[PATCH linux-3.10.y] ip6tnl: fix use after free of fb_tnl_dev

* [PATCH linux-3.10.y] ip6tnl: fix use after free of fb_tnl_dev
       [not found] <20131212.153545.1184197791301496227.davem@davemloft.net>
@ 2013-12-13  9:06 ` Nicolas Dichtel
  2013-12-17 19:40   ` David Miller
  0 siblings, 1 reply; 5+ messages in thread
From: Nicolas Dichtel @ 2013-12-13  9:06 UTC (permalink / raw)
  To: netdev, davem
  Cc: gregkh, rostedt, linux-kernel, stable, williams, linux-rt-users,
	lclaudio, Nicolas Dichtel

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@goodmis.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.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 0516ebbea80b..209bb4d6e188 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1711,8 +1711,6 @@ 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);
 }
 
-- 
1.8.4.1

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