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 9402CC2BA83 for ; Sat, 15 Feb 2020 14:52:36 +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 5775020656 for ; Sat, 15 Feb 2020 14:52:36 +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="Eqq1sdQ9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5775020656 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]:51830 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j2yo7-00039o-Ja for qemu-devel@archiver.kernel.org; Sat, 15 Feb 2020 09:52:35 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:38789) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j2ynW-0002ej-D3 for qemu-devel@nongnu.org; Sat, 15 Feb 2020 09:51:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j2ynQ-0000t8-IY for qemu-devel@nongnu.org; Sat, 15 Feb 2020 09:51:57 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:35614 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 1j2ynQ-0000r0-Dq for qemu-devel@nongnu.org; Sat, 15 Feb 2020 09:51:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581778311; 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=UKIbhaG9tpcPeye9+9rxYj/2sP1grlAm8NUchNLFZgc=; b=Eqq1sdQ9mykhYTvT494l+SS8xMy+ZpnMkVlA3GDDPMyDcnryDtpSfisOIcVhoJ7YePX/GF 9YVTUI9nvjmVu9+02g9BlbQR8ActazTJxiPmA+ZtwJh6dz4Ka/f/6xAfAC3HjFKR4bVPOw cfI4VrmKAeaIheuMRtFQG26KWxAQjus= 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-52-rL7gq_gWMlyhB4COLqvbaQ-1; Sat, 15 Feb 2020 09:51:49 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 69AC48010C4; Sat, 15 Feb 2020 14:51:48 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-117-234.ams2.redhat.com [10.36.117.234]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EA5915C21A; Sat, 15 Feb 2020 14:51:47 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 5A8C611385C9; Sat, 15 Feb 2020 15:51:46 +0100 (CET) From: Markus Armbruster To: Maxim Levitsky Subject: QAPI schema for desired state of LUKS keyslots (was: [PATCH 02/13] qcrypto-luks: implement encryption key management) References: <20200114193350.10830-1-mlevitsk@redhat.com> <20200114193350.10830-3-mlevitsk@redhat.com> Date: Sat, 15 Feb 2020 15:51:46 +0100 In-Reply-To: <20200114193350.10830-3-mlevitsk@redhat.com> (Maxim Levitsky's message of "Tue, 14 Jan 2020 21:33:39 +0200") Message-ID: <87lfp36gzh.fsf_-_@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: rL7gq_gWMlyhB4COLqvbaQ-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Content-Transfer-Encoding: quoted-printable 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 P. =?utf-8?Q?Berrang=C3=A9?=" , 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" 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. 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. * @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. 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. 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. 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). Option: LUKSKeyslotInactive member @old-secret could also be named @secret. I don't care. Option: delete @keyslot. It provides low-level slot access. Complicates the interface. Fine if we need lov-level slot access. Do we? I apologize for the time it has taken me to write this. Comments?