source: postlfs/security/heimdal.xml@ b4b71892

<?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 Coreutils, Inetutils, Qpopper
and Shadow 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 Inetutils package. This is
because using the Heimdal <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 Heimdal package to link against the cracklib 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 Inetutils package daemons,
install the Heimdal 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
<command>rc</command> scripts, it really doesn't matter where they live,
as long as they are correctly specified in the
<filename>/etc/(x)inetd.conf</filename> file and <command>rc</command>
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.
</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 Heimdal belong in the <filename
class="directory">/bin</filename> directory. The
<command>login</command> program is symlinked because Heimdal is expecting
to find it in <filename class="directory">/usr/bin</filename>. We
preserve the old executables 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 Heimdal link against Heimdal libraries as well as crypto
and db libraries. We move these libraries to <filename
class="directory">/lib</filename> to be <acronym>FHS</acronym>
compliant and in case when <filename
class="directory">/usr</filename> is located on a separate partition which
may not always be mounted.
</para>

</sect2>

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

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

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

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

<para>
Create the Kerberos configuration file with the following command:
</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>[LFS.ORG]</replaceable>
    encrypt = true

[realms]
    <replaceable>[LFS.ORG]</replaceable> = {
        kdc = <replaceable>[belgarath.lfs.org]</replaceable>
        admin_server = <replaceable>[belgarath.lfs.org]</replaceable>
        kpasswd_server = <replaceable>[belgarath.lfs.org]</replaceable>
    }

[domain_realm]
    .<replaceable>[lfs.org]</replaceable> = <replaceable>[LFS.ORG]</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
occurances of the belgarath and lfs.org names.
</para>

<para>
<userinput>default_realm</userinput> should be the name of your domain changed to ALL CAPS.
This isn't required, but both Heimdal and <acronym>MIT</acronym>
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>[LFS.ORG]</replaceable></command></userinput></screen>

<para>
Now we need to populate the database with principles (users). For now,
just use your regular login name or root. 
</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>[belgarath.lfs.org]</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>[belgarath.lfs.org]</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>[belgarath.lfs.org]</replaceable></command></userinput></screen>

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

<screen><userinput><command>ext ftp/<replaceable>[belgarath.lfs.org]</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>
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 AFS 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 Heimdal 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 an 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 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 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 the 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 Heimdal 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 X
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> program starts an
<command>xterm</command> window with a telnet to given host and forwards
X 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 X 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 X.</para></sect3>

</sect2>

</sect1>