[PATCH 5.10 05/18] usb: gadget: uvc: Prevent buffer overflow in setup handler

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Szymon Heidrich <szymon.heidrich@gmail.com>

commit 4c92670b16727365699fe4b19ed32013bab2c107 upstream.

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>
---
 drivers/usb/gadget/function/f_uvc.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- 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
 
 		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);
 	}
 }