From: Kees Cook <kees.cook@canonical.com>
To: Pekka Enberg <penberg@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] x86: call verify_cpu during 32bit CPU startup
Date: Tue, 9 Nov 2010 11:19:08 -0800 [thread overview]
Message-ID: <20101109191908.GO5876@outflux.net> (raw)
In-Reply-To: <AANLkTimzAaj1Z-jyCLBPKGzp_PWw2hwkYy_XeLo8CKPP@mail.gmail.com>
On Tue, Nov 09, 2010 at 09:09:18PM +0200, Pekka Enberg wrote:
> On Tue, Nov 9, 2010 at 8:15 PM, Kees Cook <kees.cook@canonical.com> wrote:
> > The XD_DISABLE-clearing side-effect needs to happen on 32bit CPU
> > start-up as well.
> >
> > Signed-off-by: Kees Cook <kees.cook@canonical.com>
>
> The patch description here is pretty damn terse. Why do we need the
> clearing for? Does not clearing XD_DISABLE cause some problem?
The clearing needs to happen for both 32bit and 64bit, but the 32bit init
routines were not calling verify_cpu() yet. This adds that path to gain the
side-effect. (See patch 0 for why clearing XD_DISABLE is important.)
--
Kees Cook
Ubuntu Security Team
next prev parent reply other threads:[~2010-11-09 19:19 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-09 18:11 [Security] [PATCH v3 0/4] x86: clear XD_DISABLED flag on Intel to regain NX 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 [this message]
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
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
-- strict thread matches above, loose matches on Subject: below --
2010-11-10 18:35 [Security] [PATCH v5 " Kees Cook
2010-11-10 18:35 ` [PATCH 3/4] x86: call verify_cpu during 32bit CPU startup Kees Cook
2010-11-14 6:33 ` Yinghai Lu
2010-11-09 22:17 [Security] [PATCH v4 0/4] x86: clear XD_DISABLED flag on Intel to regain NX Kees Cook
2010-11-09 22:18 ` [PATCH 3/4] x86: call verify_cpu during 32bit CPU startup Kees Cook
2010-06-19 5:50 [PATCH v2 0/4] x86: clear XD_DISABLED flag on Intel to regain NX Kees Cook
2010-06-19 5:52 ` [PATCH 3/4] x86: call verify_cpu during 32bit CPU startup Kees Cook
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