From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753655AbdKIQSW (ORCPT ); Thu, 9 Nov 2017 11:18:22 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:56116 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753152AbdKIQST (ORCPT ); Thu, 9 Nov 2017 11:18:19 -0500 Subject: Re: [PATCH v2 00/15] ima: digest list feature From: Mimi Zohar To: Matthew Garrett , Roberto Sassu Cc: linux-integrity , linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, silviu.vlasceanu@huawei.com Date: Thu, 09 Nov 2017 11:17:16 -0500 In-Reply-To: References: <20171107103710.10883-1-roberto.sassu@huawei.com> <899b68a6-fefe-a6db-d624-ea83f597caf1@huawei.com> <210975fe-527c-df2f-5a8a-9aca31e9246a@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: 17110916-0012-0000-0000-0000058B7F37 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17110916-0013-0000-0000-000019062BBA Message-Id: <1510244236.4484.172.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-11-09_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1711090220 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2017-11-09 at 09:47 -0500, Matthew Garrett wrote: > This seems very over-complicated, and it's unclear why the kernel > needs to open the file itself. You *know* that all of userland is > trustworthy at this point even in the absence of signatures. Assuming the initramfs is signed, then yes the rootfs files would be trusted.  rootfs can still access files from real root, which is where policies are normally stored. > It seems > reasonable to provide a interface that allows userland to pass a > digest list to the kernel, in the same way that userland can pass an > IMA policy to the kernel. You can then restrict access to that > interface via an LSM. IMA can and should be configured to require signed policies. Mimi