Re: [PATCH v3] usb: gadget: uvc: Prevent buffer overflow in setup handler
From: Laurent Pinchart
Date: Tue Dec 06 2022 - 16:21:57 EST
Hi Szymon,
Thank you for the patch.
On Tue, Dec 06, 2022 at 03:13:01PM +0100, Szymon Heidrich wrote:
> 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")
> Signed-off-by: Szymon Heidrich <szymon.heidrich@xxxxxxxxx>
Good catch.
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> ---
> V1 -> V2: Corrected commit message and changed ?: in favor of min_t
> V2 -> V3: Added fixes tag
>
> drivers/usb/gadget/function/f_uvc.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c
> index 6e196e061..4419b7972 100644
> --- a/drivers/usb/gadget/function/f_uvc.c
> +++ b/drivers/usb/gadget/function/f_uvc.c
> @@ -216,8 +216,9 @@ 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);
> }
> }
--
Regards,
Laurent Pinchart