ThinkFinger

Related articles
Fingerprint-gui
Fprint
ThinkFinger is a driver for the SGS Thomson Microelectronics fingerprint reader found in older IBM/Lenovo ThinkPads.
ThinkWiki has a
list of various fingerprint readers
found in ThinkPads. Newer models using different readers might not work with ThinkFinger.
Installation
Install
the
thinkfinger
AUR
package.
Configuration
The
uinput
module needs to be loaded.
TF-Tool
Use
tf-tool
to test ThinkFinger. You will have to run this as root because a direct access to the USB devices is needed.
Run
tf-tool --acquire
to generate a file at
/etc/pam_thinkfinger/test.bir
and
tf-tool --verify
to see if it identifies you correctly.
tf-tool --add-user <username>
acquires and stores your fingerprint in
/etc/pam_thinkfinger/<username>.bir
, which is needed for an authentication with PAM.
PAM
See
PAM
.
/etc/pam.d/login
Change the file
/etc/pam.d/login
to look like this if you want to use your fingerprint to authenticate yourself on logon:
/etc/pam.d/login
#%PAM-1.0
auth		sufficient	pam_thinkfinger.so
auth		required	pam_unix.so use_first_pass nullok_secure
account		required	pam_unix.so
password	required	pam_unix.so
session		required	pam_unix.so
/etc/pam.d/su
Change this file to confirm the
su
command with a finger-swipe:
/etc/pam.d/su
#%PAM-1.0
auth            sufficient      pam_rootok.so
auth		sufficient 	pam_thinkfinger.so
auth		required	pam_unix.so nullok_secure try_first_pass
account		required	pam_unix.so
session		required	pam_unix.so
Tip
Do not forget to do a
tf-tool --add-user root
to use this feature.
/etc/pam.d/sudo
Change this file to confirm the
sudo
command with a finger-swipe:
/etc/pam.d/su
#%PAM-1.0
auth		sufficient 	pam_thinkfinger.so
auth		required	pam_unix.so nullok_secure try_first_pass
auth		required	pam_nologin.so
/etc/pam.d/xscreensaver
The factual accuracy of this article or section is disputed.
Reason:
Tampering with files in
/usr/bin/
is a bad idea since these changes will get overwritten on an update (Discuss in
Talk:ThinkFinger
)
XScreensaver is a bit tricky. First, configure PAM with a file
/etc/pam.d/xscreensaver
containing:
/etc/pam.d/xscreensaver
auth            sufficient      pam_thinkfinger.so
 auth            required        pam_unix_auth.so try_first_pass
This still will not work because Xscreensaver cannot read/write from
/dev/misc/uinput
and
/dev/bus/usb*
. A
udev
rule must be written to authorize a new group read/write access.
First, create a new group, let us say
fingerprint
:
# groupadd fingerprint
Add the user you want to be able to unlock Xscreensaver with the fingerprint reader to the group:
# gpasswd -a <user> fingerprint
Logout and login again for the changes to take effect.
Next, search for
uinput
and
bus/usb
in your udev rules directory:
$ grep -in uinput /etc/udev/rules.d/*

/etc/udev/rules.d/udev.rules:222:KERNEL=="uinput",  NAME="misc/%k", SYMLINK+="%k"
/etc/udev/rules.d/udev.rules:263:KERNEL=="uinput", NAME="input/%k"
$ grep -in "bus/usb" /etc/udev/rules.d/*

/etc/udev/rules.d/udev.rules:318:SUBSYSTEM=="usb_device", ACTION=="add", PROGRAM="/bin/sh -c 'K=%k; K=$${K#usbdev};printf bus/usb/%%03i/%%03i $${K%%%%.*} $${K#*.}'", NAME="%c", MODE="0664"
/etc/udev/rules.d/udev.rules:320:SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0664"
Copy the lines you found with grep in the previous step to a new udev rules file:
/etc/udev/rules.d/99fingerprint.rules
KERNEL=="uinput",  NAME="misc/%k", SYMLINK+="%k", MODE="0660", GROUP="fingerprint"
SUBSYSTEM=="usb_device", ACTION=="add", PROGRAM="/bin/sh -c 'K=%k; K=$${K#usbdev};printf bus/usb/%%03i/%%03i $${K%%%%.*} $${K#*.}'", NAME="%c", MODE="0664", GROUP="fingerprint"
SUBSYSTEM=="usb", ACTION=="add", ENV{DEVTYPE}=="usb_device", NAME="bus/usb/$env{BUSNUM}/$env{DEVNUM}", MODE="0664", GROUP="fingerprint"
The difference between the rules in
/etc/udev/rules.d/99fingreprint.rules
and those in
/etc/udev/rules.d/udev.rules
should only be the addition of
MODE="0664", GROUP="fingerprint"
or
MODE="0660", GROUP="fingerprint"
at the end of the lines.
After adding the custom udev rules, you should give your user permissions to access their own fingerprint file:
$ chown $USERNAME:root /etc/pam_thinkfinger/$USERNAME.bir
$ chmod 400 /etc/pam_thinkfinger/$USERNAME.bir
$ chmod o+x /etc/pam_thinkfinger
Note
The last command is opening up a directory for execution to everyone, beware of the security implications this might have.
As a last step, you need to remove the root setuid from
/usr/bin/xscreensaver
, otherwise Xscreensaver will not be able to unlock with the fingerprint reader:
# chmod -s /usr/bin/xscreensaver
/etc/pam.d/gdm
Edit
/etc/pam.d/gdm
and add the following line to the top:
/etc/pam.d/gdm
auth		sufficient 	pam_thinkfinger.so
Then modify
auth required pam_unix.so
to look like this:
/etc/pam.d/gdm
auth		required	pam_unix.so use_first_pass nullok_secure
/etc/pam.d/xdm
Edit
/etc/pam.d/xdm
to look like this:
/etc/pam.d/xdm
#%PAM-1.0
auth            sufficient      pam_thinkfinger.so
auth            required        pam_unix.so use_first_pass nullok_secure
auth            required        pam_nologin.so
auth            required        pam_env.so
account         required        pam_unix.so
password        required        pam_unix.so
session         required        pam_unix.so
session         required        pam_limits.so
/etc/pam.d/slim
Append
the following to
/etc/pam.d/slim
:
/etc/pam.d/slim
#%PAM-1.0
...
auth            sufficient      pam_thinkfinger.so
auth            requisite       pam_nologin.so
auth            required        pam_env.so
auth            required        pam_unix.so
account         required        pam_unix.so
session         required        pam_limits.so
session         required        pam_unix.so
password        required        pam_unix.so
Now restart SLiM and you may use the fingerprinter to login.
Alternative fingerprint reader software
Fprint
is an alternative fingerprint reader software that works with some of the newer ThinkPad fingerprint readers.
See also
https://www.thinkwiki.org/wiki/Talk:How_to_enable_the_fingerprint_reader
https://thinkfinger.sourceforge.net/
https://bbs.archlinux.org/viewtopic.php?id=36134
https://www.thinkwiki.org/wiki/How_to_enable_the_fingerprint_reader_with_ThinkFinger
https://www.thinkwiki.org/index.php?title=Installing_Ubuntu_6.06_on_a_ThinkPad_T43#Fingerprint_Reader