draft-ietf-dhc-sedhcpv6-10.txt   draft-ietf-dhc-sedhcpv6-11.txt 
DHC Working Group S. Jiang DHC Working Group S. Jiang
Internet-Draft Huawei Technologies Co., Ltd Internet-Draft Huawei Technologies Co., Ltd
Intended status: Standards Track L. Li Intended status: Standards Track L. Li
Expires: June 12, 2016 Y. Cui Expires: September 9, 2016 Y. Cui
Tsinghua University Tsinghua University
T. Jinmei T. Jinmei
Infoblox Inc. Infoblox Inc.
T. Lemon T. Lemon
Nominum, Inc. Nominum, Inc.
D. Zhang D. Zhang
December 10, 2015 March 8, 2016
Secure DHCPv6 Secure DHCPv6
draft-ietf-dhc-sedhcpv6-10 draft-ietf-dhc-sedhcpv6-11
Abstract Abstract
The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) enables The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) enables
DHCPv6 servers to pass configuration parameters. It offers DHCPv6 servers to pass configuration parameters. It offers
configuration flexibility. If not being secured, DHCPv6 is configuration flexibility. If not secured, DHCPv6 is vulnerable to
vulnerable to various attacks. This document analyzes the security various attacks. This document analyzes the security issues of
issues of DHCPv6 and specifies a secure DHCPv6 mechanism for the DHCPv6 and specifies the secure DHCPv6 mechanism for authentication
authentication and encryption between DHCPv6 client and DHCPv6 and encryption of messages between a DHCPv6 client and a DHCPv6
server. server.
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.
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on June 12, 2016. This Internet-Draft will expire on September 9, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language and Terminology . . . . . . . . . . . . 3 2. Requirements Language and Terminology . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Issues of DHCPv6 . . . . . . . . . . . . . . . . . . 4 4. Security Issues of DHCPv6 . . . . . . . . . . . . . . . . . . 4
5. secure DHCPv6 overview . . . . . . . . . . . . . . . . . . . 5 5. Secure DHCPv6 Overview . . . . . . . . . . . . . . . . . . . 5
5.1. Solution Overview . . . . . . . . . . . . . . . . . . . . 5 5.1. Solution Overview . . . . . . . . . . . . . . . . . . . . 5
5.2. New Components . . . . . . . . . . . . . . . . . . . . . 7 5.2. New Components . . . . . . . . . . . . . . . . . . . . . 6
5.3. Support for Algorithm Agility . . . . . . . . . . . . . . 7 5.3. Support for Algorithm Agility . . . . . . . . . . . . . . 7
5.4. Imposed Additional Constraints . . . . . . . . . . . . . 8 5.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 7
5.5. Applicability . . . . . . . . . . . . . . . . . . . . . . 8 6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 8
6. DHCPv6 Client Behavior . . . . . . . . . . . . . . . . . . . 9
7. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 11 7. DHCPv6 Server Behavior . . . . . . . . . . . . . . . . . . . 11
8. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . 13 8. Relay Agent Behavior . . . . . . . . . . . . . . . . . . . . 12
9. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 14 9. Processing Rules . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Timestamp Check . . . . . . . . . . . . . . . . . . . . . 14 9.1. Timestamp Check . . . . . . . . . . . . . . . . . . . . . 12
10. Extensions for Secure DHCPv6 . . . . . . . . . . . . . . . . 15 10. Extensions for Secure DHCPv6 . . . . . . . . . . . . . . . . 14
10.1. New DHCPv6 Options . . . . . . . . . . . . . . . . . . . 15 10.1. New DHCPv6 Options . . . . . . . . . . . . . . . . . . . 14
10.1.1. Certificate Option . . . . . . . . . . . . . . . . . 15 10.1.1. Certificate Option . . . . . . . . . . . . . . . . . 14
10.1.2. Signature Option . . . . . . . . . . . . . . . . . . 16 10.1.2. Timestamp Option . . . . . . . . . . . . . . . . . . 15
10.1.3. Timestamp Option . . . . . . . . . . . . . . . . . . 17 10.1.3. Encrypted-message Option . . . . . . . . . . . . . . 16
10.1.4. Encrypted-message Option . . . . . . . . . . . . . . 18 10.2. New DHCPv6 Messages . . . . . . . . . . . . . . . . . . 17
10.2. New DHCPv6 Messages . . . . . . . . . . . . . . . . . . 19 10.3. Status Codes . . . . . . . . . . . . . . . . . . . . . . 17
10.2.1. Encrypted-Query Message . . . . . . . . . . . . . . 19 11. Security Considerations . . . . . . . . . . . . . . . . . . . 18
10.2.2. Encrypted-Response Message . . . . . . . . . . . . . 19 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
10.3. Status Codes . . . . . . . . . . . . . . . . . . . . . . 20 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
11. Security Considerations . . . . . . . . . . . . . . . . . . . 20 14. Change log [RFC Editor: Please remove] . . . . . . . . . . . 20
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 15. Open Issues [RFC Editor: Please remove] . . . . . . . . . . . 21
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22 16. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 16.1. Normative References . . . . . . . . . . . . . . . . . . 22
14.1. Normative References . . . . . . . . . . . . . . . . . . 23 16.2. Informative References . . . . . . . . . . . . . . . . . 23
14.2. Informative References . . . . . . . . . . . . . . . . . 24 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
1. Introduction 1. Introduction
The Dynamic Host Configuration Protocol for IPv6 (DHCPv6, [RFC3315]) The Dynamic Host Configuration Protocol for IPv6 (DHCPv6, [RFC3315])
enables DHCPv6 servers to pass configuration parameters and offers enables DHCPv6 servers to pass configuration parameters and offers
configuration flexibility. If not being secured, DHCPv6 is configuration flexibility. If not being secured, DHCPv6 is
vulnerable to various attacks. vulnerable to various attacks.
This document analyzes the security issues of DHCPv6 in details and This document analyzes the security issues of DHCPv6 and provides the
provides the following mechanisms for improving the security of following mechanisms for improving the security of DHCPv6 between the
DHCPv6 between client and server: DHCPv6 client and the DHCPv6 server:
o the authentication of the DHCPv6 client and the DHCPv6 server to o the authentication of the DHCPv6 client and the DHCPv6 server to
defend against active attack, such as spoofing attack. defend against active attacks, such as spoofing attack.
o the encryption between the DHCPv6 client and the DHCPv6 server in o the encryption between the DHCPv6 client and the DHCPv6 server in
order to protect the DHCPv6 from passive attack, such as pervasive order to protect the DHCPv6 from passive attacks, such as
monitoring. pervasive monitoring.
o the integrity check of DHCPv6 messages by the recipient of the
message based on signature.
o anti-replay protection based on timestamps.
Note: this secure mechanism in this document does not protect outer Note: this secure mechanism in this document does not protect outer
options in Relay-Forward and Relay-Reply messages, either added by a options in Relay-Forward and Relay-Reply messages, either added by a
relay agent toward a server or added by a server toward a relay relay agent toward a server or added by a server toward a relay
agent, because they are only transported within operator networks and agent. Communication between a server and a relay agent, and
considered less vulnerable. Communication between a server and a communications between relay agents, may be secured through the use
relay agent, and communications between relay agents, may be secured of IPsec, as described in section 21.1 in [RFC3315].
through the use of IPsec, as described in section 21.1 in [RFC3315].
The security mechanisms specified in this document achieves the The security mechanism specified in this document achieves DHCPv6
DHCPv6 authentication and encryption based on the sender's public key authentication and encryption based on the sender's certificate. We
certificate. We introduce two new DHCPv6 messages: Encrypted-Query introduce two new DHCPv6 messages: Encrypted-Query message and
message and Encrypted-Response message and four new DHCPv6 options: Encrypted-Response message and three new DHCPv6 options: Certificate
certificate option, signature option, timestamp option and encrypted- option, Timestamp option and Encrypted-message option for DHCPv6
message option for the DHCPv6 authentication and encryption. The authentication and encryption. The Certificate option is used for
certificate option is used for the DHCPv6 authentication. It also DHCPv6 authentication. The Encryption-Query message, Encryption-
integrates signature option for the integrity check and timestamps Response message and Encrypted-message option are used for DHCPv6
option for anti-replay protection. The Encryption-Query message, encryption. The timestamp option is used to defend against replay
Encryption-Response message, and encrypted-message option are used attack.
for the DHCPv6 encryption.
2. Requirements Language and Terminology 2. Requirements Language and Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119] when they document are to be interpreted as described in [RFC2119] when they
appear in ALL CAPS. When these words are not in ALL CAPS (such as appear in ALL CAPS. When these words are not in ALL CAPS (such as
"should" or "Should"), they have their usual English meanings, and "should" or "Should"), they have their usual English meanings, and
are not to be interpreted as [RFC2119] key words. are not to be interpreted as [RFC2119] key words.
skipping to change at page 4, line 29 skipping to change at page 4, line 18
secure DHCPv6 server: A node that responds to requests from clients secure DHCPv6 server: A node that responds to requests from clients
using the authentication and encryption mechanism using the authentication and encryption mechanism
defined in this document. defined in this document.
4. Security Issues of DHCPv6 4. Security Issues of DHCPv6
DHCPv6 is a client/server protocol that provides managed DHCPv6 is a client/server protocol that provides managed
configuration of devices. It enables a DHCPv6 server to configuration of devices. It enables a DHCPv6 server to
automatically configure relevant network parameters on clients. The automatically configure relevant network parameters on clients. The
basic DHCPv6 specification [RFC3315] defines security mechanisms, but basic DHCPv6 specification [RFC3315] defines security mechanisms, but
they have significant flaws and can be improved they have some flaws and can be improved.
The basic DHCPv6 specifications can optionally authenticate the The basic DHCPv6 specifications can optionally authenticate the
origin of message and validate the integrity of messages using an origin of messages and validate the integrity of messages using an
authentication option with a symmetric key pair. [RFC3315] relies on authentication option with a symmetric key pair. [RFC3315] relies on
pre-established secret keys. For any kind of meaningful security, pre-established secret keys. For any kind of meaningful security,
each DHCPv6 client would need to be configured with its own secret each DHCPv6 client would need to be configured with its own secret
key; [RFC3315] provides no mechanism for doing this. key; [RFC3315] provides no mechanism for doing this.
For the out of band approach, operators can set up a key database for For the out of band approach, operators can set up a key database for
both servers and clients from which the client obtains a key before both servers and clients from which the client obtains a key before
running DHCPv6. Manual key distribution runs counter to the goal of running DHCPv6. Manual key distribution runs counter to the goal of
minimizing the configuration data needed at each host. minimizing the configuration data needed at each host.
[RFC3315] provides an additional mechanism for preventing off-network [RFC3315] provides an additional mechanism for preventing off-network
timing attacks using the Reconfigure message: the Reconfigure Key timing attacks using the Reconfigure message: the Reconfigure Key
authentication method. However, this method provides little message authentication method. However, this method protects only the
integrity or source integrity check, and it protects only the Reconfigure message. The key is transmitted in plaintext to the
Reconfigure message. This key is transmitted in plaintext. client in earlier exchanges and so this method is vulnerable to
active attacks.
In addition, the current DHCPv6 messages are still transmitted in In addition, the current DHCPv6 messages are still transmitted in
clear text and the privacy information within the DHCPv6 message is cleartext and the privacy information within the DHCPv6 message is
not protected from passive attack, such as pervasive monitoring. The not protected from passive attack, such as pervasive monitoring. The
IETF has expressed strong agreement that PM is an attack that needs IETF has expressed strong agreement that pervasive monitoring is an
to be mitigated where possible in [RFC7258]. attack that needs to be mitigated where possible in [RFC7258].
In comparison, the security mechanism defined in this document In comparison, the security mechanisms defined in this document
provides the authentication and encryption mechanism based on the provides for authentication and encryption based on the public key
public key certificates on the client or server. The DHCPv6 certificates of the client and server. The DHCPv6 authentication can
authentication can protect DHCPv6 from active attack, such as protect DHCPv6 from active attacks, such as spoofing attack. And the
spoofing attack. And the DHCPv6 encryption defends against passive DHCPv6 encryption defends against passive attacks, such as pervasive
attack, such as pervasive monitoring attack. monitoring attack.
5. secure DHCPv6 overview 5. Secure DHCPv6 Overview
5.1. Solution Overview 5.1. Solution Overview
This solution provides the authentication and encryption mechanisms This solution provides authentication and encryption mechanisms based
based on the public certificates of the DHCPv6 client and server. on the certificates of the DHCPv6 client and server. Before the
Before the standard DHCPv6 configuration process, the Information- standard DHCPv6 configuration process, the Information-request and
request and Reply messages are exchanged to select one authenticated Reply messages are exchanged to select one authenticated DHCPv6
DHCPv6 server. The following DHCPv6 configuration process is server. After the mutual authentication between the DHCPv6 client
encrypted to avoid the privacy disclosure. We introduce two new and server, the following DHCPv6 configuration process is encrypted
to avoid the privacy information disclosure. We introduce two new
DHCPv6 messages: Encrypted-Query message, Encrypted-Response message DHCPv6 messages: Encrypted-Query message, Encrypted-Response message
and four new DHCPv6 options: encrypted-message option, certificate and three new DHCPv6 options: Encrypted-message option, Certificate
option, signature option, timestamp option. Based on the new defined option, Timestamp option. Based on the new defined messages and
messages and options, the corresponding authentication and encryption options, the corresponding authentication and encryption mechanisms
mechanisms are proposed. are achieved.
The following figure illustrates the secure DHCPv6 procedure. The The following figure illustrates secure DHCPv6 procedure. The DHCPv6
DHCPv6 client first sends an Information-request message to the client first sends an Information-request message to the standard
standard multicast address to all DHCPv6 servers. The Information- multicast address to all DHCPv6 servers. The Information-request
request message is used to request the servers for server message is used to request the servers for the servers' certificates
authentication information, without going through any address, prefix information, without going through any address, prefix or non-
or non-security option assignment process. The information-request security option assignment process. The Information-request is sent
is sent without client's privacy information, such as client without any client's private information, such as Client Identifier
identifier option to minimize information leak and increase client's option or the Certificate option, to minimize client's privacy
privacy. When receiving the Information-request message, the server information leakage. When receiving the Information-request message,
sends the Reply message that contains the server's certificate the server sends the Reply message that contains the server's
option, signature option, timestamp option, and server identifier Certificate option and Server Identifier option. Upon the receipt of
option. Upon the receipt of the Reply message, the DHCPv6 client the Reply message, the DHCPv6 client verifies the server's identity
verifies the server's identity according to the contained server according to the contained certificate in the Reply message. If
authentication information in Reply message. If there are multiple there are multiple authenticated DHCPv6 servers, the client selects
authenticated DHCPv6 servers, the client selects one authenticated one authenticated DHCPv6 server for the following DHCPv6
DHCPv6 server for the following DHCPv6 configuration process. If configuration process. If there are no authenticated DHCPv6 servers
there are no authenticated DHCPv6 servers or existing servers failed or existing servers failed authentication, the client should retry a
authentication, the client behavior is policy specific. Depending on number of times. In this way, it is difficult for a rogue server to
its policy, it can choose to connect repeat the server discovery beat out a busy "real" server. And then the client takes some other
process after certain delay or attempt to connect to a different alternative action depending on its local policy.
network.
After the server's authentication, the first DHCPv6 message sent from After the server's authentication, the first DHCPv6 message sent from
client to server, such as Solicit message, contains the client's the client to the server, such as Solicit message, contains the
certificate option, signature option and timestamp option for client client's Certificate information for client authentication. The
authentication. The DHCPv6 message sent from client to server is DHCPv6 client sends the Encrypted-Query message to server, which
encrypted with the server's public key and encapsulated into the carries the Encrypted-message option and the Server Identifier
encrypted-message option. The DHCPv6 client sends the Encrypted- option. The Encrypted-message option contains the encrypted DHCPv6
Query message to server, which carries the server identifier option message sent from the client to the server. When the DHCPv6 server
and the encrypted-message option. When the DHCPv6 server receives receives the Encrypted-Query message, it decrypts the message using
the Encrypted-Query message, it decrypts the message using its its private key. If the decrypted message contains the client's
private key. If the decrypted message contains the client's Certificate option, the DHCPv6 server verifies the client's identity
certificate option, signature option, timestamp option, the DHCPv6 according to the contained client certificate information.
server verifies the client's identity according to the contained
client authentication information. After the client's After the client's authentication, the server sends the Encrypted-
authentication, the server sends the Encrypted-Response message to Response message to the client, which contains the Encrypted-message
the client, which contains the encrypted-message option. The option. The Encrypted-message option contains the encrypted DHCPv6
encrypted-message option contains the encrypted DHCPv6 message sent message sent from server to client, which is encrypted using the
from server to client, which is encrypted using the client's public client's public key. If the message fails client authentication,
key. The message that fails client authentication, MUST be dropped. then the server sends the corresponding error status code to the
And the server sends the corresponding error status code to client. client. During the encrypted DHCPv6 configuration process, the
timestamp option can be contained in the encrypted DHCPv6 messages to
defend against replay attacks.
+-------------+ +-------------+ +-------------+ +-------------+
|DHCPv6 Client| |DHCPv6 Server| |DHCPv6 Client| |DHCPv6 Server|
+-------------+ +-------------+ +-------------+ +-------------+
| Information-request | | Information-request |
|----------------------------------------->| |----------------------------------------->|
| Option Request option | | Option Request option |
| | | |
| Reply | | Reply |
|<-----------------------------------------| |<-----------------------------------------|
| certificate option | | Certificate option |
| signature option | | Server Identifier option |
| timestamp option |
| server identifier option |
| | | |
| Encryption-Query | | Encryption-Query |
|----------------------------------------->| |----------------------------------------->|
| encrypted-message option | | Encrypted-message option |
| server identifier option | | Server Identifier option |
| | | |
| Encryption-Response | | Encryption-Response |
|<-----------------------------------------| |<-----------------------------------------|
| encrypted-message option | | Encrypted-message option |
| | | |
Secure DHCPv6 Procedure Secure DHCPv6 Procedure
It is worth noticing that the signature on a Secure DHCPv6 message
can be expected to significantly increase the size of the message.
One example is normal DHCPv6 message length plus a 1 KB for a X.509
certificate and signature and 256 Byte for a signature. IPv6
fragments [RFC2460] are highly possible. In practise, the total
length would be various in a large range. Hence, deployment of
Secure DHCPv6 should also consider the issues of IP fragment, PMTU,
etc. Also, if there are firewalls between secure DHCPv6 clients and
secure DHCPv6 servers, it is RECOMMENDED that the firewalls are
configured to pass ICMP Packet Too Big messages [RFC4443].
5.2. New Components 5.2. New Components
The new components of the solution specified in this document are as The new components of the mechanism specified in this document are as
follows: follows:
o Servers and clients that use certificates first generate a public/ o Servers and clients that use certificates first generate a public/
private key pair and then obtain a public key certificate from a private key pair and then obtain a certificate that signs the
Certificate Authority that signs the public key. One option is public key. The Certificate option is defined to carry the
defined to carry the certificate. certificate of the sender.
o A signature generated using the private key which is used by the
receiver to verify the integrity of the DHCPv6 messages and then
the authentication of the client/server. Another option is
defined to carry the signature.
o A timestamp that can be used to detect replayed packet. The o A timestamp that can be used to detect replayed packet. The
secure DHCPv6 client/server need to meet some accuracy Timestamp option is defined to carry the current time of the
requirements and be synced to global time, while the timestamp client/server. The secure DHCPv6 client/server need to meet some
checking mechanism allows a configurable time value for clock accuracy requirements and be synced to global time, while the
drift. The real time provision is out of scope of this document. timestamp checking mechanism allows a configurable time value for
Another option is defined to carry the current time of the client/ clock drift. The real time provision is out of scope of this
server. document.
o An encrypted-message option that contains the encrypted DHCPv6 o The Encrypted-message option that contains the encrypted DHCPv6
message. message.
o An Encrypted-Query message that sent from client to server. The o The Encrypted-Query message that is sent from the secure DHCPv6
Encrypted-Query message contains the encrypted-message option and client to the secure DHCPv6 server. The Encrypted-Query message
server identifier option. contains the Encrypted-message option and Server Identifier
o An Encrypted-Response message that sent from server to client.
The Encrypted-Response message contains the encrypted-message
option. option.
5.3. Support for Algorithm Agility o The Encrypted-Response message that is sent from the secure DHCPv6
server to the secure DHCPv6 client. The Encrypted-Response
Hash functions are used to provide message integrity checks. In message contains the Encrypted-message option.
order to provide a means of addressing problems that may emerge in
the future with existing hash algorithms, as recommended in
[RFC4270], this document provides a mechanism for negotiating the use 5.3. Support for Algorithm Agility
of more secure hashes in the future.
In addition to hash algorithm agility, this document also provides a Encryption algorithm is used for DHCPv6 encryption to defend against
mechanism for signature algorithm agility. passive attack. In order to provide a means of addressing problems
that may emerge in the future with existing encryption algorithms,
this document provides a mechanism for negotiating the use of more
encryption algorithms in the future.
The support for algorithm agility in this document is mainly a The support for algorithm agility in this document is mainly a
unilateral notification mechanism from sender to recipient. A unilateral notification mechanism from sender to recipient. A
recipient MAY support various algorithms simultaneously among recipient MAY support various algorithms simultaneously among
different senders, and the different senders in the same different senders, and the different senders in a same administrative
administrative domain may be allowed to use various algorithms domain may be allowed to use various algorithms simultaneously. It
simultaneously. It is NOT RECOMMENDED that the same sender and is NOT RECOMMENDED that the same sender and recipient use various
recipient use various algorithms in a single communication session. algorithms in a single communication session.
If the recipient does not support the algorithm used by the sender, If the server does not support the algorithm used by the client, the
it cannot authenticate the message. In the client-to-server case, server SHOULD reply with an AlgorithmNotSupported status code
the server SHOULD reply with an AlgorithmNotSupported status code (defined in Section 10.3) to the client. Upon receiving this status
(defined in Section 10.3). Upon receiving this status code, the code, the client MAY resend the message protected with the mandatory
client MAY resend the message protected with the mandatory algorithm algorithm (defined in Section 10.1.1).
(defined in Section 10.1.2).
5.4. Imposed Additional Constraints 5.4. Applicability
The client/server that supports the identity verification MAY impose In principle, Secure DHCPv6 is applicable in any environment where
additional constraints for the verification. For example, it may physical security on the link is not assured and attacks on DHCPv6
impose limits on minimum and maximum key lengths. are a concern. In practice, however, it will rely on some
operational assumptions mainly regarding public key distribution and
management, until more lessons are learned and more experiences are
achieved.
Minbits The minimum acceptable key length for public keys. An upper One feasible environment in an early deployment stage would be
limit MAY also be set for the amount of computation needed when enterprise networks. In such networks the security policy tends to
verifying packets that use these security associations. The be strict and it will be easier to manage client hosts. One trivial
appropriate lengths SHOULD be set according to the signature deployment scenario is therefore to manually pre-configure client
algorithm and also following prudent cryptographic practice. For with the trusted servers' public key and manually register clients'
example, minimum length 1024 and upper limit 2048 may be used for public keys for the server. It may also be possible to deploy an
RSA [RSA]. internal PKI to make this less reliant on manual operations, although
it is currently subject to future study specifically how to integrate
such a PKI into the DHCPv6 service for the network.
5.5. Applicability Note that this deployment scenario based on manual operation is not
different very much from the existing, shared-secret based
authentication mechanisms defined in [RFC3315] in terms of
operational costs. However, Secure DHCPv6 is still securer than the
shared-secret mechanism in that even if clients' keys stored for the
server are stolen that does not mean an immediate threat as these are
public keys. In addition, if some kind of PKI is used with Secure
DHCPv6, even if the initial installation of the certificates is done
manually, it will help reduce operational costs of revocation in case
a private key (especially that of the server) is compromised.
Secure DHCPv6 is applicable in environments where physical security It is believed that Secure DHCPv6 could be more widely applicable
on the link is not assured and attacks on DHCPv6 are a concern, such with integration of generic PKI so that it will be more easily
as enterprise network. In enterprise network, the security policy is deployed. But such a deployment requires more general issues with
strict and the clients are stable terminals. The PKI model is used PKI deployment be addressed, and it is currently unknown whether we
for the secure DHCPv6 deployment. The deployment of PKI is out of can find practical deployment scenarios. It is subject to future
the scope of this document. The server is always considered to have study and experiments, and out of scope of this document.
connectivity to authorized CA and verify the clients' certificates.
The client performs the server authentication locally. The trusted
servers' certificates or trusted CAs' certificates, which form a
certification path [RFC5280], is deployed in the client to achieve
the server authentication. The DHCPv6 client obtains the trusted
certificates through the pre-configuration method or out of band,
such as QR code. After the mutual authentication, the DHCPv6 message
is encrypted with the recipient's public key, which is contained in
the certificate.
6. DHCPv6 Client Behavior 6. DHCPv6 Client Behavior
For the security DHCPv6 client, it must have a public certificate. For the secure DHCPv6 client, a certificate is needed for client
The client may be pre-configured with a public key certificate, which authentication. The client is pre-configured with a certificate and
is signed by a CA trusted by the server, and its corresponding its corresponding private key. If the client is pre-configured with
private key. public key not certificate, it can generate the self-signed
certificate for client authentication.
The DHCPv6 client multicasts the Information-request message to the The secure DHCPv6 client multicasts the Information-request message
DHCPv6 servers. The Information-request message MUST NOT include any to the DHCPv6 servers. The Information-request message MUST NOT
option which may reveal the private information of the client, such include any option which may reveal the private information of the
as the client identifier option. The information-request message is client, such as the Client Identifier option or the Certificate
used by the DHCPv6 client to request the server's identity option. The Information-request message is used by the DHCPv6 client
verification information without having addresses, prefixes or any to request the server's identity verification information without
non-security options assigned to it. The Option Request option in having addresses, prefixes or any non-security options assigned to
the Information-request message MUST contain the option code of it. The Option Request option in the Information-request message
certificate option, signature option, timestamp option, and server MUST contain the option code of the Certificate option.
identifier option.
When receiving the Reply messages from DHCPv6 servers, a secure When receiving the Reply messages from DHCPv6 servers, a secure
DHCPv6 client SHOULD discard any DHCPv6 messages that meet any of the DHCPv6 client SHOULD discard any DHCPv6 messages when the Certificate
following conditions: option or Server Identifier option is missing. And then the client
SHOULD first check the support of the encryption algorithm that the
o the signature option is missing, server used. If the check fails, the Reply message SHOULD be
dropped. If the encryption algorithm is supported, the client then
o multiple signature options are present, checks the authority of this server. The client SHOULD also use the
same algorithms in the return messages.
o the certificate option is missing.
And then the client SHOULD first check the support of the hash and
signature algorithms that the server used. If the check fails, the
Reply message SHOULD be dropped. If both hash and signature
algorithms are supported, the client then checks the authority of
this server. The client SHOULD also use the same algorithms in the
return messages.
The client SHOULD validate the certificate according to the rules The client SHOULD validate the certificate according to the rules
defined in [RFC5280]. An implementation may create a local trust defined in [RFC5280]. An implementation may create a local trust
certificate record for verified certificates in order to avoid certificate record for verified certificates in order to avoid
repeated verification procedure in the future. A certificate that repeated verification procedure in the future. A certificate that
finds a match in the local trust certificate list is treated as finds a match in the local trust certificate list is treated as
verified. At this point, the client has either recognized the verified. The message transaction-id is used as the identifier of
authentication of the server, or decided to drop the message. the authenticated server's public key for encryption. At this point,
the client has either recognized the certificate of the server, or
The client MUST now authenticate the server by verifying the decided to drop the message.
signature and checking timestamp (see details in Section 9.1), if
there is a timestamp option. The order of two procedures is left as
an implementation decision. It is RECOMMENDED to check timestamp
first, because signature verification is much more computationally
expensive.
The signature field verification MUST show that the signature has
been calculated as specified in Section 10.1.2. Only the messages
that get through both the signature verification and timestamp check
(if there is a timestamp option) are accepted. Reply message that
does not pass the above tests MUST be discarded.
If there are multiple authenticated DHCPv6 servers, the client If there are multiple authenticated DHCPv6 servers, the client
selects one DHCPv6 server for the following network parameters selects one DHCPv6 server for the following network parameters
configuration. If there are no authenticated DHCPv6 servers or configuration. The client can also choose other implementation
existing servers failed authentication, the client behavior is policy method depending on the client's local policy if the defined protocol
specific. Depending on its policy, it can choose to connect using can also run normally. For example, the client can try multiple
plain, unencrypted DHCPv6, repeat the server discovery process after transactions (each with different server) at the "same" time. If
certain delay or attempt to connect to a different network. The there are no authenticated DHCPv6 servers or existing servers failed
client MUST NOT conduct the server discovery process immediately to authentication, the client should retry a number of times. In this
avoid the packet storm. way, it is difficult for the rogue server to beat out a busy "real"
server. And then the client takes some alternative action depending
on its local policy, such as attempting to use an unsecured DHCPv6
server. The client conducts the server discovery process as per
section 18.1.5 of [RFC3315] to avoid the packet storm.
Once the server has been authenticated, the DHCPv6 client sends the Once the server has been authenticated, the DHCPv6 client sends the
Encrypted-Query message to the DHCPv6 server. The Encrypted-Query Encrypted-Query message to the DHCPv6 server. The Encrypted-Query
message is constructed with the encrypted-message option, which MUST message contains the Encrypted-message option, which MUST be
be constructed as explained in Section 10.1.4, and server identifier constructed as explained in Section 10.1.3, and Server Identifier
option. The encrypted-message option contains the DHCPv6 message option. The Encrypted-message option contains the DHCPv6 message
that is encrypted using the selected server's public key. The server that is encrypted using the selected server's public key. The Server
identifier option is externally visible to avoid extra of decryption Identifier option is externally visible to avoid decryption cost by
cost by those unselected servers. those unselected servers.
The information for client authentication is contained in the For the encrypted DHCPv6 message sent from the DHCPv6 client to the
Solicit/Information-request message, which is encrypted and then DHCPv6 server, the first DHCPv6 message, such as Solicit message,
encapsulated into the Encrypted-Query message to avoid client privacy MUST contain the Certificate option for client authentication. The
disclosure. The Solicit/Information-request message MUST contain the Certificate option MUST be constructed as explained in
certificate option, which MUST be constructed as explained in Section 10.1.1. If the client have multiple certificate with
Section 10.1.1. In addition, one and only one signature option MUST different public/private key pairs, the message transaction-id is
be contained, which MUST be constructed as explained in used as the identifier of the client's private key for decryption.
Section 10.1.2. It protects the message header and all DHCPv6 In addition, the encrypted DHCPv6 message can contain the timestamp
options except for the Authentication Option. One and only one option to defend against replay attacks. The timestamp option MUST
Timestamp option, which MUST be constructed as explained in be constructed as explained in Section 10.1.2.
Section 10.1.3. The Timestamp field SHOULD be set to the current
time, according to sender's real time clock.
For the received Encrypted-Response message, the client extracts the For the received Encrypted-Response message, the client extracts the
encrypted-message option and decrypts it using its private key to Encrypted-message option and decrypts it using its private key to
obtain the original DHCPv6 message. Then it handles the message as obtain the original DHCPv6 message. Then it handles the message as
per [RFC3315]. If the client fails to get the proper parameters from per [RFC3315]. If the decrypted DHCPv6 message contains the
the chosen server, it sends the Encrypted-Query message to another timestamp option, the DHCPv6 client checks the timestamp according to
authenticated server for parameters configuration until the client the rule defined in Section 9.1. The DHCPv6 message, which fails the
obtains the proper parameters. timestamp check, MUST be discarded. If the client fails to get the
proper parameters from the chosen server, it sends the Encrypted-
Query message to another authenticated server for parameters
configuration until the client obtains the proper parameters.
When the client receives a Reply message with an error status code, When the client receives a Reply message with an error status code,
the error status code indicates the failure reason on the server the error status code indicates the failure reason on the server
side. According to the received status code, the client MAY take side. According to the received status code, the client MAY take
follow-up action: follow-up action:
o Upon receiving an AlgorithmNotSupported error status code, the o Upon receiving an AlgorithmNotSupported error status code, the
client SHOULD resend the message protected with one of the client SHOULD resend the message protected with one of the
mandatory algorithms. mandatory algorithms.
o Upon receiving an AuthenticationFail error status code, the client o Upon receiving an AuthenticationFail error status code, the client
is not able to build up the secure communication with the is not able to build up the secure communication with the server.
recipient. However, there may be other DHCPv6 servers available However, there may be other DHCPv6 servers available that
that successfully complete authentication. The client MAY use the successfully complete authentication. The client MAY use the
AuthenticationFail as a hint and switch to other public key AuthenticationFail as a hint and switch to other certificate if it
certificate if it has another one; but otherwise treat the message has another one; but otherwise treat the message containing the
containing the status code as if it had not been received. But it status code as if it had not been received. But it SHOULD NOT
SHOULD NOT retry with the same certificate. However, if the retry with the same certificate. However, if the client decides
client decides to retransmit using the same certificate after to retransmit using the same certificate after receiving
receiving AuthenticationFail, it MUST NOT retransmit immediately AuthenticationFail, it MUST NOT retransmit immediately and MUST
and MUST follow normal retransmission routines defined in follow normal retransmission routines defined in [RFC3315].
[RFC3315].
o Upon receiving a DecryptionFail error status code, the client MAY
resend the message following normal retransmission routines
defined in [RFC3315].
o Upon receiving a TimestampFail error status code, the client MAY o Upon receiving a TimestampFail error status code, the client MAY
resend the message with an adjusted timestamp according to the resend the message with an adjusted timestamp according to the
returned clock from the DHCPv6 server. The client SHOULD NOT returned clock from the DHCPv6 server. The client SHOULD NOT
change its own clock, but only compute an offset for the change its own clock, but only compute an offset for the
communication session. communication session.
o Upon receiving a SignatureFail error status code, the client MAY
resend the message following normal retransmission routines
defined in [RFC3315].
7. DHCPv6 Server Behavior 7. DHCPv6 Server Behavior
For the secure DHCPv6 server, it also MUST have a public certificate. For the secure DHCPv6 server, a certificate is need for server
The server may be pre-configured a public key certificate, which is authentication. The server is pre-configured with a certificate and
signed by a CA trusted by the server, and its corresponding private its corresponding private key. If the server is pre-configured with
key. public key not certificate, it can generate the self-signed
certificate for server authentication.
When the DHCPv6 server receives the Information-request message and When the DHCPv6 server receives the Information-request message and
the contained Option Request option informs the request for the the contained Option Request option identifies the request is for the
server authentication information, it replies the Reply message to server certificate information, it replies with a Reply message to
the client. The reply message MUST contain the requested certificate the client. The Reply message MUST contain the requested Certificate
option, which MUST be constructed as explained in Section 10.1.1. In option, which MUST be constructed as explained in Section 10.1.1, and
addition, the Reply message MUST contain one and only one Signature Server Identifier option.
option, which MUST be constructed as explained in Section 10.1.2. It
protects the message header and all DHCPv6 options except for the
Authentication Option. Besides, the Reply message SHOULD contain one
and only one Timestamp option, which MUST be constructed as explained
in Section 10.1.3. The Timestamp field SHOULD be set to the current
time, according to server's real time clock.
Upon the receipt of Encrypted-Query message, the server checks the Upon the receipt of Encrypted-Query message, the server checks the
server identifier option. It decrypts the encrypted-message option Server Identifier option. It decrypts the Encrypted-message option
using its private key if it is the target server. The DHCPv6 server using its private key if it is the target server. The DHCPv6 server
drops the message that is not for it, thus not paying cost to decrypt drops the message that is not for it, thus not paying cost to decrypt
the message. messages not for it.
If the decrypted message is Solicit/Information-request message, the
secure DHCPv6 server SHOULD discard the received message that meet
any of the following conditions:
o the signature option is missing,
o multiple signature options are present,
o the certificate option is missing.
In such failure, the server SHOULD reply an UnspecFail (value 1,
[RFC3315]) error status code.
The server SHOULD first check the support of the hash and signature If the decrypted message is a Solicit/Information-request message,
algorithms that the client used. If the check fails, the server the secure DHCPv6 server SHOULD discard the received message if the
SHOULD reply with an AlgorithmNotSupported error status code, defined Certificate option is missing. In such failure, the server SHOULD
in Section 10.3, back to the client. If both hash and signature reply with an UnspecFail (value 1, [RFC3315]) error status code.
algorithms are supported, the server then checks the authority of
this client.
If a certificate option is provided, the server SHOULD validate the If a Certificate option is provided, the server SHOULD first check
certificate according to the rules defined in [RFC5280]. An the support of the encryption algorithm that the client used. If the
implementation may create a local trust certificate record for check fails, the server SHOULD reply with an AlgorithmNotSupported
verified certificates in order to avoid repeated verification error status code, defined in Section 10.3 back to the client. If
procedure in the future. A certificate that finds a match in the the encryption algorithm is supported, the server then checks the
local trust certificate list is treated as verified. authority of this client.
The message that fails certificate validation, MUST be dropped. In The server SHOULD validate the certificate according to the rules
such failure, the DHCPv6 server SHOULD reply an AuthenticationFail defined in [RFC5280]. An implementation may create a local trust
error status code, defined in Section 10.3, back to the client. At certificate record for verified certificates in order to avoid
this point, the server has either recognized the authentication of repeated verification procedure in the future. A certificate that
the client, or decided to drop the message. finds a match in the local trust certificate list is treated as
verified. The message that fails certificate validation MUST be
dropped. In such failure, the DHCPv6 server SHOULD reply with an
AuthenticationFail error status code, defined in Section 10.3, back
to the client. At this point, the server has either recognized the
authentication of the client, or decided to drop the message.
If the server does not send the timestamp option, the client ignores If the decrypted message contains the timestamp option, the server
the timestamp check and verifies the signature. If there is a checks the timestamp according to the rule defined in Section 9.1.
timestamp option, the server MUST now authenticate the client by If the timestamp check fails, a TimestampFail error status code,
verifying the signature and checking timestamp (see details in defined in Section 10.3, should be sent back to the client.
Section 9.1). The order of two procedures is left as an
implementation decision. It is RECOMMENDED to check timestamp first,
because signature verification is much more computationally
expensive. Depending on server's local policy, the message without a
Timestamp option MAY be acceptable or rejected. If the server
rejects such a message, a TimestampFail error status code, defined in
Section 10.3, should be sent back to the client. The reply message
that carries the TimestampFail error status code SHOULD carry a
timestamp option, which indicates the server's clock for the client
to use.
The signature field verification MUST show that the signature has Depending on server's local policy, the message without a Timestamp
been calculated as specified in Section 10.1.2. Only the clients option MAY be acceptable or rejected. If the server rejects such a
that get through both the signature verification and timestamp check message, a TimestampFail error status code should be sent back to the
(if there is a Timestamp option) are accepted as authenticated client. The Reply message that carries the TimestampFail error
clients and continue to be handled their message as defined in status code SHOULD carry a timestamp option, which indicates the
[RFC3315]. Clients that do not pass the above tests MUST be treated server's clock for the client to use.
as unauthenticated clients. The DHCPv6 server SHOULD reply a
SignatureFail error status code, defined in Section 10.3, for the
signature verification failure; or a TimestampFail error status code,
defined in Section 10.3, for the timestamp check failure, back to the
client.
Once the client has been authenticated, the DHCPv6 server sends the Once the client has been authenticated, the DHCPv6 server sends the
Encrypted-response message to the DHCPv6 client. The Encrypted- Encrypted-response message to the DHCPv6 client. The Encrypted-
response message contains the encrypted-message option, which MUST be response message contains the Encrypted-message option, which MUST be
constructed as explained in Section 10.1.4. The encrypted-message constructed as explained in Section 10.1.3. The Encrypted-message
option contains the encrypted DHCPv6 message that is encrypted using option contains the encrypted DHCPv6 message that is encrypted using
the authenticated client's public key. the authenticated client's public key. To provide the replay
protection, the timestamp option can be contained in the encrypted
DHCPv6 message.
8. Relay Agent Behavior 8. Relay Agent Behavior
When a DHCPv6 relay agent receives an Encrypted-query or Encrypted- When a DHCPv6 relay agent receives an Encrypted-query or Encrypted-
response message, it may not recognize this message. The unknown response message, it may not recognize this message. The unknown
messages MUST be forwarded as describes in [RFC7283]. messages MUST be forwarded as described in [RFC7283].
When a DHCPv6 relay agent recognizes the Encrypted-query and When a DHCPv6 relay agent recognizes the Encrypted-query and
Encrypted-response messages, it forwards the message according to Encrypted-response messages, it forwards the message according to
section 20 of [RFC3315]. There is nothing more the relay agents have section 20 of [RFC3315]. There is nothing more the relay agents have
to do, it neither needs to verify the messages from client or server, to do, it neither needs to verify the messages from client or server,
nor add any secure DHCPv6 options. Actually, by definition in this nor add any secure DHCPv6 options. Actually, by definition in this
document, relay agents SHOULD NOT add any secure DHCPv6 options. document, relay agents MUST NOT add any secure DHCPv6 options.
Relay-forward and Relay-reply messages MUST NOT contain any Relay-forward and Relay-reply messages MUST NOT contain any
additional certificate option or signature Option or timestamp additional Certificate option or Timestamp option, aside from those
Option, aside from those present in the innermost encapsulated present in the innermost encapsulated messages from the client or
messages from the client or server. server.
9. Processing Rules 9. Processing Rules
9.1. Timestamp Check 9.1. Timestamp Check
In order to check the Timestamp option, defined in Section 10.1.3, In order to check the Timestamp option, defined in Section 10.1.2,
recipients SHOULD be configured with an allowed timestamp Delta recipients SHOULD be configured with an allowed timestamp Delta
value, a "fuzz factor" for comparisons, and an allowed clock drift value, a "fuzz factor" for comparisons, and an allowed clock drift
parameter. The recommended default value for the allowed Delta is parameter. The recommended default value for the allowed Delta is
300 seconds (5 minutes); for fuzz factor 1 second; and for clock 300 seconds (5 minutes); for fuzz factor 1 second; and for clock
drift, 0.01 second. drift, 0.01 second.
Note: the Timestamp mechanism is based on the assumption that Note: the Timestamp mechanism is based on the assumption that
communication peers have roughly synchronized clocks, with certain communication peers have roughly synchronized clocks, within certain
allowed clock drift. So, accurate clock is not necessary. If one allowed clock drift. So, an accurate clock is not necessary. If one
has a clock too far from the current time, the timestamp mechanism has a clock too far from the current time, the timestamp mechanism
would not work. would not work.
To facilitate timestamp checking, each recipient SHOULD store the To facilitate timestamp checking, each recipient SHOULD store the
following information for each sender, from which at least one following information for each sender, from which at least one
accepted secure DHCPv6 message is successfully verified (for both accepted secure DHCPv6 message is successfully verified (for
timestamp check and signature verification): timestamp check):
o The receive time of the last received and accepted DHCPv6 message. o The receive time of the last received and accepted DHCPv6 message.
This is called RDlast. This is called RDlast.
o The timestamp in the last received and accepted DHCPv6 message. o The timestamp in the last received and accepted DHCPv6 message.
This is called TSlast. This is called TSlast.
A verified (for both timestamp check and signature verification) A verified (for timestamp check) secure DHCPv6 message initiates the
secure DHCPv6 message initiates the update of the above variables in update of the above variables in the recipient's record.
the recipient's record.
Recipients MUST check the Timestamp field as follows: Recipients MUST check the Timestamp field as follows:
o When a message is received from a new peer (i.e., one that is not o When a message is received from a new peer (i.e., one that is not
stored in the cache), the received timestamp, TSnew, is checked, stored in the cache), the received timestamp, TSnew, is checked,
and the message is accepted if the timestamp is recent enough to and the message is accepted if the timestamp is recent enough to
the reception time of the packet, RDnew: the reception time of the packet, RDnew:
-Delta < (RDnew - TSnew) < +Delta -Delta < (RDnew - TSnew) < +Delta
skipping to change at page 15, line 36 skipping to change at page 14, line 16
entries. The specific policy as to which entries are preferred over entries. The specific policy as to which entries are preferred over
others is left as an implementation decision. others is left as an implementation decision.
An implementation MAY statefully record the latest timestamps from An implementation MAY statefully record the latest timestamps from
senders. In such implementation, the timestamps MUST be strictly senders. In such implementation, the timestamps MUST be strictly
monotonously increasing. This is reasonable given that DHCPv6 monotonously increasing. This is reasonable given that DHCPv6
messages are rarely misordered. messages are rarely misordered.
10. Extensions for Secure DHCPv6 10. Extensions for Secure DHCPv6
This section describes the extensions to DHCPv6. Five new DHCPv6 This section describes the extensions to DHCPv6. Three new DHCPv6
options, two new DHCPv6 messages and five status codes are defined. options, two new DHCPv6 messages and four status codes are defined.
10.1. New DHCPv6 Options 10.1. New DHCPv6 Options
10.1.1. Certificate Option 10.1.1. Certificate Option
The certificate option carries the public key certificate of the The Certificate option carries the certificate of the client/server.
client/server. The format of the certificate option is described as The format of the Certificate option is described as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_CERTIFICATE | option-len | | OPTION_CERTIFICATE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | EA-id | |
. Certificate (variable length) . +-+-+-+-+-+-+-+-+ .
. Certificate (variable length) .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_CERTIFICATE (TBA1). option-code OPTION_CERTIFICATE (TBA1).
option-len Length of certificate in octets. option-len 1 + Length of certificate in octets.
EA-id Encryption Algorithm id. The encryption algorithm
is used for the encrypted DHCPv6 configuration
process. This design is adopted in order to provide
encryption algorithm agility. The value is from the
Encryption Algorithm for Secure DHCPv6 registry in
IANA. A registry of the initial assigned values
is defined in Section 12.
Certificate A variable-length field containing certificate. The Certificate A variable-length field containing certificate. The
encoding of certificate and certificate data MUST encoding of certificate and certificate data MUST
be in format as defined in Section 3.6, [RFC7296]. be in format as defined in Section 3.6, [RFC7296].
The support of X.509 certificate - Signature (4) The support of X.509 certificate is mandatory.
is mandatory.
10.1.2. Signature Option
The signature option allows a signature that is signed by the private
key to be attached to a DHCPv6 message. The signature option could
be any place within the DHCPv6 message while it is logically created
after the entire DHCPv6 header and options, except for the
Authentication Option. It protects the entire DHCPv6 header and
options, including itself, except for the Authentication Option. The
format of the Signature option is described as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_SIGNATURE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HA-id | SA-id | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
. Signature (variable length) .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_SIGNATURE (TBA2).
option-len 2 + Length of Signature field in octets.
HA-id Hash Algorithm id. The hash algorithm is used for
computing the signature result. This design is
adopted in order to provide hash algorithm agility.
The value is from the Hash Algorithm for Secure
DHCPv6 registry in IANA. The support of SHA-256 is
mandatory. A registry of the initial assigned values
is defined in Section 8.
SA-id Signature Algorithm id. The signature algorithm is
used for computing the signature result. This
design is adopted in order to provide signature
algorithm agility. The value is from the Signature
Algorithm for Secure DHCPv6 registry in IANA. The
support of RSASSA-PKCS1-v1_5 is mandatory. A
registry of the initial assigned values is defined
in Section 8.
Signature A variable-length field containing a digital
signature. The signature value is computed with
the hash algorithm and the signature algorithm,
as described in HA-id and SA-id. The signature
constructed by using the sender's private key
protects the following sequence of octets:
1. The DHCPv6 message header.
2. All DHCPv6 options including the Signature
option (fill the signature field with zeroes)
except for the Authentication Option.
The signature field MUST be padded, with all 0, to
the next octet boundary if its size is not a
multiple of 8 bits. The padding length depends on
the signature algorithm, which is indicated in the
SA-id field.
Note: if both signature and authentication option are present,
signature option does not protect the Authentication Option. It
allows the Authentication Option be created after signature has been
calculated and filled with the valid signature. It is because both
options need to apply hash algorithm to whole message, so there must
be a clear order and there could be only one last-created option.
changing auth option, the authors chose not include authentication
option in the signature.
10.1.3. Timestamp Option 10.1.2. Timestamp Option
The Timestamp option carries the current time on the sender. It adds The Timestamp option carries the current time on the sender. It adds
the anti-replay protection to the DHCPv6 messages. It is optional. the anti-replay protection to the DHCPv6 messages. It is optional.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_TIMESTAMP | option-len | | OPTION_TIMESTAMP | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Timestamp (64-bit) | | Timestamp (64-bit) |
| | | |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_TIMESTAMP (TBA3). option-code OPTION_TIMESTAMP (TBA2).
option-len 8, in octets. option-len 8, in octets.
Timestamp The current time of day (SeND-format timestamp Timestamp The current time of day (SeND-format timestamp
in UTC (Coordinated Universal Time). It can reduce in UTC (Coordinated Universal Time). It can reduce
the danger of replay attacks. the danger of replay attacks. The timestamp data MUST
be in format as defined in Section 5.3.1, [RFC3971].
10.1.4. Encrypted-message Option 10.1.3. Encrypted-message Option
The encrypted-message option carries the encrypted DHCPv6 message The Encrypted-message option carries the encrypted DHCPv6 message
with the recipient's public key. with the recipient's public key.
The format of the encrypted-message option is: The format of the Encrypted-message option is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| option-code | option-len | | option-code | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
. encrypted DHCPv6 message . . encrypted DHCPv6 message .
. (variable) . . (variable) .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: encrypted-message Option Format Figure 1: Encrypted-message Option Format
option-code OPTION_ENCRYPTED_MSG (TBA4). option-code OPTION_ENCRYPTED_MSG (TBA3).
option-len Length of the encrypted DHCPv6 message. option-len Length of the encrypted DHCPv6 message.
encrypted DHCPv6 message A variable length field containing the encrypted DHCPv6 message A variable length field containing the
encrypted DHCPv6 message sent by the client or the server. In encrypted DHCPv6 message sent by the client or the server. In
Encrypted-Query message, it contains encrypted DHCPv6 message sent Encrypted-Query message, it contains encrypted DHCPv6 message sent
by a client. In Encrypted-response message, it contains encrypted by a client. In Encrypted-response message, it contains encrypted
DHCPv6 message sent by a server. DHCPv6 message sent by a server.
10.2. New DHCPv6 Messages 10.2. New DHCPv6 Messages
10.2.1. Encrypted-Query Message Two new DHCPv6 messages are defined to achieve the DHCPv6 encryption:
Encrypted-Query and Encrypted-Response. Both the DHCPv6 messages
The Encrypted-Query message is sent from DHCPv6 client to DHCPv6 defined in this document share the following format:
server, which contains the server identifier option and encrypted-
message option.
The format of the Encrypted-Query message is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-type | transaction-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. DUID .
| (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. encrypted-message option .
. (variable) .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: The format of Encrypted-Query Message
msg-type ENCRYPTED-QUERY (TBA5)
transaction-id The transaction ID for this message exchange.
DUID The DUID for the server.
encrypted-message option The encrypted DHCPv6 message.
10.2.2. Encrypted-Response Message
The Encrypted-Response message is sent from DHCPv6 server to DHCPv6
client, which contains the encrypted-message option.
The format of the Encrypted-Response message is:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| msg-type | transaction-id | | msg-type | transaction-id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
. encrypted-message option . . options .
. (variable) . . (variable) .
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: The format of Encrypted-Response Message Figure 2: The format of Encrypted-Query and Encrypted-Response
Messages
msg-type ENCRYPTED-RESPONSE (TBA6). msg-type Identifier of the message type. It can be either
Encrypted-Query (TBA4) or DHCPv6-Response (TBA5).
transaction-id The transaction ID for this message exchange. transaction-id The transaction ID for this message exchange.
encrypted-message option The encrypted DHCPv6 message. options The Encrypted-Query message MUST contain the Server
Identifier option and Encrypted-message option. The
Encrypted-Response message MUST contain the
Encrypted-message option.
10.3. Status Codes 10.3. Status Codes
The following new status codes, see Section 5.4 of [RFC3315] are The following new status codes, see Section 5.4 of [RFC3315] are
defined. defined.
o AlgorithmNotSupported (TBD7): indicates that the DHCPv6 server o AlgorithmNotSupported (TBD6): indicates that the DHCPv6 server
does not support algorithms that sender used. does not support algorithms that sender used.
o AuthenticationFail (TBD8): indicates that the DHCPv6 client fails o AuthenticationFail (TBD7): indicates that the DHCPv6 client fails
authentication check. authentication check.
o TimestampFail (TBD9): indicates the message from DHCPv6 client o TimestampFail (TBD8): indicates the message from DHCPv6 client
fails the timestamp check. fails the timestamp check.
o SignatureFail (TBD10): indicates the message from DHCPv6 client o DecryptionFail (TBD9): indicates the message from DHCPv6 client
fails the signature check. fails the DHCPv6 message decryption.
11. Security Considerations 11. Security Considerations
This document provides the authentication and encryption mechanisms This document provides the authentication and encryption mechanisms
for DHCPv6. for DHCPv6.
[RFC6273] has analyzed possible threats to the hash algorithms used
in SEND. Since the Secure DHCPv6 defined in this document uses the
same hash algorithms in similar way to SEND, analysis results could
be applied as well: current attacks on hash functions do not
constitute any practical threat to the digital signatures used in the
signature algorithm in the Secure DHCPv6.
A server, whose local policy accepts messages without a Timestamp A server, whose local policy accepts messages without a Timestamp
option, may have to face the risk of replay attacks. option, may have to face the risk of replay attacks.
A window of vulnerability for replay attacks exists until the A window of vulnerability for replay attacks exists until the
timestamp expires. Secure DHCPv6 nodes are protected against replay timestamp expires. Secure DHCPv6 nodes are protected against replay
attacks as long as they cache the state created by the message attacks as long as they cache the state created by the message
containing the timestamp. The cached state allows the node to containing the timestamp. The cached state allows the node to
protect itself against replayed messages. However, once the node protect itself against replayed messages. However, once the node
flushes the state for whatever reason, an attacker can re-create the flushes the state for whatever reason, an attacker can re-create the
state by replaying an old message while the timestamp is still valid. state by replaying an old message while the timestamp is still valid.
skipping to change at page 21, line 30 skipping to change at page 18, line 38
Attacks against time synchronization protocols such as NTP [RFC5905] Attacks against time synchronization protocols such as NTP [RFC5905]
may cause Secure DHCPv6 nodes to have an incorrect timestamp value. may cause Secure DHCPv6 nodes to have an incorrect timestamp value.
This can be used to launch replay attacks, even outside the normal This can be used to launch replay attacks, even outside the normal
window of vulnerability. To protect against these attacks, it is window of vulnerability. To protect against these attacks, it is
recommended that Secure DHCPv6 nodes keep independently maintained recommended that Secure DHCPv6 nodes keep independently maintained
clocks or apply suitable security measures for the time clocks or apply suitable security measures for the time
synchronization protocols. synchronization protocols.
12. IANA Considerations 12. IANA Considerations
This document defines five new DHCPv6 [RFC3315] options. The IANA is This document defines three new DHCPv6 [RFC3315] options. The IANA
requested to assign values for these five options from the DHCPv6 is requested to assign values for these three options from the DHCPv6
Option Codes table of the DHCPv6 Parameters registry maintained in Option Codes table of the DHCPv6 Parameters registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters. The five options http://www.iana.org/assignments/dhcpv6-parameters. The three options
are: are:
The Certificate Option (TBA1), described in Section 10.1.1. The Certificate option (TBA1), described in Section 10.1.1.
The Signature Option (TBA2), described in Section 10.1.2.
The Timestamp Option (TBA3),described in Section 10.1.3. The Timestamp option (TBA2),described in Section 10.1.2.
The Encrypted-message Option (TBA4), described in Section 10.1.4. The Encrypted-message option (TBA3), described in Section 10.1.3.
The IANA is also requested to assign value for these two messages The IANA is also requested to assign value for these two messages
from the DHCPv6 Message Types table of the DHCPv6 Parameters registry from the DHCPv6 Message Types table of the DHCPv6 Parameters registry
maintained in http://www.iana.org/assignments/dhcpv6-parameters. The maintained in http://www.iana.org/assignments/dhcpv6-parameters. The
two messages are: two messages are:
The Encrypted-Query Message (TBA5), described in Section 10.2.1. The Encrypted-Query message (TBA4), described in Section 10.2.
The Encrypted-Response Message (TBA6), described in The Encrypted-Response message (TBA5), described in Section 10.2.
Section 10.2.2.
The IANA is also requested to add two new registry tables to the The IANA is also requested to add one new registry tables to the
DHCPv6 Parameters registry maintained in DHCPv6 Parameters registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters. The two tables http://www.iana.org/assignments/dhcpv6-parameters. The table is the
are the Hash Algorithm for Secure DHCPv6 table and the Signature Encryption Algorithm for Secure DHCPv6 table.
Algorithm for Secure DHCPv6 table.
Initial values for these registries are given below. Future Initial values for these registries are given below. Future
assignments are to be made through Standards Action [RFC5226]. assignments are to be made through Standards Action [RFC5226].
Assignments for each registry consist of a name, a value and a RFC Assignments for each registry consist of a name, a value and a RFC
number where the registry is defined. number where the registry is defined.
Hash Algorithm for Secure DHCPv6. The values in this table are 8-bit Encryption algorithm for Secure DHCPv6. The values in this table are
unsigned integers. The following initial values are assigned for
Hash Algorithm for Secure DHCPv6 in this document:
Name | Value | RFCs
-------------------+---------+--------------
SHA-256 | 0x01 | this document
SHA-512 | 0x02 | this document
Signature Algorithm for Secure DHCPv6. The values in this table are
8-bit unsigned integers. The following initial values are assigned 8-bit unsigned integers. The following initial values are assigned
for Signature Algorithm for Secure DHCPv6 in this document: for encryption algorithm for Secure DHCPv6 in this document:
Name | Value | RFCs Name | Value | RFCs
-------------------+---------+-------------- -------------------+---------+--------------
RSASSA-PKCS1-v1_5 | 0x01 | this document RSA | 0 | this document
IANA is requested to assign the following new DHCPv6 Status Codes, IANA is requested to assign the following new DHCPv6 Status Codes,
defined in Section 10.3, in the DHCPv6 Parameters registry maintained defined in Section 10.3, in the DHCPv6 Parameters registry maintained
in http://www.iana.org/assignments/dhcpv6-parameters: in http://www.iana.org/assignments/dhcpv6-parameters:
Code | Name | Reference Code | Name | Reference
---------+-----------------------+-------------- ---------+-----------------------+--------------
TBD7 | AlgorithmNotSupported | this document TBD6 | AlgorithmNotSupported | this document
TBD8 | AuthenticationFail | this document TBD7 | AuthenticationFail | this document
TBD9 | TimestampFail | this document TBD8 | TimestampFail | this document
TBD10 | SignatureFail | this document TBD9 | DecryptionFail | this document
13. Acknowledgements 13. Acknowledgements
The authors would like to thank Tomek Mrugalski, Bernie Volz, Randy The authors would like to thank Tomek Mrugalski, Bernie Volz,
Bush, Yiu Lee, Jianping Wu, Sean Shen, Ralph Droms, Jari Arkko, Sean Jianping Wu, Randy Bush, Yiu Lee, Sean Shen, Ralph Droms, Jari Arkko,
Turner, Stephen Farrell, Christian Huitema, Stephen Kent, Thomas Sean Turner, Stephen Farrell, Christian Huitema, Stephen Kent, Thomas
Huth, David Schumacher, Francis Dupont, Gang Chen, Suresh Krishnan, Huth, David Schumacher, Francis Dupont, Gang Chen, Suresh Krishnan,
Fred Templin, Robert Elz, Nico Williams, Erik Kline, Alan DeKok, Fred Templin, Robert Elz, Nico Williams, Erik Kline, Alan DeKok,
Bernard Aboba, Sam Hartman, Qi Sun, Zilong Liu, and other members of Bernard Aboba, Sam Hartman, Qi Sun, Zilong Liu and other members of
the IETF DHC working group for their valuable comments. the IETF DHC working group for their valuable comments.
This document was produced using the xml2rfc tool [RFC2629]. This document was produced using the xml2rfc tool [RFC2629].
14. References 14. Change log [RFC Editor: Please remove]
14.1. Normative References draft-ietf-dhc-sedhcpv6-11: Delete the Signature option, because the
encrypted DHCPv6 message and the Information-request message (only
contain the certificate option) don't need the signature option for
message integrity check; Rewrite the "Applicability" section; Add the
encryption algorithm negotiation process; To support the encryption
algorithm negotiation, the Certificate option contains the EA-
id(encryption algorithm identifier) field; Reserve the timestamp
option to defend against the replay attacks for encrypted DHCPv6
configuration process; Modify the client behavior when there is no
authenticated DHCPv6 server; Add the DecryptionFail error code.
2016-3-9.
draft-ietf-dhc-sedhcpv6-10: merge DHCPv6 authentication and DHCPv6
encryption. The public key option is removed, because the device can
generate the self-signed certificate if it is pre-configured the
public key not the certificate. 2015-12-10.
draft-ietf-dhc-sedhcpv6-09: change some texts about the deployment
part.2015-12-10.
draft-ietf-dhc-sedhcpv6-08: clarified what the client and the server
should do if it receives a message using unsupported algorithm;
refined the error code treatment regarding to AuthenticationFail and
TimestampFail; added consideration on how to reduce the DoS attack
when using TOFU; other general editorial cleanups. 2015-06-10.
draft-ietf-dhc-sedhcpv6-07: removed the deployment consideration
section; instead, described more straightforward use cases with TOFU
in the overview section, and clarified how the public keys would be
stored at the recipient when TOFU is used. The overview section also
clarified the integration of PKI or other similar infrastructure is
an open issue. 2015-03-23.
draft-ietf-dhc-sedhcpv6-06: remove the limitation that only clients
use PKI- certificates and only servers use public keys. The new text
would allow clients use public keys and servers use PKI-certificates.
2015-02-18.
draft-ietf-dhc-sedhcpv6-05: addressed comments from mail list that
responsed to the second WGLC. 2014-12-08.
draft-ietf-dhc-sedhcpv6-04: addressed comments from mail list.
Making timestamp an independent and optional option. Reduce the
serverside authentication to base on only client's certificate.
Reduce the clientside authentication to only Leaf of Faith base on
server's public key. 2014-09-26.
draft-ietf-dhc-sedhcpv6-03: addressed comments from WGLC. Added a
new section "Deployment Consideration". Corrected the Public Key
Field in the Public Key Option. Added consideration for large DHCPv6
message transmission. Added TimestampFail error code. Refined the
retransmission rules on clients. 2014-06-18.
draft-ietf-dhc-sedhcpv6-02: addressed comments (applicability
statement, redesign the error codes and their logic) from IETF89 DHC
WG meeting and volunteer reviewers. 2014-04-14.
draft-ietf-dhc-sedhcpv6-01: addressed comments from IETF88 DHC WG
meeting. Moved Dacheng Zhang from acknowledgement to be co-author.
2014-02-14.
draft-ietf-dhc-sedhcpv6-00: adopted by DHC WG. 2013-11-19.
draft-jiang-dhc-sedhcpv6-02: removed protection between relay agent
and server due to complexity, following the comments from Ted Lemon,
Bernie Volz. 2013-10-16.
draft-jiang-dhc-sedhcpv6-01: update according to review comments from
Ted Lemon, Bernie Volz, Ralph Droms. Separated Public Key/
Certificate option into two options. Refined many detailed
processes. 2013-10-08.
draft-jiang-dhc-sedhcpv6-00: original version, this draft is a
replacement of draft-ietf-dhc-secure-dhcpv6, which reached IESG and
dead because of consideration regarding to CGA. The authors followed
the suggestion from IESG making a general public key based mechanism.
2013-06-29.
15. Open Issues [RFC Editor: Please remove]
this protocol changes DHCPv6 message exchanges quite substantially:
previously, the client first sends a Solicit message, gets possibly
multiple Advertise messages, chooses the server (= sender of one of
the Advertises) that would be best for the client, and then sends a
Request to that chosen server. Now the server selection is done at
the key exchange phase (the initial Information-request and Reply
exchange), and the Solicit can be sent only to a single server. If
the client doesn't like the Advertise it could restart the whole
process, but it will be more expensive, and there's no guarantee that
other servers can provide a better Advertise.
One might argue that it's okay as "secure DHCPv6" is an "optional"
extension. But, with keeping in mind that the current IETF trend is
to make everything privacy-aware (often by making everything
encrypted), I'd personally say we should consider it to be the
standard mode of DHCPv6 operation even if users can still disable it.
From this point of view, I think we should either
o A. make the server selection behavior more compatible with the
pre-encryption protocol, or
o B. accept we give up the previous server selection feature for
privacy (after careful assessment of its effect and with clear wg
consensus), and explicitly note that. we might even have to
reflect that in rfc3315bis.
16. References
16.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <http://www.rfc-editor.org/info/rfc2119>.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460, (IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>. December 1998, <http://www.rfc-editor.org/info/rfc2460>.
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins, [RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <http://www.rfc-editor.org/info/rfc3315>. 2003, <http://www.rfc-editor.org/info/rfc3315>.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005,
<http://www.rfc-editor.org/info/rfc3971>.
[RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet [RFC4443] Conta, A., Deering, S., and M. Gupta, Ed., "Internet
Control Message Protocol (ICMPv6) for the Internet Control Message Protocol (ICMPv6) for the Internet
Protocol Version 6 (IPv6) Specification", RFC 4443, Protocol Version 6 (IPv6) Specification", RFC 4443,
DOI 10.17487/RFC4443, March 2006, DOI 10.17487/RFC4443, March 2006,
<http://www.rfc-editor.org/info/rfc4443>. <http://www.rfc-editor.org/info/rfc4443>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
skipping to change at page 24, line 5 skipping to change at page 23, line 19
[RFC7283] Cui, Y., Sun, Q., and T. Lemon, "Handling Unknown DHCPv6 [RFC7283] Cui, Y., Sun, Q., and T. Lemon, "Handling Unknown DHCPv6
Messages", RFC 7283, DOI 10.17487/RFC7283, July 2014, Messages", RFC 7283, DOI 10.17487/RFC7283, July 2014,
<http://www.rfc-editor.org/info/rfc7283>. <http://www.rfc-editor.org/info/rfc7283>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T. [RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2 Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October (IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <http://www.rfc-editor.org/info/rfc7296>. 2014, <http://www.rfc-editor.org/info/rfc7296>.
14.2. Informative References 16.2. Informative References
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
DOI 10.17487/RFC2629, June 1999, DOI 10.17487/RFC2629, June 1999,
<http://www.rfc-editor.org/info/rfc2629>. <http://www.rfc-editor.org/info/rfc2629>.
[RFC4270] Hoffman, P. and B. Schneier, "Attacks on Cryptographic [RFC4270] Hoffman, P. and B. Schneier, "Attacks on Cryptographic
Hashes in Internet Protocols", RFC 4270, Hashes in Internet Protocols", RFC 4270,
DOI 10.17487/RFC4270, November 2005, DOI 10.17487/RFC4270, November 2005,
<http://www.rfc-editor.org/info/rfc4270>. <http://www.rfc-editor.org/info/rfc4270>.
skipping to change at page 24, line 49 skipping to change at page 24, line 18
CN CN
Email: jiangsheng@huawei.com Email: jiangsheng@huawei.com
Lishan Li Lishan Li
Tsinghua University Tsinghua University
Beijing 100084 Beijing 100084
P.R.China P.R.China
Phone: +86-15201441862 Phone: +86-15201441862
Email: lilishan9248@126.com Email: lilishan48@gmail.com
Yong Cui Yong Cui
Tsinghua University Tsinghua University
Beijing 100084 Beijing 100084
P.R.China P.R.China
Phone: +86-10-6260-3059 Phone: +86-10-6260-3059
Email: yong@csnet1.cs.tsinghua.edu.cn Email: yong@csnet1.cs.tsinghua.edu.cn
Tatuya Jinmei Tatuya Jinmei
Infoblox Inc. Infoblox Inc.
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