IB/core: Fix a potential array overrun in CMA and SA agent

commit 2fa2d4fb upstream.

Fix array overrun when going over callback table.
In declaration of callback table, the max size isn't provided and
in registration phase, it is provided.

There is potential scenario where a new operation is added
and it is not supported by current client. The acceptance of
such operation by ib_netlink will cause to array overrun.

Fixes: 809d5fc9 ("infiniband: pass rdma_cm module to netlink_dump_start")
Fixes: b493d91d ("iwcm: common code for port mapper")
Fixes: 2ca546b9 ("IB/sa: Route SA pathrecord query through netlink")
Signed-off-by: Mark Bloch <markb@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.16:
 - Only cma.c needs to be fixed
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/infiniband/core/cma.c

@@ -3679,7 +3679,8 @@ static int __init cma_init(void)
 	if (ret)
 		goto err;
 
-	if (ibnl_add_client(RDMA_NL_RDMA_CM, RDMA_NL_RDMA_CM_NUM_OPS, cma_cb_table))
+	if (ibnl_add_client(RDMA_NL_RDMA_CM, ARRAY_SIZE(cma_cb_table),
+			    cma_cb_table))
 		printk(KERN_WARNING "RDMA CMA: failed to add netlink callback\n");
 
 	return 0;