From: Krishna Kumar <krkumar2@in.ibm.com>
Date: Thu, 14 Apr 2011 06:07:04 +0000 (+0000)
Subject: ip6_pol_route panic: Do not allow VLAN on loopback
X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=0553c891fabd287726b41076cfd03fe7e5ab596f;p=linux-edison.git

ip6_pol_route panic: Do not allow VLAN on loopback

Several tests in the ipv6 routing code check IFF_LOOPBACK, and
allowing stacking such as VLAN'ing on top of loopback results in a
netdevice which reports IFF_LOOPBACK but really isn't the loopback
device.

Instead of spamming the ipv6 routing code with even more special tests,
simply disallow VLAN over loopback.

The result of this patch is:

# modprobe 8021q
# vconfig add lo 43
ERROR: trying to add VLAN #43 to IF -:lo:-  error: Operation not supported

Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/loopback.c b/drivers/net/loopback.c
index ea0dc451da9..d70fb76edb7 100644
--- a/drivers/net/loopback.c
+++ b/drivers/net/loopback.c
@@ -173,7 +173,8 @@ static void loopback_setup(struct net_device *dev)
 		| NETIF_F_RXCSUM
 		| NETIF_F_HIGHDMA
 		| NETIF_F_LLTX
-		| NETIF_F_NETNS_LOCAL;
+		| NETIF_F_NETNS_LOCAL
+		| NETIF_F_VLAN_CHALLENGED;
 	dev->ethtool_ops	= &loopback_ethtool_ops;
 	dev->header_ops		= &eth_header_ops;
 	dev->netdev_ops		= &loopback_ops;