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| author | Daniel Borkmann <daniel@iogearbox.net> | 2018-08-16 21:49:09 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-15 09:46:48 +0200 |
| commit | 98d30c6ae96a5dd66f638d1fccb26779bd655b47 (patch) | |
| tree | 862888ef1e586677a0a7329540d8fbe56bea0faa /kernel | |
| parent | af160422460ea8e5824e6930566f4c8ae91f3066 (diff) | |
| download | linux-stable-98d30c6ae96a5dd66f638d1fccb26779bd655b47.tar.gz linux-stable-98d30c6ae96a5dd66f638d1fccb26779bd655b47.tar.bz2 linux-stable-98d30c6ae96a5dd66f638d1fccb26779bd655b47.zip | |
bpf, sockmap: fix map elem deletion race with smap_stop_sock
[ Upstream commit 166ab6f0a0702fdd4d865ad5090bf3094ed83428 ]
The smap_start_sock() and smap_stop_sock() are each protected under
the sock->sk_callback_lock from their call-sites except in the case
of sock_map_delete_elem() where we drop the old socket from the map
slot. This is racy because the same sock could be part of multiple
sock maps, so we run smap_stop_sock() in parallel, and given at that
point psock->strp_enabled might be true on both CPUs, we might for
example wrongly restore the sk->sk_data_ready / sk->sk_write_space.
Therefore, hold the sock->sk_callback_lock as well on delete. Looks
like 2f857d04601a ("bpf: sockmap, remove STRPARSER map_flags and add
multi-map support") had this right, but later on e9db4ef6bf4c ("bpf:
sockhash fix omitted bucket lock in sock_close") removed it again
from delete leaving this smap_stop_sock() instance unprotected.
Fixes: e9db4ef6bf4c ("bpf: sockhash fix omitted bucket lock in sock_close")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/sockmap.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index c4d75c52b4fc..694da74d7df0 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -1784,8 +1784,11 @@ static int sock_map_delete_elem(struct bpf_map *map, void *key) if (!psock) goto out; - if (psock->bpf_parse) + if (psock->bpf_parse) { + write_lock_bh(&sock->sk_callback_lock); smap_stop_sock(psock, sock); + write_unlock_bh(&sock->sk_callback_lock); + } smap_list_map_remove(psock, &stab->sock_map[k]); smap_release_sock(psock, sock); out: |