From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Ken Goldman <kgold@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
tpmdd-devel@lists.sourceforge.net, keyrings@vger.kernel.org,
linux-ima-devel@lists.sourceforge.net
Subject: Re: [tpmdd-devel] [Linux-ima-devel] [PATCH v3 0/6] Updated API for TPM 2.0 PCR extend
Date: Wed, 05 Jul 2017 12:06:42 -0400 [thread overview]
Message-ID: <1499270802.3059.101.camel@linux.vnet.ibm.com> (raw)
In-Reply-To: <55cf0a07-bee8-a034-4d40-6232bc0eefb8@linux.vnet.ibm.com>
On Wed, 2017-07-05 at 11:18 -0400, Ken Goldman wrote:
> On 6/28/2017 1:28 PM, Jarkko Sakkinen wrote:
> > 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:
> >>> 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.
>
> This is true - one getcap to determine the number of algorithms, then a
> pcr read, then parse the response structures and match the algorithms to
> sizes.
>
> Alternatively, could you create a table mapping the algorithm to the
> size? There are currently 8 approved algorithms, meaning the table is
> 32 bytes, probably less code than the queries.
>
> As for an algorithm appearing in the TPM that's not in the table, it
> takes a year or more for a new algorithm to appear. Is that enough time
> to patch the device driver?
>
> FYI, the 8 algorithms are:
>
> sha1, sha256, sha384, sha512, sm3-256, sha3-256, sha3-384, sha3-512.
>
> I am only aware of sha1, sha256, and sm3-256 being used in production
> hardware TPMs.
New devices aren't being shipped with the most recent kernels. So
even if the upstream kernel supports the newer crypto algorithms, that
doesn't imply that it is available.
A safer method would be to query the TPM for the digest sizes.
Mimi
prev parent reply other threads:[~2017-07-05 16:09 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
2017-06-28 22:28 ` Mimi Zohar
2017-07-05 15:18 ` [tpmdd-devel] " Ken Goldman
2017-07-05 16:06 ` Mimi Zohar [this message]
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