--- 1/draft-ietf-sidrops-https-tal-07.txt 2019-04-30 02:13:11.813181377 -0700 +++ 2/draft-ietf-sidrops-https-tal-08.txt 2019-04-30 02:13:11.841182087 -0700 @@ -1,127 +1,149 @@ Network Working Group G. Huston Internet-Draft APNIC Obsoletes: 7730 (if approved) S. Weiler Intended status: Standards Track W3C/MIT -Expires: September 5, 2019 G. Michaelson +Expires: November 1, 2019 G. Michaelson APNIC S. Kent Unaffiliated T. Bruijnzeels NLnet Labs - March 4, 2019 + April 30, 2019 Resource Public Key Infrastructure (RPKI) Trust Anchor Locator - draft-ietf-sidrops-https-tal-07 + draft-ietf-sidrops-https-tal-08 Abstract This document defines a Trust Anchor Locator (TAL) for the Resource Public Key Infrastructure (RPKI). TALs allow Relying Parties in the RPKI to download the current Trust Anchor (TA) CA certificate from one or more locations, and verify that the key of this self-signed certificate matches the key on the TAL. Thus, Relying Parties can be configured with TA keys, but allow these TAs to change the content of their CA certificate. In particular it allows TAs to change the set - of Internet Number Resources included in the RFC3779 extension of - their certificate. + of IP Address Delegations and/or Autonomous System Identifier + Delegations included in the RFC3779 extension of their certificate. This document obsoletes the previous definition of Trust Anchor - Locators in RFC 7730 by adding support for HTTPS URIs. + Locators in RFC 7730 by adding support for RFC3986 Uniform Resource + Identifiers (URIs) that use HTTPS as the scheme. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on September 5, 2019. + This Internet-Draft will expire on November 1, 2019. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 + 1.2. Changes from RFC7730 . . . . . . . . . . . . . . . . . . 3 2. Trust Anchor Locator . . . . . . . . . . . . . . . . . . . . 3 2.1. Trust Anchor Locator Motivation . . . . . . . . . . . . . 3 - 2.2. Trust Anchor Locator File Format . . . . . . . . . . . . 3 + 2.2. Trust Anchor Locator File Format . . . . . . . . . . . . 4 2.3. TAL and Trust Anchor Certificate Considerations . . . . . 4 - 2.4. Example . . . . . . . . . . . . . . . . . . . . . . . . . 5 + 2.4. Example . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Relying Party Use . . . . . . . . . . . . . . . . . . . . . . 6 - 4. HTTPS Considerations . . . . . . . . . . . . . . . . . . . . 7 - 5. Security Considerations . . . . . . . . . . . . . . . . . . . 7 + 4. URI Scheme Considerations . . . . . . . . . . . . . . . . . . 7 + 5. Security Considerations . . . . . . . . . . . . . . . . . . . 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 8 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 + 8.1. Normative References . . . . . . . . . . . . . . . . . . 9 8.2. Informative References . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction This document defines a Trust Anchor Locator (TAL) for the Resource Public Key Infrastructure (RPKI) [RFC6480]. This format may be used to distribute trust anchor material using a mix of out-of-band and online means. Procedures used by Relying Parties (RPs) to verify RPKI signed objects SHOULD support this format to facilitate interoperability between creators of trust anchor material and RPs. - This document obsoletes [RFC7730] by adding support for HTTPS URIs in - a TAL. + This document obsoletes [RFC7730] by adding support for HTTPS URIs + [RFC7230] in a TAL. 1.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. +1.2. Changes from RFC7730 + + The TAL format defined in this document differs from the definition + in [RFC7730] in that: + + o it allows for the use of the HTTPS scheme in URIs [RFC7230]; and + + o it allows for the inclusion of an optional comment section. + + Note that current Relying Parties may not support this new format + yet. Therefore it is RECOMMENDED that a Trust Anchor operator + maintains a [RFC7730] TAL file for a time as well until they are + satisfied that RP tooling has been updated. + 2. Trust Anchor Locator 2.1. Trust Anchor Locator Motivation This document does not propose a new format for trust anchor material. A trust anchor in the RPKI is represented by a self-signed X.509 Certification Authority (CA) certificate, a format commonly used in PKIs and widely supported by RP software. This document specifies a format for data used to retrieve and verify the authenticity of a trust anchor in a very simple fashion. That data is referred to as the TAL. The motivation for defining the TAL is to enable selected data in the - trust anchor to change, without needing to effect redistribution of - the trust anchor per se. In the RPKI, certificates contain - extensions that represent Internet Number Resources (INRs) [RFC3779]. + trust anchor to change, without needing to redistribute the trust + anchor per se. + + In the RPKI, certificates contain an RFC3779 extension, that can + contain a set of IP Address Delegations and/or Autonomous System + Identifier Delegations. In this document we refer to these + delegations as the Internet Number Resources (INR) contained in an + RPKI certificate. + The set of INRs associated with an entity acting as a trust anchor is likely to change over time. Thus, if one were to use the common PKI convention of distributing a trust anchor to RPs in a secure fashion, then this procedure would need to be repeated whenever the INR set for the entity acting as a trust anchor changed. By distributing the TAL (in a secure fashion), instead of distributing the trust anchor, this problem is avoided, i.e., the TAL is constant so long as the trust anchor's public key and its location do not change. The TAL is analogous to the TrustAnchorInfo data structure specified @@ -137,75 +159,72 @@ 2.2. Trust Anchor Locator File Format In this document we define a Trust Anchor URI as a URI that can be used to retrieved a current Trust Anchor certificate. This URI MUST be either an rsync URI [RFC5781], or an HTTPS URI [RFC7230]. The TAL is an ordered sequence of: 1. an optional comment section consisting of one or more lines each starting with the '#' character, followed by human readable - informational UTF-8 text, and ending with a line break, + informational UTF-8 text, conforming to the restrictions defined + in section 2 of [RFC5198], and ending with a line break, 2. a URI section, that is comprised of one or more ordered lines, each containing a Trust Anchor URI, and ending with a line break, 3. a line break, 4. a subjectPublicKeyInfo [RFC5280] in DER format [X.509], encoded in Base64 (see Section 4 of [RFC4648]). To avoid long lines, line breaks MAY be inserted into the Base64-encoded string. Note that line breaks in this file can use either "" or "". 2.3. TAL and Trust Anchor Certificate Considerations Each Trust Anchor URI in the TAL MUST reference a single object. It MUST NOT reference a directory or any other form of collection of - objects. - - The referenced object MUST be a self-signed CA certificate that - conforms to the RPKI certificate profile [RFC6487]. This certificate - is the trust anchor in certification path discovery [RFC4158] and - validation [RFC5280] [RFC3779]. + objects. The referenced object MUST be a self-signed CA certificate + that conforms to the RPKI certificate profile [RFC6487]. This + certificate is the trust anchor in certification path discovery + [RFC4158] and validation [RFC5280] [RFC3779]. - The validity interval of this trust anchor SHOULD reflect the - anticipated period of stability of the particular set of INRs that - are associated with the putative trust anchor. + The validity interval of this trust anchor is chosen such that the + "notBefore" time predates the moment that this certificate is + published, and the "notAfter" time is after the planned time of re- + issuance of this certificate. The INR extension(s) of this trust anchor MUST contain a non-empty set of number resources. It MUST NOT use the "inherit" form of the INR extension(s). The INR set described in this certificate is the set of number resources for which the issuing entity is offering itself as a putative trust anchor in the RPKI [RFC6480]. The public key used to verify the trust anchor MUST be the same as the subjectPublicKeyInfo in the CA certificate and in the TAL. - The trust anchor MUST contain a stable key. This key MUST NOT change - when the certificate is reissued due to changes in the INR - extension(s), when the certificate is renewed prior to expiration, or - for any reason other than a key change. + The trust anchor MUST contain a stable key which does not change when + the certificate is reissued due to changes in the INR extension(s), + when the certificate is renewed prior to expiration. Because the public key in the TAL and the trust anchor MUST be - stable, this motivates operation of that CA in an offline mode. - - Thus, the entity that issues the trust anchor SHOULD issue a - subordinate CA certificate that contains the same INRs (via the use - of the "inherit" option in the INR extensions of the subordinate - certificate). This allows the entity that issues the trust anchor to - keep the corresponding private key of this certificate offline, while - issuing all relevant child certificates under the immediate - subordinate CA. This measure also allows the Certificate Revocation - List (CRL) issued by that entity to be used to revoke the subordinate - CA certificate in the event of suspected key compromise of this - online operational key pair that is potentially more vulnerable. + stable, this motivates operation of that CA in an offline mode. In + that case a subordinate CA certificate containing the same INRs, or + in theory any sub-set of INRs, can be issued for online operations. + This allows the entity that issues the trust anchor to keep the + corresponding private key of this certificate offline, while issuing + all relevant child certificates under the immediate subordinate CA. + This measure also allows the Certificate Revocation List (CRL) issued + by that entity to be used to revoke the subordinate CA certificate in + the event of suspected key compromise of this online operational key + pair that is potentially more vulnerable. The trust anchor MUST be published at a stable URI. When the trust anchor is reissued for any reason, the replacement CA certificate MUST be accessible using the same URI. Because the trust anchor is a self-signed certificate, there is no corresponding CRL that can be used to revoke it, nor is there a manifest [RFC6486] that lists this certificate. If an entity wishes to withdraw a self-signed CA certificate as a @@ -275,33 +294,36 @@ o Selecting the Trust Anchor URI randomly from the available list o Creating a prioritized list of URIs based on RP-specific parameters, such as connection establishment delay If the connection to the preferred URI fails, or the retrieved CA certificate public key does not match the TAL public key, the RP SHOULD retrieve the CA certificate from the next URI, according to the local preference ranking of URIs. -4. HTTPS Considerations +4. URI Scheme Considerations - Note that a Man in the Middle (MITM) cannot produce a CA certificate - that would be considered valid according to the process described in - Section 3. However, a MITM attack can be performed to prevent the - Relying Party from learning about an updated CA certificate. Because - of this, Relying Parties MUST do TLS certificate and host name - validation when they fetch a CA certificate using an HTTPS URI on a - TAL. + Please note that the RSYNC protocol provides neither transport + security nor any means by which the Relying Party can validate that + they are connected to the proper host. There it is RECOMMENDED that + HTTPS is used as the preferred scheme. - Relying Party tools SHOULD log any TLS certificate or host name - validation issues found, so that an operator can investigate the - cause. + Note that, although a Man in the Middle (MITM) cannot produce a CA + certificate that would be considered valid according to the process + described in Section 3, this attack can prevent that the Relying + Party learns about an updated CA certificate. + + Relying Parties MUST do TLS certificate and host name validation when + they fetch a CA certificate using an HTTPS URI on a TAL. RPs SHOULD + log any TLS certificate or host name validation issues found, so that + an operator can investigate the cause. It is RECOMMENDED that Relying Parties and Repository Servers follow the Best Current Practices outlined in [RFC7525] on the use of HTTP over TLS (HTTPS) [RFC7230]. Relying Parties SHOULD do TLS certificate and host name validation using subjectAltName dNSName identities as described in [RFC6125]. The rules and guidelines defined in [RFC6125] apply here, with the following considerations: o Relying Parties and Repository Servers SHOULD support the DNS-ID identifier type. The DNS-ID identifier type SHOULD be present in @@ -367,20 +389,24 @@ [RFC3779] Lynn, C., Kent, S., and K. Seo, "X.509 Extensions for IP Addresses and AS Identifiers", RFC 3779, DOI 10.17487/RFC3779, June 2004, . [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, . + [RFC5198] Klensin, J. and M. Padlipsky, "Unicode Format for Network + Interchange", RFC 5198, DOI 10.17487/RFC5198, March 2008, + . + [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, . [RFC5781] Weiler, S., Ward, D., and R. Housley, "The rsync URI Scheme", RFC 5781, DOI 10.17487/RFC5781, February 2010, . @@ -413,22 +439,22 @@ [RFC7730] Huston, G., Weiler, S., Michaelson, G., and S. Kent, "Resource Public Key Infrastructure (RPKI) Trust Anchor Locator", RFC 7730, DOI 10.17487/RFC7730, January 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . - [X.509] TU-T Recommendation X.509, "The Directory: Public-key and - attribute certificate frameworks", October 2012. + [X.509] ITU-T, "The Directory: Public-key and attribute + certificate frameworks", October 2012. 8.2. Informative References [RFC4158] Cooper, M., Dzambasow, Y., Hesse, P., Joseph, S., and R. Nicholas, "Internet X.509 Public Key Infrastructure: Certification Path Building", RFC 4158, DOI 10.17487/RFC4158, September 2005, . [RFC5914] Housley, R., Ashmore, S., and C. Wallace, "Trust Anchor