draft-ietf-tls-dtls-rrc-01.txt   draft-ietf-tls-dtls-rrc-02.txt 
TLS H. Tschofenig, Ed. TLS H. Tschofenig, Ed.
Internet-Draft T. Fossati Internet-Draft T. Fossati
Updates: 6347 (if approved) Arm Limited Updates: 6347 (if approved) Arm Limited
Intended status: Standards Track 25 October 2021 Intended status: Standards Track 26 November 2021
Expires: 28 April 2022 Expires: 30 May 2022
Return Routability Check for DTLS 1.2 and DTLS 1.3 Return Routability Check for DTLS 1.2 and DTLS 1.3
draft-ietf-tls-dtls-rrc-01 draft-ietf-tls-dtls-rrc-02
Abstract Abstract
This document specifies a return routability check for use in context This document specifies a return routability check for use in context
of the Connection ID (CID) construct for the Datagram Transport Layer of the Connection ID (CID) construct for the Datagram Transport Layer
Security (DTLS) protocol versions 1.2 and 1.3. Security (DTLS) protocol versions 1.2 and 1.3.
Discussion Venues Discussion Venues
This note is to be removed before publishing as an RFC. This note is to be removed before publishing as an RFC.
skipping to change at page 1, line 44 skipping to change at page 1, line 44
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 https://datatracker.ietf.org/drafts/current/. Drafts is at https://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 28 April 2022. This Internet-Draft will expire on 30 May 2022.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 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 (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components and restrictions with respect to this document. Code Components
extracted from this document must include Simplified BSD License text extracted from this document must include Revised BSD License text as
as described in Section 4.e of the Trust Legal Provisions and are described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License. provided without warranty as described in the Revised BSD License.
This document may contain material from IETF Documents or IETF This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this 10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process. modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format not be created outside the IETF Standards Process, except to format
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BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
This document assumes familiarity with the CID format and protocol This document assumes familiarity with the CID format and protocol
defined for DTLS 1.2 [I-D.ietf-tls-dtls-connection-id] and for DTLS defined for DTLS 1.2 [I-D.ietf-tls-dtls-connection-id] and for DTLS
1.3 [I-D.ietf-tls-dtls13]. The presentation language used in this 1.3 [I-D.ietf-tls-dtls13]. The presentation language used in this
document is described in Section 4 of [RFC8446]. document is described in Section 4 of [RFC8446].
3. RRC Extension 3. RRC Extension
This specification uses the tls_flags extension defined in The use of RRC is negotiated via the rrc DTLS-only extension. On
[I-D.ietf-tls-tlsflags] to allow a client and a server to negotiate connecting, the client includes the rrc extension in its ClientHello
support for this extension. if it wishes to use RRC. If the server is capable of meeting this
requirement, it responds with a rrc extension in its ServerHello.
The extension_type value for this extension is TBD1 and the
extension_data field of this extension is empty. The client and
server MUST NOT use RRC unless both sides have successfully exchanged
rrc extensions.
The RRC flag is assigned the value (TBD1) and is used in the Note that the RRC extension applies to both DTLS 1.2 and DTLS 1.3.
ClientHello (CH) and the ServerHello (SH).
4. The Return Routability Check Message 4. The Return Routability Check Message
When a record with CID is received that has the source address of the When a record with CID is received that has the source address of the
enclosing UDP datagram different from the one previously associated enclosing UDP datagram different from the one previously associated
with that CID, the receiver MUST NOT update its view of the peer's IP with that CID, the receiver MUST NOT update its view of the peer's IP
address and port number with the source specified in the UDP datagram address and port number with the source specified in the UDP datagram
before cryptographically validating the enclosed record(s) but before cryptographically validating the enclosed record(s) but
instead perform a return routability check. instead perform a return routability check.
enum { enum {
invalid(0), invalid(0),
change_cipher_spec(20), change_cipher_spec(20),
alert(21), alert(21),
handshake(22), handshake(22),
application_data(23), application_data(23),
heartbeat(24), /* RFC 6520 */ heartbeat(24), /* RFC 6520 */
return_routability_check(TBD), /* NEW */ return_routability_check(TBD2), /* NEW */
(255) (255)
} ContentType; } ContentType;
uint64 Cookie; uint64 Cookie;
enum { enum {
path_challenge(0), path_challenge(0),
path_response(1), path_response(1),
reserved(2..255) reserved(2..255)
} rrc_msg_type; } rrc_msg_type;
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5. Example 5. Example
The example TLS 1.3 handshake shown in Figure 1 shows a client and a The example TLS 1.3 handshake shown in Figure 1 shows a client and a
server negotiating the support for CID and for the RRC extension. server negotiating the support for CID and for the RRC extension.
Client Server Client Server
Key ^ ClientHello Key ^ ClientHello
Exch | + key_share Exch | + key_share
| + signature_algorithms | + signature_algorithms
| + tls_flags (RRC) | + rrc
v + connection_id=empty v + connection_id=empty
--------> -------->
ServerHello ^ Key ServerHello ^ Key
+ key_share | Exch + key_share | Exch
+ connection_id=100 | + connection_id=100 |
+ tls_flags (RRC) v + rrc v
{EncryptedExtensions} ^ Server {EncryptedExtensions} ^ Server
{CertificateRequest} v Params {CertificateRequest} v Params
{Certificate} ^ {Certificate} ^
{CertificateVerify} | Auth {CertificateVerify} | Auth
<-------- {Finished} v <-------- {Finished} v
^ {Certificate} ^ {Certificate}
Auth | {CertificateVerify} Auth | {CertificateVerify}
v {Finished} --------> v {Finished} -------->
[Application Data] <-------> [Application Data] [Application Data] <-------> [Application Data]
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6. Security and Privacy Considerations 6. Security and Privacy Considerations
Note that the return routability checks do not protect against Note that the return routability checks do not protect against
flooding of third-parties if the attacker is on-path, as the attacker flooding of third-parties if the attacker is on-path, as the attacker
can redirect the return routability checks to the real peer (even if can redirect the return routability checks to the real peer (even if
those datagrams are cryptographically authenticated). On-path those datagrams are cryptographically authenticated). On-path
adversaries can, in general, pose a harm to connectivity. adversaries can, in general, pose a harm to connectivity.
7. IANA Considerations 7. IANA Considerations
IANA is requested to allocate an entry to the TLS "ContentType" IANA is requested to allocate an entry to the TLS ContentType
registry, for the return_routability_check(TBD) defined in this registry, for the return_routability_check(TBD2) defined in this
document. document. The return_routability_check content type is only
applicable to DTLS 1.2 and 1.3.
IANA is requested to allocate an entry to the TLS Flags registry in
the tls_flags type:
* Value: [[IANA please assign a value from the 32-63 value range.]]
* Flag Name: RRC
* Message: CH,SH IANA is requested to allocate the extension code point (TBD1) for the
rrc extension to the TLS ExtensionType Values registry as described
in Table 1.
* Recommended: Y +=======+===========+=====+===========+=============+===========+
| Value | Extension | TLS | DTLS-Only | Recommended | Reference |
| | Name | 1.3 | | | |
+=======+===========+=====+===========+=============+===========+
| TBD1 | rrc | CH, | Y | N | RFC-THIS |
| | | SH | | | |
+-------+-----------+-----+-----------+-------------+-----------+
* Reference: [[This document]] Table 1: rrc entry in the TLS ExtensionType Values registry
8. Open Issues 8. Open Issues
Issues against this document are tracked at https://github.com/tlswg/ Issues against this document are tracked at https://github.com/tlswg/
dtls-rrc/issues dtls-rrc/issues
9. Acknowledgments 9. Acknowledgments
We would like to thank Achim Kraus, Hanno Becker, Hanno Boeck, Manuel We would like to thank Achim Kraus, Hanno Becker, Hanno Boeck, Manuel
Pegourie-Gonnard, Mohit Sahni and Rich Salz for their input to this Pegourie-Gonnard, Mohit Sahni and Rich Salz for their input to this
skipping to change at page 9, line 13 skipping to change at page 9, line 13
ietf-tls-dtls-connection-id-13>. ietf-tls-dtls-connection-id-13>.
[I-D.ietf-tls-dtls13] [I-D.ietf-tls-dtls13]
Rescorla, E., Tschofenig, H., and N. Modadugu, "The Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version Datagram Transport Layer Security (DTLS) Protocol Version
1.3", Work in Progress, Internet-Draft, draft-ietf-tls- 1.3", Work in Progress, Internet-Draft, draft-ietf-tls-
dtls13-43, 30 April 2021, dtls13-43, 30 April 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-tls- <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
dtls13-43>. dtls13-43>.
[I-D.ietf-tls-tlsflags]
Nir, Y., "A Flags Extension for TLS 1.3", Work in
Progress, Internet-Draft, draft-ietf-tls-tlsflags-06, 13
July 2021, <https://datatracker.ietf.org/doc/html/draft-
ietf-tls-tlsflags-06>.
[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,
<https://www.rfc-editor.org/rfc/rfc2119>. <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>. May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>. <https://www.rfc-editor.org/rfc/rfc8446>.
Appendix A. History Appendix A. History
RFC EDITOR: PLEASE REMOVE THE THIS SECTION // RFC EDITOR: PLEASE REMOVE THIS SECTION
draft-ietf-tls-dtls-rrc-02
* Undo the TLS flags extension for negotiating RRC, use a new
extension type
draft-ietf-tls-dtls-rrc-01 draft-ietf-tls-dtls-rrc-01
* Use the TLS flags extension for negotiating RRC * Use the TLS flags extension for negotiating RRC
* Enhanced IANA consideration section * Enhanced IANA consideration section
* Expanded example section * Expanded example section
* Revamp message layout: * Revamp message layout:
 End of changes. 15 change blocks. 
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