[ 3.8.y.z extended stable ] Patch "ipv4: fix redirect handling for TCP packets" has been added to staging queue

[Kamal Mostafa]

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

    ipv4: fix redirect handling for TCP packets

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.4.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 4cfb47f5f14a3714b5102b1c317f15ca76da7108 Mon Sep 17 00:00:00 2001
From: Michal Kubecek <mkubecek at suse.cz>
Date: Tue, 28 May 2013 08:26:49 +0200
Subject: ipv4: fix redirect handling for TCP packets

[ Upstream commit f96ef988cc603487c03a6de07807b06cbe641829 ]

Unlike ipv4_redirect() and ipv4_sk_redirect(), ip_do_redirect()
doesn't call __build_flow_key() directly but via
ip_rt_build_flow_key() wrapper. This leads to __build_flow_key()
getting pointer to IPv4 header of the ICMP redirect packet
rather than pointer to the embedded IPv4 header of the packet
initiating the redirect.

As a result, handling of ICMP redirects initiated by TCP packets
is broken. Issue was introduced by

	4895c771c ("ipv4: Add FIB nexthop exceptions.")

Signed-off-by: Michal Kubecek <mkubecek at suse.cz>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 net/ipv4/route.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index a0fcc47..70da494 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -741,10 +741,15 @@ static void ip_do_redirect(struct dst_entry *dst, struct sock *sk, struct sk_buf
 {
 	struct rtable *rt;
 	struct flowi4 fl4;
+	const struct iphdr *iph = (const struct iphdr *) skb->data;
+	int oif = skb->dev->ifindex;
+	u8 tos = RT_TOS(iph->tos);
+	u8 prot = iph->protocol;
+	u32 mark = skb->mark;

 	rt = (struct rtable *) dst;

-	ip_rt_build_flow_key(&fl4, sk, skb);
+	__build_flow_key(&fl4, sk, iph, oif, tos, prot, mark, 0);
 	__ip_do_redirect(rt, skb, &fl4, true);
 }

--
1.8.1.2