From: Daniel Kiper <daniel.kiper@oracle.com>
To: james.bottomley@hansenpartnership.com, ard.biesheuvel@linaro.org
Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org, xen-devel@lists.xenproject.org,
boris.ostrovsky@oracle.com, eric.snowberg@oracle.com,
hpa@zytor.com, jgross@suse.com, konrad.wilk@oracle.com,
mingo@redhat.com, tglx@linutronix.de
Subject: Re: [PATCH v2] x86/xen/efi: Initialize UEFI secure boot state during dom0 boot
Date: Wed, 11 Apr 2018 10:56:20 +0200 [thread overview]
Message-ID: <20180411085620.GI26100@olila.local.net-space.pl> (raw)
In-Reply-To: <20180404103824.GM26100@olila.local.net-space.pl>
On Wed, Apr 04, 2018 at 12:38:24PM +0200, Daniel Kiper wrote:
> On Tue, Apr 03, 2018 at 10:00:52AM -0700, James Bottomley wrote:
> > On Tue, 2018-04-03 at 18:07 +0200, Daniel Kiper wrote:
> > > On Tue, Apr 03, 2018 at 08:44:41AM -0700, James Bottomley wrote:
>
> [...]
>
> > > > This looks like a bad idea: you're duplicating the secure boot
> > > > check in
> > > >
> > > > drivers/firmware/efi/libstub/secureboot.c
> > > >
> > > > Which is an implementation of policy. If we have to have policy in
> > > > the kernel, it should really only be in one place to prevent drift;
> > > > why can't you simply use the libstub efi_get_secureboot() so we're
> > > > not duplicating the implementation of policy?
> > >
> > > Well, here is the first version of this patch:
> > > https://lkml.org/lkml/2018/1/9/496 Ard did not like it. I was not
> > > happy too. In general both approaches are not perfect. More you can
> > > find in the discussion around this patchset. If you have better idea
> > > how to do that I am happy to implement it.
> >
> > One way might be simply to have the pre exit-boot-services code lay
> > down a variable containing the state which you pick up, rather than you
>
> Do you mean variable in kernel proper or something like that? If yes this
> is not possible. EFI Linux stub is not executed in Xen dom0. All UEFI
> infrastructure is owned and operated by Xen. Dom0 kernel can access some
> stuff in UEFI, including variables, via hypercall. However, when dom0
> runs only UEFI runtime services are available.
>
> > calling efi code separately and trying to use the insecure RT
>
> I am not sure why they are insecure.
>
> > variables. That way there's a uniform view of the internal kernel
> > secure boot state that everyone can use.
>
> That would be perfect but I have a feeling that in form proposed above
> it is not possible.
Ping?
Daniel
next prev parent reply other threads:[~2018-04-11 8:56 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-03 14:39 [PATCH v2] x86/xen/efi: Initialize UEFI secure boot state during dom0 boot Daniel Kiper
2018-04-03 15:44 ` James Bottomley
2018-04-03 16:07 ` Daniel Kiper
2018-04-03 17:00 ` James Bottomley
2018-04-04 10:38 ` Daniel Kiper
2018-04-11 8:56 ` Daniel Kiper [this message]
2018-04-16 8:15 ` Ard Biesheuvel
2018-04-16 9:04 ` Daniel Kiper
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