From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>,
linux-ima-devel@lists.sourceforge.net,
linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net, keyrings@vger.kernel.org,
linux-kernel@vger.kernel.org,
Kenneth Goldman <kgoldman@us.ibm.com>
Subject: Re: [Linux-ima-devel] [PATCH v3 0/6] Updated API for TPM 2.0 PCR extend
Date: Wed, 28 Jun 2017 20:28:51 +0300 [thread overview]
Message-ID: <20170628172851.fuap4ennmdj473yu@linux.intel.com> (raw)
In-Reply-To: <1498480439.3387.45.camel@linux.vnet.ibm.com>
On Mon, Jun 26, 2017 at 08:33:59AM -0400, Mimi Zohar wrote:
> On Sat, 2017-06-24 at 11:03 +0200, Jarkko Sakkinen wrote:
> > On Wed, Jun 21, 2017 at 04:29:35PM +0200, Roberto Sassu wrote:
>
>
> > To move this forward and be more constructive here's how I see it
> > should be done (along the lines, draft):
> >
> > int tpm_pcr_extend(u32 chip_num, int pcr_idx, unsigned int alg,
> > const u8 *hash);
> >
> > The paramater 'alg' is crypto ID as specified by crypto subsystem.
>
> Based on Kenneth Goldman's input, the new IMA TPM-2.0 crypto hash
> agile measurement list will contain the TPM crypto hash algorithm ids
> (TPM crypto-ID).
Doesn't this lock you to TPM?
If you seriously want to do this, I guess it is fine by me but I'm just
wondering why the measurement list couldn't use something with more
loose binding to TPM.
> > TPM driver must have a precompiled table of mappings for crypto IDs
> > and TPM algorithm IDs.
>
> We could map the TPM crypto-IDs to the crypto subsystem IDs and then
> map them back, but is that necessary?
>
> >
> > In addition it must have dynamically acquired list of TPM alg IDs.
> > For those algs that static mapping does not exist it must extend
> > them like we do now everything else except SHA-1 (Naynas changes).
>
> Padding/truncating an unknown bank using SHA1 is fine, but at some
> point, as Roberto pointed out to me, TPM 2.0's might not support SHA-
> 1. So for the record, we're hard coding the use of SHA1 for the
> unknown algorithms whether or not the TPM supports SHA1.
Why doesn't it work to pick algorithm X from the availabe options and
do truncation/padding for that? Not necessarily SHA1.
>
> > There's absolutely no need to pass digest size like you do BTW as it is
> > defined by the standard.
>
> For algorithms known to the crypto subsystem, that is fine, but for
> the unknown TPM crypto algorithms, we would need to somehow query the
> TPM for the digest sizes to create the mapping.
>
> Mimi
There's a TPM command to query TPM algorithms.
/Jarkko
next prev parent reply other threads:[~2017-06-28 17:29 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 14:29 [PATCH v3 0/6] Updated API for TPM 2.0 PCR extend Roberto Sassu
2017-06-21 14:29 ` [PATCH v3 1/6] tpm: use tpm_buf functions to perform a PCR read Roberto Sassu
2017-06-22 10:14 ` [tpmdd-devel] " Jarkko Sakkinen
2017-06-22 11:54 ` Roberto Sassu
2017-06-23 10:56 ` Jarkko Sakkinen
2017-06-21 14:29 ` [PATCH v3 2/6] tpm: use tpm2_pcr_read_tpm_buf() in tpm2_do_selftest() Roberto Sassu
2017-06-23 9:55 ` [tpmdd-devel] " Jarkko Sakkinen
2017-06-23 10:22 ` Roberto Sassu
2017-06-21 14:29 ` [PATCH v3 3/6] tpm: introduce tpm_pcr_bank_info structure with digest_size from TPM Roberto Sassu
2017-06-23 10:26 ` Jarkko Sakkinen
2017-06-23 11:25 ` Roberto Sassu
2017-06-27 15:24 ` [tpmdd-devel] " Mimi Zohar
2017-06-21 14:29 ` [PATCH v3 4/6] tpm: replace TPM algorithms IDs with tpm_pcr_bank_info structs in tpm_chip Roberto Sassu
2017-06-23 10:32 ` Jarkko Sakkinen
2017-06-21 14:29 ` [PATCH v3 5/6] tpm: introduce tpm_get_pcr_banks_info() Roberto Sassu
2017-06-23 10:35 ` Jarkko Sakkinen
2017-06-21 14:29 ` [PATCH v3 6/6] tpm: pass multiple digests to tpm_pcr_extend() Roberto Sassu
2017-06-23 10:37 ` [tpmdd-devel] " Jarkko Sakkinen
2017-06-24 9:03 ` [PATCH v3 0/6] Updated API for TPM 2.0 PCR extend Jarkko Sakkinen
2017-06-26 6:58 ` Roberto Sassu
2017-06-26 7:21 ` Roberto Sassu
2017-06-28 17:10 ` Jarkko Sakkinen
2017-06-26 12:33 ` [Linux-ima-devel] " Mimi Zohar
2017-06-26 14:56 ` Roberto Sassu
2017-06-26 17:12 ` Mimi Zohar
2017-06-28 17:28 ` Jarkko Sakkinen [this message]
2017-06-28 22:28 ` Mimi Zohar
2017-07-05 15:18 ` [tpmdd-devel] " Ken Goldman
2017-07-05 16:06 ` Mimi Zohar
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