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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 E23B7C11D30 for ; Mon, 24 Feb 2020 14:46:21 +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 AE5FB20714 for ; Mon, 24 Feb 2020 14:46:21 +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="DA7jpGos" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AE5FB20714 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]:37648 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j6F00-0002t6-UV for qemu-devel@archiver.kernel.org; Mon, 24 Feb 2020 09:46:20 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53004) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j6Eyt-0001p7-7q for qemu-devel@nongnu.org; Mon, 24 Feb 2020 09:45:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j6Eyr-0007jX-JZ for qemu-devel@nongnu.org; Mon, 24 Feb 2020 09:45:11 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:20006 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j6Eyr-0007jO-Et for qemu-devel@nongnu.org; Mon, 24 Feb 2020 09:45:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582555508; h=from:from:reply-to: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=zgQbu3iw1NSUlvXZeSthSMyiLqigdkaOtMU4+kjUvU4=; b=DA7jpGosBcwjcH6/tkN+p9oV+vqE868aW9shWsmYbGWDu+Wml8NqgjNg5mvbJ+UjEz9eh9 BlBSxXdeOPGvZV6fkYfVNMLK7bvm5xHxgtGQtQEQ9umziGDeRh3YMUjgp+J5S+n7xGkSAm bPnA0zUXfdFe2awUGV/P8GLZB/YrMQs= 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-256-dk2ETjfpOu2pRp2bmhVLBA-1; Mon, 24 Feb 2020 09:45:06 -0500 X-MC-Unique: dk2ETjfpOu2pRp2bmhVLBA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DD9F31005513; Mon, 24 Feb 2020 14:45:05 +0000 (UTC) Received: from redhat.com (unknown [10.42.16.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A3A195D9CD; Mon, 24 Feb 2020 14:45:04 +0000 (UTC) Date: Mon, 24 Feb 2020 14:45:02 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Subject: Re: QAPI schema for desired state of LUKS keyslots (was: [PATCH 02/13] qcrypto-luks: implement encryption key management) Message-ID: <20200224144502.GS635661@redhat.com> References: <20200114193350.10830-1-mlevitsk@redhat.com> <20200114193350.10830-3-mlevitsk@redhat.com> <87lfp36gzh.fsf_-_@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87lfp36gzh.fsf_-_@dusky.pond.sub.org> User-Agent: Mutt/1.13.3 (2020-01-12) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.61 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , qemu-block@nongnu.org, qemu-devel@nongnu.org, Max Reitz , Maxim Levitsky , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sat, Feb 15, 2020 at 03:51:46PM +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. >=20 > 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. OK > I'm going to include a few design options. I'll mark them "Option:". >=20 > 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. >=20 > We commonly have eight LUKS keyslots. Each keyslot is either active or > inactive. An active keyslot holds a secret. >=20 > Goal: a QAPI type for specifying desired state of LUKS keyslots. >=20 > Proposal: >=20 > { 'enum': 'LUKSKeyslotState', > 'data': [ 'active', 'inactive' ] } >=20 > { 'struct': 'LUKSKeyslotActive', > 'data': { 'secret': 'str', > '*iter-time': 'int } } >=20 > { 'struct': 'LUKSKeyslotInactive', > 'data': { '*old-secret': 'str' } } >=20 > { 'union': 'LUKSKeyslotAmend', > 'base': { '*keyslot': 'int', > 'state': 'LUKSKeyslotState' } > 'discriminator': 'state', > 'data': { 'active': 'LUKSKeyslotActive', > 'inactive': 'LUKSKeyslotInactive' } } >=20 > LUKSKeyslotAmend specifies desired state for a set of keyslots. >=20 > Four cases: >=20 > * @state is "active" >=20 > Desired state is active holding the secret given by @secret. Optional > @iter-time tweaks key stretching. >=20 > The keyslot is chosen either by the user or by the system, as follows: >=20 > - @keyslot absent >=20 > One inactive keyslot chosen by the system. If none exists, error. >=20 > - @keyslot present >=20 > The keyslot given by @keyslot. >=20 > If it's already active holding @secret, no-op. Rationale: the > current state is the desired state. >=20 > If it's already active holding another secret, error. Rationale: > update in place is unsafe. >=20 > Option: delete the "already active holding @secret" case. Feels > inelegant to me. Okay if it makes things substantially simpler. >=20 > * @state is "inactive" >=20 > Desired state is inactive. >=20 > Error if the current state has active keyslots, but the desired state > has none. >=20 > The user choses the keyslot by number and/or by the secret it holds, > as follows: >=20 > - @keyslot absent, @old-secret present >=20 > All active keyslots holding @old-secret. If none exists, error. >=20 > - @keyslot present, @old-secret absent >=20 > The keyslot given by @keyslot. >=20 > If it's already inactive, no-op. Rationale: the current state is > the desired state. >=20 > - both @keyslot and @old-secret present >=20 > The keyslot given by keyslot. >=20 > If it's inactive or holds a secret other than @old-secret, error. >=20 > Option: error regardless of @old-secret, if that makes things > simpler. >=20 > - neither @keyslot not @old-secret present >=20 > All keyslots. Note that this will error out due to "desired state > has no active keyslots" unless the current state has none, either. >=20 > Option: error out unconditionally. >=20 > 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. >=20 > Examples: >=20 > * Add a secret to some free keyslot: >=20 > { "state": "active", "secret": "CIA/GRU/MI6" } >=20 > * Deactivate all keyslots holding a secret: >=20 > { "state": "inactive", "old-secret": "CIA/GRU/MI6" } >=20 > * Add a secret to a specific keyslot: >=20 > { "state": "active", "secret": "CIA/GRU/MI6", "keyslot": 0 } >=20 > * Deactivate a specific keyslot: >=20 > { "state": "inactive", "keyslot": 0 } >=20 > Possibly less dangerous: >=20 > { "state": "inactive", "keyslot": 0, "old-secret": "CIA/GRU/MI6" } >=20 > 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). >=20 > Option: LUKSKeyslotInactive member @old-secret could also be named > @secret. I don't care. >=20 > Option: delete @keyslot. It provides low-level slot access. > Complicates the interface. Fine if we need lov-level slot access. Do > we? >=20 > I apologize for the time it has taken me to write this. >=20 > Comments? This is all fine with me. I have no strong opinion on the handful of options listed above, so fine with any choices out of them. Regards, Daniel --=20 |: https://berrange.com -o- https://www.flickr.com/photos/dberrange= :| |: https://libvirt.org -o- https://fstop138.berrange.com= :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange= :|