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From: Kees Cook <keescook@chromium.org>
To: Matthew Garrett <matthew.garrett@nebula.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, "x86@kernel.org" <x86@kernel.org>,
	"linux-efi@vger.kernel.org" <linux-efi@vger.kernel.org>,
	linux-security-module <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH] x86: Lock down MSR writing in secure boot
Date: Fri, 8 Feb 2013 13:02:15 -0800	[thread overview]
Message-ID: <CAGXu5jKo2PfMBO4A0ZgQcrPuj8OHNaff+CjAesOAWkZc0vB9+Q@mail.gmail.com> (raw)
In-Reply-To: <1360355671.18083.18.camel@x230.lan>

On Fri, Feb 8, 2013 at 12:34 PM, Matthew Garrett
<matthew.garrett@nebula.com> wrote:
> On Fri, 2013-02-08 at 12:28 -0800, Kees Cook wrote:
>
>> Maybe a capability isn't the right way to go, I'm not sure. I'll leave
>> that to Matthew. Whatever the flag, it should be an immutable state of
>> the boot. Though, it probably makes sense as a cap just so that
>> non-secure-boot systems can still remove it from containers, etc.
>
> There was interest in ensuring that this wasn't something special-cased
> to UEFI Secure Boot, so using a capability seemed like the most
> straightforward way - it's fundamentally a restriction on what an
> otherwise privileged user is able to do, so it seemed like it fit the
> model. But I'm not wed to it in the slightest, and in fact it causes
> problems for some userspace (anything that drops all capabilities
> suddenly finds itself unable to do something that it expects to be able
> to do), so if anyone has any suggestions for a better approach…

I don't find it unreasonable to drop all caps and lose access to
sensitive things. :) That's sort of the point, really. I think a cap
is the best match. It seems like it should either be a cap or a
namespace flag, but the latter seems messy.

-Kees

--
Kees Cook
Chrome OS Security

  reply	other threads:[~2013-02-08 21:02 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-08 19:12 Kees Cook
2013-02-08 19:17 ` H. Peter Anvin
2013-02-08 19:18   ` Kees Cook
2013-02-08 19:42     ` H. Peter Anvin
2013-02-08 20:14       ` Kees Cook
2013-02-08 20:18         ` H. Peter Anvin
2013-02-08 20:28           ` Kees Cook
2013-02-08 20:34             ` Matthew Garrett
2013-02-08 21:02               ` Kees Cook [this message]
2013-02-08 21:07                 ` Matthew Garrett
2013-02-08 21:14                   ` Josh Boyer
2013-02-08 23:09                     ` Andy Lutomirski
2013-02-08 22:30                 ` H. Peter Anvin
2013-02-08 23:06                   ` Borislav Petkov
2013-02-08 23:26                     ` Matthew Garrett
2013-02-09  1:22                       ` H. Peter Anvin
2013-02-09  1:29                         ` Matthew Garrett
2013-02-09  6:45                           ` Kees Cook
2013-02-09  9:29                             ` Borislav Petkov
2013-02-09 15:10                               ` Kees Cook
2013-02-09 15:11                               ` Matthew Garrett
2013-02-13  0:48                                 ` H. Peter Anvin
2013-02-13  5:39                                   ` Matthew Garrett
2013-02-13  6:12                                     ` H. Peter Anvin
2013-02-13  6:27                                       ` Matthew Garrett
2013-02-13  6:33                                         ` H. Peter Anvin
2013-02-13  6:41                                           ` Matthew Garrett
2013-02-13 17:20                                             ` H. Peter Anvin
2013-02-13 17:26                                               ` Matthew Garrett
2013-02-13 17:51                                                 ` Casey Schaufler
2013-02-13 17:56                                                   ` Matthew Garrett
2013-02-13 18:44                                                     ` H. Peter Anvin
2013-02-13 18:51                                                       ` Matthew Garrett
2013-02-13 22:26                                                   ` H. Peter Anvin
2013-02-13 22:58                                                     ` Casey Schaufler
2013-02-14  0:25                                                       ` H. Peter Anvin
2013-02-14  0:44                                                         ` Casey Schaufler
2013-02-14  1:04                                                           ` Matthew Garrett
2013-02-14  1:08                                                             ` H. Peter Anvin
2013-02-14  2:46                                                               ` Matthew Garrett
2013-02-14  1:34                                                             ` Casey Schaufler
2013-02-13  8:27                                           ` Paolo Bonzini
2013-02-13 17:21                                             ` H. Peter Anvin
2013-02-13 17:22                                             ` H. Peter Anvin
2013-02-13 19:55                                               ` Paolo Bonzini
2013-02-13 22:24                                                 ` H. Peter Anvin
2013-02-08 19:17 ` Matthew Garrett
2013-02-08 19:21   ` Kees Cook
2013-02-08 19:27     ` Matthew Garrett

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