Internet DRAFT - draft-hildebrand-xmpp-dnssec
draft-hildebrand-xmpp-dnssec
Network Working Group J. Hildebrand
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track March 7, 2011
Expires: September 8, 2011
DNSSEC for XMPP SRV Records
draft-hildebrand-xmpp-dnssec-00.txt
Abstract
This document proposes that DNS SRV records that can be trusted via
DNSSEC signatures may be used to generate a list of acceptable names
to check on server certificates offered by TLS.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions Used In This Document . . . . . . . . . . . . . . . 3
3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Dialback considerations . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . . 4
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 5
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1. Introduction
XMPP uses SRV records for clients and servers to find servers for a
given domain. Today, since the SRV record cannot be trusted, the
server has to offer a TLS certificate that matches the original
domain name, rather than one for the hostname in the SRV record.
Deployment of delegated hosts would be much easier if the host could
offer a certificate with the host name, rather than having to offer a
certificate with the original domain name.
This document proposes that the server may offer a cert with any of
the names generated from looking up trusted DNS entries.
Note: this document is only intended as a placeholder; it will be
dramatically expanded later. As well it is likely that this approach
is useful for protocols other than XMPP.
2. Conventions Used In This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
3. Overview
The following steps are followed by a provider hosting "example.com"
on the server "host1.example.net":
1. The owner of "example.com" serves an SRV record for "_xmpp-
server._tcp.example.com" and "_xmpp-client._tcp.example.com", for
example "0 1 5269 host1.example.net." might be used for each.
2. The owner of "example.com" MUST ensure that "example.com" is
signed using DNSSEC [RFC4035], and that the SRV record is also
signed using DNSSEC.
3. The hosting provider at "host1.example.net" generates a [RFC5280]
PKIX certificate and has it signed by a widely-trusted
Certificate Authority.
4. The hosting provider offers the generated certificate to anyone
who connects and wants to talk to "example.com".
The following steps are followed by an initiating entity connecting
to "example.com":
1. The initiator starts with an empty name list L.
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2. The initiator adds the original domain name ("example.com" here)
to L
3. The initiator does the normal SRV lookup, asking its resolver for
DNSEC trust information.
4. For each hostname, CNAME, A or AAAA record that the initiator
finds which is fully trustable according to DNSSEC, that name or
IP address is added to L.
5. The initiator connects to the server as specified in XMPP
[I-D.ietf-xmpp-3920bis], specifying "example.com" in the stream
to attribute. Other protocols might use SNI [RFC4366] to
indicate the desired host name.
6. The initiator MUST check each name in L against the certificate
offered by the responder, using the rules specified in section
13.7.2 of [I-D.ietf-xmpp-3920bis] (or the equivalent rules for
the target protocol).
4. Dialback considerations
TODO: how to share connections
TODO: interactions with dialback piggybacking
5. IANA Considerations
[TODO]
6. Security Considerations
Much more to follow here.
7. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4035] Arends, R., Austein, R., Larson, M., Massey, D., and S.
Rose, "Protocol Modifications for the DNS Security
Extensions", RFC 4035, March 2005.
[RFC4366] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J.,
and T. Wright, "Transport Layer Security (TLS)
Extensions", RFC 4366, April 2006.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
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Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, May 2008.
[I-D.ietf-xmpp-3920bis]
Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Core", draft-ietf-xmpp-3920bis-22 (work
in progress), December 2010.
Appendix A. Acknowledgments
[TODO]
Author's Address
Joe Hildebrand
Cisco Systems, Inc.
1899 Wyknoop Street, Suite 600
Denver, CO 80202
USA
Email: jhildebr@cisco.com
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