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authorJakub Sitnicki <jakub@cloudflare.com>2020-02-06 12:16:51 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2020-02-07 22:36:26 +0100
commit0b2dc83906cf1e694e48003eae5df8fa63f76fd9 (patch)
tree2cb216e87bfd171ea95e8af962f20ed0fa2a3e96 /net
parentdb6a5018b6e008c1d69c6628cdaa9541b8e70940 (diff)
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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 2bb90e5cc90e ("bpf: sockmap, synchronize_rcu before free'ing map") which addressed sockmap, which comes from a manual audit. Fixes: 604326b41a6fb ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200206111652.694507-3-jakub@cloudflare.com
Diffstat (limited to 'net')
-rw-r--r--net/core/sock_map.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 992504478e68..085cef5857bb 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -250,6 +250,7 @@ static void sock_map_free(struct bpf_map *map)
}
raw_spin_unlock_bh(&stab->lock);
+ /* wait for psock readers accessing its map link */
synchronize_rcu();
bpf_map_area_free(stab->sks);
@@ -877,6 +878,9 @@ static void sock_hash_free(struct bpf_map *map)
raw_spin_unlock_bh(&bucket->lock);
}
+ /* wait for psock readers accessing its map link */
+ synchronize_rcu();
+
bpf_map_area_free(htab->buckets);
kfree(htab);
}