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>
This commit is contained in:
Hyunwoo Kim 2023-01-23 11:43:23 -08:00 committed by Greg Kroah-Hartman
parent b05664e036
commit 165511b99e

View File

@ -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;