[PATCH 3.13.y-ckt 010/143] bridge: dont send notification when skb->len == 0 in rtnl_bridge_notify

From: Kamal Mostafa
Date: Tue Mar 31 2015 - 16:31:56 EST


3.13.11-ckt18 -stable review patch. If anyone has any objections, please let me know.

------------------

From: Roopa Prabhu <roopa@xxxxxxxxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
net/core/rtnetlink.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 7dca4b4..f48db99 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2542,12 +2542,16 @@ 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;
}

--
1.9.1

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