static ssize_t wdm_write
(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
	u8 *buf;
	int rv = -EMSGSIZE, r, we;
	struct wdm_device *desc = file->private_data;
	struct usb_ctrlrequest *req;

	if (count > desc->wMaxCommand)
		count = desc->wMaxCommand;

	spin_lock_irq(&desc->iuspin);
	we = desc->werr;
	desc->werr = 0;
	spin_unlock_irq(&desc->iuspin);
	if (we < 0)
		return -EIO;

	buf = kmalloc(count, GFP_KERNEL);
	if (!buf) {
		rv = -ENOMEM;
		goto outnl;
	}

	r = copy_from_user(buf, buffer, count);
	if (r > 0) {
		kfree(buf);
		rv = -EFAULT;
		goto outnl;
	}

	/* concurrent writes and disconnect */
	r = mutex_lock_interruptible(&desc->wlock);
	rv = -ERESTARTSYS;
	if (r) {
		kfree(buf);
		goto outnl;
	}

	if (test_bit(WDM_DISCONNECTING, &desc->flags)) {
		kfree(buf);
		rv = -ENODEV;
		goto outnp;
	}

	r = usb_autopm_get_interface(desc->intf);
	if (r < 0) {
		kfree(buf);
		rv = usb_translate_errors(r);
		goto outnp;
	}

	if (!(file->f_flags & O_NONBLOCK))
		r = wait_event_interruptible(desc->wait, !test_bit(WDM_IN_USE,
								&desc->flags));
	else
		if (test_bit(WDM_IN_USE, &desc->flags))
			r = -EAGAIN;

	if (test_bit(WDM_RESETTING, &desc->flags))
		r = -EIO;

	if (r < 0) {
		kfree(buf);
		rv = r;
		goto out;
	}

	req = desc->orq;
	usb_fill_control_urb(
		desc->command,
		interface_to_usbdev(desc->intf),
		/* using common endpoint 0 */
		usb_sndctrlpipe(interface_to_usbdev(desc->intf), 0),
		(unsigned char *)req,
		buf,
		count,
		wdm_out_callback,
		desc
	);

	req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS |
			     USB_RECIP_INTERFACE);
	req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
	req->wValue = 0;
	req->wIndex = desc->inum;
	req->wLength = cpu_to_le16(count);
	set_bit(WDM_IN_USE, &desc->flags);
	desc->outbuf = buf;

	rv = usb_submit_urb(desc->command, GFP_KERNEL);
	if (rv < 0) {
		kfree(buf);
		desc->outbuf = NULL;
		clear_bit(WDM_IN_USE, &desc->flags);
		dev_err(&desc->intf->dev, "Tx URB error: %d\n", rv);
		rv = usb_translate_errors(rv);
	} else {
		dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
			req->wIndex);
	}
out:
	usb_autopm_put_interface(desc->intf);
outnp:
	mutex_unlock(&desc->wlock);
outnl:
	return rv < 0 ? rv : count;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.