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Re: Help with authz-regexp mapping kerberos

Sorry I am not clear in my explanations.
What I am trying to achieve is to login to my linux and solaris boxes
from the console or through a remote ssh session using Active directory
or kerberos credentials and have that effectively map to my users that
exist in the LDAP directory.
And this works with a catch..

If the username in LDAP (joe_montana) matches the kerberos principal
name (joe_montana) I have no issue.. I login using the kerberos username
and password and the uid, gid, for that user in LDAP is correct when
issuing the id command. So effectively it uses the kerberos credentials
and logs me in as that ldap user. Pam-krb is used for authentication and
things seem beautiful.

However in this case, I have user's with the 8 character unix naming
convention(migrated from NIS). I am trying to find the correct way to
map that username to the kerberos username. There has got to be a way!!
Actually reading over the openldap Admin guide, I see that it mentions
using passthrough authentication to an Active directory server. Seems
this is done by modifying the userPassword attribute of the ldap dn.
As I understand from reading the guide, for my user jmontana the entry
should look something like this..

dn: cn=jmontana,ou-People,dc=example,dc=com
userPassword: {SASL}joe_montana@EXAMPLE.COM

However all the userPassword attributes for the users are encrypted. I
delete the dn's userPassword attribute first off. But when I attempt to
add the userPassword attribute with the ldif below I still get an
encrypted password in the userPassword attribute. How can I get the
entry to show {SASL}joe_montana@EXAMPLE.COM? Is there something in
slapd.conf or ldap.conf I need to modify? I may be barking up the wrong
tree but it sounds like what I need.

dn: uid=jmontana,ou=People,dc=example,dc=com
changetype: modify
add: userPassword
userPassword: {SASL}joe_montana@EXAMPLE.COM

Also the Openldap Admin guide mentions that "the server must be built
with the --enable-spasswd configuration option to enable pass-through
I am not sure how to check if this is the case. This is a RHEL5 box with
openldap-servers-2.3.27-8 rpm. I did not install from source, I used Red
Hat's precompiled RPM. Having to install from source is a whole other
can of worms. But I will do what I have to. 

Thank you much


1. Re: Subject: Re: Help with authz-regexp mapping kerberos
      identity	to	dn --RAHUL (Rahul Amaram)


Message: 1
Date: Sun, 17 Aug 2008 11:30:25 +0530
From: Rahul Amaram <rahul@synovel.com>
Subject: Re: Subject: Re: Help with authz-regexp mapping kerberos
	identity	to	dn --RAHUL
To: openldap-technical@openldap.org
Message-ID: <48A7BE79.2080704@synovel.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

This is the flow of events.

1. First GSSAPI (Kerberos) authentication takes place using the id

2. Then LDAP gives this the DN

3. Using authz-regexp, we can map this to another DN such as
"uid=jomontana,ou=People,dc=company,dc=com" which I believe makes sense
only to LDAP.

Getting back to your query, could you precisely define what is it that
you are trying to achieve? If you could give a clear step-to-step
example of the workflow, then I might be able to be of some assistance.


Chavez, James R. wrote:
> Rahul,
> Thank you again..I will try this expression you have provided.
> Am I going about this in the correct way? What I want is to login 
> through ssh or even the local box and be authenticated by the kerberos

> credentials. But I want the effective uid or account to be that of the

> ldap user in the openldap directory.
> I want my kerberos credentials to authorize my ldap login even though 
> the account names do not match. Is it possible with this authz-regexp?
> Or is this simply for services. 
> Sorry for all the questions.
> Thanks
> James
> Message: 1
> Date: Wed, 13 Aug 2008 15:08:43 +0530
> From: Rahul Amaram <rahul@synovel.com>
> Subject: Re: Subject: Re: Help with authz-regexp mapping kerberos
> 	identity	to dn	--RAHUL
> Cc: openldap-technical@openldap.org
> Message-ID: <48A2ABA3.9090900@synovel.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> Hi Chavez,
> Try this expression. It should work.
> authz-regexp uid=(.).*_([^,]*),cn=company.com,cn=gssapi,cn=auth
> uid=$1$2,ou=People,dc=company,dc=com
> The "sasl-realm" parameter is set in /etc/slapd/slapd.conf (main 
> slapd.conf file). You might also be interested in sasl-host (for 
> hard-coding the host sasl fqdn name to be used while fetching 
> ldap/<fqdn>@<REALM> password from the keytab file) and sasl-secprops 
> parameters.
> Regards,
> Rahul.
> Chavez, James R. wrote:
>> Rahul,
>> My friend finally a response.
>> Thank you for the input I had also read that link you provided, it 
>> was
>> somewhat helpful. If the usernames were identical that would work 
>> great I believe. However the source name is coming in as joe_montana 
>> and I need it to map to jmontana.
>> So I need only the first character of the first name and everything 
>> after the underscore (last name). I am looking for the expression 
>> that
>> would give me that. I am not too familiar with the expressions syntax

>> or how to manipulate them. I see there is an option to search ldap 
>> using ldap:///ou=people,dc=example,dc=com??one?(uid=$1), maybe I 
>> should look into that. Do you have any suggestions or source for 
>> reading on authz-regexp? I have been looking. If it was shell 
>> scripting I could manage another way.
>> When you say the SASL Realm would that go in the main slapd.conf or 
>> the /usr/lib/sasl2/slapd.conf?
>> I am indeed using GSSAPI for the SASL-auth-mechanism. I am getting 
>> close,just gotta get past this. :)
>> Thank you again.
>> James
>> ------------------------------

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