draft-ietf-6lo-ap-nd-07.txt   draft-ietf-6lo-ap-nd-08.txt 
6lo P. Thubert, Ed. 6lo P. Thubert, Ed.
Internet-Draft Cisco Internet-Draft Cisco
Updates: 6775 (if approved) B. Sarikaya Updates: 6775 (if approved) B. Sarikaya
Intended status: Standards Track Intended status: Standards Track
Expires: March 7, 2019 M. Sethi Expires: April 21, 2019 M. Sethi
Ericsson Ericsson
September 3, 2018 R. Struik
Struik Security Consultancy
October 18, 2018
Address Protected Neighbor Discovery for Low-power and Lossy Networks Address Protected Neighbor Discovery for Low-power and Lossy Networks
draft-ietf-6lo-ap-nd-07 draft-ietf-6lo-ap-nd-08
Abstract Abstract
This document defines an extension to 6LoWPAN Neighbor Discovery (ND) This document specifies an extension to 6LoWPAN Neighbor Discovery
[RFC6775] [I-D.ietf-6lo-rfc6775-update] called Address Protected ND (ND) defined in RFC6775 and updated in [I-D.ietf-6lo-rfc6775-update].
(AP-ND); AP-ND protects the owner of an address against address theft The new extension is called Address Protected Neighbor Discovery (AP-
and impersonation inside a low-power and lossy network (LLN). Nodes ND) and it protects the owner of an address against address theft and
supporting this extension compute a cryptographic Owner Unique impersonation attacks in a low-power and lossy network (LLN). Nodes
Interface ID and associate it with one or more of their Registered supporting this extension compute a cryptographic identifier (Crypto-
Addresses. The Cryptographic ID identifies the owner of the ID) and use it with one or more of their Registered Addresses. The
Registered Address and can be used for proof-of-ownership. It is Crypto-ID identifies the owner of the Registered Address and can be
used in 6LoWPAN ND in place of the EUI-64-based unique ID that is used to provide proof of ownership of the Registered Addresses. Once
associated with the registration. Once an address is registered with an address is registered with the Crypto-ID and a proof-of-ownership
a Cryptographic ID, only the owner of that ID can modify the is provided, only the owner of that address can modify the
registration information of the Registered Address, and Source registration information, thereby enforcing Source Address
Address Validation can be enforced. Validation.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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This Internet-Draft will expire on March 7, 2019. This Internet-Draft will expire on April 21, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. BCP 14 . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. References . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. References . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. 6LoWPAN sub-glossary . . . . . . . . . . . . . . . . . . 4
2.3. 6LoWPAN sub-glossary . . . . . . . . . . . . . . . . . . 5 3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 5
2.4. Crypto-ID . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Updating RFC 6775 . . . . . . . . . . . . . . . . . . . . . . 6
4. New Fields and Options . . . . . . . . . . . . . . . . . . . 6 4. New Fields and Options . . . . . . . . . . . . . . . . . . . 6
4.1. Encoding the Public Key . . . . . . . . . . . . . . . . . 7 4.1. New Crypto-ID . . . . . . . . . . . . . . . . . . . . . . 6
4.2. New Crypto-ID . . . . . . . . . . . . . . . . . . . . . . 7 4.2. Updated EARO . . . . . . . . . . . . . . . . . . . . . . 6
4.3. Updated EARO . . . . . . . . . . . . . . . . . . . . . . 7 4.3. Crypto-ID Parameters Option . . . . . . . . . . . . . . . 8
4.4. Crypto-ID Parameters Option . . . . . . . . . . . . . . . 9 4.4. Nonce Option . . . . . . . . . . . . . . . . . . . . . . 9
4.5. Nonce Option . . . . . . . . . . . . . . . . . . . . . . 10 4.5. NDP Signature Option . . . . . . . . . . . . . . . . . . 9
4.6. NDP Signature Option . . . . . . . . . . . . . . . . . . 10 5. Protocol Scope . . . . . . . . . . . . . . . . . . . . . . . 9
5. Protocol Scope . . . . . . . . . . . . . . . . . . . . . . . 10 6. Protocol Flows . . . . . . . . . . . . . . . . . . . . . . . 10
6. Protocol Flows . . . . . . . . . . . . . . . . . . . . . . . 11 6.1. First Exchange with a 6LR . . . . . . . . . . . . . . . . 11
6.1. First Exchange with a 6LR . . . . . . . . . . . . . . . . 12 6.2. NDPSO generation and verficiation . . . . . . . . . . . . 13
6.2. Multihop Operation . . . . . . . . . . . . . . . . . . . 13 6.3. Multihop Operation . . . . . . . . . . . . . . . . . . . 14
7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
7.1. Inheriting from RFC 3971 . . . . . . . . . . . . . . . . 15 7.1. Inheriting from RFC 3971 . . . . . . . . . . . . . . . . 16
7.2. Related to 6LoWPAN ND . . . . . . . . . . . . . . . . . . 16 7.2. Related to 6LoWPAN ND . . . . . . . . . . . . . . . . . . 17
7.3. ROVR Collisions . . . . . . . . . . . . . . . . . . . . . 16 7.3. ROVR Collisions . . . . . . . . . . . . . . . . . . . . . 17
8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 17 8. IANA considerations . . . . . . . . . . . . . . . . . . . . . 17
8.1. CGA Message Type . . . . . . . . . . . . . . . . . . . . 17 8.1. CGA Message Type . . . . . . . . . . . . . . . . . . . . 17
8.2. Crypto-Type Subregistry . . . . . . . . . . . . . . . . . 17 8.2. Crypto-Type Subregistry . . . . . . . . . . . . . . . . . 17
9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 18
10.1. Normative References . . . . . . . . . . . . . . . . . . 18 10.1. Normative References . . . . . . . . . . . . . . . . . . 18
10.2. Informative references . . . . . . . . . . . . . . . . . 19 10.2. Informative references . . . . . . . . . . . . . . . . . 19
Appendix A. Requirements Addressed in this Document . . . . . . 21 Appendix A. Requirements Addressed in this Document . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
"Neighbor Discovery Optimizations for 6LoWPAN networks" [RFC6775] Neighbor Discovery Optimizations for 6LoWPAN networks [RFC6775]
(6LoWPAN ND) adapts the IPv6 ND (NDv6) protocol [RFC4861][RFC4862] (6LoWPAN ND) adapts the original IPv6 neighbor discovery (NDv6)
(IPv6 ND) for operations over a constrained low-power and lossy protocols defined in [RFC4861] and [RFC4862] for constrained low-
network (LLN). In particular, 6LoWPAN ND introduces a unicast host power and lossy network (LLN). In particular, 6LoWPAN ND introduces
address registration mechanism that reduces the use of multicast a unicast host address registration mechanism that reduces the use of
messages that are present in the NDv6 protocol. 6LoWPAN ND defines a multicast. 6LoWPAN ND defines a new Address Registration Option (ARO)
new Address Registration Option (ARO) that is carried in the unicast that is carried in the unicast Neighbor Solicitation (NS) and
Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages Neighbor Advertisement (NA) messages exchanged between a 6LoWPAN Node
exchanged between a 6LoWPAN Node (6LN) and a 6LoWPAN Router (6LR). (6LN) and a 6LoWPAN Router (6LR). It also defines the Duplicate
It also defines the Duplicate Address Request (DAR) and Duplicate Address Request (DAR) and Duplicate Address Confirmation (DAC)
Address Confirmation (DAC) messages between the 6LR and the 6LoWPAN messages between the 6LR and the 6LoWPAN Border Router (6LBR). In
Border Router (6LBR). In LLN networks, the 6LBR is the central LLN networks, the 6LBR is the central repository of all the
repository of all the registered addresses in its domain. registered addresses in its domain.
The registration mechanism in 6LoWPAN ND [RFC6775] prevents the use The registration mechanism in 6LoWPAN ND [RFC6775] prevents the use
of an address if that address is already registered in the subnet of an address if that address is already registered in the subnet
(first come first serve). In order to validate address ownership, (first come first serve). In order to validate address ownership,
the registration mechanism enables the 6LR and 6LBR to validate the the registration mechanism enables the 6LR and 6LBR to validate the
association between a registered address and a Registration Ownership association between the registered address of a node, and its
Verifier (ROVR). 6LoWPAN ND specifies that the ROVR is derived from Registration Ownership Verifier (ROVR). ROVR is defined in
the MAC address of the device (using the 64-bit Extended Unique [I-D.ietf-6lo-rfc6775-update] and it can be derived from the MAC
Identifier EUI-64 address format specified by IEEE), which can be address of the device (using the 64-bit Extended Unique Identifier
spoofed. Therefore, any node connected to the subnet and aware of a EUI-64 address format specified by IEEE). However, the EUI-64 can be
registered-address-to-ROVR mapping could effectively fake the ROVR, spoofed, and therefore, any node connected to the subnet and aware of
steal the address and redirect traffic for that address towards a a registered-address-to-ROVR mapping could effectively fake the ROVR.
different 6LN. The "Registration Extensions for 6LoWPAN Neighbor This would allow the an attacker to steal the address and redirect
Discovery" [I-D.ietf-6lo-rfc6775-update] defines an Extended ARO traffic for that address. [I-D.ietf-6lo-rfc6775-update] defines an
(EARO) option that allows to transport alternate forms of ROVRs, and Extended Address Registration Option (EARO) option that allows to
is a prerequisite for this specification. transport alternate forms of ROVRs, and is a pre-requisite for this
specification.
According to this specification, a 6LN generates a cryptographic ID In this specification, a 6LN generates a cryptographic ID (Crypto-ID)
(Crypto-ID) and places it in the ROVR field in the registration of and places it in the ROVR field during the registration of one (or
one (or more) of its addresses with the 6LR(s) that the 6LN uses as more) of its addresses with the 6LR(s). Proof of ownership of the
default router(s). Proof of ownership of the cryptographic ID Crypto-ID is passed with the first registration exchange to a new
(Crypto-ID) is passed with the first registration exchange to a new
6LR, and enforced at the 6LR. The 6LR validates ownership of the 6LR, and enforced at the 6LR. The 6LR validates ownership of the
cryptographic ID before it can create a registration, or a change the cryptographic ID before it creates any new registration state, or
information, that is the Link-Layer Address and associated changes existing information.
parameters, in an existing registration state.
The protected address registration protocol proposed in this document The protected address registration protocol proposed in this document
enables Source Address Validation (SAVI) [RFC7039], which ensures enables Source Address Validation (SAVI) [RFC7039]. This ensures
that only the owner uses a registered address in the source address that only the actual owner uses a registered address in the IPv6
field in IPv6 packets. Consequently, a 6LN that sources a packet has source address field. A 6LN can only use a 6LR for forwarding
to use a 6LR to which the source address of the packet is registered packets only if it has previously registered the address used in the
to forward the packet. The 6LR maintains state information for the source field of the IPv6 packet.
registered addressed, including the MAC address, and a link-layer
cryptographic key associated with the 6LN. In SAVI-enforcement mode,
the 6LR allows only packets from a connected Host if the connected
Host owns the registration of the source address of the packet.
The 6lo adaptation layer framework ([RFC4944], [RFC6282]) specifies
that a device forms its IPv6 addresses based on Layer-2 address, so
as to enable a better compression. This is incompatible with "Secure
Neighbor Discovery (SeND)" [RFC3971] and "Cryptographically Generated
Addresses (CGAs)" [RFC3972], which derive the Interface ID (IID) in
the IPv6 addresses from key material. "Privacy Considerations for
IPv6 Address Generation Mechanisms" [RFC7721] places additional
recommendations on the way addresses should be formed and renewed.
This document specifies that a device may form and register addresses The 6lo adaptation layer in [RFC4944] and [RFC6282] requires a device
at will, without a constraint on the way the address is formed or the to form its IPv6 addresses based on its Layer-2 address to enable a
number of addresses that are registered in parallel, Multiple better compression. This is incompatible with Secure Neighbor
addresses with a single ROVR, which only needs to be sent once to a Discovery (SeND) [RFC3971] and Cryptographically Generated Addresses
given 6LR for multiple addresses and registration updates. (CGAs) [RFC3972], since they derive the Interface ID (IID) in IPv6
addresses with cryptographic keys.
2. Terminology 2. Terminology
2.1. BCP 14
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
"OPTIONAL" in this document are to be interpreted as described in BCP document are to be interpreted as described in [RFC2119].
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2.2. References 2.1. References
In this document, readers will encounter terms and concepts that are Terms and concepts from the following documents are used in this
discussed in the following documents: specification:
o "SEcure Neighbor Discovery (SEND)" [RFC3971], o SEcure Neighbor Discovery (SEND) [RFC3971]
o "Cryptographically Generated Addresses (CGA)" [RFC3972], o Cryptographically Generated Addresses (CGA) [RFC3972]
o "Neighbor Discovery for IP version 6" [RFC4861], o Neighbor Discovery for IP version 6 [RFC4861]
o "IPv6 Stateless Address Autoconfiguration" [RFC4862], o IPv6 Stateless Address Autoconfiguration[RFC4862],
o "Problem Statement and Requirements for IPv6 over Low-Power o Problem Statement and Requirements for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Routing" [RFC6606], Wireless Personal Area Network (6LoWPAN) Routing [RFC6606]
o "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): o IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals" [RFC4919], Overview, Assumptions, Problem Statement, and Goals [RFC4919]
o "Neighbor Discovery Optimization for Low-power and Lossy Networks" o Neighbor Discovery Optimization for Low-power and Lossy Networks
[RFC6775], [RFC6775]
o "Terms Used in Routing for Low-Power and Lossy Networks (LLNs)" o Terms Used in Routing for Low-Power and Lossy Networks (LLNs)
[RFC7102], [RFC7102]
o "Terminology for Constrained-Node Networks" [RFC7228], and o Terminology for Constrained-Node Networks [RFC7228]
o "Registration Extensions for 6LoWPAN Neighbor Discovery" o Registration Extensions for 6LoWPAN Neighbor Discovery"
[I-D.ietf-6lo-rfc6775-update] [I-D.ietf-6lo-rfc6775-update]
2.3. 6LoWPAN sub-glossary 2.2. 6LoWPAN sub-glossary
This document often uses the following acronyms: This document uses the following acronyms:
6BBR: 6LoWPAN Backbone Router (proxy for the registration) 6BBR: 6LoWPAN Backbone Router (proxy for the
[I-D.ietf-6lo-backbone-router] registration)[I-D.ietf-6lo-backbone-router]
6LBR: 6LoWPAN Border Router 6LBR: 6LoWPAN Border Router
6LN: 6LoWPAN Node 6LN: 6LoWPAN Node
6LR: 6LoWPAN Router (relay to the registration process) 6LR: 6LoWPAN Router (relay to the registration process)
CIPO: Crypto-ID Parameters Option CIPO: Crypto-ID Parameters Option
(E)ARO: (Extended) Address Registration Option (E)ARO: (Extended) Address Registration Option
skipping to change at page 6, line 4 skipping to change at page 5, line 37
NDPSO: NDP Signature Option NDPSO: NDP Signature Option
NS: Neighbor Solicitation NS: Neighbor Solicitation
ROVR: Registration Ownership Verifier (pronounced rover) ROVR: Registration Ownership Verifier (pronounced rover)
RA: Router Advertisement RA: Router Advertisement
RS: Router Solicitation RS: Router Solicitation
RSAO: RSA Signature Option RSAO: RSA Signature Option
TID: Transaction ID (a sequence counter in the EARO) TID: Transaction ID (a sequence counter in the EARO)
2.4. Crypto-ID
This document defines a new Crypto-ID as an identifier of variable
size which is 64 to 256 bits long. It is generated using
cryptographic means explained later in this document Section 4.2.
"Elliptic Curves for Security" [RFC7748] and "Edwards-Curve Digital
Signature Algorithm (EdDSA)" [RFC8032] provides information on
Elliptic Curve Cryptography (ECC) and a (twisted) Edwards curve,
Ed25519, which can be used with this specification. "Alternative
Elliptic Curve Representations"
[I-D.struik-lwig-curve-representations] provides additional
information on how to represent Montgomery curves and (twisted)
Edwards curves as curves in short-Weierstrass form and illustrates
how this can be used to implement elliptic curve computations using
existing implementations that already implement, e.g., ECDSA and ECDH
using NIST [FIPS-186-4] prime curves.
3. Updating RFC 6775 3. Updating RFC 6775
This specification defines a cryptographic identifier (Crypto-ID) This specification defines a cryptographic identifier (Crypto-ID)
that can be used as a replacement to the MAC address in the ROVR that can be used as a replacement to the MAC address in the ROVR
field of the EARO option; the computation of the Crypto-ID is field of the EARO option; the computation of the Crypto-ID is
detailed in Section 4.2. A node in possession of the necessary detailed in Section 4.1. A node in possession of the necessary
cryptographic material SHOULD use Crypto-ID by default as ROVR in its cryptographic primitives SHOULD use Crypto-ID by default as ROVR in
registration. Whether a ROVR is a Crypto-ID is indicated by a new its registration. Whether a ROVR is a Crypto-ID is indicated by a
"C" flag in the NS(EARO) message. new "C" flag in the NS(EARO) message.
In order to prove its ownership of a Crypto-ID, the registering node In order to prove its ownership of a Crypto-ID, the registering node
needs to supply certain parameters including a nonce and a signature needs to supply certain parameters including a nonce and a signature
that will prove that the node has the private key corresponding to that will prove that the node has the private-key corresponding to
the public key used to build the Crypto-ID. This specification adds the public-key used to build the Crypto-ID. This specification adds
the capability to carry new options in the NS(EARO) and the NA(EARO). the capability to carry new options in the NS(EARO) and the NA(EARO).
The NS(EARO) carries a variation of the CGA Option (Section 4.4), a The NS(EARO) carries a variation of the CGA Option (Section 4.3), a
Nonce option and a variation of the RSA Signature option Nonce option and a variation of the RSA Signature option
(Section 4.6) in the NS(EARO). The NA(EARO) carries a Nonce option. (Section 4.5) in the NS(EARO). The NA(EARO) carries a Nonce option.
4. New Fields and Options 4. New Fields and Options
In order to avoid the need for new ND option types, this In order to avoid the need for new ND option types, this
specification reuses / extends options defined in SEND [RFC3971] and specification reuses/ extends options defined in SEND [RFC3971] and
6LoWPAN ND [RFC6775] [I-D.ietf-6lo-rfc6775-update]. This applies in 6LoWPAN ND [RFC6775] [I-D.ietf-6lo-rfc6775-update]. This applies in
particular to the CGA option and the RSA Signature Option. This particular to the CGA option and the RSA Signature Option. This
specification provides aliases for the specific variations of those specification provides aliases for the specific variations of those
options as used in AP-ND. The presence of the EARO option in the NS/ options as used in this document. The presence of the EARO option in
NA messages indicates that the crypto options are to be processed as the NS/NA messages indicates that the options are to be processed as
specified in this document, not as a SEND message. specified in this document, and not as defined in SEND [RFC3971].
4.1. Encoding the Public Key
A 6LN provides its public key in an NS message. The public key could
be in uncompressed form or in compressed form where the first octet
of the OCTET STRING is 0x04 and 0x02 or 0x03, respectively. Point
compression can further reduce the key size by about 32 octets.
4.2. New Crypto-ID
Each 6LN using a Crypto-ID for registration MUST have a public/
private key pair.
The Crypto-ID is computed as follows: 4.1. New Crypto-ID
1. An 8-bit modifier is selected, enabling a device to form multiple Each 6LN using this specification for address registration MUST
Crypto-IDs with a single key pair. This is useful for privacy support Elliptic Curve Crytpograhy (ECC) and a hash function. The
reasons in order to avoid the correlation of addresses based on choice of elliptic curves and hash function currently defined in this
their Crypto-ID; specification are listed in Section 8.2.
2. the modifier value and the DER-encoded public key (Section 4.1) The Crypto-ID is computed by a 6LN as follows:
are concatenated from left to right;
3. The digital signature is constructed by using the 6LN's private 1. Depending on the Crypto-Type (see Section 8.2) used by the node,
key over its EUI-64 (MAC) address. The signature value is the hash function is applied to the JSON Web Key (JWK) [RFC7517]
computed using the ECDSA signature algorithm and the hash encoding of the public-key of the node.
function used is SHA-256 [RFC6234].
4. the leftmost bits of the resulting hash are used as the Crypto- 2. The leftmost bits of the resulting hash, up to the size of the
ID, up to the size of the ROVR field. ROVR field, are used as the Crypto-ID.
4.3. Updated EARO 4.2. Updated EARO
This specification updates the EARO option as follows: This specification updates the EARO option as follows:
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Status | Opaque | | Type | Length | Status | Opaque |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Rsvd |C| I |R|T| TID | Registration Lifetime | |Rsvd |C| I |R|T| TID | Registration Lifetime |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
skipping to change at page 8, line 35 skipping to change at page 7, line 35
Status: 8-bit unsigned integer. Indicates the status of a Status: 8-bit unsigned integer. Indicates the status of a
registration in the NA response. MUST be set to 0 in registration in the NA response. MUST be set to 0 in
NS messages. NS messages.
Opaque: Defined in [I-D.ietf-6lo-rfc6775-update]. Opaque: Defined in [I-D.ietf-6lo-rfc6775-update].
Rsvd (Reserved): This field is unused. It MUST be initialized to Rsvd (Reserved): This field is unused. It MUST be initialized to
zero by the sender and MUST be ignored by the zero by the sender and MUST be ignored by the
receiver. receiver.
C: This "C" flag is set to indicate that the Owner C: This "C" flag is set to indicate that the ROVR field
Unique ID field contains a Crypto-ID and that the 6LN contains a Crypto-ID and that the 6LN MAY be
MAY be challenged for ownership as specified in this challenged for ownership as specified in this
document. document.
I: Defined in [I-D.ietf-6lo-rfc6775-update]. I: Defined in [I-D.ietf-6lo-rfc6775-update].
R: Defined in [I-D.ietf-6lo-rfc6775-update]. R: Defined in [I-D.ietf-6lo-rfc6775-update].
T and TID: Defined in [I-D.ietf-6lo-rfc6775-update]. T and TID: Defined in [I-D.ietf-6lo-rfc6775-update].
Registration Ownership Verifier (ROVR): When the "C" flag is set, Registration Ownership Verifier (ROVR): When the "C" flag is set,
this field contains a Crypto-ID. this field contains a Crypto-ID.
This specification uses Status values "Validation Requested" and This specification uses Status values "Validation Requested" and
"Validation Failed", which are defined in 6LoWPAN ND "Validation Failed", which are defined in 6LoWPAN ND
[I-D.ietf-6lo-rfc6775-update]. No other new Status values is [I-D.ietf-6lo-rfc6775-update]. No other new Status values are
defined. defined.
4.4. Crypto-ID Parameters Option 4.3. Crypto-ID Parameters Option
This specification defines the Crypto-ID Parameters Option (CIPO), as This specification defines the Crypto-ID Parameters Option (CIPO), as
a variation of the CGA Option that carries the parameters used to a variation of the CGA Option that carries the parameters used to
form a Crypto-ID. In order to provide cryptographic agility form a Crypto-ID. In order to provide cryptographic agility
[RFC7696], AP-ND supports two possible signature algorithms, [RFC7696], AP-ND supports two possible elliptic curves, indicated by
indicated by a Crypto-Type field. Elliptic Curve Cryptography (ECC) a Crypto-Type field. NIST P-256 [FIPS186-4] MUST be supported by all
is used to calculate the Crypto-ID. NIST P-256 [FIPS186-4] MUST be implementations. The Edwards-Curve Digital Signature Algorithm
supported by all implementations. The Edwards-Curve Digital (EdDSA) curve Ed25519ph (pre-hashing) [RFC8032] MAY be supported as
Signature Algorithm (EdDSA) curve Ed25519ph (pre-hashing) [RFC8032] an alternate.
MAY be supported as an alternate.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | Pad Length | Reserved | | Type | Length | Pad Length | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Crypto-Type | Modifier | Reserved | | Crypto-Type | Modifier | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| | | |
. . . .
. Public Key (variable length) . . Public Key (variable length) .
skipping to change at page 10, line 8 skipping to change at page 9, line 5
units of 8 octets. units of 8 octets.
Modifier: 8-bit unsigned integer. Modifier: 8-bit unsigned integer.
Pad Length: 8-bit unsigned integer. The length of the Padding Pad Length: 8-bit unsigned integer. The length of the Padding
field. field.
Crypto-Type: The type of cryptographic algorithm used in Crypto-Type: The type of cryptographic algorithm used in
calculation Crypto-ID. A value of 0 indicates NIST calculation Crypto-ID. A value of 0 indicates NIST
P-256, with SHA-256 as the hash algorithm. A value P-256, with SHA-256 as the hash algorithm. A value
of 1 is assigned for Ed25519ph, with SHA-256 as the of 1 is assigned for Ed25519ph, with SHA-512 as the
hash algorithm. hash algorithm.
Public Key: DER-Encoded Public Key. Public Key: JWK-Encoded Public Key [RFC7517].
Padding: A variable-length field making the option length a Padding: A variable-length field making the option length a
multiple of 8, containing as many octets as specified multiple of 8, containing as many octets as specified
in the Pad Length field. in the Pad Length field.
4.5. Nonce Option 4.4. Nonce Option
This document reuses the Nonce Option defined in section 5.3.2. of This document reuses the Nonce Option defined in section 5.3.2. of
SEND [RFC3971] without a change. SEND [RFC3971] without a change.
4.6. NDP Signature Option 4.5. NDP Signature Option
This document reuses the RSA Signature Option (RSAO) defined in This document reuses the RSA Signature Option (RSAO) defined in
section 5.2. of SEND [RFC3971]. Admittedly, the name is ill-chosen section 5.2. of SEND [RFC3971]. Admittedly, the name is ill-chosen
since the option is extended for non-RSA Signatures and this since the option is extended for non-RSA Signatures and this
specification defines an alias to avoid the confusion. specification defines an alias to avoid the confusion.
The description of the operation on the option detailed in section The description of the operation on the option detailed in section
5.2. of SEND [RFC3971] apply, but for the following changes: 5.2. of SEND [RFC3971] apply, but for the following changes:
o The 128-bit CGA Message Type tag [RFC3972] for AP-ND is 0x8701 o The 128-bit CGA Message Type tag [RFC3972] for AP-ND is 0x8701
55c8 0cca dd32 6ab7 e415 f148 84d0. (The tag value has been 55c8 0cca dd32 6ab7 e415 f148 84d0. (The tag value has been
generated by the editor of this specification on random.org). generated by the editor of this specification on random.org).
o The signature is computed using the hash algorithm and the digital o The signature is computed using the hash algorithm and the digital
signature indicated in the Crypto-Type field of the CIPO option signature indicated in the Crypto-Type field of the CIPO option
using the private key associated with the public key in the CIPO. using the private-key corresponding the public-key passed in the
CIPO.
o The alias NDP Signature Option (NDPSO) can be used to refer to the o The alias NDP Signature Option (NDPSO) can be used to refer to the
RSAO when used as described in this specification. RSAO when used as described in this specification.
5. Protocol Scope 5. Protocol Scope
The scope of the present work is a 6LoWPAN Low Power Lossy Network The scope of the protocol specified here is a 6LoWPAN Low Power Lossy
(LLN), typically a stub network connected to a larger IP network via Network (LLN), typically a stub network connected to a larger IP
a Border Router called a 6LBR per [RFC6775]. A 6LBR has sufficient network via a Border Router called a 6LBR per [RFC6775]. A 6LBR has
capability to satisfy the needs of DAD. sufficient capability to satisfy the needs of duplicate address
detection.
The 6LBR maintains registration state for all devices in its attached The 6LBR maintains registration state for all devices in its attached
LLN. Together with the first-hop router (the 6LR), the 6LBR assures LLN. Together with the first-hop router (the 6LR), the 6LBR assures
uniqueness and grants ownership of an IPv6 address before it can be uniqueness and grants ownership of an IPv6 address before it can be
used in the LLN. This is in contrast to a traditional network that used in the LLN. This is in contrast to a traditional network that
relies on IPv6 address auto-configuration [RFC4862], where there is relies on IPv6 address auto-configuration [RFC4862], where there is
no guarantee of ownership from the network, and each IPv6 Neighbor no guarantee of ownership from the network, and each IPv6 Neighbor
Discovery packet must be individually secured [RFC3971]. Discovery packet must be individually secured [RFC3971].
---+-------- ............ ---+-------- ............
| External Network | External Network
| |
+-----+ +-----+
| | 6LBR | | 6LBR
+-----+ +-----+
o o o o o o
o o o o o o o o
o o LLN o o o o o LLN o o o
o o o (6LR) o o o (6LR)
o (6LN) o (6LN)
Figure 3: Basic Configuration Figure 3: Basic Configuration
In a mesh network, the 6LR is directly connected to the host device. In a mesh network, the 6LR is directly connected to the host device.
This specification mandates that the peer-wise layer-2 security is This specification mandates that the peer-wise layer-2 security is
deployed so that all the packets from a particular host are securely deployed so that all the packets from a particular host are securely
identifiable by the 6LR. The 6LR may be multiple hops away from the identifiable by the 6LR. The 6LR may be multiple hops away from the
6LBR. Packets are routed between the 6LR and the 6LBR via other 6LBR. Packets are routed between the 6LR and the 6LBR via other
6LRs. This specification mandates that a chain of trust is 6LRs. This specification mandates that a chain of trust is
established so that a packet that was validated by the first 6LR can established so that a packet that was validated by the first 6LR can
be safely routed by the next 6LRs to the 6LBR. be safely routed by other on-path 6LRs to the 6LBR.
6. Protocol Flows 6. Protocol Flows
The 6LR/6LBR ensures first-come/first-serve by storing the EARO The 6LR/6LBR ensures first-come/first-serve by storing the EARO
information including the Crypto-ID associated to the node being information including the Crypto-ID associated to the node being
registered. The node can claim any address as long as it is the registered. The node can claim any address as long as it is the
first to make such a claim. After a successful registration, the first to make such a claim. After a successful registration, the
node becomes the owner of the registered address and the address is node becomes the owner of the registered address and the address is
bound to the Crypto-ID in the 6LR/6LBR registry. bound to the Crypto-ID in the 6LR/6LBR registry.
This specification enables the 6LR to verify the ownership of the This specification enables the 6LR to verify the ownership of the
binding at any time assuming that the "C" flag is set. The binding at any time assuming that the "C" flag is set. The
verification prevents other nodes from stealing the address and verification prevents other nodes from stealing the address and
trying to attract traffic for that address or use it as their source trying to attract traffic for that address or use it as their source
address. address.
A node may use multiple IPv6 addresses at the same time. The node A node may use multiple IPv6 addresses at the same time. The node
may use a same Crypto-ID, or multiple crypto-IDs derived from a same may use a same Crypto-ID, to prove the ownership of multiple IPv6
key pair, to protect multiple IPv6 addresses. The separation of the addresses. The separation of the address and the cryptographic
address and the cryptographic material avoids the constrained device material avoids the constrained device to compute multiple keys for
to compute multiple keys for multiple addresses. The registration multiple addresses. The registration process allows the node to use
process allows the node to use the same Crypto-ID for all of its the same Crypto-ID for all of its addresses.
addresses.
6.1. First Exchange with a 6LR 6.1. First Exchange with a 6LR
A 6LN registers to a 6LR that is one hop away from it with the "C" A 6LN registers to a 6LR that is one hop away from it with the "C"
flag set in the EARO, indicating that the ROVR field contains a flag set in the EARO, indicating that the ROVR field contains a
Crypto-ID. The on-link (local) protocol interactions are shown in Crypto-ID. The Target Address in the NS message indicates the IPv6
Figure 4 If the 6LR does not have a state with the 6LN that is address that the 6LN is trying to register. The on-link (local)
consistent with the NS(EARO), then it replies with a challenge NA protocol interactions are shown in Figure 4. If the 6LR does not
(EARO, status=Validation Requested) that contains a Nonce Option. have a state with the 6LN that is consistent with the NS(EARO), then
The Nonce option MUST contain a Nonce value that was never used with it replies with a challenge NA (EARO, status=Validation Requested)
this device. that contains a Nonce Option (shown as NonceLR in Figure 4). The
Nonce option MUST contain a random Nonce value that was never used
with this device.
The 6LN replies to the challenge with an NS(EARO) that includes the The 6LN replies to the challenge with an NS(EARO) that includes a new
echoed Nonce option, the CIPO Section 4.4, and the NDPSO with the Nonce option (shown as NonceLN in Figure 4), the CIPO (Section 4.3),
signature. The information associated to a crypto-ID stored by the and the NDPSO containing the signature. The information associated
6LR on the first NS exchange where it appears. The 6LR SHOULD store to a Crypto-ID stored by the 6LR on the first NS exchange where it
the CIPO parameters associated with the crypto-ID so it can be used appears. The 6LR MUST store the CIPO parameters associated with the
for more than one address. Crypto-ID so it can be used for more than one address.
6LN 6LR 6LN 6LR
| | | |
|<------------------------- RA -------------------------| |<------------------------- RA -------------------------|
| | ^ | | ^
|---------------- NS with EARO (Crypto-ID) ------------>| | |---------------- NS with EARO (Crypto-ID) ------------>| |
| | option | | option
|<- NA with EARO (status=Validation Requested), Nonce --| | |<- NA with EARO (status=Validation Requested), NonceLR-| |
| | v | | v
|-------- NS with EARO, CIPO, Nonce and NDPSO --------->| |------- NS with EARO, CIPO, NonceLN and NDPSO -------->|
| | | |
|<------------------- NA with EARO ---------------------| |<------------------- NA with EARO ---------------------|
| | | |
... ...
| | | |
|--------------- NS with EARO (Crypto-ID) ------------->| |--------------- NS with EARO (Crypto-ID) ------------->|
| | | |
|<------------------- NA with EARO ---------------------| |<------------------- NA with EARO ---------------------|
| | | |
... ...
| | | |
|--------------- NS with EARO (Crypto-ID) ------------->| |--------------- NS with EARO (Crypto-ID) ------------->|
| | | |
|<------------------- NA with EARO ---------------------| |<------------------- NA with EARO ---------------------|
| | | |
Figure 4: On-link Protocol Operation Figure 4: On-link Protocol Operation
The steps for the registration to the 6LR are as follows: The steps for the registration to the 6LR are as follows:
o Upon the first exchange with a 6LR, a 6LN may be challenged to o Upon the first exchange with a 6LR, a 6LN will be challenged to
prove ownership of the Crypto-ID. The proof is not needed again prove ownership of the Crypto-ID and the Target Address being
in later registrations for that address, or when registering other registered in the Neighbor Solicitation message. The proof is not
addresses with the same ROVR. When a 6LR receives a NS(EARO) needed again in later registrations for that address. When a 6LR
registration with a new Crypto-ID as a ROVR, it SHOULD challenge receives a NS(EARO) registration with a new Crypto-ID as a ROVR,
by responding with a NA(EARO) with a status of "Validation it SHOULD challenge by responding with a NA(EARO) with a status of
Requested". This process of validation MAY be skipped in networks "Validation Requested".
where there is no mobility.
o The challenge is triggered when the registration for a Source o The challenge is triggered when the registration for a Source
Link-Layer Address is not verifiable either at the 6LR or the Link-Layer Address is not verifiable either at the 6LR or the
6LBR. In the latter case, the 6LBR returns a status of 6LBR. In the latter case, the 6LBR returns a status of
"Validation Requested" in the DAR/DAC exchange, which is echoed by "Validation Requested" in the DAR/DAC exchange, which is echoed by
the 6LR in the NA (EARO) back to the registering node. The the 6LR in the NA (EARO) back to the registering node. The
challenge MUST NOT alter a valid registration in the 6LR or the challenge MUST NOT alter a valid registration in the 6LR or the
6LBR. 6LBR.
o Upon receiving a NA(EARO) with a status of "Validation Requested", o Upon receiving a NA(EARO) with a status of "Validation Requested",
the registering node SHOULD retry its registration with a Crypto- the registering node SHOULD retry its registration with a Crypto-
ID Parameters Option (CIPO) (Section 4.4) that contains all the ID Parameters Option (CIPO) (Section 4.3) that contains all the
necessary material for building the Crypto-ID, the Nonce and the necessary material for building the Crypto-ID, the NonceLN that it
NDP signature (Section 4.6) options that prove its ownership of generated, and the NDP signature (Section 4.5) option that proves
the Crypto-ID. its ownership of the Crypto-ID and intent of registering the
Target Address.
o In order to validate the ownership, the 6LR performs the same o In order to validate the ownership, the 6LR performs the same
steps as the 6LN and rebuilds the Crypto-ID based on the steps as the 6LN and rebuilds the Crypto-ID based on the
parameters in the CIPO. If the result is different then the parameters in the CIPO. It also verifies the signature contained
validation fails. Else, the 6LR checks the signature in the NDPSO in the NDPSO option. If the Crypto-ID does not match with the
using the public key in the CIPO. If it is correct then the public-key in the CIPO option, or if the signature in the NDPSO
validation passes, else it fails. option cannot be verified, the validation fails.
o If the 6LR fails to validate the signed NS(EARO), it responds with o If the 6LR fails to validate the signed NS(EARO), it responds with
a status of "Validation Failed". After receiving a NA(EARO) with a status of "Validation Failed". After receiving a NA(EARO) with
a status of "Validation Failed", the registering node SHOULD try a status of "Validation Failed", the registering node SHOULD try
an alternate Crypto-ID. The registering node MUST NOT use the to register an alternate target address in the NS message.
same Crypto-ID for subsequent registration attempts.
6.2. Multihop Operation 6.2. NDPSO generation and verficiation
The signature generated by the 6LN to provide proof-of-ownership of
the private-key is carried in the NDP Signature Option (NDPSO). It
is generated by the 6LN as follows:
o Concatenate the following in the order listed:
1. 128-bit type tag (in network byte order)
2. JWK-encoded public key
3. the 16-byte Target Address (in network byte order) sent in the
Neighbor Solicitation (NS) message. It is the address which
the 6LN is registering with the 6LR and 6LBR.
4. NonceLR received from the 6LR (in network byte order) in the
Neighbor Advertisement (NA) message. The random nonce is at
least 6 bytes long as defined in [RFC3971].
5. NonceLN sent from the 6LN (in network byte order). The random
nonce is at least 6 bytes long as defined in [RFC3971].
6. The length of the ROVR field in the NS message cotainting the
Crypto-ID that was sent.
7. 1-byte (in network byte order) Crypto-Type value sent in the
CIPO option.
o Depending on the Crypto-Type (see Section 8.2) chosen by the node
(6LN), apply the hash function on this concatenation.
o Depending on the Crypto-Type (see Section 8.2) chosen by the node
(6LN), sign the hash output with ECDSA (if curve P-256 is used) or
sign the hash with EdDSA (if curve EdDSA25519ph).
The 6LR on receiving the NDPSO and CIPO options first hashes the JWK
encoded public-key in the CIPO option to make sure that the leftmost
bits up to the size of the ROVR match. Only if the check is
successful, it tries to verify the signature in the NDPSO option
using the following.
o Concatenate the following in the order listed:
1. 128-bit type tag (in network byte order)
2. JWK-encoded public key received in the CIPO option
3. the 16-byte Target Address (in network byte order) received in
the Neighbor Solicitation (NS) message. It is the address
which the 6LN is registering with the 6LR and 6LBR.
4. NonceLR sent in the Neighbor Advertisement (NA) message. The
random nonce is at least 6 bytes long as defined in [RFC3971].
5. NonceLN received from the 6LN (in network byte order) in the
NS message. The random nonce is at least 6 bytes long as
defined in [RFC3971].
6. The length of the ROVR field in the NS message containing the
Crypto-ID that was received.
7. 1-byte (in network byte order) Crypto-Type value received in
the CIPO option.
o Depending on the Crypto-Type (see Section 8.2) indicated by the
(6LN) in the CIPO, apply the hash function on this concatenation.
o Verify the signature with the public-key received and the locally
computed values. If the verification succeeds, the 6LR and 6LBR
add the state information about the Crypto-ID, public-key and
Target Address being registered to their database.
6.3. Multihop Operation
In a multihop 6LoWPAN, the registration with Crypto-ID is propagated In a multihop 6LoWPAN, the registration with Crypto-ID is propagated
to 6LBR as described in this section. If the 6LR and the 6LBR to 6LBR as described in this section. If the 6LR and the 6LBR
maintain a security association, then there is no need to propagate maintain a security association, then there is no need to propagate
the proof of ownership to the 6LBR. the proof of ownership to the 6LBR.
A new device that joins the network auto-configures an address and A new device that joins the network auto-configures an address and
performs an initial registration to a neighboring 6LR with an NS performs an initial registration to a neighboring 6LR with an NS
message that carries an Address Registration Option (EARO) [RFC6775]. message that carries an Address Registration Option (EARO) [RFC6775].
The 6LR validates the address with an 6LBR using a DAR/DAC exchange, The 6LR validates the address with an 6LBR using a DAR/DAC exchange,
skipping to change at page 15, line 18 skipping to change at page 16, line 18
Observations regarding the following threats to the local network in Observations regarding the following threats to the local network in
[RFC3971] also apply to this specification. [RFC3971] also apply to this specification.
Neighbor Solicitation/Advertisement Spoofing Neighbor Solicitation/Advertisement Spoofing
Threats in section 9.2.1 of RFC3971 apply. AP-ND counters the Threats in section 9.2.1 of RFC3971 apply. AP-ND counters the
threats on NS(EARO) messages by requiring that the NDP Signature threats on NS(EARO) messages by requiring that the NDP Signature
and CIPO options be present in these solicitations. and CIPO options be present in these solicitations.
Neighbor Unreachability Detection Failure
With RFC6775, a NUD can still be used by the endpoint to assess
the liveness of a device. The NUD request may be protected by
SEND in which case the provision in section 9.2 of RFC 3972
applies. The response to the NUD may be proxied by a backbone
router only if it has a fresh registration state for it. For a
registration being protected by this specification, the proxied
NUD response provides truthful information on the original owner
of the address but it cannot be proven using SEND. If the NUD
response is not proxied, the 6LR will pass the lookup to the end
device which will respond with a traditional NA. If the 6LR does
not have a registration associated for the device, it can issue a
NA with EARO (status=Validation Requested) upon the NA from the
device, which will trigger a NS that will recreate and revalidate
the ND registration.
Duplicate Address Detection DoS Attack Duplicate Address Detection DoS Attack
Inside the LLN, Duplicate Addresses are sorted out using the ROVR, Inside the LLN, Duplicate Addresses are sorted out using the ROVR,
which differentiates it from a movement. DAD coming from the which differentiates it from a movement. DAD coming from the
backbone are not forwarded over the LLN, which provides some backbone are not forwarded over the LLN, which provides some
protection against DoS attacks inside the resource-constrained protection against DoS attacks inside the resource-constrained
part of the network. Over the backbone, the EARO option is part of the network. Over the backbone, the EARO option is
present in NS/NA messages. This protects against misinterpreting present in NS/NA messages. This protects against misinterpreting
a movement for a duplication, and enables the backbone routers to a movement for a duplication, and enables the backbone routers to
determine which one has the freshest registration and is thus the determine which one has the freshest registration and is thus the
skipping to change at page 16, line 4 skipping to change at page 16, line 34
part of the network. Over the backbone, the EARO option is part of the network. Over the backbone, the EARO option is
present in NS/NA messages. This protects against misinterpreting present in NS/NA messages. This protects against misinterpreting
a movement for a duplication, and enables the backbone routers to a movement for a duplication, and enables the backbone routers to
determine which one has the freshest registration and is thus the determine which one has the freshest registration and is thus the
best candidate to validate the registration for the device best candidate to validate the registration for the device
attached to it. But this specification does not guarantee that attached to it. But this specification does not guarantee that
the backbone router claiming an address over the backbone is not the backbone router claiming an address over the backbone is not
an attacker. an attacker.
Router Solicitation and Advertisement Attacks Router Solicitation and Advertisement Attacks
This specification does not change the protection of RS and RA This specification does not change the protection of RS and RA
which can still be protected by SEND. which can still be protected by SEND.
Replay Attacks Replay Attacks
A Nonce given by the 6LR in the NA with EARO (status=Validation Nonces (NonceLR and NonceLN) generated by the 6LR and 6LN
Requested) and echoed in the signed NS guarantees against replay guarantees against replay attacks of the NS(EARO).
attacks of the NS(EARO). The NA(EARO) is not protected and can be
forged by a rogue node that is not the 6LR in order to force the
6LN to rebuild a NS(EARO) with the proof of ownership, but that
rogue node must have access to the L2 radio network next to the
6LN to perform the attack.
Neighbor Discovery DoS Attack Neighbor Discovery DoS Attack
A rogue node that managed to access the L2 network may form many A rogue node that managed to access the L2 network may form many
addresses and register them using AP-ND. The perimeter of the addresses and register them using AP-ND. The perimeter of the
attack is all the 6LRs in range of the attacker. The 6LR must attack is all the 6LRs in range of the attacker. The 6LR must
protect itself against overflows and reject excessive registration protect itself against overflows and reject excessive registration
with a status 2 "Neighbor Cache Full". This effectively blocks with a status 2 "Neighbor Cache Full". This effectively blocks
another (honest) 6LN from registering to the same 6LR, but the 6LN another (honest) 6LN from registering to the same 6LR, but the 6LN
may register to other 6LRs that are in its range but not in that may register to other 6LRs that are in its range but not in that
skipping to change at page 16, line 49 skipping to change at page 17, line 26
compression which derives IPv6 addresses from Layer-2 addresses but compression which derives IPv6 addresses from Layer-2 addresses but
also privacy addresses. also privacy addresses.
7.3. ROVR Collisions 7.3. ROVR Collisions
A collision of Registration Ownership Verifiers (ROVR) (i.e., the A collision of Registration Ownership Verifiers (ROVR) (i.e., the
Crypto-ID in this specification) is possible, but it is a rare event. Crypto-ID in this specification) is possible, but it is a rare event.
The formula for calculating the probability of a collision is 1 - The formula for calculating the probability of a collision is 1 -
e^{-k^2/(2n)} where n is the maximum population size (2^64 here, e^{-k^2/(2n)} where n is the maximum population size (2^64 here,
1.84E19) and K is the actual population (number of nodes). If the 1.84E19) and K is the actual population (number of nodes). If the
Crypto-ID is 64-bits, the chance of a collision is 0.01% when the Crypto-ID is 64-bits (the least possible size allowed), the chance of
network contains 66 million nodes. Moreover, the collision is only a collision is 0.01% when the network contains 66 million nodes.
relevant when this happens within one stub network (6LBR). In the Moreover, the collision is only relevant when this happens within one
case of such a collision, an attacker may be able to claim the stub network (6LBR). In the case of such a collision, an attacker
registered address of an another legitimate node. However for this may be able to claim the registered address of an another legitimate
to happen, the attacker would also need to know the address which was node. However for this to happen, the attacker would also need to
registered by the legitimate node. This registered address is never know the address which was registered by the legitimate node. This
broadcasted on the network and therefore providing an additional registered address is never broadcasted on the network and therefore
64-bits that an attacker must correctly guess. To prevent address providing an additional 64-bits that an attacker must correctly
disclosure, it is RECOMMENDED that nodes derive the address being guess. To prevent address disclosure, it is RECOMMENDED that nodes
registered independently of the ROVR. derive the address being registered independently of the ROVR.
8. IANA considerations 8. IANA considerations
8.1. CGA Message Type 8.1. CGA Message Type
This document defines a new 128-bit value under the CGA Message Type This document defines a new 128-bit value under the CGA Message Type
[RFC3972] namespace, 0x8701 55c8 0cca dd32 6ab7 e415 f148 84d0. [RFC3972] namespace, 0x8701 55c8 0cca dd32 6ab7 e415 f148 84d0.
8.2. Crypto-Type Subregistry 8.2. Crypto-Type Subregistry
skipping to change at page 17, line 35 skipping to change at page 18, line 11
and contains a Signature Algorithm and a Hash Function as shown in and contains a Signature Algorithm and a Hash Function as shown in
Table 1. The following Crypto-Type values are defined in this Table 1. The following Crypto-Type values are defined in this
document: document:
+--------------+-----------------+---------------+------------------+ +--------------+-----------------+---------------+------------------+
| Crypto-Type | Signature | Hash Function | Defining | | Crypto-Type | Signature | Hash Function | Defining |
| value | Algorithm | | Specification | | value | Algorithm | | Specification |
+--------------+-----------------+---------------+------------------+ +--------------+-----------------+---------------+------------------+
| 0 | NIST P-256 | SHA-256 | RFC THIS | | 0 | NIST P-256 | SHA-256 | RFC THIS |
| | [FIPS186-4] | [RFC6234] | | | | [FIPS186-4] | [RFC6234] | |
| 1 | Ed25519ph | SHA-256 | RFC THIS | | 1 | Ed25519ph | SHA-512 | RFC THIS |
| | [RFC8032] | [RFC6234] | | | | [RFC8032] | [RFC6234] | |
+--------------+-----------------+---------------+------------------+ +--------------+-----------------+---------------+------------------+
Table 1: Crypto-Types Table 1: Crypto-Types
As is evident from the table above, although the two curves provide
similar security, they however rely on different hash functions.
Supporting multiple hash functions on constrained devices is not
ideal. [I-D.struik-lwig-curve-representations] provides information
on how to represent Montgomery curves and (twisted) Edwards curves as
curves in short-Weierstrass form and illustrates how this can be used
to implement elliptic curve computations using existing
implementations that already implement, e.g., ECDSA and ECDH using
NIST [FIPS186-4] prime curves. New Crypto-Type values providing
similar or better security (with less code) can be defined in future.
Assignment of new values for new Crypto-Type MUST be done through Assignment of new values for new Crypto-Type MUST be done through
IANA with "Specification Required" and "IESG Approval" as defined in IANA with "Specification Required" and "IESG Approval" as defined in
[RFC8126]. [RFC8126].
9. Acknowledgments 9. Acknowledgments
Many thanks to Charlie Perkins for his in-depth review and Many thanks to Charlie Perkins for his in-depth review and
constructive suggestions. We are also especially grateful to Rene constructive suggestions. We are also especially grateful to Robert
Struik and Robert Moskowitz for their comments that lead to many Moskowitz for his comments that lead to many improvements.
improvements to this document, in particular WRT ECC computation and
references.
10. References 10. References
10.1. Normative References 10.1. Normative References
[FIPS-186-4] [FIPS186-4]
FIPS 186-4, "Digital Signature Standard (DSS), Federal FIPS 186-4, "Digital Signature Standard (DSS), Federal
Information Processing Standards Publication 186-4", US Information Processing Standards Publication 186-4", US
Department of Commerce/National Institute of Standards and Department of Commerce/National Institute of Standards and
Technology Gaithersburg, MD, July 2013. Technology Gaithersburg, MD, July 2013.
[I-D.ietf-6lo-rfc6775-update] [I-D.ietf-6lo-rfc6775-update]
Thubert, P., Nordmark, E., Chakrabarti, S., and C. Thubert, P., Nordmark, E., Chakrabarti, S., and C.
Perkins, "Registration Extensions for 6LoWPAN Neighbor Perkins, "Registration Extensions for 6LoWPAN Neighbor
Discovery", draft-ietf-6lo-rfc6775-update-21 (work in Discovery", draft-ietf-6lo-rfc6775-update-21 (work in
progress), June 2018. progress), June 2018.
skipping to change at page 18, line 45 skipping to change at page 19, line 29
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007, DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>. <https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007, DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>. <https://www.rfc-editor.org/info/rfc4862>.
[RFC6606] Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem
Statement and Requirements for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Routing",
RFC 6606, DOI 10.17487/RFC6606, May 2012,
<https://www.rfc-editor.org/info/rfc6606>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)", Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012, RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>. <https://www.rfc-editor.org/info/rfc6775>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for [RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517,
Constrained-Node Networks", RFC 7228, DOI 10.17487/RFC7517, May 2015,
DOI 10.17487/RFC7228, May 2014, <https://www.rfc-editor.org/info/rfc7517>.
<https://www.rfc-editor.org/info/rfc7228>.
[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>.
10.2. Informative references 10.2. Informative references
[FIPS186-4]
"FIPS Publication 186-4: Digital Signature Standard", July
2013, <http://nvlpubs.nist.gov/nistpubs/FIPS/
NIST.FIPS.186-4.pdf>.
[I-D.ietf-6lo-backbone-router] [I-D.ietf-6lo-backbone-router]
Thubert, P., "IPv6 Backbone Router", draft-ietf-6lo- Thubert, P. and C. Perkins, "IPv6 Backbone Router", draft-
backbone-router-06 (work in progress), February 2018. ietf-6lo-backbone-router-07 (work in progress), September
2018.
[I-D.struik-lwig-curve-representations] [I-D.struik-lwig-curve-representations]
Struik, R., "Alternative Elliptic Curve Representations", Struik, R., "Alternative Elliptic Curve Representations",
draft-struik-lwig-curve-representations-02 (work in draft-struik-lwig-curve-representations-02 (work in
progress), July 2018. progress), July 2018.
[RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6
over Low-Power Wireless Personal Area Networks (6LoWPANs): over Low-Power Wireless Personal Area Networks (6LoWPANs):
Overview, Assumptions, Problem Statement, and Goals", Overview, Assumptions, Problem Statement, and Goals",
RFC 4919, DOI 10.17487/RFC4919, August 2007, RFC 4919, DOI 10.17487/RFC4919, August 2007,
skipping to change at page 20, line 10 skipping to change at page 20, line 26
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234, (SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011, DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/info/rfc6234>. <https://www.rfc-editor.org/info/rfc6234>.
[RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6 [RFC6282] Hui, J., Ed. and P. Thubert, "Compression Format for IPv6
Datagrams over IEEE 802.15.4-Based Networks", RFC 6282, Datagrams over IEEE 802.15.4-Based Networks", RFC 6282,
DOI 10.17487/RFC6282, September 2011, DOI 10.17487/RFC6282, September 2011,
<https://www.rfc-editor.org/info/rfc6282>. <https://www.rfc-editor.org/info/rfc6282>.
[RFC6606] Kim, E., Kaspar, D., Gomez, C., and C. Bormann, "Problem
Statement and Requirements for IPv6 over Low-Power
Wireless Personal Area Network (6LoWPAN) Routing",
RFC 6606, DOI 10.17487/RFC6606, May 2012,
<https://www.rfc-editor.org/info/rfc6606>.
[RFC7039] Wu, J., Bi, J., Bagnulo, M., Baker, F., and C. Vogt, Ed., [RFC7039] Wu, J., Bi, J., Bagnulo, M., Baker, F., and C. Vogt, Ed.,
"Source Address Validation Improvement (SAVI) Framework", "Source Address Validation Improvement (SAVI) Framework",
RFC 7039, DOI 10.17487/RFC7039, October 2013, RFC 7039, DOI 10.17487/RFC7039, October 2013,
<https://www.rfc-editor.org/info/rfc7039>. <https://www.rfc-editor.org/info/rfc7039>.
[RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and
Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January
2014, <https://www.rfc-editor.org/info/rfc7102>. 2014, <https://www.rfc-editor.org/info/rfc7102>.
[RFC7217] Gont, F., "A Method for Generating Semantically Opaque [RFC7217] Gont, F., "A Method for Generating Semantically Opaque
Interface Identifiers with IPv6 Stateless Address Interface Identifiers with IPv6 Stateless Address
Autoconfiguration (SLAAC)", RFC 7217, Autoconfiguration (SLAAC)", RFC 7217,
DOI 10.17487/RFC7217, April 2014, DOI 10.17487/RFC7217, April 2014,
<https://www.rfc-editor.org/info/rfc7217>. <https://www.rfc-editor.org/info/rfc7217>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
[RFC7696] Housley, R., "Guidelines for Cryptographic Algorithm [RFC7696] Housley, R., "Guidelines for Cryptographic Algorithm
Agility and Selecting Mandatory-to-Implement Algorithms", Agility and Selecting Mandatory-to-Implement Algorithms",
BCP 201, RFC 7696, DOI 10.17487/RFC7696, November 2015, BCP 201, RFC 7696, DOI 10.17487/RFC7696, November 2015,
<https://www.rfc-editor.org/info/rfc7696>. <https://www.rfc-editor.org/info/rfc7696>.
[RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
Considerations for IPv6 Address Generation Mechanisms",
RFC 7721, DOI 10.17487/RFC7721, March 2016,
<https://www.rfc-editor.org/info/rfc7721>.
[RFC7748] Langley, A., Hamburg, M., and S. Turner, "Elliptic Curves
for Security", RFC 7748, DOI 10.17487/RFC7748, January
2016, <https://www.rfc-editor.org/info/rfc7748>.
[RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital [RFC8032] Josefsson, S. and I. Liusvaara, "Edwards-Curve Digital
Signature Algorithm (EdDSA)", RFC 8032, Signature Algorithm (EdDSA)", RFC 8032,
DOI 10.17487/RFC8032, January 2017, DOI 10.17487/RFC8032, January 2017,
<https://www.rfc-editor.org/info/rfc8032>. <https://www.rfc-editor.org/info/rfc8032>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
skipping to change at page 22, line 4 skipping to change at page 22, line 20
Pascal Thubert (editor) Pascal Thubert (editor)
Cisco Systems, Inc Cisco Systems, Inc
Building D Building D
45 Allee des Ormes - BP1200 45 Allee des Ormes - BP1200
MOUGINS - Sophia Antipolis 06254 MOUGINS - Sophia Antipolis 06254
FRANCE FRANCE
Phone: +33 497 23 26 34 Phone: +33 497 23 26 34
Email: pthubert@cisco.com Email: pthubert@cisco.com
Behcet Sarikaya Behcet Sarikaya
Plano, TX Plano, TX
USA USA
Email: sarikaya@ieee.org Email: sarikaya@ieee.org
Mohit Sethi Mohit Sethi
Ericsson Ericsson
Hirsalantie
Jorvas 02420 Jorvas 02420
Finland
Email: mohit@piuha.net Email: mohit@piuha.net
Rene Struik
Struik Security Consultancy
Email: rstruik.ext@gmail.com
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