[Freeipa-devel] [PATCH] 1059 single CRL generator

[Martin Kosek]

On 10/09/2012 04:43 PM, Rob Crittenden wrote:
> Martin Kosek wrote:
>> On 10/04/2012 06:17 PM, Rob Crittenden wrote:
>>> This changes the way IPA generates CRLs for new installs only.
>>>
>>> The first master installed is configured as the CRL generator. An entry is
>>> added to cn=masters that designates it.
>>>
>>> When a replica is installed it queries this entry so it knows where to forward
>>> CRL requests. CRL files are not available on cloned CAs (so /ipa/crl will
>>> return not found). It is possible to get a CRL directly from the clone CA via
>>> http://<hostname>:9180/ca/ee/ca/getCRL?op=getCRL&crlIssuingPoint=MasterCRL
>>>
>>> rob
>>
>> I tested new IPA server + replica with your patch and the CRL was now generated
>> only on the CRL master. I also tried OCSP (though this may not be relevant) and
>> it worked for me too.
>>
>> 1) I do not understand the following block in set_crl_master(self, suffix):
>>
>> +        try:
>> +            self.admin_conn.addEntry(entry)
>> +        except ldap.ALREADY_EXISTS, e:
>> +            root_logger.debug("failed to set CA as CRL generator")
>> +            raise e
>>
>> - when we hit ldap.ALREADY_EXISTS, we are actually OK because cn=CRL is set,
>> right?
>> - AFAIK, addEntry should  return our errors, i.e. errors.DuplicateEntry
>> - s/raise e/raise/
>>
>> I think you may have wanted to rather catch for more general LDAP error and
>> then report a real error and not just a debug note.
>>
>> 2) In get_crl_master:
>>
>> +        except Exception, e:
>> +            root_logger.debug("Could not connect to the Directory Server on
>> %s: %s" % (master_host, str(e)))
>> +            raise e
>>
>> s/raise e/raise/
>>
>> +        except errors.NotFound, e:
>> +            root_logger.debug("failed to find CA CRL generator")
>> +            self.crl_master = None
>>
>> - e is actually not used, "except errors.NotFound" would be enough
>>
>> 3) Majorish issue I hit with the actual CRL publishing on our server (F17). I
>> always get 403 Forbidden error when trying to download CRL from the CRL master:
>>
>> # wget --ca-certificate /etc/ipa/ca.crt https://`hostname`/ipa/crl/MasterCRL.bin
>> --2012-10-05 03:32:58--
>> https://vm-120.idm.lab.bos.redhat.com/ipa/crl/MasterCRL.bin
>> Resolving vm-120.idm.lab.bos.redhat.com... 10.16.78.120
>> Connecting to vm-120.idm.lab.bos.redhat.com|10.16.78.120|:443... connected.
>> HTTP request sent, awaiting response... 403 Forbidden
>> 2012-10-05 03:32:58 ERROR 403: Forbidden.
>>
>> I tracked the problem down to too strict permission on /var/lib/pki-ca
>> directory which is being published by httpd which does not have access to it:
>>
>> # ll /var/lib/pki-ca
>>
>> drwxrwx---. 11 pkiuser pkiuser 4096 Oct  5 03:00 pki-ca
>>
>> When I fixed the permission:
>> # chmod o+x /var/lib/pki-ca/
>>
>> I was able to get pass the Forbidden error and actually retrieved the CRL.
>> Adding Ade on CC list to follow on this permission issue.
>>
>>
>> I was thinking about usability of this new approach, we may want to make user
>> life easier in a perspective of CRL master managing. I have following
>> enhancements in mind:
>>
>> - mark CRL master in ipa-replica-manage list, or ipa-csreplica-manage list:
>>
>> # ipa-csreplica-manage list
>> Directory Manager password:
>>
>> vm-065.idm.lab.bos.redhat.com: master [CRL]
>> vm-120.idm.lab.bos.redhat.com: master
>>
>> - when removing master with CRL by "ipa-replica-manage del" we should warn user
>> and inform him what he should do next to amend the situation. I am thinking
>> about 2 new commands for ipa-csreplica-manage:
>>
>> * ipa-csreplica-manage crl-promote
>>    - promote current master as the new CRL master, enable CRL generation in
>> CS.cfg, mark master as the new CRL master in cn=masters
>> * ipa-csreplica-manage crl-update
>>    - update CS.cfg of current CA replica and point master.ca.agent.* to current
>> CRL master
>>
>> I can work on those enhancements if we agree on them.
>>
>> Martin
>>
> 
> Andrew provided some feedback out-of-band and my solution was overly complex.
> Here is a much simpler patch which does away with all the hand-waving around
> knowing who the CRL generator is.
> 
> rob

This looks OK code-wise, I will wait for dogtag guys to confirm that this is
the right approach.

Btw. I think we may want to file a RFE to implement some command to promote a
replica to CRL master (like "ipa-csreplica-manage crl-promote" proposed
earlier). Users may want to promote a replica when the master crashes or is to
be replaced. Some way to migrate CRL list (if not replicated already) to the
promoted replica would also be needed.

Martin