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 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(8)
AUTHOR
pam_tally2 was written by Tim Baverstock and Tomas Mraz.
Linux-PAM Manual 09/19/2013 PAM_TALLY2(8)
Linux-Distributionen
Huschi als Linux-Admin