--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mod_s2s_auth_dnssec_srv/mod_s2s_auth_dnssec_srv.lua	Thu May 09 13:36:53 2013 +0200
@@ -0,0 +1,31 @@
+-- Copyright (C) 2013 Kim Alvefur
+-- This file is MIT/X11 licensed.
+--
+-- Implements Secure Delegation using DNS SRV as described in 
+-- http://tools.ietf.org/html/draft-miller-xmpp-dnssec-prooftype
+--
+-- Dependecies:
+-- Prosody above hg:43059357b2f0
+-- DNSSEC-validating DNS resolver
+--  https://github.com/Zash/luaunbound
+--   libunbound binding using LuaJIT FFI
+
+module:set_global();
+
+local nameprep = require"util.encodings".stringprep.nameprep;
+local to_unicode = require"util.encodings".idna.to_unicode;
+local cert_verify_identity = require "util.x509".verify_identity;
+
+module:hook("s2s-check-certificate", function(event)
+	local session, cert = event.session, event.cert;
+
+	if session.cert_identity_status ~= "valid" and session.srv_choice
+	and session.srv_hosts.answer and session.srv_hosts.answer.secure then
+		local srv_target = nameprep(to_unicode(session.srv_hosts[session.srv_choice].target:gsub("%.?$","")));
+		(session.log or module._log)("debug", "Comparing certificate with Secure SRV target %s", srv_target);
+		if srv_target and cert_verify_identity(srv_target, "xmpp-server", cert) then
+			(session.log or module._log)("info", "Certificate matches Secure SRV target %s", srv_target);
+			session.cert_identity_status = "valid";
+		end
+	end
+end);