diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2019-12-16 17:49:00 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-12-16 19:59:29 +0100 |
| commit | a2ea07465c8d7984cc6b8b1f0b3324f9b138094a (patch) | |
| tree | ffc04818616b047ecbd2b64f1ae3d9c33108a727 /kernel | |
| parent | bpf: Clear skb->tstamp in bpf_redirect when necessary (diff) | |
| download | linux-a2ea07465c8d7984cc6b8b1f0b3324f9b138094a.tar.xz linux-a2ea07465c8d7984cc6b8b1f0b3324f9b138094a.zip | |
bpf: Fix missing prog untrack in release_maps
Commit da765a2f5993 ("bpf: Add poke dependency tracking for prog array
maps") wrongly assumed that in case of prog load errors, we're cleaning
up all program tracking via bpf_free_used_maps().
However, it can happen that we're still at the point where we didn't copy
map pointers into the prog's aux section such that env->prog->aux->used_maps
is still zero, running into a UAF. In such case, the verifier has similar
release_maps() helper that drops references to used maps from its env.
Consolidate the release code into __bpf_free_used_maps() and call it from
all sides to fix it.
Fixes: da765a2f5993 ("bpf: Add poke dependency tracking for prog array maps")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/1c2909484ca524ae9f55109b06f22b6213e76376.1576514756.git.daniel@iogearbox.net
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/core.c | 14 | ||||
| -rw-r--r-- | kernel/bpf/verifier.c | 14 |
2 files changed, 12 insertions, 16 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 49e32acad7d8..6231858df723 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -2048,18 +2048,24 @@ static void bpf_free_cgroup_storage(struct bpf_prog_aux *aux) } } -static void bpf_free_used_maps(struct bpf_prog_aux *aux) +void __bpf_free_used_maps(struct bpf_prog_aux *aux, + struct bpf_map **used_maps, u32 len) { struct bpf_map *map; - int i; + u32 i; bpf_free_cgroup_storage(aux); - for (i = 0; i < aux->used_map_cnt; i++) { - map = aux->used_maps[i]; + for (i = 0; i < len; i++) { + map = used_maps[i]; if (map->ops->map_poke_untrack) map->ops->map_poke_untrack(map, aux); bpf_map_put(map); } +} + +static void bpf_free_used_maps(struct bpf_prog_aux *aux) +{ + __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); kfree(aux->used_maps); } diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 034ef81f935b..a1acdce77070 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8298,18 +8298,8 @@ next_insn: /* drop refcnt of maps used by the rejected program */ static void release_maps(struct bpf_verifier_env *env) { - enum bpf_cgroup_storage_type stype; - int i; - - for_each_cgroup_storage_type(stype) { - if (!env->prog->aux->cgroup_storage[stype]) - continue; - bpf_cgroup_storage_release(env->prog, - env->prog->aux->cgroup_storage[stype]); - } - - for (i = 0; i < env->used_map_cnt; i++) - bpf_map_put(env->used_maps[i]); + __bpf_free_used_maps(env->prog->aux, env->used_maps, + env->used_map_cnt); } /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */ |