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@xxxxxxxxx>
---
net/x25/af_x25.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/net/x25/af_x25.c b/net/x25/af_x25.c
index 3b55502b2965..4407a625daa6 100644
--- a/net/x25/af_x25.c
+++ b/net/x25/af_x25.c
@@ -482,6 +482,12 @@ static int x25_listen(struct socket *sock, int backlog)
int rc = -EOPNOTSUPP;
lock_sock(sk);
+ if (sock->state == SS_CONNECTED) {
+ 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;
--
2.25.1
