Diff

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/plugins/mod_s2s/mod_s2s.lua	Fri May 04 00:05:15 2012 +0100
@@ -0,0 +1,486 @@
+-- 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.
+--
+
+module:set_global();
+
+local prosody = prosody;
+local hosts = prosody.hosts;
+local core_process_stanza = core_process_stanza;
+
+local tostring, type = tostring, type;
+local t_insert = table.insert;
+local xpcall, traceback = xpcall, debug.traceback;
+
+local add_task = require "util.timer".add_task;
+local st = require "util.stanza";
+local initialize_filters = require "util.filters".initialize;
+local nameprep = require "util.encodings".stringprep.nameprep;
+local new_xmpp_stream = require "util.xmppstream".new;
+local s2s_new_incoming = require "core.s2smanager".new_incoming;
+local s2s_new_outgoing = require "core.s2smanager".new_outgoing;
+local s2s_destroy_session = require "core.s2smanager".destroy_session;
+local s2s_mark_connected = require "core.s2smanager".mark_connected;
+local uuid_gen = require "util.uuid".generate;
+local cert_verify_identity = require "util.x509".verify_identity;
+
+local s2sout = module:require("s2sout");
+
+local connect_timeout = module:get_option_number("s2s_timeout", 60);
+
+local sessions = module:shared("sessions");
+
+local log = module._log;
+
+--- Handle stanzas to remote domains
+
+local bouncy_stanzas = { message = true, presence = true, iq = true };
+local function bounce_sendq(session, reason)
+	local sendq = session.sendq;
+	if not sendq then return; end
+	session.log("info", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
+	local dummy = {
+		type = "s2sin";
+		send = function(s)
+			(session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", traceback());
+		end;
+		dummy = true;
+	};
+	for i, data in ipairs(sendq) do
+		local reply = data[2];
+		if reply and not(reply.attr.xmlns) and bouncy_stanzas[reply.name] then
+			reply.attr.type = "error";
+			reply:tag("error", {type = "cancel"})
+				:tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
+			if reason then
+				reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"})
+					:text("Server-to-server connection failed: "..reason):up();
+			end
+			core_process_stanza(dummy, reply);
+		end
+		sendq[i] = nil;
+	end
+	session.sendq = nil;
+end
+
+module:hook("route/remote", function (event)
+	local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
+	if not hosts[from_host] then
+		log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host);
+		return false;
+	end
+	local host = hosts[from_host].s2sout[to_host];
+	if host then
+		-- We have a connection to this host already
+		if host.type == "s2sout_unauthed" and (stanza.name ~= "db:verify" or not host.dialback_key) then
+			(host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
+
+			-- Queue stanza until we are able to send it
+			if host.sendq then t_insert(host.sendq, {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)});
+			else host.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} }; end
+			host.log("debug", "stanza [%s] queued ", stanza.name);
+			return true;
+		elseif host.type == "local" or host.type == "component" then
+			log("error", "Trying to send a stanza to ourselves??")
+			log("error", "Traceback: %s", traceback());
+			log("error", "Stanza: %s", tostring(stanza));
+			return false;
+		else
+			(host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
+			-- FIXME
+			if host.from_host ~= from_host then
+				log("error", "WARNING! This might, possibly, be a bug, but it might not...");
+				log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
+			end
+			host.sends2s(stanza);
+			host.log("debug", "stanza sent over "..host.type);
+			return true;
+		end
+	end
+end, 200);
+
+module:hook("route/remote", function (event)
+	local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
+	log("debug", "opening a new outgoing connection for this stanza");
+	local host_session = s2s_new_outgoing(from_host, to_host);
+
+	-- Store in buffer
+	host_session.bounce_sendq = bounce_sendq;
+	host_session.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} };
+	log("debug", "stanza [%s] queued until connection complete", tostring(stanza.name));
+	s2sout.initiate_connection(host_session);
+	if (not host_session.connecting) and (not host_session.conn) then
+		log("warn", "Connection to %s failed already, destroying session...", to_host);
+		s2s_destroy_session(host_session, "Connection failed");
+		return false;
+	end
+	return true;
+end, 100);
+
+--- Helper to check that a session peer's certificate is valid
+local function check_cert_status(session)
+	local conn = session.conn:socket()
+	local cert
+	if conn.getpeercertificate then
+		cert = conn:getpeercertificate()
+	end
+
+	if cert then
+		local chain_valid, errors = conn:getpeerverification()
+		-- Is there any interest in printing out all/the number of errors here?
+		if not chain_valid then
+			(session.log or log)("debug", "certificate chain validation result: invalid");
+			for depth, t in ipairs(errors) do
+				(session.log or log)("debug", "certificate error(s) at depth %d: %s", depth-1, table.concat(t, ", "))
+			end
+			session.cert_chain_status = "invalid";
+		else
+			(session.log or log)("debug", "certificate chain validation result: valid");
+			session.cert_chain_status = "valid";
+
+			local host = session.direction == "incoming" and session.from_host or session.to_host
+
+			-- We'll go ahead and verify the asserted identity if the
+			-- connecting server specified one.
+			if host then
+				if cert_verify_identity(host, "xmpp-server", cert) then
+					session.cert_identity_status = "valid"
+				else
+					session.cert_identity_status = "invalid"
+				end
+			end
+		end
+	end
+end
+
+--- XMPP stream event handlers
+
+local stream_callbacks = { default_ns = "jabber:server", handlestanza =  core_process_stanza };
+
+local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";
+
+function stream_callbacks.streamopened(session, attr)
+	local send = session.sends2s;
+	
+	-- TODO: #29: SASL/TLS on s2s streams
+	session.version = tonumber(attr.version) or 0;
+	
+	-- TODO: Rename session.secure to session.encrypted
+	if session.secure == false then
+		session.secure = true;
+	end
+
+	if session.direction == "incoming" then
+		-- Send a reply stream header
+		
+		-- Validate to/from
+		local to, from = nameprep(attr.to), nameprep(attr.from);
+		if not to and attr.to then -- COMPAT: Some servers do not reliably set 'to' (especially on stream restarts)
+			session:close({ condition = "improper-addressing", text = "Invalid 'to' address" });
+			return;
+		end
+		if not from and attr.from then -- COMPAT: Some servers do not reliably set 'from' (especially on stream restarts)
+			session:close({ condition = "improper-addressing", text = "Invalid 'from' address" });
+			return;
+		end
+		
+		-- Set session.[from/to]_host if they have not been set already and if
+		-- this session isn't already authenticated
+		if session.type == "s2sin_unauthed" and from and not session.from_host then
+			session.from_host = from;
+		elseif from ~= session.from_host then
+			session:close({ condition = "improper-addressing", text = "New stream 'from' attribute does not match original" });
+			return;
+		end
+		if session.type == "s2sin_unauthed" and to and not session.to_host then
+			session.to_host = to;
+		elseif to ~= session.to_host then
+			session:close({ condition = "improper-addressing", text = "New stream 'to' attribute does not match original" });
+			return;
+		end
+		
+		session.streamid = uuid_gen();
+		(session.log or log)("debug", "Incoming s2s received %s", st.stanza("stream:stream", attr):top_tag());
+		if session.to_host then
+			if not hosts[session.to_host] then
+				-- Attempting to connect to a host we don't serve
+				session:close({
+					condition = "host-unknown";
+					text = "This host does not serve "..session.to_host
+				});
+				return;
+			elseif hosts[session.to_host].disallow_s2s then
+				-- Attempting to connect to a host that disallows s2s
+				session:close({
+					condition = "policy-violation";
+					text = "Server-to-server communication is not allowed to this host";
+				});
+				return;
+			end
+		end
+
+		if session.secure and not session.cert_chain_status then check_cert_status(session); end
+
+		send("<?xml version='1.0'?>");
+		send(st.stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
+				["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=session.to_host, to=session.from_host, version=(session.version > 0 and "1.0" or nil) }):top_tag());
+		if session.version >= 1.0 then
+			local features = st.stanza("stream:features");
+			
+			if session.to_host then
+				hosts[session.to_host].events.fire_event("s2s-stream-features", { origin = session, features = features });
+			else
+				(session.log or log)("warn", "No 'to' on stream header from %s means we can't offer any features", session.from_host or "unknown host");
+			end
+			
+			log("debug", "Sending stream features: %s", tostring(features));
+			send(features);
+		end
+	elseif session.direction == "outgoing" then
+		-- If we are just using the connection for verifying dialback keys, we won't try and auth it
+		if not attr.id then error("stream response did not give us a streamid!!!"); end
+		session.streamid = attr.id;
+
+		if session.secure and not session.cert_chain_status then check_cert_status(session); end
+
+		-- Send unauthed buffer
+		-- (stanzas which are fine to send before dialback)
+		-- Note that this is *not* the stanza queue (which
+		-- we can only send if auth succeeds) :)
+		local send_buffer = session.send_buffer;
+		if send_buffer and #send_buffer > 0 then
+			log("debug", "Sending s2s send_buffer now...");
+			for i, data in ipairs(send_buffer) do
+				session.sends2s(tostring(data));
+				send_buffer[i] = nil;
+			end
+		end
+		session.send_buffer = nil;
+	
+		-- If server is pre-1.0, don't wait for features, just do dialback
+		if session.version < 1.0 then
+			if not session.dialback_verifying then
+				hosts[session.from_host].events.fire_event("s2s-authenticate-legacy", { origin = session });
+			else
+				s2s_mark_connected(session);
+			end
+		end
+	end
+	session.notopen = nil;
+	session.send = function(stanza) prosody.events.fire_event("route/remote", { from_host = session.to_host, to_host = session.from_host, stanza = stanza}) end;
+end
+
+function stream_callbacks.streamclosed(session)
+	(session.log or log)("debug", "Received </stream:stream>");
+	session:close();
+end
+
+function stream_callbacks.streamdisconnected(session, err)
+	if err and err ~= "closed" and session.direction == "outgoing" then
+		(session.log or log)("debug", "s2s connection attempt failed: %s", err);
+		if s2sout.attempt_connection(session, err) then
+			(session.log or log)("debug", "...so we're going to try another target");
+			return true; -- Session lives for now
+		end
+	end
+	(session.log or log)("info", "s2s disconnected: %s->%s (%s)", tostring(session.from_host), tostring(session.to_host), tostring(err or "closed"));
+	s2s_destroy_session(session, err);
+end
+
+function stream_callbacks.error(session, error, data)
+	if error == "no-stream" then
+		session:close("invalid-namespace");
+	elseif error == "parse-error" then
+		session.log("debug", "Server-to-server XML parse error: %s", tostring(error));
+		session:close("not-well-formed");
+	elseif error == "stream-error" then
+		local condition, text = "undefined-condition";
+		for child in data:children() do
+			if child.attr.xmlns == xmlns_xmpp_streams then
+				if child.name ~= "text" then
+					condition = child.name;
+				else
+					text = child:get_text();
+				end
+				if condition ~= "undefined-condition" and text then
+					break;
+				end
+			end
+		end
+		text = condition .. (text and (" ("..text..")") or "");
+		session.log("info", "Session closed by remote with error: %s", text);
+		session:close(nil, text);
+	end
+end
+
+local function handleerr(err) log("error", "Traceback[s2s]: %s: %s", tostring(err), traceback()); end
+function stream_callbacks.handlestanza(session, stanza)
+	if stanza.attr.xmlns == "jabber:client" then --COMPAT: Prosody pre-0.6.2 may send jabber:client
+		stanza.attr.xmlns = nil;
+	end
+	stanza = session.filter("stanzas/in", stanza);
+	if stanza then
+		return xpcall(function () return core_process_stanza(session, stanza) end, handleerr);
+	end
+end
+
+local listener = {};
+
+--- Session methods
+local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
+local default_stream_attr = { ["xmlns:stream"] = "http://etherx.jabber.org/streams", xmlns = stream_callbacks.default_ns, version = "1.0", id = "" };
+local function session_close(session, reason, remote_reason)
+	local log = session.log or log;
+	if session.conn then
+		if session.notopen then
+			session.sends2s("<?xml version='1.0'?>");
+			session.sends2s(st.stanza("stream:stream", default_stream_attr):top_tag());
+		end
+		if reason then
+			if type(reason) == "string" then -- assume stream error
+				log("info", "Disconnecting %s[%s], <stream:error> is: %s", session.host or "(unknown host)", session.type, reason);
+				session.sends2s(st.stanza("stream:error"):tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' }));
+			elseif type(reason) == "table" then
+				if reason.condition then
+					local stanza = st.stanza("stream:error"):tag(reason.condition, stream_xmlns_attr):up();
+					if reason.text then
+						stanza:tag("text", stream_xmlns_attr):text(reason.text):up();
+					end
+					if reason.extra then
+						stanza:add_child(reason.extra);
+					end
+					log("info", "Disconnecting %s[%s], <stream:error> is: %s", session.host or "(unknown host)", session.type, tostring(stanza));
+					session.sends2s(stanza);
+				elseif reason.name then -- a stanza
+					log("info", "Disconnecting %s->%s[%s], <stream:error> is: %s", session.from_host or "(unknown host)", session.to_host or "(unknown host)", session.type, tostring(reason));
+					session.sends2s(reason);
+				end
+			end
+		end
+		session.sends2s("</stream:stream>");
+		if session.notopen or not session.conn:close() then
+			session.conn:close(true); -- Force FIXME: timer?
+		end
+		session.conn:close();
+		listener.ondisconnect(session.conn, remote_reason or (reason and (reason.text or reason.condition)) or reason or "stream closed");
+	end
+end
+
+-- Session initialization logic shared by incoming and outgoing
+local function initialize_session(session)
+	local stream = new_xmpp_stream(session, stream_callbacks);
+	session.stream = stream;
+	
+	session.notopen = true;
+		
+	function session.reset_stream()
+		session.notopen = true;
+		session.stream:reset();
+	end
+	
+	local filter = session.filter;
+	function session.data(data)
+		data = filter("bytes/in", data);
+		if data then
+			local ok, err = stream:feed(data);
+			if ok then return; end
+			(session.log or log)("warn", "Received invalid XML: %s", data);
+			(session.log or log)("warn", "Problem was: %s", err);
+			session:close("not-well-formed");
+		end
+	end
+
+	session.close = session_close;
+
+	local handlestanza = stream_callbacks.handlestanza;
+	function session.dispatch_stanza(session, stanza)
+		return handlestanza(session, stanza);
+	end
+
+	local conn = session.conn;
+	add_task(connect_timeout, function ()
+		if session.conn ~= conn or session.connecting
+		or session.type == "s2sin" or session.type == "s2sout" then
+			return; -- Ok, we're connect[ed|ing]
+		end
+		-- Not connected, need to close session and clean up
+		(session.log or log)("debug", "Destroying incomplete session %s->%s due to inactivity",
+		session.from_host or "(unknown)", session.to_host or "(unknown)");
+		session:close("connection-timeout");
+	end);
+end
+
+function listener.onconnect(conn)
+	if not sessions[conn] then -- May be an existing outgoing session
+		local session = s2s_new_incoming(conn);
+		sessions[conn] = session;
+		session.log("debug", "Incoming s2s connection");
+
+		local filter = initialize_filters(session);
+		local w = conn.write;
+		session.sends2s = function (t)
+			log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^([^>]*>?)"));
+			if t.name then
+				t = filter("stanzas/out", t);
+			end
+			if t then
+				t = filter("bytes/out", tostring(t));
+				if t then
+					return w(conn, t);
+				end
+			end
+		end
+	
+		initialize_session(session);
+	end
+end
+
+function listener.onincoming(conn, data)
+	local session = sessions[conn];
+	if session then
+		session.data(data);
+	end
+end
+	
+function listener.onstatus(conn, status)
+	if status == "ssl-handshake-complete" then
+		local session = sessions[conn];
+		if session and session.direction == "outgoing" then
+			session.log("debug", "Sending stream header...");
+			session:open_stream(session.from_host, session.to_host);
+		end
+	end
+end
+
+function listener.ondisconnect(conn, err)
+	local session = sessions[conn];
+	if session then
+		if stream_callbacks.streamdisconnected(session, err) then
+			return; -- Connection lives, for now
+		end
+	end
+	sessions[conn] = nil;
+end
+
+function listener.register_outgoing(conn, session)
+	session.direction = "outgoing";
+	sessions[conn] = session;
+	initialize_session(session);
+end
+
+s2sout.set_listener(listener);
+
+module:add_item("net-provider", {
+	name = "s2s";
+	listener = listener;
+	default_port = 5269;
+	encryption = "starttls";
+	multiplex = {
+		pattern = "^<.*:stream.*%sxmlns%s*=%s*(['\"])jabber:server%1.*>";
+	};
+});
+