[PATCH v2 2/2] drm/uapi: add explicit virtgpu context debug name

[Dmitry Osipenko]

On 10/18/23 20:04, Gurchetan Singh wrote:
> +
> +			ret = strncpy_from_user(vfpriv->debug_name,
> +						u64_to_user_ptr(value),
> +						DEBUG_NAME_MAX_LEN);
> +
> +			if (ret < 0) {
> +				ret = -EFAULT;
> +				goto out_unlock;
> +			}
> +
> +			/*
> +			 * strncpy_from_user doesn't copy the NULL terminator when
> +			 * DEBUG_NAME_MAX_LEN bytes is copied. Fix that here.
> +			 */
> +			if (ret == DEBUG_NAME_MAX_LEN)
> +				vfpriv->debug_name[DEBUG_NAME_MAX_LEN - 1] = '\0';

If you'll copy DEBUG_NAME_MAX_LEN-1 bytes, then string will be always
NULL-terminated. It is a standard practice for strncpy usage to do it
like this:

	ret = strncpy_from_user(vfpriv->debug_name,
				u64_to_user_ptr(value),
				DEBUG_NAME_MAX_LEN - 1);
-- 
Best regards,
Dmitry