[PATCH 3.18 12/20] bridge: dont send notification when skb->len == 0 in rtnl_bridge_notify

Greg Kroah-Hartman
2015-02-25T02:19:20Z

From: Roopa Prabhu <roopa@cumulusnetworks.com>

[ 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>
---
net/core/rtnetlink.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2770,12 +2770,16 @@ static int rtnl_bridge_notify(struct net
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;
}