cups.conf

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>
  <!-- Only root can send this message -->
  <policy user="root">
    <allow send_interface="com.redhat.PrinterSpooler"/>
  </policy>

  <!-- Allow any connection to receive the message -->
  <policy context="default">
    <allow receive_interface="com.redhat.PrinterSpooler"/>
  </policy>
</busconfig>