.\" $NetBSD: pam_unix.8,v 1.9 2019/12/23 17:51:57 reed Exp $
.\" 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
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.\"    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
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" $FreeBSD: src/lib/libpam/modules/pam_unix/pam_unix.8,v 1.11 2005/01/21 10:44:10 ru Exp $
.\"
.Dd February 26, 2005
.Dt PAM_UNIX 8
.Os
.Sh NAME
.Nm pam_unix
.Nd UNIX PAM module
.Sh SYNOPSIS
.Op Ar service-name
.Ar module-type
.Ar control-flag
.Pa pam_unix
.Op Ar options
.Sh DESCRIPTION
The
.Ux
authentication service module for PAM
provides functionality for two PAM categories:
authentication
and account management.
In terms of the
.Ar module-type
parameter, they are the
.Dq Li auth
and
.Dq Li account
features.
It also provides a null function for session management.
.Ss UNIX Authentication Module
The
.Ux
authentication component
provides functions to verify the identity of a user
.Pq Fn pam_sm_authenticate ,
which obtains the relevant
.Xr passwd 5
entry.
It prompts the user for a password
and verifies that this is correct with
.Xr crypt 3 .
.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.
.It Cm auth_as_self
This option will require the user
to authenticate himself as the user
given by
.Xr getlogin 2 ,
not as the account they are attempting to access.
This is primarily for services like
.Xr su 1 ,
where the user's ability to retype
their own password
might be deemed sufficient.
.It Cm nullok
If the password database
has no password
for the entity being authenticated,
then this option
will forgo password prompting,
and silently allow authentication to succeed.
.\" XXX This is not currently implemented.  It's debatable whether or not
.\" XXX it should be.
.\" .It Cm passwd_db Ns = Ns Ar name
.\" Use only the specified password database.
.\" Valid password database names are:
.\" .Bl -tag -width files
.\" .It files
.\" local password file
.\" .It nis
.\" NIS password database
.\" .El
.\" .Pp
.\" If the user does not exist in the specified password database or if the
.\" system is not configured to use the specified password database, an
.\" authentication failure will occur.
.El
.Ss UNIX Account Management Module
The
.Ux
account management component
provides a function to perform account management,
.Fn pam_sm_acct_mgmt .
The function verifies
that the authenticated user
is allowed to login to the local user account
by checking the password expiry date.
.Pp
The following options may be passed to the management module:
.Bl -tag -width ".Cm use_first_pass"
.It Cm debug
.Xr syslog 3
debugging information at
.Dv LOG_DEBUG
level.
.El
.Ss UNIX Password Management Module
The
.Ux
password management component
provides a function to perform account management,
.Fn pam_sm_chauthtok .
The function changes
the user's password.
.Pp
The following options may be passed to the password module:
.Bl -tag -width ".Cm use_first_pass"
.It Cm debug
.Xr syslog 3
debugging information at
.Dv LOG_DEBUG
level.
.It Cm no_warn
suppress warning messages to the user.
These messages include
reasons why the user's
authentication attempt was declined.
.It Cm passwd_db Ns = Ns Ar name
Change the user's password only the specified password database.
Valid password database names are:
.Bl -tag -width files
.It files
local password file
.It nis
NIS password database
.El
.El
.Sh FILES
.Bl -tag -width ".Pa /etc/master.passwd" -compact
.It Pa /etc/master.passwd
default
.Ux
password database.
.El
.Sh SEE ALSO
.Xr passwd 1 ,
.Xr getlogin 2 ,
.Xr crypt 3 ,
.Xr getpwent 3 ,
.Xr syslog 3 ,
.Xr nsswitch.conf 5 ,
.Xr passwd 5 ,
.Xr nis 8 ,
.Xr pam 8