Home page logo

fulldisclosure logo Full Disclosure mailing list archives

Re: {Java,PHP} Server Exploits
From: Valdis.Kletnieks () vt edu
Date: Wed, 09 Feb 2011 15:13:11 -0500

On Wed, 09 Feb 2011 20:54:41 +0100, Christian Sciberras said:

    echo 'Try 2 => '.$f.'</br>';

Plus, I'm a bit amazed such a bug exists in PHP - since converting to
floating point is a trivial operation, it should have been limited and
safe-guarded from the start.

Take a careful gander at that number, then go look at the floating point spec -
it's a specific corner case that isn't obviously trivial to get right (doing
floating point *right* is a lot harder than it looks - take a class on
numerical methods sometime, you spend 75% of your time dealing with rounding
errors in the last bit).

Having said that, anybody writing floating point support for a package should
probably google 'floating point paranoia' and learn what sort of things to test
for. :)

Attachment: _bin

Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]