Ana Kukec escribió:
Hi Marcelo,

Tnx for the comments, please see my comments below..


marcelo bagnulo braun wrote:

2.  Introduction

  Secure Neighbor Discovery [RFC3971] Utilizes X.509v3 certificates for
  performing router authorization.  It uses the X.509 extension for IP
  addresses to verify whether the router is authorized to advertise the
  mentioned IP addresses.

s/addresses/prefixes

  The SEND specification does not describe the set of extensions that
  need to be supported

This is strictly true, right? I mean section 6.3.1. Router Authorization Certificate Profile of the send spec does define the cert profile.


The send spec describes just the X.509 IP address extension in the section 6.3.1 RAC profile, and indirectly the Subject name and the subjectAltName extension in the section 6.4.3 TA option.


then it reads

5.  Backward Compatibility

  The disadvantages of this model are related to the fact that the SEND
  specification was developed before the standardization of the RPKI.
  Hence, SEND is not completely compliant with the RPKI specifications
  since it defines its own IP prefix validation routine and it is not
  suitable for the use with CRLs, while the RPKI suports only CRLs.
  This means that SEND implementations supporting this profile will not
  be able to interoperate with legacy SEND implementations.

I don't fully understnad the implications of this
I mean, what needs to be changed in a current send implementation to be compatible with this new format? I mean, the optimal would be that current send implementations accept RPKI certs but skip the new extensions and that new send implementations are able to read the new extensions defined by this document. is this not possible?


The incompliances between the RPKI and SEND are related to the X.509 extensions profile and their validation. Regarding the acception of the RPKI certificate profile into SeND, there are two problematic extensions, the EKU extension (as we already discussed)

right, but my question is what happens when a current send node receives a cert with the EKU? does it fails, or does it just skipe the option takes the cert as valid?

and the subjectAltName extension. The send spec requires the usage of the subjectAltName extension in order to match its contents with the Trust Anchor option of the FQDN type (as described in the section 6.4.5 of the send spec). But, since the RPKI is about the authorization and not about the authentication, the subject names in RPKI are not intended to be descriptive, and thus the RPKI certificate profile, i.e. draft-ietf-sidr-res-certs-16 does not use/describe the subjectAltName extension at all.
So, this seems to psoe two problems:
- first, that a current send node will not accept as valid a cert without the subjectAltname, right? While this is not optimal, we may be able to live with that - second, how does a send node uses the subjectAltName? i mean does the send node needs this information to validate the anchor point? If so, how do we deal with this?


Regarding the validation routines, the rfc3779 extension validation routine conflicts with the one described in the send spec. But together with the RPKI certificate profile we can accept the rfc3779 extension validation routine.

not sure waht do you mean here... can we still use the send validation routing? Or we need to change the send nodes to do the new validation routine?

Contrary to the X.509 extensions and the validation routines, the revocation is not a conflicting thing, it is just that the SeND lacks the text describing how to incorporate the RPKI revocation into SeND. With carefully chosen validity intervals for the RPKI certificates on the lower tiers, i.e. at the SEND level, the CRL is not expected to grow to large sizes, and it can fit well into the SEND messages.
right, but do we need to specify the revocation routines as well?

I would like to understnad if we need to update rfc3971 to support this, i understnad we do. I am not sure i fully understnad what are the updates that are needed to rfc3971... could you elaborate on this?

regards, marcelo



Regarding the section 4.1. EKU extension, we will describe it more in details, in collaboration with the sidr wg.

Ana



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