-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local create_context = require "core.certmanager".create_context;

local rawgetopt = require"core.configmanager".rawget;

local st = require "util.stanza";

local c2s_require_encryption = module:get_option("c2s_require_encryption", module:get_option("require_encryption", true));

local s2s_require_encryption = module:get_option("s2s_require_encryption", true);

local allow_s2s_tls = module:get_option("s2s_allow_encryption") ~= false;

local s2s_secure_auth = module:get_option("s2s_secure_auth");

if s2s_secure_auth and s2s_require_encryption == false then

	module:log("warn", "s2s_secure_auth implies s2s_require_encryption, but s2s_require_encryption is set to false");

	s2s_require_encryption = true;

end

local xmlns_starttls = 'urn:ietf:params:xml:ns:xmpp-tls';

local starttls_attr = { xmlns = xmlns_starttls };

local starttls_initiate= st.stanza("starttls", starttls_attr);

local starttls_proceed = st.stanza("proceed", starttls_attr);

local starttls_failure = st.stanza("failure", starttls_attr);

local c2s_feature = st.stanza("starttls", starttls_attr);

local s2s_feature = st.stanza("starttls", starttls_attr);

if c2s_require_encryption then c2s_feature:tag("required"):up(); end

if s2s_require_encryption then s2s_feature:tag("required"):up(); end

local hosts = prosody.hosts;

local host = hosts[module.host];

local ssl_ctx_c2s, ssl_ctx_s2sout, ssl_ctx_s2sin;

local ssl_cfg_c2s, ssl_cfg_s2sout, ssl_cfg_s2sin;

local err_c2s, err_s2sin, err_s2sout;

function module.load(reload)

	local NULL = {};

	local modhost = module.host;

	local parent = modhost:match("%.(.*)$");

	local parent_ssl = rawgetopt(parent,  "ssl") or NULL;

	local host_ssl   = rawgetopt(modhost, "ssl") or parent_ssl;

	local global_c2s = rawgetopt("*",     "c2s_ssl") or NULL;

	local parent_c2s = rawgetopt(parent,  "c2s_ssl") or NULL;

	local host_c2s   = rawgetopt(modhost, "c2s_ssl") or parent_c2s;

	local global_s2s = rawgetopt("*",     "s2s_ssl") or NULL;

	local parent_s2s = rawgetopt(parent,  "s2s_ssl") or NULL;

	local host_s2s   = rawgetopt(modhost, "s2s_ssl") or parent_s2s;

	module:log("debug", "Creating context for c2s");

	local request_client_certs = { verify = { "peer", "client_once", }; };

	local xmpp_alpn = { alpn = "xmpp-server" };

	ssl_ctx_c2s, err_c2s, ssl_cfg_c2s = create_context(host.host, "server", host_c2s, host_ssl, global_c2s); -- for incoming client connections

	if not ssl_ctx_c2s then module:log("error", "Error creating context for c2s: %s", err_c2s); end

	module:log("debug", "Creating context for s2sout");

	-- for outgoing server connections

	ssl_ctx_s2sout, err_s2sout, ssl_cfg_s2sout = create_context(host.host, "client", host_s2s, host_ssl, global_s2s, request_client_certs, xmpp_alpn);

	if not ssl_ctx_s2sout then module:log("error", "Error creating contexts for s2sout: %s", err_s2sout); end

	module:log("debug", "Creating context for s2sin");

	-- for incoming server connections

	ssl_ctx_s2sin, err_s2sin, ssl_cfg_s2sin = create_context(host.host, "server", host_s2s, host_ssl, global_s2s, request_client_certs);

	if not ssl_ctx_s2sin then module:log("error", "Error creating contexts for s2sin: %s", err_s2sin); end

	if reload then

		module:log("info", "Certificates reloaded");

	else

		module:log("info", "Certificates loaded");

	end

end

module:hook_global("config-reloaded", module.load);

local function can_do_tls(session)

	if session.conn and not session.conn.starttls then

		if not session.secure then

			session.log("debug", "Underlying connection does not support STARTTLS");

		end

		return false;

	elseif session.ssl_ctx ~= nil then

		return session.ssl_ctx;

	end

	if session.type == "c2s_unauthed" then

		if not ssl_ctx_c2s and c2s_require_encryption then

			session.log("error", "No TLS context available for c2s. Earlier error was: %s", err_c2s);

		end

		session.ssl_ctx = ssl_ctx_c2s;

		session.ssl_cfg = ssl_cfg_c2s;

	elseif session.type == "s2sin_unauthed" and allow_s2s_tls then

		if not ssl_ctx_s2sin and s2s_require_encryption then

			session.log("error", "No TLS context available for s2sin. Earlier error was: %s", err_s2sin);

		end

		session.ssl_ctx = ssl_ctx_s2sin;

		session.ssl_cfg = ssl_cfg_s2sin;

	elseif session.direction == "outgoing" and allow_s2s_tls then

		if not ssl_ctx_s2sout and s2s_require_encryption then

			session.log("error", "No TLS context available for s2sout. Earlier error was: %s", err_s2sout);

		end

		session.ssl_ctx = ssl_ctx_s2sout;

		session.ssl_cfg = ssl_cfg_s2sout;

	else

		session.log("debug", "Unknown session type, don't know which TLS context to use");

		return false;

	end

	if not session.ssl_ctx then

		session.log("debug", "Should be able to do TLS but no context available");

		return false;

	end

	return session.ssl_ctx;

end

module:hook("s2sout-created", function (event)

	-- Initialize TLS context for outgoing connections

	can_do_tls(event.session);

end);

-- Hook <starttls/>

module:hook("stanza/urn:ietf:params:xml:ns:xmpp-tls:starttls", function(event)

	local origin = event.origin;

	if can_do_tls(origin) then

		(origin.sends2s or origin.send)(starttls_proceed);

		if origin.destroyed then return end

		origin:reset_stream();

		origin.conn:starttls(origin.ssl_ctx);

		origin.log("debug", "TLS negotiation started for %s...", origin.type);

		origin.secure = false;

	else

		origin.log("warn", "Attempt to start TLS, but TLS is not available on this %s connection", origin.type);

		(origin.sends2s or origin.send)(starttls_failure);

		origin:close();

	end

	return true;

end);

-- Advertise stream feature

module:hook("stream-features", function(event)

	local origin, features = event.origin, event.features;

	if can_do_tls(origin) then

		features:add_child(c2s_feature);

	end

end);

module:hook("s2s-stream-features", function(event)

	local origin, features = event.origin, event.features;

	if can_do_tls(origin) then

		features:add_child(s2s_feature);

	end

end);

-- For s2sout connections, start TLS if we can

module:hook_tag("http://etherx.jabber.org/streams", "features", function (session, stanza)

	module:log("debug", "Received features element");

	if can_do_tls(session) then

		if stanza:get_child("starttls", xmlns_starttls) then

			module:log("debug", "%s is offering TLS, taking up the offer...", session.to_host);

		elseif s2s_require_encryption then

			module:log("debug", "%s is *not* offering TLS, trying anyways!", session.to_host);

		else

			module:log("debug", "%s is not offering TLS", session.to_host);

			return;

		end

		session.sends2s(starttls_initiate);

		return true;

	end

end, 500);

module:hook("s2sout-authenticate-legacy", function(event)

	local session = event.origin;

	if s2s_require_encryption and can_do_tls(session) then

		session.sends2s(starttls_initiate);

		return true;

	end

end, 200);

module:hook_tag(xmlns_starttls, "proceed", function (session, stanza) -- luacheck: ignore 212/stanza

	if session.type == "s2sout_unauthed" and can_do_tls(session) then

		module:log("debug", "Proceeding with TLS on s2sout...");

		session:reset_stream();

		session.conn:starttls(session.ssl_ctx);

		session.secure = false;

		return true;

	end

end);

module:hook_tag(xmlns_starttls, "failure", function (session, stanza) -- luacheck: ignore 212/stanza

	module:log("warn", "TLS negotiation with %s failed.", session.to_host);

	session:close(nil, "TLS negotiation failed");

	return false;

end);