Re: FW: postgres kerberos how to

Nope, no Unix accounts are necessary besides the one that PG runs as.
You do need the PG roles, however. Good luck!

garner

________________________________

From: Derrick Stensrud [mailto:dstensrud(at)worleyco(dot)com]
Sent: Wednesday, December 20, 2006 10:36 AM
To: Garner Chung
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: FW: [GENERAL] postgres kerberos how to

Great! Thanks so much, I'm going to try to get this going right now.
Do I need unix user accounts?

Garner Chung wrote:

Hey, I think this made it to the list. But I had also CC:ed you
separately -- to which I got a bounce back. So here's my second
attempt
to essentially CC: you.

garner

-----Original Message-----
From: Garner Chung
Sent: Wednesday, December 20, 2006 10:10 AM
To: 'pgsql-general(at)postgresql(dot)org'
Cc: 'Derrick Stensrud '
Subject: RE: [GENERAL] postgres kerberos how to


Hey Derrick,

I work with Matt, and I was involved in our Kerberos
implementation.
I'll try to answer your questions...

- You only need to make the mapping to an Active Directory(AD)
user once
for that PG service. What that ktpass command does is map the
principal
name for your PG service to an AD user. More importantly, with
the
resulting keytab file you will establish the shared secret
between the
service(PG) and the KDC(which is really a close partner if not
subset of
AD). The secret is what AD will use to identify itself as a
trustable
KDC to PG. So, no, you do not need to do that for every PG user.
However, you do need to create each database user in both AD and
PG.
- +rndPass (which is not available in older versions of ktpass)
will use
a random shared secret(password). There's no need for anyone to
know
what the actual value of that pre shared key is. However it is
very
important that the resulting keytab file is protected via
filesystem
permissions.
-
* Yes that keytab file needs to be in /etc/krb5.keytab which
is an
MIT library file location. I don't think PG will look at that
file
directly. In fact, you specify separately in postgresql.conf
where PG
should look for its keytab file. As far as we understand that
/etc/krb5.keytab file would contain multiple keytabs. If any MIT
Kerberos experts out there could chime, please do. ie. Would
should the
permissions on that file be set to? To be clear, we got an error
message, which I never wrote down, without PG's keytab file not
there
also.
* Yes, you also need to edit your /etc/krb5.conf file. You
are
essentially telling the MIT Kerberos library that the default
realm for
it is the AD realm/domain. You are also telling it where the KDC
for
that realm is.
* You also need edit postgresql.conf where its keytab is.

Hope this helps, please do follow up with clarifying questions
if you
have any. There is, IMHO, a paucity of good documentation on
getting PG
to authenticate against AD using Kerberos.

garner


________________________________

From: Derrick Stensrud [mailto:dstensrud(at)worleyco(dot)com]
Sent: Wednesday, December 20, 2006 5:07 AM
To: Matt Burry
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: [GENERAL] postgres kerberos how to


Thanks, I'm going to go ahead and try to implement postgresql
kerberos
against active directory 2003 today. I read a bit about it last
night
and have a few questions.

You wrote: "

* Map PG on database server as a user in Active Directory
o Create user account in AD for PG service

ie. 'postgres_fauxacacia'

o Make keytab file with AD PG user account. This will
also map
the user to the service.

ktpass princ postgres/FAUXACACIA(at)FAUX(dot)COM -mapuser
postgres_fauxacacia
+rndPass -out postgres_fauxacacia.keytab -target fauxsol -ptype
KRB5_NT_PRINCIPAL
"

Questions:
- If I have 10 users in postgresql do I need to run this ktpass
program
for each user? If so would I always keep the princ paramater
listed as
"postgres/FAUXACACIA(at)FAUX(dot)COM"
<mailto:postgres/FAUXACACIA(at)FAUX(dot)COM>
<mailto:postgres/FAUXACACIA(at)FAUX(dot)COM>
<mailto:postgres/FAUXACACIA(at)FAUX(dot)COM>
and do the capitals matter in this command?
- With this ktpass command, what is the +rndPass option? I'm
used to
seeing something like -pass P(at)ssWoRd
- After this keytab file is created, I copy it to
/etc/krb5.keytab on
the linux box, and I edit my krb5.conf file to resemble yours
listed.
Is there anything else that has to be done on the Windows or
linux side?

Thanks for the help so far.




Matt Burry wrote:




From: pgsql-general-owner(at)postgresql(dot)org
[mailto:pgsql-general-owner(at)postgresql(dot)org] On
Behalf Of
Derrick
Sent: Tuesday, December 19, 2006 5:52 PM
To: pgsql-general(at)postgresql(dot)org
Subject: [GENERAL] postgres kerberos how to

I was wondering if anyone out there could point
me in
the
right direction. I'm looking for a decent how
to on
using
postgresql's built in kerberos support to
authenticate
against windows 2003 active directory. I was
trying to
use
pam_ldap, but had to give up and decide on using
kerberos
instead. Any help what so ever is much
appreciated.
Thanks.




Derrick,

We've been setting it up in our shop and it's been a bit
of a
bear. We're connecting to PG through the ODBC driver using both
PG 8.1
and 8.2. Below are the steps we've taken to get it to work with
a
Windows 2003 Domain Controller and Windows 2003 Server running
Terminal
Services which serves the front end. We have had greater success
with
Windows 2003 Server R2, though we have been able to get it to
work with
Windows 2000 Server and Windows 2003 server. We also needed to
use MIT's
Net ID manager.

It would great if others could point to ways that we
could
simplify these steps. I wasn't the one here who implemented
things, so
one of my colleagues may need to followup if there are specific
questions. Additionally, we have not looked into the suggestion
that
Magnus made that 8.2's LDAP support could help solve this
problem of AD
integration from a slightly different direction.

-Matt


Kerberos Configuration Steps
**************************

PG Server=fauxacacia
Active Directory Domain=faux.com
Active Directory Domain Controller=fauxsol
Windows 2003 Server R2 (Terminal Services server, in our
case,
used to serve our front end)=fauxsaturn

On Domain Controller: fauxsol(Windows 2003)

* Add entries to Domain Controller/DNS for all
relevant
servers so that all principals can contact each other by name.

192.168.4.26 fauxsol fauxsol.faux.com
192.168.4.28 fauxacacia fauxacacia.faux.com
192.168.4.29 fauxsaturn fauxsaturn.faux.com


On PG Server: fauxacacia(Linux)

Samba

* Install Samba to facilitate copying of keytab file
from
Windows Domain Controller

NTP (Network Time Protocol to make sure that servers
stay with
same time, required with Kerberos)

* Install package, ntpdate
* Edit '/etc/default/ntpdate' to point to the
Windows Domain
Controller/KDC Server

# servers to check. (Separate multiple servers with
spaces.)
#NTPSERVERS="pool.ntp.org"
#NTPSERVERS="ntp.ubuntu.com"
NTPSERVERS="fauxsol"
#
# additional options for ntpdate
#NTPOPTIONS="-v"
NTPOPTIONS="-u"

* Add an hourly cron entry,
'/etc/cron.hourly/ntpdate', and
make it executable, 'chmod ugo+x /etc/cron.hourly/ntpdate'

#!/bin/sh

NTPDATE=/usr/sbin/ntpdate
NTPDEFAULTS=/etc/default/ntpdate
NTPFALLBACK="ntp.ubuntu.com"

if [ -f "$NTPDEFAULTS" ]; then
. $NTPDEFAULTS
test -n "$NTPSERVERS" || NTPSERVERS=$NTPFALLBACK
else
NTPSERVERS=$NTPFALLBACK
fi

if [ -x "$NTPDATE" ]; then
$NTPDATE -s $NTPOPTIONS $NTPSERVERS
fi

* Restart cron, '/etc/init.d/cron restart'

MIT Kerberos Library

* Install Kerberos Libraries

krb5-config, krb5-user

* Edit Kerberos config files ('/etc/krb5.conf')

[libdefaults]
default_realm = [faux.com]
krb4_config = /etc/krb.conf
krb4_realms = /etc/krb.realms
kdc_timesync = 1
ccache_type = 4
forwardable = true
proxiable = true

[realms]
FAUX.COM = {
kdc = [fauxsol]
admin_server = [fauxsol]
}

DNS

* Edit DNS settings file ('/etc/resolv.conf')

nameserver [ip address of DNS server 1]
nameserver [ip address of DNS server 2]

On Domain Controller: fauxsol (Windows 2003)

* Install Windows Supporting Tools (ktpass), found
on
Windows installation CD as SUPPORT\TOOLS\SUPTOOLS.MSI
* Map PG on database server as a user in Active
Directory
o Create user account in AD for PG service

ie. 'postgres_fauxacacia'

o Make keytab file with AD PG user account.
This will
also map the user to the service.

ktpass princ postgres/FAUXACACIA(at)FAUX(dot)COM -mapuser
postgres_fauxacacia +rndPass -out postgres_fauxacacia.keytab
-target
fauxsol -ptype KRB5_NT_PRINCIPAL

[edit]
On PG Server: fauxacacia (Linux)

* Move keytab file to PG Server (Linux).

'/usr/local/pgsql/etc/krb5.keytab' and
'/etc/krb5.keytab'

* Secure keytab files
o 'chown postgres:postgres
/usr/local/pgsql/etc/krb5.keytab'
o 'chmod ugo-wx
/usr/local/pgsql/etc/krb5.keytab' -
Files created by samba have executable bit set for user.
o 'chmod go-r
/usr/local/pgsql/etc/krb5.keytab'
* Configure PG to use
'/usr/local/pgsql/etc/krb5.keytab'

# Kerberos
krb_server_keyfile = '/usr/local/pgsql/etc/krb5.keytab'
# (change requires restart)
#krb_srvname = 'postgres' # (change
requires
restart)
#krb_server_hostname = '' # empty string
matches
any keytab entry
# (change
requires
restart)
#krb_caseins_users = off # (change
requires
restart)

* Restart PG

[edit]
On Front End Server: fauxsaturn (Windows 2003)

* Install MIT Kerberos For Windows
o Make sure that Net ID Manager is configured
to start
when user logs in(default).
* Create 'C:\Program
Files\MIT\Kerberos\bin\krb5.ini':

[libdefaults]
default_realm = FAUX.COM
kdc_timesync = 1
ccache_type = 4
ticket_lifetime = 36000

[realms]
FAUX.COM = {
kdc = FAUXSOL
admin_server = FAUXSOL
}

[appdefaults]
autologin = true
forward = true
forwardable = true
encrypt = true

* Delete all krb5_32.dll's other than the one in the
MIT\Kerberos\bin folder.

ie. 'C:\Program Files\psqlODBC\0802\bin' or
'C:\Program Files\pgAdmin III\1.6'

o This ensures that all client side PG
Kerberos
authentication will occur via the just installed MIT Kerberos
for
Windows package.
o The secondary, desired effect is that only
the one
MIT\Kerberos\bin\krb5.ini file is used.
o NOTE: This is just for our Terminal Services
environment: If the krb5.ini file is placed in 'C:\Windows',
then
Kerberos authentication will fail unless the session is in
install
mode('change user /install'). This is because of the virtualized
copy of
the C:\Windows directory that is created in a Terminal Services
Session.
In particular, INI files are managed by a sync process between
the
virtual/personal Windows directory and the real one. Entering
install
mode points the user's session to the _real_ Windows directory.
+ As long as there is the one
'C:\Program
Files\MIT\Kerberos\bin\krb5_32.dll' and the one 'C:\Program
Files\MIT\Kerberos\bin\krb5.ini', there 'change user /install'
should
not be necesssary.




--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.15.25/593 - Release Date:
12/19/2006 1:17 PM



--
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.15.25/593 - Release Date:
12/19/2006 1:17 PM