add a xml comment

refpolicy/policy/modules/system/userdomain.if

@@ -1,4 +1,6 @@
 # Copyright (C) 2005 Tresys Technology, LLC
+## <module name="userdomain" layer="system">
+## <summary>Policy for user domains</summary>
 
 ########################################
 #
@@ -791,3 +793,26 @@ allow $1_t domain:socket_class_set getattr;
 allow $1_t eventpollfs_t:file getattr;
 ') dnl endif TODO
 ')
+
+#
+## <interface name="userdomain_use_all_users_file_descriptors">
+##	<description>
+##		Inherit the file descriptors from all user domains
+##	</description>
+##	<parameter name="domain">
+##		The type of the process performing this action.
+##	</parameter>
+##	<infoflow type="read" weight="1"/>
+## </interface>
+#
+define(`userdomain_use_all_users_file_descriptors',`
+requires_block_template(`$0'_depend)
+allow $1 userdomain:fd use;
+')
+
+define(`userdomain_use_all_users_file_descriptors_depend',`
+attribute userdomain;
+class fd use;
+')
+
+## </module>