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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 0265EC4360F for ; Thu, 21 Mar 2019 17:46:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D643D21902 for ; Thu, 21 Mar 2019 17:46:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728852AbfCURqF (ORCPT ); Thu, 21 Mar 2019 13:46:05 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:32911 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728766AbfCURp6 (ORCPT ); Thu, 21 Mar 2019 13:45:58 -0400 Received: from LHREML711-CAH.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id 34F6F9CFE424EED2123A; Thu, 21 Mar 2019 17:45:51 +0000 (GMT) Received: from [10.204.65.148] (10.204.65.148) by smtpsuk.huawei.com (10.201.108.34) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 21 Mar 2019 17:45:43 +0000 Subject: Re: [PATCH] security/keys/trusted: Allow operation without hardware TPM To: Dan Williams , Jarkko Sakkinen CC: James Bottomley , Mimi Zohar , David Howells , , linux-nvdimm , Linux Kernel Mailing List , Silviu Vlasceanu References: <155295271345.1945351.6465460744078693578.stgit@dwillia2-desk3.amr.corp.intel.com> <20190321135451.GD4603@linux.intel.com> <809e827b-fdbe-fbb8-8acf-2878ae9f7777@huawei.com> From: Roberto Sassu Message-ID: Date: Thu, 21 Mar 2019 18:45:47 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.204.65.148] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/21/2019 5:30 PM, Dan Williams wrote: > On Thu, Mar 21, 2019 at 7:27 AM Roberto Sassu wrote: >> >> On 3/21/2019 2:54 PM, Jarkko Sakkinen wrote: >>> On Mon, Mar 18, 2019 at 04:45:13PM -0700, Dan Williams wrote: >>>> Rather than fail initialization of the trusted.ko module, arrange for >>>> the module to load, but rely on trusted_instantiate() to fail >>>> trusted-key operations. >>>> >>>> Fixes: 240730437deb ("KEYS: trusted: explicitly use tpm_chip structure...") >>>> Cc: Roberto Sassu >>>> Cc: Jarkko Sakkinen >>>> Cc: James Bottomley >>>> Cc: Jarkko Sakkinen >>>> Cc: Mimi Zohar >>>> Cc: David Howells >>>> Signed-off-by: Dan Williams >>> >>> It should check for chip in each function that uses TPM now that >>> the code does not rely on default chip. Otherwise, the semantics >>> are kind of inconsistent. >> >> If no other TPM function can be used before a successful key >> instantiate, checking for a chip only in trusted_instantiate() seems >> sufficient. Then, the same chip will be used by all TPM functions until >> module unloading, since we incremented the reference count. >> >> I would suggest to move the tpm_default_chip() and init_digests() calls >> to trusted_instantiate() to restore the old behavior of init_trusted(). >> >> trusted_instantiate() should look like: >> --- >> if (!chip) { >> chip = tpm_default_chip(); >> if (!chip) >> return -ENODEV; >> } >> >> if (!digests) { >> ret = init_digests(); >> if (ret < 0) >> return ret; >> } > > This patch already achieves that because tpm_find_get_ops() will fail > and cause tpm_is_tpm2() to return NULL. In addition, the changes I proposed would allow users to create trusted keys if a TPM is added later. CONFIG_TRUSTED_KEYS=y and CONFIG_TCG_TPM=m is a valid configuration. Jarkko, Dan's patch seems sufficient to fix the issue. He could include the changes I proposed in his patch. What is your opinion? Thanks Roberto -- HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Bo PENG, Jian LI, Yanli SHI