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Re: Kerberos double binding creates no bindings (ITS#433)
On Thu, 27 Jan 2000, Mark Adamson wrote:
> Hello all.
> I am working on getting OpenLDAP 2.0 working for the CMU campus
> here. I CVS downloaded the source in early December and have it
> compiled and running on my desktop machine.
> I am working on getting Kerberos authentication working, and ran
> into what I'd have to call a bug. It has to do with a client such as
> ldapsearch uses ldap_kerberos_bind_s() and how the server binds your
> DN using do_bind().
> When a client uses ldap_kerberos_bind_s() it first binds with an
> authmethod LDAP_AUTH_KRBV41 (the "ldapserver" ticket), and then again
> with LDAP_AUTH_KRBV42 (the "x500dsa" ticket). On the server, in the
> the first bind does all of the leg work of checking the krbName and
> returns 0 to the calling function
> The second bind on the server simply sends a SUCCESS message back to
> the client and returns a non-zero code back to do_bind(), with the
> comment "stop front end from sending result".
> When do_bind() was called, it first cleared any previous bindings and
> then if the backend bind returns 0 it will store the requested DN in
> the connection.
> The bug is that the second (LDAP_AUTH_KRBV42) binding in
> ldbm_back_bind() always returns a non-zero code to do_bind(), so the
> DN binding from the first binding was erased and not stored the second
> time. The result is a connection that has NO binding: you are
> I am curious as to why the second binding wants to send the SUCCESS
> message itself and return !0, instead of returning 0 and letting
> do_bind() return SUCCESS (and set the DN binding).
- The whole double-bind thing is a hack from the Umich code when
ldap was more integrated into the whole X500 environment. If you
are running slapd, there is really no point to doing anything
besides LDAP_AUTH_KRBV41. It's my understanding that the original
idea was to authenticate to both the ldap server and the X500
DSA. I have no idea why this was done, but since X500 DSA's have
gone the way of the dodo, there is really no point in doing it
- Booker C. Bense