Fixing the case where mixed content checking for insecure form submission in secure origins is brea…

Source/core/html/HTMLFormElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 485 matching lines @@
     m_pendingAutocompleteEventsQueue->enqueueEvent(event.release());
 }
 
 void HTMLFormElement::parseAttribute(const QualifiedName& name, const AtomicString& value)
 {
     if (name == actionAttr) {
         m_attributes.parseAction(value);
         // If the new action attribute is pointing to insecure "action" location from a secure page
         // it is marked as "passive" mixed content.
         KURL actionURL = document().completeURL(m_attributes.action().isEmpty() ? document().url().string() : m_attributes.action());
-        if (MixedContentChecker::isMixedContent(document().securityOrigin(), actionURL))
-            document().frame()->loader().mixedContentChecker()->canSubmitToInsecureForm(document().securityOrigin(), actionURL);
+        // Check if the DOM has a frame before checking mixed content (crbug/398066).

[jww, 2014/08/01 23:20:52]

It's clear that you're checking if the DOM has a frame from the code. Make this
comment more about the "why". Something like, "Blink needs to check if the DOM
has a frame because the mixed content checker assumes it has a frame. See bug
xxx."

[mhm, 2014/08/01 23:28:44]

Done.

+        if (document().frame()) {
+            if (MixedContentChecker::isMixedContent(document().securityOrigin(), actionURL))
+                document().frame()->loader().mixedContentChecker()->canSubmitToInsecureForm(document().securityOrigin(), actionURL);
+        }
     } else if (name == targetAttr)
         m_attributes.setTarget(value);
     else if (name == methodAttr)
         m_attributes.updateMethodType(value);
     else if (name == enctypeAttr)
         m_attributes.updateEncodingType(value);
     else if (name == accept_charsetAttr)
         m_attributes.setAcceptCharset(value);
     else if (name == onautocompleteAttr)
         setAttributeEventListener(EventTypeNames::autocomplete, createAttributeEventListener(this, name, value, eventParameterName()));
@@ skipping 309 matching lines @@
 }
 
 void HTMLFormElement::setDemoted(bool demoted)
 {
     if (demoted)
         UseCounter::count(document(), UseCounter::DemotedFormElement);
     m_wasDemoted = demoted;
 }
 
 } // namespace