RPKI Validation Re-reconsidered
draft-spaghetti-sidrops-rpki-validation-update-01
The information below is for an old version of the document.
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| Authors | Job Snijders , Ben Maddison | ||
| Last updated | 2021-09-02 | ||
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draft-spaghetti-sidrops-rpki-validation-update-01
Network Working Group J. Snijders
Internet-Draft Fastly
Obsoletes: 8360 (if approved) B. Maddison
Updates: 6482, 6487 (if approved) Workonline
Intended status: Standards Track 2 September 2021
Expires: 6 March 2022
RPKI Validation Re-reconsidered
draft-spaghetti-sidrops-rpki-validation-update-01
Abstract
This document describes an improved validation procedure for Resource
Public Key Infrastructure (RPKI) signed objects. This document
updates RFC 6482. This document updates RFC 6487. This document
obsoletes RFC 8360.
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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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."
This Internet-Draft will expire on 6 March 2022.
Copyright Notice
Copyright (c) 2021 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
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as described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Deprecation of RFC 8360 . . . . . . . . . . . . . . . . . . . 2
3. Updates to RFC 6482 . . . . . . . . . . . . . . . . . . . . . 3
4. Updates to RFC 6487 . . . . . . . . . . . . . . . . . . . . . 4
4.1. Updates to Section 7.2 . . . . . . . . . . . . . . . . . 4
4.2. Updates to Section 9 . . . . . . . . . . . . . . . . . . 6
5. Implementation status - RFC EDITOR: REMOVE BEFORE
PUBLICATION . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
[RFC8360] describes an improved validation algorithm for signed
objects published in the RPKI. The improved validation algorithm
would help in situations such as described in this [Report].
However, operational experience has shown the described procedure for
deploying updates to the validation algorithm, as described in
[RFC6487] Section 9, is impractical. This document deprecates the
original [RFC6487] section 7 algorithm in favour of the [RFC8360]
algorithm, and obsoletes [RFC8360] because a migration via those
codepoints is infeasible. This document also deprecates the
procedure set out in [RFC6487] section 9 for future changes to the
validation algorithm.
1.1. 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.
2. Deprecation of RFC 8360
[RFC8360] defines several alternative OIDs for use in Resource
Certificates [RFC6487]:
* id-cp-ipAddr-asNumber-v2 - Section 4.2.1 [RFC8360]
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* id-pe-ipAddrBlocks-v2 - Sections 4.2.2.1 and 4.2.2.2 [RFC8360]
* id-pe-autonomousSysIds-v2 - Sections 4.2.2.3 and 4.2.2.4 [RFC8360]
The stated purpose of the above OIDs is rendered obsolete by the
updated specifications contained in this document.
Therefore:
* Issuing CAs MUST NOT include the above OIDs in newly issued
Resource Certificates; and
* Relying parties encountering the above OIDs in Resource
Certificates MUST proceed according to the updated procedures
described below.
3. Updates to RFC 6482
This section updates Section 4 [RFC6482]. The following text:
The IP address delegation extension [RFC3779] is present in the
end-entity (EE) certificate (contained within the ROA), and each
IP address prefix(es) in the ROA is contained within the set of IP
addresses specified by the EE certificate's IP address delegation
extension.
Is replaced with:
Either the IP Address Delegation extension described in [RFC3779]
or the alternative IP Address Delegation extension described in
[RFC8360] (but not both) is present in the end entity (EE)
certificate (contained within the ROA), and each IP address
prefix(es) in the ROA is contained within the VRS-IP set that is
specified as an outcome of EE certificate validation described in
Section 7.2 (as updated by this document) [RFC6487].
Note that this ensures that ROAs can be valid only if all IP address
prefixes in the ROA are encompassed by the VRS-IP of all certificates
along the path to the trust anchor used to verify it.
Operators MAY issue separate ROAs for each IP address prefix, so that
the loss of one or more IP address prefixes from the VRS-IP of any
certificate along the path to the trust anchor would not invalidate
authorizations for other IP address prefixes.
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4. Updates to RFC 6487
This section updates [RFC6487] to specify an improved behavior of a
Relying Party implementation.
4.1. Updates to Section 7.2
The following section replaces Section 7.2 [RFC6487] (Resource
Certification Path Validation) in its entirety.
Validation of signed resource data using a target resource
certificate consists of verifying that the digital signature of the
signed resource data is valid, using the public key of the target
resource certificate, and also validating the resource certificate in
the context of the RPKI, using the path validation process.
There are two inputs to the validation algortihm:
1. A trust anchor
2. A certificate to be validated
The algorithm is initialized with two new variables for use in the
RPKI: Verified Resource Set-IP (VRS-IP) and Verified Resource Set-AS
(VRS-AS). These sets are used to track the set of INRs (IP address
space and AS numbers) that are considered valid for each CA
certificate. The VRS-IP and VRS-AS sets are initially set to the IP
Address Delegation and AS Identifier Delegation values, respectively,
from the trust anchor used to perform validation.
This path validation algorithm verifies, among other things, that a
prospective certification path (a sequence of n certificates)
satisfies the following conditions:
a. for all 'x' in {1, ..., n-1}, the subject of certificate 'x' is
the issuer of certificate ('x' + 1);
b. certificate '1' is issued by a trust anchor;
c. certificate 'n' is the certificate to be validated; and
d. for all 'x' in {1, ..., n}, certificate 'x' is valid.
Certificate validation requires verifying that all of the following
conditions hold, in addition to the certification path validation
criteria specified in Section 6 of [RFC5280].
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1. The signature of certificate x (x>1) is verified using the public
key of the issuer's certificate (x-1), using the signature
algorithm specified for that public key (in certificate x-1).
2. The current time lies within the interval defined by the
NotBefore and NotAfter values in the Validity field of
certificate x.
3. The Version, Issuer, and Subject fields of certificate x satisfy
the constraints established in Sections 4.1 to 4.7 of RFC 6487.
4. If certificate x uses the Certificate Policy defined in
Section 4.8.9 of [RFC6487], then the certificate MUST contain all
extensions defined in Section 4.8 of [RFC6487] that must be
present. The value(s) for each of these extensions MUST satisfy
the constraints established for each extension in the respective
sections. Any extension not thus identified MUST NOT appear in
certificate x.
5. If certificate x uses the Certificate Policy defined in
Section 4.2.4.1 [RFC8360], then all extensions defined in
Section 4.8 of [RFC6487], except Sections 4.8.9, 4.8.10, and
4.8.11 MUST be present. The certificate MUST contain an
extension as defined in Sections 4.2.4.2 or 4.2.4.3 [RFC8360], or
both. The value(s) for each of these extensions MUST satisfy the
constraints established for each extension in the respective
sections. Any extension not thus identified MUST NOT appear in
certificate x.
6. Certificate x MUST NOT have been revoked, i.e., it MUST NOT
appear on a Certificate Revocation List (CRL) issued by the CA
represented by certificate x-1.
7. Compute the VRS-IP and VRS-AS set values as indicated below:
* If the IP Address Delegation extension is present in
certificate x and x=1, set the VRS-IP to the resources found
in this extension.
* If the IP Address Delegation extension is present in
certificate x and x>1, set the VRS-IP to the intersection of
the resources between this extension and the value of the VRS-
IP computed for certificate x-1.
* If the IP Address Delegation extension is absent in
certificate x, set the VRS-IP to NULL.
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* If the IP Address Delegation extension is present in
certificate x and x=1, set the VRS-IP to the resources found
in this extension.
* If the AS Identifier Delegation extension is present in
certificate x and x>1, set the VRS-AS to the intersection of
the resources between this extension and the value of the VRS-
AS computed for certificate x-1.
* If the AS Identifier Delegation extension is absent in
certificate x, set the VRS-AS to NULL.
8. If there is any difference in resources in the VRS-IP and the IP
Address Delegation extension on certificate x, or the VRS-AS and
the AS Identifier Delegation extension on certificate x, then a
warning listing the overclaiming resources for certificate x
SHOULD be issued.
These rules allow a CA certificate to contain resources that are not
present in (all of) the certificates along the path from the trust
anchor to the CA certificate. If none of the resources in the CA
certificate are present in all certificates along the path, no
subordinate certificates could be valid. However, the certificate is
not immediately rejected as this may be a transient condition. Not
immediately rejecting the certificate does not result in a security
problem because the associated VRS sets accurately reflect the
resources validly associated with the certificate in question.
4.2. Updates to Section 9
Section 9 "Operational Considerations for Profile Agility" is
removed.
5. Implementation status - RFC EDITOR: REMOVE BEFORE PUBLICATION
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in RFC7942. The
description of implementations in this section is intended to assist
the IETF in its decision processes in progressing drafts to RFCs.
Please note that the listing of any individual implementation here
does not imply endorsement by the IETF. Furthermore, no effort has
been spent to verify the information presented here that was supplied
by IETF contributors. This is not intended as, and must not be
construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
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As of today these changesets have been produced for commonly used
Relying Party implementations:
* NLnet Labs Routinator [routinator]
* OpenBSD rpki-client [rpkiclient]
* FORT Validator [fort]
The 'public' OpenSSL X509v3_addr_validate_path() and
X509v3_asid_validate_path() interfaces do not read the Policy OIDs.
Also, these interfaces are not referenced outside OpenSSL itself:
[codesearch] and [github].
At the time of writing there are zero (0) certificates in the RPKI
carrying the extensions and policy defined in [RFC8360].
6. Security Considerations
The authors believe that the revised validation algortihm introduces
no new security vulnerabilities into the RPKI, because it cannot lead
to any ROA and/or router certificates to be accepted if they contain
resources that are not held by the issuer.
7. IANA Considerations
IANA is requested to reference this document in the "SMI Security for
PKIX Certificate Policies" registry at:
* id-cp-ipAddr-asNumber-v2
IANA is requested to reference this document in the "SMI Security for
PKIX Certificate Extensions" registry at:
* id-pe-ipAddrBlocks-v2
* id-pe-autonomousSysIds-v2
IANA is requested to reference this document in the "SMI Security for
PKIX Module Identifier" registry at:
* id-mod-ip-addr-and-as-ident-v2
* id-mod-ip-addr-and-as-ident-2v2
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8. Acknowledgements
The authors would like to thank Tim Bruijnzeels, Mikael Abrahamsson,
Nick Hilliard, and Peter Peele for their helpful review of this
document.
9. References
9.1. 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>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
[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>.
[RFC6487] Huston, G., Michaelson, G., and R. Loomans, "A Profile for
X.509 PKIX Resource Certificates", RFC 6487,
DOI 10.17487/RFC6487, February 2012,
<https://www.rfc-editor.org/info/rfc6487>.
[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>.
[RFC8360] Huston, G., Michaelson, G., Martinez, C., Bruijnzeels, T.,
Newton, A., and D. Shaw, "Resource Public Key
Infrastructure (RPKI) Validation Reconsidered", RFC 8360,
DOI 10.17487/RFC8360, April 2018,
<https://www.rfc-editor.org/info/rfc8360>.
9.2. Informative References
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[codesearch]
Debian, "Debian Codesearch", February 2021,
<https://codesearch.debian.net/
search?q=X509v3_addr_validate_path&literal=1>.
[fort] Snijders, J., "Harmonize RFC 8360 and RFC 6487 in FORT",
February 2021, <https://github.com/job/FORT-
validator/commit/
ff5f4b9313d5c553fa13bae427acb69665977727>.
[github] Github, "Github Search", February 2021,
<https://github.com/
search?q=X509v3_addr_validate_path&type=commits>.
[Report] Snijders, J., "[routing-wg] RFC 8360 should be the default
(Was: RPKI Outage Post-Mortem)", January 2021,
<https://www.ripe.net/ripe/mail/archives/routing-
wg/2021-January/004220.html>.
[routinator]
Snijders, J., "Harmonize RFC 8360 and RFC 6487 in rpki-
rs", February 2021, <https://github.com/job/rpki-
rs/commit/d9fa8c72cf83ed6f25e4420eaaa9054078f15bc3>.
[rpkiclient]
Jeker, C., "rpki-client check IP and ASnum coverage only
on ROAs", January 2021,
<https://marc.info/?l=openbsd-tech&m=161011710120123&w=2>.
Authors' Addresses
Job Snijders
Fastly
Amsterdam
Netherlands
Email: job@fastly.com
Ben Maddison
Workonline
Cape-Town
South Africa
Email: benm@workonline.africa
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