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/external_provider_impl.h"
  
  #include <set>
  #include <vector>
  
  #include "base/command_line.h"
  #include "base/files/file_path.h"
  #include "base/logging.h"
  #include "base/memory/linked_ptr.h"
  #include "base/metrics/field_trial.h"
  #include "base/path_service.h"
  #include "base/strings/string_util.h"
  #include "base/values.h"
  #include "base/version.h"
  #include "chrome/browser/app_mode/app_mode_utils.h"
  #include "chrome/browser/browser_process.h"
  #include "chrome/browser/extensions/extension_service.h"
  #include "chrome/browser/extensions/external_component_loader.h"
  #include "chrome/browser/extensions/external_policy_loader.h"
  #include "chrome/browser/extensions/external_pref_loader.h"
  #include "chrome/browser/profiles/profile.h"
  #include "chrome/common/chrome_paths.h"
  #include "chrome/common/chrome_switches.h"
  #include "chrome/common/pref_names.h"
  #include "components/crx_file/id_util.h"
  #include "content/public/browser/browser_thread.h"
  #include "extensions/browser/extension_system.h"
  #include "extensions/browser/external_provider_interface.h"
  #include "extensions/common/extension.h"
  #include "extensions/common/manifest.h"
  #include "ui/base/l10n/l10n_util.h"
  
  #if defined(OS_CHROMEOS)
  #include "chrome/browser/chromeos/app_mode/kiosk_app_manager.h"
  #include "chrome/browser/chromeos/customization_document.h"
  #include "chrome/browser/chromeos/extensions/device_local_account_external_policy_loader.h"
  #include "chrome/browser/chromeos/policy/app_pack_updater.h"
  #include "chrome/browser/chromeos/policy/browser_policy_connector_chromeos.h"
  #include "chrome/browser/chromeos/policy/device_local_account.h"
  #include "chrome/browser/chromeos/policy/device_local_account_policy_service.h"
  #include "chrome/browser/chromeos/profiles/profile_helper.h"
  #include "components/user_manager/user.h"
  #include "components/user_manager/user_manager.h"
  #else
  #include "chrome/browser/extensions/default_apps.h"
  #endif
  
  #if defined(OS_WIN)
  #include "chrome/browser/extensions/external_registry_loader_win.h"
  #endif
  
  using content::BrowserThread;
  
  namespace extensions {
  
  // Constants for keeping track of extension preferences in a dictionary.
  const char ExternalProviderImpl::kInstallParam[] = "install_parameter";
  const char ExternalProviderImpl::kExternalCrx[] = "external_crx";
  const char ExternalProviderImpl::kExternalVersion[] = "external_version";
  const char ExternalProviderImpl::kExternalUpdateUrl[] = "external_update_url";
  const char ExternalProviderImpl::kIsBookmarkApp[] = "is_bookmark_app";
  const char ExternalProviderImpl::kIsFromWebstore[] = "is_from_webstore";
  const char ExternalProviderImpl::kKeepIfPresent[] = "keep_if_present";
  const char ExternalProviderImpl::kWasInstalledByOem[] = "was_installed_by_oem";
  const char ExternalProviderImpl::kSupportedLocales[] = "supported_locales";
  const char ExternalProviderImpl::kMayBeUntrusted[] = "may_be_untrusted";
  
  ExternalProviderImpl::ExternalProviderImpl(
      VisitorInterface* service,
      const scoped_refptr<ExternalLoader>& loader,
      Profile* profile,
      Manifest::Location crx_location,
      Manifest::Location download_location,
      int creation_flags)
      : crx_location_(crx_location),
        download_location_(download_location),
        service_(service),
        ready_(false),
        loader_(loader),
        profile_(profile),
        creation_flags_(creation_flags),
        auto_acknowledge_(false) {
    loader_->Init(this);
  }
  
  ExternalProviderImpl::~ExternalProviderImpl() {
    CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
    loader_->OwnerShutdown();
  }
  
  void ExternalProviderImpl::VisitRegisteredExtension() {
    // The loader will call back to SetPrefs.
    loader_->StartLoading();
  }
  
  void ExternalProviderImpl::SetPrefs(base::DictionaryValue* prefs) {
    CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  
    // Check if the service is still alive. It is possible that it went
    // away while |loader_| was working on the FILE thread.
    if (!service_) return;
  
    prefs_.reset(prefs);
    ready_ = true;  // Queries for extensions are allowed from this point.
  
    // Set of unsupported extensions that need to be deleted from prefs_.
    std::set<std::string> unsupported_extensions;
  
    // Notify ExtensionService about all the extensions this provider has.
    for (base::DictionaryValue::Iterator i(*prefs_); !i.IsAtEnd(); i.Advance()) {
      const std::string& extension_id = i.key();
      const base::DictionaryValue* extension = NULL;
  
      if (!crx_file::id_util::IdIsValid(extension_id)) {
        LOG(WARNING) << "Malformed extension dictionary: key "
                     << extension_id.c_str() << " is not a valid id.";
        continue;
      }
  
      if (!i.value().GetAsDictionary(&extension)) {
        LOG(WARNING) << "Malformed extension dictionary: key "
                     << extension_id.c_str()
                     << " has a value that is not a dictionary.";
        continue;
      }
  
      base::FilePath::StringType external_crx;
      const base::Value* external_version_value = NULL;
      std::string external_version;
      std::string external_update_url;
  
      bool has_external_crx = extension->GetString(kExternalCrx, &external_crx);
  
      bool has_external_version = false;
      if (extension->Get(kExternalVersion, &external_version_value)) {
        if (external_version_value->IsType(base::Value::TYPE_STRING)) {
          external_version_value->GetAsString(&external_version);
          has_external_version = true;
        } else {
          LOG(WARNING) << "Malformed extension dictionary for extension: "
                       << extension_id.c_str() << ". " << kExternalVersion
                       << " value must be a string.";
          continue;
        }
      }
  
      bool has_external_update_url = extension->GetString(kExternalUpdateUrl,
                                                          &external_update_url);
      if (has_external_crx != has_external_version) {
        LOG(WARNING) << "Malformed extension dictionary for extension: "
                     << extension_id.c_str() << ".  " << kExternalCrx
                     << " and " << kExternalVersion << " must be used together.";
        continue;
      }
  
      if (has_external_crx == has_external_update_url) {
        LOG(WARNING) << "Malformed extension dictionary for extension: "
                     << extension_id.c_str() << ".  Exactly one of the "
                     << "followng keys should be used: " << kExternalCrx
                     << ", " << kExternalUpdateUrl << ".";
        continue;
      }
  
      // Check that extension supports current browser locale.
      const base::ListValue* supported_locales = NULL;
      if (extension->GetList(kSupportedLocales, &supported_locales)) {
        std::vector<std::string> browser_locales;
        l10n_util::GetParentLocales(g_browser_process->GetApplicationLocale(),
                                    &browser_locales);
  
        size_t num_locales = supported_locales->GetSize();
        bool locale_supported = false;
        for (size_t j = 0; j < num_locales; j++) {
          std::string current_locale;
          if (supported_locales->GetString(j, &current_locale) &&
              l10n_util::IsValidLocaleSyntax(current_locale)) {
            current_locale = l10n_util::NormalizeLocale(current_locale);
            if (std::find(browser_locales.begin(), browser_locales.end(),
                          current_locale) != browser_locales.end()) {
              locale_supported = true;
              break;
            }
          } else {
            LOG(WARNING) << "Unrecognized locale '" << current_locale
                         << "' found as supported locale for extension: "
                         << extension_id;
          }
        }
  
        if (!locale_supported) {
          unsupported_extensions.insert(extension_id);
          VLOG(1) << "Skip installing (or uninstall) external extension: "
                  << extension_id << " because the extension doesn't support "
                  << "the browser locale.";
          continue;
        }
      }
  
      int creation_flags = creation_flags_;
      bool is_bookmark_app;
      if (extension->GetBoolean(kIsBookmarkApp, &is_bookmark_app) &&
          is_bookmark_app) {
        creation_flags |= Extension::FROM_BOOKMARK;
      }
      bool is_from_webstore = false;
      if (extension->GetBoolean(kIsFromWebstore, &is_from_webstore) &&
          is_from_webstore) {
        creation_flags |= Extension::FROM_WEBSTORE;
      }
      bool keep_if_present = false;
      if (extension->GetBoolean(kKeepIfPresent, &keep_if_present) &&
          keep_if_present && profile_) {
        ExtensionServiceInterface* extension_service =
            ExtensionSystem::Get(profile_)->extension_service();
        const Extension* extension = extension_service ?
            extension_service->GetExtensionById(extension_id, true) : NULL;
        if (!extension) {
          VLOG(1) << "Skip installing (or uninstall) external extension: "
                  << extension_id << " because the extension should be kept "
                  << "only if it is already installed.";
          continue;
        }
      }
      bool was_installed_by_oem = false;
      if (extension->GetBoolean(kWasInstalledByOem, &was_installed_by_oem) &&
          was_installed_by_oem) {
        creation_flags |= Extension::WAS_INSTALLED_BY_OEM;
      }
      bool may_be_untrusted = false;
      if (extension->GetBoolean(kMayBeUntrusted, &may_be_untrusted) &&
          may_be_untrusted) {
        creation_flags |= Extension::MAY_BE_UNTRUSTED;
      }
  
      std::string install_parameter;
      extension->GetString(kInstallParam, &install_parameter);
  
      if (has_external_crx) {
        if (crx_location_ == Manifest::INVALID_LOCATION) {
          LOG(WARNING) << "This provider does not support installing external "
                       << "extensions from crx files.";
          continue;
        }
        if (external_crx.find(base::FilePath::kParentDirectory) !=
            base::StringPiece::npos) {
          LOG(WARNING) << "Path traversal not allowed in path: "
                       << external_crx.c_str();
          continue;
        }
  
        // If the path is relative, and the provider has a base path,
        // build the absolute path to the crx file.
        base::FilePath path(external_crx);
        if (!path.IsAbsolute()) {
          base::FilePath base_path = loader_->GetBaseCrxFilePath();
          if (base_path.empty()) {
            LOG(WARNING) << "File path " << external_crx.c_str()
                         << " is relative.  An absolute path is required.";
            continue;
          }
          path = base_path.Append(external_crx);
        }
  
        Version version(external_version);
        if (!version.IsValid()) {
          LOG(WARNING) << "Malformed extension dictionary for extension: "
                       << extension_id.c_str() << ".  Invalid version string \""
                       << external_version << "\".";
          continue;
        }
        service_->OnExternalExtensionFileFound(extension_id, &version, path,
                                               crx_location_, creation_flags,
                                               auto_acknowledge_);
      } else {  // if (has_external_update_url)
        CHECK(has_external_update_url);  // Checking of keys above ensures this.
        if (download_location_ == Manifest::INVALID_LOCATION) {
          LOG(WARNING) << "This provider does not support installing external "
                       << "extensions from update URLs.";
          continue;
        }
        GURL update_url(external_update_url);
        if (!update_url.is_valid()) {
          LOG(WARNING) << "Malformed extension dictionary for extension: "
                       << extension_id.c_str() << ".  Key " << kExternalUpdateUrl
                       << " has value \"" << external_update_url
                       << "\", which is not a valid URL.";
          continue;
        }
        service_->OnExternalExtensionUpdateUrlFound(extension_id,
                                                    install_parameter,
                                                    update_url,
                                                    download_location_,
                                                    creation_flags,
                                                    auto_acknowledge_);
      }
    }
  
    for (std::set<std::string>::iterator it = unsupported_extensions.begin();
         it != unsupported_extensions.end(); ++it) {
      // Remove extension for the list of know external extensions. The extension
      // will be uninstalled later because provider doesn't provide it anymore.
      prefs_->Remove(*it, NULL);
    }
  
    service_->OnExternalProviderReady(this);
  }
  
  void ExternalProviderImpl::ServiceShutdown() {
    service_ = NULL;
  }
  
  bool ExternalProviderImpl::IsReady() const {
    return ready_;
  }
  
  bool ExternalProviderImpl::HasExtension(
      const std::string& id) const {
    CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
    CHECK(prefs_.get());
    CHECK(ready_);
    return prefs_->HasKey(id);
  }
  
  bool ExternalProviderImpl::GetExtensionDetails(
      const std::string& id, Manifest::Location* location,
      scoped_ptr<Version>* version) const {
    CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
    CHECK(prefs_.get());
    CHECK(ready_);
    base::DictionaryValue* extension = NULL;
    if (!prefs_->GetDictionary(id, &extension))
      return false;
  
    Manifest::Location loc = Manifest::INVALID_LOCATION;
    if (extension->HasKey(kExternalUpdateUrl)) {
      loc = download_location_;
  
    } else if (extension->HasKey(kExternalCrx)) {
      loc = crx_location_;
  
      std::string external_version;
      if (!extension->GetString(kExternalVersion, &external_version))
        return false;
  
      if (version)
        version->reset(new Version(external_version));
  
    } else {
      NOTREACHED();  // Chrome should not allow prefs to get into this state.
      return false;
    }
  
    if (location)
      *location = loc;
  
    return true;
  }
  
  // static
  void ExternalProviderImpl::CreateExternalProviders(
      VisitorInterface* service,
      Profile* profile,
      ProviderCollection* provider_list) {
    scoped_refptr<ExternalLoader> external_loader;
    extensions::Manifest::Location crx_location = Manifest::INVALID_LOCATION;
  #if defined(OS_CHROMEOS)
    policy::BrowserPolicyConnectorChromeOS* connector =
        g_browser_process->platform_part()->browser_policy_connector_chromeos();
    bool is_chrome_os_public_session = false;
    const user_manager::User* user =
        chromeos::ProfileHelper::Get()->GetUserByProfile(profile);
    policy::DeviceLocalAccount::Type account_type;
    if (user && policy::IsDeviceLocalAccountUser(user->email(), &account_type)) {
      if (account_type == policy::DeviceLocalAccount::TYPE_PUBLIC_SESSION)
        is_chrome_os_public_session = true;
      policy::DeviceLocalAccountPolicyBroker* broker =
          connector->GetDeviceLocalAccountPolicyService()->GetBrokerForUser(
              user->email());
      if (broker) {
        external_loader = broker->extension_loader();
        crx_location = Manifest::EXTERNAL_POLICY;
      } else {
        NOTREACHED();
      }
    } else {
      external_loader = new ExternalPolicyLoader(profile);
    }
  #else
    external_loader = new ExternalPolicyLoader(profile);
  #endif
  
    // Policies are mandatory so they can't be skipped with command line flag.
    if (external_loader) {
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
              new ExternalProviderImpl(
                  service,
                  external_loader,
                  profile,
                  crx_location,
                  Manifest::EXTERNAL_POLICY_DOWNLOAD,
                  Extension::NO_FLAGS)));
    }
  
    // Load the KioskAppExternalProvider when running in kiosk mode.
    if (chrome::IsRunningInForcedAppMode()) {
  #if defined(OS_CHROMEOS)
      chromeos::KioskAppManager* kiosk_app_manager =
          chromeos::KioskAppManager::Get();
      DCHECK(kiosk_app_manager);
      if (kiosk_app_manager && !kiosk_app_manager->external_loader_created()) {
        provider_list->push_back(linked_ptr<ExternalProviderInterface>(
            new ExternalProviderImpl(service,
                                     kiosk_app_manager->CreateExternalLoader(),
                                     profile,
                                     Manifest::EXTERNAL_PREF,
                                     Manifest::INVALID_LOCATION,
                                     Extension::NO_FLAGS)));
      }
  #endif
      return;
    }
  
    // In tests don't install extensions from default external sources.
    // It would only slowdown tests and make them flaky.
    if (CommandLine::ForCurrentProcess()->HasSwitch(
        switches::kDisableDefaultApps))
      return;
  
    // On Mac OS, items in /Library/... should be written by the superuser.
    // Check that all components of the path are writable by root only.
    ExternalPrefLoader::Options check_admin_permissions_on_mac;
  #if defined(OS_MACOSX)
    check_admin_permissions_on_mac =
      ExternalPrefLoader::ENSURE_PATH_CONTROLLED_BY_ADMIN;
  #else
    check_admin_permissions_on_mac = ExternalPrefLoader::NONE;
  #endif
  
    bool is_chromeos_demo_session = false;
    int bundled_extension_creation_flags = Extension::NO_FLAGS;
  #if defined(OS_CHROMEOS)
    user_manager::UserManager* user_manager = user_manager::UserManager::Get();
    is_chromeos_demo_session =
        user_manager && user_manager->IsLoggedInAsDemoUser() &&
        connector->GetDeviceMode() == policy::DEVICE_MODE_RETAIL_KIOSK;
    bundled_extension_creation_flags = Extension::FROM_WEBSTORE |
        Extension::WAS_INSTALLED_BY_DEFAULT;
  #endif
  
  #if defined(OS_LINUX) && !defined(OS_CHROMEOS)
    if (!profile->IsSupervised()) {
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
              new ExternalProviderImpl(
                  service,
                  new ExternalPrefLoader(
                      chrome::DIR_STANDALONE_EXTERNAL_EXTENSIONS,
                      ExternalPrefLoader::NONE),
                  profile,
                  Manifest::EXTERNAL_PREF,
                  Manifest::EXTERNAL_PREF_DOWNLOAD,
                  bundled_extension_creation_flags)));
    }
  #endif
  
  #if defined(OS_CHROMEOS)
    if (!is_chromeos_demo_session && !is_chrome_os_public_session) {
      int external_apps_path_id = profile->IsSupervised() ?
          chrome::DIR_SUPERVISED_USERS_DEFAULT_APPS :
          chrome::DIR_STANDALONE_EXTERNAL_EXTENSIONS;
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(new ExternalProviderImpl(
              service,
              new ExternalPrefLoader(external_apps_path_id,
                                     ExternalPrefLoader::NONE),
              profile,
              Manifest::EXTERNAL_PREF,
              Manifest::EXTERNAL_PREF_DOWNLOAD,
              bundled_extension_creation_flags)));
  
      // OEM default apps.
      int oem_extension_creation_flags =
          bundled_extension_creation_flags | Extension::WAS_INSTALLED_BY_OEM;
      chromeos::ServicesCustomizationDocument* customization =
          chromeos::ServicesCustomizationDocument::GetInstance();
      provider_list->push_back(linked_ptr<ExternalProviderInterface>(
          new ExternalProviderImpl(service,
                                   customization->CreateExternalLoader(profile),
                                   profile,
                                   Manifest::EXTERNAL_PREF,
                                   Manifest::EXTERNAL_PREF_DOWNLOAD,
                                   oem_extension_creation_flags)));
    }
  
    policy::AppPackUpdater* app_pack_updater = connector->GetAppPackUpdater();
    if (is_chromeos_demo_session && app_pack_updater &&
        !app_pack_updater->created_external_loader()) {
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
            new ExternalProviderImpl(
                service,
                app_pack_updater->CreateExternalLoader(),
                profile,
                Manifest::EXTERNAL_PREF,
                Manifest::INVALID_LOCATION,
                Extension::NO_FLAGS)));
    }
  #endif
  
    if (!profile->IsSupervised() && !is_chromeos_demo_session) {
  #if !defined(OS_WIN)
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
              new ExternalProviderImpl(
                  service,
                  new ExternalPrefLoader(chrome::DIR_EXTERNAL_EXTENSIONS,
                                         check_admin_permissions_on_mac),
                  profile,
                  Manifest::EXTERNAL_PREF,
                  Manifest::EXTERNAL_PREF_DOWNLOAD,
                  bundled_extension_creation_flags)));
  #endif
  
      // Define a per-user source of external extensions.
  #if defined(OS_MACOSX)
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
              new ExternalProviderImpl(
                  service,
                  new ExternalPrefLoader(chrome::DIR_USER_EXTERNAL_EXTENSIONS,
                                         ExternalPrefLoader::NONE),
                  profile,
                  Manifest::EXTERNAL_PREF,
                  Manifest::EXTERNAL_PREF_DOWNLOAD,
                  Extension::NO_FLAGS)));
  #endif
  
  #if defined(OS_WIN)
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
              new ExternalProviderImpl(
                  service,
                  new ExternalRegistryLoader,
                  profile,
                  Manifest::EXTERNAL_REGISTRY,
                  Manifest::EXTERNAL_PREF_DOWNLOAD,
                  Extension::NO_FLAGS)));
  #endif
  
  #if !defined(OS_CHROMEOS)
      // The default apps are installed as INTERNAL but use the external
      // extension installer codeflow.
      provider_list->push_back(
          linked_ptr<ExternalProviderInterface>(
              new default_apps::Provider(
                  profile,
                  service,
                  new ExternalPrefLoader(chrome::DIR_DEFAULT_APPS,
                                         ExternalPrefLoader::NONE),
                  Manifest::INTERNAL,
                  Manifest::INTERNAL,
                  Extension::FROM_WEBSTORE |
                      Extension::WAS_INSTALLED_BY_DEFAULT)));
  #endif
  
      provider_list->push_back(
        linked_ptr<ExternalProviderInterface>(
          new ExternalProviderImpl(
              service,
              new ExternalComponentLoader(profile),
              profile,
              Manifest::INVALID_LOCATION,
              Manifest::EXTERNAL_COMPONENT,
              Extension::FROM_WEBSTORE | Extension::WAS_INSTALLED_BY_DEFAULT)));
    }
  }
  
  }  // namespace extensions
  