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Re: CVE request: ruby file creation due in insertion of illegal NUL character


From: Matthias Weckbecker <mweckbecker () suse de>
Date: Wed, 17 Oct 2012 12:25:28 +0200

On Wednesday 17 October 2012 11:44:35 Fabian Keil wrote:
Daniel Kahn Gillmor <dkg () fifthhorseman net> wrote:
On 10/16/2012 08:40 AM, Matthias Weckbecker wrote:
Technically, this would also apply to Perl (at least with 5.12.3).

It's also the case with perl 5.14.2 (just tested). :/

At least for Perl I consider this a feature.


I agree. I also think that an application which lets such things happen (ie
allow arbitrary content to be passed to open()) is rather to blame than the
language (/interpreter) itself. But the same applies to Ruby, IMO.

The NUL byte is a special character and allows trailing white
space in the filename that is otherwise stripped. This is
(more or less) documented in perlopentut(1).

It also seems unlikely that someone adds NUL bytes to the
white list of acceptable characters by accident, and if there
is no white list in the first place, the Perl script probably
has bigger issues.


Ack.

Fabian

Matthias

-- 
Matthias Weckbecker, Senior Security Engineer, SUSE Security Team
SUSE LINUX Products GmbH, Maxfeldstr. 5, D-90409 Nuernberg, Germany
Tel: +49-911-74053-0;  http://suse.com/
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