BGP Provisioned IPsec Transport Mode Protected Tunnel Configuration
draft-hujun-idr-bgp-ipsec-transport-mode-00

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idr                                                                J. Hu
Internet-Draft                                                     Nokia
Intended status: Standards Track                        October 10, 2019
Expires: April 12, 2020

  BGP Provisioned IPsec Transport Mode Protected Tunnel Configuration
              draft-hujun-idr-bgp-ipsec-transport-mode-00

Abstract

   This document defines a method of using BGP to advertise IPsec
   transport mode protected tunnel (like GRE tunnel with IPsec transport
   mode protection) configuration along with NLRI, based on
   [I-D.ietf-idr-tunnel-encaps] and [I-D.hujun-idr-bgp-ipsec].

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
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   This Internet-Draft will expire on April 12, 2020.

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   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
     1.2.  IPsec Transport Protected sub-TLV . . . . . . . . . . . .   3
   2.  Semantics and Operation . . . . . . . . . . . . . . . . . . .   3
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   5.  Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   [I-D.hujun-idr-bgp-ipsec] defines a method of using BGP to advertise
   configuration for IPsec tunnel with ESP tunnel mode, however there
   are other use cases require of using IPsec/ESP transport mode with
   other types of IP tunnel, like GRE tunnel, as defined in [RFC4301]
   and [RFC4303].  Figure 2 shows an example of IPv4 GRE tunnel packet
   with ESP transport mode protection.  This document defines a method
   of using BGP to advertise configuration for these use cases.

                ----------------------------------------------------
                |IPv4 header  | ESP | GRE | Payload |   ESP   | ESP|
                |(any options)| Hdr | Hdr | Packet  | Trailer | ICV|
                ----------------------------------------------------
                                          |<-- encryption --->|
                                    |<-------- integrity ---->|

      Figure 1: IPv4 GRE tunnel packet with ESP transport protection

   The method follows same principle as [I-D.hujun-idr-bgp-ipsec], keep
   changes to BGP minimal and not changing IKEv2/IPsec; however the
   IPsec transport mode protected IP tunnel is not a tunnel stack or
   nested tunnels, IPsec transport mode protection doesn't add extra IP
   header.

   The requirement of using IPsec transport mode is signaled by
   including a sub-TLV: IPsec transport protected, in a BGP tunnel
   encapsulation TLV.

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

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   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

1.2.  IPsec Transport Protected sub-TLV

   This sub-TLV represents using IPsec transport mode protection for the
   tunnel specified by parent tunnel encapsulation TLV, its value is a
   IPsec configuration tag as defined in [I-D.hujun-idr-bgp-ipsec].

                          +--------------------------------------+
                          |   IPsec Configuration tag (4 octets) |
                          +--------------------------------------+

                     Figure 2: IPsec Configuration Tag

   For a given tunnel encapsulation TLV, IPsec configuration tag sub-TLV
   MUST appear only one time.

2.  Semantics and Operation

   Except for what this document explicitly specifies, the semantics and
   operation of tunnel encapsulation TLV with IPsec Transport Protected
   sub-TLV are same as defined in [I-D.ietf-idr-tunnel-encaps] and
   [I-D.hujun-idr-bgp-ipsec].

   IPsec Transport Protected sub-TLV MAY be included in any type of IP
   tunnel TLV specified in [I-D.ietf-idr-tunnel-encaps]; it MUST be
   ignored when included in a IPsec tunnel TLV.

   The inclusion of IPsec Transport Protected TLV and its value is
   determined by local policy.

   Following are the rules of operations:

   1.  All routers are pre-provisioned with Mapping between IPsec
       configuration tag value and IPsec configurations include
       authentication method/credentials

   2.  If a given NLRI needs a specific tunnel encapsulation with IPsec
       transport mode protection, then advertising router need to
       include an IPsec Transport Protected sub-TLV with required
       configuration tag, in the corresponding tunnel encapsulation TLV/
       attribute, along with the NLRI in BGP UPDATE U;

   3.  When a router need to forward a packet along a path is determined
       by a BGP UPDATE which has a tunnel encapsulation attribute that
       contains one or more tunnel TLV, router selects a tunnel TLV
       based on Semantics defined in [I-D.ietf-idr-tunnel-encaps], if

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       the selected tunnel TLV contains IPsec Transport Protected sub-
       TLV, then the router use first feasible CHILD_SA for IP tunnel
       packet encryption, a CHILD SA is considered as feasible when it
       meets all following conditions:

       *  it is ESP transport mode

       *  its private and public routing instance is same as routing
          instance in which the packet to be forwarded

       *  its peer tunnel address is same as indicated by Remote
          Endpoint sub-TLV

       *  the source and destination address of the packet to be
          forwarded falls in the range of CHILD SA's traffic selector

       *  its transform and other configuration maps to the tag
          indicated in the IPsec configuration tag sub-TLV

   4.  If router can't find such CHILD SA, then it will use IKEv2 to
       create one with following IPsec configuration:

       *  ESP transport mode

       *  private and public routing instance is the routing instance in
          which the packet to be forwarded

       *  peer tunnel address is specified by Remote Endpoint sub-TLV

       *  local traffic selector:

          +  address range: local tunnel endpoint address

          +  protocol: tag mapped configuration

          +  port range: tag mapped configuration

       *  remote traffic selector:

          +  address range: address in Remote Endpoint sub-TLV of
             selected tunnel encapsulation TLV

          +  protocol: tag mapped configuration

          +  port range: tag mapped configuration

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       *  other configurations come from mapping of the configuration
          tag in IPsec Transport Protected sub-TLV of selected tunnel
          encapsulation TLV

3.  IANA Considerations

   This document will request new values in IANA "BGP Tunnel
   Encapsulation Attribute Sub-TLVs" registry for IPsec Transport
   Protected sub-TLV.

4.  Security Considerations

   IKEv2 is used to create IPsec tunnel, which ensures following:

   o  Traffic protection keys are generated dynamically during IKEv2
      negotiation, only known by participating peer of the IPsec tunnel;
      there is no central node to manage and distribute all keys.

   o  IKEv2 rekey mechanism refresh keys regularly; PFS(Perfect Forward
      Secrecy) provides additional protection;

   o  Secure authentication mechanism that only allow authenticated peer
      to create tunnel

   o  Traffic Selector guarantee that only agreed traffic is allowed to
      be forwarded within the IPsec tunnel;

   o  Using a separate, dedicate protocol(IKEv2) for key management/
      authentication ensure they are not tied to BGP, all existing and
      future IKEv2 features could be used without changing BGP;

   There is concern that malicious party might manipulate IPsec tunnel
   encapsulation attribute to divert traffic, however this risk could be
   mitigated by IKEv2 mutual authentication.

   BGP route filter include outbound route filter [RFC5291], Origin
   Validation [RFC6811] and BGPSec [RFC8205] could be used to further
   secure BGP UPDATE message.

   IKEv2 cookie [RFC7296] and varies mechanisms defined including client
   puzzle defined in [RFC8019] could be used to protect IKEv2 from
   Distributed Denial-of-Service Attacks.

   Follow latest IETF ESP/IKEv2 implementation requirement and guidance
   ([RFC8221] and [RFC8247] at time of writing) to make sure always
   using secure and up-to-date cryptographic algorithms;

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5.  Change Log

   o  v00 Sep 29, 2019: initial draft

6.  References

6.1.  Normative References

   [I-D.hujun-idr-bgp-ipsec]
              Hu, J., "BGP Provisioned IPsec Tunnel Configuration",
              draft-hujun-idr-bgp-ipsec-01 (work in progress), September
              2019.

   [I-D.ietf-idr-tunnel-encaps]
              Patel, K., Velde, G., and S. Ramachandra, "The BGP Tunnel
              Encapsulation Attribute", draft-ietf-idr-tunnel-encaps-14
              (work in progress), September 2019.

   [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/info/rfc2119>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, DOI 10.17487/RFC4303, December 2005,
              <https://www.rfc-editor.org/info/rfc4303>.

   [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/info/rfc8174>.

6.2.  Informative References

   [RFC5291]  Chen, E. and Y. Rekhter, "Outbound Route Filtering
              Capability for BGP-4", RFC 5291, DOI 10.17487/RFC5291,
              August 2008, <https://www.rfc-editor.org/info/rfc5291>.

   [RFC6811]  Mohapatra, P., Scudder, J., Ward, D., Bush, R., and R.
              Austein, "BGP Prefix Origin Validation", RFC 6811,
              DOI 10.17487/RFC6811, January 2013,
              <https://www.rfc-editor.org/info/rfc6811>.

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   [RFC7296]  Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
              Kivinen, "Internet Key Exchange Protocol Version 2
              (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
              2014, <https://www.rfc-editor.org/info/rfc7296>.

   [RFC8019]  Nir, Y. and V. Smyslov, "Protecting Internet Key Exchange
              Protocol Version 2 (IKEv2) Implementations from
              Distributed Denial-of-Service Attacks", RFC 8019,
              DOI 10.17487/RFC8019, November 2016,
              <https://www.rfc-editor.org/info/rfc8019>.

   [RFC8205]  Lepinski, M., Ed. and K. Sriram, Ed., "BGPsec Protocol
              Specification", RFC 8205, DOI 10.17487/RFC8205, September
              2017, <https://www.rfc-editor.org/info/rfc8205>.

   [RFC8221]  Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T.
              Kivinen, "Cryptographic Algorithm Implementation
              Requirements and Usage Guidance for Encapsulating Security
              Payload (ESP) and Authentication Header (AH)", RFC 8221,
              DOI 10.17487/RFC8221, October 2017,
              <https://www.rfc-editor.org/info/rfc8221>.

   [RFC8247]  Nir, Y., Kivinen, T., Wouters, P., and D. Migault,
              "Algorithm Implementation Requirements and Usage Guidance
              for the Internet Key Exchange Protocol Version 2 (IKEv2)",
              RFC 8247, DOI 10.17487/RFC8247, September 2017,
              <https://www.rfc-editor.org/info/rfc8247>.

Author's Address

   Hu Jun
   Nokia
   777 East Middlefield Road
   Mountain View  CA 95148
   United States

   Email: jun.hu@nokia.com

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