dbus: Add dbus-daemon policy configuration

src/iwd.conf

@@ -0,0 +1,23 @@
+<!-- This configuration file specifies the required security policies
+     for iNet Wireless Daemon to work. -->
+
+<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
+ "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
+<busconfig>
+
+  <!-- ../system.conf have denied everything, so we just punch some holes -->
+
+  <policy user="root">
+    <allow own="net.connman.iwd"/>
+    <allow send_destination="net.connman.iwd"/>
+  </policy>
+
+  <policy at_console="true">
+    <allow send_destination="net.connman.iwd"/>
+  </policy>
+
+  <policy context="default">
+    <deny send_destination="net.connman.iwd"/>
+  </policy>
+
+</busconfig>