diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2019-12-16 17:49:00 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2019-12-16 10:59:29 -0800 |
| commit | a2ea07465c8d7984cc6b8b1f0b3324f9b138094a (patch) | |
| tree | ffc04818616b047ecbd2b64f1ae3d9c33108a727 /kernel/bpf/core.c | |
| parent | 5133498f4ad1123a5ffd4c08df6431dab882cc32 (diff) | |
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/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 14 |
1 files changed, 10 insertions, 4 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); } |