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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 6480 == Outdated reference: A later version (-07) exists of draft-ietf-sidrops-rpki-rsc-06 Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group R. Bush 3 Internet-Draft Arrcus & Internet Initiative Japan 4 Intended status: Standards Track R. Housley 5 Expires: 6 October 2022 Vigil Security 6 4 April 2022 8 The I in RPKI does not stand for Identity 9 draft-ietf-sidrops-rpki-has-no-identity-05 11 Abstract 13 There is a false notion that Internet Number Resources (INRs) in the 14 RPKI can be associated with the real-world identity of the 'owner' of 15 an INR. This document attempts to put that notion to rest. 17 Requirements Language 19 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 20 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 21 "OPTIONAL" in this document are to be interpreted as described in BCP 22 14 [RFC2119] [RFC8174] when, and only when, they appear in all 23 capitals, as shown here. 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 6 October 2022. 42 Copyright Notice 44 Copyright (c) 2022 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 Revised BSD License text as 53 described in Section 4.e of the Trust Legal Provisions and are 54 provided without warranty as described in the Revised BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. The Bottom Line . . . . . . . . . . . . . . . . . . . . . . . 3 60 3. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 4. Security Considerations . . . . . . . . . . . . . . . . . . . 5 62 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 63 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 64 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 65 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 66 7.2. Informative References . . . . . . . . . . . . . . . . . 6 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 69 1. Introduction 71 The Resource Public Key Infrastructure (RPKI), see [RFC6480], 72 "Represents the allocation hierarchy of IP address space and 73 Autonomous System (AS) numbers," which are collectively known as 74 Internet Number Resources (INRs). Since initial deployment, the RPKI 75 has grown to include other similar resource and routing data, e.g. 76 Router Keying for BGPsec, [RFC8635]. 78 In security terms, the phrase "Public Key" implies there is also a 79 corresponding private key [RFC5280]. The RPKI's strong authority 80 over ownership of INRs has misled some people toward a desire to use 81 RPKI private keys to sign arbitrary documents attesting that the INR 82 'owner' of those resources has attested to the authenticity of the 83 document content. But in reality, the RPKI certificate is only an 84 authorization to speak for the explicitly identified INRs; it is 85 explicitly not intended for authentication of the 'owners' of the 86 INRs. This situation is emphasized in Section 2.1 of [RFC6480]. 88 It has been suggested that one could authenticate real-world business 89 transactions with the signatures of INR holders. E.g. Bill's Bait 90 and Sushi could use the private key attesting to ownership of their 91 AS in the RPKI to sign a Letter of Authorization (LOA) for some other 92 party to rack and stack hardware owned by BB&S. Unfortunately, while 93 this may be technically possible, it is neither appropriate nor 94 meaningful. 96 The I in RPKI actually stands for "Infrastructure," as in Resource 97 Public Key Infrastructure, not for "Identity". In fact, the RPKI 98 does not provide any association between INRs and the real world 99 holder(s) of those INRs. The RPKI provides authorization to make 100 assertions only regarding named IP address blocks, AS numbers, etc. 102 In short, avoid the desire to use RPKI certificates for any purpose 103 other than the verification of authorizations associated with the 104 delegation of INRs or attestations related to INRs. Instead, 105 recognize that these authorizations and attestations take place 106 irrespective of the identity of a RPKI private key holder. 108 2. The Bottom Line 110 The RPKI was designed and specified to sign certificates for use 111 within the RPKI itself and to generate Route Origin Authorizations 112 (ROAs), [RFC6480], for use in routing. Its design intentionally 113 precluded use for attesting to real-world identity as, among other 114 issues, it would expose the Certification Authority (CA) to 115 liability. 117 That the RPKI does not authenticate real-world identity is by design. 118 If it tried to do so, aside from the liability, it would end in a 119 world of complexity with no proof of termination, as X.400 learned. 121 Registries such as the Regional Internet Registries (RIRs) provide 122 INR to real-world identity mapping through whois and similar 123 services. They claim to be authoritative, at least for the INRs 124 which they allocate. 126 PKI operations MUST NOT be performed with RPKI certificates other 127 than exactly as described, and for the purposes described, in 128 [RFC6480]. 130 I.e., RPKI-based credentials of INRs MUST NOT be used to authenticate 131 real-world documents or transactions without some formal external 132 authentication of the INR and the authority for the actually 133 anonymous INR holder to authenticate the particular document or 134 transaction. 136 Given sufficient external, i.e. non-RPKI, verification of authority, 137 the use of RPKI-based credentials seems superfluous. 139 3. Discussion 141 The RPKI base document, [RFC6480], Section 2.1 says explicitly "An 142 important property of this PKI is that certificates do not attest to 143 the identity of the subject." 144 The Template for a Certification Practice Statement (CPS) for the 145 Resource PKI (RPKI) [RFC7382] Section 3.1, Naming, makes very clear 146 that "The Subject name in each certificate SHOULD NOT be meaningful;" 147 and goes on to do so at some length. 149 Normally, the INR holder does not hold the private key attesting to 150 their resources; the Certification Authority (CA) does. The INR 151 holder has a real-world business relationship with the CA for which 152 they have likely signed real-world documents. 154 As the INR owner does not have the keying material, they rely on the 155 CA, to which they presumably present credentials, to manipulate their 156 INRs. These credentials may be userid/password (with two factor 157 authentication one hopes), a hardware token, client browser 158 certificates, etc. 160 Hence schemes such as [I-D.ietf-sidrops-rpki-rta] and 161 [I-D.ietf-sidrops-rpki-rsc] must go to great lengths to extract the 162 supposedly relevant keys from the CA. 164 For some particular INR, say Bill's Bait and Sushi's Autonomous 165 System (AS) number, someone out on the net probably has the 166 credentials to the CA account in which BB&S's INRs are registered. 167 That could be the owner of BB&S, Roberto's Taco Stand, an IT vendor, 168 or the Government of Elbonia. One simply can not know. 170 In large organizations, INR management is often compartmentalized 171 with no authority over anything beyond dealing with INR registration. 172 The INR manager for Bill's Bait and Sushi is unlikely to be 173 authorized to conduct bank transactions for BB&S, or even to 174 authorize access to BB&S's servers in some colocation facility. 176 Then there is the temporal issue. The owner of that AS may be BB&S 177 today when some document was signed, and could be the Government of 178 Elbonia tomorrow. Or the resource could have been administratively 179 moved from one CA to another, likely requiring a change of keys. If 180 so, how does one determine if the signature on the real-world 181 document is still valid? 183 While Ghostbuster Records [RFC6493] may seem to identify real-world 184 entities, their semantic content is completely arbitrary, and does 185 not attest to INR ownership. They are merely clues for operational 186 support contact in case of technical RPKI problems. 188 Usually, before registering INRs, CAs require proof of INR ownership 189 via external documentation and authorities. It is somewhat droll 190 that the CPS Template, [RFC7382], does not mention any diligence the 191 CA must, or even might, conduct to assure the INRs are in fact owned 192 by a registrant. 194 That someone can provide 'proof of possession' of the private key 195 signing over a particular INR should not be taken to imply that they 196 are a valid legal representative of the organization in possession of 197 that INR. They could be just an INR administrative person. 199 Autonomous System Numbers do not identify real-world entities. They 200 are identifiers some network operators 'own' and are only used for 201 loop detection in routing. They have no inherent semantics other 202 than uniqueness. 204 4. Security Considerations 206 Attempts to use RPKI data to authenticate real-world documents or 207 other artifacts requiring identity are invalid and misleading. 209 When a document is signed with the private key associated with an 210 RPKI certificate, the signer is speaking for the INRs, the IP address 211 space and Autonomous System (AS) numbers, in the certificate. This 212 is not an identity; this is an authorization. In schemes such as 213 [I-D.ietf-sidrops-rpki-rta] and [I-D.ietf-sidrops-rpki-rsc] the 214 signed message further narrows this scope of INRs. The INRs in the 215 message are a subset of the INRs in the certificate. If the 216 signature is valid, the message content comes from a party that is 217 authorized to speak for that subset of INRs. 219 Control of INRs for an entity could be used to falsely authorize 220 transactions or documents for which the INR manager has no authority. 222 5. IANA Considerations 224 This document has no IANA Considerations. 226 6. Acknowledgments 228 The authors thank George Michaelson and Job Snijders for lively 229 discussion, Geoff Huston for some more formal text, Ties de Kock for 230 useful suggestions, and last but not least, Biff for the loan of 231 Bill's Bait and Sushi. 233 7. References 235 7.1. Normative References 237 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 238 Requirement Levels", BCP 14, RFC 2119, 239 DOI 10.17487/RFC2119, March 1997, 240 . 242 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 243 Housley, R., and W. Polk, "Internet X.509 Public Key 244 Infrastructure Certificate and Certificate Revocation List 245 (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, 246 . 248 [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support 249 Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, 250 February 2012, . 252 [RFC7382] Kent, S., Kong, D., and K. Seo, "Template for a 253 Certification Practice Statement (CPS) for the Resource 254 PKI (RPKI)", BCP 173, RFC 7382, DOI 10.17487/RFC7382, 255 April 2015, . 257 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 258 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 259 May 2017, . 261 [RFC8635] Bush, R., Turner, S., and K. Patel, "Router Keying for 262 BGPsec", RFC 8635, DOI 10.17487/RFC8635, August 2019, 263 . 265 7.2. Informative References 267 [I-D.ietf-sidrops-rpki-rsc] 268 Snijders, J., Harrison, T., and B. Maddison, "Resource 269 Public Key Infrastructure (RPKI) object profile for Signed 270 Checklist (RSC)", Work in Progress, Internet-Draft, draft- 271 ietf-sidrops-rpki-rsc-06, 12 February 2022, 272 . 275 [I-D.ietf-sidrops-rpki-rta] 276 Michaelson, G. G., Huston, G., Harrison, T., Bruijnzeels, 277 T., and M. Hoffmann, "A profile for Resource Tagged 278 Attestations (RTAs)", Work in Progress, Internet-Draft, 279 draft-ietf-sidrops-rpki-rta-00, 21 January 2021, 280 . 283 [RFC6493] Bush, R., "The Resource Public Key Infrastructure (RPKI) 284 Ghostbusters Record", RFC 6493, DOI 10.17487/RFC6493, 285 February 2012, . 287 Authors' Addresses 289 Randy Bush 290 Arrcus & Internet Initiative Japan 291 5147 Crystal Springs 292 Bainbridge Island, WA 98110 293 United States of America 294 Email: randy@psg.com 296 Russ Housley 297 Vigil Security, LLC 298 516 Dranesville Road 299 Herndon, VA, 20170 300 United States of America 301 Email: housley@vigilsec.com