Re: [TLS] SCSV vs RI when both specified. Was: Updated draft
Martin Rex <mrex@sap.com> Tue, 12 January 2010 16:40 UTC
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From: Martin Rex <mrex@sap.com>
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To: DPKemp@missi.ncsc.mil
Date: Tue, 12 Jan 2010 17:40:39 +0100
In-Reply-To: <201001121543.o0CFhYuI011143@stingray.missi.ncsc.mil> from "Kemp, David P." at Jan 12, 10 10:43:33 am
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Cc: tls@ietf.org
Subject: Re: [TLS] SCSV vs RI when both specified. Was: Updated draft
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Kemp, David P. wrote: > > Perhaps I misunderstand the issue, but if there is absolutely no > known security problem in the absence of C->S signaling (ClientHello > contains neither SCSV nor empty RI), then it would seem that > C->S signaling is superfluous and should have been omitted from > the renego spec. I inferred from its existence that it served > some useful purpose. We need the C->S signaling in order to allow the S->C signaling, because the originial SSL&TLS protocols do not provide sufficient slack for S->C signaling without prior C->S signaling. Technically a S->C signaling for the initial handshake would be sufficient to prevent an updated client from having a client perform an old renegotiation with an updated server. Doing it both ways makes it more robust, and provides additional room for policy decisions. > > That is not a policy decision embedded in protocol, it is a > truth in advertising requirement. If a client's or server's > policy is that communication is more important than resistance > to renegotiation attack, than that policy is expressed by accepting > connections using the SSLv3, TLSv1.0, TLSv1.1, and TLSv1.2 > protocols. A TLS client or TLS server that does _not_ interoperate with an old TLS implementation on the initial handshake is simply not compliant to whatever protocol (SSLv3, TLSv1.0, TLSv1.1 or TLSv1.2) is negotiated. The new specification about (secure) TLS renegotiation _only_ deprecates an optional feature of the existing protocol and adds a new optional feature for them. This spec does _NOT_ change the core protocol. Otherwise it would not be an update, but a new protocol. -Martin
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Michael D'Errico
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Michael D'Errico
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Steve Checkoway
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Steve Checkoway
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Steve Checkoway
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Pasi.Eronen
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Yoav Nir
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Michael D'Errico
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Dr Stephen Henson
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Michael D'Errico
- Re: [TLS] SCSV vs RI when both specified - consen… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified - consen… Nasko Oskov
- Re: [TLS] SCSV vs RI when both specified - consen… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified - consen… Michael D'Errico
- Re: [TLS] SCSV vs RI when both specified - consen… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Yoav Nir
- Re: [TLS] SCSV vs RI when both specified - consen… Yoav Nir
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Kemp, David P.
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Ben Laurie
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Kemp, David P.
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Blumenthal, Uri - 0662 - MITLL
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Steve Dispensa
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Kemp, David P.
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Kemp, David P.
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Martin Rex
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Marsh Ray
- Re: [TLS] SCSV vs RI when both specified. Was: Up… Kyle Hamilton