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=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 C0DEEC7618F for ; Tue, 16 Jul 2019 18:08:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A48EF2173C for ; Tue, 16 Jul 2019 18:08:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728579AbfGPSIq (ORCPT ); Tue, 16 Jul 2019 14:08:46 -0400 Received: from linux.microsoft.com ([13.77.154.182]:40352 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728190AbfGPSIq (ORCPT ); Tue, 16 Jul 2019 14:08:46 -0400 Received: by linux.microsoft.com (Postfix, from userid 1029) id EE9A620B7185; Tue, 16 Jul 2019 11:08:44 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by linux.microsoft.com (Postfix) with ESMTP id CFA0830114FD; Tue, 16 Jul 2019 11:08:44 -0700 (PDT) Date: Tue, 16 Jul 2019 11:08:44 -0700 (PDT) From: Jaskaran Singh Khurana X-X-Sender: jaskarankhurana@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net To: Milan Broz cc: ebiggers@google.com, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-fsdevel@vger.kernel.org, agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com, jmorris@namei.org, Scott Shell , Nazmus Sakib , mpatocka@redhat.com Subject: Re: [RFC PATCH v6 0/1] Add dm verity root hash pkcs7 sig validation. In-Reply-To: <395efa90-65d8-d832-3e2b-2b8ee3794688@gmail.com> Message-ID: References: <20190701181958.6493-1-jaskarankhurana@linux.microsoft.com> <395efa90-65d8-d832-3e2b-2b8ee3794688@gmail.com> User-Agent: Alpine 2.21 (LRH 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Hello Milan, On Tue, 16 Jul 2019, Milan Broz wrote: > On 12/07/2019 19:33, Jaskaran Singh Khurana wrote: >> >> Hello Milan, >> >>> Changes in v6: >>> >>> Address comments from Milan Broz and Eric Biggers on v5. >>> >>> -Keep the verification code under config DM_VERITY_VERIFY_ROOTHASH_SIG. >>> >>> -Change the command line parameter to requires_signatures(bool) which will >>> force root hash to be signed and trusted if specified. >>> >>> -Fix the signature not being present in verity_status. Merged the >>> https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fmbroz%2Flinux.git%2Fcommit%2F%3Fh%3Ddm-cryptsetup%26id%3Da26c10806f5257e255b6a436713127e762935ad3&data=02%7C01%7CJaskaran.Khurana%40microsoft.com%7C18f92445e46940aeebb008d6fe50c610%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636976020210890638&sdata=aY0V9%2FBz2RHryIvoftGKUGnyPp9Fsc1JY4FZbHfW4hg%3D&reserved=0 >>> made by Milan Broz and tested it. >>> >>> >> >> Could you please provide feedback on this v6 version. > > Hi, > > I am ok with the v6 patch; I think Mike will return to it in 5.4 reviews. > Thanks for the help and also for reviewing this patch. Could you please add Reviewed-by/Tested-by tag to the patch. > But the documentation is very brief. I spent quite a long time to configure the system properly. > I think you should add more description (at least to patch header) how to use this feature in combination with system keyring. > I will add more documentation to the patch header describing the steps required for setup. > Do I understand correctly that these steps need to be done? > > - user configures a certificate and adds it in kernel builtin keyring (I used CONFIG_SYSTEM_TRUSTED_KEYS option). > - the dm-verity device root hash is signed directly by a key of this cert > - the signature is uploaded to the user keyring > - reference to signature in keyring is added as an optional dm-verity table parameter root_hash_sig_key_desc > - optionally, require_signatures dm-verity module is set to enforce signatures. > > For reference, below is the bash script I used (with unpatched veritysetup to generate working DM table), is the expected workflow here? The steps and workflow is correct. I will send the cryptsetup changes for review. > > #!/bin/bash > > NAME=test > DEV=/dev/sdc > DEV_HASH=/dev/sdd > ROOT_HASH=778fccab393842688c9af89cfd0c5cde69377cbe21ed439109ec856f2aa8a423 > SIGN=sign.txt > SIGN_NAME=verity:$NAME > > # get unsigned device-mapper table using unpatched veritysetup > veritysetup open $DEV $NAME $DEV_HASH $ROOT_HASH > TABLE=$(dmsetup table $NAME) > veritysetup close $NAME > > # Generate self-signed CA key, must be in .config as CONFIG_SYSTEM_TRUSTED_KEYS="path/ca.pem" > #openssl req -x509 -newkey rsa:1024 -keyout ca_key.pem -out ca.pem -nodes -days 365 -set_serial 01 -subj /CN=example.com > > # sign root hash directly by CA cert > echo -n $ROOT_HASH | openssl smime -sign -nocerts -noattr -binary -inkey ca_key.pem -signer ca.pem -outform der -out $SIGN > > # load signature to keyring > keyctl padd user $SIGN_NAME @u <$SIGN > > # add device-mapper table, now with sighed root hash optional argument > dmsetup create -r $NAME --table "$TABLE 2 root_hash_sig_key_desc $SIGN_NAME" > dmsetup table $NAME > > # cleanup > dmsetup remove $NAME > keyctl clear @u > > Thanks for testing the changes and all the guidance here. > Milan > Regards, Jaskaran.