pam_tally2(8) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | MODULE TYPES PROVIDED | RETURN VALUES | NOTES | EXAMPLES | FILES | SEE ALSO | AUTHOR | COLOPHON

PAM_TALLY2(8)               Linux-PAM Manual               PAM_TALLY2(8)

NAME         top

       pam_tally2 - The login counter (tallying) module

SYNOPSIS         top

       pam_tally2.so [file=/path/to/counter] [onerr=[fail|succeed]]
                     [magic_root] [even_deny_root] [deny=n]
                     [lock_time=n] [unlock_time=n] [root_unlock_time=n]
                     [serialize] [audit] [silent] [no_log_info] [debug]

       pam_tally2 [--file /path/to/counter] [--user username]
                  [--reset[=n]] [--quiet]

DESCRIPTION         top

       This module maintains a count of attempted accesses, can reset
       count on success, can deny access if too many attempts fail.

       pam_tally2 comes in two parts: pam_tally2.so and pam_tally2. The
       former is the PAM module and the latter, a stand-alone program.
       pam_tally2 is an (optional) application which can be used to
       interrogate and manipulate the counter file. It can display user
       counts, set individual counts, or clear all counts. Setting
       artificially high counts may be useful for blocking users without
       changing their passwords. For example, one might find it useful
       to clear all counts every midnight from a cron job.

       Normally, failed attempts to access root will not cause the root
       account to become blocked, to prevent denial-of-service: if your
       users aren't given shell accounts and root may only login via su
       or at the machine console (not telnet/rsh, etc), this is safe.

OPTIONS         top

       GLOBAL OPTIONS
           This can be used for auth and account module types.

           onerr=[fail|succeed]
               If something weird happens (like unable to open the
               file), return with PAM_SUCCESS if onerr=succeed is given,
               else with the corresponding PAM error code.

           file=/path/to/counter
               File where to keep counts. Default is /var/log/tallylog.

           audit
               Will log the user name into the system log if the user is
               not found.

           silent
               Don't print informative messages.

           no_log_info
               Don't log informative messages via syslog(3).

           debug
               Always log tally count when it is incremented as a debug
               level message to the system log.

       AUTH OPTIONS
           Authentication phase first increments attempted login counter
           and checks if user should be denied access. If the user is
           authenticated and the login process continues on call to
           pam_setcred(3) it resets the attempts counter.

           deny=n
               Deny access if tally for this user exceeds n.

           lock_time=n
               Always deny for n seconds after failed attempt.

           unlock_time=n
               Allow access after n seconds after failed attempt. If
               this option is used the user will be locked out for the
               specified amount of time after he exceeded his maximum
               allowed attempts. Otherwise the account is locked until
               the lock is removed by a manual intervention of the
               system administrator.

           magic_root
               If the module is invoked by a user with uid=0 the counter
               is not incremented. The sysadmin should use this for user
               launched services, like su, otherwise this argument
               should be omitted.

           even_deny_root
               Root account can become unavailable.

           root_unlock_time=n
               This option implies even_deny_root option. Allow access
               after n seconds to root account after failed attempt. If
               this option is used the root user will be locked out for
               the specified amount of time after he exceeded his
               maximum allowed attempts.

           serialize
               Serialize access to the tally file using locks. This
               option might be used only for non-multithreaded services
               because it depends on the fcntl locking of the tally
               file. Also it is a good idea to use this option only in
               such configurations where the time between auth phase and
               account or setcred phase is not dependent on the
               authenticating client. Otherwise the authenticating
               client will be able to prevent simultaneous
               authentications by the same user by simply artificially
               prolonging the time the file record lock is held.

       ACCOUNT OPTIONS
           Account phase resets attempts counter if the user is not
           magic root. This phase can be used optionally for services
           which don't call pam_setcred(3) correctly or if the reset
           should be done regardless of the failure of the account phase
           of other modules.

           magic_root
               If the module is invoked by a user with uid=0 the counter
               is not changed. The sysadmin should use this for user
               launched services, like su, otherwise this argument
               should be omitted.

MODULE TYPES PROVIDED         top

       The auth and account module types are provided.

RETURN VALUES         top

       PAM_AUTH_ERR
           A invalid option was given, the module was not able to
           retrieve the user name, no valid counter file was found, or
           too many failed logins.

       PAM_SUCCESS
           Everything was successful.

       PAM_USER_UNKNOWN
           User not known.

NOTES         top

       pam_tally2 is not compatible with the old pam_tally faillog file
       format. This is caused by requirement of compatibility of the
       tallylog file format between 32bit and 64bit architectures on
       multiarch systems.

       There is no setuid wrapper for access to the data file such as
       when the pam_tally2.so module is called from xscreensaver. As
       this would make it impossible to share PAM configuration with
       such services the following workaround is used: If the data file
       cannot be opened because of insufficient permissions (EACCES) the
       module returns PAM_IGNORE.

EXAMPLES         top

       Add the following line to /etc/pam.d/login to lock the account
       after 4 failed logins. Root account will be locked as well. The
       accounts will be automatically unlocked after 20 minutes. The
       module does not have to be called in the account phase because
       the login calls pam_setcred(3) correctly.

           auth     required       pam_securetty.so
           auth     required       pam_tally2.so deny=4 even_deny_root unlock_time=1200
           auth     required       pam_env.so
           auth     required       pam_unix.so
           auth     required       pam_nologin.so
           account  required       pam_unix.so
           password required       pam_unix.so
           session  required       pam_limits.so
           session  required       pam_unix.so
           session  required       pam_lastlog.so nowtmp
           session  optional       pam_mail.so standard

FILES         top

       /var/log/tallylog
           failure count logging file

SEE ALSO         top

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

AUTHOR         top

       pam_tally2 was written by Tim Baverstock and Tomas Mraz.

COLOPHON         top

       This page is part of the linux-pam (Pluggable Authentication
       Modules for Linux) project.  Information about the project can be
       found at ⟨http://www.linux-pam.org/⟩.  If you have a bug report
       for this manual page, see ⟨//www.linux-pam.org/⟩.  This page was
       obtained from the tarball Linux-PAM-1.3.0.tar.bz2 fetched from
       ⟨http://www.linux-pam.org/library/⟩ on 2021-04-01.  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

Linux-PAM Manual               04/01/2016                  PAM_TALLY2(8)