[PATCH 3.10 35/56] tipc: clear next-pointer of message fragments before reassembly

From: Greg Kroah-Hartman
Date: Sat Jul 26 2014 - 15:04:41 EST

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


From: Jon Paul Maloy <jon.maloy@xxxxxxxxxxxx>

[ Upstream commit 999417549c16dd0e3a382aa9f6ae61688db03181 ]

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@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/tipc/bcast.c | 1 +
1 file changed, 1 insertion(+)

--- 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;
goto receive;

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