[PATCH 3.19.y-ckt 151/251] NET: ROSE: Don't dereference NULL neighbour pointer.

[Kamal Mostafa <kamal@canonical.com>]

3.19.8-ckt4 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ralf Baechle <ralf@linux-mips.org>

commit d496f7842aada20c61e6044b3395383fa972872c upstream.

A ROSE socket doesn't necessarily always have a neighbour pointer so check
if the neighbour pointer is valid before dereferencing it.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Tested-by: Bernard Pidoux <f6bvp@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 net/rose/af_rose.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c
index 43bac7c..58e759e 100644
--- a/net/rose/af_rose.c
+++ b/net/rose/af_rose.c
@@ -192,7 +192,8 @@ static void rose_kill_by_device(struct net_device *dev)
 
 		if (rose->device == dev) {
 			rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0);
-			rose->neighbour->use--;
+			if (rose->neighbour)
+				rose->neighbour->use--;
 			rose->device = NULL;
 		}
 	}
-- 
1.9.1