idnits 2.17.1 draft-kampati-ipsecme-ikev2-sa-ts-payloads-opt-07.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (23 July 2021) is 1001 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Missing Reference: 'TBD1' is mentioned on line 240, but not defined == Missing Reference: 'TBD2' is mentioned on line 265, but not defined Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IPSECME Working Group S. Kampati 3 Internet-Draft W. Pan 4 Intended status: Standards Track Huawei 5 Expires: 24 January 2022 P. Wouters 6 Aiven 7 M. Bharath 8 Mavenir 9 M. Chen 10 CMCC 11 23 July 2021 13 IKEv2 Optional SA&TS Payloads in Child Exchange 14 draft-kampati-ipsecme-ikev2-sa-ts-payloads-opt-07 16 Abstract 18 This document describes a method for reducing the size of the 19 Internet Key Exchange version 2 (IKEv2) CREATE_CHILD_SA exchanges 20 used for rekeying of the IKE or Child SA by replacing the SA and TS 21 payloads with a Notify Message payload. Reducing size and complexity 22 of IKEv2 exchanges is especially useful for low power consumption 23 battery powered devices. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on 24 January 2022. 42 Copyright Notice 44 Copyright (c) 2021 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 49 license-info) in effect on the date of publication of this document. 50 Please review these documents carefully, as they describe your rights 51 and restrictions with respect to this document. Code Components 52 extracted from this document must include Simplified BSD License text 53 as described in Section 4.e of the Trust Legal Provisions and are 54 provided without warranty as described in the Simplified BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. Conventions Used in This Document . . . . . . . . . . . . . . 3 60 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 61 3. Negotiation of Support for OPTIMIZED REKEY . . . . . . . . . 4 62 4. Optimized Rekey of the IKE SA . . . . . . . . . . . . . . . . 4 63 5. Optimized Rekey of Child SAs . . . . . . . . . . . . . . . . 5 64 6. Payload Formats . . . . . . . . . . . . . . . . . . . . . . . 5 65 6.1. OPTIMIZED_REKEY_SUPPORTED Notify . . . . . . . . . . . . 5 66 6.2. OPTIMIZED_REKEY Notify . . . . . . . . . . . . . . . . . 6 67 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 68 8. Operational Considerations . . . . . . . . . . . . . . . . . 7 69 9. Security Considerations . . . . . . . . . . . . . . . . . . . 7 70 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7 71 11. Normative References . . . . . . . . . . . . . . . . . . . . 7 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 74 1. Introduction 76 The Internet Key Exchange protocol version 2 (IKEv2) [RFC7296] is 77 used to negotiate Security Association (SA) parameters for the IKE SA 78 and the Child SAs. Cryptographic key material for these SAs have a 79 limited lifetime before it needs to be refreshed, a process referred 80 to as "rekeying". IKEv2 uses the CREATE_CHILD_SA exchange to rekey 81 either the IKE SA or the Child SAs. 83 When rekeying, a full set of previously negotiated parameters are 84 exchanged. However, most of these parameters will be the same, and 85 some of these parameters MUST be the same. 87 For example, the Traffic Selector (TS) negotiated for the new Child 88 SA MUST cover the Traffic Selectors negotiated for the old Child SA. 89 And in practically all cases, a new Child SA would not need to cover 90 more Traffic Selectors. In the rare case where this would be needed, 91 a new Child SA could be negotiated instead of the current Child SA 92 being rekeyed. Similarly, IKEv2 states that the cryptographic 93 parameters negotiated for rekeying SHOULD NOT be different. This 94 means that the security properties of the IKE or Child SA in practise 95 do not change during a typical rekey. 97 This document specifies a method to omit these parameters and replace 98 them with a single Notify Message declaring that all these parameters 99 are identical to the originally negotiated parameters. 101 For security gateways/ePDG in 4G networks or cRAN/Cloud gateways in 102 5G networks, gateways typically support more than 100,000 IKE/IPSec 103 tunnels. At any point in time, there will be hundreds or thousands 104 of IKE SAs and Child SAs that are being rekeyed. This takes a large 105 amount of bandwidth and CPU power and any protocol simplification or 106 bandwidth reducing would result in an significant resource saving. 108 For Internet of Things (IoT) devices which utilize low power 109 consumption technology, reducing the size of rekey exchange reduces 110 its power consumption, as sending bytes over the air is usually the 111 most power consuming operation of such a device. Reducing the CPU 112 operations required to verify the rekey exchanges parameters will 113 also save power and extend the lifetime for these devices. 115 When using identical parameters during the IKE or Child SA rekey, the 116 SA and TS payloads can be omitted. For an IKE SA rekey, instead of 117 the (large) SA payload, only a Key Exchange (KE) payload and a new 118 Notify Type payload with the new SPI is required. For a Child SA 119 payload, instead of the SA or TS payloads, only an optional Nonce 120 payload (when using PFS) and a new Notify Type payload with the new 121 SPI is needed. This makes the rekey exchange packets much smaller 122 and the peers do not need to verify that the SA or TS parameters are 123 compatible with the old SA. 125 2. Conventions Used in This Document 127 2.1. Requirements Language 129 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 130 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 131 "OPTIONAL" in this document are to be interpreted as described in BCP 132 14 [RFC2119] [RFC8174] when, and only when, they appear in all 133 capitals, as shown here. 135 3. Negotiation of Support for OPTIMIZED REKEY 137 To indicate support for the optimized rekey negotiation, the 138 initiator includes the OPTIMIZED_REKEY_SUPPORTED Notify payload in 139 the IKE_AUTH exchange request. A responder that supports the 140 optimized rekey exchange includes the OPTIMIZED_REKEY_SUPPORTED 141 Notify payload in its response. Note that the notify indicates 142 support for optimized rekey for both IKE and Child SAs. 144 When a peer wishes to rekey an IKE SA or Child SA, it MAY use the 145 optimized rekey method during the CREATE_CHILD_SA exchange. A 146 responder MUST accept that the initiator uses a regular or optimized 147 rekey. 149 The IKE_AUTH message exchange in this case is shown below: 151 Initiator Responder 152 -------------------------------------------------------------------- 153 HDR, SK {IDi, [CERT,] [CERTREQ,] 154 [IDr,] AUTH, SAi2, TSi, TSr, 155 N(OPTIMIZED_REKEY_SUPPORTED)} --> 156 <-- HDR, SK {IDr, [CERT,] AUTH, 157 SAr2, TSi, TSr, 158 N(OPTIMIZED_REKEY_SUPPORTED)} 160 If the responder does not support this extension, as per regular 161 IKEv2 processing, it MUST ignore the unknown Notify payload. The 162 initiator will notice the lack of the OPTIMIZED_REKEY_SUPPORTED 163 Notify in the reply and thus know it cannot use the optimized rekey 164 method. 166 4. Optimized Rekey of the IKE SA 168 The initiator of an optimized rekey request sends a CREATE_CHILD_SA 169 payload with the OPTIMIZED_REKEY notify payload containing the new 170 Security Parameter Index (SPI) for the new IKE SA. It omits the SA 171 payload. 173 The responder of an optimized rekey request performs the same 174 process. It includes the OPTIMIZED_REKEY notify with its new IKE SPI 175 and omits the SA payload. 177 Both parties send Nonce and KE payloads just as they would do for a 178 regular IKE SA rekey. 180 The CREATE_CHILD_SA message exchange in this case is shown below: 182 Initiator Responder 183 -------------------------------------------------------------------- 184 HDR, SK {N(OPTIMIZED_REKEY), 185 Ni, KEi} --> 186 <-- HDR, SK {N(OPTIMIZED_REKEY), 187 Nr, KEr} 189 5. Optimized Rekey of Child SAs 191 The initiator of an optimized rekey request sends a CREATE_CHILD_SA 192 payload with the OPTIMIZED_REKEY notify payload containing the new 193 Security Parameter Index (SPI) for the new Child SA. It omits the SA 194 and TS payloads. If the current Child SA was negotiated with Perfect 195 Forward Secrecy (PFS), a KEi payload MUST be included as well. If no 196 PFS was negotiated for the current Child SA, a KEi payload MUST NOT 197 be included. 199 The responder of an optimized rekey request performs the same 200 process. It includes the OPTIMIZED_REKEY notify with its new IKE SPI 201 and omits the SA and TS payloads. Depending on the PFS negotiation 202 of the current Child SA, the responder includes a KEr payload. 204 Both parties send Nonce payloads just as they would do for a regular 205 Child SA rekey. 207 Using the received old SPI from the REKEY_SA payload and the new SPI 208 received from the OPTIMIZED_REKEY payload, both parties can perform 209 the Child SA rekey operation. 211 The CREATE_CHILD_SA message exchange in this case is shown below: 213 Initiator Responder 214 -------------------------------------------------------------------- 215 HDR, SK {N(REKEY_SA), N(OPTIMIZED_REKEY), 216 Ni, [KEi,]} --> 217 <-- HDR, SK {N(OPTIMIZED_REKEY), 218 Nr, [KEr,]} 220 6. Payload Formats 222 6.1. OPTIMIZED_REKEY_SUPPORTED Notify 224 The OPTIMIZED_REKEY_SUPPORTED Notify Message type notification is 225 used by the initiator and responder to indicate their support for the 226 optimized rekey negotiation. 228 1 2 3 229 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 1 230 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 231 | Next Payload |C| RESERVED | Payload Length | 232 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 233 |Protocol ID(=0)| SPI Size (=0) | Notify Message Type | 234 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 236 * Protocol ID (1 octet) - MUST be 0. 238 * SPI Size (1 octet) - MUST be 0, meaning no SPI is present. 240 * Notify Message Type (2 octets) - MUST be set to the value [TBD1]. 242 This Notify Message type contains no data. 244 6.2. OPTIMIZED_REKEY Notify 246 The OPTIMIZED_REKEY Notify Message type is used to perform an 247 optimized IKE SA or Child SA rekey. 249 0 1 2 3 250 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 1 251 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 252 | Next Payload |C| RESERVED | Payload Length | 253 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 |Protocol ID | SPI Size (=8) | Notify Message Type | 255 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 256 | Security Parameter Index (SPI) | 257 | | 258 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 260 * Protocol ID (1 octet) - MUST be 1. 262 * SPI Size (1 octet) - MUST be 8 when rekeying an IKE SA. MUST be 4 263 when rekeying a Child SA. 265 * Notify Message Type (2 octets) - MUST be set to the value [TBD2]. 267 * SPI (4 octets or 8 octets) - Security Parameter Index. The peer's 268 new SPI. 270 7. IANA Considerations 272 This document defines two new Notify Message Types in the "IKEv2 273 Notify Message Types - Status Types" registry. IANA is requested to 274 assign codepoints in this registry. 276 NOTIFY messages: status types Value 277 ---------------------------------------------------------- 278 OPTIMIZED_REKEY_SUPPORTED TBD1 279 OPTIMIZED_REKEY TBD2 281 8. Operational Considerations 283 Some implementations allow sending rekey messages with a different 284 set of Traffic Selectors or cryptographic parameters in response to a 285 configuration update. IKEv2 states this SHOULD NOT be done. Whether 286 or not optimized rekeying is used, a configuration change that 287 changes the Traffic Selectors or cryptographic parameters MUST NOT 288 use the optimized rekey method. It SHOULD also not use a regular 289 rekey method but instead start an entire new IKE and Child SA 290 negotiation with the new parameters. 292 9. Security Considerations 294 The optimized rekey removes sending unnecessary new parameters that 295 originally would have to be validated against the original 296 parameters. In that sense, this optimization enhances the security 297 of the rekey process. 299 10. Acknowledgments 301 Special thanks go to Paul Wouters, Valery Smyslov, and Antony Antony. 303 11. Normative References 305 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 306 Requirement Levels", BCP 14, RFC 2119, 307 DOI 10.17487/RFC2119, March 1997, 308 . 310 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 311 Kivinen, "Internet Key Exchange Protocol Version 2 312 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 313 2014, . 315 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 316 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 317 May 2017, . 319 Authors' Addresses 321 Sandeep Kampati 322 Huawei Technologies 323 Divyashree Techno Park, Whitefield 324 Bangalore 560066 325 Karnataka 326 India 328 Email: sandeepkampati@huawei.com 330 Wei Pan 331 Huawei Technologies 332 101 Software Avenue, Yuhuatai District 333 Nanjing 334 Jiangsu, 335 China 337 Email: william.panwei@huawei.com 339 Paul Wouters 340 Aiven 342 Email: paul.wouters@aiven.io 344 Meduri S S Bharath 345 Mavenir Systems Pvt Ltd 346 Manyata Tech Park 347 Bangalore 348 Karnataka 349 India 351 Email: bharath.meduri@mavenir.com 353 Meiling Chen 354 China Mobile 355 32 Xuanwumen West Street, West District 356 Beijing 357 Beijing, 100053 358 China 360 Email: chenmeiling@chinamobile.com