chrome/renderer/extensions/resource_request_policy.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/renderer/extensions/resource_request_policy.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/logging.h"
   9 #include "base/strings/stringprintf.h"
  10 #include "chrome/common/chrome_switches.h"
  11 #include "chrome/common/extensions/manifest_url_handler.h"
  12 #include "chrome/common/url_constants.h"
  13 #include "content/public/common/page_transition_types.h"
  14 #include "extensions/common/constants.h"
  15 #include "extensions/common/extension.h"
  16 #include "extensions/common/extension_set.h"
  17 #include "extensions/common/manifest_handlers/icons_handler.h"
  18 #include "extensions/common/manifest_handlers/web_accessible_resources_info.h"
  19 #include "third_party/WebKit/public/platform/WebString.h"
  20 #include "third_party/WebKit/public/web/WebConsoleMessage.h"
  21 #include "third_party/WebKit/public/web/WebDocument.h"
  22 #include "third_party/WebKit/public/web/WebFrame.h"
  23 #include "url/gurl.h"
  24
  25 namespace extensions {
  26
  27 // This method does a security check whether chrome-extension:// URLs can be
  28 // requested by the renderer. Since this is in an untrusted process, the browser
  29 // has a similar check to enforce the policy, in case this process is exploited.
  30 // If you are changing this function, ensure equivalent checks are added to
  31 // extension_protocols.cc's AllowExtensionResourceLoad.
  32
  33 // static
  34 bool ResourceRequestPolicy::CanRequestResource(
  35     const GURL& resource_url,
  36     blink::WebFrame* frame,
  37     content::PageTransition transition_type,
  38     const ExtensionSet* loaded_extensions) {
  39   CHECK(resource_url.SchemeIs(extensions::kExtensionScheme));
  40
  41   const Extension* extension =
  42       loaded_extensions->GetExtensionOrAppByURL(resource_url);
  43   if (!extension) {
  44     // Allow the load in the case of a non-existent extension. We'll just get a
  45     // 404 from the browser process.
  46     return true;
  47   }
  48
  49   // Disallow loading of packaged resources for hosted apps. We don't allow
  50   // hybrid hosted/packaged apps. The one exception is access to icons, since
  51   // some extensions want to be able to do things like create their own
  52   // launchers.
  53   std::string resource_root_relative_path =
  54       resource_url.path().empty() ? std::string()
  55                                   : resource_url.path().substr(1);
  56   if (extension->is_hosted_app() &&
  57       !IconsInfo::GetIcons(extension)
  58           .ContainsPath(resource_root_relative_path)) {
  59     LOG(ERROR) << "Denying load of " << resource_url.spec() << " from "
  60                << "hosted app.";
  61     return false;
  62   }
  63
  64   // Disallow loading of extension resources which are not explicitly listed
  65   // as web accessible if the manifest version is 2 or greater.
  66   if (!WebAccessibleResourcesInfo::IsResourceWebAccessible(
  67           extension, resource_url.path()) &&
  68       !CommandLine::ForCurrentProcess()->HasSwitch(
  69           switches::kDisableExtensionsResourceWhitelist)) {
  70     GURL frame_url = frame->document().url();
  71     GURL page_url = frame->top()->document().url();
  72
  73     // Exceptions are:
  74     // - empty origin (needed for some edge cases when we have empty origins)
  75     bool is_empty_origin = frame_url.is_empty();
  76     // - extensions requesting their own resources (frame_url check is for
  77     //     images, page_url check is for iframes)
  78     bool is_own_resource = frame_url.GetOrigin() == extension->url() ||
  79         page_url.GetOrigin() == extension->url();
  80     // - devtools (chrome-extension:// URLs are loaded into frames of devtools
  81     //     to support the devtools extension APIs)
  82     bool is_dev_tools = page_url.SchemeIs(content::kChromeDevToolsScheme) &&
  83                         !ManifestURL::GetDevToolsPage(extension).is_empty();
  84     bool transition_allowed =
  85         !content::PageTransitionIsWebTriggerable(transition_type);
  86     // - unreachable web page error page (to allow showing the icon of the
  87     //   unreachable app on this page)
  88     bool is_error_page = frame_url == GURL(content::kUnreachableWebDataURL);
  89
  90     if (!is_empty_origin && !is_own_resource &&
  91         !is_dev_tools && !transition_allowed && !is_error_page) {
  92       std::string message = base::StringPrintf(
  93           "Denying load of %s. Resources must be listed in the "
  94           "web_accessible_resources manifest key in order to be loaded by "
  95           "pages outside the extension.",
  96           resource_url.spec().c_str());
  97       frame->addMessageToConsole(
  98           blink::WebConsoleMessage(blink::WebConsoleMessage::LevelError,
  99                                     blink::WebString::fromUTF8(message)));
 100       return false;
 101     }
 102   }
 103
 104   return true;
 105 }
 106
 107 // static
 108 bool ResourceRequestPolicy::CanRequestExtensionResourceScheme(
 109     const GURL& resource_url,
 110     blink::WebFrame* frame) {
 111   CHECK(resource_url.SchemeIs(extensions::kExtensionResourceScheme));
 112
 113   GURL frame_url = frame->document().url();
 114   if (!frame_url.is_empty() &&
 115       !frame_url.SchemeIs(extensions::kExtensionScheme)) {
 116     std::string message = base::StringPrintf(
 117         "Denying load of %s. chrome-extension-resources:// can only be "
 118         "loaded from extensions.",
 119       resource_url.spec().c_str());
 120     frame->addMessageToConsole(
 121         blink::WebConsoleMessage(blink::WebConsoleMessage::LevelError,
 122                                   blink::WebString::fromUTF8(message)));
 123     return false;
 124   }
 125
 126   return true;
 127 }
 128
 129 ResourceRequestPolicy::ResourceRequestPolicy() {
 130 }
 131
 132 }  // namespace extensions