LISP-Security (LISP-SEC)
draft-ietf-lisp-sec-22
| Document | Type | Active Internet-Draft (lisp WG) | |
|---|---|---|---|
| Authors | Fabio Maino , Vina Ermagan , Albert Cabellos-Aparicio , Damien Saucez | ||
| Last updated | 2021-05-18 (latest revision 2021-01-12) | ||
| Replaces | draft-maino-lisp-sec | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | plain text xml pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | WG Consensus: Waiting for Write-Up | |
| Document shepherd | Luigi Iannone | ||
| Shepherd write-up | Show (last changed 2017-03-24) | ||
| IESG | IESG state | I-D Exists (IESG: Dead) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Alvaro Retana | ||
| Send notices to | "Luigi Iannone" <ggx@gigix.net> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
Network Working Group F. Maino
Internet-Draft Cisco Systems
Intended status: Standards Track V. Ermagan
Expires: July 16, 2021 Google
A. Cabellos
Universitat Politecnica de Catalunya
D. Saucez
INRIA
January 12, 2021
LISP-Security (LISP-SEC)
draft-ietf-lisp-sec-22
Abstract
This memo specifies LISP-SEC, a set of security mechanisms that
provides origin authentication, integrity and anti-replay protection
to LISP's EID-to-RLOC mapping data conveyed via mapping lookup
process. LISP-SEC also enables verification of authorization on EID-
prefix claims in Map-Reply messages.
Requirements Language
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 BCP14 [RFC2119]
[RFC8174] when, and only when, they appear in all capitals, as shown
here.
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/.
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 July 16, 2021.
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Copyright Notice
Copyright (c) 2021 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 Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4
3. LISP-SEC Threat Model . . . . . . . . . . . . . . . . . . . . 4
4. Protocol Operations . . . . . . . . . . . . . . . . . . . . . 5
5. LISP-SEC Control Messages Details . . . . . . . . . . . . . . 7
5.1. Encapsulated Control Message LISP-SEC Extensions . . . . 7
5.2. Map-Reply LISP-SEC Extensions . . . . . . . . . . . . . . 10
5.3. Map-Register LISP-SEC Extentions . . . . . . . . . . . . 11
5.4. ITR Processing: Generating a Map-Request . . . . . . . . 12
5.4.1. PITR Processing . . . . . . . . . . . . . . . . . . . 12
5.5. Encrypting and Decrypting an OTK . . . . . . . . . . . . 12
5.5.1. Unencrypted OTK . . . . . . . . . . . . . . . . . . . 14
5.6. Map-Resolver Processing . . . . . . . . . . . . . . . . . 14
5.7. Map-Server Processing . . . . . . . . . . . . . . . . . . 15
5.7.1. Generating a LISP-SEC Protected Encapsulated Map-
Request . . . . . . . . . . . . . . . . . . . . . . . 17
5.7.2. Generating a Proxy Map-Reply . . . . . . . . . . . . 18
5.8. ETR Processing . . . . . . . . . . . . . . . . . . . . . 18
5.9. ITR Processing: Receiving a Map-Reply . . . . . . . . . . 18
5.9.1. Map-Reply Record Validation . . . . . . . . . . . . . 20
6. Security Considerations . . . . . . . . . . . . . . . . . . . 21
6.1. Mapping System Security . . . . . . . . . . . . . . . . . 21
6.2. Random Number Generation . . . . . . . . . . . . . . . . 21
6.3. Map-Server and ETR Colocation . . . . . . . . . . . . . . 21
6.4. Deploying LISP-SEC . . . . . . . . . . . . . . . . . . . 21
6.5. Shared Keys Provisioning . . . . . . . . . . . . . . . . 22
6.6. Replay Attacks . . . . . . . . . . . . . . . . . . . . . 22
6.7. Message Privacy . . . . . . . . . . . . . . . . . . . . . 22
6.8. Denial of Service and Distributed Denial of Service
Attacks . . . . . . . . . . . . . . . . . . . . . . . . . 23
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 23
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7.1. ECM AD Type Registry . . . . . . . . . . . . . . . . . . 23
7.2. Map-Reply AD Type Registry . . . . . . . . . . . . . . . 23
7.3. HMAC Functions . . . . . . . . . . . . . . . . . . . . . 24
7.4. Key Wrap Functions . . . . . . . . . . . . . . . . . . . 24
7.5. Key Derivation Functions . . . . . . . . . . . . . . . . 25
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 25
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.1. Normative References . . . . . . . . . . . . . . . . . . 25
9.2. Informative References . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
The Locator/ID Separation Protocol
[I-D.ietf-lisp-rfc6830bis],[I-D.ietf-lisp-rfc6833bis] is a network-
layer-based protocol that enables separation of IP addresses into two
new numbering spaces: Endpoint Identifiers (EIDs) and Routing
Locators (RLOCs). EID-to-RLOC mappings are stored in a database, the
LISP Mapping System, and made available via the Map-Request/Map-Reply
lookup process. If these EID-to-RLOC mappings, carried through Map-
Reply messages, are transmitted without integrity protection, an
adversary can manipulate them and hijack the communication,
impersonate the requested EID, or mount Denial of Service or
Distributed Denial of Service attacks. Also, if the Map-Reply
message is transported unauthenticated, an adversarial LISP entity
can overclaim an EID-prefix and maliciously redirect traffic directed
to a large number of hosts. The LISP-SEC threat model, described in
Section 3, is built on top of the LISP threat model defined in
[RFC7835], that includes a detailed description of "overclaiming"
attack.
This memo specifies LISP-SEC, a set of security mechanisms that
provides origin authentication, integrity and anti-replay protection
to LISP's EID-to-RLOC mapping data conveyed via mapping lookup
process. LISP-SEC also enables verification of authorization on EID-
prefix claims in Map-Reply messages, ensuring that the sender of a
Map-Reply that provides the location for a given EID-prefix is
entitled to do so according to the EID prefix registered in the
associated Map-Server. Map-Register/Map-Notify security, including
the right for a LISP entity to register an EID-prefix or to claim
presence at an RLOC, is out of the scope of LISP-SEC as those
protocols are protected by the security mechanisms specified in
[I-D.ietf-lisp-rfc6833bis]. However, LISP-SEC extends the Map-
Register message to allow an ITR to securely downgrade to non LISP-
SEC Map-Requests. Additional security considerations are described
in Section 6.
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2. Definition of Terms
One-Time Key (OTK): An ephemeral randomly generated key that must
be used for a single Map-Request/Map-Reply exchange.
ITR One-Time Key (ITR-OTK): The One-Time Key generated at the
Ingress Tunnel Router (ITR).
MS One-Time Key (MS-OTK): The One-Time Key generated at the Map-
Server.
Authentication Data (AD): Metadata that is included either in a
LISP Encapsulated Control Message (ECM) header, as defined in
[I-D.ietf-lisp-rfc6833bis], or in a Map-Reply message to support
confidentiality, integrity protection, and verification of EID-
prefix authorization.
OTK Authentication Data (OTK-AD): The portion of ECM
Authentication Data that contains a One-Time Key.
EID Authentication Data (EID-AD): The portion of ECM and Map-Reply
Authentication Data used for verification of EID-prefix
authorization.
Packet Authentication Data (PKT-AD): The portion of Map-Reply
Authentication Data used to protect the integrity of the Map-Reply
message.
For definitions of other terms, notably Map-Request, Map-Reply,
Ingress Tunnel Router (ITR), Egress Tunnel Router (ETR), Map-Server
(MS), and Map-Resolver (MR) please consult the LISP specification
[I-D.ietf-lisp-rfc6833bis].
3. LISP-SEC Threat Model
LISP-SEC addresses the control plane threats, described in section
3.7 and 3.8 of [RFC7835], that target EID-to-RLOC mappings, including
manipulations of Map-Request and Map-Reply messages, and malicious
ETR EID prefix overclaiming. LISP-SEC makes two main assumptions:
(1) the LISP mapping system is expected to deliver a Map-Request
message to their intended destination ETR as identified by the EID,
and (2) no man-in-the-middle (MITM) attack can be mounted within the
LISP Mapping System. How the Mapping System is protected from MITM
attacks depends from the particular Mapping Systems used, and is out
of the scope of this memo. Furthermore, while LISP-SEC enables
detection of EID prefix overclaiming attacks, it assumes that Map-
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Servers can verify the EID prefix authorization at time of
registration.
According to the threat model described in [RFC7835] LISP-SEC assumes
that any kind of attack, including MITM attacks, can be mounted
outside of the boundaries of the LISP mapping system. An on-path
attacker, outside of the LISP mapping system can, for example, hijack
Map-Request and Map-Reply messages, spoofing the identity of a LISP
node. Another example of on-path attack, called overclaiming attack,
can be mounted by a malicious Egress Tunnel Router (ETR), by
overclaiming the EID-prefixes for which it is authoritative. In this
way the ETR can maliciously redirect traffic directed to a large
number of hosts.
4. Protocol Operations
The goal of the security mechanisms defined in
[I-D.ietf-lisp-rfc6833bis] is to prevent unauthorized insertion of
mapping data by providing origin authentication and integrity
protection for the Map-Register, and by using the nonce to detect
unsolicited Map-Reply sent by off-path attackers.
LISP-SEC builds on top of the security mechanisms defined in
[I-D.ietf-lisp-rfc6833bis] to address the threats described in
Section 3 by leveraging the trust relationships existing among the
LISP entities participating to the exchange of the Map-Request/Map-
Reply messages. Those trust relationships are used to securely
distribute, as described in Section 7.4, a per-message One-Time Key
(OTK) that provides origin authentication, integrity and anti-replay
protection to mapping data conveyed via the mapping lookup process,
and that effectively prevent overclaiming attacks. The processing of
security parameters during the Map-Request/Map-Reply exchange is as
follows:
o Per each Map-Request message a new ITR-OTK is generated and stored
at the ITR, and securely transported to the Map-Server.
o The Map-Server uses the ITR-OTK to compute a Keyed-Hashing for
Message Authentication (HMAC) [RFC2104] that protects the
integrity of the mapping data known to the Map-Server to prevent
overclaiming attacks. The Map-Server also derives a new OTK, the
MS-OTK, that is passed to the ETR, by applying a Key Derivation
Function (KDF) (e.g. [RFC5869]) to the ITR-OTK.
o The ETR uses the MS-OTK to compute an HMAC that protects the
integrity of the Map-Reply sent to the ITR.
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o Finally, the ITR uses the stored ITR-OTK to verify the integrity
of the mapping data provided by both the Map-Server and the ETR,
and to verify that no overclaiming attacks were mounted along the
path between the Map-Server and the ITR.
Section 5 provides the detailed description of the LISP-SEC control
messages and their processing, while the rest of this section
describes the flow of LISP protocol operations at each entity
involved in the Map-Request/Map-Reply exchange:
1. The ITR, upon needing to transmit a Map-Request message,
generates and stores an OTK (ITR-OTK). This ITR-OTK is included
into the Encapsulated Control Message (ECM) that contains the
Map-Request sent to the Map-Resolver. ITR-OTK confidentiality
and integrity protection MUST be provided in the path between the
ITR and the Map-Resolver. This can be achieved either by
encrypting the ITR-OTK with the pre-shared secret known to the
ITR and the Map-Resolver (as specified in Section 5.5), or by
enabling DTLS between the ITR and the Map-Resolver.
2. The Map-Resolver decapsulates the ECM message, decrypts the ITR-
OTK, if needed, and forwards through the Mapping System the
received Map-Request and the ITR-OTK, as part of a new ECM
message. The LISP Mapping System delivers the ECM to the
appropriate Map-Server, as identified by the EID destination
address of the Map-Request. As mentioned in Section 3, how the
Mapping System is protected from MITM attacks depends from the
particular Mapping Systems used, and is out of the scope of this
memo.
3. The Map-Server is configured with the location mappings and
policy information for the ETR responsible for the EID
destination address. Using this preconfigured information, the
Map-Server, after the decapsulation of the ECM message, finds the
longest match EID-prefix that covers the requested EID in the
received Map-Request. The Map-Server adds this EID-prefix,
together with an HMAC computed using the ITR-OTK, to a new
Encapsulated Control Message that contains the received Map-
Request.
4. The Map-Server derives a new OTK, the MS-OTK, by applying a Key
Derivation Function (KDF) to the ITR-OTK. This MS-OTK is
included in the Encapsulated Control Message that the Map-Server
uses to forward the Map-Request to the ETR. MS-OTK
confidentiality and integrity protection MUST be provided in the
path between the Map-Server and the ETR. This can be achieved
either by encrypting the MS-OTK with the pre-shared secret known
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to the Map-Server and the ETR (as specified in Section 5.5), or
by enabling DTLS between the Map-Server and the ETR.
5. If the Map-Server is acting in proxy mode, as specified in
[I-D.ietf-lisp-rfc6833bis], the ETR is not involved in the
generation of the Map-Reply and steps 6 and 7 are skipped. In
this case the Map-Server generates the Map-Reply on behalf of the
ETR as described in Section 5.7.2.
6. The ETR, upon receiving the ECM encapsulated Map-Request from the
Map-Server, decrypts the MS-OTK, if needed, and originates a Map-
Reply that contains the EID-to-RLOC mapping information as
specified in [I-D.ietf-lisp-rfc6833bis].
7. The ETR computes an HMAC over the Map-Reply, keyed with MS-OTK to
protect the integrity of the whole Map-Reply. The ETR also
copies the EID-prefix authorization data that the Map-Server
included in the ECM encapsulated Map-Request into the Map-Reply
message. The ETR then sends the complete Map-Reply message to
the requesting ITR.
8. The ITR, upon receiving the Map-Reply, uses the locally stored
ITR-OTK to verify the integrity of the EID-prefix authorization
data included in the Map-Reply by the Map-Server. The ITR
computes the MS-OTK by applying the same KDF (as specified in the
ECM encapsulated Map-Reply) used by the Map-Server, and verifies
the integrity of the Map-Reply. If the integrity checks fail,
the Map-Reply MUST be discarded. Also, if the EID-prefixes
claimed by the ETR in the Map-Reply are not equal or more
specific than the EID-prefix authorization data inserted by the
Map-Server, the ITR MUST discard the Map-Reply.
5. LISP-SEC Control Messages Details
LISP-SEC metadata associated with a Map-Request is transported within
the Encapsulated Control Message that contains the Map-Request.
LISP-SEC metadata associated with the Map-Reply is transported within
the Map-Reply itself.
5.1. Encapsulated Control Message LISP-SEC Extensions
LISP-SEC uses the ECM defined in [I-D.ietf-lisp-rfc6833bis] with S
bit set to 1 to indicate that the LISP header includes Authentication
Data (AD). The format of the LISP-SEC ECM Authentication Data is
defined in Figure 1 . OTK-AD stands for One-Time Key Authentication
Data and EID-AD stands for EID Authentication Data.
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0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ECM AD Type |V| Unassigned | Requested HMAC ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\
| OTK Length | Key ID | OTK Wrap. ID | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| One-Time-Key Preamble ... | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+OTK-AD
| ... One-Time-Key Preamble | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
~ One-Time Key (128 bits) ~/
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ <---+
| EID-AD Length | KDF ID | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Record Count |E| Unassigned | EID HMAC ID |EID-AD
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\ |
| Unassigned | EID mask-len | EID-AFI | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Rec |
~ EID-prefix ... ~ | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/ |
~ EID HMAC ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ <---+
Figure 1: LISP-SEC ECM Authentication Data
ECM AD Type: 1 (LISP-SEC Authentication Data). See Section 7.
V: Key Version bit. This bit is toggled when the sender switches
to a new OTK wrapping key
Unassigned: Set to 0 on transmission and ignored on receipt.
Requested HMAC ID: The HMAC algorithm, that will be used to
protect the mappings, requested by the ITR. See Section 5.4 for
details, and Section 7.3 for HMAC IDs that MUST be supported.
OTK Length: The length (in bytes) of the OTK Authentication Data
(OTK-AD), that contains the OTK Preamble and the OTK.
Key ID: The identifier of the pre-shared secret shared by an ITR
and the Map-Resolver, and by the Map-Server and an ETR. Per-
message keys are derived from the pre-shared secret to encrypt,
authenticate the origin and protect the integrity of the OTK. The
Key ID allows to rotate between multiple pre-shared secrets in a
non disruptive way.
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OTK Wrapping ID: The identifier of the key derivation function and
of the key wrapping algorithm used to encrypt the One-Time-Key.
See Section 5.5 for more details, and Section 7.4 for Wrapping IDs
that MUST be supported.
One-Time-Key Preamble: set to 0 if the OTK is not encrypted. When
the OTK is encrypted, this field MAY carry additional metadata
resulting from the key wrapping operation. When a 128-bit OTK is
sent unencrypted by Map-Resolver, the OTK Preamble is set to
0x0000000000000000 (64 bits). See Section 5.5.1 for details.
One-Time-Key: the OTK wrapped as specified by OTK Wrapping ID.
See Section 5.5 for details.
EID-AD Length: length (in bytes) of the EID Authentication Data
(EID-AD). The ITR MUST set EID-AD Length to 4 bytes, as it only
fills the KDF ID field, and all the remaining fields part of the
EID-AD are not present. An EID-AD MAY contain multiple EID-
records. Each EID-record is 4-byte long plus the length of the
AFI-encoded EID-prefix.
KDF ID: Identifier of the Key Derivation Function used to derive
the MS-OTK. The ITR MAY use this field to indicate the
recommended KDF algorithm, according to local policy. The Map-
Server can overwrite the KDF ID if it does not support the KDF ID
recommended by the ITR. See Section 5.4 for more details, and
Section 7.5 for KDF IDs that MUST be supported.
Record Count: The number of records in this Map-Request message.
A record is comprised of the portion of the packet that is labeled
'Rec' above and occurs the number of times equal to Record Count.
E: ETR-Cant-Sign bit. This bit is set to 1 to signal to the ITR
that at least one of the ETRs authoritative for the EID prefixes
of this Map-Reply has not enabled LISP-SEC. This allows the ITR
to securely downgrade to non LISP-SEC requests, as specified in
Section 5.7, if so desired.
Unassigned: Set to 0 on transmission and ignored on receipt.
EID HMAC ID: Identifier of the HMAC algorithm used to protect the
integrity of the EID-AD. This field is filled by Map-Server that
computed the EID-prefix HMAC. See Section 5.4 for more details,
and Section 7.3 for HMAC IDs that MUST be supported.
EID mask-len: Mask length for EID-prefix.
EID-AFI: Address family of EID-prefix according to [RFC5226]
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EID-prefix: The Map-Server uses this field to specify the EID-
prefix that the destination ETR is authoritative for, and is the
longest match for the requested EID.
EID HMAC: HMAC of the EID-AD computed and inserted by Map-Server.
Before computing the HMAC operation the EID HMAC field MUST be set
to 0. The HMAC MUST cover the entire EID-AD.
5.2. Map-Reply LISP-SEC Extensions
LISP-SEC uses the Map-Reply defined in [I-D.ietf-lisp-rfc6833bis],
with Type set to 2, and S-bit set to 1 to indicate that the Map-Reply
message includes Authentication Data (AD). The format of the LISP-
SEC Map-Reply Authentication Data is defined in Figure 2. PKT-AD is
the Packet Authentication Data that covers the Map-Reply payload.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MR AD Type | Unassigned |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ <---+
| EID-AD Length | KDF ID | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| Record Count | Unassigned | EID HMAC ID |EID-AD
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+\ |
| Unassigned | EID mask-len | EID-AFI | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Rec |
~ EID-prefix ... ~ | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/ |
~ EID HMAC ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ <---+
| PKT-AD Length | PKT HMAC ID |\
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
~ PKT HMAC ~PKT-AD
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+/
Figure 2: LISP-SEC Map-Reply Authentication Data
MR AD Type: 1 (LISP-SEC Authentication Data). See Section 7.
EID-AD Length: length (in bytes) of the EID-AD. An EID-AD MAY
contain multiple EID-records. Each EID-record is 4-byte long plus
the length of the AFI-encoded EID-prefix.
KDF ID: Identifier of the Key Derivation Function used to derive
MS-OTK. See Section 5.7 for more details, and Section 7.5 for KDF
IDs that MUST be supported.
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Record Count: The number of records in this Map-Reply message. A
record is comprised of the portion of the packet that is labeled
'Rec' above and occurs the number of times equal to Record Count.
Unassigned: Set to 0 on transmission and ignored on receipt.
EID HMAC ID: Identifier of the HMAC algorithm used to protect the
integrity of the EID-AD. See Section 5.7 for more details, and
Section 7.3 for HMAC IDs that MUST be supported.
EID mask-len: Mask length for EID-prefix.
EID-AFI: Address family of EID-prefix according to [RFC8060].
EID-prefix: This field contains an EID-prefix that the destination
ETR is authoritative for, and is the longest match for the
requested EID.
EID HMAC: HMAC of the EID-AD, as computed by the Map-Server.
Before computing the HMAC operation the EID HMAC field MUST be set
to 0. The HMAC covers the entire EID-AD.
PKT-AD Length: length (in bytes) of the Packet Authentication Data
(PKT-AD).
PKT HMAC ID: Identifier of the HMAC algorithm used to protect the
integrity of the Map-Reply. See Section 7.3 for HMAC IDs that
MUST be supported.
PKT HMAC: HMAC of the whole Map-Reply packet, including the LISP-
SEC Authentication Data. The scope of the authentication goes
from the Map-Reply Type field to the PKT HMAC field included.
Before computing the HMAC operation the PKT HMAC field MUST be set
to 0. See Section 5.8 for more details.
5.3. Map-Register LISP-SEC Extentions
This memo is allocating one of the bits marked as Unassigned in the
Map-Register message defined in [I-D.ietf-lisp-rfc6833bis]. More
precisely, the second bit after the Type field in a Map-Register
message is allocated as the S bit. The S bit indicates to the Map-
Server that the registering ETR is LISP-SEC enabled. An ETR that
supports LISP-SEC MUST set the S bit in its Map-Register messages.
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5.4. ITR Processing: Generating a Map-Request
Upon creating a Map-Request, the ITR generates a random ITR-OTK that
is stored locally (until the corresponding Map-Reply is received),
together with the nonce generated as specified in
[I-D.ietf-lisp-rfc6833bis].
ITR-OTK confidentiality and integrity protection MUST be provided in
the path between the ITR and the Map-Resolver. This can be achieved
either by encrypting the ITR-OTK with the pre-shared secret known to
the ITR and the Map-Resolver (see Section 5.5), or by enabling DTLS
between the ITR and the Map-Resolver.
The Map-Request MUST be encapsulated in an ECM, with the S-bit set to
1, to indicate the presence of Authentication Data.
ITR-OTK is wrapped with the algorithm specified by the OTK Wrapping
ID field. See Section 5.5 for further details on OTK encryption. If
the NULL-KEY-WRAP-128 algorithm is selected and DTLS is not enabled
in the path between the ITR and the Map-Resolver, the Map-Request
MUST be dropped and an appropiate log action SHOULD be taken.
The Requested HMAC ID field contains the suggested HMAC algorithm to
be used by the Map-Server and the ETR to protect the integrity of the
ECM Authentication data and of the Map-Reply.
The KDF ID field specifies the suggested key derivation function to
be used by the Map-Server to derive the MS-OTK. A KDF Value of NONE
(0), MAY be used to specify that the ITR has no preferred KDF ID.
The EID-AD length is set to 4 bytes, since the Authentication Data
does not contain EID-prefix Authentication Data, and the EID-AD
contains only the KDF ID field.
5.4.1. PITR Processing
The processing performed by a PITR is equivalent to the processing of
an ITR. However, if the PITR is directly connected to a Mapping
System such as LISP+ALT [RFC6836], the PITR performs the functions of
both the ITR and the Map-Resolver forwarding the Map-Request
encapsulated in an ECM header that includes the Authentication Data
fields as described in Section 5.6.
5.5. Encrypting and Decrypting an OTK
MS-OTK confidentiality and integrity protection MUST be provided in
the path between the Map-Server and the ETR. This can be achieved
either by enabling DTLS between the Map-Server and the ITR or by
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encrypting the MS-OTK with the pre-shared secret known to the Map-
Server and the ETR [I-D.ietf-lisp-rfc6833bis].
Similarly, ITR-OTK confidentiality and integrity protection MUST be
provided in the path between the ITR and the Map-Resolver. This can
be achieved either by enabling DTLS between the Map-Server and the
ITR, or by encrypting the ITR-OTK with the pre-shared secret known to
the ITR and the Map-Resolver. The ITR/Map-Resolver pre-shared key is
similar to the Map-Server/ETR pre-shared key. However, to prevent
ETR's overclaiming attacks, the ITR/Map-Resolver pre-shared secret
MUST have a different value than the Map-Server/ETR pre-shared
secret.
This section describes OTK processing in the ITR/Map-Resolver path,
as well as in the Map-Server/ETR path.
It's important to note that, to prevent ETR's overclaiming attacks,
the ITR/Map-Resolver pre-shared secret MUST be different from the
Map-Server/ETR pre-shared secret.
The OTK is wrapped using the algorithm specified in the OTK Wrapping
ID field. This field identifies both the:
o Key Encryption Algorithm used to encrypt the wrapped OTK, as well
as the
o Key Derivation Function used to derive a per-message encryption
key.
Implementations of this specification MUST support OTK Wrapping ID
AES-KEY-WRAP-128+HKDF-SHA256 that specifies the use of the HKDF-
SHA256 Key Derivation Function specified in[RFC4868] to derive a per-
message encryption key (per-msg-key), as well as the AES-KEY-WRAP-128
Key Wrap algorithm used to encrypt a 128-bit OTK, according to
[RFC3394].
The key wrapping process for OTK Wrapping ID AES-KEY-WRAP-128+HKDF-
SHA256 is described below:
1. The KDF algorithm is identified by the field 'OTK Wrapping ID'
according to the table in Section Section 7.4.
2. The Key Wrap algorithm is identified by the field 'OTK Wrapping
ID' according to the table in Section Section 7.4.
3. If the NULL-KEY-WRAP-128 algorithm (defined in (Section 7.4)) is
selected and DTLS is not enabled, the Map-Request MUST be dropped
and an appropiate log action SHOULD be taken.
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4. The pre-shared secret used to derive the per-msg-key is
represented by PSK[Key ID], that is the pre-shared secret
identified by the 'Key ID'.
5. The per-message encryption key key is computed as:
* per-msg-key = KDF( nonce + s + PSK[Key ID] )
* where the nonce is the value in the Nonce field of the Map-
Request, and
* 's' is the string "OTK-Key-Wrap"
6. According to [RFC3394] the per-msg-key is used to wrap the OTK
with AES-KEY-WRAP-128. The AES Key Wrap Initialization Value
MUST be set to 0xA6A6A6A6A6A6A6A6 (64 bits). The output of the
AES Key Wrap operation is 192-bit long. The most significant
64-bit are copied in the One-Time Key Preamble field, while the
128 less significant bits are copied in the One-Time Key field of
the LISP-SEC Authentication Data.
When decrypting an encrypted OTK the receiver MUST verify that the
Initialization Value resulting from the AES Key Wrap decryption
operation is equal to 0xA6A6A6A6A6A6A6A6. If this verification fails
the receiver MUST discard the entire message.
5.5.1. Unencrypted OTK
MS-OTK confidentiality and integrity protection MUST be provided in
the path between the Map-Server and the ETR. Similarly, ITR-OTK
confidentiality and integrity protection MUST be provided in the path
between the ITR and the Map-Resolver.
However, when DTLS is enabled the OTK MAY be sent unencrypted as
transport layer security is providing confidentiality and integrity
protection.
When a 128-bit OTK is sent unencrypted the OTK Wrapping ID is set to
NULL_KEY_WRAP_128, and the OTK Preamble is set to 0x0000000000000000
(64 bits).
5.6. Map-Resolver Processing
Upon receiving an encapsulated Map-Request with the S-bit set, the
Map-Resolver decapsulates the ECM message. The ITR-OTK, if
encrypted, is decrypted as specified in Section 5.5.
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Protecting the confidentiality of the ITR-OTK and, in general, the
security of how the Map-Request is handed by the Map-Resolver to the
Map-Server, is specific to the particular Mapping System used, and
outside of the scope of this memo.
In Mapping Systems where the Map-Server is compliant with
[I-D.ietf-lisp-rfc6833bis], the Map-Resolver originates a new ECM
header with the S-bit set, that contains the unencrypted ITR-OTK, as
specified in Section 5.5, and the other data derived from the ECM
Authentication Data of the received encapsulated Map-Request.
The Map-Resolver then forwards to the Map-Server the received Map-
Request, encapsulated in the new ECM header that includes the newly
computed Authentication Data fields.
5.7. Map-Server Processing
Upon receiving an ECM encapsulated Map-Request with the S-bit set to
1, the Map-Server process the Map-Request according to the value of
the security-capable S-bit and of the proxy map-reply P-bit contained
in the Map-Register sent by the ETRs authoritative for that prefix
during registration.
Processing of the Map-Request MUST proceed in the order described in
the table below, applying the processing corresponding to the first
rule that matches the conditions indicated in the first column:
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+----------------+--------------------------------------------------+
| Matching | Processing |
| Condition | |
+----------------+--------------------------------------------------+
| 1. At least | The Map-Server MUST generate a LISP-SEC |
| one of the | protected Map-Reply as specified in |
| ETRs | Section 5.7.2. The ETR-Cant-Sign E-bit in the |
| authoritative | EID Authentication Data (EID-AD) MUST be set to |
| for the EID | 0. |
| prefix | |
| included in | |
| the Map- | |
| Request | |
| registered | |
| with the P-bit | |
| set to 1 | |
| | |
| 2. At least | The Map-Server MUST generate a LISP-SEC |
| one of the | protected Encapsulated Map-Request (as specified |
| ETRs | in Section 5.7.1), to be sent to one of the |
| authoritative | authoritative ETRs that registered with the |
| for the EID | S-bit set to 1 (and the P-bit set to 0). If |
| prefix | there is at least one ETR that registered with |
| included in | the S-bit set to 0, the ETR-Cant-Sign E-bit of |
| the Map- | the EID-AD MUST be set to 1 to signal the ITR |
| Request | that a non LISP-SEC Map-Request might reach |
| registered | additional ETRs that have LISP-SEC disabled. |
| with the S-bit | |
| set to 1 | |
| | |
| 3. All the | The Map-Server MUST send a Negative Map-Reply |
| ETRs | protected with LISP-SEC, as described in |
| authoritative | Section 5.7.2. The ETR-Cant-Sign E-bit MUST be |
| for the EID | set to 1 to signal the ITR that a non LISP-SEC |
| prefix | Map-Request might reach additional ETRs that |
| included in | have LISP-SEC disabled. |
| the Map- | |
| Request | |
| registered | |
| with the S-bit | |
| set to 0 | |
+----------------+--------------------------------------------------+
In this way the ITR that sent a LISP-SEC protected Map-Request always
receives a LISP-SEC protected Map-Reply. However, the ETR-Cant-Sign
E-bit set to 1 specifies that a non LISP-SEC Map-Request might reach
additional ETRs that have LISP-SEC disabled. This mechanism allows
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the ITR to securely downgrade to non LISP-SEC requests, if so
desired.
5.7.1. Generating a LISP-SEC Protected Encapsulated Map-Request
The Map-Server decapsulates the ECM and generates a new ECM
Authentication Data. The Authentication Data includes the OTK-AD and
the EID-AD, that contains EID-prefix authorization information, that
are eventually received by the requesting ITR.
The Map-Server updates the OTK-AD by deriving a new OTK (MS-OTK) from
the ITR-OTK received with the Map-Request. MS-OTK is derived
applying the key derivation function specified in the KDF ID field.
If the algorithm specified in the KDF ID field is not supported, the
Map-Server uses a different algorithm to derive the key and updates
the KDF ID field accordingly.
MS-OTK confidentiality and integrity protection MUST be provided in
the path between the Map-Server and the ETR. This can be achieved
either by enabling DTLS between the Map-Server and the ETR, or by
encrypting the MS-OTK with the pre-shared secret known to the Map-
Server and the ETR.
The Map-Request MUST be encapsulated in an ECM, with the S-bit set to
1, to indicate the presence of Authentication Data.
MS-OTK is wrapped with the algorithm specified by the OTK Wrapping ID
field. See Section 5.5 for further details on OTK encryption. If
the NULL-KEY-WRAP-128 algorithm is selected and DTLS is not enabled
in the path between the Map-Server and the ETR, the Map-Request MUST
be dropped and an appropiate log action SHOULD be taken.
The Map-Server includes in the EID-AD the longest match registered
EID-prefix for the destination EID, and an HMAC of this EID-prefix.
The HMAC is keyed with the ITR-OTK contained in the received ECM
Authentication Data, and the HMAC algorithm is chosen according to
the Requested HMAC ID field. If The Map-Server does not support this
algorithm, the Map-Server uses a different algorithm and specifies it
in the EID HMAC ID field. The scope of the HMAC operation covers the
entire EID-AD, from the EID-AD Length field to the EID HMAC field,
which must be set to 0 before the computation.
The Map-Server then forwards the updated ECM encapsulated Map-
Request, that contains the OTK-AD, the EID-AD, and the received Map-
Request to an authoritative ETR as specified in
[I-D.ietf-lisp-rfc6833bis].
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5.7.2. Generating a Proxy Map-Reply
LISP-SEC proxy Map-Reply are generated according to
[I-D.ietf-lisp-rfc6833bis], with the Map-Replay S-bit set to 1. The
Map-Reply includes the Authentication Data that contains the EID-AD,
computed as specified in Section 5.7.1, as well as the PKT-AD
computed as specified in Section 5.8.
5.8. ETR Processing
Upon receiving an ECM encapsulated Map-Request with the S-bit set,
the ETR decapsulates the ECM message. The OTK field, if encrypted,
is decrypted as specified in Section 5.5 to obtain the unencrypted
MS-OTK.
The ETR then generates a Map-Reply as specified in
[I-D.ietf-lisp-rfc6833bis] and includes the Authentication Data that
contains the EID-AD, as received in the encapsulated Map-Request, as
well as the PKT-AD.
The EID-AD is copied from the Authentication Data of the received
encapsulated Map-Request.
The PKT-AD contains the HMAC of the whole Map-Reply packet, keyed
with the MS-OTK and computed using the HMAC algorithm specified in
the Requested HMAC ID field of the received encapsulated Map-Request.
If the ETR does not support the Requested HMAC ID, it uses a
different algorithm and updates the PKT HMAC ID field accordingly.
The scope of the HMAC operation covers the entire PKT-AD, from the
Map-Reply Type field to the PKT HMAC field, which must be set to 0
bendlfore the computation.
Finally the ETR sends the Map-Reply to the requesting ITR as
specified in [I-D.ietf-lisp-rfc6833bis].
5.9. ITR Processing: Receiving a Map-Reply
In response to an encapsulated Map-Request that has the S-bit set, an
ITR MUST receive a Map-Reply with the S-bit set, that includes an
EID-AD and a PKT-AD. If the Map-Reply does not include both ADs, the
ITR MUST discard it. In response to an encapsulated Map-Request with
S-bit set to 0, the ITR expects a Map-Reply with S-bit set to 0, and
the ITR SHOULD discard the Map-Reply if the S-bit is set.
Upon receiving a Map-Reply, the ITR must verify the integrity of both
the EID-AD and the PKT-AD, and MUST discard the Map-Reply if one of
the integrity checks fails. After processing the Map-Reply, the ITR
must discard the <nonce,ITK-OTK> pair associated to the Map-Reply
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The integrity of the EID-AD is verified using the ITR-OTK (stored
locally for the duration of this exchange) to re-compute the HMAC of
the EID-AD using the algorithm specified in the EID HMAC ID field.
If the EID HMAC ID field does not match the Requested HMAC ID the ITR
SHOULD discard the Map-Reply and send, at the first opportunity it
needs to, a new Map-Request with a different Requested HMAC ID field,
according to ITR's local policy. The scope of the HMAC operation
covers the entire EID-AD, from the EID-AD Length field to the EID
HMAC field, which must be set to 0 before the computation of the
HMAC.
ITR MUST set the EID HMAC ID field to 0 before computing the HMAC.
To verify the integrity of the PKT-AD, first the MS-OTK is derived
from the locally stored ITR-OTK using the algorithm specified in the
KDF ID field. This is because the PKT-AD is generated by the ETR
using the MS-OTK. If the KDF ID in the Map-Reply does not match the
KDF ID requested in the Map-Request, the ITR SHOULD discard the Map-
Reply and send, at the first opportunity it needs to, a new Map-
Request with a different KDF ID, according to ITR's local policy.
Without consistent configuration of involved entities, extra delays
may be experienced. However, since HKDF-SHA1-128 is specified as
mandatory to implement in Section 7.5, the process will eventually
converge.
The derived MS-OTK is then used to re-compute the HMAC of the PKT-AD
using the Algorithm specified in the PKT HMAC ID field. If the PKT
HMAC ID field does not match the Requested HMAC ID the ITR SHOULD
discard the Map-Reply and send, at the first opportunity it needs to,
a new Map-Request with a different Requested HMAC ID according to
ITR's local policy or until all HMAC IDs supported by the ITR have
been attempted.
Each individual Map-Reply EID-record is considered valid only if: (1)
both EID-AD and PKT-AD are valid, and (2) the intersection of the
EID-prefix in the Map-Reply EID-record with one of the EID-prefixes
contained in the EID-AD is not empty. After identifying the Map-
Reply record as valid, the ITR sets the EID-prefix in the Map-Reply
record to the value of the intersection set computed before, and adds
the Map-Reply EID-record to its EID-to-RLOC cache, as described in
[I-D.ietf-lisp-rfc6833bis]. An example of Map-Reply record
validation is provided in Section 5.9.1.
The ITR SHOULD send SMR triggered Map-Requests over the mapping
system in order to receive a secure Map-Reply. If an ITR accepts
piggybacked Map-Replies, it SHOULD also send a Map-Request over the
mapping system in order to verify the piggybacked Map-Reply with a
secure Map-Reply.
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5.9.1. Map-Reply Record Validation
The payload of a Map-Reply may contain multiple EID-records. The
whole Map-Reply is signed by the ETR, with the PKT HMAC, to provide
integrity protection and origin authentication to the EID-prefix
records claimed by the ETR. The Authentication Data field of a Map-
Reply may contain multiple EID-records in the EID-AD. The EID-AD is
signed by the Map-Server, with the EID HMAC, to provide integrity
protection and origin authentication to the EID-prefix records
inserted by the Map-Server.
Upon receiving a Map-Reply with the S-bit set, the ITR first checks
the validity of both the EID HMAC and of the PKT-AD HMAC. If either
one of the HMACs is not valid, a log action MUST be taken and the
Map-Reply MUST NOT be processed any further. If both HMACs are
valid, the ITR proceeds with validating each individual EID-record
claimed by the ETR by computing the intersection of each one of the
EID-prefix contained in the payload of the Map-Reply with each one of
the EID-prefixes contained in the EID-AD. An EID-record is valid
only if at least one of the intersections is not the empty set.
For instance, the Map-Reply payload contains 3 mapping record EID-
prefixes:
2001:db8:102::/48
2001:db8:103::/48
2001:db8:200::/40
The EID-AD contains two EID-prefixes:
2001:db8:103::/48
2001:db8:203::/48
The EID-record with EID-prefix 2001:db8:102::/48 is not eligible to
be used by the ITR since it is not included in any of the EID-ADs
signed by the Map-Server. A log action MUST be taken.
The EID-record with EID-prefix 2001:db8:103::/48 is eligible to be
used by the ITR because it matches the second EID-prefix contained in
the EID-AD.
The EID-record with EID-prefix 2001:db8:200::/40 is not eligible to
be used by the ITR since it is not included in any of the EID-ADs
signed by the Map-Server. A log action MUST be taken. In this last
example the ETR is trying to over claim the EID-prefix
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2001:db8:200::/40, but the Map-Server authorized only
2001:db8:203::/48, hence the EID-record is discarded.
6. Security Considerations
6.1. Mapping System Security
The LISP-SEC threat model described in Section 3, assumes that the
LISP Mapping System is working properly and eventually delivers Map-
Request messages to a Map-Server that is authoritative for the
requested EID.
It is assumed that the Mapping System ensures the confidentiality of
the OTK, and the integrity of the Map-Reply data. However, how the
LISP Mapping System is secured is out of the scope of this document.
Similarly, Map-Register security, including the right for a LISP
entity to register an EID-prefix or to claim presence at an RLOC, is
out of the scope of LISP-SEC.
6.2. Random Number Generation
The ITR-OTK MUST be generated by a properly seeded pseudo-random (or
strong random) source. See [RFC4086] for advice on generating
security-sensitive random data
6.3. Map-Server and ETR Colocation
If the Map-Server and the ETR are colocated, LISP-SEC does not
provide protection from overclaiming attacks mounted by the ETR.
However, in this particular case, since the ETR is within the trust
boundaries of the Map-Server, ETR's overclaiming attacks are not
included in the threat model.
6.4. Deploying LISP-SEC
This memo is written according to [RFC2119]. Specifically, the use
of the key word SHOULD "or the adjective 'RECOMMENDED', mean that
there may exist valid reasons in particular circumstances to ignore a
particular item, but the full implications must be understood and
carefully weighed before choosing a different course".
Those deploying LISP-SEC according to this memo, should carefully
weight how the LISP-SEC threat model applies to their particular use
case or deployment. If they decide to ignore a particular
recommendation, they should make sure the risk associated with the
corresponding threats is well understood.
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As an example, in certain closed and controlled deployments, it is
possible that the threat associated with a MiTM between the xTR and
the Mapping System is very low, and after carfeul consideration it
may be decided to allow a NULL key wrapping algorithm while carrying
the OTKs between the xTR and the Mapping System.
As an example at the other end of the spectrum, in certain other
deployments, attackers may be very sophisticated, and force the
deployers to enforce very strict policies in term of HMAC algorithms
accepted by an ITR.
Similar considerations apply to the entire LISP-SEC threat model, and
should guide the deployers and implementors whenever they encounter
the key word SHOULD across this memo.
6.5. Shared Keys Provisioning
Provisioning of the keys shared between the ITR and the Map-Resolver
as well as between the ETR and the Map-Server should be performed via
an orchestration infrastructure and it is out of the scope of this
draft. It is recommended that both shared keys are refreshed at
periodical intervals to address key aging or attackers gaining
unauthorized access to the shared keys. Shared keys should be
unpredictable random values.
6.6. Replay Attacks
An attacker can capture a valid Map-Request and/or Map-Reply and
replay it, however once the ITR receives the original Map-Reply the
<nonce,ITR-OTK> pair stored at the ITR will be discarded. If a
replayed Map-Reply arrives at the ITR, there is no <nonce,ITR-OTK>
that matches the incoming Map-Reply and will be discarded.
In case of replayed Map-Request, the Map-Server, Map-Resolver and ETR
will have to do a LISP-SEC computation. This is equivalent to a
valid LISP-SEC computation and an attacker does not obtain any
benefit.
6.7. Message Privacy
DTLS [RFC6347] SHOULD be used to provide communication privacy and to
prevent eavesdropping, tampering, or message forgery to the messages
exchanged between the ITR, Map-Resolver, Map-Server, and ETR.
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6.8. Denial of Service and Distributed Denial of Service Attacks
LISP-SEC mitigates the risks of Denial of Service and Distributed
Denial of Service attacks by protecting the integrity and
authenticating the origin of the Map-Request/Map-Reply messages, and
by preventing malicious ETRs from overclaiming EID prefixes that
could re-direct traffic directed to a potentially large number of
hosts.
7. IANA Considerations
7.1. ECM AD Type Registry
IANA is requested to create the "ECM Authentication Data Type"
registry with values 0-255, for use in the ECM LISP-SEC Extensions
Section 5.1. The registry MUST be initially populated with the
following values:
Name Value Defined In
-------------------------------------------------
Reserved 0 This memo
LISP-SEC-ECM-EXT 1 This memo
HMAC Functions
Values 2-255 are unassigned. They are to be assigned according to
the "Specification Required" policy defined in [RFC5226].
7.2. Map-Reply AD Type Registry
IANA is requested to create the "Map-Reply Authentication Data Type"
registry with values 0-255, for use in the Map-Reply LISP-SEC
Extensions Section 5.2. The registry MUST be initially populated
with the following values:
Name Value Defined In
-------------------------------------------------
Reserved 0 This memo
LISP-SEC-MR-EXT 1 This memo
HMAC Functions
Values 2-255 are unassigned. They are to be assigned according to
the "Specification Required" policy defined in [RFC5226].
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7.3. HMAC Functions
IANA is requested to create the "LISP-SEC Authentication Data HMAC
ID" registry with values 0-65535 for use as Requested HMAC ID, EID
HMAC ID, and PKT HMAC ID in the LISP-SEC Authentication Data:
Name Number Defined In
-------------------------------------------------
NONE 0 This memo
AUTH-HMAC-SHA-1-96 1 [RFC2104]
AUTH-HMAC-SHA-256-128 2 [RFC6234]
HMAC Functions
Values 3-65535 are unassigned. They are to be assigned according to
the "Specification Required" policy defined in [RFC5226].
AUTH-HMAC-SHA-1-96 MUST be supported, AUTH-HMAC-SHA-256-128 SHOULD be
supported.
7.4. Key Wrap Functions
IANA is requested to create the "LISP-SEC Authentication Data Key
Wrap ID" registry with values 0-65535 for use as OTK key wrap
algorithms ID in the LISP-SEC Authentication Data:
Name Number KEY WRAP KDF
-----------------------------------------------------------------
Reserved 0 None None
NULL-KEY-WRAP-128 1 This memo None
AES-KEY-WRAP-128+HKDF-SHA256 2 [RFC3394] [RFC4868]
Key Wrap Functions
Values 3-65535 are unassigned. They are to be assigned according to
the "Specification Required" policy defined in [RFC5226].
NULL-KEY-WRAP-128, and AES-KEY-WRAP-128+HKDF-SHA256 MUST be
supported.
NULL-KEY-WRAP-128 is used to carry an unencrypted 128-bit OTK, with a
64-bit preamble set to 0x0000000000000000 (64 bits).
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7.5. Key Derivation Functions
IANA is requested to create the "LISP-SEC Authentication Data Key
Derivation Function ID" registry with values 0-65535 for use as KDF
ID in the LISP-SEC Authentication Data:
Name Number Defined In
-------------------------------------------------
NONE 0 This memo
HKDF-SHA1-128 1 [RFC5869]
Key Derivation Functions
Values 2-65535 are unassigned. They are to be assigned according to
the "Specification Required" policy defined in [RFC5226].
HKDF-SHA1-128 MUST be supported
8. Acknowledgements
The authors would like to acknowledge Pere Monclus, Dave Meyer, Dino
Farinacci, Brian Weis, David McGrew, Darrel Lewis and Landon Curt
Noll for their valuable suggestions provided during the preparation
of this document.
9. References
9.1. Normative References
[I-D.ietf-lisp-rfc6833bis]
Farinacci, D., Maino, F., Fuller, V., and A. Cabellos-
Aparicio, "Locator/ID Separation Protocol (LISP) Control-
Plane", draft-ietf-lisp-rfc6833bis-30 (work in progress),
November 2020.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/info/rfc2104>.
[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>.
Maino, et al. Expires July 16, 2021 [Page 25]
Internet-Draft LISP-SEC January 2021
[RFC3394] Schaad, J. and R. Housley, "Advanced Encryption Standard
(AES) Key Wrap Algorithm", RFC 3394, DOI 10.17487/RFC3394,
September 2002, <https://www.rfc-editor.org/info/rfc3394>.
[RFC4086] Eastlake 3rd, D., Schiller, J., and S. Crocker,
"Randomness Requirements for Security", BCP 106, RFC 4086,
DOI 10.17487/RFC4086, June 2005,
<https://www.rfc-editor.org/info/rfc4086>.
[RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-
384, and HMAC-SHA-512 with IPsec", RFC 4868,
DOI 10.17487/RFC4868, May 2007,
<https://www.rfc-editor.org/info/rfc4868>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<https://www.rfc-editor.org/info/rfc5226>.
[RFC5869] Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-Expand
Key Derivation Function (HKDF)", RFC 5869,
DOI 10.17487/RFC5869, May 2010,
<https://www.rfc-editor.org/info/rfc5869>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC6836] Fuller, V., Farinacci, D., Meyer, D., and D. Lewis,
"Locator/ID Separation Protocol Alternative Logical
Topology (LISP+ALT)", RFC 6836, DOI 10.17487/RFC6836,
January 2013, <https://www.rfc-editor.org/info/rfc6836>.
[RFC7835] Saucez, D., Iannone, L., and O. Bonaventure, "Locator/ID
Separation Protocol (LISP) Threat Analysis", RFC 7835,
DOI 10.17487/RFC7835, April 2016,
<https://www.rfc-editor.org/info/rfc7835>.
[RFC8060] Farinacci, D., Meyer, D., and J. Snijders, "LISP Canonical
Address Format (LCAF)", RFC 8060, DOI 10.17487/RFC8060,
February 2017, <https://www.rfc-editor.org/info/rfc8060>.
[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>.
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Internet-Draft LISP-SEC January 2021
9.2. Informative References
[I-D.ietf-lisp-rfc6830bis]
Farinacci, D., Fuller, V., Meyer, D., Lewis, D., and A.
Cabellos-Aparicio, "The Locator/ID Separation Protocol
(LISP)", draft-ietf-lisp-rfc6830bis-36 (work in progress),
November 2020.
Authors' Addresses
Fabio Maino
Cisco Systems
170 Tasman Drive
San Jose, California 95134
USA
Email: fmaino@cisco.com
Vina Ermagan
Google
California
USA
Email: ermagan@gmail.com
Albert Cabellos
Universitat Politecnica de Catalunya
c/ Jordi Girona s/n
Barcelona 08034
Spain
Email: acabello@ac.upc.edu
Damien Saucez
INRIA
2004 route des Lucioles - BP 93
Sophia Antipolis
France
Email: damien.saucez@inria.fr
Maino, et al. Expires July 16, 2021 [Page 27]