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 #ifdef HAVE_OPENSSL
 149         if (!CC->redirect_ssl) {
 150                 cprintf("<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'></starttls>");
 151         }
 152 #endif
 153
 154         if (!CC->logged_in) {
 155                 /* If we're not logged in yet, offer SASL as our feature set */
 156                 xmpp_output_auth_mechs();
 157
 158                 /* Also offer non-SASL authentication */
 159                 cprintf("<auth xmlns=\"http://jabber.org/features/iq-auth\"/>");
 160         }
 161
 162         /* Offer binding and sessions as part of our feature set */
 163         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\"/>");
 164         cprintf("<session xmlns=\"urn:ietf:params:xml:ns:xmpp-session\"/>");
 165
 166         cprintf("</stream:features>");
 167
 168         CC->is_async = 1;               /* XMPP sessions are inherently async-capable */
 169 }
 170
 171
 172 void xmpp_xml_start(void *data, const char *supplied_el, const char **attr) {
 173         char el[256];
 174         char *sep = NULL;
 175         int i;
 176
 177         /* Axe the namespace, we don't care about it */
 178         safestrncpy(el, supplied_el, sizeof el);
 179         while (sep = strchr(el, ':'), sep) {
 180                 strcpy(el, ++sep);
 181         }
 182
 183         /*
 184         syslog(LOG_DEBUG, "XMPP ELEMENT START: <%s>\n", el);
 185         for (i=0; attr[i] != NULL; i+=2) {
 186                 syslog(LOG_DEBUG, "                    Attribute '%s' = '%s'\n", attr[i], attr[i+1]);
 187         }
 188         uncomment for more verbosity */
 189
 190         if (!strcasecmp(el, "stream")) {
 191                 xmpp_stream_start(data, supplied_el, attr);
 192         }
 193
 194         else if (!strcasecmp(el, "query")) {
 195                 XMPP->iq_query_xmlns[0] = 0;
 196                 safestrncpy(XMPP->iq_query_xmlns, supplied_el, sizeof XMPP->iq_query_xmlns);
 197         }
 198
 199         else if (!strcasecmp(el, "bind")) {
 200                 XMPP->bind_requested = 1;
 201         }
 202
 203         else if (!strcasecmp(el, "iq")) {
 204                 for (i=0; attr[i] != NULL; i+=2) {
 205                         if (!strcasecmp(attr[i], "type")) {
 206                                 safestrncpy(XMPP->iq_type, attr[i+1], sizeof XMPP->iq_type);
 207                         }
 208                         else if (!strcasecmp(attr[i], "id")) {
 209                                 safestrncpy(XMPP->iq_id, attr[i+1], sizeof XMPP->iq_id);
 210                         }
 211                         else if (!strcasecmp(attr[i], "from")) {
 212                                 safestrncpy(XMPP->iq_from, attr[i+1], sizeof XMPP->iq_from);
 213                         }
 214                         else if (!strcasecmp(attr[i], "to")) {
 215                                 safestrncpy(XMPP->iq_to, attr[i+1], sizeof XMPP->iq_to);
 216                         }
 217                 }
 218         }
 219
 220         else if (!strcasecmp(el, "auth")) {
 221                 XMPP->sasl_auth_mech[0] = 0;
 222                 for (i=0; attr[i] != NULL; i+=2) {
 223                         if (!strcasecmp(attr[i], "mechanism")) {
 224                                 safestrncpy(XMPP->sasl_auth_mech, attr[i+1], sizeof XMPP->sasl_auth_mech);
 225                         }
 226                 }
 227         }
 228
 229         else if (!strcasecmp(el, "message")) {
 230                 for (i=0; attr[i] != NULL; i+=2) {
 231                         if (!strcasecmp(attr[i], "to")) {
 232                                 safestrncpy(XMPP->message_to, attr[i+1], sizeof XMPP->message_to);
 233                         }
 234                 }
 235         }
 236
 237         else if (!strcasecmp(el, "html")) {
 238                 ++XMPP->html_tag_level;
 239         }
 240 }
 241
 242
 243
 244 void xmpp_xml_end(void *data, const char *supplied_el) {
 245         char el[256];
 246         char *sep = NULL;
 247         char xmlbuf[256];
 248
 249         /* Axe the namespace, we don't care about it */
 250         safestrncpy(el, supplied_el, sizeof el);
 251         while (sep = strchr(el, ':'), sep) {
 252                 strcpy(el, ++sep);
 253         }
 254
 255         /*
 256         syslog(LOG_DEBUG, "XMPP ELEMENT END  : <%s>\n", el);
 257         if (XMPP->chardata_len > 0) {
 258                 syslog(LOG_DEBUG, "          chardata: %s\n", XMPP->chardata);
 259         }
 260         uncomment for more verbosity */
 261
 262         if (!strcasecmp(el, "resource")) {
 263                 if (XMPP->chardata_len > 0) {
 264                         safestrncpy(XMPP->iq_client_resource, XMPP->chardata,
 265                                 sizeof XMPP->iq_client_resource);
 266                         striplt(XMPP->iq_client_resource);
 267                 }
 268         }
 269
 270         else if (!strcasecmp(el, "username")) {         /* NON SASL ONLY */
 271                 if (XMPP->chardata_len > 0) {
 272                         safestrncpy(XMPP->iq_client_username, XMPP->chardata,
 273                                 sizeof XMPP->iq_client_username);
 274                         striplt(XMPP->iq_client_username);
 275                 }
 276         }
 277
 278         else if (!strcasecmp(el, "password")) {         /* NON SASL ONLY */
 279                 if (XMPP->chardata_len > 0) {
 280                         safestrncpy(XMPP->iq_client_password, XMPP->chardata,
 281                                 sizeof XMPP->iq_client_password);
 282                         striplt(XMPP->iq_client_password);
 283                 }
 284         }
 285
 286         else if (!strcasecmp(el, "iq")) {
 287
 288                 /*
 289                  * iq type="get" (handle queries)
 290                  */
 291                 if (!strcasecmp(XMPP->iq_type, "get")) {
 292
 293                         /*
 294                          * Query on a namespace
 295                          */
 296                         if (!IsEmptyStr(XMPP->iq_query_xmlns)) {
 297                                 xmpp_query_namespace(XMPP->iq_id, XMPP->iq_from,
 298                                                 XMPP->iq_to, XMPP->iq_query_xmlns);
 299                         }
 300
 301                         /*
 302                          * ping ( http://xmpp.org/extensions/xep-0199.html )
 303                          */
 304                         else if (XMPP->ping_requested) {
 305                                 cprintf("<iq type=\"result\" ");
 306                                 if (!IsEmptyStr(XMPP->iq_from)) {
 307                                         cprintf("to=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_from, sizeof xmlbuf));
 308                                 }
 309                                 if (!IsEmptyStr(XMPP->iq_to)) {
 310                                         cprintf("from=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_to, sizeof xmlbuf));
 311                                 }
 312                                 cprintf("id=\"%s\"/>", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 313                         }
 314
 315                         /*
 316                          * Unknown query ... return the XML equivalent of a blank stare
 317                          */
 318                         else {
 319                                 syslog(LOG_DEBUG,
 320                                         "Unknown query <%s> - returning <service-unavailable/>\n",
 321                                         el
 322                                 );
 323                                 cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 324                                 cprintf("<error code=\"503\" type=\"cancel\">"
 325                                         "<service-unavailable xmlns=\"urn:ietf:params:xml:ns:xmpp-stanzas\"/>"
 326                                         "</error>"
 327                                 );
 328                                 cprintf("</iq>");
 329                         }
 330                 }
 331
 332                 /*
 333                  * Non SASL authentication
 334                  */
 335                 else if (
 336                         (!strcasecmp(XMPP->iq_type, "set"))
 337                         && (!strcasecmp(XMPP->iq_query_xmlns, "jabber:iq:auth:query"))
 338                         ) {
 339
 340                         xmpp_non_sasl_authenticate(
 341                                 XMPP->iq_id,
 342                                 XMPP->iq_client_username,
 343                                 XMPP->iq_client_password,
 344                                 XMPP->iq_client_resource
 345                         );
 346                 }
 347
 348                 /*
 349                  * If this <iq> stanza was a "bind" attempt, process it ...
 350                  */
 351                 else if (
 352                         (XMPP->bind_requested)
 353                         && (!IsEmptyStr(XMPP->iq_id))
 354                         && (!IsEmptyStr(XMPP->iq_client_resource))
 355                         && (CC->logged_in)
 356                         ) {
 357
 358                         /* Generate the "full JID" of the client resource */
 359
 360                         snprintf(XMPP->client_jid, sizeof XMPP->client_jid,
 361                                 "%s/%s",
 362                                 CC->cs_inet_email,
 363                                 XMPP->iq_client_resource
 364                         );
 365
 366                         /* Tell the client what its JID is */
 367
 368                         cprintf("<iq type=\"result\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 369                         cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\">");
 370                         cprintf("<jid>%s</jid>", xmlesc(xmlbuf, XMPP->client_jid, sizeof xmlbuf));
 371                         cprintf("</bind>");
 372                         cprintf("</iq>");
 373                 }
 374
 375                 else if (XMPP->iq_session) {
 376                         cprintf("<iq type=\"result\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 377                         cprintf("</iq>");
 378                 }
 379
 380                 else {
 381                         cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
 382                         cprintf("<error>Don't know howto do '%s'!</error>", xmlesc(xmlbuf, XMPP->iq_type, sizeof xmlbuf));
 383                         cprintf("</iq>");
 384                 }
 385
 386                 /* Now clear these fields out so they don't get used by a future stanza */
 387                 XMPP->iq_id[0] = 0;
 388                 XMPP->iq_from[0] = 0;
 389                 XMPP->iq_to[0] = 0;
 390                 XMPP->iq_type[0] = 0;
 391                 XMPP->iq_client_resource[0] = 0;
 392                 XMPP->iq_session = 0;
 393                 XMPP->iq_query_xmlns[0] = 0;
 394                 XMPP->bind_requested = 0;
 395                 XMPP->ping_requested = 0;
 396         }
 397
 398         else if (!strcasecmp(el, "auth")) {
 399
 400                 /* Try to authenticate (this function is responsible for the output stanza) */
 401                 xmpp_sasl_auth(XMPP->sasl_auth_mech, (XMPP->chardata != NULL ? XMPP->chardata : "") );
 402
 403                 /* Now clear these fields out so they don't get used by a future stanza */
 404                 XMPP->sasl_auth_mech[0] = 0;
 405         }
 406
 407         else if (!strcasecmp(el, "session")) {
 408                 XMPP->iq_session = 1;
 409         }
 410
 411         else if (!strcasecmp(el, "presence")) {
 412
 413                 /* Respond to a <presence> update by firing back with presence information
 414                  * on the entire wholist.  Check this assumption, it's probably wrong.
 415                  */
 416                 xmpp_wholist_presence_dump();
 417         }
 418
 419         else if ( (!strcasecmp(el, "body")) && (XMPP->html_tag_level == 0) ) {
 420                 if (XMPP->message_body != NULL) {
 421                         free(XMPP->message_body);
 422                         XMPP->message_body = NULL;
 423                 }
 424                 if (XMPP->chardata_len > 0) {
 425                         XMPP->message_body = strdup(XMPP->chardata);
 426                 }
 427         }
 428
 429         else if (!strcasecmp(el, "message")) {
 430                 xmpp_send_message(XMPP->message_to, XMPP->message_body);
 431                 XMPP->html_tag_level = 0;
 432         }
 433
 434         else if (!strcasecmp(el, "html")) {
 435                 --XMPP->html_tag_level;
 436         }
 437
 438         else if (!strcasecmp(el, "starttls")) {
 439 #ifdef HAVE_OPENSSL
 440                 cprintf("<proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
 441                 CtdlModuleStartCryptoMsgs(NULL, NULL, NULL);
 442                 if (!CC->redirect_ssl) CC->kill_me = KILLME_NO_CRYPTO;
 443 #else
 444                 cprintf("<failure xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
 445                 CC->kill_me = KILLME_NO_CRYPTO;
 446 #endif
 447         }
 448
 449         else if (!strcasecmp(el, "ping")) {
 450                 XMPP->ping_requested = 1;
 451         }
 452
 453         else if (!strcasecmp(el, "stream")) {
 454                 syslog(LOG_DEBUG, "XMPP client shut down their stream\n");
 455                 xmpp_massacre_roster();
 456                 cprintf("</stream>\n");
 457                 CC->kill_me = KILLME_CLIENT_LOGGED_OUT;
 458         }
 459
 460         else {
 461                 syslog(LOG_DEBUG, "Ignoring unknown tag <%s>\n", el);
 462         }
 463
 464         XMPP->chardata_len = 0;
 465         if (XMPP->chardata_alloc > 0) {
 466                 XMPP->chardata[0] = 0;
 467         }
 468 }
 469
 470
 471 void xmpp_xml_chardata(void *data, const XML_Char *s, int len)
 472 {
 473         citxmpp *X = XMPP;
 474
 475         if (X->chardata_alloc == 0) {
 476                 X->chardata_alloc = SIZ;
 477                 X->chardata = malloc(X->chardata_alloc);
 478         }
 479         if ((X->chardata_len + len + 1) > X->chardata_alloc) {
 480                 X->chardata_alloc = X->chardata_len + len + 1024;
 481                 X->chardata = realloc(X->chardata, X->chardata_alloc);
 482         }
 483         memcpy(&X->chardata[X->chardata_len], s, len);
 484         X->chardata_len += len;
 485         X->chardata[X->chardata_len] = 0;
 486 }
 487
 488
 489 /*
 490  * This cleanup function blows away the temporary memory and files used by the XMPP service.
 491  */
 492 void xmpp_cleanup_function(void) {
 493
 494         /* Don't do this stuff if this is not a XMPP session! */
 495         if (CC->h_command_function != xmpp_command_loop) return;
 496
 497         if (XMPP->chardata != NULL) {
 498                 free(XMPP->chardata);
 499                 XMPP->chardata = NULL;
 500                 XMPP->chardata_len = 0;
 501                 XMPP->chardata_alloc = 0;
 502                 if (XMPP->message_body != NULL) {
 503                         free(XMPP->message_body);
 504                 }
 505         }
 506         XML_ParserFree(XMPP->xp);
 507         free(XMPP);
 508 }
 509
 510
 511
 512 /*
 513  * Here's where our XMPP session begins its happy day.
 514  */
 515 void xmpp_greeting(void) {
 516         client_set_inbound_buf(4);
 517         strcpy(CC->cs_clientname, "XMPP session");
 518         CC->session_specific_data = malloc(sizeof(citxmpp));
 519         memset(XMPP, 0, sizeof(citxmpp));
 520         XMPP->last_event_processed = queue_event_seq;
 521
 522         /* XMPP does not use a greeting, but we still have to initialize some things. */
 523
 524         XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
 525         if (XMPP->xp == NULL) {
 526                 syslog(LOG_ALERT, "Cannot create XML parser!\n");
 527                 CC->kill_me = KILLME_XML_PARSER;
 528                 return;
 529         }
 530
 531         XML_SetElementHandler(XMPP->xp, xmpp_xml_start, xmpp_xml_end);
 532         XML_SetCharacterDataHandler(XMPP->xp, xmpp_xml_chardata);
 533         // XML_SetUserData(XMPP->xp, something...);
 534
 535         CC->can_receive_im = 1;         /* This protocol is capable of receiving instant messages */
 536 }
 537
 538
 539 /*
 540  * Main command loop for XMPP sessions.
 541  */
 542 void xmpp_command_loop(void) {
 543         int rc;
 544         StrBuf *stream_input = NewStrBuf();
 545
 546         time(&CC->lastcmd);
 547         rc = client_read_random_blob(stream_input, 30);
 548         if (rc > 0) {
 549                 XML_Parse(XMPP->xp, ChrPtr(stream_input), rc, 0);
 550         }
 551         else {
 552                 syslog(LOG_ERR, "Client disconnected: ending session.\n");
 553                 CC->kill_me = KILLME_CLIENT_DISCONNECTED;
 554         }
 555         FreeStrBuf(&stream_input);
 556 }
 557
 558
 559 /*
 560  * Async loop for XMPP sessions (handles the transmission of unsolicited stanzas)
 561  */
 562 void xmpp_async_loop(void) {
 563         xmpp_process_events();
 564         xmpp_output_incoming_messages();
 565 }
 566
 567
 568 /*
 569  * Login hook for XMPP sessions
 570  */
 571 void xmpp_login_hook(void) {
 572         xmpp_queue_event(XMPP_EVT_LOGIN, CC->cs_inet_email);
 573 }
 574
 575
 576 /*
 577  * Logout hook for XMPP sessions
 578  */
 579 void xmpp_logout_hook(void) {
 580         xmpp_queue_event(XMPP_EVT_LOGOUT, CC->cs_inet_email);
 581 }
 582
 583
 584 const char *CitadelServiceXMPP="XMPP";
 585 extern void xmpp_cleanup_events(void);
 586 CTDL_MODULE_INIT(xmpp)
 587 {
 588         if (!threading) {
 589                 CtdlRegisterServiceHook(config.c_xmpp_c2s_port,
 590                                         NULL,
 591                                         xmpp_greeting,
 592                                         xmpp_command_loop,
 593                                         xmpp_async_loop,
 594                                         CitadelServiceXMPP
 595                 );
 596                 CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP);
 597                 CtdlRegisterSessionHook(xmpp_login_hook, EVT_LOGIN);
 598                 CtdlRegisterSessionHook(xmpp_logout_hook, EVT_LOGOUT);
 599                 CtdlRegisterSessionHook(xmpp_login_hook, EVT_UNSTEALTH);
 600                 CtdlRegisterSessionHook(xmpp_logout_hook, EVT_STEALTH);
 601                 CtdlRegisterCleanupHook(xmpp_cleanup_events);
 602
 603         }
 604
 605         /* return our Subversion id for the Log */
 606         return "xmpp";
 607 }