To make the Lenovo Thinkpad t440s fingerprint scanner in Ubuntu (16.04.3) work, install the following:

sudo apt install fprintd libpam-fprintd

After the install – update the following file to set the timer to unlimited, otherwise the fingerprint scanner will time out during login:

sudo vi /etc/pam.d/common-auth

and look for the line that has the pam_fprintd in the name

auth [success=2 default=ignore] pam_fprintd.so max_tries=1 timeout=10

Usually the default is timeout=10 and max_tries=1, I updated mine like below, so it never times out and I have 2 tries

auth [success=2 default=ignore] pam_fprintd.so max_tries=2 timeout=-1

This works on sudo auth and login from lock, haven’t fully tested yet like startup etc. It is a little unstable though, I had it fail on me few times where it wouldn’t recognize the scanner anymore. I will update this post if I find anything.