Internet Engineering Task Force A. Newton, Ed.
Internet-Draft ARIN
Intended status: Informational C. Martinez-Cagnazzo, Ed.
Expires: January 19, 2018 LACNIC
D. Shaw
AFRINIC
T. Bruijnzeels
RIPE NCC
B. Ellacott
APNIC
July 18, 2017
RPKI Multiple "All Resources" Trust Anchors Applicability Statement
draft-rir-rpki-allres-ta-app-statement-02
Abstract
This document provides an applicability statement for the use of
multiple, over-claiming 'all resources' (0/0) RPKI certificate
authorities (CA) certificates used as trust anchors (TAs) operated by
the Regional Internet Registry community to help mitigate the risk of
massive downstream invalidation in the case of transient registry
inconsistencies.
Status of This Memo
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This Internet-Draft will expire on January 19, 2018.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Internet-Draft RPKI 0/0 TA Applicability Statement July 2017
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Table of Contents
1. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Applicability to reduce overclaiming possibilities . . . . . 3
4. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Introduction
The RPKI is a hierarchical cryptologic system that uses X.509
certificates to match and validate holdership of Internet number
resources. This validation follows the allocation change from IANA
to an RIR, to an NIR or LIR, and ending with end users who make use
of the address block. Since these allocations can be
cryptographically validated, this can then be tied to assertions made
by the holder of those number resources. As an improvement of this
system, the RPKI was updated to add validation of origin routing
announcements via ROAs. These ROAs can then be independently and
cryptographically validated by third parties to assure themselves
that the origin of the announcement as seen in the actual routing
system is valid.
Since this system is envisioned to be used by network operators and
ISPs to determine their routing decisions, there is a goal to be 100%
correct 100% of the time. This goal could be achieved if the system
was contained in a static environment where there is little or no
movement of holdership changes from one organization to another of
number resources. Unfortunately, this state cannot be achieved
today, as movement of number resouces from from organization to
organization is becoming common largely due to IPv4 scarcity.
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Unfortunately, this state of 100% correctness at all times is
infeasible in a model where separate entities are operating
independently, yet rely critically on each others' perfect
synchronisation at all times.
Because the current validation mechanism is all-or-nothing, any
inconsistency at all at a high apex CA has the potential to
invalidate a large number of additional Internet Number Resources.
The higher the apex, and the larger the total set of INRs maintained
by the CA, the greater the impact of even a small inconsistency.
As resources do change at high apex CAs for a variety of reasons, the
likelihood of a small inconsistency is non-zero. And the likelihood
of a transitional inconsistency is moderate. Due to the distributed
nature of the RPKI repository mechanism, even if all CAs were able to
operate in perfect synchronicity at all times, there is a reasonable
likelihood that a given validating client may witness a temporarily
inconsistent state of the system as a whole. A risk of wide-spread
invalidity therefore exists as a very high impact and moderate
likelihood event.
This brittleness in the RPKI validation rules has been identified and
presented by the current RPKI TA operators to the IETF. A solution
has also been proposed
([I-D.ietf-sidr-rpki-validation-reconsidered]), a solution that would
allow for accidental over-claiming only to invalidate the resource
that is incorrectly listed and allow the remaining to continue to be
valid. As the implementation and deployment of solutions to this
problem will occur according to timelines outside the control of the
current TA operators, the workaround proposed in the present draft
provides an acceptable trade-off.
3. Applicability to reduce overclaiming possibilities
The consequences of an RIR over-claiming are grave given that every
ISP within their certificate would be invalidated. If routing was to
be reliant on RPKI at this point, all routes announced by those ISPs
below the affected RIR certificate would cease to work.
To mitigate risk and alleviate this threat, each RIR will move from a
Trust Anchor that reflects their current holdings only, to one that
reflects all holdings (e.g. 0/0). This will then ensure that over-
claiming can not occur at a RIR level when dealing with transfers
from one RIR to another. RPKI validators will not see the five Trust
anchors from the RIRs as over-claiming and validation can proceed
normally.
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For those who may want to audit the RIRs to ensure that RIRs are not
allocating the same IP addresses in separate regions, this can be
done by matching the inventory of each RIR ([NROSTATS]) that is
provided by the RIRs with the certificates issued by the RIRs within
the RPKI.
Note that there will be minor changes from time to time to account
for movements from IP address holdings that are in flight from one
RIR to another and that transient overlaps can, and probably will,
occur as inter-RIR transfers become more and more common.
4. Normative References
[I-D.ietf-sidr-rpki-validation-reconsidered]
Huston, G., Michaelson, G., Martinez, C., Bruijnzeels, T.,
Newton, A., and D. Shaw, "RPKI Validation Reconsidered",
draft-ietf-sidr-rpki-validation-reconsidered-06 (work in
progress), July 2016.
[NROSTATS]
"NRO Extended Stats File", July 2016,
<https://www.nro.net/wp-content/uploads/apnic-uploads/
delegated-extended>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
Authors' Addresses
Andrew Newton (editor)
ARIN
Chantilly VA
United States
Email: andy@arin.net
Carlos Martinez-Cagnazzo (editor)
LACNIC
Montevideo
Uruguay
Email: carlos@lacnic.net
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Daniel Shaw
AFRINIC
Cybercity Ebene
Republic of Mauritius
Email: daniel@afrinic.net
Tim Bruijnzeels
RIPE NCC
Amsterdam
Netherlands
Email: tim@ripe.net
Byron Ellacott
APNIC
Brisbane
Australia
Email: bje@apnic.net
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