[SSSD] [PATCH] Add ldap_sasl_minssf option

Simo Sorce simo at redhat.com
Wed Nov 30 18:29:20 UTC 2011


On Wed, 2011-11-30 at 17:28 +0100, Jan Zelený wrote:
> > On Wed, Nov 30, 2011 at 09:31:05AM -0500, Rob Crittenden wrote:
> > > Jakub Hrozek wrote:
> > > >On Tue, Nov 22, 2011 at 12:45:14PM +0100, Jan Zelený wrote:
> > > >>https://fedorahosted.org/sssd/ticket/1075
> > > >>
> > > >>The only thing is that I'm not sure if 72 is the right default minssf
> > > >>value for IPA provider, as default IPA installation works with 56 as
> > > >>the highest possible value for me. In default SSSD installation, this
> > > >>means that communication with IPA server will be rejected with no
> > > >>information about the reason being min SSF. I think this will be very
> > > >>confusing to SSSD users.
> > > >>
> > > >>Can anyone give me a hint how to proceed? Lower the default value in
> > > >>SSSD or do the change in IPA?
> > > >>
> > > >>Thanks
> > > >>Jan
> > > >
> > > >The patch itself looks good to me.
> > > >
> > > >I don't know what's causing the problem, though. I think that the SSF
> > > >requirement is set in nsslapd-minssf attribute in cn=config on the
> > > >server side. My (quite recent) IPA server install has the option set to
> > > >0, which means "no restrictions".
> > > >
> > > >Rob, is there any other place on the server that sets the SSF values?
> > > 
> > > Yes that is the right direction and the 389-ds and IPA default is 0.
> > > There is a nsslapd-localssf option as well which I believe only
> > > applies to ldapi.
> > > 
> > > rob
> > 
> > Ok, I'm confused now.
> > 
> > When I perform an GSSAPI search, ldapsearch reports "SASL SSF: 56".
> > Where does it come from? Is there any override in cyrus-sasl perhaps?
> > (The openldap source says the value comes from sasl_getprop(), I haven't
> > looked deeper yet)
> > 
> > $ ldapsearch -Y GSSAPI -O "minssf=56" -b cn=example,dc=com uid=admin
> > SASL/GSSAPI authentication started
> > SASL username: host/ipa.example.com at EXAMPLE.COM
> > SASL SSF: 56
> > SASL data security layer installed.
> > <LDIF follows>
> > 
> > Setting -O "minssf=$value" to anything above 56 then gives:
> > SASL(-4): no mechanism available: No worthy mechs found
> 
> My suspicion was that IPA server doesn't offer encryption method stronger than 
> whatever SSF=56 means. In this context, perhaps no key strong enough in the 
> keytab?

GSSAPI offers stronger encryption. It looks like SASL and GSSAPI do not
talk at some level and SASL always sets 56.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York




More information about the sssd-devel mailing list