path: root/modules/pam_tally2/pam_tally2.8.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
	"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd">

<refentry id="pam_tally2">

  <refmeta>
    <refentrytitle>pam_tally2</refentrytitle>
    <manvolnum>8</manvolnum>
    <refmiscinfo class="sectdesc">Linux-PAM Manual</refmiscinfo>
  </refmeta>

  <refnamediv id="pam_tally2-name">
    <refname>pam_tally2</refname>
    <refpurpose>The login counter (tallying) module</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis id="pam_tally2-cmdsynopsis1">
      <command>pam_tally2.so</command>
      <arg choice="opt">
	file=<replaceable>/path/to/counter</replaceable>
      </arg>
      <arg choice="opt">
        onerr=[<replaceable>fail</replaceable>|<replaceable>succeed</replaceable>]
      </arg>
      <arg choice="opt">
        magic_root
      </arg>
      <arg choice="opt">
        even_deny_root
      </arg>
      <arg choice="opt">
        deny=<replaceable>n</replaceable>
      </arg>
      <arg choice="opt">
        lock_time=<replaceable>n</replaceable>
      </arg>
      <arg choice="opt">
        unlock_time=<replaceable>n</replaceable>
      </arg>
      <arg choice="opt">
        root_unlock_time=<replaceable>n</replaceable>
      </arg>
      <arg choice="opt">
        serialize
      </arg>
      <arg choice="opt">
        audit
      </arg>
      <arg choice="opt">
        silent
      </arg>
      <arg choice="opt">
        no_log_info
      </arg>
      <arg choice="opt">
        debug
      </arg>
    </cmdsynopsis>
    <cmdsynopsis id="pam_tally2-cmdsynopsis2">
      <command>pam_tally2</command>
      <arg choice="opt">
	--file <replaceable>/path/to/counter</replaceable>
      </arg>
      <arg choice="opt">
	--user <replaceable>username</replaceable>
      </arg>
      <arg choice="opt">
	--reset[=<replaceable>n</replaceable>]
      </arg>
      <arg choice="opt">
        --quiet
      </arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1 id="pam_tally2-description">

    <title>DESCRIPTION</title>

    <para>
      This module maintains a count of attempted accesses, can
      reset count on success, can deny access if too many attempts fail.
    </para>
    <para>
      pam_tally2 comes in two parts:
      <emphasis remap='B'>pam_tally2.so</emphasis> and
      <command>pam_tally2</command>. The former is the PAM module and
      the latter, a stand-alone program. <command>pam_tally2</command>
      is an (optional) application which can be used to interrogate and
      manipulate the counter file. It can display user counts, set
      individual counts, or clear all counts. Setting artificially high
      counts may be useful for blocking users without changing their
      passwords. For example, one might find it useful to clear all counts
      every midnight from a cron job.
    </para>
    <para>
      Normally, failed attempts to access <emphasis>root</emphasis> will
      <emphasis remap='B'>not</emphasis> cause the root account to become
      blocked, to prevent denial-of-service: if your users aren't given
      shell accounts and root may only login via <command>su</command> or
      at the machine console (not telnet/rsh, etc), this is safe.
    </para>
  </refsect1>

  <refsect1 id="pam_tally2-options">

    <title>OPTIONS</title>
    <variablelist>
      <varlistentry>
        <term>
          GLOBAL OPTIONS
        </term>
        <listitem>
          <para>
            This can be used for <emphasis>auth</emphasis> and
            <emphasis>account</emphasis> module types.
          </para>
          <variablelist>
            <varlistentry>
              <term>
                <option>onerr=[<replaceable>fail</replaceable>|<replaceable>succeed</replaceable>]</option>
              </term>
              <listitem>
                <para>
                  If something weird happens (like unable to open the file),
                  return with <errorcode>PAM_SUCCESS</errorcode> if
                  <option>onerr=<replaceable>succeed</replaceable></option>
                  is given, else with the corresponding PAM error code.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>file=<replaceable>/path/to/counter</replaceable></option>
              </term>
              <listitem>
                <para>
                  File where to keep counts. Default is
                  <filename>/var/log/tallylog</filename>.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>audit</option>
              </term>
              <listitem>
                <para>
                  Will log the user name into the system log if the user is not found.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>silent</option>
              </term>
              <listitem>
                <para>
                  Don't print informative messages. The messages printed without the <emphasis>silent</emphasis> option leak presence of accounts on the system because they are not printed for non-existing accounts.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>no_log_info</option>
              </term>
              <listitem>
                <para>
                  Don't log informative messages via <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>debug</option>
              </term>
              <listitem>
                <para>
                  Always log tally count when it is incremented as a debug level message to the system log.
                </para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>
          AUTH OPTIONS
        </term>
        <listitem>
          <para>
            Authentication phase first increments attempted login counter and
            checks if user should be denied access. If the user is authenticated
            and the login process continues on call to <citerefentry>
	      <refentrytitle>pam_setcred</refentrytitle><manvolnum>3</manvolnum>
            </citerefentry> it resets the attempts counter.
          </para>
          <variablelist>
            <varlistentry>
              <term>
                <option>deny=<replaceable>n</replaceable></option>
              </term>
              <listitem>
                <para>
                  Deny access if tally for this user exceeds
                  <replaceable>n</replaceable>.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>lock_time=<replaceable>n</replaceable></option>
              </term>
              <listitem>
                <para>
                  Always deny for <replaceable>n</replaceable> seconds
                  after failed attempt.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>unlock_time=<replaceable>n</replaceable></option>
              </term>
              <listitem>
                <para>
                  Allow access after <replaceable>n</replaceable> seconds
                  after failed attempt. If this option is used the user will
                  be locked out for the specified amount of time after he
                  exceeded his maximum allowed attempts. Otherwise the
                  account is locked until the lock is removed by a manual
                  intervention of the system administrator.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>magic_root</option>
              </term>
              <listitem>
                <para>
                  If the module is invoked by a user with uid=0 the
                  counter is not incremented. The sysadmin should use this
                  for user launched services, like <command>su</command>,
                  otherwise this argument should be omitted.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>even_deny_root</option>
              </term>
              <listitem>
                <para>
                  Root account can become unavailable.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>root_unlock_time=<replaceable>n</replaceable></option>
              </term>
              <listitem>
                <para>
                  This option implies <option>even_deny_root</option> option.
                  Allow access after <replaceable>n</replaceable> seconds
                  to root account after failed attempt. If this option is used
                  the root user will be locked out for the specified amount of
                  time after he exceeded his maximum allowed attempts.
                </para>
              </listitem>
            </varlistentry>
            <varlistentry>
              <term>
                <option>serialize</option>
              </term>
              <listitem>
                <para>
                  Serialize access to the tally file using locks. This option might
                  be used only for non-multithreaded services because it depends on
                  the fcntl locking of the tally file. Also it is a good idea to use
                  this option only in such configurations where the time between auth
                  phase and account or setcred phase is not dependent on the
                  authenticating client. Otherwise the authenticating client will be
                  able to prevent simultaneous authentications by the same user by
                  simply artificially prolonging the time the file record lock is held.
                </para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>


      <varlistentry>
        <term>
          ACCOUNT OPTIONS
        </term>
        <listitem>
          <para>
            Account phase resets attempts counter if the user is
            <emphasis remap='B'>not</emphasis> magic root.
            This phase can be used optionally for services which don't call
            <citerefentry>
	      <refentrytitle>pam_setcred</refentrytitle><manvolnum>3</manvolnum>
            </citerefentry> correctly or if the reset should be done regardless
            of the failure of the account phase of other modules.
          </para>
          <variablelist>
            <varlistentry>
              <term>
                <option>magic_root</option>
              </term>
              <listitem>
                <para>
                  If the module is invoked by a user with uid=0 the
                  counter is not changed. The sysadmin should use this
                  for user launched services, like <command>su</command>,
                  otherwise this argument should be omitted.
                </para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id="pam_tally2-types">
    <title>MODULE TYPES PROVIDED</title>
    <para>
      The <option>auth</option> and <option>account</option>
      module types are provided.
    </para>
  </refsect1>

  <refsect1 id='pam_tally2-return_values'>
    <title>RETURN VALUES</title>
    <variablelist>
      <varlistentry>
        <term>PAM_AUTH_ERR</term>
        <listitem>
          <para>
            A invalid option was given, the module was not able
            to retrieve the user name, no valid counter file
            was found, or too many failed logins.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_SUCCESS</term>
        <listitem>
          <para>
            Everything was successful.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_USER_UNKNOWN</term>
        <listitem>
          <para>
	    User not known.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='pam_tally2-notes'>
    <title>NOTES</title>
    <para>
      pam_tally2 is not compatible with the old pam_tally faillog file format.
      This is caused by requirement of compatibility of the tallylog file
      format between 32bit and 64bit architectures on multiarch systems.
    </para>
    <para>
      There is no setuid wrapper for access to the data file such as when the
      <emphasis remap='B'>pam_tally2.so</emphasis> module is called from
      xscreensaver. As this would make it impossible to share PAM configuration
      with such services the following workaround is used: If the data file
      cannot be opened because of insufficient permissions
      (<errorcode>EACCES</errorcode>) the module returns
      <errorcode>PAM_IGNORE</errorcode>.
    </para>
  </refsect1>

  <refsect1 id='pam_tally2-examples'>
    <title>EXAMPLES</title>
    <para>
      Add the following line to <filename>/etc/pam.d/login</filename> to
      lock the account after 4 failed logins. Root account will be locked
      as well. The accounts will be automatically unlocked after 20 minutes.
      The module does not have to be called in the account phase because the
      <command>login</command> calls <citerefentry>
	<refentrytitle>pam_setcred</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry> correctly.
    </para>
    <programlisting>
auth     required       pam_securetty.so
auth     required       pam_tally2.so deny=4 even_deny_root unlock_time=1200
auth     required       pam_env.so
auth     required       pam_unix.so
auth     required       pam_nologin.so
account  required       pam_unix.so
password required       pam_unix.so
session  required       pam_limits.so
session  required       pam_unix.so
session  required       pam_lastlog.so nowtmp
session  optional       pam_mail.so standard
    </programlisting>
  </refsect1>

  <refsect1 id="pam_tally2-files">
    <title>FILES</title>
    <variablelist>
      <varlistentry>
        <term><filename>/var/log/tallylog</filename></term>
        <listitem>
          <para>failure count logging file</para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='pam_tally2-see_also'>
    <title>SEE ALSO</title>
    <para>
      <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_tally2-author'>
    <title>AUTHOR</title>
      <para>
        pam_tally2 was written by Tim Baverstock and Tomas Mraz.
      </para>
  </refsect1>

</refentry>