Path Computation Element D. Dhody Internet-Draft Huawei Updates: 8253 (if approved) S. Turner Intended status: Standards Track sn3rd Expires: 8 May 2024 R. Housley Vigil Security 5 November 2023 Updates for PCEPS: TLS Connection Establishment Restrictions draft-ietf-pce-pceps-tls13-02 Abstract Section 3.4 of RFC 8253 specifies TLS connection establishment restrictions for PCEPS; PCEPS refers to usage of TLS to provide a secure transport for PCEP (Path Computation Element Communication Protocol). This document adds restrictions to specify what PCEPS implementations do if a PCEPS supports more than one version of the TLS protocol and to restrict the use of TLS 1.3’s early data. About This Document This note is to be removed before publishing as an RFC. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-ietf-pce-pceps-tls13/. Discussion of this document takes place on the Path Computation Element Working Group mailing list (mailto:pce@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/pce/. Subscribe at https://www.ietf.org/mailman/listinfo/pce/. Source for this draft and an issue tracker can be found at https://github.com/ietf-wg-pce/draft-ietf-pce-pceps-tls13. 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/. Dhody, et al. Expires 8 May 2024 [Page 1] Internet-Draft Updates for PCEPS November 2023 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 8 May 2024. Copyright Notice Copyright (c) 2023 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 3. TLS Connection Establishment Restrictions . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. Implementation Status . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 6 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction Section 3.4 of [RFC8253] specifies TLS connection establishment restrictions for PCEPS; PCEPS refers to usage of TLS to provide a secure transport for PCEP (Path Computation Element Communication Protocol) [RFC5440]. This document adds restrictions to specify what PCEPS implementations do if they support more than one version of the TLS protocol, e.g., TLS 1.2 [RFC5246] and TLS 1.3 [I-D.ietf-tls-rfc8446bis], and to restrict the use of TLS 1.3’s early data, which is also known as 0-RTT data. All other provisions set forth in [RFC8253] are unchanged, including connection initiation, message framing, connection closure, certificate validation, peer identity, and failure handling. Dhody, et al. Expires 8 May 2024 [Page 2] Internet-Draft Updates for PCEPS November 2023 | Editor's Note: The reference to [I-D.ietf-tls-rfc8446bis] could | be changed to RFC 8446 incase the progress of the bis draft is | slower than the progression of this document. 2. Conventions and Definitions 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. 3. TLS Connection Establishment Restrictions Section 3.4 of [RFC8253] Step 1 includes restrictions on PCEPS TLS connection establishment. This document adds the following restrictions: * Implementations that support multiple versions of the TLS protocol MUST prefer to negotiate the latest version of the TLS protocol. * PCEPS implementations that support TLS 1.3 or later MUST NOT use early data. NOTE: Early data (aka 0-RTT data) is a mechanism defined in TLS 1.3 [I-D.ietf-tls-rfc8446bis] that allows a client to send data ("early data") as part of the first flight of messages to a server. Note that TLS 1.3 can be used without early data as per Appendix F.5 of [I-D.ietf-tls-rfc8446bis]. In fact, early data is permitted by TLS 1.3 only when the client and server share a Pre- Shared Key (PSK), either obtained externally or via a previous handshake. The client uses the PSK to authenticate the server and to encrypt the early data. NOTE: As noted in Section 2.3 of [I-D.ietf-tls-rfc8446bis], the security properties for early data are weaker than those for subsequent TLS- protected data. In particular, early data is not forward secret, and there is no protection against the replay of early data between connections. Appendix E.5 of [I-D.ietf-tls-rfc8446bis] requires applications not use early data without a profile that defines its use. 4. Security Considerations The Security Considerations of PCEP [RFC5440], [RFC8231], [RFC8253], [RFC8281], and [RFC8283]; TLS 1.2 [RFC5246]; TLS 1.3 [I-D.ietf-tls-rfc8446bis], and; [RFC9325] apply here as well. Dhody, et al. Expires 8 May 2024 [Page 3] Internet-Draft Updates for PCEPS November 2023 The Path Computation Element (PCE) defined in [RFC4655] is an entity that is capable of computing a network path or route based on a network graph, and applying computational constraints. A Path Computation Client (PCC) may make requests to a PCE for paths to be computed. PCEP is the communication protocol between a PCC and PCE and is defined in [RFC5440]. Stateful PCE [RFC8231] specifies a set of extensions to PCEP to enable control of TE-LSPs by a PCE that retains the state of the LSPs provisioned in the network (a stateful PCE). [RFC8281] describes the setup, maintenance, and teardown of LSPs initiated by a stateful PCE without the need for local configuration on the PCC, thus allowing for a dynamic network that is centrally controlled. [RFC8283] introduces the architecture for PCE as a central controller TLS mutual authentication is used to ensure that only authorized users and systems are able to send and receive PCEP messages. To this end, neither the PCC nor the PCE should establish a PCEPS with TLS connection with an unknown, unexpected, or incorrectly identified peer; see Section 3.5 of [RFC5440]. If deployments make use of a trusted list of Certification Authority (CA) certificates [RFC5280], then the listed CAs should only issue certificates to parties that are authorized to access the PCE. Doing otherwise will allow certificates that were issued for other purposes to be inappropriately accepted by a PCE. 5. IANA Considerations There are no IANA considerations. 6. Implementation Status | Note to the RFC Editor - remove this section before | publication, as well as remove the reference to RFC 7942. This section records the status of known implementations of the protocol defined by this specification at the time of posting of this Internet-Draft, and is based on a proposal described in [RFC7942]. The description of implementations in this section is intended to assist the IETF in its decision processes in progressing drafts to RFCs. Please note that the listing of any individual implementation here does not imply endorsement by the IETF. Furthermore, no effort has been spent to verify the information presented here that was supplied by IETF contributors. This is not intended as, and must not be construed to be, a catalogue of available implementations or their features. Readers are advised to note that other implementations may exist. Dhody, et al. Expires 8 May 2024 [Page 4] Internet-Draft Updates for PCEPS November 2023 According to [RFC7942], "this will allow reviewers and working groups to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature. It is up to the individual working groups to use this information as they see fit". At the time of posting the -02 version of this document, there are no known implementations of this mechanism. 7. References 7.1. Normative References [I-D.ietf-tls-rfc8446bis] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", Work in Progress, Internet-Draft, draft- ietf-tls-rfc8446bis-09, 7 July 2023, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 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, . [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, DOI 10.17487/RFC5440, March 2009, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Dhody, et al. Expires 8 May 2024 [Page 5] Internet-Draft Updates for PCEPS November 2023 [RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody, "PCEPS: Usage of TLS to Provide a Secure Transport for the Path Computation Element Communication Protocol (PCEP)", RFC 8253, DOI 10.17487/RFC8253, October 2017, . [RFC9325] Sheffer, Y., Saint-Andre, P., and T. Fossati, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November 2022, . 7.2. Informative References [RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006, . [RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running Code: The Implementation Status Section", BCP 205, RFC 7942, DOI 10.17487/RFC7942, July 2016, . [RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path Computation Element Communication Protocol (PCEP) Extensions for Stateful PCE", RFC 8231, DOI 10.17487/RFC8231, September 2017, . [RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path Computation Element Communication Protocol (PCEP) Extensions for PCE-Initiated LSP Setup in a Stateful PCE Model", RFC 8281, DOI 10.17487/RFC8281, December 2017, . [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An Architecture for Use of PCE and the PCE Communication Protocol (PCEP) in a Network with Central Control", RFC 8283, DOI 10.17487/RFC8283, December 2017, . Acknowledgments We would like to thank Adrian Farrel, Stephane Litkowski, Cheng Li, and Andrew Stone for their review. Dhody, et al. Expires 8 May 2024 [Page 6] Internet-Draft Updates for PCEPS November 2023 Authors' Addresses Dhruv Dhody Huawei Email: dhruv.ietf@gmail.com Sean Turner sn3rd Email: sean@sn3rd.com Russ Housley Vigil Security, LLC 516 Dranesville Road Herndon, VA, 20170 United States of America Email: housley@vigilsec.com Dhody, et al. Expires 8 May 2024 [Page 7]