draft-ietf-isms-dtls-tm-00.txt   draft-ietf-isms-dtls-tm-01.txt 
ISMS W. Hardaker ISMS W. Hardaker
Internet-Draft Sparta, Inc. Internet-Draft Sparta, Inc.
Intended status: Standards Track September 1, 2009 Intended status: Standards Track October 22, 2009
Expires: March 5, 2010 Expires: April 25, 2010
Transport Layer Security Transport Model for SNMP Transport Layer Security Transport Model for SNMP
draft-ietf-isms-dtls-tm-00.txt draft-ietf-isms-dtls-tm-01.txt
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. This document may contain material provisions of BCP 78 and BCP 79. This document may contain material
from IETF Documents or IETF Contributions published or made publicly from IETF Documents or IETF Contributions published or made publicly
available before November 10, 2008. The person(s) controlling the available before November 10, 2008. The person(s) controlling the
copyright in some of this material may not have granted the IETF copyright in some of this material may not have granted the IETF
Trust the right to allow modifications of such material outside the Trust the right to allow modifications of such material outside the
IETF Standards Process. Without obtaining an adequate license from IETF Standards Process. Without obtaining an adequate license from
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
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The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
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The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on March 5, 2010. This Internet-Draft will expire on April 25, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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1.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 7 1.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 7
2. The Transport Layer Security Protocol . . . . . . . . . . . . 8 2. The Transport Layer Security Protocol . . . . . . . . . . . . 8
2.1. SNMP requirements of (D)TLS . . . . . . . . . . . . . . . 8 2.1. SNMP requirements of (D)TLS . . . . . . . . . . . . . . . 8
3. How the TLSTM fits into the Transport Subsystem . . . . . . . 8 3. How the TLSTM fits into the Transport Subsystem . . . . . . . 8
3.1. Security Capabilities of this Model . . . . . . . . . . . 10 3.1. Security Capabilities of this Model . . . . . . . . . . . 10
3.1.1. Threats . . . . . . . . . . . . . . . . . . . . . . . 10 3.1.1. Threats . . . . . . . . . . . . . . . . . . . . . . . 10
3.1.2. Message Protection . . . . . . . . . . . . . . . . . . 12 3.1.2. Message Protection . . . . . . . . . . . . . . . . . . 12
3.1.3. (D)TLS Sessions . . . . . . . . . . . . . . . . . . . 13 3.1.3. (D)TLS Sessions . . . . . . . . . . . . . . . . . . . 13
3.2. Security Parameter Passing . . . . . . . . . . . . . . . . 13 3.2. Security Parameter Passing . . . . . . . . . . . . . . . . 13
3.3. Notifications and Proxy . . . . . . . . . . . . . . . . . 14 3.3. Notifications and Proxy . . . . . . . . . . . . . . . . . 14
4. Elements of the Model . . . . . . . . . . . . . . . . . . . . 15 4. Elements of the Model . . . . . . . . . . . . . . . . . . . . 14
4.1. X.509 Certificates . . . . . . . . . . . . . . . . . . . . 15 4.1. X.509 Certificates . . . . . . . . . . . . . . . . . . . . 15
4.1.1. Provisioning for the Certificate . . . . . . . . . . . 15 4.1.1. Provisioning for the Certificate . . . . . . . . . . . 15
4.2. Messages . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.2. Messages . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.3. SNMP Services . . . . . . . . . . . . . . . . . . . . . . 16 4.3. SNMP Services . . . . . . . . . . . . . . . . . . . . . . 16
4.3.1. SNMP Services for an Outgoing Message . . . . . . . . 16 4.3.1. SNMP Services for an Outgoing Message . . . . . . . . 16
4.3.2. SNMP Services for an Incoming Message . . . . . . . . 17 4.3.2. SNMP Services for an Incoming Message . . . . . . . . 17
4.4. (D)TLS Services . . . . . . . . . . . . . . . . . . . . . 18 4.4. (D)TLS Services . . . . . . . . . . . . . . . . . . . . . 18
4.4.1. Services for Establishing a Session . . . . . . . . . 18 4.4.1. Services for Establishing a Session . . . . . . . . . 18
4.4.2. (D)TLS Services for an Incoming Message . . . . . . . 20 4.4.2. (D)TLS Services for an Incoming Message . . . . . . . 19
4.4.3. (D)TLS Services for an Outgoing Message . . . . . . . 20 4.4.3. (D)TLS Services for an Outgoing Message . . . . . . . 20
4.5. Cached Information and References . . . . . . . . . . . . 21 4.5. Cached Information and References . . . . . . . . . . . . 21
4.5.1. TLS Transport Model Cached Information . . . . . . . . 21 4.5.1. TLS Transport Model Cached Information . . . . . . . . 21
5. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 21 5. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 21
5.1. Procedures for an Incoming Message . . . . . . . . . . . . 22 5.1. Procedures for an Incoming Message . . . . . . . . . . . . 22
5.1.1. DTLS Processing for Incoming Messages . . . . . . . . 22 5.1.1. DTLS Processing for Incoming Messages . . . . . . . . 22
5.1.2. Transport Processing for Incoming Messages . . . . . . 23 5.1.2. Transport Processing for Incoming Messages . . . . . . 23
5.2. Procedures for an Outgoing Message . . . . . . . . . . . . 25 5.2. Procedures for an Outgoing Message . . . . . . . . . . . . 25
5.3. Establishing a Session . . . . . . . . . . . . . . . . . . 26 5.3. Establishing a Session . . . . . . . . . . . . . . . . . . 26
5.4. Closing a Session . . . . . . . . . . . . . . . . . . . . 28 5.4. Closing a Session . . . . . . . . . . . . . . . . . . . . 28
6. MIB Module Overview . . . . . . . . . . . . . . . . . . . . . 29 6. MIB Module Overview . . . . . . . . . . . . . . . . . . . . . 29
6.1. Structure of the MIB Module . . . . . . . . . . . . . . . 29 6.1. Structure of the MIB Module . . . . . . . . . . . . . . . 29
6.2. Textual Conventions . . . . . . . . . . . . . . . . . . . 29 6.2. Textual Conventions . . . . . . . . . . . . . . . . . . . 29
6.3. Statistical Counters . . . . . . . . . . . . . . . . . . . 29 6.3. Statistical Counters . . . . . . . . . . . . . . . . . . . 29
6.4. Configuration Tables . . . . . . . . . . . . . . . . . . . 29 6.4. Configuration Tables . . . . . . . . . . . . . . . . . . . 29
6.4.1. Notifications . . . . . . . . . . . . . . . . . . . . 30
6.5. Relationship to Other MIB Modules . . . . . . . . . . . . 30 6.5. Relationship to Other MIB Modules . . . . . . . . . . . . 30
6.5.1. MIB Modules Required for IMPORTS . . . . . . . . . . . 30 6.5.1. MIB Modules Required for IMPORTS . . . . . . . . . . . 30
7. MIB Module Definition . . . . . . . . . . . . . . . . . . . . 30 7. MIB Module Definition . . . . . . . . . . . . . . . . . . . . 30
8. Operational Considerations . . . . . . . . . . . . . . . . . . 53 8. Operational Considerations . . . . . . . . . . . . . . . . . . 53
8.1. Sessions . . . . . . . . . . . . . . . . . . . . . . . . . 53 8.1. Sessions . . . . . . . . . . . . . . . . . . . . . . . . . 53
8.2. Notification Receiver Credential Selection . . . . . . . . 53 8.2. Notification Receiver Credential Selection . . . . . . . . 54
8.3. contextEngineID Discovery . . . . . . . . . . . . . . . . 54 8.3. contextEngineID Discovery . . . . . . . . . . . . . . . . 54
9. Security Considerations . . . . . . . . . . . . . . . . . . . 54 9. Security Considerations . . . . . . . . . . . . . . . . . . . 55
9.1. Certificates, Authentication, and Authorization . . . . . 54 9.1. Certificates, Authentication, and Authorization . . . . . 55
9.2. Use with SNMPv1/SNMPv2c Messages . . . . . . . . . . . . . 55 9.2. Use with SNMPv1/SNMPv2c Messages . . . . . . . . . . . . . 56
9.3. MIB Module Security . . . . . . . . . . . . . . . . . . . 56 9.3. MIB Module Security . . . . . . . . . . . . . . . . . . . 56
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 57 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 57
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 58 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 59
12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 59 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 59
12.1. Normative References . . . . . . . . . . . . . . . . . . . 59 12.1. Normative References . . . . . . . . . . . . . . . . . . . 59
12.2. Informative References . . . . . . . . . . . . . . . . . . 60 12.2. Informative References . . . . . . . . . . . . . . . . . . 61
Appendix A. (D)TLS Overview . . . . . . . . . . . . . . . . . . . 61 Appendix A. (D)TLS Overview . . . . . . . . . . . . . . . . . . . 62
A.1. The (D)TLS Record Protocol . . . . . . . . . . . . . . . . 61 A.1. The (D)TLS Record Protocol . . . . . . . . . . . . . . . . 62
A.2. The (D)TLS Handshake Protocol . . . . . . . . . . . . . . 62 A.2. The (D)TLS Handshake Protocol . . . . . . . . . . . . . . 62
Appendix B. PKIX Certificate Infrastructure . . . . . . . . . . . 63 Appendix B. PKIX Certificate Infrastructure . . . . . . . . . . . 63
Appendix C. Target and Notificaton Configuration Example . . . . 64 Appendix C. Target and Notificaton Configuration Example . . . . 64
C.1. Configuring the Notification Generator . . . . . . . . . . 65
C.2. Configuring the Command Responder . . . . . . . . . . . . 65
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 66 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 66
1. Introduction 1. Introduction
It is important to understand the modular SNMPv3 architecture as It is important to understand the modular SNMPv3 architecture as
defined by [RFC3411] and enhanced by the Transport Subsystem defined by [RFC3411] and enhanced by the Transport Subsystem
[I-D.ietf-isms-tmsm]. It is also important to understand the [RFC5590]. It is also important to understand the terminology of the
terminology of the SNMPv3 architecture in order to understand where SNMPv3 architecture in order to understand where the Transport Model
the Transport Model described in this document fits into the described in this document fits into the architecture and how it
architecture and how it interacts with the other architecture interacts with the other architecture subsystems. For a detailed
subsystems. For a detailed overview of the documents that describe overview of the documents that describe the current Internet-Standard
the current Internet-Standard Management Framework, please refer to Management Framework, please refer to Section 7 of [RFC3410].
Section 7 of [RFC3410].
This document describes a Transport Model that makes use of the This document describes a Transport Model that makes use of the
Transport Layer Security (TLS) [RFC5246] and the Datagram Transport Transport Layer Security (TLS) [RFC5246] and the Datagram Transport
Layer Security (DTLS) Protocol [RFC4347], within a transport Layer Security (DTLS) Protocol [RFC4347], within a transport
subsystem [I-D.ietf-isms-tmsm]. DTLS is the datagram variant of the subsystem [RFC5590]. DTLS is the datagram variant of the Transport
Transport Layer Security (TLS) protocol [RFC5246]. The Transport Layer Security (TLS) protocol [RFC5246]. The Transport Model in this
Model in this document is referred to as the Transport Layer Security document is referred to as the Transport Layer Security Transport
Transport Model (TLSTM). TLS and DTLS take advantage of the X.509 Model (TLSTM). TLS and DTLS take advantage of the X.509 public
public keying infrastructure [RFC5280]. This transport model is keying infrastructure [RFC5280]. This transport model is designed to
designed to meet the security and operational needs of network meet the security and operational needs of network administrators,
administrators, operate in both environments where a connectionless operate in both environments where a connectionless (e.g. UDP or
(e.g. UDP or SCTP) transport is preferred and in environments where SCTP) transport is preferred and in environments where large
large quantities of data need to be sent (e.g. over a TCP based quantities of data need to be sent (e.g. over a TCP based stream).
stream). Both TLS and DTLS integrate well into existing public Both TLS and DTLS integrate well into existing public keying
keying infrastructures. infrastructures.
This document also defines a portion of the Management Information This document also defines a portion of the Management Information
Base (MIB) for use with network management protocols. In particular Base (MIB) for use with network management protocols. In particular
it defines objects for managing the TLS Transport Model for SNMP. it defines objects for managing the TLS Transport Model for SNMP.
For a detailed overview of the documents that describe the current For a detailed overview of the documents that describe the current
Internet-Standard Management Framework, please refer to section 7 of Internet-Standard Management Framework, please refer to section 7 of
RFC [RFC3410]. RFC [RFC3410].
Managed objects are accessed via a virtual information store, termed Managed objects are accessed via a virtual information store, termed
the Management Information Base or MIB. MIB objects are generally the Management Information Base or MIB. MIB objects are generally
accessed through the Simple Network Management Protocol (SNMP). accessed through the Simple Network Management Protocol (SNMP).
Objects in the MIB are defined using the mechanisms defined in the Objects in the MIB are defined using the mechanisms defined in the
Structure of Management Information (SMI). This memo specifies a MIB Structure of Management Information (SMI). This memo specifies a MIB
module that is compliant to the SMIv2, which is described in STD 58, module that is compliant to the SMIv2, which is described in STD 58:
[RFC2578] , STD 58, [RFC2579] and STD 58, [RFC2580] [RFC2578], [RFC2579] and [RFC2580].
The diagram shown below gives a conceptual overview of two SNMP The diagram shown below gives a conceptual overview of two SNMP
entities communicating using the TLS Transport Model. One entity entities communicating using the TLS Transport Model. One entity
contains a Command Responder and Notification Originator application, contains a Command Responder and Notification Originator application,
and the other a Command Generator and Notification Responder and the other a Command Generator and Notification Responder
application. It should be understood that this particular mix of application. It should be understood that this particular mix of
application types is an example only and other combinations are application types is an example only and other combinations are
equally as legitimate. equally as legitimate.
+----------------------------------------------------------------+ +----------------------------------------------------------------+
| Network | | Network |
+----------------------------------------------------------------+ +----------------------------------------------------------------+
^ ^ ^ ^ ^ | ^ |
|Notifications |Commands |Commands |Notifications |Notifications |Commands |Commands |Notifications
+---|---------------------|--------+ +--|---------------|-------------+ +---|---------------------|--------+ +--|---------------|-------------+
| V V | | V V | | | V | | | V |
| +------------+ +------------+ | | +-----------+ +----------+ | | +------------+ +------------+ | | +-----------+ +----------+ |
| | (D)TLS | | (D)TLS | | | | (D)TLS | | (D)TLS | | | | (D)TLS | | (D)TLS | | | | (D)TLS | | (D)TLS | |
| | Service | | Service | | | | Service | | Service | | | | Service | | Service | | | | Service | | Service | |
| | (Client) | | (Server) | | | | (Client) | | (Server)| | | | (Client) | | (Server) | | | | (Client) | | (Server)| |
| +------------+ +------------+ | | +-----------+ +----------+ | | +------------+ +------------+ | | +-----------+ +----------+ |
| ^ ^ | | ^ ^ | | ^ ^ | | ^ ^ |
| | | | | | | | | | | | | | | |
| +--+----------+ | | +-+--------------+ | | +--+----------+ | | +-+--------------+ |
| +-----|---------+----+ | | +---|--------+----+ | | +-----|---------+----+ | | +---|--------+----+ |
| | V |LCD | +-------+ | | | V |LCD | +--------+ | | | V |LCD | +-------+ | | | V |LCD | +--------+ |
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roles depending on the SNMP application types supported in the roles depending on the SNMP application types supported in the
implementation. Where distinction is required, the application names implementation. Where distinction is required, the application names
of Command Generator, Command Responder, Notification Originator, of Command Generator, Command Responder, Notification Originator,
Notification Receiver, and Proxy Forwarder are used. See "SNMP Notification Receiver, and Proxy Forwarder are used. See "SNMP
Applications" [RFC3413] for further information. Applications" [RFC3413] for further information.
Throughout this document, the terms "client" and "server" are used to Throughout this document, the terms "client" and "server" are used to
refer to the two ends of the (D)TLS transport connection. The client refer to the two ends of the (D)TLS transport connection. The client
actively opens the (D)TLS connection, and the server passively actively opens the (D)TLS connection, and the server passively
listens for the incoming (D)TLS connection. Either SNMP entity may listens for the incoming (D)TLS connection. Either SNMP entity may
act as client or as server, as discussed further below. act as client or as server.
The User-Based Security Model (USM) [RFC3414] is a mandatory-to- The User-Based Security Model (USM) [RFC3414] is a mandatory-to-
implement Security Model in STD 62. While (D)TLS and USM frequently implement Security Model in STD 62. While (D)TLS and USM frequently
refer to a user, the terminology preferred in RFC3411 [RFC3411] and refer to a user, the terminology preferred in RFC3411 and in this
in this memo is "principal". A principal is the "who" on whose memo is "principal". A principal is the "who" on whose behalf
behalf services are provided or processing takes place. A principal services are provided or processing takes place. A principal can be,
can be, among other things, an individual acting in a particular among other things, an individual acting in a particular role; a set
role; a set of individuals, with each acting in a particular role; an of individuals, with each acting in a particular role; an application
application or a set of applications, or a combination of these or a set of applications, or a combination of these within an
within an administrative domain. administrative domain.
Throughout this document, the term "session" is used to refer to a Throughout this document, the term "session" is used to refer to a
secure association between two TLS Transport Models that permits the secure association between two TLS Transport Models that permits the
transmission of one or more SNMP messages within the lifetime of the transmission of one or more SNMP messages within the lifetime of the
session. session.
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]. document are to be interpreted as described in [RFC2119].
2. The Transport Layer Security Protocol 2. The Transport Layer Security Protocol
(D)TLS provides authentication, data message integrity, and privacy (D)TLS provides authentication, data message integrity, and privacy
at the transport layer. (See [RFC4347]) at the transport layer. (See [RFC4347])
The primary goals of the TLS Transport Model are to provide privacy, The primary goals of the TLS Transport Model are to provide privacy,
source authentication and data integrity between two communicating source authentication and data integrity between two communicating
SNMP entities. The TLS and DTLS protocols provide a secure transport SNMP entities. The TLS and DTLS protocols provide a secure transport
upon which the TLSTM is based. An overview of (D)TLS can be found in upon which the TLSTM is based. An overview of (D)TLS can be found in
section Appendix A. Please refer to [RFC4347] for a complete section Appendix A. Please refer to [RFC5246] and [RFC4347] for
description of the protocol. complete descriptions of the protocols.
2.1. SNMP requirements of (D)TLS 2.1. SNMP requirements of (D)TLS
To properly support the SNMP over TLS Transport Model, the (D)TLS To properly support the SNMP over TLS Transport Model, the (D)TLS
implementation requires the following: implementation requires the following:
o The TLS Transport Model SHOULD always use authentication of both o The TLS Transport Model SHOULD always use authentication of both
the server and the client. the server and the client.
o At a minimum the TLS Transport Model MUST support authentication o At a minimum the TLS Transport Model MUST support authentication
of the Command Generator principals to guarantee the authenticity of the Command Generator, Notification Originator and Proxy
of the securityName. Forwarder principals to guarantee the authenticity of the
securityName.
o The TLS Transport Model SHOULD support the message encryption to o The TLS Transport Model SHOULD support the message encryption to
protect sensitive data from eavesdropping attacks. protect sensitive data from eavesdropping attacks.
3. How the TLSTM fits into the Transport Subsystem 3. How the TLSTM fits into the Transport Subsystem
A transport model is a component of the Transport Subsystem. The TLS A transport model is a component of the Transport Subsystem. The TLS
Transport Model thus fits between the underlying (D)TLS transport Transport Model thus fits between the underlying (D)TLS transport
layer and the message dispatcher [RFC3411] component of the SNMP layer and the message dispatcher [RFC3411] component of the SNMP
engine and the Transport Subsystem. engine and the Transport Subsystem.
skipping to change at page 11, line 16 skipping to change at page 11, line 16
operations unauthorized for a given principal may be attempted by operations unauthorized for a given principal may be attempted by
assuming the identity of another principal that has the assuming the identity of another principal that has the
appropriate authorizations. appropriate authorizations.
The TLSTM provides for authentication of the Command Generator, The TLSTM provides for authentication of the Command Generator,
Command Responder, Notification Generator, Notification Responder Command Responder, Notification Generator, Notification Responder
and Proxy Forwarder through the use of X.509 certificates. and Proxy Forwarder through the use of X.509 certificates.
The masquerade threat can be mitigated against by using an The masquerade threat can be mitigated against by using an
appropriate Access Control Model (ACM) such as the View-based appropriate Access Control Model (ACM) such as the View-based
Access Control Module (VACM) [RFC3415]. In addition, it is Access Control Module (VACM) [RFC3415].
important to authenticate and verify both the authenticated
identity of the (D)TLS client and the (D)TLS server to protect
against this threat. (See Section 9 for more detail.)
3. Message stream modification - The re-ordering, delay or replay of 3. Message stream modification - The re-ordering, delay or replay of
messages can and does occur through the natural operation of many messages can and does occur through the natural operation of many
connectionless transport services. The message stream connectionless transport services. The message stream
modification threat is the danger that messages may be modification threat is the danger that messages may be
maliciously re-ordered, delayed or replayed to an extent which is maliciously re-ordered, delayed or replayed to an extent which is
greater than can occur through the natural operation of greater than can occur through the natural operation of
connectionless transport services, in order to effect connectionless transport services, in order to effect
unauthorized management operations. unauthorized management operations.
(D)TLS provides replay protection with a MAC that includes a (D)TLS provides replay protection with a MAC that includes a
sequence number. Since UDP provides no sequencing ability DTLS sequence number. Since UDP provides no sequencing ability DTLS
uses a sliding window protocol with the sequence number for uses a sliding window protocol with the sequence number for
replay protection, see [RFC4347]. The technique used is similar replay protection (see [RFC4347]).
to that as in IPsec AH/ESP [RFC4302] [RFC4303], by maintaining a
bitmap window of received records. Records that are too old to
fit in the window and records that have previously been received
are silently discarded. The replay detection feature is
optional, since packet duplication can also occur naturally due
to routing errors and does not necessarily indicate an active
attack. Applications may conceivably detect duplicate packets
and accordingly modify their data transmission strategy.
4. Disclosure - The disclosure threat is the danger of eavesdropping 4. Disclosure - The disclosure threat is the danger of eavesdropping
on the exchanges between SNMP engines. Protecting against this on the exchanges between SNMP engines.
threat may be required by local policy at the deployment site.
Symmetric cryptography (e.g., AES [AES], DES [DES] etc.) can be Symmetric cryptography (e.g., [AES], [DES] etc.) can be used by
used by (D)TLS for data privacy. The keys for this symmetric (D)TLS for data privacy. The keys for this symmetric encryption
encryption are generated uniquely for each session and are based are generated uniquely for each session and are based on a secret
on a secret negotiated by another protocol (such as the (D)TLS negotiated by another protocol (such as the (D)TLS Handshake
Handshake Protocol). Protocol).
5. Denial of Service - the RFC 3411 architecture [RFC3411] states 5. Denial of Service - the RFC 3411 architecture [RFC3411] states
that denial of service (DoS) attacks need not be addressed by an that denial of service (DoS) attacks need not be addressed by an
SNMP security protocol. However, datagram-based security SNMP security protocol. However, datagram-based security
protocols like DTLS are susceptible to a variety of denial of protocols like DTLS are susceptible to a variety of denial of
service attacks because it is more vulnerable to spoofed service attacks because it is more vulnerable to spoofed
messages. messages.
In order to counter both of these attacks, DTLS borrows the In order to counter these attacks, DTLS borrows the stateless
stateless cookie technique used by Photuris [RFC2522] and IKEv2 cookie technique used by Photuris [RFC2522] and IKEv2 [RFC4306]
[RFC4306] and is described fully in section 4.2.1 of [RFC4347]. and is described fully in section 4.2.1 of [RFC4347]. This
This mechanism, though, does not provide any defense against mechanism, though, does not provide any defense against denial of
denial of service attacks mounted from valid IP addresses. DTLS service attacks mounted from valid IP addresses. DTLS Transport
Transport Model server implementations MUST support DTLS cookies. Model server implementations MUST support DTLS cookies.
Implementations are not required to perform the stateless cookie Implementations are not required to perform the stateless cookie
exchange for every DTLS handshakes but in environments where exchange for every DTLS handshakes but in environments where
amplification could be an issue or has been detected it is amplification could be an issue or has been detected it is
RECOMMENDED that the cookie exchange is utilized. RECOMMENDED that the cookie exchange is utilized.
See Section 9 for more detail on the security considerations
associated with the DTLSTM and these security threats.
3.1.2. Message Protection 3.1.2. Message Protection
The RFC 3411 architecture recognizes three levels of security: The RFC 3411 architecture recognizes three levels of security:
o without authentication and without privacy (noAuthNoPriv) o without authentication and without privacy (noAuthNoPriv)
o with authentication but without privacy (authNoPriv) o with authentication but without privacy (authNoPriv)
o with authentication and with privacy (authPriv) o with authentication and with privacy (authPriv)
The TLS Transport Model determines from (D)TLS the identity of the The TLS Transport Model determines from (D)TLS the identity of the
authenticated principal, and the type and address associated with an authenticated principal, and the type and address associated with an
incoming message, and the TLS Transport Model provides this incoming message. The TLS Transport Model provides this information
information to (D)TLS for an outgoing message. to (D)TLS for an outgoing message.
When an application requests a session for a message, through the When an application requests a session for a message, through the
cache, the application requests a security level for that session. cache, the application requests a security level for that session.
The TLS Transport Model MUST ensure that the (D)TLS session provides The TLS Transport Model MUST ensure that the (D)TLS session provides
security at least as high as the requested level of security. How security at least as high as the requested level of security. How
the security level is translated into the algorithms used to provide the security level is translated into the algorithms used to provide
data integrity and privacy is implementation-dependent. However, the data integrity and privacy is implementation-dependent. However, the
NULL integrity and encryption algorithms MUST NOT be used to fulfill NULL integrity and encryption algorithms MUST NOT be used to fulfill
security level requests for authentication or privacy. security level requests for authentication or privacy.
Implementations MAY choose to force (D)TLS to only allow Implementations MAY choose to force (D)TLS to only allow
cipher_suites that provide both authentication and privacy to cipher_suites that provide both authentication and privacy to
guarantee this assertion. guarantee this assertion.
If a suitable interface between the TLS Transport Model and the If a suitable interface between the TLS Transport Model and the
(D)TLS Handshake Protocol is implemented to allow the selection of (D)TLS Handshake Protocol is implemented to allow the selection of
security level dependent algorithms, for example a security level to security level dependent algorithms (for example a security level to
cipher_suites mapping table, then different security levels may be cipher_suites mapping table) then different security levels may be
utilized by the application. However, different port numbers will utilized by the application.
need to be used by at least one side of the connection to
differentiate between the (D)TLS sessions. This is the only way to
ensured proper selection of a session ID for an incoming (D)TLS
message.
The authentication, integrity and privacy algorithms used by the The authentication, integrity and privacy algorithms used by the
(D)TLS Protocol [RFC4347] may vary over time as the science of (D)TLS Protocols may vary over time as the science of cryptography
cryptography continues to evolve and the development of (D)TLS continues to evolve and the development of (D)TLS continues over
continues over time. Implementers are encouraged to plan for changes time. Implementers are encouraged to plan for changes in operator
in operator trust of particular algorithms and implementations should trust of particular algorithms and implementations should offer
offer configuration settings for mapping algorithms to SNMPv3 configuration settings for mapping algorithms to SNMPv3 security
security levels. levels.
3.1.3. (D)TLS Sessions 3.1.3. (D)TLS Sessions
(D)TLS sessions are opened by the TLS Transport Model during the (D)TLS sessions are opened by the TLS Transport Model during the
elements of procedure for an outgoing SNMP message. Since the sender elements of procedure for an outgoing SNMP message. Since the sender
of a message initiates the creation of a (D)TLS session if needed, of a message initiates the creation of a (D)TLS session if needed,
the (D)TLS session will already exist for an incoming message. the (D)TLS session will already exist for an incoming message.
Implementations MAY choose to instantiate (D)TLS sessions in Implementations MAY choose to instantiate (D)TLS sessions in
anticipation of outgoing messages. This approach might be useful to anticipation of outgoing messages. This approach might be useful to
ensure that a (D)TLS session to a given target can be established ensure that a (D)TLS session to a given target can be established
before it becomes important to send a message over the (D)TLS before it becomes important to send a message over the (D)TLS
session. Of course, there is no guarantee that a pre-established session. Of course, there is no guarantee that a pre-established
session will still be valid when needed. session will still be valid when needed.
DTLS sessions, when used over UDP, are uniquely identified within the DTLS sessions, when used over UDP, are uniquely identified within the
TLS Transport Model by the combination of transportDomain, TLS Transport Model by the combination of transportDomain,
transportAddress, securityName, and requestedSecurityLevel associated transportAddress, securityName, and requestedSecurityLevel associated
with each session. Each unique combination of these parameters MUST with each session. Each unique combination of these parameters MUST
have a locally-chosen unique dtlsSessionID associated for active have a locally-chosen unique tlsSessionID associated for active
sessions. For further information see Section 4.4 and Section 5. sessions. For further information see Section 4.4 and Section 5.
TLS and DTLS over SCTP sessions, on the other hand, do not require a TLS and DTLS over SCTP sessions, on the other hand, do not require a
unique paring of attributes since their lower layer protocols (TCP unique pairing of attributes since their lower layer protocols (TCP
and SCTP) already provide adequate session framing. and SCTP) already provide adequate session framing.
3.2. Security Parameter Passing 3.2. Security Parameter Passing
For the (D)TLS server-side, (D)TLS-specific security parameters For the (D)TLS server-side, (D)TLS-specific security parameters
(i.e., cipher_suites, X.509 certificate fields, IP address and port) (i.e., cipher_suites, X.509 certificate fields, IP address and port)
are translated by the TLS Transport Model into security parameters are translated by the TLS Transport Model into security parameters
for the TLS Transport Model and security model (i.e., securityLevel, for the TLS Transport Model and security model (i.e., securityLevel,
securityName, transportDomain, transportAddress). The transport- securityName, transportDomain, transportAddress). The transport-
related and (D)TLS-security-related information, including the related and (D)TLS-security-related information, including the
skipping to change at page 14, line 19 skipping to change at page 14, line 8
Interface (ASI) and input from the tmStateReference cache. The Interface (ASI) and input from the tmStateReference cache. The
(D)TLS Transport Model converts that information into suitable (D)TLS Transport Model converts that information into suitable
security parameters for (D)TLS and establishes sessions as needed. security parameters for (D)TLS and establishes sessions as needed.
The elements of procedure in Section 5 discuss these concepts in much The elements of procedure in Section 5 discuss these concepts in much
greater detail. greater detail.
3.3. Notifications and Proxy 3.3. Notifications and Proxy
(D)TLS sessions may be initiated by (D)TLS clients on behalf of (D)TLS sessions may be initiated by (D)TLS clients on behalf of
command generators or notification originators. Command generators command generators, notification originators or proxy forwarders.
are frequently operated by a human, but notification originators are Command generators are frequently operated by a human, but
usually unmanned automated processes. The targets to whom notification originators and proxy forwarders are usually unmanned
notifications should be sent is typically determined and configured automated processes. The targets to whom notifications should be
by a network administrator. sent is typically determined and configured by a network
administrator.
The SNMP-TARGET-MIB module [RFC3413] contains objects for defining The SNMP-TARGET-MIB module [RFC3413] contains objects for defining
management targets, including transportDomain, transportAddress, management targets, including transportDomain, transportAddress,
securityName, securityModel, and securityLevel parameters, for securityName, securityModel, and securityLevel parameters, for
Notification Generator, Proxy Forwarder, and SNMP-controllable Notification Generator, Proxy Forwarder, and SNMP-controllable
Command Generator applications. Transport domains and transport Command Generator applications. Transport domains and transport
addresses are configured in the snmpTargetAddrTable, and the addresses are configured in the snmpTargetAddrTable, and the
securityModel, securityName, and securityLevel parameters are securityModel, securityName, and securityLevel parameters are
configured in the snmpTargetParamsTable. This document defines a MIB configured in the snmpTargetParamsTable. This document defines a MIB
module that extends the SNMP-TARGET-MIB's snmpTargetParamsTable to module that extends the SNMP-TARGET-MIB's snmpTargetParamsTable to
specify a (D)TLS client-side certificate to use for the connection. specify a (D)TLS client-side certificate to use for the connection.
When configuring a (D)TLS target, the snmpTargetAddrTDomain and When configuring a (D)TLS target, the snmpTargetAddrTDomain and
snmpTargetAddrTAddress parameters in snmpTargetAddrTable should be snmpTargetAddrTAddress parameters in snmpTargetAddrTable should be
set to the snmpTLSDomain, snmpDTLSUDPDomain, or snmpDTLSSCTPDomain set to the snmpTLSDomain, snmpDTLSUDPDomain, or snmpDTLSSCTPDomain
object and an appropriate snmpTLSAddress, snmpDTLSUDPAddress or object and an appropriate snmpTLSAddress, snmpDTLSUDPAddress or
snmpDTLSSCTPAddress value respectively. The snmpTargetParamsMPModel snmpDTLSSCTPAddress value respectively. The snmpTargetParamsMPModel
column of the snmpTargetParamsTable should be set to a value of 3 to column of the snmpTargetParamsTable should be set to a value of 3 to
indicate the SNMPv3 message processing model. The indicate the SNMPv3 message processing model. The
snmpTargetParamsSecurityName should be set to an appropriate snmpTargetParamsSecurityName should be set to an appropriate
securityName value and the tlstmParamsClientHashType and securityName value and the tlstmParamsClientFingerprint parameter of
tlstmParamsClientHashValue parameters of the tlstmParamsTable should the tlstmParamsTable should be set a value that refers to a locally
be set to values that refer to a locally held certificate to be used. held certificate to be used. The tlstmAddrServerFingerprint must be
The tlstmAddrServerHashType and tlstmAddrServerHashValue must be set set to a hash value that refers to a locally held copy of the
to a hash value that refers to a locally held copy of the server's server's presented identity certificate. Other parameters, for
presented identity certificate. Other parameters, for example example cryptographic configuration such as cipher suites to use,
cryptographic configuration such as cipher suites to use, must come must come from configuration mechanisms not defined in this document.
from configuration mechanisms not defined in this document. The The securityName defined in the snmpTargetParamsSecurityName column
other needed configuration may be configured using SNMP or other will be used by the access control model to authorize any
implementation-dependent mechanisms (for example, via a CLI). This notifications that need to be sent.
securityName defined in the snmpTargetParamsSecurityName column will
be used by the access control model to authorize any notifications
that need to be sent.
4. Elements of the Model 4. Elements of the Model
This section contains definitions required to realize the (D)TLS This section contains definitions required to realize the (D)TLS
Transport Model defined by this document. Transport Model defined by this document.
4.1. X.509 Certificates 4.1. X.509 Certificates
(D)TLS makes use of X.509 certificates for authentication of both (D)TLS makes use of X.509 certificates for authentication of both
sides of the transport. This section discusses the use of sides of the transport. This section discusses the use of
certificates in the TLSTM. An overview of X.509 certificate certificates in the TLSTM. A brief overview of X.509 certificate
infrastructure can be found in Appendix B. infrastructure can be found in Appendix B.
4.1.1. Provisioning for the Certificate 4.1.1. Provisioning for the Certificate
Authentication using (D)TLS will require that SNMP entities are Authentication using (D)TLS will require that SNMP entities are
provisioned with certificates, which are signed by trusted provisioned with certificates, which are signed by trusted
certificate authorities. Furthermore, SNMP entities will most certificate authorities. Furthermore, SNMP entities will most
commonly need to be provisioned with root certificates which commonly need to be provisioned with root certificates which
represent the list of trusted certificate authorities that an SNMP represent the list of trusted certificate authorities that an SNMP
entity can use for certificate verification. SNMP entities SHOULD entity can use for certificate verification. SNMP entities SHOULD
also be provisioned with a X.509 certificate revocation mechanism also be provisioned with a X.509 certificate revocation mechanism
which can be used to verify that a certificate has not been revoked. which can be used to verify that a certificate has not been revoked.
The certificate trust anchors, being either CA certificates or public
keys for use by self-signed certificates, must be installed through
an out of band trusted mechanism into the server and its authenticity
MUST be verified before access is granted.
The authenticated tmSecurityName of the principal is looked up using Having received a certificate, the authenticated tmSecurityName of
the tlstmCertToSNTable. This table either: the principal is looked up using the tlstmCertToSNTable. This table
either:
o Maps a certificate's fingerprint hash type and value to a directly o Maps a certificate's fingerprint type and value to a directly
specified tmSecurityName. specified tmSecurityName, or
o Identifies a certificate issuer's fingerprint hash type and value o Identifies a certificate issuer's fingerprint and allows a child
and allows child certificate's subjectAltName or CommonName to certificate's subjectAltName or CommonName to be mapped to the
directly used as the tmSecurityNome. tmSecurityNome.
The certificate trust anchors, being either CA certificates or public Implementations MAY choose to discard any connections for which no
keys for use by self-signed certificates, must be installed through potential tlstmCertToSNTable mapping exists before performing
an out of band trusted mechanism into the server and its authenticity certificate verification to avoid expending computational resources
MUST be verified before access is granted. Implementations SHOULD associated with certificate verification.
choose to discard any connections for which no potential
tlstmCertToSNTable mapping exists before performing certificate
verification to avoid expending computational resources associated
with certificate verification.
The typical enterprise configuration will map a "subjectAltName" The typical enterprise configuration will map a "subjectAltName"
component of the tbsCertificate to the TLSTM specific tmSecurityName. component of the tbsCertificate to the TLSTM specific tmSecurityName.
Thus, the authenticated identity can be obtained by the TLS Transport The authenticated identity can be obtained by the TLS Transport Model
Model by extracting the subjectAltName(s) from the peer's certificate by extracting the subjectAltName(s) from the peer's certificate. The
and the receiving application will have an appropriate tmSecurityName receiving application will then have an appropriate tmSecurityName
for use by components like an access control model. This setup for use by other SNMPv3 components like an access control model.
requires very little configuration: a single row in the
tlstmCertToSNTable referencing a certificate authority.
An example mapping setup can be found in Appendix C An example of this type of mapping setup can be found in Appendix C
This tmSecurityName may be later translated from a TLSTM specific This tmSecurityName may be later translated from a TLSTM specific
tmSecurityName to a SNMP engine securityName by the security model. tmSecurityName to a SNMP engine securityName by the security model.
A security model, like the TSM security model, may perform an A security model, like the TSM security model [RFC5591], may perform
identity mapping or a more complex mapping to derive the securityName an identity mapping or a more complex mapping to derive the
from the tmSecurityName offered by the TLS Transport Model. securityName from the tmSecurityName offered by the TLS Transport
Model.
4.2. Messages 4.2. Messages
As stated in Section 4.1.1 of [RFC4347], each DTLS record must fit As stated in Section 4.1.1 of [RFC4347], each DTLS record must fit
within a single DTLS datagram. The TLSTM SHOULD prohibit SNMP within a single DTLS datagram. The TLSTM SHOULD prohibit SNMP
messages from being sent that exceeds the maximum DTLS message size. messages from being sent that exceeds the maximum DTLS message size.
The TLSTM implementation SHOULD return an error when the DTLS message The TLSTM implementation SHOULD return an error when the DTLS message
size would be exceeded and the message won't be sent. size would be exceeded and the message won't be sent.
4.3. SNMP Services 4.3. SNMP Services
skipping to change at page 17, line 6 skipping to change at page 16, line 43
statusInformation = statusInformation =
sendMessage( sendMessage(
IN destTransportDomain -- transport domain to be used IN destTransportDomain -- transport domain to be used
IN destTransportAddress -- transport address to be used IN destTransportAddress -- transport address to be used
IN outgoingMessage -- the message to send IN outgoingMessage -- the message to send
IN outgoingMessageLength -- its length IN outgoingMessageLength -- its length
IN tmStateReference -- reference to transport state IN tmStateReference -- reference to transport state
) )
The abstract data elements passed as parameters in the abstract The abstract data elements returned from or passed as parameters into
service primitives are as follows: the abstract service primitives are as follows:
statusInformation: An indication of whether the passing of the statusInformation: An indication of whether the passing of the
message was successful. If not it is an indication of the message was successful. If not, it is an indication of the
problem. problem.
destTransportDomain: The transport domain for the associated destTransportDomain: The transport domain for the associated
destTransportAddress. The Transport Model uses this parameter to destTransportAddress. The Transport Model uses this parameter to
determine the transport type of the associated determine the transport type of the associated
destTransportAddress. This parameter may also be used by the destTransportAddress. This parameter may also be used by the
transport subsystem to route the message to the appropriate transport subsystem to route the message to the appropriate
Transport Model. This document specifies three TLS and DTLS based Transport Model. This document specifies three TLS and DTLS based
Transport Domains for use: the snmpTLSDomain, the Transport Domains for use: the snmpTLSDomain, the
snmpDTLSUDPDomain and the snmpDTLSSCTPDomain. snmpDTLSUDPDomain and the snmpDTLSSCTPDomain.
destTransportAddress: The transport address of the destination TLS destTransportAddress: The transport address of the destination TLS
Transport Model in a format specified by the SnmpTLSAddress, the Transport Model in a format specified by the SnmpTLSAddress, the
SnmpDTLSUDPAddress or the SnmpDTLSSCTPAddress TEXTUAL-CONVENTIONs. SnmpDTLSUDPAddress or the SnmpDTLSSCTPAddress TEXTUAL-CONVENTIONs.
outgoingMessage: The outgoing message to send to (D)TLS for outgoingMessage: The outgoing message to send to (D)TLS for
encapsulation. encapsulation.
outgoingMessageLength: The length of the outgoing message. outgoingMessageLength: The length of the outgoingMessage field.
tmStateReference: A handle/reference to tmSecurityData to be used tmStateReference: A handle/reference to tmSecurityData to be used
when securing outgoing messages. when securing outgoing messages.
4.3.2. SNMP Services for an Incoming Message 4.3.2. SNMP Services for an Incoming Message
The TLS Transport Model processes the received message from the The TLS Transport Model processes the received message from the
network using the (D)TLS service and then passes it to the dispatcher network using the (D)TLS service and then passes it to the dispatcher
using the following ASI: using the following ASI:
statusInformation = statusInformation =
receiveMessage( receiveMessage(
IN transportDomain -- origin transport domain IN transportDomain -- origin transport domain
IN transportAddress -- origin transport address IN transportAddress -- origin transport address
IN incomingMessage -- the message received IN incomingMessage -- the message received
IN incomingMessageLength -- its length IN incomingMessageLength -- its length
IN tmStateReference -- reference to transport state IN tmStateReference -- reference to transport state
) )
The abstract data elements passed as parameters in the abstract The abstract data elements returned from or passed as parameters into
service primitives are as follows: the abstract service primitives are as follows:
statusInformation: An indication of whether the passing of the statusInformation: An indication of whether the passing of the
message was successful. If not it is an indication of the message was successful. If not, it is an indication of the
problem. problem.
transportDomain: The transport domain for the associated transportDomain: The transport domain for the associated
transportAddress. This document specifies three TLS and DTLS transportAddress. This document specifies three TLS and DTLS
based Transport Domains for use: the snmpTLSDomain, the based Transport Domains for use: the snmpTLSDomain, the
snmpDTLSUDPDomain and the snmpDTLSSCTPDomain. snmpDTLSUDPDomain and the snmpDTLSSCTPDomain.
transportAddress: The transport address of the source of the transportAddress: The transport address of the source of the
received message in a format specified by the SnmpTLSAddress, the received message in a format specified by the SnmpTLSAddress, the
SnmpDTLSUDPAddress or the SnmpDTLSSCTPAddress TEXTUAL-CONVENTION. SnmpDTLSUDPAddress or the SnmpDTLSSCTPAddress TEXTUAL-CONVENTION.
incomingMessage: The whole SNMP message stripped of all (D)TLS incomingMessage: The whole SNMP message after being processed by
protection data. (D)TLS and removed of the (D)TLS transport layer data.
incomingMessageLength: The length of the SNMP message after being incomingMessageLength: The length of the incomingMessage field.
processed by (D)TLS.
tmStateReference: A handle/reference to tmSecurityData to be used by tmStateReference: A handle/reference to tmSecurityData to be used by
the security model. the security model.
4.4. (D)TLS Services 4.4. (D)TLS Services
This section describes the services provided by the (D)TLS Transport This section describes the services provided by the (D)TLS Transport
Model with their inputs and outputs. These services are between the Model with their inputs and outputs. These services are between the
TLS Transport Model and the (D)TLS transport layer. The following TLS Transport Model and the (D)TLS transport layer. The following
sections describe services for establishing and closing a session and sections describe services for establishing and closing a session and
skipping to change at page 18, line 51 skipping to change at page 18, line 41
statusInformation = -- errorIndication or success statusInformation = -- errorIndication or success
openSession( openSession(
IN destTransportDomain -- transport domain to be used IN destTransportDomain -- transport domain to be used
IN destTransportAddress -- transport address to be used IN destTransportAddress -- transport address to be used
IN securityName -- on behalf of this principal IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security requested IN securityLevel -- Level of Security requested
OUT tlsSessionID -- Session identifier for (D)TLS OUT tlsSessionID -- Session identifier for (D)TLS
) )
The abstract data elements passed as parameters in the abstract The abstract data elements returned from or passed as parameters into
service primitives are as follows: the abstract service primitives are as follows:
statusInformation: An indication of whether the process was statusInformation: An indication of whether the process was
successful or not. If not, then the status information will successful or not. If not, then the status information will
include the error indication provided by (D)TLS. include the error indication provided by (D)TLS.
destTransportDomain: The transport domain for the associated destTransportDomain: The transport domain for the associated
destTransportAddress. The TLS Transport Model uses this parameter destTransportAddress. The TLS Transport Model uses this parameter
to determine the transport type of the associated to determine the transport type of the associated
destTransportAddress. This document specifies three TLS and DTLS destTransportAddress. This document specifies three TLS and DTLS
based Transport Domains for use: the snmpTLSDomain, the based Transport Domains for use: the snmpTLSDomain, the
skipping to change at page 19, line 26 skipping to change at page 19, line 16
destTransportAddress: The transport address of the destination TLS destTransportAddress: The transport address of the destination TLS
Transport Model in a format specified by the SnmpTLSAddress, the Transport Model in a format specified by the SnmpTLSAddress, the
SnmpDTLSUDPAddress or the SnmpDTLSSCTPAddress TEXTUAL-CONVENTION. SnmpDTLSUDPAddress or the SnmpDTLSSCTPAddress TEXTUAL-CONVENTION.
securityName: The security name representing the principal on whose securityName: The security name representing the principal on whose
behalf the message will be sent. behalf the message will be sent.
securityLevel: The level of security requested by the application. securityLevel: The level of security requested by the application.
dtlsSessionID: An implementation-dependent session identifier to tlsSessionID: An implementation-dependent session identifier to
reference the specific (D)TLS session. reference the specific (D)TLS session.
DTLS and UDP do not provide a session de-multiplexing mechanism and Neither DTLS or UDP provides a session de-multiplexing mechanism and
it is possible that implementations will only be able to identify a it is possible that implementations will only be able to identify a
unique session based on a unique combination of source address, unique session based on a unique combination of source address,
destination address, source UDP port number and destination UDP port destination address, source UDP port number and destination UDP port
number. Because of this, when establishing a new sessions number. Because of this, when establishing a new sessions
implementations MUST use a different UDP source port number for each implementations MUST use a different UDP source port number for each
connection to a remote destination IP-address/port-number combination connection to a given remote destination IP-address/port-number
to ensure the remote entity can properly disambiguate between combination to ensure the remote entity can properly disambiguate
multiple sessions from a host to the same port on a server. TLS and between multiple sessions from a host to the same port on a server.
DTLS over SCTP provide session de-multiplexing so this restriction is TLS and DTLS over SCTP provide session de-multiplexing so this
not needed for TLS or DTLS over SCTP implementations. restriction is not needed for TLS or DTLS over SCTP implementations.
The procedural details for establishing a session are further The procedural details for establishing a session are further
described in Section 5.3. described in Section 5.3.
Upon completion of the process the TLS Transport Model returns status Upon completion of the process the TLS Transport Model returns status
information and, if the process was successful the dtlsSessionID. information and, if the process was successful the tlsSessionID for
Other implementation-dependent data from (D)TLS are also returned. the session. Other implementation-dependent data from (D)TLS may
The dtlsSessionID is stored in an implementation- dependent manner also be returned. The tlsSessionID is formatted and stored in an
and tied to the tmSecurityData for future use of this session. implementation-dependent manner. It is tied to the tmSecurityData
for future use of this session and must remain constant and unique
while the session is open.
4.4.2. (D)TLS Services for an Incoming Message 4.4.2. (D)TLS Services for an Incoming Message
When the TLS Transport Model invokes the (D)TLS record layer to When the TLS Transport Model invokes the (D)TLS record layer to
verify proper security for the incoming message, it must use the verify proper security for the incoming message, it must use the
following ASI: following ASI:
statusInformation = -- errorIndication or success statusInformation = -- errorIndication or success
tlsRead( tlsRead(
IN tlsSessionID -- Session identifier for (D)TLS IN tlsSessionID -- Session identifier for (D)TLS
IN wholeTlsMsg -- as received on the wire IN wholeTlsMsg -- as received on the wire
IN wholeTlsMsgLength -- length as received on the wire IN wholeTlsMsgLength -- length as received on the wire
OUT incomingMessage -- the whole SNMP message from (D)TLS OUT incomingMessage -- the whole SNMP message from (D)TLS
OUT incomingMessageLength -- the length of the SNMP message OUT incomingMessageLength -- the length of the SNMP message
) )
The abstract data elements passed as parameters in the abstract The abstract data elements returned from or passed as parameters into
service primitives are as follows: the abstract service primitives are as follows:
statusInformation: An indication of whether the process was statusInformation: An indication of whether the process was
successful or not. If not, then the status information will successful or not. If not, then the status information will
include the error indication provided by (D)TLS. include the error indication provided by (D)TLS.
tlsSessionID: An implementation-dependent session identifier to tlsSessionID: An implementation-dependent session identifier to
reference the specific (D)TLS session. How the (D)TLS session ID reference the specific (D)TLS session. How the (D)TLS session ID
is obtained for each message is implementation-dependent. As an is obtained for each message is implementation-dependent. As an
implementation hint, for dtls over udp the TLS Transport Model can implementation hint for DTLS over UDP, the TLS Transport Model
examine incoming messages to determine the source IP address, might examine incoming messages to determine the source IP
source port number, destination IP address, and destination port address, source port number, destination IP address, and
number and use these values to look up the local tlsSessionID in destination port number and use these values to look up the local
the list of active sessions. tlsSessionID in the list of active sessions.
wholeDtlsMsg: The whole message as received on the wire. wholeDtlsMsg: The whole message as received on the wire.
wholeDtlsMsgLength: The length of the message as it was received on wholeDtlsMsgLength: The length of the wholeDtlsMsg field.
the wire.
incomingMessage: The whole SNMP message stripped of all (D)TLS incomingMessage: The whole SNMP message after being processed by
privacy and integrity data. (D)TLS and removed of the (D)TLS transport layer data.
incomingMessageLength: The length of the SNMP message stripped of incomingMessageLength: The length of the incomingMessage field.
all (D)TLS privacy and integrity data.
4.4.3. (D)TLS Services for an Outgoing Message 4.4.3. (D)TLS Services for an Outgoing Message
When the TLS Transport Model invokes the (D)TLS record layer to When the TLS Transport Model invokes the (D)TLS record layer to
encapsulate and transmit a SNMP message, it must use the following encapsulate and transmit a SNMP message, it must use the following
ASI. ASI.
statusInformation = -- errorIndication or success statusInformation = -- errorIndication or success
tlsWrite( tlsWrite(
IN tlsSessionID -- Session identifier for (D)TLS IN tlsSessionID -- Session identifier for (D)TLS
IN outgoingMessage -- the message to send IN outgoingMessage -- the message to send
IN outgoingMessageLength -- its length IN outgoingMessageLength -- its length
) )
The abstract data elements returned from or passed as parameters into
The abstract data elements passed as parameters in the abstract the abstract service primitives are as follows:
service primitives are as follows:
statusInformation: An indication of whether the process was statusInformation: An indication of whether the process was
successful or not. If not, then the status information will successful or not. If not, then the status information will
include the error indication provided by (D)TLS. include the error indication provided by (D)TLS.
tlsSessionID: An implementation-dependent session identifier to tlsSessionID: An implementation-dependent session identifier to
reference the specific (D)TLS session that the message should be reference the specific (D)TLS session that the message should be
sent using. sent using.
outgoingMessage: The outgoing message to send to (D)TLS for outgoingMessage: The outgoing message to send to (D)TLS for
encapsulation. encapsulation.
outgoingMessageLength: The length of the outgoing message. outgoingMessageLength: The length of the outgoingMessage field.
4.5. Cached Information and References 4.5. Cached Information and References
When performing SNMP processing, there are two levels of state When performing SNMP processing, there are two levels of state
information that may need to be retained: the immediate state linking information that may need to be retained: the immediate state linking
a request-response pair, and potentially longer-term state relating a request-response pair, and potentially longer-term state relating
to transport and security. "Transport Subsystem for the Simple to transport and security. "Transport Subsystem for the Simple
Network Management Protocol" [I-D.ietf-isms-tmsm] defines general Network Management Protocol" [RFC5590] defines general requirements
requirements for caches and references. for caches and references.
4.5.1. TLS Transport Model Cached Information 4.5.1. TLS Transport Model Cached Information
The TLSTM has no specific responsibilities regarding the cached The TLSTM has no specific responsibilities regarding the cached
information beyond those discussed in "Transport Subsystem for the information beyond those discussed in "Transport Subsystem for the
Simple Network Management Protocol" [I-D.ietf-isms-tmsm] Simple Network Management Protocol" [RFC5590]
5. Elements of Procedure 5. Elements of Procedure
Abstract service interfaces have been defined by RFC 3411 to describe Abstract service interfaces have been defined by [RFC3411] and
the conceptual data flows between the various subsystems within an further augmented by [RFC5590] to describe the conceptual data flows
SNMP entity. The TLSTM uses some of these conceptual data flows when between the various subsystems within an SNMP entity. The TLSTM uses
communicating between subsystems. These RFC 3411-defined data flows some of these conceptual data flows when communicating between
are referred to here as public interfaces. subsystems.
To simplify the elements of procedure, the release of state To simplify the elements of procedure, the release of state
information is not always explicitly specified. As a general rule, information is not always explicitly specified. As a general rule,
if state information is available when a message gets discarded, the if state information is available when a message gets discarded, the
message-state information should also be released. If state message-state information should also be released. If state
information is available when a session is closed, the session state information is available when a session is closed, the session state
information should also be released. Sensitive information, like information should also be released. Sensitive information, like
cryptographic keys, should be overwritten appropriately first prior cryptographic keys, should be overwritten appropriately first prior
to being released. to being released.
An error indication may return an OID and value for an incremented An error indication in statusInformation will typically include the
counter if the information is available at the point where the error Object Identifier (OID) and value for an incremented error counter.
is detected. This may be accompanied by the requested securityLevel and the
tmStateReference. Per-message context information is not accessible
to Transport Models, so for the returned counter OID and value,
contextEngine would be set to the local value of snmpEngineID and
contextName to the default context for error counters.
5.1. Procedures for an Incoming Message 5.1. Procedures for an Incoming Message
This section describes the procedures followed by the (D)TLS This section describes the procedures followed by the (D)TLS
Transport Model when it receives a (D)TLS protected packet. The Transport Model when it receives a (D)TLS protected packet. The
steps are broken into two different sections. Section 5.1.1 steps are broken into two different sections. Section 5.1.1
describes the needed steps for de-multiplexing multiple DTLS describes the needed steps for de-multiplexing multiple DTLS
sessions, which is specifically needed for DTLS over UDP sessions. sessions, which is specifically needed for DTLS over UDP sessions.
Section 5.1.2 describes the steps specific to transport processing Section 5.1.2 describes the steps specific to transport processing
once the (D)TLS processing has been completed. once the (D)TLS processing has been completed. It is assumed that
TLS and DTLS/SCP protocol implementations already provide appropriate
message demultiplexing and only the processing steps in Section 5.1.2
are needed.
5.1.1. DTLS Processing for Incoming Messages 5.1.1. DTLS Processing for Incoming Messages
DTLS is significantly different in terms of session handling than DTLS is significantly different in terms of session handling than
TCP-based session streams like SSH or TLS. The DTLS protocol, which when TLS or DTLS is run over session based streaming protocols like
is datagram-based, does not have a session identifier when run over TCP or SCTP. Specifically, the DTLS protocol, when run over UDP,
UDP that allows implementations to determine through what session a does not have a session identifier that allows implementations to
packet arrived. DTLS over SCTP and TLS over TCP streams have built determine through what session a packet arrived. DTLS over SCTP and
in session demultiplexing and thus the steps in this section are not TLS over TCP streams have built in session demultiplexing and thus
necessary for those protocol combinations. It is always critical, the steps in this section are not necessary for those protocol
however, that implementations be able to derive a tlsSessionID from combinations. It is always critical, however, that implementations
any demultiplexing process. be able to derive a tlsSessionID from any session demultiplexing
process.
A process for de-multiplexing multiple DTLS sessions arriving over A process for demultiplexing multiple DTLS sessions arriving over UDP
UDP must be incorporated into the procedures for processing an must be incorporated into the procedures for processing an incoming
incoming message. The steps in this section describe how this can be message. The steps in this section describe one possible method to
accomplished, although any implementation dependent method should be accomplish this, although any implementation dependent method should
suitable as long as the results are consistently deterministic. The be suitable as long as the results are consistently deterministic.
important output results from the steps in this process are the The important output results from the steps in this process are the
transportDomain, the transportAddress, the wholeMessage, the transportDomain, the transportAddress, the wholeMessage, the
wholeMessageLength, and a unique implementation-dependent session wholeMessageLength, and a unique implementation-dependent session
identifier (tlsSessionID). identifier (tlsSessionID).
This demultiplexing procedure assumes that upon session establishment This demultiplexing procedure assumes that upon session establishment
an entry in a local transport mapping table is created in the an entry in a local transport mapping table is created in the
Transport Model's Local Configuration Datastore (LCD). The transport Transport Model's Local Configuration Datastore (LCD). The transport
mapping table's entry should map a unique combination of the remote mapping table's entry should map a unique combination of the remote
address, remote port number, local address and local port number to a address, remote port number, local address and local port number to
implementation-dependent tlsSessionID. an implementation-dependent tlsSessionID.
1) The TLS Transport Model examines the raw UDP message, in an 1) The TLS Transport Model examines the raw UDP message, in an
implementation-dependent manner. If the message is not a DTLS implementation-dependent manner. If the message is not a DTLS
message then it should be discarded. If the message is not a message then it should be discarded. If the message is not a
(D)TLS Application Data message then the message should be (D)TLS Application Data message (such as a session initialization
processed by the underlying DTLS framework as it is (for example) or session modification message) then the message should be
a session initialization or session modification message and no processed by the underlying DTLS framework and no further steps
further steps below should be taken by the DTLS Transport. below should be taken by the DTLS Transport.
2) The TLS Transport Model queries the LCD using the transport 2) The TLS Transport Model queries the LCD using the transport
parameters (source and destination addresses and ports) to parameters (source and destination addresses and ports) to
determine if a session already exists and its tlsSessionID. determine if a session already exists and its tlsSessionID.
3) If a matching entry in the LCD does not exist then the message is 3) If a matching entry in the LCD does not exist then the message is
discarded. Increment the tlstmSessionNoAvailableSessions counter discarded. Increment the tlstmSessionNoAvailableSessions counter
and stop processing the message. and stop processing the message.
Note that an entry would already exist if the client and server's Note that an entry would already exist if the client and server's
skipping to change at page 23, line 37 skipping to change at page 23, line 37
entry may not exist, however, if a "rogue" message was routed to entry may not exist, however, if a "rogue" message was routed to
the SNMP entity by mistake. An entry might also be missing the SNMP entity by mistake. An entry might also be missing
because of a "broken" session (see operational considerations). because of a "broken" session (see operational considerations).
4) Retrieve the tlsSessionID from the LCD. 4) Retrieve the tlsSessionID from the LCD.
5) The tlsWholeMsg, and the tlsSessionID are passed to DTLS for 5) The tlsWholeMsg, and the tlsSessionID are passed to DTLS for
integrity checking and decryption using the tlsRead() ASI. integrity checking and decryption using the tlsRead() ASI.
6) If the message fails integrity checks or other (D)TLS security 6) If the message fails integrity checks or other (D)TLS security
processing then the tlstmDTLSProtectionErrors counter is processing then increment the tlstmDTLSProtectionErrors counter,
incremented, the message is discarded and processing of the discard and stop processing the message.
message is stopped.
7) The output of the tlsRead results in an incomingMessage and an 7) The output of the tlsRead ASI results in an incomingMessage and
incomingMessageLength. These results and the tlsSessionID are an incomingMessageLength. These results and the tlsSessionID are
used below in the Section 5.1.2 to complete the processing of the used below in the Section 5.1.2 to complete the processing of the
incoming message. incoming message.
5.1.2. Transport Processing for Incoming Messages 5.1.2. Transport Processing for Incoming Messages
The procedures in this section describe how the TLS Transport Model The procedures in this section describe how the TLS Transport Model
should process messages that have already been properly extracted should process messages that have already been properly extracted
from the (D)TLS stream. from the (D)TLS stream.
Create a tmStateReference cache for the subsequent reference and Create a tmStateReference cache for the subsequent reference and
skipping to change at page 24, line 18 skipping to change at page 24, line 16
tmTransportDomain = snmpTLSDomain, snmpDTLSUDPDomain or tmTransportDomain = snmpTLSDomain, snmpDTLSUDPDomain or
snmpDTLSSCTPDomain as appropriate. snmpDTLSSCTPDomain as appropriate.
tmTransportAddress = The address the message originated from, tmTransportAddress = The address the message originated from,
determined in an implementation dependent way. determined in an implementation dependent way.
tmSecurityLevel = The derived tmSecurityLevel for the session, as tmSecurityLevel = The derived tmSecurityLevel for the session, as
discussed in Section 3.1.2 and Section 5.3. discussed in Section 3.1.2 and Section 5.3.
tmSecurityName = The derived tmSecurityName for the session as tmSecurityName = The derived tmSecurityName for the session as
discussed in and Section 5.3. This value MUST be constant during discussed in Section 5.3. This value MUST be constant during the
the lifetime of the (D)TLS session. lifetime of the (D)TLS session.
tmSessionID = The tlsSessionID, which MUST be a unique session tmSessionID = The tlsSessionID, which MUST be a unique session
identifier for this (D)TLS session. The contents and format of identifier for this (D)TLS session. The contents and format of
this identifier are implementation dependent as long as it is this identifier are implementation dependent as long as it is
unique to the session. A session identifier MUST NOT be reused unique to the session. A session identifier MUST NOT be reused
until all references to it are no longer in use. The tmSessionID until all references to it are no longer in use. The tmSessionID
is equal to the tlsSessionID discussed in Section 5.1.1. is equal to the tlsSessionID discussed in Section 5.1.1.
tmSessionID refers to the session identifier when stored in the tmSessionID refers to the session identifier when stored in the
tmStateReference and tlsSessionID refers to the session identifier tmStateReference and tlsSessionID refers to the session identifier
when stored in the LCD. They MUST always be equal when processing when stored in the LCD. They MUST always be equal when processing
skipping to change at page 24, line 47 skipping to change at page 24, line 45
wholeMessage, and wholeMessageLength to the dispatcher using the wholeMessage, and wholeMessageLength to the dispatcher using the
receiveMessage ASI: receiveMessage ASI:
statusInformation = statusInformation =
receiveMessage( receiveMessage(
IN transportDomain -- snmpTLSDomain, snmpDTLSUDPDomain, IN transportDomain -- snmpTLSDomain, snmpDTLSUDPDomain,
-- or snmpDTLSSCTPDomain -- or snmpDTLSSCTPDomain
IN transportAddress -- address for the received message IN transportAddress -- address for the received message
IN wholeMessage -- the whole SNMP message from (D)TLS IN wholeMessage -- the whole SNMP message from (D)TLS
IN wholeMessageLength -- the length of the SNMP message IN wholeMessageLength -- the length of the SNMP message
IN tmStateReference -- (NEW) transport info IN tmStateReference -- transport info
) )
5.2. Procedures for an Outgoing Message 5.2. Procedures for an Outgoing Message
The dispatcher sends a message to the TLS Transport Model using the The dispatcher sends a message to the TLS Transport Model using the
following ASI: following ASI:
statusInformation = statusInformation =
sendMessage( sendMessage(
IN destTransportDomain -- transport domain to be used IN destTransportDomain -- transport domain to be used
IN destTransportAddress -- transport address to be used IN destTransportAddress -- transport address to be used
IN outgoingMessage -- the message to send IN outgoingMessage -- the message to send
IN outgoingMessageLength -- its length IN outgoingMessageLength -- its length
IN tmStateReference -- (NEW) transport info IN tmStateReference -- transport info
) )
This section describes the procedure followed by the TLS Transport This section describes the procedure followed by the TLS Transport
Model whenever it is requested through this ASI to send a message. Model whenever it is requested through this ASI to send a message.
1) Extract tmSessionID, tmTransportAddress, tmSecurityName, 1) Extract the tmSessionID, tmTransportAddress, tmSecurityName,
tmRequestedSecurityLevel. and tmSameSecurity from the tmRequestedSecurityLevel, and tmSameSecurity values from the
tmStateReference. Note: The tmSessionID value may be undefined tmStateReference. Note: The tmSessionID value may be undefined
if session exists yet. if no session exists yet over which the message can be sent.
2) If tmSameSecurity is true and either tmSessionID is undefined or 2) If tmSameSecurity is true and either tmSessionID is undefined or
refers to a session that is no longer open then increment the refers to a session that is no longer open then increment the
tlstmSessionNoAvailableSessions counter, discard the message and tlstmSessionNoAvailableSessions counter, discard the message and
return the error indication in the statusInformation. Processing return the error indication in the statusInformation. Processing
of this message stops. of this message stops.
3) If tmSameSecurity is false and tmSessionID refers to a session 3) If tmSameSecurity is false and tmSessionID refers to a session
that is no longer available then an implementation SHOULD open a that is no longer available then an implementation SHOULD open a
new session using the openSession() ASI as described below in new session using the openSession() ASI (described in greater
step 4b. An implementation MAY choose to return an error to the detail in step 4b). An implementation MAY choose to return an
calling module. error to the calling module and stop processing of the message.
4) If tmSessionID is undefined, then use tmTransportAddress, 4) If tmSessionID is undefined, then use tmTransportAddress,
tmSecurityName and tmRequestedSecurityLevel to see if there is a tmSecurityName and tmRequestedSecurityLevel to see if there is a
corresponding entry in the LCD suitable to send the message over. corresponding entry in the LCD suitable to send the message over.
4a) If there is a corresponding LCD entry, then this session 4a) If there is a corresponding LCD entry, then this session
will be used to send the message. will be used to send the message.
4b) If there is not a corresponding LCD entry, then open a 4b) If there is not a corresponding LCD entry, then open a
session using the openSession() ASI (discussed further in session using the openSession() ASI (discussed further in
Section 4.4.1). Implementations MAY wish to offer message Section 4.4.1). Implementations MAY wish to offer message
buffering to prevent redundant openSession() calls for the buffering to prevent redundant openSession() calls for the
same cache entry. If an error is returned from same cache entry. If an error is returned from
OpenSession(), then discard the message, increment the OpenSession(), then discard the message, increment the
tlstmSessionOpenErrors, and return an error indication to tlstmSessionOpenErrors, return an error indication to the
the calling module. calling module and stop processing of the message.
5) Using either the session indicated by the tmSessionID if there 5) Using either the session indicated by the tmSessionID if there
was one or the session resulting in the previous step, pass the was one or the session resulting from a previous step (3 or 4),
outgoingMessage to (D)TLS for encapsulation and transmission. pass the outgoingMessage to (D)TLS for encapsulation and
transmission.
5.3. Establishing a Session 5.3. Establishing a Session
The TLS Transport Model provides the following primitive to establish The TLS Transport Model provides the following primitive to establish
a new (D)TLS session (previously discussed in Section 4.4.1): a new (D)TLS session (previously discussed in Section 4.4.1):
statusInformation = -- errorIndication or success statusInformation = -- errorIndication or success
openSession( openSession(
IN destTransportDomain -- transport domain to be used IN destTransportDomain -- transport domain to be used
IN destTransportAddress -- transport address to be used IN destTransportAddress -- transport address to be used
IN securityName -- on behalf of this principal IN securityName -- on behalf of this principal
IN securityLevel -- Level of Security requested IN securityLevel -- Level of Security requested
OUT tlsSessionID -- Session identifier for (D)TLS OUT tlsSessionID -- Session identifier for (D)TLS
) )
The following describes the procedure to follow to establish a SNMP The following describes the procedure to follow when establishing a
over (D)TLS session between SNMP engines to exchange SNMP messages. SNMP over (D)TLS session between SNMP engines for exchanging SNMP
This process is followed by any SNMP engine establishing a session messages. This process is followed by any SNMP engine establishing a
for subsequent use. session for subsequent use.
This MAY be done automatically for SNMP messages which are not This MAY be done automatically for SNMP messages which are not
Response or Report messages. Response or Report messages.
(D)TLS provides no explicit manner for transmitting an identity the
client wishes to connect to during or prior to key exchange to
facilitate certificate selection at the server (e.g. at a
Notification Receiver). I.E., there is no available mechanism for
sending notifications to a specific principal at a given TCP, UDP or
SCTP port. Therefore, implementations MAY support responding with
multiple identities using separate TCP, UDP or SCTP port numbers to
indicate the desired principal or some other implementation-dependent
solution.
1) The client selects the appropriate certificate and cipher_suites 1) The client selects the appropriate certificate and cipher_suites
for the key agreement based on the tmSecurityName and the for the key agreement based on the tmSecurityName and the
tmRequestedSecurityLevel for the session. For sessions being tmRequestedSecurityLevel for the session. For sessions being
established as a result of a SNMP-TARGET-MIB based operation, the established as a result of a SNMP-TARGET-MIB based operation, the
certificate will potentially have been identified via the certificate will potentially have been identified via the
tlstmParamsTable mapping and the cipher_suites will have to be tlstmParamsTable mapping and the cipher_suites will have to be
taken from system-wide or implementation-specific configuration. taken from system-wide or implementation-specific configuration.
Otherwise, the certificate and appropriate cipher_suites will Otherwise, the certificate and appropriate cipher_suites will
need to be passed to the openSession() ASI as supplemental need to be passed to the openSession() ASI as supplemental
information or configured through an implementation-dependent information or configured through an implementation-dependent
mechanism. It is also implementation-dependent and possibly mechanism. It is also implementation-dependent and possibly
policy-dependent how tmRequestedSecurityLevel will be used to policy-dependent how tmRequestedSecurityLevel will be used to
influence the security capabilities provided by the (D)TLS influence the security capabilities provided by the (D)TLS
session. However this is done, the security capabilities session. However this is done, the security capabilities
provided by (D)TLS MUST be at least as high as the level of provided by (D)TLS MUST be at least as high as the level of
security indicated by the tmRequestedSecurityLevel parameter. security indicated by the tmRequestedSecurityLevel parameter.
The actual security level of the session should be reported in The actual security level of the session is reported in the
the tmStateReference cache as tmSecurityLevel. For (D)TLS to tmStateReference cache as tmSecurityLevel. For (D)TLS to provide
provide strong authentication, each principal acting as a Command strong authentication, each principal acting as a Command
Generator SHOULD have its own certificate. Generator SHOULD have its own certificate.
2) Using the destTransportDomain and destTransportAddress values, 2) Using the destTransportDomain and destTransportAddress values,
the client will initiate the (D)TLS handshake protocol to the client will initiate the (D)TLS handshake protocol to
establish session keys for message integrity and encryption. establish session keys for message integrity and encryption.
If the attempt to establish a session is unsuccessful, then If the attempt to establish a session is unsuccessful, then
tlstmSessionOpenErrors is incremented, an error indication is tlstmSessionOpenErrors is incremented, an error indication is
returned, and session establishment processing stops. returned, and processing stops.
3) Once the secure session is established and both sides have been 3) Once a (D)TLS secured session is established and both sides have
authenticated, certificate validation and identity expectations performed any appropriate certificate authentication verification
are performed. (e.g. [RFC5280]) then each side will determine and/or check the
identity of the remote entity using the procedures described
below.
a) The (D)TLS server side of the connection identifies the a) The (D)TLS server side of the connection identifies the
authenticated identity from the (D)TLS client's principal authenticated identity from the (D)TLS client's principal
certificate using appropriate certificate path validation certificate using configuration information from the
procedures (e.g. [RFC5280]) using configuration information tlstmCertToSNTable mapping table. The resulting derived
from the tlstmCertToSNTable mapping table. The resulting securityName is recorded in the tmStateReference cache as
derived securityName is recorded in the tmStateReference tmSecurityName. The details of the lookup process are fully
cache as tmSecurityName. The details of the lookup process described in the DESCRIPTION clause of the tlstmCertToSNTable
are fully described in the DESCRIPTION clause of the MIB object. If any verification fails in any way (for
tlstmCertToSNTable MIB object. If this verification fails in example because of failures in cryptographic verification or
any way (for example because of failures in cryptographic because of the lack of an appropriate row in the
verification or the lack of an appropriate row in the
tlstmCertToSNTable) then the session establishment MUST fail, tlstmCertToSNTable) then the session establishment MUST fail,
the tlstmSessionInvalidClientCertificates object is the tlstmSessionInvalidClientCertificates object is
incremented and processing is stopped. incremented and processing stops.
b) The (D)TLS client side of the connection SHOULD verify that b) The (D)TLS client side of the connection MUST verify that
authenticated identity of the (D)TLS server's certificate is authenticated identity of the (D)TLS server's certificate is
the certificate expected. This can be done using the the certificate expected. This can be done using the
configuration found in the tlstmAddrTable if the client is configuration fingerprints found in the tlstmAddrTable if the
establishing the connection based on SNMP-TARGET-MIB client is establishing the connection based on SNMP-TARGET-
configuration. The client MUST always perform appropriate MIB configuration or based on external certificate path
certificate path validation procedures (e.g. [RFC5280]) to validation processes (e.g. [RFC5280]).
ensure the certificate is cryptographically valid.
If strong authentication is desired then the (D)TLS server Methods for verifying that the proper destination was reached
address or naming mechanism MUST always be verified against based on the presented certificate are described in
the certificate's contents. Methods for doing this are [I-D.saintandre-tls-server-id-check]. Matching the server's
described in [I-D.saintandre-tls-server-id-check]. Matching naming against SubjectAltName extension values SHOULD be the
the server's naming against SubjectAltName extension values preferred mechanism for comparison, but matching the
is the preferred mechanism for comparison, but matching the
CommonName MAY be used. CommonName MAY be used.
(D)TLS provides assurance that the authenticated identity has (D)TLS provides assurance that the authenticated identity has
been signed by a trusted configured certificate authority. been signed by a trusted configured certificate authority.
If verification of the server's certificate fails in any way If verification of the server's certificate fails in any way
(for example because of failures in cryptographic (for example because of failures in cryptographic
verification or the presented identity was not the expected verification or the presented identity was not the expected
identity) then the session establishment MUST fail, the identity) then the session establishment MUST fail, the
tlstmSessionInvalidServerCertificates object is incremented tlstmSessionInvalidServerCertificates object is incremented
and processing is stopped. and processing stops.
4) The (D)TLS-specific session identifier is passed to the TLS 4) The (D)TLS-specific session identifier is passed to the TLS
Transport Model and associated with the tmStateReference cache Transport Model and associated with the tmStateReference cache
entry to indicate that the session has been established entry to indicate that the session has been established
successfully and to point to a specific (D)TLS session for future successfully and to point to a specific (D)TLS session for future
use. use.
(D)TLS provides no explicit manner for transmitting an identity the
client wishes to connect to during or prior to key exchange to
facilitate certificate selection at the server (e.g. at a
Notification Receiver). I.E., there is no available mechanism for
sending notifications to a specific principal at a given TCP, UDP or
SCTP port. Therefore, an implementation that wishes to support
multiple identities MAY use separate TCP, UDP or SCTP port numbers to
indicate the desired principal or some other implementation-dependent
solution.
5.4. Closing a Session 5.4. Closing a Session
The TLS Transport Model provides the following primitive to close a The TLS Transport Model provides the following primitive to close a
session: session:
statusInformation = statusInformation =
closeSession( closeSession(
IN tmStateReference -- transport info IN tmStateReference -- transport info
) )
The following describes the procedure to follow to close a session The following describes the procedure to follow to close a session
between a client and server. This process is followed by any SNMP between a client and server. This process is followed by any SNMP
engine closing the corresponding SNMP session. engine closing the corresponding SNMP session.
1) Look up the session in the cache and the LCD using the 1) Look up the session in the cache and the LCD using the
tmStateReference. tmStateReference and its contents.
2) If there is no session open associated with the tmStateReference, 2) If there is no session open associated with the tmStateReference,
then closeSession processing is completed. then closeSession processing is completed.
3) Delete the entry from the cache and any other implementation- 3) Delete the entry from the cache and any other implementation-
dependent information in the LCD. dependent information in the LCD.
4) Have (D)TLS close the specified session. This SHOULD include 4) Have (D)TLS close the specified session. This SHOULD include
sending a close_notify TLS Alert to inform the other side that sending a close_notify TLS Alert to inform the other side that
session cleanup may be performed. session cleanup may be performed.
6. MIB Module Overview 6. MIB Module Overview
This MIB module provides management of the TLS Transport Model. It This MIB module provides management of the TLS Transport Model. It
defines needed textual conventions, statistical counters and defines needed textual conventions, statistical counters,
configuration infrastructure necessary for session establishment. notifications and configuration infrastructure necessary for session
Example usage of the configuration tables can be found in Appendix C. establishment. Example usage of the configuration tables can be
found in Appendix C.
6.1. Structure of the MIB Module 6.1. Structure of the MIB Module
Objects in this MIB module are arranged into subtrees. Each subtree Objects in this MIB module are arranged into subtrees. Each subtree
is organized as a set of related objects. The overall structure and is organized as a set of related objects. The overall structure and
assignment of objects to their subtrees, and the intended purpose of assignment of objects to their subtrees, and the intended purpose of
each subtree, is shown below. each subtree, is shown below.
6.2. Textual Conventions 6.2. Textual Conventions
Generic and Common Textual Conventions used in this module can be Generic and Common Textual Conventions used in this module can be
found summarized at http://www.ops.ietf.org/mib-common-tcs.html found summarized at http://www.ops.ietf.org/mib-common-tcs.html
This module defines the following new Textual Conventions: This module defines the following new Textual Conventions:
o A new TransportDomain and TransportAddress format for describing o New TransportDomain and TransportAddress formats for describing
(D)TLS connection addressing requirements. (D)TLS connection addressing requirements.
o Public certificate fingerprint Hashing Types and Values. These o Public certificate fingerprint allowing MIB module objects to
textual conventions allow for MIB module objects to refer generically refer to a stored X.509 certificate using a
generically to a stored X.509 certificate using a simple hash cryptographic hash as a reference pointer.
value as a reference pointer.
6.3. Statistical Counters 6.3. Statistical Counters
The TLSTM-MIB defines some statical counters that can provide network The TLSTM-MIB defines some statical counters that can provide network
managers with feedback about (D)TLS session usage and potential managers with feedback about (D)TLS session usage and potential
errors that a MIB-instrumented device may be experiencing. errors that a MIB-instrumented device may be experiencing.
6.4. Configuration Tables 6.4. Configuration Tables
The TLSTM-MIB defines configuration tables that a manager can use for The TLSTM-MIB defines configuration tables that a manager can use for
help in configuring a MIB-instrumented device for sending and configuring a MIB-instrumented device for sending and receiving SNMP
receiving SNMP messages over (D)TLS. In particular, there is a MIB messages over (D)TLS. In particular, there is are MIB tables that
table that extends the SNMP-TARGET-MIB for configuring certificates extend the SNMP-TARGET-MIB for configuring (D)TLS certificate usage
to be used and a MIB table for mapping incoming (D)TLS client and a MIB table for mapping incoming (D)TLS client certificates to
certificates to securityNames. SNMPv3 securityNames.
6.4.1. Notifications
The TLSTM-MIB defines notifications to alert management stations when
a (D)TLS connection fails because the server's presented certificate
did not meet an expected value, according to the tlstmAddrTable.
6.5. Relationship to Other MIB Modules 6.5. Relationship to Other MIB Modules
Some management objects defined in other MIB modules are applicable Some management objects defined in other MIB modules are applicable
to an entity implementing the TLS Transport Model. In particular, it to an entity implementing the TLS Transport Model. In particular, it
is assumed that an entity implementing the TLSTM-MIB will implement is likely that an entity implementing the TLSTM-MIB will implement
the SNMPv2-MIB [RFC3418], the SNMP-FRAMEWORK-MIB [RFC3411], the SNMP- the SNMPv2-MIB [RFC3418], the SNMP-FRAMEWORK-MIB [RFC3411], the SNMP-
TARGET-MIB [RFC3413], the SNMP-NOTIFICATION-MIB [RFC3413] and the TARGET-MIB [RFC3413], the SNMP-NOTIFICATION-MIB [RFC3413] and the
SNMP-VIEW-BASED-ACM-MIB [RFC3415]. SNMP-VIEW-BASED-ACM-MIB [RFC3415].
The TLSTM-MIB module contained in this document is for managing TLS The TLSTM-MIB module contained in this document is for managing TLS
Transport Model information. Transport Model information.
6.5.1. MIB Modules Required for IMPORTS 6.5.1. MIB Modules Required for IMPORTS
The TLSTM-MIB module imports items from SNMPV2-SMI [RFC2578], The TLSTM-MIB module imports items from SNMPv2-SMI [RFC2578],
SNMPV2-TC [RFC2579], SNMP-FRAMEWORK-MIB [RFC3411], SNMP-TARGET-MIB SNMPv2-TC [RFC2579], SNMP-FRAMEWORK-MIB [RFC3411], SNMP-TARGET-MIB
[RFC3413] and SNMP-CONF [RFC2580]. [RFC3413] and SNMPv2-CONF [RFC2580].
7. MIB Module Definition 7. MIB Module Definition
TLSTM-MIB DEFINITIONS ::= BEGIN TLSTM-MIB DEFINITIONS ::= BEGIN
IMPORTS IMPORTS
MODULE-IDENTITY, OBJECT-TYPE, MODULE-IDENTITY, OBJECT-TYPE,
OBJECT-IDENTITY, snmpModules, snmpDomains, OBJECT-IDENTITY, snmpModules, snmpDomains,
Counter32, Unsigned32 Counter32, Unsigned32, NOTIFICATION-TYPE
FROM SNMPv2-SMI FROM SNMPv2-SMI
TEXTUAL-CONVENTION, TimeStamp, RowStatus, StorageType TEXTUAL-CONVENTION, TimeStamp, RowStatus, StorageType
FROM SNMPv2-TC FROM SNMPv2-TC
MODULE-COMPLIANCE, OBJECT-GROUP MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP
FROM SNMPv2-CONF FROM SNMPv2-CONF
SnmpAdminString SnmpAdminString
FROM SNMP-FRAMEWORK-MIB FROM SNMP-FRAMEWORK-MIB
snmpTargetParamsName, snmpTargetAddrName snmpTargetParamsName, snmpTargetAddrName
FROM SNMP-TARGET-MIB FROM SNMP-TARGET-MIB
; ;
tlstmMIB MODULE-IDENTITY tlstmMIB MODULE-IDENTITY
LAST-UPDATED "200807070000Z" LAST-UPDATED "200807070000Z"
ORGANIZATION " " ORGANIZATION "ISMS Working Group"
CONTACT-INFO "WG-EMail: CONTACT-INFO "WG-EMail: isms@lists.ietf.org
Subscribe: Subscribe: isms-request@lists.ietf.org
Chairs: Chairs:
Juergen Schoenwaelder
Jacobs University Bremen
Campus Ring 1
28725 Bremen
Germany
+49 421 200-3587
j.schoenwaelder@jacobs-university.de
Russ Mundy
SPARTA, Inc.
7110 Samuel Morse Drive
Columbia, MD 21046
USA
Co-editors: Co-editors:
" Wes Hardaker
Sparta, Inc.
P.O. Box 382
Davis, CA 95617
USA
ietf@hardakers.net
"
DESCRIPTION "The TLS Transport Model MIB DESCRIPTION "
The TLS Transport Model MIB
Copyright (c) 2009 IETF Trust and the persons
identified as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, are permitted provided that the
following conditions are met:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials
provided with the distribution.
- Neither the name of Internet Society, IETF or IETF Trust,
nor the names of specific contributors, may be used to endorse
or promote products derived from this software without
specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
This version of this MIB module is part of RFC XXXX;
see the RFC itself for full legal notices."
Copyright (C) The IETF Trust (2008). This
version of this MIB module is part of RFC XXXX;
see the RFC itself for full legal notices."
-- NOTE to RFC editor: replace XXXX with actual RFC number -- NOTE to RFC editor: replace XXXX with actual RFC number
-- for this document and remove this note -- for this document and remove this note
REVISION "200807070000Z" REVISION "200807070000Z"
DESCRIPTION "The initial version, published in RFC XXXX." DESCRIPTION "The initial version, published in RFC XXXX."
-- NOTE to RFC editor: replace XXXX with actual RFC number -- NOTE to RFC editor: replace XXXX with actual RFC number
-- for this document and remove this note -- for this document and remove this note
::= { snmpModules xxxx } ::= { snmpModules xxxx }
-- RFC Ed.: replace xxxx with IANA-assigned number and -- RFC Ed.: replace xxxx with IANA-assigned number and
-- remove this note -- remove this note
-- ************************************************ -- ************************************************
-- subtrees of the TLSTM-MIB
-- ************************************************ -- ************************************************
tlstmNotifications OBJECT IDENTIFIER ::= { tlstmMIB 0 } tlstmNotifications OBJECT IDENTIFIER ::= { tlstmMIB 0 }
tlstmObjects OBJECT IDENTIFIER ::= { tlstmMIB 1 } tlstmObjects OBJECT IDENTIFIER ::= { tlstmMIB 1 }
tlstmConformance OBJECT IDENTIFIER ::= { tlstmMIB 2 } tlstmConformance OBJECT IDENTIFIER ::= { tlstmMIB 2 }
-- ************************************************ -- ************************************************
-- tlstmObjects - Objects
-- ************************************************ -- ************************************************
snmpTLSDomain OBJECT-IDENTITY snmpTLSDomain OBJECT-IDENTITY
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The SNMP over TLS transport domain. The corresponding "The SNMP over TLS transport domain. The corresponding
transport address is of type SnmpTLSAddress. transport address is of type SnmpTLSAddress.
The securityName prefix to be associated with the The securityName prefix to be associated with the
snmpTLSDomain is 'tls'. This prefix may be used by snmpTLSDomain is 'tls'. This prefix may be used by
security models or other components to identify what secure security models or other components to identify which secure
transport infrastructure authenticated a securityName." transport infrastructure authenticated a securityName."
::= { snmpDomains xx } ::= { snmpDomains xx }
-- RFC Ed.: replace xx with IANA-assigned number and -- RFC Ed.: replace xx with IANA-assigned number and
-- remove this note -- remove this note
-- RFC Ed.: replace 'tls' with the actual IANA assigned prefix string -- RFC Ed.: replace 'tls' with the actual IANA assigned prefix string
-- if 'tls' is not assigned to this document. -- if 'tls' is not assigned to this document.
skipping to change at page 32, line 18 skipping to change at page 33, line 32
"The SNMP over DTLS/UDP transport domain. The corresponding "The SNMP over DTLS/UDP transport domain. The corresponding
transport address is of type SnmpDTLSUDPAddress. transport address is of type SnmpDTLSUDPAddress.
When an SNMP entity uses the snmpDTLSUDPDomain transport When an SNMP entity uses the snmpDTLSUDPDomain transport
model, it must be capable of accepting messages up to model, it must be capable of accepting messages up to
the maximum MTU size for an interface it supports, minus the the maximum MTU size for an interface it supports, minus the
needed IP, UDP, DTLS and other protocol overheads. needed IP, UDP, DTLS and other protocol overheads.
The securityName prefix to be associated with the The securityName prefix to be associated with the
snmpDTLSUDPDomain is 'dudp'. This prefix may be used by snmpDTLSUDPDomain is 'dudp'. This prefix may be used by
security models or other components to identify what secure security models or other components to identify which secure
transport infrastructure authenticated a securityName." transport infrastructure authenticated a securityName."
::= { snmpDomains yy } ::= { snmpDomains yy }
-- RFC Ed.: replace yy with IANA-assigned number and -- RFC Ed.: replace yy with IANA-assigned number and
-- remove this note -- remove this note
-- RFC Ed.: replace 'dudp' with the actual IANA assigned prefix string -- RFC Ed.: replace 'dudp' with the actual IANA assigned prefix string
-- if 'dtls' is not assigned to this document. -- if 'dtls' is not assigned to this document.
snmpDTLSSCTPDomain OBJECT-IDENTITY snmpDTLSSCTPDomain OBJECT-IDENTITY
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The SNMP over DTLS/SCTP transport domain. The corresponding "The SNMP over DTLS/SCTP transport domain. The corresponding
transport address is of type SnmpDTLSSCTPAddress. transport address is of type SnmpDTLSSCTPAddress.
When an SNMP entity uses the snmpDTLSSCTPDomain transport
model, it must be capable of accepting messages up to
the maximum MTU size for an interface it supports, minus the
needed IP, SCTP, DTLS and other protocol overheads.
The securityName prefix to be associated with the The securityName prefix to be associated with the
snmpDTLSSCTPDomain is 'dsct'. This prefix may be used by snmpDTLSSCTPDomain is 'dsct'. This prefix may be used by
security models or other components to identify what secure security models or other components to identify which secure
transport infrastructure authenticated a securityName." transport infrastructure authenticated a securityName."
::= { snmpDomains zz } ::= { snmpDomains zz }
-- RFC Ed.: replace zz with IANA-assigned number and -- RFC Ed.: replace zz with IANA-assigned number and
-- remove this note -- remove this note
-- RFC Ed.: replace 'dsct' with the actual IANA assigned prefix string -- RFC Ed.: replace 'dsct' with the actual IANA assigned prefix string
-- if 'dtls' is not assigned to this document. -- if 'dtls' is not assigned to this document.
SnmpTLSAddress ::= TEXTUAL-CONVENTION SnmpTLSAddress ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1a" DISPLAY-HINT "1a"
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"Represents a TCP connection address for an IPv4 address, an "Represents a TCP connection address for an IPv4 address, an
IPv6 address or an ASCII encoded host name and port number. IPv6 address or an US-US-ASCII encoded hostname and port number.
The hostname must be encoded in ASCII, as specified in RFC3490
(Internationalizing Domain Names in Applications) followed by
a colon ':' (ASCII character 0x3A) and a decimal port number
in ASCII. The name SHOULD be fully qualified whenever
possible.
An IPv4 address must be a dotted decimal format followed by a An IPv4 address must be in dotted decimal format followed by a
colon ':' (ASCII character 0x3A) and a decimal port number in colon ':' (US-ASCII character 0x3A) and a decimal port number
ASCII. in US-ASCII.
An IPv6 address must be a colon separated format, surrounded An IPv6 address must be a colon separated format, surrounded
by square brackets (ASCII characters 0x5B and 0x5D), followed by square brackets ('[', US-ASCII character 0x5B, and ']',
by a colon ':' (ASCII character 0x3A) and a decimal port US-ASCII character 0x5D), followed by a colon ':' (US-ASCII
number in ASCII. character 0x3A) and a decimal port number in US-ASCII.
A hostname is always in US-US-ASCII (as per RFC1033);
internationalized hostnames are encoded in US-US-ASCII as
specified in RFC 3490. The hostname is followed by a colon
':' (US-US-ASCII character 0x3A) and a decimal port number in
US-US-ASCII. The name SHOULD be fully qualified whenever
possible.
Values of this textual convention may not be directly usable Values of this textual convention may not be directly usable
as transport-layer addressing information, and may require as transport-layer addressing information, and may require
run-time resolution. As such, applications that write them run-time resolution. As such, applications that write them
must be prepared for handling errors if such values are not must be prepared for handling errors if such values are not
supported, or cannot be resolved (if resolution occurs at the supported, or cannot be resolved (if resolution occurs at the
time of the management operation). time of the management operation).
The DESCRIPTION clause of TransportAddress objects that may The DESCRIPTION clause of TransportAddress objects that may
have snmpTLSAddress values must fully describe how (and have snmpTLSAddress values must fully describe how (and
skipping to change at page 33, line 48 skipping to change at page 35, line 13
versa. versa.
This textual convention SHOULD NOT be used directly in object This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific definitions since it restricts addresses to a specific
format. However, if it is used, it MAY be used either on its format. However, if it is used, it MAY be used either on its
own or in conjunction with TransportAddressType or own or in conjunction with TransportAddressType or
TransportDomain as a pair. TransportDomain as a pair.
When this textual convention is used as a syntax of an index When this textual convention is used as a syntax of an index
object, there may be issues with the limit of 128 object, there may be issues with the limit of 128
sub-identifiers specified in SMIv2, STD 58. It is RECOMMENDED sub-identifiers specified in SMIv2 (STD 58). It is RECOMMENDED
that all MIB documents using this textual convention make that all MIB documents using this textual convention make
explicit any limitations on index component lengths that explicit any limitations on index component lengths that
management software must observe. This may be done either by management software must observe. This may be done either by
including SIZE constraints on the index components or by including SIZE constraints on the index components or by
specifying applicable constraints in the conceptual row specifying applicable constraints in the conceptual row
DESCRIPTION clause or in the surrounding documentation." DESCRIPTION clause or in the surrounding documentation."
REFERENCE
"RFC 1033: DOMAIN ADMINISTRATORS OPERATIONS GUIDE
RFC 3490: Internationalizing Domain Names in Applications
RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2
"
SYNTAX OCTET STRING (SIZE (1..255)) SYNTAX OCTET STRING (SIZE (1..255))
SnmpDTLSUDPAddress ::= TEXTUAL-CONVENTION SnmpDTLSUDPAddress ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1a" DISPLAY-HINT "1a"
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"Represents a UDP connection address for an IPv4 address, an "Represents a UDP connection address for an IPv4 address, an
IPv6 address or an ASCII encoded host name and port number. IPv6 address or an US-ASCII encoded hostname and port number.
The hostname must be encoded in ASCII, as specified in RFC3490
(Internationalizing Domain Names in Applications) followed by
a colon ':' (ASCII character 0x3A) and a decimal port number
in ASCII. The name SHOULD be fully qualified whenever
possible.
An IPv4 address must be a dotted decimal format followed by a An IPv4 address must be a dotted decimal format followed by a
colon ':' (ASCII character 0x3A) and a decimal port number in colon ':' (US-ASCII character 0x3A) and a decimal port number in
ASCII. US-ASCII.
An IPv6 address must be a colon separated format, surrounded An IPv6 address must be a colon separated format, surrounded
by square brackets (ASCII characters 0x5B and 0x5D), followed by square brackets ('[', US-ASCII character 0x5B, and ']',
by a colon ':' (ASCII character 0x3A) and a decimal port US-ASCII character 0x5D), followed by a colon ':' (US-ASCII
number in ASCII. character 0x3A) and a decimal port number in US-ASCII.
A hostname is always in US-US-ASCII (as per RFC1033);
internationalized hostnames are encoded in US-US-ASCII as
specified in RFC 3490. The hostname is followed by a colon
':' (US-US-ASCII character 0x3A) and a decimal port number in
US-US-ASCII. The name SHOULD be fully qualified whenever
possible.
Values of this textual convention may not be directly usable Values of this textual convention may not be directly usable
as transport-layer addressing information, and may require as transport-layer addressing information, and may require
run-time resolution. As such, applications that write them run-time resolution. As such, applications that write them
must be prepared for handling errors if such values are not must be prepared for handling errors if such values are not
supported, or cannot be resolved (if resolution occurs at the supported, or cannot be resolved (if resolution occurs at the
time of the management operation). time of the management operation).
The DESCRIPTION clause of TransportAddress objects that may The DESCRIPTION clause of TransportAddress objects that may
have snmpDTLSUDPAddress values must fully describe how (and have snmpDTLSUDPAddress values must fully describe how (and
skipping to change at page 34, line 51 skipping to change at page 36, line 22
versa. versa.
This textual convention SHOULD NOT be used directly in object This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific definitions since it restricts addresses to a specific
format. However, if it is used, it MAY be used either on its format. However, if it is used, it MAY be used either on its
own or in conjunction with TransportAddressType or own or in conjunction with TransportAddressType or
TransportDomain as a pair. TransportDomain as a pair.
When this textual convention is used as a syntax of an index When this textual convention is used as a syntax of an index
object, there may be issues with the limit of 128 object, there may be issues with the limit of 128
sub-identifiers specified in SMIv2, STD 58. It is RECOMMENDED sub-identifiers specified in SMIv2 (STD 58). It is RECOMMENDED
that all MIB documents using this textual convention make that all MIB documents using this textual convention make
explicit any limitations on index component lengths that explicit any limitations on index component lengths that
management software must observe. This may be done either by management software must observe. This may be done either by
including SIZE constraints on the index components or by including SIZE constraints on the index components or by
specifying applicable constraints in the conceptual row specifying applicable constraints in the conceptual row
DESCRIPTION clause or in the surrounding documentation." DESCRIPTION clause or in the surrounding documentation."
REFERENCE
"RFC 1033: DOMAIN ADMINISTRATORS OPERATIONS GUIDE
RFC 3490: Internationalizing Domain Names in Applications
RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
RFC 4347: Datagram Transport Layer Security
RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2
"
SYNTAX OCTET STRING (SIZE (1..255)) SYNTAX OCTET STRING (SIZE (1..255))
SnmpDTLSSCTPAddress ::= TEXTUAL-CONVENTION SnmpDTLSSCTPAddress ::= TEXTUAL-CONVENTION
DISPLAY-HINT "1a" DISPLAY-HINT "1a"
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"Represents a SCTP connection address for an IPv4 address, an "Represents a SCTP connection address for an IPv4 address, an
IPv6 address or an ASCII encoded host name and port number. IPv6 address or an US-ASCII encoded hostname and port number.
The hostname must be encoded in ASCII, as specified in RFC3490
(Internationalizing Domain Names in Applications) followed by
a colon ':' (ASCII character 0x3A) and a decimal port number
in ASCII. The name SHOULD be fully qualified whenever
possible.
An IPv4 address must be a dotted decimal format followed by a An IPv4 address must be a dotted decimal format followed by a
colon ':' (ASCII character 0x3A) and a decimal port number in colon ':' (US-ASCII character 0x3A) and a decimal port number in
ASCII. US-ASCII.
An IPv6 address must be a colon separated format, surrounded An IPv6 address must be a colon separated format, surrounded
by square brackets (ASCII characters 0x5B and 0x5D), followed by square brackets ('[', US-ASCII character 0x5B, and ']',
by a colon ':' (ASCII character 0x3A) and a decimal port US-ASCII character 0x5D), followed by a colon ':' (US-ASCII
number in ASCII. character 0x3A) and a decimal port number in US-ASCII.
A hostname is always in US-US-ASCII (as per RFC1033);
internationalized hostnames are encoded in US-US-ASCII as
specified in RFC 3490. The hostname is followed by a colon
':' (US-US-ASCII character 0x3A) and a decimal port number in
US-US-ASCII. The name SHOULD be fully qualified whenever
possible.
Values of this textual convention may not be directly usable Values of this textual convention may not be directly usable
as transport-layer addressing information, and may require as transport-layer addressing information, and may require
run-time resolution. As such, applications that write them run-time resolution. As such, applications that write them
must be prepared for handling errors if such values are not must be prepared for handling errors if such values are not
supported, or cannot be resolved (if resolution occurs at the supported, or cannot be resolved (if resolution occurs at the
time of the management operation). time of the management operation).
The DESCRIPTION clause of TransportAddress objects that may The DESCRIPTION clause of TransportAddress objects that may
have snmpDTLSSCTPAddress values must fully describe how (and have snmpDTLSSCTPAddress values must fully describe how (and
skipping to change at page 36, line 7 skipping to change at page 37, line 33
versa. versa.
This textual convention SHOULD NOT be used directly in object This textual convention SHOULD NOT be used directly in object
definitions since it restricts addresses to a specific definitions since it restricts addresses to a specific
format. However, if it is used, it MAY be used either on its format. However, if it is used, it MAY be used either on its
own or in conjunction with TransportAddressType or own or in conjunction with TransportAddressType or
TransportDomain as a pair. TransportDomain as a pair.
When this textual convention is used as a syntax of an index When this textual convention is used as a syntax of an index
object, there may be issues with the limit of 128 object, there may be issues with the limit of 128
sub-identifiers specified in SMIv2, STD 58. It is RECOMMENDED sub-identifiers specified in SMIv2 (STD 58). It is RECOMMENDED
that all MIB documents using this textual convention make that all MIB documents using this textual convention make
explicit any limitations on index component lengths that explicit any limitations on index component lengths that
management software must observe. This may be done either by management software must observe. This may be done either by
including SIZE constraints on the index components or by including SIZE constraints on the index components or by
specifying applicable constraints in the conceptual row specifying applicable constraints in the conceptual row
DESCRIPTION clause or in the surrounding documentation." DESCRIPTION clause or in the surrounding documentation."
SYNTAX OCTET STRING (SIZE (1..255)) SYNTAX OCTET STRING (SIZE (1..255))
FingerprintType ::= TEXTUAL-CONVENTION Fingerprint ::= TEXTUAL-CONVENTION
STATUS current DISPLAY-HINT "1x:254x"
DESCRIPTION
"Identifies an algorithm type that can be used to uniquely
reference other data of a potentially arbitrary length. If a
hashing algorithm is used, then the algorithm should be
sufficiently robust enough and it's output long enough that
hash-collisions should not occur. Other mechanisms of defining
fingerprints include other forms of unique identification such
as serial numbers or concatenated combinations of data such
that the result is sufficiently unique.
Objects making use of this TEXTUAL-CONVENTION SHOULD be
accompanied by another object or objects of type
FingerprintValue.
This TEXTUAL-CONVENTION SHOULD NOT be used as a form of
cryptographic verification. Two matching sets of
FingerprintType/FingerprintValue should not be considered
authenticated. These TEXTUAL-CONVENTIONs are only intended for
use as a reference to a stored copy of a longer data source and
the full data sources need to be compared to assure collisions
have not resulted."
SYNTAX OBJECT IDENTIFIER
FingerprintValue ::= TEXTUAL-CONVENTION
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A Fingerprint value that can be used to uniquely reference "A Fingerprint value that can be used to uniquely reference
other data of potentially arbitrary length. other data of potentially arbitrary length.
Objects making use of this TEXTUAL-CONVENTION SHOULD always be A Fingerprint value is composed of a 1-octet hashing algorithm
accompanied by a FingerprintType object that dictates the type. The octet value encoded is taken from the IANA TLS
format of values stored in objects of type FingerprintValue. HashAlgorithm Registry (RFC5246). The remaining octets are
filled using the results of the hashing algorithm.
This TEXTUAL-CONVENTION SHOULD NOT be used as a form of This TEXTUAL-CONVENTION SHOULD NOT be used as a form of
cryptographic verification. Two matching sets of cryptographic verification and a data source with a matching
FingerprintType/FingerprintValue should not be considered fingerprint should not be considered authenticated because the
authenticated. These TEXTUAL-CONVENTIONs are only intended for value matches. This TEXTUAL-CONVENTION is only intended for
use as a reference to a stored copy of a longer data source and use as a reference to a stored copy of a longer data source.
the full data sources need to be compared to assure collisions The contents of full data source referenced by this fingerprint
have not resulted." needs to be compared against to assure collisions have not
SYNTAX OCTET STRING resulted."
REFERENCE
"RFC 1033: DOMAIN ADMINISTRATORS OPERATIONS GUIDE
tlstmFingerprintTypes OBJECT IDENTIFIER ::= { tlstmObjects 1 } RFC 3490: Internationalizing Domain Names in Applications
RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
tlstmMD5 OBJECT-IDENTITY RFC 4347: Datagram Transport Layer Security
STATUS current RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2
DESCRIPTION "
"An identifier for the MD5 hashing algorithm to be used with SYNTAX OCTET STRING (SIZE (1..255))
FingerprintType objects. The resulting value to be placed into
the corresponding FingerprintValue object should be a
full-length MD5 hash (16 octets)."
::= { tlstmFingerprintTypes 1 }
tlstmSHA1 OBJECT-IDENTITY
STATUS current
DESCRIPTION
"An identifier for the SHA1 hashing algorithm to be used with
FingerprintType objects. The resulting value to be placed into
the corresponding FingerprintValue object should be a
full-length SHA1 hash (20 octets)."
::= { tlstmFingerprintTypes 2 }
tlstmSHA256 OBJECT-IDENTITY
STATUS current
DESCRIPTION
"An identifier for the SHA256 hashing algorithm to be used with
FingerprintType objects. The resulting value to be placed into
the corresponding FingerprintValue object should be a
full-length SHA256 hash (32 octets)."
::= { tlstmFingerprintTypes 3 }
-- The tlstmSession Group -- The tlstmSession Group
tlstmSession OBJECT IDENTIFIER ::= { tlstmObjects 2 } tlstmSession OBJECT IDENTIFIER ::= { tlstmObjects 1 }
tlstmSessionOpens OBJECT-TYPE tlstmSessionOpens OBJECT-TYPE
SYNTAX Counter32 SYNTAX Counter32
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The number of times an openSession() request has been "The number of times an openSession() request has been
executed as an (D)TLS client, whether it succeeded or failed." executed as an (D)TLS client, whether it succeeded or failed."
::= { tlstmSession 1 } ::= { tlstmSession 1 }
skipping to change at page 39, line 23 skipping to change at page 40, line 4
SYNTAX Counter32 SYNTAX Counter32
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The number of times (D)TLS processing resulted in a message "The number of times (D)TLS processing resulted in a message
being discarded because it failed its integrity test, being discarded because it failed its integrity test,
decryption processing or other (D)TLS processing." decryption processing or other (D)TLS processing."
::= { tlstmSession 7 } ::= { tlstmSession 7 }
-- Configuration Objects -- Configuration Objects
tlstmConfig OBJECT IDENTIFIER ::= { tlstmObjects 2 }
tlstmConfig OBJECT IDENTIFIER ::= { tlstmObjects 3 }
-- Certificate mapping -- Certificate mapping
tlstmCertificateMapping OBJECT IDENTIFIER ::= { tlstmConfig 1 } tlstmCertificateMapping OBJECT IDENTIFIER ::= { tlstmConfig 1 }
tlstmCertToSNCount OBJECT-TYPE tlstmCertToSNCount OBJECT-TYPE
SYNTAX Unsigned32 SYNTAX Unsigned32
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A count of the number of entries in the "A count of the number of entries in the tlstmCertToSNTable"
tlstmCertToSNTable"
::= { tlstmCertificateMapping 1 } ::= { tlstmCertificateMapping 1 }
tlstmCertToSNTableLastChanged OBJECT-TYPE tlstmCertToSNTableLastChanged OBJECT-TYPE
SYNTAX TimeStamp SYNTAX TimeStamp
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The value of sysUpTime.0 when the tlstmCertToSNTable "The value of sysUpTime.0 when the tlstmCertToSNTable
was last modified through any means, or 0 if it has not been was last modified through any means, or 0 if it has not been
modified since the command responder was started." modified since the command responder was started."
skipping to change at page 40, line 16 skipping to change at page 40, line 43
"A table listing the X.509 certificates known to the entity "A table listing the X.509 certificates known to the entity
and the associated method for determining the SNMPv3 security and the associated method for determining the SNMPv3 security
name from a certificate. name from a certificate.
On an incoming (D)TLS/SNMP connection the client's presented On an incoming (D)TLS/SNMP connection the client's presented
certificate must be examined and validated based on an certificate must be examined and validated based on an
established trusted path from a CA certificate or self-signed established trusted path from a CA certificate or self-signed
public certificate (e.g. RFC5280). This table provides a public certificate (e.g. RFC5280). This table provides a
mapping from a validated certificate to a SNMPv3 securityName. mapping from a validated certificate to a SNMPv3 securityName.
This table does not provide any mechanisms for uploading This table does not provide any mechanisms for uploading
trusted certificates and the transfer of any needed trusted trusted certificates; the transfer of any needed trusted
certificates for path validation is expected to occur through certificates for path validation is expected to occur through
an out-of-band transfer. an out-of-band transfer.
Once the authenticity of a certificate has been verified, this Once the authenticity of a certificate has been verified, this
table is consulted to determine the appropriate securityName table is consulted to determine the appropriate securityName
to identify with the remote connection. This is done by to identify with the remote connection. This is done by
considering each active row from this table in prioritized considering each active row from this table in prioritized
order according to its tlstmCertToSNID value. Each row's order according to its tlstmCertToSNID value. Each row's
tlstmCertToSNHashType and tlstmCertToSNHashValue values tlstmCertToSNFingerprint value determines whether the row is a
determine whether the row is a match for the incoming match for the incoming connection:
connection:
1) If the row's tlstmCertToSNHashType and 1) If the row's tlstmCertToSNFingerprint value identifies
tlstmCertToSNHashValue values identify the presented the presented certificate and the contents of the
certificate and the contents of the presented presented certificate match a locally cached copy of
certificate match a locally cached copy of the the certificate then consider the row as a successful
certificate then consider the row as a successful
match. match.
2) If the row's tlstmCertToSNHashType and 2) If the row's tlstmCertToSNFingerprint value identifies
tlstmCertToSNHashValue values identify a locally held a locally held copy of a trusted CA certificate and
copy of a trusted CA certificate and that CA that CA certificated was used to validate the path to
certificated was used to validate the presented the presented certificate then consider the row as a
certificate then consider the row as a successful successful match.
match.
Once a matching row has been found, the tlstmCertToSNMapType Once a matching row has been found, the tlstmCertToSNMapType
value can be used to determine how the securityName to value can be used to determine how the securityName to
associate with the session should be determined. See the associate with the session should be determined. See the
tlstmCertToSNMapType column's DESCRIPTION for details on tlstmCertToSNMapType column's DESCRIPTION for details on
determining the securityName value. If it is impossible to determining the securityName value. If it is impossible to
determine the resulting securityName from the row's data determine a securityName from the row's data combined with the
combined with the data presented in the certificate then data presented in the certificate then additional rows MUST be
additional rows MUST be searched looking for another potential searched looking for another potential match. If a resulting
match. If a resulting securityName mapped from a given row is securityName mapped from a given row is not compatible with
not compatible with the needed requirements of a legal the needed requirements of a securityName (e.g., VACM imposes
securityName (i.e., VACM imposes a 32-octet-maximum length) a 32-octet-maximum length and the certificate derived
then it must be considered an invalid match and additional securityName could be longer) then it must be considered an
rows MUST be searched looking for another potential match. invalid match and additional rows MUST be searched looking for
another potential match.
Missing values of tlstmCertToSNID are acceptable and Missing values of tlstmCertToSNID are acceptable and
implementations should continue to the next highest numbered implementations should continue to the next highest numbered
row. E.G., the table may legally contain only two rows with row. E.G., the table may legally contain only two rows with
tlstmCertToSNID values of 10 and 20. tlstmCertToSNID values of 10 and 20.
Users are encouraged to make use of certificates with Users are encouraged to make use of certificates with
subjectAltName fields that can be used as securityNames so subjectAltName fields that can be used as securityNames so
that a single root CA certificate can allow all child that a single root CA certificate can allow all child
certificate's subjectAltName to map directly to a securityName certificate's subjectAltName to map directly to a securityName
skipping to change at page 41, line 35 skipping to change at page 42, line 12
a securityName is also possible but requires one entry in the a securityName is also possible but requires one entry in the
table per securityName and requires more management operations table per securityName and requires more management operations
to completely configure a device." to completely configure a device."
::= { tlstmCertificateMapping 3 } ::= { tlstmCertificateMapping 3 }
tlstmCertToSNEntry OBJECT-TYPE tlstmCertToSNEntry OBJECT-TYPE
SYNTAX TlstmCertToSNEntry SYNTAX TlstmCertToSNEntry
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A row in the tlstmCertToSNTable that specifies a "A row in the tlstmCertToSNTable that specifies a mapping for
mapping for an incoming (D)TLS certificate to a securityName an incoming (D)TLS certificate to a securityName to use for a
to use for a connection." connection."
INDEX { tlstmCertToSNID } INDEX { tlstmCertToSNID }
::= { tlstmCertToSNTable 1 } ::= { tlstmCertToSNTable 1 }
TlstmCertToSNEntry ::= SEQUENCE { TlstmCertToSNEntry ::= SEQUENCE {
tlstmCertToSNID Unsigned32, tlstmCertToSNID Unsigned32,
tlstmCertToSNHashType FingerprintType, tlstmCertToSNFingerprint Fingerprint,
tlstmCertToSNHashValue FingerprintValue,
tlstmCertToSNMapType INTEGER, tlstmCertToSNMapType INTEGER,
tlstmCertToSNSecurityName SnmpAdminString, tlstmCertToSNSecurityName SnmpAdminString,
tlstmCertToSNSANType INTEGER, tlstmCertToSNSANType INTEGER,
tlstmCertToSNStorageType StorageType, tlstmCertToSNStorageType StorageType,
tlstmCertToSNRowStatus RowStatus tlstmCertToSNRowStatus RowStatus
} }
tlstmCertToSNID OBJECT-TYPE tlstmCertToSNID OBJECT-TYPE
SYNTAX Unsigned32 SYNTAX Unsigned32
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A unique, prioritized index for a given certificate entry." "A unique, prioritized index for the given entry."
::= { tlstmCertToSNEntry 1 } ::= { tlstmCertToSNEntry 1 }
tlstmCertToSNHashType OBJECT-TYPE tlstmCertToSNFingerprint OBJECT-TYPE
SYNTAX FingerprintType SYNTAX Fingerprint
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The hash algorithm to use when applying a hash to a X.509
certificate for purposes of referring to it from the
tlstmCertToSNHashValue column."
DEFVAL { tlstmSHA256 }
::= { tlstmCertToSNEntry 2 }
tlstmCertToSNHashValue OBJECT-TYPE
SYNTAX FingerprintValue
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A cryptographic hash of a X.509 certificate. The results of "A cryptographic hash of a X.509 certificate. The results of
a successful matching fingerprint is dictated by the a successful matching fingerprint to either the trusted CA in
tlstmCertToSNMapType column. A match of the fingerprint MUST the certificate validation path or to the certificate itself
only be considered successful if both the fingerprint type is dictated by the tlstmCertToSNMapType column."
(tlstmCertToSNMapType) and fingerprint value ::= { tlstmCertToSNEntry 2 }
(tlstmCertToSNHashValue) columns have been found equal to the
type and value of the certificate being checked."
::= { tlstmCertToSNEntry 3 }
tlstmCertToSNMapType OBJECT-TYPE tlstmCertToSNMapType OBJECT-TYPE
SYNTAX INTEGER { specified(1), bySubjectAltName(2), byCN(3) } SYNTAX INTEGER { specified(1), bySubjectAltName(2), byCN(3) }
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The mapping type used to obtain the securityName from the "The mapping type used to obtain the securityName from the
certificate. The possible values of use and their usage certificate. The possible values of use and their usage
methods are defined as follows: methods are defined as follows:
specified(1): The securityName that should be used to specified(1): The securityName that should be used to
associate with the session is directly associate with the session is directly specified
specified in the tlstmCertToSNecurityName column in the tlstmCertToSNecurityName column from this
from this table. table. Note: The tlstmCertToSNSecurityName
column's value is ignored for all other
tlstmCertToSNMapType values.
bySubjectAltName(2): bySubjectAltName(2):
The securityName that should be used to The securityName that should be used to
associate with the session should be taken from associate with the session should be taken from
the subjectAltName(s) portion of the client's the subjectAltName(s) portion of the client's
X.509 certificate. The subjectAltName used MUST X.509 certificate. The subjectAltName used MUST
be the first encountered subjectAltName type be the first encountered subjectAltName type
indicated by the tlstmCertToSNSANType column. indicated by the tlstmCertToSNSANType column.
If no subjectAltName of the given type is found
within the certificate then additional rows in If the resulting mapped value from the
the tlstmCertToSNTable must be searched. subjectAltName component is not compatible with
the needed requirements of a securityName (e.g.,
VACM imposes a 32-octet-maximum length and the
certificate derived securityName could be
longer) then the next appropriate subjectAltName
of the correct type should be used if available.
If no appropriate subjectAltName of the given
type is found within the certificate then
additional rows in the tlstmCertToSNTable must
be searched for additional
tlstmCertToSNFingerprint matches.
byCN(3): The securityName that should be used to byCN(3): The securityName that should be used to
associate with the session should be taken from associate with the session should be taken from
the CommonName portion of the Subject field from the CommonName portion of the Subject field from
the client's presented X.509 certificate. the client's presented X.509 certificate.
If the resulting mapped value from the subjectAltName If the value of the CommonName component is not
component is not compatible with the needed requirements of a compatible with the needed requirements of a
legal securityName (i.e., VACM imposes a 32-octet-maximum securityName (e.g., VACM imposes a
length) then the next appropriate subjectAltName of the 32-octet-maximum length and the certificate
correct type should be used if available. derived securityName could be longer) then
additional rows in the tlstmCertToSNTable must
If this object is of type bySubjectAltName(2) and no be searched for additional
subjectAltName value can be found that meets the requirements tlstmCertToSNFingerprint matches."
of this object then any additional rows in the
tlstmCertToSNTable must be searched.
If this object is of type byCN(3) and the CommonName value
does not meet the requirements of this object then any
additional rows in the tlstmCertToSNTable must be searched."
DEFVAL { specified } DEFVAL { specified }
::= { tlstmCertToSNEntry 4 } ::= { tlstmCertToSNEntry 3 }
tlstmCertToSNSecurityName OBJECT-TYPE tlstmCertToSNSecurityName OBJECT-TYPE
SYNTAX SnmpAdminString (SIZE(0..32)) SYNTAX SnmpAdminString (SIZE(0..32))
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The securityName that the session should use if the "The securityName that the session should use if the
tlstmCertToSNMapType is set to specified(1), otherwise the tlstmCertToSNMapType is set to specified(1), otherwise the
value in this column should be ignored. If value in this column should be ignored. If
tlstmCertToSNMapType is set to specifed(1) and this column tlstmCertToSNMapType is set to specifed(1) and this column
contains a zero-length string (which is not a legal contains a zero-length string (which is not a legal
securityName value) this row is effectively disabled and the securityName value) this row is effectively disabled and the
match will not be considered successful and other rows in the match will not be considered successful and other rows in the
table will need to be searched." table will need to be searched for a proper match."
DEFVAL { "" } DEFVAL { "" }
::= { tlstmCertToSNEntry 5 } ::= { tlstmCertToSNEntry 4 }
tlstmCertToSNSANType OBJECT-TYPE tlstmCertToSNSANType OBJECT-TYPE
SYNTAX INTEGER { any(1), rfc822Name(2), dNSName(3), SYNTAX INTEGER { any(1), rfc822Name(2), dNSName(3),
ipAddress(4), otherName(5) } ipAddress(4), otherName(5) }
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"Specifies the subjectAltName type that may be used to extract "Specifies the subjectAltName type that may be used to extract
the securityName from. the securityName from.
skipping to change at page 44, line 34 skipping to change at page 44, line 50
Values for type ipAddress(4) are converted to a valid Values for type ipAddress(4) are converted to a valid
securityName by: securityName by:
1) for IPv4 the value is converted into a decimal dotted 1) for IPv4 the value is converted into a decimal dotted
quad address (e.g. '192.0.2.1') quad address (e.g. '192.0.2.1')
2) for IPv6 addresses the value is converted into a 2) for IPv6 addresses the value is converted into a
32-character hexadecimal string without any colon 32-character hexadecimal string without any colon
separators. separators.
Note that the resulting length is the maximum length
supported by the View-Based Access Control Model
(VACM). Note that using both the Transport Security
Model's support for transport prefixes (see the
SNMP-TSM-MIB::snmpTsmConfigurationUsePrefix object for
details) will result in securityName lengths that
exceed what VACM can handle.
Values for type otherName(5) are converted to a valid Values for type otherName(5) are converted to a valid
securityName by using only the decoded value portion of the securityName by using only the decoded value portion of the
OthenName sequence. i.e. the OBJECT IDENTIFIER portion of the OtherName sequence. I.E. the OBJECT IDENTIFIER portion of the
OtherName sequence is not included as part of the resulting OtherName sequence is not included as part of the resulting
securityName." securityName."
DEFVAL { any } DEFVAL { any }
::= { tlstmCertToSNEntry 6 } ::= { tlstmCertToSNEntry 5 }
tlstmCertToSNStorageType OBJECT-TYPE tlstmCertToSNStorageType OBJECT-TYPE
SYNTAX StorageType SYNTAX StorageType
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The storage type for this conceptual row. Conceptual rows "The storage type for this conceptual row. Conceptual rows
having the value 'permanent' need not allow write-access to having the value 'permanent' need not allow write-access to
any columnar objects in the row." any columnar objects in the row."
DEFVAL { nonVolatile } DEFVAL { nonVolatile }
::= { tlstmCertToSNEntry 7 } ::= { tlstmCertToSNEntry 6 }
tlstmCertToSNRowStatus OBJECT-TYPE tlstmCertToSNRowStatus OBJECT-TYPE
SYNTAX RowStatus SYNTAX RowStatus
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The status of this conceptual row. This object may be used "The status of this conceptual row. This object may be used
to create or remove rows from this table. to create or remove rows from this table.
To create a row in this table, a manager must set this object To create a row in this table, a manager must set this object
to either createAndGo(4) or createAndWait(5). to either createAndGo(4) or createAndWait(5).
Until instances of all corresponding columns are appropriately Until instances of all corresponding columns are appropriately
configured, the value of the corresponding instance of the configured, the value of the corresponding instance of the
tlstmParamsRowStatus column is 'notReady'. tlstmParamsRowStatus column is 'notReady'.
In particular, a newly created row cannot be made active until In particular, a newly created row cannot be made active until
the corresponding tlstmCertToSNHashType, the corresponding tlstmCertToSNFingerprint,
tlstmCertToSNHashValue, tlstmCertToSNMapType, tlstmCertToSNMapType, tlstmCertToSNSecurityName, and
tlstmCertToSNSecurityName, and tlstmCertToSNSANType columns tlstmCertToSNSANType columns have been set.
have been set.
The following objects may not be modified while the The following objects may not be modified while the
value of this object is active(1): value of this object is active(1):
- tlstmCertToSNHashType
- tlstmCertToSNHashValue - tlstmCertToSNFingerprint
- tlstmCertToSNMapType - tlstmCertToSNMapType
- tlstmCertToSNSecurityName - tlstmCertToSNSecurityName
- tlstmCertToSNSANType - tlstmCertToSNSANType
An attempt to set these objects while the value of An attempt to set these objects while the value of
tlstmParamsRowStatus is active(1) will result in tlstmParamsRowStatus is active(1) will result in
an inconsistentValue error." an inconsistentValue error."
::= { tlstmCertToSNEntry 8 } ::= { tlstmCertToSNEntry 7 }
-- Maps securityNames to certificates for use by the SNMP-TARGET-MIB -- Maps securityNames to certificates for use by the SNMP-TARGET-MIB
tlstmParamsCount OBJECT-TYPE tlstmParamsCount OBJECT-TYPE
SYNTAX Unsigned32 SYNTAX Unsigned32
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A count of the number of entries in the tlstmParamsTable" "A count of the number of entries in the tlstmParamsTable"
::= { tlstmCertificateMapping 4 } ::= { tlstmCertificateMapping 4 }
skipping to change at page 46, line 25 skipping to change at page 46, line 50
snmpTargetParamsTable with an additional (D)TLS client-side snmpTargetParamsTable with an additional (D)TLS client-side
certificate fingerprint identifier to use when establishing certificate fingerprint identifier to use when establishing
new (D)TLS connections." new (D)TLS connections."
::= { tlstmCertificateMapping 6 } ::= { tlstmCertificateMapping 6 }
tlstmParamsEntry OBJECT-TYPE tlstmParamsEntry OBJECT-TYPE
SYNTAX TlstmParamsEntry SYNTAX TlstmParamsEntry
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A conceptual row containing a locally held certificate's hash "A conceptual row containing a fingerprint hash of a locally
type and hash value for a given snmpTargetParamsEntry. The held certificate for a given snmpTargetParamsEntry. The
values in this row should be ignored if the connection that values in this row should be ignored if the connection that
needs to be established, as indicated by the SNMP-TARGET-MIB needs to be established, as indicated by the SNMP-TARGET-MIB
infrastructure, is not a certificate and (D)TLS based infrastructure, is not a certificate and (D)TLS based
connection. The connection SHOULD NOT be established if the connection. The connection SHOULD NOT be established if the
certificate fingerprint stored in this entry does not point to certificate fingerprint stored in this entry does not point to
a valid locally held certificate or if it points to an usable a valid locally held certificate or if it points to an usable
certificate (such as might happen when the certificate's certificate (such as might happen when the certificate's
expiration date has been reached)." expiration date has been reached)."
INDEX { IMPLIED snmpTargetParamsName } INDEX { IMPLIED snmpTargetParamsName }
::= { tlstmParamsTable 1 } ::= { tlstmParamsTable 1 }
TlstmParamsEntry ::= SEQUENCE { TlstmParamsEntry ::= SEQUENCE {
tlstmParamsClientHashType FingerprintType, tlstmParamsClientFingerprint Fingerprint,
tlstmParamsClientHashValue FingerprintValue, tlstmParamsStorageType StorageType,
tlstmParamsStorageType StorageType, tlstmParamsRowStatus RowStatus
tlstmParamsRowStatus RowStatus
} }
tlstmParamsClientHashType OBJECT-TYPE tlstmParamsClientFingerprint OBJECT-TYPE
SYNTAX FingerprintType SYNTAX Fingerprint
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The hash algorithm type for the hash stored in the
tlstmParamsClientHash column to identify a locally-held X.509
certificate that should be used when initiating a (D)TLS
connection as a (D)TLS client."
DEFVAL { tlstmSHA256 }
::= { tlstmParamsEntry 1 }
tlstmParamsClientHashValue OBJECT-TYPE
SYNTAX FingerprintValue
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A cryptographic hash of a X.509 certificate. This object "A cryptographic hash of a X.509 certificate. This object
should store the hash of a locally held X.509 certificate that should store the hash of a locally held X.509 certificate that
should be used when initiating a (D)TLS connection as a (D)TLS should be used when initiating a (D)TLS connection as a (D)TLS
client." client."
::= { tlstmParamsEntry 2 } ::= { tlstmParamsEntry 1 }
tlstmParamsStorageType OBJECT-TYPE tlstmParamsStorageType OBJECT-TYPE
SYNTAX StorageType SYNTAX StorageType
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The storage type for this conceptual row. Conceptual rows "The storage type for this conceptual row. Conceptual rows
having the value 'permanent' need not allow write-access to having the value 'permanent' need not allow write-access to
any columnar objects in the row." any columnar objects in the row."
DEFVAL { nonVolatile } DEFVAL { nonVolatile }
::= { tlstmParamsEntry 3 } ::= { tlstmParamsEntry 2 }
tlstmParamsRowStatus OBJECT-TYPE tlstmParamsRowStatus OBJECT-TYPE
SYNTAX RowStatus SYNTAX RowStatus
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The status of this conceptual row. This object may be used "The status of this conceptual row. This object may be used
to create or remove rows from this table. to create or remove rows from this table.
To create a row in this table, a manager must set this object To create a row in this table, a manager must set this object
to either createAndGo(4) or createAndWait(5). to either createAndGo(4) or createAndWait(5).
Until instances of all corresponding columns are appropriately Until instances of all corresponding columns are appropriately
configured, the value of the corresponding instance of the configured, the value of the corresponding instance of the
tlstmParamsRowStatus column is 'notReady'. tlstmParamsRowStatus column is 'notReady'.
In particular, a newly created row cannot be made active until In particular, a newly created row cannot be made active until
the corresponding tlstmParamsClientHashType and the corresponding tlstmParamsClientFingerprint column has
tlstmParamsClientHashValue columns have been set. been set.
The tlstmParamsClientFingerprint object may not be modified
while the value of this object is active(1).
The following objects may not be modified while the
value of this object is active(1):
- tlstmParamsClientHashType
- tlstmParamsClientHashValue
An attempt to set these objects while the value of An attempt to set these objects while the value of
tlstmParamsRowStatus is active(1) will result in tlstmParamsRowStatus is active(1) will result in
an inconsistentValue error. an inconsistentValue error.
If this row is deleted it has no effect on the corresponding If this row is deleted it has no effect on the corresponding
row in the targetParamsTable. row in the targetParamsTable.
If the corresponding row in the targetParamsTable is deleted If the corresponding row in the targetParamsTable is deleted
then this row must be automatically removed." then this row must be automatically removed."
::= { tlstmParamsEntry 4 } ::= { tlstmParamsEntry 3 }
-- Lists expected certificate fingerprints to be presented by a DTLS -- Lists expected certificate fingerprints to be presented by a DTLS
-- server -- server
tlstmAddrCount OBJECT-TYPE tlstmAddrCount OBJECT-TYPE
SYNTAX Unsigned32 SYNTAX Unsigned32
MAX-ACCESS read-only MAX-ACCESS read-only
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A count of the number of entries in the tlstmAddrTable" "A count of the number of entries in the tlstmAddrTable"
skipping to change at page 49, line 18 skipping to change at page 49, line 26
another certificate validation path algorithm (e.g. RFC5280) another certificate validation path algorithm (e.g. RFC5280)
can be followed to a configured trust anchor. " can be followed to a configured trust anchor. "
::= { tlstmCertificateMapping 9 } ::= { tlstmCertificateMapping 9 }
tlstmAddrEntry OBJECT-TYPE tlstmAddrEntry OBJECT-TYPE
SYNTAX TlstmAddrEntry SYNTAX TlstmAddrEntry
MAX-ACCESS not-accessible MAX-ACCESS not-accessible
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A conceptual row containing a copy of a locally held "A conceptual row containing a copy of a locally held
certificate's hash type and hash value for a given certificate's fingerprint for a given snmpTargetAddrEntry.
snmpTargetAddrEntry. The values in this row should be ignored The values in this row should be ignored if the connection
if the connection that needs to be established, as indicated that needs to be established, as indicated by the
by the SNMP-TARGET-MIB infrastructure, is not a (D)TLS based SNMP-TARGET-MIB infrastructure, is not a (D)TLS based
connection. If an tlstmAddrEntry exists for a given connection. If an tlstmAddrEntry exists for a given
snmpTargetAddrEntry then the presented server certificate MUST snmpTargetAddrEntry then the presented server certificate MUST
match or the connection MUST NOT be established. If a row in match or the connection MUST NOT be established. If a row in
this table does not exist to match a snmpTargetAddrEntry row this table does not exist to match a snmpTargetAddrEntry row
then the connection SHOULD still proceed if some other then the connection SHOULD still proceed if some other
certificate validation path algorithm (e.g. RFC5280) can be certificate validation path algorithm (e.g. RFC5280) can be
followed to a configured trust anchor." followed to a configured trust anchor."
INDEX { IMPLIED snmpTargetAddrName } INDEX { IMPLIED snmpTargetAddrName }
::= { tlstmAddrTable 1 } ::= { tlstmAddrTable 1 }
TlstmAddrEntry ::= SEQUENCE { TlstmAddrEntry ::= SEQUENCE {
tlstmAddrServerHashType FingerprintType, tlstmAddrServerFingerprint Fingerprint,
tlstmAddrServerHashValue FingerprintValue, tlstmAddrStorageType StorageType,
tlstmAddrStorageType StorageType, tlstmAddrRowStatus RowStatus
tlstmAddrRowStatus RowStatus
} }
tlstmAddrServerHashType OBJECT-TYPE tlstmAddrServerFingerprint OBJECT-TYPE
SYNTAX FingerprintType SYNTAX Fingerprint
MAX-ACCESS read-create
STATUS current
DESCRIPTION
"The hash algorithm type for the hash stored in the
tlstmAddrServerHash column to identify a local copy of the
public X.509 certificate presented by the TLS server."
DEFVAL { tlstmSHA256 }
::= { tlstmAddrEntry 1 }
tlstmAddrServerHashValue OBJECT-TYPE
SYNTAX FingerprintValue
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A cryptographic hash of a public X.509 certificate. This "A cryptographic hash of a public X.509 certificate. This
object should store the hash of a local copy of the public object should store the hash of a local copy of the public
X.509 certificate that the remote server should present during X.509 certificate that the remote server should present during
the (D)TLS connection setup. The presented certificate and the (D)TLS connection setup. The presented certificate and
the locally held copy, referred to by this hash value, MUST the locally held copy, referred to by this hash value, MUST
match exactly or the connection MUST NOT be established." match exactly or the connection MUST NOT be established."
::= { tlstmAddrEntry 2 } ::= { tlstmAddrEntry 1 }
tlstmAddrStorageType OBJECT-TYPE tlstmAddrStorageType OBJECT-TYPE
SYNTAX StorageType SYNTAX StorageType
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The storage type for this conceptual row. Conceptual rows "The storage type for this conceptual row. Conceptual rows
having the value 'permanent' need not allow write-access to having the value 'permanent' need not allow write-access to
any columnar objects in the row." any columnar objects in the row."
DEFVAL { nonVolatile } DEFVAL { nonVolatile }
::= { tlstmAddrEntry 3 } ::= { tlstmAddrEntry 2 }
tlstmAddrRowStatus OBJECT-TYPE tlstmAddrRowStatus OBJECT-TYPE
SYNTAX RowStatus SYNTAX RowStatus
MAX-ACCESS read-create MAX-ACCESS read-create
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The status of this conceptual row. This object may be used "The status of this conceptual row. This object may be used
to create or remove rows from this table. to create or remove rows from this table.
To create a row in this table, a manager must To create a row in this table, a manager must
set this object to either createAndGo(4) or set this object to either createAndGo(4) or
createAndWait(5). createAndWait(5).
Until instances of all corresponding columns are Until instances of all corresponding columns are
appropriately configured, the value of the appropriately configured, the value of the
corresponding instance of the tlstmAddrRowStatus corresponding instance of the tlstmAddrRowStatus
column is 'notReady'. column is 'notReady'.
In particular, a newly created row cannot be made active until In particular, a newly created row cannot be made active until
the corresponding tlstmAddrServerHashType, and the corresponding tlstmAddrServerFingerprint column has been
tlstmAddrServerHashValue columns have been set. set.
The following objects may not be modified while the The tlstmAddrServerFingerprint object may not be modified
value of this object is active(1): while the value of this object is active(1).
- tlstmAddrServerHashType
- tlstmAddrServerHashValue
An attempt to set these objects while the value of An attempt to set these objects while the value of
tlstmAddrRowStatus is active(1) will result in tlstmAddrRowStatus is active(1) will result in
an inconsistentValue error. an inconsistentValue error.
If this row is deleted it has no effect on the corresponding If this row is deleted it has no effect on the corresponding
row in the targetAddrTable. row in the targetAddrTable.
If the corresponding row in the targetAddrTable is deleted If the corresponding row in the targetAddrTable is deleted
then this row must be automatically removed." then this row must be automatically removed."
::= { tlstmAddrEntry 4 } ::= { tlstmAddrEntry 3 }
-- ************************************************ -- ************************************************
-- tlstmNotifications - Notifications Information
-- ************************************************
tlstmServerCertNotFound NOTIFICATION-TYPE
STATUS current
DESCRIPTION
"Notification that the server certificate presented by a SNMP
over (D)TLS server could not be found in the tlstmAddrTable."
::= { tlstmNotifications 1 }
tlstmServerAuthFailure NOTIFICATION-TYPE
OBJECTS { tlstmAddrServerFingerprint }
STATUS current
DESCRIPTION
"Notification that the server certificate presented by an SNMP
over (D)TLS server was found, but the connection could not be
established because of a cryptographic validation failure."
::= { tlstmNotifications 2 }
-- ************************************************
-- tlstmCompliances - Conformance Information
-- ************************************************ -- ************************************************
tlstmCompliances OBJECT IDENTIFIER ::= { tlstmConformance 1 } tlstmCompliances OBJECT IDENTIFIER ::= { tlstmConformance 1 }
tlstmGroups OBJECT IDENTIFIER ::= { tlstmConformance 2 } tlstmGroups OBJECT IDENTIFIER ::= { tlstmConformance 2 }
-- ************************************************ -- ************************************************
-- Compliance statements -- Compliance statements
-- ************************************************ -- ************************************************
tlstmCompliance MODULE-COMPLIANCE tlstmCompliance MODULE-COMPLIANCE
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"The compliance statement for SNMP engines that support the "The compliance statement for SNMP engines that support the
TLSTM-MIB" TLSTM-MIB"
MODULE MODULE
MANDATORY-GROUPS { tlstmStatsGroup, MANDATORY-GROUPS { tlstmStatsGroup,
tlstmIncomingGroup, tlstmOutgoingGroup } tlstmIncomingGroup,
tlstmOutgoingGroup,
tlstmNotificationGroup }
::= { tlstmCompliances 1 } ::= { tlstmCompliances 1 }
-- ************************************************ -- ************************************************
-- Units of conformance -- Units of conformance
-- ************************************************ -- ************************************************
tlstmStatsGroup OBJECT-GROUP tlstmStatsGroup OBJECT-GROUP
OBJECTS { OBJECTS {
tlstmSessionOpens, tlstmSessionOpens,
tlstmSessionCloses, tlstmSessionCloses,
tlstmSessionOpenErrors, tlstmSessionOpenErrors,
skipping to change at page 52, line 17 skipping to change at page 52, line 33
DESCRIPTION DESCRIPTION
"A collection of objects for maintaining "A collection of objects for maintaining
statistical information of an SNMP engine which statistical information of an SNMP engine which
implements the SNMP TLS Transport Model." implements the SNMP TLS Transport Model."
::= { tlstmGroups 1 } ::= { tlstmGroups 1 }
tlstmIncomingGroup OBJECT-GROUP tlstmIncomingGroup OBJECT-GROUP
OBJECTS { OBJECTS {
tlstmCertToSNCount, tlstmCertToSNCount,
tlstmCertToSNTableLastChanged, tlstmCertToSNTableLastChanged,
tlstmCertToSNHashType, tlstmCertToSNFingerprint,
tlstmCertToSNHashValue,
tlstmCertToSNMapType, tlstmCertToSNMapType,
tlstmCertToSNSecurityName, tlstmCertToSNSecurityName,
tlstmCertToSNSANType, tlstmCertToSNSANType,
tlstmCertToSNStorageType, tlstmCertToSNStorageType,
tlstmCertToSNRowStatus tlstmCertToSNRowStatus
} }
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A collection of objects for maintaining "A collection of objects for maintaining
incoming connection certificate mappings to incoming connection certificate mappings to
securityNames of an SNMP engine which implements the securityNames of an SNMP engine which implements the
SNMP TLS Transport Model." SNMP TLS Transport Model."
::= { tlstmGroups 2 } ::= { tlstmGroups 2 }
tlstmOutgoingGroup OBJECT-GROUP tlstmOutgoingGroup OBJECT-GROUP
OBJECTS { OBJECTS {
tlstmParamsCount, tlstmParamsCount,
tlstmParamsTableLastChanged, tlstmParamsTableLastChanged,
tlstmParamsClientHashType, tlstmParamsClientFingerprint,
tlstmParamsClientHashValue,
tlstmParamsStorageType, tlstmParamsStorageType,
tlstmParamsRowStatus, tlstmParamsRowStatus,
tlstmAddrCount, tlstmAddrCount,
tlstmAddrTableLastChanged, tlstmAddrTableLastChanged,
tlstmAddrServerHashType, tlstmAddrServerFingerprint,
tlstmAddrServerHashValue,
tlstmAddrStorageType, tlstmAddrStorageType,
tlstmAddrRowStatus tlstmAddrRowStatus
} }
STATUS current STATUS current
DESCRIPTION DESCRIPTION
"A collection of objects for maintaining "A collection of objects for maintaining
outgoing connection certificates to use when opening outgoing connection certificates to use when opening
connections as a result of SNMP-TARGET-MIB settings." connections as a result of SNMP-TARGET-MIB settings."
::= { tlstmGroups 3 } ::= { tlstmGroups 3 }
tlstmNotificationGroup NOTIFICATION-GROUP
NOTIFICATIONS {
tlstmServerCertNotFound,
tlstmServerAuthFailure
}
STATUS current
DESCRIPTION
"Notifications"
::= { tlstmGroups 4 }
END END
8. Operational Considerations 8. Operational Considerations
This section discusses various operational aspects of the solution This section discusses various operational aspects of deploying
TLSTM.
8.1. Sessions 8.1. Sessions
A session is discussed throughout this document as meaning a security A session is discussed throughout this document as meaning a security
association between the (D)TLS client and the (D)TLS server. State association between the (D)TLS client and the (D)TLS server. State
information for the sessions are maintained in each TLSTM and this information for the sessions are maintained in each TLSTM
information is created and destroyed as sessions are opened and implementation and this information is created and destroyed as
closed. Because of the connectionless nature of UDP, a "broken" sessions are opened and closed. A "broken" session (one side up and
session, one side up one side down, could result if one side of a one side down) can result if one side of a session is brought down
session is brought down abruptly (i.e., reboot, power outage, etc.). abruptly (i.e., reboot, power outage, etc.). Whenever possible,
Whenever possible, implementations SHOULD provide graceful session implementations SHOULD provide graceful session termination through
termination through the use of disconnect messages. Implementations the use of disconnect messages. Implementations SHOULD also have a
SHOULD also have a system in place for dealing with "broken" system in place for dealing with "broken" sessions. Implementations
sessions. Implementations SHOULD support the session resumption SHOULD support the session resumption feature of TLS.
feature of TLS.
To simplify session management it is RECOMMENDED that implementations To simplify session management it is RECOMMENDED that implementations
utilize two separate ports, one for Notification sessions and one for use separate ports for Notification sessions and for Command
Command sessions. If this implementation recommendation is followed, sessions. If this implementation recommendation is followed, (D)TLS
(D)TLS clients will always send REQUEST messages and (D)TLS servers clients will always send REQUEST messages and (D)TLS servers will
will always send RESPONSE messages. With this assertion, always send RESPONSE messages. With this assertion, implementations
implementations may be able to simplify "broken" session handling, may be able to simplify "broken" session handling, session
session resumption, and other aspects of session management such as resumption, and other aspects of session management such as
guaranteeing that Request- Response pairs use the same session. guaranteeing that Request- Response pairs use the same session.
Implementations SHOULD limit the lifetime of established sessions Implementations SHOULD limit the lifetime of established sessions
depending on the algorithms used for generation of the master session depending on the algorithms used for generation of the master session
secret, the privacy and integrity algorithms used to protect secret, the privacy and integrity algorithms used to protect
messages, the environment of the session, the amount of data messages, the environment of the session, the amount of data
transferred, and the sensitivity of the data. transferred, and the sensitivity of the data.
8.2. Notification Receiver Credential Selection 8.2. Notification Receiver Credential Selection
When an SNMP engine needs to establish an outgoing session for When an SNMP engine needs to establish an outgoing session for
notifications, the snmpTargetParamsTable includes an entry for the notifications, the snmpTargetParamsTable includes an entry for the
snmpTargetParamsSecurityName of the target. However, the receiving snmpTargetParamsSecurityName of the target. However, the receiving
SNMP engine (Server) does not know which (D)TLS certificate to offer SNMP engine (Server) does not know which (D)TLS certificate to offer
to the Client so that the tmSecurityName identity-authentication will to the Client so that the tmSecurityName identity-authentication will
be successful. The best solution would be to maintain a one-to-one be successful.
mapping between certificates and incoming ports for notification
receivers, although other implementation dependent mechanisms may be One solution is to maintain a one-to-one mapping between certificates
used instead. This can be handled at the Notification Originator by and incoming ports for notification receivers. This can be handled
configuring the snmpTargetAddrTable (snmpTargetAddrTDomain and at the Notification Originator by configuring the snmpTargetAddrTable
snmpTargetAddrTAddress) and then requiring the receiving SNMP engine (snmpTargetAddrTDomain and snmpTargetAddrTAddress) and requiring the
to monitor multiple incoming static ports based on which principals receiving SNMP engine to monitor multiple incoming static ports based
are capable of receiving notifications. Implementations MAY also on which principals are capable of receiving notifications.
choose to designate a single Notification Receiver Principal to
receive all incoming TRAPS and INFORMS. Implementations MAY also choose to designate a single Notification
Receiver Principal to receive all incoming TRAPS and INFORMS or
select an implementation specific method of selecting a server
certificate to present to clients.
8.3. contextEngineID Discovery 8.3. contextEngineID Discovery
Because most Command Responders have contextEngineIDs that are Most Command Responders have contextEngineIDs that are identical to
identical to the USM securityEngineID, the USM provides Command the USM securityEngineID. USM provides a discovery service that
Generators with the ability to discover a default contextEngineID to allows Command Generators to determine a securityEngineID and thus a
use. Because the TLS Transport Model does not make use of a default contextEngineID to use. Because the TLS Transport Model does
discoverable securityEngineID like the USM does, it may be difficult not make use of a securityEngineID, it may be difficult for Command
for Command Generators to discover a suitable default Generators to discover a suitable default contextEngineID.
contextEngineID. Implementations should consider offering another Implementations should consider offering another engineID discovery
engineID discovery mechanism to continue providing Command Generators mechanism to continue providing Command Generators with a suitable
with a contextEngineID discovery mechanism. A recommended discovery contextEngineID mechanism. A recommended discovery solution is
solution is documented in [RFC5343]. documented in [RFC5343].
9. Security Considerations 9. Security Considerations
This document describes a transport model that permits SNMP to This document describes a transport model that permits SNMP to
utilize (D)TLS security services. The security threats and how the utilize (D)TLS security services. The security threats and how the
(D)TLS transport model mitigates these threats are covered in detail (D)TLS transport model mitigates these threats are covered in detail
throughout this document. Security considerations for DTLS are throughout this document. Security considerations for DTLS are
covered in [RFC4347] and security considerations for TLS are covered in [RFC4347] and security considerations for TLS are
described in Section 11 and Appendices D, E, and F of TLS 1.2 described in Section 11 and Appendices D, E, and F of TLS 1.2
[RFC5246]. DTLS adds to the security considerations of TLS only [RFC5246]. DTLS adds to the security considerations of TLS only
because it is more vulnerable to denial of service attacks. A random because it is more vulnerable to denial of service attacks. A random
cookie exchange was added to the handshake to prevent anonymous cookie exchange was added to the handshake to prevent anonymous
denial of service attacks. RFC 4347 recommends that the cookie denial of service attacks. RFC 4347 recommends that the cookie
exchange is utilized for all handshakes and therefore it is exchange is utilized for all handshakes and therefore this
RECOMMENDED that implementers also support this cookie exchange. specification also RECOMMENDEDs that implementers also support this
cookie exchange.
9.1. Certificates, Authentication, and Authorization 9.1. Certificates, Authentication, and Authorization
Implementations are responsible for providing a security certificate Implementations are responsible for providing a security certificate
configuration installation . Implementations SHOULD support installation and configuration mechanism. Implementations SHOULD
certificate revocation lists and expiration of certificates or other support certificate revocation lists.
access control mechanisms.
(D)TLS provides for both authentication of the identity of the (D)TLS (D)TLS provides for authentication of the identity of both the (D)TLS
server and authentication of the identity of the (D)TLS client. server and the (D)TLS client. Access to MIB objects for the
Access to MIB objects for the authenticated principal MUST be authenticated principal MUST be enforced by an access control
enforced by an access control subsystem (e.g. the VACM). subsystem (e.g. the VACM).
Authentication of the Command Generator principal's identity is Authentication of the Command Generator principal's identity is
important for use with the SNMP access control subsystem to ensure important for use with the SNMP access control subsystem to ensure
that only authorized principals have access to potentially sensitive that only authorized principals have access to potentially sensitive
data. The authenticated identity of the Command Generator data. The authenticated identity of the Command Generator
principal's certificate is mapped to an SNMP model-independent principal's certificate is mapped to an SNMP model-independent
securityName for use with SNMP access control. securityName for use with SNMP access control.
Furthermore, the (D)TLS handshake only provides assurance that the The (D)TLS handshake only provides assurance that the certificate of
certificate of the authenticated identity has been signed by an the authenticated identity has been signed by an configured accepted
configured accepted Certificate Authority. (D)TLS has no way to Certificate Authority. (D)TLS has no way to further authorize or
further authorize or reject access based on the authenticated reject access based on the authenticated identity. An Access Control
identity. An Access Control Model (such as the VACM) provides access Model (such as the VACM) provides access control and authorization of
control and authorization of a Command Generator's requests to a a Command Generator's requests to a Command Responder and a
Command Responder and a Notification Responder's authorization to Notification Responder's authorization to receive Notifications from
receive Notifications from a Notification Originator. However to a Notification Originator. However to avoid man-in-the-middle
avoid man-in-the-middle attacks both ends of the (D)TLS based attacks both ends of the (D)TLS based connection MUST check the
connection MUST check the certificate presented by the other side certificate presented by the other side against what was expected.
against what was expected. For example, Command Generators must For example, Command Generators must check that the Command Responder
check that the Command Responder presented and authenticated itself presented and authenticated itself with a X.509 certificate that was
with a X.509 certificate that was expected. Not doing so would allow expected. Not doing so would allow an impostor, at a minimum, to
an impostor, at a minimum, to present false data, receive sensitive present false data, receive sensitive information and/or provide a
information and/or provide a false-positive belief that configuration false belief that configuration was actually received and acted upon.
was actually received and acted upon. Authenticating and verifying Authenticating and verifying the identity of the (D)TLS server and
the identity of the (D)TLS server and the (D)TLS client for all the (D)TLS client for all operations ensures the authenticity of the
operations ensures the authenticity of the SNMP engine that provides SNMP engine that provides MIB data.
MIB data.
The instructions found in the DESCRIPTION clause of the The instructions found in the DESCRIPTION clause of the
tlstmCertToSNTable object must be followed exactly. Specifically, it tlstmCertToSNTable object must be followed exactly. It is also
is important that if a row matching a certificate or a certificate's important that the rows of the table be searched in prioritized order
issuer is found but the translation to a securityName using the row starting with the row containing the lowest numbered tlstmCertToSNID
fails that the lookup process stops and no further rows are value.
consulted. It is also important that the rows of the table be search
in order starting with the row containing the lowest numbered
tlstmCertToSNID value.
9.2. Use with SNMPv1/SNMPv2c Messages 9.2. Use with SNMPv1/SNMPv2c Messages
The SNMPv1 and SNMPv2c message processing described in RFC3484 (BCP The SNMPv1 and SNMPv2c message processing described in RFC3484 (BCP
74) [RFC3584] always selects the SNMPv1(1) Security Model for an 74) [RFC3584] always selects the SNMPv1(1) Security Model for an
SNMPv1 message, or the SNMPv2c(2) Security Model for an SNMPv2c SNMPv1 message, or the SNMPv2c(2) Security Model for an SNMPv2c
message. When running SNMPv1/SNMPv2c over a secure transport like message. When running SNMPv1/SNMPv2c over a secure transport like
the TLS Transport Model, the securityName and securityLevel used for the TLS Transport Model, the securityName and securityLevel used for
access control decisions are then derived from the community string, access control decisions are then derived from the community string,
not the authenticated identity and securityLevel provided by the TLS not the authenticated identity and securityLevel provided by the TLS
skipping to change at page 57, line 32 skipping to change at page 58, line 7
instance of this MIB module is properly configured to give access to instance of this MIB module is properly configured to give access to
the objects only to those principals (users) that have legitimate the objects only to those principals (users) that have legitimate
rights to indeed GET or SET (change/create/delete) them. rights to indeed GET or SET (change/create/delete) them.
10. IANA Considerations 10. IANA Considerations
IANA is requested to assign: IANA is requested to assign:
1. a TCP port number in the range 1..1023 in the 1. a TCP port number in the range 1..1023 in the
http://www.iana.org/assignments/port-numbers registry which will http://www.iana.org/assignments/port-numbers registry which will
be the default port for SNMP command messages over a TLS be the default port for receipt of SNMP command messages over a
Transport Model as defined in this document, TLS Transport Model as defined in this document,
2. a TCP port number in the range 1..1023 in the 2. a TCP port number in the range 1..1023 in the
http://www.iana.org/assignments/port-numbers registry which will http://www.iana.org/assignments/port-numbers registry which will
be the default port for SNMP notification messages over a TLS be the default port for receipt of SNMP notification messages
Transport Model as defined in this document, over a TLS Transport Model as defined in this document,
3. a UDP port number in the range 1..1023 in the 3. a UDP port number in the range 1..1023 in the
http://www.iana.org/assignments/port-numbers registry which will http://www.iana.org/assignments/port-numbers registry which will
be the default port for SNMP command messages over a DTLS/UDP be the default port for receipt of SNMP command messages over a
connection as defined in this document, DTLS/UDP connection as defined in this document,
4. a UDP port number in the range 1..1023 in the 4. a UDP port number in the range 1..1023 in the
http://www.iana.org/assignments/port-numbers registry which will http://www.iana.org/assignments/port-numbers registry which will
be the default port for SNMP notification messages over a DTLS/ be the default port for receipt of SNMP notification messages
UDP connection as defined in this document, over a DTLS/UDP connection as defined in this document,
5. a SCTP port number in the range 1..1023 in the 5. a SCTP port number in the range 1..1023 in the
http://www.iana.org/assignments/port-numbers registry which will http://www.iana.org/assignments/port-numbers registry which will
be the default port for SNMP command messages over a DTLS/SCTP be the default port for receipt of SNMP command messages over a
connection as defined in this document, DTLS/SCTP connection as defined in this document,
6. a SCTP port number in the range 1..1023 in the 6. a SCTP port number in the range 1..1023 in the
http://www.iana.org/assignments/port-numbers registry which will http://www.iana.org/assignments/port-numbers registry which will
be the default port for SNMP notification messages over a DTLS/ be the default port for receipt of SNMP notification messages
SCTP connection as defined in this document, over a DTLS/SCTP connection as defined in this document,
7. an SMI number under snmpDomains for the snmpTLSDomain object 7. an SMI number under snmpDomains for the snmpTLSDomain object
identifier, identifier,
8. an SMI number under snmpDomains for the snmpDTLSUDPDomain object 8. an SMI number under snmpDomains for the snmpDTLSUDPDomain object
identifier, identifier,
9. an SMI number under snmpDomains for the snmpDTLSSCTPDomain 9. an SMI number under snmpDomains for the snmpDTLSSCTPDomain
object identifier, object identifier,
skipping to change at page 58, line 36 skipping to change at page 59, line 8
11. "tls" as the corresponding prefix for the snmpTLSDomain in the 11. "tls" as the corresponding prefix for the snmpTLSDomain in the
SNMP Transport Model registry, SNMP Transport Model registry,
12. "dudp" as the corresponding prefix for the snmpDTLSUDPDomain in 12. "dudp" as the corresponding prefix for the snmpDTLSUDPDomain in
the SNMP Transport Model registry, the SNMP Transport Model registry,
13. "dsct" as the corresponding prefix for the snmpDTLSSCTPDomain in 13. "dsct" as the corresponding prefix for the snmpDTLSSCTPDomain in
the SNMP Transport Model registry; the SNMP Transport Model registry;
14. Editor's note: this section should be replaced with appropriate If possible, IANA is requested to use matching port numbers for all
descriptive assignment text after IANA assignments are made and assignments for SNMP Commands being sent over TLS, DTLS/UDP, DTLS/
prior to publication. SCTP.
If possible, IANA is requested to use matching port numbers for all
assignments for SNMP Notifications being sent over TLS, DTLS/UDP,
DTLS/SCTP.
Editor's note: this section should be replaced with appropriate
descriptive assignment text after IANA assignments are made and prior
to publication.
11. Acknowledgements 11. Acknowledgements
This document closely follows and copies the Secure Shell Transport This document closely follows and copies the Secure Shell Transport
Model for SNMP defined by David Harrington and Joseph Salowey in Model for SNMP defined by David Harrington and Joseph Salowey in
[I-D.ietf-isms-secshell]. [RFC5292].
This document was reviewed by the following people who helped provide This document was reviewed by the following people who helped provide
useful comments: David Harrington, Alan Luchuk, Ray Purvis. useful comments (in alphabetical order): Andy Donati, Pasi Eronen,
David Harrington, Jeffrey Hutzelman, Alan Luchuk, Randy Presuhn, Ray
Purvis, Joseph Salowey, Jurgen Schonwalder, Dave Shield.
This work was supported in part by the United States Department of This work was supported in part by the United States Department of
Defense. Large portions of this document are based on work by Defense. Large portions of this document are based on work by
General Dynamics C4 Systems and the following individuals: Brian General Dynamics C4 Systems and the following individuals: Brian
Baril, Kim Bryant, Dana Deluca, Dan Hanson, Tim Huemiller, John Baril, Kim Bryant, Dana Deluca, Dan Hanson, Tim Huemiller, John
Holzhauer, Colin Hoogeboom, Dave Kornbau, Chris Knaian, Dan Knaul, Holzhauer, Colin Hoogeboom, Dave Kornbau, Chris Knaian, Dan Knaul,
Charles Limoges, Steve Moccaldi, Gerardo Orlando, and Brandon Yip. Charles Limoges, Steve Moccaldi, Gerardo Orlando, and Brandon Yip.
12. References 12. References
skipping to change at page 60, line 18 skipping to change at page 60, line 48
Security", RFC 4347, April 2006. Security", RFC 4347, April 2006.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008. (TLS) Protocol Version 1.2", RFC 5246, August 2008.
[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, May 2008. (CRL) Profile", RFC 5280, May 2008.
[I-D.ietf-isms-transport-security-model] [RFC5590] Harrington, D. and J. Schoenwaelder, "Transport Subsystem
Harington, D., "Transport Security Model for SNMP". for the Simple Network Management Protocol (SNMP)",
RFC 5590, June 2009.
[I-D.ietf-isms-tmsm] [RFC5591] Harrington, D. and W. Hardaker, "Transport Security Model
Harington, D. and J. Schoenwaelder, "Transport Subsystem for the Simple Network Management Protocol (SNMP)",
for the Simple Network Management Protocol (SNMP)". RFC 5591, June 2009.
12.2. Informative References 12.2. Informative References
[RFC2522] Karn, P. and W. Simpson, "Photuris: Session-Key Management [RFC2522] Karn, P. and W. Simpson, "Photuris: Session-Key Management
Protocol", RFC 2522, March 1999. Protocol", RFC 2522, March 1999.
[RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, [RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart,
"Introduction and Applicability Statements for Internet- "Introduction and Applicability Statements for Internet-
Standard Management Framework", RFC 3410, December 2002. Standard Management Framework", RFC 3410, December 2002.
[RFC4302] Kent, S., "IP Authentication Header", RFC 4302,
December 2005.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, December 2005.
[RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", [RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol",
RFC 4306, December 2005. RFC 4306, December 2005.
[I-D.ietf-isms-secshell] [RFC5292] Chen, E. and S. Sangli, "Address-Prefix-Based Outbound
Harington, D. and J. Salowey, "Secure Shell Transport Route Filter for BGP-4", RFC 5292, August 2008.
Model for SNMP".
[RFC5343] Schoenwaelder, J., "Simple Network Management Protocol [RFC5343] Schoenwaelder, J., "Simple Network Management Protocol
(SNMP) Context EngineID Discovery". (SNMP) Context EngineID Discovery", RFC 5343,
September 2008.
[I-D.saintandre-tls-server-id-check] [I-D.saintandre-tls-server-id-check]
Saint-Andre, P., Zeilenga, K., Hodges, J., and B. Morgan, Saint-Andre, P., Zeilenga, K., Hodges, J., and B. Morgan,
"Best Practices for Checking of Server Identities in the "Best Practices for Checking of Server Identities in the
Context of Transport Layer Security (TLS)". Context of Transport Layer Security (TLS)".
[AES] National Institute of Standards, "Specification for the [AES] National Institute of Standards, "Specification for the
Advanced Encryption Standard (AES)". Advanced Encryption Standard (AES)".
[DES] National Institute of Standards, "American National [DES] National Institute of Standards, "American National
skipping to change at page 61, line 41 skipping to change at page 62, line 22
A.1. The (D)TLS Record Protocol A.1. The (D)TLS Record Protocol
At the lowest layer, layered on top of the transport control protocol At the lowest layer, layered on top of the transport control protocol
or a datagram transport protocol (e.g. UDP or SCTP) is the (D)TLS or a datagram transport protocol (e.g. UDP or SCTP) is the (D)TLS
Record Protocol. Record Protocol.
The (D)TLS Record Protocol provides security that has three basic The (D)TLS Record Protocol provides security that has three basic
properties: properties:
o The session can be confidential. Symmetric cryptography is used o The session can be confidential. Symmetric cryptography is used
for data encryption (e.g., AES [AES], DES [DES] etc.). The keys for data encryption (e.g., [AES], [DES] etc.). The keys for this
for this symmetric encryption are generated uniquely for each symmetric encryption are generated uniquely for each session and
session and are based on a secret negotiated by another protocol are based on a secret negotiated by another protocol (such as the
(such as the (D)TLS Handshake Protocol). The Record Protocol can (D)TLS Handshake Protocol). The Record Protocol can also be used
also be used without encryption. without encryption.
o Messages can have data integrity. Message transport includes a o Messages can have data integrity. Message transport includes a
message integrity check using a keyed MAC. Secure hash functions message integrity check using a keyed MAC. Secure hash functions
(e.g., SHA, MD5, etc.) are used for MAC computations. The Record (e.g., SHA, MD5, etc.) are used for MAC computations. The Record
Protocol can operate without a MAC, but is generally only used in Protocol can operate without a MAC, but is generally only used in
this mode while another protocol is using the Record Protocol as a this mode while another protocol is using the Record Protocol as a
transport for negotiating security parameters. transport for negotiating security parameters.
o Messages are protected against replay. (D)TLS uses explicit o Messages are protected against replay. (D)TLS uses explicit
sequence numbers and integrity checks. DTLS uses a sliding window sequence numbers and integrity checks. DTLS uses a sliding window
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A.2. The (D)TLS Handshake Protocol A.2. The (D)TLS Handshake Protocol
The (D)TLS Record Protocol is used for encapsulation of various The (D)TLS Record Protocol is used for encapsulation of various
higher-level protocols. One such encapsulated protocol, the (D)TLS higher-level protocols. One such encapsulated protocol, the (D)TLS
Handshake Protocol, allows the server and client to authenticate each Handshake Protocol, allows the server and client to authenticate each
other and to negotiate an integrity algorithm, an encryption other and to negotiate an integrity algorithm, an encryption
algorithm and cryptographic keys before the application protocol algorithm and cryptographic keys before the application protocol
transmits or receives its first octet of data. Only the (D)TLS transmits or receives its first octet of data. Only the (D)TLS
client can initiate the handshake protocol. The (D)TLS Handshake client can initiate the handshake protocol. The (D)TLS Handshake
Protocol provides security that has three basic properties: Protocol provides security that has four basic properties:
o The peer's identity can be authenticated using asymmetric (public o The peer's identity can be authenticated using asymmetric (public
key) cryptography (e.g., RSA [RSA], DSS [DSS], etc.). This key) cryptography (e.g., RSA [RSA], DSS [DSS], etc.). This
authentication can be made optional, but is generally required by authentication can be made optional, but is generally required by
at least one of the peers. at least one of the peers.
(D)TLS supports three authentication modes: authentication of both (D)TLS supports three authentication modes: authentication of both
the server and the client, server authentication with an the server and the client, server authentication with an
unauthenticated client, and total anonymity. For authentication unauthenticated client, and total anonymity. For authentication
of both entities, each entity provides a valid certificate chain of both entities, each entity provides a valid certificate chain
leading to an acceptable certificate authority. Each entity is leading to an acceptable certificate authority. Each entity is
responsible for verifying that the other's certificate is valid responsible for verifying that the other's certificate is valid
and has not expired or been revoked. See and has not expired or been revoked. See
[I-D.saintandre-tls-server-id-check] for further details on [I-D.saintandre-tls-server-id-check] for further details on
standardized processing when checking Server certificate standardized processing when checking server certificate
identities. identities.
o The negotiation of a shared secret is secure: the negotiated o The negotiation of a shared secret is secure: the negotiated
secret is unavailable to eavesdroppers, and for any authenticated secret is unavailable to eavesdroppers, and for any authenticated
handshake the secret cannot be obtained, even by an attacker who handshake the secret cannot be obtained, even by an attacker who
can place himself in the middle of the session. can place himself in the middle of the session.
o The negotiation is not vulnerable to malicious modification: it is o The negotiation is not vulnerable to malicious modification: it is
infeasible for an attacker to modify negotiation communication infeasible for an attacker to modify negotiation communication
without being detected by the parties to the communication. without being detected by the parties to the communication.
skipping to change at page 63, line 36 skipping to change at page 64, line 15
unsecured storage in certificate-using systems. unsecured storage in certificate-using systems.
ITU-T X.509 (formerly CCITT X.509) or ISO/IEC/ITU 9594-8, which was ITU-T X.509 (formerly CCITT X.509) or ISO/IEC/ITU 9594-8, which was
first published in 1988 as part of the X.500 Directory first published in 1988 as part of the X.500 Directory
recommendations, defines a standard certificate format [x509] which recommendations, defines a standard certificate format [x509] which
is a certificate which binds a subject (principal) to a public key is a certificate which binds a subject (principal) to a public key
value. This was later further documented in [RFC5280]. value. This was later further documented in [RFC5280].
A X.509 certificate is a sequence of three required fields: A X.509 certificate is a sequence of three required fields:
tbsCertificate: The field contains the names of the subject and tbsCertificate: The tbsCertificate field contains the names of the
issuer, a public key associated with the subject, a validity subject and issuer, a public key associated with the subject, a
period, and other associated information. This field may also validity period, and other associated information. This field may
contain extension components. also contain extension components.
signatureAlgorithm: The signatureAlgorithm field contains the signatureAlgorithm: The signatureAlgorithm field contains the
identifier for the cryptographic algorithm used by the certificate identifier for the cryptographic algorithm used by the certificate
authority (CA) to sign this certificate. authority (CA) to sign this certificate.
signatureValue: The signatureValue field contains a digital signatureValue: The signatureValue field contains a digital
signature computed upon the ASN.1 DER encoded tbsCertificate signature computed by the CA upon the ASN.1 DER encoded
field. The ASN.1 DER encoded tbsCertificate is used as the input tbsCertificate field. The ASN.1 DER encoded tbsCertificate is
to the signature function. This signature value is then ASN.1 DER used as the input to the signature function. This signature value
encoded as a BIT STRING and included in the Certificate's is then ASN.1 DER encoded as a BIT STRING and included in the
signature field. By generating this signature, a CA certifies the Certificate's signature field. By generating this signature, the
validity of the information in the tbsCertificate field. In CA certifies the validity of the information in the tbsCertificate
particular, the CA certifies the binding between the public key field. In particular, the CA certifies the binding between the
material and the subject of the certificate. public key material and the subject of the certificate.
The basic X.509 authentication procedure is as follows: A system is The basic X.509 authentication procedure is as follows: A system is
initialized with a number of root certificates that contain the initialized with a number of root certificates that contain the
public keys of a number of trusted CAs. When a system receives a public keys of a number of trusted CAs. When a system receives a
X.509 certificate, signed by one of those CAs, the certificate has to X.509 certificate, signed by one of those CAs, the certificate has to
be verified. It first checks the signatureValue field by using the be verified. It first checks the signatureValue field by using the
public key of the corresponding trusted CA. Then it compares the public key of the corresponding trusted CA. Then it compares the
decrypted information with a digest of the tbsCertificate field. If decrypted information with a digest of the tbsCertificate field. If
they match, then the subject in the tbsCertificate field is they match, then the subject in the tbsCertificate field is
authenticated. authenticated.
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The isAccessAllowed() ASI requires configuration to exist in the The isAccessAllowed() ASI requires configuration to exist in the
following SNMP-VIEW-BASED-ACM-MIB tables: following SNMP-VIEW-BASED-ACM-MIB tables:
vacmSecurityToGroupTable vacmSecurityToGroupTable
vacmAccessTable vacmAccessTable
vacmViewTreeFamilyTable vacmViewTreeFamilyTable
The only table that needs to be discussed as particularly different The only table that needs to be discussed as particularly different
here is the vacmSecurityToGroupTable. This table is indexed by both here is the vacmSecurityToGroupTable. This table is indexed by both
the SNMPv3 security model and the security name. The security model, the SNMPv3 security model and the security name. The security model,
when TLSTM is in use, should be set to the value of XXX corresponding when TLSTM is in use, should be set to the value of 4, corresponding
to the TSM [I-D.ietf-isms-transport-security-model]. An example to the TSM [RFC5591]. An example vacmSecurityToGroupTable row might
vacmSecurityToGroupTable row might be filled out as follows (using a be filled out as follows (using a single SNMP SET request):
single SNMP SET request):
Note to RFC editor: replace XXX in the previous paragraph above with
the actual IANA-assigned number for the TSM security model and remove
this note.
vacmSecurityModel = XXX (TSM) vacmSecurityModel = 4 (TSM)
vacmSecurityName = "blueberry" vacmSecurityName = "blueberry"
vacmGroupaName = "administrators" vacmGroupName = "administrators"
vacmSecurityToGroupStorageType = 3 (nonVolatile) vacmSecurityToGroupStorageType = 3 (nonVolatile)
vacmSecurityToGroupStatus = 4 (createAndGo) vacmSecurityToGroupStatus = 4 (createAndGo)
Note to RFC editor: replace XXX in the vacmSecurityModel line above
with the actual IANA-assigned number for the TSM security model and
remove this note.
This example will assume that the "administrators" group has been This example will assume that the "administrators" group has been
given proper permissions via rows in the vacmAccessTable and given proper permissions via rows in the vacmAccessTable and
vacmViewTreeFamilyTable. vacmViewTreeFamilyTable.
Depending on whether this VACM configuration is for a Command Depending on whether this VACM configuration is for a Command
Responder or a Command Generator the security name "blueberry" will Responder or a Command Generator the security name "blueberry" will
come from a few different locations. come from a few different locations.
C.1. Configuring the Notification Generator
For Notification Generator's performing authorization checks, the For Notification Generator's performing authorization checks, the
server's certificate must be verified against the expected server's certificate must be verified against the expected
certificate before proceeding to send the notification. The certificate before proceeding to send the notification. The expected
securityName be set by the SNMP-TARGET-MIB's certificate from the server may be listed in the tlstmAddrTable or
snmpTargetParamsSecurityName column or other configuration mechanism may be determined through other X.509 path validation mechanisms.
and the certificate to use would be taken from the appropriate entry The securityName to use for VACM authorization checks is set by the
in the tlstmParamsTable. The tlstmParamsTable augments the SNMP- SNMP-TARGET-MIB's snmpTargetParamsSecurityName column.
TARGET-MIB's snmpTargetParamsTable with client-side certificate
information. The certificate that the notification generator should present to the
server is taken from the tlstmParamsClientFingerprint column from the
appropriate entry in the tlstmParamsTable table.
C.2. Configuring the Command Responder
For Command Responder applications, the vacmSecurityName "blueberry" For Command Responder applications, the vacmSecurityName "blueberry"
value is a value that needs to come from an incoming (D)TLS session. value is a value that needs derive from an incoming (D)TLS session.
The mapping from a recevied (D)TLS client certificate to a The mapping from a recevied (D)TLS client certificate to a
securityName is done with the tlstmCertToSNTable. The certificates securityName is done with the tlstmCertToSNTable. The certificates
must be loaded into the device so that a tlstmCertToSNEntry may refer must be loaded into the device so that a tlstmCertToSNEntry may refer
to it. As an example, consider the following entry which will to it. As an example, consider the following entry which will
provide a mapping from a X.509's hash fingerprint directly to the provide a mapping from a client's public X.509's hash fingerprint
"blueberry" securityName: directly to the "blueberry" securityName:
tlstmCertToSNID = 1 (chosen by ordering preference) tlstmCertToSNID = 1 (chosen by ordering preference)
tlstmCertToSNHashType = tlstmSHA256 tlstmCertToSNFingerprint = HASH (appropriate fingerprint)
tlstmCertToSNHashValue = (appropriate sha256 fingerprint) tlstmCertToSNMapType = 1 (specified)
tlstmCertToSNMapType = specified(1)
tlstmCertToSNSecurityName = "blueberry" tlstmCertToSNSecurityName = "blueberry"
tlstmCertToSNStorageType = 3 (nonVolatile) tlstmCertToSNStorageType = 3 (nonVolatile)
tlstmCertToSNRowStatus = 4 (createAndGo) tlstmCertToSNRowStatus = 4 (createAndGo)
The above is an example of how to map a particular certificate to a The above is an example of how to map a particular certificate to a
particular securityName. It is recommended that users make use of particular securityName. It is recommended, however, that users make
direct subjectAltName or CommonName mappings where possible since it use of direct subjectAltName or CommonName mappings where possible as
will provide a more scalable approach to certificate management. it provides a more scalable approach to certificate management. This
This entry provides an example of using a subjectAltName mapping: entry provides an example of using a subjectAltName mapping:
tlstmCertToSNID = 1 (chosen by ordering preference) tlstmCertToSNID = 1 (chosen by ordering preference)
tlstmCertToSNHashType = tlstmSHA256 tlstmCertToSNFingerprint = HASH (appropriate fingerprint)
tlstmCertToSNHashValue = (appropriate sha256 fingerprint) tlstmCertToSNMapType = 2 (bySubjectAltName)
tlstmCertToSNMapType = bySubjectAltName(2) tlstmCertToSNSANType = 1 (any)
tlstmCertToSNSANType = 1 (any) tlstmCertToSNStorageType = 3 (nonVolatile)
tlstmCertToSNStorageType = 3 (nonVolatile) tlstmCertToSNRowStatus = 4 (createAndGo)
tlstmCertToSNRowStatus = 4 (createAndGo)
The above entry indicates the subjectAltName field for certificates The above entry indicates the subjectAltName field for certificates
created by an Issuing certificate with a corresponding hash type and created by an Issuing certificate with a corresponding fingerprint
value will be trusted to always produce common names that are will be trusted to always produce common names that are directly 1 to
directly 1 to 1 mappable into SNMPv3 securityNames. This type of 1 mappable into SNMPv3 securityNames. This type of configuration
configuration should only be used when the certificate authorities should only be used when the certificate authorities naming
naming conventions are carefully controlled. conventions are carefully controlled.
For the example, if the incoming (D)TLS client provided certificate In the example, if the incoming (D)TLS client provided certificate
contained a subjectAltName where the first listed subjectAltName in contained a subjectAltName where the first listed subjectAltName in
the extension is the rfc822Name of "blueberry" and the certificate the extension is the rfc822Name of "blueberry", the certificate was
was signed by a certificate matching the tlstmCertToSNHashType and signed by a certificate matching the tlstmCertToSNFingerprint value
tlstmCertToSNHashValue values above and the CA's certificate was and the CA's certificate was properly installed on the device then
properly installed on the device then the string "blueberry" would be the string "blueberry" would be used as the securityName for the
used as the securityName for the session. session.
Author's Address Author's Address
Wes Hardaker Wes Hardaker
Sparta, Inc. Sparta, Inc.
P.O. Box 382 P.O. Box 382
Davis, CA 95617 Davis, CA 95617
US USA
Phone: +1 530 792 1913 Phone: +1 530 792 1913
Email: ietf@hardakers.net Email: ietf@hardakers.net
 End of changes. 225 change blocks. 
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