static long vop_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
{
	struct vop_vdev *vdev = f->private_data;
	struct vop_info *vi = vdev->vi;
	void __user *argp = (void __user *)arg;
	int ret;

	switch (cmd) {
	case MIC_VIRTIO_ADD_DEVICE:
	{
		struct mic_device_desc dd, *dd_config;

		if (copy_from_user(&dd, argp, sizeof(dd)))
			return -EFAULT;

		if (mic_aligned_desc_size(&dd) > MIC_MAX_DESC_BLK_SIZE ||
		    dd.num_vq > MIC_MAX_VRINGS)
			return -EINVAL;

		dd_config = kzalloc(mic_desc_size(&dd), GFP_KERNEL);
		if (!dd_config)
			return -ENOMEM;
		if (copy_from_user(dd_config, argp, mic_desc_size(&dd))) {
 			ret = -EFAULT;
 			goto free_ret;
 		}
 		mutex_lock(&vdev->vdev_mutex);
 		mutex_lock(&vi->vop_mutex);
 		ret = vop_virtio_add_device(vdev, dd_config);
		if (ret)
			goto unlock_ret;
		list_add_tail(&vdev->list, &vi->vdev_list);
unlock_ret:
		mutex_unlock(&vi->vop_mutex);
		mutex_unlock(&vdev->vdev_mutex);
free_ret:
		kfree(dd_config);
		return ret;
	}
	case MIC_VIRTIO_COPY_DESC:
	{
		struct mic_copy_desc copy;

		mutex_lock(&vdev->vdev_mutex);
		ret = vop_vdev_inited(vdev);
		if (ret)
			goto _unlock_ret;

		if (copy_from_user(&copy, argp, sizeof(copy))) {
			ret = -EFAULT;
			goto _unlock_ret;
		}

		ret = vop_virtio_copy_desc(vdev, &copy);
		if (ret < 0)
			goto _unlock_ret;
		if (copy_to_user(
			&((struct mic_copy_desc __user *)argp)->out_len,
			&copy.out_len, sizeof(copy.out_len)))
			ret = -EFAULT;
_unlock_ret:
		mutex_unlock(&vdev->vdev_mutex);
		return ret;
	}
	case MIC_VIRTIO_CONFIG_CHANGE:
	{
		void *buf;

		mutex_lock(&vdev->vdev_mutex);
		ret = vop_vdev_inited(vdev);
		if (ret)
			goto __unlock_ret;
		buf = kzalloc(vdev->dd->config_len, GFP_KERNEL);
		if (!buf) {
			ret = -ENOMEM;
			goto __unlock_ret;
		}
		if (copy_from_user(buf, argp, vdev->dd->config_len)) {
			ret = -EFAULT;
			goto done;
		}
		ret = vop_virtio_config_change(vdev, buf);
done:
		kfree(buf);
__unlock_ret:
		mutex_unlock(&vdev->vdev_mutex);
		return ret;
	}
	default:
		return -ENOIOCTLCMD;
	};
	return 0;
}

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.