class PermissionAccessCheck

user.services.yml in drupal/core/modules/user/user.services.yml

drupal/core/modules/user/user.services.yml

access_check.permission in drupal/core/modules/user/user.services.yml

Drupal\user\Access\PermissionAccessCheck

class PermissionAccessCheck implements AccessCheckInterface {

  /**
   * Implements AccessCheckInterface::applies().
   */
  public function applies(Route $route) {
    return array_key_exists('_permission', $route
      ->getRequirements());
  }

  /**
   * Implements AccessCheckInterface::access().
   */
  public function access(Route $route, Request $request) {
    $permission = $route
      ->getRequirement('_permission');

    // @todo Replace user_access() with a correctly injected and session-using
    //   alternative.
    // If user_access() fails, return NULL to give other checks a chance.
    return user_access($permission) ? static::ALLOW : static::DENY;
  }

}