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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references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 6480 == Outdated reference: A later version (-07) exists of draft-ietf-sidrops-rpki-rsc-05 Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--).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: 10 July 2022 Vigil Security 6 6 January 2022 8 The I in RPKI does not stand for Identity 9 draft-ietf-sidrops-rpki-has-no-identity-03 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 10 July 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 . . . . . . . . . . . . . . . . . . . . . . . 6 64 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 65 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 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). Though since, it has grown to 75 include other similar resource and routing data, e.g. Router Keying 76 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 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 their AS in the RPKI to sign a Letter of 91 Authorization (LOA) for some other party to rack and stack hardware 92 owned by BB&S. Unfortunately, this is not formally feasible. 94 The I in RPKI actually stands for "Infrastructure," as in Resource 95 Public Key Infrastructure, not for "Identity". In fact, the RPKI 96 does not provide any association between INRs and the real world 97 holder(s) of those INRs. The RPKI provides authorization to speak 98 for the named IP address blocks and AS numbers. 100 In short, avoid the desire to use RPKI certificates for any purpose 101 other than the verification of authorizations associated with the 102 delegation of INRs or attestations related to INRs. Instead, 103 recognize that these authorizations and attestations take place 104 irrespective of the identity of a RPKI private key holder. 106 2. The Bottom Line 108 The RPKI was designed and specified to sign certificates for use 109 within the RPKI itself and to generate Route Origin Authorizations 110 (ROAs), [RFC6480], for use in routing. Its design intentionally 111 precluded use for attesting to real world identity as, among other 112 issues, it would expose the Certification Authority (CA) to 113 liability. 115 That the RPKI does not authenticate real world identity is a feature 116 not a bug. If it tried to do so, aside from the liability, it would 117 end in a world of complexity with no proof of termination, as X.400 118 learned. 120 Registries such as the Regional Internet Resistries (RIRs) provide 121 INR to real world identity mapping through whois and similar 122 services. They claim to be authoritative, at least for the INRs 123 which they allocate. 125 RPKI-based credentials of INRs MUST NOT be used to authenticate real 126 world documents or transactions without some formal external 127 authentication of the INR and the authority for the actually 128 anonymous INR holder to authenticate the particular document or 129 transaction. 131 Note that, if there is sufficient external, i.e. non-RPKI, 132 verifcation of authority, then use of RPKI-based credentials seems 133 superfluous. 135 3. Discussion 137 The RPKI base document, [RFC6480], Section 2.1 says explicitly "An 138 important property of this PKI is that certificates do not attest to 139 the identity of the subject." 140 The Template for a Certification Practice Statement (CPS) for the 141 Resource PKI (RPKI) [RFC7382] Section 3.1, Naming, makes very clear 142 that "The Subject name in each certificate SHOULD NOT be meaningful;" 143 and goes on to do so at some length. 145 Normally, the INR holder does not hold the private key attesting to 146 their resources; the Certification Authority (CA) does. The INR 147 holder has a real world business relationship with the CA for which 148 they have likely signed real world documents. 150 As the INR owner does not have the keying material, they rely on the 151 CA, to which they presumably present credentials, to manipulate their 152 INRs. These credentials may be userid/password (with two factor 153 authentication one hopes), a hardware token, client browser 154 certificates, etc. 156 Hence schemes such as [I-D.ietf-sidrops-rpki-rta] and 157 [I-D.ietf-sidrops-rpki-rsc] must go to great lengths to extract the 158 supposedly relevant keys from the CA. 160 For some particular INR, say Bill's Bait and Sushi's Autonomous 161 System (AS) number, someone out on the net probably has the 162 credentials to the CA account in which BB&S's INRs are registered. 163 That could be the owner of BB&S, Roberto's Taco Stand, an IT vendor, 164 or the Government of Elbonia. One simply can not know. 166 In large organizations, INR management is often compartmentalized 167 with no authority over anything beyond dealing with INR registration. 168 The INR manager for Bill's Bait and Sushi is unlikely to be 169 authorized to conduct bank transactions for BB&S, or even to 170 authorize access to BB&S's servers in some colocation facility. 172 Then there is the temporal issue. The owner of that AS may be BB&S 173 today when some document was signed, and could be the Government of 174 Elbonia tomorrow. Or the resource could have been administratively 175 moved from one CA to another, likely requiring a change of keys. If 176 so, how does one determine if the signature on the real world 177 document is still valid? 179 While Ghostbuster Records [RFC6493] may seem to identify real world 180 entities, their semantic content is completely arbitrary, and does 181 not attest to INR ownership. They are merely clues for operational 182 support contact in case of technical RPKI problems. 184 Usually, before registering INRs, CAs require proof of INR ownership 185 via external documentation and authorities. It is somewhat droll 186 that the CPS Template, [RFC7382], does not mention any diligence the 187 CA must, or even might, conduct to assure the INRs are in fact owned 188 by a registrant. 190 That someone can provide 'proof of possession' of the private key 191 signing over a particular INR should not be taken to imply that they 192 are a valid legal representative of the organization in possession of 193 that INR. They could be just an INR administrative person. 195 Autonomous System Numbers do not identify real world entities. They 196 are identifiers some network operators 'own' and are only used for 197 loop detection in routing. They have no inherent semantics other 198 than uniqueness. 200 4. Security Considerations 202 Attempts to use RPKI data to authenticate real world documents or 203 other artifacts requiring identity are invalid and misleading. 205 When a document is signed with the private key associated with a RPKI 206 certificate, the signer is speaking for the INRs, the IP address 207 space and Autonomous System (AS) numbers, in the certificate. This 208 is not an identity; this is an authorization. In schemes such as 209 [I-D.ietf-sidrops-rpki-rta] and [I-D.ietf-sidrops-rpki-rsc] the 210 signed message further narrows this scope of INRs. The INRs in the 211 message are a subset of the INRs in the certificate. If the 212 signature is valid, the message content comes from a party that is 213 authorized to speak for that subset of INRs. 215 Control of INRs for an entity could be used to falsely authorize 216 transactions or documents for which the INR manager has no authority. 218 RPKI-based credentials of INRs MUST NOT be used to authenticate real 219 world documents or transactions without some formal external 220 authentication of the INR and the authority for the actually 221 anonymous INR holder to authenticate the particular document or 222 transaction. 224 5. IANA Considerations 226 This document has no IANA Considerations. 228 6. Acknowledgments 230 The authors thank George Michaelson and Job Snijders for lively 231 discussion, Geoff Huston for some more formal text, Ties de Kock for 232 useful suggestions, and last but not least, Biff for the loan of 233 Bill's Bait and Sushi. 235 7. References 237 7.1. Normative References 239 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 240 Requirement Levels", BCP 14, RFC 2119, 241 DOI 10.17487/RFC2119, March 1997, 242 . 244 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 245 Housley, R., and W. Polk, "Internet X.509 Public Key 246 Infrastructure Certificate and Certificate Revocation List 247 (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, 248 . 250 [RFC6480] Lepinski, M. and S. Kent, "An Infrastructure to Support 251 Secure Internet Routing", RFC 6480, DOI 10.17487/RFC6480, 252 February 2012, . 254 [RFC7382] Kent, S., Kong, D., and K. Seo, "Template for a 255 Certification Practice Statement (CPS) for the Resource 256 PKI (RPKI)", BCP 173, RFC 7382, DOI 10.17487/RFC7382, 257 April 2015, . 259 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 260 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 261 May 2017, . 263 [RFC8635] Bush, R., Turner, S., and K. Patel, "Router Keying for 264 BGPsec", RFC 8635, DOI 10.17487/RFC8635, August 2019, 265 . 267 7.2. Informative References 269 [I-D.ietf-sidrops-rpki-rsc] 270 Snijders, J., Harrison, T., and B. Maddison, "Resource 271 Public Key Infrastructure (RPKI) object profile for Signed 272 Checklist (RSC)", Work in Progress, Internet-Draft, draft- 273 ietf-sidrops-rpki-rsc-05, 11 August 2021, 274 . 277 [I-D.ietf-sidrops-rpki-rta] 278 Michaelson, G. G., Huston, G., Harrison, T., Bruijnzeels, 279 T., and M. Hoffmann, "A profile for Resource Tagged 280 Attestations (RTAs)", Work in Progress, Internet-Draft, 281 draft-ietf-sidrops-rpki-rta-00, 21 January 2021, 282 . 285 [RFC6493] Bush, R., "The Resource Public Key Infrastructure (RPKI) 286 Ghostbusters Record", RFC 6493, DOI 10.17487/RFC6493, 287 February 2012, . 289 Authors' Addresses 291 Randy Bush 292 Arrcus & Internet Initiative Japan 293 5147 Crystal Springs 294 Bainbridge Island, WA 98110 295 United States of America 297 Email: randy@psg.com 299 Russ Housley 300 Vigil Security, LLC 301 516 Dranesville Road 302 Herndon, VA, 20170 303 United States of America 305 Email: housley@vigilsec.com