root@buzz:/etc/dbus-1/system.d# more system-tools-backends.conf 
<!DOCTYPE busconfig PUBLIC
 "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<busconfig>

  <policy context="default">
    <!-- just for testing purposes, only root will
         be able to actually change configuration -->
    <allow own="org.freedesktop.SystemToolsBackends"/>
    <deny send_interface="org.freedesktop.SystemToolsBackends"/>
    <deny send_destination="org.freedesktop.SystemToolsBackends"/>
  </policy>

  <policy user="0">
    <allow send_interface="org.freedesktop.SystemToolsBackends"/>
    <allow send_destination="org.freedesktop.SystemToolsBackends"/>
  </policy>

  <policy group="stb-admin">
    <allow send_interface="org.freedesktop.SystemToolsBackends"/>
    <allow send_destination="org.freedesktop.SystemToolsBackends"/>
  </policy>
</busconfig>
root@buzz:/etc/dbus-1/system.d#