SIDR Operations Z. Yan
Internet-Draft CNNIC
Intended status: Best Current Practice R. Bush
Expires: 28 October 2023 IIJ Research Lab & Arrcus, Inc.
G.G. Geng
Jinan University
T. de Kock
RIPE NCC
J. Yao
CNNIC
April 2023
Avoidance of ROA Containing Multiple IP Prefixes
draft-ietf-sidrops-roa-considerations-08
Abstract
When using the Resource Public Key Infrastructure (RPKI), address
space holders need to issue Route Origin Authorization (ROA)
object(s) to authorize one or more Autonomous Systems (ASes) to
originate routes to IP address prefix(es). This memo discusses
operational problems which may arise from ROAs containing multiple IP
prefixes and recommends that each ROA contains a single IP prefix.
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
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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 3 October 2023.
Copyright Notice
Copyright (c) 2023 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
4. Recommendations . . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
In the RPKI, a ROA is a digitally signed object which identifies that
a single AS has been authorized by the address space holder to
originate routes to one or more IP prefixes within the related
address space [RFC6482].
Each ROA contains an "asID" field and an "ipAddrBlocks" field. The
"asID" field contains a single AS number which is authorized to
originate routes to the given IP address prefix(es). The
"ipAddrBlocks" field contains one or more IP address prefixes to
which the AS is authorized to originate the routes.
If the address space holder needs to authorize more than one AS to
advertise the same set of IP prefixes, multiple ROAs must be issued
(one for each AS number [RFC6480]). Prior to this document, there
was no guidance recommending the issuance of a separate ROA for each
IP prefix or a single ROA containing multiple IP prefixes.
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2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Problem Statement
An address space holder can issue a separate ROA for each of its
routing announcements. Alternatively, for a given asID, it can issue
a single ROA for multiple routing announcements, or even for all of
its routing announcements. Since a given ROA is either valid or
invalid, the routing announcements for which that ROA was issued will
"share fate" when it comes to RPKI validation. Currently, no
guidance is offered in existing RFCs to recommend what kinds of ROA
are issued: one per prefix, or one ROA for multiple routing
announcements. The problem of fate-sharing was not discussed or
addressed.
In the RPKI trust chain, the Certification Authority (CA) certificate
issued by a parent CA to a delegate of some resources may be revoked
by the parent at any time resulting in changes to resources specified
in the [RFC3779] certificate extension. Any ROA object that includes
resources which are a) no longer entirely contained in the new CA
certificate, or b) contained in a new CA certificate that has not yet
been discovered by Relying Party (RP) software, will be rejected as
invalid. Since ROA invalidity affects all routes specified in that
ROA, unchanged resources with associated routes via that asID cannot
be separated from those affected by the change in the CA certificate
validity. They will fall under this invalid ROA even though there
was no intention to change their validity. Had these resources been
in a separate ROA, there would have been no change to the issuing CA
certificate, and therefore no subsequent invalidity.
CAs have to carefully coordinate ROA updates with resource
certificate updates. This process may be automated if a single
entity manages both the parent CA and the CA issuing the ROAs
(Scenario D in [RFC8211] Section 3). However, in other deployment
scenarios, this coordination becomes more complex.
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As there is a single expiration time for the entire ROA, expiration
will affect all prefixes in the ROA. Thus, any changes to the ROA
for any of the prefixes must be synchronized with any changes to
other prefixes, especially time-limitations on authorization for a
prefix. Had these prefixes been in separately issued ROAs, the
validity interval would be unique to each ROA, and invalidity would
only be affected by re-issuance of the specific parent CA certificate
which issued them.
A prefix could be allowed to be originated from an AS only for a
specific period of time, for example if the IP prefix was leased out
temporarily. This would be more difficult to manage, and potentially
be more error-prone if a ROA with multiple IP prefixes was used.
Similarly more complex routing may demand changes in asID or routes
for a subset of prefixes. Re-issuance of the ROA may cause change to
validity for all routes in the affected ROA. If the time limited
resources are in separate ROAs, or for more complex routing if each
change in asID or routes for a given prefix is reflected in a change
to a discrete ROA, then no change to validity of unaffected routes
will be caused.
The use of ROA with a single IP prefix can minimize these side-
effects. It avoids fate-sharing irrespective of the causes, where
the parent CA issuing each ROA remains valid and where each ROA
itself remains valid.
4. Recommendations
Unless the CA has good reasons to the contrary, issued ROA SHOULD
contain a single IP prefix.
5. Security Considerations
Issuing separate ROAs for independent IP prefixes may increase the
file fetch burden on RP during validation.
6. IANA Considerations
This document does not request any IANA action.
7. Acknowledgements
The authors wish to thank the following people for their review and
contributions to this document: George Michaelson, Tim Bruijnzeels,
Job Snijders, Di Ma, Geoff Huston, Tom Harrison, Rob Austein, Stephen
Kent, Christopher Morrow, Russ Housley, Ching-Heng Ku, Keyur Patel,
Cuiling Zhang and Kejun Dong. Thanks are also due to Warren Kumari
for the Security Area Directorate review.
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This work was supported by the Beijing Nova Program of Science and
Technology under grant Z191100001119113.
This document was produced using the xml2rfc tool [RFC2629].
8. References
8.1. Normative References
[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>.
[RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP
Addresses and AS Identifiers", RFC 3779,
DOI 10.17487/RFC3779, June 2004,
<https://www.rfc-editor.org/info/rfc3779>.
[RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support
Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480,
February 2012, <https://www.rfc-editor.org/info/rfc6480>.
[RFC6482] Lepinski, M., Kent, S., and D. Kong, "A Profile for Route
Origin Authorizations (ROAs)", RFC 6482,
DOI 10.17487/RFC6482, February 2012,
<https://www.rfc-editor.org/info/rfc6482>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8211] Kent, S. and D. Ma, "Adverse Actions by a Certification
Authority (CA) or Repository Manager in the Resource
Public Key Infrastructure (RPKI)", RFC 8211,
DOI 10.17487/RFC8211, September 2017,
<https://www.rfc-editor.org/info/rfc8211>.
8.2. Informative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
DOI 10.17487/RFC2629, June 1999,
<https://www.rfc-editor.org/info/rfc2629>.
Authors' Addresses
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Zhiwei Yan
CNNIC
No.4 South 4th Street, Zhongguancun
Beijing, 100190
P.R. China
Email: yanzhiwei@cnnic.cn
Randy Bush
IIJ Research Lab & Arrcus, Inc.
5147 Crystal Springs
Bainbridge Island, Washington 98110
United States of America
Email: randy@psg.com
Guanggang Geng
Jinan University
No.601, West Huangpu Avenue
Guangzhou
510632
P.R. China
Email: gggeng@jnu.edu.cn
Ties de Kock
RIPE NCC
Stationsplein 11
Amsterdam
Netherlands
Email: tdekock@ripe.net
Jiankang Yao
CNNIC
No.4 South 4th Street, Zhongguancun
Beijing, 100190
P.R. China
Email: yaojk@cnnic.cn
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