Fraser Tweedale wrote:
> On Tue, Nov 11, 2014 at 04:17:37AM +0000, Les Stott wrote:
>>> -----Original Message-----
>>> From: Fraser Tweedale [mailto:ftwee...@redhat.com]
>>> Sent: Tuesday, 11 November 2014 1:59 PM
>>> To: Les Stott
>>> Cc: freeipa-users@redhat.com
>>> Subject: Re: [Freeipa-users] how to overcome same serial number in cert
>>> issue on different master servers?
>>>
>>> On Tue, Nov 11, 2014 at 02:11:55AM +0000, Les Stott wrote:
>>>>> -----Original Message-----
>>>>> From: Fraser Tweedale [mailto:ftwee...@redhat.com]
>>>>> Sent: Tuesday, 11 November 2014 12:51 PM
>>>>> To: Les Stott
>>>>> Cc: freeipa-users@redhat.com
>>>>> Subject: Re: [Freeipa-users] how to overcome same serial number in
>>>>> cert issue on different master servers?
>>>>>
>>>>> On Tue, Nov 11, 2014 at 01:40:50AM +0000, Les Stott wrote:
>>>>>> Hi,
>>>>>>
>>>>>> I have a standard rhel6 deployment for FreeIPA in two environments.
>>>>>>
>>>>>> One environment is in our Production Data Center, The Other in our
>>>>>> DR
>>>>> Data Center.
>>>>>>
>>>>>> Both environments are setup with the same domain (mydomain.com)
>>>>>> for
>>>>> FreeIPA. This is to support dr/failover etc.
>>>>>>
>>>>>> In each environment, there is a master. In Prod its
>>>>>> serverA.mydomain.com,
>>>>> In DR its serverB.mydomain.com.
>>>>>>
>>>>>> The master in each environment gets a generated certificate by
>>>>>> IPA. This
>>>>> certificate shows a Serial Number of "0A"
>>>>>>
>>>>>> My problem is that because the certificates have the same
>>>>>> Organization,
>>>>> OU and Serial Number, I can only browse to one of them (using Firefox).
>>>>>>
>>>>>> If I browse to https://serverA.mydomain.com/ipa/ui/ and accept the
>>>>> certificate it works fine.
>>>>>> If I then try to browse to https://serverB.mydomain.com/ipa/ui/ it
>>>>>> comes
>>>>> up with the following error:
>>>>>>
>>>>>> "Your certificate contains the same serial number as another
>>>>>> certificate
>>>>> issued by the certificate authority. Please get a new certificate
>>>>> containing a unique serial number. (Error code:
>>> sec_error_reused_issuer_and_serial)"
>>>>>>
>>>>>> If I remove the stored browser certificate for serverA, then
>>>>>> browse to
>>>>> serverB, and accept the certificate, it works, but then the "same
>>>>> serial number" error pops up for browsing serverA.
>>>>>>
>>>>>> Note: both environments were built separately and are not linked
>>>>>> in
>>>>> anyway (no replication between prod/dr).
>>>>>>
>>>>>> Is there a way to generate unique serial numbers for the masters?
>>>>>>
>>>>>> Thanks in advance,
>>>>>>
>>>>>> Les
>>>>>>
>>>>>>
>>>>>>
>>>>> Hi Les,
>>>>>
>>>>> Ideally, you should prevent this situation by using different common
>>>>> names
>>>>> (CN) for your CAs and server certifications across the different
>>>>> environments.  If this is not possible, you can configure the Dogtag
>>>>> CA to use random serial numbers:
>>>>>
>>>>>
>>> http://dogtagpki.org/wiki/Random_Certificate_Serial_Numbers#How_to_U
>>>>> se_Random_Certificate_Serial_Numbers
>>>>>
>>>>> This does not guarantee that you will not get serial number
>>>>> collisions, but reduces the likelihood.
>>>>>
>>>>
>>>> Thanks for the quick reply.
>>>>
>>>> In this case the common name is different between both environments.
>>>> In prod the master was serverA, in DR the master was serverB. It just
>>>> happened that way. So having a different CommonName doesn't help.
>>>>
>>> Do the CA certificates bear the same commonName?  This is probably what
>>> Firefox uses to determine if there are serial number collisions.
>>>
>>
>> It appears so.
>>
>> The certificate for the CA on the master serverA shows:
>>
>> Issued To
>> Common Name (CN) serverA.mydomain.com
>> Organization (O) mydomain.com
>> Organizational Unit (OU) <Not part of certificate>
>> Serial Number 0A
>> Issued By:
>> Common Name (CN) Certificate Authority
>> Organization (O) mydomain.com
>> Organizational Unit (OU) <Not part of certificate>
>>
>> The certificate for the CA on the master serverB shows:
>>
>> Issued To
>> Common Name (CN) serverB.mydomain.com
>> Organization (O) mydomain.com
>> Organizational Unit (OU) <Not part of certificate>
>> Serial Number 0A
>> Issued By:
>> Common Name (CN) Certificate Authority
>> Organization (O) mydomain.com
>> Organizational Unit (OU) <Not part of certificate>
>>
>>
>> Shouldn't the Common Name of the CA be different? Or is it the same in order 
>> to make CA replication easier?
>>
> Both environments were probably set up with the same CN for the CA
> (perhaps a default name).  I don't think this has anything to do
> with replication.
> 
>> Is there a way to re-issue certificates for the masters so they get unique 
>> serial numbers (without making the systems blow up)?
>>
> You can manually renew a certificate using Certmonger:
> 
>     http://www.freeipa.org/page/Certmonger#Manually_renew_a_certificate
> 
> You should enable random serial numbers before doing this.

The problem here isn't the server certs, it's the CA certs. He has two
CA's with the same subjects and serial numbers claiming to be the same
thing.

Honza added the ipa-cacert-manage command which can re-issue the CA
certificate, but I forget if this is only available in 4.1 or also 4.0.

You probably only need to do this on one of the masters.

As Simo pointed out though, having two environments with the same realm
should be avoided if possible.

rob

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