From: Daniel Borkmann Date: Tue, 17 Dec 2019 12:28:16 +0000 (+0100) Subject: bpf: Fix cgroup local storage prog tracking X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=e47304232b373362228bf233f17bd12b11c9aafc;p=openwrt%2Fstaging%2Fblogic.git bpf: Fix cgroup local storage prog tracking Recently noticed that we're tracking programs related to local storage maps through their prog pointer. This is a wrong assumption since the prog pointer can still change throughout the verification process, for example, whenever bpf_patch_insn_single() is called. Therefore, the prog pointer that was assigned via bpf_cgroup_storage_assign() is not guaranteed to be the same as we pass in bpf_cgroup_storage_release() and the map would therefore remain in busy state forever. Fix this by using the prog's aux pointer which is stable throughout verification and beyond. Fixes: de9cbbaadba5 ("bpf: introduce cgroup storage maps") Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Cc: Roman Gushchin Cc: Martin KaFai Lau Link: https://lore.kernel.org/bpf/1471c69eca3022218666f909bc927a92388fd09e.1576580332.git.daniel@iogearbox.net --- diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index 169fd25f6bc2..9be71c195d74 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -157,8 +157,8 @@ void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage, struct cgroup *cgroup, enum bpf_attach_type type); void bpf_cgroup_storage_unlink(struct bpf_cgroup_storage *storage); -int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *map); -void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *map); +int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *map); +void bpf_cgroup_storage_release(struct bpf_prog_aux *aux, struct bpf_map *map); int bpf_percpu_cgroup_storage_copy(struct bpf_map *map, void *key, void *value); int bpf_percpu_cgroup_storage_update(struct bpf_map *map, void *key, @@ -360,9 +360,9 @@ static inline int cgroup_bpf_prog_query(const union bpf_attr *attr, static inline void bpf_cgroup_storage_set( struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) {} -static inline int bpf_cgroup_storage_assign(struct bpf_prog *prog, +static inline int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *map) { return 0; } -static inline void bpf_cgroup_storage_release(struct bpf_prog *prog, +static inline void bpf_cgroup_storage_release(struct bpf_prog_aux *aux, struct bpf_map *map) {} static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc( struct bpf_prog *prog, enum bpf_cgroup_storage_type stype) { return NULL; } diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 6231858df723..af6b738cf435 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2043,8 +2043,7 @@ static void bpf_free_cgroup_storage(struct bpf_prog_aux *aux) for_each_cgroup_storage_type(stype) { if (!aux->cgroup_storage[stype]) continue; - bpf_cgroup_storage_release(aux->prog, - aux->cgroup_storage[stype]); + bpf_cgroup_storage_release(aux, aux->cgroup_storage[stype]); } } diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c index 2ba750725cb2..6bf605dd4b94 100644 --- a/kernel/bpf/local_storage.c +++ b/kernel/bpf/local_storage.c @@ -20,7 +20,7 @@ struct bpf_cgroup_storage_map { struct bpf_map map; spinlock_t lock; - struct bpf_prog *prog; + struct bpf_prog_aux *aux; struct rb_root root; struct list_head list; }; @@ -420,7 +420,7 @@ const struct bpf_map_ops cgroup_storage_map_ops = { .map_seq_show_elem = cgroup_storage_seq_show_elem, }; -int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map) +int bpf_cgroup_storage_assign(struct bpf_prog_aux *aux, struct bpf_map *_map) { enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map); struct bpf_cgroup_storage_map *map = map_to_storage(_map); @@ -428,14 +428,14 @@ int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map) spin_lock_bh(&map->lock); - if (map->prog && map->prog != prog) + if (map->aux && map->aux != aux) goto unlock; - if (prog->aux->cgroup_storage[stype] && - prog->aux->cgroup_storage[stype] != _map) + if (aux->cgroup_storage[stype] && + aux->cgroup_storage[stype] != _map) goto unlock; - map->prog = prog; - prog->aux->cgroup_storage[stype] = _map; + map->aux = aux; + aux->cgroup_storage[stype] = _map; ret = 0; unlock: spin_unlock_bh(&map->lock); @@ -443,16 +443,16 @@ unlock: return ret; } -void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *_map) +void bpf_cgroup_storage_release(struct bpf_prog_aux *aux, struct bpf_map *_map) { enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map); struct bpf_cgroup_storage_map *map = map_to_storage(_map); spin_lock_bh(&map->lock); - if (map->prog == prog) { - WARN_ON(prog->aux->cgroup_storage[stype] != _map); - map->prog = NULL; - prog->aux->cgroup_storage[stype] = NULL; + if (map->aux == aux) { + WARN_ON(aux->cgroup_storage[stype] != _map); + map->aux = NULL; + aux->cgroup_storage[stype] = NULL; } spin_unlock_bh(&map->lock); } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index a1acdce77070..6ef71429d997 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8268,7 +8268,7 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env) env->used_maps[env->used_map_cnt++] = map; if (bpf_map_is_cgroup_storage(map) && - bpf_cgroup_storage_assign(env->prog, map)) { + bpf_cgroup_storage_assign(env->prog->aux, map)) { verbose(env, "only one cgroup storage of each type is allowed\n"); fdput(f); return -EBUSY;