Re: [PATCH v2 10/10] PM: hibernate: seal the encryption key with a PCR policy

From: Kees Cook
Date: Tue Sep 20 2022 - 19:24:30 EST


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@xxxxxxxxxx>

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@xxxxxxxxxxxxx
address.

-Kees

--
Kees Cook