Issue #1232572 by deviantintegral, joachim, cweagans, kenorb, bleen, webflo, ceng, Elijah Lynn, sriharsha.uppuluri: Add a variable to disable fixing file permissions in drupal_install_fix_file()

core/modules/system/src/Tests/System/SitesDirectoryHardeningTest.php

@@ -0,0 +1,115 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\system\Tests\System\SitesDirectoryHardeningTest.
+ */
+
+namespace Drupal\system\Tests\System;
+
+use Drupal\Component\Render\FormattableMarkup;
+use Drupal\Core\Site\Settings;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+use Drupal\simpletest\WebTestBase;
+
+/**
+ * Tests Drupal permissions hardening of /sites subdirectories.
+ *
+ * @group system
+ */
+class SitesDirectoryHardeningTest extends WebTestBase {
+  use StringTranslationTrait;
+
+  /**
+   * Tests the default behavior to restrict directory permissions is enforced.
+   *
+   * Checks both the the current sites directory and settings.php.
+   */
+  public function testSitesDirectoryHardening() {
+    $site_path = $this->kernel->getSitePath();
+    $settings_file = $this->settingsFile($site_path);
+
+    // First, we check based on what the initial install has set.
+    $this->assertTrue(drupal_verify_install_file($site_path, FILE_NOT_WRITABLE, 'dir'), new FormattableMarkup('Verified permissions for @file.', array('@file' => $site_path)));
+
+    // We intentionally don't check for settings.local.php as that file is
+    // not created by Drupal.
+    $this->assertTrue(drupal_verify_install_file($settings_file, FILE_EXIST|FILE_READABLE|FILE_NOT_WRITABLE), new FormattableMarkup('Verified permissions for @file.', array('@file' => $settings_file)));
+
+    $this->makeWritable($site_path);
+    $this->checkSystemRequirements();
+
+    $this->assertTrue(drupal_verify_install_file($site_path, FILE_NOT_WRITABLE, 'dir'), new FormattableMarkup('Verified permissions for @file after manual permissions change.', array('@file' => $site_path)));
+    $this->assertTrue(drupal_verify_install_file($settings_file, FILE_EXIST|FILE_READABLE|FILE_NOT_WRITABLE), new FormattableMarkup('Verified permissions for @file after manual permissions change.', array('@file' => $settings_file)));
+  }
+
+  /**
+   * Tests writable files remain writable when directory hardening is disabled.
+   */
+  public function testSitesDirectoryHardeningConfig() {
+    $site_path = $this->kernel->getSitePath();
+    $settings_file = $this->settingsFile($site_path);
+
+    // Disable permissions enforcement.
+    $settings = Settings::getAll();
+    $settings['skip_permissions_hardening'] = TRUE;
+    new Settings($settings);
+    $this->assertTrue(Settings::get('skip_permissions_hardening'), 'Able to set hardening to true');
+    $this->makeWritable($site_path);
+
+    // Manually trigger the requirements check.
+    $requirements = $this->checkSystemRequirements();
+    $this->assertEqual(REQUIREMENT_WARNING, $requirements['configuration_files']['severity'], 'Warning severity is properly set.');
+    $this->assertEqual($this->t('Protection disabled'), (string) $requirements['configuration_files']['description']['#context']['configuration_error_list']['#items'][0], 'Description is properly set.');
+
+    $this->assertTrue(is_writable($site_path), 'Site directory remains writable when automatically fixing permissions is disabled.');
+    $this->assertTrue(is_writable($settings_file), 'settings.php remains writable when automatically fixing permissions is disabled.');
+
+    // Re-enable permissions enforcement.
+    $settings = Settings::getAll();
+    $settings['skip_permissions_hardening'] = FALSE;
+    new Settings($settings);
+
+    // Manually trigger the requirements check.
+    $this->checkSystemRequirements();
+
+    $this->assertFalse(is_writable($site_path), 'Site directory is protected when automatically fixing permissions is enabled.');
+    $this->assertFalse(is_writable($settings_file), 'settings.php is protected when automatically fixing permissions is enabled.');
+  }
+
+  /**
+   * Checks system runtime requirements.
+   *
+   * @return array
+   *   An array of system requirements.
+   */
+  protected function checkSystemRequirements() {
+    module_load_install('system');
+    return system_requirements('runtime');
+  }
+
+  /**
+   * Makes the given path and settings file writable.
+   *
+   * @param string $site_path
+   *   The sites directory path, such as 'sites/default'.
+   */
+  protected function makeWritable($site_path) {
+    chmod($site_path, 0755);
+    chmod($this->settingsFile($site_path), 0644);
+  }
+
+  /**
+   * Returns the path to settings.php
+   *
+   * @param string $site_path
+   *   The sites subdirectory path.
+   *
+   * @return string
+   *   The path to settings.php.
+   */
+  protected function settingsFile($site_path) {
+    $settings_file = $site_path . '/settings.php';
+    return $settings_file;
+  }
+}

core/modules/system/system.install

@@ -365,12 +365,25 @@ function system_requirements($phase) {
     else {
       $site_path = DrupalKernel::findSitePath(Request::createFromGlobals());
     }
-    if (!drupal_verify_install_file($site_path, FILE_NOT_WRITABLE, 'dir')) {
-      $conf_errors[] = t("The directory %file is not protected from modifications and poses a security risk. You must change the directory's permissions to be non-writable.", array('%file' => $site_path));
+    // Allow system administrators to disable permissions hardening for the site
+    // directory. This allows additional files in the site directory to be
+    // updated when they are managed in a version control system.
+    if (Settings::get('skip_permissions_hardening')) {
+      $conf_errors[] = t('Protection disabled');
+      // If permissions hardening is disabled, then only show a warning for a
+      // writable file, as a reminder, rather than an error.
+      $file_protection_severity = REQUIREMENT_WARNING;
+    }
+    else {
+      // In normal operation, writable files or directories are an error.
+      $file_protection_severity = REQUIREMENT_ERROR;
+      if (!drupal_verify_install_file($site_path, FILE_NOT_WRITABLE, 'dir')) {
+        $conf_errors[] = t("The directory %file is not protected from modifications and poses a security risk. You must change the directory's permissions to be non-writable.", array('%file' => $site_path));
+      }
     }
     foreach (array('settings.php', 'settings.local.php', 'services.yml') as $conf_file) {
       $full_path = $site_path . '/' . $conf_file;
-      if (file_exists($full_path) && !drupal_verify_install_file($full_path, FILE_EXIST|FILE_READABLE|FILE_NOT_WRITABLE)) {
+      if (file_exists($full_path) && (Settings::get('skip_permissions_hardening') || !drupal_verify_install_file($full_path, FILE_EXIST|FILE_READABLE|FILE_NOT_WRITABLE))) {
         $conf_errors[] = t("The file %file is not protected from modifications and poses a security risk. You must change the file's permissions to be non-writable.", array('%file' => $full_path));
       }
     }
@@ -393,7 +406,7 @@ function system_requirements($phase) {
       }
       $requirements['configuration_files'] = array(
         'value' => t('Not protected'),
-        'severity' => REQUIREMENT_ERROR,
+        'severity' => $file_protection_severity,
         'description' => $description,
       );
     }

sites/example.settings.local.php

@@ -93,3 +93,15 @@ $settings['extension_discovery_scan_tests'] = TRUE;
  * using these parameters in a request to rebuild.php.
  */
 $settings['rebuild_access'] = TRUE;
+
+/**
+ * Skip file system permissions hardening.
+ *
+ * The system module will periodically check the permissions of your site's
+ * site directory to ensure that it is not writable by the website user. For
+ * sites that are managed with a version control system, this can cause problems
+ * when files in that directory such as settings.php are updated, because the
+ * user pulling in the changes won't have permissions to modify files in the
+ * directory.
+ */
+$settings['skip_permissions_hardening'] = TRUE;