/*
* XMPP (Jabber) service for the Citadel system
- * Copyright (c) 2007-2010 by Art Cancro
+ * Copyright (c) 2007-2011 by Art Cancro
*
- * This program is free software; you can redistribute it and/or modify
+ * This program is open source software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
#include "ctdl_module.h"
#include "serv_xmpp.h"
+#if XML_MAJOR_VERSION > 0
+/* XML_StopParser is present in expat 2.x */
+#define HAVE_XML_STOPPARSER
+#endif
+
struct xmpp_event *xmpp_queue = NULL;
+
+
+#ifdef HAVE_XML_STOPPARSER
+/* Stop the parser if an entity declaration is hit. */
+static void xmpp_entity_declaration(void *userData, const XML_Char *entityName,
+ int is_parameter_entity, const XML_Char *value,
+ int value_length, const XML_Char *base,
+ const XML_Char *systemId, const XML_Char *publicId,
+ const XML_Char *notationName
+) {
+ syslog(LOG_WARNING, "Illegal entity declaration encountered; stopping parser.");
+ XML_StopParser(XMPP->xp, XML_FALSE);
+}
+#endif
+
+
+
/*
* Given a source string and a target buffer, returns the string
* properly escaped for insertion into an XML stream. Returns a
/*
* TLS encryption (but only if it isn't already active)
- *
- * NOTE: if TLS doesn't handshake properly for whatever reason,
- * comment out these three lines to disable it at the server.
- */
+ */
+#ifdef HAVE_OPENSSL
if (!CC->redirect_ssl) {
cprintf("<starttls xmlns='urn:ietf:params:xml:ns:xmpp-tls'></starttls>");
}
+#endif
if (!CC->logged_in) {
/* If we're not logged in yet, offer SASL as our feature set */
#ifdef HAVE_OPENSSL
cprintf("<proceed xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
CtdlModuleStartCryptoMsgs(NULL, NULL, NULL);
- if (!CC->redirect_ssl) CC->kill_me = 1;
+ if (!CC->redirect_ssl) CC->kill_me = KILLME_NO_CRYPTO;
#else
cprintf("<failure xmlns='urn:ietf:params:xml:ns:xmpp-tls'/>");
- CC->kill_me = 1;
+ CC->kill_me = KILLME_NO_CRYPTO;
#endif
}
syslog(LOG_DEBUG, "XMPP client shut down their stream\n");
xmpp_massacre_roster();
cprintf("</stream>\n");
- CC->kill_me = 1;
+ CC->kill_me = KILLME_CLIENT_LOGGED_OUT;
}
else {
XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
if (XMPP->xp == NULL) {
syslog(LOG_ALERT, "Cannot create XML parser!\n");
- CC->kill_me = 1;
+ CC->kill_me = KILLME_XML_PARSER;
return;
}
XML_SetCharacterDataHandler(XMPP->xp, xmpp_xml_chardata);
// XML_SetUserData(XMPP->xp, something...);
+ /* Prevent the "billion laughs" attack against expat by disabling
+ * internal entity expansion. With 2.x, forcibly stop the parser
+ * if an entity is declared - this is safer and a more obvious
+ * failure mode. With older versions, simply prevent expansion
+ * of such entities. */
+#ifdef HAVE_XML_STOPPARSER
+ XML_SetEntityDeclHandler(XMPP->xp, xmpp_entity_declaration);
+#else
+ XML_SetDefaultHandler(XMPP->xp, NULL);
+#endif
+
CC->can_receive_im = 1; /* This protocol is capable of receiving instant messages */
}
XML_Parse(XMPP->xp, ChrPtr(stream_input), rc, 0);
}
else {
- syslog(LOG_ERR, "Client disconnected: ending session.\n");
- CC->kill_me = 1;
+ syslog(LOG_ERR, "XMPP: client disconnected: ending session.\n");
+ CC->kill_me = KILLME_CLIENT_DISCONNECTED;
}
FreeStrBuf(&stream_input);
}
}
- /* return our Subversion id for the Log */
+ /* return our module name for the log */
return "xmpp";
}