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Re: Very quick pointer

On 29/05/12 00:00, Bernd May wrote:

On 05/28/2012 10:25 PM, Tim Watts wrote:
1) Rig OpenLDAP so all password changes get sent to the kerberos
server but do not use it for authentication. In the meantime we will
continue authenticate with the SSHA1 hashes in the user's LDAP
The usual way to do this on most *nix systems is to actually 'rig' the
PAM. In debian for example you setup your /etc/pam.d/common-password to
contain something like:

password   sufficient pam_krb5.so ignore_root
password   required   pam_unix.so nullok obscure min=4 max=8 sha256

this sets up most of your tools to use the right modules when changing
the password, e.g. 'passwd'.

Hi Brend,

Thanks for the reply.

Unfortunately there's a problem with that - the user would need their old kerberos password before they could initiate a change and in this case, their old kerberos password is unknown because Kerberos has only just existed.

I do not know if you could do something like 'referring' a password
change request from the OpenLDAP server to the kerberos server but since
this would be an invitation von mitm attacks I doubt it.

It will be a bit of a pity in this case if it's not possible :(

When using password hashes in the user entry, does slapd receive the plaintext password or does the client generate the hash?

If slapd does not have a mechanism specifically for forcing (priming) kerberos servers, does it have a password change hook?

Otherwise, I am going to have to provide a special password change service somewhere - probably web based or something.

Or crack all the LANMan hashes I found in the original LDAP server! (Just joking).

2) After some time (months) when everyone has eventually done a
password change, the Kerberos server will be well enough in sync. Now
I would like to switch OpenLDAP to using kerberos on the backend (ie
for binds etc) and I will purge the SSHA1 hashes.

We successfully auth against kerberos with our LDAP, you might be
interested in reading the SASL section of man slapd-config. Make sure
you ahve compiled your OpenLDAP with SASL support and have successfully
kerberized your server.

Thanks! That sounds good :)

happy configuration party :)

All the best,

Tim Watts
Personal Blog: http://www.dionic.net/tim/