Internet DRAFT - draft-wirtgen-bgp-tls
draft-wirtgen-bgp-tls
IDR T. Wirtgen
Internet-Draft O. Bonaventure
Intended status: Experimental UCLouvain & WELRI
Expires: 25 April 2024 23 October 2023
BGP over TLS/TCP
draft-wirtgen-bgp-tls-00
Abstract
This document specifies the utilization of TCP/TLS to support BGP.
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-wirtgen-bgp-tls/.
Discussion of this document takes place on the IDR Working Group
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Source for this draft and an issue tracker can be found at
https://github.com/obonaventure/draft-bgp-tls.
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 25 April 2024.
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Copyright Notice
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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/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. Summary of operation . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 4
Change log . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
References . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Normative References . . . . . . . . . . . . . . . . . . . . . 5
Informative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The Border Gateway Protocol (BGP) [RFC4271] relies on the TCP
protocol to establish BGP sessions between routers. A recent draft
[I-D.draft-retana-idr-bgp-quic] has proposed to replace TCP with the
QUIC protocol [RFC9000]. QUIC brings many features compared to TCP
including security, the support of multiple streams or datagrams.
From a security viewpoint, an important benefit of QUIC compared to
TCP is that QUIC by design prevents injection attacks that are
possible when TCP is used by BGP [RFC4272]. Several techniques can
be used by BGP routers to counter this attacks [RFC5082] [RFC5925].
TCP-AO [RFC5925] authenticates the packets exchanged over a BGP
session provides similar features as QUIC. However, it is
notoriously difficult to configure the keys used to protect BGP
sessions.
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The widespread deployment of TLS [RFC8446] combined with the
possibility of deriving TCP-AO keys from the TLS handshake
[I-D.draft-piraux-tcp-ao-tls] creates an interest in using TLS to
secure BGP sessions. This document describes how BGP can operate
over TCP/TLS.
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.
This document uses network byte order (that is, big endian) values.
Fields are placed starting from the high-order bits of each byte.
3. Summary of operation
A BGP over TLS/TCP session is established in two phases:
* establish a transport layer connection using TCP
* establish a TLS session over the TCP connection
The TCP connection SHOULD be established on port TBD1.
During the establishment of the TLS session, the router that
initiates the connection MUST use the "botls" token in the
Application Layer Protocol Negotiation (ALPN) extension [RFC7301].
The support for other ALPN MUST NOT be proposed during the TLS
handshake.
Once the TLS handshake is established and finished, the BGP session
is initiated as defined in [RFC4271] and the protocol operates in the
same way as a classic BGP over TCP session. The difference is that
the BGP session is now encrypted and authenticated using the TLS
layer. As in [I-D.draft-retana-idr-bgp-quic], the TLS authentication
parameters used for this connection are out of the scope of this
draft.
4. Security Considerations
This document improves the security of BGP sessions since the
information exchanged over the session is now protected by using TLS.
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If TLS encounters a payload injection attack, it will generate an
alert that immediately closes the TLS session. The BGP router SHOULD
then attempt to reestablish the session. However, this will cause
traffic to be interrupted during the connection re-establishement.
If both BGP peer supports TCP-AO, the TLS stack is protected against
payload injection and this attack can be avoided. When enabled, TCP-
AO counters TCP injection attacks listed in [RFC5082].
Furthermore, if the BGP router supports TCP-AO, we recommend an
opportunistic TCP-AO approach as suggested in
[I-D.draft-piraux-tcp-ao-tls]. The router will attempt to connect
using TCP-AO with a default key. When the TLS handshake is finished,
the routers will derive a new TCP-AO key using the TLS key.
5. IANA Considerations
IANA is requested to assign a TCP port (TBD1) from the "Service Name
and Transport Protocol Port Number Registry" as follows:
* Service Name: botls
* Port Number: TBD1
* Transport Protocol: TCP
* Description: BGP over TLS/TCP
* Assignee: IETF
* Contact: IDR WG
* Registration Data: TBD
* Reference: this document
* Unauthorized Use Reported: idr@ietf.org
It is suggested to use the same port as the one selected for BGP over
QUIC [I-D.draft-retana-idr-bgp-quic].
Acknowledgments
The authors thank Dimitri Safonov for the TCP-AO implementation in
Linux.
Change log
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References
Normative References
[I-D.draft-piraux-tcp-ao-tls]
Piraux, M., Bonaventure, O., and T. Wirtgen,
"Opportunistic TCP-AO with TLS", Work in Progress,
Internet-Draft, draft-piraux-tcp-ao-tls-00, 23 October
2023, <https://datatracker.ietf.org/doc/html/draft-piraux-
tcp-ao-tls-00>.
[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>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/rfc/rfc4271>.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis",
RFC 4272, DOI 10.17487/RFC4272, January 2006,
<https://www.rfc-editor.org/rfc/rfc4272>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/rfc/rfc5925>.
[RFC7301] Friedl, S., Popov, A., Langley, A., and E. Stephan,
"Transport Layer Security (TLS) Application-Layer Protocol
Negotiation Extension", RFC 7301, DOI 10.17487/RFC7301,
July 2014, <https://www.rfc-editor.org/rfc/rfc7301>.
[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>.
Informative References
[I-D.draft-retana-idr-bgp-quic]
Retana, A., Qu, Y., Haas, J., Chen, S., and J. Tantsura,
"BGP over QUIC", Work in Progress, Internet-Draft, draft-
retana-idr-bgp-quic-02, 10 July 2023,
<https://datatracker.ietf.org/doc/html/draft-retana-idr-
bgp-quic-02>.
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[RFC5082] Gill, V., Heasley, J., Meyer, D., Savola, P., Ed., and C.
Pignataro, "The Generalized TTL Security Mechanism
(GTSM)", RFC 5082, DOI 10.17487/RFC5082, October 2007,
<https://www.rfc-editor.org/rfc/rfc5082>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
Authors' Addresses
Thomas Wirtgen
UCLouvain & WELRI
Email: thomas.wirtgen@uclouvain.be
Olivier Bonaventure
UCLouvain & WELRI
Email: olivier.bonaventure@uclouvain.be
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