Daniel P. Berrangé <berra...@redhat.com> 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: >> >> * 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.
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). >> >> 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. 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. >> >> 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 figure you mean ``-spice password=string`` (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=... There's also -iscsi password=..., 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.