SIP Core R. Shekh-Yusef, Ed. Internet-Draft Avaya Updates: 3261 (if approved) C. Holmberg Intended status: Standards Track Ericsson Expires: November 29, 2019 V. Pascual webrtchacks May 28, 2019 Third-Party Token-based Authentication and Authorization for Session Initiation Protocol (SIP) draft-ietf-sipcore-sip-token-authnz-00 Abstract This document defines a mechanism for SIP, that is based on the OAuth 2.0 and OpenID Connect Core 1.0 specifications, to enable the delegation of the user authentication and SIP registration authorization to a dedicated third-party entity that is separate from the SIP network elements that provide the SIP service. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on November 29, 2019. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect Shekh-Yusef, et al. Expires November 29, 2019 [Page 1] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. SIP User Agent Types . . . . . . . . . . . . . . . . . . 3 2. Authentication and Authorization flow . . . . . . . . . . . . 4 2.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Initial Registration . . . . . . . . . . . . . . . . . . 5 2.3. Subsequent Requests . . . . . . . . . . . . . . . . . . . 6 3. Authorization Header Syntax . . . . . . . . . . . . . . . . . 6 4. JWT as Authorization Grant . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 8. Normative References . . . . . . . . . . . . . . . . . . . . 7 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction The SIP protocol [RFC3261] uses the framework used by the HTTP protocol for authenticating users, which is a simple challenge- response authentication mechanism that allows a server to challenge a client request and allows a client to provide authentication information in response to that challenge. OAuth 2.0 [RFC6749] defines a token based authorization framework to allow clients to access resources on behalf of their user. The OpenID Connect 1.0 [OPENID] specifications defines a simple identity layer on top of the OAuth 2.0 protocol, which enables clients to verify the identity of the user based on the Shekh-Yusef, et al. Expires November 29, 2019 [Page 2] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 authentication performed by a dedicated authorization server, as well as to obtain basic profile information about the user. This document defines an mechanism for SIP, that is based on the OAuth 2.0 and OpenID Connect Core 1.0 specifications, to enable the delegation of the user authentication and SIP registration authorization to a dedicated third-party entity that is separate from the SIP network elements that provide the SIP service. 1.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 1.2. SIP User Agent Types [RFC6749] defines two types of clients, confidential and public, that apply to the SIP User Agents. o Confidential User Agent: is a SIP UA that is capable of maintaining the confidentiality of the user credentials and any tokens obtained using these user credentials. o Public User Agent: is a SIP UA that is incapable of maintainings the confidentiality of the user credentials and any obtained tokens. Shekh-Yusef, et al. Expires November 29, 2019 [Page 3] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 2. Authentication and Authorization flow This flow is used by a Confidential UA with rich UI to authenticate to an authorization server and to directly obtain tokens to be able to register and get service from the SIP network. 2.1. Overview The following figure provides a high level view of flow of messages: UA Proxy AS --------------------------------------------------------------------- | | | [00] The UA prompts the user to provides his credentials | | | | | [01] HTTP POST /token | | |-------------------------------------------------------------->| | | | | [02] 200 OK {access_token, refresh_token, [id_token]} | |<--------------------------------------------------------------| | | | | | | | [03] REGISTER with access_token | |------------------------------>| | | | | | | [04] HTTP POST /introspect | | | {access_token} | | |------------------------------>| | | | | | [05] 200 OK {metadata} | | |<------------------------------| | | | | [06] 200 OK | | |<------------------------------| | | | | Shekh-Yusef, et al. Expires November 29, 2019 [Page 4] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 In step [00], the UA collects the user's credentials with the AS. In steps [01] and [02], the UA first contacts the Authorization Server to authenticate the user and obtain tokens to be used to get access to the SIP network. The tokens returned to the UA depend on the type of server: with an OAuth Authorization Server, the tokens provided are the access token and refresh token. With an OpenID Connect server, an additional ID- Token is returned, which contains the SIP URI of the user. The method used to authenticate the user and obtain these tokens is out of scope for this document. In step [03], the UA starts the registration process with the SIP proxy by sending a REGISTER request with the access token it obtained previously. The proxy validates the access token, and if the access token provided by the UA is an opaque token, then then proxy MAY perform an introspection, steps [04] and [05], to obtain more information about the token and its scope, as per [RFC7662]. Otherwise, after the proxy validates the token to make sure it was signed by a trusted entity, it inspects its claims and act upon it. When the proxy is satisfied with the token, it then replies with the 200 OK to complete the registration process. 2.2. Initial Registration In step [03], the UA starts the registration process with the SIP proxy by sending a REGISTER request with the access token it obtained previously. If the access token obtained from the AS is an opaque token, then the UA MUST include an Authorization header field with the Bearer scheme in the request to carry the access token, as epcified in section 3. If the access token obtained from the AS is a JSON Web Token (JWT) [RFC7519], then the UA MUST include the token and grant type in the body of the request, as specified in section 4. When the proxy is satisfied with the token, it then replies with the 200 OK to complete the registration process. Shekh-Yusef, et al. Expires November 29, 2019 [Page 5] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 2.3. Subsequent Requests All subsequent requests from the UA MUST include a valid access token. The UA MUST obtain a new access token before the access token expiry period to continue to get service from the system. 3. Authorization Header Syntax This section describes the syntax of the authorization header with the Bearer scheme. Authorization = "Authorization" HCOLON "Bearer" LWS "access_token" EQUAL access_token COMMA "token_type" EQUAL token_type *(COMMA auth-param) access_token = quoted-string token_type = quoted-string 4. JWT as Authorization Grant This section describes the syntax of the body of the request when a JWT is used to authorize the request, as defined in [RFC7523]. grant_type=urn:ietf:params:oauth:grant-type:jwt-bearer&assertion= 5. Security Considerations TODO 6. IANA Considerations TODO 7. Acknowledgments TODO Shekh-Yusef, et al. Expires November 29, 2019 [Page 6] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 8. Normative References [OPENID] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, "OpenID Connect Core 1.0", February 2014. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261, June 2002, . [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012, . [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content", RFC 7231, DOI 10.17487/RFC7231, June 2014, . [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, . [RFC7523] Jones, M., Campbell, B., and C. Mortimore, "JSON Web Token (JWT) Profile for OAuth 2.0 Client Authentication and Authorization Grants", RFC 7523, DOI 10.17487/RFC7523, May 2015, . [RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection", RFC 7662, DOI 10.17487/RFC7662, October 2015, . Authors' Addresses Rifaat Shekh-Yusef (editor) Avaya 425 Legget Drive Ottawa, Ontario Canada Phone: +1-613-595-9106 EMail: rifaat.ietf@gmail.com Shekh-Yusef, et al. Expires November 29, 2019 [Page 7] Internet-Draft 3rd-Party Token-based AuthNZ for SIP May 2019 Christer Holmberg Ericsson Hirsalantie 11 Jorvas 02420 Finland EMail: christer.holmberg@ericsson.com Victor Pascual webrtchacks Spain EMail: victor.pascual.avila@gmail.com Shekh-Yusef, et al. Expires November 29, 2019 [Page 8]