diff -u b/core/core.services.yml b/core/core.services.yml
--- b/core/core.services.yml
+++ b/core/core.services.yml
@@ -66,7 +66,7 @@
     arguments: ['@database', '@cache_tags.invalidator.checksum']
   cache.backend.apcu:
     class: Drupal\Core\Cache\ApcuBackendFactory
-    arguments: ['@app.root', '@kernel', '@cache_tags.invalidator.checksum']
+    arguments: ['@app.root', '@cache_tags.invalidator.checksum']
   cache.backend.php:
     class: Drupal\Core\Cache\PhpBackendFactory
     arguments: ['@cache_tags.invalidator.checksum']
@@ -136,7 +136,7 @@
     arguments: ['@database', '@cache_tags.invalidator.checksum']
   cache.backend.apcu:
     class: Drupal\Core\Cache\ApcuBackendFactory
-    arguments: ['@app.root', '@cache_tags.invalidator.checksum']
+    arguments: ['@app.root', '@site.path', '@cache_tags.invalidator.checksum']
   cache.backend.php:
     class: Drupal\Core\Cache\PhpBackendFactory
     arguments: ['@cache_tags.invalidator.checksum']
@@ -542,6 +542,16 @@
     class: Drupal\Core\AppRootFactory
     arguments: ['@kernel']
     public: false
+  site.path:
+    class: SplString
+    factory_service: 'site.path.factory'
+    factory_method: 'get'
+    tags:
+      - { name: parameter_service }
+  site.path.factory:
+    class: Drupal\Core\SitePathFactory
+    arguments: ['@kernel']
+    public: false
   controller_resolver:
     class: Drupal\Core\Controller\ControllerResolver
     arguments: ['@class_resolver']
diff -u b/core/includes/install.core.inc b/core/includes/install.core.inc
--- b/core/includes/install.core.inc
+++ b/core/includes/install.core.inc
@@ -1885,7 +1885,7 @@
   $readable = FALSE;
   $writable = FALSE;
   // @todo: Make this configurable.
-  $conf_path = \Drupal::service('kernel')->getSitePath();
+  $conf_path = \Drupal::service('site.path');
   $files_directory =  $conf_path . '/files';
   $translations_directory = $conf_path . '/files/translations';
   $translations_directory_exists = FALSE;
@@ -2065,7 +2065,7 @@
   foreach ($default_files as $default_file_info) {
     $readable = FALSE;
     $writable = FALSE;
-    $conf_path = './' . \Drupal::service('kernel')->getSitePath();
+    $conf_path = './' . \Drupal::service('site.path');
     $file = $conf_path . "/{$default_file_info['file']}";
     $default_file = "./sites/default/{$default_file_info['file_default']}";
     $exists = FALSE;
diff -u b/core/includes/install.inc b/core/includes/install.inc
--- b/core/includes/install.inc
+++ b/core/includes/install.inc
@@ -197,7 +197,7 @@
  */
 function drupal_rewrite_settings($settings = array(), $settings_file = NULL) {
   if (!isset($settings_file)) {
-    $settings_file = \Drupal::service('kernel')->getSitePath() . '/settings.php';
+    $settings_file = \Drupal::service('site.path') . '/settings.php';
   }
   // Build list of setting names and insert the values into the global namespace.
   $variable_names = array();
@@ -470,13 +470,13 @@
   $config_directories_hash = Crypt::randomBytesBase64(55);
   if (empty($config_directories[CONFIG_ACTIVE_DIRECTORY])) {
     $settings['config_directories'][CONFIG_ACTIVE_DIRECTORY] = (object) [
-      'value' => \Drupal::service('kernel')->getSitePath() . '/files/config_' . $config_directories_hash . '/active',
+      'value' => \Drupal::service('site.path') . '/files/config_' . $config_directories_hash . '/active',
       'required' => TRUE,
     ];
   }
   if (empty($config_directories[CONFIG_STAGING_DIRECTORY])) {
     $settings['config_directories'][CONFIG_STAGING_DIRECTORY] = (object) [
-      'value' => \Drupal::service('kernel')->getSitePath() . '/files/config_' . $config_directories_hash . '/staging',
+      'value' => \Drupal::service('site.path') . '/files/config_' . $config_directories_hash . '/staging',
       'required' => TRUE,
     ];
   }
diff -u b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php
--- b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php
+++ b/core/lib/Drupal/Core/Cache/ApcuBackendFactory.php
@@ -20,13 +20,6 @@
   protected $sitePrefix;
 
   /**
-   * The Drupal kernel.
-   *
-   * @var \Drupal\Core\DrupalKernelInterface
-   */
-  protected $kernel;
-
-  /**
    * The cache tags checksum provider.
    *
    * @var \Drupal\Core\Cache\CacheTagsChecksumInterface
@@ -38,13 +31,13 @@
    *
    * @param string $root
    *   The app root.
-   * @param \Drupal\Core\DrupalKernelInterface $kernel
-   *   The Drupal kernel.
+   * @param string $site_path
+   *   The site path.
    * @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
    *   The cache tags checksum provider.
    */
-  public function __construct($root, DrupalKernelInterface $kernel, CacheTagsChecksumInterface $checksum_provider) {
-    $this->sitePrefix = Crypt::hashBase64($root . '/' . $kernel->getSitePath());
+  public function __construct($root, $site_path, CacheTagsChecksumInterface $checksum_provider) {
+    $this->sitePrefix = Crypt::hashBase64($root . '/' . $site_path);
     $this->checksumProvider = $checksum_provider;
   }
 
diff -u b/core/lib/Drupal/Core/Database/Driver/sqlite/Install/Tasks.php b/core/lib/Drupal/Core/Database/Driver/sqlite/Install/Tasks.php
--- b/core/lib/Drupal/Core/Database/Driver/sqlite/Install/Tasks.php
+++ b/core/lib/Drupal/Core/Database/Driver/sqlite/Install/Tasks.php
@@ -49,7 +49,7 @@
     // Make the text more accurate for SQLite.
     $form['database']['#title'] = t('Database file');
     $form['database']['#description'] = t('The absolute path to the file where @drupal data will be stored. This must be writable by the web server and should exist outside of the web root.', array('@drupal' => drupal_install_profile_distribution_name()));
-    $default_database = \Drupal::service('kernel')->getSitePath() . '/files/.ht.sqlite';
+    $default_database = \Drupal::service('site.path') . '/files/.ht.sqlite';
     $form['database']['#default_value'] = empty($database['database']) ? $default_database : $database['database'];
     return $form;
   }
diff -u b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
--- b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
+++ b/core/lib/Drupal/Core/Extension/ExtensionDiscovery.php
@@ -157,7 +157,7 @@
     // Find the site-specific directory to search. Kernel service is not always
     // available at this point, but is preferred, when available.
     if (\Drupal::hasService('kernel')) {
-      $searchdirs[static::ORIGIN_SITE] = \Drupal::service('kernel')->getSitePath();
+      $searchdirs[static::ORIGIN_SITE] = \Drupal::service('site.path');
     }
     else {
       $searchdirs[static::ORIGIN_SITE] = DrupalKernel::findSitePath(Request::createFromGlobals());
diff -u b/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php b/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php
--- b/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php
+++ b/core/lib/Drupal/Core/Installer/Form/SiteConfigureForm.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\Core\Installer\Form;
 
-use Drupal\Core\DrupalKernelInterface;
 use Drupal\Core\Extension\ModuleInstallerInterface;
 use Drupal\Core\Form\ConfigFormBase;
 use Drupal\Core\Form\FormStateInterface;
@@ -22,11 +21,11 @@
 class SiteConfigureForm extends ConfigFormBase {
 
   /**
-   * The Drupal kernel.
+   * The site path.
    *
-   * @var \Drupal\Core\DrupalKernelInterface
+   * @var string
    */
-  protected $kernel;
+  protected $sitePath;
 
   /**
    * The user storage.
@@ -68,8 +67,8 @@
    *
    * @param string $root
    *   The app root.
-   * @param \Drupal\Core\DrupalKernelInterface $kernel
-   *   The Drupal kernel.
+   * @param string $site_path
+   *   The site path.
    * @param \Drupal\user\UserStorageInterface $user_storage
    *   The user storage.
    * @param \Drupal\Core\State\StateInterface $state
@@ -79,9 +78,9 @@
    * @param \Drupal\Core\Locale\CountryManagerInterface $country_manager
    *   The country manager.
    */
-  public function __construct($root, DrupalKernelInterface $kernel, UserStorageInterface $user_storage, StateInterface $state, ModuleInstallerInterface $module_installer, CountryManagerInterface $country_manager) {
+  public function __construct($root, $site_path, UserStorageInterface $user_storage, StateInterface $state, ModuleInstallerInterface $module_installer, CountryManagerInterface $country_manager) {
     $this->root = $root;
-    $this->kernel = $kernel;
+    $this->sitePath = $site_path;
     $this->userStorage = $user_storage;
     $this->state = $state;
     $this->moduleInstaller = $module_installer;
@@ -94,7 +93,7 @@
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('app.root'),
-      $container->get('kernel'),
+      $container->get('site.path'),
       $container->get('entity.manager')->getStorage('user'),
       $container->get('state'),
       $container->get('module_installer'),
@@ -127,7 +126,7 @@
     $form['#title'] = $this->t('Configure site');
 
     // Warn about settings.php permissions risk
-    $settings_dir = $this->kernel->getSitePath();
+    $settings_dir = $this->sitePath;
     $settings_file = $settings_dir . '/settings.php';
     // Check that $_POST is empty so we only show this message when the form is
     // first displayed, not on the next page after it is submitted. (We do not
diff -u b/core/lib/Drupal/Core/Installer/Form/SiteSettingsForm.php b/core/lib/Drupal/Core/Installer/Form/SiteSettingsForm.php
--- b/core/lib/Drupal/Core/Installer/Form/SiteSettingsForm.php
+++ b/core/lib/Drupal/Core/Installer/Form/SiteSettingsForm.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\Core\Installer\Form;
 
-use Drupal\Core\DrupalKernelInterface;
 use Drupal\Component\Utility\Crypt;
 use Drupal\Core\Database\Database;
 use Drupal\Core\Form\FormBase;
@@ -20,28 +19,28 @@
 class SiteSettingsForm extends FormBase {
 
   /**
-   * The Drupal kernel.
+   * The site path.
    *
-   * @var \Drupal\Core\DrupalKernelInterface
+   * @var string
    */
-  protected $kernel;
+  protected $sitePath;
 
   /**
    * Constructs a new SiteSettingsForm.
    *
-   * @param \Drupal\Core\DrupalKernelInterface $kernel
-   *   The Drupal kernel.
+   * @param string $site_path
+   *   The site path.
    */
-  public function __construct(DrupalKernelInterface $kernel) {
-    $this->kernel = $kernel;
-  }
+  public function __construct($site_path) {
+    $this->sitePath = $site_path;
+}
 
   /**
     * {@inheritdoc}
     */
   public static function create(ContainerInterface $container) {
     return new static(
-      $container->get('kernel')
+      $container->get('site.path')
     );
   }
 
@@ -56,7 +55,7 @@
    * {@inheritdoc}
    */
   public function buildForm(array $form, FormStateInterface $form_state) {
-    $conf_path = './' . $this->kernel->getSitePath();
+    $conf_path = './' . $this->sitePath;
     $settings_file = $conf_path . '/settings.php';
 
     $form['#title'] = $this->t('Database configuration');
diff -u b/core/lib/Drupal/Core/StreamWrapper/PublicStream.php b/core/lib/Drupal/Core/StreamWrapper/PublicStream.php
--- b/core/lib/Drupal/Core/StreamWrapper/PublicStream.php
+++ b/core/lib/Drupal/Core/StreamWrapper/PublicStream.php
@@ -66,7 +66,7 @@
     // Find the site path. Kernel service is not always available at this point,
     // but is preferred, when available.
     if (\Drupal::hasService('kernel')) {
-      $site_path = \Drupal::service('kernel')->getSitePath();
+      $site_path = \Drupal::service('site.path');
     }
     else {
       $site_path = DrupalKernel::findSitePath(Request::createFromGlobals());
diff -u b/core/modules/file/tests/file_test/src/StreamWrapper/DummyReadOnlyStreamWrapper.php b/core/modules/file/tests/file_test/src/StreamWrapper/DummyReadOnlyStreamWrapper.php
--- b/core/modules/file/tests/file_test/src/StreamWrapper/DummyReadOnlyStreamWrapper.php
+++ b/core/modules/file/tests/file_test/src/StreamWrapper/DummyReadOnlyStreamWrapper.php
@@ -31,7 +31,7 @@
   }
 
   function getDirectoryPath() {
-    return \Drupal::service('kernel')->getSitePath() . '/files';
+    return \Drupal::service('site.path') . '/files';
   }
 
   /**
diff -u b/core/modules/file/tests/file_test/src/StreamWrapper/DummyStreamWrapper.php b/core/modules/file/tests/file_test/src/StreamWrapper/DummyStreamWrapper.php
--- b/core/modules/file/tests/file_test/src/StreamWrapper/DummyStreamWrapper.php
+++ b/core/modules/file/tests/file_test/src/StreamWrapper/DummyStreamWrapper.php
@@ -31,7 +31,7 @@
   }
 
   function getDirectoryPath() {
-    return \Drupal::service('kernel')->getSitePath() . '/files';
+    return \Drupal::service('site.path') . '/files';
   }
 
   /**
diff -u b/core/modules/locale/locale.install b/core/modules/locale/locale.install
--- b/core/modules/locale/locale.install
+++ b/core/modules/locale/locale.install
@@ -15,7 +15,7 @@
 function locale_install() {
   // Create the interface translations directory and ensure it's writable.
   if (!$directory = \Drupal::config('locale.settings')->get('translation.path')) {
-    $conf_path = \Drupal::service('kernel')->getSitePath();
+    $conf_path = \Drupal::service('site.path');
     $directory = $conf_path . '/files/translations';
     \Drupal::configFactory()->getEditable('locale.settings')->set('translation.path', $directory)->save();
   }
diff -u b/core/modules/simpletest/src/TestBase.php b/core/modules/simpletest/src/TestBase.php
--- b/core/modules/simpletest/src/TestBase.php
+++ b/core/modules/simpletest/src/TestBase.php
@@ -1140,7 +1140,7 @@
     }
 
     // Backup current in-memory configuration.
-    $site_path = \Drupal::service('kernel')->getSitePath();
+    $site_path = \Drupal::service('site.path');
     $this->originalSite = $site_path;
     $this->originalSettings = Settings::getAll();
     $this->originalConfig = $GLOBALS['config'];
diff -u b/core/modules/system/src/Tests/File/DirectoryTest.php b/core/modules/system/src/Tests/File/DirectoryTest.php
--- b/core/modules/system/src/Tests/File/DirectoryTest.php
+++ b/core/modules/system/src/Tests/File/DirectoryTest.php
@@ -19,8 +19,8 @@
    * Test local directory handling functions.
    */
   function testFileCheckLocalDirectoryHandling() {
-    $kernel = $this->container->get('kernel');
-    $directory = $kernel->getSitePath() . '/files';
+    $site_path = $this->container->get('site.path');
+    $directory = $site_path . '/files';
 
     // Check a new recursively created local directory for correct file system
     // permissions.
diff -u b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php
--- b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php
+++ b/core/modules/system/src/Tests/File/ReadOnlyStreamWrapperTest.php
@@ -34,8 +34,8 @@
   function testReadOnlyBehavior() {
     // Generate a test file
     $filename = $this->randomMachineName();
-    $kernel = $this->container->get('kernel');
-    $filepath = $kernel->getSitePath() . '/files/' . $filename;
+    $site_path = $this->container->get('site.path');
+    $filepath = $site_path . '/files/' . $filename;
     file_put_contents($filepath, $filename);
 
     // Generate a read-only stream wrapper instance
@@ -80,7 +80,7 @@
 
     // Test the mkdir() function by attempting to create a directory.
     $dirname = $this->randomMachineName();
-    $dir = $kernel->getSitePath() . '/files/' . $dirname;
+    $dir = $site_path . '/files/' . $dirname;
     $readonlydir = $this->scheme . '://' . $dirname;
     $this->assertFalse(@drupal_mkdir($readonlydir, 0775, 0), 'Unable to create directory with read-only stream wrapper.');
     // Create a temporary directory for testing purposes
diff -u b/core/modules/system/src/Tests/Installer/InstallerExistingSettingsTest.php b/core/modules/system/src/Tests/Installer/InstallerExistingSettingsTest.php
--- b/core/modules/system/src/Tests/Installer/InstallerExistingSettingsTest.php
+++ b/core/modules/system/src/Tests/Installer/InstallerExistingSettingsTest.php
@@ -55,7 +55,7 @@
     // Find the site path. Kernel service is not always available at this point,
     // but is preferred, when available.
     if (\Drupal::hasService('kernel')) {
-      $conf_path = \Drupal::service('kernel')->getSitePath();
+      $conf_path = \Drupal::service('site.path');
     }
     else {
       $conf_path = DrupalKernel::findSitePath(Request::createFromGlobals());
diff -u b/core/modules/system/src/Tests/System/SettingsRewriteTest.php b/core/modules/system/src/Tests/System/SettingsRewriteTest.php
--- b/core/modules/system/src/Tests/System/SettingsRewriteTest.php
+++ b/core/modules/system/src/Tests/System/SettingsRewriteTest.php
@@ -21,7 +21,7 @@
    */
   function testDrupalRewriteSettings() {
     include_once \Drupal::root() . '/core/includes/install.inc';
-    $kernel = $this->container->get('kernel');
+    $site_path = $this->container->get('site.path');
     $tests = array(
       array(
         'original' => '$no_index_value_scalar = TRUE;',
@@ -100,7 +100,7 @@
       ),
     );
     foreach ($tests as $test) {
-      $filename = Settings::get('file_public_path', $kernel->getSitePath() . '/files') . '/mock_settings.php';
+      $filename = Settings::get('file_public_path', $site_path . '/files') . '/mock_settings.php';
       file_put_contents(\Drupal::root() . '/' . $filename, "<?php\n" . $test['original'] . "\n");
       drupal_rewrite_settings($test['settings'], $filename);
       $this->assertEqual(file_get_contents(\Drupal::root() . '/' . $filename), "<?php\n" . $test['expected'] . "\n");
@@ -118,7 +118,7 @@
       'expected' => '$no_index = true;'
     );
     // Make an empty file.
-    $filename = Settings::get('file_public_path', $kernel->getSitePath() . '/files') . '/mock_settings.php';
+    $filename = Settings::get('file_public_path', $site_path . '/files') . '/mock_settings.php';
     file_put_contents(\Drupal::root() . '/' . $filename, "");
 
     // Write the setting to the file.
diff -u b/core/modules/system/system.install b/core/modules/system/system.install
--- b/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -240,7 +240,7 @@
     // Find the site path. Kernel service is not always available at this point,
     // but is preferred, when available.
     if (\Drupal::hasService('kernel')) {
-      $conf_path = \Drupal::service('kernel')->getSitePath();
+      $conf_path = \Drupal::service('site.path');
     }
     else {
       $conf_path = DrupalKernel::findSitePath(Request::createFromGlobals());
diff -u b/core/modules/update/src/Form/UpdateManagerInstall.php b/core/modules/update/src/Form/UpdateManagerInstall.php
--- b/core/modules/update/src/Form/UpdateManagerInstall.php
+++ b/core/modules/update/src/Form/UpdateManagerInstall.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\update\Form;
 
-use Drupal\Core\DrupalKernelInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\FileTransfer\Local;
 use Drupal\Core\Form\FormBase;
@@ -35,11 +34,11 @@
   protected $root;
 
   /**
-   * The Drupal kernel.
+   * The site path.
    *
-   * @var \Drupal\Core\DrupalKernelInterface
+   * @var string
    */
-  protected $kernel;
+  protected $sitePath;
 
   /**
    * Constructs a new UpdateManagerInstall.
@@ -48,13 +47,13 @@
    *   The app root.
    * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler.
-   * @param \Drupal\Core\DrupalKernelInterface $kernel
-   *   The Drupal kernel.
+   * @param string $site_path
+   *   The site path.
    */
-  public function __construct($root, ModuleHandlerInterface $module_handler, DrupalKernelInterface $kernel) {
+  public function __construct($root, ModuleHandlerInterface $module_handler, $site_path) {
     $this->root = $root;
     $this->moduleHandler = $module_handler;
-    $this->kernel = $kernel;
+    $this->sitePath = $site_path;
   }
 
   /**
@@ -71,7 +70,7 @@
     return new static(
       $container->get('app.root'),
       $container->get('module_handler'),
-      $container->get('kernel')
+      $container->get('site.path')
     );
   }
 
@@ -228,7 +227,7 @@
     // install the code, there's no need to prompt for FTP/SSH credentials.
     // Instead, we instantiate a Drupal\Core\FileTransfer\Local and invoke
     // update_authorize_run_install() directly.
-    if (fileowner($project_real_location) == fileowner($this->kernel->getSitePath())) {
+    if (fileowner($project_real_location) == fileowner($this->sitePath)) {
       $this->moduleHandler->loadInclude('update', 'inc', 'update.authorize');
       $filetransfer = new Local($this->root);
       call_user_func_array('update_authorize_run_install', array_merge(array($filetransfer), $arguments));
diff -u b/core/modules/update/src/Form/UpdateReady.php b/core/modules/update/src/Form/UpdateReady.php
--- b/core/modules/update/src/Form/UpdateReady.php
+++ b/core/modules/update/src/Form/UpdateReady.php
@@ -7,7 +7,6 @@
 
 namespace Drupal\update\Form;
 
-use Drupal\Core\DrupalKernelInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\FileTransfer\Local;
 use Drupal\Core\Form\FormBase;
@@ -43,11 +42,11 @@
   protected $state;
 
   /**
-   * The Drupal kernel.
+   * The Site path.
    *
-   * @var \Drupal\Core\DrupalKernelInterface
+   * @var string
    */
-   protected $kernel;
+   protected $sitePath;
 
   /**
    * Constructs a new UpdateReady object.
@@ -58,14 +57,14 @@
    *   The object that manages enabled modules in a Drupal installation.
    * @param \Drupal\Core\State\StateInterface $state
    *   The state key value store.
-   * @param \Drupal\Core\DrupalKernelInterface $kernel
-   *   The Drupal kernel.
+   * @param string $site_path
+   *   The site path.
    */
-  public function __construct($root, ModuleHandlerInterface $module_handler, StateInterface $state, DrupalKernelInterface $kernel) {
+  public function __construct($root, ModuleHandlerInterface $module_handler, StateInterface $state, $site_path) {
     $this->root = $root;
     $this->moduleHandler = $module_handler;
     $this->state = $state;
-    $this->kernel = $kernel;
+    $this->sitePath = $site_path;
   }
 
   /**
@@ -83,7 +82,7 @@
       $container->get('app.root'),
       $container->get('module_handler'),
       $container->get('state'),
-      $container->get('kernel')
+      $container->get('site.path')
     );
   }
 
@@ -154,7 +153,7 @@
       // trying to install the code, there's no need to prompt for FTP/SSH
       // credentials. Instead, we instantiate a Drupal\Core\FileTransfer\Local
       // and invoke update_authorize_run_update() directly.
-      if (fileowner($project_real_location) == fileowner($this->kernel->getSitePath())) {
+      if (fileowner($project_real_location) == fileowner($this->sitePath)) {
         $this->moduleHandler->loadInclude('update', 'inc', 'update.authorize');
         $filetransfer = new Local($this->root);
         update_authorize_run_update($filetransfer, $updates);
diff -u b/core/modules/update/update.manager.inc b/core/modules/update/update.manager.inc
--- b/core/modules/update/update.manager.inc
+++ b/core/modules/update/update.manager.inc
@@ -306,7 +306,7 @@
   // the configuration directory to determine if local transfers will be
   // allowed.
   $temporary_file = drupal_tempnam('temporary://', 'update_');
-  $conf_path = \Drupal::service('kernel')->getSitePath();
+  $conf_path = \Drupal::service('site.path');
   $local_transfers_allowed = fileowner($temporary_file) === fileowner($conf_path);
 
   // Clean up. If this fails, we can ignore it (since this is just a temporary
only in patch2:
unchanged:
--- /dev/null
+++ b/core/lib/Drupal/Core/SitePathFactory.php
@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\SitePathFactory.
+ */
+
+namespace Drupal\Core;
+
+/**
+ * Gets the site path from the kernel.
+ */
+class SitePathFactory {
+
+  /**
+   * The Drupal kernel.
+   *
+   * @var \Drupal\Core\DrupalKernelInterface
+   */
+  protected $drupalKernel;
+
+  /**
+   * Constructs an SitePathFactory instance.
+   *
+   * @param \Drupal\Core\DrupalKernelInterface $drupal_kernel
+   *   The Drupal kernel.
+   */
+  public function __construct(DrupalKernelInterface $drupal_kernel) {
+    $this->drupalKernel = $drupal_kernel;
+  }
+
+  /**
+   * Gets the site path.
+   *
+   * @return string
+   *   The site path.
+   */
+  public function get() {
+    return $this->drupalKernel->getSitePath();
+  }
+
+}
+