[34-longterm 083/196] can: add missing socket check in can/raw release

[Paul Gortmaker]

From: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 10022a6c66e199d8f61d9044543f38785713cbbd upstream.

v2: added space after 'if' according code style.

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

Thanks to Dave Jones pointing at this issue in net/can/bcm.c

Signed-off-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 net/can/raw.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/can/raw.c b/net/can/raw.c
index da99cf1..9dd45ea 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -281,7 +281,12 @@ static int raw_init(struct sock *sk)
 static int raw_release(struct socket *sock)
 {
 	struct sock *sk = sock->sk;
-	struct raw_sock *ro = raw_sk(sk);
+	struct raw_sock *ro;
+
+	if (!sk)
+		return 0;
+
+	ro = raw_sk(sk);
 
 	unregister_netdevice_notifier(&ro->notifier);
 
-- 
1.7.9.3

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