[Nix-dev] Can't SSH into a root account

[Mateusz Kowalczyk]

Hi,

I while ago I put NixOS on another computer. I set it all up and it's
great except for one problem: I can't SSH into the root account on it.
See below for some attempts: I want to SSH from @lenalee to @yuuki. It
just keeps rejecting my password even know I know it's correct: I
demonstrate that by SSHing into a regular user on that box and then
using ‘su’. This also shows that it's not a problem with SSH access in
general, just to that user. The only thing I'm not showing here is
SSHing into root at yuuki from regular user @lenalee because I  set up
login with a public key for convenience. This also that I can actually
log into the user, just not with the password.

I hoped that this would go away after I stopped messing with the users
at install time but it has now been weeks and multiple reboots &c and
the problem persists.

Below is an annotated session dump. I especially point your attention to
the last part.

##
-- Try logging into the root user, fail.
[root at lenalee:/home/shana]# ssh root at yuuki
Password:
Password:
^C

[root at lenalee:/home/shana]# exit

-- Log into the regular user there.
[shana at lenalee:~]$ ssh shana at yuuki
Password:
Last login: Fri Aug 22 11:10:18 2014 from lenalee

-- …and switch to the root that way…
[shana at yuuki:~]$ su
Password:

-- …which works so the password is correct.
[root at yuuki:/home/shana]# exit

[shana at yuuki:~]$ logout
Connection to yuuki closed.

[shana at lenalee:~]$ su
Password:

-- Keep trying, keep failing. That second way of failure and prompting
-- makes me suspicious.
[root at lenalee:/home/shana]# ssh root at yuuki
Password:
Password:
Password:
root at yuuki's password:
Permission denied, please try again.
root at yuuki's password:
Permission denied, please try again.
root at yuuki's password:

[root at lenalee:/home/shana]# exit
##

It'd be great if someone could offer some advice.

-- 
Mateusz K.