268 lines
10 KiB
XML
268 lines
10 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!DOCTYPE rfc SYSTEM "rfc2629.dtd">
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<?rfc comments="yes"?>
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<?rfc compact="yes"?>
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<?rfc subcompact="no"?>
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<?rfc inline="yes"?>
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<?rfc sortrefs="yes"?>
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<?rfc symrefs="yes"?>
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<?rfc toc="yes"?>
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<?rfc tocdepth="6"?>
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<?rfc tocindent="yes"?>
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<?rfc tocompact="yes"?>
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<rfc category="std" consensus="true" docName="draft-ietf-sidrops-rpki-has-no-identity-01" ipr="trust200902">
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<front>
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<title>The I in RPKI does not stand for Identity</title>
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<author fullname="Randy Bush" initials="R." surname="Bush">
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<organization>Arrcus & Internet Initiative Japan</organization>
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<address>
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<postal>
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<street>5147 Crystal Springs</street>
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<city>Bainbridge Island</city>
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<region>WA</region>
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<code>98110</code>
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<country>US</country>
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</postal>
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<email>randy@psg.com</email>
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</address>
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</author>
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<author initials="R." surname="Housley" fullname="Russ Housley">
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<organization abbrev="Vigil Security">Vigil Security, LLC</organization>
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<address>
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<postal>
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<street>516 Dranesville Road</street>
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<city>Herndon, VA</city>
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<code>20170</code>
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<country>US</country>
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</postal>
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<email>housley@vigilsec.com</email>
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</address>
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</author>
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<date />
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<abstract>
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<t>There is a false notion that Internet Number Resources (INRs) in
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the RPKI can be associated with the real world identity of the 'owner'
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of an INR. This document attempts to put that notion to rest.</t>
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</abstract>
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<note title="Requirements Language">
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<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
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NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED",
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"MAY", and "OPTIONAL" in this document are to be interpreted as
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described in BCP 14 <xref target="RFC2119"/> <xref
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target="RFC8174"/> when, and only when, they appear in all capitals,
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as shown here.</t>
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</note>
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</front>
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<middle>
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<section anchor="intro" title="Introduction">
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<t>The Resource Public Key Infrastructure (RPKI), see <xref
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target="RFC6480"/>, "represents the allocation hierarchy of IP
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address space and Autonomous System (AS) numbers." Though since, it
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has grown to include other similar resource and routing data, e.g.
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Router Keying for BGPsec, <xref target="RFC8635"/>.</t>
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<t>In security terms the phrase "Public Key" implies there are also
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private keys, a la <xref target="RFC5280"/>. And, as the RPKI has
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strong authority over ownership of Internet Number Resources (INRs),
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there is a desire to use the private keys to sign arbitrary
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documents to attest that the 'owner' of those resources has attested
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to the authenticity of those documents. But in reality, it is an
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authorization to speak for the named IP address blocks and AS
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numbers themselves, not their unidentifiable owners.</t>
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<t>It has been suggested that one could authenticate real world
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business transactions with the signatures of INR holders. E.g.
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Bill's Bait and Sushi could use their AS in the RPKI to sign a
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Letter of Authorization (LOA) for some other party to rack and stack
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hardware owned by BB&S. Unfortunately, this is not formally
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feasible.</t>
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<t>The I in RPKI actually stands for "Infrastructure," as in
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Resource Public Key Infrastructure, not for "Identity". In fact,
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the RPKI does not provide any association between INRs and the real
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world holder(s) of those INRs. The RPKI provides authorization to
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speak for the named IP address blocks and AS numbers.</t>
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</section>
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<section anchor="bottom" title="The Bottom Line">
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<t>The RPKI was designed and specified to sign certificates for use
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within the RPKI itself and to generate Route Origin Authorizations
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(ROAs), <xref target="RFC6480"/>, for use in routing. Its design
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intentionally precluded use for attesting to real world identity as,
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among other issues, it would expose the Certification Authority (CA)
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to liability.</t>
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<t>That the RPKI does not authenticate real world identity is a
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feature not a bug. If it tried to do so, aside from the liability,
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it would end in a world of complexity with no proof of termination,
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as X.400 learned.</t>
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<t>Registries such as the Regional Internet Resistries (RIRs)
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provide INR to real world identity mapping through whois and similar
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services. They claim to be authoritative, at least for the INRs
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which they allocate.</t>
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<t>RPKI-based credentials of INRs MUST NOT be used to authenticate
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real world documents or transactions without some formal external
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authentication of the INR and the authority for the actually
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anonymous INR holder to authenticate the particular document or
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transaction.</t>
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<t>Note that, if there is sufficient external, i.e. non-RPKI,
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verifcation of authority, then use of RPKI-based credentials seems
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superfluous.</t>
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</section>
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<section anchor="discuss" title="Discussion">
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<t>The RPKI base document, <xref target="RFC6480"/>, Section 2.1
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says explicitly "An important property of this PKI is that
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certificates do not attest to the identity of the subject."</t>
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<t>The Template for a Certification Practice Statement (CPS) for the
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Resource PKI (RPKI) <xref target="RFC7382"/> Section 3.1, Naming,
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makes very clear that "The Subject name in each certificate SHOULD
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NOT be meaningful;" and goes on to do so at some length.</t>
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<t>Normally, the INR holder does not hold the private key attesting
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to their resources; the Certification Authority (CA) does. The INR
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holder has a real world business relationship with the CA for which
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they have likely signed real world documents.</t>
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<t>As the INR owner does not have the keying material, they rely on
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the CA, to which they presumably present credentials, to manipulate
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their INRs. These credentials may be userid/password (with two
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factor authentication one hopes), a hardware token, client browser
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certificates, etc.</t>
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<t>Hence schemes such as <xref target="I-D.ietf-sidrops-rpki-rta"/>
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and <xref target="I-D.ietf-sidrops-rpki-rsc"/> must go to great
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lengths to extract the supposedly relevant keys from the CA.</t>
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<t>For some particular INR, say Bill's Bait and Sushi's Autonomous
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System (AS) number, someone out on the net probably has the
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credentials to the CA account in which BB&S's INRs are
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registered. That could be the owner of BB&S, Roberto's Taco
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Stand, an IT vendor, or the Government of Elbonia. One simply can
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not know.</t>
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<t>In large organizations, INR management is often compartmentalized
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with no authority over anything beyond dealing with INR
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registration. The INR manager for Bill's Bait and Sushi is unlikely
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to be authorized to conduct bank transactions for BB&S, or even
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to authorize access to BB&S's servers in some colocation
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facility.</t>
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<t>Then there is the temporal issue. The owner of that AS may be
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BB&S today when some document was signed, and could be the
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Government of Elbonia tomorrow. Or the resource could have been
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administratively moved from one CA to another, likely requiring a
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change of keys. If so, how does one determine if the signature on
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the real world document is still valid?</t>
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<t>While Ghostbuster Records <xref target="RFC6493"/> may seem to
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identify real world entities, their semantic content is completely
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arbitrary, and does not attest to INR ownership. They are merely
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clues for operational support contact in case of technical RPKI
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problems.</t>
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<t>Usually, before registering INRs, CAs require proof of INR
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ownership via external documentation and authorities. It is
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somewhat droll that the CPS Template, <xref target="RFC7382"/>, does
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not mention any diligence the CA must, or even might, conduct to
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assure the INRs are in fact owned by a registrant.</t>
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<t>Autonomous System Numbers do not identify real world entities.
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They are identifiers some network operators 'own' and are only used
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for loop detection in routing. They have no inherent semantics other
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than uniqueness.</t>
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</section>
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<section anchor="security" title="Security Considerations">
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<t>Attempts to use RPKI data to authenticate real world documents or
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other artifacts requiring identity are invalid and misleading.</t>
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<t>When a document is signed with the private key associated with a
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RPKI certificate, the signer is speaking for the INRs, the IP
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address space and Autonomous System (AS) numbers, in the
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certificate. This is not an identity; this is an authorization. In
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schemes such as <xref target="I-D.ietf-sidrops-rpki-rta"/> and <xref
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target="I-D.ietf-sidrops-rpki-rsc"/> the signed message further
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narrows this scope of INRs. The INRs in the message are a subset of
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the INRs in the certificate. If the signature is valid, the message
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content comes from a party that is authorized to speak for that
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subset of INRs.</t>
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<t>Control of INRs for an entity could be used to falsely authorize
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transactions or documents for which the INR manager has no
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authority.</t>
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<t>RPKI-based credentials of INRs MUST NOT be used to authenticate
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real world documents or transactions without some formal external
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authentication of the INR and the authority for the actually
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anonymous INR holder to authenticate the particular document or
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transaction.</t>
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</section>
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<section anchor="iana" title="IANA Considerations">
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<t>This document has no IANA Considerations.</t>
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<!--
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<t>Note to RFC Editor: this section may be replaced on publication
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as an RFC.</t>
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-->
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</section>
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<section anchor="acks" title="Acknowledgments">
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<t>The authors thank George Michaelson and Job Snijders for lively
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discussion; and last but not least, Biff for the loan of Bill's Bait
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and Sushi.</t>
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</section>
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</middle>
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<back>
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<references title="Normative References">
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<?rfc include="reference.RFC.2119.xml"?>
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<?rfc include="reference.RFC.5280.xml"?>
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<?rfc include="reference.RFC.6480.xml"?>
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<?rfc include="reference.RFC.7382.xml"?>
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<?rfc include="reference.RFC.8174.xml"?>
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<?rfc include="reference.RFC.8635.xml"?>
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</references>
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<references title="Informative References">
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<?rfc include="reference.RFC.6493.xml"?>
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<?rfc include="reference.I-D.ietf-sidrops-rpki-rsc.xml"?>
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<?rfc include="reference.I-D.ietf-sidrops-rpki-rta.xml"?>
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</references>
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</back>
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</rfc>
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