From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-integrity@vger.kernel.org, Matthew Garrett <mjg59@google.com>
Subject: Re: Disparity in tpm pcr5 value
Date: Wed, 13 May 2020 10:59:31 -0700 [thread overview]
Message-ID: <20200513175931.xte33asq5nskjflh@cantor> (raw)
In-Reply-To: <20200513171052.GD25598@linux.intel.com>
On Wed May 13 20, Jarkko Sakkinen wrote:
>On Tue, May 05, 2020 at 03:27:31PM -0700, Jerry Snitselaar wrote:
>> On some systems we've had reports of the value of pcr5 doesn't match the digests in the tpm event log.
>> It looks like I'm able to reproduce here with 5.7-rc4 on a dell system using this parser:
>>
>> https://github.com/ValdikSS/binary_bios_measurements_parser
>>
>> Any thoughts on where to start digging? Is there another tool I should use to parse this?
>
>ExitBootServices() extends PCR5. My 1st intuition would be to look at
>final event table handling, which I documented here:
>
>https://www.kernel.org/doc/Documentation/security/tpm/tpm_event_log.rst
>
>It is somewhat quirky how it nees to be managed (had to read that
>myself to recall how it went).
>
>/Jarkko
>
Yes, my guess is the problem is that when the bios is set to use sha1 it
does not present a final events log to the os.
next prev parent reply other threads:[~2020-05-13 17:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-05 22:27 Disparity in tpm pcr5 value Jerry Snitselaar
2020-05-06 14:12 ` Ken Goldman
2020-05-07 7:35 ` Jerry Snitselaar
2020-05-07 14:50 ` Mimi Zohar
2020-05-07 16:26 ` Jerry Snitselaar
2020-05-07 20:57 ` Mimi Zohar
2020-05-07 23:12 ` Jerry Snitselaar
2020-05-13 17:10 ` Jarkko Sakkinen
2020-05-13 17:59 ` Jerry Snitselaar [this message]
2020-05-14 11:03 ` Jarkko Sakkinen
2020-05-14 16:55 ` Jerry Snitselaar
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