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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network P. Wouters 3 Internet-Draft S. Prasad 4 Updates: 7296 (if approved) Red Hat 5 Intended status: Standards Track July 13, 2020 6 Expires: January 14, 2021 8 Labeled IPsec Traffic Selector support for IKEv2 9 draft-ietf-ipsecme-labeled-ipsec-03 11 Abstract 13 This document defines a new Traffic Selector (TS) Type for Internet 14 Key Exchange version 2 to add support for negotiating Mandatory 15 Access Control (MAC) security labels as a traffic selector of the 16 Security Policy Database (SPD). Security Labels for IPsec are also 17 known as "Labeled IPsec". The new TS type is TS_SECLABEL, which 18 consists of a variable length opaque field specifying the security 19 label. This document updates the IKEv2 TS negotiation specified in 20 RFC 7296 Section 2.9. 22 Status of This Memo 24 This Internet-Draft is submitted in full conformance with the 25 provisions of BCP 78 and BCP 79. 27 Internet-Drafts are working documents of the Internet Engineering 28 Task Force (IETF). Note that other groups may also distribute 29 working documents as Internet-Drafts. The list of current Internet- 30 Drafts is at https://datatracker.ietf.org/drafts/current/. 32 Internet-Drafts are draft documents valid for a maximum of six months 33 and may be updated, replaced, or obsoleted by other documents at any 34 time. It is inappropriate to use Internet-Drafts as reference 35 material or to cite them other than as "work in progress." 37 This Internet-Draft will expire on January 14, 2021. 39 Copyright Notice 41 Copyright (c) 2020 IETF Trust and the persons identified as the 42 document authors. All rights reserved. 44 This document is subject to BCP 78 and the IETF Trust's Legal 45 Provisions Relating to IETF Documents 46 (https://trustee.ietf.org/license-info) in effect on the date of 47 publication of this document. Please review these documents 48 carefully, as they describe your rights and restrictions with respect 49 to this document. Code Components extracted from this document must 50 include Simplified BSD License text as described in Section 4.e of 51 the Trust Legal Provisions and are provided without warranty as 52 described in the Simplified BSD License. 54 Table of Contents 56 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 57 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 58 1.2. Traffic Selector clarification . . . . . . . . . . . . . 3 59 1.3. Traffic Selector update . . . . . . . . . . . . . . . . . 3 60 2. TS_SECLABEL Traffic Selector Type . . . . . . . . . . . . . . 4 61 2.1. TS_SECLABEL payload format . . . . . . . . . . . . . . . 4 62 2.2. TS_SECLABEL properties . . . . . . . . . . . . . . . . . 4 63 3. Traffic Selector negotiation . . . . . . . . . . . . . . . . 5 64 3.1. Example TS negotiation . . . . . . . . . . . . . . . . . 6 65 3.2. Considerations for using multiple TS_TYPEs in a TS . . . 6 66 4. Security Considerations . . . . . . . . . . . . . . . . . . . 7 67 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 68 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 69 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 70 7.1. Normative References . . . . . . . . . . . . . . . . . . 7 71 7.2. Informative References . . . . . . . . . . . . . . . . . 8 72 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 74 1. Introduction 76 In computer security, Mandatory Access Control usually refers to 77 systems in which all subjects and objects are assigned a security 78 label. A security label is comprised of a set of security 79 attributes. The security labels along with a system authorization 80 policy determine access. Rules within the system authorization 81 policy determine whether the access will be granted based on the 82 security attributes of the subject and object. 84 Traditionally, security labels used by Multilevel Systems (MLS) are 85 comprised of a sensitivity level (or classification) field and a 86 compartment (or category) field, as defined in [FIPS188] and 87 [RFC5570]. As MAC systems evolved, other MAC models gained in 88 popularity. For example, SELinux, a Flux Advanced Security Kernel 89 (FLASK) implementation, has security labels represented as colon- 90 separated ASCII strings composed of values for identity, role, and 91 type. The security labels are often referred to as security 92 contexts. 94 Traffic Selector (TS) payloads specify the selection criteria for 95 packets that will be forwarded over the newly set up IPsec SA as 96 enforced by the Security Policy Database (SPD, see [RFC4301]). This 97 document updates the Traffic Selector negotiation specified in 98 Section 2.9 of [RFC7296]. 100 This document specifies a new Traffic Selector Type TS_SECLABEL for 101 IKEv2 that can be used to negotiate security labels as additional 102 selectors for the Security Policy Database (SPD) to further restrict 103 the type of traffic allowed to be sent and received over the IPsec 104 SA. 106 1.1. Requirements Language 108 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 109 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 110 "OPTIONAL" in this document are to be interpreted as described in BCP 111 14 [RFC2119] [RFC8174] when, and only when, they appear in all 112 captials, as shown here. 114 1.2. Traffic Selector clarification 116 The negotiation of Traffic Selectors is specified in Section 2.9 of 117 [RFC7296] where it defines two TS Types (TS_IPV4_ADDR_RANGE and 118 TS_IPV6_ADDR_RANGE). The Traffic Selector payload format is 119 specified in Section 3.13 of [RFC7296]. However, the term Traffic 120 Selector is used to denote the traffic selector payloads and 121 individual traffic selectors of that payload. Sometimes the exact 122 meaning can only be learned from context or if the item is written in 123 plural ("Traffic Selectors" or "TSs"). This section clarifies these 124 terms as follows: 126 A Traffic Selector (no acronym) is one selector for traffic of a 127 specific Traffic Selector Type (TS_TYPE). For example a Traffic 128 Selector of TS_TYPE TS_IPV4_ADDR_RANGE for UDP traffic in the IP 129 network 198.51.100.0/24 covering all ports, is denoted as (17, 0, 130 198.51.100.0-198.51.100.255) 132 A Traffic Selector payload (TS) is a set of one or more Traffic 133 Selectors of the same or different TS_TYPEs, but MUST include at 134 least one TS_TYPE of TS_IPV4_ADDR_RANGE or TS_IPV6_ADDR_RANGE. For 135 example, the above Traffic Selector by itself in a TS payload is 136 denotated as TS((17, 0, 198.51.100.0-198.51.100.255)) 138 1.3. Traffic Selector update 140 The negotiation of Traffic Selectors is specified in Section 2.9 of 141 [RFC7296] and states that the TSi/TSr payloads MUST contain at least 142 one Traffic Selector type. This document updates the text to mean 143 that the TSi/TSr payloads MUST contain at least one Traffic Selector 144 of type TS_IPV4_ADDR_RANGE or TS_IPV6_ADDR_RANGE, as other Traffic 145 Selector types can be defined that are complimentary to these Traffic 146 Selector Types and cannot be selected on their own without 147 TS_IPV4_ADDR_RANGE or TS_IPV6_ADDR_RANGE. The below defined 148 TS_SECLABEL Traffic Selector Type is an example of this. 150 2. TS_SECLABEL Traffic Selector Type 152 This document defines a new TS Type, TS_SECLABEL that contains a 153 single new opaque Security Label. 155 2.1. TS_SECLABEL payload format 157 1 2 3 158 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 1 159 +---------------+---------------+-------------------------------+ 160 | TS Type | Reserved | Selector Length | 161 +---------------+---------------+-------------------------------+ 162 | | 163 ~ Security Label* ~ 164 | | 165 +---------------------------------------------------------------+ 167 Figure 1: Labeled IPsec Traffic Selector 169 *Note: All fields other than TS Type and Selector Length depend on 170 the TS Type. The fields shown is for TS Type TS_SECLABEL, the 171 selector this document defines. 173 o TS Type (one octet) - Set to [TBD] for TS_SECLABEL, 175 o Selector Length (2 octets, unsigned integer) - Specifies the 176 length of this Traffic Selector substructure including the header. 178 o Security Label - An opaque byte stream of at least one octet. 180 2.2. TS_SECLABEL properties 182 The TS_SECLABEL Traffic Selector Type does not support narrowing or 183 wildcards. It MUST be used as an exact match value. 185 If the TS_SECLABEL is present in a TSi/TSr, at least one Traffic 186 Selector of type TS_IPV4_ADDR_RANGE or TS_IPV6_ADDR_RANGE MUST also 187 be present in that TSi/TSr. 189 The Security Label contents are opaque to the IKE implementation. 190 That is, the IKE implementation might not have any knowledge of the 191 meaning of this selector, other than as a type and opaque value to 192 pass to the SPD. 194 A zero length Security Label MUST NOT be used. If a received TS 195 payload contains a TS_TYPE of TS_SECLABEL with a zero length Security 196 Label, that specific Traffic Selector MUST be ignored. If no other 197 Traffic Selector of TS_TYPE TS_SECLABEL can be selected, a 198 TS_UNACCEPTABLE Error Notify message MUST be returned. A zero length 199 Security Label MUST NOT be interpreted as a wildcard security label. 201 If multiple Security Labels are allowed for a given IP protocol, 202 start and end address/port match, multiple TS_SECLABEL can be 203 included in a TS payload. 205 If the Security Label traffic selector is optional from a 206 configuration point of view, the initiator will have to choose which 207 TS payload to attempt first. If it includes the Security Label and 208 receives a TS_UNAVAILABLE, it can attempt a new Child SA negotiation 209 without that Security Label. 211 A responder that selected a TS with TS_SECLABEL MUST use the Security 212 Label for all selector operations on the resulting IPsec SA. It MUST 213 NOT select a TS_set with a TS_SECLABEL without using the specified 214 Security Label, even if it deems the Security Label optional, as the 215 initiator TS_set with TS_SECLABEL means the initiator mandates using 216 that Security Label. 218 3. Traffic Selector negotiation 220 This document updates the [RFC7296] specification as follows: 222 Each TS payload (TSi and TSr) MUST contain at least one TS_TYPE of 223 TS_IPV4_ADDR_RANGE or TS_IPV6_ADDR_RANGE. 225 Each TS payload (TSi or TSr) MAY contain one or more other TS_TYPEs, 226 such as TS_SECLABEL. 228 A responder MUST create its TS response by selecting one of each 229 TS_TYPE present in the offered TS by the initiator. If it cannot 230 select one of each TS_TYPE, it MUST return a TS_UNAVAILABLE Error 231 Notify payload. 233 If a specific TS_TYPE (other than TS_IPV4_ADDR_RANGE or 234 TS_IPV6_ADDR_RANGE which are mandatory) is deemed optional, the 235 initiator SHOULD first try to negotiate the Child SA with the TS 236 payload including the optional TS_TYPE. Upon receiving 237 TS_UNAVAILABLE, it SHOULD attempt a new Child SA negotiation using 238 the same TS but without the optional TS_TYPE. 240 Some TS_TYPE's support narrowing, where the responder is allowed to 241 select a subset of the original TS. Narrowing MUST NOT result in an 242 empty selector for that TS_TYPE. 244 3.1. Example TS negotiation 246 An initiator could send: 248 TSi = ((17,0,192.0.2.0-192.0.2.255), 249 (0,0,198.51.0-198.51.255), 250 TS_SECLABEL1, TS_SECLABEL2) 252 TSr = ((17,0,203.0.113.0-203.0.113.255), 253 (0,0,203.0.113.0-203.0.113.255), 254 TS_SECLABEL1, TS_SECLABEL2) 256 Figure 2: initiator TS payloads example 258 The responder could answer with the following example: 260 TSi = ((0,0,198.51.0-198.51.255), 261 TS_SECLABEL1) 263 TSr = (((0,0,203.0.113.0-203.0.113.255), 264 TS_SECLABEL1) 266 Figure 3: responder TS payloads example 268 3.2. Considerations for using multiple TS_TYPEs in a TS 270 It would be unlikely that the traffic for TSi and TSr would have a 271 different Security Label, but this specification does allow this to 272 be specified. If the initiator does not support this, and wants to 273 prevent the responder from picking different labels for the TSi / TSr 274 payloads, it should attempt a Child SA negotiation with only the 275 first Security Label first, and upon failure retry a new Child SA 276 negotiation with only the second Security Label. 278 If different IP ranges can only use different specific Security 279 Labels, than these should be negotiated in two different Child SA 280 negotiations. If in the example above, the initiator only allows 281 192.0.2.0/24 with TS_SECLABEL1, and 198.51.0/24 with TS_SECLABEL2, 282 than it MUST NOT combine these two ranges and security labels into 283 one Child SA negotiation. 285 Narrowing of Traffic Selectors currenrtly only applies only to 286 TS_IPV4_ADDR_RANGE and TS_IPV6_ADDR_RANGE and not to TS_SECLABEL as 287 the Security Label itself is not interpreted and cannot itself be 288 narrowed. It MUST be matched exactly. Rekey of an IPsec SA MUST 289 only use identical Traffic Selectors, which means the same TS Type 290 and selectors MUST be used. This guarantees that a Security Label 291 once negotiated, remains part of the IPsec SA after a rekey. 293 4. Security Considerations 295 It is assumed that the Security Label can be matched by the IKE 296 implementation to its own configured value, even if the IKE 297 implemention itself cannot interpret the Security Label value. 299 5. IANA Considerations 301 This document defines two new entries in the IKEv2 Traffic Selector 302 Types registry: 304 Value TS Type Reference 305 ----- --------------------------- ----------------- 306 TBD TS_SECLABEL [this document] 308 Figure 4 310 6. Acknowledgements 312 A large part of the introduction text was taken verbatim from 313 [draft-jml-ipsec-ikev2-security-label] whose authors are J Latten, D. 314 Quigley and J. Lu. 316 7. References 318 7.1. Normative References 320 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 321 Requirement Levels", BCP 14, RFC 2119, 322 DOI 10.17487/RFC2119, March 1997, 323 . 325 [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. 326 Kivinen, "Internet Key Exchange Protocol Version 2 327 (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October 328 2014, . 330 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 331 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 332 May 2017, . 334 7.2. Informative References 336 [draft-jml-ipsec-ikev2-security-label] 337 Latten, J., Quigley, D., and J. Lu, "Security Label 338 Extension to IKE", draft-wouters-edns-tcp-keeaplive (work 339 in progress), January 2011. 341 [FIPS188] NIST, "National Institute of Standards and Technology, 342 "Standard Security Label for Information Transfer"", 343 Federal Information Processing Standard (FIPS) Publication 344 188, September 1994. 346 [RFC4301] Kent, S. and K. Seo, "Security Architecture for the 347 Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, 348 December 2005, . 350 [RFC5570] StJohns, M., Atkinson, R., and G. Thomas, "Common 351 Architecture Label IPv6 Security Option (CALIPSO)", 352 RFC 5570, DOI 10.17487/RFC5570, July 2009, 353 . 355 Authors' Addresses 357 Paul Wouters 358 Red Hat 360 Email: pwouters@redhat.com 362 Sahana Prasad 363 Red Hat 365 Email: sahana@redhat.com