[3.11.y.z extended stable] Patch "ip6tnl: fix use after free of fb_tnl_dev" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    ip6tnl: fix use after free of fb_tnl_dev

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 980aa462e2768b9f772da0740c176c38738f582c Mon Sep 17 00:00:00 2001
From: Nicolas Dichtel <nicolas.dichtel at 6wind.com>
Date: Fri, 13 Dec 2013 10:06:35 +0100
Subject: ip6tnl: fix use after free of fb_tnl_dev

The upstream commit bb8140947a24 ("ip6tnl: allow to use rtnl ops on fb tunnel")
(backported into linux-3.10.y) left a bug which was fixed upstream by commit
1e9f3d6f1c40 ("ip6tnl: fix use after free of fb_tnl_dev").

The problem is a bit different in linux-3.10.y, because there is no x-netns
support (upstream commit 0bd8762824e7 ("ip6tnl: add x-netns support")).
When ip6_tunnel.ko is unloaded, FB device is deleted by rtnl_link_unregister()
and then we try to delete it again in ip6_tnl_destroy_tunnels().

This patch removes the second deletion.

Reported-by: Steven Rostedt <rostedt at goodmis.org>
Suggested-by: Steven Rostedt <rostedt at goodmis.org>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel at 6wind.com>
Cc: David Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv6/ip6_tunnel.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index cf5d490..85416a0 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1717,8 +1717,6 @@ static void __net_exit ip6_tnl_destroy_tunnels(struct ip6_tnl_net *ip6n)
 		}
 	}

-	t = rtnl_dereference(ip6n->tnls_wc[0]);
-	unregister_netdevice_queue(t->dev, &list);
 	unregister_netdevice_many(&list);
 }

--
1.8.3.2