table of contents
PAM_TALLY2(8) | Linux-PAM Manual | PAM_TALLY2(8) |
NAME¶
pam_tally2 - The login counter (tallying) moduleSYNOPSIS¶
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 OPTIONSThis can be used for auth and account
module types.
onerr=[fail|succeed]
AUTH OPTIONS
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).
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
ACCOUNT OPTIONS
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 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_ERRA 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/tallylogfailure count logging file
SEE ALSO¶
pam.conf(5), pam.d(5), pam(8)AUTHOR¶
pam_tally2 was written by Tim Baverstock and Tomas Mraz.09/19/2013 | Linux-PAM Manual |