[TLS] ECH shared/split MUST abort statements

[Stephen Farrell]

Hiya,

It looks like the following text was added in draft-18:

"
   In split mode, a client-facing server which receives a ClientHello
   with ECHClientHello.type of inner MUST abort with an
   "illegal_parameter" alert.  Similarly, in split mode, a backend
   server which receives a ClientHello with ECHClientHello.type of outer
   MUST abort with an "illegal_parameter" alert.

   In shared mode, a server plays both roles, first decrypting the
   ClientHelloOuter and then using the contents of the ClientHelloInner.
   A shared mode server which receives a ClientHello with
   ECHClientHello.type of inner MUST abort with an "illegal_parameter"
   alert, because such a ClientHello should never be received directly
   from the network.
"

That's not something I included in the implementation I'm trying to
upstream to OpenSSL.

Two questions:

a) does someone recall why these "MUST abort" statements are needed?

b) have we really got this right? ISTM server code may be processing
both inner or outer ClientHello messages and forcing the kinds of
distinction envisaged above might be unwieldy

Thanks,
S.

OpenPGP_signature.asc
Description: OpenPGP digital signature

_______________________________________________
TLS mailing list -- tls@ietf.org
To unsubscribe send an email to tls-le...@ietf.org