draft-ietf-oauth-saml2-bearer-17.txt   draft-ietf-oauth-saml2-bearer-18.txt 
OAuth Working Group B. Campbell OAuth Working Group B. Campbell
Internet-Draft Ping Identity Internet-Draft Ping Identity
Intended status: Standards Track C. Mortimore Intended status: Standards Track C. Mortimore
Expires: January 15, 2014 Salesforce Expires: June 12, 2014 Salesforce
M. Jones M. Jones
Microsoft Microsoft
July 14, 2013 December 9, 2013
SAML 2.0 Profile for OAuth 2.0 Client Authentication and Authorization SAML 2.0 Profile for OAuth 2.0 Client Authentication and Authorization
Grants Grants
draft-ietf-oauth-saml2-bearer-17 draft-ietf-oauth-saml2-bearer-18
Abstract Abstract
This specification defines the use of a SAML 2.0 Bearer Assertion as This specification defines the use of a SAML 2.0 Bearer Assertion as
a means for requesting an OAuth 2.0 access token as well as for use a means for requesting an OAuth 2.0 access token as well as for use
as a means of client authentication. as a means of client authentication.
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
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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This Internet-Draft will expire on January 15, 2014. This Internet-Draft will expire on June 12, 2014.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 4 1.1. Notational Conventions . . . . . . . . . . . . . . . . . 4
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. HTTP Parameter Bindings for Transporting Assertions . . . . . 4 2. HTTP Parameter Bindings for Transporting Assertions . . . . . 4
2.1. Using SAML Assertions as Authorization Grants . . . . . . 5 2.1. Using SAML Assertions as Authorization Grants . . . . . . 4
2.2. Using SAML Assertions for Client Authentication . . . . . 5 2.2. Using SAML Assertions for Client Authentication . . . . . 5
3. Assertion Format and Processing Requirements . . . . . . . . . 6 3. Assertion Format and Processing Requirements . . . . . . . . 6
3.1. Authorization Grant Processing . . . . . . . . . . . . . . 8 3.1. Authorization Grant Processing . . . . . . . . . . . . . 8
3.2. Client Authentication Processing . . . . . . . . . . . . . 9 3.2. Client Authentication Processing . . . . . . . . . . . . 9
4. Authorization Grant Example . . . . . . . . . . . . . . . . . 9 4. Authorization Grant Example . . . . . . . . . . . . . . . . . 9
5. Interoperability Considerations . . . . . . . . . . . . . . . 11 5. Interoperability Considerations . . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7.1. Sub-Namespace Registration of 7.1. Sub-Namespace Registration of urn:ietf:params:oauth
urn:ietf:params:oauth:grant-type:saml2-bearer . . . . . . 11 :grant-type:saml2-bearer . . . . . . . . . . . . . . . . 11
7.2. Sub-Namespace Registration of 7.2. Sub-Namespace Registration of urn:ietf:params:oauth
urn:ietf:params:oauth:client-assertion-type:saml2-bearer . 12 :client-assertion-type:saml2-bearer . . . . . . . . . . . 12
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
8.1. Normative References . . . . . . . . . . . . . . . . . . . 12 8.1. Normative References . . . . . . . . . . . . . . . . . . 12
8.2. Informative References . . . . . . . . . . . . . . . . . . 13 8.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 13 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 14
Appendix B. Document History . . . . . . . . . . . . . . . . . . 14 Appendix B. Document History . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 20
1. Introduction 1. Introduction
The Security Assertion Markup Language (SAML) 2.0 The Security Assertion Markup Language (SAML) 2.0
[OASIS.saml-core-2.0-os] is an XML-based framework that allows [OASIS.saml-core-2.0-os] is an XML-based framework that allows
identity and security information to be shared across security identity and security information to be shared across security
domains. The SAML specification, while primarily targeted at domains. The SAML specification, while primarily targeted at
providing cross domain Web browser single sign-on, was also designed providing cross domain Web browser single sign-on, was also designed
to be modular and extensible to facilitate use in other contexts. to be modular and extensible to facilitate use in other contexts.
skipping to change at page 5, line 20 skipping to change at page 5, line 9
Grants [I-D.ietf-oauth-assertions] specification with the following Grants [I-D.ietf-oauth-assertions] specification with the following
specific parameter values and encodings. specific parameter values and encodings.
The value of the "grant_type" parameter MUST be The value of the "grant_type" parameter MUST be
"urn:ietf:params:oauth:grant-type:saml2-bearer". "urn:ietf:params:oauth:grant-type:saml2-bearer".
The value of the "assertion" parameter MUST contain a single SAML 2.0 The value of the "assertion" parameter MUST contain a single SAML 2.0
Assertion. The SAML Assertion XML data MUST be encoded using Assertion. The SAML Assertion XML data MUST be encoded using
base64url, where the encoding adheres to the definition in Section 5 base64url, where the encoding adheres to the definition in Section 5
of RFC 4648 [RFC4648] and where the padding bits are set to zero. To of RFC 4648 [RFC4648] and where the padding bits are set to zero. To
avoid the need for subsequent encoding steps (by "application/ avoid the need for subsequent encoding steps (by "application/x-www-
x-www-form-urlencoded" [W3C.REC-html401-19991224], for example), the form-urlencoded" [W3C.REC-html401-19991224], for example), the
base64url encoded data SHOULD NOT be line wrapped and pad characters base64url encoded data SHOULD NOT be line wrapped and pad characters
("=") SHOULD NOT be included. ("=") SHOULD NOT be included.
The "scope" parameter may be used, as defined in the Assertion The "scope" parameter may be used, as defined in the Assertion
Framework for OAuth 2.0 Client Authentication and Authorization Framework for OAuth 2.0 Client Authentication and Authorization
Grants [I-D.ietf-oauth-assertions] specification, to indicate the Grants [I-D.ietf-oauth-assertions] specification, to indicate the
requested scope. requested scope.
Authentication of the client is optional, as described in Section Authentication of the client is optional, as described in
3.2.1 of OAuth 2.0 [RFC6749] and consequently, the "client_id" is Section 3.2.1 of OAuth 2.0 [RFC6749] and consequently, the
only needed when a form of client authentication that relies on the "client_id" is only needed when a form of client authentication that
parameter is used. relies on the parameter is used.
The following non-normative example demonstrates an Access Token The following non-normative example demonstrates an Access Token
Request with an assertion as an authorization grant (with extra line Request with an assertion as an authorization grant (with extra line
breaks for display purposes only): breaks for display purposes only):
POST /token.oauth2 HTTP/1.1 POST /token.oauth2 HTTP/1.1
Host: as.example.com Host: as.example.com
Content-Type: application/x-www-form-urlencoded Content-Type: application/x-www-form-urlencoded
grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Asaml2-bearer& grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3Asaml2-bearer&
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3. Assertion Format and Processing Requirements 3. Assertion Format and Processing Requirements
In order to issue an access token response as described in OAuth 2.0 In order to issue an access token response as described in OAuth 2.0
[RFC6749] or to rely on an Assertion for client authentication, the [RFC6749] or to rely on an Assertion for client authentication, the
authorization server MUST validate the Assertion according to the authorization server MUST validate the Assertion according to the
criteria below. Application of additional restrictions and policy criteria below. Application of additional restrictions and policy
are at the discretion of the authorization server. are at the discretion of the authorization server.
1. The Assertion's <Issuer> element MUST contain a unique 1. The Assertion's <Issuer> element MUST contain a unique
identifier for the entity that issued the Assertion. Issuer identifier for the entity that issued the Assertion. In the
values SHOULD be compared using the Simple String Comparison absence of an application profile specifying otherwise,
method defined in Section 6.2.1 of RFC 3986 [RFC3986], unless compliant applications MUST compare Issuer values using the
otherwise specified by the application. Simple String Comparison method defined in Section 6.2.1 of RFC
3986 [RFC3986].
2. The Assertion MUST contain a <Conditions> element with an 2. The Assertion MUST contain a <Conditions> element with an
<AudienceRestriction> element with an <Audience> element that <AudienceRestriction> element with an <Audience> element that
identifies the authorization server as an intended audience. identifies the authorization server as an intended audience.
Section 2.5.1.4 of Assertions and Protocols for the OASIS Section 2.5.1.4 of Assertions and Protocols for the OASIS
Security Assertion Markup Language [OASIS.saml-core-2.0-os] Security Assertion Markup Language [OASIS.saml-core-2.0-os]
defines the <AudienceRestriction> and <Audience> elements and, defines the <AudienceRestriction> and <Audience> elements and,
in addition to the URI references discussed there, the token in addition to the URI references discussed there, the token
endpoint URL of the authorization server MAY be used as a URI endpoint URL of the authorization server MAY be used as a URI
that identifies the authorization server as an intended that identifies the authorization server as an intended
audience. Assertions that do not identify the Authorization audience. Assertions that do not identify the Authorization
Server as an intended audience MUST be rejected. Audience Server as an intended audience MUST be rejected. In the absence
values SHOULD be compared using the Simple String Comparison of an application profile specifying otherwise, compliant
method defined in Section 6.2.1 of RFC 3986 [RFC3986], unless applications MUST compare the audience values using the Simple
otherwise specified by the application. String Comparison method defined in Section 6.2.1 of RFC 3986
[RFC3986].
3. The Assertion MUST contain a <Subject> element. The subject MAY 3. The Assertion MUST contain a <Subject> element identifying the
identify the resource owner for Additional information principal that is the subject of the Assertion. Additional
identifying the subject/principal of the transaction MAY be information identifying the subject/principal MAY be included in
included in an <AttributeStatement>. an <AttributeStatement>.
A. When using an Assertion as an authorization grant, the A. For the authorization grant, the Subject SHOULD identify an
Subject SHOULD identify an authorized accessor for whom the authorized accessor for whom the access token is being
access token is being requested (typically the resource requested (typically the resource owner, or an authorized
owner, or an authorized delegate). delegate).
B. For client authentication, the Subject MUST be the B. For client authentication, the Subject MUST be the
"client_id" of the OAuth client. "client_id" of the OAuth client.
4. The Assertion MUST have an expiry that limits the time window 4. The Assertion MUST have an expiry that limits the time window
during which it can be used. The expiry can be expressed either during which it can be used. The expiry can be expressed either
as the NotOnOrAfter attribute of the <Conditions> element or as as the NotOnOrAfter attribute of the <Conditions> element or as
the NotOnOrAfter attribute of a suitable the NotOnOrAfter attribute of a suitable
<SubjectConfirmationData> element. <SubjectConfirmationData> element.
5. The <Subject> element MUST contain at least one 5. The <Subject> element MUST contain at least one
<SubjectConfirmation> element that allows the authorization <SubjectConfirmation> element that has a Method attribute with a
server to confirm it as a Bearer Assertion. Such a value of "urn:oasis:names:tc:SAML:2.0:cm:bearer". The
<SubjectConfirmation> element MUST have a Method attribute with
a value of "urn:oasis:names:tc:SAML:2.0:cm:bearer". The
<SubjectConfirmation> element MUST contain a <SubjectConfirmation> element MUST contain a
<SubjectConfirmationData> element, unless the Assertion has a <SubjectConfirmationData> element, unless the Assertion has a
suitable NotOnOrAfter attribute on the <Conditions> element, in suitable NotOnOrAfter attribute on the <Conditions> element, in
which case the <SubjectConfirmationData> element MAY be omitted. which case the <SubjectConfirmationData> element MAY be omitted.
When present, the <SubjectConfirmationData> element MUST have a When present, the <SubjectConfirmationData> element MUST have a
Recipient attribute with a value indicating the token endpoint Recipient attribute with a value indicating the token endpoint
URL of the authorization server (or an acceptable alias). The URL of the authorization server (or an acceptable alias). The
authorization server MUST verify that the value of the Recipient authorization server MUST verify that the value of the Recipient
attribute matches the token endpoint URL (or an acceptable attribute matches the token endpoint URL (or an acceptable
alias) to which the Assertion was delivered. The alias) to which the Assertion was delivered. The
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invalidates the individual <SubjectConfirmation>. The invalidates the individual <SubjectConfirmation>. The
authorization server MAY reject Assertions with a NotOnOrAfter authorization server MAY reject Assertions with a NotOnOrAfter
instant that is unreasonably far in the future. The instant that is unreasonably far in the future. The
authorization server MAY ensure that Bearer Assertions are not authorization server MAY ensure that Bearer Assertions are not
replayed, by maintaining the set of used ID values for the replayed, by maintaining the set of used ID values for the
length of time for which the Assertion would be considered valid length of time for which the Assertion would be considered valid
based on the applicable NotOnOrAfter instant. based on the applicable NotOnOrAfter instant.
7. If the Assertion issuer authenticated the subject, the Assertion 7. If the Assertion issuer authenticated the subject, the Assertion
SHOULD contain a single <AuthnStatement> representing that SHOULD contain a single <AuthnStatement> representing that
authentication event. authentication event. If the Assertion was issued with the
intention that the client act autonomously on behalf of the
8. If the Assertion was issued with the intention that the subject, an <AuthnStatement> SHOULD NOT be included and the
presenter act autonomously on behalf of the subject, an client presenting the assertion SHOULD be identified in the
<AuthnStatement> SHOULD NOT be included. The presenter SHOULD <NameID> or similar element in the <SubjectConfirmation>
be identified in the <NameID> or similar element in the element, or by other available means like SAML V2.0 Condition
<SubjectConfirmation> element, or by other available means like for Delegation Restriction [OASIS.saml-deleg-cs].
SAML V2.0 Condition for Delegation Restriction
[OASIS.saml-deleg-cs].
9. Other statements, in particular <AttributeStatement> elements, 8. Other statements, in particular <AttributeStatement> elements,
MAY be included in the Assertion. MAY be included in the Assertion.
10. The Assertion MUST be digitally signed or have a keyed message 9. The Assertion MUST be digitally signed or have a keyed message
digest applied by the issuer. The authorization server MUST digest applied by the issuer. The authorization server MUST
reject assertions with an invalid signature or keyed message reject assertions with an invalid signature or keyed message
digest. digest.
11. Encrypted elements MAY appear in place of their plain text 10. Encrypted elements MAY appear in place of their plain text
counterparts as defined in [OASIS.saml-core-2.0-os]. counterparts as defined in [OASIS.saml-core-2.0-os].
12. The authorization server MUST verify that the Assertion is valid 11. The authorization server MUST verify that the Assertion is valid
in all other respects per [OASIS.saml-core-2.0-os], such as (but in all other respects per [OASIS.saml-core-2.0-os], such as (but
not limited to) evaluating all content within the Conditions not limited to) evaluating all content within the Conditions
element including the NotOnOrAfter and NotBefore attributes, element including the NotOnOrAfter and NotBefore attributes,
rejecting unknown condition types, etc. rejecting unknown condition types, etc.
3.1. Authorization Grant Processing 3.1. Authorization Grant Processing
Assertion authorization grants may be used with or without client Assertion authorization grants may be used with or without client
authentication or identification. Whether or not client authentication or identification. Whether or not client
authentication is needed in conjunction with an assertion authentication is needed in conjunction with an assertion
authorization grant, as well as the supported types of client authorization grant, as well as the supported types of client
authentication, are policy decisions at the discretion of the authentication, are policy decisions at the discretion of the
authorization server. However, if client credentials are present in authorization server. However, if client credentials are present in
the request, the authorization server MUST validate them. the request, the authorization server MUST validate them.
If the Assertion is not valid, or its subject confirmation If the Assertion is not valid (including if its subject confirmation
requirements cannot be met, the authorization server MUST construct requirements cannot be met), the authorization server MUST construct
an error response as defined in OAuth 2.0 [RFC6749]. The value of an error response as defined in OAuth 2.0 [RFC6749]. The value of
the "error" parameter MUST be the "invalid_grant" error code. The the "error" parameter MUST be the "invalid_grant" error code. The
authorization server MAY include additional information regarding the authorization server MAY include additional information regarding the
reasons the Assertion was considered invalid using the reasons the Assertion was considered invalid using the
"error_description" or "error_uri" parameters. "error_description" or "error_uri" parameters.
For example: For example:
HTTP/1.1 400 Bad Request HTTP/1.1 400 Bad Request
Content-Type: application/json Content-Type: application/json
Cache-Control: no-store Cache-Control: no-store
{ {
"error":"invalid_grant", "error":"invalid_grant",
"error_description":"Audience validation failed" "error_description":"Audience validation failed"
} }
3.2. Client Authentication Processing 3.2. Client Authentication Processing
If the client Assertion is not valid, or its subject confirmation If the client Assertion is not valid (including if its subject
requirements cannot be met, the authorization server MUST construct confirmation requirements cannot be met), the authorization server
an error response as defined in OAuth 2.0 [RFC6749]. The value of MUST construct an error response as defined in OAuth 2.0 [RFC6749].
the "error" parameter MUST be the "invalid_client" error code. The The value of the "error" parameter MUST be the "invalid_client" error
authorization server MAY include additional information regarding the code. The authorization server MAY include additional information
reasons the Assertion was considered invalid using the regarding the reasons the Assertion was considered invalid using the
"error_description" or "error_uri" parameters. "error_description" or "error_uri" parameters.
4. Authorization Grant Example 4. Authorization Grant Example
Though non-normative, the following examples illustrate what a Though non-normative, the following examples illustrate what a
conforming Assertion and access token request would look like. conforming Assertion and access token request would look like.
The example shows an assertion issued and signed by the SAML Identity The example shows an assertion issued and signed by the SAML Identity
Provider identified as "https://saml-idp.example.com". The subject Provider identified as "https://saml-idp.example.com". The subject
of the assertion is identified by email address as of the assertion is identified by email address as
"brian@example.com", who authenticated to the Identity Provider by "brian@example.com", who authenticated to the Identity Provider by
means of a digital signature where the key was validated as part of means of a digital signature where the key was validated as part of
an X.509 Public Key Infrastructure. The intended audience of the an X.509 Public Key Infrastructure. The intended audience of the
assertion is "https://saml-sp.example.net", which is an identifier assertion is "https://saml-sp.example.net", which is an identifier
for a SAML Service Provider with which the authorization server for a SAML Service Provider with which the authorization server
identifies itself. The assertion is sent as part of an access token identifies itself. The assertion is sent as part of an access token
request to the authorization server's token endpoint at request to the authorization server's token endpoint at "https://
"https://authz.example.net/token.oauth2". authz.example.net/token.oauth2".
Below is an example SAML 2.0 Assertion (whitespace formatting is for Below is an example SAML 2.0 Assertion (whitespace formatting is for
display purposes only): display purposes only):
<Assertion IssueInstant="2010-10-01T20:07:34.619Z" <Assertion IssueInstant="2010-10-01T20:07:34.619Z"
ID="ef1xsbZxPV2oqjd7HTLRLIBlBb7" ID="ef1xsbZxPV2oqjd7HTLRLIBlBb7"
Version="2.0" Version="2.0"
xmlns="urn:oasis:names:tc:SAML:2.0:assertion"> xmlns="urn:oasis:names:tc:SAML:2.0:assertion">
<Issuer>https://saml-idp.example.com</Issuer> <Issuer>https://saml-idp.example.com</Issuer>
<ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"> <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#">
[...omitted for brevity...] [...omitted for brevity...]
</ds:Signature> </ds:Signature>
<Subject> <Subject>
<NameID <NameID
Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress"> Format="urn:oasis:names:tc:SAML:1.1:nameid-format:emailAddress">
brian@example.com brian@example.com
</NameID> </NameID>
<SubjectConfirmation <SubjectConfirmation
Method="urn:oasis:names:tc:SAML:2.0:cm:bearer"> Method="urn:oasis:names:tc:SAML:2.0:cm:bearer">
<SubjectConfirmationData <SubjectConfirmationData
NotOnOrAfter="2010-10-01T20:12:34.619Z" NotOnOrAfter="2010-10-01T20:12:34.619Z"
Recipient="https://authz.example.net/token.oauth2"/> Recipient="https://authz.example.net/token.oauth2"/>
</SubjectConfirmation> </SubjectConfirmation>
</Subject> </Subject>
<Conditions> <Conditions>
<AudienceRestriction> <AudienceRestriction>
<Audience>https://saml-sp.example.net</Audience> <Audience>https://saml-sp.example.net</Audience>
</AudienceRestriction> </AudienceRestriction>
</Conditions> </Conditions>
<AuthnStatement AuthnInstant="2010-10-01T20:07:34.371Z"> <AuthnStatement AuthnInstant="2010-10-01T20:07:34.371Z">
<AuthnContext> <AuthnContext>
<AuthnContextClassRef> <AuthnContextClassRef>
urn:oasis:names:tc:SAML:2.0:ac:classes:X509 urn:oasis:names:tc:SAML:2.0:ac:classes:X509
</AuthnContextClassRef> </AuthnContextClassRef>
</AuthnContext> </AuthnContext>
</AuthnStatement> </AuthnStatement>
</Assertion> </Assertion>
Figure 1: Example SAML 2.0 Assertion Figure 1: Example SAML 2.0 Assertion
To present the Assertion shown in the previous example as part of an To present the Assertion shown in the previous example as part of an
access token request, for example, the client might make the access token request, for example, the client might make the
following HTTPS request (with extra line breaks for display purposes following HTTPS request (with extra line breaks for display purposes
only): only):
POST /token.oauth2 HTTP/1.1 POST /token.oauth2 HTTP/1.1
Host: authz.example.net Host: authz.example.net
skipping to change at page 11, line 26 skipping to change at page 11, line 22
[...omitted for brevity...]aG5TdGF0ZW1lbnQ-PC9Bc3NlcnRpb24- [...omitted for brevity...]aG5TdGF0ZW1lbnQ-PC9Bc3NlcnRpb24-
Figure 2: Example Request Figure 2: Example Request
5. Interoperability Considerations 5. Interoperability Considerations
Agreement between system entities regarding identifiers, keys, and Agreement between system entities regarding identifiers, keys, and
endpoints is required in order to achieve interoperable deployments endpoints is required in order to achieve interoperable deployments
of this profile. Specific items that require agreement are as of this profile. Specific items that require agreement are as
follows: values for the issuer and audience identifiers, the location follows: values for the issuer and audience identifiers, the location
of the token endpoint, and the key used to apply and verify the of the token endpoint, the key used to apply and verify the digital
digital signature over the assertion. The exchange of such signature over the assertion, one-time use restrictions on
information is explicitly out of scope for this specification and assertions, maximum assertion lifetime allowed, and the specific
typical deployment of it will be done alongside existing SAML Web SSO subject and attribute requirements of the assertion. The exchange of
deployments that have already established a means of exchanging such such information is explicitly out of scope for this specification
information. Metadata for the OASIS Security Assertion Markup and typical deployment of it will be done alongside existing SAML Web
SSO deployments that have already established a means of exchanging
such information. Metadata for the OASIS Security Assertion Markup
Language (SAML) V2.0 [OASIS.saml-metadata-2.0-os] is one common Language (SAML) V2.0 [OASIS.saml-metadata-2.0-os] is one common
method of exchanging SAML related information about system entities. method of exchanging SAML related information about system entities.
6. Security Considerations 6. Security Considerations
No additional security considerations apply beyond those described The security considerations described within the Assertion Framework
within The OAuth 2.0 Authorization Framework [RFC6749], the Assertion for OAuth 2.0 Client Authentication and Authorization Grants
Framework for OAuth 2.0 Client Authentication and Authorization [I-D.ietf-oauth-assertions], The OAuth 2.0 Authorization Framework
Grants [I-D.ietf-oauth-assertions], and the Security and Privacy [RFC6749], and the Security and Privacy Considerations for the OASIS
Considerations for the OASIS Security Assertion Markup Language Security Assertion Markup Language (SAML) V2.0
(SAML) V2.0 [OASIS.saml-sec-consider-2.0-os] specifications. [OASIS.saml-sec-consider-2.0-os] specifications are all applicable to
this document.
The specification does not mandate replay protection for the SAML
assertion usage for either the authorization grant or for client
authentication. It is an optional feature, which implementations may
employ at their own discretion.
7. IANA Considerations 7. IANA Considerations
7.1. Sub-Namespace Registration of 7.1. Sub-Namespace Registration of urn:ietf:params:oauth:grant-
urn:ietf:params:oauth:grant-type:saml2-bearer type:saml2-bearer
This is a request to IANA to please register the value This is a request to IANA to please register the value "grant-
"grant-type:saml2-bearer" in the registry urn:ietf:params:oauth type:saml2-bearer" in the registry urn:ietf:params:oauth established
established in An IETF URN Sub-Namespace for OAuth [RFC6755]. in An IETF URN Sub-Namespace for OAuth [RFC6755].
o URN: urn:ietf:params:oauth:grant-type:saml2-bearer o URN: urn:ietf:params:oauth:grant-type:saml2-bearer
o Common Name: SAML 2.0 Bearer Assertion Grant Type Profile for o Common Name: SAML 2.0 Bearer Assertion Grant Type Profile for
OAuth 2.0 OAuth 2.0
o Change controller: IETF o Change controller: IETF
o Specification Document: [[this document]] o Specification Document: [[this document]]
7.2. Sub-Namespace Registration of 7.2. Sub-Namespace Registration of urn:ietf:params:oauth:client-
urn:ietf:params:oauth:client-assertion-type:saml2-bearer assertion-type:saml2-bearer
This is a request to IANA to please register the value This is a request to IANA to please register the value "client-
"client-assertion-type:saml2-bearer" in the registry assertion-type:saml2-bearer" in the registry urn:ietf:params:oauth
urn:ietf:params:oauth established in An IETF URN Sub-Namespace for established in An IETF URN Sub-Namespace for OAuth [RFC6755].
OAuth [RFC6755].
o URN: urn:ietf:params:oauth:client-assertion-type:saml2-bearer o URN: urn:ietf:params:oauth:client-assertion-type:saml2-bearer
o Common Name: SAML 2.0 Bearer Assertion Profile for OAuth 2.0 o Common Name: SAML 2.0 Bearer Assertion Profile for OAuth 2.0
Client Authentication Client Authentication
o Change controller: IETF o Change controller: IETF
o Specification Document: [[this document]] o Specification Document: [[this document]]
8. References 8. References
8.1. Normative References 8.1. Normative References
[I-D.ietf-oauth-assertions] [I-D.ietf-oauth-assertions]
Campbell, B., Mortimore, C., Jones, M., and Y. Goland, Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
"Assertion Framework for OAuth 2.0 Client Authentication "Assertion Framework for OAuth 2.0 Client Authentication
and Authorization Grants", draft-ietf-oauth-assertions and Authorization Grants", draft-ietf-oauth-assertions
(work in progress), July 2013. (work in progress), December 2013.
[OASIS.saml-core-2.0-os] [OASIS.saml-core-2.0-os]
Cantor, S., Kemp, J., Philpott, R., and E. Maler, Cantor, S., Kemp, J., Philpott, R., and E. Maler,
"Assertions and Protocol for the OASIS Security Assertion "Assertions and Protocol for the OASIS Security Assertion
Markup Language (SAML) V2.0", OASIS Standard saml-core- Markup Language (SAML) V2.0", OASIS Standard saml-
2.0-os, March 2005. core-2.0-os, March 2005.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66, RFC
RFC 3986, January 2005. 3986, January 2005.
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, October 2006. Encodings", RFC 4648, October 2006.
[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", [RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", RFC
RFC 6749, October 2012. 6749, October 2012.
[RFC6755] Campbell, B. and H. Tschofenig, "An IETF URN Sub-Namespace [RFC6755] Campbell, B. and H. Tschofenig, "An IETF URN Sub-Namespace
for OAuth", RFC 6755, October 2012. for OAuth", RFC 6755, October 2012.
8.2. Informative References 8.2. Informative References
[OASIS.saml-deleg-cs] [OASIS.saml-deleg-cs]
Cantor, S., Ed., "SAML V2.0 Condition for Delegation Cantor, S., Ed., "SAML V2.0 Condition for Delegation
Restriction", Nov 2009. Restriction", Nov 2009.
[OASIS.saml-metadata-2.0-os] [OASIS.saml-metadata-2.0-os]
Cantor, S., Moreh, J., Philpott, R., and E. Maler, Cantor, S., Moreh, J., Philpott, R., and E. Maler,
"Metadata for the Security Assertion Markup Language "Metadata for the Security Assertion Markup Language
(SAML) V2.0", OASIS Standard saml-metadata-2.0-os, (SAML) V2.0", OASIS Standard saml-metadata-2.0-os, March
March 2005. 2005.
[OASIS.saml-profiles-2.0-os] [OASIS.saml-profiles-2.0-os]
Hughes, J., Cantor, S., Hodges, J., Hirsch, F., Mishra, Hughes, J., Cantor, S., Hodges, J., Hirsch, F., Mishra,
P., Philpott, R., and E. Maler, "Profiles for the OASIS P., Philpott, R., and E. Maler, "Profiles for the OASIS
Security Assertion Markup Language (SAML) V2.0", OASIS Security Assertion Markup Language (SAML) V2.0", OASIS
Standard OASIS.saml-profiles-2.0-os, March 2005. Standard OASIS.saml-profiles-2.0-os, March 2005.
[OASIS.saml-sec-consider-2.0-os] [OASIS.saml-sec-consider-2.0-os]
Hirsch, F., Philpott, R., and E. Maler, "Security and Hirsch, F., Philpott, R., and E. Maler, "Security and
Privacy Considerations for the OASIS Security Markup Privacy Considerations for the OASIS Security Markup
Language (SAML) V2.0", OASIS Standard saml-sec-consider- Language (SAML) V2.0", OASIS Standard saml-sec-
2.0-os, March 2005. consider-2.0-os, March 2005.
[W3C.REC-html401-19991224] [W3C.REC-html401-19991224]
Hors, A., Raggett, D., and I. Jacobs, "HTML 4.01 Hors, A., Raggett, D., and I. Jacobs, "HTML 4.01
Specification", World Wide Web Consortium Specification", World Wide Web Consortium Recommendation
Recommendation REC-html401-19991224, December 1999, REC-html401-19991224, December 1999,
<http://www.w3.org/TR/1999/REC-html401-19991224>. <http://www.w3.org/TR/1999/REC-html401-19991224>.
Appendix A. Acknowledgements Appendix A. Acknowledgements
The following people contributed wording and concepts to this The following people contributed wording and concepts to this
document: Paul Madsen, Patrick Harding, Peter Motykowski, Eran document: Paul Madsen, Patrick Harding, Peter Motykowski, Eran
Hammer, Peter Saint-Andre, Ian Barnett, Eric Fazendin, Torsten Hammer, Peter Saint-Andre, Ian Barnett, Eric Fazendin, Torsten
Lodderstedt, Susan Harper, Scott Tomilson, Scott Cantor, Hannes Lodderstedt, Susan Harper, Scott Tomilson, Scott Cantor, Hannes
Tschofenig, David Waite, Phil Hunt, and Mukesh Bhatnagar. Tschofenig, David Waite, Phil Hunt, and Mukesh Bhatnagar.
Appendix B. Document History Appendix B. Document History
[[ to be removed by RFC editor before publication as an RFC ]] [[ to be removed by RFC editor before publication as an RFC ]]
draft-ietf-oauth-saml2-bearer-18
o Clean up language around subject per http://www.ietf.org/mail-
archive/web/oauth/current/msg12254.html.
o As suggested in http://www.ietf.org/mail-archive/web/oauth/current
/msg12253.html stated that "In the absence of an application
profile specifying otherwise, compliant applications MUST compare
the audience/issuer values using the Simple String Comparison
method defined in Section 6.2.1 of RFC 3986."
o Clarify the potentially confusing language about the AS confirming
the assertion http://www.ietf.org/mail-archive/web/oauth/current/
msg12255.html.
o Combine the two items about AuthnStatement and drop the word
presenter as discussed in http://www.ietf.org/mail-archive/web/
oauth/current/msg12257.html.
o Added one-time use, maximum lifetime, and specific subject and
attribute requirements to Interoperability Considerations based on
http://www.ietf.org/mail-archive/web/oauth/current/msg12252.html.
o Reword security considerations and mention that replay protection
is not mandated based on http://www.ietf.org/mail-archive/web/
oauth/current/msg12259.html.
draft-ietf-oauth-saml2-bearer-17 draft-ietf-oauth-saml2-bearer-17
o Stated that issuer and audience values SHOULD be compared using o Stated that issuer and audience values SHOULD be compared using
the Simple String Comparison method defined in Section 6.2.1 of the Simple String Comparison method defined in Section 6.2.1 of
RFC 3986 unless otherwise specified by the application. RFC 3986 unless otherwise specified by the application.
draft-ietf-oauth-saml2-bearer-16 draft-ietf-oauth-saml2-bearer-16
o Changed title from "SAML 2.0 Bearer Assertion Profiles for OAuth o Changed title from "SAML 2.0 Bearer Assertion Profiles for OAuth
2.0" to "SAML 2.0 Profile for OAuth 2.0 Client Authentication and 2.0" to "SAML 2.0 Profile for OAuth 2.0 Client Authentication and
Authorization Grants" to be more explicit about the scope of the Authorization Grants" to be more explicit about the scope of the
document per document per http://www.ietf.org/mail-archive/web/oauth/current/
http://www.ietf.org/mail-archive/web/oauth/current/msg11063.html. msg11063.html.
o Fixed typo in text identifying the presenter from "or similar o Fixed typo in text identifying the presenter from "or similar
element, the" to "or similar element in the". element, the" to "or similar element in the".
o Numbered the list of processing rules. o Numbered the list of processing rules.
o Smallish editorial cleanups to try and improve readability and o Smallish editorial cleanups to try and improve readability and
comprehensibility. comprehensibility.
o Cleaner split out of the processing rules in cases where they o Cleaner split out of the processing rules in cases where they
skipping to change at page 15, line 5 skipping to change at page 15, line 35
to SAML Metadata. to SAML Metadata.
o Added more explanatory context to the example in Section 4. o Added more explanatory context to the example in Section 4.
draft-ietf-oauth-saml2-bearer-15 draft-ietf-oauth-saml2-bearer-15
o Reference RFC 6749 and RFC 6755. o Reference RFC 6749 and RFC 6755.
o Update draft-ietf-oauth-assertions reference to -06. o Update draft-ietf-oauth-assertions reference to -06.
o Remove extraneous word per o Remove extraneous word per http://www.ietf.org/mail-archive/web/
http://www.ietf.org/mail-archive/web/oauth/current/msg10055.html oauth/current/msg10055.html
draft-ietf-oauth-saml2-bearer-14 draft-ietf-oauth-saml2-bearer-14
o Add more text to intro explaining that an assertion grant type can o Add more text to intro explaining that an assertion grant type can
be used with or without client authentication/identification and be used with or without client authentication/identification and
that client assertion authentication is nothing more than an that client assertion authentication is nothing more than an
alternative way for a client to authenticate to the token endpoint alternative way for a client to authenticate to the token endpoint
o Add examples to Sections 2.1 and 2.2 o Add examples to Sections 2.1 and 2.2
skipping to change at page 15, line 42 skipping to change at page 16, line 25
nothing) nothing)
draft-ietf-oauth-saml2-bearer-12 draft-ietf-oauth-saml2-bearer-12
o updated reference to draft-ietf-oauth-v2 from -25 to -26 and o updated reference to draft-ietf-oauth-v2 from -25 to -26 and
draft-ietf-oauth-assertions from -02 to -03 draft-ietf-oauth-assertions from -02 to -03
draft-ietf-oauth-saml2-bearer-11 draft-ietf-oauth-saml2-bearer-11
o Removed text about limited lifetime access tokens and the SHOULD o Removed text about limited lifetime access tokens and the SHOULD
NOT on issuing refresh tokens. The text was moved to NOT on issuing refresh tokens. The text was moved to draft-ietf-
draft-ietf-oauth-assertions-02 and somewhat modified per oauth-assertions-02 and somewhat modified per http://www.ietf.org/
http://www.ietf.org/mail-archive/web/oauth/current/msg08298.html. mail-archive/web/oauth/current/msg08298.html.
o Fixed typo/missing word per o Fixed typo/missing word per http://www.ietf.org/mail-archive/web/
http://www.ietf.org/mail-archive/web/oauth/current/msg08733.html. oauth/current/msg08733.html.
o Added Terminology section. o Added Terminology section.
draft-ietf-oauth-saml2-bearer-10 draft-ietf-oauth-saml2-bearer-10
o fix a spelling mistake o fix a spelling mistake
draft-ietf-oauth-saml2-bearer-09 draft-ietf-oauth-saml2-bearer-09
o Attempt to address an ambiguity around validation requirements o Attempt to address an ambiguity around validation requirements
when the Conditions element contain a NotOnOrAfter and when the Conditions element contain a NotOnOrAfter and
SubjectConfirmation/SubjectConfirmationData does too. Basically SubjectConfirmation/SubjectConfirmationData does too. Basically
it needs to have at least one bearer SubjectConfirmation element it needs to have at least one bearer SubjectConfirmation element
but that element can omit SubjectConfirmationData, if Conditions but that element can omit SubjectConfirmationData, if Conditions
has an expiry on it. Otherwise, a valid SubjectConfirmation must has an expiry on it. Otherwise, a valid SubjectConfirmation must
skipping to change at page 16, line 29 skipping to change at page 17, line 13
though it's implied by schema) though it's implied by schema)
o fix a typo o fix a typo
draft-ietf-oauth-saml2-bearer-08 draft-ietf-oauth-saml2-bearer-08
o fix some typos o fix some typos
draft-ietf-oauth-saml2-bearer-07 draft-ietf-oauth-saml2-bearer-07
o update reference from draft-campbell-oauth-urn-sub-ns to o update reference from draft-campbell-oauth-urn-sub-ns to draft-
draft-ietf-oauth-urn-sub-ns ietf-oauth-urn-sub-ns
o Updated to reference draft-ietf-oauth-v2-20 o Updated to reference draft-ietf-oauth-v2-20
draft-ietf-oauth-saml2-bearer-06 draft-ietf-oauth-saml2-bearer-06
o Fix three typos NamseID->NameID and (2x) Namspace->Namespace o Fix three typos NamseID->NameID and (2x) Namspace->Namespace
draft-ietf-oauth-saml2-bearer-05 draft-ietf-oauth-saml2-bearer-05
o Allow for subject confirmation data to be optional when Conditions o Allow for subject confirmation data to be optional when Conditions
contain audience and NotOnOrAfter contain audience and NotOnOrAfter
o Rework most of the spec to profile draft-ietf-oauth-assertions for o Rework most of the spec to profile draft-ietf-oauth-assertions for
both authn and authz including (but not limited to): both authn and authz including (but not limited to):
* remove requirement for issuer to be * remove requirement for issuer to be urn:oasis:names:tc:SAML:2.0
urn:oasis:names:tc:SAML:2.0:nameid-format:entity :nameid-format:entity
* change wording on Subject requirements * change wording on Subject requirements
o using a MAY, explicitly say that the Audience can be token o using a MAY, explicitly say that the Audience can be token
endpoint URL of the authorization server endpoint URL of the authorization server
o Change title to be more generic (allowing for client authn too) o Change title to be more generic (allowing for client authn too)
o added client authentication to the abstract o added client authentication to the abstract
o register and use urn:ietf:params:oauth:grant-type:saml2-bearer for o register and use urn:ietf:params:oauth:grant-type:saml2-bearer for
grant type rather than http://oauth.net/grant_type/saml/2.0/bearer grant type rather than http://oauth.net/grant_type/saml/2.0/bearer
o register urn:ietf:params:oauth:client-assertion-type:saml2-bearer o register urn:ietf:params:oauth:client-assertion-type:saml2-bearer
o remove scope parameter as it is defined in o remove scope parameter as it is defined in http://tools.ietf.org/
http://tools.ietf.org/html/draft-ietf-oauth-assertions html/draft-ietf-oauth-assertions
o remove assertion param registration because it [should] be in o remove assertion param registration because it [should] be in
http://tools.ietf.org/html/draft-ietf-oauth-assertions http://tools.ietf.org/html/draft-ietf-oauth-assertions
o fix typo(s) and update/add references o fix typo(s) and update/add references
draft-ietf-oauth-saml2-bearer-04 draft-ietf-oauth-saml2-bearer-04
o Changed the grant_type URI from o Changed the grant_type URI from "http://oauth.net/grant_type/
"http://oauth.net/grant_type/assertion/saml/2.0/bearer" to assertion/saml/2.0/bearer" to "http://oauth.net/grant_type/saml/
"http://oauth.net/grant_type/saml/2.0/bearer" - dropping the word 2.0/bearer" - dropping the word assertion from the path. Recent
assertion from the path. Recent versions of draft-ietf-oauth-v2 versions of draft-ietf-oauth-v2 no longer refer to extension
no longer refer to extension grants using the word assertion so grants using the word assertion so this URI is more reflective of
this URI is more reflective of that. It also more closely aligns that. It also more closely aligns with the grant type URI in
with the grant type URI in draft-jones-oauth-jwt-bearer-00 which draft-jones-oauth-jwt-bearer-00 which is "http://oauth.net/
is "http://oauth.net/grant_type/jwt/1.0/bearer". grant_type/jwt/1.0/bearer".
o Added "case sensitive" to scope definition to align with o Added "case sensitive" to scope definition to align with draft-
draft-ietf-oauth-v2-15/16. ietf-oauth-v2-15/16.
o Updated to reference draft-ietf-oauth-v2-16 o Updated to reference draft-ietf-oauth-v2-16
draft-ietf-oauth-saml2-bearer-03 draft-ietf-oauth-saml2-bearer-03
o Cleanup of some editorial issues. o Cleanup of some editorial issues.
draft-ietf-oauth-saml2-bearer-02 draft-ietf-oauth-saml2-bearer-02
o Added scope parameter with text copied from draft-ietf-oauth-v2-12 o Added scope parameter with text copied from draft-ietf-oauth-v2-12
(the reorg of draft-ietf-oauth-v2-12 made it so scope wasn't (the reorg of draft-ietf-oauth-v2-12 made it so scope wasn't
really inherited by this spec anymore) really inherited by this spec anymore)
o Change definition of the assertion parameter to be more generally o Change definition of the assertion parameter to be more generally
applicable per the suggestion near the end of applicable per the suggestion near the end of http://www.ietf.org/
http://www.ietf.org/mail-archive/web/oauth/current/msg05253.html mail-archive/web/oauth/current/msg05253.html
o Editorial changes based on feedback o Editorial changes based on feedback
draft-ietf-oauth-saml2-bearer-01 draft-ietf-oauth-saml2-bearer-01
o Update spec name when referencing draft-ietf-oauth-v2 (The OAuth o Update spec name when referencing draft-ietf-oauth-v2 (The OAuth
2.0 Protocol Framework -> The OAuth 2.0 Authorization Protocol) 2.0 Protocol Framework -> The OAuth 2.0 Authorization Protocol)
o Update wording in Introduction to talk about extension grant types o Update wording in Introduction to talk about extension grant types
rather than the assertion grant type which is a term no longer rather than the assertion grant type which is a term no longer
skipping to change at page 19, line 18 skipping to change at page 19, line 46
o Added some wording about identifying the client when the subject o Added some wording about identifying the client when the subject
hasn't directly authenticated including an informative reference hasn't directly authenticated including an informative reference
to SAML V2.0 Condition for Delegation Restriction. to SAML V2.0 Condition for Delegation Restriction.
o Added a few examples to the language about verifying that the o Added a few examples to the language about verifying that the
Assertion is valid in all other respects. Assertion is valid in all other respects.
o Added some wording to the introduction about the similarities to o Added some wording to the introduction about the similarities to
Web SSO in the format and processing rules Web SSO in the format and processing rules
o Changed the grant_type (was assertion_type) URI from o Changed the grant_type (was assertion_type) URI from http://
http://oauth.net/assertion_type/saml/2.0/bearer to oauth.net/assertion_type/saml/2.0/bearer to http://oauth.net/
http://oauth.net/grant_type/assertion/saml/2.0/bearer grant_type/assertion/saml/2.0/bearer
o Changed title to include "Grant Type" in it. o Changed title to include "Grant Type" in it.
o Editorial updates based on feedback from the WG and others o Editorial updates based on feedback from the WG and others
(including capitalization of Assertion when referring to SAML). (including capitalization of Assertion when referring to SAML).
draft-campbell-oauth-saml-00 draft-campbell-oauth-saml-00
o Initial I-D o Initial I-D
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