Fix handling of large xml documents

Source/core/xml/parser/XMLDocumentParser.cpp

 /*
  * Copyright (C) 2000 Peter Kelly (pmk@post.com)
  * Copyright (C) 2005, 2006, 2008, 2014 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2007 Samuel Weinig (sam@webkit.org)
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008 Holger Hans Peter Freyther
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 716 matching lines @@
     xmlRegisterOutputCallbacks(matchFunc, openFunc, writeFunc, closeFunc);
     libxmlLoaderThread = currentThread();
     didInit = true;
 }
 
 
 PassRefPtr<XMLParserContext> XMLParserContext::createStringParser(xmlSAXHandlerPtr handlers, void* userData)
 {
     initializeLibXMLIfNecessary();
     xmlParserCtxtPtr parser = xmlCreatePushParserCtxt(handlers, 0, 0, 0, 0);
+    xmlCtxtUseOptions(parser, XML_PARSE_HUGE);
     parser->_private = userData;
     parser->replaceEntities = true;
     return adoptRef(new XMLParserContext(parser));
 }
 
 // Chunk should be encoded in UTF-8
 PassRefPtr<XMLParserContext> XMLParserContext::createMemoryParser(xmlSAXHandlerPtr handlers, void* userData, const CString& chunk)
 {
     initializeLibXMLIfNecessary();
 
     // appendFragmentSource() checks that the length doesn't overflow an int.
     xmlParserCtxtPtr parser = xmlCreateMemoryParserCtxt(chunk.data(), chunk.length());
 
     if (!parser)
         return nullptr;
 
     // Copy the sax handler
     memcpy(parser->sax, handlers, sizeof(xmlSAXHandler));
 
     // Set parser options.
     // XML_PARSE_NODICT: default dictionary option.
     // XML_PARSE_NOENT: force entities substitutions.
-    xmlCtxtUseOptions(parser, XML_PARSE_NODICT | XML_PARSE_NOENT);
+    // XML_PARSE_HUGE: don't impose arbitrary limits on document size.
+    xmlCtxtUseOptions(parser, XML_PARSE_NODICT | XML_PARSE_NOENT | XML_PARSE_HUGE);
 
     // Internal initialization
     parser->sax2 = 1;
     parser->instate = XML_PARSER_CONTENT; // We are parsing a CONTENT
     parser->depth = 0;
     parser->str_xml = xmlDictLookup(parser->dict, BAD_CAST "xml", 3);
     parser->str_xmlns = xmlDictLookup(parser->dict, BAD_CAST "xmlns", 5);
     parser->str_xml_ns = xmlDictLookup(parser->dict, XML_XML_NAMESPACE, 36);
     parser->_private = userData;
 
@@ skipping 912 matching lines @@
     sax.initialized = XML_SAX2_MAGIC;
     RefPtr<XMLParserContext> parser = XMLParserContext::createStringParser(&sax, &state);
     String parseString = "<?xml version=\"1.0\"?><attrs " + string + " />";
     parseChunk(parser->context(), parseString);
     finishParsing(parser->context());
     attrsOK = state.gotAttributes;
     return state.attributes;
 }
 
 } // namespace blink