On Fri, Mar 06, 2020 at 12:48:50PM +0200, Alexander Bokovoy via FreeIPA-users wrote:
On pe, 06 maalis 2020, Sigbjorn Lie via FreeIPA-users wrote:
> > On 4 Mar 2020, at 14:27, Alexander Bokovoy via FreeIPA-users
<freeipa-users(a)lists.fedorahosted.org> wrote:
> >
> > On ke, 04 maalis 2020, Sigbjorn Lie via FreeIPA-users wrote:
> > > Hi Alex,
> > >
> > > Thanks for your prompt response.
> > >
> > > There are no Debian/Ubuntu systems in our environment.
> > >
> > > From your response, is the dual CA cert to be expected / by design?
> >
> > Yes, actually, it is to be expected for any setup with external CA root.
>
> This is not an external CA root. I presume both internal and external
> CA root is treated the same then.
Yes, there is no difference in this sense. In both cases Dogtag owns the
key -- the difference would only be where a self-signed root is located
in a CA path.
> > > I have not verified what certificate every application in our
> > > environment ends up utilizing yet, as serving both the old and the new
> > > CA certificates seem to me to be a bug, and I would rather fix the bug
> > > than make workarounds.
> >
> > No it is not a bug. It is normal and common to have multiple CA roots
> > available in a certificate store. The checks are done against a valid
> > CA root for the specific certificate and if you have one issued with the
> > use of older CA root certificate, you need to verify against that.
>
> This does not seem to be correct for IPA. As far as I recall there was
> a feature for making sure at that the renewed IPA CA certificate (when
> using self-signed CA cert) continue to work for the existing issued
> certificates. Verifying a certificate that was issues by the old CA
> against the new CA returns OK, and there are no issues connecting to
> the website.
>
> sudo openssl verify -verbose -CAfile /etc/ipa/ca-new.crt
/etc/pki/httpd/website1.crt
> /etc/pki/httpd/website1.crt: OK
openssl verification is done down to a self-signed trust anchor. If your
new CA root is using the same key (no re-keying happened on CA root
renewal), the same key is in place, and IPA CA is self-signed, that's
why it works. My understanding is that if you re-keyed CA root
certificate on renewal, this wouldn't be true and you would need the old
CA certificate to validate these server certificates.
I might be wrong here, though. See man page for openssl-verify, section
'VERIFY OPERATION' for some logic description.
> > What I'd like to get clear is why are you pointing the applications to
> > /etc/ipa/ca.crt? Supposedly, the content of this file is already a part
> > of the system-wide certificate store. On RHEL/CentOS/Fedora systems the
> > way how system-wide store works, there are multiple representations that
> > are supported by all crypto libraries and frameworks. So you don't need
> > to put a direct reference to /etc/ipa/ca.crt.
>
> We have been using IPA in production since 2012. In testing even a
> couple of years earlier. Back then the only place the ca cert was
> written to the client was /etc/ipa/ca.crt, and so this is what has been
> used in our Puppet setup ever since the beginning. The fact that the
> ipa-client installs the CA certificate in the system-wide certificate
> store is a more recent development.
> (
https://pagure.io/freeipa/issue/3504)
Understood. The ticket mentioned was closed in 2014, so we are talking
about all RHEL 7+/Fedora 19+ systems.
> > > Back to my original question, what is the reason for keep serving the
> > > old certificate? Would it not be sufficient to serve only the new
> > > certificate to new clients being enrolled and clients using the
> > > ipa-certupdate command?
> >
> > It is to allow clients to verify certificates issued with the previous
> > CA root certificate. Until you have renewed all certificates issued with
> > the old CA root, you need to keep that in place or clients/servers using
> > that wouldn't be able to trust the certificate.
>
> This is perhaps true for most PKI setups, however as mentioned, I seem
> to recall that a a feature for making sure at that the renewed IPA CA
> certificate (when using self-signed CA cert) continue to work for the
> existing issued certificates. Again, openssl returns OK when verifying
> existing certificates with the new CA, and there are no issues
> connecting to the website where this is hosted.
>
> sudo openssl verify -verbose -CAfile /etc/ipa/ca-new.crt
/etc/pki/httpd/website1.crt
> /etc/pki/httpd/website1.crt: OK
>
>
> As this duplicated CA cert is a feature, what will happen when we move
> pass the expiry date of the old CA? Will it be automatically removed
> from IPA or is there any manual cleanup required?
There is no automatic cleanup right now. I thought we had a ticket for
the clean up tool but I cannot find it right now. Please open one?
Rob recently implemented `ipa-cacert-manage delete` subcommand, on
master and ipa-4-8 branch (there hasn't been a release containing it
yet, though). It can be used to remove a specified certificate from
the IPA trust store. But it is not automatic.
If expired CA certs are present in trust stores, clients will (or
should) ignore them.
Cheers,
Fraser