Updates for PCEPS: TLS Connection Establishment Restrictions
draft-ietf-pce-pceps-tls13-02

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/.

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   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.

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   Please review these documents carefully, as they describe your rights
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   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.

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      |  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.

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   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.

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   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,
              <https://datatracker.ietf.org/doc/html/draft-ietf-tls-
              rfc8446bis-09>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/rfc/rfc2119>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/rfc/rfc5246>.

   [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,
              <https://www.rfc-editor.org/rfc/rfc5280>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <https://www.rfc-editor.org/rfc/rfc5440>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.

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   [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,
              <https://www.rfc-editor.org/rfc/rfc8253>.

   [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, <https://www.rfc-editor.org/rfc/rfc9325>.

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,
              <https://www.rfc-editor.org/rfc/rfc4655>.

   [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,
              <https://www.rfc-editor.org/rfc/rfc7942>.

   [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,
              <https://www.rfc-editor.org/rfc/rfc8231>.

   [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,
              <https://www.rfc-editor.org/rfc/rfc8281>.

   [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,
              <https://www.rfc-editor.org/rfc/rfc8283>.

Acknowledgments

   We would like to thank Adrian Farrel, Stephane Litkowski, Cheng Li,
   and Andrew Stone for their review.

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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

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