IB/mlx4: Verify port number in flow steering create flow

commit 5533c18a upstream.

In procedure mlx4_ib_create_flow, passing an invalid port number
will cause an out-of-bounds array access. Data passed to this procedure
can come from user-space.  Therefore, need to validate port number
before proceeding onwards.

Note that we check against the number of physical ports declared at
the verbs (ib core) level; When bonding is active, the verbs level
sees one physical port, even though the low-level driver sees two ports.

Fixes: f77c0162 ("IB/mlx4: Add receive flow steering support")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Reviewed-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
[bwh: Backported to 3.16:
 - Adjust context
 - Function returns an integer, not a pointer/error]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/infiniband/hw/mlx4/main.c

@@ -1016,6 +1016,9 @@ static int __mlx4_ib_create_flow(struct ib_qp *qp, struct ib_flow_attr *flow_att
 		[IB_FLOW_DOMAIN_NIC] = MLX4_DOMAIN_NIC,
 	};
 
+	if (flow_attr->port < 1 || flow_attr->port > qp->device->phys_port_cnt)
+		return -EINVAL;
+
 	if (flow_attr->priority > MLX4_IB_FLOW_MAX_PRIO) {
 		pr_err("Invalid priority value %d\n", flow_attr->priority);
 		return -EINVAL;