Re: [CHANNEL-BINDING] [TLS] New Problem (Was: Last Call: draft-altman-tls-channel-bindings)
Larry Zhu <larry.zhu@microsoft.com> Thu, 05 November 2009 00:03 UTC
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From: Larry Zhu <larry.zhu@microsoft.com>
To: Nicolas Williams <Nicolas.Williams@sun.com>
Thread-Topic: [TLS] New Problem (Was: Last Call: draft-altman-tls-channel-bindings)
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Date: Thu, 05 Nov 2009 00:03:41 +0000
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Cc: "channel-binding@ietf.org" <channel-binding@ietf.org>, "tls@ietf.org" <tls@ietf.org>, "sasl@ietf.org" <sasl@ietf.org>
Subject: Re: [CHANNEL-BINDING] [TLS] New Problem (Was: Last Call: draft-altman-tls-channel-bindings)
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I think this is good as is. The mentioned issue is in the TLS itself at which layer it knows every well what a TLS connection is so we do not have any confusions related to I mentioned. Now some comments on the alternative proposals, I would prefer a stable identifier for the channel. If the name of the channel constantly changes when TLS renegotiates, it is a bad taste in the mouth for me. -----Original Message----- From: tls-bounces@ietf.org [mailto:tls-bounces@ietf.org] On Behalf Of Nicolas Williams Sent: Wednesday, November 04, 2009 2:48 PM To: Larry Zhu Cc: channel-binding@ietf.org; tls@ietf.org; sasl@ietf.org Subject: [TLS] New Problem (Was: Last Call: draft-altman-tls-channel-bindings) On Wed, Nov 04, 2009 at 10:13:46PM +0000, Larry Zhu wrote: > The proposed looks fine. Thanks, Thanks. HOWEVER, Martin's post to the TLS WG list about MITM attacks in re-negotiations is relevant. Re-negotiations have no real binding between inner and outer connections. Clients can enforce that the server end-point is the same (has the same certificate, whatever) for both connections: inner and outer. Servers can also force the inner connection to change cipher specs. But suppose that the outer connection used an TLS_DH_anon_* cipher suite! Then there is no binding whatsoever between the inner and outer connection. And then we have a real problem for tls-unique. We need at least a security considerations note about this. But we should also consider changing tls-unique to be the client's Finished message for the _inner-most_ TLS connection, not outer-most. (Outer-most is OK IFF there's a binding between each channel.) Comments? Nico -- _______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
- Re: [CHANNEL-BINDING] RESOLVED (Re: [sasl] lasgt … Nicolas Williams
- [CHANNEL-BINDING] Last Call: draft-altman-tls-cha… The IESG
- Re: [CHANNEL-BINDING] Last Call: draft-altman-tls… Simon Josefsson
- Re: [CHANNEL-BINDING] Last Call: draft-altman-tls… Nicolas Williams
- [CHANNEL-BINDING] Unrelated (Re: [TLS] RESOLVED (… Nicolas Williams
- Re: [CHANNEL-BINDING] [sasl] lasgt call comments … Pasi.Eronen
- Re: [CHANNEL-BINDING] lasgt call comments (st Cal… Simon Josefsson
- Re: [CHANNEL-BINDING] lasgt call comments (st Cal… Simon Josefsson
- Re: [CHANNEL-BINDING] [sasl] lasgt call comments … Nicolas Williams
- [CHANNEL-BINDING] lasgt call comments (st Call: d… Larry Zhu
- Re: [CHANNEL-BINDING] lasgt call comments (st Cal… Larry Zhu
- Re: [CHANNEL-BINDING] [TLS] [sasl] lasgt call com… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] [sasl] lasgt call com… Larry Zhu
- Re: [CHANNEL-BINDING] [TLS] [sasl] lasgt call com… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [CHANNEL-BINDING] [sasl] lasgt call comments … Larry Zhu
- Re: [CHANNEL-BINDING] [TLS] [sasl] lasgt call com… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] [sasl] lasgt call com… Martin Rex
- [CHANNEL-BINDING] RESOLVED (Re: [sasl] lasgt call… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Martin Rex
- Re: [CHANNEL-BINDING] RESOLVED (Re: [sasl] lasgt … Simon Josefsson
- Re: [CHANNEL-BINDING] RESOLVED (Re: [sasl] lasgt … Martin Rex
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Martin Rex
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Martin Rex
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Peter Gutmann
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [CHANNEL-BINDING] Unrelated (Re: [TLS] RESOLV… Martin Rex
- Re: [CHANNEL-BINDING] Unrelated (Re: [TLS] RESOLV… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Martin Rex
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Pasi.Eronen
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Pasi.Eronen
- Re: [CHANNEL-BINDING] [TLS] lasgt call comments (… Pasi.Eronen
- Re: [CHANNEL-BINDING] [TLS] lasgt call comments (… Simon Josefsson
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [CHANNEL-BINDING] [sasl] [TLS] lasgt call com… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Jeffrey Hutzelman
- Re: [CHANNEL-BINDING] [sasl] [TLS] lasgt call com… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Michael D'Errico
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Sam Hartman
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] lasgt call comments (… Simon Josefsson
- Re: [CHANNEL-BINDING] [TLS] lasgt call comments (… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] RESOLVED (Re: [sasl] … Larry Zhu
- [CHANNEL-BINDING] New Problem (Was: Last Call: dr… Nicolas Williams
- Re: [CHANNEL-BINDING] [TLS] New Problem (Was: Las… Larry Zhu
- Re: [CHANNEL-BINDING] [TLS] New Problem (Was: Las… Nicolas Williams