From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Kees Cook <kees.cook@canonical.com>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [Security] [PATCH v3 0/4] x86: clear XD_DISABLED flag on Intel to regain NX
Date: Wed, 10 Nov 2010 00:21:53 +0000 [thread overview]
Message-ID: <20101110002153.7af92a1f@lxorguk.ukuu.org.uk> (raw)
In-Reply-To: <20101109235314.GD5876@outflux.net>
> Only Intel has this problem (it's the only CPU that defines this MSR), so
> that'll reduce it. But Google is of no help to me on this; where can I find
> these documents?
www.intel.com 8)
> > I'm not specifically aware of any but I do know for example that there
> > are other CPU BIOS disablable features that some systems disable in the
> > BIOS for good reason (an ancient example being the original Pentium
> > REP MOVS optimisation on some steppings)
>
> By definition there should be fewer errata CPUs than those than need their
> BIOS ignored, so I still think this patch makes sense (especially since it
> can trivially be worked around with the noexec=off boot option).
We need to be sure because the last thing you want is even 1% of your 10%
of users to sudden get magical random memory corruption from overriding
something wrongly !
It's definitely worth checking and worth doing because even if there is
one (and I have no idea if there is) it'll tell you which steppings
Alan
next prev parent reply other threads:[~2010-11-10 0:23 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-09 18:11 Kees Cook
2010-11-09 18:14 ` [PATCH 1/4] x86: rename verify_cpu_64.S to verify_cpu.S Kees Cook
2010-11-09 18:46 ` Pekka Enberg
2010-11-09 19:00 ` Kees Cook
2010-11-09 19:59 ` Pekka Enberg
2010-11-09 19:02 ` Kees Cook
2010-11-09 19:11 ` Pekka Enberg
2010-11-09 18:15 ` [PATCH 2/4] x86: clear XD_DISABLED flag on Intel to regain NX Kees Cook
2010-11-10 16:11 ` Andi Kleen
2010-11-10 16:47 ` Kees Cook
2010-11-10 17:42 ` Andi Kleen
2010-11-10 18:15 ` Kees Cook
2010-11-09 18:15 ` [PATCH 3/4] x86: call verify_cpu during 32bit CPU startup Kees Cook
2010-11-09 19:09 ` Pekka Enberg
2010-11-09 19:19 ` Kees Cook
2010-11-09 19:46 ` Pekka Enberg
2010-11-09 19:56 ` Kees Cook
2010-11-09 20:28 ` Pekka Enberg
2010-11-09 20:48 ` Kees Cook
2010-11-09 20:50 ` Pekka Enberg
2010-11-09 18:15 ` [PATCH 4/4] x86: only CPU features determine NX capabilities Kees Cook
2010-11-09 18:31 ` [Security] [PATCH v3 0/4] x86: clear XD_DISABLED flag on Intel to regain NX Alan Cox
2010-11-09 18:56 ` Kees Cook
2010-11-09 22:50 ` Alan Cox
2010-11-09 23:53 ` Kees Cook
2010-11-10 0:21 ` Alan Cox [this message]
2010-11-10 0:43 ` Kees Cook
2010-11-10 1:10 ` Kees Cook
2010-11-10 11:11 ` Alan Cox
2010-11-10 11:15 ` Ingo Molnar
2010-11-11 15:15 ` Rogier Wolff
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