Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (Transport Layer
Simon Josefsson <simon@josefsson.org> Thu, 01 October 2009 16:48 UTC
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From: Simon Josefsson <simon@josefsson.org>
To: "Joseph Salowey (jsalowey)" <jsalowey@cisco.com>
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Date: Thu, 01 Oct 2009 18:49:32 +0200
In-Reply-To: <AC1CFD94F59A264488DC2BEC3E890DE508D3C853@xmb-sjc-225.amer.cisco.com> (Joseph Salowey's message of "Thu, 1 Oct 2009 09:17:02 -0700")
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Cc: tls@ietf.org
Subject: Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (Transport Layer
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"Joseph Salowey (jsalowey)" <jsalowey@cisco.com> writes: > I don't think option 1 is an appropriate change for this document, > although I could be convinced otherwise because I don't think the SHOULD > is very enlightening. > > For option 2 I would prefer text that explains the SHOULD, maybe > something like: > > "Since it is possible for a client to present a different server_name in > the application protocol, application server implementations that rely > upon these names being the same MUST check to make sure the client did > not present a different name in the application protocol." I believe that would resolve my concern. Thanks, /Simon > Joe > >> -----Original Message----- >> From: tls-bounces@ietf.org [mailto:tls-bounces@ietf.org] On >> Behalf Of Blumenthal, Uri >> Sent: Thursday, October 01, 2009 4:44 AM >> To: 'simon@josefsson.org'; 'martin.rex@sap.com' >> Cc: 'tls@ietf.org' >> Subject: Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis >> (Transport Layer >> >> I support option (2) and am against option(1), for reasons >> expressed in earlier emails. >> >> Tnx! >> >> >> ----- Original Message ----- >> From: Simon Josefsson <simon@josefsson.org> >> To: martin.rex@sap.com <martin.rex@sap.com> >> Cc: Blumenthal, Uri; tls@ietf.org <tls@ietf.org> >> Sent: Thu Oct 01 07:00:34 2009 >> Subject: Re: Last Call: draft-ietf-tls-rfc4366-bis (Transport Layer >> >> Martin Rex <Martin.Rex@sap.com> writes: >> >> > Blumenthal, Uri wrote: >> >> >> >> In my understanding, TLS-established server_name should be >> enforced >> >> by the server. >> >> >> >> And Martin - I couldn't disagree more with you. The whole point of >> >> using TLS is to enforce who can access what. So the client >> makes sure >> >> he accesses the right server, the server makes sure he >> grants access >> >> to the right pages on the right virtual host. And if your server >> >> doesn't do that - please kindly tell me what commercial or >> freeware >> >> product it is included in, so I can avoid buying or using >> it in the >> >> future. >> > >> > There seems to be a significant misunderstanding. >> > >> > The Host header field of an HTTP request is a detail of an >> application >> > protocol. The hostname conveyed by the TLS extension server name >> > indication (SNI) happens at a competely different protocol layer. >> > >> > The difference becomes obvious when you add reverse proxies >> into the >> > picture (those which terminate the TLS wrapping). >> > >> > Conceptually, the Host: header field of a HTTP request is >> part of the >> > URL. If a reverse proxy perform URL rewriting, it may as >> well have to >> > rewrite Host: header fields. That depends entirely on the backend >> > architecture of each particular software installation. >> > >> > >> > Whether or not an application may want to make consistency checks >> > between a Host: Header field and a hostname received via SNI at the >> > specific point of the backend architecture where TLS was terminated >> > depends entirely on the backend architecture, and is an application >> > issue. >> >> I believe this wording in RFC 4366bis makes it a TLS issue: >> >> If the server_name is established in the TLS session handshake, the >> client SHOULD NOT attempt to request a different server name at the >> application layer. >> >> I believe there are two options: >> >> 1) Either remove all requirements on application behaviour >> from 4366bis >> (including the text above) and explicitly defer such discussions to >> other documents. >> >> 2) Add the text I proposed to make servers actually validate proper >> client behaviour. >> >> I went for 2) assuming that the text above was intentional, >> but I share your arguments for going with approach 1). >> >> /Simon >> _______________________________________________ >> TLS mailing list >> TLS@ietf.org >> https://www.ietf.org/mailman/listinfo/tls >>
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Blumenthal, Uri
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Blumenthal, Uri
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Martin Rex
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Simon Josefsson
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Joseph Salowey (jsalowey)
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Peter Saint-Andre
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Simon Josefsson
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Blumenthal, Uri
- Re: [TLS] Last Call: draft-ietf-tls-rfc4366-bis (… Martin Rex