pam_tally
The login counter (tallying) module
see also :
faillog
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]
add an example, a script, a trick and tips
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
source
INST_MODULES := pam_deny.so pam_permit.so
pam_limits.so pam_unix.so pam_nologin.so pam_rootok.so
pam_warn.so pam_tally.so
romfs:
$(ROMFSINST)
build/libpamc/.libs/libpamc.so.0.81.0 /lib/libpamc.so.0.81.0
$(ROMFSINST)
build/modules/pam_tally/.libs/pam_tally
/bin/pam_tally
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 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.
files
/var/log/faillog
failure logging file
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.
see also
faillog ,
pam.conf, pam.d, pam
author
pam_tally was
written by Tim Baverstock and Tomas Mraz.