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=-7.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 29E68C76191 for ; Wed, 24 Jul 2019 15:35:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 086B521951 for ; Wed, 24 Jul 2019 15:35:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727771AbfGXPe7 (ORCPT ); Wed, 24 Jul 2019 11:34:59 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:33098 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726846AbfGXPe7 (ORCPT ); Wed, 24 Jul 2019 11:34:59 -0400 Received: from LHREML711-CAH.china.huawei.com (unknown [172.18.7.108]) by Forcepoint Email with ESMTP id A977B46866255EF82649; Wed, 24 Jul 2019 16:34:56 +0100 (IST) Received: from [10.220.96.108] (10.220.96.108) by smtpsuk.huawei.com (10.201.108.34) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 24 Jul 2019 16:34:48 +0100 Subject: Re: [PATCH v4 0/3] initramfs: add support for xattrs in the initial ram disk From: Roberto Sassu To: Rob Landley , , Arvind Sankar CC: Mimi Zohar , , , , , , , , , , , , , , , 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> <1561991485.4067.14.camel@linux.ibm.com> Message-ID: <0c17bf9e-9b0b-b067-cf18-24516315b682@huawei.com> Date: Wed, 24 Jul 2019 17:34:53 +0200 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: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.220.96.108] X-CFilter-Loop: Reflected Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Is there anything I didn't address in this patch set, that is delaying the review? I would appreciate if you can give me a feedback, positive or negative. Thanks a lot! Roberto On 7/15/2019 6:54 PM, Roberto Sassu wrote: > Rob, Peter, Arvind, did you have the chance to have a look at this > version of the patch set? > > Thanks > > Roberto > > > On 7/1/2019 4:31 PM, Mimi Zohar wrote: >> 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 >> > -- HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Li Jian, Shi Yanli