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'ID.ietf-sidr-arch') == Outdated reference: A later version (-05) exists of draft-ietf-sidr-rpki-algs-00 Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Individual Submission G. Huston 3 Internet-Draft G. Michaelson 4 Intended status: BCP APNIC 5 Expires: November 9, 2010 May 8, 2010 7 A Profile for AS Adjacency Attestation Objects 8 draft-huston-sidr-aao-profile-03.txt 10 Abstract 12 This document describes a profile for AS Adjacency Attestation 13 Objects (AAOs). An AAO is a digitally signed object that provides a 14 means of verifying that an AS holder has made an attestation that it 15 has a inter-domain routing adjacency with one or more other AS's, 16 with the associated inference that this AS is prepared to announce or 17 receive routes with these adjacent AS's in the inter-domain domain 18 environment. 20 Status of this Memo 22 This Internet-Draft is submitted in full conformance with the 23 provisions of BCP 78 and BCP 79. 25 Internet-Drafts are working documents of the Internet Engineering 26 Task Force (IETF). Note that other groups may also distribute 27 working documents as Internet-Drafts. The list of current Internet- 28 Drafts is at http://datatracker.ietf.org/drafts/current/. 30 Internet-Drafts are draft documents valid for a maximum of six months 31 and may be updated, replaced, or obsoleted by other documents at any 32 time. It is inappropriate to use Internet-Drafts as reference 33 material or to cite them other than as "work in progress." 35 This Internet-Draft will expire on November 9, 2010. 37 Copyright Notice 39 Copyright (c) 2010 IETF Trust and the persons identified as the 40 document authors. All rights reserved. 42 This document is subject to BCP 78 and the IETF Trust's Legal 43 Provisions Relating to IETF Documents 44 (http://trustee.ietf.org/license-info) in effect on the date of 45 publication of this document. Please review these documents 46 carefully, as they describe your rights and restrictions with respect 47 to this document. Code Components extracted from this document must 48 include Simplified BSD License text as described in Section 4.e of 49 the Trust Legal Provisions and are provided without warranty as 50 described in the Simplified BSD License. 52 Table of Contents 54 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 55 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 56 2. Semantic Interpretation of an AAO . . . . . . . . . . . . . . 3 57 3. Basic Format . . . . . . . . . . . . . . . . . . . . . . . . . 4 58 3.1. Signed-Data Content Type . . . . . . . . . . . . . . . . . 5 59 3.1.1. version . . . . . . . . . . . . . . . . . . . . . . . 5 60 3.1.2. digestAlgorithms . . . . . . . . . . . . . . . . . . . 5 61 3.1.3. encapContentInfo . . . . . . . . . . . . . . . . . . . 5 62 3.1.4. CertificateSet . . . . . . . . . . . . . . . . . . . . 7 63 3.1.5. certificates . . . . . . . . . . . . . . . . . . . . . 7 64 3.1.6. crls . . . . . . . . . . . . . . . . . . . . . . . . . 7 65 3.1.7. signerInfos . . . . . . . . . . . . . . . . . . . . . 7 66 4. AAO Validation . . . . . . . . . . . . . . . . . . . . . . . . 10 67 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 68 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 69 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 70 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 71 8.1. Normative References . . . . . . . . . . . . . . . . . . . 12 72 8.2. Informative References . . . . . . . . . . . . . . . . . . 13 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 75 1. Introduction 77 The primary purpose of the Internet IP Address and AS Number Resource 78 Public Key Infrastructure (RPKI) system [ID.ietf-sidr-arch] is to 79 improve routing security. As part of this security framework, a 80 mechanism is defined here to allow entities to verify that an AS 81 holder attests that is adjacent to one or more other AS's, with the 82 inference that it is prepared to announce routes to these adjacent 83 AS's in the inter-domain routing environment. An AS Adjacency 84 Attestation Object (AAO) provides this function. 86 An AAO is a digitally signed object that makes use of Cryptographic 87 Message Syntax (CMS) [RFC5652] as a standard encapsulation format. 88 CMS was chosen to take advantage of existing open source software 89 available for processing messages in this format. 91 The AAO is an attestation, made and issued by the local AS holder, 92 that the local AS is an inter-domain routing peer with each of the 93 AS's that are enumerated in an associated AS list contained in the 94 AAO. An AAO is a two part structure, containing the local AS and a 95 list of adjacent AS's. The AAO is signed by a an End Entity (EE) 96 Resource Certificate that has the local AS as the value of its 97 [RFC3779] AS number resource extension. 99 1.1. Terminology 101 It is assumed that the reader is familiar with the terms and concepts 102 described in "Internet X.509 Public Key Infrastructure Certificate 103 and Certificate Revocation List (CRL) Profile" [RFC5280], "X.509 104 Extensions for IP Addresses and AS Identifiers" [RFC3779], and BGP-4 105 [RFC4271] 107 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 108 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 109 document are to be interpreted as described in RFC 2119. 111 2. Semantic Interpretation of an AAO 113 An AAO is an attestation on the part of a AS holder that it supports 114 currently active inter-domain routing adjacencies to each of the AS's 115 listed in the AAO. The AAO does not list any prefixes that may be 116 announced to the adjacent AS's either directly or indirectly. The 117 AAO also does not list any local routing policies that have been 118 applied to the routes that are advertised across this adjacency, nor 119 any routing policies that may be applied to routes that are learned 120 from this adjacency. 122 The AAO is intended to provide "closure" with respect to 123 interpretation of the AAO by relying parties, to the extent that if a 124 valid AAO exists for a local AS, then from the perspective of that 125 local AS all adjacencies with those AS's listed in the valid AAO can 126 be regarded as "valid" and any other adjacency from the perspective 127 of the local AS can be regarded as potentially "invalid". In other 128 words an AAO is an attestation of adjacency with the AS's listed in 129 the AAO and an implicit attestation of the denial of adjacency with 130 all other AS's. 132 Where an AS holder has published two or more valid AAO's, the set of 133 "valid" adjacent AS's refers to the union of the lists of adjacent 134 AS's and all other AS's can be regarded as "invalid" from the 135 perspective of the local AS. 137 A relying party may infer from a valid AAO that the signing AS holder 138 may have the intent to advertise route objects across this inter-AS 139 routing adjacency, and may be prepared to learn route objects that 140 are passed to it from the adjacent AS. The AAO does not described 141 which routes may be announced across a corresponding inter-AS routing 142 adjacency. 144 It is noted that an AAO is an asymmetric assertion, where one AS is 145 asserting that an inter-domain routing adjacency with another AS 146 exists. It should also be noted that this assertion is not 147 explicitly acknowledged by the remote AS in the context of a single 148 issued AAO. Relying parties may elect to place greater levels of 149 confidence in the existence of an inter-domain routing adjacency when 150 both AS's have signed and published AAO objects that contain mutual 151 references. 153 It is also noted that there is a subtle distinction that could be 154 drawn here between the appropriate semantic interpretation a pair of 155 unilateral assertions of adjacency using two AAOs and a combined 156 assertion of adjacency where both AS's sign a single attestation of 157 the existence of an inter-domain routing adjacency between these 158 AS's. Such a combined approach, using a single assertion with two 159 digital signatures, is not defined in this document. 161 3. Basic Format 163 Using CMS syntax, an AAO is a type of signed-data object. The 164 general format of a CMS object is: 166 ContentInfo ::= SEQUENCE { 167 contentType ContentType, 168 content [0] EXPLICIT ANY DEFINED BY contentType } 170 ContentType ::= OBJECT IDENTIFIER 172 As a AAO is a signed-data object, it uses the corresponding OID, 173 1.2.840.113549.1.7.2. [RFC5652] 175 3.1. Signed-Data Content Type 177 According to the CMS standard, the signed-data content type shall 178 have ASN.1 type SignedData: 180 SignedData ::= SEQUENCE { 181 version CMSVersion, 182 digestAlgorithms DigestAlgorithmIdentifiers, 183 encapContentInfo EncapsulatedContentInfo, 184 certificates [0] IMPLICIT CertificateSet OPTIONAL, 185 crls [1] IMPLICIT RevocationInfoChoices OPTIONAL, 186 signerInfos SignerInfos } 188 DigestAlgorithmIdentifiers ::= SET OF DigestAlgorithmIdentifier 190 SignerInfos ::= SET OF SignerInfo 192 3.1.1. version 194 The version is the syntax version number. It MUST be 3, 195 corresponding to the signerInfo structure having version number 3. 197 3.1.2. digestAlgorithms 199 The digestAlgorithms set contains the OIDs of the digest algorithm(s) 200 used in signing the encapsulated content. This set MUST conform to 201 the RPKI Algorithms and Key Size Profile specification 202 [ID.sidr-rpki-algs]. 204 3.1.3. encapContentInfo 206 encapContentInfo is the signed content, consisting of a content type 207 identifier and the content itself. 209 EncapsulatedContentInfo ::= SEQUENCE { 210 eContentType ContentType, 211 eContent [0] EXPLICIT OCTET STRING OPTIONAL } 213 ContentType ::= OBJECT IDENTIFIER 215 3.1.3.1. eContentType 217 The ContentType for a AAO is defined as id-ct-ASAdjancyAttest and has 218 the numerical value of 1.2.840.113549.1.9.16.1.32. 220 id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) 221 rsadsi(113549) pkcs(1) pkcs9(9) 16 } 223 id-ct OBJECT IDENTIFIER ::= { id-smime 1 } 225 id-ct-ASAdjacencyAttest OBJECT IDENTIFIER ::= { id-ct 32 } 227 3.1.3.2. eContent 229 The content of an AAO identifies one or more AS's that the signing AS 230 holder is attesting the existence of a routing adjacency. 232 The AAO contains no routing policy qualifications, nor does it 233 reference any address prefixes that may be announced or received 234 within the context of any routing adjacency. 236 An AAO is defined as: 238 id-ct-ASAdjacencyAttest ::= SEQUENCE { 239 version [0] INTEGER DEFAULT 0, 240 ASIdentifiers ::= SEQUENCE OF ASIdOrRange, 241 localASNum ASId} 243 ASIdOrRange ::= CHOICE { 244 id ASId, 245 range ASRange } 247 ASRange ::= SEQUENCE { 248 min ASId, 249 max ASId } 251 ASId ::= INTEGER 253 3.1.3.2.1. version 255 The version number of the ASAdjacencyAttestation MUST be 0. 257 3.1.3.2.2. ASIdentifiers 259 The ASIdentifiers element is a SEQUENCE containing AS numbers for 260 which the localASnum AS is attesting the existence of a routing 261 adjacency. Any pair of items in the asIdentifiers SEQUENCE MUST NOT 262 overlap. Any contiguous series of AS identifiers MUST be combined 263 into a single range whenever possible. The AS identifiers in the 264 asIdentifiers element MUST be sorted by increasing numeric value. 266 3.1.3.2.2.1. ASIdOrRange 268 The ASIdOrRange type is a CHOICE of either a single integer (ASId) or 269 a single sequence (ASRange). 271 3.1.3.2.2.2. ASRange 273 The ASRange type is a SEQUENCE consisting of a min and a max element, 274 and is used to specify a range of AS identifier values. 276 3.1.3.2.2.2.1. min and max 278 The min and max elements have type ASId. The min element is used to 279 specify the value of the minimum AS identifier in the range, and the 280 max element specifies the value of the maximum AS identifier in the 281 range. 283 3.1.3.2.2.3. ASId 285 The ASId type is an INTEGER. 287 3.1.3.2.3. localASNum 289 The localASNum field contains the AS that is making the attestation 290 of routing adjacency to each of the AS's listed in the ASIdentifiers 291 element. 293 3.1.4. CertificateSet 295 The CertificateSet type is defined in section 10 of [RFC5652] 297 3.1.5. certificates 299 The certificates element MUST be included and MUST contain only the 300 single EE resource certificate needed to validate this AAO. 302 3.1.6. crls 304 The crls element MUST be omitted. 306 3.1.7. signerInfos 308 SignerInfo is defined under CMS as: 310 SignerInfo ::= SEQUENCE { 311 version CMSVersion, 312 sid SignerIdentifier, 313 digestAlgorithm DigestAlgorithmIdentifier, 314 signedAttrs [0] IMPLICIT SignedAttributes OPTIONAL, 315 signatureAlgorithm SignatureAlgorithmIdentifier, 316 signature SignatureValue, 317 unsignedAttrs [1] IMPLICIT UnsignedAttributes OPTIONAL } 319 3.1.7.1. version 321 The version number MUST be 3, corresponding with the choice of 322 SubjectKeyIdentifier for the sid. 324 3.1.7.2. sid 326 The sid is defined as: 328 SignerIdentifier ::= CHOICE { 329 issuerAndSerialNumber IssuerAndSerialNumber, 330 subjectKeyIdentifier [0] SubjectKeyIdentifier } 332 For a AAO, the sid MUST be a SubjectKeyIdentifier. 334 3.1.7.3. digestAlgorithm 336 The digestAlgorithm MUST consist of the OID of a digest algorithm 337 that conforms to the RPKI Algorithms and Key Size Profile 338 specification [ID.sidr-rpki-algs]. 340 3.1.7.4. signedAttrs 342 The signedAttrs is defined as: 344 SignedAttributes ::= SET SIZE (1..MAX) OF Attribute 346 Attribute ::= SEQUENCE { 347 attrType OBJECT IDENTIFIER, 348 attrValues SET OF AttributeValue } 350 AttributeValue ::= ANY 352 The signedAttr element MUST be present and MUST include the content- 353 type and message-digest signed attributes. The signer MAY also 354 include the signing-time signed attribute, the binary-signing-time 355 signed attribute, or both signed attributes. Other signed attributes 356 that are deemed appropriate by the signer MAY also be included. The 357 intent is to allow additional signed attributes to be included if a 358 future need is identified. This does not cause an interoperability 359 concern because unrecognized signed attributes are ignored by the 360 relying party. 362 The signedAttr MUST include only a single instance of any particular 363 attribute. Additionally, even though the syntax allows for a SET OF 364 AttributeValue, in a AAO the attrValues must consist of only a single 365 AttributeValue 367 3.1.7.4.1. ContentType Attribute 369 The ContentType attribute MUST be present. The attrType OID for the 370 ContentType attribute is 1.2.840.113549.1.9.3. 372 The attrValues for the ContentType attribute in a AAO MUST be 373 1.2.840.113549.1.9.16.1.24 (matching the eContentType in the 374 EncapsulatedContentInfo). 376 3.1.7.4.2. MessageDigest Attribute 378 The MessageDigest attribute MUST be present. The attrType OID for 379 the MessageDigest Attribute is 1.2.840.113549.1.9.4. 381 The attrValues for the MessageDigest attribute contains the output of 382 the digest algorithm applied to the content being signed, as 383 specified in Section 11.1 of [RFC5652]. 385 3.1.7.4.3. SigningTime Attribute 387 The SigningTime attribute MAY be present. If it is present it MUST 388 be ignored by the relying party. The presence of absence of the 389 SigningTime attribute in no way affects the validation of the AAO (as 390 specified in Section 4). The attrType OID for the SigningTime 391 attribute is 1.2.840.113549.1.9.5. 393 The attrValues for the SigningTime attribute is defined as: 395 SigningTime ::= Time 397 Time ::= CHOICE { 398 utcTime UTCTime, 399 generalizedTime GeneralizedTime } 401 The Time element specifies the time, based on the local system clock, 402 at which the digital signature was applied to the content. 404 3.1.7.4.4. BinarySigningTimeAttribute 406 The BinarySigningTime attribute MAY be present. If it is present it 407 MUST be ignored by the relying party. The presence of absence of the 408 BinarySigningTime attribute in no way affects the validation of the 409 AAO (as specified in Section 3). The attrType OID for the 410 SigningTime attribute is 1.2.840.113549.1.9.16.2.46. 412 The attrValues for the SigningTime attribute is defined as: 414 BinarySigningTime ::= BinaryTime 416 BinaryTime ::= INTEGER (0..MAX) 418 The BinaryTime element specifies the time, based on the local system 419 clock, at which the digital signature was applied to the content. 421 3.1.7.5. signatureAlgorithm 423 The signatureAlgorithm MUST consist of the OID of a signature 424 algorithm that conforms RPKI Algorithms and Key Size Profile 425 specification [ID.sidr-rpki-algs]. 427 3.1.7.6. signature 429 The signature value is defined as: 431 SignatureValue ::= OCTET STRING 433 The signature characteristics are defined by the digest and signature 434 algorithms. 436 3.1.7.7. unsignedAttrs 438 unsignedAttrs MUST be omitted. 440 4. AAO Validation 442 Before a relying party can use an AAO, the relying party must first 443 use the RPKI to validate the AAO by performing the following steps. 445 1. Verify that the AAO syntax complies with this specification. In 446 particular, verify the following: 448 a. The contentType of the CMS object is SignedData (OID 449 1.2.840.113549.1.7.2). 451 b. The version of the SignedData object is 3. 453 c. The certificates field in the SignedData object is present 454 and contains an EE certificate whose Subject Key Identifier 455 (SKI) matches the sid field of the SignerInfo object. 457 d. The crls field in the SignedData object is omitted. 459 e. The eContentType in the EncapsulatedContentInfo is id-ct- 460 ADAdjacencyAttest (OID 1.2.840.113549.1.9.16.1.32) 462 f. The version of the id-ct-ASAdjacencyAttest is 0. 464 g. The version of the SignerInfo is 3. 466 h. The signedAttrs field in the SignerInfo object is present and 467 contains both the ContentType attribute (OID 468 1.2.840.113549.1.9.3) and the MessageDigest attribute (OID 469 1.2.840.113549.1.9.4). 471 i. The unsignedAttrs field in the SignerInfo object is omitted. 473 j. The digestAlgorithm in the SignedData and SignerInfo objects 474 as well as the signatureAlgorithm in the SignerInfo object 475 conform to the RPKI Algorithms and Key Size Profile 476 specification [ID.sidr-rpki-algs]. 478 2. The public key in the EE certificate (contained within the AAO) 479 can be used to successfully verify the signature on the AAO. 481 3. The EE certificate has an Autonomous System Identifier Delegation 482 Extension [RFC3779] and that the Autonomous System Identifier in 483 that extension exactly matches the Autonomous System Identifier 484 in the localASNum element of the AAO. 486 4. The EE certificate is a valid end-entity certificate in the 487 Resource PKI as specified by [ID.ietf-sidr-res-certs]. (in 488 particular, there exists a valid certification path from a trust 489 anchor to the EE certificate.) 491 5. Security Considerations 493 There is no assumption of confidentiality for the data in a AAO; it 494 is anticipated that AAOs will be stored in public repositories that 495 are accessible to all ISPs, and potentially to all Internet users. 496 There is no explicit authentication associated with a AAO, since the 497 RPKI that is used for AAO validation provides authorization but not 498 authentication. Although the AAO is a signed, application layer 499 object, there is no intent to convey non-repudiation via a AAO. 501 The purpose of a AAO is to convey a unilateral statement of routing 502 capability that an AS has the capability to announce route objects 503 via a routing adjacency with another AS and has the capability to 504 listen for route objects that are passed to it over a routing 505 adjacency. This should not be interpreted as an authority, nor is a 506 relying party justified in assuming that such a routing adjacency 507 exists, nor that any valid routing announcements that are passed 508 across this routing adjacency. 510 A relying party may be able to place greater confidence in the 511 inferred existence of a routing adjacency in the case where both AS 512 holders have issued current AAO objects that nominate each other as 513 an adjacent AS. 515 The AAO object does not convey any information relating to route 516 policies that may be applied to the adjacency by either party to a 517 route adjacency, nor what prefixes may be advertised across that 518 adjacency, nor any attributes that may be associated with such 519 advertisements. 521 6. IANA Considerations 523 [Note to IANA, to be removed prior to publication: there are no IANA 524 considerations stated in this version of the document.] 526 7. Acknowledgements 528 The authors would like to acknowledge the work of Matt Lepinski, 529 Stephen Kent and Derrick Kong, whose work on the Route Origin 530 Attestation Profile was used as the starting point for this document. 532 8. References 534 8.1. Normative References 536 [ID.ietf-sidr-arch] 537 Lepinski, M. and S. Kent, "An Infrastructure to Support 538 Secure Internet Routing", draft-ietf-sidr-arch (work in 539 progress), March 2009. 541 [ID.ietf-sidr-res-certs] 542 Huston, G., Michaleson, G., and R. Loomans, "A Profile for 543 X.509 PKIX Resource Certificates", Internet 544 Draft draft-ietf-sidr-res-certs, February 2009. 546 [ID.sidr-rpki-algs] 547 Huston, G., "A Profile for Algorithms and Key Sizes for 548 use in the Resource Public Key Infrastructure", Work in 549 progress: Internet 550 Drafts draft-ietf-sidr-rpki-algs-00.txt, August 2009. 552 [RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP 553 Addresses and AS Identifiers", RFC 3779, June 2004. 555 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 556 Housley, R., and W. Polk, "Internet X.509 Public Key 557 Infrastructure Certificate and Certificate Revocation List 558 (CRL) Profile", RFC 5280, May 2008. 560 [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", 561 RFC 5652, September 2009. 563 8.2. Informative References 565 [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway 566 Protocol 4 (BGP-4)", RFC 4271, January 2006. 568 Authors' Addresses 570 Geoff Huston 572 Email: gih@apnic.net 573 URI: http://www.apnic.net 575 George Michaelson 577 Email: ggm@apnic.net 578 URI: http://www.apnic.net