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 0F2C6CA9ECB for ; Thu, 31 Oct 2019 21:03:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D93C9218DE for ; Thu, 31 Oct 2019 21:03:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729820AbfJaVDg (ORCPT ); Thu, 31 Oct 2019 17:03:36 -0400 Received: from mga02.intel.com ([134.134.136.20]:34915 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727742AbfJaVDg (ORCPT ); Thu, 31 Oct 2019 17:03:36 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Oct 2019 14:03:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,253,1569308400"; d="scan'208";a="194457177" Received: from epobrien-mobl1.ger.corp.intel.com (HELO localhost) ([10.252.10.103]) by orsmga008.jf.intel.com with ESMTP; 31 Oct 2019 14:03:31 -0700 Date: Thu, 31 Oct 2019 23:03:30 +0200 From: Jarkko Sakkinen To: James Bottomley Cc: "Safford, David (GE Global Research, US)" , Ken Goldman , Mimi Zohar , "linux-integrity@vger.kernel.org" , "stable@vger.kernel.org" , "open list:ASYMMETRIC KEYS" , "open list:CRYPTO API" , open list Subject: Re: [PATCH] KEYS: asym_tpm: Switch to get_random_bytes() Message-ID: <20191031210330.GA10507@linux.intel.com> References: <20191014190033.GA15552@linux.intel.com> <1571081397.3728.9.camel@HansenPartnership.com> <20191016110031.GE10184@linux.intel.com> <1571229252.3477.7.camel@HansenPartnership.com> <20191016162543.GB6279@linux.intel.com> <1571253029.17520.5.camel@HansenPartnership.com> <20191017180440.GG6667@linux.intel.com> <20191021113939.GA11649@linux.intel.com> <20191029084258.GA5649@linux.intel.com> <1572361096.4812.3.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1572361096.4812.3.camel@HansenPartnership.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Tue, Oct 29, 2019 at 07:58:16AM -0700, James Bottomley wrote: > On Tue, 2019-10-29 at 10:42 +0200, Jarkko Sakkinen wrote: > > On Mon, Oct 21, 2019 at 02:39:39PM +0300, Jarkko Sakkinen wrote: > > > On Thu, Oct 17, 2019 at 09:04:40PM +0300, Jarkko Sakkinen wrote: > > > > On Wed, Oct 16, 2019 at 03:10:29PM -0400, James Bottomley wrote: > > > > > On Wed, 2019-10-16 at 19:25 +0300, Jarkko Sakkinen wrote: > > > > > > On Wed, Oct 16, 2019 at 08:34:12AM -0400, James Bottomley > > > > > > wrote: > > > > > > > reversible ciphers are generally frowned upon in random > > > > > > > number > > > > > > > generation, that's why the krng uses chacha20. In general > > > > > > > I think > > > > > > > we shouldn't try to code our own mixing and instead should > > > > > > > get the > > > > > > > krng to do it for us using whatever the algorithm du jour > > > > > > > that the > > > > > > > crypto guys have blessed is. That's why I proposed adding > > > > > > > the TPM > > > > > > > output to the krng as entropy input and then taking the > > > > > > > output of > > > > > > > the krng. > > > > > > > > > > > > It is already registered as hwrng. What else? > > > > > > > > > > It only contributes entropy once at start of OS. > > > > > > > > Ok. > > > > > > > > > > Was the issue that it is only used as seed when the rng is > > > > > > init'd > > > > > > first? I haven't at this point gone to the internals of krng. > > > > > > > > > > Basically it was similar to your xor patch except I got the > > > > > kernel rng > > > > > to do the mixing, so it would use the chacha20 cipher at the > > > > > moment > > > > > until they decide that's unsafe and change it to something > > > > > else: > > > > > > > > > > https://lore.kernel.org/linux-crypto/1570227068.17537.4.camel@H > > > > > ansenPartnership.com/ > > > > > > > > > > It uses add_hwgenerator_randomness() to do the mixing. It also > > > > > has an > > > > > unmixed source so that read of the TPM hwrng device works as > > > > > expected. > > > > > > > > Thinking that could this potentially racy? I.e. between the calls > > > > something else could eat the entropy added? > > > > > > Also, what is wrong just taking one value from krng and mixing > > > it with a value from TPM RNG where needed? That would be non-racy > > > too. > > > > I guess we can move forward with this? > > Sure I suppose; can we can figure out how to get the mixing function du > jour exposed? Maybe it is best to reflect the whole issue in the context of the Sumit's 2nd patch set, which adds ARM TEE support in order to move forward. /Jarkko From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Sakkinen Date: Thu, 31 Oct 2019 21:03:30 +0000 Subject: Re: [PATCH] KEYS: asym_tpm: Switch to get_random_bytes() Message-Id: <20191031210330.GA10507@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit List-Id: References: <20191014190033.GA15552@linux.intel.com> <1571081397.3728.9.camel@HansenPartnership.com> <20191016110031.GE10184@linux.intel.com> <1571229252.3477.7.camel@HansenPartnership.com> <20191016162543.GB6279@linux.intel.com> <1571253029.17520.5.camel@HansenPartnership.com> <20191017180440.GG6667@linux.intel.com> <20191021113939.GA11649@linux.intel.com> <20191029084258.GA5649@linux.intel.com> <1572361096.4812.3.camel@HansenPartnership.com> In-Reply-To: <1572361096.4812.3.camel@HansenPartnership.com> To: James Bottomley Cc: "Safford, David (GE Global Research, US)" , Ken Goldman , Mimi Zohar , "linux-integrity@vger.kernel.org" , "stable@vger.kernel.org" , "open list:ASYMMETRIC KEYS" , "open list:CRYPTO API" , open list On Tue, Oct 29, 2019 at 07:58:16AM -0700, James Bottomley wrote: > On Tue, 2019-10-29 at 10:42 +0200, Jarkko Sakkinen wrote: > > On Mon, Oct 21, 2019 at 02:39:39PM +0300, Jarkko Sakkinen wrote: > > > On Thu, Oct 17, 2019 at 09:04:40PM +0300, Jarkko Sakkinen wrote: > > > > On Wed, Oct 16, 2019 at 03:10:29PM -0400, James Bottomley wrote: > > > > > On Wed, 2019-10-16 at 19:25 +0300, Jarkko Sakkinen wrote: > > > > > > On Wed, Oct 16, 2019 at 08:34:12AM -0400, James Bottomley > > > > > > wrote: > > > > > > > reversible ciphers are generally frowned upon in random > > > > > > > number > > > > > > > generation, that's why the krng uses chacha20. In general > > > > > > > I think > > > > > > > we shouldn't try to code our own mixing and instead should > > > > > > > get the > > > > > > > krng to do it for us using whatever the algorithm du jour > > > > > > > that the > > > > > > > crypto guys have blessed is. That's why I proposed adding > > > > > > > the TPM > > > > > > > output to the krng as entropy input and then taking the > > > > > > > output of > > > > > > > the krng. > > > > > > > > > > > > It is already registered as hwrng. What else? > > > > > > > > > > It only contributes entropy once at start of OS. > > > > > > > > Ok. > > > > > > > > > > Was the issue that it is only used as seed when the rng is > > > > > > init'd > > > > > > first? I haven't at this point gone to the internals of krng. > > > > > > > > > > Basically it was similar to your xor patch except I got the > > > > > kernel rng > > > > > to do the mixing, so it would use the chacha20 cipher at the > > > > > moment > > > > > until they decide that's unsafe and change it to something > > > > > else: > > > > > > > > > > https://lore.kernel.org/linux-crypto/1570227068.17537.4.camel@H > > > > > ansenPartnership.com/ > > > > > > > > > > It uses add_hwgenerator_randomness() to do the mixing. It also > > > > > has an > > > > > unmixed source so that read of the TPM hwrng device works as > > > > > expected. > > > > > > > > Thinking that could this potentially racy? I.e. between the calls > > > > something else could eat the entropy added? > > > > > > Also, what is wrong just taking one value from krng and mixing > > > it with a value from TPM RNG where needed? That would be non-racy > > > too. > > > > I guess we can move forward with this? > > Sure I suppose; can we can figure out how to get the mixing function du > jour exposed? Maybe it is best to reflect the whole issue in the context of the Sumit's 2nd patch set, which adds ARM TEE support in order to move forward. /Jarkko