linux-kernel - Re: [PATCH 3/4] x86: call verify

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 9 Nov 2010 12:48:57 -0800
From:	Kees Cook <kees.cook@...onical.com>
To:	Pekka Enberg <penberg@...nel.org>
Cc:	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] x86: call verify_cpu during 32bit CPU startup

Hi Pekka,

On Tue, Nov 09, 2010 at 10:28:16PM +0200, Pekka Enberg wrote:
> So why can't we do patch 2/4 XD_DISABLE clearing in
> early_init_intel()?

Because it's too late, unfortunately. I went around a few times about this
with Peter Anvin, and ultimately he agreed that it needed to go in
verify_cpu() for now.

> Why do we want to call verify_cpu() from
> arch/x86/kernel/head_32.S and not from
> arch/x86/boot/compressed/head_32.S like we do on 64-bit?

Because the longmode/SSE tests being performed in verify_cpu() need to
happen that early for 64bit. Instead of including it in two places for
32bit, we can just include it once in arch/x86/kernel/head_32.S.

-Kees

-- 
Kees Cook
Ubuntu Security Team
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/