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PHP import_request_variables() vs extract()
From: ascii <ascii () katamail com>
Date: Fri, 09 Mar 2007 01:11:28 +0100
Please note that also extract() will override any variable exluded
$GLOBALS but the main difference is that on http://it2.php.net/extract
you are advised to do not use "extract() against untrusted data, like
user-input ($_GET, ...)."
if you want to run old code that relies on register_globals temporarily,
make sure you use one of the non-overwriting extract_type values such
as EXTR_SKIP and be aware that you should extract in the same order
that's defined in variables_order within the php.ini
Infact extract() has a EXTR_SKIP flag that implement this bhreaviuw:
If there is a collision, don't overwrite the existing variable.
Using extract() with EXTR_SKIP will give you something like GLOBALS ON
that is safe if compared with what happens using extract($_GET); or
--- >8 --- >8 --- >8 --- >8 --- test1.php --- >8 --- >8 --- >8 --- >8
--- >8 --- >8 --- >8 --- >8 --- --------- --- >8 --- >8 --- >8 --- >8
Expected result: the _SERVER array will became a string
The morale is that while an insecure usage of extract() by a developer
could be his fault there is no secure usage of
import_request_variables() and this is surely a PHP fault.
Francesco 'ascii' Ongaro
Full-Disclosure - We believe in it.
Hosted and sponsored by Secunia - http://secunia.com/
- PHP import_request_variables() vs extract() ascii (Mar 08)