Fix for CVE-2014-3660

Issues related to the billion laugh entity expansion which happened to
escape the initial set of fixes

parser.c

@@ -130,6 +130,29 @@ xmlParserEntityCheck(xmlParserCtxtPtr ctxt, size_t size,
         return (0);
     if (ctxt->lastError.code == XML_ERR_ENTITY_LOOP)
         return (1);
+
+    /*
+     * This may look absurd but is needed to detect
+     * entities problems
+     */
+    if ((ent != NULL) && (ent->etype != XML_INTERNAL_PREDEFINED_ENTITY) &&
+	(ent->content != NULL) && (ent->checked == 0)) {
+	unsigned long oldnbent = ctxt->nbentities;
+	xmlChar *rep;
+
+	ent->checked = 1;
+
+	rep = xmlStringDecodeEntities(ctxt, ent->content,
+				  XML_SUBSTITUTE_REF, 0, 0, 0);
+
+	ent->checked = (ctxt->nbentities - oldnbent + 1) * 2;
+	if (rep != NULL) {
+	    if (xmlStrchr(rep, '<'))
+		ent->checked |= 1;
+	    xmlFree(rep);
+	    rep = NULL;
+	}
+    }
     if (replacement != 0) {
 	if (replacement < XML_MAX_TEXT_LENGTH)
 	    return(0);
@@ -189,8 +212,11 @@ xmlParserEntityCheck(xmlParserCtxtPtr ctxt, size_t size,
             return (0);
     } else {
         /*
-         * strange we got no data for checking just return
+         * strange we got no data for checking
          */
+	if (((ctxt->lastError.code != XML_ERR_UNDECLARED_ENTITY) &&
+	     (ctxt->lastError.code != XML_WAR_UNDECLARED_ENTITY)) ||
+	    (ctxt->nbentities <= 10000))
 	    return (0);
     }
     xmlFatalErr(ctxt, XML_ERR_ENTITY_LOOP, NULL);
@@ -2589,6 +2615,7 @@ xmlParserHandlePEReference(xmlParserCtxtPtr ctxt) {
 				      name, NULL);
 		    ctxt->valid = 0;
 		}
+		xmlParserEntityCheck(ctxt, 0, NULL, 0);
 	    } else if (ctxt->input->free != deallocblankswrapper) {
 		    input = xmlNewBlanksWrapperInputStream(ctxt, entity);
 		    if (xmlPushInput(ctxt, input) < 0)
@@ -2759,6 +2786,7 @@ xmlStringLenDecodeEntities(xmlParserCtxtPtr ctxt, const xmlChar *str, int len,
 	    if ((ctxt->lastError.code == XML_ERR_ENTITY_LOOP) ||
 	        (ctxt->lastError.code == XML_ERR_INTERNAL_ERROR))
 	        goto int_error;
+	    xmlParserEntityCheck(ctxt, 0, ent, 0);
 	    if (ent != NULL)
 	        ctxt->nbentities += ent->checked / 2;
 	    if ((ent != NULL) &&
@@ -2810,6 +2838,7 @@ xmlStringLenDecodeEntities(xmlParserCtxtPtr ctxt, const xmlChar *str, int len,
 	    ent = xmlParseStringPEReference(ctxt, &str);
 	    if (ctxt->lastError.code == XML_ERR_ENTITY_LOOP)
 	        goto int_error;
+	    xmlParserEntityCheck(ctxt, 0, ent, 0);
 	    if (ent != NULL)
 	        ctxt->nbentities += ent->checked / 2;
 	    if (ent != NULL) {
@@ -7312,6 +7341,7 @@ xmlParseReference(xmlParserCtxtPtr ctxt) {
 		   (ret != XML_WAR_UNDECLARED_ENTITY)) {
 	    xmlFatalErrMsgStr(ctxt, XML_ERR_UNDECLARED_ENTITY,
 		     "Entity '%s' failed to parse\n", ent->name);
+	    xmlParserEntityCheck(ctxt, 0, ent, 0);
 	} else if (list != NULL) {
 	    xmlFreeNodeList(list);
 	    list = NULL;
@@ -7418,7 +7448,7 @@ xmlParseReference(xmlParserCtxtPtr ctxt) {
 		/*
 		 * We are copying here, make sure there is no abuse
 		 */
-		ctxt->sizeentcopy += ent->length;
+		ctxt->sizeentcopy += ent->length + 5;
 		if (xmlParserEntityCheck(ctxt, 0, ent, ctxt->sizeentcopy))
 		    return;
 
@@ -7466,7 +7496,7 @@ xmlParseReference(xmlParserCtxtPtr ctxt) {
 		/*
 		 * We are copying here, make sure there is no abuse
 		 */
-		ctxt->sizeentcopy += ent->length;
+		ctxt->sizeentcopy += ent->length + 5;
 		if (xmlParserEntityCheck(ctxt, 0, ent, ctxt->sizeentcopy))
 		    return;
 
@@ -7652,6 +7682,7 @@ xmlParseEntityRef(xmlParserCtxtPtr ctxt) {
 		ctxt->sax->reference(ctxt->userData, name);
 	    }
 	}
+	xmlParserEntityCheck(ctxt, 0, ent, 0);
 	ctxt->valid = 0;
     }
 
@@ -7845,6 +7876,7 @@ xmlParseStringEntityRef(xmlParserCtxtPtr ctxt, const xmlChar ** str) {
 			  "Entity '%s' not defined\n",
 			  name);
 	}
+	xmlParserEntityCheck(ctxt, 0, ent, 0);
 	/* TODO ? check regressions ctxt->valid = 0; */
     }
 
@@ -8004,6 +8036,7 @@ xmlParsePEReference(xmlParserCtxtPtr ctxt)
 			  name, NULL);
 	    ctxt->valid = 0;
 	}
+	xmlParserEntityCheck(ctxt, 0, NULL, 0);
     } else {
 	/*
 	 * Internal checking in case the entity quest barfed
@@ -8243,6 +8276,7 @@ xmlParseStringPEReference(xmlParserCtxtPtr ctxt, const xmlChar **str) {
 			  name, NULL);
 	    ctxt->valid = 0;
 	}
+	xmlParserEntityCheck(ctxt, 0, NULL, 0);
     } else {
 	/*
 	 * Internal checking in case the entity quest barfed