SIDROPS
Internet Engineering Task Force (IETF) J. Snijders
Internet-Draft
Request for Comments: 9674 Fastly
Updates: 8182 (if approved) 2 October November 2024
Intended status:
Category: Standards Track
Expires: 5 April 2025
ISSN: 2070-1721
Same-Origin Policy for the RPKI Repository Delta Protocol (RRDP)
draft-ietf-sidrops-rrdp-same-origin-04
Abstract
This document describes a Same-Origin Policy (SOP) requirement for
RPKI
Resource Public Key Infrastructure (RPKI) Repository Delta Protocol
(RRDP) servers and clients. Application of a SOP in RRDP client/server client/
server communication isolates resources such as Delta and Snapshot
files from different Repository Servers, reducing possible attack
vectors. This document updates RFC 8182.
Status of This Memo
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This Internet-Draft will expire on 5 April 2025.
https://www.rfc-editor.org/info/rfc9674.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Implications of cross-origin resource requests Cross-Origin Resource Requests in RRDP . . . 3
3. Changes to RFC 8182 . . . . . . . . . . . . . . . . . . . . . 3
3.1. New Requirements for RRDP Repository Servers . . . . . . 3
3.2. New Requirements for Relying Parties using Using RRDP . . . . . 3
4. Deployability in the Internet's current Current RPKI . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Appendix A.
Acknowledgements . . . . . . . . . . . . . . . . . . 6
Appendix B. Implementation status . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
This document specifies a Same-origin policy Same-Origin Policy (SOP) requirement for
RPKI Repository Delta Protocol (RRDP) servers and clients. The SOP
concept is a security mechanism to restrict how a document loaded
from one origin can cause interaction with resources from another
origin. See [RFC6454] for an overview of the concept of an "origin".
Application of a SOP in RRDP client/server communication isolates
resources such as Delta and Snapshot files from different Repository
Servers, reducing possible attack vectors. Another way to avoid
undesirable implications (as described in Section 2) would be for a
future version of the RRDP protocol to use relative URIs instead of absolute URIs.
This document updates [RFC8182].
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. Implications of cross-origin resource requests Cross-Origin Resource Requests in RRDP
The first RRDP protocol specification did not explicitly disallow
'cross-origin' 'cross-
origin' URI references from the Update Notification file
(Section 3.5.1 of [RFC8182]) towards Delta (Section 3.5.3 of
[RFC8182]) and Snapshot (Section 3.5.2 of [RFC8182]) files, and it
was silent on the topic of HTTP Redirection (Section 15.4 of
[RFC9110]).
The implication of cross-origin references in Update Notification
files is that one Repository Server can reference RRDP resources on
another Repository Server and in doing so inappropriately increase
the resource consumption for both RRDP clients and the referenced
Repository Server. An adversary could also employ cross-origin HTTP
Redirects towards other Repository Servers, causing similar
undesirable behavior.
3. Changes to RFC 8182
To overcome the aforementioned issue described in Section 2, RRDP Repository Servers
and Clients MUST apply a Same-Origin Policy to both the URIs
referenced in an Update Notification File and any HTTP Redirects.
3.1. New Requirements for RRDP Repository Servers
The following checklist items are added to Section 3.5.1.3 of
[RFC8182]:
NEW
| * The "uri" attribute in the snapshot element and optional delta
| elements MUST be part of the same origin (i.e., represent the
| same principal), meaning referenced URIs MUST have the same
| scheme, host, and port as the URI for the Update Notification
| File specified in the referring RRDP SIA AccessDescription.
|
| * The Repository Server MUST NOT respond with HTTP Redirects
| towards locations with an origin different from the origin of
| the Update Notification File specified in the referring RRDP
| SIA AccessDescription.
3.2. New Requirements for Relying Parties using Using RRDP
The following adds to Section 3.4.1 of [RFC8182]:
NEW
| * The Relying Party MUST verify whether the "uri" attributes in
| the Update Notification File are of the same origin as the
| Update Notification File itself. If this verification fails,
| the file MUST be rejected and RRDP cannot be used, used; see
| Section 3.4.5 of [RFC8182] for considerations. Implementations
| SHOULD log a
| message when cross-origin referrals are detected.
|
| * The Relying Party MUST NOT follow HTTP Redirection following that results
| from attempts to download Update Notification, Delta, and
| Snapshot files if the target origin is different from the
| origin of the Update Notification File specified in the
| referring RRDP SIA AccessDescription. If this verification
| fails, the RRDP session MUST be rejected and RRDP cannot be
| used, used; see Section 3.4.5 of [RFC8182] for considerations.
| Implementations
| SHOULD log a message when cross-origin
| redirects are detected.
4. Deployability in the Internet's current Current RPKI
Analysing
Analyzing the [rpkiviews] archives for the period from April to
September 2024, only one RRDP server (reached following the TALs Trust
Anchor Locators (TALs) of the five Regional Internet Registries)
employed a same-origin HTTP redirect. In the period October 2021 -
October 2024 no RRDP Repository Servers were observed which that employed
cross-origin URIs in Update Notification Files.
This means that imposing a requirement for the application of a Same-
Origin Policy does not cause any existing commonly-used commonly used RRDP
Repository Server operations to become non-compliant.
5. Security Considerations
This document addresses an oversight in the original RRDP protocol
specification: cross-origin Cross-origin requests are detrimental as they allow
one repository operator to increase resource consumption for other
repository operators and RRDP clients.
6. IANA Considerations
No
This document has no IANA actions required. actions.
7. References
7.1. 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>.
[RFC6454] Barth, A., "The Web Origin Concept", RFC 6454,
DOI 10.17487/RFC6454, December 2011,
<https://www.rfc-editor.org/info/rfc6454>.
[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>.
[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/info/rfc9110>.
7.2. Informative References
[FORT-validator]
Leiva, A., "FORT validator",
<https://fortproject.net/en/validator>.
[Routinator]
NLNet Labs, "Routinator",
<https://github.com/NLnetLabs/routinator/>.
[rpki-client]
Jeker, C., Snijders, J., Dzonsons, K., and T. Buehler,
"rpki-client", <https://www.rpki-client.org/>.
[rpki-prover]
Puzanov, M., "rpki-prover",
<https://github.com/lolepezy/rpki-prover>.
[rpkiviews]
Snijders, J., "rpkiviews", October 2024,
<http://www.rpkiviews.org/>.
Appendix A. <https://www.rpkiviews.org>.
Acknowledgements
The author wishes to thank Theo Buehler, Claudio Jeker, Alberto
Leiva, Tim Bruijnzeels, Ties de Kock, Martin Hoffmann, and Mikhail
Puzanov for their helpful feedback, comments, and implementation
work. The author wishes to thank Keyur Patel, Meral Shirazipour,
Niclas Comstedt, Dan Harkins, Erik Kline, Roman Danyliw, and Éric
Vyncke for their review.
Appendix B. Implementation status
This section is to be removed before publishing as an RFC.
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 RFC 7942.
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.
According to RFC 7942, "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
* OpenBSD's [rpki-client]
* Mikhail Puzanov's [rpki-prover]
* FORT project's [FORT-validator]
* NLNet Labs' [Routinator]
Author's Address
Job Snijders
Fastly
Amsterdam
Netherlands
Email: job@fastly.com