source: postlfs/security/heimdal.xml@ 359e1043

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
   "http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;

  <!ENTITY heimdal-download-http "http://ftp.vc-graz.ac.at/mirror/crypto/kerberos/heimdal/heimdal-&heimdal-version;.tar.gz">
  <!ENTITY heimdal-download-ftp  "ftp://ftp.pdc.kth.se/pub/heimdal/src/heimdal-&heimdal-version;.tar.gz">
  <!ENTITY heimdal-size          "3.2 MB">
  <!ENTITY heimdal-buildsize     "142 MB">
  <!ENTITY heimdal-time          "2.55 SBU">
]>

<sect1 id="heimdal" xreflabel="Heimdal-&heimdal-version;">
<?dbhtml filename="heimdal.html"?>
<title>Heimdal-&heimdal-version;</title>

<sect2>
<title>Introduction to <application>Heimdal</application></title>

<para><application>Heimdal</application> is a free implementation of Kerberos
5, that aims to be compatible with <acronym>MIT</acronym> krb5 and is backwards
compatible with krb4. Kerberos is a network authentication protocol. Basically
it preserves the integrity of passwords in any untrusted network (like the
Internet). Kerberized applications work hand-in-hand with sites that support
Kerberos to ensure that passwords cannot be stolen. A Kerberos installation
will make changes to the authentication mechanisms on your network and will
overwrite several programs and daemons from the 
<application>Coreutils</application>, <application>Inetutils</application>, 
<application>Qpopper</application> and <application>Shadow</application> 
packages.</para>

<sect3><title>Package information</title>
<itemizedlist spacing='compact'>
<listitem><para>Download (HTTP): <ulink url="&heimdal-download-http;"/></para></listitem>
<listitem><para>Download (FTP): <ulink url="&heimdal-download-ftp;"/></para></listitem>
<listitem><para>Download size: &heimdal-size;</para></listitem>
<listitem><para>Estimated Disk space required: &heimdal-buildsize;</para></listitem>
<listitem><para>Estimated build time: &heimdal-time;</para></listitem></itemizedlist>
</sect3>

<sect3><title>Additional downloads</title>
<itemizedlist spacing='compact'>
<listitem><para>Required Patch: <ulink
url="&patch-root;/heimdal-&heimdal-version;-fhs_compliance-1.patch"/></para>
</listitem>
<listitem><para>Required patch for cracklib: <ulink
url="&patch-root;/heimdal-&heimdal-version;-cracklib-1.patch"/></para>
</listitem>
</itemizedlist>

</sect3>

<sect3><title><application>Heimdal</application> dependencies</title>
<sect4><title>Required</title>
<para>
<xref linkend="openssl"/> and
<xref linkend="db"/>
</para></sect4>
<sect4><title>Optional</title>
<para>
<xref linkend="readline"/>,
<xref linkend="Linux_PAM"/>,
<xref linkend="openldap"/>,
X (<xref linkend="xorg"/> or <xref linkend="xfree86"/>),
<xref linkend="cracklib"/> and
<ulink url="http://www.pdc.kth.se/kth-krb/">krb4</ulink>
</para>

<note><para>
Some sort of time synchronization facility on your system (like <xref
linkend="ntp"/>) is required since Kerberos won't authenticate if the
time differential between a kerberized client and the
<acronym>KDC</acronym> server is more than 5 minutes.</para></note> 
</sect4>

</sect3>

</sect2>

<sect2>
<title>Installation of <application>Heimdal</application></title>

<para>
Before installing the package, you may want to preserve the
<command>ftp</command> program from the <application>Inetutils</application> 
package. This is because using the <application>Heimdal</application> 
<command>ftp</command> program to connect to non-kerberized ftp servers may 
not work properly. It will allow you to connect (letting you know that 
transmission of the password is clear text) but will have problems doing puts 
and gets.
</para>

<screen><userinput><command>mv /usr/bin/ftp /usr/bin/ftpn</command></userinput></screen>

<para>
If you wish the <application>Heimdal</application> package to link against the 
<application>cracklib</application> library, you must apply a patch:
</para>

<screen><userinput><command>patch -Np1 -i ../heimdal-&heimdal-version;-cracklib-1.patch</command></userinput></screen>

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

<screen><userinput><command>patch -Np1 -i ../heimdal-&heimdal-version;-fhs_compliance-1.patch &amp;&amp;
./configure --prefix=/usr --sysconfdir=/etc/heimdal \
    --datadir=/var/lib/heimdal --libexecdir=/usr/sbin \
    --sharedstatedir=/usr/share --localstatedir=/var/lib/heimdal \
    --enable-shared --with-openssl=/usr &amp;&amp;
make &amp;&amp;
make install &amp;&amp;
mv /bin/login /bin/login.shadow &amp;&amp;
mv /bin/su /bin/su.coreutils &amp;&amp;
mv /usr/bin/{login,su} /bin &amp;&amp;
ln -sf ../../bin/login /usr/bin &amp;&amp;
mv /usr/lib/lib{otp.so.0,otp.so.0.1.4,kafs.so.0,kafs.so.0.4.0} /lib &amp;&amp;
mv /usr/lib/lib{krb5.so.17,krb5.so.17.3.0,asn1.so.6,asn1.so.6.0.2} /lib &amp;&amp;
mv /usr/lib/lib{roken.so.16,roken.so.16.0.3,crypto.so.0.9.7} /lib &amp;&amp;
mv /usr/lib/lib{com_err.so.2,com_err.so.2.1,db-4.1.so} /lib &amp;&amp;
ln -sf ../../lib/lib{otp.so.0,otp.so.0.1.4,kafs.so.0,kafs.so.0.4.0} /usr/lib &amp;&amp;
ln -sf ../../lib/lib{krb5.so.17,krb5.so.17.3.0,asn1.so.6,asn1.so.6.0.2} /usr/lib &amp;&amp;
ln -sf ../../lib/lib{roken.so.16,roken.so.16.0.3,crypto.so.0.9.7} /usr/lib &amp;&amp;
ln -sf ../../lib/lib{com_err.so.2,com_err.so.2.1,db-4.1.so} /usr/lib &amp;&amp;
ldconfig</command></userinput></screen>

</sect2>

<sect2>
<title>Command explanations</title>

<para><parameter>--libexecdir=/usr/sbin</parameter>: This switch puts the 
daemon programs into <filename class="directory">/usr/sbin</filename>.
</para>

<note><para>
If you want to preserve all your existing <application>Inetutils</application> 
package daemons, install the <application>Heimdal</application> daemons into 
<filename class="directory">/usr/sbin/heimdal</filename> (or wherever you want).
Since these programs will be called from <command>(x)inetd</command> or
<filename>rc</filename> scripts, it really doesn't matter where they are 
installed, as long as they are correctly specified in the
<filename>/etc/(x)inetd.conf</filename> file and <filename>rc</filename>
scripts. If you choose something other than 
<filename class="directory">/usr/sbin</filename>, you may want to move some of 
the user programs (such as <command>kadmin</command>) to 
<filename class="directory">/usr/sbin</filename> manually so they'll be in the
privileged user's default path.</para></note>

<para>
<screen><command>mv /bin/login /bin/login.shadow
mv /bin/su /bin/su.coreutils
mv /usr/bin/{login,su} /bin
ln -sf ../../bin/login /usr/bin</command></screen>

The <command>login</command> and <command>su</command> programs installed by 
<application>Heimdal</application> belong in the 
<filename class="directory">/bin</filename> directory. The
<command>login</command> program is symlinked because 
<application>Heimdal</application> is expecting to find it in 
<filename class="directory">/usr/bin</filename>. The old executables are 
preserved before the move to keep things sane should breaks occur.
</para>

<para>
<screen><command>mv /usr/lib/lib{otp.so.0,otp.so.0.1.4,kafs.so.0,kafs.so.0.4.0} /lib
mv /usr/lib/lib{krb5.so.17,krb5.so.17.3.0,asn1.so.6,asn1.so.6.0.2} /lib
mv /usr/lib/lib{roken.so.16,roken.so.16.0.3,crypto.so.0.9.7} /lib
mv /usr/lib/lib{com_err.so.2,com_err.so.2.1,db-4.1.so} /lib
ln -sf ../../lib/lib{otp.so.0,otp.so.0.1.4,kafs.so.0,kafs.so.0.4.0} /usr/lib
ln -sf ../../lib/lib{krb5.so.17,krb5.so.17.3.0,asn1.so.6,asn1.so.6.0.2} /usr/lib
ln -sf ../../lib/lib{roken.so.16,roken.so.16.0.3,crypto.so.0.9.7} /usr/lib
ln -sf ../../lib/lib{com_err.so.2,com_err.so.2.1,db-4.1.so} /usr/lib</command></screen>

The <command>login</command> and <command>su</command> programs
installed by <application>Heimdal</application> link against 
<application>Heimdal</application> libraries as well as libraries provided by 
the <application>OpenSSL</application>, <application>Berkeley DB</application> 
and <application>E2fsprogs</application> packages. These libraries are moved 
to <filename class="directory">/lib</filename> to be <acronym>FHS</acronym>
compliant and also in case <filename class="directory">/usr</filename> is 
located on a separate partition which may not always be mounted.
</para>

</sect2>

<sect2>
<title>Configuring <application>Heimdal</application></title>

<sect3><title>Config files</title>
<para><filename>/etc/heimdal/*</filename></para>
</sect3>

<sect3><title>Configuration Information</title>

<sect4><title>Master <acronym>KDC</acronym> Server Configuration</title>

<para>
Create the Kerberos configuration file with the following commands:
</para>

<screen><userinput><command>install -d /etc/heimdal &amp;&amp;
cat &gt; /etc/heimdal/krb5.conf &lt;&lt; "EOF"</command>
# Begin /etc/heimdal/krb5.conf

[libdefaults]
    default_realm = <replaceable>[EXAMPLE.COM]</replaceable>
    encrypt = true

[realms]
    <replaceable>[EXAMPLE.COM]</replaceable> = {
        kdc = <replaceable>[hostname.example.com]</replaceable>
        admin_server = <replaceable>[hostname.example.com]</replaceable>
        kpasswd_server = <replaceable>[hostname.example.com]</replaceable>
    }

[domain_realm]
    .<replaceable>[example.com]</replaceable> = <replaceable>[EXAMPLE.COM]</replaceable>

[logging]
    kdc = FILE:/var/log/kdc.log
    admin_server = FILE:/var/log/kadmin.log
    default = FILE:/var/log/krb.log

# End /etc/heimdal/krb5.conf
<command>EOF</command></userinput></screen>

<para>
You will need to substitute your domain and proper hostname for the 
occurrences of the <replaceable>[hostname]</replaceable> and 
<replaceable>[EXAMPLE.COM]</replaceable> names.
</para>

<para>
<userinput>default_realm</userinput> should be the name of your domain changed 
to ALL CAPS. This isn't required, but both <application>Heimdal</application> 
and <application><acronym>MIT</acronym> krb5</application> recommend it.
</para>

<para>
<userinput>encrypt = true</userinput> provides encryption of all traffic 
between kerberized clients and servers. It's not necessary and can be left 
off. If you leave it off, you can encrypt all traffic from the client to the 
server using a switch on the client program instead.
</para>

<para>
The <userinput>[realms]</userinput> parameters tell the client programs where 
to look for the <acronym>KDC</acronym> authentication services.
</para>

<para>
The <userinput>[domain_realm]</userinput> section maps a domain to a realm.
</para>

<para>
Store the master password in a key file using the following commands:
</para>

<screen><userinput><command>install -d -m 755 /var/lib/heimdal &amp;&amp;
kstash</command></userinput></screen>

<para>
Create the <acronym>KDC</acronym> database:
</para>

<screen><userinput><command>kadmin -l</command></userinput></screen>

<para>
Choose the defaults for now. You can go in later and change the
defaults, should you feel the need. At the
<userinput>kadmin&gt;</userinput> prompt, issue the following statement:
</para>

<screen><userinput><command>init <replaceable>[EXAMPLE.COM]</replaceable></command></userinput></screen>

<para>
The database must now be populated with at least one principle (user). For now, 
just use your regular login name or root. You may create as few, or as many
principles as you wish using the following statement: 
</para>

<screen><userinput><command>add <replaceable>[loginname]</replaceable></command></userinput></screen>

<para>
The <acronym>KDC</acronym> server and any machine running kerberized
server daemons must have a host key installed:
</para>

<screen><userinput><command>add --random-key host/<replaceable>[hostname.example.com]</replaceable></command></userinput></screen>

<para>
After choosing the defaults when prompted, you will have to export the
data to a keytab file:
</para>

<screen><userinput><command>ext host/<replaceable>[hostname.example.com]</replaceable></command></userinput></screen>

<para>
This should have created two files in
<filename class="directory">/etc/heimdal</filename>:
<filename>krb5.keytab</filename> (Kerberos 5) and
<filename>srvtab</filename> (Kerberos 4). Both files should have 600
(root rw only) permissions. Keeping the keytab files from public access
is crucial to the overall security of the Kerberos installation.
</para>

<para>
Eventually, you'll want to add server daemon principles to the database
and extract them to the keytab file. You do this in the same way you
created the host principles. Below is an example:
</para>

<screen><userinput><command>add --random-key ftp/<replaceable>[hostname.example.com]</replaceable></command></userinput></screen>

<para>
(choose the defaults)
</para>

<screen><userinput><command>ext ftp/<replaceable>[hostname.example.com]</replaceable></command></userinput></screen>

<para>
Exit the <command>kadmin</command> program (use <command>quit</command>
or <command>exit</command>) and return back to the shell prompt. Start
the <acronym>KDC</acronym> daemon manually, just to test out the 
installation:
</para>

<screen><userinput><command>/usr/sbin/kdc &amp;</command></userinput></screen>

<para>
Attempt to get a <acronym>TGT</acronym> (ticket granting ticket) with the 
following command:
</para>

<screen><userinput><command>kinit <replaceable>[loginname]</replaceable></command></userinput></screen>

<para>
You will be prompted for the password you created. After you get your
ticket, you should list it with the following command:
</para>

<screen><userinput><command>klist</command></userinput></screen>

<para>
Information about the ticket should be displayed on the screen.
</para>

<para>
To test the functionality of the keytab file, issue the following command:
</para>

<screen><userinput><command>ktutil list</command></userinput></screen>

<para>
This should dump a list of the host principals, along with the encryption
methods used to access the principals.
</para>

<para>
At this point, if everything has been successful so far, you can feel
fairly confident in the installation and configuration of the package.
</para>

<para>Install the <filename>/etc/rc.d/init.d/heimdal</filename> init script
included in the <xref linkend="intro-important-bootscripts"/>
package:</para>

<screen><userinput><command>make install-heimdal</command></userinput></screen>

</sect4>

<sect4><title>Using Kerberized Client Programs</title>

<para>
To use the kerberized client programs (<command>telnet</command>,
<command>ftp</command>, <command>rsh</command>,
<command>rxterm</command>, <command>rxtelnet</command>,
<command>rcp</command>, <command>xnlock</command>), you first must get
a <acronym>TGT</acronym>. Use the <command>kinit</command> program to
get the ticket. After you've acquired the ticket, you can use the
kerberized programs to connect to any kerberized server on the network.
You will not be prompted for authentication until your ticket expires
(default is one day), unless you specify a different user as a command
line argument to the program.
</para>

<para>
The kerberized programs will connect to non-kerberized daemons, warning
you that authentication is not encrypted. As mentioned earlier, only the
<command>ftp</command> program gives any trouble connecting to 
non-kerberized daemons.
</para>

<para>In order to use the <application>Heimdal</application> 
<application>X</application> programs, you'll need to add a service port
entry to the <filename>/etc/services</filename> file for the 
<command>kxd</command> server. There is no 'standardized port number' for
the 'kx' service in the IANA database, so you'll have to pick an unused port 
number. Add an entry to the <filename>services</filename> file similar to the 
entry below (substitute your chosen port number for 
<replaceable>[49150]</replaceable>):</para>

<screen><userinput>kx              <replaceable>[49150]</replaceable>/tcp   # Heimdal kerberos X
kx              <replaceable>[49150]</replaceable>/udp   # Heimdal kerberos X</userinput></screen>

<para>
For additional information consult <ulink
url="http://www.linuxfromscratch.org/hints/downloads/files/heimdal.txt">the
Heimdal hint</ulink> on which the above instructions are based.
</para>

</sect4>

</sect3>

</sect2>

<sect2>
<title>Contents</title>

<para>The <application>Heimdal</application> package contains
<command>afslog</command>,
<command>dump_log</command>,
<command>ftp</command>,
<command>ftpd</command>,
<command>hprop</command>,
<command>hpropd</command>,
<command>ipropd-master</command>,
<command>ipropd-slave</command>,
<command>kadmin</command>,
<command>kadmind</command>,
<command>kauth</command>,
<command>kdc</command>,
<command>kdestroy</command>,
<command>kf</command>,
<command>kfd</command>,
<command>kgetcred</command>,
<command>kinit</command>,
<command>klist</command>,
<command>kpasswd</command>,
<command>kpasswdd</command>,
<command>krb5-config</command>,
<command>kstash</command>,
<command>ktutil</command>,
<command>kx</command>,
<command>kxd</command>,
<command>login</command>,
<command>mk_cmds</command>,
<command>otp</command>,
<command>otpprint</command>,
<command>pagsh</command>,
<command>pfrom</command>,
<command>popper</command>,
<command>push</command>,
<command>rcp</command>,
<command>replay_log</command>,
<command>rsh</command>,
<command>rshd</command>,
<command>rxtelnet</command>,
<command>rxterm</command>,
<command>string2key</command>,
<command>su</command>,
<command>telnet</command>,
<command>telnetd</command>,
<command>tenletxr</command>,
<command>truncate_log</command>,
<command>verify_krb5_conf</command>,
<command>xnlock</command>,
<filename class="libraryfile">libasn1</filename>,
<filename class="libraryfile">libeditline</filename>,
<filename class="libraryfile">libgssapi</filename>,
<filename class="libraryfile">libhdb</filename>,
<filename class="libraryfile">libkadm5clnt</filename>,
<filename class="libraryfile">libkadm5srv</filename>,
<filename class="libraryfile">libkafs</filename>,
<filename class="libraryfile">libkrb5</filename>,
<filename class="libraryfile">libotp</filename>,
<filename class="libraryfile">libroken</filename>,
<filename class="libraryfile">libsl</filename> and
<filename class="libraryfile">libss</filename>.
</para>

</sect2>

<sect2><title>Description</title>

<sect3><title>afslog</title>
<para><command>afslog</command> obtains <acronym>AFS</acronym> tokens for a 
number of cells.</para></sect3>

<sect3><title>hprop</title>
<para><command>hprop</command> takes a principal database in a specified
format and converts it into a stream of <application>Heimdal</application> 
database records.</para></sect3>

<sect3><title>hpropd</title>
<para><command>hpropd</command> receives a database sent by
<command>hprop</command> and writes it as a local database.</para></sect3>

<sect3><title>kadmin</title>
<para><command>kadmin</command> is a utility used to make modifications
to the Kerberos database.</para></sect3>

<sect3><title>kadmind</title>
<para><command>kadmind</command> is a server for administrative access
to the Kerberos database.</para></sect3>

<sect3><title>kauth, kinit</title>
<para><command>kauth</command> and <command>kinit</command> are used to
authenticate to the Kerberos server as a principal and acquire a ticket
granting ticket that can later be used to obtain tickets for other
services.</para></sect3>

<sect3><title>kdc</title>
<para><command>kdc</command> is a Kerberos 5 server.</para></sect3>

<sect3><title>kdestroy</title>
<para><command>kdestroy</command> removes a principle's current set of
tickets.</para></sect3>

<sect3><title>kf</title>
<para><command>kf</command> is a program which forwards tickets to a
remote host through an authenticated and encrypted
stream.</para></sect3>

<sect3><title>kfd</title>
<para><command>kfd</command> receives forwarded tickets.</para></sect3>

<sect3><title>kgetcred</title>
<para><command>kgetcred</command> obtains a ticket for a
service.</para></sect3>

<sect3><title>klist</title>
<para><command>klist</command> reads and displays the current tickets in
the credential cache.</para></sect3>

<sect3><title>kpasswd</title>
<para><command>kpasswd</command> is a program for changing Kerberos 5
passwords.</para></sect3>

<sect3><title>kpasswdd</title>
<para><command>kpasswdd</command> is a Kerberos 5 password changing
server.</para></sect3>

<sect3><title>krb5-config</title>
<para><command>krb5-config</command> gives information on how to link
programs against <application>Heimdal</application> libraries.</para></sect3>

<sect3><title>kstash</title>
<para><command>kstash</command> stores the <acronym>KDC</acronym> master
password in a file.</para></sect3>

<sect3><title>ktutil</title>
<para><command>ktutil</command> is a program for managing Kerberos
keytabs.</para></sect3>

<sect3><title>kx</title>
<para><command>kx</command> is a program which securely forwards 
<application>X</application> connections.</para></sect3>

<sect3><title>kxd</title>
<para><command>kxd</command> is the daemon for
<command>kx</command>.</para></sect3>

<sect3><title>otp</title>
<para><command>otp</command> manages one-time passwords.</para></sect3>

<sect3><title>otpprint</title>
<para><command>otpprint</command> prints lists of one-time
passwords.</para></sect3>

<sect3><title>rxtelnet</title>
<para><command>rxtelnet</command> starts an <command>xterm</command> 
window with a telnet to a given host and forwards
<application>X</application> connections.</para></sect3>

<sect3><title>rxterm</title>
<para><command>rxterm</command> starts a secure remote
<command>xterm</command>.</para></sect3>

<sect3><title>string2key</title>
<para><command>string2key</command> maps a password into a
key.</para></sect3>

<sect3><title>tenletxr</title>
<para><command>tenletxr</command> forwards <application>X</application> 
connections backwards.</para></sect3>

<sect3><title>verify_krb5_conf</title>
<para><command>verify_krb5_conf</command> checks
<filename>krb5.conf</filename> file for obvious errors.</para></sect3>

<sect3><title>xnlock</title>
<para><command>xnlock</command> is a program that acts as a secure screen
saver for workstations running <application>X</application>.</para></sect3>

</sect2>

</sect1>