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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | MODULE TYPES PROVIDED | RETURN VALUES | NOTES | EXAMPLES | FILES | SEE ALSO | AUTHOR | COLOPHON |
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PAM_TALLY2(8) Linux-PAM Manual PAM_TALLY2(8)
pam_tally2 - The login counter (tallying) module
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]
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.
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.
The auth and account module types are provided.
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.
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.
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
/var/log/tallylog
failure count logging file
pam.conf(5), pam.d(5), pam(8)
pam_tally2 was written by Tim Baverstock and Tomas Mraz.
This page is part of the linux-pam (Pluggable Authentication
Modules for Linux) project. Information about the project can be
found at ⟨http://www.linux-pam.org/⟩. If you have a bug report
for this manual page, see ⟨//www.linux-pam.org/⟩. This page was
obtained from the tarball Linux-PAM-1.3.0.tar.bz2 fetched from
⟨http://www.linux-pam.org/library/⟩ on 2021-08-27. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
Linux-PAM Manual 04/01/2016 PAM_TALLY2(8)
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