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=-15.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,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 EA0E3C07E99 for ; Fri, 9 Jul 2021 14:01:36 +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 4B87961356 for ; Fri, 9 Jul 2021 14:01:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B87961356 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]:47012 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m1r4R-0000ks-03 for qemu-devel@archiver.kernel.org; Fri, 09 Jul 2021 10:01:35 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42580) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1r2l-0008TT-3e for qemu-devel@nongnu.org; Fri, 09 Jul 2021 09:59:51 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:22007) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1r2j-0007ZW-3C for qemu-devel@nongnu.org; Fri, 09 Jul 2021 09:59:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625839186; 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=4HYHPrESxTo4afaYnuyMu296wUezHnkc62bP38HlqbY=; b=h0qJeDY0wfc4w57bFlXM25h+Yf2lRHN4IuO8k7t6TF+9g4Xb1rqwHtBB47zWj61F+m/MPe FN4tvQbcbg+0FgfTHiUH3pssh49INMqi4Znb/hztCCS6V2qQbGC7eQPqwzSacTOhcYr3xU iI3jH1SJi2f/l595nFqpJOeUv7qzpMY= 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-240--cztOgFCNzSU1SemWiOlQg-1; Fri, 09 Jul 2021 09:59:45 -0400 X-MC-Unique: -cztOgFCNzSU1SemWiOlQg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1B511801B0A for ; Fri, 9 Jul 2021 13:59:44 +0000 (UTC) Received: from redhat.com (ovpn-114-175.ams2.redhat.com [10.36.114.175]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 045C55D6A8; Fri, 9 Jul 2021 13:59:32 +0000 (UTC) Date: Fri, 9 Jul 2021 14:59:02 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Subject: Re: [PATCH 11/18] crypto: rename des-rfb cipher to just des Message-ID: References: <20210706095924.764117-1-berrange@redhat.com> <20210706095924.764117-12-berrange@redhat.com> <87eecaffzg.fsf@dusky.pond.sub.org> <87fswo50mf.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87fswo50mf.fsf@dusky.pond.sub.org> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.45, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: Eric Blake , qemu-devel@nongnu.org, Gerd Hoffmann Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Jul 08, 2021 at 04:41:28PM +0200, Markus Armbruster wrote: > Daniel P. Berrangé writes: > > > On Wed, Jul 07, 2021 at 02:47:15PM +0200, Markus Armbruster wrote: > >> Daniel P. Berrangé writes: > >> > >> > Currently the crypto layer exposes support for a 'des-rfb' > >> > algorithm which is just normal single-DES, with the bits > >> > in each key byte reversed. This special key munging is > >> > required by the RFB protocol password authentication > >> > mechanism. > >> > > >> > Since the crypto layer is generic shared code, it makes > >> > more sense to do the key byte munging in the VNC server > >> > code, and expose normal single-DES support. > >> > > >> > Signed-off-by: Daniel P. Berrangé > >> > --- > >> > >> [...] > >> > >> > diff --git a/qapi/crypto.json b/qapi/crypto.json > >> > index 7116ae9a46..6b3fadabac 100644 > >> > --- a/qapi/crypto.json > >> > +++ b/qapi/crypto.json > >> > @@ -66,7 +66,7 @@ > >> > # @aes-128: AES with 128 bit / 16 byte keys > >> > # @aes-192: AES with 192 bit / 24 byte keys > >> > # @aes-256: AES with 256 bit / 32 byte keys > >> > -# @des-rfb: RFB specific variant of single DES. Do not use except in VNC. > >> > +# @des: DES with 56 bit / 8 byte keys. Do not use except in VNC. > >> > # @3des: 3DES(EDE) with 192 bit / 24 byte keys (since 2.9) > >> > # @cast5-128: Cast5 with 128 bit / 16 byte keys > >> > # @serpent-128: Serpent with 128 bit / 16 byte keys > >> > @@ -80,7 +80,7 @@ > >> > { 'enum': 'QCryptoCipherAlgorithm', > >> > 'prefix': 'QCRYPTO_CIPHER_ALG', > >> > 'data': ['aes-128', 'aes-192', 'aes-256', > >> > - 'des-rfb', '3des', > >> > + 'des', '3des', > >> > 'cast5-128', > >> > 'serpent-128', 'serpent-192', 'serpent-256', > >> > 'twofish-128', 'twofish-192', 'twofish-256']} > >> > >> Is enum value "des-rfb" part of any external interface? > > > > Strictly speaking, yes, but in reality it doesn't matter. > > > > > > The only place in QEMU that actually uses DES-RFB is the > > VNC server code. That is an indirect usage when the user > > sets the "password" option flag in QemuOpts. The fact that > > it uses DES-RFB is an internal impl detail. > > > > The one place that does publically expose ability to set a > > field using the QCryptoCipherAlgorithm enum type is the > > LUKS support in the block layer: > > > > { 'struct': 'QCryptoBlockCreateOptionsLUKS', > > 'base': 'QCryptoBlockOptionsLUKS', > > 'data': { '*cipher-alg': 'QCryptoCipherAlgorithm', > > '*cipher-mode': 'QCryptoCipherMode', > > '*ivgen-alg': 'QCryptoIVGenAlgorithm', > > '*ivgen-hash-alg': 'QCryptoHashAlgorithm', > > '*hash-alg': 'QCryptoHashAlgorithm', > > '*iter-time': 'int'}} > > > > eg exposed on CLI as: > > > > $ qemu-img create -f luks -o cipher-alg=NNN foo.luks 1G > > > > or equivalant with QMP blockdev-create > > > > While the QMP schema allows any valid QCryptoCipherAlgorithm > > string to be set, the actual implementation does not. > > > > The crypto/block-luks.c code has a map between cipher algs > > and LUKS format algoritm names: > > > > > > static const QCryptoBlockLUKSCipherNameMap > > qcrypto_block_luks_cipher_name_map[] = { > > { "aes", qcrypto_block_luks_cipher_size_map_aes }, > > { "cast5", qcrypto_block_luks_cipher_size_map_cast5 }, > > { "serpent", qcrypto_block_luks_cipher_size_map_serpent }, > > { "twofish", qcrypto_block_luks_cipher_size_map_twofish }, > > }; > > > > If it isn't in that table, it can't be used. IOW, the only > > scenario we're affecting in this rename is one which would > > already result in an error condition > > > > Original behaviour: > > > > $ qemu-img create -f luks --object secret,id=sec0,data=123 -o cipher-alg=des-rfb,key-secret=sec0 demo.luks 1G > > Formatting 'demo.luks', fmt=luks size=1073741824 key-secret=sec0 cipher-alg=des-rfb > > qemu-img: demo.luks: Algorithm 'des-rfb' not supported > > > > New behaviour: > > > > $ qemu-img create -f luks --object secret,id=sec0,data=123 -o cipher-alg=des-rfb,key-secret=sec0 demo.luks 1G > > Formatting 'demo.luks', fmt=luks size=1073741824 key-secret=sec0 cipher-alg=des-fish > > qemu-img: demo.luks: Invalid parameter 'des-rfb' > > > > I considered this incompatibility to be acceptable, and thus > > not worth going through a deprecation dance. > > Thanks for the explanation. I agree the deprecation dance is not > necessary here. > > Please consider explaining this in your commit message. Suggest to > append a variation of the tail of your explanation: > > Replacing cipher 'des-rfb' by 'des' looks like an incompatible > interface change, but it doesn't matter. While the QMP schema allows > ... > qemu-img: demo.luks: Invalid parameter 'des-rfb' > > Also consider tweaking the title to > > crypto: Replace 'des-rfb' cipher by 'des' > > because it's not actually just a rename. > > Reviewed-by: Markus Armbruster Thanks, I've updated the commit msg as suggested 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 :|