[389-users] The case of a rather odd byte sequence (nsslapd-referral)

[Edward Z. Yang]

Hello all,

I've been using OpenLDAP to talk to Fedora DS, and my bindings
weren't working!  This was quite vexing, so I did some investigation.
I finally pinpointed the error to ldap_get_values_len() returning
a NULL pointer for nsslapd-referral, with no error code.

Sounds sort of like a bug in OpenLDAP, no?  Yes it does, but it's a bug
that's only tickled in very strange circumstances.  If you use ldapvi,
well, that links to OpenLDAP, but it ignores NULLs so that's why you
never see a nsslapd-referral in your cn=config entry.

I made a dump of the buffer that OpenLDAP was parsing values out
of (I think this was what was transmitted over the network.)

Exhibit A (byte sequence containing nsslapd-referral):

    0<14><04><10>nsslapd-referral1<00>0<19><04><12>

Exhibit B (byte sequence containing nsslapd-localhost):

    0,<04><11>nsslapd-localhost1<17><04><15>cats-whiskers.mit.edu0#<04><16>

As you can see, the byte sequence for nsslapd-referral appears to have
no textual data associated with it.  What's up with that?

Edward