From: Kees Cook <kees.cook@canonical.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
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: Tue, 9 Nov 2010 10:56:04 -0800 [thread overview]
Message-ID: <20101109185604.GK5876@outflux.net> (raw)
In-Reply-To: <20101109183142.4ebfa737@lxorguk.ukuu.org.uk>
On Tue, Nov 09, 2010 at 06:31:42PM +0000, Alan Cox wrote:
> > In a review[1] of reported hardware being used by Ubuntu bug reporters,
> > almost 10% of systems had an incorrectly configured BIOS, leaving their
> > systems unable to use the NX features of their CPU.
>
> Ouch
Yeah :(
> > This change will clear the MSR_IA32_MISC_ENABLE_XD_DISABLE bit so that NX
> > cannot be inappropriately controlled by the BIOS on Intel CPUs. If, under
> > very strange hardware configurations, NX actually needs to be disabled,
> > "noexec=off" can be used to restore the prior behavior.
>
> Have you done an audit of CPU errata to ensure that none of these cases
> are ones where the BIOS has disabled it to avoid an erratum. I'd hate to
> turn it on and find out the BIOS actually turned it off for good reason !
Where can I find those details?
-Kees
--
Kees Cook
Ubuntu Security Team
next prev parent reply other threads:[~2010-11-09 18:56 UTC|newest]
Thread overview: 31+ 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
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 [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20101109185604.GK5876@outflux.net \
--to=kees.cook@canonical.com \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=linux-kernel@vger.kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.