smbprovider/etc/dbus-1/org.chromium.SmbProvider.conf

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
 "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<!--
  Copyright 2017 The Chromium OS Authors. All rights reserved.
  Use of this source code is governed by a BSD-style license that can be
  found in the LICENSE file.
-->

<busconfig>
  <policy user="smbproviderd">
    <allow own="org.chromium.SmbProvider"/>
  </policy>

  <policy user="chronos">
    <allow send_destination="org.chromium.SmbProvider"
           send_interface="org.chromium.SmbProvider"
           send_member="Mount"/>
    <allow send_destination="org.chromium.SmbProvider"
           send_interface="org.chromium.SmbProvider"
           send_member="Unmount"/>
    <allow send_destination="org.chromium.SmbProvider"
           send_interface="org.chromium.SmbProvider"
           send_member="ReadDirectory"/>
    <allow send_destination="org.chromium.SmbProvider"
           send_interface="org.chromium.SmbProvider"
           send_member="GetMetadataEntry"/>
  </policy>
</busconfig>