path: root/share/FAQ/kerberos_setup.latex

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\begin{center}
{\LARGE {\bf Configuring Kerberos IV on 4.4 BSD}} \\
{\it Mark Dapoz} \\
{\it $<$md@bsc.no$>$} \\
{\it Bergen Scientific Centre} \\
{\it Bergen, Norway} \\
{\it April 4th, 1994} \\
\end{center}

\section{Introduction}

The following instructions can be used as a quick guide on how to set up
kerberos as distributed in 4.4 BSD.  However, you should refer to the
original Athena documentation for a complete description.


\section{Creating the initial database}

First make sure that you don't have any old kerberos databases around.  You
should change to the directory {\bf /etc/kerberosIV} and check that only the
following files are present:

\begin{verbatim}
mideon# cd /etc/kerberosIV
mideon# ls
README          krb.conf        krb.realms      register_keys
\end{verbatim}

If any additional files (such as principal.dir) exist, then use the
{\bf kdb\_destroy} command to destroy the old kerberos database.\\

You should now edit the {\bf krb.conf} and {\bf krb.realms} files to define
your kerberos realm.  In this case the realm will be {\it BSC.NO} and
the server is {\it mideon.bsc.no}.  We would edit the {\bf krb.conf}
file to be as follows:

\begin{verbatim}
mideon# cat krb.conf
BSC.NO
BSC.NO mideon.bsc.no admin server
CS.BERKELEY.EDU okeeffe.berkeley.edu
ATHENA.MIT.EDU kerberos.mit.edu
ATHENA.MIT.EDU kerberos-1.mit.edu
ATHENA.MIT.EDU kerberos-2.mit.edu
ATHENA.MIT.EDU kerberos-3.mit.edu
LCS.MIT.EDU kerberos.lcs.mit.edu
TELECOM.MIT.EDU bitsy.mit.edu
ARC.NASA.GOV trident.arc.nasa.gov
\end{verbatim}

Now we have to add mideon.bsc.no to the BSC.NO realm and also add an entry
to put all hosts in the .bsc.no domain in the BSC.NO realm.  The 
{\bf krb.realms} file would be updated as follows:

\begin{verbatim}
mideon# cat krb.realms
mideon.bsc.no   BSC.NO
.bsc.no         BSC.NO
.berkeley.edu   CS.BERKELEY.EDU
.MIT.EDU        ATHENA.MIT.EDU
.mit.edu        ATHENA.MIT.EDU
\end{verbatim}

Now we're ready to create the database, issue the {\bf kdb\_init} command
to do this:

\begin{verbatim}
mideon# kdb_init
Realm name [default  CS.BERKELEY.EDU ]: BSC.NO
You will be prompted for the database Master Password.
It is important that you NOT FORGET this password.

Enter Kerberos master key: 
\end{verbatim}

Now we have to save the key so that servers on the local machine can pick
it up.  Use the {\bf kstash} command to do this.

\begin{verbatim}
mideon# kstash

Enter Kerberos master key: 

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
\end{verbatim}

\section{Populating the database}

We now have to add some entries into the database.  First lets create an
entry for the user {\it md}.  Use the {\bf kdb\_edit} command to do this:

\begin{verbatim}
mideon# kdb_edit
Opening database...

Enter Kerberos master key: 

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
Previous or default values are in [brackets] ,
enter return to leave the same, or new value.

Principal name: md
Instance: 
md. not found, Create [y] ? 
Principal: md, Instance: , kdc_key_ver: 1
New Password: 
New Password: 

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ? 
Max ticket lifetime (*5 minutes) [ 255 ] ? 100
Attributes [ 0 ] ? 
Edit O.K.
\end{verbatim}

Now lets add an entry for the password changing daemon, kpasswd.  The
principal name must be {\it kpasswd} and the instance must be the name of
the local machine, {\it mideon} in this case.  Similarily, we must also add
an entry for the principal {\it rcmd} with an instance equal to the
hostname of the local machine.

\begin{verbatim}
Principal name: kpasswd
Instance: mideon
kpasswd.mideon not found, Create [y] ? 
Principal: kpasswd, Instance: mideon, kdc_key_ver: 1
New Password:                   <---- enter RANDOM here
New Password:                   <---- and here
Random password [y] ? 

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ? 
Max ticket lifetime (*5 minutes) [ 255 ] ? 
Attributes [ 0 ] ? 
Edit O.K.
Principal name: rcmd
Instance: mideon
rcmd.mideon not found, Create [y] ? 
Principal: rcmd, Instance: mideon, kdc_key_ver: 1
New Password:                   <---- enter RANDOM here
New Password:                   <---- and here
Random password [y] ? 

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ? 
Max ticket lifetime (*5 minutes) [ 255 ] ? 
Attributes [ 0 ] ? 
Edit O.K.
Principal name:                 <---- null entry here will cause an exit
\end{verbatim}

\section{Creating the server file}

We now have to extract all the instances which define the services on this
machine.  For this we use the {\bf ext\_srvtab} command.

\begin{verbatim}
mideon# ext_srvtab mideon

Enter Kerberos master key: 

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
Generating 'mideon-new-srvtab'....
\end{verbatim}

Now, this command only generates a temporary file which must be renamed
to {\bf srvtab} so that all the server can pick it up.  Use the mv command to
move it into place:

\begin{verbatim}
mideon# mv mideon-new-srvtab srvtab
\end{verbatim}

\section{Testing it all out}

First we have to start the kerberos daemon:

\begin{verbatim}
mideon# kerberos &
[1] 774
mideon# Kerberos server starting
        Sleep forever on error
        Log file is /var/log/kerberos.log
Current Kerberos master key version is 1.

Master key entered.  BEWARE!

Current Kerberos master key version is 1
Local realm: BSC.NO
\end{verbatim}

Now we can try using the {\bf kinit} command to get tokens for the id 
{\it md} that we created above:

\begin{verbatim}
mideon# kinit md
Kerberos Initialization for "md"
Kerberos Password: 
\end{verbatim}

Try listing the tokens using {\bf klist} to see if we really have them:

\begin{verbatim}
mideon# klist
Ticket file:    /tmp/tkt0
Principal:      md@BSC.NO

  Issued           Expires          Principal
Mar 23 21:06:52  Mar 24 05:06:52  krbtgt.BSC.NO@BSC.NO
\end{verbatim}

And now try changing the password using {\bf passwd} to check if the 
kpasswd daemon can get authorisation to the kerberos database:

\begin{verbatim}
mideon# passwd md
Changing Kerberos password for md.@BSC.NO.
Old Kerberos password:
New Kerberos password:
Retype new Kerberos password:
Update complete.
\end{verbatim}

\section{Adding su priviledges}

We should now add an id which is authorised to su to root.  This is
controlled by having an instance of {\it root} associated with a principal.
Using {\bf kdb\_edit} we can create the entry {\it md.root} in the kerberos
database:

\begin{verbatim}
mideon# kdb_edit
Opening database...

Enter Kerberos master key: 

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
Previous or default values are in [brackets] ,
enter return to leave the same, or new value.

Principal name: md
Instance: root
md.admin not found, Create [y] ? 
Principal: md, Instance: admin, kdc_key_ver: 1
New Password: 
New Password: 

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ? 
Max ticket lifetime (*5 minutes) [ 255 ] ? 12
Attributes [ 0 ] ? 
Edit O.K.
Principal name: 
\end{verbatim}

Now try getting tokens for it to make sure it works:

\begin{verbatim}
mideon# kinit md.root
Kerberos Initialization for "md.root"
Kerberos Password: 
\end{verbatim}

And list them to check expiry times:

\begin{verbatim}
mideon# klist
Ticket file:    /tmp/tkt0
Principal:      md.root@BSC.NO

  Issued           Expires          Principal
Mar 23 21:08:47  Mar 23 22:08:47  krbtgt.BSC.NO@BSC.NO
mideon# 
\end{verbatim}

Now we need to add the user to root's {\bf .klogin} file:

\begin{verbatim}
mideon# cat /root/.klogin
md.root@BSC.NO
\end{verbatim}

Now try doing the su:

\begin{verbatim}
[md@mideon.bsc.no 10407] su
Kerberos Password: 
Warning: tgt not verified.
\end{verbatim}

and take a look at what tokens we have:

\begin{verbatim}
mideon# klist
Ticket file:    /tmp/tkt_root_1250
Principal:      md.root@BSC.NO

  Issued           Expires          Principal
Mar 23 22:09:59  Mar 23 22:19:59  krbtgt.BSC.NO@BSC.NO
mideon# 
\end{verbatim}

Notice that with this setup each user has their own entry for su'ing to
root (the {\it user}.root entry in kerberos).  This can allow you to give root
access to multiple users without the need to share a common root password.
\end{document}