shadow/man/pwck.8.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
   SPDX-FileCopyrightText: 1992       , Julianne Frances Haugh
   SPDX-FileCopyrightText: 2007 - 2011, Nicolas François
   SPDX-License-Identifier: BSD-3-Clause
-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
<!ENTITY NONEXISTENT           SYSTEM "login.defs.d/NONEXISTENT.xml">
<!ENTITY PASS_MAX_DAYS         SYSTEM "login.defs.d/PASS_MAX_DAYS.xml">
<!ENTITY PASS_MIN_DAYS         SYSTEM "login.defs.d/PASS_MIN_DAYS.xml">
<!ENTITY PASS_WARN_AGE         SYSTEM "login.defs.d/PASS_WARN_AGE.xml">
<!ENTITY TCB_AUTH_GROUP        SYSTEM "login.defs.d/TCB_AUTH_GROUP.xml">
<!ENTITY TCB_SYMLINKS          SYSTEM "login.defs.d/TCB_SYMLINKS.xml">
<!ENTITY USE_TCB               SYSTEM "login.defs.d/USE_TCB.xml">
<!-- SHADOW-CONFIG-HERE -->
]>
<refentry id='pwck.8'>
  <!-- $Id$ -->
  <refentryinfo>
    <author>
      <firstname>Julianne Frances</firstname>
      <surname>Haugh</surname>
      <contrib>Creation, 1992</contrib>
    </author>
    <author>
      <firstname>Thomas</firstname>
      <surname>Kłoczko</surname>
      <email>kloczek@pld.org.pl</email>
      <contrib>shadow-utils maintainer, 2000 - 2007</contrib>
    </author>
    <author>
      <firstname>Nicolas</firstname>
      <surname>François</surname>
      <email>nicolas.francois@centraliens.net</email>
      <contrib>shadow-utils maintainer, 2007 - now</contrib>
    </author>
  </refentryinfo>
  <refmeta>
    <refentrytitle>pwck</refentrytitle>
    <manvolnum>8</manvolnum>
    <refmiscinfo class="sectdesc">System Management Commands</refmiscinfo>
    <refmiscinfo class="source">shadow-utils</refmiscinfo>
    <refmiscinfo class="version">&SHADOW_UTILS_VERSION;</refmiscinfo>
  </refmeta>
  <refnamediv id='name'>
    <refname>pwck</refname>
    <refpurpose>verify the integrity of password files</refpurpose>
  </refnamediv>
  <!-- body begins here -->
  <refsynopsisdiv id='synopsis'>
    <cmdsynopsis>
      <command>pwck</command>
      <arg choice='opt'>options</arg>
      <arg choice='opt'>
	<arg choice='plain'>
	  <replaceable>PASSWORDFILE</replaceable>
	</arg>
	<arg choice='opt'>
	  <arg choice='plain'>
	    <replaceable>SHADOWFILE</replaceable>
	  </arg>
	</arg>
      </arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      The <command>pwck</command> command verifies the integrity of the
      users and authentication information. It checks that all entries in
      <filename>/etc/passwd</filename> and <filename>/etc/shadow</filename>
      <phrase condition="tcb">(or the files in
      <filename>/etc/tcb</filename>, when <option>USE_TCB</option> is
      enabled)</phrase>
      have the proper format and contain valid data.
      The user is prompted to delete entries that are
      improperly formatted or which have other uncorrectable errors.
    </para>

    <para>Checks are made to verify that each entry has:</para>
    <itemizedlist mark='bullet'>
      <listitem>
	<para>the correct number of fields</para>
      </listitem>
      <listitem>
	<para>a unique and valid user name</para>
      </listitem>
      <listitem>
	<para>a valid user and group identifier</para>
      </listitem>
      <listitem>
	<para>a valid primary group</para>
      </listitem>
      <listitem>
	<para> a valid home directory</para>
      </listitem>
      <listitem>
	<para>a valid login shell</para>
      </listitem>
    </itemizedlist>

    <para>
      Checks for shadowed password information are enabled when the second
      file parameter <replaceable>SHADOWFILE</replaceable> is specified or
      when <filename>/etc/shadow</filename> exists on the system.
    </para>
    <para>
      These checks are the following:
    </para>
    <itemizedlist mark='bullet'>
      <listitem>
	<para>
	  every passwd entry has a matching shadow entry, and every shadow
	  entry has a matching passwd entry
	</para>
      </listitem>
      <listitem>
	<para>passwords are specified in the shadowed file</para>
      </listitem>
      <listitem>
	<para>shadow entries have the correct number of fields</para>
      </listitem>
      <listitem>
	<para>shadow entries are unique in shadow</para>
      </listitem>
      <listitem>
	<para>the last password changes are not in the future</para>
      </listitem>
    </itemizedlist>

    <para>
      The checks for correct number of fields and unique user name are
      fatal. If the entry has the wrong number of fields, the user will be
      prompted to delete the entire line. If the user does not answer
      affirmatively, all further checks are bypassed. An entry with a
      duplicated user name is prompted for deletion, but the remaining
      checks will still be made. All other errors are warnings and the user
      is encouraged to run the <command>usermod</command> command to correct
      the error.
    </para>

    <para>
      The commands which operate on the <filename>/etc/passwd</filename>
      file are not able to alter corrupted or duplicated entries.
      <command>pwck</command> should be used in those circumstances to
      remove the offending entry.
    </para>
  </refsect1>

  <refsect1 id='options'>
    <title>OPTIONS</title>
    <para>
      The <option>-r</option> and <option>-s</option> options cannot be
      combined.
    </para>
    <para>
      The options which apply to the <command>pwck</command> command are:
    </para>
    <variablelist remap='IP'>
      <varlistentry>
	<term>
	  <option>--badname</option>&nbsp;
	</term>
	<listitem>
	  <para>
        Allow names that do not conform to standards.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-h</option>, <option>--help</option></term>
	<listitem>
	  <para>Display help message and exit.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-q</option>, <option>--quiet</option></term>
	<listitem>
	  <para>
	    Report errors only. The warnings which do not require any
	    action from the user won't be displayed.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-r</option>, <option>--read-only</option></term>
	<listitem>
	  <para>
	    Execute the <command>pwck</command> command in read-only mode.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term>
	  <option>-R</option>, <option>--root</option>&nbsp;<replaceable>CHROOT_DIR</replaceable>
	</term>
	<listitem>
	  <para>
	    Apply changes in the <replaceable>CHROOT_DIR</replaceable>
	    directory and use the configuration files from the
	    <replaceable>CHROOT_DIR</replaceable> directory.
	    Only absolute paths are supported.
	  </para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><option>-s</option>, <option>--sort</option></term>
	<listitem>
	  <para>
	    Sort entries in <filename>/etc/passwd</filename> and
	    <filename>/etc/shadow</filename> by UID.
	  </para>
	  <para condition="tcb">
	    This option has no effect when <option>USE_TCB</option> is enabled.
	  </para>
	</listitem>
      </varlistentry>
    </variablelist>

    <para>
      By default, <command>pwck</command> operates on the files
      <filename>/etc/passwd</filename> and
      <filename>/etc/shadow</filename><phrase condition="tcb"> (or the
      files in <filename>/etc/tcb</filename>)</phrase>.
      The user may select alternate files with the
      <replaceable>passwd</replaceable> and
      <replaceable>shadow</replaceable> parameters.
    </para>
    <para condition="tcb">
      Note that when <option>USE_TCB</option> is enabled, you cannot
      specify an alternative <replaceable>shadow</replaceable> file. In
      future releases, this parameter could be replaced by an alternate
      TCB directory.
    </para>
  </refsect1>

  <refsect1 id='configuration'>
    <title>CONFIGURATION</title>
    <para>
      The following configuration variables in
      <filename>/etc/login.defs</filename> change the behavior of this
      tool:
    </para>
    <variablelist>
      &NONEXISTENT;
      &PASS_MAX_DAYS;
      &PASS_MIN_DAYS;
      &PASS_WARN_AGE;
      &TCB_AUTH_GROUP;
      &TCB_SYMLINKS;
      &USE_TCB;
    </variablelist>
  </refsect1>

  <refsect1 id='files'>
    <title>FILES</title>
    <variablelist>
      <varlistentry>
	<term><filename>/etc/group</filename></term>
	<listitem>
	  <para>Group account information.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><filename>/etc/passwd</filename></term>
	<listitem>
	  <para>User account information.</para>
	</listitem>
      </varlistentry>
      <varlistentry>
	<term><filename>/etc/shadow</filename></term>
	<listitem>
	  <para>Secure user account information.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='exit_values'>
    <title>EXIT VALUES</title>
    <para>
      The <command>pwck</command> command exits with the following values:
      <variablelist>
	<varlistentry>
	  <term><replaceable>0</replaceable></term>
	  <listitem>
	    <para>success</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>1</replaceable></term>
	  <listitem>
	    <para>invalid command syntax</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>2</replaceable></term>
	  <listitem>
	    <para>one or more bad password entries</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>3</replaceable></term>
	  <listitem>
	    <para>can't open password files</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>4</replaceable></term>
	  <listitem>
	    <para>can't lock password files</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>5</replaceable></term>
	  <listitem>
	    <para>can't update password files</para>
	  </listitem>
	</varlistentry>
	<varlistentry>
	  <term><replaceable>6</replaceable></term>
	  <listitem>
	    <para>can't sort password files</para>
	  </listitem>
	</varlistentry>
      </variablelist>
    </para>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>group</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>grpck</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>shadow</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>usermod</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>