Internet DRAFT - draft-ietf-cdni-interfaces-https-delegation
draft-ietf-cdni-interfaces-https-delegation
Content Delivery Networks Interconnection F. Fieau, Ed.
Internet-Draft E. Stephan
Intended status: Standards Track Orange
Expires: 17 June 2023 S. Mishra
Verizon
14 December 2022
CDNI extensions for HTTPS delegation
draft-ietf-cdni-interfaces-https-delegation-13
Abstract
This document defines metadata objects to support delegating the
delivery of HTTPS content between two or more interconnected CDNs.
Specifically, this document defines CDNI Metadata interface objects
to enable delegation of X.509 certificates leveraging delegation
schemes defined in RFC9115. RFC 9115 allows delegating entities to
remain in full control of the delegation and be able to revoke it any
time and avoids the need to share private cryptographic key material
between the involved entities.
About This Document
This note is to be removed before publishing as an RFC.
Status information for this document may be found at
https://datatracker.ietf.org/doc/draft-ietf-cdni-interfaces-https-
delegation/.
Discussion of this document takes place on the Content Delivery
Networks Interconnection Working Group mailing list
(mailto:cdni@ietf.org), which is archived at
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Source for this draft and an issue tracker can be found at
https://github.com/FredericFi/cdni-wg.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Advertising Delegation Metadata for CDNI through FCI . . . . 3
3. ACME Delegation Metadata for CDNI . . . . . . . . . . . . . 4
3.1. ACMEDelegationMethod Object . . . . . . . . . . . . . . . 6
3.1.1. Examples . . . . . . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . 7
4.1. CDNI MI ACMEDelegationMethod Payload Type . . . . . . . . 8
5. Security considerations . . . . . . . . . . . . . . . . . . . 8
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
6.1. Normative References . . . . . . . . . . . . . . . . . . 8
6.2. Informative References . . . . . . . . . . . . . . . . . 9
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Content delivery over HTTPS using two or more cooperating Content
Delivery Networks (CDNs) along the path requires credential
management, specifically when DNS-based redirection is used. In such
cases, an upstream CDN (uCDN) needs to delegate its credentials to a
downstream (dCDN) for content delivery.
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[RFC9115] defines delegation methods that allow a uCDN on behalf of
the content provider, the holder of the domain, to generate on-demand
an X.509 certificate that binds the designated domain name with a
key-pair owned by the dCDN. For further details, please refer to
Section 1 of [RFC9115] and Section 5.1.2.1 of [RFC9115].
This document defines CDNI Metadata to make use of HTTPS delegation
between a uCDN and a dCDN based on the mechanism specified in
[RFC9115]. Furthermore, it adds a delegation method to the "CDNI
Payload Types" IANA registry.
Section 1.1 defines terminology used in this document. Section 2
presents delegation metadata for the FCI interface. Section 3
addresses the metadata for handling HTTPS delegation with the
Metadata Interface. Section 4 addresses IANA registry for delegation
methods. Section 5 covers the security considerations.
1.1. Terminology
This document uses terminology from CDNI framework documents such as:
CDNI framework document [RFC7336], CDNI requirements [RFC7337] and
CDNI interface specifications documents: CDNI Metadata interface
[RFC8006] and CDNI Footprint and capabilities [RFC8008]. It also
uses terminology from Section 1.1 of [RFC8739].
2. Advertising Delegation Metadata for CDNI through FCI
The Footprint and Capabilities interface defined in [RFC8008] allows
a dCDN to send a FCI capability type object to a uCDN.
The FCI.Metadata object allows a dCDN to advertise the capabilities
regarding the supported delegation methods and their configuration.
The following is an example of the supported delegated methods
capability object for a dCDN implementing the ACME delegation method.
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{
"capabilities": [
{
"capability-type": "FCI.Metadata",
"capability-value": {
"metadata": [
"ACMEDelegationMethod",
"... Other supported delegation methods ..."
]
},
"footprints": [
"Footprint objects"
]
}
]
}
3. ACME Delegation Metadata for CDNI
When a uCDN delegates to a dCDN to deliver HTTPS traffic using DNS
Redirection [RFC7975], the dCDN must use a certificate bound to the
origin's name to successfully authenticate to the end-user (see also
Section 5.1.2.1 of [RFC9115]).
To that end, this section defines the AcmeDelegationMethod object
which describes metadata for using the ACME delegation interface
[RFC9115].
The ACMEDelegationMethod applies to both ACME STAR delegation, which
provides a delegation model based on short-term certificates with
automatic renewal Section 2.3.2 of [RFC9115], and non-STAR
delegation, which allows delegation between CDNs using long-term
certificates Section 2.3.3 of [RFC9115].
Figure 1 provides a high-level view of the combined CDNI and ACME
delegation message flows to obtain STAR certificate bound to the
origin's name.
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.----. .----. .----. .----.
|dCDN| |uCDN| | CP | | CA |
'-+--' '-+--' '--+-' '--+-'
| GET metadata | | |
+--------[CDNI]------>| | |
| 200 OK, metadata | | |
| (inc. dele config) | | |
|<-------[CDNI]-------+ | |
| | | |
| GET delegation | | |
+-----[ACME dele]---->| | |
| 200 OK, delegation | | |
| (inc. CSR template) | | |
|<----[ACME dele]-----+ | |
| | | |
+----. | | |
| | | | |
| create key pair and| | |
| CSR w/ delegated | | |
| name | | |
| | | | |
|<---' | | |
| | | |
| POST Order1 | | |
+-----[ACME dele]---->| | |
| | forward Order1 | |
| +-----[ACME dele]---->| |
| | | POST Order2 |
| | +-----[ACME STAR]----->|
| | | |
| | |<---authorizations--->|
| | | |
|<---wait issuance--->|<---wait issuance--->|<---wait issuance---->|
| |
| (unauthenticated) GET star-certificate |
+----------------------------------------------------------------->|
| certificate #1 |
|<-----------------------------------------------------------------+
| ... |
Figure 1: Example call-flow of STAR delegation in CDNI showing 2
levels of delegation
Section 3.1 defines the objects used for bootstrapping the ACME
delegation method between a uCDN and a delegate dCDN.
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3.1. ACMEDelegationMethod Object
The ACMEDelegationMethod object allows a uCDN to both define STAR and
non-STAR delegation depending on the delegation certificate validity.
The ACMEDelegationMethod object is defined with several properties
shown below.
* Property: acme-delegation
- Description: a URL pointing at an ACME delegation object,
either STAR or non-STAR, associated with the dCDN account on
the uCDN ACME server (see Section 2.3.1 of [RFC9115] for the
details).
- Type: Link object, according to Section 4.3.1 of [RFC8006]
- Mandatory-to-Specify: Yes
* Property: time-window
- Description: Validity period of the certificate. According to
Section 4.3.4 of [RFC8006], a TimeWindow object is defined by a
window "start" time, and a window "end" time of the window. In
case of STAR method, the "start" and "end" properties of the
window must be understood respectively as the start-date and
end-date of the certificate validity in Epoch time format. In
the case of the non-STAR method, the "start" and "end"
properties of the window must be understood respectively as the
notBefore and notAfter fields of the certificate.
- Type: TimeWindow
- Mandatory-to-Specify: Yes
* Property: lifetime
- Description: See Section 3.1.1 of [RFC8739]
- Type: Time, see Section 4.3.4 of [RFC8006]
- Mandatory-to-Specify: Yes, only if a STAR delegation method is
specified
* Property: lifetime-adjust
- Description: See Section 3.1.1 of [RFC8739]
- Type: Time
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- Mandatory-to-Specify: Yes, only if a STAR delegation method is
specified
3.1.1. Examples
The following example shows an ACMEDelegationMethod object for a
STAR-based ACME delegation.
{
"generic-metadata-type": "MI.ACMEDelegationMethod",
"generic-metadata-value": {
"acme-delegation": "https://acme.ucdn.example/delegation/ogfr",
"time-window": {
"start": 1665417434,
"end": 1665676634
},
"lifetime": 345600,
"lifetime-adjust": 259200
}
}
The example below shows an ACMEDelegationMethod object for a non-STAR
ACME delegation. The delegation object is defined as per Section 4.3
of [RFC8006].
{
"generic-metadata-type": "MI.ACMEDelegationMethod",
"generic-metadata-value": {
"acme-delegation": "https://acme.ucdn.example/delegation/wSi5",
"time-window": {
"start": 1570982234,
"end": 1665417434
}
}
}
4. IANA Considerations
This document requests the registration of the following entry under
the "CDNI Payload Types" registry:
+=========================+===============+
| Payload Type | Specification |
+=========================+===============+
| MI.ACMEDelegationMethod | RFCthis |
+-------------------------+---------------+
Table 1
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// RFC Editor: please replace RFCthis with the RFC number of this RFC
// and remove this note.
4.1. CDNI MI ACMEDelegationMethod Payload Type
Purpose: The purpose of this Payload Type is to distinguish
AcmeDelegationMethod MI objects (and any associated capability
advertisement)
Interface: MI/FCI
Encoding: See Section 3
5. Security considerations
The metadata object defined in this document does not introduce any
new security or privacy concerns over those already discussed in
[RFC9115], [RFC8006] and [RFC8008].
The reader is expected to understand the ACME delegation trust model
(Section 7.1 of [RFC9115]) and security goal (Section 7.3 of
[RFC9115]), in particular the criticality around the protection of
the user account associated with the delegation.
In addition, the requirements defined by CDNI Metadata and CDNI
Footprint and Capabilities regarding the integrity, (mutual)
authentication and confidentiality of the communication channel used
to transport the metadata object apply.
When TLS is used to achieve the above security objectives, the
general TLS usage guidance in [RFC9325] MUST be followed.
6. References
6.1. Normative References
[RFC8006] Niven-Jenkins, B., Murray, R., Caulfield, M., and K. Ma,
"Content Delivery Network Interconnection (CDNI)
Metadata", RFC 8006, DOI 10.17487/RFC8006, December 2016,
<https://www.rfc-editor.org/rfc/rfc8006>.
[RFC8008] Seedorf, J., Peterson, J., Previdi, S., van Brandenburg,
R., and K. Ma, "Content Delivery Network Interconnection
(CDNI) Request Routing: Footprint and Capabilities
Semantics", RFC 8008, DOI 10.17487/RFC8008, December 2016,
<https://www.rfc-editor.org/rfc/rfc8008>.
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[RFC8739] Sheffer, Y., Lopez, D., Gonzalez de Dios, O., Pastor
Perales, A., and T. Fossati, "Support for Short-Term,
Automatically Renewed (STAR) Certificates in the Automated
Certificate Management Environment (ACME)", RFC 8739,
DOI 10.17487/RFC8739, March 2020,
<https://www.rfc-editor.org/rfc/rfc8739>.
[RFC9115] Sheffer, Y., López, D., Pastor Perales, A., and T.
Fossati, "An Automatic Certificate Management Environment
(ACME) Profile for Generating Delegated Certificates",
RFC 9115, DOI 10.17487/RFC9115, September 2021,
<https://www.rfc-editor.org/rfc/rfc9115>.
[RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/rfc/rfc9325>.
6.2. Informative References
[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <https://www.rfc-editor.org/rfc/rfc7336>.
[RFC7337] Leung, K., Ed. and Y. Lee, Ed., "Content Distribution
Network Interconnection (CDNI) Requirements", RFC 7337,
DOI 10.17487/RFC7337, August 2014,
<https://www.rfc-editor.org/rfc/rfc7337>.
[RFC7975] Niven-Jenkins, B., Ed. and R. van Brandenburg, Ed.,
"Request Routing Redirection Interface for Content
Delivery Network (CDN) Interconnection", RFC 7975,
DOI 10.17487/RFC7975, October 2016,
<https://www.rfc-editor.org/rfc/rfc7975>.
Acknowledgments
We would like to thank authors of the [RFC9115], Antonio Augustin
Pastor Perales, Diego Lopez, Thomas Fossati and Yaron Sheffer.
Additionally, our gratitude to Thomas Fossati who participated in the
drafting, reviewing and giving his feedback in finalizing this
document. We also thank CDNI co-chair Kevin Ma for his continual
review and feedback during the development of this document.
Authors' Addresses
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Frédéric Fieau (editor)
Orange
40-48, avenue de la Republique
92320 Chatillon
France
Email: frederic.fieau@orange.com
Emile Stephan
Orange
2, avenue Pierre Marzin
22300 Lannion
France
Email: emile.stephan@orange.com
Sanjay Mishra
Verizon
13100 Columbia Pike
Silver Spring, MD 20904
United States of America
Email: sanjay.mishra@verizon.com
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