citadel/modules/xmpp/serv_xmpp.c

   1 /*
   2  * XMPP (Jabber) service for the Citadel system
   3  * Copyright (c) 2007-2010 by Art Cancro
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 3 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include "sysdep.h"
  21 #include <stdlib.h>
  22 #include <unistd.h>
  23 #include <stdio.h>
  24 #include <fcntl.h>
  25 #include <signal.h>
  26 #include <pwd.h>
  27 #include <errno.h>
  28 #include <sys/types.h>
  29
  30 #if TIME_WITH_SYS_TIME
  31 # include <sys/time.h>
  32 # include <time.h>
  33 #else
  34 # if HAVE_SYS_TIME_H
  35 #  include <sys/time.h>
  36 # else
  37 #  include <time.h>
  38 # endif
  39 #endif
  40
  41 #include <sys/wait.h>
  42 #include <string.h>
  43 #include <limits.h>
  44 #include <ctype.h>
  45 #include <libcitadel.h>
  46 #include <expat.h>
  47 #include "citadel.h"
  48 #include "server.h"
  49 #include "citserver.h"
  50 #include "support.h"
  51 #include "config.h"
  52 #include "user_ops.h"
  53 #include "database.h"
  54 #include "msgbase.h"
  55 #include "internet_addressing.h"
  56 #include "md5.h"
  57 #include "ctdl_module.h"
  58 #include "serv_xmpp.h"
  59
  60 struct xmpp_event *xmpp_queue = NULL;
  61
  62 /*
  63  * Given a source string and a target buffer, returns the string
  64  * properly escaped for insertion into an XML stream.  Returns a
  65  * pointer to the target buffer for convenience.
  66  *
  67  * BUG: this does not properly handle UTF-8
  68  */
  69 char *xmlesc(char *buf, char *str, int bufsiz)
  70 {
  71         char *ptr;
  72         unsigned char ch;
  73         int len = 0;
  74
  75         if (!buf) return(NULL);
  76         buf[0] = 0;
  77         len = 0;
  78         if (!str) {
  79                 return(buf);
  80         }
  81
  82         for (ptr=str; *ptr; ptr++) {
  83                 ch = *ptr;
  84                 if (ch == '<') {
  85                         strcpy(&buf[len], "&lt;");
  86                         len += 4;
  87                 }
  88                 else if (ch == '>') {
  89                         strcpy(&buf[len], "&gt;");
  90                         len += 4;
  91                 }
  92                 else if (ch == '&') {
  93                         strcpy(&buf[len], "&amp;");
  94                         len += 5;
  95                 }
  96                 else if ((ch >= 0x20) && (ch <= 0x7F)) {
  97                         buf[len++] = ch;
  98                         buf[len] = 0;
  99                 }
 100                 else if (ch < 0x20) {
 101                         /* we probably shouldn't be doing this */
 102                         buf[len++] = '_';
 103                         buf[len] = 0;
 104                 }
 105                 else {
 106                         char oct[10];
 107                         sprintf(oct, "&#%o;", ch);
 108                         strcpy(&buf[len], oct);
 109                         len += strlen(oct);
 110                 }
 111                 if ((len + 6) > bufsiz) {
 112                         return(buf);
 113                 }
 114         }
 115         return(buf);
 116 }
 117
 118
 119 /*
 120  * We have just received a <stream> tag from the client, so send them ours
 121  */
 122 void xmpp_stream_start(void *data, const char *supplied_el, const char **attr)
 123 {
 124         char xmlbuf[256];
 125
 126         while (*attr) {
 127                 if (!strcasecmp(attr[0], "to")) {
 128                         safestrncpy(XMPP->server_name, attr[1], sizeof XMPP->server_name);
 129                 }
 130                 attr += 2;
 131         }
 132
 133         cprintf("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
 134
 135         cprintf("<stream:stream ");
 136         cprintf("from=\"%s\" ", xmlesc(xmlbuf, XMPP->server_name, sizeof xmlbuf));
 137         cprintf("id=\"%08x\" ", CC->cs_pid);
 138         cprintf("version=\"1.0\" ");
 139         cprintf("xmlns:stream=\"http://etherx.jabber.org/streams\" ");
 140         cprintf("xmlns=\"jabber:client\">");
 141
 142         /* The features of this stream are... */
 143         cprintf("<stream:features>");
 144
 145         /*
 146          * TLS encryption (but only if it isn't already active)
 147          *
 148          * NOTE: if TLS doesn't handshake properly for whatever reason,
 149          * comment out these three lines to disable it at the server.
 150          */
 151         if (!CC->redirect_ssl) {
 152                 cprintf("<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'></starttls>");
 153         }
 154
 155         if (!CC->logged_in) {
 156                 /* If we're not logged in yet, offer SASL as our feature set */
 157                 xmpp_output_auth_mechs();
 158
 159                 /* Also offer non-SASL authentication */
 160                 cprintf("<auth xmlns=\"http://jabber.org/features/iq-auth\"/>");
 161         }
 162
 163         /* Offer binding and sessions as part of our feature set */
 164         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\"/>");
 165         cprintf("<session xmlns=\"urn:ietf:params:xml:ns:xmpp-session\"/>");
 166
 167         cprintf("</stream:features>");
 168
 169         CC->is_async = 1;               /* XMPP sessions are inherently async-capable */
 170 }
 171
 172
 173 void xmpp_xml_start(void *data, const char *supplied_el, const char **attr) {
 174         char el[256];
 175         char *sep = NULL;
 176         int i;
 177
 178         /* Axe the namespace, we don't care about it */
 179         safestrncpy(el, supplied_el, sizeof el);
 180         while (sep = strchr(el, ':'), sep) {
 181                 strcpy(el, ++sep);
 182         }
 183
 184         /*
 185         syslog(LOG_DEBUG, "XMPP ELEMENT START: <%s>\n", el);
 186         for (i=0; attr[i] != NULL; i+=2) {
 187                 syslog(LOG_DEBUG, "                    Attribute '%s' = '%s'\n", attr[i], attr[i+1]);
 188         }
 189         uncomment for more verbosity */
 190
 191         if (!strcasecmp(el, "stream")) {
 192                 xmpp_stream_start(data, supplied_el, attr);
 193         }
 194
 195         else if (!strcasecmp(el, "query")) {
 196                 XMPP->iq_query_xmlns[0] = 0;
 197                 safestrncpy(XMPP->iq_query_xmlns, supplied_el, sizeof XMPP->iq_query_xmlns);
 198         }
 199
 200         else if (!strcasecmp(el, "bind")) {
 201                 XMPP->bind_requested = 1;
 202         }
 203
 204         else if (!strcasecmp(el, "iq")) {
 205                 for (i=0; attr[i] != NULL; i+=2) {
 206                         if (!strcasecmp(attr[i], "type")) {
 207                                 safestrncpy(XMPP->iq_type, attr[i+1], sizeof XMPP->iq_type);
 208                         }
 209                         else if (!strcasecmp(attr[i], "id")) {
 210                                 safestrncpy(XMPP->iq_id, attr[i+1], sizeof XMPP->iq_id);
 211                         }
 212                         else if (!strcasecmp(attr[i], "from")) {
 213                                 safestrncpy(XMPP->iq_from, attr[i+1], sizeof XMPP->iq_from);
 214                         }
 215                         else if (!strcasecmp(attr[i], "to")) {
 216                                 safestrncpy(XMPP->iq_to, attr[i+1], sizeof XMPP->iq_to);
 217                         }
 218                 }
 219         }
 220
 221         else if (!strcasecmp(el, "auth")) {
 222                 XMPP->sasl_auth_mech[0] = 0;
 223                 for (i=0; attr[i] != NULL; i+=2) {
 224                         if (!strcasecmp(attr[i], "mechanism")) {
 225                                 safestrncpy(XMPP->sasl_auth_mech, attr[i+1], sizeof XMPP->sasl_auth_mech);
 226                         }
 227                 }
 228         }
 229
 230         else if (!strcasecmp(el, "message")) {
 231                 for (i=0; attr[i] != NULL; i+=2) {
 232                         if (!strcasecmp(attr[i], "to")) {
 233                                 safestrncpy(XMPP->message_to, attr[i+1], sizeof XMPP->message_to);
 234                         }
 235                 }
 236         }
 237
 238         else if (!strcasecmp(el, "html")) {
 239                 ++XMPP->html_tag_level;
 240         }
 241 }
 242
 243
 244
 245 void xmpp_xml_end(void *data, const char *supplied_el) {
 246         char el[256];
 247         char *sep = NULL;
 248         char xmlbuf[256];
 249
 250         /* Axe the namespace, we don't care about it */
 251         safestrncpy(el, supplied_el, sizeof el);
 252         while (sep = strchr(el, ':'), sep) {
 253                 strcpy(el, ++sep);
 254         }
 255
 256         /*
 257         syslog(LOG_DEBUG, "XMPP ELEMENT END  : <%s>\n", el);
 258         if (XMPP->chardata_len > 0) {
 259                 syslog(LOG_DEBUG, "          chardata: %s\n", XMPP->chardata);
 260         }
 261         uncomment for more verbosity */
 262
 263         if (!strcasecmp(el, "resource")) {
 264                 if (XMPP->chardata_len > 0) {
 265                         safestrncpy(XMPP->iq_client_resource, XMPP->chardata,
 266                                 sizeof XMPP->iq_client_resource);
 267                         striplt(XMPP->iq_client_resource);
 268                 }
 269         }
 270
 271         else if (!strcasecmp(el, "username")) {         /* NON SASL ONLY */
 272                 if (XMPP->chardata_len > 0) {
 273                         safestrncpy(XMPP->iq_client_username, XMPP->chardata,
 274                                 sizeof XMPP->iq_client_username);
 275                         striplt(XMPP->iq_client_username);
 276                 }
 277         }
 278
 279         else if (!strcasecmp(el, "password")) {         /* NON SASL ONLY */
 280                 if (XMPP->chardata_len > 0) {
 281                         safestrncpy(XMPP->iq_client_password, XMPP->chardata,
 282                                 sizeof XMPP->iq_client_password);
 283                         striplt(XMPP->iq_client_password);
 284                 }
 285         }
 286
 287         else if (!strcasecmp(el, "iq")) {
 288
 289                 /*
 290                  * iq type="get" (handle queries)
 291                  */
 292                 if (!strcasecmp(XMPP->iq_type, "get")) {
 293
 294                         /*
 295                          * Query on a namespace
 296                          */
 297                         if (!IsEmptyStr(XMPP->iq_query_xmlns)) {
 298                                 xmpp_query_namespace(XMPP->iq_id, XMPP->iq_from,
 299                                                 XMPP->iq_to, XMPP->iq_query_xmlns);
 300                         }
 301
 302                         /*
 303                          * ping ( http://xmpp.org/extensions/xep-0199.html )
 304                          */
 305                         else if (XMPP->ping_requested) {
 306                                 cprintf("<iq type=\"result\" ");
 307                                 if (!IsEmptyStr(XMPP->iq_from)) {
 308                                         cprintf("to=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_from, sizeof xmlbuf));
 309                                 }
 310                                 if (!IsEmptyStr(XMPP->iq_to)) {
 311                                         cprintf("from=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_to, sizeof xmlbuf));
 312                                 }
 313                                 cprintf("id=\"%s\"/>", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 314                         }
 315
 316                         /*
 317                          * Unknown query ... return the XML equivalent of a blank stare
 318                          */
 319                         else {
 320                                 syslog(LOG_DEBUG,
 321                                         "Unknown query <%s> - returning <service-unavailable/>\n",
 322                                         el
 323                                 );
 324                                 cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 325                                 cprintf("<error code=\"503\" type=\"cancel\">"
 326                                         "<service-unavailable xmlns=\"urn:ietf:params:xml:ns:xmpp-stanzas\"/>"
 327                                         "</error>"
 328                                 );
 329                                 cprintf("</iq>");
 330                         }
 331                 }
 332
 333                 /*
 334                  * Non SASL authentication
 335                  */
 336                 else if (
 337                         (!strcasecmp(XMPP->iq_type, "set"))
 338                         && (!strcasecmp(XMPP->iq_query_xmlns, "jabber:iq:auth:query"))
 339                         ) {
 340
 341                         xmpp_non_sasl_authenticate(
 342                                 XMPP->iq_id,
 343                                 XMPP->iq_client_username,
 344                                 XMPP->iq_client_password,
 345                                 XMPP->iq_client_resource
 346                         );
 347                 }
 348
 349                 /*
 350                  * If this <iq> stanza was a "bind" attempt, process it ...
 351                  */
 352                 else if (
 353                         (XMPP->bind_requested)
 354                         && (!IsEmptyStr(XMPP->iq_id))
 355                         && (!IsEmptyStr(XMPP->iq_client_resource))
 356                         && (CC->logged_in)
 357                         ) {
 358
 359                         /* Generate the "full JID" of the client resource */
 360
 361                         snprintf(XMPP->client_jid, sizeof XMPP->client_jid,
 362                                 "%s/%s",
 363                                 CC->cs_inet_email,
 364                                 XMPP->iq_client_resource
 365                         );
 366
 367                         /* Tell the client what its JID is */
 368
 369                         cprintf("<iq type=\"result\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 370                         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\">");
 371                         cprintf("<jid>%s</jid>", xmlesc(xmlbuf, XMPP->client_jid, sizeof xmlbuf));
 372                         cprintf("</bind>");
 373                         cprintf("</iq>");
 374                 }
 375
 376                 else if (XMPP->iq_session) {
 377                         cprintf("<iq type=\"result\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 378                         cprintf("</iq>");
 379                 }
 380
 381                 else {
 382                         cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 383                         cprintf("<error>Don't know howto do '%s'!</error>", xmlesc(xmlbuf, XMPP->iq_type, sizeof xmlbuf));
 384                         cprintf("</iq>");
 385                 }
 386
 387                 /* Now clear these fields out so they don't get used by a future stanza */
 388                 XMPP->iq_id[0] = 0;
 389                 XMPP->iq_from[0] = 0;
 390                 XMPP->iq_to[0] = 0;
 391                 XMPP->iq_type[0] = 0;
 392                 XMPP->iq_client_resource[0] = 0;
 393                 XMPP->iq_session = 0;
 394                 XMPP->iq_query_xmlns[0] = 0;
 395                 XMPP->bind_requested = 0;
 396                 XMPP->ping_requested = 0;
 397         }
 398
 399         else if (!strcasecmp(el, "auth")) {
 400
 401                 /* Try to authenticate (this function is responsible for the output stanza) */
 402                 xmpp_sasl_auth(XMPP->sasl_auth_mech, (XMPP->chardata != NULL ? XMPP->chardata : "") );
 403
 404                 /* Now clear these fields out so they don't get used by a future stanza */
 405                 XMPP->sasl_auth_mech[0] = 0;
 406         }
 407
 408         else if (!strcasecmp(el, "session")) {
 409                 XMPP->iq_session = 1;
 410         }
 411
 412         else if (!strcasecmp(el, "presence")) {
 413
 414                 /* Respond to a <presence> update by firing back with presence information
 415                  * on the entire wholist.  Check this assumption, it's probably wrong.
 416                  */
 417                 xmpp_wholist_presence_dump();
 418         }
 419
 420         else if ( (!strcasecmp(el, "body")) && (XMPP->html_tag_level == 0) ) {
 421                 if (XMPP->message_body != NULL) {
 422                         free(XMPP->message_body);
 423                         XMPP->message_body = NULL;
 424                 }
 425                 if (XMPP->chardata_len > 0) {
 426                         XMPP->message_body = strdup(XMPP->chardata);
 427                 }
 428         }
 429
 430         else if (!strcasecmp(el, "message")) {
 431                 xmpp_send_message(XMPP->message_to, XMPP->message_body);
 432                 XMPP->html_tag_level = 0;
 433         }
 434
 435         else if (!strcasecmp(el, "html")) {
 436                 --XMPP->html_tag_level;
 437         }
 438
 439         else if (!strcasecmp(el, "starttls")) {
 440 #ifdef HAVE_OPENSSL
 441                 cprintf("<proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
 442                 CtdlModuleStartCryptoMsgs(NULL, NULL, NULL);
 443                 if (!CC->redirect_ssl) CC->kill_me = 1;
 444 #else
 445                 cprintf("<failure xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
 446                 CC->kill_me = 1;
 447 #endif
 448         }
 449
 450         else if (!strcasecmp(el, "ping")) {
 451                 XMPP->ping_requested = 1;
 452         }
 453
 454         else if (!strcasecmp(el, "stream")) {
 455                 syslog(LOG_DEBUG, "XMPP client shut down their stream\n");
 456                 xmpp_massacre_roster();
 457                 cprintf("</stream>\n");
 458                 CC->kill_me = 1;
 459         }
 460
 461         else {
 462                 syslog(LOG_DEBUG, "Ignoring unknown tag <%s>\n", el);
 463         }
 464
 465         XMPP->chardata_len = 0;
 466         if (XMPP->chardata_alloc > 0) {
 467                 XMPP->chardata[0] = 0;
 468         }
 469 }
 470
 471
 472 void xmpp_xml_chardata(void *data, const XML_Char *s, int len)
 473 {
 474         citxmpp *X = XMPP;
 475
 476         if (X->chardata_alloc == 0) {
 477                 X->chardata_alloc = SIZ;
 478                 X->chardata = malloc(X->chardata_alloc);
 479         }
 480         if ((X->chardata_len + len + 1) > X->chardata_alloc) {
 481                 X->chardata_alloc = X->chardata_len + len + 1024;
 482                 X->chardata = realloc(X->chardata, X->chardata_alloc);
 483         }
 484         memcpy(&X->chardata[X->chardata_len], s, len);
 485         X->chardata_len += len;
 486         X->chardata[X->chardata_len] = 0;
 487 }
 488
 489
 490 /*
 491  * This cleanup function blows away the temporary memory and files used by the XMPP service.
 492  */
 493 void xmpp_cleanup_function(void) {
 494
 495         /* Don't do this stuff if this is not a XMPP session! */
 496         if (CC->h_command_function != xmpp_command_loop) return;
 497
 498         if (XMPP->chardata != NULL) {
 499                 free(XMPP->chardata);
 500                 XMPP->chardata = NULL;
 501                 XMPP->chardata_len = 0;
 502                 XMPP->chardata_alloc = 0;
 503                 if (XMPP->message_body != NULL) {
 504                         free(XMPP->message_body);
 505                 }
 506         }
 507         XML_ParserFree(XMPP->xp);
 508         free(XMPP);
 509 }
 510
 511
 512
 513 /*
 514  * Here's where our XMPP session begins its happy day.
 515  */
 516 void xmpp_greeting(void) {
 517         client_set_inbound_buf(4);
 518         strcpy(CC->cs_clientname, "XMPP session");
 519         CC->session_specific_data = malloc(sizeof(citxmpp));
 520         memset(XMPP, 0, sizeof(citxmpp));
 521         XMPP->last_event_processed = queue_event_seq;
 522
 523         /* XMPP does not use a greeting, but we still have to initialize some things. */
 524
 525         XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
 526         if (XMPP->xp == NULL) {
 527                 syslog(LOG_ALERT, "Cannot create XML parser!\n");
 528                 CC->kill_me = 1;
 529                 return;
 530         }
 531
 532         XML_SetElementHandler(XMPP->xp, xmpp_xml_start, xmpp_xml_end);
 533         XML_SetCharacterDataHandler(XMPP->xp, xmpp_xml_chardata);
 534         // XML_SetUserData(XMPP->xp, something...);
 535
 536         CC->can_receive_im = 1;         /* This protocol is capable of receiving instant messages */
 537 }
 538
 539
 540 /*
 541  * Main command loop for XMPP sessions.
 542  */
 543 void xmpp_command_loop(void) {
 544         int rc;
 545         StrBuf *stream_input = NewStrBuf();
 546
 547         time(&CC->lastcmd);
 548         rc = client_read_random_blob(stream_input, 30);
 549         if (rc > 0) {
 550                 XML_Parse(XMPP->xp, ChrPtr(stream_input), rc, 0);
 551         }
 552         else {
 553                 syslog(LOG_ERR, "Client disconnected: ending session.\n");
 554                 CC->kill_me = 1;
 555         }
 556         FreeStrBuf(&stream_input);
 557 }
 558
 559
 560 /*
 561  * Async loop for XMPP sessions (handles the transmission of unsolicited stanzas)
 562  */
 563 void xmpp_async_loop(void) {
 564         xmpp_process_events();
 565         xmpp_output_incoming_messages();
 566 }
 567
 568
 569 /*
 570  * Login hook for XMPP sessions
 571  */
 572 void xmpp_login_hook(void) {
 573         xmpp_queue_event(XMPP_EVT_LOGIN, CC->cs_inet_email);
 574 }
 575
 576
 577 /*
 578  * Logout hook for XMPP sessions
 579  */
 580 void xmpp_logout_hook(void) {
 581         xmpp_queue_event(XMPP_EVT_LOGOUT, CC->cs_inet_email);
 582 }
 583
 584
 585 const char *CitadelServiceXMPP="XMPP";
 586 extern void xmpp_cleanup_events(void);
 587 CTDL_MODULE_INIT(xmpp)
 588 {
 589         if (!threading) {
 590                 CtdlRegisterServiceHook(config.c_xmpp_c2s_port,
 591                                         NULL,
 592                                         xmpp_greeting,
 593                                         xmpp_command_loop,
 594                                         xmpp_async_loop,
 595                                         CitadelServiceXMPP
 596                 );
 597                 CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP);
 598                 CtdlRegisterSessionHook(xmpp_login_hook, EVT_LOGIN);
 599                 CtdlRegisterSessionHook(xmpp_logout_hook, EVT_LOGOUT);
 600                 CtdlRegisterSessionHook(xmpp_login_hook, EVT_UNSTEALTH);
 601                 CtdlRegisterSessionHook(xmpp_logout_hook, EVT_STEALTH);
 602                 CtdlRegisterCleanupHook(xmpp_cleanup_events);
 603
 604         }
 605
 606         /* return our Subversion id for the Log */
 607         return "xmpp";
 608 }