linux-kernel - Re: new cmdline parameter disable_cpu

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <20160104231633.GA15949@pd.tnic>
Date:	Tue, 5 Jan 2016 00:16:33 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Piotr Dąbrowski <ultr@...r.pl>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: new cmdline parameter disable_cpu_features= (microcode update?)

On Mon, Jan 04, 2016 at 11:55:57PM +0100, Piotr Dąbrowski wrote:
> Is such thing even possible? And would it be a reasonable thing to do
> (maybe the rest of the microcode would break badly without the factory
> flags set)?

You cannot change the microcode patches - they're supplied by the CPU
vendors as is and are signed/encrypted.

In an ideal world, we should have BIOS disable options for all CPU
features which could turn out to be problematic so that the user remains
in control. Without the need to be applying microcode patches even.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--
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/