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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7E7A1C2BA83 for ; Sun, 16 Feb 2020 08:06:16 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2E8F92072C for ; Sun, 16 Feb 2020 08:06:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BblzAitW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E8F92072C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58612 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j3EwR-0000iA-55 for qemu-devel@archiver.kernel.org; Sun, 16 Feb 2020 03:06:15 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34632) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j3Eve-0008AU-4F for qemu-devel@nongnu.org; Sun, 16 Feb 2020 03:05:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j3Evc-0001gh-Op for qemu-devel@nongnu.org; Sun, 16 Feb 2020 03:05:26 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:47898 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j3Evc-0001fm-LI for qemu-devel@nongnu.org; Sun, 16 Feb 2020 03:05:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581840324; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=vG/DvFP3L816TZHSKwGjqv+cEYXguCt10l5LNBW7D7I=; b=BblzAitWU9nZ5LNe34yEp5gvmoaCSx29AWv129Dr9SDwqbKyE7jnFWE08bIwu474YumSPa SDC7nYr/l4ZX4RilGR4uS4xQu6vHcXTRQ+FkoQBLQdzpwW07T28vd13UtwKiEAQ+zvw0JF MRFMYG5u5in5tGyXPDSU/xJn9rDA60E= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-236-IxUOUJbkMSSUdICVUYEGjA-1; Sun, 16 Feb 2020 03:05:19 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id AE1EC107ACC7; Sun, 16 Feb 2020 08:05:18 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id A19451000325; Sun, 16 Feb 2020 08:05:16 +0000 (UTC) Message-ID: <59039903dba3c277ef9dbc2397a896c906f120d1.camel@redhat.com> Subject: Re: QAPI schema for desired state of LUKS keyslots (was: [PATCH 02/13] qcrypto-luks: implement encryption key management) From: Maxim Levitsky To: Markus Armbruster Date: Sun, 16 Feb 2020 10:05:15 +0200 In-Reply-To: <87lfp36gzh.fsf_-_@dusky.pond.sub.org> References: <20200114193350.10830-1-mlevitsk@redhat.com> <20200114193350.10830-3-mlevitsk@redhat.com> <87lfp36gzh.fsf_-_@dusky.pond.sub.org> Mime-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: IxUOUJbkMSSUdICVUYEGjA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Daniel =?ISO-8859-1?Q?P=2EBerrang=E9?= , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sat, 2020-02-15 at 15:51 +0100, Markus Armbruster wrote: > Review of this patch led to a lengthy QAPI schema design discussion. > Let me try to condense it into a concrete proposal. > > This is about the QAPI schema, and therefore about QMP. The > human-friendly interface is out of scope. Not because it's not > important (it clearly is!), only because we need to *focus* to have a > chance at success. 100% agree. > > I'm going to include a few design options. I'll mark them "Option:". > > The proposed "amend" interface takes a specification of desired state, > and figures out how to get from here to there by itself. LUKS keyslots > are one part of desired state. > > We commonly have eight LUKS keyslots. Each keyslot is either active or > inactive. An active keyslot holds a secret. > > Goal: a QAPI type for specifying desired state of LUKS keyslots. > > Proposal: > > { 'enum': 'LUKSKeyslotState', > 'data': [ 'active', 'inactive' ] } > > { 'struct': 'LUKSKeyslotActive', > 'data': { 'secret': 'str', > '*iter-time': 'int } } > > { 'struct': 'LUKSKeyslotInactive', > 'data': { '*old-secret': 'str' } } > > { 'union': 'LUKSKeyslotAmend', > 'base': { '*keyslot': 'int', > 'state': 'LUKSKeyslotState' } > 'discriminator': 'state', > 'data': { 'active': 'LUKSKeyslotActive', > 'inactive': 'LUKSKeyslotInactive' } } > > LUKSKeyslotAmend specifies desired state for a set of keyslots. > > Four cases: > > * @state is "active" > > Desired state is active holding the secret given by @secret. Optional > @iter-time tweaks key stretching. > > The keyslot is chosen either by the user or by the system, as follows: > > - @keyslot absent > > One inactive keyslot chosen by the system. If none exists, error. > > - @keyslot present > > The keyslot given by @keyslot. > > If it's already active holding @secret, no-op. Rationale: the > current state is the desired state. > > If it's already active holding another secret, error. Rationale: > update in place is unsafe. > > Option: delete the "already active holding @secret" case. Feels > inelegant to me. Okay if it makes things substantially simpler. I didn't really understand this, since in state=active we shouldn't delete anything. Looks OK otherwise. > > * @state is "inactive" > > Desired state is inactive. > > Error if the current state has active keyslots, but the desired state > has none. > > The user choses the keyslot by number and/or by the secret it holds, > as follows: > > - @keyslot absent, @old-secret present > > All active keyslots holding @old-secret. If none exists, error. > > - @keyslot present, @old-secret absent > > The keyslot given by @keyslot. > > If it's already inactive, no-op. Rationale: the current state is > the desired state. > > - both @keyslot and @old-secret present > > The keyslot given by keyslot. > > If it's inactive or holds a secret other than @old-secret, error. Yea, that would be very nice to have. > > Option: error regardless of @old-secret, if that makes things > simpler. > > - neither @keyslot not @old-secret present > > All keyslots. Note that this will error out due to "desired state > has no active keyslots" unless the current state has none, either. > > Option: error out unconditionally. Yep, that the best IMHO. > > Note that LUKSKeyslotAmend can specify only one desired state for > commonly just one keyslot. Rationale: this satisfies practical needs. > An array of LUKSKeyslotAmend could specify desired state for all > keyslots. However, multiple array elements could then apply to the same > slot. We'd have to specify how to resolve such conflicts, and we'd have > to code up conflict detection. Not worth it. 110% agree (that is not a typo :-) ) > > Examples: > > * Add a secret to some free keyslot: > > { "state": "active", "secret": "CIA/GRU/MI6" } > > * Deactivate all keyslots holding a secret: > > { "state": "inactive", "old-secret": "CIA/GRU/MI6" } > > * Add a secret to a specific keyslot: > > { "state": "active", "secret": "CIA/GRU/MI6", "keyslot": 0 } > > * Deactivate a specific keyslot: > > { "state": "inactive", "keyslot": 0 } > > Possibly less dangerous: > > { "state": "inactive", "keyslot": 0, "old-secret": "CIA/GRU/MI6" } > > Option: Make use of Max's patches to support optional union tag with > default value to let us default @state to "active". I doubt this makes > much of a difference in QMP. A human-friendly interface should probably > be higher level anyway (Daniel pointed to cryptsetup). Also agree. > > Option: LUKSKeyslotInactive member @old-secret could also be named > @secret. I don't care. I prefer old-secret. > > Option: delete @keyslot. It provides low-level slot access. > Complicates the interface. Fine if we need lov-level slot access. Do > we? I don't have strong opinion on that. I'll probably would like to keep this for tests/debugging/etc. > > I apologize for the time it has taken me to write this. Thank you very much for doing this. > > Comments? Looks good to me. Best regards, Maxim Levitsky