tipc: reinitialize pointer after skb linearize

The msg pointer into header may change after skb linearization.
We must reinitialize it after calling skb_linearize to prevent
operating on a freed or invalid pointer.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reported-by: Tamás Végh <tamas.vegh@ericsson.com>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 562c926..c5ac436 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -539,6 +539,7 @@
 	*err = -TIPC_ERR_NO_NAME;
 	if (skb_linearize(skb))
 		return false;
+	msg = buf_msg(skb);
 	if (msg_reroute_cnt(msg))
 		return false;
 	dnode = addr_domain(net, msg_lookup_scope(msg));