Hello Dinesh,
Dinesh Prasanth Moluguwan Krishnamoorthy [2020-06-03 20:17 -0400]:
I’m part of Dogtag PKI open-source project [1]. Our team strives to
provide
enterprise-class open-source Public Key Infrastructure (PKI) [2].
FTR, Simon Kobyda (CCed) is working on a Cockpit page for managing certificates
[1]. There may be some overlap here, so perhaps you can meet and exchange some
ideas.
1. According to [3] Cockpit seems to require the host to join the
IdM
domain in order to authenticate PKI users into Cockpit using client cert
auth. Is it possible to use client cert auth without joining a domain? Will
that require major changes in Cockpit?
To be precise, Cockpit calls sssd to map a given certificate from TLS client
cert auth to a user [2], with FindByCertificate().
This doesn't *inherently* require IdM. It's just (1) the only way how I got
that sssd lookup mechanism to actually work, and (2) it generally makes sense
to maintain this cert→user mapping centrally.
Allegedly it is possible to configure sssd to do this mapping with local
certificates [2]. I played around with that a few weeks ago, as that would be a
very interesting use case, but I didn't manage to get it working -- apparently
the FindByCertificate() sssd method only works with IdM, not with these local
certificates. Making that work may be an interesting project.
So this all hinges on sssd -- if that can map a certificate, you can log into
Cockpit. Cockpit itself would need no modifications for backends other than
FreeIPA.
2. Suppose the user has been authenticated into Cockpit using a
client cert
as described in #1, is it possible for Cockpit to use the same client
certificate auth to access PKI server? Or do we need to use a different
auth mechanism?
As Fraser already pointed out, cockpit's web server doesn't have the private
key that the browser end was using to authenticate, so that doesn't work.
Does it have to be TLS client cert auth, or would kerberos work as well? We
are currently designing that so that we can "forward" (or rather,
convert/transcend) the initial client cert auth to a kerberos ticket, so that
cockpit can use that to further authenticate to services like sudo or ssh.
Structurally that's very similar, but it would require the PKI server to accept
delegated (S4U) kerberos tickets.
Martin
[1]
https://github.com/skobyda/cockpit-certificates
[2]
https://docs.pagure.org/SSSD.sssd/design_pages/lookup_users_by_certificat...
[3]
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/...
[4]
https://projects.engineering.redhat.com/browse/COCKPIT-542 -- RH internal only