File: //etc/dbus-1/system.d/nm-system-settings.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 user="root">
<allow own="org.freedesktop.NetworkManagerSystemSettings"/>
<allow send_destination="org.freedesktop.NetworkManagerSystemSettings"/>
<allow send_interface="org.freedesktop.NetworkManagerSettings"/>
<allow send_interface="org.freedesktop.NetworkManagerSettings.Secrets"/>
</policy>
<policy context="default">
<deny own="org.freedesktop.NetworkManagerSystemSettings"/>
<allow send_destination="org.freedesktop.NetworkManagerSystemSettings"/>
<allow send_interface="org.freedesktop.NetworkManagerSettings"/>
<!-- Only root can get secrets -->
<deny send_interface="org.freedesktop.NetworkManagerSettings.Connection.Secrets"/>
</policy>
<limit name="max_replies_per_connection">512</limit>
</busconfig>