This is a note to let you know that I've just added the patch titled

    tcp: incoming connections might use wrong route under synflood

to the 3.0-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tcp-incoming-connections-might-use-wrong-route-under-synflood.patch
and it can be found in the queue-3.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 7293e360700498d14aa0530071fc29819f242e74 Mon Sep 17 00:00:00 2001
From: Dmitry Popov <[email protected]>
Date: Thu, 11 Apr 2013 08:55:07 +0000
Subject: tcp: incoming connections might use wrong route under synflood


From: Dmitry Popov <[email protected]>

[ Upstream commit d66954a066158781ccf9c13c91d0316970fe57b6 ]

There is a bug in cookie_v4_check (net/ipv4/syncookies.c):
        flowi4_init_output(&fl4, 0, sk->sk_mark, RT_CONN_FLAGS(sk),
                           RT_SCOPE_UNIVERSE, IPPROTO_TCP,
                           inet_sk_flowi_flags(sk),
                           (opt && opt->srr) ? opt->faddr : ireq->rmt_addr,
                           ireq->loc_addr, th->source, th->dest);

Here we do not respect sk->sk_bound_dev_if, therefore wrong dst_entry may be
taken. This dst_entry is used by new socket (get_cookie_sock ->
tcp_v4_syn_recv_sock), so its packets may take the wrong path.

Signed-off-by: Dmitry Popov <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 net/ipv4/syncookies.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -345,8 +345,8 @@ struct sock *cookie_v4_check(struct sock
         * hasn't changed since we received the original syn, but I see
         * no easy way to do this.
         */
-       flowi4_init_output(&fl4, 0, sk->sk_mark, RT_CONN_FLAGS(sk),
-                          RT_SCOPE_UNIVERSE, IPPROTO_TCP,
+       flowi4_init_output(&fl4, sk->sk_bound_dev_if, sk->sk_mark,
+                          RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE, IPPROTO_TCP,
                           inet_sk_flowi_flags(sk),
                           (opt && opt->srr) ? opt->faddr : ireq->rmt_addr,
                           ireq->loc_addr, th->source, th->dest);


Patches currently in stable-queue which might be from [email protected] are

queue-3.0/tcp-incoming-connections-might-use-wrong-route-under-synflood.patch
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