linux-kernel - RE: [PATCH v7 1/2] fTPM: firmware TPM running in TEE

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Message-ID: <CY4PR21MB027937ADCEBF85826FF3516FBCF50@CY4PR21MB0279.namprd21.prod.outlook.com>
Date:   Fri, 5 Jul 2019 02:40:56 +0000
From:   Thirupathaiah Annapureddy <thiruan@...rosoft.com>
To:     Ilias Apalodimas <ilias.apalodimas@...aro.org>
CC:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Sasha Levin <sashal@...nel.org>,
        "peterhuewe@....de" <peterhuewe@....de>,
        "jgg@...pe.ca" <jgg@...pe.ca>, "corbet@....net" <corbet@....net>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-doc@...r.kernel.org" <linux-doc@...r.kernel.org>,
        "linux-integrity@...r.kernel.org" <linux-integrity@...r.kernel.org>,
        Microsoft Linux Kernel List <linux-kernel@...rosoft.com>,
        "Bryan Kelly (CSI)" <bryankel@...rosoft.com>,
        "tee-dev@...ts.linaro.org" <tee-dev@...ts.linaro.org>,
        "sumit.garg@...aro.org" <sumit.garg@...aro.org>,
        "rdunlap@...radead.org" <rdunlap@...radead.org>,
        Joakim Bech <joakim.bech@...aro.org>
Subject: RE: [PATCH v7 1/2] fTPM: firmware TPM running in TEE



> -----Original Message-----
> From: Ilias Apalodimas <ilias.apalodimas@...aro.org>
> Sent: Thursday, July 4, 2019 11:11 AM
> To: Thirupathaiah Annapureddy <thiruan@...rosoft.com>
> Cc: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>; Sasha Levin
> <sashal@...nel.org>; peterhuewe@....de; jgg@...pe.ca; corbet@....net; linux-
> kernel@...r.kernel.org; linux-doc@...r.kernel.org; linux-
> integrity@...r.kernel.org; Microsoft Linux Kernel List <linux-
> kernel@...rosoft.com>; Bryan Kelly (CSI) <bryankel@...rosoft.com>; tee-
> dev@...ts.linaro.org; sumit.garg@...aro.org; rdunlap@...radead.org; Joakim Bech
> <joakim.bech@...aro.org>
> Subject: Re: [PATCH v7 1/2] fTPM: firmware TPM running in TEE
> 
> Hi Thirupathaiah,
> [...]
> > > > > > I managed to do some quick testing in QEMU.
> > > > > > Everything works fine when i build this as a module (using IBM's TPM
> 2.0
> > > > > > TSS)
> > > > > >
> > > > > > - As module
> > > > > > # insmod /lib/modules/5.2.0-
> rc1/kernel/drivers/char/tpm/tpm_ftpm_tee.ko
> > > > > > # getrandom -by 8
> > > > > > randomBytes length 8
> > > > > > 23 b9 3d c3 90 13 d9 6b
> > > > > >
> > > > > > - Built-in
> > > > > > # dmesg | grep optee
> > > > > > ftpm-tee firmware:optee: ftpm_tee_probe:tee_client_open_session
> failed,
> > > > > > err=ffff0008
> > > > > This (0xffff0008) translates to TEE_ERROR_ITEM_NOT_FOUND.
> > > > >
> > > > > Where is fTPM TA located in the your test setup?
> > > > > Is it stitched into TEE binary as an EARLY_TA or
> > > > > Is it expected to be loaded during run-time with the help of user mode
> OP-
> > > TEE supplicant?
> > > > >
> > > > > My guess is that you are trying to load fTPM TA through user mode OP-
> TEE
> > > supplicant.
> > > > > Can you confirm?
> > > > I tried both
> > > >
> > >
> > > Ok apparently there was a failure with my built-in binary which i
> > > didn't notice. I did a full rebuilt and checked the elf this time :)
> > >
> > > Built as an earlyTA my error now is:
> > > ftpm-tee firmware:optee: ftpm_tee_probe:tee_client_open_session
> > > failed, err=ffff3024 (translates to TEE_ERROR_TARGET_DEAD)
> > > Since you tested it on real hardware i guess you tried both
> > > module/built-in. Which TEE version are you using?
> >
> > I am glad that the first issue (TEE_ERROR_ITEM_NOT_FOUND) is resolved after
> stitching
> > fTPM TA as an EARLY_TA.
> >
> > Regarding TEE_ERROR_TARGET_DEAD error, may I know which HW platform you are
> using to test?
> 
> QEMU, on armv7
> 
> > What is the preboot environment (UEFI or U-boot)?
> > Where is the secure storage in that HW platform?
> > I could think of two classes of secure storage.
> > 1. UFS/eMMC RPMB : If Supplicant in U-boot/UEFI initializes the
> > fTPM TA NV Storage, there should be no issue.
> > If fTPM TA NV storage is not initialized in pre-boot environment and you are
> using
> > built-in fTPM Linux driver, you can run into this issue as TA will try to
> initialize
> > NV store and fail.
> >
> > 2. other storage devices like QSPI accessible to only secure mode after
> > EBS/ReadyToBoot mile posts during boot. In this case, there should be no
> issue at all
> > as there is no dependency on non-secure side services provided by supplicant.
> >
> 
> Please check the previous mail from Sumit. It explains exaclty what's going on.
> The tl;dr version is that the storage is up only when the supplicant is
> running.

I definitely know that OP-TEE can access storage only when the "user mode" supplicant 
is running :). But fTPM NV storage should have been initialized in 
in the preboot environment (UEFI/U-boot). 

It would also be helpful to understand the overall use case/scenario (Measured boot?)you
are trying to exercise with the fTPM. 

I also want to emphasize that this discussion is turning into more of how 
fTPM gets integrated/enabled in a new HW platform.  
fTPM is hosted in github and you definitely bring any issues/feature requests there. 


> 
> > If you let me know the HW platform details, I am happy to work with you to
> enable/integrate
> > fTPM TA on that HW platform.
> >
> Thanks,
> The hardware i am waiting for for has an eMMC RPMB. In theory the U-Boot
> supplicant support will be there so i'll be able to test it.
Can you give me the details of HW so that I can order one for myself? 
Is it one of the 96boards? 
The reason for the ask is that we have not upstreamd u-boot fTPM stack yet, 
although we have future plans for it. 

--Thiru