source: postlfs/security/libcap.xml@ bc0d10e

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

  <!ENTITY libcap-download-http "&kernel-dl;/linux/libs/security/linux-privs/libcap2/libcap-&libcap-version;.tar.xz">
  <!ENTITY libcap-download-ftp  " ">
  <!ENTITY libcap-md5sum        "52120c05dc797b01f5a7ae70f4335e96">
  <!ENTITY libcap-size          "97 KB">
  <!ENTITY libcap-buildsize     "1 MB">
  <!ENTITY libcap-time          "less than 0.1 SBU">
]>

<sect1 id="libcap-pam" xreflabel="libcap-&libcap-version; with PAM">
  <?dbhtml filename="libcap.html"?>

  <sect1info>
    <othername>$LastChangedBy$</othername>
    <date>$Date$</date>
  </sect1info>

  <title>libcap-&libcap-version; with PAM</title>

  <indexterm zone="libcap-pam">
    <primary sortas="a-libcap-pam">libcap</primary>
  </indexterm>

  <sect2 role="package">
    <title>Introduction to libcap with PAM</title>

    <para>The <application>libcap</application> package was installed in 
    LFS, but if <application>Linux-PAM</application> support is desired,
    the PAM module must be built (after installation of
    <application>Linux-PAM</application>).</para>

    &lfs90_checked;

    <bridgehead renderas="sect3">Package Information</bridgehead>
    <itemizedlist spacing="compact">
      <listitem>
        <para>Download (HTTP): <ulink url="&libcap-download-http;"/></para>
      </listitem>
      <listitem>
        <para>Download (FTP): <ulink url="&libcap-download-ftp;"/></para>
      </listitem>
      <listitem>
        <para>Download MD5 sum: &libcap-md5sum;</para>
      </listitem>
      <listitem>
        <para>Download size: &libcap-size;</para>
      </listitem>
      <listitem>
        <para>Estimated disk space required: &libcap-buildsize;</para>
      </listitem>
      <listitem>
        <para>Estimated build time: &libcap-time;</para>
      </listitem>
    </itemizedlist>

    <bridgehead renderas="sect3">libcap Dependencies</bridgehead>

    <bridgehead renderas="sect4">Required</bridgehead>
    <para role="required">
      <xref linkend="linux-pam"/>
    </para>

    <para condition="html" role="usernotes">User Notes:
    <ulink url="&blfs-wiki;/libcap"/></para>

  </sect2>

  <sect2 role="installation">
    <title>Installation of libcap</title>

    <note>
      <para>If you are upgrading libcap from a previous version, use the
      instructions in 
      <ulink url="../../../../lfs/view/development/chapter06/libcap.html">LFS libcap page</ulink>
      to upgrade libcap. If the PAM module has been built, it will automatically
      be picked up.</para>
    </note>

    <para>Install <application>libcap</application> by running the following
    commands:</para>

<screen><userinput>make -C pam_cap</userinput></screen>

    <para>This package does not come with a test suite.</para>

    <para>Now, as the <systemitem class="username">root</systemitem> user:</para>

<screen role="root"><userinput>install -v -m755 pam_cap/pam_cap.so /lib/security &amp;&amp;
install -v -m644 pam_cap/capability.conf /etc/security</userinput></screen>

  </sect2>

  <sect2 role="configuration">
    <title>Configuring Libcap</title>

    <para>In order to allow <application>Linux-PAM</application> to grant
    privileges based on POSIX capabilites, you need to add the libcap module
    to the begining of the <filename>/etc/pam.d/system-auth</filename> file.
    Make the required edits with the following commands:</para>

<screen role="root"><userinput>mv -v /etc/pam.d/system-auth{,.bak} &amp;&amp;
cat &gt; /etc/pam.d/system-auth &lt;&lt; "EOF" &amp;&amp;
<literal># Begin /etc/pam.d/system-auth

auth      optional    pam_cap.so</literal>
EOF
tail -n +3 /etc/pam.d/system-auth.bak &gt;&gt; /etc/pam.d/system-auth</userinput></screen>

    <para>Additonally, you'll need to modify the
    <filename>/etc/security/capability.conf</filename> file to grant necessary
    privileges to users, and utilize the <command>setcap</command>
    utility to set capabilities on specific utilities as needed. See
    <command>man 8 setcap</command> and <command>man 3 cap_from_text</command>
    for additional information.</para>
 
  </sect2>

  <sect2 role="content">
    <title>Contents</title>

    <segmentedlist>
      <segtitle>Installed Programs</segtitle>
      <segtitle>Installed Library</segtitle>
      <segtitle>Installed Directories</segtitle>

      <seglistitem>
        <seg>None</seg>
        <seg>pam_cap.so</seg>
        <seg>None</seg>
      </seglistitem>
    </segmentedlist>

  </sect2>

</sect1>