2 * XMPP (Jabber) service for the Citadel system
3 * Copyright (c) 2007-2019 by Art Cancro and citadel.org
5 * This program is open source 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.
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.
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
28 #include <sys/types.h>
30 #if TIME_WITH_SYS_TIME
31 # include <sys/time.h>
35 # include <sys/time.h>
45 #include <libcitadel.h>
49 #include "citserver.h"
55 #include "internet_addressing.h"
56 #include "ctdl_module.h"
57 #include "serv_xmpp.h"
59 /* uncomment for more verbosity - it will log all received XML tags */
60 // #define XMPP_XML_DEBUG
62 /* XML_StopParser is present in expat 2.x */
63 #if XML_MAJOR_VERSION > 1
64 #define HAVE_XML_STOPPARSER
67 struct xmpp_event *xmpp_queue = NULL;
69 #ifdef HAVE_XML_STOPPARSER
70 /* Stop the parser if an entity declaration is hit. */
71 static void xmpp_entity_declaration(void *userData, const XML_Char *entityName,
72 int is_parameter_entity, const XML_Char *value,
73 int value_length, const XML_Char *base,
74 const XML_Char *systemId, const XML_Char *publicId,
75 const XML_Char *notationName
77 syslog(LOG_WARNING, "xmpp: illegal entity declaration encountered; stopping parser.");
78 XML_StopParser(XMPP->xp, XML_FALSE);
84 * support function for xmlesc() which helps with UTF-8 strings
86 static inline int Ctdl_GetUtf8SequenceLength(const char *CharS, const char *CharE)
89 unsigned char test = (1<<7);
91 if ((*CharS & 0xC0) != 0xC0) {
95 while ((n < 8) && ((test & ((unsigned char)*CharS)) != 0)) {
99 if ((n > 6) || ((CharE - CharS) < n)) {
107 * Given a source string and a target buffer, returns the string
108 * properly escaped for insertion into an XML stream. Returns a
109 * pointer to the target buffer for convenience.
111 char *xmlesc(char *buf, char *str, int bufsiz)
119 if (!buf) return(NULL);
128 for (ptr=str; *ptr; ptr++) {
131 strcpy(&buf[len], "<");
134 else if (ch == '>') {
135 strcpy(&buf[len], ">");
138 else if (ch == '&') {
139 strcpy(&buf[len], "&");
142 else if ((ch >= 0x20) && (ch <= 0x7F)) {
146 else if (ch < 0x20) {
147 buf[len++] = '_'; // we probably shouldn't be doing this
151 IsUtf8Sequence = Ctdl_GetUtf8SequenceLength(ptr, pche);
154 while ((IsUtf8Sequence > 0) &&
165 sprintf(oct, "&#%o;", ch);
166 strcpy(&buf[len], oct);
170 if ((len + 6) > bufsiz) {
179 * We have just received a <stream> tag from the client, so send them ours
181 void xmpp_stream_start(void *data, const char *supplied_el, const char **attr)
186 if (!strcasecmp(attr[0], "to")) {
187 safestrncpy(XMPP->server_name, attr[1], sizeof XMPP->server_name);
192 cprintf("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
193 cprintf("<stream:stream ");
194 cprintf("from=\"%s\" ", xmlesc(xmlbuf, XMPP->server_name, sizeof xmlbuf));
195 cprintf("id=\"%08x\" ", CC->cs_pid);
196 cprintf("version=\"1.0\" ");
197 cprintf("xmlns:stream=\"http://etherx.jabber.org/streams\" ");
198 cprintf("xmlns=\"jabber:client\">");
200 /* The features of this stream are... */
201 cprintf("<stream:features>");
204 * TLS encryption (but only if it isn't already active)
207 if (!CC->redirect_ssl) {
208 cprintf("<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'></starttls>");
212 if (!CC->logged_in) {
213 /* If we're not logged in yet, offer SASL as our feature set */
214 xmpp_output_auth_mechs();
216 /* Also offer non-SASL authentication */
217 cprintf("<auth xmlns=\"http://jabber.org/features/iq-auth\"/>");
220 /* Offer binding and sessions as part of our feature set */
221 cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\"/>");
222 cprintf("<session xmlns=\"urn:ietf:params:xml:ns:xmpp-session\"/>");
223 cprintf("</stream:features>");
225 CC->is_async = 1; /* XMPP sessions are inherently async-capable */
229 void xmpp_xml_start(void *data, const char *supplied_el, const char **attr) {
234 /* Create a version of the element with the namespace removed.
235 * Now we can access "el" or "supplied_el" depending on whether we want to see the whole namespace.
237 safestrncpy(el, supplied_el, sizeof el);
238 while (sep = strchr(el, ':'), sep) {
242 #ifdef XMPP_XML_DEBUG
243 syslog(LOG_DEBUG, "xmpp: ELEMENT START: <%s>", el);
244 for (i=0; attr[i] != NULL; i+=2) {
245 syslog(LOG_DEBUG, "xmpp: Attribute '%s' = '%s'", attr[i], attr[i+1]);
249 if (!strcasecmp(el, "stream")) {
250 xmpp_stream_start(data, supplied_el, attr);
253 else if (!strcasecmp(el, "query")) {
254 XMPP->iq_query_xmlns[0] = 0;
255 safestrncpy(XMPP->iq_query_xmlns, supplied_el, sizeof XMPP->iq_query_xmlns);
258 else if (!strcasecmp(el, "bind")) {
259 XMPP->bind_requested = 1;
262 else if (!strcasecmp(el, "iq")) {
263 for (i=0; attr[i] != NULL; i+=2) {
264 if (!strcasecmp(attr[i], "type")) {
265 safestrncpy(XMPP->iq_type, attr[i+1], sizeof XMPP->iq_type);
267 else if (!strcasecmp(attr[i], "id")) {
268 safestrncpy(XMPP->iq_id, attr[i+1], sizeof XMPP->iq_id);
270 else if (!strcasecmp(attr[i], "from")) {
271 safestrncpy(XMPP->iq_from, attr[i+1], sizeof XMPP->iq_from);
273 else if (!strcasecmp(attr[i], "to")) {
274 safestrncpy(XMPP->iq_to, attr[i+1], sizeof XMPP->iq_to);
279 else if (!strcasecmp(el, "auth")) {
280 XMPP->sasl_auth_mech[0] = 0;
281 for (i=0; attr[i] != NULL; i+=2) {
282 if (!strcasecmp(attr[i], "mechanism")) {
283 safestrncpy(XMPP->sasl_auth_mech, attr[i+1], sizeof XMPP->sasl_auth_mech);
288 else if (!strcasecmp(el, "message")) {
289 for (i=0; attr[i] != NULL; i+=2) {
290 if (!strcasecmp(attr[i], "to")) {
291 safestrncpy(XMPP->message_to, attr[i+1], sizeof XMPP->message_to);
296 else if (!strcasecmp(el, "html")) {
297 ++XMPP->html_tag_level;
302 void xmpp_xml_end(void *data, const char *supplied_el) {
307 /* Create a version of the element with the namespace removed.
308 * Now we can access "el" or "supplied_el" depending on whether we want to see the whole namespace.
310 safestrncpy(el, supplied_el, sizeof el);
311 while (sep = strchr(el, ':'), sep) {
315 #ifdef XMPP_XML_DEBUG
316 syslog(LOG_DEBUG, "xmpp: ELEMENT END : <%s>", el);
317 if (XMPP->chardata_len > 0) {
318 syslog(LOG_DEBUG, "xmpp: chardata: %s", XMPP->chardata);
322 if (!strcasecmp(el, "resource")) {
323 if (XMPP->chardata_len > 0) {
324 safestrncpy(XMPP->iq_client_resource, XMPP->chardata, sizeof XMPP->iq_client_resource);
325 striplt(XMPP->iq_client_resource);
329 else if (!strcasecmp(el, "username")) { /* NON SASL ONLY */
330 if (XMPP->chardata_len > 0) {
331 safestrncpy(XMPP->iq_client_username, XMPP->chardata, sizeof XMPP->iq_client_username);
332 striplt(XMPP->iq_client_username);
336 else if (!strcasecmp(el, "password")) { /* NON SASL ONLY */
337 if (XMPP->chardata_len > 0) {
338 safestrncpy(XMPP->iq_client_password, XMPP->chardata, sizeof XMPP->iq_client_password);
339 striplt(XMPP->iq_client_password);
343 else if (!strcasecmp(el, "iq")) {
346 * iq type="get" (handle queries)
348 if (!strcasecmp(XMPP->iq_type, "get")) {
351 * Query on a namespace
353 if (!IsEmptyStr(XMPP->iq_query_xmlns)) {
354 xmpp_query_namespace(XMPP->iq_id, XMPP->iq_from, XMPP->iq_to, XMPP->iq_query_xmlns);
358 * ping ( http://xmpp.org/extensions/xep-0199.html )
360 else if (XMPP->ping_requested) {
361 cprintf("<iq type=\"result\" ");
362 if (!IsEmptyStr(XMPP->iq_from)) {
363 cprintf("to=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_from, sizeof xmlbuf));
365 if (!IsEmptyStr(XMPP->iq_to)) {
366 cprintf("from=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_to, sizeof xmlbuf));
368 cprintf("id=\"%s\"/>", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
372 * Client is requesting its own vCard
373 * (If we make this more elaborate, move it to a separate function)
375 else if (XMPP->iq_vcard) {
376 cprintf("<iq type=\"result\" id=\"%s\" ", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
377 cprintf("to=\"%s\">", xmlesc(xmlbuf, XMPP->iq_from, sizeof xmlbuf));
378 cprintf("<vCard xmlns=\"vcard-temp\">");
379 cprintf("<fn>%s</fn>", xmlesc(xmlbuf, CC->user.fullname, sizeof xmlbuf));
380 cprintf("<nickname>%s</nickname>", xmlesc(xmlbuf, CC->user.fullname, sizeof xmlbuf));
386 * Unknown query ... return the XML equivalent of a blank stare
389 syslog(LOG_DEBUG, "xmpp: Unknown query <%s> - returning <service-unavailable/>", el);
390 cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
391 cprintf("<error code=\"503\" type=\"cancel\">"
392 "<service-unavailable xmlns=\"urn:ietf:params:xml:ns:xmpp-stanzas\"/>"
400 * Non SASL authentication
403 (!strcasecmp(XMPP->iq_type, "set"))
404 && (!strcasecmp(XMPP->iq_query_xmlns, "jabber:iq:auth:query"))
406 xmpp_non_sasl_authenticate(XMPP->iq_id, XMPP->iq_client_username, XMPP->iq_client_password);
410 * If this <iq> stanza was a "bind" attempt, process it ...
413 (XMPP->bind_requested)
414 && (!IsEmptyStr(XMPP->iq_id))
417 /* If the client has not specified a client resource, generate one */
418 if (IsEmptyStr(XMPP->iq_client_resource)) {
419 snprintf(XMPP->iq_client_resource, sizeof XMPP->iq_client_resource, "%d", CC->cs_pid);
422 /* Generate the "full JID" of the client (user@host/resource) */
423 snprintf(XMPP->client_jid, sizeof XMPP->client_jid, "%s/%s", CC->cs_inet_email, XMPP->iq_client_resource);
425 /* Tell the client what its JID is */
426 cprintf("<iq type=\"result\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
427 cprintf("<bind xmlns=\"urn:ietf:params:xml:ns:xmpp-bind\">");
428 cprintf("<jid>%s</jid>", xmlesc(xmlbuf, XMPP->client_jid, sizeof xmlbuf));
433 else if (XMPP->iq_session) {
434 cprintf("<iq type=\"result\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
439 cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
440 cprintf("<error>Don't know how to do '%s'!</error>", xmlesc(xmlbuf, XMPP->iq_type, sizeof xmlbuf));
442 syslog(LOG_DEBUG, "XMPP: don't know how to do iq_type='%s' with iq_query_xmlns='%s'", XMPP->iq_type, XMPP->iq_query_xmlns);
445 /* Now clear these fields out so they don't get used by a future stanza */
447 XMPP->iq_from[0] = 0;
449 XMPP->iq_type[0] = 0;
450 XMPP->iq_client_resource[0] = 0;
451 XMPP->iq_session = 0;
453 XMPP->iq_query_xmlns[0] = 0;
454 XMPP->bind_requested = 0;
455 XMPP->ping_requested = 0;
458 else if (!strcasecmp(el, "auth")) {
459 /* Try to authenticate (this function is responsible for the output stanza) */
460 xmpp_sasl_auth(XMPP->sasl_auth_mech, (XMPP->chardata != NULL ? XMPP->chardata : "") );
462 /* Now clear these fields out so they don't get used by a future stanza */
463 XMPP->sasl_auth_mech[0] = 0;
466 else if (!strcasecmp(el, "session")) {
467 XMPP->iq_session = 1;
470 else if (!strcasecmp(supplied_el, "vcard-temp:vCard")) {
474 else if (!strcasecmp(el, "presence")) {
475 /* Respond to a <presence> update by firing back with presence information
476 * on the entire wholist. Check this assumption, it's probably wrong.
478 xmpp_wholist_presence_dump();
481 else if ( (!strcasecmp(el, "body")) && (XMPP->html_tag_level == 0) ) {
482 if (XMPP->message_body != NULL) {
483 free(XMPP->message_body);
484 XMPP->message_body = NULL;
486 if (XMPP->chardata_len > 0) {
487 XMPP->message_body = strdup(XMPP->chardata);
491 else if (!strcasecmp(el, "message")) {
492 xmpp_send_message(XMPP->message_to, XMPP->message_body);
493 XMPP->html_tag_level = 0;
496 else if (!strcasecmp(el, "html")) {
497 --XMPP->html_tag_level;
500 else if (!strcasecmp(el, "starttls")) {
502 cprintf("<proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
503 CtdlModuleStartCryptoMsgs(NULL, NULL, NULL);
504 if (!CC->redirect_ssl) CC->kill_me = KILLME_NO_CRYPTO;
506 cprintf("<failure xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
507 CC->kill_me = KILLME_NO_CRYPTO;
511 else if (!strcasecmp(el, "ping")) {
512 XMPP->ping_requested = 1;
515 else if (!strcasecmp(el, "stream")) {
516 syslog(LOG_DEBUG, "xmpp: client shut down their stream");
517 xmpp_massacre_roster();
518 cprintf("</stream>\n");
519 CC->kill_me = KILLME_CLIENT_LOGGED_OUT;
522 else if (!strcasecmp(el, "query")) {
523 /* already processed , no further action needed here */
526 else if (!strcasecmp(el, "bind")) {
527 /* already processed , no further action needed here */
531 syslog(LOG_DEBUG, "xmpp: ignoring unknown tag <%s>", el);
534 XMPP->chardata_len = 0;
535 if (XMPP->chardata_alloc > 0) {
536 XMPP->chardata[0] = 0;
541 void xmpp_xml_chardata(void *data, const XML_Char *s, int len)
545 if (X->chardata_alloc == 0) {
546 X->chardata_alloc = SIZ;
547 X->chardata = malloc(X->chardata_alloc);
549 if ((X->chardata_len + len + 1) > X->chardata_alloc) {
550 X->chardata_alloc = X->chardata_len + len + 1024;
551 X->chardata = realloc(X->chardata, X->chardata_alloc);
553 memcpy(&X->chardata[X->chardata_len], s, len);
554 X->chardata_len += len;
555 X->chardata[X->chardata_len] = 0;
560 * This cleanup function blows away the temporary memory and files used by the XMPP service.
562 void xmpp_cleanup_function(void) {
564 /* Don't do this stuff if this is not a XMPP session! */
565 if (CC->h_command_function != xmpp_command_loop) return;
567 if (XMPP->chardata != NULL) {
568 free(XMPP->chardata);
569 XMPP->chardata = NULL;
570 XMPP->chardata_len = 0;
571 XMPP->chardata_alloc = 0;
572 if (XMPP->message_body != NULL) {
573 free(XMPP->message_body);
576 XML_ParserFree(XMPP->xp);
582 * Here's where our XMPP session begins its happy day.
584 void xmpp_greeting(void) {
585 client_set_inbound_buf(4);
586 strcpy(CC->cs_clientname, "XMPP session");
587 CC->session_specific_data = malloc(sizeof(citxmpp));
588 memset(XMPP, 0, sizeof(citxmpp));
589 XMPP->last_event_processed = queue_event_seq;
591 /* XMPP does not use a greeting, but we still have to initialize some things. */
593 XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
594 if (XMPP->xp == NULL) {
595 syslog(LOG_ERR, "xmpp: cannot create XML parser");
596 CC->kill_me = KILLME_XML_PARSER;
600 XML_SetElementHandler(XMPP->xp, xmpp_xml_start, xmpp_xml_end);
601 XML_SetCharacterDataHandler(XMPP->xp, xmpp_xml_chardata);
602 // XML_SetUserData(XMPP->xp, something...);
604 /* Prevent the "billion laughs" attack against expat by disabling
605 * internal entity expansion. With 2.x, forcibly stop the parser
606 * if an entity is declared - this is safer and a more obvious
607 * failure mode. With older versions, simply prevent expansion
608 * of such entities. */
609 #ifdef HAVE_XML_STOPPARSER
610 XML_SetEntityDeclHandler(XMPP->xp, xmpp_entity_declaration);
612 XML_SetDefaultHandler(XMPP->xp, NULL);
615 CC->can_receive_im = 1; /* This protocol is capable of receiving instant messages */
620 * Main command loop for XMPP sessions.
622 void xmpp_command_loop(void) {
624 StrBuf *stream_input = NewStrBuf();
627 rc = client_read_random_blob(stream_input, 30);
629 XML_Parse(XMPP->xp, ChrPtr(stream_input), rc, 0);
632 syslog(LOG_ERR, "xmpp: client disconnected: ending session.");
633 CC->kill_me = KILLME_CLIENT_DISCONNECTED;
635 FreeStrBuf(&stream_input);
640 * Async loop for XMPP sessions (handles the transmission of unsolicited stanzas)
642 void xmpp_async_loop(void) {
643 xmpp_process_events();
644 xmpp_output_incoming_messages();
649 * Login hook for XMPP sessions
651 void xmpp_login_hook(void) {
652 xmpp_queue_event(XMPP_EVT_LOGIN, CC->cs_inet_email);
657 * Logout hook for XMPP sessions
659 void xmpp_logout_hook(void) {
660 xmpp_queue_event(XMPP_EVT_LOGOUT, CC->cs_inet_email);
664 const char *CitadelServiceXMPP="XMPP";
665 extern void xmpp_cleanup_events(void);
666 CTDL_MODULE_INIT(xmpp)
669 CtdlRegisterServiceHook(CtdlGetConfigInt("c_xmpp_c2s_port"),
676 CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP, PRIO_STOP + 70);
677 CtdlRegisterSessionHook(xmpp_login_hook, EVT_LOGIN, PRIO_LOGIN + 90);
678 CtdlRegisterSessionHook(xmpp_logout_hook, EVT_LOGOUT, PRIO_LOGOUT + 90);
679 CtdlRegisterSessionHook(xmpp_login_hook, EVT_UNSTEALTH, PRIO_UNSTEALTH + 1);
680 CtdlRegisterSessionHook(xmpp_logout_hook, EVT_STEALTH, PRIO_STEALTH + 1);
681 CtdlRegisterCleanupHook(xmpp_cleanup_events);
685 /* return our module name for the log */