Provided by: libpam-modules_1.3.1-5ubuntu11_amd64 
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] [debug]
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 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 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).
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 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.
even_deny_root
Root account can become unavailable.
root_unlock_time=n
This option implies even_deny_root option. Allow access after n seconds 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 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
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/tallylog
failure count logging file
SEE ALSO
pam.conf(5), pam.d(5), pam(7)
AUTHOR
pam_tally2 was written by Tim Baverstock and Tomas Mraz.