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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 552D4C10F14 for ; Thu, 3 Oct 2019 21:57:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2A9602086A for ; Thu, 3 Oct 2019 21:57:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730808AbfJCV5s (ORCPT ); Thu, 3 Oct 2019 17:57:48 -0400 Received: from mga02.intel.com ([134.134.136.20]:65447 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726002AbfJCV5s (ORCPT ); Thu, 3 Oct 2019 17:57:48 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Oct 2019 14:57:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.67,253,1566889200"; d="scan'208";a="195352340" Received: from okiselev-mobl1.ccr.corp.intel.com (HELO localhost) ([10.251.93.117]) by orsmga003.jf.intel.com with ESMTP; 03 Oct 2019 14:57:44 -0700 Date: Fri, 4 Oct 2019 00:57:43 +0300 From: Jarkko Sakkinen To: Mimi Zohar Cc: David Safford , linux-integrity@vger.kernel.org, stable@vger.kernel.org, David Howells , Herbert Xu , "David S. Miller" , "open list:ASYMMETRIC KEYS" , "open list:CRYPTO API" , open list Subject: Re: [PATCH] KEYS: asym_tpm: Switch to get_random_bytes() Message-ID: <20191003215743.GB30511@linux.intel.com> References: <20190926171601.30404-1-jarkko.sakkinen@linux.intel.com> <1570024819.4999.119.camel@linux.ibm.com> <20191003114119.GF8933@linux.intel.com> <1570107752.4421.183.camel@linux.ibm.com> <20191003175854.GB19679@linux.intel.com> <1570128827.5046.19.camel@linux.ibm.com> <20191003215125.GA30511@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191003215125.GA30511@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Fri, Oct 04, 2019 at 12:51:25AM +0300, Jarkko Sakkinen wrote: > On Thu, Oct 03, 2019 at 02:53:47PM -0400, Mimi Zohar wrote: > > [Cc'ing David Safford] > > > > On Thu, 2019-10-03 at 20:58 +0300, Jarkko Sakkinen wrote: > > > On Thu, Oct 03, 2019 at 09:02:32AM -0400, Mimi Zohar wrote: > > > > On Thu, 2019-10-03 at 14:41 +0300, Jarkko Sakkinen wrote: > > > > > On Wed, Oct 02, 2019 at 10:00:19AM -0400, Mimi Zohar wrote: > > > > > > On Thu, 2019-09-26 at 20:16 +0300, Jarkko Sakkinen wrote: > > > > > > > Only the kernel random pool should be used for generating random numbers. > > > > > > > TPM contributes to that pool among the other sources of entropy. In here it > > > > > > > is not, agreed, absolutely critical because TPM is what is trusted anyway > > > > > > > but in order to remove tpm_get_random() we need to first remove all the > > > > > > > call sites. > > > > > > > > > > > > At what point during boot is the kernel random pool available?  Does > > > > > > this imply that you're planning on changing trusted keys as well? > > > > > > > > > > Well trusted keys *must* be changed to use it. It is not a choice > > > > > because using a proprietary random number generator instead of defacto > > > > > one in the kernel can be categorized as a *regression*. > > > > > > > > I really don't see how using the TPM random number for TPM trusted > > > > keys would be considered a regression.  That by definition is a > > > > trusted key.  If anything, changing what is currently being done would > > > > be the regression.  > > > > > > It is really not a TPM trusted key. It trusted key that gets sealed with > > > the TPM. The key itself is used in clear by kernel. The random number > > > generator exists in the kernel to for a reason. > > > > > > It is without doubt a regression. > > > > You're misusing the term "regression" here.  A regression is something > > that previously worked and has stopped working.  In this case, trusted > > keys has always been based on the TPM random number generator.  Before > > changing this, there needs to be some guarantees that the kernel > > random number generator has a pool of random numbers early, on all > > systems including embedded devices, not just servers. > > I'm not using the term regression incorrectly here. Wrong function > was used to generate random numbers for the payload here. It is an > obvious bug. At the time when trusted keys was introduced I'd say that it was a wrong design decision and badly implemented code. But you are right in that as far that code is considered it would unfair to speak of a regression. asym-tpm.c on the other hand this is fresh new code. There has been *countless* of discussions over the years that random numbers should come from multiple sources of entropy. There is no other categorization than a bug for the tpm_get_random() there. /Jarkko