Harden the implementation of '--disable-web-security'

content/renderer/renderer_blink_platform_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/renderer_blink_platform_impl.h"
 
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/lazy_instance.h"
 #include "base/location.h"
@@ skipping 405 matching lines @@
     sudden_termination_disables_++;
     if (sudden_termination_disables_ != 1)
       return;
   }
 
   RenderThread* thread = RenderThread::Get();
   if (thread)  // NULL in unittests.
     thread->Send(new RenderProcessHostMsg_SuddenTerminationChanged(enabled));
 }
 
+bool RendererBlinkPlatformImpl::canGrantUniversalAccess() {
+  if (!GetContentClient()
+           ->renderer()
+           ->ShouldEnforceUniversalAccessRestrictions()) {
+    return true;
+  }
+  bool is_access_grantable = false;
+  if (RenderThread* thread = RenderThread::Get()) {

[esprehn, 2015/12/10 08:06:44]

how is it possible that this is null? I don;t think we can be here and not have
a RenderThread.

+    thread->Send(new RenderProcessHostMsg_GetUniversalAccessDisposition(

[Marshall, 2015/12/09 14:20:22]

Since the result of this sync IPC call is effectively static it might be better
to either (a) cache the result from a single call or (b) pass the
kDisableWebSecurity flag to the renderer process and check it there instead of
using an IPC.

[jochen (gone - plz use gerrit), 2015/12/10 15:39:32]

a compromised renderer can just not ask the browser

+        &is_access_grantable));
+  }
+  return is_access_grantable;
+}
+
 WebStorageNamespace* RendererBlinkPlatformImpl::createLocalStorageNamespace() {
   return new WebStorageNamespaceImpl();
 }
 
 
 //------------------------------------------------------------------------------
 
 WebIDBFactory* RendererBlinkPlatformImpl::idbFactory() {
   return web_idb_factory_.get();
 }
@@ skipping 852 matching lines @@
 //------------------------------------------------------------------------------
 
 void RendererBlinkPlatformImpl::MockBatteryStatusChangedForTesting(
     const blink::WebBatteryStatus& status) {
   if (!g_test_battery_status_listener)
     return;
   g_test_battery_status_listener->updateBatteryStatus(status);
 }
 
 }  // namespace content