static int usbhid_set_raw_report(struct hid_device *hid, unsigned int reportnum,
				 __u8 *buf, size_t count, unsigned char rtype)
{
	struct usbhid_device *usbhid = hid->driver_data;
	struct usb_device *dev = hid_to_usb_dev(hid);
	struct usb_interface *intf = usbhid->intf;
	struct usb_host_interface *interface = intf->cur_altsetting;
	int ret, skipped_report_id = 0;

	/* Byte 0 is the report number. Report data starts at byte 1.*/
	if ((rtype == HID_OUTPUT_REPORT) &&
	    (hid->quirks & HID_QUIRK_SKIP_OUTPUT_REPORT_ID))
		buf[0] = 0;
	else
		buf[0] = reportnum;

	if (buf[0] == 0x0) {
		/* Don't send the Report ID */
		buf++;
		count--;
		skipped_report_id = 1;
	}

	ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
			HID_REQ_SET_REPORT,
			USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
			((rtype + 1) << 8) | reportnum,
			interface->desc.bInterfaceNumber, buf, count,
			USB_CTRL_SET_TIMEOUT);
	/* count also the report id, if this was a numbered report. */
	if (ret > 0 && skipped_report_id)
		ret++;

	return ret;
}

The product reads data past the end, or before the beginning, of the intended buffer.