Move securityCheck out of V8WrapperInstantiationScope

third_party/WebKit/Source/bindings/core/v8/BindingSecurity.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * 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 14 matching lines @@
  * 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.
  */
 
 #include "bindings/core/v8/BindingSecurity.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/V8Binding.h"
+#include "bindings/core/v8/V8Location.h"
+#include "bindings/core/v8/WrapperCreationSecurityCheck.h"
 #include "core/dom/Document.h"
 #include "core/frame/LocalDOMWindow.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Location.h"
 #include "core/frame/Settings.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/workers/MainThreadWorkletGlobalScope.h"
 #include "platform/weborigin/SecurityOrigin.h"
 
 namespace blink {
@@ skipping 200 matching lines @@
     return false;
 
   // Note that there is no need to call back
   // FrameLoader::didAccessInitialDocument() because |targetWindow| must be
   // a child window inside iframe or frame and it doesn't have a URL bar,
   // so there is no need to worry about URL spoofing.
 
   return true;
 }
 
+void BindingSecurity::wrapperCreationSecurityCheck(
+    v8::Isolate* isolate,
+    v8::Local<v8::Context> creationContext,
+    const WrapperTypeInfo* type,
+    v8::Local<v8::Value> crossContextException) {
+  ExceptionState exceptionState(isolate, ExceptionState::ConstructionContext,
+                                type->interfaceName);
+
+  // According to
+  // https://html.spec.whatwg.org/multipage/browsers.html#security-location,
+  // cross-origin script access to a few properties of Location is allowed.
+  // Location already implements the necessary security checks.
+  if (type->equals(&V8Location::wrapperTypeInfo)) {
+    if (crossContextException.IsEmpty())

[Yuki, 2017/04/03 08:29:26]

I meant that we can do an early-exit at the beginning.

void BindingSecurity::wrapperCreationSecurityCheck(...) {
  if (crossContextException.IsEmpty())
    return;

  ExceptionState exceptionState(...);
  ...
}

However, now I think that it's better to do this early-exit on the call site. 
See my reply at:
https://codereview.chromium.org/2745313003/diff/120001/third_party/WebKit/Sou...

Given that we do the early-exit on the call site, we can write:

void BindingSecurity::wrapperCreationSecurityCheck(...) {
  DCHECK(!crossContextException.IsEmpty());

  ...
}

And then, I think that the expected behavior of this function will be "rethrow
an exception", and I'd prefer "rethrowCrossContextException" or something.  It's
a bit strange that fooCheck() returns void.

[adithyas, 2017/04/03 15:20:54]

Based on my reply on your earlier comment, I was thinking this could be 2
functions instead:

bool BindingSecurity::checkCreationContextAccess(creationContext, type) {
  if (type == V8Location)
    return true;
  frame = toLocalFrameIfNotDetached(creationContext)
  if (!frame) {
    return shouldAllowAccessToDetachedWindow(...); // could throw security error
  } else {
    return shouldAllowAccessToFrame(...); // could throw security error
  }
}

void BindingSecurity::rethrowCrossContextException(crossContextException, type,
creationContext) {
  if (type == V8Location) {
    // convert to security error and throw
  } else {
    // rethrow crossContextException
}

+      return;
+    // Convert cross-context exception to security error
+    LocalDOMWindow* callingWindow = currentDOMWindow(isolate);
+    LocalDOMWindow* targetWindow = toLocalDOMWindow(creationContext);
+    exceptionState.throwSecurityError(
+        targetWindow->sanitizedCrossDomainAccessErrorMessage(callingWindow),
+        targetWindow->crossDomainAccessErrorMessage(callingWindow));
+    return;
+  }
+
+  bool hasAccess = false;
+  LocalFrame* frame = toLocalFrameIfNotDetached(creationContext);
+
+  if (!frame) {
+    // Sandbox detached frames - they can't create cross origin objects.
+    LocalDOMWindow* callingWindow = currentDOMWindow(isolate);
+    LocalDOMWindow* targetWindow = toLocalDOMWindow(creationContext);
+
+    hasAccess = shouldAllowAccessToDetachedWindow(callingWindow, targetWindow,
+                                                  exceptionState);
+  } else {
+    const DOMWrapperWorld& currentWorld =
+        DOMWrapperWorld::world(isolate->GetCurrentContext());
+    CHECK_EQ(currentWorld.worldId(),
+             DOMWrapperWorld::world(creationContext).worldId());
+
+    hasAccess = !currentWorld.isMainWorld() ||
+                shouldAllowAccessToFrame(currentDOMWindow(isolate), frame,
+                                         exceptionState);
+  }
+
+  if (hasAccess && !crossContextException.IsEmpty()) {
+    exceptionState.rethrowV8Exception(crossContextException);
+  }

[Yuki, 2017/04/03 08:29:26]

You may want:
  DCHECK(exceptionState.hadException());

+}
+
 void BindingSecurity::failedAccessCheckFor(v8::Isolate* isolate,
                                            const Frame* target) {
   // TODO(dcheng): See if this null check can be removed or hoisted to a
   // different location.
   if (!target)
     return;
 
   DOMWindow* targetWindow = target->domWindow();
 
   // TODO(dcheng): Add ContextType, interface name, and property name as
   // arguments, so the generated exception can be more descriptive.
   ExceptionState exceptionState(isolate, ExceptionState::UnknownContext,
                                 nullptr, nullptr);
   exceptionState.throwSecurityError(
       targetWindow->sanitizedCrossDomainAccessErrorMessage(
           currentDOMWindow(isolate)),
       targetWindow->crossDomainAccessErrorMessage(currentDOMWindow(isolate)));
 }
 
 }  // namespace blink