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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (July 1, 2009) is 5406 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: 'IDr' is mentioned on line 171, but not defined ** Obsolete normative reference: RFC 4306 (Obsoleted by RFC 5996) ** Obsolete normative reference: RFC 4718 (Obsoleted by RFC 5996) Summary: 3 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group Y. Nir 3 Internet-Draft Check Point 4 Intended status: Standards Track H. Tschofenig 5 Expires: January 2, 2010 NSN 6 H. Deng 7 China Mobile 8 R. Singh 9 Cisco 10 July 1, 2009 12 A Childless Initiation of the IKE SA 13 draft-nir-ipsecme-childless-00 15 Status of this Memo 17 This Internet-Draft is submitted to IETF in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF), its areas, and its working groups. Note that 22 other groups may also distribute working documents as Internet- 23 Drafts. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 The list of current Internet-Drafts can be accessed at 31 http://www.ietf.org/ietf/1id-abstracts.txt. 33 The list of Internet-Draft Shadow Directories can be accessed at 34 http://www.ietf.org/shadow.html. 36 This Internet-Draft will expire on January 2, 2010. 38 Copyright Notice 40 Copyright (c) 2009 IETF Trust and the persons identified as the 41 document authors. All rights reserved. 43 This document is subject to BCP 78 and the IETF Trust's Legal 44 Provisions Relating to IETF Documents in effect on the date of 45 publication of this document (http://trustee.ietf.org/license-info). 46 Please review these documents carefully, as they describe your rights 47 and restrictions with respect to this document. 49 Abstract 51 This document describes an extension to the IKEv2 protocol that 52 allows an IKE SA to be created and authenticated without generating a 53 child SA. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 58 1.1. Conventions Used in This Document . . . . . . . . . . . . . 3 59 2. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . . 3 60 3. Protocol Outline . . . . . . . . . . . . . . . . . . . . . . . 4 61 4. VID Payload . . . . . . . . . . . . . . . . . . . . . . . . . . 4 62 5. Modified IKE_AUTH Exchange . . . . . . . . . . . . . . . . . . 5 63 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 64 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 65 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 66 8.1. Normative References . . . . . . . . . . . . . . . . . . . 6 67 8.2. Informative References . . . . . . . . . . . . . . . . . . 6 68 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 70 1. Introduction 72 IKEv2, as specified in [RFC4306] requires that in an IKE_AUTH 73 exchange, a child SA is created along with the IKE SA. This 74 requirement is sometimes inconvenient, as some implementations need 75 to use IKE for authentication only, while other implementations would 76 like to set up the IKE SA before there is any actual traffic to 77 protect. 79 An IKE SA without any child SA is not a fruitless endeavor. Even 80 without Child SAs, an IKE SA allows: 81 o Checking the liveness status of the peer via liveness checks. 82 o Quickly setting up child SAs without public key operations, and/or 83 without user interaction. 84 o Authentication of the peer. 86 1.1. Conventions Used in This Document 88 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 89 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 90 document are to be interpreted as described in [RFC2119]. 92 2. Usage Scenarios 94 Several scenarios motivated this proposal: 95 o Interactive remote access VPN: the user tells the client to 96 "connect", which may involve interactive authentication. There is 97 still no traffic, but some may come later. Since there is no 98 traffic, it is impossible for the gateway to know what selectors 99 to use (how to narrow down the client's proposal). 100 o Location aware security, as in [SecureBeacon]. The user is 101 roaming between trusted and untrusted networks. While in an 102 untrusted network, all traffic should be encrypted, but on the 103 trusted network, only the IKE SA needs to be maintained. 104 o An IKE SA may be needed between peers even when there is not IPsec 105 traffic. Such IKE peers use liveness checks, and report to the 106 administrator the status of the "VPN links". 107 o IKE may be used on some physically secure links, where 108 authentication is necessary, but traffic protection is not. An 109 example of this in the PON links as described in [3GPP.33.820]. 110 o A node receiving IPsec traffic with an unrecognized SPI should 111 send an INVALID_SPI notification. If this traffic comes from a 112 peer, which it recognizes based on its IP address, then this node 113 may set up an IKE SA so as to be able to send the notification in 114 a protected IKE_INFORMATIONAL exchange. 116 o A future extension may have IKE SAs used for generating keying 117 material for applications, without ever requiring child SAs. This 118 is similar to what [extractors] is doing in TLS. 120 In some of these cases it may be possible to create a dummy Child SA 121 and then remove it, but this creates undesirable side effects and 122 race conditions. Moreover, the IKE peer might see the deletion of 123 the Child SA as a reason to delete the IKE SA. 125 3. Protocol Outline 127 The decision of whether or not to support an IKE_AUTH exchage without 128 the piggy-backed child SA negotiation is ultimately up to the 129 reponsder. A supporting resonder MUST include the VID payload, 130 described in Section 4, within the IKE_SA_INIT response. 132 A supporting initiator MAY send the modified IKE_AUTH request, 133 described in Section 5, if the VID payload was included in the 134 IKE_SA_INIT response. The initiator MUST NOT send the modified 135 IKE_AUTH request if the VID was not present. 137 A supporting responder that advertised the VID payload in the 138 IKE_SA_INIT response MUST process a modified IKE_AUTH request, and 139 MUST reply with a modified IKE_AUTH response. Such a responder MUST 140 NOT reply with a modified IKE_AUTH response if the initiator did not 141 send a modified IKE_AUTH request. 143 A supporting responder that has been configured not to support this 144 extension to the protocol MUST behave as the same as if it didn't 145 support this extension. It MUST NOT advertise the capability with a 146 VID payload, and it SHOULD reply with an INVALID_SYNTAX Notify 147 payload if the client sends an IKE_AUTH request that is modified as 148 described in Section 5. 150 4. VID Payload 152 The VID payload is as described in [RFC4306] with a 16-octets data 153 field as follows: 155 73da4b423dd9f75563b15b9f918650fc 157 This value was obtained by hashing the string "Will do IKE_AUTH 158 without child SA payloads" using the MD5 algorithms. Note that this 159 is only an explanation, and the actual content of the VID data MUST 160 be the value above. 162 5. Modified IKE_AUTH Exchange 164 For brevity, only the EAP version of an AUTH exchange will be 165 presented here. The non-EAP version is very similar. The figures 166 below are based on appendix A.3 of [RFC4718]. 168 first request --> IDi, 169 [N(INITIAL_CONTACT)], 170 [[N(HTTP_CERT_LOOKUP_SUPPORTED)], CERTREQ+], 171 [IDr], 172 [CP(CFG_REQUEST)], 173 [V+] 175 first response <-- IDr, [CERT+], AUTH, 176 EAP, 177 [V+] 179 / --> EAP 180 repeat 1..N times | 181 \ <-- EAP 183 last request --> AUTH 185 last response <-- AUTH, 186 [CP(CFG_REPLY)], 187 [V+] 189 Note what is missing: 190 o The optional notifications: IPCOMP_SUPPORTED, USE_TRANSPORT_MODE, 191 ESP_TFC_PADDING_NOT_SUPPORTED, and NON_FIRST_FRAGMENTS_ALSO. 192 o The SA payload. 193 o The traffic selector payloads. 194 o Any notification, extension payload or VendorID that has to do 195 with child SA negotiation. 197 6. Security Considerations 199 TBA 201 7. IANA Considerations 203 There are no IANA considerations for this document. 205 8. References 206 8.1. Normative References 208 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 209 Requirement Levels", BCP 14, RFC 2119, March 1997. 211 [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", 212 RFC 4306, December 2005. 214 [RFC4718] Eronen, P. and P. Hoffman, "IKEv2 Clarifications and 215 Implementation Guidelines", RFC 4718, October 2006. 217 8.2. Informative References 219 [3GPP.33.820] 220 3GPP, "Security of H(e)NB", 3GPP TR 33.820 8.0.0, 221 March 2009. 223 [SecureBeacon] 224 Sheffer, Y. and Y. Nir, "Secure Beacon: Securely Detecting 225 a Trusted Network", draft-sheffer-ipsecme-secure-beacon 226 (work in progress), June 2009. 228 [extractors] 229 Rescorla, E., "Keying Material Exporters for Transport 230 Layer Security (TLS)", draft-ietf-tls-extractor (work in 231 progress), March 2009. 233 Authors' Addresses 235 Yoav Nir 236 Check Point Software Technologies Ltd. 237 5 Hasolelim st. 238 Tel Aviv 67897 239 Israel 241 Email: ynir@checkpoint.com 242 Hannes Tschofenig 243 Nokia Siemens Networks 244 Linnoitustie 6 245 Espoo 02600 246 Finland 248 Phone: +358 (50) 4871445 249 Email: Hannes.Tschofenig@gmx.net 250 URI: http://www.tschofenig.priv.at 252 Hui Deng 253 China Mobile 254 53A,Xibianmennei Ave. 255 Xuanwu District 256 Beijing 100053 257 China 259 Email: denghui02@gmail.com 261 Rajeshwar Singh Jenwar 262 Cisco Systems, Inc. 263 O'Shaugnessy Road 264 Bangalore, Karnataka 560025 265 India 267 Phone: +91 80 4103 3563 268 Email: rsj@cisco.com