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/AuthExt.php

@@ -0,0 +1,56 @@
+<?php
+namespace MRBS\Auth;
+
+/**
+ * Authentication scheme that uses an external script as the source for user authentication.
+ *
+ * To use this authentication scheme, set the following things in config.inc.php:
+ *
+ *     $auth["realm"] = "MRBS"; // Or any other string
+ *     $auth["type"] = "ext";
+ *     $auth["prog"] = "authenticationprogram"; // The full path to the external script
+ *     $auth["params"] = "<...>"; // Parameters to pass to the script; #USERNAME# and #PASSWORD#
+ *                                // will be expanded to the values typed by the user, e.g.
+ *                                // "/etc/htpasswd #USERNAME# #PASSWORD#"
+ *
+ * Then, you may configure admin users:
+ *
+ *     $auth["admin"][] = "username1";
+ *     $auth["admin"][] = "username2";
+ *
+ */
+class AuthExt extends Auth
+{
+  public function validateUser(
+    #[\SensitiveParameter]
+    ?string $user,
+    #[\SensitiveParameter]
+    ?string $pass)
+  {
+    global $auth;
+
+    // Check if we do not have a username/password
+    if(!isset($user) || !isset($pass))
+    {
+      return false;
+    }
+
+    // Generate the command line
+    $cmd = $auth["prog"] . ' ' . $auth["params"];
+    $cmd = str_replace('#USERNAME#', escapeshellarg($user), $cmd);
+    $cmd = str_replace('#PASSWORD#', escapeshellarg($pass), $cmd);
+
+    // Run the program
+    exec($cmd, $output, $ret);
+
+    // If it succeeded, return success
+    if ($ret == 0)
+    {
+      return $user;
+    }
+
+    // return failure
+    return false;
+  }
+
+}