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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DHC Working Group S. Jiang 3 Internet-Draft Huawei Technologies Co., Ltd 4 Intended status: Standards Track L. Li 5 Expires: April 21, 2017 Y. Cui 6 Tsinghua University 7 T. Jinmei 8 Infoblox Inc. 9 T. Lemon 10 Nominum, Inc. 11 D. Zhang 12 October 18, 2016 14 Secure DHCPv6 15 draft-ietf-dhc-sedhcpv6-16 17 Abstract 19 DHCPv6 includes no deployable security mechanism that can protect 20 end-to-end communication between DHCP clients and servers. This 21 document describes a mechanism for using public key cryptography to 22 provide such security. The mechanism provides encryption in all 23 cases, and can be used for authentication based on pre-sharing of 24 authorized certificates. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on April 21, 2017. 43 Copyright Notice 45 Copyright (c) 2016 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 61 2. Requirements Language and Terminology . . . . . . . . . . . . 3 62 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 63 4. Security Issues of DHCPv6 . . . . . . . . . . . . . . . . . . 4 64 5. Secure DHCPv6 Overview . . . . . . . . . . . . . . . . . . . 5 65 5.1. Solution Overview . . . . . . . . . . . . . . . . . . . . 5 66 5.2. New Components . . . . . . . . . . . . . . . . . . . . . 6 67 5.3. Support for Algorithm Agility . . . . . . . . . . . . . . 7 68 5.4. Caused change to RFC3315 . . . . . . . . . . . . . . . . 7 69 5.5. Applicability . . . . . . . . . . . . . . . . . . . . . . 8 70 6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 8 71 7. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 12 72 8. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . 14 73 9. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 14 74 9.1. Increasing Number Check . . . . . . . . . . . . . . . . . 14 75 10. Extensions for Secure DHCPv6 . . . . . . . . . . . . . . . . 15 76 10.1. New DHCPv6 Options . . . . . . . . . . . . . . . . . . . 15 77 10.1.1. Certificate Option . . . . . . . . . . . . . . . . . 15 78 10.1.2. Signature option . . . . . . . . . . . . . . . . . . 17 79 10.1.3. Increasing-number Option . . . . . . . . . . . . . . 19 80 10.1.4. Encrypted-message Option . . . . . . . . . . . . . . 20 81 10.2. New DHCPv6 Messages . . . . . . . . . . . . . . . . . . 21 82 10.3. Status Codes . . . . . . . . . . . . . . . . . . . . . . 21 83 11. Security Considerations . . . . . . . . . . . . . . . . . . . 22 84 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 85 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 24 86 14. Change log [RFC Editor: Please remove] . . . . . . . . . . . 24 87 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 26 88 15.1. Normative References . . . . . . . . . . . . . . . . . . 26 89 15.2. Informative References . . . . . . . . . . . . . . . . . 28 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 92 1. Introduction 94 The Dynamic Host Configuration Protocol for IPv6 (DHCPv6, [RFC3315]) 95 allows DHCPv6 servers to flexibly provide addressing and other 96 configuration information relating to local network infrastructure to 97 DHCP clients. The protocol provides no deployable security 98 mechanism, and consequently is vulnerable to various attacks. 100 This document provides a brief summary of the security 101 vulnerabilities of the DHCPv6 protocol and then describes a new 102 extension to the protocol that provides two additional types of 103 security: 105 o authentication of the DHCPv6 client and the DHCPv6 server to 106 defend against active attacks, such as spoofing. 108 o encryption between the DHCPv6 client and the DHCPv6 server in 109 order to protect the DHCPv6 communication from pervasive 110 monitoring. 112 The extension specified in this document applies only to end-to-end 113 communication between DHCP servers and clients. Options added by 114 relay agents in Relay-Forward messages, and options other than the 115 client message in Relay-Reply messages sent by DHCP servers, are not 116 protected. Such communications are already protected using the 117 mechanism described in section 21.1 in [RFC3315]. 119 This extension introduces two new DHCPv6 messages: the Encrypted- 120 Query and the Encrypted-Response messages. It defines four new 121 DHCPv6 options: the Certificate, the Signature, the Increasing- 122 number, and the Encrypted-message options. The Certificate, 123 Signature, and Increasing-number options are used for authentication. 124 The Encryption-Query message, Encryption-Response message and 125 Encrypted-message option are used for encryption. 127 2. Requirements Language and Terminology 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 [RFC2119] when they 132 appear in ALL CAPS. When these words are not in ALL CAPS (such as 133 "should" or "Should"), they have their usual English meanings, and 134 are not to be interpreted as [RFC2119] key words. 136 3. Terminology 138 This section defines terminology specific to secure DHCPv6 used in 139 this document. 141 secure DHCPv6 client: A node that initiates a DHCPv6 request on a 142 link to obtain DHCPv6 configuration parameters from 143 one or more DHCPv6 servers using the encryption and 144 optional authentication mechanisms defined in this 145 document. 147 secure DHCPv6 server: A DHCPv6 server that implements the 148 authentication and encryption mechanisms defined in 149 this document, and is configured to use them. 151 4. Security Issues of DHCPv6 153 [RFC3315] defines an authentication mechanism with integrity 154 protection. This mechanism uses a symmetric key that is shared by 155 the client and server for authentication. It does not provide any 156 key distribution mechanism. 158 For this approach, operators can set up a key database for both 159 servers and clients from which the client obtains a key before 160 running DHCPv6. However, manual key distribution runs counter to the 161 goal of minimizing the configuration data needed at each host. 162 Consequently, there are no known deployments of this security 163 mechanism. 165 [RFC3315] provides an additional mechanism for preventing off-network 166 timing attacks using the Reconfigure message: the Reconfigure Key 167 authentication method. However, this method protects only the 168 Reconfigure message. The key is transmitted in plaintext to the 169 client in earlier exchanges and so this method is vulnerable to on- 170 path active attacks. 172 Anonymity Profile for DHCP Clients [RFC7844] explains how to generate 173 DHCPv4 or DHCPv6 requests that minimize the disclosure of identifying 174 information. However, the anonymity profile limits the use of the 175 certain options. It also cannot anticipate new options that may 176 contain private information is defined. In addition, the anonymity 177 profile does not work in cases where the client wants to maintain 178 anonymity from eavesdroppers but must identify itself to the DHCP 179 server with which it intends to communicate. 181 Privacy consideration for DHCPv6 [RFC7824] presents an analysis of 182 the privacy issues associated with the use of DHCPv6 by Internet 183 users. No solutions are presented. 185 Current DHCPv6 messages are still transmitted in cleartext and the 186 privacy information within the DHCPv6 message is not protected from 187 passive attack, such as pervasive monitoring [RFC7258]. The privacy 188 information of the IPv6 host, such as DUID, may be gleaned to find 189 location information, previous visited networks and so on. [RFC7258] 190 claims that pervasive monitoring should be mitigated in the design of 191 IETF protocol, where possible. 193 To better address the problem of passive monitoring and to achieve 194 authentication without requiring a symmetric key distribution 195 solution for DHCP, this document defines an asymmetric key 196 authentication and encryption mechanism. This protects against both 197 active attacks, such as spoofing, and passive attacks, such as 198 pervasive monitoring. 200 5. Secure DHCPv6 Overview 202 5.1. Solution Overview 204 The following figure illustrated secure DHCPv6 procedure. Briefly, 205 this extension establishes the server's identity with an anonymous 206 Information-Request exchange. Once the server's identity has been 207 established, the client may either choose to communicate with the 208 server or not. Not communicating with an unknown server avoids 209 revealing private information, but if there is no known server on a 210 particular link, the client will be unable to communicate with a DHCP 211 server. 213 If the client chooses to communicate with a server, it uses the 214 Encrypted-Query message to encapsulate its communications to the DHCP 215 server. The server responds with Encrypted-Response messages. 216 Normal DHCP messages are encapsulated in these two new messages using 217 the new defined Encrypted-message option. Besides the Encrypted- 218 message option, the Signature option is defined to verify the 219 integrity of the DHCPv6 messages and then authentication of client 220 and server. The Increasing number option is defined to detect replay 221 attack. 223 +-------------+ +-------------+ 224 |DHCPv6 Client| |DHCPv6 Server| 225 +-------------+ +-------------+ 226 | Information-request | 227 |----------------------------------------->| 228 | Option Request option | 229 | | 230 | Reply | 231 |<-----------------------------------------| 232 | Certificate option | 233 | Signature option | 234 | Increasing-number option | 235 | Server Identifier option | 236 | | 237 | Encryption-Query | 238 |----------------------------------------->| 239 | Encrypted-message option | 240 | Server Identifier option | 241 | | 242 | Encryption-Response | 243 |<-----------------------------------------| 244 | Encrypted-message option | 245 | | 247 Figure 1: Secure DHCPv6 Procedure 249 5.2. New Components 251 The new components of the mechanism specified in this document are as 252 follows: 254 o Servers and clients that use certificates first generate a public/ 255 private key pair and then obtain a certificate that signs the 256 public key. The Certificate option is defined to carry the 257 certificate of the sender. 259 o A signature is generated using the private key to verify the 260 integrity of the DHCPv6 messages. The Signature option is defined 261 to carry the signature. 263 o A Increasing-number is used to detect replayed packet. The 264 Timestamp is one of the possible implementation choices. The 265 Increasing-number option is defined to carry a strictly-increasing 266 serial number. 268 o The Encrypted-message option contains the encrypted DHCPv6 269 message. 271 o The Encrypted-Query message is sent from the secure DHCPv6 client 272 to the secure DHCPv6 server. The Encrypted-Query message MUST 273 contain the Encrypted-message option. In addition, the Server 274 Identifier option MUST be contained if it is contained in the 275 original DHCPv6 message. The Encrypted-Query message MUST NOT 276 contain other options except the above options. 278 o The Encrypted-Response message is sent from the secure DHCPv6 279 server to the secure DHCPv6 client. The Encrypted-Response 280 message MUST contain the Encrypted-message option. The Encrypted- 281 Response message MUST NOT contain any other options except it. 283 5.3. Support for Algorithm Agility 285 In order to provide a means of addressing problems that may emerge 286 with existing hash algorithms, signature algorithm and encryption 287 algorithms in the future, this document provides a mechanism to 288 support algorithm agility. The support for algorithm agility in this 289 document is mainly a algorithm notification mechanism between the 290 client and the server. The same client and server SHOULD use the 291 same algorithm in a single communication session. The sender can 292 offer a set of algorithms, and then the receiver selects one 293 algorithm for the future communication. 295 If the server does not support the algorithm used by the client, the 296 server SHOULD reply with an AlgorithmNotSupported status code 297 (defined in Section 10.3) to the client. Upon receiving this status 298 code, the client MAY resend the message protected with the mandatory 299 algorithm. 301 5.4. Caused change to RFC3315 303 This protocol changes DHCPv6 message exchanges quite substantially: 304 previously, the client first sends a Solicit message, gets possibly 305 multiple Advertise messages, chooses the server (= sender of one of 306 the Advertises) that would be best for the client, and then sends a 307 Request to that chosen server. Now the server selection is done at 308 the key exchange phase (the initial Information-request and Reply 309 exchange). In addition, the Solicit and Rebind messages can be sent 310 only to a single server. If the client doesn't like the Advertise it 311 could restart the whole process, but it will be more expensive, and 312 there's no guarantee that other servers can provide a better 313 Advertise. For the privacy consideration, we have to give up the 314 previous server selection feature. 316 [RFC3315] provides an additional mechanism for preventing off-network 317 timing attacks using the Reconfigure message: the Reconfigure Key 318 authentication method. Secure DHCPv6 can protect the Reconfigure 319 message using the encryption method. So the Reconfigure Key 320 authentication method SHOULD NOT be used if Secure DHCPv6 is applied. 322 5.5. Applicability 324 In principle, secure DHCPv6 is applicable in any environment where 325 physical security on the link is not assured and attacks on DHCPv6 326 are a concern. In practice, however, authenticated and encrypted 327 DHCPv6 configuration will rely on some operational assumptions mainly 328 regarding public key distribution and management. In order to 329 achieve the more wide use of secure DHCPv6, opportunistic security 330 [RFC7435] can be applied to secure DHCPv6 deployment, which allows 331 DHCPv6 encryption in environments where support for authentication is 332 not available. 334 Secure DHCPv6 can achieve authentication and encryption based on pre- 335 sharing of authorized certificates. The One feasible environment in 336 an early deployment stage would be enterprise networks. In 337 enterprise networks, the client is manually pre-configured with the 338 trusted servers' public key and the server is also manually pre- 339 configured with the trusted clients' public keys. In some scenario, 340 such as coffee shop where the certificate cannot be validated and 341 don't want to be blocked from the Internet, then the DHCPv6 342 configuration process can be encrypted without authentication. 344 Note that this deployment scenario based on manual operation is not 345 different very much from the existing, shared-secret based 346 authentication mechanisms defined in [RFC3315] in terms of 347 operational costs. However, Secure DHCPv6 is still securer than the 348 shared-secret mechanism in that even if clients' keys stored for the 349 server are stolen that does not mean an immediate threat as these are 350 public keys. In addition, if some kind of PKI is used with Secure 351 DHCPv6, even if the initial installation of the certificates is done 352 manually, it will help reduce operational costs of revocation in case 353 a private key (especially that of the server) is compromised. 355 6. DHCPv6 Client Behavior 357 The secure DHCPv6 client is pre-configured with a certificate and its 358 corresponding private key for client authentication. If the client 359 is pre-configured with public key but not with a certificate, it can 360 generate the self-signed certificate. 362 The secure DHCPv6 client sends Information-request message as per 363 [RFC3315]. The Information-request message is used by the DHCPv6 364 client to request the server's identity verification information 365 without having addresses, prefixes or any non-security options 366 assigned to it. The Information-request message MUST NOT include any 367 other DHCPv6 options except the ORO option to minimize client's 368 privacy information leakage. The Option Request option in the 369 Information-request message MUST contain the option code of the 370 Certificate option. 372 When receiving the Reply messages from DHCPv6 servers, a secure 373 DHCPv6 client discards any DHCPv6 messages that meet any of the 374 following conditions: 376 o the Signature option is missing, 378 o multiple Signature options are present, 380 o the Certificate option is missing. 382 And then the client first checks the support of the hash algorithm, 383 signature algorithm and encryption algorithms that the server 384 supports. If the checks fails, the Reply message is dropped. If the 385 hash algorithm field is zero, then it indicates that the hash 386 algorithm is fixed according to the corresponding signature 387 algorithm. If all the algorithms are supported, then the client 388 selects one hash algorithm, signature algorithm and encryption 389 algorithm from the provided algorithms set. And then the client also 390 uses the same algorithms in the return messages. 392 Then the client checks the authority of the server. The client 393 validates the certificates through the pre-configured local trusted 394 certificates list or other methods. A certificate that finds a match 395 in the local trust certificates list is treated as verified. The 396 message transaction-id is used as the identifier of the authenticated 397 server's public key for further message encryption. At this point, 398 the client has either recognized the certificate of the server, or 399 decided to drop the message. 401 The client MUST now authenticate the server by verifying the 402 signature and checking increasing number, if there is a Increasing- 403 number option. The order of two procedures is left as an 404 implementation decision. It is RECOMMENDED to check increasing 405 number first, because signature verification is much more 406 computationally expensive. If the decrypted message contains the 407 Increasing-number option, the client checks it according to the rule 408 defined in Section 9.1. For the message without an Increasing-number 409 option, according to the client's local policy, it MAY be acceptable 410 or rejected. If the server rejects such a message, the increasing 411 number check fails. 413 The Signature field verification MUST show that the signature has 414 been calculated as specified in Section 10.1.2. Only the messages 415 that get through both the signature verification and increasing 416 number check (if there is a Increasing-number option) are accepted. 417 Reply message that does not pass the above tests MUST be discarded. 419 If there are multiple authenticated DHCPv6 certs, the client selects 420 one DHCPv6 cert. The client can also choose other implementation 421 method depending on the client's local policy if the defined protocol 422 can also run normally. For example, the client can try multiple 423 transactions (each encrypted with different public key) at the "same" 424 time. It should be noted that the selected certificate may 425 correspond to multiple DHCPv6 servers. 427 If there are no authenticated DHCPv6 certs or existing servers fail 428 authentication, the client should retry a number of times. The 429 client conducts the server discovery process as per section 18.1.5 of 430 [RFC3315] to avoid the packet storm. In this way, it is difficult 431 for the rogue server to beat out a busy "real" server. And then the 432 client takes some alternative action depending on its local policy, 433 such as attempting to use an unsecured DHCPv6 server. 435 Once the server has been authenticated, the DHCPv6 client sends the 436 Encrypted-Query message to the DHCPv6 server. The Encrypted-Query 437 message contains the Encrypted-message option, which MUST be 438 constructed as explained in Section 10.1.4. In addition, the Server 439 Identifier option MUST be included if it is in the original message 440 (i.e. Request, Renew, Decline, Release) to avoid the need for other 441 servers receiving the message to attempt to decrypt it. The 442 Encrypted-message option contains the DHCPv6 message that is 443 encrypted using the public key contained in the selected cert. The 444 Encrypted-Query message MUST NOT contain any other DHCPv6 option 445 except the Server Identifier option and Encrypted-Message option. 447 The first DHCPv6 message sent from the client to the server, such as 448 Solicit message, MUST contain the Certificate option, Signature 449 option and Increasing-number option for client authentication. The 450 encryption text SHOULD be formatted as explain in [RFC5652]. The 451 Certificate option MUST be constructed as explained in 452 Section 10.1.1. It should be noted that a client's certificate for 453 the mandatory algorithm MUST be contained to ensure that the Reply 454 message with the error code can be encrypted using the mandatory 455 algorithm. In addition, one and only one Signature option MUST be 456 contained, which MUST be constructed as explained in Section 10.1.2. 457 One and only one Increasing-number option SHOULD be contained, which 458 MUST be constructed as explained in Section 10.1.3. 460 If the client has multiple certificates with different public/private 461 key pairs, the message transaction-id is also used as the identifier 462 of the client's private key for decryption. In addition, the 463 subsequent encrypted DHCPv6 message can contain the Increasing-number 464 option to defend against replay attack. 466 For the received Encrypted-Response message, the client MUST drop the 467 Encrypted-Response message if other DHCPv6 option except Encrypted- 468 message option is contained. Then, the client extracts the 469 Encrypted-message option and decrypts it using its private key to 470 obtain the original DHCPv6 message. Then it handles the message as 471 per [RFC3315]. If the decrypted DHCPv6 message contains the 472 Increasing-number option, the DHCPv6 client checks it according to 473 the rule defined in Section 9.1. If the client fails to get the 474 proper parameters from the chosen server, it sends the Encrypted- 475 Query message to another authenticated server for parameters 476 configuration until the client obtains the proper parameters. 478 When the decrypted message is Reply message with an error status 479 code, the error status code indicates the failure reason on the 480 server side. According to the received status code, the client MAY 481 take follow-up action: 483 o Upon receiving an AlgorithmNotSupported error status code, the 484 client SHOULD resend the message protected with one of the 485 mandatory algorithms. 487 o Upon receiving an AuthenticationFail error status code, the client 488 is not able to build up the secure communication with the server. 489 However, there may be other DHCPv6 servers available that 490 successfully complete authentication. The client MAY use the 491 AuthenticationFail as a hint and switch to other certificate if it 492 has another one; but otherwise treat the message containing the 493 status code as if it had not been received. But it SHOULD NOT 494 retry with the same certificate. However, if the client decides 495 to retransmit using the same certificate after receiving 496 AuthenticationFail, it MUST NOT retransmit immediately and MUST 497 follow normal retransmission routines defined in [RFC3315]. 499 o Upon receiving a DecryptionFail error status code, the client MAY 500 resend the message following normal retransmission routines 501 defined in [RFC3315]. 503 o Upon receiving a ReplayDetected error status code, the client MAY 504 resend the message with an adjusted Increasing-number option 505 according to the returned number from the DHCPv6 server. 507 o Upon receiving a SignatureFail error status code, the client MAY 508 resend the message following normal retransmission routines 509 defined in [RFC3315]. 511 7. DHCPv6 Server Behavior 513 The secure DHCPv6 server is pre-configured with a certificate and its 514 corresponding private key for server authentication. If the server 515 is pre-configured with public key but not with a certificate, it can 516 generate the self-signed certificate. 518 When the DHCPv6 server receives the Information-request message and 519 the contained Option Request option identifies the request is for the 520 server certificate information, it replies with a Reply message to 521 the client. The Reply message MUST contain the requested Certificate 522 option, which MUST be constructed as explained in Section 10.1.1, and 523 Server Identifier option. In addition, the Reply message MUST 524 contain one and only one Signature option, which MUST be constructed 525 as explained in Section 10.1.2. Besides, the Reply message SHOULD 526 contain one and only one Increasing-number option, which MUST be 527 constructed as explained in Section 10.1.3. In addition, if client 528 authentication is needed, then the ORO option in the Reply message 529 contains the code of the certificate option to indicate the request 530 of the client certificate information. 532 Upon the receipt of Encrypted-Query message, the server MUST drop the 533 message if the other DHCPv6 option is contained except Server 534 Identifier option and Encrypted-message option. Then, the server 535 checks the Server Identifier option if the Encrypted-Query message 536 contains it. The DHCPv6 server drops the message that is not for it, 537 thus not paying cost to decrypt messages. It decrypts the Encrypted- 538 message option using its private key if it is the target server. If 539 the decryption fails, the server SHOULD send an encrypted Reply 540 message with a DecryptionFail error status code, defined in 541 Section 10.3, back to the client. 543 If secure DHCPv6 server needs client authentication and decrypted 544 message is a Solicit/Information-request message which contains the 545 information for client authentication, the secure DHCPv6 server 546 discards the received message that meets any of the following 547 conditions: 549 o the Signature option is missing, 551 o multiple Signature options are present, 553 o the Certificate option is missing. 555 In such failure, the server SHOULD send an encrypted Reply message 556 with an UnspecFail (value 1, [RFC3315]) error status code to the 557 client. 559 The server SHOULD first check the support of the hash function, 560 signature algorithm, encryption algorithm that the client supports. 561 If the hash algorithm field is zero, then the corresponding hash 562 algorithm is fixed according to the signature algorithm. If the 563 check fails, the server SHOULD reply with an AlgorithmNotSupported 564 error status code, defined in Section 10.3, back to the client. 565 Because the server does not support the acknowledged algorithm, the 566 Reply message with the AlgorithmNotSupported error status code is 567 encrypted with the mandatory algorithm. If all the algorithms are 568 supported, the server then uses the acknowledged algorithms in the 569 future communication. 571 The server validates the client's certificate through the local pre- 572 configured trusted certificates list. A certificate that finds a 573 match in the local trust certificates list is treated as verified. 574 The message that fails authentication validation MUST be dropped. In 575 such failure, the DHCPv6 server replies with an AuthenticationFail 576 error status code, defined in Section 10.3, back to the client. The 577 Reply message with the AuthenticationFail error status code is also 578 encrypted. At this point, the server has either recognized the 579 authentication of the client, or decided to drop the message. 581 If the decrypted message contains the Increasing-number option, the 582 server checks it according to the rule defined in Section 9.1. If 583 the check fails, an encrypted Reply message with a ReplayDetected 584 error status code, defined in Section 10.3, should be sent back to 585 the client. In addition, a Increasing-number option is carried to 586 indicate the server's stored number for the client to use. According 587 to the server's local policy, the message without an Increasing- 588 number option MAY be acceptable or rejected. If the server rejects 589 such a message, the server processes it as the increasing number 590 check fails. 592 The Signature field verification MUST show that the signature has 593 been calculated as specified in Section 10.1.2. If the signature 594 check fails, the DHCPv6 server SHOULD send an encrypted Reply message 595 with a SignatureFail error status code. Only the clients that get 596 through both the signature verification and increasing number check 597 (if there is a Increasing-number option) are accepted as 598 authenticated clients and continue to be handled their message as 599 defined in [RFC3315]. 601 Once the client has been authenticated, the DHCPv6 server sends the 602 Encrypted-response message to the DHCPv6 client. The Encrypted- 603 response message MUST only contain the Encrypted-message option, 604 which MUST be constructed as explained in Section 10.1.4. The 605 encryption text SHOULD be formatted as explain in [RFC5652]. The 606 Encrypted-message option contains the encrypted DHCPv6 message that 607 is encrypted using the authenticated client's public key. To provide 608 the replay protection, the Increasing-number option can be contained 609 in the encrypted DHCPv6 message. 611 8. Relay Agent Behavior 613 When a DHCPv6 relay agent receives an Encrypted-query or Encrypted- 614 response message, it may not recognize this message. The unknown 615 messages MUST be forwarded as described in [RFC7283]. 617 When a DHCPv6 relay agent recognizes the Encrypted-query and 618 Encrypted-response messages, it forwards the message according to 619 section 20 of [RFC3315]. There is nothing more the relay agents have 620 to do, it neither needs to verify the messages from client or server, 621 nor add any secure DHCPv6 options. Actually, by definition in this 622 document, relay agents MUST NOT add any secure DHCPv6 options. 624 Relay-forward and Relay-reply messages MUST NOT contain any 625 additional Certificate option or Increasing-number option, aside from 626 those present in the innermost encapsulated messages from the client 627 or server. 629 Relay agent is RECOMMENDED to cache server announcements to form the 630 list of the available DHCPv6 server certs. If the relay agent 631 receives the Information-request message, then it replies with a list 632 of server certs available locally. In this way, the client can be 633 confident of a quick response, and therefore treat the lack of a 634 quick response as an indication that no authenticated DHCP servers 635 exist. 637 9. Processing Rules 639 9.1. Increasing Number Check 641 In order to check the Increasing-number option, defined in 642 Section 10.1.3, the client/server has one stable stored number for 643 replay attack detection. The server should keep a record of the 644 increasing number forever. And the client keeps a record of the 645 increasing number during the transaction with the DHCPv6 server. In 646 addition, the client can forget the increasing number information 647 after the transaction is finished. 649 It is essential to remember that the increasing number is finite. 650 All arithmetic dealing with sequence numbers must be performed modulo 651 2^64. This unsigned arithmetic preserves the relationship of 652 sequence numbers as they cycle from 2^64 - 1 to 0 again. 654 In order to check the Increasing-number option, the following 655 comparison is needed. The symbol means "less or equal" (modulo 656 2^64). 658 NUM.STO = the stored number in the client/server 660 NUM.REC = the acknowledged number from the received message 662 The Increasing-number option in the received message passes the 663 increasing number check if NUM.REC is more than NUM.STO. And then, 664 the value of NUM.STO is changed into the value of NUM.REC. 666 The increasing number check fails if NUM.REC is equal or less than 667 NUM.STO 669 10. Extensions for Secure DHCPv6 671 This section describes the extensions to DHCPv6. Four new DHCPv6 672 options, two new DHCPv6 messages and five new status codes are 673 defined. 675 10.1. New DHCPv6 Options 677 10.1.1. Certificate Option 679 The Certificate option carries the certificate(s) of the client/ 680 server. The format of the Certificate option is described as 681 follows: 683 0 1 2 3 684 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 1 685 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 686 | OPTION_CERTIFICATE | option-len | 687 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 688 . EA-id List . 689 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 690 | | 691 . Certificate List(variable length) . 692 | | 693 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 695 Figure 2: Certificate Option 697 o option-code: OPTION_CERTIFICATE (TBA1). 699 o option-len: length of EA-id List + length of Certificate List in 700 octets. 702 o EA-id List: The format of the EA-id List field is shown in 703 Figure 3. 705 0 1 2 3 706 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 1 707 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 708 | EA-num | EA-id | 709 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 710 . ... . 711 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 712 | EA-id | 713 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 715 EA-num The number of the following EA-ids. 717 EA-id Encryption Algorithm id. The encryption algorithm 718 is used for the encrypted DHCPv6 configuration 719 process. This design is adopted in order to provide 720 encryption algorithm agility. The value is from the 721 Encryption Algorithm for Secure DHCPv6 registry in 722 IANA. A registry of the initial assigned values 723 is defined in Section 12. 725 Figure 3: EA-id List Field 727 o Certificate List: The format of the Certificate List Field is 728 shown in Figure 4. 730 0 1 2 3 731 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 1 732 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 733 | cert-num | cert-len | certificate | 734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 735 . ...Certificate(variable length)(cont) . 736 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 737 . . 738 . ... . 739 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 740 | cert-len | certificate | 741 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 742 . ...certificate(variable length)(cont) . 743 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 745 cert-num The number of the the following certificates. 747 cert-len The length of the certificate. 749 Certificate A variable-length field containing certificates. The 750 encoding of certificate and certificate data MUST 751 be in format as defined in Section 3.6, [RFC7296]. 752 The support of X.509 certificate is mandatory. 754 Figure 4: Certificate List Field 756 10.1.2. Signature option 758 The Signature option allows a signature that is signed by the private 759 key to be attached to a DHCPv6 message. The Signature option could 760 be in any place within the DHCPv6 message while it is logically 761 created after the entire DHCPv6 header and options. It protects the 762 entire DHCPv6 header and options, including itself. The format of 763 the Signature option is described as follows: 765 0 1 2 3 766 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 1 767 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 768 | OPTION_SIGNATURE | option-len | 769 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 770 . SA-id List . 771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 772 . HA-id List . 773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 774 | | 775 . Signature (variable length) . 776 . . 777 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 779 Figure 5: Signature Option 781 o option-code: OPTION_SIGNATURE (TBA2). 783 o option-len: length of SA-id list + length of HA-id list + length 784 of Signature field in octets. 786 o SA-id List: The format of the SA-id List field is shown in 787 Figure 6. 789 0 1 2 3 790 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 1 791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 792 | SA-num | SA-id | 793 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 794 . ... . 795 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 796 | SA-id | 797 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 799 SA-num The number of the following SA-ids. 801 SA-id Signature Algorithm id. The signature algorithm is 802 used for computing the signature result. This 803 design is adopted in order to provide signature 804 algorithm agility. The value is from the Signature 805 Algorithm for Secure DHCPv6 registry in IANA. The 806 support of RSASSA-PKCS1-v1_5 is mandatory. A 807 registry of the initial assigned values is defined 808 in Section 12. 810 Figure 6: EA-id List Field 812 o HA-id List: The format of the HA-id List field is shown in 813 Figure 7. 815 0 1 2 3 816 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 1 817 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 818 | HA-num | HA-id | 819 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 820 . ... . 821 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 822 | HA-id | 823 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 825 HA-num The number of the following HA-ids. 827 HA-id Hash Algorithm id. The hash algorithm is used for 828 computing the signature result. This design is 829 adopted in order to provide hash algorithm agility. 830 The value is from the Hash Algorithm for Secure 831 DHCPv6 registry in IANA. The support of SHA-256 is 832 mandatory. A registry of the initial assigned values 833 is defined in Section 12. If the signature algorithm 834 and hash algorithm cannot be separated, the HA-id 835 field is zero. The hash algorithm is decided by the 836 corresponding signature algorithm. 838 Figure 7: HA-id List Field 840 o Signature: A variable-length field containing a digital signature. 841 The signature value is computed with the hash algorithm and the 842 signature algorithm, as described in HA-id and SA-id. The 843 Signature field MUST be padded, with all 0, to the next octet 844 boundary if its size is not a multiple of 8 bits. The padding 845 length depends on the signature algorithm, which is indicated in 846 the SA-id field. 848 Note: If Secure DHCPv6 is used, the DHCPv6 message is encrypted in a 849 way that the authentication mechanism defined in RFC3315 does not 850 understand. So the Authentication option SHOULD NOT be used if 851 Secure DHCPv6 is applied. 853 10.1.3. Increasing-number Option 855 The Increasing-number option carries the number which is higher than 856 the local stored number on the client/server. It adds the anti- 857 replay protection to the DHCPv6 messages. It is optional. 859 0 1 2 3 860 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 1 861 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 862 | OPTION_INCREASING_NUM | option-len | 863 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 864 | | 865 | InreasingNum (64-bit) | 866 | | 867 | | 868 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 870 option-code OPTION_INCREASING_NUM (TBA3). 872 option-len 8, in octets. 874 IncreasingNum A strictly increasing number for the replay attack detection 875 which is more than the local stored number. 877 Figure 8: Incresing-number Option 879 10.1.4. Encrypted-message Option 881 The Encrypted-message option carries the encrypted DHCPv6 message 882 with the recipient's public key. 884 The format of the Encrypted-message option is: 886 0 1 2 3 887 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 1 888 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 889 | option-code | option-len | 890 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 891 | | 892 . encrypted DHCPv6 message . 893 . (variable) . 894 . . 895 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 897 Figure 1: Encrypted-message Option 899 option-code OPTION_ENCRYPTED_MSG (TBA4). 901 option-len Length of the encrypted DHCPv6 message. 903 encrypted DHCPv6 message A variable length field containing the 904 encrypted DHCPv6 message sent by the client or the server. In 905 Encrypted-Query message, it contains encrypted DHCPv6 message sent 906 by a client. In Encrypted-response message, it contains encrypted 907 DHCPv6 message sent by a server. 909 10.2. New DHCPv6 Messages 911 Two new DHCPv6 messages are defined to achieve the DHCPv6 encryption: 912 Encrypted-Query and Encrypted-Response. Both the DHCPv6 messages 913 defined in this document share the following format: 915 0 1 2 3 916 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 1 917 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 918 | msg-type | transaction-id | 919 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 920 | | 921 . options . 922 . (variable) . 923 | | 924 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 926 Figure 2: The format of Encrypted-Query and Encrypted-Response 927 Messages 929 msg-type Identifier of the message type. It can be either 930 Encrypted-Query (TBA5) or DHCPv6-Response (TBA6). 932 transaction-id The transaction ID for this message exchange. 934 options The Encrypted-Query message MUST contain the 935 Encrypted-message option and MUST contain the Server 936 Identifier option if the message in the Encrypted- 937 message option has a Server Identifier option. The 938 Encrypted-Response message MUST only contain the 939 Encrypted-message option. 941 10.3. Status Codes 943 The following new status codes, see Section 5.4 of [RFC3315] are 944 defined. 946 o AlgorithmNotSupported (TBD7): indicates that the DHCPv6 server 947 does not support algorithms that sender used. 949 o AuthenticationFail (TBD8): indicates that the message from the 950 DHCPv6 client fails authentication check. 952 o ReplayDetected (TBD9): indicates the message from DHCPv6 client 953 fails the increasing number check. 955 o SignatureFail (TBD10): indicates the message from DHCPv6 client 956 fails the signature check. 958 o DecryptionFail (TBD11): indicates the message from DHCPv6 client 959 fails the DHCPv6 message decryption. 961 11. Security Considerations 963 This document provides the authentication and encryption mechanisms 964 for DHCPv6. 966 [RFC6273] has analyzed possible threats to the hash algorithms used 967 in SEND. Since Secure DHCPv6 defined in this document uses the same 968 hash algorithms in similar way to SEND, analysis results could be 969 applied as well: current attacks on hash functions do not constitute 970 any practical threat to the digital signatures used in the signature 971 algorithm in Secure DHCPv6. 973 A server, whose local policy accepts messages without a Increasing- 974 number option, may have to face the risk of replay attacks. 976 There are some mandatory algorithm for encryption algorithm in this 977 document. It may be at some point that the mandatory algorithm is no 978 longer safe to use. 980 If the client tries more than one cert for client authentication, the 981 server can easily get a client that implements this to enumerate its 982 entire cert list and probably learn a lot about a client that way. 984 12. IANA Considerations 986 This document defines four new DHCPv6 [RFC3315] options. The IANA is 987 requested to assign values for these four options from the DHCPv6 988 Option Codes table of the DHCPv6 Parameters registry maintained in 989 http://www.iana.org/assignments/dhcpv6-parameters. The four options 990 are: 992 The Certificate Option (TBA1), described in Section 10.1.1. 994 The Signature Option (TBA2), described in Section 10.1.2. 996 The Increasing-number Option (TBA3),described in Section 10.1.3. 998 The Encrypted-message Option (TBA4), described in Section 10.1.4. 1000 The IANA is also requested to assign value for these two messages 1001 from the DHCPv6 Message Types table of the DHCPv6 Parameters registry 1002 maintained in http://www.iana.org/assignments/dhcpv6-parameters. The 1003 two messages are: 1005 The Encrypted-Query Message (TBA5), described in Section 10.2. 1007 The Encrypted-Response Message (TBA6), described in Section 10.2. 1009 The IANA is also requested to add three new registry tables to the 1010 DHCPv6 Parameters registry maintained in 1011 http://www.iana.org/assignments/dhcpv6-parameters. The three tables 1012 are the Hash Algorithm for Secure DHCPv6 table, the Signature 1013 Algorithm for Secure DHCPv6 table and the Encryption Algorithm for 1014 Secure DHCPv6 table. 1016 Initial values for these registries are given below. Future 1017 assignments are to be made through Standards Action [RFC5226]. 1018 Assignments for each registry consist of a name, a value and a RFC 1019 number where the registry is defined. 1021 Hash Algorithm for Secure DHCPv6. The values in this table are 8-bit 1022 unsigned integers. The following initial values are assigned for 1023 Hash Algorithm for Secure DHCPv6 in this document: 1025 Name | Value | RFCs 1026 -------------------+---------+-------------- 1027 SigAlg-Combined | ox00 | this document 1028 SHA-256 | 0x01 | this document 1029 SHA-512 | 0x02 | this document 1031 Signature Algorithm for Secure DHCPv6. The values in this table are 1032 8-bit unsigned integers. The following initial values are assigned 1033 for Signature Algorithm for Secure DHCPv6 in this document: 1035 Name | Value | RFCs 1036 -------------------+---------+-------------- 1037 RSASSA-PKCS1-v1_5 | 0x01 | this document 1039 Encryption algorithm for Secure DHCPv6. The values in this table are 1040 8-bit unsigned integers. The following initial values are assigned 1041 for encryption algorithm for Secure DHCPv6 in this document: 1043 Name | Value | RFCs 1044 -------------------+---------+-------------- 1045 RSA | 0x01 | this document 1047 IANA is requested to assign the following new DHCPv6 Status Codes, 1048 defined in Section 10.3, in the DHCPv6 Parameters registry maintained 1049 in http://www.iana.org/assignments/dhcpv6-parameters: 1051 Code | Name | Reference 1052 ---------+-----------------------+-------------- 1053 TBD7 | AlgorithmNotSupported | this document 1054 TBD8 | AuthenticationFail | this document 1055 TBD9 | ReplayDetected | this document 1056 TBD10 | SignatureFail | this document 1057 TBD11 | DecryptionFail | this document 1059 13. Acknowledgements 1061 The authors would like to thank Tomek Mrugalski, Bernie Volz, 1062 Jianping Wu, Randy Bush, Yiu Lee, Sean Shen, Ralph Droms, Jari Arkko, 1063 Sean Turner, Stephen Farrell, Christian Huitema, Stephen Kent, Thomas 1064 Huth, David Schumacher, Francis Dupont, Gang Chen, Suresh Krishnan, 1065 Fred Templin, Robert Elz, Nico Williams, Erik Kline, Alan DeKok, 1066 Bernard Aboba, Sam Hartman, Qi Sun, Zilong Liu and other members of 1067 the IETF DHC working group for their valuable comments. 1069 This document was produced using the xml2rfc tool [RFC2629]. 1071 14. Change log [RFC Editor: Please remove] 1073 draft-ietf-dhc-sedhcpv6-15: Increasing number option only contains 1074 the strictly increasing number; Add some description about why 1075 encryption is needed in Security Issues of DHCPv6 part; For the 1076 algorithm agility part, the provider can offer multiple EA-id, SA-id, 1077 HA-id and then receiver choose one from the algorithm set. 1079 draft-ietf-dhc-sedhcpv6-14: For the deployment part, Tofu is out of 1080 scope and take Opportunistic security into consideration; Increasing 1081 number option is changed into 64 bits; Increasing number check is a 1082 separate section; IncreasingnumFail error status code is changed into 1083 ReplayDetected error status code; Add the section of "caused change 1084 to RFC3315"; 1086 draft-ietf-dhc-sedhcpv6-13: Change the Timestamp option into 1087 Increasing-number option and the corresponding check method; Delete 1088 the OCSP stampling part for the certificate check; Add the scenario 1089 where the hash and signature algorithms cannot be separated; Add the 1090 comparison with RFC7824 and RFC7844; Add the encryption text format 1091 and reference of RFC5652. Add the consideration of scenario where 1092 multiple DHCPv6 servers share one common DHCPv6 server. Add the 1093 statement that Encrypted-Query and Encrypted-Response messages can 1094 only contain certain options: Server Identifier option and Encrypted- 1095 message option. Add opportunistic security for deployment 1096 consideration. Besides authentication+encyrption mode, encryption- 1097 only mode is added. 1099 draft-ietf-dhc-sedhcpv6-12: Add the Signature option and timestamp 1100 option during server/client authentication process. Add the hash 1101 function and signature algorithm. Add the requirement: The 1102 Information-request message cannot contain any other options except 1103 ORO option. Modify the use of "SHOULD"; Delete the reference of 1104 RFC5280 and modify the method of client/server cert verification; Add 1105 the relay agent cache function for the quick response when there is 1106 no authenticated server. 2016-4-24. 1108 draft-ietf-dhc-sedhcpv6-11: Delete the Signature option, because the 1109 encrypted DHCPv6 message and the Information-request message (only 1110 contain the Certificate option) don't need the Signature option for 1111 message integrity check; Rewrite the "Applicability" section; Add the 1112 encryption algorithm negotiation process; To support the encryption 1113 algorithm negotiation, the Certificate option contains the EA- 1114 id(encryption algorithm identifier) field; Reserve the Timestamp 1115 option to defend against the replay attacks for encrypted DHCPv6 1116 configuration process; Modify the client behavior when there is no 1117 authenticated DHCPv6 server; Add the DecryptionFail error code. 1118 2016-3-9. 1120 draft-ietf-dhc-sedhcpv6-10: merge DHCPv6 authentication and DHCPv6 1121 encryption. The public key option is removed, because the device can 1122 generate the self-signed certificate if it is pre-configured the 1123 public key not the certificate. 2015-12-10. 1125 draft-ietf-dhc-sedhcpv6-09: change some texts about the deployment 1126 part.2015-12-10. 1128 draft-ietf-dhc-sedhcpv6-08: clarified what the client and the server 1129 should do if it receives a message using unsupported algorithm; 1130 refined the error code treatment regarding to AuthenticationFail and 1131 TimestampFail; added consideration on how to reduce the DoS attack 1132 when using TOFU; other general editorial cleanups. 2015-06-10. 1134 draft-ietf-dhc-sedhcpv6-07: removed the deployment consideration 1135 section; instead, described more straightforward use cases with TOFU 1136 in the overview section, and clarified how the public keys would be 1137 stored at the recipient when TOFU is used. The overview section also 1138 clarified the integration of PKI or other similar infrastructure is 1139 an open issue. 2015-03-23. 1141 draft-ietf-dhc-sedhcpv6-06: remove the limitation that only clients 1142 use PKI- certificates and only servers use public keys. The new text 1143 would allow clients use public keys and servers use PKI-certificates. 1144 2015-02-18. 1146 draft-ietf-dhc-sedhcpv6-05: addressed comments from mail list that 1147 responsed to the second WGLC. 2014-12-08. 1149 draft-ietf-dhc-sedhcpv6-04: addressed comments from mail list. 1150 Making timestamp an independent and optional option. Reduce the 1151 serverside authentication to base on only client's certificate. 1152 Reduce the clientside authentication to only Leaf of Faith base on 1153 server's public key. 2014-09-26. 1155 draft-ietf-dhc-sedhcpv6-03: addressed comments from WGLC. Added a 1156 new section "Deployment Consideration". Corrected the Public Key 1157 Field in the Public Key Option. Added consideration for large DHCPv6 1158 message transmission. Added TimestampFail error code. Refined the 1159 retransmission rules on clients. 2014-06-18. 1161 draft-ietf-dhc-sedhcpv6-02: addressed comments (applicability 1162 statement, redesign the error codes and their logic) from IETF89 DHC 1163 WG meeting and volunteer reviewers. 2014-04-14. 1165 draft-ietf-dhc-sedhcpv6-01: addressed comments from IETF88 DHC WG 1166 meeting. Moved Dacheng Zhang from acknowledgement to be co-author. 1167 2014-02-14. 1169 draft-ietf-dhc-sedhcpv6-00: adopted by DHC WG. 2013-11-19. 1171 draft-jiang-dhc-sedhcpv6-02: removed protection between relay agent 1172 and server due to complexity, following the comments from Ted Lemon, 1173 Bernie Volz. 2013-10-16. 1175 draft-jiang-dhc-sedhcpv6-01: update according to review comments from 1176 Ted Lemon, Bernie Volz, Ralph Droms. Separated Public Key/ 1177 Certificate option into two options. Refined many detailed 1178 processes. 2013-10-08. 1180 draft-jiang-dhc-sedhcpv6-00: original version, this draft is a 1181 replacement of draft-ietf-dhc-secure-dhcpv6, which reached IESG and 1182 dead because of consideration regarding to CGA. The authors followed 1183 the suggestion from IESG making a general public key based mechanism. 1184 2013-06-29. 1186 15. References 1188 15.1. Normative References 1190 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1191 Requirement Levels", BCP 14, RFC 2119, 1192 DOI 10.17487/RFC2119, March 1997, 1193 . 1195 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 1196 (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, 1197 December 1998, . 1199 [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, 1200 C., and M. Carney, "Dynamic Host Configuration Protocol 1201 for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July 1202 2003, . 1204 [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, 1205 "SEcure Neighbor Discovery (SEND)", RFC 3971, 1206 DOI 10.17487/RFC3971, March 2005, 1207 . 1209 [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet 1210 Control Message Protocol (ICMPv6) for the Internet 1211 Protocol Version 6 (IPv6) Specification", RFC 4443, 1212 DOI 10.17487/RFC4443, March 2006, 1213 . 1215 [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, 1216 RFC 5652, DOI 10.17487/RFC5652, September 2009, 1217 . 1219 [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, 1220 "Network Time Protocol Version 4: Protocol and Algorithms 1221 Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010, 1222 . 1224 [RFC7283] Cui, Y., Sun, Q., and T. Lemon, "Handling Unknown DHCPv6 1225 Messages", RFC 7283, DOI 10.17487/RFC7283, July 2014, 1226 . 1228 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 1229 Kivinen, "Internet Key Exchange Protocol Version 2 1230 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 1231 2014, . 1233 [RFC7435] Dukhovni, V., "Opportunistic Security: Some Protection 1234 Most of the Time", RFC 7435, DOI 10.17487/RFC7435, 1235 December 2014, . 1237 [RFC7824] Krishnan, S., Mrugalski, T., and S. Jiang, "Privacy 1238 Considerations for DHCPv6", RFC 7824, 1239 DOI 10.17487/RFC7824, May 2016, 1240 . 1242 [RFC7844] Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity 1243 Profiles for DHCP Clients", RFC 7844, 1244 DOI 10.17487/RFC7844, May 2016, 1245 . 1247 15.2. Informative References 1249 [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, 1250 DOI 10.17487/RFC2629, June 1999, 1251 . 1253 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1254 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1255 DOI 10.17487/RFC5226, May 2008, 1256 . 1258 [RFC6273] Kukec, A., Krishnan, S., and S. Jiang, "The Secure 1259 Neighbor Discovery (SEND) Hash Threat Analysis", RFC 6273, 1260 DOI 10.17487/RFC6273, June 2011, 1261 . 1263 [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an 1264 Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May 1265 2014, . 1267 [RSA] RSA Laboratories, "RSA Encryption Standard, Version 2.1, 1268 PKCS 1", November 2002. 1270 Authors' Addresses 1272 Sheng Jiang 1273 Huawei Technologies Co., Ltd 1274 Q14, Huawei Campus, No.156 Beiqing Road 1275 Hai-Dian District, Beijing, 100095 1276 CN 1278 Email: jiangsheng@huawei.com 1280 Lishan Li 1281 Tsinghua University 1282 Beijing 100084 1283 P.R.China 1285 Phone: +86-15201441862 1286 Email: lilishan48@gmail.com 1287 Yong Cui 1288 Tsinghua University 1289 Beijing 100084 1290 P.R.China 1292 Phone: +86-10-6260-3059 1293 Email: yong@csnet1.cs.tsinghua.edu.cn 1295 Tatuya Jinmei 1296 Infoblox Inc. 1297 3111 Coronado Drive 1298 Santa Clara, CA 1299 US 1301 Email: jinmei@wide.ad.jp 1303 Ted Lemon 1304 Nominum, Inc. 1305 2000 Seaport Blvd 1306 Redwood City, CA 94063 1307 USA 1309 Phone: +1-650-381-6000 1310 Email: Ted.Lemon@nominum.com 1312 Dacheng Zhang 1313 Beijing 1314 CN 1316 Email: dacheng.zhang@gmail.com