| Network Working Group | F. Fieau, Ed. |
| Internet-Draft | E. Stephan |
| Intended status: Standards Track | Orange |
| Expires: January 3, 2019 | S. Mishra |
| Verizon | |
| July 02, 2018 |
CDNI extensions for HTTPS delegation
draft-fieau-cdni-interfaces-https-delegation-04
The delivery of content over HTTPS involving multiple CDNs raises credential management issues. This document proposes extensions in CDNI Control and Metadata interfaces to setup HTTPS delegation from an Upstream CDN (uCDN) to a Downstream CDN (dCDN).
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Content delivery over HTTPS using one or more CDNs along the path requires credential management. This specifically applies when an entity delegates delivery of encrypted content to another trusted entity.
Several delegation methods are currently proposed within different IETF working groups (refer to [I-D.fieau-cdni-https-delegation] for an overview of delegation works ongoing at the IETF). They specify different methods for provisioning HTTPS delivery credentials.
This document extends the CDNI Metadata interface to setup HTTPS delegation between an upstream CDN (uCDN) and downstream CDN (dCDN). Furthermore, it includes a proposal of IANA registry to enable the adding of new methods in the future.
Section 2 is about terminology used in this document. Section 3 presents delegation methods specified at the IETF. Section 4 introduces delegation metadata in CDNI. Section 5 addresses the delegation methods objects. Section 6 describes simple data types. Section 7 is about an IANA registry for delegation methods. Section 8 raises the security issues.
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], CDNI Control interface / Triggers [RFC8007] and Logging interface [RFC7937].
There are currently I-D drafts proposed at the IETF to handle delegation of HTTPS delivery between entities, refer to [I-D.fieau-cdni-https-delegation].
Regading the existing delegation methods, this additional CDNI framework provides new requirements on the CDNI interfaces.
This document considers the following methods supporting HTTPS delegation. It may be used between two or more CDNs with applicable interface support following the CDNI framework, such as the CI/Triggers and Metadata Interface:
- Sub-certificates [I-D.ietf-tls-subcerts]
- Short-term certificates in ACME using STAR API [I-D.ietf-acme-star]
This section defines a CDNI extension to the current Metadata interface model that allows bootstrapping a delegation method between a uCDN and a delegate dCDN.
This document reuses PathMetadata object, as defined in [RFC8006], by adding a new "SecureDelegation" object containing a "supportedDelegationMethods" property.
This object will allow a uCDN delegating HTTPS delivery to a dCDN to indicate whether there is a delegation occurring on a PathMatch and which are the delegation methods that can be applied when the UA requests contents on the dCDN.
Property: supportedDelegationMethods
Example:
As an example, the PathMatch object can reference a path-metadata that points at the delegation information. Delegation metadata are added to PathMetaData object.
PathMatch:
{
"path-pattern": {
"pattern": "/movies/*",
"case-sensitive": true
},
"path-metadata": {
"type": "MI.PathMetadata",
"href": "https://metadata.ucdn.example/video.example.com/movies"
}
}
Below shows the PathMetaData Object related to /movie/* ( located at https://metadata.ucdn.example/video.example.com/movies )
PathMetadata:
{
"metadata": [
{
"generic-metadata-type": "MI.TimeWindowACL",
"generic-metadata-value": {
"times": [
"windows": [
{
"start": "1213948800",
"end": "1478047392"
}
],
"action": "allow",
}},
{
"generic-metadata-type": "MI.SecureDelegation"
"generic-metadata-type": {
"supportedDelegationMethods": [“MI.AcmeStarDelegationMethod”],
}
}
]
}
The existence of the "MI.SecureDelegation" object in a PathMetaData Object shall enable the use of one of the supported Methods, chosen by the delegate. The delegation method will be activated for the set of Path defined in the PathMatch. See next section for more details about delegation methods metadata specification.
This section defines the delegation methods objects metadata. Those metadata are related to the following aspects of a delegation:
This section defines the AcmeStarDelegationMethod object which describes metadata related to the use of Acme Star API presented in [I-D.ietf-acme-star]
As expressed in [I-D.ietf-acme-star] and [I-D.nir-saag-star], when an origin has set a delegation to a specific domain (i.e. dCDN), the dCDN should present to the end-user client, a short-term certificate bound to the master certificate.
Property: starproxy
Property: acmeserver
Property: credentialslocationuri
Property: periodicity
As an example, AcmeStarDelegationMethod object could express the Acme-Star delegation as the following:
AcmeStarDelegationMethod: {
"generic-metadata-type": "MI.AcmeStarDelegationMethod",
"generic-metadata-value": {
“starproxy”: “10.2.2.2”,
“acmeserver”: “10.2.3.3”,
"credentialslocationuri": “www.ucdn.com/credentials”,
"periodicity": 36000
}
}
This section defines the SubcertsDelegationMethod object which describes metadata related to the use of Subcerts as presented in [I-D.ietf-tls-subcerts]
As expressed in [I-D.ietf-tls-subcerts], when an origin has set a delegation to a specific domain (i.e. dCDN), the dCDN should present the Origin or uCDN certificate or "delegated_credential" during the TLS handshake to the end-user client application, instead of its own certificate.
Property: credentialsdelegatingentity
Property: credentialrecipiententity
Property: credentialslocationuri
Property: periodicity
As an example, when a uCDN has delegated HTTPS delivery to dCDN, a SubcertsDelegationMethod object can express the SubCerts delegation as the following:
SubcertsDelegationMethod: {
"generic-metadata-type": "MI.SubcertsDelegationMethod",
"generic-metadata-value": {
"credentialsdelegatingentity": “10.2.2.2”,
“credentialsrecepiententity”: “10.2.3.3”,
"credentialslocationuri": “www.ucdn.com/credentials”,
"periodicity": 36000
}
}
This section defines the LurkDelegationMethod object which describes metadata related to the use of LURK as defined in [I-D.mglt-lurk-tls].
Property: keyserver
As an example, when a uCDN has delegated HTTPS delivery to dCDN, a LurksDelegationMethod object can express the LURK delegation as the following:
LurkDelegationMethod: {
"generic-metadata-type": "MI.LurkDelegationMethod",
"generic-metadata-value": {
"keyserver": “10.2.2.2”,
}
}
This section describes the simple data types that are used for properties for objects in this document.
A time value expressed in seconds to indicate a periodicity.
Type: Integer
This document requests the registration of the following entries under the "CDNI Payload Types" registry hosted by IANA regarding “CDNI delegation”:
+----------------------------+---------------+ | Payload Type | Specification | +----------------------------+---------------+ | MI.SecureDelegation | TBD | | MI.AcmeStarDelegationMethod| TBD | | MI.SubCertDelegationMethod | TBD | | MI.LurkDelegationMethod | TBD | | ... | | +----------------------------+---------------+
Purpose: The purpose of this Payload Type is to distinguish SecureDelegation MI objects (and any associated capability advertisement)
Interface: MI/FCI
Encoding: see Section 5.1
Purpose: The purpose of this Payload Type is to distinguish AcmeStarDelegationMethod MI objects (and any associated capability advertisement)
Interface: MI/FCI
Encoding: see Section 5.1
Purpose: The purpose of this Payload Type is to distinguish SubcertsDelegationMethod MI objects (and any associated capability advertisement)
Interface: MI/FCI
Encoding: see Section 5.2
Extensions proposed here do not change Security Considerations as outlined in the CDNI Metadata and Footprint and Capabilities RFCs [RFC8006].
| [I-D.fieau-cdni-https-delegation] | Fieau, F., Emile, S. and S. Mishra, "HTTPS delegation in CDNI", Internet-Draft draft-fieau-cdni-https-delegation-02, July 2017. |
| [I-D.ietf-acme-star] | Sheffer, Y., Lopez, D., Dios, O., Pastor, A. and T. Fossati, "Support for Short-Term, Automatically-Renewed (STAR) Certificates in Automated Certificate Management Environment (ACME)", Internet-Draft draft-ietf-acme-star-03, March 2018. |
| [I-D.ietf-tls-subcerts] | Barnes, R., Iyengar, S., Sullivan, N. and E. Rescorla, "Delegated Credentials for TLS", Internet-Draft draft-ietf-tls-subcerts-00, October 2017. |
| [I-D.mglt-lurk-tls] | Migault, D., "LURK Protocol for TLS/DTLS1.2 version 1.0", Internet-Draft draft-mglt-lurk-tls-01, March 2017. |
| [I-D.nir-saag-star] | Nir, Y., Fossati, T., Sheffer, Y. and T. Eckert, "Considerations For Using Short Term Certificates", Internet-Draft draft-nir-saag-star-01, March 2018. |
| [I-D.reschke-http-oob-encoding] | Reschke, J. and S. Loreto, "'Out-Of-Band' Content Coding for HTTP", Internet-Draft draft-reschke-http-oob-encoding-12, June 2017. |