Re: Review of draft-saintandre-tls-server-id-check
Peter Saint-Andre <stpeter@stpeter.im> Mon, 13 September 2010 16:07 UTC
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Date: Mon, 13 Sep 2010 10:08:11 -0600
From: Peter Saint-Andre <stpeter@stpeter.im>
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To: Shumon Huque <shuque@isc.upenn.edu>
Subject: Re: Review of draft-saintandre-tls-server-id-check
References: <20100908195349.GA4292@isc.upenn.edu> <C8ADC7ED.EBA4%stefan@aaa-sec.com> <20100909182253.GB3460@isc.upenn.edu>
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Cc: Bernard Aboba <bernard_aboba@hotmail.com>, IETF cert-based identity <certid@ietf.org>, ietf@ietf.org
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On 9/9/10 12:22 PM, Shumon Huque wrote: > On Wed, Sep 08, 2010 at 11:08:29PM +0200, Stefan Santesson wrote: >> >> On 10-09-08 9:53 PM, "Shumon Huque" <shuque@isc.upenn.edu> wrote: >>> The output of the SRV record lookup contains a target hostname, >>> not a service name, so it's not applicable to the SRVName name >>> form. The target could be used in another name form (dNSName) >>> as the reference identifier, but then the client needs to convince >>> itself that the lookup was done securely (DNSSEC or some other >>> means) otherwise there's a security problem. >> >> I disagree, >> >> A client can use the output from the DNS lookup also from a normal insecure >> DNS server. >> >> The only thing the client need to do is to verify that the domain name >> provided in the input to the lookup matches the host names provided in the >> output. It can then safely use the host names in the SRV record as reference >> identifiers IF the SRV-ID in the server certificate matches the the >> reference identifier. > > This only works if the certificate matching rules say something > like "match the SRVName AND also match the DNS resolved target > hostname in dNSName". If a client attempts to match _only_ the DNS > resolved hostname without DNSSEC, there is a security problem. > > The question is: what should the certificate matching rules say > when encountering a certificate with multiple identity types? > Right now the draft approximately says "find a match" (ie. find > ANY match), rather than match some logically AND'ed combination of > identity types. > > http://tools.ietf.org/html/draft-saintandre-tls-server-id-check-09#section-4 Hi Shumon, As I see it, this I-D is attempting to capture best current practices regarding the issuance and checking of certificates containing application server identities. Do we have evidence that any existing certification authorities issue certificates containing both an SRVname for the source domain (e.g., example.com) and dNSName for the target domain (e.g., apphosting.example.net)? Do we have evidence that any existing application clients perform such checks? If not, I would consider such complications to be out of scope for this I-D. That said, we need to be aware that if such usage arises in the future, someone might write a document that updates or obsoletes this I-D; in fact the present authors very much expect that such documents will emerge after the Internet community (specifically certification authorities, application service providers, and application client developers) have gained more experience with PKIX certificates in the context of various application technologies. Peter -- Peter Saint-Andre https://stpeter.im/
- Review of draft-saintandre-tls-server-id-check Bernard Aboba
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- RE: Review of draft-saintandre-tls-server-id-check Bernard Aboba
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check =JeffH
- Re: Review of draft-saintandre-tls-server-id-check t.petch
- RE: Review of draft-saintandre-tls-server-id-check Bernard Aboba
- Re: [xmpp] Review of draft-saintandre-tls-server-… Bernard Aboba
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check t.petch
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- RE: Review of draft-saintandre-tls-server-id-check Bernard Aboba
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Shumon Huque
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- RE: Review of draft-saintandre-tls-server-id-check Bernard Aboba
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: [certid] Review of draft-saintandre-tls-serve… Shumon Huque
- Re: Review of draft-saintandre-tls-server-id-check Shumon Huque
- Re: [certid] Review of draft-saintandre-tls-serve… Shumon Huque
- Re: [certid] Review of draft-saintandre-tls-serve… Stefan Santesson
- Re: [certid] Review of draft-saintandre-tls-serve… Stefan Santesson
- Re: [certid] Review of draft-saintandre-tls-serve… Shumon Huque
- Re: [certid] Review of draft-saintandre-tls-serve… Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Martin Rex
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: [certid] Review of draft-saintandre-tls-serve… Paul Hoffman
- Re: [certid] Review of draft-saintandre-tls-serve… Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Shumon Huque
- Re: [certid] Review of draft-saintandre-tls-serve… Richard L. Barnes
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: [certid] Review of draft-saintandre-tls-serve… Shumon Huque
- Re: Review of draft-saintandre-tls-server-id-check Dave Cridland
- Re: [certid] Review of draft-saintandre-tls-serve… Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: [certid] Review of draft-saintandre-tls-serve… Peter Saint-Andre
- Re: [certid] Review of draft-saintandre-tls-serve… Dave Cridland
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Dave Cridland
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Dave Cridland
- Re: Review of draft-saintandre-tls-server-id-check Stefan Santesson
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Dave Cridland
- Re: [certid] Review of draft-saintandre-tls-serve… Shumon Huque
- Re: [certid] Review of draft-saintandre-tls-serve… Dave Cridland
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check t.petch
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Re: Review of draft-saintandre-tls-server-id-check Peter Saint-Andre
- Why require EKU for certid? Paul Hoffman
- Re: Why require EKU for certid? Peter Saint-Andre
- Re: [certid] Why require EKU for certid? Martin Rex
- RE: [TLS] Why require EKU for certid? Jim Schaad
- Re: [certid] Why require EKU for certid? Henry B. Hotz