staging: gigaset: add endpoint-type sanity check

Add missing endpoint-type sanity checks to probe.

This specifically prevents a warning in USB core on URB submission when
fuzzing USB descriptors.
Signed-off-by: Johan Hovold <johan@kernel.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191202085610.12719-4-johan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/isdn/gigaset/usb-gigaset.c

@@ -705,6 +705,12 @@ static int gigaset_probe(struct usb_interface *interface,
 
 	endpoint = &hostif->endpoint[0].desc;
 
+	if (!usb_endpoint_is_bulk_out(endpoint)) {
+		dev_err(&interface->dev, "missing bulk-out endpoint\n");
+		retval = -ENODEV;
+		goto error;
+	}
+
 	buffer_size = le16_to_cpu(endpoint->wMaxPacketSize);
 	ucs->bulk_out_size = buffer_size;
 	ucs->bulk_out_epnum = usb_endpoint_num(endpoint);
@@ -724,6 +730,12 @@ static int gigaset_probe(struct usb_interface *interface,
 
 	endpoint = &hostif->endpoint[1].desc;
 
+	if (!usb_endpoint_is_int_in(endpoint)) {
+		dev_err(&interface->dev, "missing int-in endpoint\n");
+		retval = -ENODEV;
+		goto error;
+	}
+
 	ucs->busy = 0;
 
 	ucs->read_urb = usb_alloc_urb(0, GFP_KERNEL);