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 31776C2D0DB for ; Fri, 31 Jan 2020 14:55:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0F0BE217BA for ; Fri, 31 Jan 2020 14:55:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729145AbgAaOzm (ORCPT ); Fri, 31 Jan 2020 09:55:42 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:47344 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729001AbgAaOzm (ORCPT ); Fri, 31 Jan 2020 09:55:42 -0500 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00VEtf5m047587 for ; Fri, 31 Jan 2020 09:55:41 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2xvkrff08n-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 31 Jan 2020 09:55:41 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 31 Jan 2020 14:50:39 -0000 Received: from b06avi18626390.portsmouth.uk.ibm.com (9.149.26.192) by e06smtp07.uk.ibm.com (192.168.101.137) with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 31 Jan 2020 14:50:36 -0000 Received: from d06av25.portsmouth.uk.ibm.com (d06av25.portsmouth.uk.ibm.com [9.149.105.61]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 00VEnh0Z41615722 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 31 Jan 2020 14:49:43 GMT Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BB3BC11C04A; Fri, 31 Jan 2020 14:50:35 +0000 (GMT) Received: from d06av25.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E76FD11C052; Fri, 31 Jan 2020 14:50:34 +0000 (GMT) Received: from localhost.localdomain (unknown [9.85.193.32]) by d06av25.portsmouth.uk.ibm.com (Postfix) with ESMTP; Fri, 31 Jan 2020 14:50:34 +0000 (GMT) Subject: Re: [PATCH 7/8] ima: use ima_hash_algo for collision detection in the measurement list 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 Date: Fri, 31 Jan 2020 09:50:34 -0500 In-Reply-To: References: <20200127170443.21538-1-roberto.sassu@huawei.com> <20200127170443.21538-8-roberto.sassu@huawei.com> <1580423169.6104.18.camel@linux.ibm.com> <44c1b3f6d3fe414e914317ef8e5c6f8f@huawei.com> <1580480525.6104.88.camel@linux.ibm.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: 7bit X-TM-AS-GCONF: 00 x-cbid: 20013114-0028-0000-0000-000003D64945 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20013114-0029-0000-0000-0000249A9BA2 Message-Id: <1580482234.6104.92.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-01-31_03:2020-01-31,2020-01-31 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 spamscore=0 mlxlogscore=999 priorityscore=1501 phishscore=0 bulkscore=0 malwarescore=0 mlxscore=0 lowpriorityscore=0 clxscore=1015 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1911200001 definitions=main-2001310126 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Fri, 2020-01-31 at 14:41 +0000, Roberto Sassu wrote: > I thought that using a stronger algorithm for hash collision detection but > doing remote attestation with the weaker would not bring additional value. > > If there is a hash collision on SHA1, an attacker can still replace the data of > one of the two entries in the measurement list with the data of the other > without being detected (without additional countermeasures). > > If the verifier additionally checks for duplicate template digests, he could > detect the attack (IMA would not add a new measurement entry with the > same template digest of previous entries). > > Ok, I will use ima_hash_algo for hash collision detection. Thanks! Mimi