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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 (May 31, 2009) is 4737 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 152, 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 May 31, 2009 5 Expires: December 2, 2009 7 A Childless Initiation of the IKE SA 8 draft-nir-ike-nochild-01 10 Status of this Memo 12 This Internet-Draft is submitted to IETF in full conformance with the 13 provisions of BCP 78 and BCP 79. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 This Internet-Draft will expire on December 2, 2009. 33 Copyright Notice 35 Copyright (c) 2009 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents in effect on the date of 40 publication of this document (http://trustee.ietf.org/license-info). 41 Please review these documents carefully, as they describe your rights 42 and restrictions with respect to this document. 44 Abstract 46 This document describes an extension to the IKEv2 protocol that 47 allows an IKE SA to be created and authenticated without generating a 48 child SA. 50 Table of Contents 52 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 53 1.1. Conventions Used in This Document . . . . . . . . . . . . . 3 54 2. Usage Scenarios . . . . . . . . . . . . . . . . . . . . . . . . 3 55 3. Protocol Outline . . . . . . . . . . . . . . . . . . . . . . . 3 56 4. VID Payload . . . . . . . . . . . . . . . . . . . . . . . . . . 4 57 5. Modified IKE_AUTH Exchange . . . . . . . . . . . . . . . . . . 4 58 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 5 59 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5 60 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 61 8.1. Normative References . . . . . . . . . . . . . . . . . . . 5 62 8.2. Informative References . . . . . . . . . . . . . . . . . . 6 63 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 6 65 1. Introduction 67 IKEv2, as specified in [RFC4306] requires that in an IKE_AUTH 68 exchange, a child SA is created along with the IKE SA. This 69 requirement is sometimes inconvenient, as some implementations need 70 to use IKE for authentication only, while other implementations would 71 like to set up the IKE SA before there is any actual traffic to 72 protect. 74 An IKE SA without any child SA is not a fruitless endeavor. Even 75 without Child SAs, an IKE SA allows: 76 o Checking the liveness status of the peer via liveness checks. 77 o Quickly setting up child SAs without public key operations, and/or 78 without user interaction. 79 o Authentication of the peer. 81 1.1. Conventions Used in This Document 83 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 84 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 85 document are to be interpreted as described in [RFC2119]. 87 2. Usage Scenarios 89 Several scenarios motivated this proposal: 90 o Interactive remote access VPN: the user tells the client to 91 "connect", which may involve interactive authentication. There is 92 still no traffic, but some may come later. Since there is no 93 traffic, it is impossible for the gateway to know what selectors 94 to use (how to narrow down the client's proposal). 95 o Location aware security, as in [SecureBeacon]. The user is 96 roaming between trusted and untrusted networks. While in an 97 untrusted network, all traffic should be encrypted, but on the 98 trusted network, only the IKE SA needs to be maintained. 99 o A future extension may have IKE SAs used for generating keying 100 material for applications, without ever requiring child SAs. This 101 is similar to what [extractors] is doing in TLS. 103 In some of these cases it may be possible to create a dummy Child SA 104 and then remove it, but this creates undesirable side effects and 105 race conditions. Moreover, the IKE peer might see the deletion of 106 the Child SA as a reason to delete the IKE SA. 108 3. Protocol Outline 110 The decision of whether or not to support an IKE_AUTH exchage without 111 the piggy-backed child SA negotiation is ultimately up to the 112 reponsder. A supporting resonder MUST include the VID payload, 113 described in Section 4, within the IKE_INIT response. 115 A supporting initiator MAY send the modified IKE_AUTH request, 116 described in Section 5, if the VID payload was included in the 117 IKE_INIT response. The initiator MUST NOT send the modified IKE_AUTH 118 request if the VID was not present. 120 A supporting responder that advertised the VID payload in the 121 IKE_INIT response MUST process a modified IKE_AUTH request, and MUST 122 reply with a modified IKE_AUTH response. Such a responder MUST NOT 123 reply with a modified IKE_AUTH response if the initiator did not send 124 a modified IKE_AUTH request. 126 A supporting responder that has been configured not to support this 127 extension to the protocol MUST behave as the same as if it didn't 128 support this extension. It MUST NOT advertise the capability with a 129 VID payload, and it SHOULD reply with an INVALID_SYNTAX Notify 130 payload if the client sends an IKE_AUTH request that is modified as 131 described in Section 5. 133 4. VID Payload 135 The VID payload is as described in [RFC4306] with the data as 136 follows: 138 73da4b423dd9f75563b15b9f918650fc 140 This value was obtained by hashing the string "Will do IKE_AUTH 141 without child SA payloads" 143 5. Modified IKE_AUTH Exchange 145 For brevity, only the EAP version of an AUTH exchange will be 146 presented here. The non-EAP version is very similar. The figures 147 below are based on appendix A.3 of [RFC4718]. 149 first request --> IDi, 150 [N(INITIAL_CONTACT)], 151 [[N(HTTP_CERT_LOOKUP_SUPPORTED)], CERTREQ+], 152 [IDr], 153 [CP(CFG_REQUEST)], 154 [V+] 156 first response <-- IDr, [CERT+], AUTH, 157 EAP, 158 [V+] 160 / --> EAP 161 repeat 1..N times | 162 \ <-- EAP 164 last request --> AUTH 166 last response <-- AUTH, 167 [CP(CFG_REPLY)], 168 [V+] 170 Note what is missing: 171 o The optional notifications: IPCOMP_SUPPORTED, USE_TRANSPORT_MODE, 172 ESP_TFC_PADDING_NOT_SUPPORTED, and NON_FIRST_FRAGMENTS_ALSO. 173 o The SA payload. 174 o The traffic selector payloads. 175 o Any notification, extension payload or VendorID that has to do 176 with child SA negotiation. 178 6. Security Considerations 180 TBA 182 7. IANA Considerations 184 There are no IANA considerations for this document. 186 8. References 188 8.1. Normative References 190 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 191 Requirement Levels", BCP 14, RFC 2119, March 1997. 193 [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", 194 RFC 4306, December 2005. 196 [RFC4718] Eronen, P. and P. Hoffman, "IKEv2 Clarifications and 197 Implementation Guidelines", RFC 4718, October 2006. 199 8.2. Informative References 201 [SecureBeacon] 202 Sheffer, Y. and Y. Nir, "Secure Beacon: Securely Detecting 203 a Trusted Network", draft-sheffer-ipsec-secure-beacon 204 (work in progress), January 2008. 206 [extractors] 207 Rescorla, E., "Keying Material Exporters for Transport 208 Layer Security (TLS)", draft-ietf-tls-extractor (work in 209 progress), March 2009. 211 Author's Address 213 Yoav Nir 214 Check Point Software Technologies Ltd. 215 5 Hasolelim st. 216 Tel Aviv 67897 217 Israel 219 Email: ynir@checkpoint.com