pam_tally2: The login counter (tallying) module - Linux Manuals (8) (2024)

pam_tally2 comes in two parts:pam_tally2.soandpam_tally2. The former is the PAM module and the latter, a stand-alone program.pam_tally2is 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 accessrootwillnotcause the root account to become blocked, to prevent denial-of-service: if your users aren't given shell accounts and root may only login viasuor at the machine console (not telnet/rsh, etc), this is safe.

OPTIONS

GLOBAL OPTIONS

This can be used forauthandaccountmodule types.

onerr=[fail|succeed]

If something weird happens (like unable to open the file), return withPAM_SUCCESSifonerr=succeedis given, else with the corresponding PAM error code.

file=/path/to/counter

File where to keep counts. Default is/var/log/tallylog.

audit

See Also

How to Use Edit Log in TallyPrime - All You Need to Knowpam_tally2: lock user account after X failed login attempts in Linux | GoLinuxCloudpam_tally2 and tallylogpam_tally2(8) - Linux manual page

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 viasyslog(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 topam_setcred(3)it resets the attempts counter.

deny=n

Deny access if tally for this user exceedsn.

lock_time=n

Always deny fornseconds after failed attempt.

unlock_time=n

Allow access afternseconds 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, likesu, otherwise this argument should be omitted.

even_deny_root

Root account can become unavailable.

root_unlock_time=n

This option implieseven_deny_rootoption. Allow access afternseconds 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 isnotmagic root. This phase can be used optionally for services which don't callpam_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, likesu, otherwise this argument should be omitted.

MODULE TYPES PROVIDED

Theauthandaccountmodule 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 thepam_tally2.somodule 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 returnsPAM_IGNORE.

EXAMPLES

Add the following line to/etc/pam.d/loginto 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 thelogincallspam_setcred(3)correctly.

auth required pam_securetty.soauth required pam_tally2.so deny=4 even_deny_root unlock_time=1200auth required pam_env.soauth required pam_unix.soauth required pam_nologin.soaccount required pam_unix.sopassword required pam_unix.sosession required pam_limits.sosession required pam_unix.sosession required pam_lastlog.so nowtmpsession optional pam_mail.so standard 

FILES

/var/log/tallylog

failure count logging file

AUTHOR

pam_tally2 was written by Tim Baverstock and Tomas Mraz.