[PATCH 3.11 208/208] ip6tnl: fix use after free of fb_tnl_dev

[Luis Henriques]

3.11.10.2 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>

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@xxxxxxxxxxx>
Suggested-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/