.\" Copyright (c) 2001 Mark R V Murray
.\" All rights reserved.
.\" Copyright (c) 2001 Networks Associates Technology, Inc.
.\" All rights reserved.
.\"
.\" This software was developed for the FreeBSD Project by ThinkSec AS and
.\" NAI Labs, the Security Research Division of Network Associates, Inc.
.\" under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
.\" DARPA CHATS research program.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. The name of the author may not be used to endorse or promote
.\"    products derived from this software without specific prior written
.\"    permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" $FreeBSD$
.\"
.Dd May 15, 2002
.Dt PAM_KSU 8
.Os
.Sh NAME
.Nm pam_ksu
.Nd Kerberos 5 SU PAM module
.Sh SYNOPSIS
.Op Ar service-name
.Ar module-type
.Ar control-flag
.Pa pam_ksu
.Op Ar options
.Sh DESCRIPTION
The Kerberos 5 SU authentication service module for PAM,
.Nm
for only one PAM category: authentication.
In terms of the
.Ar module-type
parameter, this is the
.Dq Li auth
feature.
The module is specifically designed to be used with the
.Xr su 1
utility.
.\" It also provides a null function for session management.
.Ss Kerberos 5 SU Authentication Module
The Kerberos 5 SU authentication component provides functions to verify
the identity of a user
.Pq Fn pam_sm_authenticate ,
and determine whether or not the user is authorized to obtain the
privileges of the target account.
If the target account is
.Dq root ,
then the Kerberos 5 principal used
for authentication and authorization will be the
.Dq root
instance of
the current user, e.g.\&
.Dq Li user/root@REAL.M .
Otherwise, the principal will simply be the current user's default
principal, e.g.\&
.Dq Li user@REAL.M .
.Pp
The user is prompted for a password if necessary.
Authorization is performed
by comparing the Kerberos 5 principal with those listed in the
.Pa .k5login
file in the target account's home directory
(e.g.\&
.Pa /root/.k5login
for root).
.Pp
The following options may be passed to the authentication module:
.Bl -tag -width ".Cm use_first_pass"
.It Cm debug
.Xr syslog 3
debugging information at
.Dv LOG_DEBUG
level.
.It Cm use_first_pass
If the authentication module
is not the first in the stack,
and a previous module
obtained the user's password,
that password is used
to authenticate the user.
If this fails,
the authentication module returns failure
without prompting the user for a password.
This option has no effect
if the authentication module
is the first in the stack,
or if no previous modules
obtained the user's password.
.It Cm try_first_pass
This option is similar to the
.Cm use_first_pass
option,
except that if the previously obtained password fails,
the user is prompted for another password.
.El
.Sh SEE ALSO
.Xr su 1 ,
.Xr syslog 3 ,
.Xr pam.conf 5 ,
.Xr pam 8