[PATCH 3.4 11/23] tipc: clear next-pointer of message fragments before reassembly

Greg Kroah-Hartman
2014-07-26T19:02:40Z

From: Jon Paul Maloy <jon.maloy@ericsson.com>

[ 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@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/tipc/bcast.c | 1 +
1 file changed, 1 insertion(+)

--- a/net/tipc/bcast.c
+++ b/net/tipc/bcast.c
@@ -541,6 +541,7 @@ receive:

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