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/extension_set.h"
12 #include "chrome/common/extensions/manifest_handlers/icons_handler.h"
13 #include "chrome/common/extensions/manifest_url_handler.h"
14 #include "chrome/common/extensions/web_accessible_resources_handler.h"
15 #include "chrome/common/url_constants.h"
16 #include "content/public/common/page_transition_types.h"
17 #include "extensions/common/constants.h"
18 #include "extensions/common/extension.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
CanRequestResource(const GURL & resource_url,blink::WebFrame * frame,content::PageTransition transition_type,const ExtensionSet * loaded_extensions)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(chrome::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
CanRequestExtensionResourceScheme(const GURL & resource_url,blink::WebFrame * frame)108 bool ResourceRequestPolicy::CanRequestExtensionResourceScheme(
109 const GURL& resource_url,
110 blink::WebFrame* frame) {
111 CHECK(resource_url.SchemeIs(chrome::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
ResourceRequestPolicy()129 ResourceRequestPolicy::ResourceRequestPolicy() {
130 }
131
132 } // namespace extensions
133