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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
<refentry id="pam_get_authtok">
<refmeta>
<refentrytitle>pam_get_authtok</refentrytitle>
<manvolnum>3</manvolnum>
<refmiscinfo class='setdesc'>Linux-PAM Manual</refmiscinfo>
</refmeta>
<refnamediv id="pam_get_authtok-name">
<refname>pam_get_authtok</refname>
<refname>pam_get_authtok_verify</refname>
<refname>pam_get_authtok_noverify</refname>
<refpurpose>get authentication token</refpurpose>
</refnamediv>
<!-- body begins here -->
<refsynopsisdiv id="pam_get_authtok-synopsis">
<funcsynopsis>
<funcsynopsisinfo>#include <security/pam_ext.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>pam_get_authtok</function></funcdef>
<paramdef>pam_handle_t *<parameter>pamh</parameter></paramdef>
<paramdef>int <parameter>item</parameter></paramdef>
<paramdef>const char **<parameter>authtok</parameter></paramdef>
<paramdef>const char *<parameter>prompt</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>pam_get_authtok_noverify</function></funcdef>
<paramdef>pam_handle_t *<parameter>pamh</parameter></paramdef>
<paramdef>const char **<parameter>authtok</parameter></paramdef>
<paramdef>const char *<parameter>prompt</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>pam_get_authtok_verify</function></funcdef>
<paramdef>pam_handle_t *<parameter>pamh</parameter></paramdef>
<paramdef>const char **<parameter>authtok</parameter></paramdef>
<paramdef>const char *<parameter>prompt</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 id='pam_get_authtok-description'>
<title>DESCRIPTION</title>
<para>
The <function>pam_get_authtok</function> function returns the
cached authentication token, or prompts the user if no token is
currently cached. It is intended for internal use by Linux-PAM and
PAM service modules. Upon successful return,
<emphasis>authtok</emphasis> contains a pointer to the value of the
authentication token. Note, this is a pointer to the
<emphasis>actual</emphasis> data and should
<emphasis remap="B">not</emphasis> be <emphasis>free()</emphasis>'ed or
over-written!
</para>
<para>
The <emphasis>prompt</emphasis> argument specifies a prompt to use
if no token is cached. If a NULL pointer
is given, <function>pam_get_authtok</function> uses pre-defined prompts.
</para>
<para>
The following values are supported for <emphasis>item</emphasis>:
</para>
<variablelist>
<varlistentry>
<term>PAM_AUTHTOK</term>
<listitem>
<para>
Returns the current authentication token. Called from
<citerefentry><refentrytitle>pam_sm_chauthtok</refentrytitle><manvolnum>3</manvolnum>
</citerefentry> <function>pam_get_authtok</function> will
ask the user to confirm the new token by retyping it. If
a prompt was specified, "Retype" will be used as prefix.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_OLDAUTHTOK</term>
<listitem>
<para>
Returns the previous authentication token when changing
authentication tokens.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
The <function>pam_get_authtok_noverify</function> function can
only be used for changing the password
(from <citerefentry>
<refentrytitle>pam_sm_chauthtok</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>). It returns the cached
authentication token, or prompts the user if no token is
currently cached. The difference to <function>pam_get_authtok</function>
is, that this function does not ask a second time for the password
to verify it. Upon successful return, <emphasis>authtok</emphasis>
contains a pointer to the value of the authentication token. Note,
this is a pointer to the
<emphasis>actual</emphasis> data and should
<emphasis remap="B">not</emphasis> be <emphasis>free()</emphasis>'ed or
over-written!
</para>
<para>
The <function>pam_get_authtok_verify</function> function can
only be used to verify a password for mistypes gotten by
<citerefentry>
<refentrytitle>pam_get_authtok_noverify</refentrytitle><manvolnum>3</manvolnum>
</citerefentry>. This function asks a second time for the password
and verify it with the password provided by <emphasis>authtok</emphasis>
argument. In case of an error, the value of <emphasis>authtok</emphasis>
is undefined. Else this argument will point to the
<emphasis>actual</emphasis> data and should
<emphasis remap="B">not</emphasis> be <emphasis>free()</emphasis>'ed or
over-written!
</para>
</refsect1>
<refsect1 id="pam_get_authtok-options">
<title>OPTIONS</title>
<para>
<function>pam_get_authtok</function> honours the following module
options:
</para>
<variablelist>
<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>use_authtok</option>
</term>
<listitem>
<para>
When password changing enforce the module to set the new
token to the one provided by a previously stacked
<option>password</option> module. If no token is available
token changing will fail.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>authtok_type=<replaceable>XXX</replaceable></option>
</term>
<listitem>
<para>
The default action is for the module to use the
following prompts when requesting passwords:
"New UNIX password: " and "Retype UNIX password: ".
The example word <emphasis>UNIX</emphasis> can
be replaced with this option, by default it is empty.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id="pam_get_authtok-return_values">
<title>RETURN VALUES</title>
<variablelist>
<varlistentry>
<term>PAM_AUTH_ERR</term>
<listitem>
<para>
Authentication token could not be retrieved.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_AUTHTOK_ERR</term>
<listitem>
<para>
New authentication could not be retrieved.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_SUCCESS</term>
<listitem>
<para>
Authentication token was successfully retrieved.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_SYSTEM_ERR</term>
<listitem>
<para>
No space for an authentication token was provided.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_TRY_AGAIN</term>
<listitem>
<para>
New authentication tokens mismatch.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='pam_get_authtok-see_also'>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>
</para>
</refsect1>
<refsect1 id='pam_get_authtok-standards'>
<title>STANDARDS</title>
<para>
The <function>pam_get_authtok</function> function is a Linux-PAM
extensions.
</para>
</refsect1>
</refentry>
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