So tonight, had to add a local user account on one of my development servers... and here is what happened:
comp ~ # passwd newuser
passwd: Critical error - immediate abort
hmm. I've never seen this before. Of course immediate reflex action is to zip to the Gentoo forums. Found out there apparently is a bug related to cracklib (which was a recent upgrade - Thu Oct 11 18:05:48 2007 >>> sys-libs/cracklib-2.8.10).
Simple fix is to do the following:
emerge -1 cracklib shadow