Re: [Samba] Samba authentication to Kerberos via OpenLDAP, third and last try

2008-04-04 Thread Wes Deviers
On Thu 3 Apr  2008 5:00:36 pm Wes Modes wrote:
 Volker Lendecke wrote:
  On Thu, Apr 03, 2008 at 01:34:30PM -0700, Wes Modes wrote:
  The question and the challenge:  Any leads on how I might convince Samba
  to pass the input password on to OpenLDAP so that OpenLDAP can
  authenticate it against Kerberos?
 
  The only chance is that you modify each client's registry to
  send plain text passwords to the server over the network,
  downgrading your security to what telnet provided ages ago.
  You can guess that this is ABSOLUTELY NOT recommended. If
  you go with standard Windows authentication schemes, the
  SMB server never sees the user's plain text password which
  would be required to authenticate against Kerberos.
 
  Volker

 Yeah, I'm not so keen on sending plaintext passwords anywhere.

 It is already moderately-well documented how to connect Samba up to use
 Kerberos authentication.  And my guess is that the Kerberos model would
 not allow passwords to be sent plaintext.  More likely an encrypted hash
 gets passed?  I don't know the precise mechanism, but would like to.

 But beyond that, how could one use Samba to pass that encrypted password
 to LDAP to pass on to Kerberos to authenticate?


Note: this is from my experience and research, both of which are extensive but 
probably wrong.  I wanted to do a similar thing (poor-man's SSO).

I believe the problem is twofold:

1) The client never actually sends the password.  By default, it sends a 
response to a challenge from the server; the response is based on the 
password.  So the password, in any form, never traverses the network unless 
you explicitly turn on that compatibility model.  Samba can't forward what it 
doesn't have.

2) Using LDAP for authentication is...a hack, to put it bluntly.  Everybody 
does it, but we probably shouldn't.  The problem is that in either 
authentication scenario (bind against LDAP = Good! or query the tree for 
user/pw/group/etc) would require modifications to the LDAP server.  It could 
accept the password, request a certificate and then store the token and 
return the Correct answer if the token is good and intentionally return 
an incorrect answer if the Kerb auth fails.

Since you can't send passwords in plaintext for obvious reasons, a simple or 
complex way to do this escapes me.  

I assume that you're not doing domain logins.  You could write a web interface 
or quick Java craplet (or a keylogger...) that takes a login from the user 
and captures their password.  Then you can feed that to a process on the LDAP 
server which authenticates against kerberos; if the authentication succeeds, 
you dump the hashed/crypted version of the password into the LDAP directory 
for authentication use later.  

Convoluted, but you could make it work.

Wes



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Re: [Samba] Samba authentication to Kerberos via OpenLDAP, third and last try

2008-04-03 Thread Volker Lendecke
On Thu, Apr 03, 2008 at 01:34:30PM -0700, Wes Modes wrote:
 The question and the challenge:  Any leads on how I might convince Samba 
 to pass the input password on to OpenLDAP so that OpenLDAP can 
 authenticate it against Kerberos?

The only chance is that you modify each client's registry to
send plain text passwords to the server over the network,
downgrading your security to what telnet provided ages ago.
You can guess that this is ABSOLUTELY NOT recommended. If
you go with standard Windows authentication schemes, the
SMB server never sees the user's plain text password which
would be required to authenticate against Kerberos.

Volker


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Re: [Samba] Samba authentication to Kerberos via OpenLDAP, third and last try

2008-04-03 Thread Volker Lendecke
On Thu, Apr 03, 2008 at 02:00:36PM -0700, Wes Modes wrote:
 It is already moderately-well documented how to connect Samba up to use 
 Kerberos authentication.  And my guess is that the Kerberos model would 
 not allow passwords to be sent plaintext.  More likely an encrypted hash 
 gets passed?  I don't know the precise mechanism, but would like to.

http://davenport.sourceforge.net/ntlm.html

Enjoy.

Volker


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Re: [Samba] Samba authentication to Kerberos via OpenLDAP, third and last try

2008-04-03 Thread Wes Modes



Volker Lendecke wrote:

On Thu, Apr 03, 2008 at 01:34:30PM -0700, Wes Modes wrote:
  
The question and the challenge:  Any leads on how I might convince Samba 
to pass the input password on to OpenLDAP so that OpenLDAP can 
authenticate it against Kerberos?



The only chance is that you modify each client's registry to
send plain text passwords to the server over the network,
downgrading your security to what telnet provided ages ago.
You can guess that this is ABSOLUTELY NOT recommended. If
you go with standard Windows authentication schemes, the
SMB server never sees the user's plain text password which
would be required to authenticate against Kerberos.

Volker
  
Yeah, I'm not so keen on sending plaintext passwords anywhere. 

It is already moderately-well documented how to connect Samba up to use 
Kerberos authentication.  And my guess is that the Kerberos model would 
not allow passwords to be sent plaintext.  More likely an encrypted hash 
gets passed?  I don't know the precise mechanism, but would like to.


But beyond that, how could one use Samba to pass that encrypted password 
to LDAP to pass on to Kerberos to authenticate?


W.

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Wes Modes
Server Administrator  Programmer Analyst
McHenry Library
Computing  Network Services
Information and Technology Services
459-5208
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