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 = prosody.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", 90);
  34 local stream_close_timeout = module:get_option_number("s2s_close_timeout", 5);
  35
  36 local sessions = module:shared("sessions");
  37
  38 local log = module._log;
  39
  40 --- Handle stanzas to remote domains
  41
  42 local bouncy_stanzas = { message = true, presence = true, iq = true };
  43 local function bounce_sendq(session, reason)
  44         local sendq = session.sendq;
  45         if not sendq then return; end
  46         session.log("info", "sending error replies for "..#sendq.." queued stanzas because of failed outgoing connection to "..tostring(session.to_host));
  47         local dummy = {
  48                 type = "s2sin";
  49                 send = function(s)
  50                         (session.log or log)("error", "Replying to to an s2s error reply, please report this! Traceback: %s", traceback());
  51                 end;
  52                 dummy = true;
  53         };
  54         for i, data in ipairs(sendq) do
  55                 local reply = data[2];
  56                 if reply and not(reply.attr.xmlns) and bouncy_stanzas[reply.name] then
  57                         reply.attr.type = "error";
  58                         reply:tag("error", {type = "cancel"})
  59                                 :tag("remote-server-not-found", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"}):up();
  60                         if reason then
  61                                 reply:tag("text", {xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas"})
  62                                         :text("Server-to-server connection failed: "..reason):up();
  63                         end
  64                         core_process_stanza(dummy, reply);
  65                 end
  66                 sendq[i] = nil;
  67         end
  68         session.sendq = nil;
  69 end
  70
  71 -- Handles stanzas to existing s2s sessions
  72 function route_to_existing_session(event)
  73         local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
  74         if not hosts[from_host] then
  75                 log("warn", "Attempt to send stanza from %s - a host we don't serve", from_host);
  76                 return false;
  77         end
  78         local host = hosts[from_host].s2sout[to_host];
  79         if host then
  80                 -- We have a connection to this host already
  81                 if host.type == "s2sout_unauthed" and (stanza.name ~= "db:verify" or not host.dialback_key) then
  82                         (host.log or log)("debug", "trying to send over unauthed s2sout to "..to_host);
  83
  84                         -- Queue stanza until we are able to send it
  85                         if host.sendq then t_insert(host.sendq, {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)});
  86                         else host.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} }; end
  87                         host.log("debug", "stanza [%s] queued ", stanza.name);
  88                         return true;
  89                 elseif host.type == "local" or host.type == "component" then
  90                         log("error", "Trying to send a stanza to ourselves??")
  91                         log("error", "Traceback: %s", traceback());
  92                         log("error", "Stanza: %s", tostring(stanza));
  93                         return false;
  94                 else
  95                         (host.log or log)("debug", "going to send stanza to "..to_host.." from "..from_host);
  96                         -- FIXME
  97                         if host.from_host ~= from_host then
  98                                 log("error", "WARNING! This might, possibly, be a bug, but it might not...");
  99                                 log("error", "We are going to send from %s instead of %s", tostring(host.from_host), tostring(from_host));
 100                         end
 101                         if host.sends2s(stanza) then
 102                                 host.log("debug", "stanza sent over %s", host.type);
 103                                 return true;
 104                         end
 105                 end
 106         end
 107 end
 108
 109 -- Create a new outgoing session for a stanza
 110 function route_to_new_session(event)
 111         local from_host, to_host, stanza = event.from_host, event.to_host, event.stanza;
 112         log("debug", "opening a new outgoing connection for this stanza");
 113         local host_session = s2s_new_outgoing(from_host, to_host);
 114
 115         -- Store in buffer
 116         host_session.bounce_sendq = bounce_sendq;
 117         host_session.sendq = { {tostring(stanza), stanza.attr.type ~= "error" and stanza.attr.type ~= "result" and st.reply(stanza)} };
 118         log("debug", "stanza [%s] queued until connection complete", tostring(stanza.name));
 119         s2sout.initiate_connection(host_session);
 120         if (not host_session.connecting) and (not host_session.conn) then
 121                 log("warn", "Connection to %s failed already, destroying session...", to_host);
 122                 s2s_destroy_session(host_session, "Connection failed");
 123                 return false;
 124         end
 125         return true;
 126 end
 127
 128 function module.add_host(module)
 129         if module:get_option_boolean("disallow_s2s", false) then
 130                 module:log("warn", "The 'disallow_s2s' config option is deprecated, please see http://prosody.im/doc/s2s#disabling");
 131                 return nil, "This host has disallow_s2s set";
 132         end
 133         module:hook("route/remote", route_to_existing_session, 200);
 134         module:hook("route/remote", route_to_new_session, 100);
 135 end
 136
 137 --- Helper to check that a session peer's certificate is valid
 138 local function check_cert_status(session)
 139         local host = session.direction == "incoming" and session.from_host or session.to_host
 140         local conn = session.conn:socket()
 141         local cert
 142         if conn.getpeercertificate then
 143                 cert = conn:getpeercertificate()
 144         end
 145
 146         if cert then
 147                 local chain_valid, errors = conn:getpeerverification()
 148                 -- Is there any interest in printing out all/the number of errors here?
 149                 if not chain_valid then
 150                         (session.log or log)("debug", "certificate chain validation result: invalid");
 151                         for depth, t in ipairs(errors) do
 152                                 (session.log or log)("debug", "certificate error(s) at depth %d: %s", depth-1, table.concat(t, ", "))
 153                         end
 154                         session.cert_chain_status = "invalid";
 155                 else
 156                         (session.log or log)("debug", "certificate chain validation result: valid");
 157                         session.cert_chain_status = "valid";
 158
 159                         -- We'll go ahead and verify the asserted identity if the
 160                         -- connecting server specified one.
 161                         if host then
 162                                 if cert_verify_identity(host, "xmpp-server", cert) then
 163                                         session.cert_identity_status = "valid"
 164                                 else
 165                                         session.cert_identity_status = "invalid"
 166                                 end
 167                         end
 168                 end
 169         end
 170         module:fire_event("s2s-check-certificate", { host = host, session = session, cert = cert });
 171 end
 172
 173 --- XMPP stream event handlers
 174
 175 local stream_callbacks = { default_ns = "jabber:server", handlestanza =  core_process_stanza };
 176
 177 local xmlns_xmpp_streams = "urn:ietf:params:xml:ns:xmpp-streams";
 178
 179 function stream_callbacks.streamopened(session, attr)
 180         local send = session.sends2s;
 181
 182         session.version = tonumber(attr.version) or 0;
 183
 184         -- TODO: Rename session.secure to session.encrypted
 185         if session.secure == false then
 186                 session.secure = true;
 187
 188                 -- Check if TLS compression is used
 189                 local sock = session.conn:socket();
 190                 if sock.info then
 191                         session.compressed = sock:info"compression";
 192                 elseif sock.compression then
 193                         session.compressed = sock:compression(); --COMPAT mw/luasec-hg
 194                 end
 195         end
 196
 197         if session.direction == "incoming" then
 198                 -- Send a reply stream header
 199
 200                 -- Validate to/from
 201                 local to, from = nameprep(attr.to), nameprep(attr.from);
 202                 if not to and attr.to then -- COMPAT: Some servers do not reliably set 'to' (especially on stream restarts)
 203                         session:close({ condition = "improper-addressing", text = "Invalid 'to' address" });
 204                         return;
 205                 end
 206                 if not from and attr.from then -- COMPAT: Some servers do not reliably set 'from' (especially on stream restarts)
 207                         session:close({ condition = "improper-addressing", text = "Invalid 'from' address" });
 208                         return;
 209                 end
 210
 211                 -- Set session.[from/to]_host if they have not been set already and if
 212                 -- this session isn't already authenticated
 213                 if session.type == "s2sin_unauthed" and from and not session.from_host then
 214                         session.from_host = from;
 215                 elseif from ~= session.from_host then
 216                         session:close({ condition = "improper-addressing", text = "New stream 'from' attribute does not match original" });
 217                         return;
 218                 end
 219                 if session.type == "s2sin_unauthed" and to and not session.to_host then
 220                         session.to_host = to;
 221                 elseif to ~= session.to_host then
 222                         session:close({ condition = "improper-addressing", text = "New stream 'to' attribute does not match original" });
 223                         return;
 224                 end
 225
 226                 -- For convenience we'll put the sanitised values into these variables
 227                 to, from = session.to_host, session.from_host;
 228
 229                 session.streamid = uuid_gen();
 230                 (session.log or log)("debug", "Incoming s2s received %s", st.stanza("stream:stream", attr):top_tag());
 231                 if to then
 232                         if not hosts[to] then
 233                                 -- Attempting to connect to a host we don't serve
 234                                 session:close({
 235                                         condition = "host-unknown";
 236                                         text = "This host does not serve "..to
 237                                 });
 238                                 return;
 239                         elseif not hosts[to].modules.s2s then
 240                                 -- Attempting to connect to a host that disallows s2s
 241                                 session:close({
 242                                         condition = "policy-violation";
 243                                         text = "Server-to-server communication is disabled for this host";
 244                                 });
 245                                 return;
 246                         end
 247                 end
 248
 249                 if session.secure and not session.cert_chain_status then check_cert_status(session); end
 250
 251                 session:open_stream()
 252                 if session.version >= 1.0 then
 253                         local features = st.stanza("stream:features");
 254
 255                         if to then
 256                                 hosts[to].events.fire_event("s2s-stream-features", { origin = session, features = features });
 257                         else
 258                                 (session.log or log)("warn", "No 'to' on stream header from %s means we can't offer any features", from or "unknown host");
 259                         end
 260
 261                         log("debug", "Sending stream features: %s", tostring(features));
 262                         send(features);
 263                 end
 264         elseif session.direction == "outgoing" then
 265                 -- If we are just using the connection for verifying dialback keys, we won't try and auth it
 266                 if not attr.id then error("stream response did not give us a streamid!!!"); end
 267                 session.streamid = attr.id;
 268
 269                 if session.secure and not session.cert_chain_status then check_cert_status(session); end
 270
 271                 -- Send unauthed buffer
 272                 -- (stanzas which are fine to send before dialback)
 273                 -- Note that this is *not* the stanza queue (which
 274                 -- we can only send if auth succeeds) :)
 275                 local send_buffer = session.send_buffer;
 276                 if send_buffer and #send_buffer > 0 then
 277                         log("debug", "Sending s2s send_buffer now...");
 278                         for i, data in ipairs(send_buffer) do
 279                                 session.sends2s(tostring(data));
 280                                 send_buffer[i] = nil;
 281                         end
 282                 end
 283                 session.send_buffer = nil;
 284
 285                 -- If server is pre-1.0, don't wait for features, just do dialback
 286                 if session.version < 1.0 then
 287                         if not session.dialback_verifying then
 288                                 hosts[session.from_host].events.fire_event("s2sout-authenticate-legacy", { origin = session });
 289                         else
 290                                 s2s_mark_connected(session);
 291                         end
 292                 end
 293         end
 294         session.notopen = nil;
 295 end
 296
 297 function stream_callbacks.streamclosed(session)
 298         (session.log or log)("debug", "Received </stream:stream>");
 299         session:close(false);
 300 end
 301
 302 function stream_callbacks.error(session, error, data)
 303         if error == "no-stream" then
 304                 session:close("invalid-namespace");
 305         elseif error == "parse-error" then
 306                 session.log("debug", "Server-to-server XML parse error: %s", tostring(error));
 307                 session:close("not-well-formed");
 308         elseif error == "stream-error" then
 309                 local condition, text = "undefined-condition";
 310                 for child in data:children() do
 311                         if child.attr.xmlns == xmlns_xmpp_streams then
 312                                 if child.name ~= "text" then
 313                                         condition = child.name;
 314                                 else
 315                                         text = child:get_text();
 316                                 end
 317                                 if condition ~= "undefined-condition" and text then
 318                                         break;
 319                                 end
 320                         end
 321                 end
 322                 text = condition .. (text and (" ("..text..")") or "");
 323                 session.log("info", "Session closed by remote with error: %s", text);
 324                 session:close(nil, text);
 325         end
 326 end
 327
 328 local function handleerr(err) log("error", "Traceback[s2s]: %s: %s", tostring(err), traceback()); end
 329 function stream_callbacks.handlestanza(session, stanza)
 330         if stanza.attr.xmlns == "jabber:client" then --COMPAT: Prosody pre-0.6.2 may send jabber:client
 331                 stanza.attr.xmlns = nil;
 332         end
 333         stanza = session.filter("stanzas/in", stanza);
 334         if stanza then
 335                 return xpcall(function () return core_process_stanza(session, stanza) end, handleerr);
 336         end
 337 end
 338
 339 local listener = {};
 340
 341 --- Session methods
 342 local stream_xmlns_attr = {xmlns='urn:ietf:params:xml:ns:xmpp-streams'};
 343 local default_stream_attr = { ["xmlns:stream"] = "http://etherx.jabber.org/streams", xmlns = stream_callbacks.default_ns, version = "1.0", id = "" };
 344 local function session_close(session, reason, remote_reason)
 345         local log = session.log or log;
 346         if session.conn then
 347                 if session.notopen then
 348                         session:open_stream()
 349                 end
 350                 if reason then -- nil == no err, initiated by us, false == initiated by remote
 351                         if type(reason) == "string" then -- assume stream error
 352                                 log("debug", "Disconnecting %s[%s], <stream:error> is: %s", session.host or "(unknown host)", session.type, reason);
 353                                 session.sends2s(st.stanza("stream:error"):tag(reason, {xmlns = 'urn:ietf:params:xml:ns:xmpp-streams' }));
 354                         elseif type(reason) == "table" then
 355                                 if reason.condition then
 356                                         local stanza = st.stanza("stream:error"):tag(reason.condition, stream_xmlns_attr):up();
 357                                         if reason.text then
 358                                                 stanza:tag("text", stream_xmlns_attr):text(reason.text):up();
 359                                         end
 360                                         if reason.extra then
 361                                                 stanza:add_child(reason.extra);
 362                                         end
 363                                         log("debug", "Disconnecting %s[%s], <stream:error> is: %s", session.host or "(unknown host)", session.type, tostring(stanza));
 364                                         session.sends2s(stanza);
 365                                 elseif reason.name then -- a stanza
 366                                         log("debug", "Disconnecting %s->%s[%s], <stream:error> is: %s", session.from_host or "(unknown host)", session.to_host or "(unknown host)", session.type, tostring(reason));
 367                                         session.sends2s(reason);
 368                                 end
 369                         end
 370                 end
 371
 372                 session.sends2s("</stream:stream>");
 373                 function session.sends2s() return false; end
 374
 375                 local reason = remote_reason or (reason and (reason.text or reason.condition)) or reason;
 376                 session.log("info", "%s s2s stream %s->%s closed: %s", session.direction, session.from_host or "(unknown host)", session.to_host or "(unknown host)", reason or "stream closed");
 377
 378                 -- Authenticated incoming stream may still be sending us stanzas, so wait for </stream:stream> from remote
 379                 local conn = session.conn;
 380                 if reason == nil and not session.notopen and session.type == "s2sin" then
 381                         add_task(stream_close_timeout, function ()
 382                                 if not session.destroyed then
 383                                         session.log("warn", "Failed to receive a stream close response, closing connection anyway...");
 384                                         s2s_destroy_session(session, reason);
 385                                         conn:close();
 386                                 end
 387                         end);
 388                 else
 389                         s2s_destroy_session(session, reason);
 390                         conn:close(); -- Close immediately, as this is an outgoing connection or is not authed
 391                 end
 392         end
 393 end
 394
 395 function session_open_stream(session, from, to)
 396         local from = from or session.from_host;
 397         local to = to or session.to_host;
 398         local attr = {
 399                 ["xmlns:stream"] = 'http://etherx.jabber.org/streams',
 400                 xmlns = 'jabber:server',
 401                 version = session.version and (session.version > 0 and "1.0" or nil),
 402                 ["xml:lang"] = 'en',
 403                 id = session.streamid,
 404                 from = from, to = to,
 405         }
 406         local local_host = session.direction == "outgoing" and from or to;
 407         if not local_host or hosts[local_host].modules.dialback then
 408                 attr["xmlns:db"] = 'jabber:server:dialback';
 409         end
 410
 411         session.sends2s("<?xml version='1.0'?>");
 412         session.sends2s(st.stanza("stream:stream", attr):top_tag());
 413         return true;
 414 end
 415
 416 -- Session initialization logic shared by incoming and outgoing
 417 local function initialize_session(session)
 418         local stream = new_xmpp_stream(session, stream_callbacks);
 419         session.stream = stream;
 420
 421         session.notopen = true;
 422
 423         function session.reset_stream()
 424                 session.notopen = true;
 425                 session.stream:reset();
 426         end
 427
 428         session.open_stream = session_open_stream;
 429
 430         local filter = session.filter;
 431         function session.data(data)
 432                 data = filter("bytes/in", data);
 433                 if data then
 434                         local ok, err = stream:feed(data);
 435                         if ok then return; end
 436                         (session.log or log)("warn", "Received invalid XML: %s", data);
 437                         (session.log or log)("warn", "Problem was: %s", err);
 438                         session:close("not-well-formed");
 439                 end
 440         end
 441
 442         session.close = session_close;
 443
 444         local handlestanza = stream_callbacks.handlestanza;
 445         function session.dispatch_stanza(session, stanza)
 446                 return handlestanza(session, stanza);
 447         end
 448
 449         add_task(connect_timeout, function ()
 450                 if session.type == "s2sin" or session.type == "s2sout" then
 451                         return; -- Ok, we're connected
 452                 elseif session.type == "s2s_destroyed" then
 453                         return; -- Session already destroyed
 454                 end
 455                 -- Not connected, need to close session and clean up
 456                 (session.log or log)("debug", "Destroying incomplete session %s->%s due to inactivity",
 457                 session.from_host or "(unknown)", session.to_host or "(unknown)");
 458                 session:close("connection-timeout");
 459         end);
 460 end
 461
 462 function listener.onconnect(conn)
 463         local session = sessions[conn];
 464         if not session then -- New incoming connection
 465                 session = s2s_new_incoming(conn);
 466                 sessions[conn] = session;
 467                 session.log("debug", "Incoming s2s connection");
 468
 469                 local filter = initialize_filters(session);
 470                 local w = conn.write;
 471                 session.sends2s = function (t)
 472                         log("debug", "sending: %s", t.top_tag and t:top_tag() or t:match("^([^>]*>?)"));
 473                         if t.name then
 474                                 t = filter("stanzas/out", t);
 475                         end
 476                         if t then
 477                                 t = filter("bytes/out", tostring(t));
 478                                 if t then
 479                                         return w(conn, t);
 480                                 end
 481                         end
 482                 end
 483
 484                 initialize_session(session);
 485         else -- Outgoing session connected
 486                 session:open_stream(session.from_host, session.to_host);
 487         end
 488 end
 489
 490 function listener.onincoming(conn, data)
 491         local session = sessions[conn];
 492         if session then
 493                 session.data(data);
 494         end
 495 end
 496
 497 function listener.onstatus(conn, status)
 498         if status == "ssl-handshake-complete" then
 499                 local session = sessions[conn];
 500                 if session and session.direction == "outgoing" then
 501                         session.log("debug", "Sending stream header...");
 502                         session:open_stream(session.from_host, session.to_host);
 503                 end
 504         end
 505 end
 506
 507 function listener.ondisconnect(conn, err)
 508         local session = sessions[conn];
 509         if session then
 510                 sessions[conn] = nil;
 511                 if err and session.direction == "outgoing" and session.notopen then
 512                         (session.log or log)("debug", "s2s connection attempt failed: %s", err);
 513                         if s2sout.attempt_connection(session, err) then
 514                                 (session.log or log)("debug", "...so we're going to try another target");
 515                                 return; -- Session lives for now
 516                         end
 517                 end
 518                 (session.log or log)("debug", "s2s disconnected: %s->%s (%s)", tostring(session.from_host), tostring(session.to_host), tostring(err or "connection closed"));
 519                 s2s_destroy_session(session, err);
 520         end
 521 end
 522
 523 function listener.register_outgoing(conn, session)
 524         session.direction = "outgoing";
 525         sessions[conn] = session;
 526         initialize_session(session);
 527 end
 528
 529 s2sout.set_listener(listener);
 530
 531 module:hook("server-stopping", function(event)
 532         local reason = event.reason;
 533         for _, session in pairs(sessions) do
 534                 session:close{ condition = "system-shutdown", text = reason };
 535         end
 536 end,500);
 537
 538
 539
 540 module:provides("net", {
 541         name = "s2s";
 542         listener = listener;
 543         default_port = 5269;
 544         encryption = "starttls";
 545         multiplex = {
 546                 pattern = "^<.*:stream.*%sxmlns%s*=%s*(['\"])jabber:server%1.*>";
 547         };
 548 });
 549