source: postlfs/security/libcap.xml@ 41b674d

<?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 "https://www.kernel.org/pub/linux/libs/security/linux-privs/libcap2/libcap-&libcap-version;.tar.xz">
  <!ENTITY libcap-download-ftp  "ftp://ftp.kernel.org/pub/linux/libs/security/linux-privs/libcap2/libcap-&libcap-version;.tar.xz">
  <!ENTITY libcap-md5sum        "d43ab9f680435a7fff35b4ace8d45b80">
  <!ENTITY libcap-size          "62 KB">
  <!ENTITY libcap-buildsize     "1.5 MB">
  <!ENTITY libcap-time          "0.1 SBU">
]>

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

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

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

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

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

    <para>The <application>libcap</application> package implements the
    user-space interfaces to the POSIX 1003.1e capabilities available in Linux
    kernels. These capabilities are a partitioning of the all powerful root
    privilege into a set of distinct privileges.  </para>

    &lfs75_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="attr"/></para>

    <bridgehead renderas="sect4">Optional</bridgehead>
    <para role="optional"><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>

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

<screen><userinput>sed -i 's:LIBDIR:PAM_&amp;:g' pam_cap/Makefile &amp;&amp;
make</userinput></screen>

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

    <para>
      If you want to disable installing the static library, use this sed:
    </para>

<screen><userinput>sed -i '/install.*STALIBNAME/ s/^/#/' libcap/Makefile</userinput></screen>

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

<!-- dev note: make DESTDIR=<DESTDIR> prefix=/usr SBINDIR=<DESTDIR>/sbin PAM_LIBDIR=<DESTDIR>/lib RAISE_SETFCAP=no -->

<screen role="root"><userinput>make prefix=/usr \
     SBINDIR=/sbin \
     PAM_LIBDIR=/lib \
     RAISE_SETFCAP=no install</userinput></screen>

   <para>
     Still as the <systemitem class="username">root</systemitem> user, 
     clean up some library locations and permissions:
   </para>

<screen role="root"><userinput>chmod -v 755 /usr/lib/libcap.so &amp;&amp;
mv -v /usr/lib/libcap.so.* /lib &amp;&amp;
ln -sfv ../../lib/libcap.so.2 /usr/lib/libcap.so</userinput></screen>

  </sect2>

  <sect2 role="commands">
    <title>Command Explanations</title>

    <para>
      <command>sed -i '...'</command>, <parameter>PAM_LIBDIR=/lib</parameter>:
      These correct PAM module install location.
    </para>

    <para><parameter>RAISE_SETFCAP=no</parameter>: This parameter skips trying
    to use <application>setcap</application> on itself.  This avoids an installation
    error if the kernel or file system do not support extended capabilities.</para>

  </sect2>

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

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

      <seglistitem>
        <seg>capsh, getcap, getpcaps, and setcap</seg>
        <seg>libcap.{so,a}</seg>
        <seg>None</seg>
      </seglistitem>
    </segmentedlist>

    <variablelist>
      <bridgehead renderas="sect3">Short Descriptions</bridgehead>
      <?dbfo list-presentation="list"?>
      <?dbhtml list-presentation="table"?>

      <varlistentry id="capsh">
        <term><command>capsh</command></term>
        <listitem>
          <para>is a shell wrapper to explore and constrain capability support.</para>
          <indexterm zone="libcap capsh">
            <primary sortas="b-capsh">capsh</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="getcap">
        <term><command>getcap</command></term>
        <listitem>
          <para>examines file capabilities.</para>
          <indexterm zone="libcap getcap">
            <primary sortas="b-getcap">getcap</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="getpcaps">
        <term><command>getpcaps</command></term>
        <listitem>
          <para>displays the capabilities on the queried process(es).</para>
          <indexterm zone="libcap getpcaps">
            <primary sortas="b-getpcaps">getpcaps</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="setcap">
        <term><command>setcap</command></term>
        <listitem>
          <para>sets file file capabilities.</para>
          <indexterm zone="libcap setcap">
            <primary sortas="b-setcap">setcap</primary>
          </indexterm>
        </listitem>
      </varlistentry>

      <varlistentry id="libcap-lib">
        <term><filename class='libraryfile'>libcap.{so,a}</filename></term>
        <listitem>
          <para>contains the <application>libcap</application> API functions.</para>
          <indexterm zone="libcap libcap-lib">
            <primary sortas="c-libcap">libcap.{so,a}</primary>
          </indexterm>
        </listitem>
      </varlistentry>

    </variablelist>

  </sect2>

</sect1>