Fraser Tweedale via FreeIPA-users wrote:
> 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.
I should point out that the delete command deletes ALL certs for a
nickname so it wouldn't help in this particular case.
Thanks for the clarification, Rob.
If you need to remove just a single cert for the same subject (e.g.
an older expired one), you can delete that particular
userCertificate attribute value from its LDAP entry under
cn=certificates,cn=ipa,cn=etc,{basedn}.
I also want to clarify that it is expected behaviour for IPA will
put all trusted CA certs, including possibly expired variants, in
the /etc/ipa/ca.crt and other system trust stores. If it is causing
an issue for some other program, the problem is with that program,
not with FreeIPA.
Thanks,
Fraser