Patch "vxlan: fix test which detect duplicate vxlan iface" has been added to the 4.1-stable tree

[<gregkh@linuxfoundation.org>]

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

    vxlan: fix test which detect duplicate vxlan iface

to the 4.1-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:
     vxlan-fix-test-which-detect-duplicate-vxlan-iface.patch
and it can be found in the queue-4.1 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 Tue Jan 26 21:37:04 PST 2016
From: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Date: Thu, 7 Jan 2016 11:26:53 +0100
Subject: vxlan: fix test which detect duplicate vxlan iface

From: Nicolas Dichtel <nicolas.dichtel@6wind.com>

[ Upstream commit 07b9b37c227cb8d88d478b4a9c5634fee514ede1 ]

When a vxlan interface is created, the driver checks that there is not
another vxlan interface with the same properties. To do this, it checks
the existing vxlan udp socket. Since commit 1c51a9159dde, the creation of
the vxlan socket is done only when the interface is set up, thus it breaks
that test.

Example:
$ ip l a vxlan10 type vxlan id 10 group 239.0.0.10 dev eth0 dstport 0
$ ip l a vxlan11 type vxlan id 10 group 239.0.0.10 dev eth0 dstport 0
$ ip -br l | grep vxlan
vxlan10          DOWN           f2:55:1c:6a:fb:00 <BROADCAST,MULTICAST>
vxlan11          DOWN           7a:cb:b9:38:59:0d <BROADCAST,MULTICAST>

Instead of checking sockets, let's loop over the vxlan iface list.

Fixes: 1c51a9159dde ("vxlan: fix race caused by dropping rtnl_unlock")
Reported-by: Thomas Faivre <thomas.faivre@6wind.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/vxlan.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -2581,7 +2581,7 @@ static int vxlan_newlink(struct net *src
 			 struct nlattr *tb[], struct nlattr *data[])
 {
 	struct vxlan_net *vn = net_generic(src_net, vxlan_net_id);
-	struct vxlan_dev *vxlan = netdev_priv(dev);
+	struct vxlan_dev *vxlan = netdev_priv(dev), *tmp;
 	struct vxlan_rdst *dst = &vxlan->default_dst;
 	__u32 vni;
 	int err;
@@ -2714,9 +2714,13 @@ static int vxlan_newlink(struct net *src
 	if (data[IFLA_VXLAN_REMCSUM_NOPARTIAL])
 		vxlan->flags |= VXLAN_F_REMCSUM_NOPARTIAL;
 
-	if (vxlan_find_vni(src_net, vni, use_ipv6 ? AF_INET6 : AF_INET,
-			   vxlan->dst_port, vxlan->flags)) {
-		pr_info("duplicate VNI %u\n", vni);
+	list_for_each_entry(tmp, &vn->vxlan_list, next) {
+		if (tmp->default_dst.remote_vni == vni &&
+		    (tmp->default_dst.remote_ip.sa.sa_family == AF_INET6 ||
+		     tmp->saddr.sa.sa_family == AF_INET6) == use_ipv6 &&
+		    tmp->dst_port == vxlan->dst_port &&
+		    (tmp->flags & VXLAN_F_RCV_FLAGS) ==
+		    (vxlan->flags & VXLAN_F_RCV_FLAGS))
 		return -EEXIST;
 	}
 


Patches currently in stable-queue which might be from nicolas.dichtel@6wind.com are

queue-4.1/vxlan-fix-test-which-detect-duplicate-vxlan-iface.patch
queue-4.1/utf-8-q-veth-20don-e2-80-99t-20modify-20ip-5fsum-utf-8-q-med-20doing-20so-20treats-20packets-20with-20bad-20checksums-utf-8-q-20as-20good.patch