af_unix: Use skb_queue_empty_lockless() in unix_release_sock().

[ Upstream commit 83690b82d2 ]

If the socket type is SOCK_STREAM or SOCK_SEQPACKET, unix_release_sock()
checks the length of the peer socket's recvq under unix_state_lock().

However, unix_stream_read_generic() calls skb_unlink() after releasing
the lock.  Also, for SOCK_SEQPACKET, __skb_try_recv_datagram() unlinks
skb without unix_state_lock().

Thues, unix_state_lock() does not protect qlen.

Let's use skb_queue_empty_lockless() in unix_release_sock().

Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2024-06-04 09:52:39 -07:00 committed by Greg Kroah-Hartman
parent 0142dce077
commit 9402362b4c

View File

@ -555,7 +555,7 @@ static void unix_release_sock(struct sock *sk, int embrion)
unix_state_lock(skpair);
/* No more writes */
WRITE_ONCE(skpair->sk_shutdown, SHUTDOWN_MASK);
if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
if (!skb_queue_empty_lockless(&sk->sk_receive_queue) || embrion)
WRITE_ONCE(skpair->sk_err, ECONNRESET);
unix_state_unlock(skpair);
skpair->sk_state_change(skpair);