set_string/pkinit_cert_match

[Greg Hudson]

On 12/28/2017 02:05 PM, Pallissard, Matthew wrote:
> I'm having issues when trying to use set_string with pkinit_cert_match.   PKINIT does work when the SAN matches the user's principal explicitly.  It does not work when I try to map it to a user where the principal does not match the SAN.

The intended use case for pkinit_cert_match is client certificates which
weren't issued for use with PKINIT at all, and therefore have no
id-pkinit-san values.  If there is an id-pkinit-san value, the KDC
requires it to match the requested client principal.  Currently, the
only way to allow this is to disable the pkinit_san module:

  [plugins]
    certauth = {
      disable = pkinit_san
    }

You would then have to specify a pkinit_cert_match string for every
principal, as SAN matching would be turned off entirely.

If enough people have the use case where they want certificates with
mismatched id-pkinit-san values to be accepted based on matching
strings, we could provide a more convenient configuration hook for it.
I had (perhaps naively) assumed that if people were going to the trouble
of issuing client certs with id-pkinit-san values, they could include
values for all of the desired client principal names.