How to enable integrated fingerprint reader with BioAPI

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Revision as of 11:49, 21 November 2005 by Thinker (Talk | contribs) (pam_bioapi isn't GDM-specific)
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This page describes the process of getting the fingerprint reader to work. It is based on experiences in Ubuntu on a T43. The same works on Fedora 4, SuSE 10, and Gentoo.

Basic driver installation

Getting required libs and tools

Installing the bioapi framework

Binary packages
  • If you're using Debian Sid (the unstable branch) you can try the packages from Michael R. Crusoe's site, either version 1.2.3 (recommended) or older versions which might not work with the steps in this howto.
Gentoo

You can either Grab the ebuild from http://www.qrivy.net/~michael/blua/bioapi/bioapi-1.2.2.ebuild.tar.bz2, or use the source-install procedure below.

Installing from source
  • Get the bioapi source:
$ wget http://www.qrivy.net/~michael/blua/bioapi/bioapi-1.2.2.tar.bz2
  • I could not compile bioapi with the graphical Qt tools. To do it manually, do the following:
$ tar xjf bioapi-1.2.2.tar.bz2
$ cd bioapi-1.2.2
$ ./configure --with-Qt-dir=no
$ make
and then as root
# make install
If make install fails, be sure you're root and then:
# export LD_LIBRARY_PATH=/usr/local/lib
# make install
and if you want to compile pam_bioapi for auth later
# cp include/bioapi_util.h include/installdefs.h imports/cdsa/v2_0/inc/cssmtype.h /usr/include
Be aware that checkinstall will not work!
(I got through configure with Qt, but got a cryptic build error. It all worked fine with Qt disabled as above)

Installing the driver

# sh install.sh
If that fails, it may be that make install failed up above -- try setting LD_LIBRARY_PATH, do the make install again, and come back here and try this again
  • If you want to use PAM-aware applications like xscreensaver that are NOT running with root permissions (as opposed to login, gdm or other authentication mechanisms), do the following as root (this doesn't seem necessary on SuSE 10):
# chmod 777 -R /usr/local/var/bioapi/
Actually this depends on where you installed, if you did as suggested, it should work. Otherwise you probably know what you're doing anyways. :)
# touch /var/log/BSP.log && chmod 666 /var/log/BSP.log
# chmod -R a+X /proc/bus/usb
# chmod 666 /proc/bus/usb/`/sbin/lsusb | sed -ne "/0483:2016/s/Bus\ \(.*\)\ Device\ \(.*\):\ .*/\1\/\2/p"`
It might be nessecary to put the above line into a startup script somewhere.

Testing the driver

Go to the folder where you extracted TFMESS_BSP_LIN_1.0beta2.zip and do:

# cd NonGUI_Sample
# chmod +x Sample
# ./Sample
Note that Sample may only run as root
You can try to "e"nroll (to record a fingerprint for an account) and then "v"erify (to test a fingerprint against the one it expects for an account)
You'll save a step later if you user your own login username as the username to enroll here

Login via pam_bioapi

The following explains how to add fingerprint authentiation to programs that use the PAM (Pluggable Authentication Modules) framework, such as the Gnome's GDM and KDE's KDM and screensaver.

Getting required libs & tools

Installing pam_bioapi

  • Prerequisites
On SuSE 10, I needed to install the pam-devel RPM
  • Get and compile the pam_bioapi module.
$ wget http://www.qrivy.net/~michael/blua/pam_bioapi/pam_bioapi-0.2.1.tar.bz2
$ tar xjf pam_bioapi-0.2.1.tar.bz2
$ cd pam_bioapi-0.2.1
$ wget http://badcode.de/downloads/fingerprint.patch
$ patch -p0 < fingerprint.patch
If you want to, review the patch. In general you should review all code you download and compile, if possible. The patch comes from this thread.
$ ./configure && make
NOTE!
If encountering 'rpl_malloc' symbol, remove the related term in the makefile. (FC3)
and as root
# make install
# cp /usr/local/lib/security/* /lib/security/
  • Use the sample tool from the fingerprint reader to create <username>.bir (<username> must be the username you want to login with. gdm will probably break for any login name that has no .bir file).
  • As root do:
# SERIAL=`BioAPITest | sed -ne "/Fingerprint/{n;n;s/^.*: \(.\{9\}\)\(.\{4\}\)\(.\{4\}\)\(.\{4\}\)\(.*\)/\1-\2-\3-\4-\5/gp}"`
# echo $SERIAL should print something like {5550454b-2054-464d-2f45-535320425350} now.
If it does, do:
# mkdir -p /etc/bioapi1.10/pam/$SERIAL
# cp <username>.bir /etc/bioapi1.10/pam/$SERIAL

Configuring pam

The following part is distribution specific. On Ubuntu or SuSE you can modify /etc/pam.d/common-auth (on Gentoo and Fedora it is /etc/pam.d/system-auth) to look like this: 

#
# /etc/pam.d/common-auth - authentication settings common to all services
#
# This file is included from other service-specific PAM config files,
# and should contain a list of the authentication modules that define
# the central authentication scheme for use on the system
# (e.g., /etc/shadow, LDAP, Kerberos, etc.).  The default is to use the
# traditional Unix authentication mechanisms.
#
auth       sufficient   pam_bioapi.so {5550454b-2054-464d-2f45-535320425350} /etc/bioapi1.10/pam/
password   sufficient   pam_bioapi.so {5550454b-2054-464d-2f45-535320425350} /etc/bioapi1.10/pam/
auth       required     pam_unix.so nullok_secure

With this modification pam immediately starts to use the fingerprint reader to do local authorization (e.g. sudo/gdm use the fingerprint reader).

Note: With a system-auth like above, Gentoo will probably give you 'account expired' errors. Edit /etc/pam.d/common-auth to look like this. 

account    required     pam_unix.so
auth       sufficient   pam_bioapi.so {5550454b-2054-464d-2f45-535320425350} /etc/bioapi1.10/pam/
password   sufficient   pam_bioapi.so {5550454b-2054-464d-2f45-535320425350} /etc/bioapi1.10/pam/
auth       required     pam_unix.so nullok_secure
session    required     pam_limits.so
session    required     pam_uni


Note that if su/sudo expects to receive the root password (SuSE 10), you need to have fingerprint settings for root (that is, copy in a root.bir as well as a your-username.bir). Otherwise, they get a segmentation fault. Which is a little unfortunate, given that you need to su or sudo to change your settings...

For some applications (kdm, SuSE 10 KDE screen saver), you'll need to enter an empty password (or select the correct user and then enter an empty password) in order to get the fingerprint prompt. kdm didn't give any visual indication it was going to the fingerprint reader, other than the cursor stopped blinking, but I swiped, and it let me in.

Note that sshd may pick up the fingerprint settings from /etc/pam.d/common-auth. I didn't want that, so I removed the "auth include common-auth" line from /etc/pam.d/sshd and replaced it with the lines that were originally in my /etc/pam.d/common-auth. That way most local services use the fingerprint reader, but sshd does not.

NOTE!
This was discovered through trial and success, if it is plain wrong, wikorrect it, please.

On Fedora, you may need to add /usr/local/lib to your LD_LIBRARY path so that the libraries referenced from pam_bioapi.so get picked up properly. Also the original 'session' terms in /etc/pam.d/system-auth need to be kept.

Now gdm should pop up an (ugly) image to swipe your finger and... magic - you can login without a password.

Make xscreensaver use the scanner

  • Get the needed xscreensaver sources:
$ wget http://www.jwz.org/xscreensaver/xscreensaver-4.23.tar.gz
$ tar xzf xscreensaver-4.23.tar.gz
$ cd xscreensaver-4.23
$ wget http://nax.hn.org/pub/bioapi/xscreensaver-4.22_alternativeAuth.diff
  • After reviewing the patch (it's small and straightforward), do
$ patch -p1 < xscreensaver-4.22_alternativeAuth.diff
The patch prevents xscreensaver from opening an authentification window and dispatches the authentification request to another program, in our case pam and pam_bioapi. It should apply with some offset, don't mind that. If it says something about rejected though, then there's a problem.
  • Compile with
$ ./configure --with-pam && make
  • If you recieve an error like "undefined reference to `XmuPrintDefaultErrorMessage'" then install the libxmu-dev package and run the previous line again
  • and then install as root with
$ su -c make install .
  • Make sure that the newly compiled xscreensaver is used:
$ which xscreensaver should return
/usr/local/bin/xscreensaver .
  • In case it doesn't, try
$ export PATH=/usr/local/bin:$PATH
and retry.
  • Kill the running instance of xscreensaver:
$ xscreensaver-command -exit
  • Make sure you have the following line in your ~/.xscreensaver:
alternativeAuth: True
  • Now edit /etc/pam.d/xscreensaver to include the following line (If you're on Ubuntu Breezy and you already changed /etc/pam.d/common-auth you should not need to do this.):
auth    sufficient      pam_bioapi.so {5550454b-2054-464d-2f45-535320425350} /etc/bioapi1.10/pam/
  • Start the new xscreensaver
$ xscreensaver
There should be a splash screen with version 4.23.
  • Now try:
$ xscreensaver-command -lock

If you have questions or problems with this procedure, ask: t43fingerprint (at) badcode.de .

Package for Debian sid

If you're running Debian sid (the unstable branch) you can also try the patched .deb-package (built from current Debian sources fetched with apt-get source) from this page, which also has Debian-specific instructions on how to setup the fingerprint reader. Use it on your own risk.

Troubleshooting and Hints

  1. After installing the driver, don't forget to reboot!
    1. This might not be necessary. it worked here without having to reboot.
  2. To see if the fingerprint device is know on the USB bus do:
# /sbin/lsusb
as root and you should see a line like:
Bus 003 Device 004: ID 0483:2016 SGS Thomson Microelectronics
The bus and device number can be different. This should work without the driver installed. If the device does not show up, you have a hardware problem/quirk, Rebooting might fix this.
  1. For some installation, after installing the driver as in section Installing the driver and making´sure the device is recognized, try to test it by going to NonGUI_Sample directory and run # ./Sample, one get segmentation fault. In this case, try getting the Beta1 instead of Beta2 of the driver and installing it
  2. There was some confusion about the /etc/bioapi1.10/pam{5550454b-2054-464d-2f45-535320425350} path, this has been fixed in the howto, if you have problems, check the section again, the path needs to have the '-' in them
  3. When something goes wrong look at the tail of /var/log/auth.log. Specifically if you see an entry saying something like
pam_bioapi[10480]: Unable to load BioAPI BSP with UUID of {5550454b-2054-464d-2f45-535320425350}, BioAPI error #194d.

Check whether your /proc/bus/usb directory permissions are set up as in the section Installing the driver.

  1. To get the xscreensaver compiled you might need a bunch of header files, in my case I need the following:
    • python-gtk2-dev
    • libgstreamer0.8-dev
    • xlibs-dev
  2. Sometimes $HOME/.xscreensaver got overwritten, try changing it to read-only.
  3. If after suspending to RAM and resume, lsusb no longer have "SGS Thomson Microelectronics" entry, try adding a line
# /etc/init.d/hotplug restart

to your /etc/acpi/resume.sh file

  1. If after resume lsusb shows the device but xscreensaver does not ask for fingerprint for login, you might want to check the permission of the usb bus in the appropriate /proc/bus/usb/ entry. If necessesary you might need to add a line to /etc/acpi/resume.sh as in section Installing the driver to set the permission right.

If it still doesn't work, ask me for help (and make sure all usefull stuff makes it back into this wiki :) to get a starting point as to where your problem is please include the output of:

$ lsusb
$ ldconfig -p
# updatedb && locate bioapi

t43fingerprint (at) badcode.de

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