pam_pwhistory(8)

PAM_PWHISTORY(8)               Linux-PAM Manual               PAM_PWHISTORY(8)

NAME
       pam_pwhistory - PAM module to remember last passwords

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

DESCRIPTION
       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.

OPTIONS
       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_cracklib 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.

MODULE TYPES PROVIDED
       Only the password module type is provided.

RETURN VALUES
       PAM_AUTHTOK_ERR
           No new password was entered, the user aborted password change or
           new password couldn't be set.

       PAM_IGNORE
           Password history was disabled.

       PAM_MAXTRIES
           Password was rejected too often.

       PAM_USER_UNKNOWN
           User is not known to system.

EXAMPLES
       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_cracklib:

           #%PAM-1.0
           password     required       pam_cracklib.so    retry=3
           password     required       pam_pwhistory.so   use_authtok
           password     required       pam_unix.so        use_authtok

FILES
       /etc/security/opasswd
           File with password history

SEE ALSO
       pam.conf(5), pam.d(5), pam(7) pam_get_authtok(3)

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

Linux-PAM Manual                  05/18/2017                  PAM_PWHISTORY(8)