From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CF943C433E1 for ; Tue, 18 Aug 2020 16:27:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FF05207D3 for ; Tue, 18 Aug 2020 16:27:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726978AbgHRQ1J (ORCPT ); Tue, 18 Aug 2020 12:27:09 -0400 Received: from mga05.intel.com ([192.55.52.43]:1229 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726758AbgHRQ0d (ORCPT ); Tue, 18 Aug 2020 12:26:33 -0400 IronPort-SDR: cVIpBXoUghvrdIvWzi8odFataBRoDmuqphriX1drXuLRtgUpNjzvQ6bk7IWBLTY+d7wgXXtVYD qHof5bj3uFTQ== X-IronPort-AV: E=McAfee;i="6000,8403,9716"; a="239775987" X-IronPort-AV: E=Sophos;i="5.76,328,1592895600"; d="scan'208";a="239775987" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Aug 2020 09:26:32 -0700 IronPort-SDR: 76DfGtLTLbueqVaHMe+Z2aF+nBVb2IDPYlYjK/hGAhmikyywLpd+62x4OSJXqMsGuODKL3G1PY HD4qYqRPuHaA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,328,1592895600"; d="scan'208";a="310493054" Received: from ribnhajh-mobl.ger.corp.intel.com (HELO localhost) ([10.249.47.113]) by orsmga002.jf.intel.com with ESMTP; 18 Aug 2020 09:26:31 -0700 Date: Tue, 18 Aug 2020 19:26:30 +0300 From: Jarkko Sakkinen To: James Bottomley , Jason Gunthorpe Cc: linux-integrity@vger.kernel.org, Mimi Zohar Subject: Re: [PATCH v4 1/1] tpm: add sysfs exports for all banks of PCR registers Message-ID: <20200818162630.GE137138@linux.intel.com> References: <20200817213506.4474-1-James.Bottomley@HansenPartnership.com> <20200817213506.4474-2-James.Bottomley@HansenPartnership.com> <20200818161207.GC137138@linux.intel.com> <20200818161955.GD137138@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200818161955.GD137138@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Tue, Aug 18, 2020 at 07:19:57PM +0300, Jarkko Sakkinen wrote: > On Tue, Aug 18, 2020 at 07:12:09PM +0300, Jarkko Sakkinen wrote: > > On Mon, Aug 17, 2020 at 02:35:06PM -0700, James Bottomley wrote: > > > Create sysfs per hash groups with 24 PCR files in them one group, > > > named pcr-, for each agile hash of the TPM. The files are > > > plugged in to a PCR read function which is TPM version agnostic, so > > > this works also for TPM 1.2 but the hash is only sha1 in that case. > > > > > > Note: the macros used to create the hashes emit spurious checkpatch > > > warnings. Do not try to "fix" them as checkpatch recommends, otherwise > > > they'll break. > > > > > > Signed-off-by: James Bottomley > > > Reviewed-by: Jerry Snitselaar > > > Tested-by: Thiago Jung Bauermann > > > > I have hard time understanding why this is required. > > > > You can grab the information through /dev/tpm0 just fine. > > I just think it is principally wrong to add sysfs files if they don't > have any measurable value other than perhaps some convenience. > > It is trival to write only a libc dependent program that outputs PCRs. > > I think this is essentially an user space problem that is getting sorted > out with kernel code. Jason, what do you make of this? I recall that it was you who I discussed with about this topic when TPM 2.0 support was first upstreamed. /Jarkko