text: // 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/browser/extensions/api/web_request/web_request_permissions.h"
  
  #include "base/strings/string_util.h"
  #include "base/strings/stringprintf.h"
  #include "chrome/browser/extensions/extension_renderer_state.h"
  #include "chrome/common/extensions/extension.h"
  #include "chrome/common/extensions/extension_constants.h"
  #include "chrome/common/extensions/permissions/permissions_data.h"
  #include "chrome/common/url_constants.h"
  #include "content/public/browser/resource_request_info.h"
  #include "extensions/browser/info_map.h"
  #include "extensions/common/constants.h"
  #include "net/url_request/url_request.h"
  #include "url/gurl.h"
  
  using content::ResourceRequestInfo;
  
  namespace {
  
  // Returns true if the URL is sensitive and requests to this URL must not be
  // modified/canceled by extensions, e.g. because it is targeted to the webstore
  // to check for updates, extension blacklisting, etc.
  bool IsSensitiveURL(const GURL& url) {
    // TODO(battre) Merge this, CanExtensionAccessURL and
    // PermissionsData::CanExecuteScriptOnPage into one function.
    bool sensitive_chrome_url = false;
    const std::string host = url.host();
    const char kGoogleCom[] = ".google.com";
    const char kClient[] = "clients";
    if (EndsWith(host, kGoogleCom, true)) {
      // Check for "clients[0-9]*.google.com" hosts.
      // This protects requests to several internal services such as sync,
      // extension update pings, captive portal detection, fraudulent certificate
      // reporting, autofill and others.
      if (StartsWithASCII(host, kClient, true)) {
        bool match = true;
        for (std::string::const_iterator i = host.begin() + strlen(kClient),
                 end = host.end() - strlen(kGoogleCom); i != end; ++i) {
          if (!isdigit(*i)) {
            match = false;
            break;
          }
        }
        sensitive_chrome_url = sensitive_chrome_url || match;
      }
      // This protects requests to safe browsing, link doctor, and possibly
      // others.
      sensitive_chrome_url = sensitive_chrome_url ||
          EndsWith(url.host(), ".clients.google.com", true) ||
          url.host() == "sb-ssl.google.com";
    }
    GURL::Replacements replacements;
    replacements.ClearQuery();
    replacements.ClearRef();
    GURL url_without_query = url.ReplaceComponents(replacements);
    return sensitive_chrome_url ||
        extension_urls::IsWebstoreUpdateUrl(url_without_query) ||
        extension_urls::IsBlacklistUpdateUrl(url);
  }
  
  // Returns true if the scheme is one we want to allow extensions to have access
  // to. Extensions still need specific permissions for a given URL, which is
  // covered by CanExtensionAccessURL.
  bool HasWebRequestScheme(const GURL& url) {
    return (url.SchemeIs(chrome::kAboutScheme) ||
            url.SchemeIs(chrome::kFileScheme) ||
            url.SchemeIs(chrome::kFileSystemScheme) ||
            url.SchemeIs(chrome::kFtpScheme) ||
            url.SchemeIs(content::kHttpScheme) ||
            url.SchemeIs(content::kHttpsScheme) ||
            url.SchemeIs(extensions::kExtensionScheme));
  }
  
  }  // namespace
  
  // static
  bool WebRequestPermissions::HideRequest(
      const extensions::InfoMap* extension_info_map,
      const net::URLRequest* request) {
    // Hide requests from the Chrome WebStore App or signin process.
    const ResourceRequestInfo* info = ResourceRequestInfo::ForRequest(request);
    if (info) {
      int process_id = info->GetChildID();
      int route_id = info->GetRouteID();
      ExtensionRendererState::WebViewInfo webview_info;
      // Never hide requests from guest processes.
      if (ExtensionRendererState::GetInstance()->GetWebViewInfo(
          process_id, route_id, &webview_info)) {
        return false;
      }
      if (extension_info_map && (
          extension_info_map->IsSigninProcess(process_id) ||
          extension_info_map->process_map().Contains(
              extension_misc::kWebStoreAppId, process_id))) {
        return true;
      }
    }
  
    const GURL& url = request->url();
    return IsSensitiveURL(url) || !HasWebRequestScheme(url);
  }
  
  // static
  bool WebRequestPermissions::CanExtensionAccessURL(
      const extensions::InfoMap* extension_info_map,
      const std::string& extension_id,
      const GURL& url,
      bool crosses_incognito,
      HostPermissionsCheck host_permissions_check) {
    // extension_info_map can be NULL in testing.
    if (!extension_info_map)
      return true;
  
    const extensions::Extension* extension =
        extension_info_map->extensions().GetByID(extension_id);
    if (!extension)
      return false;
  
    // Check if this event crosses incognito boundaries when it shouldn't.
    if (crosses_incognito && !extension_info_map->CanCrossIncognito(extension))
      return false;
  
    switch (host_permissions_check) {
      case DO_NOT_CHECK_HOST:
        break;
      case REQUIRE_HOST_PERMISSION:
        // about: URLs are not covered in host permissions, but are allowed
        // anyway.
        if (!((url.SchemeIs(chrome::kAboutScheme) ||
               extensions::PermissionsData::HasHostPermission(extension, url) ||
               url.GetOrigin() == extension->url()))) {
          return false;
        }
        break;
      case REQUIRE_ALL_URLS:
        if (!extensions::PermissionsData::HasEffectiveAccessToAllHosts(extension))
          return false;
        break;
    }
  
    return true;
  }
  