usb: gadget: uvc: Prevent buffer overflow in setup handler

Setup function uvc_function_setup permits control transfer
requests with up to 64 bytes of payload (UVC_MAX_REQUEST_SIZE),
data stage handler for OUT transfer uses memcpy to copy req->actual
bytes to uvc_event->data.data array of size 60. This may result
in an overflow of 4 bytes.

Fixes: cdda479f15cd ("USB gadget: video class function driver")
Cc: stable <stable@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Link: https://lore.kernel.org/r/20221206141301.51305-1-szymon.heidrich@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
index 6e13162..32f2c16 100644 (file)
--- a/drivers/usb/gadget/function/f_uvc.c
+++ b/drivers/usb/gadget/function/f_uvc.c
@@ -213,8 +213,9 @@ uvc_function_ep0_complete(struct usb_ep *ep, struct usb_request *req)
 
                memset(&v4l2_event, 0, sizeof(v4l2_event));
                v4l2_event.type = UVC_EVENT_DATA;
-               uvc_event->data.length = req->actual;
-               memcpy(&uvc_event->data.data, req->buf, req->actual);
+               uvc_event->data.length = min_t(unsigned int, req->actual,
+                       sizeof(uvc_event->data.data));
+               memcpy(&uvc_event->data.data, req->buf, uvc_event->data.length);
                v4l2_event_queue(&uvc->vdev, &v4l2_event);
        }
 }