draft-ietf-ace-oauth-params-07.txt   draft-ietf-ace-oauth-params-08.txt 
ACE Working Group L. Seitz ACE Working Group L. Seitz
Internet-Draft Combitech Internet-Draft Combitech
Intended status: Standards Track December 17, 2019 Intended status: Standards Track December 21, 2019
Expires: June 19, 2020 Expires: June 23, 2020
Additional OAuth Parameters for Authorization in Constrained Additional OAuth Parameters for Authorization in Constrained
Environments (ACE) Environments (ACE)
draft-ietf-ace-oauth-params-07 draft-ietf-ace-oauth-params-08
Abstract Abstract
This specification defines new parameters for the OAuth 2.0 token and This specification defines new parameters for the OAuth 2.0 token and
introspection endpoints when used with the framework for introspection endpoints when used with the framework for
authentication and authorization for constrained environments (ACE). authentication and authorization for constrained environments (ACE).
These are used to express the proof-of-possession key the client These are used to express the proof-of-possession key the client
whishes to use, the proof-of-possession key that the AS has selected, whishes to use, the proof-of-possession key that the AS has selected,
and the key the RS should use to authenticate to the client. and the key the RS should use to authenticate to the client.
skipping to change at page 1, line 36 skipping to change at page 1, line 36
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Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Parameters for the Token Endpoint . . . . . . . . . . . . . . 3 3. Parameters for the Token Endpoint . . . . . . . . . . . . . . 3
3.1. Client-to-AS Request . . . . . . . . . . . . . . . . . . 3 3.1. Client-to-AS Request . . . . . . . . . . . . . . . . . . 3
3.2. AS-to-Client Response . . . . . . . . . . . . . . . . . . 4 3.2. AS-to-Client Response . . . . . . . . . . . . . . . . . . 4
3.3. The Resource Server Confirmation Claim . . . . . . . . . 5 3.3. The Resource Server Confirmation Claim . . . . . . . . . 6
4. Parameters for the Introspection Endpoint . . . . . . . . . . 6 4. Parameters for the Introspection Endpoint . . . . . . . . . . 6
4.1. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 6 4.1. AS-to-RS Response . . . . . . . . . . . . . . . . . . . . 6
5. Confirmation Method Parameters . . . . . . . . . . . . . . . 7 5. Confirmation Method Parameters . . . . . . . . . . . . . . . 7
6. CBOR Mappings . . . . . . . . . . . . . . . . . . . . . . . . 8 6. CBOR Mappings . . . . . . . . . . . . . . . . . . . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 9 8. Privacy Considerations . . . . . . . . . . . . . . . . . . . 9
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9.1. JSON Web Token Claims . . . . . . . . . . . . . . . . . . 9 9.1. JSON Web Token Claims . . . . . . . . . . . . . . . . . . 9
9.2. CBOR Web Token Claims . . . . . . . . . . . . . . . . . . 9 9.2. CBOR Web Token Claims . . . . . . . . . . . . . . . . . . 9
9.3. OAuth Parameter Registration . . . . . . . . . . . . . . 9 9.3. OAuth Parameter Registration . . . . . . . . . . . . . . 9
9.4. OAuth Introspection Response Parameter Registration . . . 10 9.4. OAuth Introspection Response Parameter Registration . . . 10
9.5. OAuth Parameters CBOR Mappings Registraton . . . . . . . 10 9.5. OAuth Parameters CBOR Mappings Registraton . . . . . . . 10
9.6. OAuth Token Introspection Response CBOR Mappings 9.6. OAuth Token Introspection Response CBOR Mappings
Registration . . . . . . . . . . . . . . . . . . . . . . 11 Registration . . . . . . . . . . . . . . . . . . . . . . 11
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
11.1. Normative References . . . . . . . . . . . . . . . . . . 11 11.1. Normative References . . . . . . . . . . . . . . . . . . 11
11.2. Informative References . . . . . . . . . . . . . . . . . 12 11.2. Informative References . . . . . . . . . . . . . . . . . 12
Appendix A. Overlap with OAuth work . . . . . . . . . . . . . . 12 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 12
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
The Authentication and Authorization for Constrained Environments The Authentication and Authorization for Constrained Environments
(ACE) specification [I-D.ietf-ace-oauth-authz] requires some new (ACE) specification [I-D.ietf-ace-oauth-authz] requires some new
parameters for interactions with the OAuth 2.0 [RFC6749] token and parameters for interactions with the OAuth 2.0 [RFC6749] token and
introspection endpoints, as well as some new claims to be used in introspection endpoints, as well as some new claims to be used in
access tokens. These parameters and claims can also be used in other access tokens. These parameters and claims can also be used in other
contexts, and may need to be updated to align them with ongoing OAuth contexts and have therefore been put into a dedicated document, to
work. Therefore, these parameters and claims have been put into a facilitate their use in a manner independent of
dedicated document, to facilitate their use and any potential updates [I-D.ietf-ace-oauth-authz].
in a manner independent of [I-D.ietf-ace-oauth-authz].
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Readers are assumed to be familiar with the terminology from Readers are assumed to be familiar with the terminology from
skipping to change at page 3, line 44 skipping to change at page 3, line 38
containing a symmetric key value in the 'req_cnf' field, since the containing a symmetric key value in the 'req_cnf' field, since the
AS is expected to be able to generate better symmetric keys than a AS is expected to be able to generate better symmetric keys than a
constrained client. The AS MUST verify that the client really is constrained client. The AS MUST verify that the client really is
in possession of the corresponding key. Values of this parameter in possession of the corresponding key. Values of this parameter
follow the syntax of the "cnf" claim from section 3.1 of follow the syntax of the "cnf" claim from section 3.1 of
[I-D.ietf-ace-cwt-proof-of-possession]. [I-D.ietf-ace-cwt-proof-of-possession].
Figure 1 shows a request for an access token using the "req_cnf" Figure 1 shows a request for an access token using the "req_cnf"
parameter to request a specific public key as proof-of-possession parameter to request a specific public key as proof-of-possession
key. The content is displayed in CBOR diagnostic notation, without key. The content is displayed in CBOR diagnostic notation, without
abbreviations for better readability. abbreviations and with linebreaks for better readability.
Header: POST (Code=0.02) Header: POST (Code=0.02)
Uri-Host: "as.example.com" Uri-Host: "as.example.com"
Uri-Path: "token" Uri-Path: "token"
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"req_cnf" : { "req_cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "EC", "kty" : "EC",
"kid" : h'11', "kid" : h'11',
"crv" : "P-256", "crv" : "P-256",
"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8', "x" : h'BAC5B11CAD8F99F9C72B05CF4B9E26D24
"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4' 4DC189F745228255A219A86D6A09EFF',
"y" : h'20138BF82DC1B6D562BE0FA54AB7804A3
A64B6D72CCFED6B6FB6ED28BBFC117E'
} }
} }
} }
Figure 1: Example request for an access token bound to an asymmetric Figure 1: Example request for an access token bound to an asymmetric
key. key.
3.2. AS-to-Client Response 3.2. AS-to-Client Response
This document defines the following additional parameters for an AS This document defines the following additional parameters for an AS
skipping to change at page 5, line 9 skipping to change at page 5, line 12
[I-D.ietf-ace-cwt-proof-of-possession]. See Section 5 for [I-D.ietf-ace-cwt-proof-of-possession]. See Section 5 for
additional discussion of the usage of this parameter. additional discussion of the usage of this parameter.
Figure 2 shows an AS response containing a token and a "cnf" Figure 2 shows an AS response containing a token and a "cnf"
parameter with a symmetric proof-of-possession key. parameter with a symmetric proof-of-possession key.
Header: Created (Code=2.01) Header: Created (Code=2.01)
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"access_token" : b64'SlAV32hkKG ... "access_token" : h'4A5015DF686428 ...
(remainder of CWT omitted for brevity; (remainder of CWT omitted for brevity;
CWT contains COSE_Key in the "cnf" claim)', CWT contains COSE_Key in the "cnf" claim)',
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "Symmetric", "kty" : "Symmetric",
"kid" : b64'39Gqlw', "kid" : h'DFD1AA97',
"k" : b64'hJtXhkV8FJG+Onbc6mxCcQh' "k" : h'849B5786457C1491BE3A76DCEA6C427108'
} }
} }
} }
Figure 2: Example AS response with an access token bound to a Figure 2: Example AS response with an access token bound to a
symmetric key. symmetric key.
Figure 3 shows an AS response containing a token bound to a Figure 3 shows an AS response containing a token bound to a
previously requested asymmetric proof-of-possession key (not shown) previously requested asymmetric proof-of-possession key (not shown)
and a "rs_cnf" parameter containing the public key of the RS. and a "rs_cnf" parameter containing the public key of the RS.
Header: Created (Code=2.01) Header: Created (Code=2.01)
Content-Format: "application/ace+cbor" Content-Format: "application/ace+cbor"
Payload: Payload:
{ {
"access_token" : b64'0INDoQEKoQVNKkXfb7xaWqMTf6 ... "access_token" : h'D08343A1010AA1054D2A45DF6FBC5A5A ...
(remainder of CWT omitted for brevity; (remainder of CWT omitted for brevity;
CWT contains COSE_Key in the "cnf" claim)', CWT contains COSE_Key in the "cnf" claim)',
"rs_cnf" : { "rs_cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "EC", "kty" : "EC",
"kid" : h'12', "kid" : h'12',
"crv" : "P-256", "crv" : "P-256",
"x" : b64'vO5+qsFi+R5vMw9XcSEeIguLVGyWWJsKxK0P0kx34fE', "x" : h'BCEE7EAAC162F91E6F330F5771211E220
"y" : b64'xkezjFXvu8TmLmUXIPAC1ddbLgwCzRMm5mK8oiK5BBY' B8B546C96589B0AC4AD0FD24C77E1F1',
"y" : h'C647B38C55EFBBC4E62E651720F002D5D
75B2E0C02CD1326E662BCA222B90416'
} }
} }
} }
Figure 3: Example AS response, including the RS's public key. Figure 3: Example AS response, including the RS's public key.
3.3. The Resource Server Confirmation Claim 3.3. The Resource Server Confirmation Claim
If the AS needs to convey a hint to the RS about which key it should If the AS needs to convey a hint to the RS about which key it should
use to authenticate towards the client, this specification defines use to authenticate towards the client, this specification defines
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Payload: Payload:
{ {
"active" : true, "active" : true,
"scope" : "read", "scope" : "read",
"aud" : "tempSensor4711", "aud" : "tempSensor4711",
"cnf" : { "cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "EC", "kty" : "EC",
"kid" : h'11', "kid" : h'11',
"crv" : "P-256", "crv" : "P-256",
"x" : b64'usWxHK2PmfnHKwXPS54m0kTcGJ90UiglWiGahtagnv8', "x" : h'BAC5B11CAD8F99F9C72B05CF4B9E26D24
"y" : b64'IBOL+C3BttVivg+lSreASjpkttcsz+1rb7btKLv8EX4' 4DC189F745228255A219A86D6A09EFF',
"y" : h'20138BF82DC1B6D562BE0FA54AB7804A3
A64B6D72CCFED6B6FB6ED28BBFC117E'
} }
}, },
"rs_cnf" : { "rs_cnf" : {
"COSE_Key" : { "COSE_Key" : {
"kty" : "EC", "kty" : "EC",
"kid" : h'12', "kid" : h'12',
"crv" : "P-256", "crv" : "P-256",
"x" : b64'vO5+qsFi+R5vMw9XcSEeIguLVGyWWJsKxK0P0kx34fE', "x" : h'BCEE7EAAC162F91E6F330F5771211E220
"y" : b64'xkezjFXvu8TmLmUXIPAC1ddbLgwCzRMm5mK8oiK5BBY' B8B546C96589B0AC4AD0FD24C77E1F1',
"y" : h'C647B38C55EFBBC4E62E651720F002D5D
75B2E0C02CD1326E662BCA222B90416'
} }
} }
} }
Figure 4: Example introspection response. Figure 4: Example introspection response.
5. Confirmation Method Parameters 5. Confirmation Method Parameters
The confirmation method parameters are used as follows: The confirmation method parameters are used as follows:
skipping to change at page 11, line 42 skipping to change at page 11, line 42
[I-D.ietf-ace-cwt-proof-of-possession] [I-D.ietf-ace-cwt-proof-of-possession]
Jones, M., Seitz, L., Selander, G., Erdtman, S., and H. Jones, M., Seitz, L., Selander, G., Erdtman, S., and H.
Tschofenig, "Proof-of-Possession Key Semantics for CBOR Tschofenig, "Proof-of-Possession Key Semantics for CBOR
Web Tokens (CWTs)", draft-ietf-ace-cwt-proof-of- Web Tokens (CWTs)", draft-ietf-ace-cwt-proof-of-
possession-11 (work in progress), October 2019. possession-11 (work in progress), October 2019.
[I-D.ietf-ace-oauth-authz] [I-D.ietf-ace-oauth-authz]
Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and Seitz, L., Selander, G., Wahlstroem, E., Erdtman, S., and
H. Tschofenig, "Authentication and Authorization for H. Tschofenig, "Authentication and Authorization for
Constrained Environments (ACE) using the OAuth 2.0 Constrained Environments (ACE) using the OAuth 2.0
Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-27 Framework (ACE-OAuth)", draft-ietf-ace-oauth-authz-29
(work in progress), November 2019. (work in progress), December 2019.
[IANA.CborWebTokenClaims] [IANA.CborWebTokenClaims]
IANA, "CBOR Web Token (CWT) Claims", IANA, "CBOR Web Token (CWT) Claims",
<https://www.iana.org/assignments/cwt/cwt.xhtml#claims- <https://www.iana.org/assignments/cwt/cwt.xhtml#claims-
registry>. registry>.
[IANA.JsonWebTokenClaims] [IANA.JsonWebTokenClaims]
IANA, "JSON Web Token Claims", IANA, "JSON Web Token Claims",
<https://www.iana.org/assignments/jwt/jwt.xhtml#claims>. <https://www.iana.org/assignments/jwt/jwt.xhtml#claims>.
skipping to change at page 12, line 30 skipping to change at page 12, line 30
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012, RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/info/rfc6749>. <https://www.rfc-editor.org/info/rfc6749>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
11.2. Informative References 11.2. Informative References
[I-D.ietf-oauth-pop-key-distribution]
Bradley, J., Hunt, P., Jones, M., Tschofenig, H., and M.
Meszaros, "OAuth 2.0 Proof-of-Possession: Authorization
Server to Client Key Distribution", draft-ietf-oauth-pop-
key-distribution-07 (work in progress), March 2019.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014, DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>. <https://www.rfc-editor.org/info/rfc7252>.
Appendix A. Overlap with OAuth work
This document overlaps with draft work from OAuth on proof-of-
possesion keys [I-D.ietf-oauth-pop-key-distribution].
The OAuth draft specifies the use of "req_cnf" and "cnf" for
requesting proof-of-possession tokens and indicating the key that the
AS has selected. It it was initially deemed that the work at OAuth
had been discontinued and therefore equivalent functionality was
defined here. Work in OAuth has since resumed, but it is lagging
behind the planned milestones of the ACE working group. We have
therefore split this work out into a separate document so that it can
later be updated or obsoleted to align it with the final result of
the OAuth work, without affecting [I-D.ietf-ace-oauth-authz].
Author's Address Author's Address
Ludwig Seitz Ludwig Seitz
Combitech Combitech
Djaeknegatan 31 Djaeknegatan 31
Malmoe 211 35 Malmoe 211 35
Sweden Sweden
Email: ludwig.seitz@combitech.se Email: ludwig.seitz@combitech.se
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