Re: [TLS] [Emu] Fwd: Benjamin Kaduk's Discuss on draft-ietf-emu-eap-tls13-13: (with DISCUSS and COMMENT)

[Joseph Salowey <[e-mail]>]

On Mon, Feb 1, 2021 at 11:55 AM Alan DeKok <[e-mail]>
wrote:

> On Feb 1, 2021, at 2:32 PM, Joseph Salowey <[e-mail]> wrote:
> >
> >
> >
> > On Mon, Feb 1, 2021 at 11:25 AM Alan DeKok <[e-mail]>
> wrote:
> > On Feb 1, 2021, at 11:26 AM, Eric Rescorla <[e-mail]> wrote:
> > > Yes, this is what I have in mind. So, maybe there's never any need for
> the server to say "I won't say anything more" after just one round trip?
> >
> >   I think so, yes.
> >
> >   That means of course EAP-TLS will always require 4.5 round trips.
> >
> > [Joe] I don't follow why this means 4.5 round trips would be required.
>
>   If the CloseNotify signal is sent by the server *after* it receives the
> client certs, then another round trip is required.  At least, according to
> Figure 1 of draft-13.
>
>   The CloseNotify can't be sent with the EAP-Success, because the
> EAP-Success can't carry data.  So the packet flow looks something like this:
>
>
[Joe] What purpose is the CloseNotify serving? RFC 5216 does not require
CloseNotify.


>    EAP-TLS Peer                                      EAP-TLS Server
>
>                                                         EAP-Request/
>                                 <--------                  Identity
>    EAP-Response/
>    Identity (Privacy-Friendly)  -------->
>                                                         EAP-Request/
>                                                    EAP-Type=EAP-TLS
>                                 <--------                (TLS Start)
>    EAP-Response/
>    EAP-Type=EAP-TLS
>   (TLS ClientHello)             -------->
>                                                         EAP-Request/
>                                                    EAP-Type=EAP-TLS
>                                                    (TLS ServerHello,
>                                             TLS EncryptedExtensions,
>                                              TLS CertificateRequest,
>                                                     TLS Certificate,
>                                               TLS CertificateVerify,
>                                 <-------            TLS Finished)
>    EAP-Response/
>    EAP-Type=EAP-TLS
>   (TLS Certificate,
>    TLS CertificateVerify,
>    TLS Finished)                -------->
>
>                                                             EAP-Request/
>                                                    EAP-Type=EAP-TLS
>                             <--------        (TLS CloseNotify)
>
>    EAP-Response/
>    EAP-Type=EAP-TLS
>     (TLS Ack)                 -------->
>                                 <--------               EAP-Success