net/x25: Fix null-ptr-deref in x25_connect

[ Upstream commit 361182308766a265b6c521879b34302617a8c209 ]

This fixes a regression for blocking connects introduced by commit
4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect").

The x25->neighbour is already set to "NULL" by x25_disconnect() now,
while a blocking connect is waiting in
x25_wait_for_connection_establishment(). Therefore x25->neighbour must
not be accessed here again and x25->state is also already set to
X25_STATE_0 by x25_disconnect().

Fixes: 4becb7ee5b3d ("net/x25: Fix x25_neigh refcnt leak when x25 disconnect")
Signed-off-by: Martin Schiller <ms@dev.tdt.de>
Reviewed-by: Xie He <xie.he.0141@gmail.com>
Link: https://lore.kernel.org/r/20201109065449.9014-1-ms@dev.tdt.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Martin Schiller 2020-11-09 07:54:49 +01:00 committed by Greg Kroah-Hartman
parent 7e332a5c0e
commit c59039a088

View File

@ -819,7 +819,7 @@ static int x25_connect(struct socket *sock, struct sockaddr *uaddr,
sock->state = SS_CONNECTED;
rc = 0;
out_put_neigh:
if (rc) {
if (rc && x25->neighbour) {
read_lock_bh(&x25_list_lock);
x25_neigh_put(x25->neighbour);
x25->neighbour = NULL;