Patch "ipv6: icmp6: Allow icmp messages to be looped back" has been added to the 4.9-stable tree

Patch "ipv6: icmp6: Allow icmp messages to be looped back" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ipv6: icmp6: Allow icmp messages to be looped back

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ipv6-icmp6-allow-icmp-messages-to-be-looped-back.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Wed Feb 28 16:13:29 CET 2018
From: Brendan McGrath <redmcg@redmandi.dyndns.org>
Date: Wed, 13 Dec 2017 22:14:57 +1100
Subject: ipv6: icmp6: Allow icmp messages to be looped back

From: Brendan McGrath <redmcg@redmandi.dyndns.org>


[ Upstream commit 588753f1eb18978512b1c9b85fddb457d46f9033 ]

One example of when an ICMPv6 packet is required to be looped back is
when a host acts as both a Multicast Listener and a Multicast Router.

A Multicast Router will listen on address ff02::16 for MLDv2 messages.

Currently, MLDv2 messages originating from a Multicast Listener running
on the same host as the Multicast Router are not being delivered to the
Multicast Router. This is due to dst.input being assigned the default
value of dst_discard.

This results in the packet being looped back but discarded before being
delivered to the Multicast Router.

This patch sets dst.input to ip6_input to ensure a looped back packet
is delivered to the Multicast Router.

Signed-off-by: Brendan McGrath <redmcg@redmandi.dyndns.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv6/route.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1651,6 +1651,7 @@ struct dst_entry *icmp6_dst_alloc(struct
 	}
 
 	rt->dst.flags |= DST_HOST;
+	rt->dst.input = ip6_input;
 	rt->dst.output  = ip6_output;
 	atomic_set(&rt->dst.__refcnt, 1);
 	rt->rt6i_gateway  = fl6->daddr;


Patches currently in stable-queue which might be from redmcg@redmandi.dyndns.org are

queue-4.9/ipv6-icmp6-allow-icmp-messages-to-be-looped-back.patch