From a0065f266a9b5d51575535a25c15ccbeed9a9966 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Thu, 23 Jan 2014 10:19:34 +0100
Subject: [PATCH] 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>
---
net/ipv4/fib_frontend.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index d846304b7b89..c7539e22868b 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1047,6 +1047,8 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo
}
in_dev = __in_dev_get_rtnl(dev);
+ if (!in_dev)
+ return NOTIFY_DONE;
switch (event) {
case NETDEV_UP:
--
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