pam_tally2

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

NAME
       pam_tally2 - The login counter (tallying) module

SYNOPSIS
       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
       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
       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
       The auth and account module types are provided.

RETURN VALUES
       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
       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
       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
       /var/log/tallylog
           failure count logging file

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

AUTHOR
       pam_tally2 was written by Tim Baverstock and Tomas Mraz.

Linux-PAM Manual                  05/18/2017                     PAM_TALLY2(8)