l2tp: ensure sk->dst is still valid (Closes: #652503)

svn path=/dists/sid/linux-2.6/; revision=18437

debian/changelog

@@ -9,6 +9,7 @@ linux-2.6 (3.1.6-2) UNRELEASED; urgency=low
     - bridge: provide a mtu() method for fake_dst_ops
     - net: introduce DST_NOPEER dst flag
   * rtc: Fix alarm rollover when day or month is out-of-range (Closes: #646429)
+  * l2tp: ensure sk->dst is still valid (Closes: #652503)
 
   [ Jonathan Nieder ]
   * prerm: Print an error message when aborting removal of the running

debian/patches/bugfix/all/l2tp-ensure-sk-dst-is-still-valid.patch

@@ -0,0 +1,38 @@
+From: Florian Westphal <fw@strlen.de>
+Date: Fri, 25 Nov 2011 06:47:16 +0000
+Subject: [PATCH] l2tp: ensure sk->dst is still valid
+
+commit 71b1391a41289735676be02e35239e5aa9fe6ba6 upstream.
+
+When using l2tp over ipsec, the tunnel will hang when rekeying
+occurs. Reason is that the transformer bundle attached to the dst entry
+is now in STATE_DEAD and thus xfrm_output_one() drops all packets
+(XfrmOutStateExpired increases).
+
+Fix this by calling __sk_dst_check (which drops the stale dst
+if xfrm dst->check callback finds that the bundle is no longer valid).
+
+Cc: James Chapman <jchapman@katalix.com>
+Signed-off-by: Florian Westphal <fw@strlen.de>
+Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/l2tp/l2tp_core.c |    2 +-
+ 1 files changed, 1 insertions(+), 1 deletions(-)
+
+diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
+index cf0f308..89ff8c6 100644
+--- a/net/l2tp/l2tp_core.c
++++ b/net/l2tp/l2tp_core.c
+@@ -1072,7 +1072,7 @@ int l2tp_xmit_skb(struct l2tp_session *session, struct sk_buff *skb, int hdr_len
+ 
+ 	/* Get routing info from the tunnel socket */
+ 	skb_dst_drop(skb);
+-	skb_dst_set(skb, dst_clone(__sk_dst_get(sk)));
++	skb_dst_set(skb, dst_clone(__sk_dst_check(sk, 0)));
+ 
+ 	inet = inet_sk(sk);
+ 	fl = &inet->cork.fl;
+-- 
+1.7.7.3
+

debian/patches/series/base

@@ -92,3 +92,4 @@
 + bugfix/all/bridge-provide-a-mtu-method-for-fake_dst_ops.patch
 + bugfix/all/net-introduce-DST_NOPEER-dst-flag.patch
 + bugfix/all/rtc-Fix-alarm-rollover-when-day-or-month-is-out-of-r.patch
++ bugfix/all/l2tp-ensure-sk-dst-is-still-valid.patch