How to enable the integrated fingerprint reader with ThinkFinger

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How to enable the fingerprint reader has a good explanation for using the fingerprint reader with the closed-source binary driver. But there is also an opensource project called ThinkFinger which does the same, but open.

However: The fingerprint reader is an INSECURE device and gives a false sense of security! There has been quite a bit of research by a hacker named Starbug, a member of the Chaos Computer Club, Berlin, Germany. He outlined in two very good talks how to forge each and every available fingerprint sensor available at the cost of a few euros, using materials from your local hardware store, a digicam and a laser printer! Here's some links:


From source

Download thinkfinger-0.3.tar.gz from the homepage and unpack it somewhere, make sure you have the gcc compiler, libtool, pkg-config, libusb-dev and libpam0g-dev installed, then:

$ cd thinkfinger-0.3

$ ./configure --prefix=/usr --sysconfdir=/etc --with-securedir=/lib/security --with-birdir=/etc/pam_thinkfinger

$ make

# make install

/lib/security is the directory, where PAM assumes its modules on Debian and openSUSE, it may vary for your distro!

"make install" doesn't create the birdir we specified (where thinkfinger will store users' biometric info), so create it:

# mkdir /etc/pam_thinkfinger

If everything went OK assert that you find in /lib/security typing:

$ ls /lib/security

From package


Packages arrived in Debian experimental on Aug 2nd, 2007 (cf. bug #409563). To access the experimental packages via apt, add the following lines to your sources.list:

# experimental
deb experimental main contrib non-free
deb-src experimental main contrib non-free

where of course you may replace with your mirror of choice. Just make sure that it hosts the experimental repositories.

aptitude update 
aptitude install libthinkfinger0 libpam-thinkfinger thinkfinger-tools

should then get you up and running.



Hardy includes the latest thinkfinger and it is up to date with subversion. Install packages:

$ sudo apt-get install thinkfinger-tools libpam-thinkfinger

Update the pam configuration files:

$ sudo /usr/lib/pam-thinkfinger/pam-thinkfinger-enable

Enroll your fingerprint (creates $HOME/.thinkfinger.bir). If this gives an error about claiming the USB device then reboot.
Do not try to enroll using 'sudo' - it will cause hidden permission problems

$ tf-tool --acquire

Check fingerprint enrollment

$ tf-tool --verify

You can expect everything to work correctly. Note that you still have to enter your username if prompted but will be able to swipe your finger instead of the password. The prompt will usually be "Password or swipe finger"

  • Graphical login
  • Text console login
  • sudo
  • screen lock/screen saver
  • Administrative password prompt (eg for update or package managers). (Note no "or swipe finger" in prompt).


Add PPA repositories to your sources.list:

deb gutsy main restricted universe multiverse
deb-src gutsy main restricted universe multiverse

Install necessary packages:

$ sudo apt-get install thinkfinger-tools libpam-thinkfinger

Fedora/Fedora Core

  • Packages for Fedora Core 6 are available in "extras" repository (# yum install thinkfinger).
  • Packages for Fedora 7 are available in the "updates" repository (# yum install thinkfinger).


emerge sys-auth/thinkfinger


openSUSE 10.2 includes the package "libthinkfinger" (version 0.1-7) - you will find newer packages here.

Testing the driver

Now the driver is installed and should be working. You can try it (as root) with

# tf-tool --acquire


# tf-tool --verify

This will ask you to swipe your finger three times, save the fingerprint to /tmp/test.bir and then verify your fingerprint with the bir-file.

Configuring PAM to use ThinkFinger

Now you can configure PAM to use ThinkFinger:

Open /etc/pam.d/common-auth (In FC6, F7, and Gentoo, this file is /etc/pam.d/system-auth):

# nano -w /etc/pam.d/common-auth

Add this line before any pam_unix or pam_unix2 directives:

auth     sufficient

If your PAM uses the pam_unix and not the pam_unix2 module, you need to pass a specific argument in the /etc/pam.d/common-auth directive to make it consider the password entered at the pam_thinkfinger prompt.

auth     required try_first_pass

For instance, /etc/pam.d/common-auth looks like this:

auth    sufficient
auth    required nullok_secure try_first_pass

On openSUSE 10.2, it looks like this now:

auth    required
auth    sufficient
auth    required

Now we are ready to add users to thinkfinger. You can add a fingerprint for a user with:

# tf-tool --add-user $USERNAME

Now the user should be able to login with his finger instead of the password.

If you would like to use thinkfinger for su, you have to enroll the fingerprint for root user with:

# tf-tool --add-user root

You should see the "Password or swipe finger:" prompt when trying to sudo or su. If you don't, you probably do not have the "User level driver support" compiled into your kernel or the "uinput" module loaded!


In Fedora 7, the package has been modified in such a way as to make doing this unnecessary.

If you'd like to be able to unlock your screen using the fingerprint reader, you must have current versions of xscreesaver (>~5.03) or gnome-screensaver (>~2.18.2). Then you must give yourself access to the fingerprint reader and your bir-file, because unlike login/gdm/su/sudo, both gnome-screensaver and xscreensaver do not run as root. The following procedure will make the fingerprint reader accessible to members of the "fingerprint" group.

Make the group: # groupadd fingerprint

Save the following as /etc/udev/rules.d/60-thinkfinger.rules (you may need to reboot for this to take effect):

# udev rules file for the thinkfinger fingerprint scanner
# gives access to the fingerprint reader to those in the "fingerprint" group
# Taken from:
# which was taken and modified from:

# SGS Thomson Microelectronics Fingerprint Reader
SYSFS{idVendor}=="0483", SYSFS{idProduct}=="2016", SYMLINK+="input/thinkfinger-%k", MODE="0660", GROUP="fingerprint"

# the also-needed uinput device
KERNEL=="uinput", MODE="0660", GROUP="fingerprint"

Finally, edit /etc/pam.d/gnome-screensaver so that it looks like this:

auth    sufficient
auth    required try_first_pass nullok_secure

Per user:

  1. Add him to the group: # gpasswd -a $USERNAME fingerprint
  2. Make him owner of his bir-file: # chown $USERNAME:root /etc/pam_thinkfinger/$USERNAME.bir
  3. Give him read-only access to his bir-file: # chmod 400 /etc/pam_thinkfinger/$USERNAME.bir
  4. Give "execute only" access to everyone for the /etc/pam_thinkfinger/ directory: # chmod o+x /etc/pam_thinkfinger (WARNING: this opens up security a little).


This problem should be solved if you're using sudo >= 1.6.9p9. Links: [1], [2], [3]

gksu/gksudo doesn't work correctly. It just stays invisible. When starting a su privileged application such as synaptics you will not get prompted for the password. Nevertheless you can swipe your finger and it should authenticate you. Starting synaptics twice makes gksudo visible.

There are two possibilities to solve it:

  • Changing the string "Password or swipe finger:" to a plain "Password:" (like sudo normally would do) in the file pam/pam_thinkfinger.c of the thinkfinger source directory. Of course, in the console you will then only see a "Password:" instead of "Password or swipe finger:" but this is still more usefull than having gksu/gksudo crashing everytime.
  • Patching libgksu with the following patch. This is also a nasty hack until a better solution is implemented.
--- libgksu-2.0.3/libgksu/libgksu.c.orig	2007-06-17 16:00:24.000000000 +0200
+++ libgksu-2.0.3/libgksu/libgksu.c		2007-06-17 16:00:47.000000000 +0200
@@ -2663,7 +2663,7 @@
       for (counter = 0; counter < 50; counter++)
-	  if (strncmp (buffer, "GNOME_SUDO_PASS", 15) == 0)
+	  if (strncmp (buffer, "GNOME_SUDO_PASS", 15) == 0 || strncmp (buffer, "Password or swi", 15) == 0)
 	  read_line (parent_pipe[0], buffer, 256);
@@ -2675,7 +2675,7 @@
       if (context->debug)
 	fprintf (stderr, "brute force GNOME_SUDO_PASS ended...\n");
-      if (strncmp(buffer, "GNOME_SUDO_PASS", 15) == 0)
+      if (strncmp(buffer, "GNOME_SUDO_PASS", 15) == 0 || strncmp(buffer, "Password or swi", 15) == 0)
 	  gchar *password = NULL;
 	  gboolean prompt_grab;


Integration in KDE and kdm seems not to be easily possible now. There is a filed bug at where you can vote for this.

Moreover, kdm in openSUSE 10.3 crashes when pam_thinkfinger is enabled. A possible "workaround" is downgrading to thinkfinger 0.2.2.

Another workaround is to use Fprint from [4] which works quite nicely on my X61s and Kubuntu Hardy.

This Howto was copied from Installing Ubuntu 6.06 on a ThinkPad T43#Fingerprint_Reader and then slightly modified.