[3.16.y-ckt stable] Patch "ipv4: Fix ip_queue_xmit to pass sk into ip_local_out_sk" has been added to staging queue

[Luis Henriques]

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

    ipv4: Fix ip_queue_xmit to pass sk into ip_local_out_sk

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt21.

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

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From c32cf913bc388e0ab7c5e8174bcedf2090000268 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm at xmission.com>
Date: Wed, 7 Oct 2015 16:48:33 -0500
Subject: ipv4: Fix ip_queue_xmit to pass sk into ip_local_out_sk

commit 850dcc4d4dd7d5da5c1b2a780c5e649c3b649545 upstream.

After a packet has been encapsulated by a tunnel we should use the
tunnel sockets local multicast loopback flag to control if the
encapsulated packet should be locally loopback back.

Pass sk into ip_local_out_sk so that in the rare case we are dealing
with a tunneled packet whose tunnel destination address is a multicast
address the kernel properly decides to loopback this packet.

In practice I don't think this matters as ip_queue_xmit is used by
tcp, l2tp and sctp none of which I am aware of uses ip level
multicasting as they are all point to point communications protocols.
Let's fix this before someone uses ip_queue_xmit for a tunnel protocol
that does use multicast.

Fixes: aad88724c9d5 ("ipv4: add a sock pointer to dst->output() path.")
Fixes: b0270e91014d ("ipv4: add a sock pointer to ip_queue_xmit()")
Signed-off-by: "Eric W. Biederman" <ebiederm at xmission.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv4/ip_output.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index fead914b09f6..d91fda8257bc 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -436,7 +436,7 @@ packet_routed:
 	skb->priority = sk->sk_priority;
 	skb->mark = sk->sk_mark;

-	res = ip_local_out(skb);
+	res = ip_local_out_sk(sk, skb);
 	rcu_read_unlock();
 	return res;