[3.13.y-ckt stable] Patch "bridge: fix parsing of MLDv2 reports" has been added to staging queue

[Kamal Mostafa]

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

    bridge: fix parsing of MLDv2 reports

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt22.

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

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From e988a5e0d0f0fdf8d64a04f4604956bc97fceb3b Mon Sep 17 00:00:00 2001
From: Thadeu Lima de Souza Cascardo <cascardo at redhat.com>
Date: Fri, 22 May 2015 12:18:59 -0300
Subject: bridge: fix parsing of MLDv2 reports

commit 47cc84ce0c2fe75c99ea5963c4b5704dd78ead54 upstream.

When more than a multicast address is present in a MLDv2 report, all but
the first address is ignored, because the code breaks out of the loop if
there has not been an error adding that address.

This has caused failures when two guests connected through the bridge
tried to communicate using IPv6. Neighbor discoveries would not be
transmitted to the other guest when both used a link-local address and a
static address.

This only happens when there is a MLDv2 querier in the network.

The fix will only break out of the loop when there is a failure adding a
multicast address.

The mdb before the patch:

dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp

After the patch:

dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::fb temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp
dev ovirtmgmt port bond0.86 grp ff02::d temp
dev ovirtmgmt port vnet0 grp ff02::1:ff00:76 temp
dev ovirtmgmt port bond0.86 grp ff02::16 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff00:77 temp
dev ovirtmgmt port bond0.86 grp ff02::1:ff00:def temp
dev ovirtmgmt port bond0.86 grp ff02::1:ffa1:40bf temp

Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.")
Reported-by: Rik Theys <Rik.Theys at esat.kuleuven.be>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo at redhat.com>
Tested-by: Rik Theys <Rik.Theys at esat.kuleuven.be>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/bridge/br_multicast.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c
index 93067ec..11a2e6c 100644
--- a/net/bridge/br_multicast.c
+++ b/net/bridge/br_multicast.c
@@ -1056,7 +1056,7 @@ static int br_ip6_multicast_mld2_report(struct net_bridge *br,

 		err = br_ip6_multicast_add_group(br, port, &grec->grec_mca,
 						 vid);
-		if (!err)
+		if (err)
 			break;
 	}

--
1.9.1