diff options
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/arraymap.c | 53 | ||||
| -rw-r--r-- | kernel/bpf/btf.c | 419 | ||||
| -rw-r--r-- | kernel/bpf/cgroup.c | 370 | ||||
| -rw-r--r-- | kernel/bpf/core.c | 14 | ||||
| -rw-r--r-- | kernel/bpf/cpumap.c | 53 | ||||
| -rw-r--r-- | kernel/bpf/disasm.c | 5 | ||||
| -rw-r--r-- | kernel/bpf/hashtab.c | 6 | ||||
| -rw-r--r-- | kernel/bpf/helpers.c | 131 | ||||
| -rw-r--r-- | kernel/bpf/local_storage.c | 6 | ||||
| -rw-r--r-- | kernel/bpf/lpm_trie.c | 3 | ||||
| -rw-r--r-- | kernel/bpf/queue_stack_maps.c | 6 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 164 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 618 |
13 files changed, 1619 insertions, 229 deletions
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index c72e0d8e1e65..584636c9e2eb 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -22,7 +22,7 @@ #include "map_in_map.h" #define ARRAY_CREATE_FLAG_MASK \ - (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) + (BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK) static void bpf_array_free_percpu(struct bpf_array *array) { @@ -63,6 +63,7 @@ int array_map_alloc_check(union bpf_attr *attr) if (attr->max_entries == 0 || attr->key_size != 4 || attr->value_size == 0 || attr->map_flags & ~ARRAY_CREATE_FLAG_MASK || + !bpf_map_flags_access_ok(attr->map_flags) || (percpu && numa_node != NUMA_NO_NODE)) return -EINVAL; @@ -160,6 +161,36 @@ static void *array_map_lookup_elem(struct bpf_map *map, void *key) return array->value + array->elem_size * (index & array->index_mask); } +static int array_map_direct_value_addr(const struct bpf_map *map, u64 *imm, + u32 off) +{ + struct bpf_array *array = container_of(map, struct bpf_array, map); + + if (map->max_entries != 1) + return -ENOTSUPP; + if (off >= map->value_size) + return -EINVAL; + + *imm = (unsigned long)array->value; + return 0; +} + +static int array_map_direct_value_meta(const struct bpf_map *map, u64 imm, + u32 *off) +{ + struct bpf_array *array = container_of(map, struct bpf_array, map); + u64 base = (unsigned long)array->value; + u64 range = array->elem_size; + + if (map->max_entries != 1) + return -ENOTSUPP; + if (imm < base || imm >= base + range) + return -ENOENT; + + *off = imm - base; + return 0; +} + /* emit BPF instructions equivalent to C code of array_map_lookup_elem() */ static u32 array_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) { @@ -360,7 +391,8 @@ static void array_map_seq_show_elem(struct bpf_map *map, void *key, return; } - seq_printf(m, "%u: ", *(u32 *)key); + if (map->btf_key_type_id) + seq_printf(m, "%u: ", *(u32 *)key); btf_type_seq_show(map->btf, map->btf_value_type_id, value, m); seq_puts(m, "\n"); @@ -397,6 +429,18 @@ static int array_map_check_btf(const struct bpf_map *map, { u32 int_data; + /* One exception for keyless BTF: .bss/.data/.rodata map */ + if (btf_type_is_void(key_type)) { + if (map->map_type != BPF_MAP_TYPE_ARRAY || + map->max_entries != 1) + return -EINVAL; + + if (BTF_INFO_KIND(value_type->info) != BTF_KIND_DATASEC) + return -EINVAL; + + return 0; + } + if (BTF_INFO_KIND(key_type->info) != BTF_KIND_INT) return -EINVAL; @@ -419,6 +463,8 @@ const struct bpf_map_ops array_map_ops = { .map_update_elem = array_map_update_elem, .map_delete_elem = array_map_delete_elem, .map_gen_lookup = array_map_gen_lookup, + .map_direct_value_addr = array_map_direct_value_addr, + .map_direct_value_meta = array_map_direct_value_meta, .map_seq_show_elem = array_map_seq_show_elem, .map_check_btf = array_map_check_btf, }; @@ -440,6 +486,9 @@ static int fd_array_map_alloc_check(union bpf_attr *attr) /* only file descriptors can be stored in this type of map */ if (attr->value_size != sizeof(u32)) return -EINVAL; + /* Program read-only/write-only not supported for special maps yet. */ + if (attr->map_flags & (BPF_F_RDONLY_PROG | BPF_F_WRONLY_PROG)) + return -EINVAL; return array_map_alloc_check(attr); } diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index bd3921b1514b..cad09858a5f2 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -185,6 +185,16 @@ 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++) + static DEFINE_IDR(btf_idr); static DEFINE_SPINLOCK(btf_idr_lock); @@ -262,6 +272,8 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_RESTRICT] = "RESTRICT", [BTF_KIND_FUNC] = "FUNC", [BTF_KIND_FUNC_PROTO] = "FUNC_PROTO", + [BTF_KIND_VAR] = "VAR", + [BTF_KIND_DATASEC] = "DATASEC", }; struct btf_kind_operations { @@ -314,7 +326,7 @@ static bool btf_type_is_modifier(const struct btf_type *t) return false; } -static bool btf_type_is_void(const struct btf_type *t) +bool btf_type_is_void(const struct btf_type *t) { return t == &btf_void; } @@ -375,13 +387,36 @@ static bool btf_type_is_int(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_INT; } +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; +} + +/* 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 @@ -390,9 +425,11 @@ static bool btf_type_is_int(const struct btf_type *t) 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_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 */ @@ -403,6 +440,7 @@ static bool btf_type_has_size(const struct btf_type *t) case BTF_KIND_STRUCT: case BTF_KIND_UNION: case BTF_KIND_ENUM: + case BTF_KIND_DATASEC: return true; } @@ -467,6 +505,16 @@ 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)]; @@ -478,23 +526,31 @@ 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) +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 (!isalpha(*src) && *src != '_') + 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 (!isalnum(*src) && *src != '_') + if (!__btf_name_char_ok(*src, false, dot_ok)) return false; src++; } @@ -502,6 +558,19 @@ static bool btf_name_valid_identifier(const struct btf *btf, u32 offset) 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) @@ -697,6 +766,32 @@ static void btf_verifier_log_member(struct btf_verifier_env *env, __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 (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) { @@ -974,7 +1069,8 @@ const struct btf_type *btf_type_id_size(const struct btf *btf, } else if (btf_type_is_ptr(size_type)) { size = sizeof(void *); } else { - if (WARN_ON_ONCE(!btf_type_is_modifier(size_type))) + if (WARN_ON_ONCE(!btf_type_is_modifier(size_type) && + !btf_type_is_var(size_type))) return NULL; size = btf->resolved_sizes[size_type_id]; @@ -1509,7 +1605,7 @@ static int btf_modifier_resolve(struct btf_verifier_env *env, u32 next_type_size = 0; next_type = btf_type_by_id(btf, next_type_id); - if (!next_type) { + if (!next_type || btf_type_is_resolve_source_only(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } @@ -1542,6 +1638,53 @@ static int btf_modifier_resolve(struct btf_verifier_env *env, 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; + u32 next_type_size; + + 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, &next_type_size)) { + btf_verifier_log_type(env, v->t, "Invalid type_id"); + return -EINVAL; + } + + env_stack_pop_resolved(env, next_type_id, next_type_size); + + return 0; +} + static int btf_ptr_resolve(struct btf_verifier_env *env, const struct resolve_vertex *v) { @@ -1551,7 +1694,7 @@ static int btf_ptr_resolve(struct btf_verifier_env *env, struct btf *btf = env->btf; next_type = btf_type_by_id(btf, next_type_id); - if (!next_type) { + if (!next_type || btf_type_is_resolve_source_only(next_type)) { btf_verifier_log_type(env, v->t, "Invalid type_id"); return -EINVAL; } @@ -1609,6 +1752,15 @@ static void btf_modifier_seq_show(const struct btf *btf, 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) @@ -1776,7 +1928,8 @@ static int btf_array_resolve(struct btf_verifier_env *env, /* 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)) { + if (btf_type_is_resolve_source_only(index_type) || + btf_type_nosize_or_null(index_type)) { btf_verifier_log_type(env, v->t, "Invalid index"); return -EINVAL; } @@ -1795,7 +1948,8 @@ static int btf_array_resolve(struct btf_verifier_env *env, /* 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)) { + if (btf_type_is_resolve_source_only(elem_type) || + btf_type_nosize_or_null(elem_type)) { btf_verifier_log_type(env, v->t, "Invalid elem"); return -EINVAL; @@ -2016,7 +2170,8 @@ static int btf_struct_resolve(struct btf_verifier_env *env, const struct btf_type *member_type = btf_type_by_id(env->btf, member_type_id); - if (btf_type_nosize_or_null(member_type)) { + if (btf_type_is_resolve_source_only(member_type) || + btf_type_nosize_or_null(member_type)) { btf_verifier_log_member(env, v->t, member, "Invalid member"); return -EINVAL; @@ -2411,6 +2566,222 @@ static struct btf_kind_operations func_ops = { .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) { @@ -2542,6 +2913,8 @@ static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { [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, @@ -2622,13 +2995,17 @@ static bool btf_resolve_valid(struct btf_verifier_env *env, if (!env_type_is_resolved(env, type_id)) return false; - if (btf_type_is_struct(t)) + if (btf_type_is_struct(t) || btf_type_is_datasec(t)) return !btf->resolved_ids[type_id] && - !btf->resolved_sizes[type_id]; + !btf->resolved_sizes[type_id]; - if (btf_type_is_modifier(t) || btf_type_is_ptr(t)) { + 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); + return t && + !btf_type_is_modifier(t) && + !btf_type_is_var(t) && + !btf_type_is_datasec(t); } if (btf_type_is_array(t)) { diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c index 4e807973aa80..fcde0f7b2585 100644 --- a/kernel/bpf/cgroup.c +++ b/kernel/bpf/cgroup.c @@ -11,7 +11,10 @@ #include <linux/kernel.h> #include <linux/atomic.h> #include <linux/cgroup.h> +#include <linux/filter.h> #include <linux/slab.h> +#include <linux/sysctl.h> +#include <linux/string.h> #include <linux/bpf.h> #include <linux/bpf-cgroup.h> #include <net/sock.h> @@ -701,7 +704,7 @@ int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor, EXPORT_SYMBOL(__cgroup_bpf_check_dev_permission); static const struct bpf_func_proto * -cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +cgroup_base_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) { switch (func_id) { case BPF_FUNC_map_lookup_elem: @@ -710,6 +713,12 @@ cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_map_update_elem_proto; case BPF_FUNC_map_delete_elem: return &bpf_map_delete_elem_proto; + case BPF_FUNC_map_push_elem: + return &bpf_map_push_elem_proto; + case BPF_FUNC_map_pop_elem: + return &bpf_map_pop_elem_proto; + case BPF_FUNC_map_peek_elem: + return &bpf_map_peek_elem_proto; case BPF_FUNC_get_current_uid_gid: return &bpf_get_current_uid_gid_proto; case BPF_FUNC_get_local_storage: @@ -725,6 +734,12 @@ cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) } } +static const struct bpf_func_proto * +cgroup_dev_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + return cgroup_base_func_proto(func_id, prog); +} + static bool cgroup_dev_is_valid_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, @@ -762,3 +777,356 @@ const struct bpf_verifier_ops cg_dev_verifier_ops = { .get_func_proto = cgroup_dev_func_proto, .is_valid_access = cgroup_dev_is_valid_access, }; + +/** + * __cgroup_bpf_run_filter_sysctl - Run a program on sysctl + * + * @head: sysctl table header + * @table: sysctl table + * @write: sysctl is being read (= 0) or written (= 1) + * @buf: pointer to buffer passed by user space + * @pcount: value-result argument: value is size of buffer pointed to by @buf, + * result is size of @new_buf if program set new value, initial value + * otherwise + * @ppos: value-result argument: value is position at which read from or write + * to sysctl is happening, result is new position if program overrode it, + * initial value otherwise + * @new_buf: pointer to pointer to new buffer that will be allocated if program + * overrides new value provided by user space on sysctl write + * NOTE: it's caller responsibility to free *new_buf if it was set + * @type: type of program to be executed + * + * Program is run when sysctl is being accessed, either read or written, and + * can allow or deny such access. + * + * This function will return %-EPERM if an attached program is found and + * returned value != 1 during execution. In all other cases 0 is returned. + */ +int __cgroup_bpf_run_filter_sysctl(struct ctl_table_header *head, + struct ctl_table *table, int write, + void __user *buf, size_t *pcount, + loff_t *ppos, void **new_buf, + enum bpf_attach_type type) +{ + struct bpf_sysctl_kern ctx = { + .head = head, + .table = table, + .write = write, + .ppos = ppos, + .cur_val = NULL, + .cur_len = PAGE_SIZE, + .new_val = NULL, + .new_len = 0, + .new_updated = 0, + }; + struct cgroup *cgrp; + int ret; + + ctx.cur_val = kmalloc_track_caller(ctx.cur_len, GFP_KERNEL); + if (ctx.cur_val) { + mm_segment_t old_fs; + loff_t pos = 0; + + old_fs = get_fs(); + set_fs(KERNEL_DS); + if (table->proc_handler(table, 0, (void __user *)ctx.cur_val, + &ctx.cur_len, &pos)) { + /* Let BPF program decide how to proceed. */ + ctx.cur_len = 0; + } + set_fs(old_fs); + } else { + /* Let BPF program decide how to proceed. */ + ctx.cur_len = 0; + } + + if (write && buf && *pcount) { + /* BPF program should be able to override new value with a + * buffer bigger than provided by user. + */ + ctx.new_val = kmalloc_track_caller(PAGE_SIZE, GFP_KERNEL); + ctx.new_len = min_t(size_t, PAGE_SIZE, *pcount); + if (!ctx.new_val || + copy_from_user(ctx.new_val, buf, ctx.new_len)) + /* Let BPF program decide how to proceed. */ + ctx.new_len = 0; + } + + rcu_read_lock(); + cgrp = task_dfl_cgroup(current); + ret = BPF_PROG_RUN_ARRAY(cgrp->bpf.effective[type], &ctx, BPF_PROG_RUN); + rcu_read_unlock(); + + kfree(ctx.cur_val); + + if (ret == 1 && ctx.new_updated) { + *new_buf = ctx.new_val; + *pcount = ctx.new_len; + } else { + kfree(ctx.new_val); + } + + return ret == 1 ? 0 : -EPERM; +} +EXPORT_SYMBOL(__cgroup_bpf_run_filter_sysctl); + +static ssize_t sysctl_cpy_dir(const struct ctl_dir *dir, char **bufp, + size_t *lenp) +{ + ssize_t tmp_ret = 0, ret; + + if (dir->header.parent) { + tmp_ret = sysctl_cpy_dir(dir->header.parent, bufp, lenp); + if (tmp_ret < 0) + return tmp_ret; + } + + ret = strscpy(*bufp, dir->header.ctl_table[0].procname, *lenp); + if (ret < 0) + return ret; + *bufp += ret; + *lenp -= ret; + ret += tmp_ret; + + /* Avoid leading slash. */ + if (!ret) + return ret; + + tmp_ret = strscpy(*bufp, "/", *lenp); + if (tmp_ret < 0) + return tmp_ret; + *bufp += tmp_ret; + *lenp -= tmp_ret; + + return ret + tmp_ret; +} + +BPF_CALL_4(bpf_sysctl_get_name, struct bpf_sysctl_kern *, ctx, char *, buf, + size_t, buf_len, u64, flags) +{ + ssize_t tmp_ret = 0, ret; + + if (!buf) + return -EINVAL; + + if (!(flags & BPF_F_SYSCTL_BASE_NAME)) { + if (!ctx->head) + return -EINVAL; + tmp_ret = sysctl_cpy_dir(ctx->head->parent, &buf, &buf_len); + if (tmp_ret < 0) + return tmp_ret; + } + + ret = strscpy(buf, ctx->table->procname, buf_len); + + return ret < 0 ? ret : tmp_ret + ret; +} + +static const struct bpf_func_proto bpf_sysctl_get_name_proto = { + .func = bpf_sysctl_get_name, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, + .arg4_type = ARG_ANYTHING, +}; + +static int copy_sysctl_value(char *dst, size_t dst_len, char *src, + size_t src_len) +{ + if (!dst) + return -EINVAL; + + if (!dst_len) + return -E2BIG; + + if (!src || !src_len) { + memset(dst, 0, dst_len); + return -EINVAL; + } + + memcpy(dst, src, min(dst_len, src_len)); + + if (dst_len > src_len) { + memset(dst + src_len, '\0', dst_len - src_len); + return src_len; + } + + dst[dst_len - 1] = '\0'; + + return -E2BIG; +} + +BPF_CALL_3(bpf_sysctl_get_current_value, struct bpf_sysctl_kern *, ctx, + char *, buf, size_t, buf_len) +{ + return copy_sysctl_value(buf, buf_len, ctx->cur_val, ctx->cur_len); +} + +static const struct bpf_func_proto bpf_sysctl_get_current_value_proto = { + .func = bpf_sysctl_get_current_value, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_UNINIT_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + +BPF_CALL_3(bpf_sysctl_get_new_value, struct bpf_sysctl_kern *, ctx, char *, buf, + size_t, buf_len) +{ + if (!ctx->write) { + if (buf && buf_len) + memset(buf, '\0', buf_len); + return -EINVAL; + } + return copy_sysctl_value(buf, buf_len, ctx->new_val, ctx->new_len); +} + +static const struct bpf_func_proto bpf_sysctl_get_new_value_proto = { + .func = bpf_sysctl_get_new_value, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_UNINIT_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + +BPF_CALL_3(bpf_sysctl_set_new_value, struct bpf_sysctl_kern *, ctx, + const char *, buf, size_t, buf_len) +{ + if (!ctx->write || !ctx->new_val || !ctx->new_len || !buf || !buf_len) + return -EINVAL; + + if (buf_len > PAGE_SIZE - 1) + return -E2BIG; + + memcpy(ctx->new_val, buf, buf_len); + ctx->new_len = buf_len; + ctx->new_updated = 1; + + return 0; +} + +static const struct bpf_func_proto bpf_sysctl_set_new_value_proto = { + .func = bpf_sysctl_set_new_value, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_CTX, + .arg2_type = ARG_PTR_TO_MEM, + .arg3_type = ARG_CONST_SIZE, +}; + +static const struct bpf_func_proto * +sysctl_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + switch (func_id) { + case BPF_FUNC_strtol: + return &bpf_strtol_proto; + case BPF_FUNC_strtoul: + return &bpf_strtoul_proto; + case BPF_FUNC_sysctl_get_name: + return &bpf_sysctl_get_name_proto; + case BPF_FUNC_sysctl_get_current_value: + return &bpf_sysctl_get_current_value_proto; + case BPF_FUNC_sysctl_get_new_value: + return &bpf_sysctl_get_new_value_proto; + case BPF_FUNC_sysctl_set_new_value: + return &bpf_sysctl_set_new_value_proto; + default: + return cgroup_base_func_proto(func_id, prog); + } +} + +static bool sysctl_is_valid_access(int off, int size, enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + const int size_default = sizeof(__u32); + + if (off < 0 || off + size > sizeof(struct bpf_sysctl) || off % size) + return false; + + switch (off) { + case offsetof(struct bpf_sysctl, write): + if (type != BPF_READ) + return false; + bpf_ctx_record_field_size(info, size_default); + return bpf_ctx_narrow_access_ok(off, size, size_default); |