Subject: [TLS] RFC8446 Fig3

From: Daniel Migault <[email-masked]>
Date: Thu, 2 May 2019 20:30:04 -0400

Hi,

This might have already been mentioned on the list, but unless I
misinterpreter something it seems to me that the second handshake of figure
3 is missing psk_key_exchange_modes extension.

Yours,
Daniel

 Figure 3 shows a pair of handshakes in which the first handshake
   establishes a PSK and the second handshake uses it:

          Client                                               Server

   Initial Handshake:
          ClientHello
          + key_share               -------->
                                                          ServerHello
                                                          + key_share
                                                {EncryptedExtensions}
                                                {CertificateRequest*}
                                                       {Certificate*}
                                                 {CertificateVerify*}
                                                           {Finished}
                                    <--------     [Application Data*]
          {Certificate*}
          {CertificateVerify*}
          {Finished}                -------->
                                    <--------      [NewSessionTicket]
          [Application Data]        <------->      [Application Data]

   Subsequent Handshake:
          ClientHello
          + key_share*
          + pre_shared_key          -------->
                                                          ServerHello
                                                     + pre_shared_key
                                                         + key_share*
                                                {EncryptedExtensions}
                                                           {Finished}
                                    <--------     [Application Data*]
          {Finished}                -------->
          [Application Data]        <------->      [Application Data]

               Figure 3: Message Flow for Resumption and PSK

---

From: "Martin Thomson" <[email-masked]>
Date: Thu, 02 May 2019 20:47:21 -0400

That's right.  You might open an editorial erratum, which I would suggest be held for document update.

Note that there is no promise that the list of extensions is complete, as this doesn't show the supported_versions or signature_schemes extension either, but the omission is probably not great in this case, since the PSK modes  are highly relevant.

On Fri, May 3, 2019, at 10:30, Daniel Migault wrote:
> misinterpreter something it seems to me that the second handshake of 
> figure 3 is missing psk_key_exchange_modes extension. 
> 
> Yours, 
> Daniel
> 
> _______________________________________________
> TLS mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/tls
>

---

From: Daniel Migault <[email-masked]>
Date: Thu, 2 May 2019 21:05:54 -0400

thanks, I just submitted the erratum.
Yours,
Daniel

On Thu, May 2, 2019 at 8:48 PM Martin Thomson <[email-masked]> wrote:

> Note that there is no promise that the list of extensions is complete, as
> this doesn't show the supported_versions or signature_schemes extension
> either, but the omission is probably not great in this case, since the PSK
> modes  are highly relevant.
>