深入讲解PHP的对象注入(Object Injection)

<?php
class test{
 public $varr1="abc";
 public $varr2="123";
 public function echoP(){
  echo $this->varr1."<br>";
 }
 public function __construct(){
  echo "__construct<br>";
 }
 public function __destruct(){
  echo "__destruct<br>";
 }
 public function __toString(){
  return "__toString<br>";
 }
 public function __sleep(){
  echo "__sleep<br>";
  return array('varr1','varr2');
 }
 public function __wakeup(){
  echo "__wakeup<br>";
 }
}

$obj = new test();  //实例化对象，调用__construct()方法，输出__construct
$obj->echoP();   //调用echoP()方法，输出"abc"
echo $obj;    //obj对象被当做字符串输出，调用__toString()方法，输出__toString
$s =serialize($obj);  //obj对象被序列化，调用__sleep()方法，输出__sleep
echo unserialize($s);  //$s首先会被反序列化，会调用__wake()方法，被反序列化出来的对象又被当做字符串，就会调用_toString()方法。
// 脚本结束又会调用__destruct()方法，输出__destruct
?>

<?php
class LogClass {
 public $logfilename = "";
 public function logdata($text) {
  echo "log data".$text."<br/>";
  file_put_contents($this->logfilename,$text,FILE_APPEBD);
 }

 public function __destruct() {
  echo 'deletes'.$this->logfilename;
  unlink(dirname(__FILE__).'/'.$this->logfilename);
 }
}
?>

<?php
include "index.php";
$obj = new LogClass();
$obj->logfilename = "login.log";
$obj->logdata('记录日志');
?>

<?php
include "logfile.php";
// some codes the use the LogClass
class User {
 public $age = 0;
 public $name = '';
 public function print_data() {
  echo "User".$this->name."is".$this->age."years old.<br/>";
 }
}

// 从用户接受输入发序列化为User对象
$usr = unserialize($_GET["user"]);
?>

news.php?user=O:4:"User":2:{s:3:"age";i:20;s:4:"name";s:4:"John”;}

news.php?user=O:8:"LogClass":1:{s:11:"logfilename";s:9:".htaccess";}

<?php
class FileClass {
 public $filename = "error.log";
 public function __toString() {
 echo "filename发生了变化==>" . $this->filename ;
  return @file_get_contents($this->filename);
 }
}

class UserClass {
 public $age = 0;
 public $name = '';
 public function __toString() {
  return 'User '.$this->name." is ".$this->age.' years old. <br/>';
 }
}

$obj = unserialize($_GET['usr']);
echo $obj;  //调用obj的__toString()方法
?>