Add access checks to V8WrapperInstationScope.

Source/bindings/core/v8/V8DOMWrapper.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
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  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef V8DOMWrapper_h
 #define V8DOMWrapper_h
 
+#include "bindings/core/v8/BindingSecurity.h"
 #include "bindings/core/v8/DOMDataStore.h"
 #include "bindings/core/v8/ScriptWrappable.h"
+#include "bindings/core/v8/V8Binding.h"
 #include "wtf/PassRefPtr.h"
 #include "wtf/RawPtr.h"
 #include "wtf/text/AtomicString.h"
 #include <v8.h>
 
 namespace blink {
 
 class Node;
 struct WrapperTypeInfo;
 
@@ skipping 53 matching lines @@
         wrapperTypeInfo->refObject(ScriptWrappable::fromNode(node));
         setNativeInfo(wrapper, wrapperTypeInfo, ScriptWrappable::fromNode(node));
         ASSERT(hasInternalFieldsSet(wrapper));
     }
     RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(toScriptWrappable(wrapper) == ScriptWrappable::fromNode(node));
     return wrapper;
 }
 
 class V8WrapperInstantiationScope {
 public:
-    V8WrapperInstantiationScope(v8::Local<v8::Object> creationContext, v8::Isolate* isolate)
+    V8WrapperInstantiationScope(v8::Local<v8::Object> creationContext, v8::Isolate* isolate, bool withSecurityCheck = true)

[Yuki, 2015/07/30 11:00:54]

The style guide recommends an enum value.
https://www.chromium.org/blink/coding-style#TOC-Names
See 10th rule.

         : m_didEnterContext(false)
         , m_context(isolate->GetCurrentContext())
     {
         // creationContext should not be empty. Because if we have an
         // empty creationContext, we will end up creating
         // a new object in the context currently entered. This is wrong.
         RELEASE_ASSERT(!creationContext.IsEmpty());
         v8::Local<v8::Context> contextForWrapper = creationContext->CreationContext();
         // For performance, we enter the context only if the currently running context
         // is different from the context that we are about to enter.
         if (contextForWrapper == m_context)
             return;
+        if (withSecurityCheck) {

[haraken, 2015/07/30 10:43:36]

Would you help me understand why we want to enable the check only for Location?
Given that this is a slow path, I guess it would be better to enable the
security check for all objects.

+            // If the context is different, we need to make sure that the current
+            // context has access to the creation context.
+            if (!m_context.IsEmpty()) {

[haraken, 2015/07/30 10:43:36]

m_context shouldn't be empty here.

+                Frame* frame = toFrameIfNotDetached(contextForWrapper);
+                RELEASE_ASSERT(!frame || BindingSecurity::shouldAllowAccessToFrame(isolate, frame, DoNotReportSecurityError));

[haraken, 2015/07/30 10:43:36]

Just to confirm: This will allow a wrapper creation on a cross-origin frame that
is already detached, but is it an expected behavior?

c.f., shouldAllowAccessToFrame() returns false for a null frame.

+            }
+        }
         m_context = v8::Local<v8::Context>::New(isolate, contextForWrapper);
         m_didEnterContext = true;
         m_context->Enter();
     }
 
     ~V8WrapperInstantiationScope()
     {
         if (!m_didEnterContext)
             return;
         m_context->Exit();
     }
 
     v8::Local<v8::Context> context() const { return m_context; }
 
 private:
     bool m_didEnterContext;
     v8::Local<v8::Context> m_context;
 };
 
 } // namespace blink
 
 #endif // V8DOMWrapper_h