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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 4F01CC06511 for ; Mon, 1 Jul 2019 14:31:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2826F208CA for ; Mon, 1 Jul 2019 14:31:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728145AbfGAObu (ORCPT ); Mon, 1 Jul 2019 10:31:50 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:18018 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728612AbfGAObu (ORCPT ); Mon, 1 Jul 2019 10:31:50 -0400 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x61ESVa9001123 for ; Mon, 1 Jul 2019 10:31:49 -0400 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2tfkvb8muq-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 01 Jul 2019 10:31:48 -0400 Received: from localhost by e06smtp07.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) Mon, 1 Jul 2019 15:31:39 +0100 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x61EVcOE23855312 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 1 Jul 2019 14:31:38 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8C52E4C044; Mon, 1 Jul 2019 14:31:38 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 81A394C058; Mon, 1 Jul 2019 14:31:36 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.81.204]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 1 Jul 2019 14:31:36 +0000 (GMT) Subject: Re: [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk From: Mimi Zohar To: Roberto Sassu , Rob Landley , viro@zeniv.linux.org.uk Cc: linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, initramfs@vger.kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, bug-cpio@gnu.org, zohar@linux.vnet.ibm.com, silviu.vlasceanu@huawei.com, dmitry.kasatkin@huawei.com, takondra@cisco.com, kamensky@cisco.com, hpa@zytor.com, arnd@arndb.de, james.w.mcmechan@gmail.com, niveditas98@gmail.com Date: Mon, 01 Jul 2019 10:31:25 -0400 In-Reply-To: <45164486-782f-a442-e442-6f56f9299c66@huawei.com> References: <20190523121803.21638-1-roberto.sassu@huawei.com> <541e9ea1-024f-5c22-0b58-f8692e6c1eb1@landley.net> <33cfb804-6a17-39f0-92b7-01d54e9c452d@huawei.com> <1561909199.3985.33.camel@linux.ibm.com> <45164486-782f-a442-e442-6f56f9299c66@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: 7bit X-TM-AS-GCONF: 00 x-cbid: 19070114-0028-0000-0000-0000037F5E7C X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19070114-0029-0000-0000-0000243F94B0 Message-Id: <1561991485.4067.14.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-07-01_09:,, 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 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1907010179 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Mon, 2019-07-01 at 16:42 +0300, Roberto Sassu wrote: > On 6/30/2019 6:39 PM, Mimi Zohar wrote: > > On Wed, 2019-06-26 at 10:15 +0200, Roberto Sassu wrote: > >> On 6/3/2019 8:32 PM, Rob Landley wrote: > >>> On 6/3/19 4:31 AM, Roberto Sassu wrote: > >>>>> This patch set aims at solving the following use case: appraise files from > >>>>> the initial ram disk. To do that, IMA checks the signature/hash from the > >>>>> security.ima xattr. Unfortunately, this use case cannot be implemented > >>>>> currently, as the CPIO format does not support xattrs. > >>>>> > >>>>> This proposal consists in including file metadata as additional files named > >>>>> METADATA!!!, for each file added to the ram disk. The CPIO parser in the > >>>>> kernel recognizes these special files from the file name, and calls the > >>>>> appropriate parser to add metadata to the previously extracted file. It has > >>>>> been proposed to use bit 17:16 of the file mode as a way to recognize files > >>>>> with metadata, but both the kernel and the cpio tool declare the file mode > >>>>> as unsigned short. > >>>> > >>>> Any opinion on this patch set? > >>>> > >>>> Thanks > >>>> > >>>> Roberto > >>> > >>> Sorry, I've had the window open since you posted it but haven't gotten around to > >>> it. I'll try to build it later today. > >>> > >>> It does look interesting, and I have no objections to the basic approach. I > >>> should be able to add support to toybox cpio over a weekend once I've got the > >>> kernel doing it to test against. > >> > >> Ok. > >> > >> Let me give some instructions so that people can test this patch set. > >> > >> To add xattrs to the ram disk embedded in the kernel it is sufficient > >> to set CONFIG_INITRAMFS_FILE_METADATA="xattr" and > >> CONFIG_INITRAMFS_SOURCE="" in the kernel configuration. > >> > >> To add xattrs to the external ram disk, it is necessary to patch cpio: > >> > >> https://github.com/euleros/cpio/commit/531cabc88e9ecdc3231fad6e4856869baa9a91ef > >> (xattr-v1 branch) > >> > >> and dracut: > >> > >> https://github.com/euleros/dracut/commit/a2dee56ea80495c2c1871bc73186f7b00dc8bf3b > >> (digest-lists branch) > >> > >> The same modification can be done for mkinitramfs (add '-e xattr' to the > >> cpio command line). > >> > >> To simplify the test, it would be sufficient to replace only the cpio > >> binary and the dracut script with the modified versions. For dracut, the > >> patch should be applied to the local dracut (after it has been renamed > >> to dracut.sh). > >> > >> Then, run: > >> > >> dracut -e xattr -I (add -f to overwrite the ram disk) > >> > >> Xattrs can be seen by stopping the boot process for example by adding > >> rd.break to the kernel command line. > > > > A simple way of testing, without needing any changes other than the > > kernel patches, is to save the dracut temporary directory by supplying > > "--keep" on the dracut command line, calling > > usr/gen_initramfs_list.sh, followed by usr/gen_init_cpio with the "-e > > xattr" option. > > Alternatively, follow the instructions to create the embedded ram disk > with xattrs, and use the existing external ram disk created with dracut > to check if xattrs are created. True, but this alternative is for those who normally use dracut to create an initramfs, but don't want to update cpio or dracut. Mimi