USB: gadget: validate endpoint index for xilinx udc

Assure that host may not manipulate the index to point
past endpoint array.

Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/udc-xilinx.c

@@ -1615,6 +1615,8 @@ static void xudc_getstatus(struct xusb_udc *udc)
 		break;
 	case USB_RECIP_ENDPOINT:
 		epnum = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
+		if (epnum >= XUSB_MAX_ENDPOINTS)
+			goto stall;
 		target_ep = &udc->ep[epnum];
 		epcfgreg = udc->read_fn(udc->addr + target_ep->offset);
 		halt = epcfgreg & XUSB_EP_CFG_STALL_MASK;
@@ -1682,6 +1684,10 @@ static void xudc_set_clear_feature(struct xusb_udc *udc)
 	case USB_RECIP_ENDPOINT:
 		if (!udc->setup.wValue) {
 			endpoint = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
+			if (endpoint >= XUSB_MAX_ENDPOINTS) {
+				xudc_ep0_stall(udc);
+				return;
+			}
 			target_ep = &udc->ep[endpoint];
 			outinbit = udc->setup.wIndex & USB_ENDPOINT_DIR_MASK;
 			outinbit = outinbit >> 7;