Re: [TLS] SCSV vs RI when both specified - consensus?

Marsh Ray <marsh@extendedsubset.com> Mon, 21 December 2009 18:02 UTC

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Date: Mon, 21 Dec 2009 12:01:50 -0600
From: Marsh Ray <marsh@extendedsubset.com>
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To: Michael D'Errico <mike-list@pobox.com>
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Subject: Re: [TLS] SCSV vs RI when both specified - consensus?
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Michael D'Errico wrote:
> I agree we need to publish ASAP, but if consensus is (1), then I need
> to change my (running) code since it currently does (2).


Is everybody OK with this wording? (it's the more lenient choice):

> Clients MUST NOT put multiple occurrences of an RI extension in the
> same Client Hello message. A client MAY specify the SCSV in the same
> Client Hello message as an RI extension (the SCSV will be effectively
> ignored).
>
> A server receiving a Client Hello containing multiple RI extensions
> MUST generate a fatal "decode_error" alert and terminate the
> connection. A server receiving a Client Hello containing the SCSV
> and an RI extension is to interpret the RI as usual and ignore the
> SCSV.

We'll have to fix the conflict with the current:
> This SCSV is not a true cipher suite and cannot be negotiated. It
> merely has exactly the same semantics as an empty "renegotiation_info"
> extension.

to something like:
> This SCSV is not a true cipher suite and cannot be negotiated, it
> has similar semantics as an empty "renegotiation_info" extension.

- Marsh