Dieter Kluenter wrote:
Am Wed, 29 Dec 2010 16:50:17 +0000 schrieb Brian CandlerB.Candler@pobox.com:
On Wed, Dec 29, 2010 at 07:57:43AM +0100, Dieter Kluenter wrote:
The default ssf of ldapi is 71, but you may change localSSF in slapd.conf(5). [...]
Thank you, that is very clear.
Having changed that, I can use EXTERNAL with minssf=112, but not GSSAPI. I find that if I set minssf=56 it's fine, but at minssf=57 it isn't.
It looks like this is a fundamental limitation of the GSSAPI: http://lists.andrew.cmu.edu/pipermail/cyrus-sasl/2006-September/000628.html http://lists.andrew.cmu.edu/pipermail/cyrus-sasl/2006-September/000635.html
FYI, here's what I see with minssf=57 (the 'No such attribute' error is somewhat confusing)
root@noc:~# ldapsearch ldap_sasl_interactive_bind_s: No such attribute (16) root@noc:~# ldapsearch -Y GSSAPI SASL/GSSAPI authentication started ldap_sasl_interactive_bind_s: Inappropriate authentication (48) additional info: SASL(-15): mechanism too weak for this user: mech GSSAPI is too weak
That is because Kerberos DES, und thus GSSAPI, only has a security strength factor of 56.
But this value is pure fiction, it's an arbitrary value hardcoded into the SASL gssapi plugin. Generally Kerberos is using triple-DES today, or AES.