pam_pwhistory

pam_pwhistory.so [debug] [use_authtok] [enforce_for_root] [remember=N] [retry=N] [authtok_type=STRING]

This module saves the last passwords for each user in order to force password change history and keep the user from alternating between the same password too frequently.

This module does not work together with kerberos. In general, it does not make much sense to use this module in conjunction with NIS or LDAP, since the old passwords are stored on the local machine and are not available on another machine for password history checking.

debug

Turns on debugging via syslog(3).

use_authtok

When password changing enforce the module to use the new password provided by a previously stacked password module (this is used in the example of the stacking of the pam_passwdqc module documented below).

enforce_for_root

If this option is set, the check is enforced for root, too.

remember=N

The last N passwords for each user are saved in /etc/security/opasswd. The default is 10. Value of 0 makes the module to keep the existing contents of the opasswd file unchanged.

retry=N

Prompt user at most N times before returning with error. The default is 1.

authtok_type=STRING

See pam_get_authtok(3) for more details.

Only the password module type is provided.

PAM_AUTHTOK_ERR

No new password was entered, the user aborted password change or new password couldnt be set.

PAM_IGNORE

Password history was disabled.

PAM_MAXTRIES

Password was rejected too often.

PAM_USER_UNKNOWN

User is not known to system.

An example password section would be:

#%PAM-1.0
password     required       pam_pwhistory.so
password     required       pam_unix.so        use_authtok
      

In combination with pam_passwdqc:

#%PAM-1.0
password     required       pam_passwdqc.so    config=/etc/passwdqc.conf
password     required       pam_pwhistory.so   use_authtok
password     required       pam_unix.so        use_authtok
      

/etc/security/opasswd

File with password history

pam.conf(5), pam.d(5), pam(8) pam_get_authtok(3)

pam_pwhistory was written by Thorsten Kukuk <kukuk@thkukuk.de>