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

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.

> 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.

happy configuration party :)

On 29/05/12 00:00, Bernd May wrote: > Hey, > > 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 >> entry. > 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 > use_first_pass > > 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).

On 29/05/12 08:18, Christian Manal wrote: > Hi, > > what Kerberos implementation are you using? If it's Heimdal and if it > uses your OpenLDAP server as its storage backend, you can use the > smbk5pwd overlay to set the Kerberos password along with a regular > password change. > > If your distro doesn't ship it with OpenLDAP or as a seperate package, > you can build it from source. It's in the tarball under > > contrib/slapd-modules/smbk5pwd/ > Hi Christian, I'm going to use MIT kerberos as that is what I am used to and I trust it and my abilities to fix it :) But what you've said about smbk5pwd is interesting. So Overlays are the plug-ins that can hook into parts of the process, including a password change? That is very useful knowledge - I can have a hunt for some others if smbk5pwd does not support MIT password changes - and I am aware that beyond ticket granting the wire protocols do differ. If I'm desperate enough, I feel reasonably confident I could copy and modify that overlay - even if it is just to fork/exec to kadmind. Many thanks for your time - very useful stuff! All the best, Tim

There's a SLAPI plugin for 389 DS which supports MIT Kerberos. A C programmer might be able to adapt this as an OpenLDAP overlay (similar to OpenLDAP's slapo-smbk5pwd).

On 29/5/2012 7:42 μμ, Michael Ströder wrote: > There's a SLAPI plugin for 389 DS which supports MIT Kerberos. A C programmer > might be able to adapt this as an OpenLDAP overlay (similar to OpenLDAP's > slapo-smbk5pwd). Sorry, couldn't one use the SLAPI plugin as is in OpenLDAP, since SLAPI support is available (SLAPI plugins are supposed to be able to work without modifications on all LDAP servers)?

(For example, Symas and LTB packages are SLAPI-enabled; I had tested such a SLAPI plugin and it worked fine.)