Unable to authenticate after upgrade

[Casper Gielen <casper@dse.nl>]

Hi, 
after my daily apt-get upgrade I'm unable to authenticate myself to the 
system.  I've tried su, sudo and kdesu, and all have the same problem.
After entering the they just hang. It doesn't matter if the password is right 
or wrong. It happens both for root and normal users.
I've tried strace'ing su, but when strace'd it always denies my login. I've 
suspect this is normal behaviour.
I am able to ssh into normal accounts, but not the root account.
sudo aptitude does work, so I might be able to fix myself a setuid root shell.
I need this system for my work, so I don't dare logging out or rebooting.
I need help solving this. Does anybody know what is happening, or what to look 
for next?

fyi: I'm using sid, with some packages (including X) from experimental.
-- 
Casper Gielen
casper@zvdk.nl
--
 The irony is that Bill Gates claims to be making a stable operating
     system and Linus Torvalds claims to be trying to take over the
         world.       -- seen on the net