oss-security - Re: DNS vulnerability: other relevant software

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Date: Thu, 10 Jul 2008 13:19:14 +0800
From: Eugene Teo <eteo@...hat.com>
To: oss-security@...ts.openwall.com
Subject: Re: DNS vulnerability: other relevant software

Mark J Cox wrote:
>> Additionally, Debian has noted (DSA 1605-1) that the GNU libc stub
>> resolver could benefit from random query source ports as well, but
>> no patches are currently available to implement this:
> 
> Note that GNU libc stub resolver when used with a recent kernel
> (2.6.24+) will give you random UDP source ports on each request because
> of this Linux commit:
> 
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=32c1da70810017a98aa6c431a5494a302b6b9a30
> 
> 
> Vendors may with to consider backporting that kernel patch as an
> effective mitigation without requiring glibc changes (and with the
> advantage of being able to be have a customized range using
> ip_local_port_range etc)

I have backported the kernel patch to apply cleanly to various versions
of Red Hat Enterprise Linux kernels. Vendors interested in the patch can
find it at:

https://bugzilla.redhat.com/show_bug.cgi?id=454566

Thanks, Eugene
-- 
Eugene Teo / Red Hat Security Response Team

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