[Freeipa-users] how to overcome same serial number in cert issue on different master servers?

[Les Stott]

> -----Original Message-----
> From: Fraser Tweedale [mailto:ftweedal at redhat.com]
> Sent: Tuesday, 11 November 2014 1:59 PM
> To: Les Stott
> Cc: freeipa-users at 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:ftweedal at redhat.com]
> > > Sent: Tuesday, 11 November 2014 12:51 PM
> > > To: Les Stott
> > > Cc: freeipa-users at 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?

Is there a way to re-issue certificates for the masters so they get unique serial numbers (without making the systems blow up)?

Thanks,

Les