From: Matthew Garrett <mjg59@srcf.ucam.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org
Subject: Re: [PATCH 07/11] kexec: Disable in a secure boot environment
Date: Tue, 4 Sep 2012 22:27:17 +0100 [thread overview]
Message-ID: <20120904212717.GA30899@srcf.ucam.org> (raw)
In-Reply-To: <87r4qhwkx9.fsf@xmission.com>
On Tue, Sep 04, 2012 at 02:13:54PM -0700, Eric W. Biederman wrote:
> Matthew Garrett <mjg59@srcf.ucam.org> writes:
> > And
> > secondly, there are already several non-EFI platforms that want to enact
> > a policy preventing root from being able to arbitrarily replace the
> > kernel. Given that people are doing this in the wild, it makes sense to
> > move towards offering that policy in the mainline kernel.
>
> Either this code makes sense without an appeal to EFI or this code makes
> no sense.
The driving force behind this code right now is that our choices are
either (1) do something like this, or (2) disable kexec entirely. Like I
said, long term we'd want to provide appropriate technical mechanisms to
make kexec usable in a world where people want to be able to trust their
kernel, and we have people working on that. But that being our
motivation for the implementation doesn't mean that other parties won't
have uses for it, and I'd like to find a solution that satisfies them as
well.
> It is fine for jumping through the EFI trusted boot hoops to be your
> motivation, but EFI policy should not be the justification for kernel
> implementation details.
Sure it is. The kernel exists to provide the functionality that people
require, and UEFI imposes that requirement on the people. It's like
saying gcc policy shouldn't be the justification for kernel
implementation details. We don't control the gcc developers, but we have
to consume what they provide us with.
> So please rework this to come from an angle that makes sense all by
> itself.
I'm afraid I have no idea what you're asking for here. Some vendors want
to be able to ensure that kexec is only used to load trusted code. Right
now there's no mechanism for ensuring that, so why not at least provide
a mechanism for them to turn it off at runtime?
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2012-09-04 21:27 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-04 15:55 [RFC] First attempt at kernel secure boot support Matthew Garrett
2012-09-04 15:55 ` [PATCH 01/11] Secure boot: Add new capability Matthew Garrett
2012-09-04 15:55 ` [PATCH 02/11] PCI: Lock down BAR access in secure boot environments Matthew Garrett
2012-10-01 21:00 ` Pavel Machek
2012-09-04 15:55 ` [PATCH 03/11] x86: Lock down IO port " Matthew Garrett
2012-09-04 16:16 ` Alan Cox
2012-09-04 16:16 ` Matthew Garrett
2012-09-04 15:55 ` [PATCH 04/11] ACPI: Limit access to custom_method Matthew Garrett
2012-09-04 15:55 ` [PATCH 05/11] asus-wmi: Restrict debugfs interface Matthew Garrett
2012-09-04 16:12 ` Alan Cox
2012-09-04 16:13 ` Matthew Garrett
2012-09-04 15:55 ` [PATCH 06/11] Restrict /dev/mem and /dev/kmem in secure boot setups Matthew Garrett
2012-09-04 15:55 ` [PATCH 07/11] kexec: Disable in a secure boot environment Matthew Garrett
2012-09-04 20:13 ` Eric W. Biederman
2012-09-04 20:22 ` Matthew Garrett
2012-09-04 21:13 ` Eric W. Biederman
2012-09-04 21:27 ` Matthew Garrett [this message]
2012-09-04 22:12 ` Eric W. Biederman
2012-09-04 23:25 ` Matthew Garrett
2012-09-05 4:33 ` Eric W. Biederman
2012-09-05 5:16 ` Matthew Garrett
2012-09-05 7:00 ` Eric W. Biederman
2012-09-05 7:03 ` Matthew Garrett
2012-09-04 21:39 ` Alan Cox
2012-09-04 21:40 ` Matthew Garrett
2012-09-05 15:43 ` Roland Eggner
2012-09-05 15:46 ` Matthew Garrett
2012-09-05 21:13 ` Mimi Zohar
2012-09-05 21:41 ` Matthew Garrett
2012-09-05 21:49 ` Eric Paris
2012-09-04 15:55 ` [PATCH 08/11] Secure boot: Add a dummy kernel parameter that will switch on Secure Boot mode Matthew Garrett
2012-09-04 15:55 ` [PATCH 09/11] efi: Enable secure boot lockdown automatically when enabled in firmware Matthew Garrett
2012-09-04 15:55 ` [PATCH 10/11] acpi: Ignore acpi_rsdp kernel parameter in a secure boot environment Matthew Garrett
2012-09-04 16:30 ` Shuah Khan
2012-09-04 16:38 ` Matthew Garrett
2012-09-04 16:44 ` Shuah Khan
2012-09-04 20:37 ` Alan Cox
2012-09-04 20:37 ` Matthew Garrett
2012-09-04 20:50 ` Josh Boyer
2012-09-04 15:55 ` [PATCH 11/11] SELinux: define mapping for new Secure Boot capability Matthew Garrett
2012-09-04 16:08 ` [RFC] First attempt at kernel secure boot support Alan Cox
2012-09-04 16:12 ` Matthew Garrett
2012-10-01 21:07 ` Pavel Machek
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