Internet DRAFT - draft-ymbk-sidrops-rpki-rov-timing
draft-ymbk-sidrops-rpki-rov-timing
Network Working Group R. Bush
Internet-Draft Internet Initiative Japan & Arrcus, Inc.
Intended status: Informational J. Borkenhagen
Expires: October 26, 2020 AT&T
T. Bruijnzeels
NLnet Labs
J. Snijders
NTT
April 24, 2020
Timing Parameters in the RPKI based Route Origin Validation Supply Chain
draft-ymbk-sidrops-rpki-rov-timing-00
Abstract
This document explores, and makes recommendations for, timing of
Resource Public Key Infrastructure publication of ROV data, their
propagation, and their use in Relying Parties and routers.
Requirements Language
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.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on October 26, 2020.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Related Work . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Certification Authority Publishing . . . . . . . . . . . . . 4
4. Relying Party Fetching . . . . . . . . . . . . . . . . . . . 4
5. Router Updating . . . . . . . . . . . . . . . . . . . . . . . 5
6. Effect on Routing . . . . . . . . . . . . . . . . . . . . . . 5
7. Alternative Technologies . . . . . . . . . . . . . . . . . . 5
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
10.1. Normative References . . . . . . . . . . . . . . . . . . 6
10.2. Informative References . . . . . . . . . . . . . . . . . 7
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
This document explores, and makes recommendations for, timing of
Resource Public Key Infrastructure (RPKI) publication of ROV data,
their propagation, and their use in Relying Parties (RP), caches and
routers.
The RPKI supply chain from CAs to reach routers has a structure as
follows:
Cerification Authorities: The authoritative data of the RPKI are
published by a distributed set of Certification Authorities (CAs)
at the IANA, RIRs, NIRs, and ISPs (see [RFC6481]).
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Publication Points: The CAs publish their authoritative data in
publicly accessible repositories which have a Publication Point
(PP) for each CA.
Relying Parties: Relying Parties are a local (to the routers) set of
one or more collected and verified caches of RPKI data which are
collected from the PPs.
Currently RPs can pull from other RPs, thereby creating a somewhat
complex topology.
Routers: Validating routers fetch data from local RP caches using
the RPKI to Router Protocol, [I-D.ietf-sidrops-8210bis]. Routers
are clients of the caches. Validating routers MUST have a trust
relationship with, and a trusted transport channel to, any RP(s)
they use. [I-D.ietf-sidrops-8210bis] specifies mechanisms for the
router to assure itself of the authenticity of the cache(s) and to
authenticate itself to cache(s).
As Resource Public Key Infrastructure based Route Origin Validation
(ROV) becomes deployed in the Internet, the quality of the routing
control plane, and hence timely and accurate delivery of packets in
the data plane, increasingly depend on prompt and accurate
propagation of the RPKI data from the originating Certification
Authorities (CAs), to Relying Parties (RPs), to Border Gateway
Protocol (BGP) speaking routers.
Origin Validation based on stale ROAs allows accidental or
intentional mis-origination; announcement of a prefix by an AS which
does not have the authority to do so. While delays in ROA
propagation to ROV in routers can cause loss of good traffic.
Therefore minimizing propagation time of data from CAs to routers is
critical.
Before the data can start on the CA to router chain, the resource
holder (operator) MUST create or delete the relevant ROA(s) through
the CA's operational interface(s). The operator is responsible for
anticipating their future needs for ROAs, be aware of the propagation
time from creating ROAs to effect on routing, and SHOULD create,
delete, or modify ROAs sufficiently in advance of any needs in the
routing system.
There are questions of how frequently a CA publishes, how often an RP
pulls, and how often routers pull from their RP(s). Overall, the
router(s) SHOULD react within an hour of ROA publication.
For CAs publishing to PPs, a few seconds to a minute seems easily
achieved with reasonable software. See Section 3.
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Relying Party validating caches periodically retrieve data from CA
publication points. RPs using rsync to poll publication points every
ten minutes would be a burden today, given the load it would put on
publication services, cf. one notorious repository which is
structured against specification. RPs using RRDP impose no such
load. As the infrastructure moves from rsync to RRDP
[I-D.sidrops-bruijnzeels-deprecate-rsync], RRDP is designed for very
frequent polling as long as Relying Parties use the "If-Modified-
Since" header and there is a caching infrastructure. For rsync, an
hour would be the longest acceptable window. See Section 4.
For the BGP speaking router(s) pulling from the RP(s), five minutes
to an hour is a wide window. But, the RPKI-Rtr protocol does have
the Serial Notify PDU, the equivalent of DNS Notify, where the cache
tells the router that it has new data. See Section 5.
We discuss each of these in detail below.
2. Related Work
It is assumed that the reader understands BGP, [RFC4271], the RPKI
[RFC6480], RPKI Manifests [RFC6486], Route Origin Authorizations
(ROAs), [RFC6482], the RPKI Repository Delta Protocol (RRDP)
[RFC8182], The Resource Public Key Infrastructure (RPKI) to Router
Protocol [I-D.ietf-sidrops-8210bis], RPKI-based Prefix Validation,
[RFC6811], and Origin Validation Clarifications, [RFC8481].
3. Certification Authority Publishing
A principal constraint on publication timing is ensuring the CRL and
Manifest ([RFC6486]) are atomically correct with respect to the other
repository data. With rsync, the directory must be atomically
correct before it becomes current. RRDP ([RFC8182]) is similar, the
directory must be atomically correct before it is published.
4. Relying Party Fetching
rsync puts a load on RPKI publication point servers. Therefore
relying party caches have been discouraged from fetching more
frequently than on the order of an hour. Times as long as a day were
even suggested. We conclude that RPs using rsync SHOULD pull from CA
publication points once an hour.
With RRDP ([RFC8182]), such constraints are no longer relevant.
[RFC8182] makes clear that polling as frequently as once a second is
acceptable iff Relying Parties use the "If-Modified-Since" header and
there is caching. In such circumstances, the RRDP polling interval
MUST be no more than ten minutes. We strongly recommend the
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migration from rsync to RRDP in
[I-D.sidrops-bruijnzeels-deprecate-rsync].
Each validation run of each RP MUST generate the same set of
Validated ROA Payloads (VRPs) when presented with identical input,
using unexpired records from the most recent successful retrieval to
deal only with complete failure to retrieve from a PP.
A number of timers are embedded in the X.509 RPKI data which should
also be considered. E.g., CRL publication commitments, expiration of
EE certificates pointing to Manifests, and the Manifests themselves.
Some CA operators commonly indicate new CRL information should be
available in the next 24 hours. These 24-hour sliding timers,
combined with fetching RPKI data once a day, cause needless
brittleness in the face of transient network issues between the CA
and RP.
5. Router Updating
The rate of change of ROA data is estimated to remain small, on the
order of a few ROAs a minute, but with bursts. Therefore, the
routers may update from the (presumed local) relying party cache(s)
quite frequently. Note that [I-D.ietf-sidrops-8210bis] recommends a
polling interval of one hour. This timing is conservative because
caches can send a Serial Notify PDU to tell routers when there are
new data to be fetched.
A router SHOULD respond with a Serial Query when it receives a Serial
Notify from a cache. If a router can not respond appropriately to a
Serial Notify, then it MUST send a periodic Serial Query no less
frequently than once an hour.
6. Effect on Routing
Once a router has received an End of Data PDU from a cache, the
effect on Route Origin Validation MUST be a matter of seconds to a
minute. The router MAY allow incoming VRPs to affect Origin
Validation as they arrive instead of waiting for the End of Data PDU.
See [I-D.ietf-sidrops-8210bis] for some cautions regarding the
arrival sequence of VRPs.
7. Alternative Technologies
Should the supply chain include components or technologies other than
those in IETF documents, the end effect SHOULD be the same; the
router(s) SHOULD react to invalid AS origins within the same overall
time constraint, an hour at most from ROA creation at the CA
publication point to effect in the router.
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8. Security Considerations
Despite common misconceptions and marketing, Route Origin Validation
is not a security protocol. It is intended to catch operational
errors, and is easily gamed and attacked.
If an attacker can add, delete, or modify RPKI data, either in
repositories or in flight, they can affect routing and thereby steer
or damage traffic. The RPKI system design does much to deter these
attacks. But the 'last mile' from the cache to the router uses
transport, as opposed to object, security and is vulnerable. This is
discussed in [I-D.ietf-sidrops-8210bis].
Similarly, if an attacker can delay prompt propagation of RPKI data
on the supply chain described in this document, they can affect
routing, and therefore traffic flow, to their advantage.
9. IANA Considerations
None
10. References
10.1. Normative References
[I-D.ietf-sidrops-8210bis]
Bush, R. and R. Austein, "The Resource Public Key
Infrastructure (RPKI) to Router Protocol, Version 2",
draft-ietf-sidrops-8210bis-00 (work in progress), March
2020.
[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>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC6481] Huston, G., Loomans, R., and G. Michaelson, "A Profile for
Resource Certificate Repository Structure", RFC 6481,
DOI 10.17487/RFC6481, February 2012,
<https://www.rfc-editor.org/info/rfc6481>.
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[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>.
[RFC6486] Austein, R., Huston, G., Kent, S., and M. Lepinski,
"Manifests for the Resource Public Key Infrastructure
(RPKI)", RFC 6486, DOI 10.17487/RFC6486, February 2012,
<https://www.rfc-editor.org/info/rfc6486>.
[RFC6811] Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
Austein, "BGP Prefix Origin Validation", RFC 6811,
DOI 10.17487/RFC6811, January 2013,
<https://www.rfc-editor.org/info/rfc6811>.
[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>.
[RFC8182] Bruijnzeels, T., Muravskiy, O., Weber, B., and R. Austein,
"The RPKI Repository Delta Protocol (RRDP)", RFC 8182,
DOI 10.17487/RFC8182, July 2017,
<https://www.rfc-editor.org/info/rfc8182>.
[RFC8481] Bush, R., "Clarifications to BGP Origin Validation Based
on Resource Public Key Infrastructure (RPKI)", RFC 8481,
DOI 10.17487/RFC8481, September 2018,
<https://www.rfc-editor.org/info/rfc8481>.
10.2. Informative References
[I-D.sidrops-bruijnzeels-deprecate-rsync]
Bruijnzeels, T., "Resource Public Key Infrastructure
(RPKI) Repository Requirements", draft-sidrops-
bruijnzeels-deprecate-rsync-00 (work in progress),
November 2019.
[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>.
Appendix A. Acknowledgements
The authors wish to thank Jay Borkenhagen and Massimiliano Stucchi.
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Authors' Addresses
Randy Bush
Internet Initiative Japan & Arrcus, Inc.
5147 Crystal Springs
Bainbridge Island, Washington 98110
United States of America
Email: randy@psg.com
Jay Borkenhagen
AT&T
200 Laurel Avenue South
Middletown, NJ 07748
United States of America
Email: jayb@att.com
Tim Bruijnzeels
NLnet Labs
Email: tim@nlnetlabs.nl
URI: https://www.nlnetlabs.nl/
Job Snijders
NTT Ltd.
Theodorus Majofskistraat 100
Amsterdam 1065 SZ
The Netherlands
Email: job@ntt.net
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