[3.11.y.z extended stable] Patch "tipc: clear 'next'-pointer of message fragments before reassembly" has been added to staging queue

[Luis Henriques]

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

    tipc: clear 'next'-pointer of message fragments before reassembly

to the linux-3.11.y-queue branch of the 3.11.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-3.11.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 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From a89ea9fdbe6562547f4e4078291af0f132f0db66 Mon Sep 17 00:00:00 2001
From: Jon Paul Maloy <jon.maloy at ericsson.com>
Date: Fri, 11 Jul 2014 08:45:27 -0400
Subject: tipc: clear 'next'-pointer of message fragments before reassembly

commit 999417549c16dd0e3a382aa9f6ae61688db03181 upstream.

If the 'next' pointer of the last fragment buffer in a message is not
zeroed before reassembly, we risk ending up with a corrupt message,
since the reassembly function itself isn't doing this.

Currently, when a buffer is retrieved from the deferred queue of the
broadcast link, the next pointer is not cleared, with the result as
described above.

This commit corrects this, and thereby fixes a bug that may occur when
long broadcast messages are transmitted across dual interfaces. The bug
has been present since 40ba3cdf542a469aaa9083fa041656e59b109b90 ("tipc:
message reassembly using fragment chain")

This commit should be applied to both net and net-next.

Signed-off-by: Jon Maloy <jon.maloy at ericsson.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/tipc/bcast.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/tipc/bcast.c b/net/tipc/bcast.c
index 716de1ac6cb5..6ef89256b2fb 100644
--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -531,6 +531,7 @@ receive:

 		buf = node->bclink.deferred_head;
 		node->bclink.deferred_head = buf->next;
+		buf->next = NULL;
 		node->bclink.deferred_size--;
 		goto receive;
 	}
--
1.9.1