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Date:      Tue, 1 Dec 2009 18:50:07 +0100
From:      Oliver Pinter <oliver.pntr@gmail.com>
To:        "Sean C. Farley" <scf@freebsd.org>
Cc:        Dan Lukes <dan@obluda.cz>, freebsd security <freebsd-security@freebsd.org>
Subject:   Re: Upcoming FreeBSD Security Advisory
Message-ID:  <6101e8c40912010950j70540b6bj140eddbf0f3d7bba@mail.gmail.com>
In-Reply-To: <alpine.BSF.2.00.0912011047440.68765@thor.farley.org>
References:  <200912010120.nB11Kjm9087476@freefall.freebsd.org> <ov3Jq1IJ/c8KAXGQ501G8Os9xr8@Ll2tHa60cb%2BhiG8R4R8/VS21128> <20091201111627.GC4920@borusse.borussiapark> <86skbuet3x.fsf@ds4.des.no> <4B154635.2050209@obluda.cz> <alpine.BSF.2.00.0912011047440.68765@thor.farley.org>

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http://twitter.com/spendergrsec/status/6223864530
http://xorl.wordpress.com/2009/12/01/freebsd-ld_preload-security-bypass/


On 12/1/09, Sean C. Farley <scf@freebsd.org> wrote:
> On Tue, 1 Dec 2009, Dan Lukes wrote:
>
>> Dag-Erling Sm=F8rgrav napsal/wrote, On 12/01/09 14:12:
>>> As to the second: yes, 6.1 is most likely affected.
>>
>> Probably no.
>>
>> The older algorithm used in 6.1 looks like
>> -----------------
>> if (trusted) {
>> 	variable =3D getenv(NAME);
>>        ....
>> -----------------
>>
>> The affected algorithm looks like:
>> -----------------
>> if (!trusted) {
>> 	unsetenv(NAME);
>> 	...
>> };
>> variable =3D getenv(NAME);
>> -----------------
>>
>> As far as I know such change has been MFCed into 6.3, 6.4, 7.x but not
>> into 6.1. So 6.1 should not be affected by this bug (but remain
>> vulnerable to problem that triggered the change of old algorithm to
>> new).
>
> That is correct.  6.x should not be affected.  The security issue exists
> with the combination of the getenv() to unsetenv() change in rtld.c and
> the addition of the new env code.  The unsetenv() in 6.x would not stop
> if environ was corrupted.
>
> Sean
> --
> scf@FreeBSD.org



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