fib_frontend: fix possible NULL pointer dereference
The two commits 0115e8e30d (net: remove delay at device dismantle) and
748e2d9396a (net: reinstate rtnl in call_netdevice_notifiers()) silently
removed a NULL pointer check for in_dev since Linux 3.7.
This patch re-introduces this check as it causes crashing the kernel when
setting small mtu values on non-ip capable netdevices.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index d846304..c7539e2 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1047,6 +1047,8 @@
}
in_dev = __in_dev_get_rtnl(dev);
+ if (!in_dev)
+ return NOTIFY_DONE;
switch (event) {
case NETDEV_UP: