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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 Hirschmann Automation and Control 4 Intended status: Standards Track Varjonen 5 Expires: March 25, 2016 University of Helsinki 6 September 22, 2015 8 Host Identity Protocol Certificates 9 draft-ietf-hip-rfc6253-bis-04 11 Abstract 13 The Certificate (CERT) parameter is a container for digital 14 certificates. It is used for carrying these certificates in Host 15 Identity Protocol (HIP) control packets. This document specifies the 16 certificate parameter and the error signaling in case of a failed 17 verification. Additionally, this document specifies the 18 representations of Host Identity Tags in X.509 version 3 (v3) and 19 Simple Public Key Infrastructure (SPKI) certificates. 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 March 25, 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 This document may contain material from IETF Documents or IETF 62 Contributions published or made publicly available before November 63 10, 2008. The person(s) controlling the copyright in some of this 64 material may not have granted the IETF Trust the right to allow 65 modifications of such material outside the IETF Standards Process. 66 Without obtaining an adequate license from the person(s) controlling 67 the copyright in such materials, this document may not be modified 68 outside the IETF Standards Process, and derivative works of it may 69 not be created outside the IETF Standards Process, except to format 70 it for publication as an RFC or to translate it into languages other 71 than English. 73 1. Introduction 75 Digital certificates bind pieces of information to a public key by 76 means of a digital signature, and thus, enable the holder of a 77 private key to generate cryptographically verifiable statements. The 78 Host Identity Protocol (HIP) [RFC7401] defines a new cryptographic 79 namespace based on asymmetric cryptography. The identity of each 80 host is derived from a public key, allowing hosts to digitally sign 81 data and issue certificates with their private key. This document 82 specifies the CERT parameter, which is used to transmit digital 83 certificates in HIP. It fills the placeholder specified in 84 Section 5.2 of [RFC7401], and thus, extends [RFC7401]. 86 1.1. Requirements Language 88 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 89 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 90 "OPTIONAL" in this document are to be interpreted as described in RFC 91 2119 [RFC2119]. 93 2. CERT Parameter 94 The CERT parameter is a container for certain types of digital 95 certificates. It does not specify any certificate semantics. 96 However, it defines supplementary parameters that help HIP hosts to 97 transmit semantically grouped CERT parameters in a more systematic 98 way. The specific use of the CERT parameter for different use cases 99 is intentionally not discussed in this document. Hence, the use of 100 the CERT parameter will be defined in the documents that use the CERT 101 parameter. 103 The CERT parameter is covered and protected, when present, by the HIP 104 SIGNATURE field and is a non-critical parameter. 106 The CERT parameter can be used in all HIP packets. However, using it 107 in the first Initiator (I1) packet is NOT RECOMMENDED because it can 108 increase the processing times of I1s, which can be problematic when 109 processing storms of I1s. Each HIP control packet MAY contain 110 multiple CERT parameters. These parameters MAY be related or 111 unrelated. Related certificates are managed in Cert groups. A Cert 112 group specifies a group of related CERT parameters that SHOULD be 113 interpreted in a certain order (e.g., for expressing certificate 114 chains). For grouping CERT parameters, the Cert group and the Cert 115 count field MUST be set. Ungrouped certificates exhibit a unique 116 Cert group field and set the Cert count to 1. CERT parameters with 117 the same Cert group number in the group field indicate a logical 118 grouping. The Cert count field indicates the number of CERT 119 parameters in the group. 121 CERT parameters that belong to the same Cert group MAY be contained 122 in multiple sequential HIP control packets. This is indicated by a 123 higher Cert count than the amount of CERT parameters with matching 124 Cert group fields in a HIP control packet. The CERT parameters MUST 125 be placed in ascending order, within a HIP control packet, according 126 to their Cert group field. Cert groups MAY only span multiple 127 packets if the Cert group does not fit the packet. A HIP packet MUST 128 NOT contain more than one incomplete Cert group that continues in the 129 next HIP control packet. 131 The Cert ID acts as a sequence number to identify the certificates in 132 a Cert group. The numbers in the Cert ID field MUST start from 1 up 133 to Cert count. 135 The Cert Group and Cert ID namespaces are managed locally by each 136 host that sends CERT parameters in HIP control packets. 138 0 1 2 3 139 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 1 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 | Type | Length | 142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 143 | Cert group | Cert count | Cert ID | Cert type | 144 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 145 | Certificate / 146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 147 / | Padding | 148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 150 Type 768 151 Length Length in octets, excluding Type, Length, and Padding 152 Cert group Group ID grouping multiple related CERT parameters 153 Cert count Total count of certificates that are sent, possibly 154 in several consecutive HIP control packets. 155 Cert ID The sequence number for this certificate 156 Cert Type Indicates the type of the certificate 157 Padding Any Padding, if necessary, to make the TLV a multiple 158 of 8 bytes. 160 The certificates MUST use the algorithms defined in [RFC7401] as the 161 signature and hash algorithms. 163 The following certificate types are defined: 165 +--------------------------------+-------------+ 166 | Cert format | Type number | 167 +--------------------------------+-------------+ 168 | Reserved | 0 | 169 | X.509 v3 | 1 | 170 | SPKI | 2 | 171 | Hash and URL of X.509 v3 | 3 | 172 | Hash and URL of SPKI | 4 | 173 | LDAP URL of X.509 v3 | 5 | 174 | LDAP URL of SPKI | 6 | 175 | Distinguished Name of X.509 v3 | 7 | 176 | Distinguished Name of SPKI | 8 | 177 +--------------------------------+-------------+ 179 The next sections outline the use of Host Identity Tags (HITs) in 180 X.509 v3 and in Simple Public Key Infrastructure (SPKI) certificates. 181 X.509 v3 certificates and the handling procedures are defined in 182 [RFC5280]. The wire format for X.509 v3 is the Distinguished 183 Encoding Rules format as defined in [X.690]. The SPKI, the handling 184 procedures, and the formats are defined in [RFC2693]. 186 Hash and Uniform Resource Locator (URL) encodings (3 and 4) are used 187 as defined in Section 3.6 of [RFC5996]. Using hash and URL encodings 188 results in smaller HIP control packets than by including the 189 certificate(s), but requires the receiver to resolve the URL or check 190 a local cache against the hash. 192 Lightweight Directory Access Protocol (LDAP) URL encodings (5 and 6) 193 are used as defined in [RFC4516]. Using LDAP URL encoding results in 194 smaller HIP control packets but requires the receiver to retrieve the 195 certificate or check a local cache against the URL. 197 Distinguished Name (DN) encodings (7 and 8) are represented by the 198 string representation of the certificate's subject DN as defined in 199 [RFC4514]. Using the DN encoding results in smaller HIP control 200 packets, but requires the receiver to retrieve the certificate or 201 check a local cache against the DN. 203 3. X.509 v3 Certificate Object and Host Identities 205 If needed, HITs can represent an issuer, a subject, or both in X.509 206 v3. HITs are represented as IPv6 addresses as defined in [RFC7343]. 207 When the Host Identifier (HI) is used to sign the certificate, the 208 respective HIT SHOULD be placed into the Issuer Alternative Name 209 (IAN) extension using the GeneralName form iPAddress as defined in 210 [RFC5280]. When the certificate is issued for a HIP host, identified 211 by a HIT and HI, the respective HIT SHOULD be placed into the Subject 212 Alternative Name (SAN) extension using the GeneralName form 213 iPAddress, and the full HI is presented as the subject's public key 214 info as defined in [RFC5280]. 216 The following examples illustrate how HITs are presented as issuer 217 and subject in the X.509 v3 extension alternative names. 219 Format of X509v3 extensions: 220 X509v3 Issuer Alternative Name: 221 IP Address:hit-of-issuer 222 X509v3 Subject Alternative Name: 223 IP Address:hit-of-subject 225 Example X509v3 extensions: 226 X509v3 Issuer Alternative Name: 227 IP Address:2001:24:6cf:fae7:bb79:bf78:7d64:c056 228 X509v3 Subject Alternative Name: 229 IP Address:2001:2c:5a14:26de:a07c:385b:de35:60e3 231 Appendix B shows a full example X.509 v3 certificate with HIP 232 content. 234 As another example, consider a managed Public Key Infrastructure 235 (PKI) environment in which the peers have certificates that are 236 anchored in (potentially different) managed trust chains. In this 237 scenario, the certificates issued to HIP hosts are signed by 238 intermediate Certification Authorities (CAs) up to a root CA. In 239 this example, the managed PKI environment is neither HIP aware, nor 240 can it be configured to compute HITs and include them in the 241 certificates. 243 When HIP communications are established, the HIP hosts not only need 244 to send their identity certificates (or pointers to their 245 certificates), but also the chain of intermediate CAs (or pointers to 246 the CAs) up to the root CA, or to a CA that is trusted by the remote 247 peer. This chain of certificates SHOULD be sent in a Cert group as 248 specified in Section 2. The HIP peers validate each other's 249 certificates and compute peer HITs based on the certificate public 250 keys. 252 4. SPKI Cert Object and Host Identities 254 When using SPKI certificates to transmit information related to HIP 255 hosts, HITs need to be enclosed within the certificates. HITs can 256 represent an issuer, a subject, or both. In the following, we define 257 the representation of those identifiers for SPKI given as 258 S-expressions. Note that the S-expressions are only the human- 259 readable representation of SPKI certificates. Full HIs are presented 260 in the public key sequences of SPKI certificates. 262 As an example, the Host Identity Tag of a host is expressed as 263 follows: 265 Format: (hash hit hit-of-host) 266 Example: (hash hit 2001:23:724d:f3c0:6ff0:33c2:15d8:5f50) 268 Appendix A shows a full example of a SPKI certificate with HIP 269 content. 271 5. Revocation of Certificates 273 Revocation of X.509 v3 certificates is handled as defined in 274 Section 5 of [RFC5280]. Revocation of SPKI certificates is handled 275 as defined in Section 5 of [RFC2693]. 277 6. Error Signaling 279 If the Initiator does not send the certificate that the Responder 280 requires, the Responder may take actions (e.g. reject the 281 connection). The Responder MAY signal this to the Initiator by 282 sending a HIP NOTIFY message with NOTIFICATION parameter error type 283 CREDENTIALS_REQUIRED. 285 If the verification of a certificate fails, a verifier MAY signal 286 this to the provider of the certificate by sending a HIP NOTIFY 287 message with NOTIFICATION parameter error type INVALID_CERTIFICATE. 289 NOTIFICATION PARAMETER - ERROR TYPES Value 290 ------------------------------------ ----- 292 CREDENTIALS_REQUIRED 48 294 The Responder is unwilling to set up an association, 295 as the Initiator did not send the needed credentials. 297 INVALID_CERTIFICATE 50 299 Sent in response to a failed verification of a certificate. 300 Notification Data MAY contain n groups of 2 octets (n calculated 301 from the NOTIFICATION parameter length), in order Cert group and 302 Cert ID of the CERT parameter that caused the failure. 304 7. IANA Considerations 306 As this document replaces [RFC6253], references to [RFC6253] in IANA 307 registries have to be replaced by references to this document. 309 8. Security Considerations 311 Certificate grouping allows the certificates to be sent in multiple 312 consecutive packets. This might allow similar attacks, as IP-layer 313 fragmentation allows, for example, the sending of fragments in the 314 wrong order and skipping some fragments to delay or stall packet 315 processing by the victim in order to use resources (e.g., CPU or 316 memory). Hence, hosts SHOULD implement mechanisms to discard 317 certificate groups with outstanding certificates if state space is 318 scarce. 320 Checking of the URL and LDAP entries might allow denial-of-service 321 (DoS) attacks, where the target host may be subjected to bogus work. 323 Security considerations for SPKI certificates are discussed in 324 [RFC2693] and for X.509 v3 in [RFC5280]. 326 9. Acknowledgements 328 The authors would like to thank A. Keranen, D. Mattes, M. Komu and T. 329 Henderson for the fruitful conversations on the subject. D. Mattes 330 most notably contributed the non-HIP aware use case in Section 3. 332 10. Normative References 334 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 335 Requirement Levels", BCP 14, RFC 2119, March 1997. 337 [RFC2693] Ellison, C., Frantz, B., Lampson, B., Rivest, R., Thomas, 338 B., and T. Ylonen, "SPKI Certificate Theory", RFC 2693, 339 September 1999. 341 [RFC4514] Zeilenga, K., "Lightweight Directory Access Protocol 342 (LDAP): String Representation of Distinguished Names", RFC 343 4514, June 2006. 345 [RFC4516] Smith, M. and T. Howes, "Lightweight Directory Access 346 Protocol (LDAP): Uniform Resource Locator", RFC 4516, June 347 2006. 349 [RFC4843] Nikander, P., Laganier, J., and F. Dupont, "An IPv6 Prefix 350 for Overlay Routable Cryptographic Hash Identifiers 351 (ORCHID)", RFC 4843, April 2007. 353 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 354 Housley, R., and W. Polk, "Internet X.509 Public Key 355 Infrastructure Certificate and Certificate Revocation List 356 (CRL) Profile", RFC 5280, May 2008. 358 [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, 359 "Internet Key Exchange Protocol Version 2 (IKEv2)", RFC 360 5996, September 2010. 362 [RFC6253] Heer, T. and S. Varjonen, "Host Identity Protocol 363 Certificates", RFC 6253, DOI 10.17487/RFC6253, May 2011, 364 . 366 [RFC7343] Laganier, J. and F. Dupont, "An IPv6 Prefix for Overlay 367 Routable Cryptographic Hash Identifiers Version 2 368 (ORCHIDv2)", RFC 7343, DOI 10.17487/RFC7343, September 369 2014, . 371 [RFC7401] Moskowitz, R., Heer, T., Jokela, P., and T. Henderson, 372 "Host Identity Protocol Version 2 (HIPv2)", RFC 7401, 373 April 2015. 375 [X.690] ITU-T, , "Recommendation X.690 (2002) | ISO/IEC 376 8825-1:2002, Information Technology - ASN.1 encoding 377 rules: Specification of Basic Encoding Rules (BER), 378 Canonical Encoding Rules (CER) and Distinguished Encoding 379 Rules (DER)", July 2002. 381 Appendix A. SPKI certificate example 383 This section shows an SPKI certificate with encoded HITs. The 384 example has been indented for readability. 386 (sequence 387 (public_key 388 (rsa-pkcs1-sha1 389 (e #010001#) 390 (n |yDwznOwX0w+zvQbpWoTnfWrUPLKW2NFrpXbsIcH/QBSLb 391 k1RKTZhLasFwvtSHAjqh220W8gRiQAGIqKplyrDEqSrJp 392 OdIsHIQ8BQhJAyILWA1Sa6f5wAnWozDfgdXoKLNdT8ZNB 393 mzluPiw4ozc78p6MHElH75Hm3yHaWxT+s83M=| 394 ) 395 ) 396 ) 397 (cert 398 (issuer 399 (hash hit 2001:25:2453:698a:9aa:253a:dcb5:981e) 400 ) 401 (subject 402 (hash hit 2001:22:ccd6:4715:72a3:2ab1:77e4:4acc) 403 ) 404 (not-before "2011-01-12_13:43:09") 405 (not-after "2011-01-22_13:43:09") 406 ) 407 (signature 408 (hash sha1 |h5fC8HUMATTtK0cjYqIgeN3HCIMA|) 409 |u8NTRutINI/AeeZgN6bngjvjYPtVahvY7MhGfenTpT7MCgBy 410 NoZglqH5Cy2vH6LrQFYWx0MjWoYwHKimEuBKCNd4TK6hrCyAI 411 CIDJAZ70TyKXgONwDNWPOmcc3lFmsih8ezkoBseFWHqRGISIm 412 MLdeaMciP4lVfxPY2AQKdMrBc=| 413 ) 414 ) 416 Appendix B. X.509 v3 certificate example 418 This section shows a X.509 v3 certificate with encoded HITs. 420 Certificate: 421 Data: 422 Version: 3 (0x2) 423 Serial Number: 0 (0x0) 424 Signature Algorithm: sha1WithRSAEncryption 425 Issuer: CN=Example issuing host, DC=example, DC=com 426 Validity 427 Not Before: Mar 11 09:01:39 2011 GMT 428 Not After : Mar 21 09:01:39 2011 GMT 430 Subject: CN=Example subject host, DC=example, DC=com 431 Subject Public Key Info: 432 Public Key Algorithm: rsaEncryption 433 RSA Public Key: (1024 bit) 434 Modulus (1024 bit): 435 00:c0:db:38:50:8e:63:ed:96:ea:c6:c4:ec:a3:36: 436 62:e2:28:e9:74:9c:f5:2f:cb:58:0e:52:54:60:b5: 437 fa:98:87:0d:22:ab:d8:6a:61:74:a9:ee:0b:ae:cd: 438 18:6f:05:ab:69:66:42:46:00:a2:c0:0c:3a:28:67: 439 09:cc:52:27:da:79:3e:67:d7:d8:d0:7c:f1:a1:26: 440 fa:38:8f:73:f5:b0:20:c6:f2:0b:7d:77:43:aa:c7: 441 98:91:7e:1e:04:31:0d:ca:94:55:20:c4:4f:ba:b1: 442 df:d4:61:9d:dd:b9:b5:47:94:6c:06:91:69:30:42: 443 9c:0a:8b:e3:00:ce:49:ab:e3 444 Exponent: 65537 (0x10001) 445 X509v3 extensions: 446 X509v3 Issuer Alternative Name: 447 IP Address:2001:23:8d83:41c5:dc9f:38ed:e742:7281 448 X509v3 Subject Alternative Name: 449 IP Address:2001:2c:6e02:d3e0:9b90:8417:673e:99db 450 Signature Algorithm: sha1WithRSAEncryption 451 83:68:b4:38:63:a6:ae:57:68:e2:4d:73:5d:8f:11:e4:ba:30: 452 a0:19:ca:86:22:e9:6b:e9:36:96:af:95:bd:e8:02:b9:72:2f: 453 30:a2:62:ac:b2:fa:3d:25:c5:24:fd:8d:32:aa:01:4f:a5:8a: 454 f5:06:52:56:0a:86:55:39:2b:ee:7a:7b:46:14:d7:5d:15:82: 455 4d:74:06:ca:b7:8c:54:c1:6b:33:7f:77:82:d8:95:e1:05:ca: 456 e2:0d:22:1d:86:fc:1c:c4:a4:cf:c6:bc:ab:ec:b8:2a:1e:4b: 457 04:7e:49:9c:8f:9d:98:58:9c:63:c5:97:b5:41:94:f7:ef:93: 458 57:29 460 Appendix C. Change log 462 Contents of draft-ietf-hip-rfc6253-bis-00: 464 o RFC6253 was submitted as draft-RFC. 466 Changes from version 01 to 02: 468 o Updated the references. 470 Changes from version 02 to 03: 472 o Fixed the nits raised by the working group. 474 Changes from version 03 to 04: 476 o Added "obsoletes RFC 6253". 478 Authors' Addresses 480 Tobias Heer 481 Hirschmann Automation and Control 482 Stuttgarter Strasse 45-51 483 Neckartenzlingen 72654 484 Germany 486 Email: tobias.heer@belden.com 488 Samu Varjonen 489 University of Helsinki 490 Gustaf Haellstroemin katu 2b 491 Helsinki 492 Finland 494 Email: samu.varjonen@helsinki.fi