NAME
pam_tally - The login counter (tallying) module
SYNOPSIS
pam_tally.so [file=/path/to/counter] [onerr=[fail|succeed]]
[magic_root] [even_deny_root_account] [deny=n]
[lock_time=n] [unlock_time=n] [per_user] [no_lock_time]
[no_reset] [audit] [silent] [no_log_info]
pam_tally [--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_tally comes in two parts: pam_tally.so and pam_tally. The former is
the PAM module and the latter, a stand-alone program. pam_tally 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. The
faillog(8) command can be used instead of pam_tally to to maintain the
counter file.
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/faillog.
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 checks if user should be denied access
and if not it increments attempted login counter. Then 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.
no_lock_time
Do not use the .fail_locktime field in /var/log/faillog for
this user.
no_reset
Don't reset count on successful entry, only decrement.
even_deny_root_account
Root account can become unavailable.
per_user
If /var/log/faillog contains a non-zero
.fail_max/.fail_locktime field for this user then use it
instead of deny=n/ lock_time=n parameter.
no_lock_time
Don't use .fail_locktime filed in /var/log/faillog for this
user.
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 incremented. The sysadmin should use this for user launched
services, like su, otherwise this argument should be omitted.
no_reset
Don't reset count on successful entry, only decrement.
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.
EXAMPLES
Add the following line to /etc/pam.d/login to lock the account after
too many failed logins. The number of allowed fails is specified by
/var/log/faillog and needs to be set with pam_tally or faillog(8)
before.
auth required pam_securetty.so
auth required pam_tally.so per_user
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/faillog
failure logging file
SEE ALSO
faillog(8), pam.conf(5), pam.d(5), pam(7)
AUTHOR
pam_tally was written by Tim Baverstock and Tomas Mraz.