bug#44808: Default to allowing password authentication on leaves users vulnerable

[Christopher Lemmer Webber <cwebber@dustycloud.org>]

Ludovic Courtès writes:

> Hi!
>
> Maxim Cournoyer <maxim.cournoyer@gmail.com> skribis:
>
>>>> I'm on board with what you're proposing, and I think Guix should
>>>> default to the more secure option, but I'm not sure that an 
>>>> "average user" (whatever that means for Guix's demographic) would
>>>> expect that password authentication is disabled by default.
>>>
>>> That's fair... I think that
>>> "[ ] Password authentication? (insecure)"
>>> would be sufficient as an option.  How do others feel?
>>
>> I'm +1 on disabling password access out of the box; especially since
>> Guix System makes it easy to authorize SSH keys at installation time.
>> We'd have to see if it breaks any of our system tests, but I doubt so.
>
> Agreed.  There are several ways to do that:
>
>   1. Have the installer emit an ‘openssh-configuration’ that explicitly
>      disables password authentication.
>
>   2. Change the default value of the relevant field in
>      <openssh-configuration>.
>
> #2 is more thorough but also more risky: people could find themselves
> locked out of their server after reconfiguration, though this could be
> mitigated by a news entry.
>
> Thoughts?
>
> Ludo’.

We could also do a combination of the above, as a transitional plan:
do #1 for now, but try to advertise that in the future, the default will
be changing... please explicitly set password access to #t if you need
this!  Then in the *following* release, change the default.

This seems like a reasonable transition plan, kind of akin to a
deprecation process?