draft-ietf-uta-xmpp-03.txt   draft-ietf-uta-xmpp-04.txt 
Network Working Group P. Saint-Andre Network Working Group P. Saint-Andre
Internet-Draft &yet Internet-Draft &yet
Updates: 6120 (if approved) T. Alkemade Updates: 6120 (if approved) T. Alkemade
Intended status: Standards Track Intended status: Standards Track
Expires: May 15, 2015 November 11, 2014 Expires: May 30, 2015 November 26, 2014
Use of Transport Layer Security (TLS) in the Extensible Messaging and Use of Transport Layer Security (TLS) in the Extensible Messaging and
Presence Protocol (XMPP) Presence Protocol (XMPP)
draft-ietf-uta-xmpp-03 draft-ietf-uta-xmpp-04
Abstract Abstract
This document provides recommendations for the use of Transport Layer This document provides recommendations for the use of Transport Layer
Security (TLS) in the Extensible Messaging and Presence Protocol Security (TLS) in the Extensible Messaging and Presence Protocol
(XMPP). This document updates RFC 6120. (XMPP). This document updates RFC 6120.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 15, 2015. This Internet-Draft will expire on May 30, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3 3. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Support for TLS . . . . . . . . . . . . . . . . . . . . . 3 3.1. Support for TLS . . . . . . . . . . . . . . . . . . . . . 3
3.2. Compression . . . . . . . . . . . . . . . . . . . . . . . 3 3.2. Compression . . . . . . . . . . . . . . . . . . . . . . . 3
3.3. Session Resumption . . . . . . . . . . . . . . . . . . . 3 3.3. Session Resumption . . . . . . . . . . . . . . . . . . . 3
3.4. Authenticated Connections . . . . . . . . . . . . . . . . 3 3.4. Authenticated Connections . . . . . . . . . . . . . . . . 3
3.5. Unauthenticated Connections . . . . . . . . . . . . . . . 4 3.5. Unauthenticated Connections . . . . . . . . . . . . . . . 4
3.6. Server Name Indication . . . . . . . . . . . . . . . . . 4 3.6. Server Name Indication . . . . . . . . . . . . . . . . . 4
3.7. Human Factors . . . . . . . . . . . . . . . . . . . . . . 4 3.7. Human Factors . . . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5 6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6 6.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Implementation Notes . . . . . . . . . . . . . . . . 7 Appendix A. Implementation Notes . . . . . . . . . . . . . . . . 7
Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 7 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
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3.2. Compression 3.2. Compression
XMPP supports an application-layer compression technology [XEP-0138]. XMPP supports an application-layer compression technology [XEP-0138].
Although this XMPP extension might have slightly stronger security Although this XMPP extension might have slightly stronger security
properties than TLS-layer compression (since it is enabled after SASL properties than TLS-layer compression (since it is enabled after SASL
authentication, as described in [XEP-0170]), this document neither authentication, as described in [XEP-0170]), this document neither
encourages nor discourages use of XMPP-layer compression. encourages nor discourages use of XMPP-layer compression.
3.3. Session Resumption 3.3. Session Resumption
Use of session IDs [RFC5246] is RECOMMENDED instead of session
tickets [RFC5077], since XMPP does not in general use state
management technologies such as tickets or "cookies" [RFC6265].
In XMPP, TLS session resumption can be used in concert with the XMPP In XMPP, TLS session resumption can be used in concert with the XMPP
Stream Management extension; see [XEP-0198] for further details. Stream Management extension; see [XEP-0198] for further details.
3.4. Authenticated Connections 3.4. Authenticated Connections
Both the core XMPP specification [RFC6120] and the "CertID" Both the core XMPP specification [RFC6120] and the "CertID"
specification [RFC6125] provide recommendations and requirements for specification [RFC6125] provide recommendations and requirements for
certificate validation in the context of authenticated connections. certificate validation in the context of authenticated connections.
This document does not supersede those specifications. Wherever This document does not supersede those specifications. Wherever
possible, it is best to prefer authenticated connections (along with possible, it is best to prefer authenticated connections (along with
SASL [RFC4422]), as already stated in the core XMPP specification SASL [RFC4422]), as already stated in the core XMPP specification
[RFC6120]. In particular, clients MUST authenticate servers. [RFC6120]. In particular, clients MUST authenticate servers.
Because this document does not mandate that servers need to
authenticate peer servers, unauthenticated server-to-server
connections are allowed (consistent with current practice on the XMPP
network).
This document does not modify the recommendations in [RFC6120]
regarding the Subject Alternative Names (or other certificate
details) that need to be supported for authentication of XMPP
connections.
3.5. Unauthenticated Connections 3.5. Unauthenticated Connections
Given the pervasiveness of passive eavesdropping, even an Given the pervasiveness of passive eavesdropping, even an
unauthenticated connection might be better than an unencrypted unauthenticated connection might be better than an unencrypted
connection (this is similar to the "better than nothing security" connection (this is similar to the "better than nothing security"
approach for IPsec [RFC5386]). In particular, because of current approach for IPsec [RFC5386]). In particular, because of current
deployment challenges for authenticated connections between XMPP deployment challenges for authenticated connections between XMPP
servers (see [I-D.ietf-xmpp-dna] and [I-D.ietf-xmpp-posh] for servers (see [I-D.ietf-xmpp-dna] and [I-D.ietf-xmpp-posh] for
details), it might be reasonable for XMPP server implementations to details), it can be reasonable for XMPP server implementations to
accept unauthenticated connections when the Server Dialback protocol accept unauthenticated connections when the Server Dialback protocol
[XEP-0220] is used for weak identity verification; this will at least [XEP-0220] is used for weak identity verification; this will at least
enable encryption of server-to-server connections. Unauthenticated enable encryption of server-to-server connections. Unauthenticated
connections include connections negotiated using anonymous Diffie- connections include connections negotiated using anonymous Diffie-
Hellman algorithms or using self-signed certificates, among other Hellman algorithms or using self-signed certificates, among other
scenarios. scenarios.
3.6. Server Name Indication 3.6. Server Name Indication
Although there is no harm in supporting the TLS Server Name Although there is no harm in supporting the TLS Server Name
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Sheffer, Y., Holz, R., and P. Saint-Andre, Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of TLS and DTLS", draft- "Recommendations for Secure Use of TLS and DTLS", draft-
ietf-uta-tls-bcp-07 (work in progress), November 2014. ietf-uta-tls-bcp-07 (work in progress), November 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4949] Shirey, R., "Internet Security Glossary, Version 2", RFC [RFC4949] Shirey, R., "Internet Security Glossary, Version 2", RFC
4949, August 2007. 4949, August 2007.
[RFC5077] Salowey, J., Zhou, H., Eronen, P., and H. Tschofenig,
"Transport Layer Security (TLS) Session Resumption without
Server-Side State", RFC 5077, January 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC6120] Saint-Andre, P., "Extensible Messaging and Presence [RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Core", RFC 6120, March 2011. Protocol (XMPP): Core", RFC 6120, March 2011.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509 within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer (PKIX) Certificates in the Context of Transport Layer
skipping to change at page 6, line 48 skipping to change at page 6, line 48
[RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and [RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and
Security Layer (SASL)", RFC 4422, June 2006. Security Layer (SASL)", RFC 4422, June 2006.
[RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing [RFC5386] Williams, N. and M. Richardson, "Better-Than-Nothing
Security: An Unauthenticated Mode of IPsec", RFC 5386, Security: An Unauthenticated Mode of IPsec", RFC 5386,
November 2008. November 2008.
[RFC6066] Eastlake, D., "Transport Layer Security (TLS) Extensions: [RFC6066] Eastlake, D., "Transport Layer Security (TLS) Extensions:
Extension Definitions", RFC 6066, January 2011. Extension Definitions", RFC 6066, January 2011.
[RFC6265] Barth, A., "HTTP State Management Mechanism", RFC 6265,
April 2011.
[XEP-0138] [XEP-0138]
Hildebrand, J. and P. Saint-Andre, "Stream Compression", Hildebrand, J. and P. Saint-Andre, "Stream Compression",
XSF XEP 0138, May 2009. XSF XEP 0138, May 2009.
[XEP-0170] [XEP-0170]
Saint-Andre, P., "Recommended Order of Stream Feature Saint-Andre, P., "Recommended Order of Stream Feature
Negotiation", XSF XEP 0170, January 2007. Negotiation", XSF XEP 0170, January 2007.
[XEP-0198] [XEP-0198]
Karneges, J., Saint-Andre, P., Hildebrand, J., Forno, F., Karneges, J., Saint-Andre, P., Hildebrand, J., Forno, F.,
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