UBUNTU: SAUCE: (no-up) rds_ib_send() -- prevent local pings triggering BUG_ON()

Pining localhost on an infiniband connection can trigger a BUG_ON()
and cause a denial of service.

Fix identified by comparison of the RHEL source rpms.

CVE-2012-2372
BugLink: http://bugs.launchpad.net/bugs/1016299Signed-off-by: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

net/rds/ib_send.c

@@ -502,7 +502,7 @@ int rds_ib_xmit(struct rds_connection *conn, struct rds_message *rm,
 	int flow_controlled = 0;
 	int nr_sig = 0;
 
-	BUG_ON(off % RDS_FRAG_SIZE);
+	BUG_ON(!conn->c_loopback && off % RDS_FRAG_SIZE);
 	BUG_ON(hdr_off != 0 && hdr_off != sizeof(struct rds_header));
 
 	/* Do not send cong updates to IB loopback */