Commit 165511b9 authored Jan 23, 2023 by Hyunwoo Kim Committed by Greg Kroah-Hartman Feb 22, 2023

net/x25: Fix to not accept on connected socket



[ Upstream commit f2b0b5210f67c56a3bcdf92ff665fb285d6e0067 ]

When listen() and accept() are called on an x25 socket
that connect() succeeds, accept() succeeds immediately.
This is because x25_connect() queues the skb to
sk->sk_receive_queue, and x25_accept() dequeues it.

This creates a child socket with the sk of the parent
x25 socket, which can cause confusion.

Fix x25_listen() to return -EINVAL if the socket has
already been successfully connect()ed to avoid this issue.

Signed-off-by: Hyunwoo Kim <v4bel@theori.io>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent b05664e0

net/x25/af_x25.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -492,6 +492,12 @@ static int x25_listen(struct socket *sock, int backlog)
		int rc = -EOPNOTSUPP;

		lock_sock(sk);
		if (sock->state != SS_UNCONNECTED) {
		rc = -EINVAL;
		release_sock(sk);
		return rc;
		}

		if (sk->sk_state != TCP_LISTEN) {
		memset(&x25_sk(sk)->dest_addr, 0, X25_ADDR_LEN);
		sk->sk_max_ack_backlog = backlog;