[OPENLDAP] slapd password confusion

[Technical Home <technicalhome@aliceadsl.fr>]

Hello,

In my quest to install and understand how works a PDC Samba/OpenLDAP, I 
encountered a strange problem when setting my slapd admin password.
Here is my server configuration :

@(#) $OpenLDAP: slapd 2.4.11 (Oct 24 2008 23:44:05) $
  buildd@palmer:/build/buildd/openldap-2.4.11/debian/build/servers/slapd

I'm running ubuntu-server 8.10 Intrepid. My ubuntu is up to date. I 
installed the slapd package from ubuntu repository.
dpkg asked me to specify a password for my admin account and I entered a 
password like this one : totototo12;
And now when I try to modify my LDAP tree with the command "ldapmodify 
-x -D cn=admin,cn=config -W", at the password prompt, I can connect with 
all this password :
totototo12;
totototo12
totototo1
totototo
totototo23
tototototo
...

The only condition to login is that I wrote the beginning of my password 
: totototo
Why slapd does not care about the end of my password ?
If I specify a smaller password like toto12; in slapd configuration with 
dpkg-reconfigure, there is no problem...

If you need more informations to help me to undersatnd what happens, 
just ask me ;) .

Thanks in advance,
Gilles