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Re: vulnerabilities in libbfd (CVE-2014-beats-me)
- From: Petr Machata <pmachata at redhat dot com>
- To: Pedro Alves <palves at redhat dot com>
- Cc: Yury Gribov <y dot gribov at samsung dot com>, Nicholas Clifton <nickc at redhat dot com>, "Maciej W. Rozycki" <macro at linux-mips dot org>, Michal Zalewski <lcamtuf at coredump dot cx>, bugtraq <bugtraq at securityfocus dot com>, binutils at sourceware dot org
- Cc: Mark Wielaard <mjw at redhat dot com>
- Date: Thu, 30 Oct 2014 16:23:37 +0100
- Subject: Re: vulnerabilities in libbfd (CVE-2014-beats-me)
- Authentication-results: sourceware.org; auth=none
- References: <CALx_OUBq4iRGZNPLdCuqXmehVV=6vhXN3J16ytzM91cFqVSAoQ at mail dot gmail dot com> <alpine dot LFD dot 2 dot 11 dot 1410271451411 dot 3413 at eddie dot linux-mips dot org> <54521A7F dot 4050501 at redhat dot com> <5452389B dot 502 at samsung dot com> <54524C50 dot 8010606 at redhat dot com>
Pedro Alves <email@example.com> writes:
> On 10/30/2014 01:09 PM, Yury Gribov wrote:
>> On 10/30/2014 02:01 PM, Nicholas Clifton wrote:
>>> Hi Maciej, Hi Michal,
>>> It is true however that there are still vulnerabilities in libbfd, and I
>>> for one would happy to see new bug reports exposing them. I can assure
>>> you that any such bug report reaching me will be treated seriously, and
>>> will be investigated and fixed as soon as possible.
>> We could cook a (simple) ELF fuzzer and run it on Binutils with
>> AddressSanitizer enabled. Perhaps there is one I'm unaware of?
> I've heard of Melkor - an ELF file format fuzzer. See:
> I believe Petr Machata (in CC now) ran this against elfutils, and
> it indeed exposed some bugs.
Yep, quite a few. Melkor is nice in that it doesn't fuzz fully
randomly, but when it tweaks a value, it also tweaks other dependent
values, so simple sanity checking doesn't tend to catch those.
If BFD validates offsets and sizes vs. actual underlying file or stream
sizes, it would be more robust in face of these corruptions. But
elfutils has largely been built with a policy of "if you don't trust it,
don't open it", and so all these problems consistently burn us.
I CC'd Mark Wielaard, the current elfutils maintainer. I saw Melkor
mentioned in his TODO, chances are he has more insights.