IB/srpt: Verify port numbers in srpt_event_handler()

Verify whether port numbers are in the expected range before using
these as an array index. Complain if a port number is out of range.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/ulp/srpt/ib_srpt.c

@@ -134,6 +134,7 @@ static void srpt_event_handler(struct ib_event_handler *handler,
 {
 	struct srpt_device *sdev;
 	struct srpt_port *sport;
+	u8 port_num;
 
 	sdev = ib_get_client_data(event->device, &srpt_client);
 	if (!sdev || sdev->device != event->device)
@@ -144,10 +145,15 @@ static void srpt_event_handler(struct ib_event_handler *handler,
 
 	switch (event->event) {
 	case IB_EVENT_PORT_ERR:
-		if (event->element.port_num <= sdev->device->phys_port_cnt) {
-			sport = &sdev->port[event->element.port_num - 1];
+		port_num = event->element.port_num - 1;
+		if (port_num < sdev->device->phys_port_cnt) {
+			sport = &sdev->port[port_num];
 			sport->lid = 0;
 			sport->sm_lid = 0;
+		} else {
+			WARN(true, "event %d: port_num %d out of range 1..%d\n",
+			     event->event, port_num + 1,
+			     sdev->device->phys_port_cnt);
 		}
 		break;
 	case IB_EVENT_PORT_ACTIVE:
@@ -157,15 +163,19 @@ static void srpt_event_handler(struct ib_event_handler *handler,
 	case IB_EVENT_CLIENT_REREGISTER:
 	case IB_EVENT_GID_CHANGE:
 		/* Refresh port data asynchronously. */
-		if (event->element.port_num <= sdev->device->phys_port_cnt) {
-			sport = &sdev->port[event->element.port_num - 1];
+		port_num = event->element.port_num - 1;
+		if (port_num < sdev->device->phys_port_cnt) {
+			sport = &sdev->port[port_num];
 			if (!sport->lid && !sport->sm_lid)
 				schedule_work(&sport->work);
+		} else {
+			WARN(true, "event %d: port_num %d out of range 1..%d\n",
+			     event->event, port_num + 1,
+			     sdev->device->phys_port_cnt);
 		}
 		break;
 	default:
-		pr_err("received unrecognized IB event %d\n",
-		       event->event);
+		pr_err("received unrecognized IB event %d\n", event->event);
 		break;
 	}
 }