Dear Maintainer,

When I upgraded the libpam-fprintd package to 1.90.1-2 (from 0.8.1-2​¹​),
fingerprint scanning stopped working for many things, including login,
sudo, and systemctl (but still worked for GDM and GNOME). I figured out
that this was because the pam_fprintd.so method had been removed from
/etc/pam.d/common-auth. After using pam-auth-update to re-add fprintd,
everything worked as expected.

The upgrade should not have removed the pam_fprintd.so method from
/etc/pam.d/common-auth. Indeed, I see no reason why that file should be
modified at all.

I set the severity of this bug to important, since removing fprintd from
common-auth breaks many things, and the cause of the problem is not
obvious. Feel free to downgrade if you disagree.

The best solution, in my opinion, would be to stop further updates from
modifying common-auth. At the very least, something should be added to
NEWS.Debian indicating that pam-auth-update will need to be re-run in
order to have fingerprints working again.

Also, it's possible that a different package upgrade caused the config
file to change, but this package seems the likeliest candidate.

Thanks,
Asher


Footnotes:
​¹​  I had been using an old version because of other problems. See
   #949165.