can: Add missing socket check in can/bcm release.

We can get here with a NULL socket argument passed from userspace,
so we need to handle it accordingly.

Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
index 57b1aed79014..8a6a05e7c3c8 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -1427,9 +1427,14 @@ static int bcm_init(struct sock *sk)
 static int bcm_release(struct socket *sock)
 {
         struct sock *sk = sock->sk;
-        struct bcm_sock *bo = bcm_sk(sk);
+        struct bcm_sock *bo;
         struct bcm_op *op, *next;
 
+        if (sk == NULL)
+                return 0;
+
+        bo = bcm_sk(sk);
+
         /* remove bcm_ops, timer, rx_unregister(), etc. */
 
         unregister_netdevice_notifier(&bo->notifier);