diff options
| -rw-r--r-- | include/uapi/linux/btf.h | 18 | ||||
| -rw-r--r-- | kernel/bpf/btf.c | 389 |
2 files changed, 354 insertions, 53 deletions
diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index 972265f32871..14f66948fc95 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -40,7 +40,8 @@ struct btf_type { /* "size" is used by INT, ENUM, STRUCT and UNION. * "size" tells the size of the type it is describing. * - * "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT. + * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, + * FUNC and FUNC_PROTO. * "type" is a type_id referring to another type. */ union { @@ -64,8 +65,10 @@ struct btf_type { #define BTF_KIND_VOLATILE 9 /* Volatile */ #define BTF_KIND_CONST 10 /* Const */ #define BTF_KIND_RESTRICT 11 /* Restrict */ -#define BTF_KIND_MAX 11 -#define NR_BTF_KINDS 12 +#define BTF_KIND_FUNC 12 /* Function */ +#define BTF_KIND_FUNC_PROTO 13 /* Function Proto */ +#define BTF_KIND_MAX 13 +#define NR_BTF_KINDS 14 /* For some specific BTF_KIND, "struct btf_type" is immediately * followed by extra data. @@ -110,4 +113,13 @@ struct btf_member { __u32 offset; /* offset in bits */ }; +/* BTF_KIND_FUNC_PROTO is followed by multiple "struct btf_param". + * The exact number of btf_param is stored in the vlen (of the + * info in "struct btf_type"). + */ +struct btf_param { + __u32 name_off; + __u32 type; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 2a50d87de485..6a2be79b73fc 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -5,6 +5,7 @@ #include <uapi/linux/types.h> #include <linux/seq_file.h> #include <linux/compiler.h> +#include <linux/ctype.h> #include <linux/errno.h> #include <linux/slab.h> #include <linux/anon_inodes.h> @@ -259,6 +260,8 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_VOLATILE] = "VOLATILE", [BTF_KIND_CONST] = "CONST", [BTF_KIND_RESTRICT] = "RESTRICT", + [BTF_KIND_FUNC] = "FUNC", + [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", }; struct btf_kind_operations { @@ -281,6 +284,9 @@ struct btf_kind_operations { 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 @@ -314,9 +320,20 @@ static bool btf_type_is_fwd(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_FWD; } +static bool btf_type_is_func(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC; +} + +static bool btf_type_is_func_proto(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_FUNC_PROTO; +} + static bool btf_type_nosize(const struct btf_type *t) { - return btf_type_is_void(t) || btf_type_is_fwd(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) @@ -433,6 +450,30 @@ static bool btf_name_offset_valid(const struct btf *btf, u32 offset) offset < btf->hdr.str_len; } +/* Only C-style identifier is permitted. This can be relaxed if + * necessary. + */ +static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) +{ + /* offset must be valid */ + const char *src = &btf->strings[offset]; + const char *src_limit; + + if (!isalpha(*src) && *src != '_') + return false; + + /* set a limit on identifier length */ + src_limit = src + KSYM_NAME_LEN; + src++; + while (*src && src < src_limit) { + if (!isalnum(*src) && *src != '_') + return false; + src++; + } + + return !*src; +} + static const char *btf_name_by_offset(const struct btf *btf, u32 offset) { if (!offset) @@ -747,11 +788,15 @@ static bool env_type_is_resolve_sink(const struct btf_verifier_env *env, /* int, enum or void is a sink */ return !btf_type_needs_resolve(next_type); case RESOLVE_PTR: - /* int, enum, void, struct or array is a sink for 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 or ptr is a sink for struct and 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); @@ -1170,10 +1215,6 @@ static int btf_modifier_resolve(struct btf_verifier_env *env, return -EINVAL; } - /* "typedef void new_void", "const void"...etc */ - if (btf_type_is_void(next_type) || btf_type_is_fwd(next_type)) - goto resolved; - 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); @@ -1184,13 +1225,18 @@ static int btf_modifier_resolve(struct btf_verifier_env *env, * 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, &next_type_size) && - !btf_type_nosize(btf_type_id_resolve(btf, &next_type_id))) { - btf_verifier_log_type(env, v->t, "Invalid type_id"); - return -EINVAL; + if (!btf_type_id_size(btf, &next_type_id, &next_type_size)) { + 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_verifier_log_type(env, v->t, "Invalid type_id"); + return -EINVAL; + } } -resolved: env_stack_pop_resolved(env, next_type_id, next_type_size); return 0; @@ -1203,7 +1249,6 @@ static int btf_ptr_resolve(struct btf_verifier_env *env, const struct btf_type *t = v->t; u32 next_type_id = t->type; struct btf *btf = env->btf; - u32 next_type_size = 0; next_type = btf_type_by_id(btf, next_type_id); if (!next_type) { @@ -1211,10 +1256,6 @@ static int btf_ptr_resolve(struct btf_verifier_env *env, return -EINVAL; } - /* "void *" */ - if (btf_type_is_void(next_type) || btf_type_is_fwd(next_type)) - goto resolved; - 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); @@ -1241,13 +1282,18 @@ static int btf_ptr_resolve(struct btf_verifier_env *env, resolved_type_id); } - if (!btf_type_id_size(btf, &next_type_id, &next_type_size) && - !btf_type_nosize(btf_type_id_resolve(btf, &next_type_id))) { - btf_verifier_log_type(env, v->t, "Invalid type_id"); - return -EINVAL; + 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; + } } -resolved: env_stack_pop_resolved(env, next_type_id, 0); return 0; @@ -1787,6 +1833,232 @@ static struct btf_kind_operations enum_ops = { .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; + } + + 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, + .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_verifier_log_type(env, t, "vlen != 0"); + 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, + .log_details = btf_ref_type_log, + .seq_show = btf_df_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, @@ -1799,6 +2071,8 @@ static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { [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, }; static s32 btf_check_meta(struct btf_verifier_env *env, @@ -1870,30 +2144,6 @@ static int btf_check_all_metas(struct btf_verifier_env *env) return 0; } -static int btf_resolve(struct btf_verifier_env *env, - const struct btf_type *t, u32 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"); - - return err; -} - static bool btf_resolve_valid(struct btf_verifier_env *env, const struct btf_type *t, u32 type_id) @@ -1927,6 +2177,39 @@ static bool btf_resolve_valid(struct btf_verifier_env *env, 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; @@ -1949,10 +2232,16 @@ static int btf_check_all_types(struct btf_verifier_env *env) return err; } - if (btf_type_needs_resolve(t) && - !btf_resolve_valid(env, t, type_id)) { - btf_verifier_log_type(env, t, "Invalid resolve state"); - return -EINVAL; + 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; } } |