The Bad Guys Will Cut Off Your Fingers

Now you need to edit your PAM (Pluggable Authentication Modules) configuration so you can log in to your computer with either your usual password, or with your fingerprint:

# mkdir /etc/pam_thinkfinger
#  tf-tool --add-user carla

ThinkFinger 0.3 (http://thinkfinger.sourceforge.net/)
Copyright (C) 2006, 2007 Timo Hoenig 

Initializing... done.
Please swipe your finger (successful swipes 3/3, failed swipes: 6)... done.
Storing data (/etc/pam_thinkfinger/carla.bir)... done.

Configuring PAM is always a heap o' fun. On Debian, the Buntu family, and most Linuxes, add these lines to /etc/pam.d/common_auth before any other pam_unix lines:

auth    sufficient      pam_thinkfinger.so
auth    required        pam_unix.so  try_first_pass

For Fedora, PCLinuxOS, and the rest of the Red Hat extended family, add them to /etc/pam.d/system-auth. SUSE goes its own way entirely. Add uinput to /etc/modules, or whatever your system needs to load modules at boot, and reboot.

Now what happens? My T61 runs PCLinuxOS, and the graphical login manager has absolutely no clue about fingerprint readers. kdesu doesn't know what to do with it, either. So I can't login to a graphical session with my fingerprint. However, at the console prompt I got this:

PCLinuxOS release 2007 for i586
Kernel 2.6.22.10.tex1 on a Dual-processor i686 /tty4
ripley login: carla
Password or swipe finger:

Hurrah! And it worked. It's still a baby and has lot of growing up to do, so please visit Resources for more help and updates. ThinkFinger needs more PAM modules to make it work with different types of authentication and applications, so if you're looking for a FOSS project to support that would be a good one.

Resources

• How to enable the fingerprint reader with ThinkFinger links to a video tutorial for forging fingerprints
• Install ThinkFinger on Ubuntu
• Bug 116682: Support fingerprint reader login in kdm

Carla Schroder is the author of the Linux Cookbook and the newly-released Linux Networking Cookbook, and is a regular contributor to LinuxPlanet.

This article was first published on LinuxPlanet.com.