Login with a GnuPG Smartcard and Poldi
Libpam-poldi allows you to use a GnuPG smartcard to log in your GNU/Linux system.
If you use Debian GNU/Linux libpam-poldi is already available in the
On Ubuntu GNU/Linux you can't use the Debian binaries but you can download the sources of libpam-poldi from Debian and than build a package for your Ubuntu system with 'dpkg-buildpackage -us -uc'.
First check if poldi detects your cardreader: 'poldi-ctrl -d'. Unfortunately some cardreader doesn’t work with poldi and the existing free driver. For example the cardma4040 needs the non-free driver from Omnikey.
If poldi successfully detected your cardreader you can start to configure poldi. Poldi has a pretty good documentation so i will keep my explanations rather short.
- Root has to register the new card for poldi:
poldi-ctrl --register-card --account <your-user-account> --serialno <serialno of your card>You can also execute this command without '--account <your-user-account>' but than the user want be able to install or update his card's keys.
The serialno can be found by executing 'gpg --card-status' and looking for "Application ID".
- Now we have to establish a mapping between the user and the smartcard he
poldi-ctrl --associate --account <your-user-account> --serialno <serialno of your card>
- Now you have to write your public key into the appropriate key file (you
have to do this within your user account)
- That's it, now you can test it with 'poldi-ctrl --test'
Now you have to tell pam, that you want to use poldi.
Therefore you have to edit the files in /etc/pam.d. If you want to use your smartcard with gdm than...
- make a backup of /etc/pam.d/gdm.
mv /etc/pam.d/gdm /etc/pam.d/gdm.default
- create a new /etc/pam.d/gdm which contains only one of these lines:
auth required pam_poldi.so quiet
Or if you want to login unattended, use
auth required pam_poldi.so try-pin=123456 quiet
Or if you want to fallback to regular unix passwords, use
auth sufficient pam_poldi.so try-pin=123456 quiet auth required pam_unix.so nullok_secure
Now you should be able to use your GnuPG smartcard to log in your GNU/Linux system.