Messages in this thread | | | Date | Sat, 6 Apr 2019 11:30:47 -0400 | From | Sasha Levin <> | Subject | Re: [PATCH 2/2] ftpm: firmware TPM running in TEE |
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On Wed, Apr 03, 2019 at 09:27:28PM +0300, Jarkko Sakkinen wrote: >On Wed, Apr 03, 2019 at 09:18:27PM +0300, Jarkko Sakkinen wrote: >> On Tue, Apr 02, 2019 at 03:33:16PM -0400, Sasha Levin wrote: >> > This patch adds support for a software-only implementation of a TPM >> > running in TEE. >> > >> > There is extensive documentation of the design here: >> > https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ . >> > >> > As well as reference code for the firmware available here: >> > https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM >> > >> > Signed-off-by: Thirupathaiah Annapureddy <thiruan@microsoft.com> >> > Signed-off-by: Sasha Levin <sashal@kernel.org> >> >> What is the context anyway? I mean tpm_crb already supports fTPM running >> in TZ. > >Might take 2-3 weeks before I have time to go through ftpm1.pdf with >full concentration. I did search through the PDF for CRB and found >zero hits.
The fTPM as described in that paper and implemented in practice does not use the CRB interface, thus we can't use tpm_crb to interface with the firmware TPM.
>The commit message should absolutely better explain what is going on >and preferably there should be some more broad documentation in >Documentation/security/tpm.
The code itself is just a small shim between the firmware TPM and the kernel's TPM interface. There's really not much else to expand on in the commit log.
I'll add some background to Documentation/security/tpm.
>Now this is just a random code dump and nothing else.
It pretty much is, but that's because this is just a "stupid" shim, there heavy lifting is done outside of the kernel.
>Also, I have zero idea how to test this. Any recommendations on ARM >board that can be easily used to test custom TZ applications would be >nice.
We are testing this on a Broadcom's Stingray SST100 board, and if you have one we can help out with setting up a test environment. Otherwise, we haven't really tried it on other boards.
-- Thanks, Sasha
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