plugins/mod_s2s/mod_s2s.lua

   1 -- Prosody IM
   2 -- Copyright (C) 2008-2010 Matthew Wild
   3 -- Copyright (C) 2008-2010 Waqas Hussain
   4 --
   5 -- This project is MIT/X11 licensed. Please see the
   6 -- COPYING file in the source package for more information.
   7 --
   8
   9 module:set_global();
  10
  11 local prosody = prosody;
  12 local hosts = prosody.hosts;
  13 local core_process_stanza = core_process_stanza;
  14
  15 local tostring, type = tostring, type;
  16 local t_insert = table.insert;
  17 local xpcall, traceback = xpcall, debug.traceback;
  18
  19 local add_task = require "util.timer".add_task;
  20 local st = require "util.stanza";
  21 local initialize_filters = require "util.filters".initialize;
  22 local nameprep = require "util.encodings".stringprep.nameprep;
  23 local new_xmpp_stream = require "util.xmppstream".new;
  24 local s2s_new_incoming = require "core.s2smanager".new_incoming;
  25 local s2s_new_outgoing = require "core.s2smanager".new_outgoing;
  26 local s2s_destroy_session = require "core.s2smanager".destroy_session;
  27 local s2s_mark_connected = require "core.s2smanager".mark_connected;
  28 local uuid_gen = require "util.uuid".generate;
  29 local cert_verify_identity = require "util.x509".verify_identity;
  30
  31 local s2sout = module:require("s2sout");
  32
  33 local connect_timeout = module:get_option_number("s2s_timeout", 60);
  34
  35 local sessions = module:shared("sessions");
  36
  37 local log = module._log;
  38
  39 --- Handle stanzas to remote domains
  40
  41 local bouncy_stanzas = { message = true, presence = true, iq = true };
  42 local function bounce_sendq(session, reason)
  43         local sendq = session.sendq;
  44         if not sendq then return; end
  45         session.log("info", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
  46         local dummy = {
  47                 type = "s2sin";
  48                 send = function(s)
  49                         (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", traceback());
  50                 end;
  51                 dummy = true;
  52         };
  53         for i, data in ipairs(sendq) do
  54                 local reply = data[2];
  55                 if reply and not(reply.attr.xmlns) and bouncy_stanzas[reply.name] then
  56                         reply.attr.type = "error";
  57                         reply:tag("error", {type = "cancel"})
  58                                 :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
  59                         if reason then
  60                                 reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"})
  61                                         :text("Server-to-server connection failed: "..reason):up();
  62                         end
  63                         core_process_stanza(dummy, reply);
  64                 end
  65                 sendq[i] = nil;
  66         end
  67         session.sendq = nil;
  68 end
  69
  70 -- Handles stanzas to existing s2s sessions
  71 function route_to_existing_session(event)
  72         local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
  73         if not hosts[from_host] then
  74                 log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host);
  75                 return false;
  76         end
  77         local host = hosts[from_host].s2sout[to_host];
  78         if host then
  79                 -- We have a connection to this host already
  80                 if host.type == "s2sout_unauthed" and (stanza.name ~= "db:verify" or not host.dialback_key) then
  81                         (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
  82
  83                         -- Queue stanza until we are able to send it
  84                         if host.sendq then t_insert(host.sendq, {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)});
  85                         else host.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} }; end
  86                         host.log("debug", "stanza [%s] queued ", stanza.name);
  87                         return true;
  88                 elseif host.type == "local" or host.type == "component" then
  89                         log("error", "Trying to send a stanza to ourselves??")
  90                         log("error", "Traceback: %s", traceback());
  91                         log("error", "Stanza: %s", tostring(stanza));
  92                         return false;
  93                 else
  94                         (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
  95                         -- FIXME
  96                         if host.from_host ~= from_host then
  97                                 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
  98                                 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
  99                         end
 100                         host.sends2s(stanza);
 101                         host.log("debug", "stanza sent over "..host.type);
 102                         return true;
 103                 end
 104         end
 105 end
 106
 107 -- Create a new outgoing session for a stanza
 108 function route_to_new_session(event)
 109         local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
 110         log("debug", "opening a new outgoing connection for this stanza");
 111         local host_session = s2s_new_outgoing(from_host, to_host);
 112
 113         -- Store in buffer
 114         host_session.bounce_sendq = bounce_sendq;
 115         host_session.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} };
 116         log("debug", "stanza [%s] queued until connection complete", tostring(stanza.name));
 117         s2sout.initiate_connection(host_session);
 118         if (not host_session.connecting) and (not host_session.conn) then
 119                 log("warn", "Connection to %s failed already, destroying session...", to_host);
 120                 s2s_destroy_session(host_session, "Connection failed");
 121                 return false;
 122         end
 123         return true;
 124 end
 125
 126 function module.add_host(module)
 127         if module:get_option_boolean("disallow_s2s", false) then
 128                 module:log("warn", "The 'disallow_s2s' config option is deprecated, please see http://prosody.im/doc/s2s#disabling");
 129                 return nil, "This host has disallow_s2s set";
 130         end
 131         module:hook("route/remote", route_to_existing_session, 200);
 132         module:hook("route/remote", route_to_new_session, 100);
 133 end
 134
 135 --- Helper to check that a session peer's certificate is valid
 136 local function check_cert_status(session)
 137         local conn = session.conn:socket()
 138         local cert
 139         if conn.getpeercertificate then
 140                 cert = conn:getpeercertificate()
 141         end
 142
 143         if cert then
 144                 local chain_valid, errors = conn:getpeerverification()
 145                 -- Is there any interest in printing out all/the number of errors here?
 146                 if not chain_valid then
 147                         (session.log or log)("debug", "certificate chain validation result: invalid");
 148                         for depth, t in ipairs(errors) do
 149                                 (session.log or log)("debug", "certificate error(s) at depth %d: %s", depth-1, table.concat(t, ", "))
 150                         end
 151                         session.cert_chain_status = "invalid";
 152                 else
 153                         (session.log or log)("debug", "certificate chain validation result: valid");
 154                         session.cert_chain_status = "valid";
 155
 156                         local host = session.direction == "incoming" and session.from_host or session.to_host
 157
 158                         -- We'll go ahead and verify the asserted identity if the
 159                         -- connecting server specified one.
 160                         if host then
 161                                 if cert_verify_identity(host, "xmpp-server", cert) then
 162                                         session.cert_identity_status = "valid"
 163                                 else
 164                                         session.cert_identity_status = "invalid"
 165                                 end
 166                         end
 167                 end
 168         end
 169 end
 170
 171 --- XMPP stream event handlers
 172
 173 local stream_callbacks = { default_ns = "jabber:server", handlestanza =  core_process_stanza };
 174
 175 local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";
 176
 177 function stream_callbacks.streamopened(session, attr)
 178         local send = session.sends2s;
 179
 180         session.version = tonumber(attr.version) or 0;
 181
 182         -- TODO: Rename session.secure to session.encrypted
 183         if session.secure == false then
 184                 session.secure = true;
 185         end
 186
 187         if session.direction == "incoming" then
 188                 -- Send a reply stream header
 189
 190                 -- Validate to/from
 191                 local to, from = nameprep(attr.to), nameprep(attr.from);
 192                 if not to and attr.to then -- COMPAT: Some servers do not reliably set 'to' (especially on stream restarts)
 193                         session:close({ condition = "improper-addressing", text = "Invalid 'to' address" });
 194                         return;
 195                 end
 196                 if not from and attr.from then -- COMPAT: Some servers do not reliably set 'from' (especially on stream restarts)
 197                         session:close({ condition = "improper-addressing", text = "Invalid 'from' address" });
 198                         return;
 199                 end
 200
 201                 -- Set session.[from/to]_host if they have not been set already and if
 202                 -- this session isn't already authenticated
 203                 if session.type == "s2sin_unauthed" and from and not session.from_host then
 204                         session.from_host = from;
 205                 elseif from ~= session.from_host then
 206                         session:close({ condition = "improper-addressing", text = "New stream 'from' attribute does not match original" });
 207                         return;
 208                 end
 209                 if session.type == "s2sin_unauthed" and to and not session.to_host then
 210                         session.to_host = to;
 211                 elseif to ~= session.to_host then
 212                         session:close({ condition = "improper-addressing", text = "New stream 'to' attribute does not match original" });
 213                         return;
 214                 end
 215
 216                 -- For convenience we'll put the sanitised values into these variables
 217                 to, from = session.to_host, session.from_host;
 218
 219                 session.streamid = uuid_gen();
 220                 (session.log or log)("debug", "Incoming s2s received %s", st.stanza("stream:stream", attr):top_tag());
 221                 if to then
 222                         if not hosts[to] then
 223                                 -- Attempting to connect to a host we don't serve
 224                                 session:close({
 225                                         condition = "host-unknown";
 226                                         text = "This host does not serve "..to
 227                                 });
 228                                 return;
 229                         elseif not hosts[to].modules.s2s then
 230                                 -- Attempting to connect to a host that disallows s2s
 231                                 session:close({
 232                                         condition = "policy-violation";
 233                                         text = "Server-to-server communication is disabled for this host";
 234                                 });
 235                                 return;
 236                         end
 237                 end
 238
 239                 if session.secure and not session.cert_chain_status then check_cert_status(session); end
 240
 241                 send("<?xml version='1.0'?>");
 242                 send(st.stanza("stream:stream", { xmlns='jabber:server', ["xmlns:db"]='jabber:server:dialback',
 243                                 ["xmlns:stream"]='http://etherx.jabber.org/streams', id=session.streamid, from=to, to=from, version=(session.version > 0 and "1.0" or nil) }):top_tag());
 244                 if session.version >= 1.0 then
 245                         local features = st.stanza("stream:features");
 246
 247                         if to then
 248                                 hosts[to].events.fire_event("s2s-stream-features", { origin = session, features = features });
 249                         else
 250                                 (session.log or log)("warn", "No 'to' on stream header from %s means we can't offer any features", from or "unknown host");
 251                         end
 252
 253                         log("debug", "Sending stream features: %s", tostring(features));
 254                         send(features);
 255                 end
 256         elseif session.direction == "outgoing" then
 257                 -- If we are just using the connection for verifying dialback keys, we won't try and auth it
 258                 if not attr.id then error("stream response did not give us a streamid!!!"); end
 259                 session.streamid = attr.id;
 260
 261                 if session.secure and not session.cert_chain_status then check_cert_status(session); end
 262
 263                 -- Send unauthed buffer
 264                 -- (stanzas which are fine to send before dialback)
 265                 -- Note that this is *not* the stanza queue (which
 266                 -- we can only send if auth succeeds) :)
 267                 local send_buffer = session.send_buffer;
 268                 if send_buffer and #send_buffer > 0 then
 269                         log("debug", "Sending s2s send_buffer now...");
 270                         for i, data in ipairs(send_buffer) do
 271                                 session.sends2s(tostring(data));
 272                                 send_buffer[i] = nil;
 273                         end
 274                 end
 275                 session.send_buffer = nil;
 276
 277                 -- If server is pre-1.0, don't wait for features, just do dialback
 278                 if session.version < 1.0 then
 279                         if not session.dialback_verifying then
 280                                 hosts[session.from_host].events.fire_event("s2s-authenticate-legacy", { origin = session });
 281                         else
 282                                 s2s_mark_connected(session);
 283                         end
 284                 end
 285         end
 286         session.notopen = nil;
 287 end
 288
 289 function stream_callbacks.streamclosed(session)
 290         (session.log or log)("debug", "Received </stream:stream>");
 291         session:close();
 292 end
 293
 294 function stream_callbacks.streamdisconnected(session, err)
 295         if err and err ~= "closed" and session.direction == "outgoing" and session.notopen then
 296                 (session.log or log)("debug", "s2s connection attempt failed: %s", err);
 297                 if s2sout.attempt_connection(session, err) then
 298                         (session.log or log)("debug", "...so we're going to try another target");
 299                         return true; -- Session lives for now
 300                 end
 301         end
 302         (session.log or log)("info", "s2s disconnected: %s->%s (%s)", tostring(session.from_host), tostring(session.to_host), tostring(err or "closed"));
 303         s2s_destroy_session(session, err);
 304 end
 305
 306 function stream_callbacks.error(session, error, data)
 307         if error == "no-stream" then
 308                 session:close("invalid-namespace");
 309         elseif error == "parse-error" then
 310                 session.log("debug", "Server-to-server XML parse error: %s", tostring(error));
 311                 session:close("not-well-formed");
 312         elseif error == "stream-error" then
 313                 local condition, text = "undefined-condition";
 314                 for child in data:children() do
 315                         if child.attr.xmlns == xmlns_xmpp_streams then
 316                                 if child.name ~= "text" then
 317                                         condition = child.name;
 318                                 else
 319                                         text = child:get_text();
 320                                 end
 321                                 if condition ~= "undefined-condition" and text then
 322                                         break;
 323                                 end
 324                         end
 325                 end
 326                 text = condition .. (text and (" ("..text..")") or "");
 327                 session.log("info", "Session closed by remote with error: %s", text);
 328                 session:close(nil, text);
 329         end
 330 end
 331
 332 local function handleerr(err) log("error", "Traceback[s2s]: %s: %s", tostring(err), traceback()); end
 333 function stream_callbacks.handlestanza(session, stanza)
 334         if stanza.attr.xmlns == "jabber:client" then --COMPAT: Prosody pre-0.6.2 may send jabber:client
 335                 stanza.attr.xmlns = nil;
 336         end
 337         stanza = session.filter("stanzas/in", stanza);
 338         if stanza then
 339                 return xpcall(function () return core_process_stanza(session, stanza) end, handleerr);
 340         end
 341 end
 342
 343 local listener = {};
 344
 345 --- Session methods
 346 local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
 347 local default_stream_attr = { ["xmlns:stream"] = "http://etherx.jabber.org/streams", xmlns = stream_callbacks.default_ns, version = "1.0", id = "" };
 348 local function session_close(session, reason, remote_reason)
 349         local log = session.log or log;
 350         if session.conn then
 351                 if session.notopen then
 352                         session.sends2s("<?xml version='1.0'?>");
 353                         session.sends2s(st.stanza("stream:stream", default_stream_attr):top_tag());
 354                 end
 355                 if reason then
 356                         if type(reason) == "string" then -- assume stream error
 357                                 log("info", "Disconnecting %s[%s], <stream:error> is: %s", session.host or "(unknown host)", session.type, reason);
 358                                 session.sends2s(st.stanza("stream:error"):tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' }));
 359                         elseif type(reason) == "table" then
 360                                 if reason.condition then
 361                                         local stanza = st.stanza("stream:error"):tag(reason.condition, stream_xmlns_attr):up();
 362                                         if reason.text then
 363                                                 stanza:tag("text", stream_xmlns_attr):text(reason.text):up();
 364                                         end
 365                                         if reason.extra then
 366                                                 stanza:add_child(reason.extra);
 367                                         end
 368                                         log("info", "Disconnecting %s[%s], <stream:error> is: %s", session.host or "(unknown host)", session.type, tostring(stanza));
 369                                         session.sends2s(stanza);
 370                                 elseif reason.name then -- a stanza
 371                                         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));
 372                                         session.sends2s(reason);
 373                                 end
 374                         end
 375                 end
 376                 session.sends2s("</stream:stream>");
 377                 if session.notopen or not session.conn:close() then
 378                         session.conn:close(true); -- Force FIXME: timer?
 379                 end
 380                 session.conn:close();
 381                 listener.ondisconnect(session.conn, remote_reason or (reason and (reason.text or reason.condition)) or reason or "stream closed");
 382         end
 383 end
 384
 385 -- Session initialization logic shared by incoming and outgoing
 386 local function initialize_session(session)
 387         local stream = new_xmpp_stream(session, stream_callbacks);
 388         session.stream = stream;
 389
 390         session.notopen = true;
 391
 392         function session.reset_stream()
 393                 session.notopen = true;
 394                 session.stream:reset();
 395         end
 396
 397         local filter = session.filter;
 398         function session.data(data)
 399                 data = filter("bytes/in", data);
 400                 if data then
 401                         local ok, err = stream:feed(data);
 402                         if ok then return; end
 403                         (session.log or log)("warn", "Received invalid XML: %s", data);
 404                         (session.log or log)("warn", "Problem was: %s", err);
 405                         session:close("not-well-formed");
 406                 end
 407         end
 408
 409         session.close = session_close;
 410
 411         local handlestanza = stream_callbacks.handlestanza;
 412         function session.dispatch_stanza(session, stanza)
 413                 return handlestanza(session, stanza);
 414         end
 415
 416         local conn = session.conn;
 417         add_task(connect_timeout, function ()
 418                 if session.conn ~= conn or session.connecting
 419                 or session.type == "s2sin" or session.type == "s2sout" then
 420                         return; -- Ok, we're connect[ed|ing]
 421                 end
 422                 -- Not connected, need to close session and clean up
 423                 (session.log or log)("debug", "Destroying incomplete session %s->%s due to inactivity",
 424                 session.from_host or "(unknown)", session.to_host or "(unknown)");
 425                 session:close("connection-timeout");
 426         end);
 427 end
 428
 429 function listener.onconnect(conn)
 430         local session = sessions[conn];
 431         if not session then -- New incoming connection
 432                 session = s2s_new_incoming(conn);
 433                 sessions[conn] = session;
 434                 session.log("debug", "Incoming s2s connection");
 435
 436                 local filter = initialize_filters(session);
 437                 local w = conn.write;
 438                 session.sends2s = function (t)
 439                         log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^([^>]*>?)"));
 440                         if t.name then
 441                                 t = filter("stanzas/out", t);
 442                         end
 443                         if t then
 444                                 t = filter("bytes/out", tostring(t));
 445                                 if t then
 446                                         return w(conn, t);
 447                                 end
 448                         end
 449                 end
 450
 451                 initialize_session(session);
 452         else -- Outgoing session connected
 453                 session:open_stream(session.from_host, session.to_host);
 454         end
 455 end
 456
 457 function listener.onincoming(conn, data)
 458         local session = sessions[conn];
 459         if session then
 460                 session.data(data);
 461         end
 462 end
 463
 464 function listener.onstatus(conn, status)
 465         if status == "ssl-handshake-complete" then
 466                 local session = sessions[conn];
 467                 if session and session.direction == "outgoing" then
 468                         session.log("debug", "Sending stream header...");
 469                         session:open_stream(session.from_host, session.to_host);
 470                 end
 471         end
 472 end
 473
 474 function listener.ondisconnect(conn, err)
 475         local session = sessions[conn];
 476         if session then
 477                 if stream_callbacks.streamdisconnected(session, err) then
 478                         return; -- Connection lives, for now
 479                 end
 480         end
 481         sessions[conn] = nil;
 482 end
 483
 484 function listener.register_outgoing(conn, session)
 485         session.direction = "outgoing";
 486         sessions[conn] = session;
 487         initialize_session(session);
 488 end
 489
 490 s2sout.set_listener(listener);
 491
 492 module:add_item("net-provider", {
 493         name = "s2s";
 494         listener = listener;
 495         default_port = 5269;
 496         encryption = "starttls";
 497         multiplex = {
 498                 pattern = "^<.*:stream.*%sxmlns%s*=%s*(['\"])jabber:server%1.*>";
 499         };
 500 });
 501