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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 7BF23C11F6A for ; Fri, 2 Jul 2021 12:34:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 67FE9613C7 for ; Fri, 2 Jul 2021 12:34:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232589AbhGBMgg (ORCPT ); Fri, 2 Jul 2021 08:36:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232569AbhGBMge (ORCPT ); Fri, 2 Jul 2021 08:36:34 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5648EC061762 for ; Fri, 2 Jul 2021 05:34:02 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=[127.0.0.1]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1lzIMq-0003K9-Jc; Fri, 02 Jul 2021 14:34:00 +0200 Subject: Re: [PATCH v2 6/6] KEYS: trusted: Introduce support for NXP CAAM-based trusted keys To: Richard Weinberger Cc: Jonathan Corbet , David Howells , Jarkko Sakkinen , James Bottomley , Mimi Zohar , kernel , James Morris , "Serge E. Hallyn" , horia geanta , aymen sghaier , Herbert Xu , davem , Udit Agarwal , Eric Biggers , Jan Luebbe , david , Franck Lenormand , Sumit Garg , "open list, ASYMMETRIC KEYS" , Linux Crypto Mailing List , Linux Doc Mailing List , linux-integrity , linux-kernel , LSM References: <39e6d65ca5d2a0a35fb71d6c1f85add8ee489a19.1624364386.git-series.a.fatoum@pengutronix.de> <1850833581.13438.1625172175436.JavaMail.zimbra@nod.at> <2f608e5a-5a12-6db1-b9bd-a2cd9e3e3671@pengutronix.de> <783613027.15909.1625223222889.JavaMail.zimbra@nod.at> From: Ahmad Fatoum Message-ID: Date: Fri, 2 Jul 2021 14:33:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <783613027.15909.1625223222889.JavaMail.zimbra@nod.at> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: a.fatoum@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02.07.21 12:53, Richard Weinberger wrote: > Ahmad, > > ----- Ursprüngliche Mail ----- >> Von: "Ahmad Fatoum" >>> I'm still think that hard coding the key modifier is not wise. >>> As I said[0], there are folks out there that want to provide their own modifier, >>> so it is not only about being binary compatible with other CAAM blob patches in >>> the wild. >> >> I don't think the characterization as a salt is accurate. AFAIU it's more >> of a namespace, so blobs being loaded are "type-checked" against the modifier. > > Well, the CAAM programmer's reference manual states that the blob key is a 128 bit modifier > and has two purposes: > 1. It can be used as tag to provide separation between blobs to detect accidental replacement of blobs. > 2. But it can also be treated as secret to provide additional protection. Because the blob encryption > key derivation includes the key modifier. > > While you have case 1 in mind, I care about case 2. :-) Ah, using the key modifier as a passphrase didn't occur to me. >>> I'll happily implement that feature after your patches got merged but IMHO we >>> should first agree on an interface. >>> How about allowing another optional parameter to Opt_new and Opt_load >> >> Sound good to me. pcrlock for TPM trusted keys has the same interface. >> >> I'd prefer the new option to accept strings, not hex though. > > Both is possible. If the string starts with "0x" it needs to be decoded to a > 128 bit key. Otherwise it has to be a up to 16 byte string. Fine by me. Looking forward to your patches. :-) Cheers, Ahmad > > Thanks, > //richard > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |