[2009-07-23 08:36 UTC] virus at tgu dot ru

Description:
------------
Environment variables specified for proc_open passed without check so safe_mode_allowed_env_vars and safe_mode_protected_env_vars settings are ignored.
So it become possible to use buffer overflow exploit with "LD_PRELOAD=evil_library.so" to bypass safe_mode restrictions and get access to any files acessible for apache uid.

In php.ini:
safe_mode = On
safe_mode_gid = On
safe_mode_include_dir =
safe_mode_exec_dir = /usr/bin/safe
safe_mode_allowed_env_vars = PHP_
safe_mode_protected_env_vars = LD_LIBRARY_PATH


Reproduce code:
---------------
<?
putenv("BLAHBLAH=123");
putenv("LD_LIBRARY_PATH=/no/way");
putenv("PHP_TESTVAR=allowed");
$env = array('BLAHBLAH' => '123', 'LD_LIBRARY_PATH' => '/no/way', 'PHP_TESTVAR' => 'allowed');
$dptspec = array(0 => array("pipe", "r"),
                 1 => array("pipe", "w"));
$fp = proc_open('env', $dptspec, $pipes, './', $env);
echo "<pre>";
while(!feof($pipes[1])) echo fgets($pipes[1], 1024);
fclose($pipes[1]);
echo "</pre>";
?>

Expected result:
----------------
Warning: putenv() [function.putenv]: Safe Mode warning: Cannot set environment variable 'BLAHBLAH' - it's not in the allowed list in /my/path/test.php on line 2

Warning: putenv() [function.putenv]: Safe Mode warning: Cannot override protected environment variable 'LD_LIBRARY_PATH' in /my/path/test.php on line 3

PHP_TESTVAR=allowed
PWD=/my/path

Actual result:
--------------
Warning: putenv() [function.putenv]: Safe Mode warning: Cannot set environment variable 'BLAHBLAH' - it's not in the allowed list in /my/path/test.php on line 2

Warning: putenv() [function.putenv]: Safe Mode warning: Cannot override protected environment variable 'LD_LIBRARY_PATH' in /my/path/test.php on line 3

LD_LIBRARY_PATH=/no/way
PHP_TESTVAR=allowed
BLAHBLAH=123
PWD=/my/path