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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: July 14, 2018 SUNET 6 S. Cantor 7 Shibboleth Consortium 8 January 10, 2018 10 The Entity Category SAML Attribute Types 11 draft-young-entity-category-06 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 https://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 July 14, 2018. 40 Copyright Notice 42 Copyright (c) 2018 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 (https://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 . . . . . . . . . . . . . . . . . . 4 58 3.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 3.2. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 4 60 3.3. Entity Category Example . . . . . . . . . . . . . . . . . 5 61 4. Entity Category Support Attribute . . . . . . . . . . . . . . 6 62 4.1. Syntax . . . . . . . . . . . . . . . . . . . . . . . . . 6 63 4.2. Semantics . . . . . . . . . . . . . . . . . . . . . . . . 7 64 4.3. Entity Category Support Example . . . . . . . . . . . . . 7 65 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 66 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 67 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 68 7.1. Normative References . . . . . . . . . . . . . . . . . . 9 69 7.2. Informative References . . . . . . . . . . . . . . . . . 10 70 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 11 71 Appendix B. Change Log (to be removed by RFC Editor before 72 publication) . . . . . . . . . . . . . . . . . . . . 11 73 B.1. Since draft-young-entity-category-05 . . . . . . . . . . 11 74 B.2. Since draft-young-entity-category-04 . . . . . . . . . . 11 75 B.3. Since draft-young-entity-category-03 . . . . . . . . . . 11 76 B.4. Since draft-young-entity-category-02 . . . . . . . . . . 11 77 B.5. Since draft-young-entity-category-01 . . . . . . . . . . 12 78 B.6. Since draft-young-entity-category-00 . . . . . . . . . . 12 79 B.7. Since draft-macedir-entity-category . . . . . . . . . . . 13 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 82 1. Introduction 84 This document describes a SAML attribute, referred to here as the 85 "entity category attribute", values of which represent entity types 86 or categories. When used with the SAML V2.0 Metadata Extension for 87 Entity Attributes [SAML2MetadataAttr] each such entity category 88 attribute value represents a claim that the entity thus labelled 89 meets the requirements of, and is asserted to be a member of, the 90 indicated category. 92 These category membership claims MAY be used by a relying party to 93 provision policy for release of attributes from an identity provider, 94 to influence user interface decisions such as those related to 95 identity provider discovery, or for any other purpose. In general, 96 the intended uses of any claim of membership in a given category will 97 depend on the details of the category's definition, and will often be 98 included as part of that definition. 100 Entity category attribute values are URIs, and this document does not 101 specify a controlled vocabulary. Category URIs may therefore be 102 defined by any appropriate authority without any requirement for 103 central registration. It is anticipated that other specifications 104 may provide management and discovery mechanisms for entity category 105 attribute values. 107 A second SAML attribute, referred to here as the "entity category 108 support attribute", contains URI values which represent claims that 109 an entity supports and/or interoperates with entities in a given 110 category or categories. These values, defined in conjunction with 111 specific entity category values, provide entities in a category with 112 the means to identify peer entities that wish to interact with them 113 in category-specific fashion. 115 This document does not specify any values either for the entity 116 category attribute or for the entity category support attribute. 118 1.1. REFEDS Document Process 120 The Research and Education Federations group ([REFEDS]) is the voice 121 that articulates the mutual needs of research and education identity 122 federations worldwide. It aims to represent the requirements of 123 research and education in the ever-growing space of access and 124 identity management. 126 From time to time REFEDS will wish to publish a document in the 127 Internet RFC series. Such documents will be published as part of the 128 RFC Independent Submission Stream [RFC4844]; however the REFEDS 129 working group sign-off process will have been followed for these 130 documents, as described in the REFEDS Participant's Agreement 131 [REFEDS.agreement]. 133 This document is a product of the REFEDS Working Group process. 135 2. Notation and Conventions 137 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 138 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 139 document are to be interpreted as described in RFC 2119 [BCP14]. 141 3. Entity Category Attribute 143 3.1. Syntax 145 Entity category attribute values MUST be URIs. It is RECOMMENDED 146 that http:-scheme or https:-scheme URLs are used, and further 147 RECOMMENDED that each such value resolves to a human-readable 148 document defining the category. 150 The entity category attribute MUST be encoded as a SAML 2.0 Attribute 151 element with @NameFormat urn:oasis:names:tc:SAML:2.0:attrname- 152 format:uri and @Name http://macedir.org/entity-category. 154 A SAML entity is associated with one or more categories by including 155 the Attribute element described here in the entity's metadata through 156 use of the [SAML2MetadataAttr] metadata extension, in which the 157 Attribute element is contained within an mdattr:EntityAttributes 158 element directly contained within an md:Extensions element directly 159 contained within the entity's md:EntityDescriptor. 161 The meaning of the entity category attribute is undefined by this 162 specification if it appears anywhere else within a metadata instance, 163 or within any other XML document. 165 If the entity category attribute Attribute element appears more than 166 once in the metadata for an entity, the combined set of associated 167 attribute values SHOULD be interpreted by relying parties as if they 168 all appeared within a single Attribute element. 170 3.2. Semantics 172 The presence of the entity category attribute within an entity's 173 entity attributes represents a series of claims (one for each 174 attribute value) that the entity is a member of each named category. 175 The precise semantics of such a claim depend on the definition of the 176 category itself. 178 An entity may be claimed to be a member of more than one category. 179 In this case, the entity is claimed to meet the requirements of each 180 category independently unless otherwise specified by the category 181 definitions themselves. 183 The definition of the concept of a category is intentionally not 184 addressed in this document, in order to leave it as general as 185 possible. However, to be useful, category definitions SHOULD include 186 the following as appropriate: 188 o A definition of the authorities who may validly assert membership 189 in the category. While membership in some categories may be self- 190 asserted informally by an entity's owner, others may need to be 191 validated by third parties such as the entity's home federation or 192 other registrar. 194 o A set of criteria by which an entity's membership in the category 195 can be objectively assessed. 197 o A definition of the processes by which valid authorities may 198 determine that an entity meets the category's membership criteria. 200 o A description of the anticipated uses for category membership by 201 relying parties. 203 o A statement indicating the applicability or otherwise of 204 membership of the entity category to different SAML role 205 descriptors, and any protocol support restrictions that may be 206 relevant. 208 Entity categories SHOULD NOT be used to indicate the certification 209 status of an entity regarding its conformance to the requirements of 210 an identity assurance framework. The [SAML2IDAssuranceProfile] 211 extension SHOULD be used for this purpose. 213 If significant changes are made to a category definition, the new 214 version of the category SHOULD be represented by a different category 215 URI so that the old and new versions can be distinguished by a 216 relying party. 218 No ordering relation is defined over entity category value URIs. 219 Entity category attribute value URIs MUST be treated as opaque 220 strings for the purpose of comparison. 222 3.3. Entity Category Example 223 225 226 228 231 http://example.org/category/dog 233 urn:oid:1.3.6.1.4.1.21829 234 235 236 237 ... 238 240 4. Entity Category Support Attribute 242 4.1. Syntax 244 Entity category support attribute values MUST be URIs. It is 245 RECOMMENDED that http:-scheme or https:-scheme URLs are used, and 246 further RECOMMENDED that each such value resolves to a human-readable 247 document defining the value's semantics. A given entity category 248 value MAY be associated with multiple support values in order to 249 allow for multiple forms of support, participation, or interoperation 250 with entities in the category. 252 The entity category support attribute MUST be encoded as a SAML 2.0 253 Attribute element with @NameFormat 254 urn:oasis:names:tc:SAML:2.0:attrname-format:uri and @Name 255 http://macedir.org/entity-category-support. 257 Claims that a SAML entity implements support for one or more 258 categories are represented by including the Attribute element 259 described here in the entity's metadata through use of the 260 [SAML2MetadataAttr] metadata extension, in which the Attribute 261 element is contained within an mdattr:EntityAttributes element 262 directly contained within an md:Extensions element directly contained 263 within the entity's md:EntityDescriptor. 265 The meaning of the entity category support attribute is undefined by 266 this specification if it appears anywhere else within a metadata 267 instance, or within any other XML document. 269 If the entity category support attribute Attribute element appears 270 more than once in the metadata for an entity, the combined set of 271 associated attribute values SHOULD be interpreted by relying parties 272 as if they all appeared within a single Attribute element. 274 4.2. Semantics 276 The presence of the entity category support attribute within an 277 entity's entity attributes represents a series of claims (one for 278 each attribute value) that the entity supports peer entities in a 279 category in a particular fashion. The precise semantics of such a 280 claim depend on the definition of the category support identifier 281 itself. Category support claims will often be defined to be self- 282 asserted. 284 An entity may be claimed to support more than one category. In this 285 case, the entity is claimed to meet the support requirements of each 286 category independently unless otherwise specified by the category 287 definitions themselves. 289 The definition of the concept of "support" for a category is 290 intentionally not addressed in this document, in order to leave it as 291 general as possible. It is assumed that entity category definitions 292 MAY define one or more support values signifying particular 293 definitions for "support" by peers as motivated by use cases arising 294 from the definition of the category itself. 296 A common case is expected to be the definition of a single support 297 value whose URI is identical to that defined for the category itself. 299 If significant changes are made to a category support definition, the 300 new version SHOULD be represented by a different category support URI 301 so that the old and new versions can be distinguished by a relying 302 party. 304 No ordering relation is defined over entity category value URIs. 305 Entity category attribute value URIs MUST be treated as opaque 306 strings for the purpose of comparison. 308 4.3. Entity Category Support Example 309 311 312 314 317 http://example.org/category/dog/basic 319 http://example.org/category/dog/advanced 321 urn:oid:1.3.6.1.4.1.21829 322 323 324 325 ... 326 328 5. IANA Considerations 330 This memo includes no request to IANA. 332 6. Security Considerations 334 The presence of the entity category attribute within an entity's 335 entity attributes represents a series of claims (one for each 336 attribute value) that the entity is a member of the named categories. 337 Before accepting and acting on such claims, any relying party needs 338 to establish, at a level of assurance sufficient for the intended 339 use, a chain of trust concluding that the claim is justified. 341 Some of the elements in such a chain of trust might include: 343 o The integrity of the metadata delivered to the relying party, as 344 for example assured by a digital signature. 346 o If the entity category attribute is carried within a signed 347 assertion, the assertion itself must be evaluated. 349 o The policies and procedures of the immediate source of the 350 metadata; in particular, any procedures the immediate source has 351 with regard to aggregation of metadata from other sources. 353 o The policies and procedures implemented by agents along the 354 publication path from the original metadata registrar: this may be 355 determined either by examination of the published procedures of 356 each agent in turn, or may be simplified if the entity metadata 357 includes publication path metadata in mdrpi:PublicationPath 358 elements as described in [SAML2MetadataRPI] section 2.3.1. 360 o The policies and procedures implemented by the original metadata 361 registrar. The registrar's identity may be known implicitly, or 362 may be determined from the entity metadata if it includes an 363 mdrpi:RegistrationInfo element and corresponding 364 @registrationAuthority attribute as described in 365 [SAML2MetadataRPI] section 2.1.1. 367 o The definition of the category itself; in particular, any 368 statements it makes about whether membership of the category may 369 be self-asserted, or may only be asserted by particular 370 authorities. 372 Although entity category support attribute values will often be 373 defined as self-asserted claims by the containing entity, the 374 provenance of the metadata remains relevant to a relying party's 375 decision to accept a claim of support as legitimate, and the specific 376 definition of a support claim will influence the assurance required 377 to act on it. 379 The conclusion that a claim of category membership or support is 380 justified and should be acted upon may require a determination of the 381 origin of the claim. This may not be necessary if the immediate 382 source of the metadata is trusted to such an extent that the trust 383 calculation is essentially delegated to it. 385 In many cases, a claim will be included in an entity's metadata by 386 the original metadata registrar on behalf of the entity's owner, and 387 the mdrpi:RegistrationInfo element's @registrationAuthority attribute 388 is available to carry the registrar's identity. However, any agent 389 that is part of the chain of custody between the original registrar 390 and the final relying party may have added, removed or transformed 391 claims according to local policy. For example, an agent charged with 392 redistributing metadata may remove claims it regards as 393 untrustworthy, or add others which were not already present if they 394 have value to its intended audience. 396 7. References 398 7.1. Normative References 400 [BCP14] Bradner, S., "Key words for use in RFCs to Indicate 401 Requirement Levels", BCP 14, RFC 2119, March 1997. 403 [SAML2MetadataAttr] 404 Cantor, S., Ed., "SAML V2.0 Metadata Extension for Entity 405 Attributes", August 2009, 406 . 408 [SAML2MetadataRPI] 409 La Joie, C., Ed., "SAML V2.0 Metadata Extensions for 410 Registration and Publication Information Version 1.0", 411 April 2012, 412 . 414 7.2. Informative References 416 [REFEDS] Research and Education Federations, "REFEDS Home Page", 417 . 419 [REFEDS.agreement] 420 Research and Education Federations, "REFEDS Participant's 421 Agreement", 422 . 424 [RFC4844] Daigle, L. and Internet Architecture Board, "The RFC 425 Series and RFC Editor", RFC 4844, July 2007. 427 [SAML2IDAssuranceProfile] 428 Morgan, RL., Ed., Madsen, P., Ed., and S. Cantor, Ed., 429 "SAML V2.0 Identity Assurance Profiles Version 1.0", 430 November 2010, . 433 Appendix A. Acknowledgements 435 This work has been a collaborative effort within the REFEDS and MACE- 436 Dir communities. Special thanks to (in no particular order): 438 o RL 'Bob' Morgan 440 o Ken Klingenstein 442 o Keith Hazelton 444 o Steven Olshansky 446 o Mikael Linden 448 o Nicole Harris 450 o Tom Scavo 452 Appendix B. Change Log (to be removed by RFC Editor before publication) 454 B.1. Since draft-young-entity-category-05 456 No substantive changes. 458 B.2. Since draft-young-entity-category-04 460 No substantive changes. 462 B.3. Since draft-young-entity-category-03 464 Additional improvements in response to IETF Gen-Art review: 466 o Section 3.2: additional SHOULD language recommending that category 467 definitions include applicability information for particular SAML 468 role descriptors. 470 o Section 3.2: added an informative reference to 471 [SAML2IDAssuranceProfile] and language recommending its use over 472 entity categories where appropriate. 474 B.4. Since draft-young-entity-category-02 476 Fix link to the REFEDS Participant's Agreement [REFEDS.agreement]. 478 Clarifications in response to IETF Gen-Art review: 480 o Section 1: make explicit the fact that we don't specify any values 481 of either attribute in this document. 483 o Section 3.1, Section 4.1: clarify that it is possible for 484 attribute values to appear within multiple Attribute elements, and 485 that this SHOULD be regarded as equivalent to combining them 486 within a single Attribute element. 488 o Section 3.2, Section 4.2: clarify the expectation that categories 489 are independent unless their definitions say otherwise. 491 o Section 3.2, Section 4.2: If significant changes are made to a 492 category definition, the new version of the category SHOULD be 493 represented by a different category URI *so that the old and new 494 versions can be distinguished by a relying party*. 496 o Section 3.2, Section 4.2: *No ordering relation is defined over 497 entity category value URIs.* Entity category attribute value URIs 498 MUST be treated as opaque strings *for the purpose of comparison*. 500 B.5. Since draft-young-entity-category-01 502 Changes from REFEDS consultation process: 504 1. Simplify title from "The Entity Category SAML Entity Metadata 505 Attribute Types" to "The Entity Category SAML Attribute Types". 507 2. Clarify the use of [SAML2MetadataRPI] in Section 6 by indicating 508 the elements and attributes to be used, and the sections of 509 [SAML2MetadataRPI] in which they are defined. 511 3. Remove any implication that category and category support claims 512 are necessarily being made "by" the entity itself. 514 4. Clarify that the origin of a category membership or support claim 515 may not always be the original registrar. 517 Grammar fix in Abstract. 519 Change the reference anchor for the SAML [SAML2MetadataRPI] 520 extension, as it now more commonly known as RPI than its original DRI 521 abbreviation. 523 B.6. Since draft-young-entity-category-00 525 Update affiliations for Leif Johansson and Scott Cantor. 527 Remove authors from acknowledgements. 529 Reorganize some of the introductory boilerplate sections. 531 B.7. Since draft-macedir-entity-category 533 Adopted as base for draft-young-entity-category-00. 535 Changed ipr from "pre5378Trust200902" to "trust200902" and submission 536 type from IETF to independent. 538 Designate Ian Young as editor for this version. Set more general 539 affiliation. 541 Modernised reference to RFC 2119 [BCP14] and moved that reference to 542 the introduction. 544 Adjusted layout of examples so that they don't exceed the RFC 545 standard line length. 547 Minor typographical nits but (intentionally) no substantive content 548 changes. 550 Authors' Addresses 552 Ian A. Young (editor) 553 Independent 555 EMail: ian@iay.org.uk 557 Leif Johansson 558 SUNET 560 EMail: leifj@sunet.se 562 Scott Cantor 563 Shibboleth Consortium 565 EMail: cantor.2@osu.edu