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]
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 users' 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).
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
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
pam.conf(5), pam.d(5), pam(8)
AUTHOR
pam_tally2 was written by Tim Baverstock and Tomas Mraz.
Linux-PAM Manual 09/19/2013 PAM_TALLY2(8)
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