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Date:   Tue, 20 Sep 2022 16:24:22 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Evan Green <evgreen@chromium.org>
Cc:     linux-kernel@vger.kernel.org, gwendal@chromium.org,
        Eric Biggers <ebiggers@kernel.org>,
        Matthew Garrett <mgarrett@aurora.tech>, jarkko@kernel.org,
        zohar@linux.ibm.com, linux-integrity@vger.kernel.org,
        Pavel Machek <pavel@ucw.cz>, apronin@chromium.org,
        dlunev@google.com, rjw@rjwysocki.net, linux-pm@vger.kernel.org,
        corbet@lwn.net, jejb@linux.ibm.com, Hao Wu <hao.wu@rubrik.com>,
        Len Brown <len.brown@intel.com>,
        Matthew Garrett <matthewgarrett@google.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>, axelj <axelj@axis.com>
Subject: Re: [PATCH v2 10/10] PM: hibernate: seal the encryption key with a
 PCR policy
Message-ID: <202209201620.A886373@keescook>
References: <20220823222526.1524851-1-evgreen@chromium.org>
 <20220823152108.v2.10.Ifce072ae1ef1ce39bd681fff55af13a054045d9f@changeid>
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On Tue, Aug 23, 2022 at 03:25:26PM -0700, Evan Green wrote:
> The key blob is not secret, and by default the TPM will happily unseal
> it regardless of system state. We can protect against that by sealing
> the secret with a PCR policy - if the current PCR state doesn't match,
> the TPM will refuse to release the secret. For now let's just seal it to
> PCR 23. In the long term we may want a more flexible policy around this,
> such as including PCR 7 for PCs or 0 for Chrome OS.
> 
> Sourced-from: Matthew Garrett <mjg59@google.com>

If it's a total rewrite, I'd say use:

Suggested-by: Matthew Garrett <...>
Link: https://lore.kernel.org/of/what/it/was/based/on

If it's built on an existing patch, I'd say use:

Co-developed-by: Matthew Garrett <...>
Signed-off-by: Matthew Garrett <...>

But I defer to what Matthew thinks. :)

Also, if you don't hear from Matthew, maybe ping his mjg59@srcf.ucam.org
address.

-Kees

-- 
Kees Cook