From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Thu, 23 Jan 2014 09:19:34 +0000 (+0100)
Subject: fib_frontend: fix possible NULL pointer dereference
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=a0065f266a9b5d51575535a25c15ccbeed9a9966;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

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 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: