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stateless-ipip-proxy.txt
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stateless-ipip-proxy.txt
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anima Working Group M. Richardson
Internet-Draft Sandelman Software Works
Intended status: Standards Track June 05, 2018
Expires: December 7, 2018
Stateless IPIP proxy for Bootstrapping Protocols
draft-richardson-anima-6tisch-stateless-ipip-proxy-00
Abstract
This document defines a mechanism for a Join Proxy used in a variety
of related enrollment protocols to forward arbitrary traffic in a
stateless fashion.
This mechanism uses IPIP encapsulation which can be compressed by 6lo
mechanism.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on December 7, 2018.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
Richardson Expires December 7, 2018 [Page 1]
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
4. Detailed Protocol Description . . . . . . . . . . . . . . . . 4
5. Design Considerations for Server Implementation . . . . . . . 4
6. Security Considerations . . . . . . . . . . . . . . . . . . . 4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
9. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 4
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
10.1. Normative References . . . . . . . . . . . . . . . . . . 4
10.2. Informative References . . . . . . . . . . . . . . . . . 5
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Enrollment of new nodes into constrained networks with constrained
nodes present unique challenges.
There are bandwidth and code space issues to contend. Solutions such
as [I-D.ietf-anima-bootstrapping-keyinfra] and
[I-D.ietf-6tisch-dtsecurity-zerotouch-join] require that a new node
(the "pledge") be helped by a Join Proxy.
The Join Proxy needs to forward traffic from the Pledge to the Join
Registrar/Coordinator (JRC), and then return responses from the JRC
to the Pledge. As detailed in
[I-D.richardson-anima-state-for-joinrouter] there are many methods
that can be used to forward the traffic.
In each of the two join scenarios, the traffic between the Pledge and
the Join Proxy is IPv6 Link-Local traffic. The Pledge has no default
gateway, nor any global routable address. The Pledge believes a
fiction that it has communicating with a JRC that is one link-local
hop away. The fiction is created so that the not-yet-trustworthy
Pledge is not allocated any network resources, nor is it is permitted
to communicate for any purpose other than enrollment.
In all proxy mechanisms forwarding traffic to the JRC is relatively
easy. The traffic to the JRC appears to come from the Join Proxy,
and non-Link-Local addresses are used (ULA ACP addresses in ANIMA/
BRSKI, and GUA addresses in 6tisch, which has no ACP).
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The problem is returning traffic from the JRC to the correct Pledge.
In general, there may be more than one Pledge active at any time, so
some state is necessary to find the correct Pledge for a given
packet.
{{I-D.ietf-6tisch-minimal-security} defines the "Stateless-Proxy CoAP
Option" to store the state in the packet that is sent to the JRC.
This eliminates the need to store any per-Pledge state in the Join
Proxy. This method only works for CoAP protocols where the security
is inside of CoAP (i.e. OSCORE), and fails for CoAPS (CoAP/DTLS), as
the new option can not be inserted.
[I-D.ietf-anima-bootstrapping-keyinfra] contains a mandatory to
implement (on the JRC!) use of a TCP circuit proxy. In it's
canonical 1990-era application firewall origins in the ALG proxy,
this requires a process running on the Join Proxy that connects two
TCP sockets together. The NAPT mechanisms as defined in [RFC3022]
can be used for the same effect. The origin address (the Pledge's
Link-Local address), is mapped to the Join Proxy's ACP address. A
temporary origin port number is allocated. The destination address
is statically changed from the Join Proxy's Link-Local address to the
JRC's advertised address and port. While this NAT66 method is
cheaper than the historical ALG, it still has per-Pledge cost. As
the network on which device join may be open to any attacker, it is
quite reasonable to expect an attacker to attempt to overwhelm the
Join Proxy's state table.
This document provides a third option, IPIP encapsulation in which
UDP or TCP traffic (containing DTLS or TLS, or even raw CoAP) is
forwarded using the IPIP header to encapsulate the original packet,
and therefore maintaining the original headers. This is essentially
creation on a specific purpose Virtual (overlay) Network between the
Join Proxy and the JRC.
2. Terminology
The following terms are defined in [RFC8366], and are used
identically as in that document: artifact, imprint, domain, Join
Registrar/Coordinator (JRC), Manufacturer Authorized Signing
Authority (MASA), pledge, Trust of First Use (TOFU), and Voucher.
3. Requirements Language
In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119
[RFC2119] and indicate requirement levels for compliant STuPiD
implementations.
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4. Detailed Protocol Description
TBD.
5. Design Considerations for Server Implementation
TBD
6. Security Considerations
TBD
7. IANA Considerations
TBD.
8. Acknowledgements
TBD.
9. Changelog
10. References
10.1. Normative References
[I-D.ietf-6tisch-dtsecurity-zerotouch-join]
Richardson, M. and B. Damm, "6tisch Zero-Touch Secure Join
protocol", draft-ietf-6tisch-dtsecurity-zerotouch-join-02
(work in progress), April 2018.
[I-D.ietf-ace-coap-est]
Stok, P., Kampanakis, P., Kumar, S., Richardson, M.,
Furuhed, M., and S. Raza, "EST over secure CoAP (EST-
coaps)", draft-ietf-ace-coap-est-00 (work in progress),
February 2018.
[I-D.ietf-anima-bootstrapping-keyinfra]
Pritikin, M., Richardson, M., Behringer, M., Bjarnason,
S., and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructures (BRSKI)", draft-ietf-anima-bootstrapping-
keyinfra-15 (work in progress), April 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, <https://www.rfc-
editor.org/info/rfc2119>.
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[RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70,
RFC 5652, DOI 10.17487/RFC5652, September 2009,
<https://www.rfc-editor.org/info/rfc5652>.
[RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J.,
Weiler, S., and T. Kivinen, "Using Raw Public Keys in
Transport Layer Security (TLS) and Datagram Transport
Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250,
June 2014, <https://www.rfc-editor.org/info/rfc7250>.
[RFC8138] Thubert, P., Ed., Bormann, C., Toutain, L., and R. Cragie,
"IPv6 over Low-Power Wireless Personal Area Network
(6LoWPAN) Routing Header", RFC 8138, DOI 10.17487/RFC8138,
April 2017, <https://www.rfc-editor.org/info/rfc8138>.
10.2. Informative References
[I-D.ietf-6tisch-minimal-security]
Vucinic, M., Simon, J., Pister, K., and M. Richardson,
"Minimal Security Framework for 6TiSCH", draft-ietf-
6tisch-minimal-security-05 (work in progress), March 2018.
[I-D.richardson-anima-state-for-joinrouter]
Richardson, M., "Considerations for stateful vs stateless
join router in ANIMA bootstrap", draft-richardson-anima-
state-for-joinrouter-02 (work in progress), January 2018.
[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Address Translator (Traditional NAT)", RFC 3022,
DOI 10.17487/RFC3022, January 2001, <https://www.rfc-
editor.org/info/rfc3022>.
[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
<https://www.rfc-editor.org/info/rfc6690>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013, <https://www.rfc-
editor.org/info/rfc7030>.
[RFC8366] Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
"A Voucher Artifact for Bootstrapping Protocols",
RFC 8366, DOI 10.17487/RFC8366, May 2018,
<https://www.rfc-editor.org/info/rfc8366>.
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Author's Address
Michael Richardson
Sandelman Software Works
Email: [email protected]
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