Revert xmpp back to a working state
[citadel.git] / citadel / modules / xmpp / serv_xmpp.c
index 922288f695bed26f71e7f404d2c15d9da2042098..7986cb573fdb254de00bac8f1684f79cff2896e6 100644 (file)
@@ -1,8 +1,8 @@
 /*
  * 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"
 
+/* XML_StopParser is present in expat 2.x */
+#if XML_MAJOR_VERSION > 1
+#define HAVE_XML_STOPPARSER
+#endif
+
 struct xmpp_event *xmpp_queue = NULL;
 
+int XMPPSrvDebugEnable = 0;
+
+
+
+#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
+) {
+       XMPPM_syslog(LOG_WARNING, "Illegal entity declaration encountered; stopping parser.");
+       XML_StopParser(XMPP->xp, XML_FALSE);
+}
+#endif
+
+static inline int XMPP_GetUtf8SequenceLength(const char *CharS, const char *CharE)
+{
+       /* if this is is migrated to strbuf, remove this copy. */
+       int n = 0;
+        unsigned char test = (1<<7);
+
+       if ((*CharS & 0xC0) != 0xC0) 
+               return 1;
+
+       while ((n < 8) && 
+              ((test & ((unsigned char)*CharS)) != 0)) 
+       {
+               test = test >> 1;
+               n ++;
+       }
+       if ((n > 6) || ((CharE - CharS) < n))
+               n = 0;
+       return n;
+}
+
+
 /*
  * Given a source string and a target buffer, returns the string
  * properly escaped for insertion into an XML stream.  Returns a
@@ -69,8 +112,11 @@ struct xmpp_event *xmpp_queue = NULL;
 char *xmlesc(char *buf, char *str, int bufsiz)
 {
        char *ptr;
+       char *eiptr;
        unsigned char ch;
+       int inlen;
        int len = 0;
+       int IsUtf8Sequence;
 
        if (!buf) return(NULL);
        buf[0] = 0;
@@ -79,6 +125,9 @@ char *xmlesc(char *buf, char *str, int bufsiz)
                return(buf);
        }
 
+       inlen = strlen(str);
+       eiptr = str + inlen;
+
        for (ptr=str; *ptr; ptr++) {
                ch = *ptr;
                if (ch == '<') {
@@ -103,10 +152,25 @@ char *xmlesc(char *buf, char *str, int bufsiz)
                        buf[len] = 0;
                }
                else {
-                       char oct[10];
-                       sprintf(oct, "&#%o;", ch);
-                       strcpy(&buf[len], oct);
-                       len += strlen(oct);
+                       char oct[32];
+
+                       IsUtf8Sequence =  XMPP_GetUtf8SequenceLength(&buf[len], eiptr);
+                       if (IsUtf8Sequence)
+                       {
+                               while (IsUtf8Sequence > 0){
+                                       buf[len] = *ptr;
+                                       len ++;
+                                       if (--IsUtf8Sequence)
+                                               ptr++;
+                               }
+                               buf[len] = '\0';
+                       }
+                       else
+                       {
+                               sprintf(oct, "&#%o;", ch);
+                               strcpy(&buf[len], oct);
+                               len += strlen(oct);
+                       }
                }
                if ((len + 6) > bufsiz) {
                        return(buf);
@@ -142,13 +206,15 @@ void xmpp_stream_start(void *data, const char *supplied_el, const char **attr)
        /* The features of this stream are... */
        cprintf("<stream:features>");
 
-#ifdef HAVE_OPENSSL_XXXX_COMMENTED_OUT
-       /* TLS encryption (but only if it isn't already active) */
+       /*
+        * TLS encryption (but only if it isn't already active)
+        * / 
+#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 */
                xmpp_output_auth_mechs();
@@ -179,9 +245,9 @@ void xmpp_xml_start(void *data, const char *supplied_el, const char **attr) {
        }
 
        /*
-       CtdlLogPrintf(CTDL_DEBUG, "XMPP ELEMENT START: <%s>\n", el);
+       XMPP_syslog(LOG_DEBUG, "XMPP ELEMENT START: <%s>\n", el);
        for (i=0; attr[i] != NULL; i+=2) {
-               CtdlLogPrintf(CTDL_DEBUG, "                    Attribute '%s' = '%s'\n", attr[i], attr[i+1]);
+               XMPP_syslog(LOG_DEBUG, "                    Attribute '%s' = '%s'\n", attr[i], attr[i+1]);
        }
        uncomment for more verbosity */
 
@@ -251,9 +317,9 @@ void xmpp_xml_end(void *data, const char *supplied_el) {
        }
 
        /*
-       CtdlLogPrintf(CTDL_DEBUG, "XMPP ELEMENT END  : <%s>\n", el);
+       XMPP_syslog(LOG_DEBUG, "XMPP ELEMENT END  : <%s>\n", el);
        if (XMPP->chardata_len > 0) {
-               CtdlLogPrintf(CTDL_DEBUG, "          chardata: %s\n", XMPP->chardata);
+               XMPP_syslog(LOG_DEBUG, "          chardata: %s\n", XMPP->chardata);
        }
        uncomment for more verbosity */
 
@@ -314,9 +380,9 @@ void xmpp_xml_end(void *data, const char *supplied_el) {
                         * Unknown query ... return the XML equivalent of a blank stare
                         */
                        else {
-                               CtdlLogPrintf(CTDL_DEBUG,
-                                       "Unknown query <%s> - returning <service-unavailable/>\n",
-                                       el
+                               XMPP_syslog(LOG_DEBUG,
+                                           "Unknown query <%s> - returning <service-unavailable/>\n",
+                                           el
                                );
                                cprintf("<iq type=\"error\" id=\"%s\">", xmlesc(xmlbuf, XMPP->iq_id, sizeof xmlbuf));
                                cprintf("<error code=\"503\" type=\"cancel\">"
@@ -437,10 +503,10 @@ void xmpp_xml_end(void *data, const char *supplied_el) {
 #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
        }
 
@@ -449,14 +515,14 @@ void xmpp_xml_end(void *data, const char *supplied_el) {
        }
 
        else if (!strcasecmp(el, "stream")) {
-               CtdlLogPrintf(CTDL_DEBUG, "XMPP client shut down their stream\n");
+               XMPPM_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 {
-               CtdlLogPrintf(CTDL_DEBUG, "Ignoring unknown tag <%s>\n", el);
+               XMPP_syslog(LOG_DEBUG, "Ignoring unknown tag <%s>\n", el);
        }
 
        XMPP->chardata_len = 0;
@@ -521,8 +587,8 @@ void xmpp_greeting(void) {
 
        XMPP->xp = XML_ParserCreateNS("UTF-8", ':');
        if (XMPP->xp == NULL) {
-               CtdlLogPrintf(CTDL_ALERT, "Cannot create XML parser!\n");
-               CC->kill_me = 1;
+               XMPPM_syslog(LOG_ALERT, "Cannot create XML parser!\n");
+               CC->kill_me = KILLME_XML_PARSER;
                return;
        }
 
@@ -530,6 +596,17 @@ void xmpp_greeting(void) {
        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 */
 }
 
@@ -547,8 +624,8 @@ void xmpp_command_loop(void) {
                XML_Parse(XMPP->xp, ChrPtr(stream_input), rc, 0);
        }
        else {
-               CtdlLogPrintf(CTDL_ERR, "Client disconnected: ending session.\n");
-               CC->kill_me = 1;
+               XMPPM_syslog(LOG_ERR, "client disconnected: ending session.\n");
+               CC->kill_me = KILLME_CLIENT_DISCONNECTED;
        }
        FreeStrBuf(&stream_input);
 }
@@ -579,6 +656,10 @@ void xmpp_logout_hook(void) {
 }
 
 
+void LogXMPPSrvDebugEnable(const int n)
+{
+       XMPPSrvDebugEnable = n;
+}
 const char *CitadelServiceXMPP="XMPP";
 extern void xmpp_cleanup_events(void);
 CTDL_MODULE_INIT(xmpp)
@@ -591,15 +672,16 @@ CTDL_MODULE_INIT(xmpp)
                                        xmpp_async_loop,
                                        CitadelServiceXMPP
                );
-               CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP);
-                CtdlRegisterSessionHook(xmpp_login_hook, EVT_LOGIN);
-                CtdlRegisterSessionHook(xmpp_logout_hook, EVT_LOGOUT);
-                CtdlRegisterSessionHook(xmpp_login_hook, EVT_UNSTEALTH);
-                CtdlRegisterSessionHook(xmpp_logout_hook, EVT_STEALTH);
+               CtdlRegisterDebugFlagHook(HKEY("serv_xmpp"), LogXMPPSrvDebugEnable, &XMPPSrvDebugEnable);
+               CtdlRegisterSessionHook(xmpp_cleanup_function, EVT_STOP, PRIO_STOP + 70);
+                CtdlRegisterSessionHook(xmpp_login_hook, EVT_LOGIN, PRIO_LOGIN + 90);
+                CtdlRegisterSessionHook(xmpp_logout_hook, EVT_LOGOUT, PRIO_LOGOUT + 90);
+                CtdlRegisterSessionHook(xmpp_login_hook, EVT_UNSTEALTH, PRIO_UNSTEALTH + 1);
+                CtdlRegisterSessionHook(xmpp_logout_hook, EVT_STEALTH, PRIO_STEALTH + 1);
                CtdlRegisterCleanupHook(xmpp_cleanup_events);
 
        }
 
-       /* return our Subversion id for the Log */
+       /* return our module name for the log */
        return "xmpp";
 }