Re: [TLS] lasgt call comments (st Call: draft-altman-tls-channel-bindings (Channel Bindings for TLS) to Proposed Standard)
Simon Josefsson <simon@josefsson.org> Wed, 28 October 2009 14:23 UTC
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From: Simon Josefsson <simon@josefsson.org>
To: Larry Zhu <larry.zhu@microsoft.com>
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Date: Wed, 28 Oct 2009 15:24:09 +0100
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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: [TLS] lasgt call comments (st Call: draft-altman-tls-channel-bindings (Channel Bindings for TLS) to Proposed Standard)
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Simon Josefsson <simon@josefsson.org> writes: > http://josefsson.org/sasl-gs2/draft-josefsson-sasl-tls-cb-02.txt > > It makes sure to bind the channel binding uniquely to BOTH the current > connection and the current session. The > draft-altman-tls-channel-bindings-07 document only binds to the current > TLS connection. So from this perspective, my work has the same issue, > but it is different in other aspects. This reminded me of an earlier observation, and it might be relevant to re-iterate it here. Consider this: Day 1: 1. Client establish TLS anon-anon to server. 2. User authenticates using SCRAM with channel binding to the TLS channel 3. User/client disconnects Day 2: 4. Client resumes the TLS anon-anon connection 5. Client rehandshake with X.509 client + server authentication 6. User authenticates using SCRAM with channel binding to the TLS channel 7. User/client disconnects Day 3: 7. Client resumes the TLS session 8. Client rehandshake it as anon-anon 9. User authenticates using SCRAM with channel binding to the TLS channel 10. User/client disconnects With draft-altman-tls-channel-bindings-07, the channel binding data used in all three SCRAM authentications is the same bit sequence. That means there is only an indirect cryptographic binding between the SCRAM user authentication and the X.509 client authentication. /Simon
- [TLS] Last Call: draft-altman-tls-channel-binding… The IESG
- Re: [TLS] lasgt call comments (st Call: draft-alt… Larry Zhu
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Pasi.Eronen
- Re: [TLS] lasgt call comments (st Call: draft-alt… Simon Josefsson
- Re: [TLS] lasgt call comments (st Call: draft-alt… Simon Josefsson
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Nicolas Williams
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Nicolas Williams
- Re: [TLS] [sasl] lasgt call comments (st Call: Martin Rex
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Larry Zhu
- Re: [TLS] [sasl] lasgt call comments (st Call: Nicolas Williams
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Larry Zhu
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Nicolas Williams
- [TLS] RESOLVED (Re: [sasl] lasgt call comments (s… Nicolas Williams
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Martin Rex
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Simon Josefsson
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Martin Rex
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Martin Rex
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Peter Gutmann
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Martin Rex
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Nicolas Williams
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Nicolas Williams
- [TLS] Unrelated (Re: [CHANNEL-BINDING] RESOLVED (… Nicolas Williams
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [TLS] Unrelated (Re: [CHANNEL-BINDING] RESOLV… Martin Rex
- Re: [TLS] [CHANNEL-BINDING] Unrelated (Re: RESOLV… Nicolas Williams
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Martin Rex
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Martin Rex
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Pasi.Eronen
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Pasi.Eronen
- Re: [TLS] lasgt call comments (st Call: draft-alt… Pasi.Eronen
- Re: [TLS] lasgt call comments (st Call: draft-alt… Simon Josefsson
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Nicolas Williams
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Nicolas Williams
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Michael D'Errico
- Re: [TLS] [sasl] lasgt call comments (st Call: dr… Nicolas Williams
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Nicolas Williams
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Jeffrey Hutzelman
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Sam Hartman
- Re: [TLS] [CHANNEL-BINDING] RESOLVED (Re: [sasl] … Nicolas Williams
- Re: [TLS] lasgt call comments (st Call: draft-alt… Simon Josefsson
- Re: [TLS] lasgt call comments (st Call: draft-alt… Nicolas Williams
- Re: [TLS] RESOLVED (Re: [sasl] lasgt call comment… Larry Zhu
- [TLS] New Problem (Was: Last Call: draft-altman-t… Nicolas Williams
- Re: [TLS] New Problem (Was: Last Call: draft-altm… Larry Zhu
- Re: [TLS] [CHANNEL-BINDING] New Problem (Was: Las… Nicolas Williams