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Date: Wed, 11 Jul 2012 11:29:22 -0600
From: Kurt Seifried <kseifried@...hat.com>
To: oss-security@...ts.openwall.com
CC: Marcus Meissner <meissner@...e.de>
Subject: Re: CVE Request: Overflow fix in bash 4.2 patch 33

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On 07/11/2012 10:15 AM, Marcus Meissner wrote:
> Hi,
> 
> the bash maintainer kindly mailed us and other vendors a
> notification of a overflow in the bash "test" builtin when
> "/dev/fd/..." filenames are used.
> 
> ftp://ftp.gnu.org/pub/gnu/bash/bash-4.2-patches/bash42-033
> 
> Reproducer: test -e /dev/fd/111111111111111111111111111111111
> 
> Problem is caught by -D_FORTIFY_SOURCE=2 if enabled, and likely
> also by -fstack-protector (not tested)
> 
> Goes all the way back to old bashes.
> 
> The likeliness of people able to inject those filenames into shell
> scripts and not being able to execute shellcode themselves is
> however slim. (setuid root shell scripts are not possible.)
> 
> Security (CVE) relevant scenario we thought of is breaking out of
> a restricted shell mode.
> 
> Ciao, Marcus

Can you give a more concrete example, e.g. you're talking about
http://www.gnu.org/software/bash/manual/html_node/The-Restricted-Shell.html
I assume? Are we simply talking about violating those restrictions?

- -- 
Kurt Seifried Red Hat Security Response Team (SRT)
PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993



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