The security check in document.write should test for same-origin

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 3141 matching lines @@
   }
 
   if (m_throwOnDynamicMarkupInsertionCount) {
     exceptionState.throwDOMException(
         InvalidStateError,
         "Custom Element constructor should not use write().");
     return;
   }
 
   if (enteredDocument &&
-      !getSecurityOrigin()->canAccess(enteredDocument->getSecurityOrigin())) {
+      !getSecurityOrigin()->isSameSchemeHostPortAndSuborigin(
+          enteredDocument->getSecurityOrigin())) {
     exceptionState.throwSecurityError(
         "Can only call write() on same-origin documents.");
     return;
   }
 
   NestingLevelIncrementer nestingLevelIncrementer(m_writeRecursionDepth);
 
   m_writeRecursionIsTooDeep =
       (m_writeRecursionDepth > 1) && m_writeRecursionIsTooDeep;
   m_writeRecursionIsTooDeep =
@@ skipping 3443 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (blink::Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif