On Wed, May 03, 2023 at 10:17:03PM -0000, Djerk Geurts via FreeIPA-users wrote: > > Not all IPA users can create DNS records. One needs to be able to create > > the TXT entry for the challenge to succeed. > > I think this is the crux of it. How does an anonymous ACME client > authorise anything? > Yes the http-01 challenge. Examples:
- https://frasertweedale.github.io/blog-redhat/posts/2020-05-06-ipa-acme-intro.html#demo-certbot-client-running-standalone-http-server - https://frasertweedale.github.io/blog-redhat/posts/2020-05-07-ipa-acme-mod_md.html > Or can an ACME client only be used from an > enrolled host? In which case Certmonger is already available. > > My reason for asking is that I'm looking into whether I can use > acme.sh from an appliance like VMware vCenter, which would not be > an enrolled host. I've used another ACME client (dehydrated) and > set it to update DNS via RFC2136 for Let's Encrypt certificates. > Where the authorisation was done through the TSIG key for the > DNS-01 update on the DNS server. > > What mechanism other than Kerberos is available to authorise ACME > certificate requests from FreeIPA? > FreeIPA/Dogtag ACME service supports http-01 and dns-01 challenges. http-01 does not involve communication between the ACME client and IPA server. The ACME client need not be IPA enrolled. dns-01 requires the client to communicate with a DNS provider. If that happens to be the IPA server, then the client does need an IPA account + privileges to manage the DNS entries, and will use Kerberos authentication. > Looking at things like this example which uses HTTP-01. It looks > like any FreeIPA host can request a certificate as long as the DNS > entry matches. However, as I type this I guess the requirement is > still to have a Service Principal configured? As you can see, the > more I think about this the more questions I have... > > - HTTP-01 auth ensures the ACME client can verify it has control > of the service that hosts the FQDN for the certificate. > > - I assume that a Service Principal is still a requirement for an > ACME client request, as it is for Certmonger requests. It is > likely a stupid question, but worth asking IMHO. > IPA principal is NOT required to use ACME. > - DNS-01 auth, how does an ACME client signal it has the > privileges required to request a certificate for the FQDN in > question? > The ACME server offers the challenges - in the default configuration *both* http-01 and dns-01 are offered. The client chooses which to attempt. The client then "sets up" the required info - either preparing a particular HTTP resource (http-01), or creating a particular DNS resource (dns-01). If the client successfully completes the set-up, it then informs that such-and-such challenge was completed and should be validated. If the server successfully validates the challenge, then the corresponding identifier (i.e. DNS name) is authorized for that client. The only scenario where this would involve the ACME client authenticating to IPA server is when using dns-01 challenge and IPA DNS provider. > I can guess, but when it comes to security I think it's > best not to. I hope this has clarified the situation for you. Cheers, Fraser _______________________________________________ FreeIPA-users mailing list -- freeipa-users@lists.fedorahosted.org To unsubscribe send an email to freeipa-users-le...@lists.fedorahosted.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedorahosted.org/archives/list/freeipa-users@lists.fedorahosted.org Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
