[TLS] Protocol version for inappropriate_fallback alerts (was: Re: I-D Action: draft-ietf-tls-downgrade-scsv-01.txt)

Florian Weimer <fweimer@redhat.com> Tue, 11 November 2014 13:44 UTC

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Date: Tue, 11 Nov 2014 14:44:22 +0100
From: Florian Weimer <fweimer@redhat.com>
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Subject: [TLS] Protocol version for inappropriate_fallback alerts (was: Re: I-D Action: draft-ietf-tls-downgrade-scsv-01.txt)
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On 11/10/2014 09:07 PM, internet-drafts@ietf.org wrote:
>          Title           : TLS Fallback Signaling Cipher Suite Value (SCSV) for Preventing Protocol Downgrade Attacks
>          Authors         : Bodo Moeller
>                            Adam Langley
> 	Filename        : draft-ietf-tls-downgrade-scsv-01.txt
> 	Pages           : 8
> 	Date            : 2014-11-10

Section 3 still does not mention which version to put into the 
inappropriate_fallback alert message.  For interoperability reasons, the 
TLS version from ClientHello.client_version has to be used (even if the 
version negotiation has not been completed because the server might opt 
to bail out early out of the handshake code).

Florian Weimer / Red Hat Product Security