From: Marcelo Tosatti <mtosatti@redhat.com>
To: Solar Designer <solar@openwall.com>
Cc: Willy Tarreau <wtarreau@hera.kernel.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] introduce CONFIG_BINFMT_ELF_AOUT
Date: Sun, 20 Aug 2006 21:16:29 -0300 [thread overview]
Message-ID: <20060821001628.GC2861@dmt> (raw)
In-Reply-To: <20060819232556.GA16617@openwall.com>
On Sun, Aug 20, 2006 at 03:25:56AM +0400, Solar Designer wrote:
> Willy,
>
> I propose the attached patch (extracted from 2.4.33-ow1) for inclusion
> into 2.4.34-pre. (2.6 kernels could benefit from the same change, too.)
>
> The patch adds a new compile-time option to control the support for
> "ELF binaries with a.out format interpreters or a.out libraries".
> Without this patch, such support is enabled on every system that enables
> the support for ELF binaries - although 99% (100%?) of systems don't
> need this hybrid functionality. Moreover, this functionality poses a
> security risk - as proven in practice:
>
> http://www.isec.pl/vulnerabilities/isec-0021-uselib.txt
>
> This uselib() vulnerability did not affect default kernel builds with
> the -ow patch specifically due to separation of the unneeded/risky code
> into CONFIG_BINFMT_ELF_AOUT and having this option disabled by default.
> (Yes, this change in -ow patches pre-dates the discovery of the uselib()
> vulnerability.)
>
> The patch also changes CONFIG_BINFMT_AOUT to be disabled by default on
> archs that had it default to enabled. The a.out support is similarly
> risky and not audited/hardened with the same scrutiny that the ELF
> support has received.
I dislike this change. "Make a.out configurable" is a:
- "Hide the problems" trick, making it less likely for any potential bug to
be really fixed.
- Change not suitable for v2.4 inclusion: its not fixing _any_ serious problem.
We had this discussion before, didnt we?
next prev parent reply other threads:[~2006-08-21 0:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-19 23:25 [PATCH] introduce CONFIG_BINFMT_ELF_AOUT Solar Designer
2006-08-20 0:16 ` Willy Tarreau
2006-08-21 1:07 ` Solar Designer
2006-08-21 4:40 ` Willy Tarreau
2006-08-21 0:16 ` Marcelo Tosatti [this message]
2006-08-21 0:33 ` Solar Designer
2006-08-21 0:51 ` Marcelo Tosatti
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