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Diffstat (limited to 'modules/pam_unix/pam_unix.8.xml')
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diff --git a/modules/pam_unix/pam_unix.8.xml b/modules/pam_unix/pam_unix.8.xml new file mode 100644 index 0000000..9f9c818 --- /dev/null +++ b/modules/pam_unix/pam_unix.8.xml @@ -0,0 +1,501 @@ +<?xml version="1.0" encoding='UTF-8'?> +<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN" + "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd"> + +<refentry id="pam_unix"> + + <refmeta> + <refentrytitle>pam_unix</refentrytitle> + <manvolnum>8</manvolnum> + <refmiscinfo class="sectdesc">Linux-PAM Manual</refmiscinfo> + </refmeta> + + <refnamediv id="pam_unix-name"> + <refname>pam_unix</refname> + <refpurpose>Module for traditional password authentication</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <cmdsynopsis id="pam_unix-cmdsynopsis"> + <command>pam_unix.so</command> + <arg choice="opt"> + ... + </arg> + </cmdsynopsis> + </refsynopsisdiv> + + <refsect1 id="pam_unix-description"> + + <title>DESCRIPTION</title> + + <para> + This is the standard Unix authentication module. It uses standard + calls from the system's libraries to retrieve and set account + information as well as authentication. Usually this is obtained + from the /etc/passwd and the /etc/shadow file as well if shadow is + enabled. + </para> + + <para> + The account component performs the task of establishing the status + of the user's account and password based on the following + <emphasis>shadow</emphasis> elements: expire, last_change, max_change, + min_change, warn_change. In the case of the latter, it may offer advice + to the user on changing their password or, through the + <emphasis remap='B'>PAM_AUTHTOKEN_REQD</emphasis> return, delay + giving service to the user until they have established a new password. + The entries listed above are documented in the <citerefentry> + <refentrytitle>shadow</refentrytitle><manvolnum>5</manvolnum> + </citerefentry> manual page. Should the user's record not contain + one or more of these entries, the corresponding + <emphasis>shadow</emphasis> check is not performed. + </para> + + <para> + The authentication component performs the task of checking the + users credentials (password). The default action of this module + is to not permit the user access to a service if their official + password is blank. + </para> + + <para> + A helper binary, <citerefentry> + <refentrytitle>unix_chkpwd</refentrytitle><manvolnum>8</manvolnum> + </citerefentry>, is provided + to check the user's password when it is stored in a read + protected database. This binary is very simple and will only + check the password of the user invoking it. It is called + transparently on behalf of the user by the authenticating + component of this module. In this way it is possible + for applications like <citerefentry> + <refentrytitle>xlock</refentrytitle><manvolnum>1</manvolnum> + </citerefentry> to work without + being setuid-root. The module, by default, will temporarily turn + off SIGCHLD handling for the duration of execution of the helper + binary. This is generally the right thing to do, as many applications + are not prepared to handle this signal from a child they didn't know + was <function>fork()</function>d. The <option>noreap</option> module + argument can be used to suppress this temporary shielding and may be + needed for use with certain applications. + </para> + + <para> + The maximum length of a password supported by the pam_unix module + via the helper binary is <emphasis>PAM_MAX_RESP_SIZE</emphasis> + - currently 512 bytes. The rest of the password provided by the + conversation function to the module will be ignored. + </para> + + <para> + The password component of this module performs the task of updating + the user's password. The default encryption hash is taken from the + <emphasis remap='B'>ENCRYPT_METHOD</emphasis> variable from + <emphasis>/etc/login.defs</emphasis> + </para> + + <para> + The session component of this module logs when a user logins + or leave the system. + </para> + + <para> + Remaining arguments, supported by others functions of this + module, are silently ignored. Other arguments are logged as + errors through <citerefentry> + <refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum> + </citerefentry>. + </para> + </refsect1> + + <refsect1 id="pam_unix-options"> + + <title>OPTIONS</title> + <variablelist> + <varlistentry> + <term> + <option>debug</option> + </term> + <listitem> + <para> + Turns on debugging via + <citerefentry> + <refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum> + </citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <option>audit</option> + </term> + <listitem> + <para> + A little more extreme than debug. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <option>quiet</option> + </term> + <listitem> + <para> + Turns off informational messages namely messages about + session open and close via + <citerefentry> + <refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum> + </citerefentry>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term> + <option>nullok</option> + </term> + <listitem> + <para> + The default action of this module is to not permit the + user access to a service if their official password is blank. + The <option>nullok</option> argument overrides this default. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>nullresetok</option> + </term> + <listitem> + <para> + Allow users to authenticate with blank password if password reset + is enforced even if <option>nullok</option> is not set. If password + reset is not required and <option>nullok</option> is not set the + authentication with blank password will be denied. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>try_first_pass</option> + </term> + <listitem> + <para> + Before prompting the user for their password, the module first + tries the previous stacked module's password in case that + satisfies this module as well. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>use_first_pass</option> + </term> + <listitem> + <para> + The argument <option>use_first_pass</option> forces the module + to use a previous stacked modules password and will never prompt + the user - if no password is available or the password is not + appropriate, the user will be denied access. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>nodelay</option> + </term> + <listitem> + <para> + This argument can be used to discourage the authentication + component from requesting a delay should the authentication + as a whole fail. The default action is for the module to + request a delay-on-failure of the order of two second. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>use_authtok</option> + </term> + <listitem> + <para> + When password changing enforce the module to set the new + password to the one 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> + <option>authtok_type=<replaceable>type</replaceable></option> + </term> + <listitem> + <para> + This argument can be used to modify the password prompt + when changing passwords to include the type of the password. + Empty by default. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>nis</option> + </term> + <listitem> + <para> + NIS RPC is used for setting new passwords. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>remember=<replaceable>n</replaceable></option> + </term> + <listitem> + <para> + The last <replaceable>n</replaceable> passwords for each + user are saved in <filename>/etc/security/opasswd</filename> + in order to force password change history and keep the user + from alternating between the same password too frequently. + The MD5 password hash algorithm is used for storing the + old passwords. + Instead of this option the <command>pam_pwhistory</command> + module should be used. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>shadow</option> + </term> + <listitem> + <para> + Try to maintain a shadow based system. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>md5</option> + </term> + <listitem> + <para> + When a user changes their password next, encrypt + it with the MD5 algorithm. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>bigcrypt</option> + </term> + <listitem> + <para> + When a user changes their password next, + encrypt it with the DEC C2 algorithm. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>sha256</option> + </term> + <listitem> + <para> + When a user changes their password next, + encrypt it with the SHA256 algorithm. The + SHA256 algorithm must be supported by the <citerefentry> + <refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum> + </citerefentry> function. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>sha512</option> + </term> + <listitem> + <para> + When a user changes their password next, + encrypt it with the SHA512 algorithm. The + SHA512 algorithm must be supported by the <citerefentry> + <refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum> + </citerefentry> function. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>blowfish</option> + </term> + <listitem> + <para> + When a user changes their password next, + encrypt it with the blowfish algorithm. The + blowfish algorithm must be supported by the <citerefentry> + <refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum> + </citerefentry> function. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>gost_yescrypt</option> + </term> + <listitem> + <para> + When a user changes their password next, + encrypt it with the gost-yescrypt algorithm. The + gost-yescrypt algorithm must be supported by the <citerefentry> + <refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum> + </citerefentry> function. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>yescrypt</option> + </term> + <listitem> + <para> + When a user changes their password next, + encrypt it with the yescrypt algorithm. The + yescrypt algorithm must be supported by the <citerefentry> + <refentrytitle>crypt</refentrytitle><manvolnum>3</manvolnum> + </citerefentry> function. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>rounds=<replaceable>n</replaceable></option> + </term> + <listitem> + <para> + Set the optional number of rounds of the SHA256, SHA512, + blowfish, gost-yescrypt, and yescrypt password hashing + algorithms to + <replaceable>n</replaceable>. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>broken_shadow</option> + </term> + <listitem> + <para> + Ignore errors reading shadow information for + users in the account management module. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>minlen=<replaceable>n</replaceable></option> + </term> + <listitem> + <para> + Set a minimum password length of <replaceable>n</replaceable> + characters. The max. for DES crypt based passwords are 8 + characters. + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> + <option>no_pass_expiry</option> + </term> + <listitem> + <para> + When set ignore password expiration as defined by the + <emphasis>shadow</emphasis> entry of the user. The option has an + effect only in case <emphasis>pam_unix</emphasis> was not used + for the authentication or it returned authentication failure + meaning that other authentication source or method succeeded. + The example can be public key authentication in + <emphasis>sshd</emphasis>. The module will return + <emphasis remap='B'>PAM_SUCCESS</emphasis> instead of eventual + <emphasis remap='B'>PAM_NEW_AUTHTOK_REQD</emphasis> or + <emphasis remap='B'>PAM_AUTHTOK_EXPIRED</emphasis>. + </para> + </listitem> + </varlistentry> + </variablelist> + <para> + Invalid arguments are logged with <citerefentry> + <refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum> + </citerefentry>. + </para> + </refsect1> + + <refsect1 id="pam_unix-types"> + <title>MODULE TYPES PROVIDED</title> + <para> + All module types (<option>account</option>, <option>auth</option>, + <option>password</option> and <option>session</option>) are provided. + </para> + </refsect1> + + <refsect1 id='pam_unix-return_values'> + <title>RETURN VALUES</title> + <variablelist> + <varlistentry> + <term>PAM_IGNORE</term> + <listitem> + <para> + Ignore this module. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + + <refsect1 id='pam_unix-examples'> + <title>EXAMPLES</title> + <para> + An example usage for <filename>/etc/pam.d/login</filename> + would be: + <programlisting> +# Authenticate the user +auth required pam_unix.so +# Ensure users account and password are still active +account required pam_unix.so +# Change the user's password, but at first check the strength +# with pam_passwdqc(8) +password required pam_passwdqc.so config=/etc/passwdqc.conf +password required pam_unix.so use_authtok nullok yescrypt +session required pam_unix.so + </programlisting> + </para> + </refsect1> + + <refsect1 id='pam_unix-see_also'> + <title>SEE ALSO</title> + <para> + <citerefentry> + <refentrytitle>login.defs</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> + </para> + </refsect1> + + <refsect1 id='pam_unix-author'> + <title>AUTHOR</title> + <para> + pam_unix was written by various people. + </para> + </refsect1> + +</refentry> |