[ 3.5.y.z extended stable ] Patch "net: inet_diag -- Return error code if protocol handler is" has been added to staging queue

[Herton Ronaldo Krzesinski]

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

    net: inet_diag -- Return error code if protocol handler is

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From 84aa45796d11945bc12b8269b9fdb577ed337e1a Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov at openvz.org>
Date: Sat, 3 Nov 2012 09:30:34 +0000
Subject: [PATCH] net: inet_diag -- Return error code if protocol handler is
 missed

commit cacb6ba0f36ab14a507f4ee7697e8332899015d2 upstream.

We've observed that in case if UDP diag module is not
supported in kernel the netlink returns NLMSG_DONE without
notifying a caller that handler is missed.

This patch makes __inet_diag_dump to return error code instead.

So as example it become possible to detect such situation
and handle it gracefully on userspace level.

Signed-off-by: Cyrill Gorcunov <gorcunov at openvz.org>
CC: David Miller <davem at davemloft.net>
CC: Eric Dumazet <eric.dumazet at gmail.com>
CC: Pavel Emelyanov <xemul at parallels.com>
Acked-by: Pavel Emelyanov <xemul at parallels.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/ipv4/inet_diag.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 46d1e71..1bfc104 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -875,13 +875,16 @@ static int __inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 		struct inet_diag_req_v2 *r, struct nlattr *bc)
 {
 	const struct inet_diag_handler *handler;
+	int err = 0;

 	handler = inet_diag_lock_handler(r->sdiag_protocol);
 	if (!IS_ERR(handler))
 		handler->dump(skb, cb, r, bc);
+	else
+		err = PTR_ERR(handler);
 	inet_diag_unlock_handler(handler);

-	return skb->len;
+	return err ? : skb->len;
 }

 static int inet_diag_dump(struct sk_buff *skb, struct netlink_callback *cb)
--
1.7.9.5