Re: OpenLDAP with ssl client certs
Michael Ströder wrote:
Howard Chu wrote:
> Brent Bice wrote:
>> I was recently asked if we could use ssl client certs as a 2nd form
>> of authentication with OpenLDAP and didn't know for sure. Is it
>> possible to have OpenLDAP require both a DN/password pair *and* a client
>> ssl cert?
>
> You can make the server require a client cert, but it won't use the
> certificate identity for anything unless you Bind with SASL/EXTERNAL.
>
> http://www.openldap.org/doc/admin24/sasl.html#EXTERNAL
>
> And naturally, if you're using SASL, then the DN/password pair is ignored.
BTW:
In case of client certs the cert's subject-DN is the authc-DN which can be
directly used in authz-regexp which very much ties the mapping to subject-DN
conventions of the PKI.
But in some cases it would be very handy to map a distinct client cert to a
authz-DN by issuer-DN/serial or even by fingerprint. One use-case is cert
pinning of client certs and revocation checking done off-line.
Should I file an ITS for that?
I would reject such an ITS. Cert-pinning is an issue for clients that have a
very large collection of trusted CAs. The Admin Guide clearly states that
servers should only trust a single CA - the CA that signed its own certs and
the certs of its clients. In that case, no one else can issue a valid cert
with the same subjectDN.
--
-- Howard Chu
CTO, Symas Corp. http://www.symas.com
Director, Highland Sun http://highlandsun.com/hyc/
Chief Architect, OpenLDAP http://www.openldap.org/project/