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=unavailable 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 7128AC43441 for ; Mon, 19 Nov 2018 15:09:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4017620870 for ; Mon, 19 Nov 2018 15:09:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4017620870 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729744AbeKTBdk (ORCPT ); Mon, 19 Nov 2018 20:33:40 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:32778 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729474AbeKTBdj (ORCPT ); Mon, 19 Nov 2018 20:33:39 -0500 Received: from LHREML713-CAH.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id CA506E165B257; Mon, 19 Nov 2018 15:09:41 +0000 (GMT) Received: from [10.204.65.144] (10.204.65.144) by smtpsuk.huawei.com (10.201.108.36) with Microsoft SMTP Server (TLS) id 14.3.408.0; Mon, 19 Nov 2018 15:09:34 +0000 Subject: Re: [PATCH v5 6/7] tpm: ensure that the output of PCR read contains the correct digest size To: Jarkko Sakkinen CC: , , , , , , , References: <20181114153108.12907-1-roberto.sassu@huawei.com> <20181114153108.12907-7-roberto.sassu@huawei.com> <20181116134153.GD4163@linux.intel.com> <05c7c936-da58-f386-0a43-69e96d6e18a8@huawei.com> <20181118073207.GC5897@linux.intel.com> <20181119143357.GG8755@linux.intel.com> From: Roberto Sassu Message-ID: Date: Mon, 19 Nov 2018 16:09:34 +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: <20181119143357.GG8755@linux.intel.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.204.65.144] X-CFilter-Loop: Reflected Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 11/19/2018 3:33 PM, Jarkko Sakkinen wrote: > On Mon, Nov 19, 2018 at 09:14:00AM +0100, Roberto Sassu wrote: >> On 11/18/2018 8:32 AM, Jarkko Sakkinen wrote: >>> On Fri, Nov 16, 2018 at 05:06:48PM +0100, Roberto Sassu wrote: >>>> On 11/16/2018 2:41 PM, Jarkko Sakkinen wrote: >>>>> On Wed, Nov 14, 2018 at 04:31:07PM +0100, Roberto Sassu wrote: >>>>>> This patch protects against data corruption that could happen in the bus, >>>>>> by checking that that the digest size returned by the TPM during a PCR read >>>>>> matches the size of the algorithm passed to tpm2_pcr_read(). >>>>>> >>>>>> This check is performed after information about the PCR banks has been >>>>>> retrieved. >>>>>> >>>>>> Signed-off-by: Roberto Sassu >>>>>> Reviewed-by: Jarkko Sakkinen >>>>>> Cc: stable@vger.kernel.org >>>>> >>>>> Missing fixes tag. >>>> >>>> Before this patch set, tpm2_pcr_extend() always copied 20 bytes from the >>>> output sent by the TPM. >>>> >>>> Roberto >>> >>> Aah, right, of course. Well the patch set is ATM somewhat broken because >>> this would require a fixes tag that points to a patch insdie the patch >>> set. >>> >>> Probably good way to fix the issue is to just merge this with the >>> earlier commit. >> >> Unfortunately, it is not possible. The exact digest size has been >> introduced with patch 5/7. > > I put this in simple terms: if I merge 5/7 the driver will be broken. > Any commit in the patch set should not leave the tree in broken state. Patch 6/7 does not fix patch 5/7. The check in patch 6/7 is not done for the PCR read performed by patch 5/7, because the digest sizes are not yet available. Roberto > That implies that 5/7 and 6/7 cannot be separate commits. > > /Jarkko > -- HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Bo PENG, Jian LI, Yanli SHI