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 71089C433FE for ; Wed, 30 Nov 2022 13:26:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p0N6C-0002MS-80; Wed, 30 Nov 2022 08:26:04 -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 1p0N69-0002L7-Sz for qemu-devel@nongnu.org; Wed, 30 Nov 2022 08:26:01 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1p0N67-0005su-VH for qemu-devel@nongnu.org; Wed, 30 Nov 2022 08:26:01 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669814758; 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=gHjxwQ44ggK/z6M9yMiX1XVuhz9KDwnAelceSsDOYpE=; b=NiWdiXEQAQEZP8hjbXRQ2IzDf0E0scmdaJVNb4eXmAdZskGwd6tJKkF84offEHXkM4GnxM E2J8RiqWlp5qvkqCGaEjNObrN1xrK/rdXutMxzeWl09smfZa352aWC+eOV3boUugAem4uo 5KZXXKhbT+y5ISLhhpXuRNE7E9eKC7c= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-610-MOh5BueAPX6WWY6J6w5aMg-1; Wed, 30 Nov 2022 08:25:57 -0500 X-MC-Unique: MOh5BueAPX6WWY6J6w5aMg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id E9548801755 for ; Wed, 30 Nov 2022 13:25:56 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9E75D111F3B0; Wed, 30 Nov 2022 13:25:56 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 9491321E6921; Wed, 30 Nov 2022 14:25:53 +0100 (CET) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: qemu-devel@nongnu.org, Gerd Hoffmann Subject: Re: Monitor commands related to display server passwords References: <87mt88oonj.fsf@pond.sub.org> Date: Wed, 30 Nov 2022 14:25:53 +0100 In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Wed, 30 Nov 2022 09:03:03 +0000") Message-ID: <87h6yglgke.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@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_H2=-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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Daniel P. Berrang=C3=A9 writes: > On Wed, Nov 30, 2022 at 09:02:56AM +0100, Markus Armbruster wrote: >> We have a couple of password-related commands, and I'm not sure about >> which ones should be used. In order of appearance: >>=20 >> * HMP change vnc >>=20 >> Change a VNC server password. Unlike set_password below, there's no >> way to select a display other than the first. >>=20 >> Note: if change's second argument isn't "vnc", w're changing removable >> media. If you call your block device "vnc", you cannot change its >> media. Hilarious. > > Note, QMP equivalent is blockdev-change-medium, which is an wrapper > around a blockdev-open-tray/remove-medium/insert-medium/close-tray > sequence. 'change ' maps to this. Yes. > If you call your blockdev 'vnc' you're not getting sympathy > from me ;-P But seriously, I agree with your point. > >> Password prompting (with hidden user input) since commit 7084851534 >> "VNC password authentication, by Daniel P. Berrange." (v0.9.1, >> 2007-08-25). >>=20 >> Password argument since commit 2569da0cb6 "Accept password as an >> argument to 'change vnc password' monitor command (Chris Webb)" >> (v0.10.0, 2008-12-10). >>=20 >> Nowadays, this wraps around QMP change-vnc-password, discussed below. > >> * HMP and QMP set_password, expire_password >>=20 >> Change a VNC or Spice server password. For Spice, can optionally fail >> when connections exist, or disconnect them. >>=20 >> HMP commands wrap around the respective QMP command, as they should. >>=20 >> HMP set_password does not support password prompting like "change vnc" >> does. >>=20 >> Commands are present even when both CONFIG_VNC and CONFIG_SPICE are >> off. Attempts to use them are rejected manually. Defeats >> introspection. >>=20 >> Since commit 7572150c18 "vnc/spice: add set_passwd monitor command." >> (v0.14.0, 2010-12-09) >>=20 >> Support for VNC displays other than the first since commit 675fd3c96b >> "qapi/monitor: allow VNC display id in set/expire_password" (v7.0.0, >> 2022-03-02). >>=20 >> * QMP change-vnc-password >>=20 >> Can only target the first VNC display, unlike set_password. >>=20 >> Command present only with CONFIG_VNC. >>=20 >> Since commit 270b243f91 "qapi: Introduce change-vnc-password" (v1.1, >> 2012-01-18). > > IIRC, this was designed as a 1-1 mapping to replace the QMP > 'change vnc' command, except it was obviously redundant > since we had already added 'set_passwd' by that point. I > vaguely recall this was all just an oversight on part of > author and reviewers.=20 Happens. >> Do we really need / want both set_password and change-vnc-password in >> QMP? > > Nope. > >> On the one hand, set_password feels outdated from a QAPI point of view: >> it violates the naming rules, and it defeats introspection. On the >> other hand, it's more powerful. >>=20 >> Do we really need / want both set_password and "change vnc" in HMP? >> set_password is more powerful, but only "change vnc" supports password >> prompting. >>=20 >> Getting rid of "change vnc" would fix the "cannot change media for block >> device named 'vnc'" wart. > >> Related: QCryptoSecret objects. > > snip > >> Currently used by various block backends and the tls-creds-x509 object. >>=20 >> Would it make sense with display servers, too? > > In 6.0 I introduced support for 'password-secret' to SPICE and VNC > command line. > > I don't know why, but I only deprecated 'password' in SPICE and > not in VNC. I figure you mean ``-spice password=3Dstring`` (since 6.0) '''''''''''''''''''''''''''''''''''''' This option is insecure because the SPICE password remains visible in the process listing. This is replaced by the new ``password-secret`` option which lets the password be securely provided on the command line using a ``secret`` object instance. and -vnc password=3D... There's also -iscsi password=3D..., and possibly more. > I didn't wire up any QMP commands todo live password changes. If > the display was already configured with 'password-secret', you > could delete and re-create the existing named secret object > using object-add/object-del, since we fetch the secret value > on every auth check. Is this behavior documented? > There's no way to change from password-off to password-on mode > and vica-verca. > > Also no way to change other things like expiry time, > > We since gained the 'display-update' command, which could be > extended to allow change expiry time, and turning on/off > use of passwords, and even changing what 'secret' they > point to. > > So overall I say > > * Deprecate VNC 'password' option > * Deprecated QMP and HMP commands for changing VNC/SPICE > password > * Extend 'display-update' other other misc live changes Makes sense. Of course, we can deprecate the old commands for changing passwords only after we extended display-update to replace them.