draft-ietf-sipcore-sip-token-authnz-06.txt   draft-ietf-sipcore-sip-token-authnz-07.txt 
SIP Core R. Shekh-Yusef SIP Core R. Shekh-Yusef
Internet-Draft Avaya Internet-Draft Avaya
Updates: 3261 (if approved) C. Holmberg Updates: 3261 (if approved) C. Holmberg
Intended status: Standards Track Ericsson Intended status: Standards Track Ericsson
Expires: May 23, 2020 V. Pascual Expires: July 18, 2020 V. Pascual
webrtchacks webrtchacks
November 20, 2019 January 15, 2020
Third-Party Token-based Authentication and Authorization for Session Third-Party Token-based Authentication and Authorization for Session
Initiation Protocol (SIP) Initiation Protocol (SIP)
draft-ietf-sipcore-sip-token-authnz-06 draft-ietf-sipcore-sip-token-authnz-07
Abstract Abstract
This document updates RFC 3261 and defines a mechanism for SIP, that This document defines a SIP mechanism that relies on the OAuth 2.0
is based on the OAuth 2.0 and OpenID Connect Core 1.0 specifications, and OpenID Connect Core 1.0 to enable delegation of the user
to enable the delegation of the user authentication and SIP authentication and SIP registration authorization to a third-party.
registration authorization to a dedicated third-party entity that is The document updates RFC 3261.
separate from the SIP network elements that provide the SIP service.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on May 23, 2020. This Internet-Draft will expire on July 18, 2020.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. SIP User Agent Types . . . . . . . . . . . . . . . . . . 3 1.2. SIP User Agent Types . . . . . . . . . . . . . . . . . . 3
2. SIP Procedures . . . . . . . . . . . . . . . . . . . . . . . 4 2. SIP Procedures . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. UAC Behavior . . . . . . . . . . . . . . . . . . . . . . 4 2.1. UAC Behavior . . . . . . . . . . . . . . . . . . . . . . 4
2.1.1. Obtaining Tokens . . . . . . . . . . . . . . . . . . 4 2.1.1. Obtaining Tokens . . . . . . . . . . . . . . . . . . 4
2.1.2. Access Token Claims . . . . . . . . . . . . . . . . . 5 2.1.2. Protecting the Access Token . . . . . . . . . . . . . 5
2.1.3. Protecting the Access Token . . . . . . . . . . . . . 5 2.1.3. REGISTER Request . . . . . . . . . . . . . . . . . . 5
2.1.4. REGISTER Request . . . . . . . . . . . . . . . . . . 5 2.1.4. Non-REGISTER Request . . . . . . . . . . . . . . . . 6
2.1.5. Non-REGISTER Request . . . . . . . . . . . . . . . . 6
2.2. UAS and Registrar Behavior . . . . . . . . . . . . . . . 6 2.2. UAS and Registrar Behavior . . . . . . . . . . . . . . . 6
2.3. Proxy Behavior . . . . . . . . . . . . . . . . . . . . . 7 2.3. Proxy Behavior . . . . . . . . . . . . . . . . . . . . . 6
3. WWW-Authenticate Response Header Field . . . . . . . . . . . 7 3. Access Token Claims . . . . . . . . . . . . . . . . . . . . . 7
4. 'sip.oauth2' Media Feature Tag . . . . . . . . . . . . . . . 8 4. WWW-Authenticate Response Header Field . . . . . . . . . . . 7
5. Example Flows . . . . . . . . . . . . . . . . . . . . . . . . 9 5. Example Flows . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Registration . . . . . . . . . . . . . . . . . . . . . . 9 5.1. Registration . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Registration with Pre-Configured AS . . . . . . . . . . . 10 5.2. Registration with Pre-Configured AS . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. SIP Media Feaure Tag . . . . . . . . . . . . . . . . . . 12
7.1.1. sip.oauth2 . . . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12
9. Normative References . . . . . . . . . . . . . . . . . . . . 13 9. Normative References . . . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
The SIP protocol [RFC3261] uses the framework used by the HTTP The Session Initiation Protocol (SIP) [RFC3261] uses the framework
protocol [RFC7230] for authenticating users, which is a simple used by HTTP [RFC7230] for authenticating users, which is a simple
challenge- response authentication mechanism that allows a server to challenge-response authentication mechanism that allows a server to
challenge a client request and allows a client to provide challenge a client request and allows a client to provide
authentication information in response to that challenge. authentication information in response to that challenge.
OAuth 2.0 [RFC6749] defines a token based authorization framework to OAuth 2.0 [RFC6749] defines a token based authorization framework to
allow clients to access resources on behalf of their user. allow clients to access resources on behalf of their user.
The OpenID Connect 1.0 [OPENID] specifications defines a simple The OpenID Connect 1.0 [OPENID] specifications defines a simple
identity layer on top of the OAuth 2.0 protocol, which enables identity layer on top of the OAuth 2.0 protocol, which enables
clients to verify the identity of the user based on the clients to verify the identity of the user based on the
authentication performed by a dedicated authorization server, as well authentication performed by a dedicated authorization server, as well
as to obtain basic profile information about the user. as to obtain basic profile information about the user.
This document updates [RFC3261], by defining the UAC procedures if it This document updates [RFC3261], by defining the UAC procedures if it
receives a 401/407 response with multiple WWW-Authenticate/Proxy- receives a 401/407 response with multiple WWW-Authenticate/Proxy-
Authenticate header fields, providing challenges using different Authenticate header fields, providing challenges using different
authentication schemes for the same realm. authentication schemes for the same realm.
This document defines an mechanism for SIP, that is based on the This document defines an mechanism for SIP, that relies on the OAuth
OAuth 2.0 and OpenID Connect Core 1.0 specifications, to enable the 2.0 and OpenID Connect Core 1.0 specifications, to enable the
delegation of the user authentication and SIP registration delegation of the user authentication and SIP registration
authorization to a dedicated third-party entity that is separate from authorization to a dedicated third-party entity that is separate from
the SIP network elements that provide the SIP service. the SIP network elements that provide the SIP service.
1.1. Terminology 1.1. 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", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1.2. SIP User Agent Types 1.2. SIP User Agent Types
[RFC6749] defines two types of clients, confidential and public, that [RFC6749] defines two types of clients, confidential and public, that
apply to the SIP User Agents. apply to the SIP User Agents.
o Confidential User Agent: is a SIP UA that is capable of o Confidential User Agent: is a SIP UA that is capable of
maintaining the confidentiality of the user credentials and any maintaining the confidentiality of the user credentials and any
tokens obtained using these user credentials. tokens obtained using these user credentials.
o Public User Agent: is a SIP UA that is incapable of maintainings o Public User Agent: is a SIP UA that is incapable of maintaining
the confidentiality of the user credentials and any obtained the confidentiality of the user credentials and any obtained
tokens. tokens.
The mechanism defined in this document MUST only be used with
Confidential User Agents, as the UA is expected to obtain and
maintain tokens to be able to access the SIP network.
2. SIP Procedures 2. SIP Procedures
Section 22 of [RFC3261] defines the SIP procedures for the Digest Section 22 of [RFC3261] defines the SIP procedures for the Digest
authentication mechanism procedures. The same procedures apply to authentication mechanism procedures. The same procedures apply to
the Bearer authentication mechanism, with the changes described in the Bearer authentication mechanism, with the changes described in
this section. this section.
2.1. UAC Behavior 2.1. UAC Behavior
2.1.1. Obtaining Tokens 2.1.1. Obtaining Tokens
When a UAC sends a request without credentials (or with credentials When a UAC sends a request without credentials (or with credentials
that are no longer valid), and receives a 401 (Unauthorized) or a 407 that are no longer valid), and receives a 401 (Unauthorized) or a 407
(Proxy Authentication Required) response that contains a WWW- (Proxy Authentication Required) response that contains a WWW-
Authenticate header field (in case of a 401 response) or a Proxy- Authenticate header field (in case of a 401 response) or a Proxy-
Authenticate header field (in case of a 407 response) that indicates Authenticate header field (in case of a 407 response) that indicates
"Bearer" scheme authentication and contains an address to an "Bearer" scheme authentication and contains an address to an
Authorization Server, the UAC contacts the Authorization Server in Authorization Server, the UAC contacts the Authorization Server in
order to obtain tokens, and includes the requested scopes based on a order to obtain tokens, and includes the requested scopes, based on a
local configuration. The tokens returned to the UA depend on the local configuration.
type of server: with an OAuth AS, the tokens provided are the access
token and refresh token. The access token will be sent to the SIP
servers to authorize UAC's access to the service. The refresh token
will only be used with the AS to get new access token and refresh
token, before the expiry of the current access token. With an OpenID
Connect server, an additional ID-Token is returned, which contains
the SIP URI and other user specific details, and will be consumed by
the UAC.
The method used to authenticate the user and obtain these tokens is The tokens returned to the UA depend on the type of AS: with an OAuth
out of scope for this document, with one potential method is the AS, the tokens provided are the access token and refresh token. The
Native App mechanism defined in [RFC8252]. The advantages of using access token will be sent to the SIP servers to authorize UAC's
the mechanism defined in [RFC8252] is that the user will be directed access to the service. The refresh token will only be used with the
to use a browser to interact with the authorization server. This AS to get new access token and refresh token, before the expiry of
allows the authorization server to prompt the user for multi-factor the current access token. With an OpenID Connect server, an
authentication, redirect the user to third-party identity providers, additional ID-Token is returned, which contains the SIP URI and other
and the use of single-sign-on sessions. user specific details, and will be consumed by the UAC.
The detailed OAuth2 procedure to authenticate the user and obtain
these tokens is out of scope of this document. [RFC8252] defines
procedures for native applications. When using the mechanism defined
in [RFC8252] the user will be directed to use a browser for the
interaction with the authorization server, allowing the authorization
server to prompt the user for multi-factor authentication, redirect
the user to third-party identity providers, and the use of single-
sign-on sessions.
If the UAC receives a 401/407 response with multiple WWW- If the UAC receives a 401/407 response with multiple WWW-
Authenticate/Proxy-Authenticate header fields, providing challenges Authenticate/Proxy-Authenticate header fields, providing challenges
using different authentication schemes for the same realm, the UAC using different authentication schemes for the same realm, the UAC
provides credentials for one or more of the schemes that it supports, provides credentials for one or more of the schemes that it supports,
based on local policy. based on local policy.
NOTE: The address of the Authorization Server might be known to the NOTE: The address of the Authorization Server might be known to the
UAC e.g., using means of configuration, in which case the UAC can UAC e.g., using means of configuration, in which case the UAC can
contact the Authorization Server in order to obtain the access token contact the Authorization Server in order to obtain the access token
before it sends SIP request without credentials. before it sends SIP request without credentials.
2.1.2. Access Token Claims 2.1.2. Protecting the Access Token
The type of services that an access token grants access to can be
determined using different methods. Which methods are used is based
on local policy. If an access token is encoded as a JWT, it might
contain a list of claims [RFC7519], some registered and some are
application specific claims. The REGISTRAR can grant access to
services either based on such claims, using some other mechanism, or
a combination of claims and some other mechanism. If an access token
is a reference token, the REGISTRAR will grant access based on some
other mechanism. Examples of such other mechanisms are introspection
[RFC7662], user profile lookups, etc.
2.1.3. Protecting the Access Token
[RFC6749] mandates that Access Tokens are protected with TLS when in [RFC6749] mandates that Access Tokens are protected with TLS when in
transit. However, TLS only guarantees hop-to-hop protection when transit. However, TLS only guarantees hop-to-hop protection when
used to protect SIP signaling. Therefore the Access Token MUST be used to protect SIP signaling. Therefore the Access Token MUST be
protected in a way so that only authorized SIP servers will have protected in a way so that only authorized SIP servers will have
access to it. Endpoints that support this specifications MUST access to it. Endpoints that support this specification MUST support
support encrypted JSON Web Tokens (JWT) [RFC7519] for encoding and encrypted JSON Web Tokens (JWT) [RFC7519] for encoding and protecting
protecting Access Token when included in SIP requests, unless some Access Token when included in SIP requests, unless some other
other mechanism is used to guarantee that only authorized SIP mechanism is used to guarantee that only authorized SIP endpoints
endpoints have access to the Access Token. have access to the Access Token.
2.1.4. REGISTER Request 2.1.3. REGISTER Request
The procedures in this section assumes that the UAC has obtained a The procedures in this section assumes that the UAC has obtained a
token as specified in section Section 2.1.1 token as specified in section Section 2.1.1
When a UAC sends a REGISTER request in order to create a binding, it When the UAC sends a REGISTER request after it received a challenge
MUST include an Authorization headerf field with a Bearer scheme, containing the Bearer scheme, then to resolve that particular
carrying the access token, in the request, as specified in [RFC6750]. challenge it needs to send a request with an Authorization header
field containing the response to that challenge, including the Bearer
scheme carrying a valid access token in the request, as specified in
[RFC6750].
Note that if there were multiple challenges with different schemes
then it maybe able to successfully retry the request using non-Bearer
credentials.
Based on local policy, the UAC MAY include an access token that has Based on local policy, the UAC MAY include an access token that has
been used for another binding associated with the same AOR in the been used for another binding associated with the same AOR in the
request. request.
When the UAC sends a binding refresh REGISTER request, it SHOULD
include an Authorization header field with either the access token
previously used for the binding, or a new access token (obtained
using the refresh token) if the previous one has expired.
If the access token included in a REGISTER request is not accepted, If the access token included in a REGISTER request is not accepted,
and the UAC receives a 401 response or a 407 response, the UAC and the UAC receives a 401 response or a 407 response, the UAC
follows the procedures in Section 2.1.1. follows the procedures in Section 2.1.1.
2.1.5. Non-REGISTER Request 2.1.4. Non-REGISTER Request
The procedures in this section assumes that the UAC has obtained a The procedures in this section assumes that the UAC has obtained a
token as specified in section Section 2.1.1 token as specified in section Section 2.1.1
When a UAC sends a request in order to initiate a SIP dialog, or When a UAC sends a request, after it received a challenge containing
sends a stand-alone request, the UAC MUST include an Authorization the Bearer scheme, then the UAC MUST include an Authorization header
header field with a Bearer scheme, carrying the access token, in the field with a Bearer scheme, carrying a valid access token in the
request, as specified in [RFC6750]. Based on local policy, the UAC request, as specified in [RFC6750]. Based on local policy, the UAC
MAY include an access token that has been used for another dialog, or MAY include an access token that has been used for another dialog, or
for another stand-alone request, if the target of the new request is for another stand-alone request, if the target of the new request is
the same. the same.
When the UAC sends a mid-dialog request, the UAC SHOULD include an
Authorization header field with either the access token previously
used within the dialog, or with a new access token if the previous
one has expired or the UAC refreshed the access token before its
expiry time.
If the access token included in a request is not accepted, and the If the access token included in a request is not accepted, and the
UAC receives a 401 response or a 407 response, the UAC follows the UAC receives a 401 response or a 407 response, the UAC follows the
procedures in Section 2.1.1. procedures in Section 2.1.1.
2.2. UAS and Registrar Behavior 2.2. UAS and Registrar Behavior
When a UAS or a Registrar receives a SIP request that does not When a UAS or Registrar receives a request that fails to contain
contain an Authorization header field with a valid access token, and authorization credentials acceptable to it, it SHOULD challenge the
the UAS/Proxy decides to challenge the originator of the request, the request by sending a 401 (Unauthorized) response. To indicate that
proxy MUST challenge the request and send a 401 (Unauthorized) it is willing to accept an OAuth2 token as a credential the UAS/
response. The UAS/Proxy MUST include a Proxy-Authentication header Registrar MUST include a Proxy-Authentication header field in the
field in the response, indicate "Bearer" scheme and include an response, indicate "Bearer" scheme and include an address of an
address to an Authorization Server from there the originator can Authorization Server from which the originator can obtain an access
obtain an access token. token.
When a UAS/Registrar receives a SIP request that contains an When a UAS/Registrar receives a SIP request that contains an
Authorization header field with an access token, the UAS/Registrar Authorization header field with an access token, the UAS/Registrar
MUST validate the access token, using the procedures associated with MUST validate the access token, using the procedures associated with
the type of access token used. If the validation is successful the the type of access token used, e.g. [RFC7519]. If the validation is
UAS/Registrar can continue to process the request using normal SIP successful the UAS/Registrar can continue to process the request
procedures. If the validation fails, the UAS/Registrar MUST reject using normal SIP procedures. If the validation fails, the UAS/
the request. Registrar MUST reject the request.
2.3. Proxy Behavior 2.3. Proxy Behavior
When a proxy receives a SIP request that does not contain a Proxy- When a proxy receives a request that fails to contain authorization
Authorization header field with a valid access token, and the proxy credentials acceptable to it, it SHOULD challenge the request by
decides to challenge the originator of the request, the proxy MUST sending a 407 (Proxy Authentication Required) response. To indicate
challenge the request and send a 407 (Proxy Authentication Required) that it is willing to accept an OAuth2 token as a credential the
response. The proxy MUST include a Proxy-Authentication header field proxy MUST include a Proxy-Authentication header field in the
in the response, indicate "Bearer" scheme and include an address to response, indicating "Bearer" scheme and including an address to an
an Authorization Server from there the originator can obtain an Authorization Server from which the originator can obtain an access
access token. token.
When a proxy receives a SIP request that contains an Proxy- When a proxy wishes to authenticate a received request, it MUST
Authorization header field with an access token, and the proxy has search the request for Proxy-Authorization header fields with 'realm'
previously challenged the originator of the request, the proxy MUST parameters that match its realm. It then MUST successfully validate
validate the access token, using the procedures associated with the the credentials from at least one Proxy-Authorization header field
type of access token used. If the validation is successful the proxy for its realm. When the scheme is Bearer the proxy MUST validate the
can continue to process the request using normal SIP procedure. If access token, using the procedures associated with the type of access
the validation fails, the UAS/Registrar MUST reject the request. token used, e.g. [RFC7519].
3. WWW-Authenticate Response Header Field 3. Access Token Claims
The type of services that an access token grants access to can be
determined using different methods. Which methods are used and the
granted access provided by the token is based on local policy agreed
between the AS and the registrar.
If an access token is encoded as a JWT, it might contain a list of
claims [RFC7519], some registered and some are application specific
claims. The REGISTRAR can grant access to services either based on
such claims, using some other mechanism, or a combination of claims
and some other mechanism. If an access token is a reference token,
the REGISTRAR will grant access based on some other mechanism.
Examples of such other mechanisms are introspection [RFC7662], user
profile lookups, etc.
4. WWW-Authenticate Response Header Field
This section describes the syntax of the WWW-Authenticate Response This section describes the syntax of the WWW-Authenticate Response
Header Field when used with the Bearer scheme to challenge the UA for Header Field when used with the Bearer scheme to challenge the UA for
credentials. credentials, by extending the 'challnge' header field defined by
[RFC3261].
challenge =/ ("Bearer" LWS bearer-cln *(COMMA bearer-cln)) challenge =/ ("Bearer" LWS bearer-cln *(COMMA bearer-cln))
bearer-cln = realm / scope / authz-server / error / bearer-cln = realm / scope / authz-server / error /
auth-param auth-param
authz-server = "authz_server" EQUAL authz-server-value authz-server = "authz_server" EQUAL authz-server-value
authz-server-value = https-URI authz-server-value = https-URI
realm = <defined in RFC3261>
auth-param = <defined in RFC3261>
scope = <defined in RFC6749>
error = <defined in RFC6749>
https-URI = <defined in RFC7230>
The authz-server parameters contains the HTTPS URI, as defined in The authz-server parameters contains the HTTPS URI, as defined in
[RFC7230], of the authorization server. [RFC7230], of the authorization server. The UA can discover metadata
about the AS using a mechanism like the one defined in [RFC8414].
The realm and auth-param parameters are defined in [RFC3261]. The realm and auth-param parameters are defined in [RFC3261].
As per [RFC3261], the realm string alone defines the protection As per [RFC3261], the realm string alone defines the protection
domain. [RFC3261] states that the realm string must be globally domain. [RFC3261] states that the realm string must be globally
unique and recommends that the realm string contains a hostname or unique and recommends that the realm string contains a hostname or
domain name. It also states that the realm string should be human- domain name. It also states that the realm string should be human-
readable identifier that can be rendered to the user. readable identifier that can be rendered to the user.
The scope and error parameters are defined in [RFC6749]. The scope and error parameters are defined in [RFC6749].
The scope parameter could be used by the registrar/proxy to indicate The scope parameter could be used by the registrar/proxy to indicate
to the UAC the minimum scope that must be associated with the access to the UAC the minimum scope that must be associated with the access
token to be able to get service. As defined in [RFC6749], the value token to be able to get service. As defined in [RFC6749], the value
of the scope parameter is expressed as a list of space-delimited, of the scope parameter is expressed as a list of space-delimited,
case-sensitive strings. The strings are defined by the authorization case-sensitive strings. The strings are defined by the authorization
server. The values of the scope parameter is out of scope for this server. The values of the scope parameter is out of scope of this
document. document. The UAC will use the scope provided by the registrar to
contact the AS and obtain a proper token with the requested scope.
The error parameter could be used by the registrar/proxy to indicate The error parameter could be used by the registrar/proxy to indicate
to the UAC the reason for the error, with possible values of to the UAC the reason for the error, with possible values of
"invalid_token" or "invalid_scope". "invalid_token" or "invalid_scope".
4. 'sip.oauth2' Media Feature Tag
The sip.oauth2 media feature tag, when inserted in the Contact header
field of a SIP REGISTER request, conveys that the SIP UA associated
with the tag supports a token based authentication mechanism, where
the user authentication and SIP registration authorization is
performed by a third party. The media feature tag has no values.
token-mt = "+sip.oauth2"
5. Example Flows 5. Example Flows
5.1. Registration 5.1. Registration
The figure belows show an example of a SIP registration, where the UA The figure below shows an example of a SIP registration, where the UA
is informed about the Authorization Server (AS) from where to obtain is informed about the Authorization Server (AS) from where to obtain
an access token by the registratar in a 401 response to the REGISTER an access token by the registratar in a 401 response to the REGISTER
request. request.
UA Registrar AS UA Registrar AS
--------------------------------------------------------------------- ---------------------------------------------------------------------
| | | | | |
| [1] REGISTER | | | [1] REGISTER | |
|------------------------------>| | |------------------------------>| |
| | | | | |
skipping to change at page 9, line 43 skipping to change at page 9, line 34
| |------------------------------>| | |------------------------------>|
| | | | | |
| | [6] 200 OK {metadata} | | | [6] 200 OK {metadata} |
| |<------------------------------| | |<------------------------------|
| | | | | |
| [7] 200 OK | | | [7] 200 OK | |
|<------------------------------| | |<------------------------------| |
| | | | | |
In step [1], the UA starts the registration process by sending a SIP In step [1], the UA starts the registration process by sending a SIP
REGISTER request to the registrar without any credentials. The REGISTER request to the registrar without any credentials.
REGISTER request includes an indication that the UA supports token-
based autentication, using a sip.oauth2 media feature tag.
In step [2], the registrar challenges the UA, by sending a SIP 401 In step [2], the registrar challenges the UA, by sending a SIP 401
(Unauthorized) response to the REGISTER request. In the response the (Unauthorized) response to the REGISTER request. In the response the
registrar includes information about the AS to contact in order to registrar includes information about the AS to contact in order to
obtain a token. obtain a token.
In step [3], the UA interacts with the AS, potentially using the In step [3], the UA interacts with the AS, potentially using the
OAuth Native App mechanism defined in [RFC8252], authenticates the OAuth Native App mechanism defined in [RFC8252], authenticates the
user and obtains the tokens needed to access the SIP service. user and obtains the tokens needed to access the SIP service.
skipping to change at page 10, line 26 skipping to change at page 10, line 14
access token and its scope, as per [RFC7662]. Otherwise, after the access token and its scope, as per [RFC7662]. Otherwise, after the
registrar validates the token to make sure it was signed by a trusted registrar validates the token to make sure it was signed by a trusted
entity, it inspects its claims and act upon it. entity, it inspects its claims and act upon it.
In step [7], once the registrar has succesfully verified and accepted In step [7], once the registrar has succesfully verified and accepted
the access token, it sends a 200 (OK) response to the REGISTER the access token, it sends a 200 (OK) response to the REGISTER
request. request.
5.2. Registration with Pre-Configured AS 5.2. Registration with Pre-Configured AS
The figure belows show an example of a SIP registration, where the UA The figure below shows an example of a SIP registration, where the UA
has pre-configured information about the Authorization Server (AS) has pre-configured information about the Authorization Server (AS)
from where to obtain the access token. from where to obtain the access token.
UA Registrar AS UA Registrar AS
--------------------------------------------------------------------- ---------------------------------------------------------------------
| | | | | |
| [1] The UA interacts with the AS and obtains tokens, using | | [1] The UA interacts with the AS and obtains tokens, using |
| some out of scope mechanism. | | some out of scope mechanism. |
|<=============================================================>| |<=============================================================>|
| | | | | |
skipping to change at page 12, line 7 skipping to change at page 12, line 7
protect SIP signaling. Therefore the Access Token MUST be protected protect SIP signaling. Therefore the Access Token MUST be protected
in a way so that only authorized SIP endpoints will have access to in a way so that only authorized SIP endpoints will have access to
it. Endpoints that support this specifications MUST support it. Endpoints that support this specifications MUST support
encrypted JSON Web Tokens (JWT) [RFC7519] for encoding and protecting encrypted JSON Web Tokens (JWT) [RFC7519] for encoding and protecting
Access Token when included in SIP requests, unless some other Access Token when included in SIP requests, unless some other
mechanism is used to guarantee that only authorized SIP endpoints mechanism is used to guarantee that only authorized SIP endpoints
have access to the Access Token. have access to the Access Token.
7. IANA Considerations 7. IANA Considerations
7.1. SIP Media Feaure Tag
7.1.1. sip.oauth2
This section defines a new media feature tag that extends the "SIP
Media Feature Tag Registration Tree" subregistry [RFC3840] under the
"Media Feature Tags" registry (https://www.iana.org/assignments/
media-feature-tags).
Media feature tag name: sip.oauth2
Summary of the media feature indicated by this feature tag: This
media feature tag, when inserted in the Contact header field
of a SIP REGISTER request, conveys that the SIP UA associated
with the tag supports a token based authentication mechanism,
where the user authentication and SIP registration
authorization is performed by a third party.
Values appropriate for use with this feature tag: none
Related standards or documents: RFC XXXX
Security considerations: This media feature tag does not introduce
new security considerations, as it simply indicates support for
a basic SIP feature. However, if an attacker manages to remove
the media feature tag from a SIP REGISTER request, the SIP UA
that inserted it might not be able to authenticate itself with
the SIP registrar to which the SIP request is addressed, as the
SIP registrar might not be aware that the SIP UA supports the
feature associated with the media feature tag.
Contact: IESG (iesg@ietf.org)
8. Acknowledgments 8. Acknowledgments
The authors would like to specially thank Paul Kyzivat for his
multiple detailed reviews and suggested text that significanly
improved the quality of the document.
The authors would also like to thank the following for their review The authors would also like to thank the following for their review
and feedback on this document: and feedback on this document:
Paul Kyzivat, Olle Johansson, Roman Shpount, and Dale Worley. Olle Johansson, Roman Shpount, Dale Worley, and Jorgen Axell.
The authors would also like to thank the following for their review The authors would also like to thank the following for their review
and feedback of the original document that was replaced with this and feedback of the original document that was replaced with this
document: document:
Andrew Allen, Martin Dolly, Keith Drage, Paul Kyzivat, Jon Peterson, Andrew Allen, Martin Dolly, Keith Drage, Paul Kyzivat, Jon Peterson,
Michael Procter, Roy Radhika, Matt Ryan, Ivo Sedlacek, Roman Shpount, Michael Procter, Roy Radhika, Matt Ryan, Ivo Sedlacek, Roman Shpount,
Robert Sparks, Asveren Tolga, and Dale Worley. Robert Sparks, Asveren Tolga, and Dale Worley.
9. Normative References 9. Normative References
[OPENID] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and [OPENID] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0", February 2014. C. Mortimore, "OpenID Connect Core 1.0", February 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, <https://www.rfc- DOI 10.17487/RFC2119, March 1997,
editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
A., Peterson, J., Sparks, R., Handley, M., and E. A., Peterson, J., Sparks, R., Handley, M., and E.
Schooler, "SIP: Session Initiation Protocol", RFC 3261, Schooler, "SIP: Session Initiation Protocol", RFC 3261,
DOI 10.17487/RFC3261, June 2002, <https://www.rfc- DOI 10.17487/RFC3261, June 2002,
editor.org/info/rfc3261>. <https://www.rfc-editor.org/info/rfc3261>.
[RFC3840] Rosenberg, J., Schulzrinne, H., and P. Kyzivat, [RFC3840] Rosenberg, J., Schulzrinne, H., and P. Kyzivat,
"Indicating User Agent Capabilities in the Session "Indicating User Agent Capabilities in the Session
Initiation Protocol (SIP)", RFC 3840, Initiation Protocol (SIP)", RFC 3840,
DOI 10.17487/RFC3840, August 2004, <https://www.rfc- DOI 10.17487/RFC3840, August 2004,
editor.org/info/rfc3840>. <https://www.rfc-editor.org/info/rfc3840>.
[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>.
[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization [RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
Framework: Bearer Token Usage", RFC 6750, Framework: Bearer Token Usage", RFC 6750,
DOI 10.17487/RFC6750, October 2012, <https://www.rfc- DOI 10.17487/RFC6750, October 2012,
editor.org/info/rfc6750>. <https://www.rfc-editor.org/info/rfc6750>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing", Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014, RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>. <https://www.rfc-editor.org/info/rfc7230>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>. <https://www.rfc-editor.org/info/rfc7519>.
[RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection", [RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection",
RFC 7662, DOI 10.17487/RFC7662, October 2015, RFC 7662, DOI 10.17487/RFC7662, October 2015,
<https://www.rfc-editor.org/info/rfc7662>. <https://www.rfc-editor.org/info/rfc7662>.
[RFC8252] Denniss, W. and J. Bradley, "OAuth 2.0 for Native Apps", [RFC8252] Denniss, W. and J. Bradley, "OAuth 2.0 for Native Apps",
BCP 212, RFC 8252, DOI 10.17487/RFC8252, October 2017, BCP 212, RFC 8252, DOI 10.17487/RFC8252, October 2017,
<https://www.rfc-editor.org/info/rfc8252>. <https://www.rfc-editor.org/info/rfc8252>.
[RFC8414] Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0
Authorization Server Metadata", RFC 8414,
DOI 10.17487/RFC8414, June 2018,
<https://www.rfc-editor.org/info/rfc8414>.
Authors' Addresses Authors' Addresses
Rifaat Shekh-Yusef Rifaat Shekh-Yusef
Avaya Avaya
425 Legget Drive 425 Legget Drive
Ottawa, Ontario Ottawa, Ontario
Canada Canada
Phone: +1-613-595-9106 Phone: +1-613-595-9106
EMail: rifaat.ietf@gmail.com EMail: rifaat.ietf@gmail.com
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