Borrowed from debian, allows users in netdev group to control wpa-supplicant
via D-Bus.

Description: Debian does not use pam_console but uses group membership
 to control access to D-Bus. Activating both options in the conf file
 makes it work on Debian and Ubuntu.
Author: Michael Biebl <biebl@debian.org>
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=15;bug=412179
---
--- a/wpa_supplicant/dbus/dbus-wpa_supplicant.conf
+++ b/wpa_supplicant/dbus/dbus-wpa_supplicant.conf
@@ -14,6 +14,11 @@
                 <allow send_interface="fi.w1.wpa_supplicant1"/>
                 <allow receive_sender="fi.w1.wpa_supplicant1" receive_type="signal"/>
         </policy>
+        <policy group="netdev">
+                <allow send_destination="fi.w1.wpa_supplicant1"/>
+                <allow send_interface="fi.w1.wpa_supplicant1"/>
+                <allow receive_sender="fi.w1.wpa_supplicant1" receive_type="signal"/>
+        </policy>
         <policy context="default">
                 <deny own="fi.epitest.hostap.WPASupplicant"/>
                 <deny send_destination="fi.epitest.hostap.WPASupplicant"/>