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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 010E7C4167B for ; Mon, 4 Dec 2023 16:52:19 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rACAj-0003kp-6V; Mon, 04 Dec 2023 11:51:53 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rACAh-0003k2-0U for qemu-devel@nongnu.org; Mon, 04 Dec 2023 11:51:51 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rACAe-0008G8-1z for qemu-devel@nongnu.org; Mon, 04 Dec 2023 11:51:49 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1701708707; 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=ZjeYhSrLAJWPZuMr6MnJnhqTTD6ek5iI7v8tikI/R3g=; b=PnB8Sj/EvPtBSEJTQ7tkwvUnjTuYxcDRv6VyADSnOLQPZsspaANkAtgpF2HejT/bXIbxC3 oHaXyAg6qpaWVGStku8lqAqkHsfeaVQ9nFQ2+NmjeSmOt3+IV+KK5sD+ZrxgMk6taeaSb6 Y3JdcpEuwtj2orTpy7WbY7d/E3OT+qI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-349-tCGAXfxfONGEU6l6RyKkAA-1; Mon, 04 Dec 2023 11:51:43 -0500 X-MC-Unique: tCGAXfxfONGEU6l6RyKkAA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 773D3185A781; Mon, 4 Dec 2023 16:51:43 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.108]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 17FFC502A; Mon, 4 Dec 2023 16:51:41 +0000 (UTC) Date: Mon, 4 Dec 2023 16:51:39 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Yong Huang Cc: qemu-devel@nongnu.org, Kevin Wolf , Hanna Reitz , Eric Blake , Markus Armbruster Subject: Re: [RFC 0/8] Support generic Luks encryption Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.10 (2023-03-25) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue, Dec 05, 2023 at 12:41:16AM +0800, Yong Huang wrote: > On Tue, Dec 5, 2023 at 12:24 AM Daniel P. Berrangé > wrote: > > > On Tue, Dec 05, 2023 at 12:06:17AM +0800, Hyman Huang wrote: > > > This functionality was motivated by the following to-do list seen > > > in crypto documents: > > > https://wiki.qemu.org/Features/Block/Crypto > > > > > > The last chapter says we should "separate header volume": > > > > > > The LUKS format has ability to store the header in a separate volume > > > from the payload. We should extend the LUKS driver in QEMU to support > > > this use case. > > > > > > As a proof-of-concept, I've created this patchset, which I've named > > > the Gluks: generic luks. As their name suggests, they offer encryption > > > for any format that QEMU theoretically supports. > > > > I don't see the point in creating a new driver. > > > > I would expect detached header support to be implemented via an > > optional new 'header' field in the existing driver. ie > > > > diff --git a/qapi/block-core.json b/qapi/block-core.json > > index ca390c5700..48d1f2a974 100644 > > --- a/qapi/block-core.json > > +++ b/qapi/block-core.json > > @@ -3352,11 +3352,15 @@ > > # decryption key (since 2.6). Mandatory except when doing a > > # metadata-only probe of the image. > > # > > +# @header: optional reference to the location of a blockdev > > +# storing a detached LUKS heaer > > +# > > # Since: 2.9 > > ## > > { 'struct': 'BlockdevOptionsLUKS', > > 'base': 'BlockdevOptionsGenericFormat', > > - 'data': { '*key-secret': 'str' } } > > + 'data': { '*key-secret': 'str', > > + "*header-file': 'BlockdevRef'} } > > > > ## > > # @BlockdevOptionsGenericCOWFormat: > > @@ -4941,9 +4945,18 @@ > > # > > # Driver specific image creation options for LUKS. > > # > > -# @file: Node to create the image format on > > +# @file: Node to create the image format on. Mandatory > > +# unless a detached header file is specified using > > +# @header. > > # > > -# @size: Size of the virtual disk in bytes > > +# @size: Size of the virtual disk in bytes. Mandatory > > +# unless a detached header file is specified using > > +# @header. > > +# > > +# @header: optional reference to the location of a blockdev > > +# storing a detached LUKS heaer. The @file option is > > +# is optional when this is given, unless it is desired > > +# to perform pre-allocation > > # > > # @preallocation: Preallocation mode for the new image (since: 4.2) > > # (default: off; allowed values: off, metadata, falloc, full) > > @@ -4952,8 +4965,9 @@ > > ## > > { 'struct': 'BlockdevCreateOptionsLUKS', > > 'base': 'QCryptoBlockCreateOptionsLUKS', > > - 'data': { 'file': 'BlockdevRef', > > - 'size': 'size', > > + 'data': { '*file': 'BlockdevRef', > > + '*size': 'size', > > + '*header': 'BlockdevRef' > > '*preallocation': 'PreallocMode' } } > > > > ## > > > > It ends up giving basicallly the same workflow as you outline, > > without needing the new block driver > > > > How about the design and usage, could it be simpler? Any advice? :) > > > As you can see below, the Gluks format block layer driver's design is > quite simple. > > virtio-blk/vhost-user-blk...(front-end device) > ^ > | > Gluks (format-like disk node) > / \ > file header (blockdev reference) > / \ > file file (protocol node) > | | > disk data Luks data What I suggested above ends up with the exact same block driver graph, unless I'm missing something. With regards, Daniel -- |: 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 :|