@(#)Mordred Labs advisory - Integer overflow in PHP array_pad() function

[Sir Mordred <mordred () s-mail com>]

//@(#) Mordred Security Labs advisory 

Release date: April 1, 2003 
Name: Integer overflow in PHP array_pad() function
Versions affected: all versions 
Risk: average
Author: Sir Mordred (mordred () s-mail com) 

I. Description: 

PHP is a widely-used general-purpose scripting language that is
especially suited for Web development and can be embedded into HTML.
Please visit http://www.php.net for more information about PHP.

II. Details: 

The function array_pad(array input, int pad_size, mixed pad_value) returns
a copy
of the input padded to size specified by pad_size with pad_value.

Unfortunately the implementation of this function suffers from an integer
overflow caused by 
a very long second argument and could allow a local/remote attacker in the
worst case 
to gain control over the web server.

The following short script will cause a httpd child to die:

$ cat t.php
<?php 
    array_pad(array(1,2,3), 0x40000003, "pad");
?>

III. Platforms tested

Linux 2.4 with Apache 1.3.27 / PHP 4.3.1

IV. Vendor response

Vendor has been contacted.


________________________________________________________________________
This letter has been delivered unencrypted. We'd like to remind you that
the full protection of e-mail correspondence is provided by S-mail
encryption mechanisms if only both, Sender and Recipient use S-mail.
Register at S-mail.com: http://www.s-mail.com