From: Jerry Snitselaar <jsnitsel@redhat.com>
To: Ken Goldman <kgold@linux.ibm.com>
Cc: linux-integrity@vger.kernel.org,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Matthew Garrett <mjg59@google.com>,
Ken Goldman <kgoldman@us.ibm.com>,
Mimi Zohar <zohar@linux.ibm.com>
Subject: Re: Disparity in tpm pcr5 value
Date: Thu, 7 May 2020 00:35:48 -0700 [thread overview]
Message-ID: <20200507073548.zpyv3u7rv3u7jqrs@cantor> (raw)
In-Reply-To: <4b3be2e9-35f7-d730-8e3b-b252ba5cb095@linux.ibm.com>
On Wed May 06 20, Ken Goldman wrote:
>On 5/5/2020 6:27 PM, 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?
>
>If you email me the event log in binary, I can run it through the IBM
>calculator and see if I get the same error.
>
>
A couple other data points:
- On the Dell system where I did this if I change it in the bios to use sha256
instead of sha1, then using tsseventextend to parse matches the value in the tpm.
In the sha256 case there is a final events log.
- I have a nuc5 here, which also extends into sha1, and the parse matches there.
- Javier has also reproduced it when passing through swtpm to a vm.
- I added some debugging code, and there is nothing extending pcr5 with tpm_pcr_extend.
- Ken's parse of the log also shows the disparity, which I've now done as well with
the tpm1.2 version of the tsseventextend tool.
next prev parent reply other threads:[~2020-05-07 7:36 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 [this message]
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
2020-05-14 11:03 ` Jarkko Sakkinen
2020-05-14 16:55 ` Jerry Snitselaar
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