draft-ietf-mmusic-4572-update-01.txt   draft-ietf-mmusic-4572-update-02.txt 
Network Working Group C. Holmberg Network Working Group C. Holmberg
Internet-Draft Ericsson Internet-Draft Ericsson
Updates: 4572 (if approved) May 5, 2016 Updates: 4572 (if approved) May 18, 2016
Intended status: Standards Track Intended status: Standards Track
Expires: November 6, 2016 Expires: November 19, 2016
Updates to RFC 4572 Updates to RFC 4572
draft-ietf-mmusic-4572-update-01.txt draft-ietf-mmusic-4572-update-02.txt
Abstract Abstract
This document updates RFC 4572 by clarifying the usage of multiple This document updates RFC 4572 by clarifying the usage of multiple
SDP 'fingerprint' attributes with a single TLS connection. The SDP 'fingerprint' attributes with a single TLS connection. The
document also updates the preferred cipher suite to be used, and document also updates the preferred cipher suite to be used, and
removes the requirement to use the same hash function for calculating removes the requirement to use the same hash function for calculating
the certificate fingerprint that is used to calculate the certificate a certificate fingerprint that is used to calculate the certificate
signature. signature.
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
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 November 6, 2016. This Internet-Draft will expire on November 19, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 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
skipping to change at page 2, line 14 skipping to change at page 2, line 14
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Update to RFC 4572 . . . . . . . . . . . . . . . . . . . . . 3 3. Update to RFC 4572 . . . . . . . . . . . . . . . . . . . . . 3
3.1. Update to the sixth paragraph of section 5 . . . . . . . 3 3.1. Update to the sixth paragraph of section 5 . . . . . . . 3
3.2. New paragraphs to the end of section 5 . . . . . . . . . 4 3.2. New paragraphs to the end of section 5 . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 6
8. Normative References . . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
RFC 4572 [RFC4572] specifies how to establish Transport Layer RFC 4572 [RFC4572] specifies how to establish Transport Layer
Security (TLS) connections using the Session Description Protocol Security (TLS) connections using the Session Description Protocol
(SDP) [RFC4566]. (SDP) [RFC4566].
RFC 4572 defines the SDP 'fingerprint' attribute, which is used to RFC 4572 defines the SDP 'fingerprint' attribute, which is used to
carry a secure hash value associated with a certificate. However, carry a secure hash value (fingerprint) associated with a
RFC 4572 is currently unclear on whether multiple 'fingerprint' can certificate. However, RFC 4572 is currently unclear on whether
be associated with a single SDP media description ("m= line") multiple 'fingerprint' attributes can be associated with a single SDP
[RFC4566], and the associated semantics. Multiple 'fingerprint' media description ("m= line") [RFC4566], and the associated
attributes are needed when an endpoint wants to provide multiple semantics. Multiple fingerprints are needed if an endpoints wants to
fingerprint, using different hash functions, for a certificate. provide fingerprints associated with multiple certificates. For
Multiple 'fingerprint' attributes are also needed if an endpoint example, with RTP-based media, an endpoint might use different
wants to provide fingerprints associated with multiple certificates.
For example, with RTP-based media, an endpoint might use different
certificates for RTP and RTCP. certificates for RTP and RTCP.
RFC 4572 also specifies a preferred cipher suite. However, the RFC 4572 also specifies a preferred cipher suite. However, the
currently preferred cipher suite is considered outdated, and the currently preferred cipher suite is considered outdated, and the
preference needs to be updated. preference needs to be updated.
RFC 4572 mandates that the hash function used to calculate the RFC 4572 mandates that the hash function used to calculate the
fingerprint is the same hash function used to calculate the fingerprint is the same hash function used to calculate the
certificate signature. That requirement might prevent usage of certificate signature. That requirement might prevent usage of
newer, stronger and more collision-safe hash functions for newer, stronger and more collision-safe hash functions for
calculating certificate fingerprints. calculating certificate fingerprints. This change also requires that
multiple 'fingerprint' attributes can be associated with a single
"m=" line, so that implementations are able to provide fingerprints
calculated using updated hash functions alongside those that are
needed to interoperate with existing implementations.
This document updates RFC 4572 [RFC4572] by clarifying the usage of This document updates RFC 4572 [RFC4572] by clarifying the usage of
multiple SDP 'fingerprint' attributes with a single TLS connection. multiple SDP 'fingerprint' attributes. It is clarified that multiple
The document also updates the preferred cipher suite to be used, and 'fingerprint' attributes can be used to carry fingerprints,
removes the requirement to use the same hash function for calculating calculated using different hash functions, associated with a given
the certificate fingerprint and certificate signature. certificate, and to carry fingerprints associated with multiple
certificates. The fingerprint matching procedure, when multiple
fingerprints are provided, are also clarified. The document also
updates the preferred cipher suite to be used, and removes the
requirement to use the same hash function for calculating a
certificate fingerprint and certificate signature.
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
3. Update to RFC 4572 3. Update to RFC 4572
This section updates section 5 of RFC 4572. This section updates section 5 of RFC 4572.
skipping to change at page 4, line 6 skipping to change at page 5, line 4
Following RFC 3279 [7] as updated by RFC 4055 [9], therefore, the Following RFC 3279 [7] as updated by RFC 4055 [9], therefore, the
defined hash functions are 'SHA-1' [11] [19], 'SHA-224' [11], defined hash functions are 'SHA-1' [11] [19], 'SHA-224' [11],
'SHA-256' [11], 'SHA-384' [11], 'SHA-512' [11], 'MD5' [12], and 'SHA-256' [11], 'SHA-384' [11], 'SHA-512' [11], 'MD5' [12], and
'MD2' [13], with 'SHA-256' preferred. A new IANA registry of Hash 'MD2' [13], with 'SHA-256' preferred. A new IANA registry of Hash
Function Textual Names, specified in Section 8, allows for addition Function Textual Names, specified in Section 8, allows for addition
of future tokens, but they may only be added if they are included of future tokens, but they may only be added if they are included
in RFCs that update or obsolete RFC 3279 [7]. in RFCs that update or obsolete RFC 3279 [7].
3.2. New paragraphs to the end of section 5 3.2. New paragraphs to the end of section 5
NEW TEXT: NEW TEXT:
Multiple SDP fingerprint attributes can be associated with an m- Multiple SDP fingerprint attributes can be associated with an m-
line. This can occur if multiple fingerprints have been calculated line. This can occur if multiple fingerprints have been calculated
for a certificate, using different hash algorithms. It can also for a certificate, using different hash functions. It can also
occur if fingerprints associated with multiple certificates have occur if one or more fingerprints associated with multiple
been calculated, e.g. for cases where multiple certificates will be certificates have been calculated, e.g. for cases where multiple
used (e.g. separate certificates for RTP and RTCP), or where it is certificates will be used for media associated with an m- line
not known which certificate will be used when the fingerprints are (e.g. separate certificates for RTP and RTCP), or where it is not
known which certificate will be used when the fingerprints are
exchanged. In such cases, one or more fingerprints MUST be exchanged. In such cases, one or more fingerprints MUST be
calculated for each possible certificate. A different number of calculated for each possible certificate.
fingerprints can be calculated for each certificate, and different
hash algorithms can be used.
An endpoint MUST be able to match at least one of the received If fingerprints associated with multiple certificates are
fingerprints, calculated using a hash algorithm that the endpoint calculated, the same set of fingerprints (using the same hash
considers secure enough, with the certificate(s) that will functions) MUST be calculated for each certificate associated
eventually be used. If there is no match, the endpoint MUST NOT with the m- line.
establish the TLS connection.
For each used certificate, an endpoint MUST be able to match at
least one fingerprint, calculated using the hash function that the
endpoint supports and considers most secure, with the used
certificate. If there is no match, the endpoint MUST NOT establish
the TLS connection. In addition, the endpoint MAY also check other
fingerprints (calculated using other hash functions) that it has
received for a match. For each hash function checked, one of the
received fingerprints MUST match the used certificate.
NOTE: The SDP fingerprint attribute does not contain a reference to NOTE: The SDP fingerprint attribute does not contain a reference to
a specific certificate. Endpoints need to compare the fingerprint a specific certificate. Endpoints need to compare the fingerprint
witha certificate hash in order to look for a match. with a certificate hash in order to look for a match.
4. Security Considerations 4. Security Considerations
This document improves security. It updates the preferred hash This document improves security. It updates the preferred hash
function cipher suite from SHA-1 to SHA-256. By clarifying the usage function cipher suite from SHA-1 to SHA-256. By clarifying the usage
and handling of multiple fingerprints, the document also enables hash and handling of multiple fingerprints, the document also enables hash
agility, and incremental deployment of newer, and more secure, cipher agility, and incremental deployment of newer, and more secure, cipher
suites. suites.
5. IANA Considerations 5. IANA Considerations
This document makes no requests from IANA. This document makes no requests from IANA.
6. Acknowledgements 6. Acknowledgements
Martin Thompson, Paul Kyzivat, Jonathan Lennox and Roman Shpount Martin Thomson, Paul Kyzivat, Jonathan Lennox and Roman Shpount
provided valuable comments and input on this document. provided valuable comments and input on this document.
7. Change Log 7. Change Log
[RFC EDITOR NOTE: Please remove this section when publishing] [RFC EDITOR NOTE: Please remove this section when publishing]
Changes from draft-ietf-mmusic-4572-update-01
o Changes based on comments from Martin Thomson.
o - Editorial fixes
o Changes in handling of multiple fingerprints.
o - Sender must send same set of hash functions for each offered
certificate.
o - Receiver must check the hash function it considers most secure
for a match. It may check other hash functions.
Changes from draft-ietf-mmusic-4572-update-00 Changes from draft-ietf-mmusic-4572-update-00
o Changes in handling of multiple fingerprints. o Changes in handling of multiple fingerprints.
o - Number of fingerprints calculated for each certificate does not o - Number of fingerprints calculated for each certificate does not
have to match. have to match.
o - Clarified that receiver shall check check fingerprints using o - Clarified that receiver shall check check fingerprints using
hash algorithms it considers safe. hash algorithms it considers safe.
o - Additional text added to security considerations section. o - Additional text added to security considerations section.
Changes from draft-holmberg-mmusic-4572-update-01 Changes from draft-holmberg-mmusic-4572-update-01
o Adopted WG document (draft-ietf-mmusic-4572-update-00) submitted. o Adopted WG document (draft-ietf-mmusic-4572-update-00) submitted.
o IANA considerations section added. o IANA considerations section added.
8. Normative References 8. References
8.1. Normative References
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model
with Session Description Protocol (SDP)", RFC 3264, with Session Description Protocol (SDP)", RFC 3264,
DOI 10.17487/RFC3264, June 2002, DOI 10.17487/RFC3264, June 2002,
<http://www.rfc-editor.org/info/rfc3264>. <http://www.rfc-editor.org/info/rfc3264>.
skipping to change at page 6, line 5 skipping to change at page 7, line 25
[RFC4572] Lennox, J., "Connection-Oriented Media Transport over the [RFC4572] Lennox, J., "Connection-Oriented Media Transport over the
Transport Layer Security (TLS) Protocol in the Session Transport Layer Security (TLS) Protocol in the Session
Description Protocol (SDP)", RFC 4572, Description Protocol (SDP)", RFC 4572,
DOI 10.17487/RFC4572, July 2006, DOI 10.17487/RFC4572, July 2006,
<http://www.rfc-editor.org/info/rfc4572>. <http://www.rfc-editor.org/info/rfc4572>.
[RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
Description Protocol", RFC 4566, DOI 10.17487/RFC4566, Description Protocol", RFC 4566, DOI 10.17487/RFC4566,
July 2006, <http://www.rfc-editor.org/info/rfc4566>. July 2006, <http://www.rfc-editor.org/info/rfc4566>.
8.2. Informative References
[RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific
Media Attributes in the Session Description Protocol
(SDP)", RFC 5576, DOI 10.17487/RFC5576, June 2009,
<http://www.rfc-editor.org/info/rfc5576>.
[I-D.ietf-mmusic-sdp-mux-attributes]
Nandakumar, S., "A Framework for SDP Attributes when
Multiplexing", draft-ietf-mmusic-sdp-mux-attributes-12
(work in progress), January 2016.
[I-D.ietf-mmusic-sdp-bundle-negotiation]
Holmberg, C., Alvestrand, H., and C. Jennings,
"Negotiating Media Multiplexing Using the Session
Description Protocol (SDP)", draft-ietf-mmusic-sdp-bundle-
negotiation-29 (work in progress), April 2016.
Author's Address Author's Address
Christer Holmberg Christer Holmberg
Ericsson Ericsson
Hirsalantie 11 Hirsalantie 11
Jorvas 02420 Jorvas 02420
Finland Finland
Email: christer.holmberg@ericsson.com Email: christer.holmberg@ericsson.com
 End of changes. 18 change blocks. 
42 lines changed or deleted 91 lines changed or added

This html diff was produced by rfcdiff 1.45. The latest version is available from http://tools.ietf.org/tools/rfcdiff/