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Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 4844 (Obsoleted by RFC 8729) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group I. Young, Ed. 3 Internet-Draft Independent 4 Intended status: Informational L. Johansson 5 Expires: January 22, 2015 SUNET 6 S. Cantor 7 Shibboleth Consortium 8 July 21, 2014 10 The Entity Category SAML Attribute Types 11 draft-young-entity-category-02 13 Abstract 15 This document describes a SAML entity attribute which can be used to 16 assign category membership semantics to an entity, and a second 17 attribute for use in claiming interoperation with or support for 18 entities in such categories. 20 This document is a product of the Research and Education Federations 21 (REFEDS) Working Group process. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on January 22, 2015. 40 Copyright Notice 42 Copyright (c) 2014 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 55 1.1. REFEDS Document Process . . . . . . . . . . . . . . . . . 3 56 2. Notation and Conventions . . . . . . . . . . . . . . . . . . 3 57 3. Entity Category Attribute . . . . . . . . . . . . . . . . . . 3 58 3.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 3.2. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 4 60 3.3. Entity Category Example . . . . . . . . . . . . . . . . . 5 61 4. Entity Category Support Attribute . . . . . . . . . . . . . . 5 62 4.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 5 63 4.2. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 6 64 4.3. Entity Category Support Example . . . . . . . . . . . . . 6 65 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 66 6. Security Considerations . . . . . . . . . . . . . . . . . . . 7 67 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 68 7.1. Normative References . . . . . . . . . . . . . . . . . . 8 69 7.2. Informative References . . . . . . . . . . . . . . . . . 8 70 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 10 71 Appendix B. Change Log (to be removed by RFC Editor before 72 publication) . . . . . . . . . . . . . . . . . . . . 10 73 B.1. Since draft-young-entity-category-01 . . . . . . . . . . 10 74 B.2. Since draft-young-entity-category-00 . . . . . . . . . . 11 75 B.3. Since draft-macedir-entity-category . . . . . . . . . . . 11 77 1. Introduction 79 This document describes a SAML attribute, referred to here as the 80 "entity category attribute", values of which represent entity types 81 or categories. When used with the SAML V2.0 Metadata Extension for 82 Entity Attributes [SAML2MetadataAttr] each such entity category 83 attribute value represents a claim that the entity thus labelled 84 meets the requirements of, and is asserted to be a member of, the 85 indicated category. 87 These category membership claims MAY be used by a relying party to 88 provision policy for release of attributes from an identity provider, 89 to influence user interface decisions such as those related to 90 identity provider discovery, or for any other purpose. In general, 91 the intended uses of any claim of membership in a given category will 92 depend on the details of the category's definition, and will often be 93 included as part of that definition. 95 Entity category attribute values are URIs, and this document does not 96 specify a controlled vocabulary. Category URIs may therefore be 97 defined by any appropriate authority without any requirement for 98 central registration. It is anticipated that other specifications 99 may provide management and discovery mechanisms for entity category 100 attribute values. 102 A second SAML attribute, referred to here as the "entity category 103 support attribute", contains URI values which represent claims that 104 an entity supports and/or interoperates with entities in a given 105 category or categories. These values, defined in conjunction with 106 specific entity category values, provide entities in a category with 107 the means to identify peer entities that wish to interact with them 108 in category-specific fashion. 110 1.1. REFEDS Document Process 112 The Research and Education Federations group ([REFEDS]) is the voice 113 that articulates the mutual needs of research and education identity 114 federations worldwide. It aims to represent the requirements of 115 research and education in the ever-growing space of access and 116 identity management. 118 From time to time REFEDS will wish to publish a document in the 119 Internet RFC series. Such documents will be published as part of the 120 RFC Independent Submission Stream [RFC4844]; however the REFEDS 121 working group sign-off process will have been followed for these 122 documents, as described in the REFEDS Participant's Agreement 123 [REFEDS.agreement]. 125 This document is a product of the REFEDS Working Group process. 127 2. Notation and Conventions 129 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 130 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 131 document are to be interpreted as described in RFC 2119 [BCP14]. 133 3. Entity Category Attribute 135 3.1. Syntax 137 Entity category attribute values MUST be URIs. It is RECOMMENDED 138 that http:-scheme or https:-scheme URLs are used, and further 139 RECOMMENDED that each such value resolves to a human-readable 140 document defining the category. 142 The entity category attribute MUST be encoded as a SAML 2.0 Attribute 143 element with @NameFormat urn:oasis:names:tc:SAML:2.0:attrname- 144 format:uri and @Name http://macedir.org/entity-category. 146 A SAML entity is associated with one or more categories by including 147 the Attribute element described here in the entity's metadata through 148 use of the [SAML2MetadataAttr] metadata extension, in which the 149 Attribute element is contained within an mdattr:EntityAttributes 150 element directly contained within an md:Extensions element directly 151 contained within the entity's md:EntityDescriptor. The meaning of 152 the entity category attribute is undefined by this specification if 153 it appears anywhere else within a metadata instance, or within any 154 other XML document. 156 3.2. Semantics 158 The presence of the entity category attribute within an entity's 159 entity attributes represents a series of claims (one for each 160 attribute value) that the entity is a member of each named category. 161 The precise semantics of such a claim depend on the definition of the 162 category itself. 164 The definition of the concept of a category is intentionally not 165 addressed in this document, in order to leave it as general as 166 possible. However, to be useful, category definitions SHOULD include 167 the following as appropriate: 169 o A definition of the authorities who may validly assert membership 170 in the category. While membership in some categories may be self- 171 asserted informally by an entity's owner, others may need to be 172 validated by third parties such as the entity's home federation or 173 other registrar. 175 o A set of criteria by which an entity's membership in the category 176 can be objectively assessed. 178 o A definition of the processes by which valid authorities may 179 determine that an entity meets the category's membership criteria. 181 o A description of the anticipated uses for category membership by 182 relying parties. 184 If significant changes are made to a category definition, the new 185 version of the category SHOULD be represented by a different category 186 URI. 188 Entity category attribute value URIs MUST be treated as opaque 189 strings. 191 3.3. Entity Category Example 193 195 196 198 201 http://example.org/category/dog 203 urn:oid:1.3.6.1.4.1.21829 204 205 206 207 ... 208 210 4. Entity Category Support Attribute 212 4.1. Syntax 214 Entity category support attribute values MUST be URIs. It is 215 RECOMMENDED that http:-scheme or https:-scheme URLs are used, and 216 further RECOMMENDED that each such value resolves to a human-readable 217 document defining the value's semantics. A given entity category 218 value MAY be associated with multiple support values in order to 219 allow for multiple forms of support, participation, or interoperation 220 with entities in the category. 222 The entity category support attribute MUST be encoded as a SAML 2.0 223 Attribute element with @NameFormat 224 urn:oasis:names:tc:SAML:2.0:attrname-format:uri and @Name 225 http://macedir.org/entity-category-support. 227 Claims that a SAML entity implements support for one or more 228 categories are represented by including the Attribute element 229 described here in the entity's metadata through use of the 230 [SAML2MetadataAttr] metadata extension, in which the Attribute 231 element is contained within an mdattr:EntityAttributes element 232 directly contained within an md:Extensions element directly contained 233 within the entity's md:EntityDescriptor. The meaning of the entity 234 category support attribute is undefined by this specification if it 235 appears anywhere else within a metadata instance, or within any other 236 XML document. 238 4.2. Semantics 240 The presence of the entity category support attribute within an 241 entity's entity attributes represents a series of claims (one for 242 each attribute value) that the entity supports peer entities in a 243 category in a particular fashion. The precise semantics of such a 244 claim depend on the definition of the category support identifier 245 itself. Category support claims will often be defined to be self- 246 asserted. 248 The definition of the concept of "support" for a category is 249 intentionally not addressed in this document, in order to leave it as 250 general as possible. It is assumed that entity category definitions 251 MAY define one or more support values signifying particular 252 definitions for "support" by peers as motivated by use cases arising 253 from the definition of the category itself. 255 A common case is expected to be the definition of a single support 256 value whose URI is identical to that defined for the category itself. 258 If significant changes are made to a category support definition, the 259 new version SHOULD be represented by a different category support 260 URI. 262 Entity category support attribute value URIs MUST be treated as 263 opaque strings. 265 4.3. Entity Category Support Example 267 269 270 272 275 http://example.org/category/dog/basic 277 http://example.org/category/dog/advanced 279 urn:oid:1.3.6.1.4.1.21829 280 281 282 283 ... 284 286 5. IANA Considerations 288 This memo includes no request to IANA. 290 6. Security Considerations 292 The presence of the entity category attribute within an entity's 293 entity attributes represents a series of claims (one for each 294 attribute value) that the entity is a member of the named categories. 295 Before accepting and acting on such claims, any relying party needs 296 to establish, at a level of assurance sufficient for the intended 297 use, a chain of trust concluding that the claim is justified. 299 Some of the elements in such a chain of trust might include: 301 o The integrity of the metadata delivered to the relying party, as 302 for example assured by a digital signature. 304 o If the entity category attribute is carried within a signed 305 assertion, the assertion itself must be evaluated. 307 o The policies and procedures of the immediate source of the 308 metadata; in particular, any procedures the immediate source has 309 with regard to aggregation of metadata from other sources. 311 o The policies and procedures implemented by agents along the 312 publication path from the original metadata registrar: this may be 313 determined either by examination of the published procedures of 314 each agent in turn, or may be simplified if the entity metadata 315 includes publication path metadata in mdrpi:PublicationPath 316 elements as described in [SAML2MetadataRPI] section 2.3.1. 318 o The policies and procedures implemented by the original metadata 319 registrar. The registrar's identity may be known implicitly, or 320 may be determined from the entity metadata if it includes an 321 mdrpi:RegistrationInfo element and corresponding 322 @registrationAuthority attribute as described in 323 [SAML2MetadataRPI] section 2.1.1. 325 o The definition of the category itself; in particular, any 326 statements it makes about whether membership of the category may 327 be self-asserted, or may only be asserted by particular 328 authorities. 330 Although entity category support attribute values will often be 331 defined as self-asserted claims by the containing entity, the 332 provenance of the metadata remains relevant to a relying party's 333 decision to accept a claim of support as legitimate, and the specific 334 definition of a support claim will influence the assurance required 335 to act on it. 337 The conclusion that a claim of category membership or support is 338 justified and should be acted upon may require a determination of the 339 origin of the claim. This may not be necessary if the immediate 340 source of the metadata is trusted to such an extent that the trust 341 calculation is essentially delegated to it. 343 In many cases, a claim will be included in an entity's metadata by 344 the original metadata registrar on behalf of the entity's owner, and 345 the mdrpi:RegistrationInfo element's @registrationAuthority attribute 346 is available to carry the registrar's identity. However, any agent 347 that is part of the chain of custody between the original registrar 348 and the final relying party may have added, removed or transformed 349 claims according to local policy. For example, an agent charged with 350 redistributing metadata may remove claims it regards as 351 untrustworthy, or add others which were not already present if they 352 have value to its intended audience. 354 7. References 356 7.1. Normative References 358 [BCP14] Bradner, S., "Key words for use in RFCs to Indicate 359 Requirement Levels", BCP 14, RFC 2119, March 1997. 361 [SAML2MetadataAttr] 362 Cantor, S., Ed., "SAML V2.0 Metadata Extension for Entity 363 Attributes", August 2009, 364 . 366 [SAML2MetadataRPI] 367 La Joie, C., Ed., "SAML V2.0 Metadata Extensions for 368 Registration and Publication Information Version 1.0", 369 April 2012, 370 . 372 7.2. Informative References 374 [REFEDS] Research and Education Federations, "REFEDS Home Page", 375 . 377 [REFEDS.agreement] 378 Research and Education Federations, "REFEDS Participant's 379 Agreement", . 382 [RFC4844] Daigle, L. and Internet Architecture Board, "The RFC 383 Series and RFC Editor", RFC 4844, July 2007. 385 Appendix A. Acknowledgements 387 This work has been a collaborative effort within the REFEDS and MACE- 388 Dir communities. Special thanks to (in no particular order): 390 o RL 'Bob' Morgan 392 o Ken Klingenstein 394 o Keith Hazelton 396 o Steven Olshansky 398 o Mikael Linden 400 o Nicole Harris 402 o Tom Scavo 404 Appendix B. Change Log (to be removed by RFC Editor before publication) 406 B.1. Since draft-young-entity-category-01 408 Changes from REFEDS consultation process: 410 1. Simplify title from "The Entity Category SAML Entity Metadata 411 Attribute Types" to "The Entity Category SAML Attribute Types". 413 2. Clarify the use of [SAML2MetadataRPI] in Section 6 by indicating 414 the elements and attributes to be used, and the sections of 415 [SAML2MetadataRPI] in which they are defined. 417 3. Remove any implication that category and category support claims 418 are necessarily being made "by" the entity itself. 420 4. Clarify that the origin of a category membership or support claim 421 may not always be the original registrar. 423 Grammar fix in Abstract. 425 Change the reference anchor for the SAML [SAML2MetadataRPI] 426 extension, as it now more commonly known as RPI than its original DRI 427 abbreviation. 429 B.2. Since draft-young-entity-category-00 431 Update affiliations for Leif Johansson and Scott Cantor. 433 Remove authors from acknowledgements. 435 Reorganize some of the introductory boilerplate sections. 437 B.3. Since draft-macedir-entity-category 439 Adopted as base for draft-young-entity-category-00. 441 Changed ipr from "pre5378Trust200902" to "trust200902" and submission 442 type from IETF to independent. 444 Designate Ian Young as editor for this version. Set more general 445 affiliation. 447 Modernised reference to RFC 2119 [BCP14] and moved that reference to 448 the introduction. 450 Adjusted layout of examples so that they don't exceed the RFC 451 standard line length. 453 Minor typographical nits but (intentionally) no substantive content 454 changes. 456 Authors' Addresses 458 Ian A. Young (editor) 459 Independent 461 EMail: ian@iay.org.uk 463 Leif Johansson 464 SUNET 466 EMail: leifj@sunet.se 468 Scott Cantor 469 Shibboleth Consortium 471 EMail: cantor.2@osu.edu