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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Host Identity Protocol Heer 3 Internet-Draft Albstadt-Sigmaringen University 4 Obsoletes: 6253 (if approved) Varjonen 5 Updates: 7401 (if approved) University of Helsinki 6 Intended status: Standards Track November 3, 2015 7 Expires: May 6, 2016 9 Host Identity Protocol Certificates 10 draft-ietf-hip-rfc6253-bis-05 12 Abstract 14 The Certificate (CERT) parameter is a container for digital 15 certificates. It is used for carrying these certificates in Host 16 Identity Protocol (HIP) control packets. This document specifies the 17 certificate parameter and the error signaling in case of a failed 18 verification. Additionally, this document specifies the 19 representations of Host Identity Tags in X.509 version 3 (v3). 21 The concrete use cases of certificates, including how certificates 22 are obtained, requested, and which actions are taken upon successful 23 or failed verification, are specific to the scenario in which the 24 certificates are used. Hence, the definition of these scenario- 25 specific aspects is left to the documents that use the CERT 26 parameter. 28 This document extends RFC7401 and obsoletes RFC6253. 30 Status of This Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at http://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on May 6, 2016. 47 Copyright Notice 48 Copyright (c) 2015 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 1. Introduction 63 Digital certificates bind pieces of information to a public key by 64 means of a digital signature, and thus, enable the holder of a 65 private key to generate cryptographically verifiable statements. The 66 Host Identity Protocol (HIP) [RFC7401] defines a new cryptographic 67 namespace based on asymmetric cryptography. The identity of each 68 host is derived from a public key, allowing hosts to digitally sign 69 data and issue certificates with their private key. This document 70 specifies the CERT parameter, which is used to transmit digital 71 certificates in HIP. It fills the placeholder specified in 72 Section 5.2 of [RFC7401], and thus, extends [RFC7401]. 74 1.1. Requirements Language 76 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 77 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 78 "OPTIONAL" in this document are to be interpreted as described in RFC 79 2119 [RFC2119]. 81 2. CERT Parameter 83 The CERT parameter is a container for certain types of digital 84 certificates. It does not specify any certificate semantics. 85 However, it defines supplementary parameters that help HIP hosts to 86 transmit semantically grouped CERT parameters in a more systematic 87 way. The specific use of the CERT parameter for different use cases 88 is intentionally not discussed in this document. Hence, the use of 89 the CERT parameter will be defined in the documents that use the CERT 90 parameter. 92 The CERT parameter is covered and protected, when present, by the HIP 93 SIGNATURE field and is a non-critical parameter. 95 The CERT parameter can be used in all HIP packets. However, using it 96 in the first Initiator (I1) packet is NOT RECOMMENDED because it can 97 increase the processing times of I1s, which can be problematic when 98 processing storms of I1s. Each HIP control packet MAY contain 99 multiple CERT parameters. These parameters MAY be related or 100 unrelated. Related certificates are managed in Cert groups. A Cert 101 group specifies a group of related CERT parameters that SHOULD be 102 interpreted in a certain order (e.g., for expressing certificate 103 chains). For grouping CERT parameters, the Cert group and the Cert 104 count field MUST be set. Ungrouped certificates exhibit a unique 105 Cert group field and set the Cert count to 1. CERT parameters with 106 the same Cert group number in the group field indicate a logical 107 grouping. The Cert count field indicates the number of CERT 108 parameters in the group. 110 CERT parameters that belong to the same Cert group MAY be contained 111 in multiple sequential HIP control packets. This is indicated by a 112 higher Cert count than the amount of CERT parameters with matching 113 Cert group fields in a HIP control packet. The CERT parameters MUST 114 be placed in ascending order, within a HIP control packet, according 115 to their Cert group field. Cert groups MAY only span multiple 116 packets if the Cert group does not fit the packet. A HIP packet MUST 117 NOT contain more than one incomplete Cert group that continues in the 118 next HIP control packet. 120 The Cert ID acts as a sequence number to identify the certificates in 121 a Cert group. The numbers in the Cert ID field MUST start from 1 up 122 to Cert count. 124 The Cert Group and Cert ID namespaces are managed locally by each 125 host that sends CERT parameters in HIP control packets. 127 0 1 2 3 128 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | Type | Length | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | Cert group | Cert count | Cert ID | Cert type | 133 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 134 | Certificate / 135 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 136 / | Padding | 137 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 139 Type 768 140 Length Length in octets, excluding Type, Length, and Padding 141 Cert group Group ID grouping multiple related CERT parameters 142 Cert count Total count of certificates that are sent, possibly 143 in several consecutive HIP control packets. 144 Cert ID The sequence number for this certificate 145 Cert Type Indicates the type of the certificate 146 Padding Any Padding, if necessary, to make the TLV a multiple 147 of 8 bytes. 149 The certificates MUST use the algorithms defined in [RFC7401] as the 150 signature and hash algorithms. 152 The following certificate types are defined: 154 +--------------------------------+-------------+ 155 | Cert format | Type number | 156 +--------------------------------+-------------+ 157 | Reserved | 0 | 158 | X.509 v3 | 1 | 159 | Hash and URL of X.509 v3 | 2 | 160 | LDAP URL of X.509 v3 | 3 | 161 | Distinguished Name of X.509 v3 | 4 | 162 +--------------------------------+-------------+ 164 The next sections outline the use of Host Identity Tags (HITs) in 165 X.509 v3. X.509 v3 certificates and the handling procedures are 166 defined in [RFC5280]. The wire format for X.509 v3 is the 167 Distinguished Encoding Rules format as defined in [X.690]. 169 Hash and Uniform Resource Locator (URL) encodings (3 and 4) are used 170 as defined in Section 3.6 of [RFC7296]. Using hash and URL encodings 171 results in smaller HIP control packets than by including the 172 certificate(s), but requires the receiver to resolve the URL or check 173 a local cache against the hash. 175 Lightweight Directory Access Protocol (LDAP) URL encodings (5 and 6) 176 are used as defined in [RFC4516]. Using LDAP URL encoding results in 177 smaller HIP control packets but requires the receiver to retrieve the 178 certificate or check a local cache against the URL. 180 Distinguished Name (DN) encodings (7 and 8) are represented by the 181 string representation of the certificate's subject DN as defined in 182 [RFC4514]. Using the DN encoding results in smaller HIP control 183 packets, but requires the receiver to retrieve the certificate or 184 check a local cache against the DN. 186 3. X.509 v3 Certificate Object and Host Identities 188 If needed, HITs can represent an issuer, a subject, or both in X.509 189 v3. HITs are represented as IPv6 addresses as defined in [RFC7343]. 191 When the Host Identifier (HI) is used to sign the certificate, the 192 respective HIT SHOULD be placed into the Issuer Alternative Name 193 (IAN) extension using the GeneralName form iPAddress as defined in 194 [RFC5280]. When the certificate is issued for a HIP host, identified 195 by a HIT and HI, the respective HIT SHOULD be placed into the Subject 196 Alternative Name (SAN) extension using the GeneralName form 197 iPAddress, and the full HI is presented as the subject's public key 198 info as defined in [RFC5280]. 200 The following examples illustrate how HITs are presented as issuer 201 and subject in the X.509 v3 extension alternative names. 203 Format of X509v3 extensions: 204 X509v3 Issuer Alternative Name: 205 IP Address:hit-of-issuer 206 X509v3 Subject Alternative Name: 207 IP Address:hit-of-subject 209 Example X509v3 extensions: 210 X509v3 Issuer Alternative Name: 211 IP Address:2001:24:6cf:fae7:bb79:bf78:7d64:c056 212 X509v3 Subject Alternative Name: 213 IP Address:2001:2c:5a14:26de:a07c:385b:de35:60e3 215 Appendix A shows a full example X.509 v3 certificate with HIP 216 content. 218 As another example, consider a managed Public Key Infrastructure 219 (PKI) environment in which the peers have certificates that are 220 anchored in (potentially different) managed trust chains. In this 221 scenario, the certificates issued to HIP hosts are signed by 222 intermediate Certification Authorities (CAs) up to a root CA. In 223 this example, the managed PKI environment is neither HIP aware, nor 224 can it be configured to compute HITs and include them in the 225 certificates. 227 When HIP communications are established, the HIP hosts not only need 228 to send their identity certificates (or pointers to their 229 certificates), but also the chain of intermediate CAs (or pointers to 230 the CAs) up to the root CA, or to a CA that is trusted by the remote 231 peer. This chain of certificates SHOULD be sent in a Cert group as 232 specified in Section 2. The HIP peers validate each other's 233 certificates and compute peer HITs based on the certificate public 234 keys. 236 4. Revocation of Certificates 237 Revocation of X.509 v3 certificates is handled as defined in 238 Section 5 of [RFC5280]. 240 5. Error Signaling 242 If the Initiator does not send the certificate that the Responder 243 requires, the Responder may take actions (e.g. reject the 244 connection). The Responder MAY signal this to the Initiator by 245 sending a HIP NOTIFY message with NOTIFICATION parameter error type 246 CREDENTIALS_REQUIRED. 248 If the verification of a certificate fails, a verifier MAY signal 249 this to the provider of the certificate by sending a HIP NOTIFY 250 message with NOTIFICATION parameter error type INVALID_CERTIFICATE. 252 NOTIFICATION PARAMETER - ERROR TYPES Value 253 ------------------------------------ ----- 255 CREDENTIALS_REQUIRED 48 257 The Responder is unwilling to set up an association, 258 as the Initiator did not send the needed credentials. 260 INVALID_CERTIFICATE 50 262 Sent in response to a failed verification of a certificate. 263 Notification Data MAY contain n groups of 2 octets (n calculated 264 from the NOTIFICATION parameter length), in order Cert group and 265 Cert ID of the CERT parameter that caused the failure. 267 6. IANA Considerations 269 As this document replaces [RFC6253], references to [RFC6253] in IANA 270 registries have to be replaced by references to this document. This 271 document changes Certificate type registry in Section 2. 273 7. Security Considerations 275 Certificate grouping allows the certificates to be sent in multiple 276 consecutive packets. This might allow similar attacks, as IP-layer 277 fragmentation allows, for example, the sending of fragments in the 278 wrong order and skipping some fragments to delay or stall packet 279 processing by the victim in order to use resources (e.g., CPU or 280 memory). Hence, hosts SHOULD implement mechanisms to discard 281 certificate groups with outstanding certificates if state space is 282 scarce. 284 Checking of the URL and LDAP entries might allow denial-of-service 285 (DoS) attacks, where the target host may be subjected to bogus work. 287 Security considerations for X.509 v3 in [RFC5280]. 289 8. Acknowledgements 291 The authors would like to thank A. Keranen, D. Mattes, M. Komu and T. 292 Henderson for the fruitful conversations on the subject. D. Mattes 293 most notably contributed the non-HIP aware use case in Section 3. 295 9. References 297 9.1. Normative References 299 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 300 Requirement Levels", BCP 14, RFC 2119, March 1997. 302 [RFC4514] Zeilenga, K., "Lightweight Directory Access Protocol 303 (LDAP): String Representation of Distinguished Names", RFC 304 4514, June 2006. 306 [RFC4516] Smith, M. and T. Howes, "Lightweight Directory Access 307 Protocol (LDAP): Uniform Resource Locator", RFC 4516, June 308 2006. 310 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 311 Housley, R., and W. Polk, "Internet X.509 Public Key 312 Infrastructure Certificate and Certificate Revocation List 313 (CRL) Profile", RFC 5280, May 2008. 315 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 316 Kivinen, "Internet Key Exchange Protocol Version 2 317 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 318 2014, . 320 [RFC7343] Laganier, J. and F. Dupont, "An IPv6 Prefix for Overlay 321 Routable Cryptographic Hash Identifiers Version 2 322 (ORCHIDv2)", RFC 7343, DOI 10.17487/RFC7343, September 323 2014, . 325 [RFC7401] Moskowitz, R., Heer, T., Jokela, P., and T. Henderson, 326 "Host Identity Protocol Version 2 (HIPv2)", RFC 7401, 327 April 2015. 329 [X.690] ITU-T, , "Recommendation X.690 (2002) | ISO/IEC 330 8825-1:2002, Information Technology - ASN.1 encoding 331 rules: Specification of Basic Encoding Rules (BER), 332 Canonical Encoding Rules (CER) and Distinguished Encoding 333 Rules (DER)", July 2002. 335 9.2. Informative References 337 [RFC6253] Heer, T. and S. Varjonen, "Host Identity Protocol 338 Certificates", RFC 6253, DOI 10.17487/RFC6253, May 2011, 339 . 341 Appendix A. X.509 v3 certificate example 343 This section shows a X.509 v3 certificate with encoded HITs. 345 Certificate: 346 Data: 347 Version: 3 (0x2) 348 Serial Number: 0 (0x0) 349 Signature Algorithm: sha1WithRSAEncryption 350 Issuer: CN=Example issuing host, DC=example, DC=com 351 Validity 352 Not Before: Mar 11 09:01:39 2011 GMT 353 Not After : Mar 21 09:01:39 2011 GMT 354 Subject: CN=Example subject host, DC=example, DC=com 355 Subject Public Key Info: 356 Public Key Algorithm: rsaEncryption 357 RSA Public Key: (1024 bit) 358 Modulus (1024 bit): 359 00:c0:db:38:50:8e:63:ed:96:ea:c6:c4:ec:a3:36: 360 62:e2:28:e9:74:9c:f5:2f:cb:58:0e:52:54:60:b5: 361 fa:98:87:0d:22:ab:d8:6a:61:74:a9:ee:0b:ae:cd: 362 18:6f:05:ab:69:66:42:46:00:a2:c0:0c:3a:28:67: 363 09:cc:52:27:da:79:3e:67:d7:d8:d0:7c:f1:a1:26: 364 fa:38:8f:73:f5:b0:20:c6:f2:0b:7d:77:43:aa:c7: 365 98:91:7e:1e:04:31:0d:ca:94:55:20:c4:4f:ba:b1: 366 df:d4:61:9d:dd:b9:b5:47:94:6c:06:91:69:30:42: 367 9c:0a:8b:e3:00:ce:49:ab:e3 368 Exponent: 65537 (0x10001) 369 X509v3 extensions: 370 X509v3 Issuer Alternative Name: 371 IP Address:2001:23:8d83:41c5:dc9f:38ed:e742:7281 372 X509v3 Subject Alternative Name: 373 IP Address:2001:2c:6e02:d3e0:9b90:8417:673e:99db 374 Signature Algorithm: sha1WithRSAEncryption 375 83:68:b4:38:63:a6:ae:57:68:e2:4d:73:5d:8f:11:e4:ba:30: 376 a0:19:ca:86:22:e9:6b:e9:36:96:af:95:bd:e8:02:b9:72:2f: 377 30:a2:62:ac:b2:fa:3d:25:c5:24:fd:8d:32:aa:01:4f:a5:8a: 378 f5:06:52:56:0a:86:55:39:2b:ee:7a:7b:46:14:d7:5d:15:82: 379 4d:74:06:ca:b7:8c:54:c1:6b:33:7f:77:82:d8:95:e1:05:ca: 381 e2:0d:22:1d:86:fc:1c:c4:a4:cf:c6:bc:ab:ec:b8:2a:1e:4b: 382 04:7e:49:9c:8f:9d:98:58:9c:63:c5:97:b5:41:94:f7:ef:93: 383 57:29 385 Appendix B. Change log 387 Contents of draft-ietf-hip-rfc6253-bis-00: 389 o RFC6253 was submitted as draft-RFC. 391 Changes from version 01 to 02: 393 o Updated the references. 395 Changes from version 02 to 03: 397 o Fixed the nits raised by the working group. 399 Changes from version 03 to 04: 401 o Added "obsoletes RFC 6253". 403 Changes from version 04 to 05: 405 o Updates to contact details. 407 o Correct updates and obsoletes headers. 409 o Removed the pre5378 disclaimer. 411 o Updated references. 413 o Removed the SPKI references from the document. 415 Authors' Addresses 417 Tobias Heer 418 Albstadt-Sigmaringen University 419 Poststr. 6 420 72458 Albstadt 421 Germany 423 Email: heer@hs-albsig.de 424 Samu Varjonen 425 University of Helsinki 426 Gustaf Haellstroemin katu 2b 427 Helsinki 428 Finland 430 Email: samu.varjonen@helsinki.fi