linux-kernel - Re: [PATCH v2 2/3] efi: call get_event

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Message-ID: <20170914184126.eevnstwq3i6fiq4j@linux.intel.com>
Date:   Thu, 14 Sep 2017 11:43:28 -0700
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Thiebaud Weksteen <tweek@...gle.com>
Cc:     linux-efi@...r.kernel.org, ard.biesheuvel@...aro.org,
        matt@...eblueprint.co.uk, linux-kernel@...r.kernel.org,
        mjg59@...gle.com, tpmdd-devel@...ts.sourceforge.net,
        peterhuewe@....de, jgunthorpe@...idianresearch.com,
        tpmdd@...horst.net
Subject: Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices

On Mon, Sep 11, 2017 at 12:00:21PM +0200, Thiebaud Weksteen wrote:
> With TPM 2.0 specification, the event logs may only be accessible by
> calling an EFI Boot Service. Modify the EFI stub to copy the log area to
> a new Linux-specific EFI configuration table so it remains accessible
> once booted.
> 
> When calling this service, it is possible to specify the expected format
> of the logs: TPM 1.2 (SHA1) or TPM 2.0 ("Crypto Agile"). For now, only the
> first format is retrieved.
> 
> Signed-off-by: Thiebaud Weksteen <tweek@...gle.com>

With a quick skim the code change looks good but I remember from
Matthew's talk that there was this issue that ExitBootServices() would
cause a yet another event?

I guess you could manually synthetize that event by reading the PCR
values right after ExitBootServices()?

Anyway, great work, thanks for making this effort.

/Jarkko