Hi Roman, thanks for your feedback. Comments inline. On 7/31/23 1:03 PM, Roman Danyliw via Datatracker wrote:
Roman Danyliw has entered the following ballot position for draft-ietf-uta-rfc6125bis-14: No Objection
---------------------------------------------------------------------- COMMENT: ---------------------------------------------------------------------- Thank you to Derrell Piper for the SECDIR review. Thank you for this critical maintenance to RFC6125. ** Section 5. If the certificate will be used for only a single type of application service, the service provider SHOULD request a certificate that includes DNS-ID or IP-ID values that identify that service or, if appropriate for the application service type, SRV-ID or URI-ID values that limit the deployment scope of the certificate to only the defined application service type. Given the scope of the document being restricted to DNS-, IP-, SRV-, and URI-ID, what is the circumstances under which this “SHOULD” guidance would NOT be followed?
I can imagine several practical constraints that might limit the ability of the service provider to request a more tightly-scoped ID type, e.g., the SRV-ID type might not be supported by the service provider's preferred CA or by tooling used to generate certificate requests.
It's also possible that, even if service provider's tooling and its preferred CA support a more tightly scoped ID-type, the service provider wishes to include both the more tightly-scoped ID type *and* a less tightly-scoped ID type (e.g., DNS-ID) in order to maximize interoperability.
I think we can address this by adding text along those lines; here is a proposal:
If the certificate will be used for only a single type of application service, then the service provider SHOULD request a certificate whose deployment scope is limited only to that application service type (i.e., by means of an SRV-ID or URI-ID); this applies if the relevant protocol has defined such an ID type and if the service provider and CA both support the more tightly-scoped ID type. However, in the interest of wider interoperability, even when requesting a certificate that includes an SRV-ID or URI-ID, the service provider MAY also request that the certificate will include either a DNS-ID or IP-ID. Do you think that is more accurate?
If a service provider offers multiple application service types and wishes to limit the applicability of certificates using SRV-IDs or URI-IDs, they SHOULD request multiple certificates, rather than a single certificate containing multiple SRV-IDs or URI-IDs each identifying a different application service type. The SHOULD in this text implies there is an alternative to requesting multiple certificates? What is that?
The alternative is mentioned in the very next clause: "a single certificate containing multiple SRV-IDs or URI-IDs each identifying a different application service type."
Suggestions are welcome on how to make that clearer.
** Section 6.1.1 * If a server for the application service type is typically associated with a URI for security purposes (i.e., a formal protocol document specifies the use of URIs in server certificates), then the reference identifier SHOULD be a URI-ID. I appreciate that this is unchanged language from RFC6125. If the application service is using a URI, under what circumstances would the reference identifier NOT be a URI-ID?
This is the same situation as the first paragraph you mentioned. We should probably refer back to the modified text above so that we don't define the behavior in two places.
** Section 6.2 The search succeeds if any presented identifier matches one of the reference identifiers, at which point the client SHOULD stop the search. What is the standardized behavior if the client keeps looking after the first match (i.e., it is a SHOULD, not a MUST to stop)?
I don't think we need to define standardized behavior here because this belongs to the realm of implementation; thus we could route around this confusion by changing the text to:
The search succeeds if any presented identifier matches one of the reference identifiers, at which point there is no need for the client to continue the search.
** From idnits: == Outdated reference: draft-ietf-tls-subcerts has been published as RFC 9345
Good to know. Thanks again, Peter _______________________________________________ Uta mailing list Uta@ietf.org https://www.ietf.org/mailman/listinfo/uta