diff --git a/refpolicy/policy/modules/system/domain.if b/refpolicy/policy/modules/system/domain.if
index f41a1580..a3388c34 100644
--- a/refpolicy/policy/modules/system/domain.if
+++ b/refpolicy/policy/modules/system/domain.if
@@ -1,4 +1,6 @@
 # Copyright (C) 2005 Tresys Technology, LLC
+## <module name="domain" layer="system">
+## <summary>Core policy for domains.</summary>
 
 ########################################
 #
@@ -131,6 +133,27 @@ attribute domain;
 class process signal;
 ')
 
+########################################
+## <interface name="domain_signull_all_domains">
+##	<description>
+##		Send a null signal to all domains.
+##	</description>
+##	<parameter name="domain">
+##		The type of the process performing this action.
+##	</parameter>
+##	<infoflow type="write" weight="1"/>
+## </interface>
+#
+define(`domain_signull_all_domains',`
+requires_block_template(`$0'_depend)
+allow $1 domain:process signull;
+')
+
+define(`domain_signull_all_domains_depend',`
+attribute domain;
+class process signull;
+')
+
 ########################################
 #
 # domain_kill_all_domains(domain)
@@ -201,3 +224,5 @@ define(`domain_read_all_entrypoint_programs_depend',`
 attribute entry_type;
 class file { getattr read };
 ')
+
+## </module>