From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mimi Zohar Subject: Re: [Linux-ima-devel] [PATCH 0/4] Extend TPM 2.0 PCR banks each with corresponding digest Date: Wed, 05 Apr 2017 08:24:12 -0400 Message-ID: <1491395052.2898.4.camel@linux.vnet.ibm.com> References: <20170329102452.32212-1-roberto.sassu@huawei.com> <20170405121617.kpdrtuhb5ipj33ea@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170405121617.kpdrtuhb5ipj33ea-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tpmdd-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org To: Jarkko Sakkinen , Roberto Sassu Cc: linux-ima-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: tpmdd-devel@lists.sourceforge.net Hi Jarkko, On Wed, 2017-04-05 at 15:16 +0300, Jarkko Sakkinen wrote: > On Wed, Mar 29, 2017 at 12:24:48PM +0200, Roberto Sassu wrote: > > tpm_pcr_extend() was originally designed to extend a TPM 1.2 PCR with > > a SHA1 digest. With TPM 2.0, multiple hash algorithms can be supported, > > but, at the moment, only one digest can be passed to the function. > > > > Since TCG mandates that all PCR banks must be extended, commit c1f92b4 > > (tpm: enhance TPM 2.0 PCR extend to support multiple banks) filled > > the gap by padding the SHA1 digest passed to tpm_pcr_extend(), to extend > > remaining PCR banks. > > > > This patch set adds support for providing a digest for each PCR bank. > > > > The first patch adds an additional check to tpm2_pcr_extend() to ensure > > that all digests have been provided (to meet TCG specs). > > > > The second patch provides a mechanism for TPM users to convert a TPM > > algorithm ID to a crypto ID and vice-versa, so that they can calculate > > the digest of an event data by using the crypto subsystem. > > > > The third patch allows TPM users to know which hash algorithms the TPM > > supports. Since the limit of active banks is fixed (the size of the > > active_banks array in the tpm_chip structure), the new function > > tpm_pcr_algorithms() accepts as input a sized array. > > > > The fourth patch introduces tpm_pcr_extend_digests(), which accepts > > as input a sized array of tpm2_digest structures. Each array element > > contains the algorithm and the digest for a PCR bank. > > I don't understand why you are making these changes and why put the > commit messages in the cover letter and not in the commits where you > merely have the short summary. These patches are prereqs for IMA to extend multiple TPM banks directly and include multiple hashes in the IMA measurement list. Mimi > With the given information I'm not taking any of this. If we with > more information these somehow make sense please remove the commit > messages from the cover letter and write proper one to the commits. > Just explain in plain english what the heck you are doing... ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot