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