usb: gadget: storage: check for valid USB_BULK_GET_MAX_LUN_REQUEST

The latest USB-IF CV tester checks for a valid length for this
request.
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/f_mass_storage.c

@@ -639,7 +639,8 @@ static int fsg_setup(struct usb_function *f,
 		if (ctrl->bRequestType !=
 		    (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
 			break;
-		if (w_index != fsg->interface_number || w_value != 0)
+		if (w_index != fsg->interface_number || w_value != 0 ||
+				w_length != 1)
 			return -EDOM;
 		VDBG(fsg, "get max LUN\n");
 		*(u8 *)req->buf = fsg->common->nluns - 1;

drivers/usb/gadget/file_storage.c

@@ -875,7 +875,7 @@ static int class_setup_req(struct fsg_dev *fsg,
 			if (ctrl->bRequestType != (USB_DIR_IN |
 					USB_TYPE_CLASS | USB_RECIP_INTERFACE))
 				break;
-			if (w_index != 0 || w_value != 0) {
+			if (w_index != 0 || w_value != 0 || w_length != 1) {
 				value = -EDOM;
 				break;
 			}