Commit e21dba7a authored by Martin Schiller's avatar Martin Schiller Committed by David S. Miller
Browse files

net/x25: fix nonblocking connect

This patch fixes 2 issues in x25_connect():

1. It makes absolutely no sense to reset the neighbour and the
connection state after a (successful) nonblocking call of x25_connect.
This prevents any connection from being established, since the response
(call accept) cannot be processed.

2. Any further calls to x25_connect() while a call is pending should
simply return, instead of creating new Call Request (on different
logical channels).

This patch should also fix the "KASAN: null-ptr-deref Write in
x25_connect" and "BUG: unable to handle kernel NULL pointer dereference
in x25_connect" bugs reported by syzbot.
Signed-off-by: default avatarMartin Schiller <>
Signed-off-by: default avatarDavid S. Miller <>
parent 3249b1e4
......@@ -766,6 +766,10 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr,
if (sk->sk_state == TCP_ESTABLISHED)
goto out;
rc = -EALREADY; /* Do nothing if call is already in progress */
if (sk->sk_state == TCP_SYN_SENT)
goto out;
sk->sk_state = TCP_CLOSE;
sock->state = SS_UNCONNECTED;
......@@ -812,7 +816,7 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr,
/* Now the loop */
if (sk->sk_state != TCP_ESTABLISHED && (flags & O_NONBLOCK))
goto out_put_neigh;
goto out;
rc = x25_wait_for_connection_establishment(sk);
if (rc)
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