf_modifier_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { if (btf->resolved_ids) t = btf_type_id_resolve(btf, &type_id); else t = btf_type_skip_modifiers(btf, type_id, NULL); btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m); } static void btf_var_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { t = btf_type_id_resolve(btf, &type_id); btf_type_ops(t)->seq_show(btf, t, type_id, data, bits_offset, m); } static void btf_ptr_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { /* It is a hashed value */ seq_printf(m, "%p", *(void **)data); } static void btf_ref_type_log(struct btf_verifier_env *env, const struct btf_type *t) { btf_verifier_log(env, "type_id=%u", t->type); } static struct btf_kind_operations modifier_ops = { .check_meta = btf_ref_type_check_meta, .resolve = btf_modifier_resolve, .check_member = btf_modifier_check_member, .check_kflag_member = btf_modifier_check_kflag_member, .log_details = btf_ref_type_log, .seq_show = btf_modifier_seq_show, }; static struct btf_kind_operations ptr_ops = { .check_meta = btf_ref_type_check_meta, .resolve = btf_ptr_resolve, .check_member = btf_ptr_check_member, .check_kflag_member = btf_generic_check_kflag_member, .log_details = btf_ref_type_log, .seq_show = btf_ptr_seq_show, }; static s32 btf_fwd_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { if (btf_type_vlen(t)) { btf_verifier_log_type(env, t, "vlen != 0"); return -EINVAL; } if (t->type) { btf_verifier_log_type(env, t, "type != 0"); return -EINVAL; } /* fwd type must have a valid name */ if (!t->name_off || !btf_name_valid_identifier(env->btf, t->name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); return 0; } static void btf_fwd_type_log(struct btf_verifier_env *env, const struct btf_type *t) { btf_verifier_log(env, "%s", btf_type_kflag(t) ? "union" : "struct"); } static struct btf_kind_operations fwd_ops = { .check_meta = btf_fwd_check_meta, .resolve = btf_df_resolve, .check_member = btf_df_check_member, .check_kflag_member = btf_df_check_kflag_member, .log_details = btf_fwd_type_log, .seq_show = btf_df_seq_show, }; static int btf_array_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 struct_bits_off = member->offset; u32 struct_size, bytes_offset; u32 array_type_id, array_size; struct btf *btf = env->btf; if (BITS_PER_BYTE_MASKED(struct_bits_off)) { btf_verifier_log_member(env, struct_type, member, "Member is not byte aligned"); return -EINVAL; } array_type_id = member->type; btf_type_id_size(btf, &array_type_id, &array_size); struct_size = struct_type->size; bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); if (struct_size - bytes_offset < array_size) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static s32 btf_array_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { const struct btf_array *array = btf_type_array(t); u32 meta_needed = sizeof(*array); if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } /* array type should not have a name */ if (t->name_off) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } if (btf_type_vlen(t)) { btf_verifier_log_type(env, t, "vlen != 0"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } if (t->size) { btf_verifier_log_type(env, t, "size != 0"); return -EINVAL; } /* Array elem type and index type cannot be in type void, * so !array->type and !array->index_type are not allowed. */ if (!array->type || !BTF_TYPE_ID_VALID(array->type)) { btf_verifier_log_type(env, t, "Invalid elem"); return -EINVAL; } if (!array->index_type || !BTF_TYPE_ID_VALID(array->index_type)) { btf_verifier_log_type(env, t, "Invalid index"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); return meta_needed; } static int btf_array_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { const struct btf_array *array = btf_type_array(v->t); const struct btf_type *elem_type, *index_type; u32 elem_type_id, index_type_id; struct btf *btf = env->btf; u32 elem_size; /* Check array->index_type */ index_type_id = array->index_type; index_type = btf_type_by_id(btf, index_type_id); if (btf_type_nosize_or_null(index_type) || btf_type_is_resolve_source_only(index_type)) { btf_verifier_log_type(env, v->t, "Invalid index"); return -EINVAL; } if (!env_type_is_resolve_sink(env, index_type) && !env_type_is_resolved(env, index_type_id)) return env_stack_push(env, index_type, index_type_id); index_type = btf_type_id_size(btf, &index_type_id, NULL); if (!index_type || !btf_type_is_int(index_type) || !btf_type_int_is_regular(index_type)) { btf_verifier_log_type(env, v->t, "Invalid index"); return -EINVAL; } /* Check array->type */ elem_type_id = array->type; elem_type = btf_type_by_id(btf, elem_type_id); if (btf_type_nosize_or_null(elem_type) || btf_type_is_resolve_source_only(elem_type)) { btf_verifier_log_type(env, v->t, "Invalid elem"); return -EINVAL; } if (!env_type_is_resolve_sink(env, elem_type) && !env_type_is_resolved(env, elem_type_id)) return env_stack_push(env, elem_type, elem_type_id); elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); if (!elem_type) { btf_verifier_log_type(env, v->t, "Invalid elem"); return -EINVAL; } if (btf_type_is_int(elem_type) && !btf_type_int_is_regular(elem_type)) { btf_verifier_log_type(env, v->t, "Invalid array of int"); return -EINVAL; } if (array->nelems && elem_size > U32_MAX / array->nelems) { btf_verifier_log_type(env, v->t, "Array size overflows U32_MAX"); return -EINVAL; } env_stack_pop_resolved(env, elem_type_id, elem_size * array->nelems); return 0; } static void btf_array_log(struct btf_verifier_env *env, const struct btf_type *t) { const struct btf_array *array = btf_type_array(t); btf_verifier_log(env, "type_id=%u index_type_id=%u nr_elems=%u", array->type, array->index_type, array->nelems); } static void btf_array_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { const struct btf_array *array = btf_type_array(t); const struct btf_kind_operations *elem_ops; const struct btf_type *elem_type; u32 i, elem_size, elem_type_id; elem_type_id = array->type; elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); elem_ops = btf_type_ops(elem_type); seq_puts(m, "["); for (i = 0; i < array->nelems; i++) { if (i) seq_puts(m, ","); elem_ops->seq_show(btf, elem_type, elem_type_id, data, bits_offset, m); data += elem_size; } seq_puts(m, "]"); } static struct btf_kind_operations array_ops = { .check_meta = btf_array_check_meta, .resolve = btf_array_resolve, .check_member = btf_array_check_member, .check_kflag_member = btf_generic_check_kflag_member, .log_details = btf_array_log, .seq_show = btf_array_seq_show, }; static int btf_struct_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 struct_bits_off = member->offset; u32 struct_size, bytes_offset; if (BITS_PER_BYTE_MASKED(struct_bits_off)) { btf_verifier_log_member(env, struct_type, member, "Member is not byte aligned"); return -EINVAL; } struct_size = struct_type->size; bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); if (struct_size - bytes_offset < member_type->size) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static s32 btf_struct_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { bool is_union = BTF_INFO_KIND(t->info) == BTF_KIND_UNION; const struct btf_member *member; u32 meta_needed, last_offset; struct btf *btf = env->btf; u32 struct_size = t->size; u32 offset; u16 i; meta_needed = btf_type_vlen(t) * sizeof(*member); if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } /* struct type either no name or a valid one */ if (t->name_off && !btf_name_valid_identifier(env->btf, t->name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); last_offset = 0; for_each_member(i, t, member) { if (!btf_name_offset_valid(btf, member->name_off)) { btf_verifier_log_member(env, t, member, "Invalid member name_offset:%u", member->name_off); return -EINVAL; } /* struct member either no name or a valid one */ if (member->name_off && !btf_name_valid_identifier(btf, member->name_off)) { btf_verifier_log_member(env, t, member, "Invalid name"); return -EINVAL; } /* A member cannot be in type void */ if (!member->type || !BTF_TYPE_ID_VALID(member->type)) { btf_verifier_log_member(env, t, member, "Invalid type_id"); return -EINVAL; } offset = btf_member_bit_offset(t, member); if (is_union && offset) { btf_verifier_log_member(env, t, member, "Invalid member bits_offset"); return -EINVAL; } /* * ">" instead of ">=" because the last member could be * "char a[0];" */ if (last_offset > offset) { btf_verifier_log_member(env, t, member, "Invalid member bits_offset"); return -EINVAL; } if (BITS_ROUNDUP_BYTES(offset) > struct_size) { btf_verifier_log_member(env, t, member, "Member bits_offset exceeds its struct size"); return -EINVAL; } btf_verifier_log_member(env, t, member, NULL); last_offset = offset; } return meta_needed; } static int btf_struct_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { const struct btf_member *member; int err; u16 i; /* Before continue resolving the next_member, * ensure the last member is indeed resolved to a * type with size info. */ if (v->next_member) { const struct btf_type *last_member_type; const struct btf_member *last_member; u16 last_member_type_id; last_member = btf_type_member(v->t) + v->next_member - 1; last_member_type_id = last_member->type; if (WARN_ON_ONCE(!env_type_is_resolved(env, last_member_type_id))) return -EINVAL; last_member_type = btf_type_by_id(env->btf, last_member_type_id); if (btf_type_kflag(v->t)) err = btf_type_ops(last_member_type)->check_kflag_member(env, v->t, last_member, last_member_type); else err = btf_type_ops(last_member_type)->check_member(env, v->t, last_member, last_member_type); if (err) return err; } for_each_member_from(i, v->next_member, v->t, member) { u32 member_type_id = member->type; const struct btf_type *member_type = btf_type_by_id(env->btf, member_type_id); if (btf_type_nosize_or_null(member_type) || btf_type_is_resolve_source_only(member_type)) { btf_verifier_log_member(env, v->t, member, "Invalid member"); return -EINVAL; } if (!env_type_is_resolve_sink(env, member_type) && !env_type_is_resolved(env, member_type_id)) { env_stack_set_next_member(env, i + 1); return env_stack_push(env, member_type, member_type_id); } if (btf_type_kflag(v->t)) err = btf_type_ops(member_type)->check_kflag_member(env, v->t, member, member_type); else err = btf_type_ops(member_type)->check_member(env, v->t, member, member_type); if (err) return err; } env_stack_pop_resolved(env, 0, 0); return 0; } static void btf_struct_log(struct btf_verifier_env *env, const struct btf_type *t) { btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); } /* find 'struct bpf_spin_lock' in map value. * return >= 0 offset if found * and < 0 in case of error */ int btf_find_spin_lock(const struct btf *btf, const struct btf_type *t) { const struct btf_member *member; u32 i, off = -ENOENT; if (!__btf_type_is_struct(t)) return -EINVAL; for_each_member(i, t, member) { const struct btf_type *member_type = btf_type_by_id(btf, member->type); if (!__btf_type_is_struct(member_type)) continue; if (member_type->size != sizeof(struct bpf_spin_lock)) continue; if (strcmp(__btf_name_by_offset(btf, member_type->name_off), "bpf_spin_lock")) continue; if (off != -ENOENT) /* only one 'struct bpf_spin_lock' is allowed */ return -E2BIG; off = btf_member_bit_offset(t, member); if (off % 8) /* valid C code cannot generate such BTF */ return -EINVAL; off /= 8; if (off % __alignof__(struct bpf_spin_lock)) /* valid struct bpf_spin_lock will be 4 byte aligned */ return -EINVAL; } return off; } static void btf_struct_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { const char *seq = BTF_INFO_KIND(t->info) == BTF_KIND_UNION ? "|" : ","; const struct btf_member *member; u32 i; seq_puts(m, "{"); for_each_member(i, t, member) { const struct btf_type *member_type = btf_type_by_id(btf, member->type); const struct btf_kind_operations *ops; u32 member_offset, bitfield_size; u32 bytes_offset; u8 bits8_offset; if (i) seq_puts(m, seq); member_offset = btf_member_bit_offset(t, member); bitfield_size = btf_member_bitfield_size(t, member); bytes_offset = BITS_ROUNDDOWN_BYTES(member_offset); bits8_offset = BITS_PER_BYTE_MASKED(member_offset); if (bitfield_size) { btf_bitfield_seq_show(data + bytes_offset, bits8_offset, bitfield_size, m); } else { ops = btf_type_ops(member_type); ops->seq_show(btf, member_type, member->type, data + bytes_offset, bits8_offset, m); } } seq_puts(m, "}"); } static struct btf_kind_operations struct_ops = { .check_meta = btf_struct_check_meta, .resolve = btf_struct_resolve, .check_member = btf_struct_check_member, .check_kflag_member = btf_generic_check_kflag_member, .log_details = btf_struct_log, .seq_show = btf_struct_seq_show, }; static int btf_enum_check_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 struct_bits_off = member->offset; u32 struct_size, bytes_offset; if (BITS_PER_BYTE_MASKED(struct_bits_off)) { btf_verifier_log_member(env, struct_type, member, "Member is not byte aligned"); return -EINVAL; } struct_size = struct_type->size; bytes_offset = BITS_ROUNDDOWN_BYTES(struct_bits_off); if (struct_size - bytes_offset < sizeof(int)) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static int btf_enum_check_kflag_member(struct btf_verifier_env *env, const struct btf_type *struct_type, const struct btf_member *member, const struct btf_type *member_type) { u32 struct_bits_off, nr_bits, bytes_end, struct_size; u32 int_bitsize = sizeof(int) * BITS_PER_BYTE; struct_bits_off = BTF_MEMBER_BIT_OFFSET(member->offset); nr_bits = BTF_MEMBER_BITFIELD_SIZE(member->offset); if (!nr_bits) { if (BITS_PER_BYTE_MASKED(struct_bits_off)) { btf_verifier_log_member(env, struct_type, member, "Member is not byte aligned"); return -EINVAL; } nr_bits = int_bitsize; } else if (nr_bits > int_bitsize) { btf_verifier_log_member(env, struct_type, member, "Invalid member bitfield_size"); return -EINVAL; } struct_size = struct_type->size; bytes_end = BITS_ROUNDUP_BYTES(struct_bits_off + nr_bits); if (struct_size < bytes_end) { btf_verifier_log_member(env, struct_type, member, "Member exceeds struct_size"); return -EINVAL; } return 0; } static s32 btf_enum_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { const struct btf_enum *enums = btf_type_enum(t); struct btf *btf = env->btf; u16 i, nr_enums; u32 meta_needed; nr_enums = btf_type_vlen(t); meta_needed = nr_enums * sizeof(*enums); if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } if (t->size > 8 || !is_power_of_2(t->size)) { btf_verifier_log_type(env, t, "Unexpected size"); return -EINVAL; } /* enum type either no name or a valid one */ if (t->name_off && !btf_name_valid_identifier(env->btf, t->name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); for (i = 0; i < nr_enums; i++) { if (!btf_name_offset_valid(btf, enums[i].name_off)) { btf_verifier_log(env, "\tInvalid name_offset:%u", enums[i].name_off); return -EINVAL; } /* enum member must have a valid name */ if (!enums[i].name_off || !btf_name_valid_identifier(btf, enums[i].name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } if (env->log.level == BPF_LOG_KERNEL) continue; btf_verifier_log(env, "\t%s val=%d\n", __btf_name_by_offset(btf, enums[i].name_off), enums[i].val); } return meta_needed; } static void btf_enum_log(struct btf_verifier_env *env, const struct btf_type *t) { btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); } static void btf_enum_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { const struct btf_enum *enums = btf_type_enum(t); u32 i, nr_enums = btf_type_vlen(t); int v = *(int *)data; for (i = 0; i < nr_enums; i++) { if (v == enums[i].val) { seq_printf(m, "%s", __btf_name_by_offset(btf, enums[i].name_off)); return; } } seq_printf(m, "%d", v); } static struct btf_kind_operations enum_ops = { .check_meta = btf_enum_check_meta, .resolve = btf_df_resolve, .check_member = btf_enum_check_member, .check_kflag_member = btf_enum_check_kflag_member, .log_details = btf_enum_log, .seq_show = btf_enum_seq_show, }; static s32 btf_func_proto_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { u32 meta_needed = btf_type_vlen(t) * sizeof(struct btf_param); if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } if (t->name_off) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); return meta_needed; } static void btf_func_proto_log(struct btf_verifier_env *env, const struct btf_type *t) { const struct btf_param *args = (const struct btf_param *)(t + 1); u16 nr_args = btf_type_vlen(t), i; btf_verifier_log(env, "return=%u args=(", t->type); if (!nr_args) { btf_verifier_log(env, "void"); goto done; } if (nr_args == 1 && !args[0].type) { /* Only one vararg */ btf_verifier_log(env, "vararg"); goto done; } btf_verifier_log(env, "%u %s", args[0].type, __btf_name_by_offset(env->btf, args[0].name_off)); for (i = 1; i < nr_args - 1; i++) btf_verifier_log(env, ", %u %s", args[i].type, __btf_name_by_offset(env->btf, args[i].name_off)); if (nr_args > 1) { const struct btf_param *last_arg = &args[nr_args - 1]; if (last_arg->type) btf_verifier_log(env, ", %u %s", last_arg->type, __btf_name_by_offset(env->btf, last_arg->name_off)); else btf_verifier_log(env, ", vararg"); } done: btf_verifier_log(env, ")"); } static struct btf_kind_operations func_proto_ops = { .check_meta = btf_func_proto_check_meta, .resolve = btf_df_resolve, /* * BTF_KIND_FUNC_PROTO cannot be directly referred by * a struct's member. * * It should be a funciton pointer instead. * (i.e. struct's member -> BTF_KIND_PTR -> BTF_KIND_FUNC_PROTO) * * Hence, there is no btf_func_check_member(). */ .check_member = btf_df_check_member, .check_kflag_member = btf_df_check_kflag_member, .log_details = btf_func_proto_log, .seq_show = btf_df_seq_show, }; static s32 btf_func_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { if (!t->name_off || !btf_name_valid_identifier(env->btf, t->name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } if (btf_type_vlen(t) > BTF_FUNC_GLOBAL) { btf_verifier_log_type(env, t, "Invalid func linkage"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); return 0; } static struct btf_kind_operations func_ops = { .check_meta = btf_func_check_meta, .resolve = btf_df_resolve, .check_member = btf_df_check_member, .check_kflag_member = btf_df_check_kflag_member, .log_details = btf_ref_type_log, .seq_show = btf_df_seq_show, }; static s32 btf_var_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { const struct btf_var *var; u32 meta_needed = sizeof(*var); if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } if (btf_type_vlen(t)) { btf_verifier_log_type(env, t, "vlen != 0"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } if (!t->name_off || !__btf_name_valid(env->btf, t->name_off, true)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } /* A var cannot be in type void */ if (!t->type || !BTF_TYPE_ID_VALID(t->type)) { btf_verifier_log_type(env, t, "Invalid type_id"); return -EINVAL; } var = btf_type_var(t); if (var->linkage != BTF_VAR_STATIC && var->linkage != BTF_VAR_GLOBAL_ALLOCATED) { btf_verifier_log_type(env, t, "Linkage not supported"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); return meta_needed; } static void btf_var_log(struct btf_verifier_env *env, const struct btf_type *t) { const struct btf_var *var = btf_type_var(t); btf_verifier_log(env, "type_id=%u linkage=%u", t->type, var->linkage); } static const struct btf_kind_operations var_ops = { .check_meta = btf_var_check_meta, .resolve = btf_var_resolve, .check_member = btf_df_check_member, .check_kflag_member = btf_df_check_kflag_member, .log_details = btf_var_log, .seq_show = btf_var_seq_show, }; static s32 btf_datasec_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { const struct btf_var_secinfo *vsi; u64 last_vsi_end_off = 0, sum = 0; u32 i, meta_needed; meta_needed = btf_type_vlen(t) * sizeof(*vsi); if (meta_left < meta_needed) { btf_verifier_log_basic(env, t, "meta_left:%u meta_needed:%u", meta_left, meta_needed); return -EINVAL; } if (!btf_type_vlen(t)) { btf_verifier_log_type(env, t, "vlen == 0"); return -EINVAL; } if (!t->size) { btf_verifier_log_type(env, t, "size == 0"); return -EINVAL; } if (btf_type_kflag(t)) { btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); return -EINVAL; } if (!t->name_off || !btf_name_valid_section(env->btf, t->name_off)) { btf_verifier_log_type(env, t, "Invalid name"); return -EINVAL; } btf_verifier_log_type(env, t, NULL); for_each_vsi(i, t, vsi) { /* A var cannot be in type void */ if (!vsi->type || !BTF_TYPE_ID_VALID(vsi->type)) { btf_verifier_log_vsi(env, t, vsi, "Invalid type_id"); return -EINVAL; } if (vsi->offset < last_vsi_end_off || vsi->offset >= t->size) { btf_verifier_log_vsi(env, t, vsi, "Invalid offset"); return -EINVAL; } if (!vsi->size || vsi->size > t->size) { btf_verifier_log_vsi(env, t, vsi, "Invalid size"); return -EINVAL; } last_vsi_end_off = vsi->offset + vsi->size; if (last_vsi_end_off > t->size) { btf_verifier_log_vsi(env, t, vsi, "Invalid offset+size"); return -EINVAL; } btf_verifier_log_vsi(env, t, vsi, NULL); sum += vsi->size; } if (t->size < sum) { btf_verifier_log_type(env, t, "Invalid btf_info size"); return -EINVAL; } return meta_needed; } static int btf_datasec_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { const struct btf_var_secinfo *vsi; struct btf *btf = env->btf; u16 i; for_each_vsi_from(i, v->next_member, v->t, vsi) { u32 var_type_id = vsi->type, type_id, type_size = 0; const struct btf_type *var_type = btf_type_by_id(env->btf, var_type_id); if (!var_type || !btf_type_is_var(var_type)) { btf_verifier_log_vsi(env, v->t, vsi, "Not a VAR kind member"); return -EINVAL; } if (!env_type_is_resolve_sink(env, var_type) && !env_type_is_resolved(env, var_type_id)) { env_stack_set_next_member(env, i + 1); return env_stack_push(env, var_type, var_type_id); } type_id = var_type->type; if (!btf_type_id_size(btf, &type_id, &type_size)) { btf_verifier_log_vsi(env, v->t, vsi, "Invalid type"); return -EINVAL; } if (vsi->size < type_size) { btf_verifier_log_vsi(env, v->t, vsi, "Invalid size"); return -EINVAL; } } env_stack_pop_resolved(env, 0, 0); return 0; } static void btf_datasec_log(struct btf_verifier_env *env, const struct btf_type *t) { btf_verifier_log(env, "size=%u vlen=%u", t->size, btf_type_vlen(t)); } static void btf_datasec_seq_show(const struct btf *btf, const struct btf_type *t, u32 type_id, void *data, u8 bits_offset, struct seq_file *m) { const struct btf_var_secinfo *vsi; const struct btf_type *var; u32 i; seq_printf(m, "section (\"%s\") = {", __btf_name_by_offset(btf, t->name_off)); for_each_vsi(i, t, vsi) { var = btf_type_by_id(btf, vsi->type); if (i) seq_puts(m, ","); btf_type_ops(var)->seq_show(btf, var, vsi->type, data + vsi->offset, bits_offset, m); } seq_puts(m, "}"); } static const struct btf_kind_operations datasec_ops = { .check_meta = btf_datasec_check_meta, .resolve = btf_datasec_resolve, .check_member = btf_df_check_member, .check_kflag_member = btf_df_check_kflag_member, .log_details = btf_datasec_log, .seq_show = btf_datasec_seq_show, }; static int btf_func_proto_check(struct btf_verifier_env *env, const struct btf_type *t) { const struct btf_type *ret_type; const struct btf_param *args; const struct btf *btf; u16 nr_args, i; int err; btf = env->btf; args = (const struct btf_param *)(t + 1); nr_args = btf_type_vlen(t); /* Check func return type which could be "void" (t->type == 0) */ if (t->type) { u32 ret_type_id = t->type; ret_type = btf_type_by_id(btf, ret_type_id); if (!ret_type) { btf_verifier_log_type(env, t, "Invalid return type"); return -EINVAL; } if (btf_type_needs_resolve(ret_type) && !env_type_is_resolved(env, ret_type_id)) { err = btf_resolve(env, ret_type, ret_type_id); if (err) return err; } /* Ensure the return type is a type that has a size */ if (!btf_type_id_size(btf, &ret_type_id, NULL)) { btf_verifier_log_type(env, t, "Invalid return type"); return -EINVAL; } } if (!nr_args) return 0; /* Last func arg type_id could be 0 if it is a vararg */ if (!args[nr_args - 1].type) { if (args[nr_args - 1].name_off) { btf_verifier_log_type(env, t, "Invalid arg#%u", nr_args); return -EINVAL; } nr_args--; } err = 0; for (i = 0; i < nr_args; i++) { const struct btf_type *arg_type; u32 arg_type_id; arg_type_id = args[i].type; arg_type = btf_type_by_id(btf, arg_type_id); if (!arg_type) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); err = -EINVAL; break; } if (args[i].name_off && (!btf_name_offset_valid(btf, args[i].name_off) || !btf_name_valid_identifier(btf, args[i].name_off))) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); err = -EINVAL; break; } if (btf_type_needs_resolve(arg_type) && !env_type_is_resolved(env, arg_type_id)) { err = btf_resolve(env, arg_type, arg_type_id); if (err) break; } if (!btf_type_id_size(btf, &arg_type_id, NULL)) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); err = -EINVAL; break; } } return err; } static int btf_func_check(struct btf_verifier_env *env, const struct btf_type *t) { const struct btf_type *proto_type; const struct btf_param *args; const struct btf *btf; u16 nr_args, i; btf = env->btf; proto_type = btf_type_by_id(btf, t->type); if (!proto_type || !btf_type_is_func_proto(proto_type)) { btf_verifier_log_type(env, t, "Invalid type_id"); return -EINVAL; } args = (const struct btf_param *)(proto_type + 1); nr_args = btf_type_vlen(proto_type); for (i = 0; i < nr_args; i++) { if (!args[i].name_off && args[i].type) { btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); return -EINVAL; } } return 0; } static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { [BTF_KIND_INT] = &int_ops, [BTF_KIND_PTR] = &ptr_ops, [BTF_KIND_ARRAY] = &array_ops, [BTF_KIND_STRUCT] = &struct_ops, [BTF_KIND_UNION] = &struct_ops, [BTF_KIND_ENUM] = &enum_ops, [BTF_KIND_FWD] = &fwd_ops, [BTF_KIND_TYPEDEF] = &modifier_ops, [BTF_KIND_VOLATILE] = &modifier_ops, [BTF_KIND_CONST] = &modifier_ops, [BTF_KIND_RESTRICT] = &modifier_ops, [BTF_KIND_FUNC] = &func_ops, [BTF_KIND_FUNC_PROTO] = &func_proto_ops, [BTF_KIND_VAR] = &var_ops, [BTF_KIND_DATASEC] = &datasec_ops, }; static s32 btf_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) { u32 saved_meta_left = meta_left; s32 var_meta_size; if (meta_left < sizeof(*t)) { btf_verifier_log(env, "[%u] meta_left:%u meta_needed:%zu", env->log_type_id, meta_left, sizeof(*t)); return -EINVAL; } meta_left -= sizeof(*t); if (t->info & ~BTF_INFO_MASK) { btf_verifier_log(env, "[%u] Invalid btf_info:%x", env->log_type_id, t->info); return -EINVAL; } if (BTF_INFO_KIND(t->info) > BTF_KIND_MAX || BTF_INFO_KIND(t->info) == BTF_KIND_UNKN) { btf_verifier_log(env, "[%u] Invalid kind:%u", env->log_type_id, BTF_INFO_KIND(t->info)); return -EINVAL; } if (!btf_name_offset_valid(env->btf, t->name_off)) { btf_verifier_log(env, "[%u] Invalid name_offset:%u", env->log_type_id, t->name_off); return -EINVAL; } var_meta_size = btf_type_ops(t)->check_meta(env, t, meta_left); if (var_meta_size < 0) return var_meta_size; meta_left -= var_meta_size; return saved_meta_left - meta_left; } static int btf_check_all_metas(struct btf_verifier_env *env) { struct btf *btf = env->btf; struct btf_header *hdr; void *cur, *end; hdr = &btf->hdr; cur = btf->nohdr_data + hdr->type_off; end = cur + hdr->type_len; env->log_type_id = 1; while (cur < end) { struct btf_type *t = cur; s32 meta_size; meta_size = btf_check_meta(env, t, end - cur); if (meta_size < 0) return meta_size; btf_add_type(env, t); cur += meta_size; env->log_type_id++; } return 0; } static bool btf_resolve_valid(struct btf_verifier_env *env, const struct btf_type *t, u32 type_id) { struct btf *btf = env->btf; if (!env_type_is_resolved(env, type_id)) return false; if (btf_type_is_struct(t) || btf_type_is_datasec(t)) return !btf->resolved_ids[type_id] && !btf->resolved_sizes[type_id]; if (btf_type_is_modifier(t) || btf_type_is_ptr(t) || btf_type_is_var(t)) { t = btf_type_id_resolve(btf, &type_id); return t && !btf_type_is_modifier(t) && !btf_type_is_var(t) && !btf_type_is_datasec(t); } if (btf_type_is_array(t)) { const struct btf_array *array = btf_type_array(t); const struct btf_type *elem_type; u32 elem_type_id = array->type; u32 elem_size; elem_type = btf_type_id_size(btf, &elem_type_id, &elem_size); return elem_type && !btf_type_is_modifier(elem_type) && (array->nelems * elem_size == btf->resolved_sizes[type_id]); } return false; } static int btf_resolve(struct btf_verifier_env *env, const struct btf_type *t, u32 type_id) { u32 save_log_type_id = env->log_type_id; const struct resolve_vertex *v; int err = 0; env->resolve_mode = RESOLVE_TBD; env_stack_push(env, t, type_id); while (!err && (v = env_stack_peak(env))) { env->log_type_id = v->type_id; err = btf_type_ops(v->t)->resolve(env, v); } env->log_type_id = type_id; if (err == -E2BIG) { btf_verifier_log_type(env, t, "Exceeded max resolving depth:%u", MAX_RESOLVE_DEPTH); } else if (err == -EEXIST) { btf_verifier_log_type(env, t, "Loop detected"); } /* Final sanity check */ if (!err && !btf_resolve_valid(env, t, type_id)) { btf_verifier_log_type(env, t, "Invalid resolve state"); err = -EINVAL; } env->log_type_id = save_log_type_id; return err; } static int btf_check_all_types(struct btf_verifier_env *env) { struct btf *btf = env->btf; u32 type_id; int err; err = env_resolve_init(env); if (err) return err; env->phase++; for (type_id = 1; type_id <= btf->nr_types; type_id++) { const struct btf_type *t = btf_type_by_id(btf, type_id); env->log_type_id = type_id; if (btf_type_needs_resolve(t) && !env_type_is_resolved(env, type_id)) { err = btf_resolve(env, t, type_id); if (err) return err; } if (btf_type_is_func_proto(t)) { err = btf_func_proto_check(env, t); if (err) return err; } if (btf_type_is_func(t)) { err = btf_func_check(env, t); if (err) return err; } } return 0; } static int btf_parse_type_sec(struct btf_verifier_env *env) { const struct btf_header *hdr = &env->btf->hdr; int err; /* Type section must align to 4 bytes */ if (hdr->type_off & (sizeof(u32) - 1)) { btf_verifier_log(env, "Unaligned type_off"); return -EINVAL; } if (!hdr->type_len) { btf_verifier_log(env, "No type found"); return -EINVAL; } err = btf_check_all_metas(env); if (err) return err; return btf_check_all_types(env); } static int btf_parse_str_sec(struct btf_verifier_env *env) { const struct btf_header *hdr; struct btf *btf = env->btf; const char *start, *end; hdr = &btf->hdr; start = btf->nohdr_data + hdr->str_off; end = start + hdr->str_len; if (end != btf->data + btf->data_size) { btf_verifier_log(env, "String section is not at the end"); return -EINVAL; } if (!hdr->str_len || hdr->str_len - 1 > BTF_MAX_NAME_OFFSET || start[0] || end[-1]) { btf_verifier_log(env, "Invalid string section"); return -EINVAL; } btf->strings = start; return 0; } static const size_t btf_sec_info_offset[] = { offsetof(struct btf_header, type_off), offsetof(struct btf_header, str_off), }; static int btf_sec_info_cmp(const void *a, const void *b) { const struct btf_sec_info *x = a; const struct btf_sec_info *y = b; return (int)(x->off - y->off) ? : (int)(x->len - y->len); } static int btf_check_sec_info(struct btf_verifier_env *env, u32 btf_data_size) { struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)]; u32 total, expected_total, i; const struct btf_header *hdr; const struct btf *btf; btf = env->btf; hdr = &btf->hdr; /* Populate the secs from hdr */ for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) secs[i] = *(struct btf_sec_info *)((void *)hdr + btf_sec_info_offset[i]); sort(secs, ARRAY_SIZE(btf_sec_info_offset), sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL); /* Check for gaps and overlap among sections */ total = 0; expected_total = btf_data_size - hdr->hdr_len; for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) { if (expected_total < secs[i].off) { btf_verifier_log(env, "Invalid section offset"); return -EINVAL; } if (total < secs[i].off) { /* gap */ btf_verifier_log(env, "Unsupported section found"); return -EINVAL; } if (total > secs[i].off) { btf_verifier_log(env, "Section overlap found"); return -EINVAL; } if (expected_total - total < secs[i].len) { btf_verifier_log(env, "Total section length too long"); return -EINVAL; } total += secs[i].len; } /* There is data other than hdr and known sections */ if (expected_total != total) { btf_verifier_log(env, "Unsupported section found"); return -EINVAL; } return 0; } static int btf_parse_hdr(struct btf_verifier_env *env) { u32 hdr_len, hdr_copy, btf_data_size; const struct btf_header *hdr; struct btf *btf; int err; btf = env->btf; btf_data_size = btf->data_size; if (btf_data_size < offsetof(struct btf_header, hdr_len) + sizeof(hdr->hdr_len)) { btf_verifier_log(env, "hdr_len not found"); return -EINVAL; } hdr = btf->data; hdr_len = hdr->hdr_len; if (btf_data_size < hdr_len) { btf_verifier_log(env, "btf_header not found"); return -EINVAL; } /* Ensure the unsupported header fields are zero */ if (hdr_len > sizeof(btf->hdr)) { u8 *expected_zero = btf->data + sizeof(btf->hdr); u8 *end = btf->data + hdr_len; for (; expected_zero < end; expected_zero++) { if (*expected_zero) { btf_verifier_log(env, "Unsupported btf_header"); return -E2BIG; } } } hdr_copy = min_t(u32, hdr_len, sizeof(btf->hdr)); memcpy(&btf->hdr, btf->data, hdr_copy); hdr = &btf->hdr; btf_verifier_log_hdr(env, btf_data_size); if (hdr->magic != BTF_MAGIC) { btf_verifier_log(env, "Invalid magic"); return -EINVAL; } if (hdr->version != BTF_VERSION) { btf_verifier_log(env, "Unsupported version"); return -ENOTSUPP; } if (hdr->flags) { btf_verifier_log(env, "Unsupported flags"); return -ENOTSUPP; } if (btf_data_size == hdr->hdr_len) { btf_verifier_log(env, "No data"); return -EINVAL; } err = btf_check_sec_info(env, btf_data_size); if (err) return err; return 0; } static struct btf *btf_parse(void __user *btf_data, u32 btf_data_size, u32 log_level, char __user *log_ubuf, u32 log_size) { struct btf_verifier_env *env = NULL; struct bpf_verifier_log *log; struct btf *btf = NULL; u8 *data; int err; if (btf_data_size > BTF_MAX_SIZE) return ERR_PTR(-E2BIG); env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); if (!env) return ERR_PTR(-ENOMEM); log = &env->log; if (log_level || log_ubuf || log_size) { /* user requested verbose verifier output * and supplied buffer to store the verification trace */ log->level = log_level; log->ubuf = log_ubuf; log->len_total = log_size; /* log attributes have to be sane */ if (log->len_total < 128 || log->len_total > UINT_MAX >> 8 || !log->level || !log->ubuf) { err = -EINVAL; goto errout; } } btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); if (!btf) { err = -ENOMEM; goto errout; } env->btf = btf; data = kvmalloc(btf_data_size, GFP_KERNEL | __GFP_NOWARN); if (!data) { err = -ENOMEM; goto errout; } btf->data = data; btf->data_size = btf_data_size; if (copy_from_user(data, btf_data, btf_data_size)) { err = -EFAULT; goto errout; } err = btf_parse_hdr(env); if (err) goto errout; btf->nohdr_data = btf->data + btf->hdr.hdr_len; err = btf_parse_str_sec(env); if (err) goto errout; err = btf_parse_type_sec(env); if (err) goto errout; if (log->level && bpf_verifier_log_full(log)) { err = -ENOSPC; goto errout; } btf_verifier_env_free(env); refcount_set(&btf->refcnt, 1); return btf; errout: btf_verifier_env_free(env); if (btf) btf_free(btf); return ERR_PTR(err); } extern char __weak _binary__btf_vmlinux_bin_start[]; extern char __weak _binary__btf_vmlinux_bin_end[]; extern struct btf *btf_vmlinux; #define BPF_MAP_TYPE(_id, _ops) static union { struct bpf_ctx_convert { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ prog_ctx_type _id##_prog; \ kern_ctx_type _id##_kern; #include #undef BPF_PROG_TYPE } *__t; /* 't' is written once under lock. Read many times. */ const struct btf_type *t; } bpf_ctx_convert; enum { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ __ctx_convert##_id, #include #undef BPF_PROG_TYPE __ctx_convert_unused, /* to avoid empty enum in extreme .config */ }; static u8 bpf_ctx_convert_map[] = { #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \ [_id] = __ctx_convert##_id, #include #undef BPF_PROG_TYPE 0, /* avoid empty array */ }; #undef BPF_MAP_TYPE static const struct btf_member * btf_get_prog_ctx_type(struct bpf_verifier_log *log, struct btf *btf, const struct btf_type *t, enum bpf_prog_type prog_type, int arg) { const struct btf_type *conv_struct; const struct btf_type *ctx_struct; const struct btf_member *ctx_type; const char *tname, *ctx_tname; conv_struct = bpf_ctx_convert.t; if (!conv_struct) { bpf_log(log, "btf_vmlinux is malformed\n"); return NULL; } t = btf_type_by_id(btf, t->type); while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (!btf_type_is_struct(t)) { /* Only pointer to struct is supported for now. * That means that BPF_PROG_TYPE_TRACEPOINT with BTF * is not supported yet. * BPF_PROG_TYPE_RAW_TRACEPOINT is fine. */ if (log->level & BPF_LOG_LEVEL) bpf_log(log, "arg#%d type is not a struct\n", arg); return NULL; } tname = btf_name_by_offset(btf, t->name_off); if (!tname) { bpf_log(log, "arg#%d struct doesn't have a name\n", arg); return NULL; } /* prog_type is valid bpf program type. No need for bounds check. */ ctx_type = btf_type_member(conv_struct) + bpf_ctx_convert_map[prog_type] * 2; /* ctx_struct is a pointer to prog_ctx_type in vmlinux. * Like 'struct __sk_buff' */ ctx_struct = btf_type_by_id(btf_vmlinux, ctx_type->type); if (!ctx_struct) /* should not happen */ return NULL; ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_struct->name_off); if (!ctx_tname) { /* should not happen */ bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n"); return NULL; } /* only compare that prog's ctx type name is the same as * kernel expects. No need to compare field by field. * It's ok for bpf prog to do: * struct __sk_buff {}; * int socket_filter_bpf_prog(struct __sk_buff *skb) * { // no fields of skb are ever used } */ if (strcmp(ctx_tname, tname)) return NULL; return ctx_type; } static int btf_translate_to_vmlinux(struct bpf_verifier_log *log, struct btf *btf, const struct btf_type *t, enum bpf_prog_type prog_type, int arg) { const struct btf_member *prog_ctx_type, *kern_ctx_type; prog_ctx_type = btf_get_prog_ctx_type(log, btf, t, prog_type, arg); if (!prog_ctx_type) return -ENOENT; kern_ctx_type = prog_ctx_type + 1; return kern_ctx_type->type; } struct btf *btf_parse_vmlinux(void) { struct btf_verifier_env *env = NULL; struct bpf_verifier_log *log; struct btf *btf = NULL; int err, i; env = kzalloc(sizeof(*env), GFP_KERNEL | __GFP_NOWARN); if (!env) return ERR_PTR(-ENOMEM); log = &env->log; log->level = BPF_LOG_KERNEL; btf = kzalloc(sizeof(*btf), GFP_KERNEL | __GFP_NOWARN); if (!btf) { err = -ENOMEM; goto errout; } env->btf = btf; btf->data = _binary__btf_vmlinux_bin_start; btf->data_size = _binary__btf_vmlinux_bin_end - _binary__btf_vmlinux_bin_start; err = btf_parse_hdr(env); if (err) goto errout; btf->nohdr_data = btf->data + btf->hdr.hdr_len; err = btf_parse_str_sec(env); if (err) goto errout; err = btf_check_all_metas(env); if (err) goto errout; /* find struct bpf_ctx_convert for type checking later */ for (i = 1; i <= btf->nr_types; i++) { const struct btf_type *t; const char *tname; t = btf_type_by_id(btf, i); if (!__btf_type_is_struct(t)) continue; tname = __btf_name_by_offset(btf, t->name_off); if (!strcmp(tname, "bpf_ctx_convert")) { /* btf_parse_vmlinux() runs under bpf_verifier_lock */ bpf_ctx_convert.t = t; break; } } if (i > btf->nr_types) { err = -ENOENT; goto errout; } bpf_struct_ops_init(btf, log); btf_verifier_env_free(env); refcount_set(&btf->refcnt, 1); return btf; errout: btf_verifier_env_free(env); if (btf) { kvfree(btf->types); kfree(btf); } return ERR_PTR(err); } struct btf *bpf_prog_get_target_btf(const struct bpf_prog *prog) { struct bpf_prog *tgt_prog = prog->aux->linked_prog; if (tgt_prog) { return tgt_prog->aux->btf; } else { return btf_vmlinux; } } static bool is_string_ptr(struct btf *btf, const struct btf_type *t) { /* t comes in already as a pointer */ t = btf_type_by_id(btf, t->type); /* allow const */ if (BTF_INFO_KIND(t->info) == BTF_KIND_CONST) t = btf_type_by_id(btf, t->type); /* char, signed char, unsigned char */ return btf_type_is_int(t) && t->size == 1; } bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { const struct btf_type *t = prog->aux->attach_func_proto; struct bpf_prog *tgt_prog = prog->aux->linked_prog; struct btf *btf = bpf_prog_get_target_btf(prog); const char *tname = prog->aux->attach_func_name; struct bpf_verifier_log *log = info->log; const struct btf_param *args; u32 nr_args, arg; int ret; if (off % 8) { bpf_log(log, "func '%s' offset %d is not multiple of 8\n", tname, off); return false; } arg = off / 8; args = (const struct btf_param *)(t + 1); /* if (t == NULL) Fall back to default BPF prog with 5 u64 arguments */ nr_args = t ? btf_type_vlen(t) : 5; if (prog->aux->attach_btf_trace) { /* skip first 'void *__data' argument in btf_trace_##name typedef */ args++; nr_args--; } if ((prog->expected_attach_type == BPF_TRACE_FEXIT || prog->expected_attach_type == BPF_MODIFY_RETURN) && arg == nr_args) { if (!t) /* Default prog with 5 args. 6th arg is retval. */ return true; /* function return type */ t = btf_type_by_id(btf, t->type); } else if (arg >= nr_args) { bpf_log(log, "func '%s' doesn't have %d-th argument\n", tname, arg + 1); return false; } else { if (!t) /* Default prog with 5 args */ return true; t = btf_type_by_id(btf, args[arg].type); } /* skip modifiers */ while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (btf_type_is_int(t) || btf_type_is_enum(t)) /* accessing a scalar */ return true; if (!btf_type_is_ptr(t)) { bpf_log(log, "func '%s' arg%d '%s' has type %s. Only pointer access is allowed\n", tname, arg, __btf_name_by_offset(btf, t->name_off), btf_kind_str[BTF_INFO_KIND(t->info)]); return false; } if (t->type == 0) /* This is a pointer to void. * It is the same as scalar from the verifier safety pov. * No further pointer walking is allowed. */ return true; if (is_string_ptr(btf, t)) return true; /* this is a pointer to another type */ info->reg_type = PTR_TO_BTF_ID; if (tgt_prog) { ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type, arg); if (ret > 0) { info->btf_id = ret; return true; } else { return false; } } info->btf_id = t->type; t = btf_type_by_id(btf, t->type); /* skip modifiers */ while (btf_type_is_modifier(t)) { info->btf_id = t->type; t = btf_type_by_id(btf, t->type); } if (!btf_type_is_struct(t)) { bpf_log(log, "func '%s' arg%d type %s is not a struct\n", tname, arg, btf_kind_str[BTF_INFO_KIND(t->info)]); return false; } bpf_log(log, "func '%s' arg%d has btf_id %d type %s '%s'\n", tname, arg, info->btf_id, btf_kind_str[BTF_INFO_KIND(t->info)], __btf_name_by_offset(btf, t->name_off)); return true; } int btf_struct_access(struct bpf_verifier_log *log, const struct btf_type *t, int off, int size, enum bpf_access_type atype, u32 *next_btf_id) { u32 i, moff, mtrue_end, msize = 0, total_nelems = 0; const struct btf_type *mtype, *elem_type = NULL; const struct btf_member *member; const char *tname, *mname; again: tname = __btf_name_by_offset(btf_vmlinux, t->name_off); if (!btf_type_is_struct(t)) { bpf_log(log, "Type '%s' is not a struct\n", tname); return -EINVAL; } if (off + size > t->size) { bpf_log(log, "access beyond struct %s at off %u size %u\n", tname, off, size); return -EACCES; } for_each_member(i, t, member) { /* offset of the field in bytes */ moff = btf_member_bit_offset(t, member) / 8; if (off + size <= moff) /* won't find anything, field is already too far */ break; if (btf_member_bitfield_size(t, member)) { u32 end_bit = btf_member_bit_offset(t, member) + btf_member_bitfield_size(t, member); /* off <= moff instead of off == moff because clang * does not generate a BTF member for anonymous * bitfield like the ":16" here: * struct { * int :16; * int x:8; * }; */ if (off <= moff && BITS_ROUNDUP_BYTES(end_bit) <= off + size) return SCALAR_VALUE; /* off may be accessing a following member * * or * * Doing partial access at either end of this * bitfield. Continue on this case also to * treat it as not accessing this bitfield * and eventually error out as field not * found to keep it simple. * It could be relaxed if there was a legit * partial access case later. */ continue; } /* In case of "off" is pointing to holes of a struct */ if (off < moff) break; /* type of the field */ mtype = btf_type_by_id(btf_vmlinux, member->type); mname = __btf_name_by_offset(btf_vmlinux, member->name_off); mtype = btf_resolve_size(btf_vmlinux, mtype, &msize, &elem_type, &total_nelems); if (IS_ERR(mtype)) { bpf_log(log, "field %s doesn't have size\n", mname); return -EFAULT; } mtrue_end = moff + msize; if (off >= mtrue_end) /* no overlap with member, keep iterating */ continue; if (btf_type_is_array(mtype)) { u32 elem_idx; /* btf_resolve_size() above helps to * linearize a multi-dimensional array. * * The logic here is treating an array * in a struct as the following way: * * struct outer { * struct inner array[2][2]; * }; * * looks like: * * struct outer { * struct inner array_elem0; * struct inner array_elem1; * struct inner array_elem2; * struct inner array_elem3; * }; * * When accessing outer->array[1][0], it moves * moff to "array_elem2", set mtype to * "struct inner", and msize also becomes * sizeof(struct inner). Then most of the * remaining logic will fall through without * caring the current member is an array or * not. * * Unlike mtype/msize/moff, mtrue_end does not * change. The naming difference ("_true") tells * that it is not always corresponding to * the current mtype/msize/moff. * It is the true end of the current * member (i.e. array in this case). That * will allow an int array to be accessed like * a scratch space, * i.e. allow access beyond the size of * the array's element as long as it is * within the mtrue_end boundary. */ /* skip empty array */ if (moff == mtrue_end) continue; msize /= total_nelems; elem_idx = (off - moff) / msize; moff += elem_idx * msize; mtype = elem_type; } /* the 'off' we're looking for is either equal to start * of this field or inside of this struct */ if (btf_type_is_struct(mtype)) { /* our field must be inside that union or struct */ t = mtype; /* adjust offset we're looking for */ off -= moff; goto again; } if (btf_type_is_ptr(mtype)) { const struct btf_type *stype; u32 id; if (msize != size || off != moff) { bpf_log(log, "cannot access ptr member %s with moff %u in struct %s with off %u size %u\n", mname, moff, tname, off, size); return -EACCES; } stype = btf_type_skip_modifiers(btf_vmlinux, mtype->type, &id); if (btf_type_is_struct(stype)) { *next_btf_id = id; return PTR_TO_BTF_ID; } } /* Allow more flexible access within an int as long as * it is within mtrue_end. * Since mtrue_end could be the end of an array, * that also allows using an array of int as a scratch * space. e.g. skb->cb[]. */ if (off + size > mtrue_end) { bpf_log(log, "access beyond the end of member %s (mend:%u) in struct %s with off %u size %u\n", mname, mtrue_end, tname, off, size); return -EACCES; } return SCALAR_VALUE; } bpf_log(log, "struct %s doesn't have field at offset %d\n", tname, off); return -EINVAL; } static int __btf_resolve_helper_id(struct bpf_verifier_log *log, void *fn, int arg) { char fnname[KSYM_SYMBOL_LEN + 4] = "btf_"; const struct btf_param *args; const struct btf_type *t; const char *tname, *sym; u32 btf_id, i; if (IS_ERR(btf_vmlinux)) { bpf_log(log, "btf_vmlinux is malformed\n"); return -EINVAL; } sym = kallsyms_lookup((long)fn, NULL, NULL, NULL, fnname + 4); if (!sym) { bpf_log(log, "kernel doesn't have kallsyms\n"); return -EFAULT; } for (i = 1; i <= btf_vmlinux->nr_types; i++) { t = btf_type_by_id(btf_vmlinux, i); if (BTF_INFO_KIND(t->info) != BTF_KIND_TYPEDEF) continue; tname = __btf_name_by_offset(btf_vmlinux, t->name_off); if (!strcmp(tname, fnname)) break; } if (i > btf_vmlinux->nr_types) { bpf_log(log, "helper %s type is not found\n", fnname); return -ENOENT; } t = btf_type_by_id(btf_vmlinux, t->type); if (!btf_type_is_ptr(t)) return -EFAULT; t = btf_type_by_id(btf_vmlinux, t->type); if (!btf_type_is_func_proto(t)) return -EFAULT; args = (const struct btf_param *)(t + 1); if (arg >= btf_type_vlen(t)) { bpf_log(log, "bpf helper %s doesn't have %d-th argument\n", fnname, arg); return -EINVAL; } t = btf_type_by_id(btf_vmlinux, args[arg].type); if (!btf_type_is_ptr(t) || !t->type) { /* anything but the pointer to struct is a helper config bug */ bpf_log(log, "ARG_PTR_TO_BTF is misconfigured\n"); return -EFAULT; } btf_id = t->type; t = btf_type_by_id(btf_vmlinux, t->type); /* skip modifiers */ while (btf_type_is_modifier(t)) { btf_id = t->type; t = btf_type_by_id(btf_vmlinux, t->type); } if (!btf_type_is_struct(t)) { bpf_log(log, "ARG_PTR_TO_BTF is not a struct\n"); return -EFAULT; } bpf_log(log, "helper %s arg%d has btf_id %d struct %s\n", fnname + 4, arg, btf_id, __btf_name_by_offset(btf_vmlinux, t->name_off)); return btf_id; } int btf_resolve_helper_id(struct bpf_verifier_log *log, const struct bpf_func_proto *fn, int arg) { int *btf_id = &fn->btf_id[arg]; int ret; if (fn->arg_type[arg] != ARG_PTR_TO_BTF_ID) return -EINVAL; ret = READ_ONCE(*btf_id); if (ret) return ret; /* ok to race the search. The result is the same */ ret = __btf_resolve_helper_id(log, fn->func, arg); if (!ret) { /* Function argument cannot be type 'void' */ bpf_log(log, "BTF resolution bug\n"); return -EFAULT; } WRITE_ONCE(*btf_id, ret); return ret; } static int __get_type_size(struct btf *btf, u32 btf_id, const struct btf_type **bad_type) { const struct btf_type *t; if (!btf_id) /* void */ return 0; t = btf_type_by_id(btf, btf_id); while (t && btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (!t) { *bad_type = btf->types[0]; return -EINVAL; } if (btf_type_is_ptr(t)) /* kernel size of pointer. Not BPF's size of pointer*/ return sizeof(void *); if (btf_type_is_int(t) || btf_type_is_enum(t)) return t->size; *bad_type = t; return -EINVAL; } int btf_distill_func_proto(struct bpf_verifier_log *log, struct btf *btf, const struct btf_type *func, const char *tname, struct btf_func_model *m) { const struct btf_param *args; const struct btf_type *t; u32 i, nargs; int ret; if (!func) { /* BTF function prototype doesn't match the verifier types. * Fall back to 5 u64 args. */ for (i = 0; i < 5; i++) m->arg_size[i] = 8; m->ret_size = 8; m->nr_args = 5; return 0; } args = (const struct btf_param *)(func + 1); nargs = btf_type_vlen(func); if (nargs >= MAX_BPF_FUNC_ARGS) { bpf_log(log, "The function %s has %d arguments. Too many.\n", tname, nargs); return -EINVAL; } ret = __get_type_size(btf, func->type, &t); if (ret < 0) { bpf_log(log, "The function %s return type %s is unsupported.\n", tname, btf_kind_str[BTF_INFO_KIND(t->info)]); return -EINVAL; } m->ret_size = ret; for (i = 0; i < nargs; i++) { ret = __get_type_size(btf, args[i].type, &t); if (ret < 0) { bpf_log(log, "The function %s arg%d type %s is unsupported.\n", tname, i, btf_kind_str[BTF_INFO_KIND(t->info)]); return -EINVAL; } m->arg_size[i] = ret; } m->nr_args = nargs; return 0; } /* Compare BTFs of two functions assuming only scalars and pointers to context. * t1 points to BTF_KIND_FUNC in btf1 * t2 points to BTF_KIND_FUNC in btf2 * Returns: * EINVAL - function prototype mismatch * EFAULT - verifier bug * 0 - 99% match. The last 1% is validated by the verifier. */ static int btf_check_func_type_match(struct bpf_verifier_log *log, struct btf *btf1, const struct btf_type *t1, struct btf *btf2, const struct btf_type *t2) { const struct btf_param *args1, *args2; const char *fn1, *fn2, *s1, *s2; u32 nargs1, nargs2, i; fn1 = btf_name_by_offset(btf1, t1->name_off); fn2 = btf_name_by_offset(btf2, t2->name_off); if (btf_func_linkage(t1) != BTF_FUNC_GLOBAL) { bpf_log(log, "%s() is not a global function\n", fn1); return -EINVAL; } if (btf_func_linkage(t2) != BTF_FUNC_GLOBAL) { bpf_log(log, "%s() is not a global function\n", fn2); return -EINVAL; } t1 = btf_type_by_id(btf1, t1->type); if (!t1 || !btf_type_is_func_proto(t1)) return -EFAULT; t2 = btf_type_by_id(btf2, t2->type); if (!t2 || !btf_type_is_func_proto(t2)) return -EFAULT; args1 = (const struct btf_param *)(t1 + 1); nargs1 = btf_type_vlen(t1); args2 = (const struct btf_param *)(t2 + 1); nargs2 = btf_type_vlen(t2); if (nargs1 != nargs2) { bpf_log(log, "%s() has %d args while %s() has %d args\n", fn1, nargs1, fn2, nargs2); return -EINVAL; } t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); if (t1->info != t2->info) { bpf_log(log, "Return type %s of %s() doesn't match type %s of %s()\n", btf_type_str(t1), fn1, btf_type_str(t2), fn2); return -EINVAL; } for (i = 0; i < nargs1; i++) { t1 = btf_type_skip_modifiers(btf1, args1[i].type, NULL); t2 = btf_type_skip_modifiers(btf2, args2[i].type, NULL); if (t1->info != t2->info) { bpf_log(log, "arg%d in %s() is %s while %s() has %s\n", i, fn1, btf_type_str(t1), fn2, btf_type_str(t2)); return -EINVAL; } if (btf_type_has_size(t1) && t1->size != t2->size) { bpf_log(log, "arg%d in %s() has size %d while %s() has %d\n", i, fn1, t1->size, fn2, t2->size); return -EINVAL; } /* global functions are validated with scalars and pointers * to context only. And only global functions can be replaced. * Hence type check only those types. */ if (btf_type_is_int(t1) || btf_type_is_enum(t1)) continue; if (!btf_type_is_ptr(t1)) { bpf_log(log, "arg%d in %s() has unrecognized type\n", i, fn1); return -EINVAL; } t1 = btf_type_skip_modifiers(btf1, t1->type, NULL); t2 = btf_type_skip_modifiers(btf2, t2->type, NULL); if (!btf_type_is_struct(t1)) { bpf_log(log, "arg%d in %s() is not a pointer to context\n", i, fn1); return -EINVAL; } if (!btf_type_is_struct(t2)) { bpf_log(log, "arg%d in %s() is not a pointer to context\n", i, fn2); return -EINVAL; } /* This is an optional check to make program writing easier. * Compare names of structs and report an error to the user. * btf_prepare_func_args() already checked that t2 struct * is a context type. btf_prepare_func_args() will check * later that t1 struct is a context type as well. */ s1 = btf_name_by_offset(btf1, t1->name_off); s2 = btf_name_by_offset(btf2, t2->name_off); if (strcmp(s1, s2)) { bpf_log(log, "arg%d %s(struct %s *) doesn't match %s(struct %s *)\n", i, fn1, s1, fn2, s2); return -EINVAL; } } return 0; } /* Compare BTFs of given program with BTF of target program */ int btf_check_type_match(struct bpf_verifier_env *env, struct bpf_prog *prog, struct btf *btf2, const struct btf_type *t2) { struct btf *btf1 = prog->aux->btf; const struct btf_type *t1; u32 btf_id = 0; if (!prog->aux->func_info) { bpf_log(&env->log, "Program extension requires BTF\n"); return -EINVAL; } btf_id = prog->aux->func_info[0].type_id; if (!btf_id) return -EFAULT; t1 = btf_type_by_id(btf1, btf_id); if (!t1 || !btf_type_is_func(t1)) return -EFAULT; return btf_check_func_type_match(&env->log, btf1, t1, btf2, t2); } /* Compare BTF of a function with given bpf_reg_state. * Returns: * EFAULT - there is a verifier bug. Abort verification. * EINVAL - there is a type mismatch or BTF is not available. * 0 - BTF matches with what bpf_reg_state expects. * Only PTR_TO_CTX and SCALAR_VALUE states are recognized. */ int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *reg) { struct bpf_verifier_log *log = &env->log; struct bpf_prog *prog = env->prog; struct btf *btf = prog->aux->btf; const struct btf_param *args; const struct btf_type *t; u32 i, nargs, btf_id; const char *tname; if (!prog->aux->func_info) return -EINVAL; btf_id = prog->aux->func_info[subprog].type_id; if (!btf_id) return -EFAULT; if (prog->aux->func_info_aux[subprog].unreliable) return -EINVAL; t = btf_type_by_id(btf, btf_id); if (!t || !btf_type_is_func(t)) { /* These checks were already done by the verifier while loading * struct bpf_func_info */ bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n", subprog); return -EFAULT; } tname = btf_name_by_offset(btf, t->name_off); t = btf_type_by_id(btf, t->type); if (!t || !btf_type_is_func_proto(t)) { bpf_log(log, "Invalid BTF of func %s\n", tname); return -EFAULT; } args = (const struct btf_param *)(t + 1); nargs = btf_type_vlen(t); if (nargs > 5) { bpf_log(log, "Function %s has %d > 5 args\n", tname, nargs); goto out; } /* check that BTF function arguments match actual types that the * verifier sees. */ for (i = 0; i < nargs; i++) { t = btf_type_by_id(btf, args[i].type); while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (btf_type_is_int(t) || btf_type_is_enum(t)) { if (reg[i + 1].type == SCALAR_VALUE) continue; bpf_log(log, "R%d is not a scalar\n", i + 1); goto out; } if (btf_type_is_ptr(t)) { if (reg[i + 1].type == SCALAR_VALUE) { bpf_log(log, "R%d is not a pointer\n", i + 1); goto out; } /* If function expects ctx type in BTF check that caller * is passing PTR_TO_CTX. */ if (btf_get_prog_ctx_type(log, btf, t, prog->type, i)) { if (reg[i + 1].type != PTR_TO_CTX) { bpf_log(log, "arg#%d expected pointer to ctx, but got %s\n", i, btf_kind_str[BTF_INFO_KIND(t->info)]); goto out; } if (check_ctx_reg(env, ®[i + 1], i + 1)) goto out; continue; } } bpf_log(log, "Unrecognized arg#%d type %s\n", i, btf_kind_str[BTF_INFO_KIND(t->info)]); goto out; } return 0; out: /* Compiler optimizations can remove arguments from static functions * or mismatched type can be passed into a global function. * In such cases mark the function as unreliable from BTF point of view. */ prog->aux->func_info_aux[subprog].unreliable = true; return -EINVAL; } /* Convert BTF of a function into bpf_reg_state if possible * Returns: * EFAULT - there is a verifier bug. Abort verification. * EINVAL - cannot convert BTF. * 0 - Successfully converted BTF into bpf_reg_state * (either PTR_TO_CTX or SCALAR_VALUE). */ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, struct bpf_reg_state *reg) { struct bpf_verifier_log *log = &env->log; struct bpf_prog *prog = env->prog; enum bpf_prog_type prog_type = prog->type; struct btf *btf = prog->aux->btf; const struct btf_param *args; const struct btf_type *t; u32 i, nargs, btf_id; const char *tname; if (!prog->aux->func_info || prog->aux->func_info_aux[subprog].linkage != BTF_FUNC_GLOBAL) { bpf_log(log, "Verifier bug\n"); return -EFAULT; } btf_id = prog->aux->func_info[subprog].type_id; if (!btf_id) { bpf_log(log, "Global functions need valid BTF\n"); return -EFAULT; } t = btf_type_by_id(btf, btf_id); if (!t || !btf_type_is_func(t)) { /* These checks were already done by the verifier while loading * struct bpf_func_info */ bpf_log(log, "BTF of func#%d doesn't point to KIND_FUNC\n", subprog); return -EFAULT; } tname = btf_name_by_offset(btf, t->name_off); if (log->level & BPF_LOG_LEVEL) bpf_log(log, "Validating %s() func#%d...\n", tname, subprog); if (prog->aux->func_info_aux[subprog].unreliable) { bpf_log(log, "Verifier bug in function %s()\n", tname); return -EFAULT; } if (prog_type == BPF_PROG_TYPE_EXT) prog_type = prog->aux->linked_prog->type; t = btf_type_by_id(btf, t->type); if (!t || !btf_type_is_func_proto(t)) { bpf_log(log, "Invalid type of function %s()\n", tname); return -EFAULT; } args = (const struct btf_param *)(t + 1); nargs = btf_type_vlen(t); if (nargs > 5) { bpf_log(log, "Global function %s() with %d > 5 args. Buggy compiler.\n", tname, nargs); return -EINVAL; } /* check that function returns int */ t = btf_type_by_id(btf, t->type); while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (!btf_type_is_int(t) && !btf_type_is_enum(t)) { bpf_log(log, "Global function %s() doesn't return scalar. Only those are supported.\n", tname); return -EINVAL; } /* Convert BTF function arguments into verifier types. * Only PTR_TO_CTX and SCALAR are supported atm. */ for (i = 0; i < nargs; i++) { t = btf_type_by_id(btf, args[i].type); while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (btf_type_is_int(t) || btf_type_is_enum(t)) { reg[i + 1].type = SCALAR_VALUE; continue; } if (btf_type_is_ptr(t) && btf_get_prog_ctx_type(log, btf, t, prog_type, i)) { reg[i + 1].type = PTR_TO_CTX; continue; } bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n", i, btf_kind_str[BTF_INFO_KIND(t->info)], tname); return -EINVAL; } return 0; } void btf_type_seq_show(const struct btf *btf, u32 type_id, void *obj, struct seq_file *m) { const struct btf_type *t = btf_type_by_id(btf, type_id); btf_type_ops(t)->seq_show(btf, t, type_id, obj, 0, m); } #ifdef CONFIG_PROC_FS static void bpf_btf_show_fdinfo(struct seq_file *m, struct file *filp) { const struct btf *btf = filp->private_data; seq_printf(m, "btf_id:\t%u\n", btf->id); } #endif static int btf_release(struct inode *inode, struct file *filp) { btf_put(filp->private_data); return 0; } const struct file_operations btf_fops = { #ifdef CONFIG_PROC_FS .show_fdinfo = bpf_btf_show_fdinfo, #endif .release = btf_release, }; static int __btf_new_fd(struct btf *btf) { return anon_inode_getfd("btf", &btf_fops, btf, O_RDONLY | O_CLOEXEC); } int btf_new_fd(const union bpf_attr *attr) { struct btf *btf; int ret; btf = btf_parse(u64_to_user_ptr(attr->btf), attr->btf_size, attr->btf_log_level, u64_to_user_ptr(attr->btf_log_buf), attr->btf_log_size); if (IS_ERR(btf)) return PTR_ERR(btf); ret = btf_alloc_id(btf); if (ret) { btf_free(btf); return ret; } /* * The BTF ID is published to the userspace. * All BTF free must go through call_rcu() from * now on (i.e. free by calling btf_put()). */ ret = __btf_new_fd(btf); if (ret < 0) btf_put(btf); return ret; } struct btf *btf_get_by_fd(int fd) { struct btf *btf; struct fd f; f = fdget(fd); if (!f.file) return ERR_PTR(-EBADF); if (f.file->f_op != &btf_fops) { fdput(f); return ERR_PTR(-EINVAL); } btf = f.file->private_data; refcount_inc(&btf->refcnt); fdput(f); return btf; } int btf_get_info_by_fd(const struct btf *btf, const union bpf_attr *attr, union bpf_attr __user *uattr) { struct bpf_btf_info __user *uinfo; struct bpf_btf_info info = {}; u32 info_copy, btf_copy; void __user *ubtf; u32 uinfo_len; uinfo = u64_to_user_ptr(attr->info.info); uinfo_len = attr->info.info_len; info_copy = min_t(u32, uinfo_len, sizeof(info)); if (copy_from_user(&info, uinfo, info_copy)) return -EFAULT; info.id = btf->id; ubtf = u64_to_user_ptr(info.btf); btf_copy = min_t(u32, btf->data_size, info.btf_size); if (copy_to_user(ubtf, btf->data, btf_copy)) return -EFAULT; info.btf_size = btf->data_size; if (copy_to_user(uinfo, &info, info_copy) || put_user(info_copy, &uattr->info.info_len)) return -EFAULT; return 0; } int btf_get_fd_by_id(u32 id) { struct btf *btf; int fd; rcu_read_lock(); btf = idr_find(&btf_idr, id); if (!btf || !refcount_inc_not_zero(&btf->refcnt)) btf = ERR_PTR(-ENOENT); rcu_read_unlock(); if (IS_ERR(btf)) return PTR_ERR(btf); fd = __btf_new_fd(btf); if (fd < 0) btf_put(btf); return fd; } u32 btf_id(const struct btf *btf) { return btf->id; }