Commit 0b2dc839 authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by Daniel Borkmann
Browse files

bpf, sockhash: Synchronize_rcu before free'ing map

We need to have a synchronize_rcu before free'ing the sockhash because any
outstanding psock references will have a pointer to the map and when they
use it, this could trigger a use after free.

This is a sister fix for sockhash, following commit 2bb90e5c ("bpf:
sockmap, synchronize_rcu before free'ing map") which addressed sockmap,
which comes from a manual audit.

Fixes: 604326b4

 ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200206111652.694507-3-jakub@cloudflare.com
parent db6a5018
...@@ -250,6 +250,7 @@ static void sock_map_free(struct bpf_map *map) ...@@ -250,6 +250,7 @@ static void sock_map_free(struct bpf_map *map)
} }
raw_spin_unlock_bh(&stab->lock); raw_spin_unlock_bh(&stab->lock);
/* wait for psock readers accessing its map link */
synchronize_rcu(); synchronize_rcu();
bpf_map_area_free(stab->sks); bpf_map_area_free(stab->sks);
...@@ -877,6 +878,9 @@ static void sock_hash_free(struct bpf_map *map) ...@@ -877,6 +878,9 @@ static void sock_hash_free(struct bpf_map *map)
raw_spin_unlock_bh(&bucket->lock); raw_spin_unlock_bh(&bucket->lock);
} }
/* wait for psock readers accessing its map link */
synchronize_rcu();
bpf_map_area_free(htab->buckets); bpf_map_area_free(htab->buckets);
kfree(htab); kfree(htab);
} }
......
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