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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | MODULE TYPES PROVIDED | RETURN VALUES | NOTES | EXAMPLES | FILES | SEE ALSO | AUTHOR | COLOPHON |
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.gz fetched from
⟨http://www.linux-pam.org/library/⟩ on 2017-07-05. 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)