Subject: [TLS] TLS 1.3 ServerConfiguration

From: Ilari Liusvaara <[email-masked]>
Date: Mon, 7 Dec 2015 13:09:48 +0200

This came up while writing serializers/deserializers for various TLS
1.2 and 1.3 stuff... Didn't see issues/pull requests for any of
these...

1) ServerConfiguration has field early_data_type, which is of type
EarlyDataType. I don't see definition of that type anywhere. I
guess it was missed when that type was removed?

2) If ServerConfiguration contains an unknown extension, how should
the client behave? Ignore the unknown extension, ignore the entiere
ServerConfiguration or send a fatal alert?

3) Could the group and server_key fields be combined into a single
field of type KeyShareEntry? The layout would be identical, and
one could clearly reuse KeyShareEntry parsing (especially
considering some groups have 2-byte interrior length fields
as opposed to 1-byte).

BTW: The new TLS 1.3 extensions don't have even test values
assigned. The values I put in were:
- early_data: 13000 (0x32C8)
- pre_shared_key: 13001 (0x32C9)
- key_share: 13002 (0x32CA)
- cookie: 13003 (0x32CB)

-Ilari

---

From: Eric Rescorla <[email-masked]>
Date: Mon, 7 Dec 2015 05:36:22 -0800

> guess it was missed when that type was removed?

Oops. This got removed. Will re-add.

> ServerConfiguration or send a fatal alert?

Ignore the unknown extension seems consistent.

> one could clearly reuse KeyShareEntry parsing

This is a great idea. I will do it!

> (especially

I noticed this in my implementation as well. I actually propose to just
remove that extra interior length field. Can't see any reason to keep
it.

- cookie: 13003 (0x32CB)

I suggest 40-44 in the order you list above, since we've agreed not to have
specified ranges any more.

-Ekr

>
>
> -Ilari
>
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