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 6AB9BC433FE for ; Wed, 30 Nov 2022 09:03:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1p0Izq-0000O1-FX; Wed, 30 Nov 2022 04:03:14 -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 1p0Izo-0000Ne-82 for qemu-devel@nongnu.org; Wed, 30 Nov 2022 04:03:12 -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 1p0Izm-0004x1-7p for qemu-devel@nongnu.org; Wed, 30 Nov 2022 04:03:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1669798988; 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:in-reply-to:in-reply-to: references:references; bh=PDwu57uDJVq0PmawDgnKtY02b7dVQGbJttR74xx8GQ4=; b=RY0EAt7eh4nrp6xghS9Val5SjOprl5wvw9VgrMEl7CAxdZhAChbcvkCibRxY3LNTNLLqZ3 Wst2X875j4GwDXLpfpW2WzA/UwY3Csp/bRQQkhZ5tqvWkbIsgWBpE1e/SxWHY/1FPyVdUf RqcXeHgNMS8MTME+7IxWTePqcFuH+oQ= 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-544-QUq-wSV1NHqrud1-2h6MHQ-1; Wed, 30 Nov 2022 04:03:07 -0500 X-MC-Unique: QUq-wSV1NHqrud1-2h6MHQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0FAE087B2A0 for ; Wed, 30 Nov 2022 09:03:07 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.63]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3CD3F42220; Wed, 30 Nov 2022 09:03:06 +0000 (UTC) Date: Wed, 30 Nov 2022 09:03:03 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, Gerd Hoffmann Subject: Re: Monitor commands related to display server passwords Message-ID: References: <87mt88oonj.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87mt88oonj.fsf@pond.sub.org> User-Agent: Mutt/2.2.7 (2022-08-07) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 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: -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: , 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 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: > > * HMP change vnc > > Change a VNC server password. Unlike set_password below, there's no > way to select a display other than the first. > > 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. 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). > > Password argument since commit 2569da0cb6 "Accept password as an > argument to 'change vnc password' monitor command (Chris Webb)" > (v0.10.0, 2008-12-10). > > Nowadays, this wraps around QMP change-vnc-password, discussed below. > * HMP and QMP set_password, expire_password > > Change a VNC or Spice server password. For Spice, can optionally fail > when connections exist, or disconnect them. > > HMP commands wrap around the respective QMP command, as they should. > > HMP set_password does not support password prompting like "change vnc" > does. > > Commands are present even when both CONFIG_VNC and CONFIG_SPICE are > off. Attempts to use them are rejected manually. Defeats > introspection. > > Since commit 7572150c18 "vnc/spice: add set_passwd monitor command." > (v0.14.0, 2010-12-09) > > 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). > > * QMP change-vnc-password > > Can only target the first VNC display, unlike set_password. > > Command present only with CONFIG_VNC. > > 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. > 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. > > 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. > > 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. > > 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 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. 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 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 :|