Hi, I would like to mention that TLS can be used with non-X.509 certificates also. In particular, it can be used with ITS ETSI and IEEE certificates. https://datatracker.ietf.org/doc/html/draft-serhrouchni-tls-certieee1609
So, in my opinion, TLS should be very loosely or not at all coupled with RFC 5280. Thanks and Regards, Sankalp Bagaria. > On Tue, May 16, 2017 at 11:31 AM, Russ Housley <hous...@vigilsec.com> > wrote: > > > > On May 16, 2017, at 11:23 AM, Eric Rescorla <e...@rtfm.com> wrote: > > > > > > > > On Tue, May 16, 2017 at 8:17 AM, Russ Housley <hous...@vigilsec.com> > wrote: > >> > >> > >> On May 15, 2017, at 7:01 PM, Eric Rescorla <e...@rtfm.com> wrote: > >> > >> > >> > >> On Mon, May 15, 2017 at 12:38 PM, Russ Housley <hous...@vigilsec.com> > >> wrote: > >>> > >>> Just commenting on Section 4.2 ? > >>> > >>> > > >>> > > 3. Section 4.2. > >>> > > > >>> > > "In general, detailed certificate validation procedures are out > of > >>> > > scope for TLS (see [RFC5280]). This section provides > TLS-specific > >>> > > requirements." > >>> > > > >>> > > I don't see an explanation of why it is out-of-scope. The > reference > >>> > > is just to RFC5280, which seems odd. I would expect the reference > to > >>> > > be to something that explains why it is out-of-scope. > >>> > >>> I think the the separation of certificate path validation from the TLS > >>> protocol is correct, but perhaps this can be explained differently. > Perhaps > >>> the approach should be that TLS depends upon certificate path > validation as > >>> described in RFC 5280. > >>> > >>> > In general, TLS's policy (dating back to TLS 1.0) has been that the > >>> > job of TLS is to carry the certificates and other authentication > >>> > material but to leave it up to other parts of the system to > >>> > interpret them. It's been a long time since that decision was made, > >>> > but from my perspective, there are a number of major reasons: > >>> > > >>> > 1. Most of PKI processing (path construction, etc.) is generic and > >>> > not specific to TLS. What is specific to TLS is: > >>> > > >>> > * How to indicate what your PKI capabilities are > >>> > (see, e.g, S 4.2.4 and 4.3.2) > >>> > * How to stuff the PKI material into the protocol > >>> > (principally S 4.4.2) > >>> > * How to determine whether a given certificate is suitable for > >>> > use in TLS 4.4.4.2 and 4.3.2.1). > >>> > > >>> > So we want to outsource the generic PKI part > >>> > > >>> > > >>> > 2. It matches the software architecture that people often use, > >>> > which is to have a TLS stack but separate PKI validation. For > >>> > instance, Firefox uses NSS for TLS but moz::pkix for > >>> > validation. Similarly, Chrome uses BoringSSL for TLS > >>> > but the system PKI libraries for validation. > >>> > > >>> > > >>> > In this case, I think that this text was more intended to > >>> > say "and go read 5280 to learn how to do this". To that end, > >>> > I suggest we say" > >>> > > >>> > > >>> > "In general detailed certificate validation procedures are out of > >>> > scope for TLS. [RFC5280] provides general procedures for > >>> > certificate validation. This section provides TLS-specific > >>> > requirements.? > >>> > >>> I agree with the reasoning, however the dependency on RFC 5280 should > be > >>> called out in a MUST statement. I suggest something like: > >>> > >>> "TLS depends on certificate path validation, and a conformant > >>> TLS implementation MUST implement certificate paths validation > >>> in a manner that achieves the same result as [RFC5280]. This > >>> section provides TLS-specific requirements.? > >>> > >>> Note that RFC 5280 is already a normative reference. > >> > >> > >> A MUST here would be a pretty material change to historical TLS > practice. > >> As Viktor says, there are TLS-using applications that just don't > validate > >> the cert via 5280 at all. > >> > >> > >> I think we want to say that if the certificates are used, then the > >> certification path MUST be validated in a manner that is compatible with > >> Internet X.509 certificate profile [RFC5280]; however, other approaches > to > >> validation of the public key, such as the DANE TLSA resource record > >> [RFC6698], are also acceptable. > > > > > > I can see how you would want to say that, but it's not really consistent > > either > > with historical practice or with the way that other standards track RFCs > use > > TLS > > with certificates (see RFC 5763). > > > > > > Actually, that is a great example. I accept the need for loose coupling. > > OK, does that put us back to the suggested wording: > > "TLS depends on certificate path validation, and a conformant > TLS implementation MUST implement certificate paths validation > in a manner that achieves the same result as [RFC5280]. This > section provides TLS-specific requirements.? > > For any developers following, does this help enough with any > interoperability questions? > > Thanks, > Kathleen > > > > > Russ > > > > > > -- > > Best regards, > Kathleen > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls > > > ------------------------------ > > End of TLS Digest, Vol 154, Issue 61 > ************************************ >
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