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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 DE07CC2D0DB for ; Thu, 30 Jan 2020 22:26:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC41E2083E for ; Thu, 30 Jan 2020 22:26:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726327AbgA3W05 (ORCPT ); Thu, 30 Jan 2020 17:26:57 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:36810 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726707AbgA3W05 (ORCPT ); Thu, 30 Jan 2020 17:26:57 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00UM6u4G075862 for ; Thu, 30 Jan 2020 17:26:56 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2xttw8uyev-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 30 Jan 2020 17:26:55 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 30 Jan 2020 22:26:49 -0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 00UMQmCB23461998 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 30 Jan 2020 22:26:48 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 48845AE051; Thu, 30 Jan 2020 22:26:48 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4C162AE056; Thu, 30 Jan 2020 22:26:47 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.209.158]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 30 Jan 2020 22:26:47 +0000 (GMT) Subject: Re: [PATCH 0/8] ima: support stronger algorithms for attestation From: Mimi Zohar To: Roberto Sassu , jarkko.sakkinen@linux.intel.com, james.bottomley@hansenpartnership.com, linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, silviu.vlasceanu@huawei.com Date: Thu, 30 Jan 2020 17:26:46 -0500 In-Reply-To: <20200127170443.21538-1-roberto.sassu@huawei.com> References: <20200127170443.21538-1-roberto.sassu@huawei.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 20013022-4275-0000-0000-0000039C9631 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20013022-4276-0000-0000-000038B0B55D Message-Id: <1580423206.6104.19.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-30_07:2020-01-30,2020-01-30 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 suspectscore=0 lowpriorityscore=0 adultscore=0 malwarescore=0 phishscore=0 priorityscore=1501 spamscore=0 mlxlogscore=999 impostorscore=0 bulkscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1911200001 definitions=main-2001300147 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Hi Roberto, On Mon, 2020-01-27 at 18:04 +0100, Roberto Sassu wrote: > IMA extends Platform Configuration Registers (PCRs) of the TPM to give a > proof to a remote verifier that the measurement list contains all > measurements done by the kernel and that the list was not maliciously > modified by an attacker. > > IMA was originally designed to extend PCRs with a SHA1 digest, provided > with the measurement list, and was subsequently updated to extend all PCR > banks in case a TPM 2.0 is used. Non-SHA1 PCR banks are not supposed to be > used for remote attestation, as they are extended with a SHA1 digest padded > with zeros, which does not increase the strength. > > This patch set addresses this issue by extending PCRs with the digest of > the measurement entry calculated with the crypto subsystem. The list of > algorithms used to calculate the digest are taken from > ima_tpm_chip->allocated_banks, returned by the TPM driver. The SHA1 digest > is always calculated, as SHA1 still remains the default algorithm for the > template digest in the measurement list. > > This patch set also makes two additional modifications related to the usage > of hash algorithms. First, since now the template digest for the default > IMA algorithm is always calculated, this is used for hash collision > detection, to check if there are duplicate measurement entries. > > Second, it uses the default IMA hash algorithm to calculate the boot > aggregate, assuming that the corresponding PCR bank is currently allocated. > Otherwise, it finds the first PCR bank for which the crypto ID is known. > IMA initialization fails only if no algorithm known to the crypto subsystem > is found. > > This patch set does not yet modify the format of the measurement list to > provide the digests passed to the TPM. However, reconstructing the value of > the quoted PCR is still possible for the verifier by calculating the digest > on measurement data found in binary_runtime_measurements. Thank you!  I'm still reviewing and testing the patches, but it is really nicely written. Mimi