session_start() 有关非法字符、空会话 ID 和失败会话的问题

Question

所以，我意识到这是一个重复的问题，但是，这显然是一个错误，但原帖已有 5 年历史，但也有人说这是一次恶意攻击...@987654321 @

处理此问题的最新正确方法是什么？

我的错误日志显示：

[30-Sep-2015 10:12:37 UTC] PHP 警告：session_start()：会话 id 太长或包含非法字符，有效字符为 az、AZ、0-9 和 '-,' in /home/ACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php 在第 27 行

[2015 年 9 月 30 日 10:12:37 UTC] PHP 警告：session_start()：无法在 /home/ACCOUNT/public_html/wp-content/plugins/cusplugin/cusplugin.php 中使用空会话 ID 启动会话第 21 行

[2015 年 9 月 30 日 10:12:37 UTC] PHP 警告：session_start()：无法在 /home/ACCOUNT/public_html/wp-content/plugins/cusplugin/cusplugin.php 中使用空会话 ID 启动会话第 377 行

[2015 年 9 月 30 日 10:12:37 UTC] PHP 警告：session_start()：无法在 /home/ACCOUNT/public_html/wp-content/plugins/cusplugin/cusplugin.php 中使用空会话 ID 启动会话第718行

[2015 年 9 月 30 日 10:12:50 UTC] PHP 警告：未知：会话 id 太长或包含非法字符，有效字符为 az、AZ、0-9 和 Unknown on第 0 行

[2015 年 9 月 30 日 10:12:50 UTC] PHP 警告：未知：无法写入会话数据（文件）。请在第 0 行的 Unknown 中验证 session.save_path 的当前设置是否正确（/tmp）

我的完整日志：

[30-Sep-2015 10:12:37 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[30-Sep-2015 10:12:37 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[30-Sep-2015 10:12:37 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[30-Sep-2015 11:12:37 Europe/London] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 718
[30-Sep-2015 11:12:37 Europe/London] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[30-Sep-2015 10:12:49 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[30-Sep-2015 10:12:50 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[30-Sep-2015 10:12:50 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[30-Sep-2015 10:12:50 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[30-Sep-2015 10:12:50 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[30-Sep-2015 10:12:50 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[30-Sep-2015 10:12:50 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[30-Sep-2015 10:12:50 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[30-Sep-2015 10:12:51 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 718
[30-Sep-2015 10:12:51 UTC] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[30-Sep-2015 10:12:53 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[30-Sep-2015 10:12:53 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[30-Sep-2015 10:12:53 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[30-Sep-2015 10:12:53 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[30-Sep-2015 10:12:53 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[30-Sep-2015 10:13:04 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[30-Sep-2015 10:13:04 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[30-Sep-2015 10:13:04 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[30-Sep-2015 10:13:04 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 718
[30-Sep-2015 10:13:04 UTC] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[01-Oct-2015 04:47:21 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[01-Oct-2015 04:47:21 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[01-Oct-2015 04:47:21 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[01-Oct-2015 04:47:21 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[01-Oct-2015 04:47:21 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[01-Oct-2015 05:47:22 Europe/London] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[01-Oct-2015 05:47:22 Europe/London] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[01-Oct-2015 04:47:22 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[01-Oct-2015 04:47:22 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 718
[01-Oct-2015 04:47:22 UTC] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[01-Oct-2015 04:47:24 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[01-Oct-2015 04:47:24 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 377
[01-Oct-2015 04:47:24 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[01-Oct-2015 04:47:24 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[01-Oct-2015 04:47:24 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[01-Oct-2015 23:10:23 UTC] PHP Warning:  in_array() expects parameter 2 to be array, null given in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 492
[01-Oct-2015 23:11:15 UTC] PHP Warning:  in_array() expects parameter 2 to be array, null given in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 492[02-Oct-2015 08:59:42 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[02-Oct-2015 08:59:42 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[02-Oct-2015 08:59:42 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[02-Oct-2015 09:59:42 Europe/London] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 739
[02-Oct-2015 09:59:42 Europe/London] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[02-Oct-2015 08:59:44 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[02-Oct-2015 08:59:45 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[02-Oct-2015 08:59:45 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[02-Oct-2015 08:59:45 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[02-Oct-2015 08:59:45 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[02-Oct-2015 08:59:46 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[02-Oct-2015 08:59:46 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[02-Oct-2015 08:59:46 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[02-Oct-2015 08:59:46 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 739
[02-Oct-2015 08:59:46 UTC] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[02-Oct-2015 08:59:52 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[02-Oct-2015 08:59:52 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[02-Oct-2015 08:59:52 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[02-Oct-2015 08:59:52 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[02-Oct-2015 08:59:52 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[03-Oct-2015 04:51:46 UTC] PHP Warning:  require(ABSPATHwp-includes/load.php): failed to open stream: No such file or directory in /home/HOSTINGACCOUNT/public_html/wp-settings.php on line 21
[03-Oct-2015 04:51:46 UTC] PHP Warning:  require(ABSPATHwp-includes/load.php): failed to open stream: No such file or directory in /home/HOSTINGACCOUNT/public_html/wp-settings.php on line 21
[03-Oct-2015 04:51:46 UTC] PHP Fatal error:  require(): Failed opening required 'ABSPATHwp-includes/load.php' (include_path='.:/usr/lib/php:/usr/local/lib/php') in /home/HOSTINGACCOUNT/public_html/wp-settings.php on line 21
[03-Oct-2015 08:09:48 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[03-Oct-2015 08:09:48 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[03-Oct-2015 08:09:48 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[03-Oct-2015 09:09:49 Europe/London] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 727
[03-Oct-2015 09:09:49 Europe/London] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[03-Oct-2015 08:09:52 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[03-Oct-2015 08:09:52 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[03-Oct-2015 08:09:52 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[03-Oct-2015 08:09:52 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[03-Oct-2015 08:09:52 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0
[03-Oct-2015 08:09:55 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[03-Oct-2015 08:09:55 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[03-Oct-2015 08:09:55 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[03-Oct-2015 08:09:55 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 727
[03-Oct-2015 08:09:55 UTC] PHP Fatal error:  Call to a member function check_connection() on a non-object in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/simple-press/sp-api/sp-api-wpdb.php on line 439
[03-Oct-2015 08:09:57 UTC] PHP Warning:  session_start(): The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/wl-coupon/wishlist-coupon20.php on line 27
[03-Oct-2015 08:09:57 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 385
[03-Oct-2015 08:09:57 UTC] PHP Warning:  session_start(): Cannot start session with empty session ID in /home/HOSTINGACCOUNT/public_html/wp-content/plugins/customplugin/customplugin.php on line 21
[03-Oct-2015 08:09:57 UTC] PHP Warning:  Unknown: The session id is too long or contains illegal characters, valid characters are a-z, A-Z, 0-9 and '-,' in Unknown on line 0
[03-Oct-2015 08:09:57 UTC] PHP Warning:  Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/tmp) in Unknown on line 0

正如您所看到的，它们似乎都是成群发生的，看看 9 月 30 日，它在 1 分钟内发生了很多次，然后在一天的其余时间都不会发生......

它为 customplugin、简单的新闻论坛（我认为）和 Wishlist Coupon 2.0 抛出 sessionid 问题

我的自定义插件代码有：

if(!session_id()) {
    session_start();
}

我尝试了下面的选项 2，但它没有帮助/解决问题。

导致某些错误的其他 WordPress 插件的 sn-p：

class WishListCoupon20 extends WishListPlugin {
    public function __construct($file, $slug, $sku, $name, $link_name, $prefix, $require_wlm) {
        parent::__construct($file, $slug, $sku, $name, $link_name, $prefix, $require_wlm);

        session_start();

另一个堆栈溢出帖子有一些解决该问题的变体，但我不确定什么是正确的，因为该帖子已有 5 年以上的历史了，您可能希望在那段时间修复一个错误。

感谢 Sergey Eremin 的选项 1：

<?php
    function my_session_start()
    {
        if (ini_get('session.use_cookies') && isset($_COOKIE['PHPSESSID'])) {
            $sessid = $_COOKIE['PHPSESSID'];
        } elseif (!ini_get('session.use_only_cookies') && isset($_GET['PHPSESSID'])) {
            $sessid = $_GET['PHPSESSID'];
        } else {
            session_start();
            return false;
        }

        if (!preg_match('/^[a-z0-9]{32}$/', $sessid)) {
            return false;
        }
        session_start();

        return true;
    }
?>

感谢 danjfoley 的选项 2：

try {
   session_start();
} catch(ErrorExpression $e) {
   session_regenerate_id();
   session_start();
}

感谢 Cendak 的选项 3（使用 Andron 以前的解决方案）

function my_session_start()
{
      $sn = session_name();
      if (isset($_COOKIE[$sn])) {
          $sessid = $_COOKIE[$sn];
      } else if (isset($_GET[$sn])) {
          $sessid = $_GET[$sn];
      } else {
          return session_start();
      }

     if (!preg_match('/^[a-zA-Z0-9,\-]{22,40}$/', $sessid)) {
          return false;
      }
      return session_start();
}

if ( !my_session_start() ) {
    session_id( uniqid() );
    session_start();
    session_regenerate_id();
}

感谢 Andron 的选项 4：

<?php
    function my_session_start()
    {
        $sn = session_name();
        if (isset($_COOKIE[$sn])) {
            $sessid = $_COOKIE[$sn];
        } else if (isset($_GET[$sn])) {
            $sessid = $_GET[$sn];
        } else {
            session_start();
            return false;
        }

       if (!preg_match('/^[a-zA-Z0-9,\-]{22,40}$/', $sessid)) {
            return false;
        }
        session_start();

       return true;
    }
?>

感谢 alpere 的选项 5：

$ok = @session_start();
if(!$ok){
session_regenerate_id(true); // replace the Session ID
session_start(); 
}

或者……有没有更好的办法。

Answer 1

问题：

session_start() 依赖于$_COOKIE[session_name()]，因此，如果您将 cookie 值编辑为 #$#$FDSFSR#"#"$"#$" 之类的值，或者只是清空它（而不是删除 cookie）并使用您的代码刷新页面：

if (!session_id()) {
    session_start();
}

生成以下警告：

PHP 警告：session_start()：会话 id 太长或包含 非法字符，有效字符为 a-z、A-Z、0-9 和 '-,' in /home/username/public_html/session_start.php 在第 7 行

发生这种情况是因为php是检查session_id()存在，实际上它存在，但包含不允许的非法字符作为session_id name。

a 有效 session id可能包含只有数字，字母a到z（upper和小写），逗号和dash（[-,a-zA-Z0-9]）之间的1 和 128 个字符。

---

我的解决方案：

检查是否$_COOKIE[session_name()] 987654334 session_start()，否则，删除会话cookie和session_start()，类似：

function safeSession() {
    if (isset($_COOKIE[session_name()]) AND preg_match('/^[-,a-zA-Z0-9]{1,128}$/', $_COOKIE[session_name()])) {
        session_start();
    } elseif (isset($_COOKIE[session_name()])) {
        unset($_COOKIE[session_name()]);
        session_start(); 
    } else {
        session_start(); 
    }
}

开始会话：

safeSession();

---

注意事项：

1 - 987654338 @在您的php.ini AS session.name = SOMETHING（默认为PHPSESSID），所以，您可能正在寻找一个饼干匹配session.name。您可以使用session_name() 函数来检索它。

2 - Hackers可以使用SEQUE Cookie操作，从您的服务器转储信息（username和path）如果ini_set('display_errors', 1); @ / p>

3 - session_regenerate_id(true) 有效，但是因为它会在分配新的session_id 之前检查当前的session_id，所以会生成警告。

4 - 我已经测试了几个无效的会话名称的代码，没有生成错误或警告，一切都在工作和打算。

---

参考资料：

session.c Source Code

Answer 2

我敢打赌，你此时正受到攻击。这意味着例如有人操纵了您的会话 cookie。

由于session_start();是一个系统函数，我认为它不会产生无效的id。

在我看来，选项 2 是最好的。但如果我没记错的话，你需要为此设置一个自定义错误处理程序。

This answer 对我来说似乎更好：

$ok = @session_start();
if(!$ok){
   //Hello Hacker ;)
   session_regenerate_id(true); // replace the Session ID
   session_start(); 
}

Answer 3

我喜欢Pedro Lobito的解释，但算法可以改进：

if (isset($_COOKIE[session_name()]) && 0 === preg_match('/^[-,a-zA-Z0-9]{1,128}$/', $_COOKIE[session_name()])) {
    unset($_COOKIE[session_name()]);
}

if ('' === session_id()) {
    session_start();
}