Non-web-accessible extension URLs should not load in non-extension processes

chrome/renderer/extensions/resource_request_policy.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 "chrome/renderer/extensions/resource_request_policy.h"
 
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/stringprintf.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/api/icons/icons_handler.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_set.h"
 #include "chrome/common/extensions/manifest_url_handler.h"
 #include "chrome/common/extensions/web_accessible_resources_handler.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/common/page_transition_types.h"
 #include "extensions/common/constants.h"
 #include "googleurl/src/gurl.h"
 #include "third_party/WebKit/Source/Platform/chromium/public/WebString.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebConsoleMessage.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebDocument.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebFrame.h"
 
 namespace extensions {
 
+// This method does a security check whether chrome-extension:// URLs can be
+// requested by the renderer. Since this is in an untrusted process, the browser
+// has a similar check to enforce the policy, in case this process is exploited.
+// If you are changing this function, ensure equivalent checks are added to
+// extension_protocols.cc AllowExtensionResourceLoad.
+
 // static
 bool ResourceRequestPolicy::CanRequestResource(
     const GURL& resource_url,
     WebKit::WebFrame* frame,
     content::PageTransition transition_type,
     const ExtensionSet* loaded_extensions) {
   CHECK(resource_url.SchemeIs(extensions::kExtensionScheme));
 
   const Extension* extension =
       loaded_extensions->GetExtensionOrAppByURL(ExtensionURLInfo(resource_url));
@@ skipping 79 matching lines @@
     return false;
   }
 
   return true;
 }
 
 ResourceRequestPolicy::ResourceRequestPolicy() {
 }
 
 }  // namespace extensions