diff options
| -rw-r--r-- | include/linux/bpf.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/bpf.h | 6 | ||||
| -rw-r--r-- | kernel/bpf/syscall.c | 31 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 6 | ||||
| -rw-r--r-- | tools/include/uapi/linux/bpf.h | 6 |
5 files changed, 46 insertions, 4 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index d75902074bd1..c6a6ee1b2938 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -329,6 +329,7 @@ struct bpf_map { atomic64_t sleepable_refcnt; s64 __percpu *elem_count; u64 cookie; /* write-once */ + char *excl_prog_sha; }; static inline const char *btf_field_type_name(enum btf_field_type type) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 233de8677382..57687b2e1c47 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1522,6 +1522,12 @@ union bpf_attr { * If provided, map_flags should have BPF_F_TOKEN_FD flag set. */ __s32 map_token_fd; + + /* Hash of the program that has exclusive access to the map. + */ + __aligned_u64 excl_prog_hash; + /* Size of the passed excl_prog_hash. */ + __u32 excl_prog_hash_size; }; struct { /* anonymous struct used by BPF_MAP_*_ELEM and BPF_MAP_FREEZE commands */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 3f178a0f8eb1..c8ef91acfe98 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -860,6 +860,7 @@ static void bpf_map_free(struct bpf_map *map) * the free of values or special fields allocated from bpf memory * allocator. */ + kfree(map->excl_prog_sha); migrate_disable(); map->ops->map_free(map); migrate_enable(); @@ -1338,9 +1339,9 @@ static bool bpf_net_capable(void) return capable(CAP_NET_ADMIN) || capable(CAP_SYS_ADMIN); } -#define BPF_MAP_CREATE_LAST_FIELD map_token_fd +#define BPF_MAP_CREATE_LAST_FIELD excl_prog_hash_size /* called via syscall */ -static int map_create(union bpf_attr *attr, bool kernel) +static int map_create(union bpf_attr *attr, bpfptr_t uattr) { const struct bpf_map_ops *ops; struct bpf_token *token = NULL; @@ -1534,7 +1535,29 @@ static int map_create(union bpf_attr *attr, bool kernel) attr->btf_vmlinux_value_type_id; } - err = security_bpf_map_create(map, attr, token, kernel); + if (attr->excl_prog_hash) { + bpfptr_t uprog_hash = make_bpfptr(attr->excl_prog_hash, uattr.is_kernel); + + if (attr->excl_prog_hash_size != SHA256_DIGEST_SIZE) { + err = -EINVAL; + goto free_map; + } + + map->excl_prog_sha = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); + if (!map->excl_prog_sha) { + err = -ENOMEM; + goto free_map; + } + + if (copy_from_bpfptr(map->excl_prog_sha, uprog_hash, SHA256_DIGEST_SIZE)) { + err = -EFAULT; + goto free_map; + } + } else if (attr->excl_prog_hash_size) { + return -EINVAL; + } + + err = security_bpf_map_create(map, attr, token, uattr.is_kernel); if (err) goto free_map_sec; @@ -6008,7 +6031,7 @@ static int __sys_bpf(enum bpf_cmd cmd, bpfptr_t uattr, unsigned int size) switch (cmd) { case BPF_MAP_CREATE: - err = map_create(&attr, uattr.is_kernel); + err = map_create(&attr, uattr); break; case BPF_MAP_LOOKUP_ELEM: err = map_lookup_elem(&attr); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6625570ac23d..aef6b266f08d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -20407,6 +20407,12 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, { enum bpf_prog_type prog_type = resolve_prog_type(prog); + if (map->excl_prog_sha && + memcmp(map->excl_prog_sha, prog->digest, SHA256_DIGEST_SIZE)) { + verbose(env, "program's hash doesn't match map's excl_prog_hash\n"); + return -EACCES; + } + if (btf_record_has_field(map->record, BPF_LIST_HEAD) || btf_record_has_field(map->record, BPF_RB_ROOT)) { if (is_tracing_prog_type(prog_type)) { diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 233de8677382..57687b2e1c47 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -1522,6 +1522,12 @@ union bpf_attr { * If provided, map_flags should have BPF_F_TOKEN_FD flag set. */ __s32 map_token_fd; + + /* Hash of the program that has exclusive access to the map. + */ + __aligned_u64 excl_prog_hash; + /* Size of the passed excl_prog_hash. */ + __u32 excl_prog_hash_size; }; struct { /* anonymous struct used by BPF_MAP_*_ELEM and BPF_MAP_FREEZE commands */ |