[PATCH] usb: gadget: udc-xilinx: validate ep number before indexing rambase[]

[Sergio Perez Gonzalez <sperezglz@gmail.com>]

Issue flagged by coverity. The size of the rambase array is 8,
usb_enpoint_num() can return 0 to 15, prevent out of bounds reads.

Link: https://scan7.scan.coverity.com/#/project-view/53936/11354?selectedIssue=1644635
Signed-off-by: Sergio Perez Gonzalez <sperezglz@gmail.com>
---
 drivers/usb/gadget/udc/udc-xilinx.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/usb/gadget/udc/udc-xilinx.c b/drivers/usb/gadget/udc/udc-xilinx.c
index 8d803a612bb1..0c3714de2e3b 100644
--- a/drivers/usb/gadget/udc/udc-xilinx.c
+++ b/drivers/usb/gadget/udc/udc-xilinx.c
@@ -814,6 +814,12 @@ static int __xudc_ep_enable(struct xusb_ep *ep,
 	ep->is_in = ((desc->bEndpointAddress & USB_DIR_IN) != 0);
 	/* Bit 3...0:endpoint number */
 	ep->epnumber = usb_endpoint_num(desc);
+	if (ep->epnumber >= XUSB_MAX_ENDPOINTS) {
+		dev_dbg(udc->dev, "bad endpoint index %d: only 0 to %d supported\n",
+				ep->epnumber, (XUSB_MAX_ENDPOINTS - 1));
+		return -EINVAL;
+	}
+
 	ep->desc = desc;
 	ep->ep_usb.desc = desc;
 	tmp = usb_endpoint_type(desc);
-- 
2.43.0