Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices

From	Matthew Garrett <mjg59@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices
Date	2017-09-14 20:50 +0200
Message-ID	<upHn4-e8-5@gated-at.bofh.it> (permalink)
References	<uotPb-1xj-3@gated-at.bofh.it> <uotPb-1xj-1@gated-at.bofh.it> <upHn4-e8-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Sep 14, 2017 at 11:43 AM, Jarkko Sakkinen
<jarkko.sakkinen@linux.intel.com> wrote:
> 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@google.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()?

I think that would involve breaking SHA1… the information should be
available in the TCG_TREE_FINAL_EVENTS configuration table, so it
/should/ just be a matter of merging the events from that into the
event log.

Thread

[PATCH v2 2/3] efi: call get_event_log before ExitBootServices Thiebaud Weksteen <tweek@google.com> - 2017-09-11 12:10 +0200
  Re: [tpmdd-devel] [PATCH v2 2/3] efi: call get_event_log before  ExitBootServices Javier Martinez Canillas <javierm@redhat.com> - 2017-09-14 12:30 +0200
    Re: [tpmdd-devel] [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Thiebaud Weksteen <tweek@google.com> - 2017-09-18 14:20 +0200
      Re: [tpmdd-devel] [PATCH v2 2/3] efi: call get_event_log before  ExitBootServices Javier Martinez Canillas <javierm@redhat.com> - 2017-09-18 14:50 +0200
  Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Matthew Garrett <mjg59@google.com> - 2017-09-14 20:50 +0200
    Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-09-14 21:10 +0200
      Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-09-15 06:10 +0200
      Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Thiebaud Weksteen <tweek@google.com> - 2017-09-18 14:30 +0200
        Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-09-18 20:00 +0200
  Re: [PATCH v2 2/3] efi: call get_event_log before ExitBootServices Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> - 2017-09-14 20:50 +0200

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