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pam_tally — The login counter (tallying) module
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
DESCRIPTION
This module maintains a count of attempted accesses, can reset count on
success, can deny access if too many attempts fail.
pam_tally has several limitations, which are solved with pam_tally2. For this
reason pam_tally is deprecated and will be removed in a future release.
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 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. 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. The messages printed without the
silent option leak presence of accounts on the system because they are
not printed for non-existing accounts.
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.
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
AUTHOR
pam_tally was written by Tim Baverstock and Tomas Mraz.
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