MRBS 1.12.2 等保2.0二级整改完整提交

包含：登录失败锁定、90天密码有效期、30分钟会话超时、
强制改密、登录审计日志、屏幕水印、企业背景图、
备案信息固定底部、favicon、JS空集合保护、
会话过期体验优化（403 JSON）、display_errors 关闭、
固定 key 根治 Integrity check failed 等全部改动

注意：config.inc.php/.htaccess/.user.ini 含敏感信息，
通过 .gitignore 排除，勿推送到公开仓库。

lib/MRBS/Auth/AuthDbAbstract.php

@@ -0,0 +1,59 @@
+<?php
+declare(strict_types=1);
+namespace MRBS\Auth;
+
+use MRBS\DB\DB;
+
+abstract class AuthDbAbstract extends Auth
+{
+  protected $db_table;
+  protected $column_name_username;
+  protected $column_name_display_name;
+
+  /**
+   * Returns a database connection.
+   *
+   * The connection isn't established in the constructor, but here only when it's really necessary, as it can be
+   * expensive establishing a connection when the server is remote.  For example, `method_exists(auth(), 'method')`
+   * will end up calling the constructor, but a connection isn't needed just for method_exists().
+   */
+  abstract protected function connection() : ?DB;
+
+
+  /**
+   * Return an array of users, indexed by 'username' and 'display_name'.
+   */
+  public function getUsernames() : array
+  {
+    if (isset($this->column_name_display_name) && ($this->column_name_display_name !== ''))
+    {
+      $display_name_column = $this->column_name_display_name;
+    }
+    else
+    {
+      $display_name_column = $this->column_name_username;
+    }
+
+    $quoted_column_name_display_name = $this->connection()->quote($display_name_column);
+    $quoted_column_name_username = $this->connection()->quote($this->column_name_username);
+
+    $sql = "SELECT $quoted_column_name_username AS username,
+                   CASE
+                       WHEN $quoted_column_name_display_name IS NOT NULL AND $quoted_column_name_display_name!='' THEN $quoted_column_name_display_name
+                       ELSE $quoted_column_name_username
+                   END AS display_name
+              FROM " . $this->connection()->quote($this->db_table) . "
+             WHERE $quoted_column_name_username IS NOT NULL
+          ORDER BY display_name";
+
+    $res = $this->connection()->query($sql);
+
+    $users =  $res->all_rows_keyed();
+    // Although the users may already be sorted, we sort them again because MRBS
+    // offers an option for sorting by first or last name.
+    self::sortUsers($users);
+
+    return $users;
+  }
+
+}