From: Roopa Prabhu <roopa@cumulusnetworks.com>
Date: Thu, 29 Jan 2015 00:23:11 +0000 (-0800)
Subject: bridge: dont send notification when skb->len == 0 in rtnl_bridge_notify
X-Git-Tag: firefly_0821_release~3679^2~814
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b4faf21b76b2a0cf00e5a75e73efb22a09868b18;p=firefly-linux-kernel-4.4.55.git

bridge: dont send notification when skb->len == 0 in rtnl_bridge_notify

[ Upstream commit 59ccaaaa49b5b096cdc1f16706a9f931416b2332 ]

Reported in: https://bugzilla.kernel.org/show_bug.cgi?id=92081

This patch avoids calling rtnl_notify if the device ndo_bridge_getlink
handler does not return any bytes in the skb.

Alternately, the skb->len check can be moved inside rtnl_notify.

For the bridge vlan case described in 92081, there is also a fix needed
in bridge driver to generate a proper notification. Will fix that in
subsequent patch.

v2: rebase patch on net tree

Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 25c4dd563a79..279b5dcf09ae 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2477,12 +2477,16 @@ static int rtnl_bridge_notify(struct net_device *dev, u16 flags)
 			goto errout;
 	}
 
+	if (!skb->len)
+		goto errout;
+
 	rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
 	return 0;
 errout:
 	WARN_ON(err == -EMSGSIZE);
 	kfree_skb(skb);
-	rtnl_set_sk_err(net, RTNLGRP_LINK, err);
+	if (err)
+		rtnl_set_sk_err(net, RTNLGRP_LINK, err);
 	return err;
 }