diff -r 000000000000 -r 6474c204b198 dom/base/WindowNamedPropertiesHandler.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dom/base/WindowNamedPropertiesHandler.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,248 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 sw=2 et tw=78: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WindowNamedPropertiesHandler.h"
+#include "mozilla/dom/WindowBinding.h"
+#include "nsDOMClassInfo.h"
+#include "nsGlobalWindow.h"
+#include "nsHTMLDocument.h"
+#include "nsJSUtils.h"
+#include "xpcprivate.h"
+
+namespace mozilla {
+namespace dom {
+
+static bool
+ShouldExposeChildWindow(nsString& aNameBeingResolved, nsIDOMWindow *aChild)
+{
+  // If we're same-origin with the child, go ahead and expose it.
+  nsCOMPtr<nsIScriptObjectPrincipal> sop = do_QueryInterface(aChild);
+  NS_ENSURE_TRUE(sop, false);
+  if (nsContentUtils::GetSubjectPrincipal()->Equals(sop->GetPrincipal())) {
+    return true;
+  }
+
+  // If we're not same-origin, expose it _only_ if the name of the browsing
+  // context matches the 'name' attribute of the frame element in the parent.
+  // The motivations behind this heuristic are worth explaining here.
+  //
+  // Historically, all UAs supported global named access to any child browsing
+  // context (that is to say, window.dolske returns a child frame where either
+  // the "name" attribute on the frame element was set to "dolske", or where
+  // the child explicitly set window.name = "dolske").
+  //
+  // This is problematic because it allows possibly-malicious and unrelated
+  // cross-origin subframes to pollute the global namespace of their parent in
+  // unpredictable ways (see bug 860494). This is also problematic for browser
+  // engines like Servo that want to run cross-origin script on different
+  // threads.
+  //
+  // The naive solution here would be to filter out any cross-origin subframes
+  // obtained when doing named lookup in global scope. But that is unlikely to
+  // be web-compatible, since it will break named access for consumers that do
+  // <iframe name="dolske" src="http://cross-origin.com/sadtrombone.html"> and
+  // expect to be able to access the cross-origin subframe via named lookup on
+  // the global.
+  //
+  // The optimal behavior would be to do the following:
+  // (a) Look for any child browsing context with name="dolske".
+  // (b) If the result is cross-origin, null it out.
+  // (c) If we have null, look for a frame element whose 'name' attribute is
+  //     "dolske".
+  //
+  // Unfortunately, (c) would require some engineering effort to be performant
+  // in Gecko, and probably in other UAs as well. So we go with a simpler
+  // approximation of the above. This approximation will only break sites that
+  // rely on their cross-origin subframes setting window.name to a known value,
+  // which is unlikely to be very common. And while it does introduce a
+  // dependency on cross-origin state when doing global lookups, it doesn't
+  // allow the child to arbitrarily pollute the parent namespace, and requires
+  // cross-origin communication only in a limited set of cases that can be
+  // computed independently by the parent.
+  nsCOMPtr<nsPIDOMWindow> piWin = do_QueryInterface(aChild);
+  NS_ENSURE_TRUE(piWin, false);
+  Element* e = piWin->GetFrameElementInternal();
+  return e && e->AttrValueIs(kNameSpaceID_None, nsGkAtoms::name,
+                             aNameBeingResolved, eCaseMatters);
+}
+
+static nsGlobalWindow*
+GetWindowFromGlobal(JSObject* aGlobal)
+{
+  nsGlobalWindow* win;
+  if (NS_SUCCEEDED(UNWRAP_OBJECT(Window, aGlobal, win))) {
+    return win;
+  }
+  XPCWrappedNative* wrapper = XPCWrappedNative::Get(aGlobal);
+  nsCOMPtr<nsPIDOMWindow> piWin = do_QueryWrappedNative(wrapper);
+  MOZ_ASSERT(piWin);
+  return static_cast<nsGlobalWindow*>(piWin.get());
+}
+
+bool
+WindowNamedPropertiesHandler::getOwnPropDescriptor(JSContext* aCx,
+                                                   JS::Handle<JSObject*> aProxy,
+                                                   JS::Handle<jsid> aId,
+                                                   bool /* unused */,
+                                                   JS::MutableHandle<JSPropertyDescriptor> aDesc)
+{
+  if (!JSID_IS_STRING(aId)) {
+    // Nothing to do if we're resolving a non-string property.
+    return true;
+  }
+
+  JS::Rooted<JSObject*> global(aCx, JS_GetGlobalForObject(aCx, aProxy));
+  if (HasPropertyOnPrototype(aCx, aProxy, aId)) {
+    return true;
+  }
+
+  nsDependentJSString str(aId);
+
+  // Grab the DOM window.
+  nsGlobalWindow* win = GetWindowFromGlobal(global);
+  if (win->Length() > 0) {
+    nsCOMPtr<nsIDOMWindow> childWin = win->GetChildWindow(str);
+    if (childWin && ShouldExposeChildWindow(str, childWin)) {
+      // We found a subframe of the right name. Shadowing via |var foo| in
+      // global scope is still allowed, since |var| only looks up |own|
+      // properties. But unqualified shadowing will fail, per-spec.
+      JS::Rooted<JS::Value> v(aCx);
+      if (!WrapObject(aCx, childWin, &v)) {
+        return false;
+      }
+      aDesc.object().set(aProxy);
+      aDesc.value().set(v);
+      aDesc.setAttributes(JSPROP_ENUMERATE);
+      return true;
+    }
+  }
+
+  // The rest of this function is for HTML documents only.
+  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(win->GetExtantDoc());
+  if (!htmlDoc) {
+    return true;
+  }
+  nsHTMLDocument* document = static_cast<nsHTMLDocument*>(htmlDoc.get());
+
+  Element* element = document->GetElementById(str);
+  if (element) {
+    JS::Rooted<JS::Value> v(aCx);
+    if (!WrapObject(aCx, element, &v)) {
+      return false;
+    }
+    aDesc.object().set(aProxy);
+    aDesc.value().set(v);
+    aDesc.setAttributes(JSPROP_ENUMERATE);
+    return true;
+  }
+
+  nsWrapperCache* cache;
+  nsISupports* result = document->ResolveName(str, &cache);
+  if (!result) {
+    return true;
+  }
+
+  JS::Rooted<JS::Value> v(aCx);
+  if (!WrapObject(aCx, result, cache, nullptr, &v)) {
+    return false;
+  }
+  aDesc.object().set(aProxy);
+  aDesc.value().set(v);
+  aDesc.setAttributes(JSPROP_ENUMERATE);
+  return true;
+}
+
+bool
+WindowNamedPropertiesHandler::defineProperty(JSContext* aCx,
+                                             JS::Handle<JSObject*> aProxy,
+                                             JS::Handle<jsid> aId,
+                                             JS::MutableHandle<JSPropertyDescriptor> aDesc)
+{
+  ErrorResult rv;
+  rv.ThrowTypeError(MSG_DEFINEPROPERTY_ON_GSP);
+  rv.ReportTypeError(aCx);
+  return false;
+}
+
+bool
+WindowNamedPropertiesHandler::ownPropNames(JSContext* aCx,
+                                           JS::Handle<JSObject*> aProxy,
+                                           unsigned flags,
+                                           JS::AutoIdVector& aProps)
+{
+  // Grab the DOM window.
+  nsGlobalWindow* win = GetWindowFromGlobal(JS_GetGlobalForObject(aCx, aProxy));
+  nsTArray<nsString> names;
+  win->GetSupportedNames(names);
+  // Filter out the ones we wouldn't expose from getOwnPropertyDescriptor.
+  // We iterate backwards so we can remove things from the list easily.
+  for (size_t i = names.Length(); i > 0; ) {
+    --i; // Now we're pointing at the next name we want to look at
+    nsCOMPtr<nsIDOMWindow> childWin = win->GetChildWindow(names[i]);
+    if (!childWin || !ShouldExposeChildWindow(names[i], childWin)) {
+      names.RemoveElementAt(i);
+    }
+  }
+  if (!AppendNamedPropertyIds(aCx, aProxy, names, false, aProps)) {
+    return false;
+  }
+
+  names.Clear();
+  nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(win->GetExtantDoc());
+  if (!htmlDoc) {
+    return true;
+  }
+  nsHTMLDocument* document = static_cast<nsHTMLDocument*>(htmlDoc.get());
+  document->GetSupportedNames(flags, names);
+
+  JS::AutoIdVector docProps(aCx);
+  if (!AppendNamedPropertyIds(aCx, aProxy, names, false, docProps)) {
+    return false;
+  }
+
+  return js::AppendUnique(aCx, aProps, docProps);
+}
+
+bool
+WindowNamedPropertiesHandler::delete_(JSContext* aCx,
+                                      JS::Handle<JSObject*> aProxy,
+                                      JS::Handle<jsid> aId, bool* aBp)
+{
+  *aBp = false;
+  return true;
+}
+
+// static
+void
+WindowNamedPropertiesHandler::Install(JSContext* aCx,
+                                      JS::Handle<JSObject*> aProto)
+{
+  JS::Rooted<JSObject*> protoProto(aCx);
+  if (!::JS_GetPrototype(aCx, aProto, &protoProto)) {
+    return;
+  }
+
+  // Note: since the scope polluter proxy lives on the window's prototype
+  // chain, it needs a singleton type to avoid polluting type information
+  // for properties on the window.
+  JS::Rooted<JSObject*> gsp(aCx);
+  js::ProxyOptions options;
+  options.setSingleton(true);
+  gsp = js::NewProxyObject(aCx, WindowNamedPropertiesHandler::getInstance(),
+                           JS::NullHandleValue, protoProto,
+                           js::GetGlobalForObjectCrossCompartment(aProto),
+                           options);
+  if (!gsp) {
+    return;
+  }
+
+  // And then set the prototype of the interface prototype object to be the
+  // global scope polluter.
+  ::JS_SplicePrototype(aCx, aProto, gsp);
+}
+
+} // namespace dom
+} // namespace mozilla