diff options
Diffstat (limited to 'kernel/bpf/btf.c')
-rw-r--r-- | kernel/bpf/btf.c | 275 |
1 files changed, 209 insertions, 66 deletions
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index edef96ceffa3..6ff0bd1a91d5 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -1699,6 +1699,13 @@ static void btf_free_struct_meta_tab(struct btf *btf) static void btf_free_struct_ops_tab(struct btf *btf) { struct btf_struct_ops_tab *tab = btf->struct_ops_tab; + u32 i; + + if (!tab) + return; + + for (i = 0; i < tab->cnt; i++) + bpf_struct_ops_desc_release(&tab->ops[i]); kfree(tab); btf->struct_ops_tab = NULL; @@ -5687,15 +5694,29 @@ static int find_kern_ctx_type_id(enum bpf_prog_type prog_type) return ctx_type->type; } -const struct btf_type * -btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, - const struct btf_type *t, enum bpf_prog_type prog_type, - int arg) +bool btf_is_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, + const struct btf_type *t, enum bpf_prog_type prog_type, + int arg) { const struct btf_type *ctx_type; const char *tname, *ctx_tname; t = btf_type_by_id(btf, t->type); + + /* KPROBE programs allow bpf_user_pt_regs_t typedef, which we need to + * check before we skip all the typedef below. + */ + if (prog_type == BPF_PROG_TYPE_KPROBE) { + while (btf_type_is_modifier(t) && !btf_type_is_typedef(t)) + t = btf_type_by_id(btf, t->type); + + if (btf_type_is_typedef(t)) { + tname = btf_name_by_offset(btf, t->name_off); + if (tname && strcmp(tname, "bpf_user_pt_regs_t") == 0) + return true; + } + } + while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (!btf_type_is_struct(t)) { @@ -5704,27 +5725,30 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf, * is not supported yet. * BPF_PROG_TYPE_RAW_TRACEPOINT is fine. */ - return NULL; + return false; } 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; + return false; } ctx_type = find_canonical_prog_ctx_type(prog_type); if (!ctx_type) { bpf_log(log, "btf_vmlinux is malformed\n"); /* should not happen */ - return NULL; + return false; } again: ctx_tname = btf_name_by_offset(btf_vmlinux, ctx_type->name_off); if (!ctx_tname) { /* should not happen */ bpf_log(log, "Please fix kernel include/linux/bpf_types.h\n"); - return NULL; + return false; } + /* program types without named context types work only with arg:ctx tag */ + if (ctx_tname[0] == '\0') + return false; /* 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: @@ -5733,20 +5757,20 @@ again: * { // no fields of skb are ever used } */ if (strcmp(ctx_tname, "__sk_buff") == 0 && strcmp(tname, "sk_buff") == 0) - return ctx_type; + return true; if (strcmp(ctx_tname, "xdp_md") == 0 && strcmp(tname, "xdp_buff") == 0) - return ctx_type; + return true; if (strcmp(ctx_tname, tname)) { /* bpf_user_pt_regs_t is a typedef, so resolve it to * underlying struct and check name again */ if (!btf_type_is_modifier(ctx_type)) - return NULL; + return false; while (btf_type_is_modifier(ctx_type)) ctx_type = btf_type_by_id(btf_vmlinux, ctx_type->type); goto again; } - return ctx_type; + return true; } /* forward declarations for arch-specific underlying types of @@ -5898,7 +5922,7 @@ static int btf_translate_to_vmlinux(struct bpf_verifier_log *log, enum bpf_prog_type prog_type, int arg) { - if (!btf_get_prog_ctx_type(log, btf, t, prog_type, arg)) + if (!btf_is_prog_ctx_type(log, btf, t, prog_type, arg)) return -ENOENT; return find_kern_ctx_type_id(prog_type); } @@ -6130,6 +6154,26 @@ static bool prog_args_trusted(const struct bpf_prog *prog) } } +int btf_ctx_arg_offset(const struct btf *btf, const struct btf_type *func_proto, + u32 arg_no) +{ + const struct btf_param *args; + const struct btf_type *t; + int off = 0, i; + u32 sz; + + args = btf_params(func_proto); + for (i = 0; i < arg_no; i++) { + t = btf_type_by_id(btf, args[i].type); + t = btf_resolve_size(btf, t, &sz); + if (IS_ERR(t)) + return PTR_ERR(t); + off += roundup(sz, 8); + } + + return off; +} + bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) @@ -6266,7 +6310,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, } info->reg_type = ctx_arg_info->reg_type; - info->btf = btf_vmlinux; + info->btf = ctx_arg_info->btf ? : btf_vmlinux; info->btf_id = ctx_arg_info->btf_id; return true; } @@ -6985,9 +7029,78 @@ static bool btf_is_dynptr_ptr(const struct btf *btf, const struct btf_type *t) return false; } +struct bpf_cand_cache { + const char *name; + u32 name_len; + u16 kind; + u16 cnt; + struct { + const struct btf *btf; + u32 id; + } cands[]; +}; + +static DEFINE_MUTEX(cand_cache_mutex); + +static struct bpf_cand_cache * +bpf_core_find_cands(struct bpf_core_ctx *ctx, u32 local_type_id); + +static int btf_get_ptr_to_btf_id(struct bpf_verifier_log *log, int arg_idx, + const struct btf *btf, const struct btf_type *t) +{ + struct bpf_cand_cache *cc; + struct bpf_core_ctx ctx = { + .btf = btf, + .log = log, + }; + u32 kern_type_id, type_id; + int err = 0; + + /* skip PTR and modifiers */ + type_id = t->type; + t = btf_type_by_id(btf, t->type); + while (btf_type_is_modifier(t)) { + type_id = t->type; + t = btf_type_by_id(btf, t->type); + } + + mutex_lock(&cand_cache_mutex); + cc = bpf_core_find_cands(&ctx, type_id); + if (IS_ERR(cc)) { + err = PTR_ERR(cc); + bpf_log(log, "arg#%d reference type('%s %s') candidate matching error: %d\n", + arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off), + err); + goto cand_cache_unlock; + } + if (cc->cnt != 1) { + bpf_log(log, "arg#%d reference type('%s %s') %s\n", + arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off), + cc->cnt == 0 ? "has no matches" : "is ambiguous"); + err = cc->cnt == 0 ? -ENOENT : -ESRCH; + goto cand_cache_unlock; + } + if (btf_is_module(cc->cands[0].btf)) { + bpf_log(log, "arg#%d reference type('%s %s') points to kernel module type (unsupported)\n", + arg_idx, btf_type_str(t), __btf_name_by_offset(btf, t->name_off)); + err = -EOPNOTSUPP; + goto cand_cache_unlock; + } + kern_type_id = cc->cands[0].id; + +cand_cache_unlock: + mutex_unlock(&cand_cache_mutex); + if (err) + return err; + + return kern_type_id; +} + enum btf_arg_tag { ARG_TAG_CTX = 0x1, ARG_TAG_NONNULL = 0x2, + ARG_TAG_TRUSTED = 0x4, + ARG_TAG_NULLABLE = 0x8, }; /* Process BTF of a function to produce high-level expectation of function @@ -7053,6 +7166,8 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) args = (const struct btf_param *)(t + 1); nargs = btf_type_vlen(t); if (nargs > MAX_BPF_FUNC_REG_ARGS) { + if (!is_global) + return -EINVAL; bpf_log(log, "Global function %s() with %d > %d args. Buggy compiler.\n", tname, nargs, MAX_BPF_FUNC_REG_ARGS); return -EINVAL; @@ -7062,6 +7177,8 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); if (!btf_type_is_int(t) && !btf_is_any_enum(t)) { + if (!is_global) + return -EINVAL; bpf_log(log, "Global function %s() doesn't return scalar. Only those are supported.\n", tname); @@ -7089,8 +7206,12 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) if (strcmp(tag, "ctx") == 0) { tags |= ARG_TAG_CTX; + } else if (strcmp(tag, "trusted") == 0) { + tags |= ARG_TAG_TRUSTED; } else if (strcmp(tag, "nonnull") == 0) { tags |= ARG_TAG_NONNULL; + } else if (strcmp(tag, "nullable") == 0) { + tags |= ARG_TAG_NULLABLE; } else { bpf_log(log, "arg#%d has unsupported set of tags\n", i); return -EOPNOTSUPP; @@ -7107,11 +7228,15 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) if (!btf_type_is_ptr(t)) goto skip_pointer; - if ((tags & ARG_TAG_CTX) || btf_get_prog_ctx_type(log, btf, t, prog_type, i)) { + if ((tags & ARG_TAG_CTX) || btf_is_prog_ctx_type(log, btf, t, prog_type, i)) { if (tags & ~ARG_TAG_CTX) { bpf_log(log, "arg#%d has invalid combination of tags\n", i); return -EINVAL; } + if ((tags & ARG_TAG_CTX) && + btf_validate_prog_ctx_type(log, btf, t, i, prog_type, + prog->expected_attach_type)) + return -EINVAL; sub->args[i].arg_type = ARG_PTR_TO_CTX; continue; } @@ -7123,9 +7248,32 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog) sub->args[i].arg_type = ARG_PTR_TO_DYNPTR | MEM_RDONLY; continue; } + if (tags & ARG_TAG_TRUSTED) { + int kern_type_id; + + if (tags & ARG_TAG_NONNULL) { + bpf_log(log, "arg#%d has invalid combination of tags\n", i); + return -EINVAL; + } + + kern_type_id = btf_get_ptr_to_btf_id(log, i, btf, t); + if (kern_type_id < 0) + return kern_type_id; + + sub->args[i].arg_type = ARG_PTR_TO_BTF_ID | PTR_TRUSTED; + if (tags & ARG_TAG_NULLABLE) + sub->args[i].arg_type |= PTR_MAYBE_NULL; + sub->args[i].btf_id = kern_type_id; + continue; + } if (is_global) { /* generic user data pointer */ u32 mem_size; + if (tags & ARG_TAG_NULLABLE) { + bpf_log(log, "arg#%d has invalid combination of tags\n", i); + return -EINVAL; + } + t = btf_type_skip_modifiers(btf, t->type, NULL); ref_t = btf_resolve_size(btf, t, &mem_size); if (IS_ERR(ref_t)) { @@ -7151,28 +7299,13 @@ skip_pointer: sub->args[i].arg_type = ARG_ANYTHING; continue; } + if (!is_global) + return -EINVAL; bpf_log(log, "Arg#%d type %s in %s() is not supported yet.\n", i, btf_type_str(t), tname); return -EINVAL; } - for (i = 0; i < nargs; i++) { - const char *tag; - - if (sub->args[i].arg_type != ARG_PTR_TO_CTX) - continue; - - /* check if arg has "arg:ctx" tag */ - t = btf_type_by_id(btf, args[i].type); - tag = btf_find_decl_tag_value(btf, fn_t, i, "arg:"); - if (IS_ERR_OR_NULL(tag) || strcmp(tag, "ctx") != 0) - continue; - - if (btf_validate_prog_ctx_type(log, btf, t, i, prog_type, - prog->expected_attach_type)) - return -EINVAL; - } - sub->arg_cnt = nargs; sub->args_cached = true; @@ -7649,6 +7782,17 @@ static struct btf *btf_get_module_btf(const struct module *module) return btf; } +static int check_btf_kconfigs(const struct module *module, const char *feature) +{ + if (!module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { + pr_err("missing vmlinux BTF, cannot register %s\n", feature); + return -ENOENT; + } + if (module && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) + pr_warn("missing module BTF, cannot register %s\n", feature); + return 0; +} + BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags) { struct btf *btf = NULL; @@ -8009,15 +8153,8 @@ static int __register_btf_kfunc_id_set(enum btf_kfunc_hook hook, int ret, i; btf = btf_get_module_btf(kset->owner); - if (!btf) { - if (!kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { - pr_err("missing vmlinux BTF, cannot register kfuncs\n"); - return -ENOENT; - } - if (kset->owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) - pr_warn("missing module BTF, cannot register kfuncs\n"); - return 0; - } + if (!btf) + return check_btf_kconfigs(kset->owner, "kfunc"); if (IS_ERR(btf)) return PTR_ERR(btf); @@ -8041,6 +8178,14 @@ int register_btf_kfunc_id_set(enum bpf_prog_type prog_type, { enum btf_kfunc_hook hook; + /* All kfuncs need to be tagged as such in BTF. + * WARN() for initcall registrations that do not check errors. + */ + if (!(kset->set->flags & BTF_SET8_KFUNCS)) { + WARN_ON(!kset->owner); + return -EINVAL; + } + hook = bpf_prog_type_to_kfunc_hook(prog_type); return __register_btf_kfunc_id_set(hook, kset); } @@ -8117,17 +8262,8 @@ int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_c int ret; btf = btf_get_module_btf(owner); - if (!btf) { - if (!owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) { - pr_err("missing vmlinux BTF, cannot register dtor kfuncs\n"); - return -ENOENT; - } - if (owner && IS_ENABLED(CONFIG_DEBUG_INFO_BTF_MODULES)) { - pr_err("missing module BTF, cannot register dtor kfuncs\n"); - return -ENOENT; - } - return 0; - } + if (!btf) + return check_btf_kconfigs(owner, "dtor kfuncs"); if (IS_ERR(btf)) return PTR_ERR(btf); @@ -8242,17 +8378,6 @@ size_t bpf_core_essential_name_len(const char *name) return n; } -struct bpf_cand_cache { - const char *name; - u32 name_len; - u16 kind; - u16 cnt; - struct { - const struct btf *btf; - u32 id; - } cands[]; -}; - static void bpf_free_cands(struct bpf_cand_cache *cands) { if (!cands->cnt) @@ -8273,8 +8398,6 @@ static struct bpf_cand_cache *vmlinux_cand_cache[VMLINUX_CAND_CACHE_SIZE]; #define MODULE_CAND_CACHE_SIZE 31 static struct bpf_cand_cache *module_cand_cache[MODULE_CAND_CACHE_SIZE]; -static DEFINE_MUTEX(cand_cache_mutex); - static void __print_cand_cache(struct bpf_verifier_log *log, struct bpf_cand_cache **cache, int cache_size) @@ -8803,7 +8926,9 @@ int __register_bpf_struct_ops(struct bpf_struct_ops *st_ops) btf = btf_get_module_btf(st_ops->owner); if (!btf) - return -EINVAL; + return check_btf_kconfigs(st_ops->owner, "struct_ops"); + if (IS_ERR(btf)) + return PTR_ERR(btf); log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN); if (!log) { @@ -8823,3 +8948,21 @@ errout: } EXPORT_SYMBOL_GPL(__register_bpf_struct_ops); #endif + +bool btf_param_match_suffix(const struct btf *btf, + const struct btf_param *arg, + const char *suffix) +{ + int suffix_len = strlen(suffix), len; + const char *param_name; + + /* In the future, this can be ported to use BTF tagging */ + param_name = btf_name_by_offset(btf, arg->name_off); + if (str_is_empty(param_name)) + return false; + len = strlen(param_name); + if (len <= suffix_len) + return false; + param_name += len - suffix_len; + return !strncmp(param_name, suffix, suffix_len); +} |