A Default Validation Policy for the use of RPKI Manifests in the global Internet Routing System.
draft-spaghetti-sidrops-rpki-manifest-validation-00
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draft-spaghetti-sidrops-rpki-manifest-validation-00
Network Working Group J. Snijders
Internet-Draft NTT
Intended status: Informational May 3, 2020
Expires: November 4, 2020
A Default Validation Policy for the use of RPKI Manifests in the global
Internet Routing System.
draft-spaghetti-sidrops-rpki-manifest-validation-00
Abstract
Manifests are a critical cornerstone to the global Resource Public
Key Infrastructure (RPKI).
RFC 6486 describes a validation decision tree which introduced the
notion of 'local policy', creating space for ambiguity. This
ambiguity has led to various RPKI implementations producing different
output when presented with the same input, but also leads to severe
operational security implications.
This document updates RFC 6486 and introduces the notion of a default
policy for Manifest validation to encourage harmony between
implementations.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://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."
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This Internet-Draft will expire on November 4, 2020.
Copyright Notice
Copyright (c) 2020 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
(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 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
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Suggested Reading . . . . . . . . . . . . . . . . . . . . . . 3
3. The Problem . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Update to RFC 6486 . . . . . . . . . . . . . . . . . . . . . 3
4.1. Tests for Determining Manifest State . . . . . . . . . . 4
5. What to do when the CA's Publication Point is Distrusted . . 5
6. TODO . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
9.1. Normative References . . . . . . . . . . . . . . . . . . 5
9.2. Informative References . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
Manifests [RFC8416] are a critical cornerstone to the global Resource
Public Key Infrastructure RPKI [RFC6480].
RFC 6486 describes a validation decision tree which introduced the
notion of 'local policy', creating space for ambiguity. This
ambiguity has led to various RPKI implementations producing different
output when presented with the same input, but also operational
security implications.
This document updates RFC 6486 and introduces the notion of a global
policy for Manifest validation to encourage harmony between
implementations.
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2. Suggested Reading
It is assumed that the reader understands BGP, [RFC4271], the RPKI
[RFC6480], Route Origin Authorizations (ROAs) [RFC6482], RPKI-based
Prefix Validation, [RFC6811], and Origin Validation Clarifications
[RFC8481].
3. The Problem
It seems there is a mental trap in the RPKI system: contrary to
intuition, implementers should focus on validation policies which
minimize the number of Validated ROA Payloads (VRPs) at a RPKI cache.
If RPKI cache implementers mistreat untrusted network data and
'salvage whatever is possible', a number of critical issues are
introduced which compromise our ability to deploy RPKI ROV
incrementally. Only a single path through the RFC 6486 decision tree
is suitable for use in the global Internet system, as such that path
is the Default Policy.
If a dangerous condition is detected, not only MUST the manifest at
the publication point be distrusted, but all VRPs encompassed by the
IPAddrBlocks for which authority was delegated towards the
Certificate Authority (CA) at the distrusted pulication point be
removed from the RP's output. If the result is no VRPs at all (for
example because the RPKI subsystem is detected to be compromised at
the root), that is a preferred state for the Internet routing system.
The alternative is that a compromised RPKI system will permanently
disrupt the global Internet routing system.
4. Update to RFC 6486
This section replaces section 6 of [RFC6486] in its entirety.
The goal of an Relying Party (RP) is to determine which signed
objects to use for validating assertions about INRs and their use
(e.g., which VRPs to use in the construction of route filters). The
global Internet routing system is expected to benefit from uniform
application of a similar validation policy, as such in the following
sections we describe a sequence of tests that the RP MUST perform to
determine the manifest state of the given publication point according
to the default policy. We then discuss the risks associated with
using signed objects in the publication point, given the manifest
state; we also provide suitable warning text that SHOULD be placed in
a user-accessible log file. Note that if a certificate is deemed
unfit for use due to default policy, then any signed object that is
validated using this certificate also SHOULD be deemed unfit for use
(regardless of the status of the manifest at its own publication
point).
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4.1. Tests for Determining Manifest State
For a given publication point, the RP MUST perform the following
tests to determine the manifest state of the publication point:
1. For each CA using this publication point, select the CA's current
manifest (the "current" manifest is the manifest issued by this
CA having the highest manifestNumber among all valid manifests,
and where manifest validity is defined in Section 4.4 [RFC6486].
If the publication point does not contain a valid manifest, see
Section 5. Lacking a valid manifest, the following tests cannot
be performed.
2. To verify completeness, an RP MUST check that every file at each
publication point appears in one and only one current manifest,
and that every file listed in a current manifest is published at
the same publication point as the manifest.
3. If files exist at the publication point that do not appear on any
manifest, those can be ignored.
4. If files are listed in a manifest that do not appear at the
publication point, see Section 5.
5. Check that the current time (translated to UTC) is between
thisUpdate and nextUpdate. If the current time does not lie
within this interval, then see Section 5, but still continue with
the following tests.
6. Verify that the listed hash value of every file listed in each
manifest matches the value obtained by hashing the file at the
publication point. If the computed hash value of a file listed
on the manifest does not match the hash value contained in the
manifest, then see Section 5.
7. An RP MUST check that the contents of each current manifest
conforms to the manifest's scope constraints, as specified in
Section 2.
8. If a current manifest contains entries for objects that are not
within the scope of the manifest, then the out-of-scope entries
SHOULD be disregarded in the context of this manifest. If there
is no other current manifest that describes these objects within
that other manifest's scope, then see Section 5.
For each signed object, if all of the following conditions hold:
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the manifest for its publication and the associated publication
point pass all of the above checks;
the signed object is valid; and
the manifests for every certificate on the certification path used
to validate the signed object and the associated publication
points pass all of the above checks;
then the RP can conclude that no attack against the repository system
has compromised the given signed object, and the signed object MUST
be treated as valid (relative to manifest checking).
5. What to do when the CA's Publication Point is Distrusted
Once the RP has concluded the data at the publication point is
distrusted, the RP MUST remove all VRPs encompassed by the
IPAddrBlocks for which "right-of-use" authority was delegated to the
CA at the distrusted publication from its output, regardless of the
Trust Anchors.
6. TODO
o Mention RIR transfer cases
o The case for a most conservative approach: a 'fail-closed' policy
on the RPKI plane results in an collective ability to deploy ROV
on the shared EBGP plane: as the default remains 'fail open' (aka
'pre RPKI world'), operators in turn can deploy 'invalid ==
reject' policies on their EBGP sessions incrementally. A
brilliant strategy, however it strongly depends erring to the side
of caution (distrust?) in the validation process.
7. Security Considerations
... where to start
8. IANA Considerations
None
9. References
9.1. Normative References
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[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>.
[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>.
[RFC8416] Ma, D., Mandelberg, D., and T. Bruijnzeels, "Simplified
Local Internet Number Resource Management with the RPKI
(SLURM)", RFC 8416, DOI 10.17487/RFC8416, August 2018,
<https://www.rfc-editor.org/info/rfc8416>.
[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>.
9.2. Informative References
[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>.
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Appendix A. Acknowledgements
The authors wish to thank Rob Austein, Geoff Huston, Stephen Kent,
Matt Lepinski, Martin Hoffman, Randy Bush, and Theo de Raadt for
their insights and contributions which helped create this document.
Author's Address
Job Snijders
NTT Ltd.
Theodorus Majofskistraat 100
Amsterdam 1065 SZ
The Netherlands
Email: job@ntt.net
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