[pve-devel] [PATCH access-control 0/3] improve tfa config locking

[Wolfgang Bumiller]

On Thu, Oct 20, 2022 at 03:14:09PM +0200, Dominik Csapak wrote:
> intended as a replacement for my previous patch: [0]
> 
> while we may not want users to login into a non-quorate cluster,
> preventing it as a side-effect of locking the tfa config is wrong.
> 
> currently there is only one situation where we actually need to lock
> the tfa config, namely when using recovery keys, since they have to be
> removed from it. so this series changes the tfa code in pve so that
> we only lock when the tfa response is a recovery key
> 
> an alternative approach to this would be to implement a 'needs save'
> check in rust and call that with the tfa-response, but we can still do
> that later
> 
> patches 2 and 3 are debatable, but i found it makes the code a bit clearer
> 
> my suggestion for the 'let users not login in non-quorate cluster' would
> be to maybe add a flag to the users that must be explicitely enabled
> for them to login, so that e.g. some admin users can always login, but
> normal users cannot (i got no real feedback on that idea in the
> conversation of the last version of this sadly..)

I think it makes sense. Eg. you may not want to expose ssh access
publicly but need the UI - then at least root could access the shell
over the UI to fix stuff, while for other users we can never be sure
they're actually still valid. Although we could argue @pam users should
be allowed to login as well, since those are machine-local after all?
But as far as I'm concerned, even root at pam-only for non-quorate nodes
would make enough sense.