Finding pam module

Question

I've started to read the documentation on pam and it says that the available modules should be stored in /lib/security or /lib/security64 for the examples they give to be applicable. My problem is that none of those directories contain the security subdirectory. However I do find the configuration file /etc/security/pam.conf and directory /etc/security/pam.d. Is there another place I can look for the modules? Maybe I don't need to be to concerned with them I honestly don't know since I haven't gotten very far into the documentation yet but I would like to be able to modify my authentications if so just for the fun of it. I'm running kubuntu 18.04.1.

Answer 1

The PAM modules themselves are shared object (.so) files whose location on Multiarch systems follows the same conventions as other libraries, depending on your procesor architecture i.e.

/lib/i386-linux-gnu
/lib/x86_64-linux-gnu
/usr/lib/i386-linux-gnu
/usr/lib/x86_64-linux-gnu

Ex.

$ ls /lib/x86_64-linux-gnu/security/
pam_access.so         pam_group.so      pam_namespace.so   pam_systemd.so
pam_cifscreds.so      pam_issue.so      pam_nologin.so     pam_tally2.so
pam_debug.so          pam_keyinit.so    pam_permit.so      pam_tally.so
pam_deny.so           pam_kwallet5.so   pam_pwhistory.so   pam_time.so
pam_echo.so           pam_lastlog.so    pam_rhosts.so      pam_timestamp.so
pam_env.so            pam_limits.so     pam_rootok.so      pam_tty_audit.so
pam_exec.so           pam_listfile.so   pam_securetty.so   pam_umask.so
pam_extrausers.so     pam_localuser.so  pam_selinux.so     pam_unix.so
pam_faildelay.so      pam_loginuid.so   pam_sepermit.so    pam_userdb.so
pam_filter.so         pam_mail.so       pam_shells.so      pam_warn.so
pam_ftp.so            pam_mkhomedir.so  pam_stress.so      pam_wheel.so
pam_gnome_keyring.so  pam_motd.so       pam_succeed_if.so  pam_xauth.so

See the Ubuntu MultiarchSpec: Filesystem Layout