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 <blockdev>' 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 On the one hand, set_password feels outdated from a QAPI point of view: 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 :|
