Couldn't log in after upgrading ssh, libpam

[SEBASTIEN LAWRENCE BAILARD <slbailard@wisc.edu>]

After upgrading the following packages, I was unable to login to my machine,
either by X or at a virtual terminal; the system behaved as though I was
using an incorrect password.  My lilo boot is not password protected, so
I was able to log in using "init=/bin/bash rw" boot parameters, and
then update new passwords using chpasswd.  The new passwords worked.

I think the culprit is either libpam0g, or ssh trying to implement
shadow passwords on an already shadow-passworded machine.  I'm not
sure what happened precisely, but am willing to follow suggestions
to diagnose the problem.

-Sebastien Bailard
slbailard@wisc.edu

Upgraded packages.
$ ls -l /var/lib/dpkg/info/ | grep "Jul 2"
-rw-r--r--    1 root     root          672 Jul 22 08:55 atlas2-base.list
-rw-r--r--    1 root     root         1594 Jul 22 08:54 bash.list
-rw-r--r--    1 root     root         2402 Jul 22  2002 gettext-base.md5sums
-rwxr-xr-x    1 root     root          207 Jul 22  2002 gettext-base.postinst
-rwxr-xr-x    1 root     root          133 Jul 22  2002 gettext-base.prerm
-rw-r--r--    1 root     root         3505 Jul 22 08:55 gnupg.list
-rwxr-xr-x    1 root     root          247 Jul 25  2002 libc6-dev.preinst
-rw-r--r--    1 root     root           20 Jul 25  2002 libc6.conffiles
-rwxr-xr-x    1 root     root          547 Jul 25  2002 libc6.postrm
-rw-r--r--    1 root     root          227 Jul 22 08:54 libdb3.list
-rw-r--r--    1 root     root          260 Jul 22 08:55 libgtkxmhtml1.list
-rw-r--r--    1 root     root          559 Jul 22 08:55 libkrb53.list
-rw-r--r--    1 root     root         1457 Jul 22 08:54 libpam-modules.list
-rw-r--r--    1 root     root          403 Jul 22 08:54 libpam-runtime.list
-rw-r--r--    1 root     root          455 Jul 22 08:54 libpam0g.list
-rw-r--r--    1 root     root         4155 Jul 22 08:55 man-db.list
-rw-r--r--    1 root     root        24959 Jul 22 08:55 mozilla-firebird.list
-rw-r--r--    1 root     root         1309 Jul 22 08:55 ssh.list

-- System Information:
Debian Release: testing/unstable
Architecture: i386
Kernel: Linux debian 2.4.18-bf2.4 #1 Son Apr 14 09:53:28 CEST 2002 i686
Locale: LANG=C, LC_CTYPE=C

Versions of packages libpam0g depends on:
ii  libc6                         2.3.1-16   GNU C Library: Shared libraries an
ii  libpam-runtime                0.76-13    Runtime support for the PAM librar