secunet Security Networks AG

antony.antony@secunet.com

secunet Security Networks AG

steffen.klassert@secunet.com

sec IPSECME Working Group IKEv2 BEET This document specifies a new Notify Message Type Payload for the Internet Key Exchange Protocol Version 2 (IKEv2), to negotiate IPsec ESP Bound End-to-End Tunnel (BEET) mode. BEET mode combines the benefits of tunnel mode with reduced overhead, making it suitable for applications requiring minimalistic end-to-end tunnels, mobility support, and multi-address multi-homing capabilities. The introduction of the USE_BEET_MODE Notify Message enables the negotiation and establishment of BEET mode security associations.

The Bound End-to-End Tunnel (BEET) mode, as specified in Appendix B of and subsequently updated in , offers an optimized approach for deploying IP Security (IPsec), [RFC4301], using Encapsulating Security Payload (ESP) [RFC4303] for end-to-end use cases. It combines the advantages of Tunnel and Transport modes specified in , while minimizing their overhead for end-to-end use cases. This document specifies the necessary code points to negotiate an ESP BEET mode SA using the Internet Key Exchange Protocol Version 2 (IKEv2) [RFC7296]. This document fills this gap by introducing a new Notify Message Status Type, USE_BEET_MODE, to facilitate the negotiation and establishment of BEET mode security associations in IKEv2.

For over a decade, a minimalist IPsec tunnel mode, BEET, has been in use for end-to-end security in HIP environments without IKE negotiation, . Also, in many environments, with IKE negotiation using a private IKEv2 Notify Message Status Type (strongSWAN). Additionally, BEET mode ESP is valuable for low-power devices which usually use only one end-to-end IPsec tunnel, as it reduces power consumption and complexity. In situations where devices or IPsec connections are dedicated to a single application or transport protocol, the use of BEET mode simplifies packet processing and conserves energy, especially benefiting lower-powered devices.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in .

When negotiating a Child SA using IKEv2, the initiator MUST use the new "USE_BEET_MODE" Notify Message Status Type to request a Child SA pair with BEET mode support. The method used is similar to how USE_TRANSPORT_MODE is negotiated, as described in To request a BEET-mode SA on the Child SA pair, the initiator MUST include the USE_BEET_MODE, Notify Message Status Type, when requesting a new Child SA, either during the IKE_AUTH or the CREATE_CHILD_SA exchanges to create a new Child SA. If the request is accepted, the response MUST also include a USE_BEET_MODE Notification Message Status Type. If the responder declines and does not include the USE_BEET_MODE notification in the response, the child SA may be established without BEET mode enabled. If this is unacceptable to the initiator, the initiator MUST delete the child SA. As the use of the USE_BEET_MODE mode payload is currently only defined for non-transport-mode tunnels, the USE_BEET_MODE notification MUST NOT be combined with the USE_TRANSPORT notification.

• Payload Length - MUST be 0.
• Protocol ID (1 octet) - MUST be 0. MUST be ignored if not 0.
• SPI Size (1 octet) - MUST be 0. MUST be ignored if not 0.

This document defines a new "IKEv2 Notify Message Status Type" to be added to the IANA registry

In this section we discuss the security properties of the BEET mode, discussing some and point out some of its limitations . There are no known new vulnerabilities that the addition of the BEET mode to IKEv2 would create. Since the BEET security associations have the semantics of a fixed, point-to-point tunnel between two IP addresses, it is possible to place one or both of the tunnel end points into other network or nodes but those that actually "possess" the inner IP addresses, i.e., to implement a BEET mode proxy. However, since such usage defeats the security benefits of combined ESP processing, as discussed in , the implementations SHOULD NOT support such usage when used in combination with IKEv2; instead use IKEv2 MOBIKE to move the between networks.

[Note to RFC Editor: Please remove this section and the reference to before publication.] 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 . 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 catalog of available implementations or their features. Readers are advised to note that other implementations may exist. According to , "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". Authors are requested to add a note to the RFC Editor at the top of this section, advising the Editor to remove the entire section before publication, as well as the reference to .

Linux

Organization:

Linux kernel Project

Name:

Linux Kernel

Description:

Implements BEET mode in ESP. The initial support was added in 2006. It is widely used

Level of maturity:

Stable and used for over 15 years

Licensing:

GPLv2

Implementation experience:

There is no support for IPv4 fragments yet. IPv6 fragments appears to work. The BEET mode code is in production for over a decade. And it appears stable.

Contact:

Organization:

The strongSwan Project

Name:

strongSwan

Description:

Implements IKE negotiation and ESP support for BEET mode Linux

Level of maturity:

Stable for a long time

Coverage:

Implements negotiating BEET mode support in Child SA negotiations and using it in ESP. The initial support was added in 2006.

Licensing:

GPLv2

Implementation experience

strongSwan use a private Notify Message Status Type USE_BEET_MODE (40961) for IKE. As far we know BEET is widely used.

Contact

Tobias Brunner tobias@strongswan.org

Organization:

The iproute2 Project

Name:

iproute2

Description:

Implements BEET mode support in ESP. e.g. command support "ip xfrm policy ... mode beet" . and "ip xfrm state .. mode beet". The initial support was added in 2006

Level of maturity:

Stable

Licensing:

GPLv2

Implementation experience:

TBD

Contact:

or Stephen Hemminger stephen@networkplumber.org

We extend our sincere gratitude to the authors and contributors who contributed to the standardization of BEET mode. Their insights and dedication have significantly influenced our work, as well as their contributions to the implementation of BEET mode many years ago.

In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document describes version 2 of the Internet Key Exchange (IKE) protocol. IKE is a component of IPsec used for performing mutual authentication and establishing and maintaining Security Associations (SAs). This document obsoletes RFC 5996, and includes all of the errata for it. It advances IKEv2 to be an Internet Standard. This memo specifies an Encapsulating Security Payload (ESP) based mechanism for transmission of user data packets, to be used with the Host Identity Protocol (HIP). This document obsoletes RFC 5202. All RFCs are required to have a Security Considerations section. Historically, such sections have been relatively weak. This document provides guidelines to RFC authors on how to write a good Security Considerations section. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document describes a simple process that allows authors of Internet-Drafts to record the status of known implementations by including an Implementation Status section. 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. The process in this document is offered as an experiment. Authors of Internet-Drafts are encouraged to consider using the process for their documents, and working groups are invited to think about applying the process to all of their protocol specifications. The authors of this document intend to collate experiences with this experiment and to report them to the community. This document describes a simple process that allows authors of Internet-Drafts to record the status of known implementations by including an Implementation Status section. 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. This process is not mandatory. Authors of Internet-Drafts are encouraged to consider using the process for their documents, and working groups are invited to think about applying the process to all of their protocol specifications. This document obsoletes RFC 6982, advancing it to a Best Current Practice. This document specifies the details of the Host Identity Protocol (HIP). HIP allows consenting hosts to securely establish and maintain shared IP-layer state, allowing separation of the identifier and locator roles of IP addresses, thereby enabling continuity of communications across IP address changes. HIP is based on a Diffie-Hellman key exchange, using public key identifiers from a new Host Identity namespace for mutual peer authentication. The protocol is designed to be resistant to denial-of-service (DoS) and man-in-the-middle (MitM) attacks. When used together with another suitable security protocol, such as the Encapsulating Security Payload (ESP), it provides integrity protection and optional encryption for upper-layer protocols, such as TCP and UDP. This document obsoletes RFC 5201 and addresses the concerns raised by the IESG, particularly that of crypto agility. It also incorporates lessons learned from the implementations of RFC 5201. This document describes the minimal properties that an IP Encapsulating Security Payload (ESP) implementation needs to meet to remain interoperable with the standard ESP as defined in RFC 4303. Such a minimal version of ESP is not intended to become a replacement of ESP in RFC 4303. Instead, a minimal implementation is expected to be optimized for constrained environments while remaining interoperable with implementations of ESP. In addition, this document provides some considerations for implementing minimal ESP in a constrained environment, such as limiting the number of flash writes, handling frequent wakeup and sleep states, limiting wakeup time, and reducing the use of random generation. This document does not update or modify RFC 4303. It provides a compact description of how to implement the minimal version of that protocol. RFC 4303 remains the authoritative description. Ericsson Research Nomadic Lab Ericsson Research Nomadic Lab This document specifies a new mode, called Bound End-to-End Tunnel (BEET) mode, for IPsec ESP. The new mode augments the existing ESP tunnel and transport modes. For end-to-end tunnels, the new mode provides limited tunnel mode semantics without the regular tunnel mode overhead. The mode is intended to support new uses of ESP, including mobility and multi-address multi-homing. HTT Consulting Ericsson Ericsson Software Technology secunet Security Networks AG Linköping University This document is an update to the Bound End-to-End Tunnel (BEET) mode for ESP in as described in [RFC7402]. It brings the description in alignment with the addition of BEET mode for IKEv2 without any processing changes as described in [RFC7402] IANA

This becomes an Appendix.