**Exception for grub2**

For Ubuntu 14.04, the permissions on ``/boot/grub/grub.cfg`` will be set to
``0644``.

Ubuntu 16.04 and CentOS 7 use grub2. The configuration files in ``/boot/grub2``
are regenerated when new kernels are installed or when the root user
regenerates the configuration file. File ownership and permissions are set
appropriately after each of these events.