<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="pam_pwhistory">
<refmeta>
<refentrytitle>pam_pwhistory</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class="source">Linux-PAM</refmiscinfo>
<refmiscinfo class="manual">Linux-PAM Manual</refmiscinfo>
</refmeta>
<refnamediv xml:id="pam_pwhistory-name">
<refname>pam_pwhistory</refname>
<refpurpose>PAM module to remember last passwords</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis xml:id="pam_pwhistory-cmdsynopsis" sepchar=" ">
<command>pam_pwhistory.so</command>
<arg choice="opt" rep="norepeat">
debug
</arg>
<arg choice="opt" rep="norepeat">
use_authtok
</arg>
<arg choice="opt" rep="norepeat">
enforce_for_root
</arg>
<arg choice="opt" rep="norepeat">
remember=<replaceable>N</replaceable>
</arg>
<arg choice="opt" rep="norepeat">
retry=<replaceable>N</replaceable>
</arg>
<arg choice="opt" rep="norepeat">
authtok_type=<replaceable>STRING</replaceable>
</arg>
<arg choice="opt" rep="norepeat">
file=<replaceable>/path/filename</replaceable>
</arg>
<arg choice="opt" rep="norepeat">
conf=<replaceable>/path/to/config-file</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 xml:id="pam_pwhistory-description">
<title>DESCRIPTION</title>
<para>
This module saves the last passwords for each user in order
to force password change history and keep the user from
alternating between the same password too frequently.
</para>
<para>
This module does not work together with kerberos. In general,
it does not make much sense to use this module in conjunction
with NIS or LDAP, since the old passwords are stored on the
local machine and are not available on another machine for
password history checking.
</para>
</refsect1>
<refsect1 xml:id="pam_pwhistory-options">
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term>
debug
</term>
<listitem>
<para>
Turns on debugging via
<citerefentry>
<refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
use_authtok
</term>
<listitem>
<para>
When password changing enforce the module to use the new password
provided by a previously stacked <option>password</option>
module (this is used in the example of the stacking of the
<command>pam_passwdqc</command> module documented below).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
enforce_for_root
</term>
<listitem>
<para>
If this option is set, the check is enforced for root, too.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
remember=N
</term>
<listitem>
<para>
The last <replaceable>N</replaceable> passwords for each
user are saved.
The default is <emphasis>10</emphasis>. Value of
<emphasis>0</emphasis> makes the module to keep the existing
contents of the <filename>opasswd</filename> file unchanged.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
retry=N
</term>
<listitem>
<para>
Prompt user at most <replaceable>N</replaceable> times
before returning with error. The default is
<emphasis>1</emphasis>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
authtok_type=STRING
</term>
<listitem>
<para>
See <citerefentry>
<refentrytitle>pam_get_authtok</refentrytitle><manvolnum>3</manvolnum>
</citerefentry> for more details.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
file=/path/filename
</term>
<listitem>
<para>
Store password history in file <filename>/path/filename</filename>
rather than the default location. The default location is
<filename>/etc/security/opasswd</filename>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
conf=/path/to/config-file
</term>
<listitem>
<para>
Use another configuration file instead of the default
<filename>/etc/security/pwhistory.conf</filename>.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
The options for configuring the module behavior are described in the
<citerefentry><refentrytitle>pwhistory.conf</refentrytitle>
<manvolnum>5</manvolnum></citerefentry> manual page. The options
specified on the module command line override the values from the
configuration file.
</para>
</refsect1>
<refsect1 xml:id="pam_pwhistory-types">
<title>MODULE TYPES PROVIDED</title>
<para>
Only the <option>password</option> module type is provided.
</para>
</refsect1>
<refsect1 xml:id="pam_pwhistory-return_values">
<title>RETURN VALUES</title>
<variablelist>
<varlistentry>
<term>PAM_AUTHTOK_ERR</term>
<listitem>
<para>
No new password was entered, the user aborted password
change or new password couldn't be set.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_IGNORE</term>
<listitem>
<para>
Password history was disabled.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_MAXTRIES</term>
<listitem>
<para>
Password was rejected too often.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_USER_UNKNOWN</term>
<listitem>
<para>
User is not known to system.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="pam_pwhistory-examples">
<title>EXAMPLES</title>
<para>
An example password section would be:
<programlisting>
#%PAM-1.0
password required pam_pwhistory.so
password required pam_unix.so use_authtok
</programlisting>
</para>
<para>
In combination with <command>pam_passwdqc</command>:
<programlisting>
#%PAM-1.0
password required pam_passwdqc.so config=/etc/passwdqc.conf
password required pam_pwhistory.so use_authtok
password required pam_unix.so use_authtok
</programlisting>
</para>
</refsect1>
<refsect1 xml:id="pam_pwhistory-files">
<title>FILES</title>
<variablelist>
<varlistentry>
<term>/etc/security/opasswd</term>
<listitem>
<para>Default file with password history</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>/etc/security/pwhistory.conf</filename></term>
<listitem>
<para>Config file for pam_pwhistory options</para>
</listitem>
</varlistentry>
<varlistentry condition="with_vendordir">
<term><filename>%vendordir%/security/pwhistory.conf</filename></term>
<listitem>
<para>
Config file for pam_pwhistory options. It will be used if
<filename>/etc/security/pwhistory.conf</filename> does not exist.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 xml:id="pam_pwhistory-see_also">
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>pwhistory.conf</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam.conf</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>
<citerefentry>
<refentrytitle>pam_get_authtok</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>
</para>
</refsect1>
<refsect1 xml:id="pam_pwhistory-author">
<title>AUTHOR</title>
<para>
pam_pwhistory was written by Thorsten Kukuk <kukuk@thkukuk.de>
</para>
</refsect1>
</refentry>