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Subject: [security-services] Draft minutes for Tuesday PM
OASIS Security Services TC Feb. 3, 2004 Afternoon On the phone: Emily Xu, Tony Nadalin W-1: Session Support, John Kemp - Reference:: http://lists.oasis-open.org/archives/security-services/200402/msg00013.html - Proposal 1: Use assertion ID and validity period to represent the session and validity period. - Hal: Assertion ID is not really session ID, but used to identity session by the session authority. - No separate piece of XML to represent session in SAML protocol. - Authentication authority and session authority are the same. - Hal: Neither proposal extends life of session. - Scott: SP can treat new assertion as a continuation of a session if it wants. One purpose for relay state: session token. - Mike B: Use case for session with multiple authentication assertions? Hal: Sign on with password then later with certificate. - Ron: Does session have to be bound to an authentication event? - Hal: Objective is dynamic session termination. - Scott: Not a general purpose solution for accounting, message protection (e.g. Kerberos). - Validity period discussion - Hal: In artifact & post profile, assertion validity max time to initiate SSO (short lived), not length of session. - Prateek: Meant to be an introduction protocol. - Rob: Use local session policies after using assertion to initiate session. - Steve: Have to remember something about the session, e.g. assertion ID, and have some expiration on the stored data. - Scott: Always had IssueInstance for freshness control. - Mike B: Concern about SPs ignoring assertion/session expiration. - Prateek: IdP control over lifetime of assertion important. - Mike B: SPs have specific timeouts; user still logged in at IdP; need to force re-authentication. Hal: can be handled by proposals. - Prateek: Why not propagate session lifetime as well as assertion validity? Hint vs. enforce. Conformance behavior for SP. - Logout Proposal: Send logout message if principal logs out, session authority notifies participants. (ID-FF 1.2) - Ron: If message doesn't go through, can't log out. Best effort. - Scott: IdP batches all assertions it considers a session. - Scott: Case where rule can't exist: Web browser and phone log in; different sessions. - Hal: Participants should agree one way or another but be consistent. - Hal: SP can ask session to logout, SA can tell SPs when session is logged out. - Discussion on whether a SP can say "no" to a logout. - Hal: Session only for those who explicitly asked for it, so should only participate if can honor logout. - Rob: Hand off session to a legacy system with no way to end legacy session. - Discussion of polling for validity vs. waiting for logout messages. - Hal: Either IdPs have to keep track of which SPs have been given assertions, or SPs need to handle logouts for sessions they don't know about. - John: Could do what Liberty does with Session ID in authentication assertion. - Ron: What is SP state for session? Scott. etc: Assertion ID, maybe original assertion, maybe related local state. Hal: need to track touch time if care about idle time. - Motion by John: Incorporate ID-FF v1.2 logout protocol, with extension into SAML v2.0. - Seconded by Hal. - Discussion - Hal: Concern with using same logout message with different semantics. - Mike B: one way is logout notification, other way is logout request. - No objections.Motion carries. - Hypothetical motion: Use assertion ID as the session identifier. - Mike B: Why not use Liberty concept of session ID in the assertion? - John: More simple to use existing assertion ID than introduce additional elements. - Scott: Some problems with ID-FF sessions; required some cleanup; clean now. - Mike B: Would like convergence between Liberty and SAML. - John: Liberty providers would implement SAML 2.0. - Compromise proposal: use assertion ID and include session ID in authentication statement? - Ron: Prefer in Subject statement for other types of statements; John: was there originally. - Timeout Proposal (Hal): One max idle timeout for all SPs; individual shorter SP timeouts. - Central session authority (SA) keeps track of session activity. All SPs report touch time to SA (one way). SA keeps latest touch time. - If max idle timeout occurs, session logged out for all SPs. - If individual SP timeout occurs, session logged out for that SP. - R.L. "Bob": SA should notify SP if the session doesn't exist anymore. Ron: Touch time notification could need a response sometimes. - SA periodically scans touch times to find those older than max global timeout or individual SP timeout, then sends logout requests to SPs. - Steve: Desire more on demand update of touch time. User sends a browser request that exceeds local SP idle timeout; ask SA the last touch time, SA might poll other SPs. - Hal: concern about scaling - Irving & Scott: requirement for front channel binding. - Greg: Hybrid approach: SPs report touch time only when they see a user. - Steve: Issue with resource access through components with no SAML knowledge. - No agreement on next step. W-5: SSO Profile Enhancements, Prateek Mishra - Proposal 1: Replace SAML 1.1 profiles with ID-FF AuthnRequest: SP->IdP; AuthnResponse: IdP->SP - Proposal 2: Accept materials in section 3.2 for abstract AuthnRequest and AuthnResponse protocol. - Map AuthnRequest/Response to existing web SSO profiles. - John H: Not clear can use AuthnRequest for artifact. Scott: artifact represents a response. - Scott: Can't divorce AuthnResponse from the Liberty assertion. - Scott: Review of AuthnRequest schema - Extension: allows derivation of new types from AuthnRequest. - ProviderID: superfluous now that Issuer is in the SAML 2.0 request; will be dropped. - AffliationID: request authentication as part of an affiliation. - R. L. "Bob": collection of SPs - implicit SAML support requirement. - NameIDPolicy: enumerated type -- desired name ID and federation operations, e.g. use existing federated ID, but don't establish a new federation; Needs to be generalized for SAML. - Jeff: Need to be careful to have true convergence with Liberty, backwards compatibility with existing Liberty values. - Discussion about increasing protocol size. Agreement for now to keep one document for assertion and protocols. - ForceAuthn: IdP should try to interact with principal to re-authentication - IsPassive: don't interact with principal. Discussion of relation with ForceAuthn. - ProtocolProfile: which profile to use for the request; decomposes request and response profiles, but different profiles not used by anyone? - AssertionConsumerServiceID: used to identity the AssertionConsumerService URL; SP can have multiple such URLs. Example: regional consumers. - RequestAuthnContext: authentication requirements; statements of policies and procedures - RelayState: now in base request type. - Scoping: proxy use case - Consent: have obtained user consent for operation. - Liberty says request should be signed but does not require it. - Review of AuthnResponse schema - Extension - ProviderID -> Issuer - RelayState - Carries assertion as per base type. - Liberty requires assertions to be signed for use as security tokens. Not practical to sign both assertion and response. - Liberty assertion contains InResponseTo vs. SAML response. - Liberty assertion uses Audience (name of consuming SP) vs. SAML response Recipient (SP location URL). - Prateek moved to accept Proposal 1 and 2. Eve seconded. - Discussion - Tony: why totally get rid of SAML 1.1 profiles? - Prateek: Adopt abstract AuthnRequest-Response and then revisit concrete implementations. - Tony: concern about existing implementations. Irving: how different from existing implementations? - Scott: resulting architecture not too different. - Charles: Example of post profile, what would change would be response in the post. - Charles: One motivation is solution of "destination-first" problem? Prateek: yes. - Motion is to accept this as a starting point for subsequent work. - Motion carries by unanimous consent. W-5a: Enhanced Client Profiles, Frederick Hirsch - Goal: Bring solutions enabled by SAML to a wide variety of devices - Enhanced client or proxy (ECP): IdP- --- ECP ---- SP - ECP profile: - ECP request to SP - SP requests authn in response - ECP gets assertion from IdP - ECP returns assertion to SP - Profiles: - Legacy-SP (HTTP only for SP) = LECP - Reverse HTTP SOAP binding PAOS + LECP = PECP - PAOS: reverse-HTTP binding for SOAP, solicit-response message exchange pattern. - PAOS + LECP: eliminates custom AuthnRequest/Response envelopes, uses custom SOAP headers - Issue: use of PAOS + LECP as a general mechanism for SOAP clients. - Question on how agnostic proposal is to SOAP version. Scott: do we need normative spec language for SOAP 1.2? - Jeff:: what is depth of penetration of SOAP 1.2 in the marketplace? - Proposals: - Adopt LECP solution (draft 5). - Adopt PAOS + LECP solution (draft 1). - Integrate into SAML 2.0 bindings and profiles specs. - Frederick moved to accept proposals; John K. seconded. - Discussion of relation between these proposals and other proposals to be discussed later in this F2F. - Motion tabled. Discussion to resume tomorrow.