On 02/09/2017 10:44 PM, Fraser Tweedale wrote: > On Thu, Feb 09, 2017 at 08:37:23AM +0100, Martin Kosek wrote: >> On 02/09/2017 02:12 AM, Fraser Tweedale wrote: >>> On Wed, Feb 08, 2017 at 10:19:54AM +0200, Alexander Bokovoy wrote: >>>> On ke, 08 helmi 2017, Martin Kosek wrote: >>>>> Hi Fraser and the list, >>>>> >>>>> I recently was in a conversation about integrating OpenShift with >>>>> FreeIPA. One >>>>> of the gaps was around generating a wildcard certificate by FreeIPA that >>>>> will >>>>> be used in the default OpenShift router for applications that do not >>>>> deploy own >>>>> certificates [1]. >>>>> >>>>> Is there any way that FreeIPA can generate it? I was thinking that >>>>> uploading >>>>> some custom certificate profile in FreeIPA may let us get such >>>>> certificate... >>>>> Or is the the only way we can add it by adding a new RFE in FreeIPA, >>>>> tracked in >>>>> [2]? >>>> Yes, we need a new RFE. There are checks in IPA that prevent wildcard >>>> certificates to be issued: >>>> >>>> - we ensure subject 'cn' of the certificate matches a Kerberos principal >>>> specified in the request >>>> >>>> - we validate that host object exists in IPA when the Kerberos >>>> principal is host/... >>>> >>>> We could lift off these two limitations for 'cn=*,$suffix' but there is >>>> still a need to apply proper ACLs when issuing the cert -- e.g. some >>>> object has to be used for performing access rights check. The wildcard >>>> certificate does not need to be stored anywhere in the tree, but a >>>> check still needs to be done. >>>> >>>> For example, for Kerberos PKINIT certificate which is issued to KDC we >>>> don't store public certificate in LDAP either but we do two checks: >>>> - a special KDC certificate profile is used to issue the cert >>>> - a special hostname check is done so that only IPA masters are able to >>>> request this certificate >>>> >>>> For the wildcard certificate I think we could have following: >>>> - use a separate profile for the wildcard, associated with a sub-CA >>>> - hardcode CN default in the profile to always be 'CN=*, >>>> O=$SUB_CA_SUBJECT' so that >>>> actual certificate ignores requested CN. >>>> - a special check to be done so that only wildcard-based subject >>>> alternative names can be added to a wildcard certificate request >>>> - all Kerberos principal / hostname checks are skipped. >>>> - actual ACL check is done by CA ACL. >>>> >>> Issuing wildcard certs is a deprecated practice[1]. I am not >>> dismissing the needs of OpenShift (or PaaS/IaaS solutions in >>> general) but I'd like to have a discussion with them about how >>> they're currently dealing with certs and whether a different >>> direction other than wildcard certs is feasible. Martin, who should >>> I reach out to? Feel free to copy them into this discussion. >> >> Right now, I am talking to a Solution Architect, i.e. someone who is building >> GAed solutions, not developers. This is not something we would change >> short-term anyway, this is how current OpenShift v2 or v3 behaves, despite >> the RFC. >> >> While I understand why having certificate *.lab.example.com and using it for >> my >> lab machines is a bad idea and increases the attack vector, I do not see it >> that way for OpenShift. There, applications get URL like >> "<app-dom>.myopenshift.test" and all is routed by one entity, the OpenShift >> broker. So the key.cert is on one location, just serving different names that >> are provisioned with OpenShift. >> >> I can understand that issuing a new certificate for every application >> provisioned by OpenShift and then renewing it complicates the design >> significantly. I am trying to be creative and see if current OpenShift could >> leverage FreeIPA CA and issue the broker cert, with current profile >> capabilities or with small change. >> > I believe OpenShift supports per-application certificates (i.e. when > app developers/maintainers supply their own cert for a custom > domain). So it might be possible in v2 or v3 to provision a cert > for every app.
Right, it supports this. But then issuing the certificate and renewal is a responsibility of app developer, AFAIK. I do not think if OpenShift has all the needed hooks to do this automatically and call certmonger for example. TLDR; adding a support of certmonger and issuing a certificate for every new application is a whole another degree of complexity than just issuing a Wildcard certificate for the router. I am not saying it should not be done, I am just saying that being able to generate a wildcard certificate with FreeIPA would let us integrate with OpenShift much better than now and with (hopefully) low effort involved, i.e. faster. > An automated solution does not yet exist but that > doesn't mean it can't be built out of what's currently GA. > >>> [1] https://tools.ietf.org/html/rfc6125#section-7.2 >>> >>> If we do go ahead with wildcard cert support in FreeIPA, some of my >>> initial questions are: >>> >>> - For the OpenShift use case, what is the "parent" domain name and >>> is it the same as the IPA domain name? Is it a subdomain of the >>> IPA domain name? >>> >>> - Do we need to support issuing "*.${IPA_DOMAIN}"? i.e. wildcard >>> cert under entire IPA domain name. >>> >>> - Do we need to support issuing "*.${IPA_HOSTNAME}"? i.e. wildcard >>> certs under names of IPA host principals. >> >> I do not know, but I can ask if it is important for you :-) >> > It's important to know what I actually need to do if we proceed with > implementing this :) We do not need to jump on implementing it right away, you already have a lot on your plate. Right now, I must just want to know: - is there any way how I can generate wildcard cert with current FreeIPA, using a custom certificate profile. I assume the answer is no. - how complex would it be to add support of Wildcard certificate support to FreeIPA (rough scope). Thanks, Martin -- Manage your subscription for the Freeipa-devel mailing list: https://www.redhat.com/mailman/listinfo/freeipa-devel Contribute to FreeIPA: http://www.freeipa.org/page/Contribute/Code
