Internet DRAFT - draft-richer-oauth-httpsig
draft-richer-oauth-httpsig
OAUTH J. Richer, Ed.
Internet-Draft Bespoke Engineering
Intended status: Standards Track 21 June 2021
Expires: 23 December 2021
OAuth Proof of Possession Tokens with HTTP Message Signatures
draft-richer-oauth-httpsig-00
Abstract
This extension to the OAuth 2.0 authorization framework defines a
method for using HTTP Message Signatures to bind access tokens to
keys held by OAuth 2.0 clients.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 23 December 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. Token Response . . . . . . . . . . . . . . . . . . . . . . . 3
3. Presenting an HTTP Message Signature Bound Access Token . . . 3
4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . 5
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . 5
Appendix A. Document History . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The OAuth 2.0 framework provides methods for clients to get delegated
access tokens from an authorization server for accessing protected
resources. The access tokens at the center of OAuth 2.0 can be bound
to a variety of different mechanisms, including bearer tokens, mutual
TLS, or other presentation mechanisms.
Bearer tokens are simple to implement but also have the significant
security downside of allowing anyone who sees the access token to use
that token. This extension defines a token type that binds the token
to a presentation key known to the client. The client uses HTTP
Message Signatures (I-D.ietf-httpbis-message-signatures) to sign
requests using its key, thereby proving its right to present the
associated access token.
1.1. Terminology
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.
This document contains non-normative examples of partial and complete
HTTP messages, JSON structures, URLs, query components, keys, and
other elements. Some examples use a single trailing backslash '' to
indicate line wrapping for long values, as per [RFC8792]. The "\"
character and leading spaces on wrapped lines are not part of the
value.
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2. Token Response
When the client makes an access token request, the AS associates the
generated access token with the client's registered key from the
client's "jwks" or "jwks_uri" field. All presentations of this token
at any RS MUST contain an HTTP message signature as described in
Section 3.
A bound access token MUST have a "token_type" value of "httpsig".
The response MUST contain a "keyid" value which indicates the key the
client MUST use when presenting the access token Section 3. The
value of this "keyid" field MUST uniquely identify a key from the
client's registered key set by its "kid" value.
{
"access_token": "2340897.34j123-134uh2345n",
"token_type": "httpsig",
"keyid": "test-key-rsa-pss"
}
[[ Editor's note: while this document deals only with using a pre-
registered key, it would be possible to have different key binding
mechanisms, such as the client presenting an ephemeral key during the
token request or the AS generating and assigning a key alongside the
token. The WG needs to decide if this is in scope of this document
or not. The presentation mechanisms would be the same. ]]
3. Presenting an HTTP Message Signature Bound Access Token
The algorithm and key used for the HTTP Message Signature are derived
from the client's registered information. The key is taken from the
client's registered "jwks" or "jwks_uri" field, identified by the
"keyid" field of the token response Section 2. The signature
algorithm is determined by the "alg" field of the identified key,
following the method for JSON Web Algorithm selection described in
[I-D.ietf-httpbis-message-signatures].
The client MUST include the access token value in an "Authorization"
header using scheme "HTTPSig". Note that the scheme value "HTTPSig"
is not case sensitive.
Authorization: HTTPSig 2340897.34j123-134uh2345n
The client MUST include an HTTP Message Signature that covers, at
minimum:
* The request target of the RS being called
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* The "Host" header of the RS being called
* The "Authorization" header containing the access token value.
The signature parameters MUST include a "created" signature
parameter. The RS SHOULD use this field to ensure freshness of the
signed request, appropriate to the API being protected.
The client MUST NOT include an "alg" signature parameter, since the
algorithm is determined by the client's registered key. The client
MUST include the "keyid" signature parameter set to the value
returned in the token response Section 2.
In this example, the client has a key with the "kid" value of "test-
key-rsa-pss" which uses the JWA "alg" value of "PS512". The
signature input string is:
"@request-target": get /foo
"host": example.org
"authorization": HTTPSig 2340897.34j123-134uh2345n
"@signature-params": ("@request-target" "host" "authorization")\
;created=1618884475;keyid="test-key-rsa-pss"
This results in the following signed HTTP message, including the
access token.
GET /foo HTTP/1.1
Host: example.com
Date: Tue, 20 Apr 2021 02:07:55 GMT
Authorization: HTTPSig 2340897.34j123-134uh2345n
Signature-Input: sig1=("@request-target" "host" "authorization")\
;created=1618884475;keyid="test-key-rsa-pss"
Signature: sig1=:o+Fy/a6IIWhHwnMFhsHqfXEpheWGBMOU3pheT50zA8rL5F8Nur\
xBKAPylMGBWYCKH5Bd+TB0Co6vqANlXyOCM9Zr5c/UmR5WGex5/OgJJmfN7gOVOH5\
pB2Zxa233xsohfwo9liBlctukN5//E3F04rKjIkoeTFJiS+hMcOzn29esgFSEl4Jy\
oO5Q8snMIsC56ZAPYwU7rJis1Wvl6Y9/9tpW6gIn/SHwArhPQSAb0zZy6mCiw654n\
CaKw5NYJ9S0DZlnV4T7nJtdZsHOkddF6kH4WVka3ev0xONI5kYkEdR1Gw0VAE9thi\
p+3/aFoUVTJ/1J6JfehZpXqehwv3KNoQ==:
An RS receiving such a signed message and a bound access token MUST
verify the HTTP Message Signature as described in
[I-D.ietf-httpbis-message-signatures]. The RS MUST verify that all
required portions of the HTTP request are covered by the signature by
examining the contents of the signature parameters.
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[[ Editor's note: we should define confirmation methods for access
tokens here, including JWT values and introspection response values
to allow the RS to verify the signature w/o the client's registration
information. ]]
4. Acknowledgements
5. IANA Considerations
[[ TBD: register the token type and new parameters into their
appropriate registries, as well as the JWT and introspection
parameters. ]]
6. Security Considerations
[[ TBD: There are a lot of security considerations to add. ]]
All requests have to be over TLS or equivalent as per [BCP195].
7. Privacy Considerations
[[ TBD: There are a lot of privacy considerations to add. ]]
8. Normative References
[BCP195] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", May 2015,
<https://www.rfc-editor.org/info/bcp195>.
[I-D.ietf-httpbis-message-signatures]
Backman, A., Richer, J., and M. Sporny, "Signing HTTP
Messages", Work in Progress, Internet-Draft, draft-ietf-
httpbis-message-signatures-05, 8 June 2021,
<https://www.ietf.org/archive/id/draft-ietf-httpbis-
message-signatures-05.txt>.
[I-D.ietf-oauth-dpop]
Fett, D., Campbell, B., Bradley, J., Lodderstedt, T.,
Jones, M., and D. Waite, "OAuth 2.0 Demonstrating Proof-
of-Possession at the Application Layer (DPoP)", Work in
Progress, Internet-Draft, draft-ietf-oauth-dpop-03, 7
April 2021, <https://www.ietf.org/archive/id/draft-ietf-
oauth-dpop-03.txt>.
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[I-D.ietf-oauth-rar]
Lodderstedt, T., Richer, J., and B. Campbell, "OAuth 2.0
Rich Authorization Requests", Work in Progress, Internet-
Draft, draft-ietf-oauth-rar-05, 15 May 2021,
<https://www.ietf.org/archive/id/draft-ietf-oauth-rar-
05.txt>.
[I-D.ietf-oauth-signed-http-request]
Richer, J., Bradley, J., and H. Tschofenig, "A Method for
Signing HTTP Requests for OAuth", Work in Progress,
Internet-Draft, draft-ietf-oauth-signed-http-request-03, 8
August 2016, <https://www.ietf.org/archive/id/draft-ietf-
oauth-signed-http-request-03.txt>.
[I-D.ietf-secevent-subject-identifiers]
Backman, A. and M. Scurtescu, "Subject Identifiers for
Security Event Tokens", Work in Progress, Internet-Draft,
draft-ietf-secevent-subject-identifiers-08, 24 May 2021,
<https://www.ietf.org/archive/id/draft-ietf-secevent-
subject-identifiers-08.txt>.
[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>.
[RFC3230] Mogul, J. and A. Van Hoff, "Instance Digests in HTTP",
RFC 3230, DOI 10.17487/RFC3230, January 2002,
<https://www.rfc-editor.org/info/rfc3230>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, <https://www.rfc-editor.org/info/rfc5646>.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
<https://www.rfc-editor.org/info/rfc6749>.
[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
Framework: Bearer Token Usage", RFC 6750,
DOI 10.17487/RFC6750, October 2012,
<https://www.rfc-editor.org/info/rfc6750>.
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[RFC7234] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "Hypertext Transfer Protocol (HTTP/1.1): Caching",
RFC 7234, DOI 10.17487/RFC7234, June 2014,
<https://www.rfc-editor.org/info/rfc7234>.
[RFC7468] Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
April 2015, <https://www.rfc-editor.org/info/rfc7468>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<https://www.rfc-editor.org/info/rfc7517>.
[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>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8705] Campbell, B., Bradley, J., Sakimura, N., and T.
Lodderstedt, "OAuth 2.0 Mutual-TLS Client Authentication
and Certificate-Bound Access Tokens", RFC 8705,
DOI 10.17487/RFC8705, February 2020,
<https://www.rfc-editor.org/info/rfc8705>.
[RFC8792] Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
"Handling Long Lines in Content of Internet-Drafts and
RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
<https://www.rfc-editor.org/info/rfc8792>.
Appendix A. Document History
* -00
- Initial individual draft.
Author's Address
Justin Richer (editor)
Bespoke Engineering
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Email: ietf@justin.richer.org
URI: https://bspk.io/
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