path: root/modules/pam_tally2/pam_tally2.8

'\" t
.\"     Title: pam_tally2
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 06/08/2020
.\"    Manual: Linux-PAM Manual
.\"    Source: Linux-PAM Manual
.\"  Language: English
.\"
.TH "PAM_TALLY2" "8" "06/08/2020" "Linux-PAM Manual" "Linux\-PAM Manual"
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.SH "NAME"
pam_tally2 \- The login counter (tallying) module
.SH "SYNOPSIS"
.HP \w'\fBpam_tally2\&.so\fR\ 'u
\fBpam_tally2\&.so\fR [file=\fI/path/to/counter\fR] [onerr=[\fIfail\fR|\fIsucceed\fR]] [magic_root] [even_deny_root] [deny=\fIn\fR] [lock_time=\fIn\fR] [unlock_time=\fIn\fR] [root_unlock_time=\fIn\fR] [serialize] [audit] [silent] [no_log_info] [debug]
.HP \w'\fBpam_tally2\fR\ 'u
\fBpam_tally2\fR [\-\-file\ \fI/path/to/counter\fR] [\-\-user\ \fIusername\fR] [\-\-reset[=\fIn\fR]] [\-\-quiet]
.SH "DESCRIPTION"
.PP
This module maintains a count of attempted accesses, can reset count on success, can deny access if too many attempts fail\&.
.PP
pam_tally2 comes in two parts:
\fBpam_tally2\&.so\fR
and
\fBpam_tally2\fR\&. The former is the PAM module and the latter, a stand\-alone program\&.
\fBpam_tally2\fR
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\&.
.PP
Normally, failed attempts to access
\fIroot\fR
will
\fBnot\fR
cause the root account to become blocked, to prevent denial\-of\-service: if your users aren\*(Aqt given shell accounts and root may only login via
\fBsu\fR
or at the machine console (not telnet/rsh, etc), this is safe\&.
.SH "OPTIONS"
.PP
GLOBAL OPTIONS
.RS 4
This can be used for
\fIauth\fR
and
\fIaccount\fR
module types\&.
.PP
\fBonerr=[\fR\fB\fIfail\fR\fR\fB|\fR\fB\fIsucceed\fR\fR\fB]\fR
.RS 4
If something weird happens (like unable to open the file), return with
\fBPAM_SUCCESS\fR
if
\fBonerr=\fR\fB\fIsucceed\fR\fR
is given, else with the corresponding PAM error code\&.
.RE
.PP
\fBfile=\fR\fB\fI/path/to/counter\fR\fR
.RS 4
File where to keep counts\&. Default is
/var/log/tallylog\&.
.RE
.PP
\fBaudit\fR
.RS 4
Will log the user name into the system log if the user is not found\&.
.RE
.PP
\fBsilent\fR
.RS 4
Don\*(Aqt print informative messages\&. The messages printed without the
\fIsilent\fR
option leak presence of accounts on the system because they are not printed for non\-existing accounts\&.
.RE
.PP
\fBno_log_info\fR
.RS 4
Don\*(Aqt log informative messages via
\fBsyslog\fR(3)\&.
.RE
.PP
\fBdebug\fR
.RS 4
Always log tally count when it is incremented as a debug level message to the system log\&.
.RE
.RE
.PP
AUTH OPTIONS
.RS 4
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
\fBpam_setcred\fR(3)
it resets the attempts counter\&.
.PP
\fBdeny=\fR\fB\fIn\fR\fR
.RS 4
Deny access if tally for this user exceeds
\fIn\fR\&.
.RE
.PP
\fBlock_time=\fR\fB\fIn\fR\fR
.RS 4
Always deny for
\fIn\fR
seconds after failed attempt\&.
.RE
.PP
\fBunlock_time=\fR\fB\fIn\fR\fR
.RS 4
Allow access after
\fIn\fR
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\&.
.RE
.PP
\fBmagic_root\fR
.RS 4
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
\fBsu\fR, otherwise this argument should be omitted\&.
.RE
.PP
\fBeven_deny_root\fR
.RS 4
Root account can become unavailable\&.
.RE
.PP
\fBroot_unlock_time=\fR\fB\fIn\fR\fR
.RS 4
This option implies
\fBeven_deny_root\fR
option\&. Allow access after
\fIn\fR
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\&.
.RE
.PP
\fBserialize\fR
.RS 4
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\&.
.RE
.RE
.PP
ACCOUNT OPTIONS
.RS 4
Account phase resets attempts counter if the user is
\fBnot\fR
magic root\&. This phase can be used optionally for services which don\*(Aqt call
\fBpam_setcred\fR(3)
correctly or if the reset should be done regardless of the failure of the account phase of other modules\&.
.PP
\fBmagic_root\fR
.RS 4
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
\fBsu\fR, otherwise this argument should be omitted\&.
.RE
.RE
.SH "MODULE TYPES PROVIDED"
.PP
The
\fBauth\fR
and
\fBaccount\fR
module types are provided\&.
.SH "RETURN VALUES"
.PP
PAM_AUTH_ERR
.RS 4
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\&.
.RE
.PP
PAM_SUCCESS
.RS 4
Everything was successful\&.
.RE
.PP
PAM_USER_UNKNOWN
.RS 4
User not known\&.
.RE
.SH "NOTES"
.PP
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\&.
.PP
There is no setuid wrapper for access to the data file such as when the
\fBpam_tally2\&.so\fR
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 (\fBEACCES\fR) the module returns
\fBPAM_IGNORE\fR\&.
.SH "EXAMPLES"
.PP
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
\fBlogin\fR
calls
\fBpam_setcred\fR(3)
correctly\&.
.sp
.if n \{\
.RS 4
.\}
.nf
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
    
.fi
.if n \{\
.RE
.\}
.SH "FILES"
.PP
/var/log/tallylog
.RS 4
failure count logging file
.RE
.SH "SEE ALSO"
.PP
\fBpam.conf\fR(5),
\fBpam.d\fR(5),
\fBpam\fR(8)
.SH "AUTHOR"
.PP
pam_tally2 was written by Tim Baverstock and Tomas Mraz\&.