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Re: OpenLDAP with ssl client certs

Michael StrÃder 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.


And naturally, if you're using SASL, then the DN/password pair is ignored.


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/