From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Ard Biesheuvel <ardb@kernel.org>
Cc: Daniel Kiper <daniel.kiper@oracle.com>,
Alec Brown <alec.r.brown@oracle.com>,
Kanth Ghatraju <kanth.ghatraju@oracle.com>,
Ross Philipson <ross.philipson@oracle.com>,
"dpsmith@apertussolutions.com" <dpsmith@apertussolutions.com>,
"piotr.krol@3mdeb.com" <piotr.krol@3mdeb.com>,
"krystian.hebel@3mdeb.com" <krystian.hebel@3mdeb.com>,
"persaur@gmail.com" <persaur@gmail.com>,
"Yoder, Stuart" <stuart.yoder@arm.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
"michal.zygowski@3mdeb.com" <michal.zygowski@3mdeb.com>,
James Bottomley <James.Bottomley@hansenpartnership.com>,
"lukasz@hawrylko.pl" <lukasz@hawrylko.pl>,
linux-efi <linux-efi@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
The development of GNU GRUB <grub-devel@gnu.org>,
Kees Cook <keescook@chromium.org>
Subject: Re: Linux DRTM on UEFI platforms
Date: Wed, 30 Mar 2022 08:27:55 +0100 [thread overview]
Message-ID: <20220330072755.GA1169@srcf.ucam.org> (raw)
In-Reply-To: <CAMj1kXHfw75GphiewQzbA-swsMD3AGunyhc9HSue_xqrHt9GhQ@mail.gmail.com>
On Wed, Mar 30, 2022 at 09:23:17AM +0200, Ard Biesheuvel wrote:
> On Wed, 30 Mar 2022 at 09:19, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> > From a conceptual perspective we've thought of the EFI stub as being
> > logically part of the bootloader rather than the early kernel, and the
> > bootloader is a point where the line is drawn. My guy feeling is that
> > jumping into the secure kernel environment before EBS has been called is
> > likely to end badly.
>
> If you jump back into the system firmware, sure.
>
> But the point I was trying to make is that you can replace that with
> your own minimal implementation of EFI that just exposes a memory map
> and some protocols and nothing else, and then the secure launch kernel
> would be entirely in charge of the execution environment.
We can't just replace system firmware with an imitation of the same -
for instance, configuring the cold boot prevention memory overwrite
requires us to pass a variable through to the real firmware, and that's
something that we do in the stub.
next prev parent reply other threads:[~2022-03-30 7:28 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-29 17:40 Linux DRTM on UEFI platforms Matthew Garrett
2022-03-30 7:02 ` Ard Biesheuvel
2022-03-30 7:11 ` Matthew Garrett
2022-03-30 7:12 ` Ard Biesheuvel
2022-03-30 7:18 ` Matthew Garrett
2022-03-30 7:23 ` Ard Biesheuvel
2022-03-30 7:27 ` Matthew Garrett [this message]
2022-03-30 7:39 ` Ard Biesheuvel
2022-03-30 12:46 ` James Bottomley
2022-03-31 0:35 ` Daniel P. Smith
2022-03-31 7:13 ` Ard Biesheuvel
2022-03-31 10:59 ` Heinrich Schuchardt
2022-05-19 20:57 ` Daniel P. Smith
2022-05-19 20:57 ` Daniel P. Smith
2022-06-10 16:40 ` Ard Biesheuvel
2022-07-05 18:35 ` Daniel P. Smith
2022-07-06 0:03 ` Brendan Trotter
2022-07-06 0:12 ` Matthew Garrett
2022-07-07 9:46 ` Daniel P. Smith
2022-07-08 3:36 ` Brendan Trotter
2022-07-08 4:56 ` Matthew Garrett
2022-07-22 17:23 ` Daniel P. Smith
2022-07-23 5:15 ` Brendan Trotter
2022-08-09 10:53 ` Daniel P. Smith
2022-08-10 9:07 ` Brendan Trotter
2022-08-10 17:46 ` Matthew Garrett
2022-08-11 9:55 ` Brendan Trotter
2022-08-11 11:34 ` Daniel Kiper
2022-08-11 18:25 ` Matthew Garrett
2022-08-12 3:22 ` Brendan Trotter
2022-08-12 5:54 ` Matthew Garrett
2022-08-05 12:53 ` Ard Biesheuvel
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