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Summary: 6 errors (**), 0 flaws (~~), 8 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 ISMS W. Hardaker 3 Internet-Draft Sparta, Inc. 4 Intended status: Standards Track May 7, 2010 5 Expires: November 8, 2010 7 Transport Layer Security (TLS) Transport Model for the Simple Network 8 Management Protocol (SNMP) 9 draft-ietf-isms-dtls-tm-13.txt 11 Abstract 13 This document describes a Transport Model for the Simple Network 14 Management Protocol (SNMP), that uses either the Transport Layer 15 Security protocol or the Datagram Transport Layer Security (DTLS) 16 protocol. The TLS and DTLS protocols provide authentication and 17 privacy services for SNMP applications. This document describes how 18 the TLS Transport Model (TLSTM) implements the needed features of a 19 SNMP Transport Subsystem to make this protection possible in an 20 interoperable way. 22 This transport model is designed to meet the security and operational 23 needs of network administrators. It supports sending of SNMP 24 messages over TLS/TCP and DTLS/UDP. The TLS mode can make use of 25 TCP's improved support for larger packet sizes and the DTLS mode 26 provides potentially superior operation in environments where a 27 connectionless (e.g. UDP) transport is preferred. Both TLS and DTLS 28 integrate well into existing public keying infrastructures. 30 This document also defines a portion of the Management Information 31 Base (MIB) for use with network management protocols. In particular 32 it defines objects for managing the TLS Transport Model for SNMP. 34 Status of this Memo 36 This Internet-Draft is submitted to IETF in full conformance with the 37 provisions of BCP 78 and BCP 79. 39 Internet-Drafts are working documents of the Internet Engineering 40 Task Force (IETF), its areas, and its working groups. Note that 41 other groups may also distribute working documents as Internet- 42 Drafts. 44 Internet-Drafts are draft documents valid for a maximum of six months 45 and may be updated, replaced, or obsoleted by other documents at any 46 time. It is inappropriate to use Internet-Drafts as reference 47 material or to cite them other than as "work in progress." 48 The list of current Internet-Drafts can be accessed at 49 http://www.ietf.org/ietf/1id-abstracts.txt. 51 The list of Internet-Draft Shadow Directories can be accessed at 52 http://www.ietf.org/shadow.html. 54 This Internet-Draft will expire on November 8, 2010. 56 Copyright Notice 58 Copyright (c) 2010 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (http://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with respect 66 to this document. Code Components extracted from this document must 67 include Simplified BSD License text as described in Section 4.e of 68 the Trust Legal Provisions and are provided without warranty as 69 described in the BSD License. 71 This document may contain material from IETF Documents or IETF 72 Contributions published or made publicly available before November 73 10, 2008. The person(s) controlling the copyright in some of this 74 material may not have granted the IETF Trust the right to allow 75 modifications of such material outside the IETF Standards Process. 76 Without obtaining an adequate license from the person(s) controlling 77 the copyright in such materials, this document may not be modified 78 outside the IETF Standards Process, and derivative works of it may 79 not be created outside the IETF Standards Process, except to format 80 it for publication as an RFC or to translate it into languages other 81 than English. 83 Table of Contents 85 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 86 1.1. Conventions . . . . . . . . . . . . . . . . . . . . . . . 8 87 2. The Transport Layer Security Protocol . . . . . . . . . . . . 9 88 3. How the TLSTM fits into the Transport Subsystem . . . . . . . 9 89 3.1. Security Capabilities of this Model . . . . . . . . . . . 11 90 3.1.1. Threats . . . . . . . . . . . . . . . . . . . . . . . 11 91 3.1.2. Message Protection . . . . . . . . . . . . . . . . . . 12 92 3.1.3. (D)TLS Connections . . . . . . . . . . . . . . . . . . 13 93 3.2. Security Parameter Passing . . . . . . . . . . . . . . . . 14 94 3.3. Notifications and Proxy . . . . . . . . . . . . . . . . . 14 95 4. Elements of the Model . . . . . . . . . . . . . . . . . . . . 15 96 4.1. X.509 Certificates . . . . . . . . . . . . . . . . . . . . 15 97 4.1.1. Provisioning for the Certificate . . . . . . . . . . . 15 98 4.2. (D)TLS Usage . . . . . . . . . . . . . . . . . . . . . . . 17 99 4.3. SNMP Services . . . . . . . . . . . . . . . . . . . . . . 17 100 4.3.1. SNMP Services for an Outgoing Message . . . . . . . . 18 101 4.3.2. SNMP Services for an Incoming Message . . . . . . . . 19 102 4.4. Cached Information and References . . . . . . . . . . . . 19 103 4.4.1. TLS Transport Model Cached Information . . . . . . . . 20 104 4.4.1.1. tmSecurityName . . . . . . . . . . . . . . . . . . 20 105 4.4.1.2. tmSessionID . . . . . . . . . . . . . . . . . . . 20 106 4.4.1.3. Session State . . . . . . . . . . . . . . . . . . 21 107 5. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 21 108 5.1. Procedures for an Incoming Message . . . . . . . . . . . . 21 109 5.1.1. DTLS over UDP Processing for Incoming Messages . . . . 22 110 5.1.2. Transport Processing for Incoming SNMP Messages . . . 23 111 5.2. Procedures for an Outgoing SNMP Message . . . . . . . . . 24 112 5.3. Establishing or Accepting a Session . . . . . . . . . . . 26 113 5.3.1. Establishing a Session as a Client . . . . . . . . . . 26 114 5.3.2. Accepting a Session as a Server . . . . . . . . . . . 28 115 5.4. Closing a Session . . . . . . . . . . . . . . . . . . . . 29 116 6. MIB Module Overview . . . . . . . . . . . . . . . . . . . . . 29 117 6.1. Structure of the MIB Module . . . . . . . . . . . . . . . 30 118 6.2. Textual Conventions . . . . . . . . . . . . . . . . . . . 30 119 6.3. Statistical Counters . . . . . . . . . . . . . . . . . . . 30 120 6.4. Configuration Tables . . . . . . . . . . . . . . . . . . . 30 121 6.4.1. Notifications . . . . . . . . . . . . . . . . . . . . 30 122 6.5. Relationship to Other MIB Modules . . . . . . . . . . . . 30 123 6.5.1. MIB Modules Required for IMPORTS . . . . . . . . . . . 31 124 7. MIB Module Definition . . . . . . . . . . . . . . . . . . . . 31 125 8. Operational Considerations . . . . . . . . . . . . . . . . . . 54 126 8.1. Sessions . . . . . . . . . . . . . . . . . . . . . . . . . 54 127 8.2. Notification Receiver Credential Selection . . . . . . . . 54 128 8.3. contextEngineID Discovery . . . . . . . . . . . . . . . . 55 129 8.4. Transport Considerations . . . . . . . . . . . . . . . . . 55 130 9. Security Considerations . . . . . . . . . . . . . . . . . . . 55 131 9.1. Certificates, Authentication, and Authorization . . . . . 55 132 9.2. (D)TLS Security Considerations . . . . . . . . . . . . . . 56 133 9.2.1. TLS Version Requirements . . . . . . . . . . . . . . . 56 134 9.2.2. Perfect Forward Secrecy . . . . . . . . . . . . . . . 57 135 9.3. Use with SNMPv1/SNMPv2c Messages . . . . . . . . . . . . . 57 136 9.4. MIB Module Security . . . . . . . . . . . . . . . . . . . 57 137 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 59 138 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 59 139 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 60 140 12.1. Normative References . . . . . . . . . . . . . . . . . . . 60 141 12.2. Informative References . . . . . . . . . . . . . . . . . . 62 142 Appendix A. Target and Notification Configuration Example . . . . 62 143 A.1. Configuring a Notification Originator . . . . . . . . . . 62 144 A.2. Configuring TLSTM to Utilize a Simple Derivation of 145 tmSecurityName . . . . . . . . . . . . . . . . . . . . . . 63 146 A.3. Configuring TLSTM to Utilize Table-Driven Certificate 147 Mapping . . . . . . . . . . . . . . . . . . . . . . . . . 64 148 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 64 150 1. Introduction 152 It is important to understand the modular SNMPv3 architecture as 153 defined by [RFC3411] and enhanced by the Transport Subsystem 154 [RFC5590]. It is also important to understand the terminology of the 155 SNMPv3 architecture in order to understand where the Transport Model 156 described in this document fits into the architecture and how it 157 interacts with the other architecture subsystems. For a detailed 158 overview of the documents that describe the current Internet-Standard 159 Management Framework, please refer to Section 7 of [RFC3410]. 161 This document describes a Transport Model that makes use of the 162 Transport Layer Security (TLS) [RFC5246] and the Datagram Transport 163 Layer Security (DTLS) Protocol [RFC4347], within a transport 164 subsystem [RFC5590]. DTLS is the datagram variant of the Transport 165 Layer Security (TLS) protocol [RFC5246]. The Transport Model in this 166 document is referred to as the Transport Layer Security Transport 167 Model (TLSTM). TLS and DTLS take advantage of the X.509 public 168 keying infrastructure [RFC5280]. While (D)TLS supports multiple 169 authentication mechanisms, this document only discusses X.509 170 certificate based authentication. Although other forms of 171 authentication are possible they are outside the scope of this 172 specification. This transport model is designed to meet the security 173 and operational needs of network administrators, operating in both 174 environments where a connectionless (e.g. UDP) transport is 175 preferred and in environments where large quantities of data need to 176 be sent (e.g. over a TCP based stream). Both TLS and DTLS integrate 177 well into existing public keying infrastructures. This document 178 supports sending of SNMP messages over TLS/TCP and DTLS/UDP. 180 This document also defines a portion of the Management Information 181 Base (MIB) for use with network management protocols. In particular 182 it defines objects for managing the TLS Transport Model for SNMP. 184 Managed objects are accessed via a virtual information store, termed 185 the Management Information Base or MIB. MIB objects are generally 186 accessed through the Simple Network Management Protocol (SNMP). 187 Objects in the MIB are defined using the mechanisms defined in the 188 Structure of Management Information (SMI). This memo specifies a MIB 189 module that is compliant to the SMIv2, which is described in STD 58: 190 [RFC2578], [RFC2579] and [RFC2580]. 192 The diagram shown below gives a conceptual overview of two SNMP 193 entities communicating using the TLS Transport Model (shown as "TLS 194 TM"). One entity contains a command responder and notification 195 originator application, and the other a command generator and 196 notification receiver application. It should be understood that this 197 particular mix of application types is an example only and other 198 combinations are equally valid. Note: this diagram shows the 199 Transport Security Model (TSM) being used as the security model which 200 is defined in [RFC5591]. 202 +---------------------------------------------------------------------+ 203 | Network | 204 +---------------------------------------------------------------------+ 205 ^ | ^ | 206 |Notifications |Commands |Commands |Notifications 207 +---|---------------------|-------+ +--|---------------|--------------+ 208 | | V | | | V | 209 | +------------+ +------------+ | | +-----------+ +----------+ | 210 | | (D)TLS | | (D)TLS | | | | (D)TLS | | (D)TLS | | 211 | | (Client) | | (Server) | | | | (Client) | | (Server) | | 212 | +------------+ +------------+ | | +-----------+ +----------+ | 213 | ^ ^ | | ^ ^ | 214 | | | | | | | | 215 | +-------------+ | | +--------------+ | 216 | +-----|------------+ | | +-----|------------+ | 217 | | V | | | | V | | 218 | | +--------+ | +-----+ | | | +--------+ | +-----+ | 219 | | | TLS TM |<--------->|Cache| | | | | TLS TM |<--------->|Cache| | 220 | | +--------+ | +-----+ | | | +--------+ | +-----+ | 221 | |Transport Subsys. | ^ | | |Transport Subsys. | ^ | 222 | +------------------+ | | | +------------------+ | | 223 | ^ | | | ^ | | 224 | | +--+ | | | +--+ | 225 | v | | | V | | 226 | +-----+ +--------+ +-------+ | | | +-----+ +--------+ +-------+ | | 227 | | | |Message | |Securi.| | | | | | |Message | |Securi.| | | 228 | |Disp.| |Proc. | |Subsys.| | | | |Disp.| |Proc. | |Subsys.| | | 229 | | | |Subsys. | | | | | | | | |Subsys. | | | | | 230 | | | | | | | | | | | | | | | | | | 231 | | | | +----+ | | +---+ | | | | | | | +----+ | | +---+ | | | 232 | | <--->|v3MP|<--> |TSM|<--+ | | | <--->|v3MP|<--->|TSM|<--+ | 233 | | | | +----+ | | +---+ | | | | | | +----+ | | +---+ | | 234 | | | | | | | | | | | | | | | | 235 | +-----+ +--------+ +-------+ | | +-----+ +--------+ +-------+ | 236 | ^ | | ^ | 237 | | | | | | 238 | +-+------------+ | | +-+----------+ | 239 | | | | | | | | 240 | v v | | v V | 241 | +-------------+ +-------------+ | | +-------------+ +-------------+ | 242 | | COMMAND | | NOTIFICAT. | | | | COMMAND | | NOTIFICAT. | | 243 | | RESPONDER | | ORIGINATOR | | | | GENERATOR | | RECEIVER | | 244 | | application | | application | | | | application | | application | | 245 | +-------------+ +-------------+ | | +-------------+ +-------------+ | 246 | SNMP entity | | SNMP entity | 247 +---------------------------------+ +---------------------------------+ 249 1.1. Conventions 251 For consistency with SNMP-related specifications, this document 252 favors terminology as defined in STD 62, rather than favoring 253 terminology that is consistent with non-SNMP specifications. This is 254 consistent with the IESG decision to not require the SNMPv3 255 terminology be modified to match the usage of other non-SNMP 256 specifications when SNMPv3 was advanced to Full Standard. 258 "Authentication" in this document typically refers to the English 259 meaning of "serving to prove the authenticity of" the message, not 260 data source authentication or peer identity authentication. 262 The terms "manager" and "agent" are not used in this document 263 because, in the [RFC3411] architecture, all SNMP entities have the 264 capability of acting as manager, agent, or both depending on the SNMP 265 application types supported in the implementation. Where distinction 266 is required, the application names of command generator, command 267 responder, notification originator, notification receiver, and proxy 268 forwarder are used. See "SNMP Applications" [RFC3413] for further 269 information. 271 Large portions of this document simultaneously refer to both TLS and 272 DTLS when discussing TLSTM components that function equally with 273 either protocol. "(D)TLS" is used in these places to indicate that 274 the statement applies to either or both protocols as appropriate. 275 When a distinction between the protocols is needed they are referred 276 to independently through the use of "TLS" or "DTLS". The Transport 277 Model, however, is named "TLS Transport Model" and refers not to the 278 TLS or DTLS protocol but to the specification in this document, which 279 includes support for both TLS and DTLS. 281 Throughout this document, the terms "client" and "server" are used to 282 refer to the two ends of the (D)TLS transport connection. The client 283 actively opens the (D)TLS connection, and the server passively 284 listens for the incoming (D)TLS connection. An SNMP entity may act 285 as a (D)TLS client or server or both, depending on the SNMP 286 applications supported. 288 The User-Based Security Model (USM) [RFC3414] is a mandatory-to- 289 implement Security Model in STD 62. While (D)TLS and USM frequently 290 refer to a user, the terminology preferred in RFC3411 and in this 291 memo is "principal". A principal is the "who" on whose behalf 292 services are provided or processing takes place. A principal can be, 293 among other things, an individual acting in a particular role; a set 294 of individuals, with each acting in a particular role; an application 295 or a set of applications, or a combination of these within an 296 administrative domain. 298 Throughout this document, the term "session" is used to refer to a 299 secure association between two TLS Transport Models that permits the 300 transmission of one or more SNMP messages within the lifetime of the 301 session. The (D)TLS protocols also have an internal notion of a 302 session and although these two concepts of a session are related, 303 when the term "session" is used this document is referring to the 304 TLSTM's specific session and not directly to the (D)TLS protocol's 305 session. 307 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 308 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 309 document are to be interpreted as described in [RFC2119]. 311 2. The Transport Layer Security Protocol 313 (D)TLS provides authentication, data message integrity, and privacy 314 at the transport layer. (See [RFC4347]) 316 The primary goals of the TLS Transport Model are to provide privacy, 317 peer identity authentication and data integrity between two 318 communicating SNMP entities. The TLS and DTLS protocols provide a 319 secure transport upon which the TLSTM is based. Please refer to 320 [RFC5246] and [RFC4347] for complete descriptions of the protocols. 322 3. How the TLSTM fits into the Transport Subsystem 324 A transport model is a component of the Transport Subsystem. The TLS 325 Transport Model thus fits between the underlying (D)TLS transport 326 layer and the Message Dispatcher [RFC3411] component of the SNMP 327 engine. 329 The TLS Transport Model will establish a session between itself and 330 the TLS Transport Model of another SNMP engine. The sending 331 transport model passes unencrypted and unauthenticated messages from 332 the Dispatcher to (D)TLS to be encrypted and authenticated, and the 333 receiving transport model accepts decrypted and authenticated/ 334 integrity-checked incoming messages from (D)TLS and passes them to 335 the Dispatcher. 337 After a TLS Transport Model session is established, SNMP messages can 338 conceptually be sent through the session from one SNMP message 339 Dispatcher to another SNMP Message Dispatcher. If multiple SNMP 340 messages are needed to be passed between two SNMP applications they 341 MAY be passed through the same session. A TLSTM implementation 342 engine MAY choose to close the session to conserve resources. 344 The TLS Transport Model of an SNMP engine will perform the 345 translation between (D)TLS-specific security parameters and SNMP- 346 specific, model-independent parameters. 348 The diagram below depicts where the TLS Transport Model (shown as 349 "(D)TLS TM") fits into the architecture described in RFC3411 and the 350 Transport Subsystem: 352 +------------------------------+ 353 | Network | 354 +------------------------------+ 355 ^ ^ ^ 356 | | | 357 v v v 358 +-------------------------------------------------------------------+ 359 | +--------------------------------------------------+ | 360 | | Transport Subsystem | +--------+ | 361 | | +-----+ +-----+ +-------+ +-------+ | | | | 362 | | | UDP | | SSH | |(D)TLS | . . . | other |<--->| Cache | | 363 | | | | | TM | | TM | | | | | | | 364 | | +-----+ +-----+ +-------+ +-------+ | +--------+ | 365 | +--------------------------------------------------+ ^ | 366 | ^ | | 367 | | | | 368 | Dispatcher v | | 369 | +--------------+ +---------------------+ +----------------+ | | 370 | | Transport | | Message Processing | | Security | | | 371 | | Dispatch | | Subsystem | | Subsystem | | | 372 | | | | +------------+ | | +------------+ | | | 373 | | | | +->| v1MP |<--->| | USM | | | | 374 | | | | | +------------+ | | +------------+ | | | 375 | | | | | +------------+ | | +------------+ | | | 376 | | | | +->| v2cMP |<--->| | Transport | | | | 377 | | Message | | | +------------+ | | | Security |<--+ | 378 | | Dispatch <---->| +------------+ | | | Model | | | 379 | | | | +->| v3MP |<--->| +------------+ | | 380 | | | | | +------------+ | | +------------+ | | 381 | | PDU Dispatch | | | +------------+ | | | Other | | | 382 | +--------------+ | +->| otherMP |<--->| | Model(s) | | | 383 | ^ | +------------+ | | +------------+ | | 384 | | +---------------------+ +----------------+ | 385 | v | 386 | +-------+-------------------------+---------------+ | 387 | ^ ^ ^ | 388 | | | | | 389 | v v v | 390 | +-------------+ +---------+ +--------------+ +-------------+ | 391 | | COMMAND | | ACCESS | | NOTIFICATION | | PROXY | | 392 | | RESPONDER |<->| CONTROL |<->| ORIGINATOR | | FORWARDER | | 393 | | application | | | | applications | | application | | 394 | +-------------+ +---------+ +--------------+ +-------------+ | 395 | ^ ^ | 396 | | | | 397 | v v | 398 | +----------------------------------------------+ | 399 | | MIB instrumentation | SNMP entity | 400 +-------------------------------------------------------------------+ 402 3.1. Security Capabilities of this Model 404 3.1.1. Threats 406 The TLS Transport Model provides protection against the threats 407 identified by the RFC 3411 architecture [RFC3411]: 409 1. Modification of Information - The modification threat is the 410 danger that an unauthorized entity may alter in-transit SNMP 411 messages generated on behalf of an authorized principal in such a 412 way as to effect unauthorized management operations, including 413 falsifying the value of an object. 415 (D)TLS provides verification that the content of each received 416 message has not been modified during its transmission through the 417 network, data has not been altered or destroyed in an 418 unauthorized manner, and data sequences have not been altered to 419 an extent greater than can occur non-maliciously. 421 2. Masquerade - The masquerade threat is the danger that management 422 operations unauthorized for a given principal may be attempted by 423 assuming the identity of another principal that has the 424 appropriate authorizations. 426 The TLSTM verifies of the identity of the (D)TLS server through 427 the use of the (D)TLS protocol and X.509 certificates. A TLS 428 Transport Model implementation MUST support authentication of 429 both the server and the client. 431 3. Message stream modification - The re-ordering, delay or replay of 432 messages can and does occur through the natural operation of many 433 connectionless transport services. The message stream 434 modification threat is the danger that messages may be 435 maliciously re-ordered, delayed or replayed to an extent which is 436 greater than can occur through the natural operation of 437 connectionless transport services, in order to effect 438 unauthorized management operations. 440 (D)TLS provides replay protection with a MAC that includes a 441 sequence number. Since UDP provides no sequencing ability, DTLS 442 uses a sliding window protocol with the sequence number used for 443 replay protection (see [RFC4347]). 445 4. Disclosure - The disclosure threat is the danger of eavesdropping 446 on the exchanges between SNMP engines. 448 (D)TLS provides protection against the disclosure of information 449 to unauthorized recipients or eavesdroppers by allowing for 450 encryption of all traffic between SNMP engines. A TLS Transport 451 Model implementation MUST support message encryption to protect 452 sensitive data from eavesdropping attacks. 454 5. Denial of Service - the RFC 3411 architecture [RFC3411] states 455 that denial of service (DoS) attacks need not be addressed by an 456 SNMP security protocol. However, connectionless transports (like 457 DTLS over UDP) are susceptible to a variety of denial of service 458 attacks because they are more vulnerable to spoofed IP addresses. 459 See Section 4.2 for details how the cookie mechanism is used. 460 Note, however, that this mechanism does not provide any defense 461 against denial of service attacks mounted from valid IP 462 addresses. 464 See Section 9 for more detail on the security considerations 465 associated with the TLSTM and these security threats. 467 3.1.2. Message Protection 469 The RFC 3411 architecture recognizes three levels of security: 471 o without authentication and without privacy (noAuthNoPriv) 473 o with authentication but without privacy (authNoPriv) 475 o with authentication and with privacy (authPriv) 477 The TLS Transport Model determines from (D)TLS the identity of the 478 authenticated principal, the transport type and the transport address 479 associated with an incoming message. The TLS Transport Model 480 provides the identity and destination type and address to (D)TLS for 481 outgoing messages. 483 When an application requests a session for a message it also requests 484 a security level for that session. The TLS Transport Model MUST 485 ensure that the (D)TLS connection provides security at least as high 486 as the requested level of security. How the security level is 487 translated into the algorithms used to provide data integrity and 488 privacy is implementation-dependent. However, the NULL integrity and 489 encryption algorithms MUST NOT be used to fulfill security level 490 requests for authentication or privacy. Implementations MAY choose 491 to force (D)TLS to only allow cipher_suites that provide both 492 authentication and privacy to guarantee this assertion. 494 If a suitable interface between the TLS Transport Model and the 495 (D)TLS Handshake Protocol is implemented to allow the selection of 496 security level dependent algorithms (for example a security level to 497 cipher_suites mapping table) then different security levels may be 498 utilized by the application. 500 The authentication, integrity and privacy algorithms used by the 501 (D)TLS Protocols may vary over time as the science of cryptography 502 continues to evolve and the development of (D)TLS continues over 503 time. Implementers are encouraged to plan for changes in operator 504 trust of particular algorithms. Implementations SHOULD offer 505 configuration settings for mapping algorithms to SNMPv3 security 506 levels. 508 3.1.3. (D)TLS Connections 510 (D)TLS connections are opened by the TLS Transport Model during the 511 elements of procedure for an outgoing SNMP message. Since the sender 512 of a message initiates the creation of a (D)TLS connection if needed, 513 the (D)TLS connection will already exist for an incoming message. 515 Implementations MAY choose to instantiate (D)TLS connections in 516 anticipation of outgoing messages. This approach might be useful to 517 ensure that a (D)TLS connection to a given target can be established 518 before it becomes important to send a message over the (D)TLS 519 connection. Of course, there is no guarantee that a pre-established 520 session will still be valid when needed. 522 DTLS connections, when used over UDP, are uniquely identified within 523 the TLS Transport Model by the combination of transportDomain, 524 transportAddress, tmSecurityName, and requestedSecurityLevel 525 associated with each session. Each unique combination of these 526 parameters MUST have a locally-chosen unique tlstmSessionID for each 527 active session. For further information see Section 5. TLS over TCP 528 sessions, on the other hand, do not require a unique pairing of 529 address and port attributes since their lower layer protocols (TCP) 530 already provide adequate session framing. But they must still 531 provide a unique tlstmSessionID for referencing the session. 533 The tlstmSessionID identifier MUST NOT change during the entire 534 duration of the session from the TLSTM's perspective, and MUST 535 uniquely identify a single session. As an implementation hint: note 536 that the (D)TLS internal SessionID does not meet these requirements, 537 since it can change over the life of the connection as seen by the 538 TLSTM (for example, during renegotiation), and does not necessarily 539 uniquely identify a TLSTM session (there can be multiple TLSTM 540 sessions sharing the same D(TLS) internal SessionID). 542 3.2. Security Parameter Passing 544 For the (D)TLS server-side, (D)TLS-specific security parameters 545 (i.e., cipher_suites, X.509 certificate fields, IP address and port) 546 are translated by the TLS Transport Model into security parameters 547 for the TLS Transport Model and security model (e.g., 548 tmSecurityLevel, tmSecurityName, transportDomain, transportAddress). 549 The transport-related and (D)TLS-security-related information, 550 including the authenticated identity, are stored in a cache 551 referenced by tmStateReference. 553 For the (D)TLS client-side, the TLS Transport Model takes input 554 provided by the Dispatcher in the sendMessage() Abstract Service 555 Interface (ASI) and input from the tmStateReference cache. The 556 (D)TLS Transport Model converts that information into suitable 557 security parameters for (D)TLS and establishes sessions as needed. 559 The elements of procedure in Section 5 discuss these concepts in much 560 greater detail. 562 3.3. Notifications and Proxy 564 (D)TLS connections may be initiated by (D)TLS clients on behalf of 565 SNMP appplications that initiate communications, such as command 566 generators, notification originators, proxy forwarders. Command 567 generators are frequently operated by a human, but notification 568 originators and proxy forwarders are usually unmanned automated 569 processes. The targets to whom notifications and proxied requests 570 should be sent is typically determined and configured by a network 571 administrator. 573 The SNMP-TARGET-MIB module [RFC3413] contains objects for defining 574 management targets, including transportDomain, transportAddress, 575 securityName, securityModel, and securityLevel parameters, for 576 notification originator, proxy forwarder, and SNMP-controllable 577 command generator applications. Transport domains and transport 578 addresses are configured in the snmpTargetAddrTable, and the 579 securityModel, securityName, and securityLevel parameters are 580 configured in the snmpTargetParamsTable. This document defines a MIB 581 module that extends the SNMP-TARGET-MIB's snmpTargetParamsTable to 582 specify a (D)TLS client-side certificate to use for the connection. 584 When configuring a (D)TLS target, the snmpTargetAddrTDomain and 585 snmpTargetAddrTAddress parameters in snmpTargetAddrTable SHOULD be 586 set to the snmpTLSTCPDomain or snmpDTLSUDPDomain object and an 587 appropriate snmpTLSAddress value. When used with the SNMPv3 message 588 processing model, the snmpTargetParamsMPModel column of the 589 snmpTargetParamsTable SHOULD be set to a value of 3. The 590 snmpTargetParamsSecurityName SHOULD be set to an appropriate 591 securityName value and the snmpTlstmParamsClientFingerprint parameter 592 of the snmpTlstmParamsTable SHOULD be set a value that refers to a 593 locally held certificate (and the corresponding private key) to be 594 used. Other parameters, for example cryptographic configuration such 595 as which cipher suites to use, must come from configuration 596 mechanisms not defined in this document. 598 The securityName defined in the snmpTargetParamsSecurityName column 599 will be used by the access control model to authorize any 600 notifications that need to be sent. 602 4. Elements of the Model 604 This section contains definitions required to realize the (D)TLS 605 Transport Model defined by this document. 607 4.1. X.509 Certificates 609 (D)TLS can make use of X.509 certificates for authentication of both 610 sides of the transport. This section discusses the use of X.509 611 certificates in the TLSTM. 613 While (D)TLS supports multiple authentication mechanisms, this 614 document only discusses X.509 certificate based authentication; other 615 forms of authentication are outside the scope of this specification. 616 TLSTM implementations are REQUIRED to support X.509 certificates. 618 4.1.1. Provisioning for the Certificate 620 Authentication using (D)TLS will require that SNMP entities have 621 certificates, either signed by trusted certification authorities, or 622 self-signed. Furthermore, SNMP entities will most commonly need to 623 be provisioned with root certificates which represent the list of 624 trusted certificate authorities that an SNMP entity can use for 625 certificate verification. SNMP entities SHOULD also be provisioned 626 with a X.509 certificate revocation mechanism which can be used to 627 verify that a certificate has not been revoked. Trusted public keys 628 from either CA certificates and/or self-signed certificates MUST be 629 installed into the server through a trusted out of band mechanism and 630 their authenticity MUST be verified before access is granted. 632 Having received a certificate from a connecting TLSTM client, the 633 authenticated tmSecurityName of the principal is derived using the 634 snmpTlstmCertToTSNTable. This table allows mapping of incoming 635 connections to tmSecurityNames through defined transformations. The 636 transformations defined in the SNMP-TLS-TM-MIB include: 638 o Mapping a certificate's subjectAltName or CommonName components to 639 a tmSecurityName, or 641 o Mapping a certificate's fingerprint value to a directly specified 642 tmSecurityName 644 As an implementation hint: implementations may choose to discard any 645 connections for which no potential snmpTlstmCertToTSNTable mapping 646 exists before performing certificate verification to avoid expending 647 computational resources associated with certificate verification. 649 Deployments SHOULD map the "subjectAltName" component of X.509 650 certificates to the TLSTM specific tmSecurityNames. The 651 authenticated identity can be obtained by the TLS Transport Model by 652 extracting the subjectAltName(s) from the peer's certificate. The 653 receiving application will then have an appropriate tmSecurityName 654 for use by other SNMPv3 components like an access control model. 656 An example of this type of mapping setup can be found in Appendix A. 658 This tmSecurityName may be later translated from a TLSTM specific 659 tmSecurityName to a SNMP engine securityName by the security model. 660 A security model, like the TSM security model [RFC5591], may perform 661 an identity mapping or a more complex mapping to derive the 662 securityName from the tmSecurityName offered by the TLS Transport 663 Model. 665 The standard VACM access control model constrains securityNames to be 666 32 octets or less in length. A TLSTM generated tmSecurityName, 667 possibly in combination with a messaging or security model that 668 increases the length of the securityName, might cause the 669 securityName length to exceed 32 octets. For example, a 32 octet 670 tmSecurityName derived from an IPv6 address, paired with a TSM 671 prefix, will generate a 36 octet securityName. Such a securityName 672 will not be able to be used with standard VACM or TARGET MIB modules. 673 Operators should be careful to select algorithms and subjectAltNames 674 to avoid this situation. 676 A pictorial view of the complete transformation process (using the 677 TSM security model for the example) is shown below: 679 +-------------+ +-------+ +-----+ 680 | Certificate | | | | | 681 | Path | | TLSTM | tmSecurityName | TSM | 682 | Validation | --> | | ----------------->| | 683 +-------------+ +-------+ +-----+ 684 | 685 | securityName 686 V 687 +-------------+ 688 | application | 689 +-------------+ 691 4.2. (D)TLS Usage 693 (D)TLS MUST negotiate a cipher suite that uses X.509 certificates for 694 authentication, and MUST authenticate both the client and the server. 695 The mandatory-to-implement cipher suite is specified in the TLS 696 specification [RFC5246]. 698 TLSTM verifies the certificates when the connection is opened (see 699 Section 5.3). For this reason, TLS renegotiation with different 700 certificates MUST NOT be done. That is, implementations MUST either 701 disable renegotiation completely (RECOMMENDED), or MUST present the 702 same certificate during renegotiation (and MUST verify that the other 703 end presented the same certificate). 705 For DTLS over UDP, each SNMP message MUST be placed in a single UDP 706 datagram; it MAY be split to multiple DTLS records. In other words, 707 if a single datagram contains multiple DTLS application_data records, 708 they are concatenated when received. The TLSTM implementation SHOULD 709 return an error if the SNMP message does not fit in the UDP datagram, 710 and thus cannot be sent. 712 For DTLS over UDP, the DTLS server implementation MUST support DTLS 713 cookies ([RFC4347] already requires that clients support DTLS 714 cookies). Implementations are not required to perform the cookie 715 exchange for every DTLS handshake; however, enabling it by default is 716 RECOMMENDED. 718 For DTLS, replay protection MUST be used. 720 4.3. SNMP Services 722 This section describes the services provided by the TLS Transport 723 Model with their inputs and outputs. The services are between the 724 Transport Model and the Dispatcher. 726 The services are described as primitives of an abstract service 727 interface (ASI) and the inputs and outputs are described as abstract 728 data elements as they are passed in these abstract service 729 primitives. 731 4.3.1. SNMP Services for an Outgoing Message 733 The Dispatcher passes the information to the TLS Transport Model 734 using the ASI defined in the transport subsystem: 736 statusInformation = 737 sendMessage( 738 IN destTransportDomain -- transport domain to be used 739 IN destTransportAddress -- transport address to be used 740 IN outgoingMessage -- the message to send 741 IN outgoingMessageLength -- its length 742 IN tmStateReference -- reference to transport state 743 ) 745 The abstract data elements returned from or passed as parameters into 746 the abstract service primitives are as follows: 748 statusInformation: An indication of whether the sending of the 749 message was successful. If not, it is an indication of the 750 problem. 752 destTransportDomain: The transport domain for the associated 753 destTransportAddress. The Transport Model uses this parameter to 754 determine the transport type of the associated 755 destTransportAddress. This document specifies the 756 snmpTLSTCPDomain and the snmpDTLSUDPDomain transport domains. 758 destTransportAddress: The transport address of the destination TLS 759 Transport Model in a format specified by the SnmpTLSAddress 760 TEXTUAL-CONVENTION. 762 outgoingMessage: The outgoing message to send to (D)TLS for 763 encapsulation and transmission. 765 outgoingMessageLength: The length of the outgoingMessage. 767 tmStateReference: A reference used to pass model-specific and 768 mechanism-specific parameters between the Transport Subsystem and 769 transport-aware Security Models. 771 4.3.2. SNMP Services for an Incoming Message 773 The TLS Transport Model processes the received message from the 774 network using the (D)TLS service and then passes it to the Dispatcher 775 using the following ASI: 777 statusInformation = 778 receiveMessage( 779 IN transportDomain -- origin transport domain 780 IN transportAddress -- origin transport address 781 IN incomingMessage -- the message received 782 IN incomingMessageLength -- its length 783 IN tmStateReference -- reference to transport state 784 ) 786 The abstract data elements returned from or passed as parameters into 787 the abstract service primitives are as follows: 789 statusInformation: An indication of whether the passing of the 790 message was successful. If not, it is an indication of the 791 problem. 793 transportDomain: The transport domain for the associated 794 transportAddress. This document specifies the snmpTLSTCPDomain 795 and the snmpDTLSUDPDomain transport domains. 797 transportAddress: The transport address of the source of the 798 received message in a format specified by the SnmpTLSAddress 799 TEXTUAL-CONVENTION. 801 incomingMessage: The whole SNMP message after being processed by 802 (D)TLS. 804 incomingMessageLength: The length of the incomingMessage. 806 tmStateReference: A reference used to pass model-specific and 807 mechanism-specific parameters between the Transport Subsystem and 808 transport-aware Security Models. 810 4.4. Cached Information and References 812 When performing SNMP processing, there are two levels of state 813 information that may need to be retained: the immediate state linking 814 a request-response pair, and potentially longer-term state relating 815 to transport and security. "Transport Subsystem for the Simple 816 Network Management Protocol" [RFC5590] defines general requirements 817 for caches and references. 819 4.4.1. TLS Transport Model Cached Information 821 The TLS Transport Model has specific responsibilities regarding the 822 cached information. See the Elements of Procedure in Section 5 for 823 detailed processing instructions on the use of the tmStateReference 824 fields by the TLS Transport Model. 826 4.4.1.1. tmSecurityName 828 The tmSecurityName MUST be a human-readable name (in snmpAdminString 829 format) representing the identity that has been set according to the 830 procedures in Section 5. The tmSecurityName MUST be constant for all 831 traffic passing through a single TLSTM session. Messages MUST NOT be 832 sent through an existing (D)TLS connection that was established using 833 a different tmSecurityName. 835 On the (D)TLS server side of a connection the tmSecurityName is 836 derived using the procedures described in Section 5.3.2 and the SNMP- 837 TLS-TM-MIB's snmpTlstmCertToTSNTable DESCRIPTION clause. 839 On the (D)TLS client side of a connection the tmSecurityName is 840 presented to the TLS Transport Model by the application (possibly 841 because of configuration specified in the SNMP-TARGET-MIB). The 842 Security Model likely derived the tmSecurityName from the 843 securityName presented to the Security Model by the application 844 (possibly because of configuration specified in the SNMP-TARGET-MIB). 846 Transport-model-aware security models derive tmSecurityName from a 847 securityName, possibly configured in MIB modules for notifications 848 and access controls. Transport Models SHOULD use predictable 849 tmSecurityNames so operators will know what to use when configuring 850 MIB modules that use securityNames derived from tmSecurityNames. The 851 TLSTM generates predictable tmSecurityNames based on the 852 configuration found in the SNMP-TLS-TM-MIB's snmpTlstmCertToTSNTable 853 and relies on the network operators to have configured this table 854 appropriately. 856 4.4.1.2. tmSessionID 858 The tmSessionID MUST be recorded per message at the time of receipt. 859 When tmSameSecurity is set, the recorded tmSessionID can be used to 860 determine whether the (D)TLS connection available for sending a 861 corresponding outgoing message is the same (D)TLS connection as was 862 used when receiving the incoming message (e.g., a response to a 863 request). 865 4.4.1.3. Session State 867 The per-session state that is referenced by tmStateReference may be 868 saved across multiple messages in a Local Configuration Datastore. 869 Additional session/connection state information might also be stored 870 in a Local Configuration Datastore. 872 5. Elements of Procedure 874 Abstract service interfaces have been defined by [RFC3411] and 875 further augmented by [RFC5590] to describe the conceptual data flows 876 between the various subsystems within an SNMP entity. The TLSTM uses 877 some of these conceptual data flows when communicating between 878 subsystems. 880 To simplify the elements of procedure, the release of state 881 information is not always explicitly specified. As a general rule, 882 if state information is available when a message gets discarded, the 883 message-state information should also be released. If state 884 information is available when a session is closed, the session state 885 information should also be released. Sensitive information, like 886 cryptographic keys, should be overwritten appropriately prior to 887 being released. 889 An error indication in statusInformation will typically include the 890 Object Identifier (OID) and value for an incremented error counter. 891 This may be accompanied by the requested securityLevel and the 892 tmStateReference. Per-message context information is not accessible 893 to Transport Models, so for the returned counter OID and value, 894 contextEngine would be set to the local value of snmpEngineID and 895 contextName to the default context for error counters. 897 5.1. Procedures for an Incoming Message 899 This section describes the procedures followed by the (D)TLS 900 Transport Model when it receives a (D)TLS protected packet. The 901 required functionality is broken into two different sections. 903 Section 5.1.1 describes the processing required for de-multiplexing 904 multiple DTLS connections, which is specifically needed for DTLS over 905 UDP sessions. It is assumed that TLS protocol implementations 906 already provide appropriate message demultiplexing. 908 Section 5.1.2 describes the transport processing required once the 909 (D)TLS processing has been completed. This will be needed for all 910 (D)TLS-based connections. 912 5.1.1. DTLS over UDP Processing for Incoming Messages 914 For connection-oriented transport protocols, such as TCP, the 915 transport protocol takes care of demultiplexing incoming packets to 916 the right connection. Depending on the DTLS implementation, for DTLS 917 over UDP, this demultiplexing may need to be done by the TLSTM 918 implementation. 920 Like TCP, DTLS over UDP uses the four-tuple for identifying the connection 922 (and relevant DTLS connection state). This means that when 923 establishing a new session, implementations MUST use a different UDP 924 source port number for each active connection to a remote destination 925 IP-address/port-number combination to ensure the remote entity can 926 disambiguate between multiple connections. 928 If demultiplexing received UDP datagrams to DTLS connection state is 929 done by the TLSTM implementation (instead of the DTLS 930 implementation), the steps below describe one possible method to 931 accomplish this. 933 The important output results from the steps in this process are the 934 remote transport address, incomingMessage, incomingMessageLength, and 935 the tlstmSessionID. 937 1) The TLS Transport Model examines the raw UDP message, in an 938 implementation-dependent manner. 940 2) The TLS Transport Model queries the Local Configuration Datastore 941 (LCD) (see [RFC3411] Section 3.4.2) using the transport 942 parameters (source and destination IP addresses and ports) to 943 determine if a session already exists. 945 2a) If a matching entry in the LCD does not exist, then the UDP 946 packet is passed to the DTLS implementation for processing. 947 If the DTLS implementation decides to continue with the 948 connection and allocate state for it, it returns a new DTLS 949 connection handle (an implementation dependent detail). In 950 this case, TLSTM selects a new tlstmSessionId, and caches 951 this and the DTLS connection handle as a new entry in the 952 LCD (indexed by the transport parameters). If the DTLS 953 implementation returns an error or does not allocate 954 connection state (which can happen with the stateless cookie 955 exchange), processing stops. 957 2b) If a session does exist in the LCD then its DTLS connection 958 handle (an implementation dependent detail) and its 959 tlstmSessionId is extracted from the LCD. The UDP packet 960 and the connection handle is passed to the DTLS 961 implementation. If the DTLS implementation returns success 962 but does not return an incomingMessage and an 963 incomingMessageLength then processing stops (this is the 964 case when the UDP datagram contained DTLS handshake 965 messages, for example). If the DTLS implementation returns 966 an error then processing stops. 968 3) Retrieve the incomingMessage and an incomingMessageLength from 969 DTLS. These results and the tlstmSessionID are used below in 970 Section 5.1.2 to complete the processing of the incoming message. 972 5.1.2. Transport Processing for Incoming SNMP Messages 974 The procedures in this section describe how the TLS Transport Model 975 should process messages that have already been properly extracted 976 from the (D)TLS stream. Note that care must be taken when processing 977 messages originating from either TLS or DTLS to ensure they're 978 complete and single. For example, multiple SNMP messages can be 979 passed through a single DTLS message and partial SNMP messages may be 980 received from a TLS stream. These steps describe the processing of a 981 singular SNMP message after it has been delivered from the (D)TLS 982 stream. 984 1) Determine the tlstmSessionID for the incoming message. The 985 tlstmSessionID MUST be a unique session identifier for this 986 (D)TLS connection. The contents and format of this identifier 987 are implementation-dependent as long as it is unique to the 988 session. A session identifier MUST NOT be reused until all 989 references to it are no longer in use. The tmSessionID is equal 990 to the tlstmSessionID discussed in Section 5.1.1. tmSessionID 991 refers to the session identifier when stored in the 992 tmStateReference and tlstmSessionID refers to the session 993 identifier when stored in the LCD. They MUST always be equal 994 when processing a given session's traffic. 996 If this is the first message received through this session and 997 the session does not have an assigned tlstmSessionID yet then the 998 snmpTlstmSessionAccepts counter is incremented and a 999 tlstmSessionID for the session is created. This will only happen 1000 on the server side of a connection because a client would have 1001 already assigned a tlstmSessionID during the openSession() 1002 invocation. Implementations may have performed the procedures 1003 described in Section 5.3.2 prior to this point or they may 1004 perform them now, but the procedures described in Section 5.3.2 1005 MUST be performed before continuing beyond this point. 1007 2) Create a tmStateReference cache for the subsequent reference and 1008 assign the following values within it: 1010 tmTransportDomain = snmpTLSTCPDomain or snmpDTLSUDPDomain as 1011 appropriate. 1013 tmTransportAddress = The address the message originated from. 1015 tmSecurityLevel = The derived tmSecurityLevel for the session, 1016 as discussed in Section 3.1.2 and Section 5.3. 1018 tmSecurityName = The derived tmSecurityName for the session as 1019 discussed in Section 5.3. This value MUST be constant during 1020 the lifetime of the session. 1022 tmSessionID = The tlstmSessionID described in step 1 above. 1024 3) The incomingMessage and incomingMessageLength are assigned values 1025 from the (D)TLS processing. 1027 4) The TLS Transport Model passes the transportDomain, 1028 transportAddress, incomingMessage, and incomingMessageLength to 1029 the Dispatcher using the receiveMessage ASI: 1031 statusInformation = 1032 receiveMessage( 1033 IN transportDomain -- snmpTLSTCPDomain or snmpDTLSUDPDomain, 1034 IN transportAddress -- address for the received message 1035 IN incomingMessage -- the whole SNMP message from (D)TLS 1036 IN incomingMessageLength -- the length of the SNMP message 1037 IN tmStateReference -- transport info 1038 ) 1040 5.2. Procedures for an Outgoing SNMP Message 1042 The Dispatcher sends a message to the TLS Transport Model using the 1043 following ASI: 1045 statusInformation = 1046 sendMessage( 1047 IN destTransportDomain -- transport domain to be used 1048 IN destTransportAddress -- transport address to be used 1049 IN outgoingMessage -- the message to send 1050 IN outgoingMessageLength -- its length 1051 IN tmStateReference -- transport info 1052 ) 1054 This section describes the procedure followed by the TLS Transport 1055 Model whenever it is requested through this ASI to send a message. 1057 1) If tmStateReference does not refer to a cache containing values 1058 for tmTransportDomain, tmTransportAddress, tmSecurityName, 1059 tmRequestedSecurityLevel, and tmSameSecurity, then increment the 1060 snmpTlstmSessionInvalidCaches counter, discard the message, and 1061 return the error indication in the statusInformation. Processing 1062 of this message stops. 1064 2) Extract the tmSessionID, tmTransportDomain, tmTransportAddress, 1065 tmSecurityName, tmRequestedSecurityLevel, and tmSameSecurity 1066 values from the tmStateReference. Note: The tmSessionID value 1067 may be undefined if no session exists yet over which the message 1068 can be sent. 1070 3) If tmSameSecurity is true and either tmSessionID is undefined or 1071 refers to a session that is no longer open then increment the 1072 snmpTlstmSessionNoSessions counter, discard the message and 1073 return the error indication in the statusInformation. Processing 1074 of this message stops. 1076 4) If tmSameSecurity is false and tmSessionID refers to a session 1077 that is no longer available then an implementation SHOULD open a 1078 new session using the openSession() ASI (described in greater 1079 detail in step 5b). Instead of opening a new session an 1080 implementation MAY return a snmpTlstmSessionNoSessions error to 1081 the calling module and stop processing of the message. 1083 5) If tmSessionID is undefined, then use tmTransportDomain, 1084 tmTransportAddress, tmSecurityName and tmRequestedSecurityLevel 1085 to see if there is a corresponding entry in the LCD suitable to 1086 send the message over. 1088 5a) If there is a corresponding LCD entry, then this session 1089 will be used to send the message. 1091 5b) If there is no corresponding LCD entry, then open a session 1092 using the openSession() ASI (discussed further in 1093 Section 5.3.1). Implementations MAY wish to offer message 1094 buffering to prevent redundant openSession() calls for the 1095 same cache entry. If an error is returned from 1096 openSession(), then discard the message, discard the 1097 tmStateReference, increment the snmpTlstmSessionOpenErrors, 1098 return an error indication to the calling module and stop 1099 processing of the message. 1101 6) Using either the session indicated by the tmSessionID if there 1102 was one or the session resulting from a previous step (4 or 5), 1103 pass the outgoingMessage to (D)TLS for encapsulation and 1104 transmission. 1106 5.3. Establishing or Accepting a Session 1108 Establishing a (D)TLS connection as either a client or a server 1109 requires slightly different processing. The following two sections 1110 describe the necessary processing steps. 1112 5.3.1. Establishing a Session as a Client 1114 The TLS Transport Model provides the following primitive for use by a 1115 client to establish a new (D)TLS connection: 1117 statusInformation = -- errorIndication or success 1118 openSession( 1119 IN tmStateReference -- transport information to be used 1120 OUT tmStateReference -- transport information to be used 1121 IN maxMessageSize -- of the sending SNMP entity 1122 ) 1124 The following describes the procedure to follow when establishing a 1125 SNMP over (D)TLS connection between SNMP engines for exchanging SNMP 1126 messages. This process is followed by any SNMP client's engine when 1127 establishing a session for subsequent use. 1129 This procedure MAY be done automatically for an SNMP application that 1130 initiates a transaction, such as a command generator, a notification 1131 originator, or a proxy forwarder. 1133 1) The snmpTlstmSessionOpens counter is incremented. 1135 2) The client selects the appropriate certificate and cipher_suites 1136 for the key agreement based on the tmSecurityName and the 1137 tmRequestedSecurityLevel for the session. For sessions being 1138 established as a result of a SNMP-TARGET-MIB based operation, the 1139 certificate will potentially have been identified via the 1140 snmpTlstmParamsTable mapping and the cipher_suites will have to 1141 be taken from system-wide or implementation-specific 1142 configuration. If no row in the snmpTlstmParamsTable exists then 1143 implementations MAY choose to establish the connection using a 1144 default client certificate available to the application. 1145 Otherwise, the certificate and appropriate cipher_suites will 1146 need to be passed to the openSession() ASI as supplemental 1147 information or configured through an implementation-dependent 1148 mechanism. It is also implementation-dependent and possibly 1149 policy-dependent how tmRequestedSecurityLevel will be used to 1150 influence the security capabilities provided by the (D)TLS 1151 connection. However this is done, the security capabilities 1152 provided by (D)TLS MUST be at least as high as the level of 1153 security indicated by the tmRequestedSecurityLevel parameter. 1154 The actual security level of the session is reported in the 1155 tmStateReference cache as tmSecurityLevel. For (D)TLS to provide 1156 strong authentication, each principal acting as a command 1157 generator SHOULD have its own certificate. 1159 3) Using the destTransportDomain and destTransportAddress values, 1160 the client will initiate the (D)TLS handshake protocol to 1161 establish session keys for message integrity and encryption. 1163 If the attempt to establish a session is unsuccessful, then 1164 snmpTlstmSessionOpenErrors is incremented, an error indication is 1165 returned, and processing stops. If the session failed to open 1166 because the presented server certificate was unknown or invalid 1167 then the snmpTlstmSessionUnknownServerCertificate or 1168 snmpTlstmSessionInvalidServerCertificates MUST be incremented and 1169 a snmpTlstmServerCertificateUnknown or 1170 snmpTlstmServerInvalidCertificate notification SHOULD be sent as 1171 appropriate. Reasons for server certificate invalidation 1172 includes, but is not limited to, cryptographic validation 1173 failures and an unexpected presented certificate identity. 1175 4) The (D)TLS client MUST then verify that the (D)TLS server's 1176 presented certificate is the expected certificate. The (D)TLS 1177 client MUST NOT transmit SNMP messages until the server 1178 certificate has been authenticated, the client certificate has 1179 been transmitted and the TLS connection has been fully 1180 established. 1182 If the connection is being established from configuration based 1183 on SNMP-TARGET-MIB configuration, then the snmpTlstmAddrTable 1184 DESCRIPTION clause describes how the verification is done (using 1185 either a certificate fingerprint, or an identity authenticated 1186 via certification path validation). 1188 If the connection is being established for reasons other than 1189 configuration found in the SNMP-TARGET-MIB then configuration and 1190 procedures outside the scope of this document should be followed. 1191 Configuration mechanisms SHOULD be similar in nature to those 1192 defined in the snmpTlstmAddrTable to ensure consistency across 1193 management configuration systems. For example, a command-line 1194 tool for generating SNMP GETs might support specifying either the 1195 server's certificate fingerprint or the expected host name as a 1196 command line argument. 1198 5) (D)TLS provides assurance that the authenticated identity has 1199 been signed by a trusted configured certification authority. If 1200 verification of the server's certificate fails in any way (for 1201 example because of failures in cryptographic verification or the 1202 presented identity did not match the expected named entity) then 1203 the session establishment MUST fail, the 1204 snmpTlstmSessionInvalidServerCertificates object is incremented. 1205 If the session can not be opened for any reason at all, including 1206 cryptographic verification failures and snmpTlstmCertToTSNTable 1207 lookup failures, then the snmpTlstmSessionOpenErrors counter is 1208 incremented and processing stops. 1210 6) The TLSTM-specific session identifier (tlstmSessionID) is set in 1211 the tmSessionID of the tmStateReference passed to the TLS 1212 Transport Model to indicate that the session has been established 1213 successfully and to point to a specific (D)TLS connection for 1214 future use. The tlstmSessionID is also stored in the LCD for 1215 later lookup during processing of incoming messages 1216 (Section 5.1.2). 1218 5.3.2. Accepting a Session as a Server 1220 A (D)TLS server should accept new session connections from any client 1221 that it is able to verify the client's credentials for. This is done 1222 by authenticating the client's presented certificate through a 1223 certificate path validation process (e.g. [RFC5280]) or through 1224 certificate fingerprint verification using fingerprints configured in 1225 the snmpTlstmCertToTSNTable. Afterward the server will determine the 1226 identity of the remote entity using the following procedures. 1228 The (D)TLS server identifies the authenticated identity from the 1229 (D)TLS client's principal certificate using configuration information 1230 from the snmpTlstmCertToTSNTable mapping table. The (D)TLS server 1231 MUST request and expect a certificate from the client and MUST NOT 1232 accept SNMP messages over the (D)TLS connection until the client has 1233 sent a certificate and it has been authenticated. The resulting 1234 derived tmSecurityName is recorded in the tmStateReference cache as 1235 tmSecurityName. The details of the lookup process are fully 1236 described in the DESCRIPTION clause of the snmpTlstmCertToTSNTable 1237 MIB object. If any verification fails in any way (for example 1238 because of failures in cryptographic verification or because of the 1239 lack of an appropriate row in the snmpTlstmCertToTSNTable) then the 1240 session establishment MUST fail, and the 1241 snmpTlstmSessionInvalidClientCertificates object is incremented. If 1242 the session can not be opened for any reason at all, including 1243 cryptographic verification failures, then the 1244 snmpTlstmSessionOpenErrors counter is incremented and processing 1245 stops. 1247 Servers that wish to support multiple principals at a particular port 1248 SHOULD make use of a (D)TLS extension that allows server-side 1249 principal selection like the Server Name Indication extension defined 1250 in Section 3.1 of [RFC4366]. Supporting this will allow, for 1251 example, sending notifications to a specific principal at a given TCP 1252 or UDP port. 1254 5.4. Closing a Session 1256 The TLS Transport Model provides the following primitive to close a 1257 session: 1259 statusInformation = 1260 closeSession( 1261 IN tmSessionID -- session ID of the session to be closed 1262 ) 1264 The following describes the procedure to follow to close a session 1265 between a client and server. This process is followed by any SNMP 1266 engine closing the corresponding SNMP session. 1268 1) Increment either the snmpTlstmSessionClientCloses or the 1269 snmpTlstmSessionServerCloses counter as appropriate. 1271 2) Look up the session using the tmSessionID. 1273 3) If there is no open session associated with the tmSessionID, then 1274 closeSession processing is completed. 1276 4) Have (D)TLS close the specified connection. This MUST include 1277 sending a close_notify TLS Alert to inform the other side that 1278 session cleanup may be performed. 1280 6. MIB Module Overview 1282 This MIB module provides management of the TLS Transport Model. It 1283 defines needed textual conventions, statistical counters, 1284 notifications and configuration infrastructure necessary for session 1285 establishment. Example usage of the configuration tables can be 1286 found in Appendix A. 1288 6.1. Structure of the MIB Module 1290 Objects in this MIB module are arranged into subtrees. Each subtree 1291 is organized as a set of related objects. The overall structure and 1292 assignment of objects to their subtrees, and the intended purpose of 1293 each subtree, is shown below. 1295 6.2. Textual Conventions 1297 Generic and Common Textual Conventions used in this module can be 1298 found summarized at http://www.ops.ietf.org/mib-common-tcs.html 1300 This module defines the following new Textual Conventions: 1302 o A new TransportAddress format for describing (D)TLS connection 1303 addressing requirements. 1305 o A certificate fingerprint allowing MIB module objects to 1306 generically refer to a stored X.509 certificate using a 1307 cryptographic hash as a reference pointer. 1309 6.3. Statistical Counters 1311 The SNMP-TLS-TM-MIB defines counters that provide network management 1312 stations with information about session usage and potential errors 1313 that a device may be experiencing. 1315 6.4. Configuration Tables 1317 The SNMP-TLS-TM-MIB defines configuration tables that an 1318 administrator can use for configuring a device for sending and 1319 receiving SNMP messages over (D)TLS. In particular, there are MIB 1320 tables that extend the SNMP-TARGET-MIB for configuring (D)TLS 1321 certificate usage and a MIB table for mapping incoming (D)TLS client 1322 certificates to SNMPv3 securityNames. 1324 6.4.1. Notifications 1326 The SNMP-TLS-TM-MIB defines notifications to alert management 1327 stations when a (D)TLS connection fails because a server's presented 1328 certificate did not meet an expected value 1329 (snmpTlstmServerCertificateUnknown) or because cryptographic 1330 validation failed (snmpTlstmServerInvalidCertificate). 1332 6.5. Relationship to Other MIB Modules 1334 Some management objects defined in other MIB modules are applicable 1335 to an entity implementing the TLS Transport Model. In particular, it 1336 is assumed that an entity implementing the SNMP-TLS-TM-MIB will 1337 implement the SNMPv2-MIB [RFC3418], the SNMP-FRAMEWORK-MIB [RFC3411], 1338 the SNMP-TARGET-MIB [RFC3413], the SNMP-NOTIFICATION-MIB [RFC3413] 1339 and the SNMP-VIEW-BASED-ACM-MIB [RFC3415]. 1341 The SNMP-TLS-TM-MIB module contained in this document is for managing 1342 TLS Transport Model information. 1344 6.5.1. MIB Modules Required for IMPORTS 1346 The SNMP-TLS-TM-MIB module imports items from SNMPv2-SMI [RFC2578], 1347 SNMPv2-TC [RFC2579], SNMP-FRAMEWORK-MIB [RFC3411], SNMP-TARGET-MIB 1348 [RFC3413] and SNMPv2-CONF [RFC2580]. 1350 7. MIB Module Definition 1352 SNMP-TLS-TM-MIB DEFINITIONS ::= BEGIN 1354 IMPORTS 1355 MODULE-IDENTITY, OBJECT-TYPE, 1356 OBJECT-IDENTITY, mib-2, snmpDomains, 1357 Counter32, Unsigned32, Gauge32, NOTIFICATION-TYPE 1358 FROM SNMPv2-SMI -- RFC2578 or any update thereof 1359 TEXTUAL-CONVENTION, TimeStamp, RowStatus, StorageType, 1360 AutonomousType 1361 FROM SNMPv2-TC -- RFC2579 or any update thereof 1362 MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP 1363 FROM SNMPv2-CONF -- RFC2580 or any update thereof 1364 SnmpAdminString 1365 FROM SNMP-FRAMEWORK-MIB -- RFC3411 or any update thereof 1366 snmpTargetParamsName, snmpTargetAddrName 1367 FROM SNMP-TARGET-MIB -- RFC3413 or any update thereof 1368 ; 1370 snmpTlstmMIB MODULE-IDENTITY 1371 LAST-UPDATED "201005070000Z" 1372 ORGANIZATION "ISMS Working Group" 1373 CONTACT-INFO "WG-EMail: isms@lists.ietf.org 1374 Subscribe: isms-request@lists.ietf.org 1376 Chairs: 1377 Juergen Schoenwaelder 1378 Jacobs University Bremen 1379 Campus Ring 1 1380 28725 Bremen 1381 Germany 1382 +49 421 200-3587 1383 j.schoenwaelder@jacobs-university.de 1385 Russ Mundy 1386 SPARTA, Inc. 1387 7110 Samuel Morse Drive 1388 Columbia, MD 21046 1389 USA 1391 Editor: 1392 Wes Hardaker 1393 Sparta, Inc. 1394 P.O. Box 382 1395 Davis, CA 95617 1396 USA 1397 ietf@hardakers.net 1398 " 1400 DESCRIPTION " 1401 The TLS Transport Model MIB 1403 Copyright (c) 2010 IETF Trust and the persons identified as 1404 the document authors. All rights reserved. 1406 Redistribution and use in source and binary forms, with or 1407 without modification, is permitted pursuant to, and subject 1408 to the license terms contained in, the Simplified BSD License 1409 set forth in Section 4.c of the IETF Trust's Legal Provisions 1410 Relating to IETF Documents 1411 (http://trustee.ietf.org/license-info)." 1413 REVISION "201005070000Z" 1414 DESCRIPTION "This version of this MIB module is part of 1415 RFC XXXX; see the RFC itself for full legal 1416 notices." 1418 -- NOTE to RFC editor: replace XXXX with actual RFC number 1419 -- for this document and change the date to the 1420 -- current date and remove this note 1422 ::= { mib-2 www } 1423 -- RFC Ed.: replace www with IANA-assigned number under the mib-2 1424 -- SNMP OID tree and remove this note 1426 -- ************************************************ 1427 -- subtrees of the SNMP-TLS-TM-MIB 1428 -- ************************************************ 1429 snmpTlstmNotifications OBJECT IDENTIFIER ::= { snmpTlstmMIB 0 } 1430 snmpTlstmIdentities OBJECT IDENTIFIER ::= { snmpTlstmMIB 1 } 1431 snmpTlstmObjects OBJECT IDENTIFIER ::= { snmpTlstmMIB 2 } 1432 snmpTlstmConformance OBJECT IDENTIFIER ::= { snmpTlstmMIB 3 } 1434 -- ************************************************ 1435 -- snmpTlstmObjects - Objects 1436 -- ************************************************ 1438 snmpTLSTCPDomain OBJECT-IDENTITY 1439 STATUS current 1440 DESCRIPTION 1441 "The SNMP over TLS transport domain. The corresponding 1442 transport address is of type SnmpTLSAddress. 1444 The securityName prefix to be associated with the 1445 snmpTLSTCPDomain is 'tls'. This prefix may be used by 1446 security models or other components to identify which secure 1447 transport infrastructure authenticated a securityName." 1448 REFERENCE 1449 "RFC 2579: Textual Conventions for SMIv2" 1451 ::= { snmpDomains xx } 1453 -- RFC Ed.: replace xx with IANA-assigned number and 1454 -- remove this note 1456 -- RFC Ed.: replace 'tls' with the actual IANA assigned prefix string 1457 -- if 'tls' is not assigned to this document. 1459 snmpDTLSUDPDomain OBJECT-IDENTITY 1460 STATUS current 1461 DESCRIPTION 1462 "The SNMP over DTLS/UDP transport domain. The corresponding 1463 transport address is of type SnmpTLSAddress. 1465 The securityName prefix to be associated with the 1466 snmpDTLSUDPDomain is 'dtls'. This prefix may be used by 1467 security models or other components to identify which secure 1468 transport infrastructure authenticated a securityName." 1469 REFERENCE 1470 "RFC 2579: Textual Conventions for SMIv2" 1472 ::= { snmpDomains yy } 1474 -- RFC Ed.: replace yy with IANA-assigned number and 1475 -- remove this note 1477 -- RFC Ed.: replace 'dtls' with the actual IANA assigned prefix string 1478 -- if 'dtls' is not assigned to this document. 1480 SnmpTLSAddress ::= TEXTUAL-CONVENTION 1481 DISPLAY-HINT "1a" 1482 STATUS current 1483 DESCRIPTION 1484 "Represents a IPv4 address, an IPv6 address or an US-ASCII 1485 encoded hostname and port number. 1487 An IPv4 address must be in dotted decimal format followed by a 1488 colon ':' (US-ASCII character 0x3A) and a decimal port number 1489 in US-ASCII. 1491 An IPv6 address must be a colon separated format (as described 1492 in I-D.ietf-6man-text-addr-representation), surrounded by 1493 square brackets ('[', US-ASCII character 0x5B, and ']', 1494 US-ASCII character 0x5D), followed by a colon ':' (US-ASCII 1495 character 0x3A) and a decimal port number in US-ASCII. 1497 A hostname is always in US-ASCII (as per RFC1033); 1498 internationalized hostnames are encoded in US-ASCII as domain 1499 names after transformation via the ToASCII operation specified 1500 in RFC 3490. The ToASCII operation MUST be performed with the 1501 UseSTD3ASCIIRules flag set. The hostname is followed by a 1502 colon ':' (US-ASCII character 0x3A) and a decimal port number 1503 in US-ASCII. The name SHOULD be fully qualified whenever 1504 possible. 1506 Values of this textual convention may not be directly usable 1507 as transport-layer addressing information, and may require 1508 run-time resolution. As such, applications that write them 1509 must be prepared for handling errors if such values are not 1510 supported, or cannot be resolved (if resolution occurs at the 1511 time of the management operation). 1513 The DESCRIPTION clause of TransportAddress objects that may 1514 have SnmpTLSAddress values must fully describe how (and 1515 when) such names are to be resolved to IP addresses and vice 1516 versa. 1518 This textual convention SHOULD NOT be used directly in object 1519 definitions since it restricts addresses to a specific 1520 format. However, if it is used, it MAY be used either on its 1521 own or in conjunction with TransportAddressType or 1522 TransportDomain as a pair. 1524 When this textual convention is used as a syntax of an index 1525 object, there may be issues with the limit of 128 1526 sub-identifiers specified in SMIv2 (STD 58). It is RECOMMENDED 1527 that all MIB documents using this textual convention make 1528 explicit any limitations on index component lengths that 1529 management software must observe. This may be done either by 1530 including SIZE constraints on the index components or by 1531 specifying applicable constraints in the conceptual row 1532 DESCRIPTION clause or in the surrounding documentation." 1533 REFERENCE 1534 "RFC 1033: DOMAIN ADMINISTRATORS OPERATIONS GUIDE 1535 RFC 3490: Internationalizing Domain Names in Applications 1536 I-D.ietf-6man-text-addr-representation: 1537 A Recommendation for IPv6 Address Text Representation 1538 " 1539 SYNTAX OCTET STRING (SIZE (1..255)) 1541 -- RFC Editor: if I-D.ietf-6man-text-addr-representation fails to get 1542 -- published then replace the reference to 1543 -- I-D.ietf-6man-text-addr-representation with a reference to 1544 -- "RFC3513: Internet Protocol Version 6 (IPv6) Addressing Architecture" 1545 -- instead. 1547 SnmpTLSFingerprint ::= TEXTUAL-CONVENTION 1548 DISPLAY-HINT "1x:254x" 1549 STATUS current 1550 DESCRIPTION 1551 "A fingerprint value that can be used to uniquely reference 1552 other data of potentially arbitrary length. 1554 A SnmpTLSFingerprint value is composed of a 1-octet hashing 1555 algorithm identifier followed by the fingerprint value. The 1556 octet value encoded is taken from the IANA TLS HashAlgorithm 1557 Registry (RFC5246). The remaining octets are filled using the 1558 results of the hashing algorithm. 1560 This TEXTUAL-CONVENTION allows for a zero-length (blank) 1561 SnmpTLSFingerprint value for use in tables where the 1562 fingerprint value may be optional. MIB definitions or 1563 implementations may refuse to accept a zero-length value as 1564 appropriate." 1565 REFERENCE "RFC 5246: The Transport Layer 1566 Security (TLS) Protocol Version 1.2 1567 http://www.iana.org/assignments/tls-parameters/ 1568 " 1569 SYNTAX OCTET STRING (SIZE (0..255)) 1571 -- Identities for use in the snmpTlstmCertToTSNTable 1572 snmpTlstmCertToTSNMIdentities OBJECT IDENTIFIER 1573 ::= { snmpTlstmIdentities 1 } 1575 snmpTlstmCertSpecified OBJECT-IDENTITY 1576 STATUS current 1577 DESCRIPTION "Directly specifies the tmSecurityName to be used for 1578 this certificate. The value of the tmSecurityName 1579 to use is specified in the snmpTlstmCertToTSNData 1580 column. The snmpTlstmCertToTSNData column must 1581 contain a non-zero length SnmpAdminString compliant 1582 value or the mapping described in this row must be 1583 considered a failure." 1584 ::= { snmpTlstmCertToTSNMIdentities 1 } 1586 snmpTlstmCertSANRFC822Name OBJECT-IDENTITY 1587 STATUS current 1588 DESCRIPTION "Maps a subjectAltName's rfc822Name to a 1589 tmSecurityName. The local part of the rfc822Name is 1590 passed unaltered but the host-part of the name must 1591 be passed in lower case. This mapping results in a 1592 1:1 correspondence between equivalent subjectAltName 1593 rfc822Name values and tmSecurityName values except 1594 that the host-part of the name MUST be passed in 1595 lower case. 1597 Example rfc822Name Field: FooBar@Example.COM 1598 is mapped to tmSecurityName: FooBar@example.com" 1599 ::= { snmpTlstmCertToTSNMIdentities 2 } 1601 snmpTlstmCertSANDNSName OBJECT-IDENTITY 1602 STATUS current 1603 DESCRIPTION "Maps a subjectAltName's dNSName to a 1604 tmSecurityName after first converting it to all 1605 lower case (RFC5280 does not specify converting to 1606 lower case so this involves an extra step). This 1607 mapping results in a 1:1 correspondence between 1608 subjectAltName dNSName values and the tmSecurityName 1609 values." 1610 REFERENCE "RFC5280 - Internet X.509 Public Key Infrastructure 1611 Certificate and Certificate Revocation 1612 List (CRL) Profile" 1613 ::= { snmpTlstmCertToTSNMIdentities 3 } 1615 snmpTlstmCertSANIpAddress OBJECT-IDENTITY 1616 STATUS current 1617 DESCRIPTION "Maps a subjectAltName's iPAddress to a 1618 tmSecurityName by transforming the binary encoded 1619 address as follows: 1621 1) for IPv4 the value is converted into a decimal 1622 dotted quad address (e.g. '192.0.2.1') 1624 2) for IPv6 addresses the value is converted into a 1625 32-character all lowercase hexadecimal string 1626 without any colon separators. 1628 This mapping results in a 1:1 correspondence between 1629 subjectAltName iPAddress values and the 1630 tmSecurityName values. 1632 The resulting length is the maximum length supported 1633 by the View-Based Access Control Model (VACM). 1634 Using both the Transport Security Model's support 1635 for transport prefixes (see the SNMP-TSM-MIB's 1636 snmpTsmConfigurationUsePrefix object for details) 1637 will result in securityName lengths that exceed what 1638 VACM can handle." 1639 ::= { snmpTlstmCertToTSNMIdentities 4 } 1641 snmpTlstmCertSANAny OBJECT-IDENTITY 1642 STATUS current 1643 DESCRIPTION "Maps any of the following fields using the 1644 corresponding mapping algorithms: 1646 |------------+----------------------------| 1647 | Type | Algorithm | 1648 |------------+----------------------------| 1649 | rfc822Name | snmpTlstmCertSANRFC822Name | 1650 | dNSName | snmpTlstmCertSANDNSName | 1651 | iPAddress | snmpTlstmCertSANIpAddress | 1652 |------------+----------------------------| 1654 The first matching subjectAltName value found in the 1655 certificate of the above types MUST be used when 1656 deriving the tmSecurityName. The mapping algorithm 1657 specified in the 'Algorithm' column MUST be used to 1658 derive the tmSecurityName. 1660 This mapping results in a 1:1 correspondence between 1661 subjectAltName values and tmSecurityName values. The 1662 three sub-mapping algorithms produced by this 1663 combined algorithm cannot produce conflicting 1664 results between themselves." 1665 ::= { snmpTlstmCertToTSNMIdentities 5 } 1667 snmpTlstmCertCommonName OBJECT-IDENTITY 1668 STATUS current 1669 DESCRIPTION "Maps a certificate's CommonName to a tmSecurityName 1670 after converting it to a UTF-8 encoding. The usage 1671 of CommonNames is deprecated and users are 1672 encouraged to use subjectAltName mapping methods 1673 instead. This mapping results in a 1:1 1674 correspondence between certificate CommonName values 1675 and tmSecurityName values." 1676 ::= { snmpTlstmCertToTSNMIdentities 6 } 1678 -- The snmpTlstmSession Group 1680 snmpTlstmSession OBJECT IDENTIFIER ::= { snmpTlstmObjects 1 } 1682 snmpTlstmSessionOpens OBJECT-TYPE 1683 SYNTAX Counter32 1684 MAX-ACCESS read-only 1685 STATUS current 1686 DESCRIPTION 1687 "The number of times an openSession() request has been executed 1688 as an (D)TLS client, regardless of whether it succeeded or 1689 failed." 1690 ::= { snmpTlstmSession 1 } 1692 snmpTlstmSessionClientCloses OBJECT-TYPE 1693 SYNTAX Counter32 1694 MAX-ACCESS read-only 1695 STATUS current 1696 DESCRIPTION 1697 "The number of times a closeSession() request has been 1698 executed as an (D)TLS client, regardless of whether it 1699 succeeded or failed." 1700 ::= { snmpTlstmSession 2 } 1702 snmpTlstmSessionOpenErrors OBJECT-TYPE 1703 SYNTAX Counter32 1704 MAX-ACCESS read-only 1705 STATUS current 1706 DESCRIPTION 1707 "The number of times an openSession() request failed to open a 1708 session as a (D)TLS client, for any reason." 1709 ::= { snmpTlstmSession 3 } 1711 snmpTlstmSessionAccepts OBJECT-TYPE 1712 SYNTAX Counter32 1713 MAX-ACCESS read-only 1714 STATUS current 1715 DESCRIPTION 1716 "The number of times a (D)TLS server has accepted a new 1717 connection from a client and has received at least one SNMP 1718 message through it." 1719 ::= { snmpTlstmSession 4 } 1721 snmpTlstmSessionServerCloses OBJECT-TYPE 1722 SYNTAX Counter32 1723 MAX-ACCESS read-only 1724 STATUS current 1725 DESCRIPTION 1726 "The number of times a closeSession() request has been 1727 executed as an (D)TLS server, regardless of whether it 1728 succeeded or failed." 1729 ::= { snmpTlstmSession 5 } 1731 snmpTlstmSessionNoSessions OBJECT-TYPE 1732 SYNTAX Counter32 1733 MAX-ACCESS read-only 1734 STATUS current 1735 DESCRIPTION 1736 "The number of times an outgoing message was dropped because 1737 the session associated with the passed tmStateReference was no 1738 longer (or was never) available." 1739 ::= { snmpTlstmSession 6 } 1741 snmpTlstmSessionInvalidClientCertificates OBJECT-TYPE 1742 SYNTAX Counter32 1743 MAX-ACCESS read-only 1744 STATUS current 1745 DESCRIPTION 1746 "The number of times an incoming session was not established 1747 on an (D)TLS server because the presented client certificate 1748 was invalid. Reasons for invalidation include, but are not 1749 limited to, cryptographic validation failures or lack of a 1750 suitable mapping row in the snmpTlstmCertToTSNTable." 1751 ::= { snmpTlstmSession 7 } 1753 snmpTlstmSessionUnknownServerCertificate OBJECT-TYPE 1754 SYNTAX Counter32 1755 MAX-ACCESS read-only 1756 STATUS current 1757 DESCRIPTION 1758 "The number of times an outgoing session was not established 1759 on an (D)TLS client because the server certificate presented 1760 by a SNMP over (D)TLS server was invalid because no 1761 configured fingerprint or CA was acceptable to validate it. 1762 This may result because there was no entry in the 1763 snmpTlstmAddrTable or because no path could be found to a 1764 known certification authority." 1766 ::= { snmpTlstmSession 8 } 1768 snmpTlstmSessionInvalidServerCertificates OBJECT-TYPE 1769 SYNTAX Counter32 1770 MAX-ACCESS read-only 1771 STATUS current 1772 DESCRIPTION 1773 "The number of times an outgoing session was not established 1774 on an (D)TLS client because the server certificate presented 1775 by an SNMP over (D)TLS server could not be validated even if 1776 the fingerprint or expected validation path was known. I.E., 1777 a cryptographic validation error occurred during certificate 1778 validation processing. 1780 Reasons for invalidation include, but are not 1781 limited to, cryptographic validation failures." 1782 ::= { snmpTlstmSession 9 } 1784 snmpTlstmSessionInvalidCaches OBJECT-TYPE 1785 SYNTAX Counter32 1786 MAX-ACCESS read-only 1787 STATUS current 1788 DESCRIPTION 1789 "The number of outgoing messages dropped because the 1790 tmStateReference referred to an invalid cache." 1791 ::= { snmpTlstmSession 10 } 1793 -- Configuration Objects 1795 snmpTlstmConfig OBJECT IDENTIFIER ::= { snmpTlstmObjects 2 } 1797 -- Certificate mapping 1799 snmpTlstmCertificateMapping OBJECT IDENTIFIER ::= { snmpTlstmConfig 1 } 1801 snmpTlstmCertToTSNCount OBJECT-TYPE 1802 SYNTAX Gauge32 1803 MAX-ACCESS read-only 1804 STATUS current 1805 DESCRIPTION 1806 "A count of the number of entries in the 1807 snmpTlstmCertToTSNTable" 1808 ::= { snmpTlstmCertificateMapping 1 } 1810 snmpTlstmCertToTSNTableLastChanged OBJECT-TYPE 1811 SYNTAX TimeStamp 1812 MAX-ACCESS read-only 1813 STATUS current 1814 DESCRIPTION 1815 "The value of sysUpTime.0 when the snmpTlstmCertToTSNTable was 1816 last modified through any means, or 0 if it has not been 1817 modified since the command responder was started." 1818 ::= { snmpTlstmCertificateMapping 2 } 1820 snmpTlstmCertToTSNTable OBJECT-TYPE 1821 SYNTAX SEQUENCE OF SnmpTlstmCertToTSNEntry 1822 MAX-ACCESS not-accessible 1823 STATUS current 1824 DESCRIPTION 1825 "This table is used by a (D)TLS server to map the (D)TLS 1826 client's presented X.509 certificate to a tmSecurityName. 1828 On an incoming (D)TLS/SNMP connection the client's presented 1829 certificate must either be validated based on an established 1830 trust anchor, or it must directly match a fingerprint in this 1831 table. This table does not provide any mechanisms for 1832 configuring the trust anchors; the transfer of any needed 1833 trusted certificates for path validation is expected to occur 1834 through an out-of-band transfer. 1836 Once the certificate has been found acceptable (either by path 1837 validation or directly matching a fingerprint in this table), 1838 this table is consulted to determine the appropriate 1839 tmSecurityName to identify with the remote connection. This 1840 is done by considering each active row from this table in 1841 prioritized order according to its snmpTlstmCertToTSNID value. 1842 Each row's snmpTlstmCertToTSNFingerprint value determines 1843 whether the row is a match for the incoming connection: 1845 1) If the row's snmpTlstmCertToTSNFingerprint value 1846 identifies the presented certificate then consider the 1847 row as a successful match. 1849 2) If the row's snmpTlstmCertToTSNFingerprint value 1850 identifies a locally held copy of a trusted CA 1851 certificate and that CA certificate was used to 1852 validate the path to the presented certificate then 1853 consider the row as a successful match. 1855 Once a matching row has been found, the 1856 snmpTlstmCertToTSNMapType value can be used to determine how 1857 the tmSecurityName to associate with the session should be 1858 determined. See the snmpTlstmCertToTSNMapType column's 1859 DESCRIPTION for details on determining the tmSecurityName 1860 value. If it is impossible to determine a tmSecurityName from 1861 the row's data combined with the data presented in the 1862 certificate then additional rows MUST be searched looking for 1863 another potential match. If a resulting tmSecurityName mapped 1864 from a given row is not compatible with the needed 1865 requirements of a tmSecurityName (e.g., VACM imposes a 1866 32-octet-maximum length and the certificate derived 1867 securityName could be longer) then it must be considered an 1868 invalid match and additional rows MUST be searched looking for 1869 another potential match. 1871 If no matching and valid row can be found, the connection MUST 1872 be closed and SNMP messages MUST NOT be accepted over it. 1874 Missing values of snmpTlstmCertToTSNID are acceptable and 1875 implementations should continue to the next highest numbered 1876 row. It is recommended that administrators skip index values 1877 to leave room for the insertion of future rows (E.G., use values 1878 of 10 and 20 when creating initial rows). 1880 Users are encouraged to make use of certificates with 1881 subjectAltName fields that can be used as tmSecurityNames so 1882 that a single root CA certificate can allow all child 1883 certificate's subjectAltName to map directly to a 1884 tmSecurityName via a 1:1 transformation. However, this table 1885 is flexible to allow for situations where existing deployed 1886 certificate infrastructures do not provide adequate 1887 subjectAltName values for use as tmSecurityNames. 1888 Certificates may also be mapped to tmSecurityNames using the 1889 CommonName portion of the Subject field. However, the usage 1890 of the CommonName field is deprecated and thus this usage is 1891 NOT RECOMMENDED. Direct mapping from each individual 1892 certificate fingerprint to a tmSecurityName is also possible 1893 but requires one entry in the table per tmSecurityName and 1894 requires more management operations to completely configure a 1895 device." 1896 ::= { snmpTlstmCertificateMapping 3 } 1898 snmpTlstmCertToTSNEntry OBJECT-TYPE 1899 SYNTAX SnmpTlstmCertToTSNEntry 1900 MAX-ACCESS not-accessible 1901 STATUS current 1902 DESCRIPTION 1903 "A row in the snmpTlstmCertToTSNTable that specifies a mapping 1904 for an incoming (D)TLS certificate to a tmSecurityName to use 1905 for a connection." 1906 INDEX { snmpTlstmCertToTSNID } 1907 ::= { snmpTlstmCertToTSNTable 1 } 1909 SnmpTlstmCertToTSNEntry ::= SEQUENCE { 1910 snmpTlstmCertToTSNID Unsigned32, 1911 snmpTlstmCertToTSNFingerprint SnmpTLSFingerprint, 1912 snmpTlstmCertToTSNMapType AutonomousType, 1913 snmpTlstmCertToTSNData OCTET STRING, 1914 snmpTlstmCertToTSNStorageType StorageType, 1915 snmpTlstmCertToTSNRowStatus RowStatus 1916 } 1918 snmpTlstmCertToTSNID OBJECT-TYPE 1919 SYNTAX Unsigned32 (1..4294967295) 1920 MAX-ACCESS not-accessible 1921 STATUS current 1922 DESCRIPTION 1923 "A unique, prioritized index for the given entry. Lower 1924 numbers indicate a higher priority." 1925 ::= { snmpTlstmCertToTSNEntry 1 } 1927 snmpTlstmCertToTSNFingerprint OBJECT-TYPE 1928 SYNTAX SnmpTLSFingerprint (SIZE(1..255)) 1929 MAX-ACCESS read-create 1930 STATUS current 1931 DESCRIPTION 1932 "A cryptographic hash of a X.509 certificate. The results of 1933 a successful matching fingerprint to either the trusted CA in 1934 the certificate validation path or to the certificate itself 1935 is dictated by the snmpTlstmCertToTSNMapType column." 1936 ::= { snmpTlstmCertToTSNEntry 2 } 1938 snmpTlstmCertToTSNMapType OBJECT-TYPE 1939 SYNTAX AutonomousType 1940 MAX-ACCESS read-create 1941 STATUS current 1942 DESCRIPTION 1943 "Specifies the mapping type for deriving a tmSecurityName from 1944 a certificate. Details for mapping of a particular type SHALL 1945 be specified in the DESCRIPTION clause of the OBJECT-IDENTITY 1946 that describes the mapping. If a mapping succeeds it will 1947 return a tmSecurityName for use by the TLSTM model and 1948 processing stops. 1950 If the resulting mapped value is not compatible with the 1951 needed requirements of a tmSecurityName (e.g., VACM imposes a 1952 32-octet-maximum length and the certificate derived 1953 securityName could be longer) then future rows MUST be 1954 searched for additional snmpTlstmCertToTSNFingerprint matches 1955 to look for a mapping that succeeds. 1957 Suitable values for assigning to this object that are defined 1958 within the SNMP-TLS-TM-MIB can be found in the 1959 snmpTlstmCertToTSNMIdentities portion of the MIB tree." 1960 DEFVAL { snmpTlstmCertSpecified } 1961 ::= { snmpTlstmCertToTSNEntry 3 } 1963 snmpTlstmCertToTSNData OBJECT-TYPE 1964 SYNTAX OCTET STRING (SIZE(0..1024)) 1965 MAX-ACCESS read-create 1966 STATUS current 1967 DESCRIPTION 1968 "Auxiliary data used as optional configuration information for 1969 a given mapping specified by the snmpTlstmCertToTSNMapType 1970 column. Only some mapping systems will make use of this 1971 column. The value in this column MUST be ignored for any 1972 mapping type that does not require data present in this 1973 column." 1974 DEFVAL { "" } 1975 ::= { snmpTlstmCertToTSNEntry 4 } 1977 snmpTlstmCertToTSNStorageType OBJECT-TYPE 1978 SYNTAX StorageType 1979 MAX-ACCESS read-create 1980 STATUS current 1981 DESCRIPTION 1982 "The storage type for this conceptual row. Conceptual rows 1983 having the value 'permanent' need not allow write-access to 1984 any columnar objects in the row." 1985 DEFVAL { nonVolatile } 1986 ::= { snmpTlstmCertToTSNEntry 5 } 1988 snmpTlstmCertToTSNRowStatus OBJECT-TYPE 1989 SYNTAX RowStatus 1990 MAX-ACCESS read-create 1991 STATUS current 1992 DESCRIPTION 1993 "The status of this conceptual row. This object may be used 1994 to create or remove rows from this table. 1996 To create a row in this table, an administrator must set this 1997 object to either createAndGo(4) or createAndWait(5). 1999 Until instances of all corresponding columns are appropriately 2000 configured, the value of the corresponding instance of the 2001 snmpTlstmParamsRowStatus column is notReady(3). 2003 In particular, a newly created row cannot be made active until 2004 the corresponding snmpTlstmCertToTSNFingerprint, 2005 snmpTlstmCertToTSNMapType, and snmpTlstmCertToTSNData columns 2006 have been set. 2008 The following objects may not be modified while the 2009 value of this object is active(1): 2010 - snmpTlstmCertToTSNFingerprint 2011 - snmpTlstmCertToTSNMapType 2012 - snmpTlstmCertToTSNData 2013 An attempt to set these objects while the value of 2014 snmpTlstmParamsRowStatus is active(1) will result in 2015 an inconsistentValue error." 2016 ::= { snmpTlstmCertToTSNEntry 6 } 2018 -- Maps tmSecurityNames to certificates for use by the SNMP-TARGET-MIB 2020 snmpTlstmParamsCount OBJECT-TYPE 2021 SYNTAX Gauge32 2022 MAX-ACCESS read-only 2023 STATUS current 2024 DESCRIPTION 2025 "A count of the number of entries in the snmpTlstmParamsTable" 2026 ::= { snmpTlstmCertificateMapping 4 } 2028 snmpTlstmParamsTableLastChanged OBJECT-TYPE 2029 SYNTAX TimeStamp 2030 MAX-ACCESS read-only 2031 STATUS current 2032 DESCRIPTION 2033 "The value of sysUpTime.0 when the snmpTlstmParamsTable 2034 was last modified through any means, or 0 if it has not been 2035 modified since the command responder was started." 2036 ::= { snmpTlstmCertificateMapping 5 } 2038 snmpTlstmParamsTable OBJECT-TYPE 2039 SYNTAX SEQUENCE OF SnmpTlstmParamsEntry 2040 MAX-ACCESS not-accessible 2041 STATUS current 2042 DESCRIPTION 2043 "This table is used by a (D)TLS client when a (D)TLS 2044 connection is being set up using an entry in the 2045 SNMP-TARGET-MIB. It extends the SNMP-TARGET-MIB's 2046 snmpTargetParamsTable with a fingerprint of a certificate to 2047 use when establishing such a (D)TLS connection." 2048 ::= { snmpTlstmCertificateMapping 6 } 2050 snmpTlstmParamsEntry OBJECT-TYPE 2051 SYNTAX SnmpTlstmParamsEntry 2052 MAX-ACCESS not-accessible 2053 STATUS current 2054 DESCRIPTION 2055 "A conceptual row containing a fingerprint hash of a locally 2056 held certificate for a given snmpTargetParamsEntry. The 2057 values in this row should be ignored if the connection that 2058 needs to be established, as indicated by the SNMP-TARGET-MIB 2059 infrastructure, is not a certificate and (D)TLS based 2060 connection. The connection SHOULD NOT be established if the 2061 certificate fingerprint stored in this entry does not point to 2062 a valid locally held certificate or if it points to an 2063 unusable certificate (such as might happen when the 2064 certificate's expiration date has been reached)." 2065 INDEX { IMPLIED snmpTargetParamsName } 2066 ::= { snmpTlstmParamsTable 1 } 2068 SnmpTlstmParamsEntry ::= SEQUENCE { 2069 snmpTlstmParamsClientFingerprint SnmpTLSFingerprint, 2070 snmpTlstmParamsStorageType StorageType, 2071 snmpTlstmParamsRowStatus RowStatus 2072 } 2074 snmpTlstmParamsClientFingerprint OBJECT-TYPE 2075 SYNTAX SnmpTLSFingerprint 2076 MAX-ACCESS read-create 2077 STATUS current 2078 DESCRIPTION 2079 "This object stores the hash of the public portion of a 2080 locally held X.509 certificate. The X.509 certificate, its 2081 public key, and the corresponding private key will be used 2082 when initiating a (D)TLS connection as a (D)TLS client." 2083 ::= { snmpTlstmParamsEntry 1 } 2085 snmpTlstmParamsStorageType OBJECT-TYPE 2086 SYNTAX StorageType 2087 MAX-ACCESS read-create 2088 STATUS current 2089 DESCRIPTION 2090 "The storage type for this conceptual row. Conceptual rows 2091 having the value 'permanent' need not allow write-access to 2092 any columnar objects in the row." 2093 DEFVAL { nonVolatile } 2094 ::= { snmpTlstmParamsEntry 2 } 2096 snmpTlstmParamsRowStatus OBJECT-TYPE 2097 SYNTAX RowStatus 2098 MAX-ACCESS read-create 2099 STATUS current 2100 DESCRIPTION 2101 "The status of this conceptual row. This object may be used 2102 to create or remove rows from this table. 2104 To create a row in this table, an administrator must set this 2105 object to either createAndGo(4) or createAndWait(5). 2107 Until instances of all corresponding columns are appropriately 2108 configured, the value of the corresponding instance of the 2109 snmpTlstmParamsRowStatus column is notReady(3). 2111 In particular, a newly created row cannot be made active until 2112 the corresponding snmpTlstmParamsClientFingerprint column has 2113 been set. 2115 The snmpTlstmParamsClientFingerprint object may not be modified 2116 while the value of this object is active(1). 2118 An attempt to set these objects while the value of 2119 snmpTlstmParamsRowStatus is active(1) will result in 2120 an inconsistentValue error." 2121 ::= { snmpTlstmParamsEntry 3 } 2123 snmpTlstmAddrCount OBJECT-TYPE 2124 SYNTAX Gauge32 2125 MAX-ACCESS read-only 2126 STATUS current 2127 DESCRIPTION 2128 "A count of the number of entries in the snmpTlstmAddrTable" 2129 ::= { snmpTlstmCertificateMapping 7 } 2131 snmpTlstmAddrTableLastChanged OBJECT-TYPE 2132 SYNTAX TimeStamp 2133 MAX-ACCESS read-only 2134 STATUS current 2135 DESCRIPTION 2136 "The value of sysUpTime.0 when the snmpTlstmAddrTable 2137 was last modified through any means, or 0 if it has not been 2138 modified since the command responder was started." 2139 ::= { snmpTlstmCertificateMapping 8 } 2141 snmpTlstmAddrTable OBJECT-TYPE 2142 SYNTAX SEQUENCE OF SnmpTlstmAddrEntry 2143 MAX-ACCESS not-accessible 2144 STATUS current 2145 DESCRIPTION 2146 "This table is used by a (D)TLS client when a (D)TLS 2147 connection is being set up using an entry in the 2148 SNMP-TARGET-MIB. It extends the SNMP-TARGET-MIB's 2149 snmpTargetAddrTable so that the client can verify that the 2150 correct server has been reached. This verification can use 2151 either a certificate fingerprint, or an identity 2152 authenticated via certification path validation. 2154 If there is an active row in this table corresponding to the 2155 entry in the SNMP-TARGET-MIB that was used to establish the 2156 connection, and the row's snmpTlstmAddrServerFingerprint 2157 column has non-empty value, then the server's presented 2158 certificate is compared with the 2159 snmpTlstmAddrServerFingerprint value (and the 2160 snmpTlstmAddrServerIdentity column is ignored). If the 2161 fingerprint matches, the verification has succeeded. If the 2162 fingerprint does not match then the connection MUST be 2163 closed. 2165 If the server's presented certificate has passed 2166 certification path validation [RFC5280] to a configured 2167 trust anchor, and an active row exists with a zero-length 2168 snmpTlstmAddrServerFingerprint value, then the 2169 snmpTlstmAddrServerIdentity column contains the expected 2170 host name. This expected host name is then compared against 2171 the server's certificate as follows: 2173 - Implementations MUST support matching the expected host 2174 name against a dNSName in the subjectAltName extension 2175 field and MAY support checking the name against the 2176 CommonName portion of the subject distinguished name. 2178 - The '*' (ASCII 0x2a) wildcard character is allowed in the 2179 dNSName of the subjectAltName extension (and in common 2180 name, if used to store the host name), but only as the 2181 left-most (least significant) DNS label in that value. 2182 This wildcard matches any left-most DNS label in the 2183 server name. That is, the subject *.example.com matches 2184 the server names a.example.com and b.example.com, but does 2185 not match example.com or a.b.example.com. Implementations 2186 MUST support wildcards in certificates as specified above, 2187 but MAY provide a configuration option to disable them. 2189 - If the locally configured name is an internationalized 2190 domain name, conforming implementations MUST convert it to 2191 the ASCII Compatible Encoding (ACE) format for performing 2192 comparisons, as specified in Section 7 of [RFC5280]. 2194 If the expected host name fails these conditions then the 2195 connection MUST be closed. 2197 If there is no row in this table corresponding to the entry 2198 in the SNMP-TARGET-MIB and the server can be authorized by 2199 another, implementation dependent means, then the connection 2200 MAY still proceed." 2202 ::= { snmpTlstmCertificateMapping 9 } 2204 snmpTlstmAddrEntry OBJECT-TYPE 2205 SYNTAX SnmpTlstmAddrEntry 2206 MAX-ACCESS not-accessible 2207 STATUS current 2208 DESCRIPTION 2209 "A conceptual row containing a copy of a certificate's 2210 fingerprint for a given snmpTargetAddrEntry. The values in 2211 this row should be ignored if the connection that needs to be 2212 established, as indicated by the SNMP-TARGET-MIB 2213 infrastructure, is not a (D)TLS based connection. If an 2214 snmpTlstmAddrEntry exists for a given snmpTargetAddrEntry then 2215 the presented server certificate MUST match or the connection 2216 MUST NOT be established. If a row in this table does not 2217 exist to match a snmpTargetAddrEntry row then the connection 2218 SHOULD still proceed if some other certificate validation path 2219 algorithm (e.g. RFC5280) can be used." 2220 INDEX { IMPLIED snmpTargetAddrName } 2221 ::= { snmpTlstmAddrTable 1 } 2223 SnmpTlstmAddrEntry ::= SEQUENCE { 2224 snmpTlstmAddrServerFingerprint SnmpTLSFingerprint, 2225 snmpTlstmAddrServerIdentity SnmpAdminString, 2226 snmpTlstmAddrStorageType StorageType, 2227 snmpTlstmAddrRowStatus RowStatus 2228 } 2230 snmpTlstmAddrServerFingerprint OBJECT-TYPE 2231 SYNTAX SnmpTLSFingerprint 2232 MAX-ACCESS read-create 2233 STATUS current 2234 DESCRIPTION 2235 "A cryptographic hash of a public X.509 certificate. This 2236 object should store the hash of the public X.509 certificate 2237 that the remote server should present during the (D)TLS 2238 connection setup. The fingerprint of the presented 2239 certificate and this hash value MUST match exactly or the 2240 connection MUST NOT be established." 2241 DEFVAL { "" } 2242 ::= { snmpTlstmAddrEntry 1 } 2244 snmpTlstmAddrServerIdentity OBJECT-TYPE 2245 SYNTAX SnmpAdminString 2246 MAX-ACCESS read-create 2247 STATUS current 2248 DESCRIPTION 2249 "The reference identity to check against the identity 2250 presented by the remote system." 2251 DEFVAL { "" } 2252 ::= { snmpTlstmAddrEntry 2 } 2254 snmpTlstmAddrStorageType OBJECT-TYPE 2255 SYNTAX StorageType 2256 MAX-ACCESS read-create 2257 STATUS current 2258 DESCRIPTION 2259 "The storage type for this conceptual row. Conceptual rows 2260 having the value 'permanent' need not allow write-access to 2261 any columnar objects in the row." 2262 DEFVAL { nonVolatile } 2263 ::= { snmpTlstmAddrEntry 3 } 2265 snmpTlstmAddrRowStatus OBJECT-TYPE 2266 SYNTAX RowStatus 2267 MAX-ACCESS read-create 2268 STATUS current 2269 DESCRIPTION 2270 "The status of this conceptual row. This object may be used 2271 to create or remove rows from this table. 2273 To create a row in this table, an administrator must set this 2274 object to either createAndGo(4) or createAndWait(5). 2276 Until instances of all corresponding columns are 2277 appropriately configured, the value of the 2278 corresponding instance of the snmpTlstmAddrRowStatus 2279 column is notReady(3). 2281 In particular, a newly created row cannot be made active until 2282 the corresponding snmpTlstmAddrServerFingerprint column has been 2283 set. 2285 Rows MUST NOT be active if the snmpTlstmAddrServerFingerprint 2286 column is blank and the snmpTlstmAddrServerIdentity is set to 2287 '*' since this would insecurely accept any presented 2288 certificate. 2290 The snmpTlstmAddrServerFingerprint object may not be modified 2291 while the value of this object is active(1). 2293 An attempt to set these objects while the value of 2294 snmpTlstmAddrRowStatus is active(1) will result in 2295 an inconsistentValue error." 2296 ::= { snmpTlstmAddrEntry 4 } 2298 -- ************************************************ 2299 -- snmpTlstmNotifications - Notifications Information 2300 -- ************************************************ 2302 snmpTlstmServerCertificateUnknown NOTIFICATION-TYPE 2303 OBJECTS { snmpTlstmSessionUnknownServerCertificate } 2304 STATUS current 2305 DESCRIPTION 2306 "Notification that the server certificate presented by a SNMP 2307 over (D)TLS server was invalid because no configured 2308 fingerprint or CA was acceptable to validate it. This may be 2309 because there was no entry in the snmpTlstmAddrTable or 2310 because no path could be found to known certificate 2311 authority. 2313 To avoid notification loops, this notification MUST NOT be 2314 sent to servers that themselves have triggered the 2315 notification." 2316 ::= { snmpTlstmNotifications 1 } 2318 snmpTlstmServerInvalidCertificate NOTIFICATION-TYPE 2319 OBJECTS { snmpTlstmAddrServerFingerprint, 2320 snmpTlstmSessionInvalidServerCertificates} 2321 STATUS current 2322 DESCRIPTION 2323 "Notification that the server certificate presented by an SNMP 2324 over (D)TLS server could not be validated even if the 2325 fingerprint or expected validation path was known. I.E., a 2326 cryptographic validation error occurred during certificate 2327 validation processing. 2329 To avoid notification loops, this notification MUST NOT be 2330 sent to servers that themselves have triggered the 2331 notification." 2332 ::= { snmpTlstmNotifications 2 } 2334 -- ************************************************ 2335 -- snmpTlstmCompliances - Conformance Information 2336 -- ************************************************ 2338 snmpTlstmCompliances OBJECT IDENTIFIER ::= { snmpTlstmConformance 1 } 2339 snmpTlstmGroups OBJECT IDENTIFIER ::= { snmpTlstmConformance 2 } 2341 -- ************************************************ 2342 -- Compliance statements 2343 -- ************************************************ 2345 snmpTlstmCompliance MODULE-COMPLIANCE 2346 STATUS current 2347 DESCRIPTION 2348 "The compliance statement for SNMP engines that support the 2349 SNMP-TLS-TM-MIB" 2350 MODULE 2351 MANDATORY-GROUPS { snmpTlstmStatsGroup, 2352 snmpTlstmIncomingGroup, 2353 snmpTlstmOutgoingGroup, 2354 snmpTlstmNotificationGroup } 2355 ::= { snmpTlstmCompliances 1 } 2357 -- ************************************************ 2358 -- Units of conformance 2359 -- ************************************************ 2360 snmpTlstmStatsGroup OBJECT-GROUP 2361 OBJECTS { 2362 snmpTlstmSessionOpens, 2363 snmpTlstmSessionClientCloses, 2364 snmpTlstmSessionOpenErrors, 2365 snmpTlstmSessionAccepts, 2366 snmpTlstmSessionServerCloses, 2367 snmpTlstmSessionNoSessions, 2368 snmpTlstmSessionInvalidClientCertificates, 2369 snmpTlstmSessionUnknownServerCertificate, 2370 snmpTlstmSessionInvalidServerCertificates, 2371 snmpTlstmSessionInvalidCaches 2372 } 2373 STATUS current 2374 DESCRIPTION 2375 "A collection of objects for maintaining 2376 statistical information of an SNMP engine which 2377 implements the SNMP TLS Transport Model." 2378 ::= { snmpTlstmGroups 1 } 2380 snmpTlstmIncomingGroup OBJECT-GROUP 2381 OBJECTS { 2382 snmpTlstmCertToTSNCount, 2383 snmpTlstmCertToTSNTableLastChanged, 2384 snmpTlstmCertToTSNFingerprint, 2385 snmpTlstmCertToTSNMapType, 2386 snmpTlstmCertToTSNData, 2387 snmpTlstmCertToTSNStorageType, 2388 snmpTlstmCertToTSNRowStatus 2389 } 2390 STATUS current 2391 DESCRIPTION 2392 "A collection of objects for maintaining 2393 incoming connection certificate mappings to 2394 tmSecurityNames of an SNMP engine which implements the 2395 SNMP TLS Transport Model." 2396 ::= { snmpTlstmGroups 2 } 2398 snmpTlstmOutgoingGroup OBJECT-GROUP 2399 OBJECTS { 2400 snmpTlstmParamsCount, 2401 snmpTlstmParamsTableLastChanged, 2402 snmpTlstmParamsClientFingerprint, 2403 snmpTlstmParamsStorageType, 2404 snmpTlstmParamsRowStatus, 2405 snmpTlstmAddrCount, 2406 snmpTlstmAddrTableLastChanged, 2407 snmpTlstmAddrServerFingerprint, 2408 snmpTlstmAddrServerIdentity, 2409 snmpTlstmAddrStorageType, 2410 snmpTlstmAddrRowStatus 2411 } 2412 STATUS current 2413 DESCRIPTION 2414 "A collection of objects for maintaining 2415 outgoing connection certificates to use when opening 2416 connections as a result of SNMP-TARGET-MIB settings." 2417 ::= { snmpTlstmGroups 3 } 2419 snmpTlstmNotificationGroup NOTIFICATION-GROUP 2420 NOTIFICATIONS { 2421 snmpTlstmServerCertificateUnknown, 2422 snmpTlstmServerInvalidCertificate 2423 } 2424 STATUS current 2425 DESCRIPTION 2426 "Notifications" 2427 ::= { snmpTlstmGroups 4 } 2429 END 2430 8. Operational Considerations 2432 This section discusses various operational aspects of deploying 2433 TLSTM. 2435 8.1. Sessions 2437 A session is discussed throughout this document as meaning a security 2438 association between two TLSTM instances. State information for the 2439 sessions are maintained in each TLSTM implementation and this 2440 information is created and destroyed as sessions are opened and 2441 closed. A "broken" session (one side up and one side down) can 2442 result if one side of a session is brought down abruptly (i.e., 2443 reboot, power outage, etc.). Whenever possible, implementations 2444 SHOULD provide graceful session termination through the use of TLS 2445 disconnect messages. Implementations SHOULD also have a system in 2446 place for detecting "broken" sessions through the use of heartbeats 2447 [I-D.seggelmann-tls-dtls-heartbeat] or other detection mechanisms. 2449 Implementations SHOULD limit the lifetime of established sessions 2450 depending on the algorithms used for generation of the master session 2451 secret, the privacy and integrity algorithms used to protect 2452 messages, the environment of the session, the amount of data 2453 transferred, and the sensitivity of the data. 2455 8.2. Notification Receiver Credential Selection 2457 When an SNMP engine needs to establish an outgoing session for 2458 notifications, the snmpTargetParamsTable includes an entry for the 2459 snmpTargetParamsSecurityName of the target. Servers that wish to 2460 support multiple principals at a particular port SHOULD make use of 2461 the Server Name Indication extension defined in Section 3.1 of 2462 [RFC4366]. Without the Server Name Indication the receiving SNMP 2463 engine (Server) will not know which (D)TLS certificate to offer to 2464 the Client so that the tmSecurityName identity-authentication will be 2465 successful. 2467 Another solution is to maintain a one-to-one mapping between 2468 certificates and incoming ports for notification receivers. This can 2469 be handled at the notification originator by configuring the 2470 snmpTargetAddrTable (snmpTargetAddrTDomain and 2471 snmpTargetAddrTAddress) and requiring the receiving SNMP engine to 2472 monitor multiple incoming static ports based on which principals are 2473 capable of receiving notifications. 2475 Implementations MAY also choose to designate a single Notification 2476 Receiver Principal to receive all incoming notifications or select an 2477 implementation specific method of selecting a server certificate to 2478 present to clients. 2480 8.3. contextEngineID Discovery 2482 SNMPv3 requires that an application know the identifier 2483 (snmpEngineID) of the remote SNMP protocol engine in order to 2484 retrieve or manipulate objects maintained on the remote SNMP entity. 2486 [RFC5343] introduces a well-known localEngineID and a discovery 2487 mechanism that can be used to learn the snmpEngineID of a remote SNMP 2488 protocol engine. Implementations are RECOMMENDED to support and use 2489 the contextEngineID discovery mechanism defined in [RFC5343]. 2491 8.4. Transport Considerations 2493 This document defines how SNMP messages can be transmitted over the 2494 TLS and DTLS based protocols. Each of these protocols are 2495 additionally based on other transports (TCP and UDP). These two base 2496 protocols also have operational considerations that must be taken 2497 into consideration when selecting a (D)TLS based protocol to use such 2498 as its performance in degraded or limited networks. It is beyond the 2499 scope of this document to summarize the characteristics of these 2500 transport mechanisms. Please refer to the base protocol documents 2501 for details on messaging considerations with respect to MTU size, 2502 fragmentation, performance in lossy-networks, etc. 2504 9. Security Considerations 2506 This document describes a transport model that permits SNMP to 2507 utilize (D)TLS security services. The security threats and how the 2508 (D)TLS transport model mitigates these threats are covered in detail 2509 throughout this document. Security considerations for DTLS are 2510 covered in [RFC4347] and security considerations for TLS are 2511 described in Section 11 and Appendices D, E, and F of TLS 1.2 2512 [RFC5246]. When run over a connectionless transport such as UDP, 2513 DTLS is more vulnerable to denial of service attacks from spoofed IP 2514 addresses; see Section 4.2 for details how the cookie exchange is 2515 used to address this issue. 2517 9.1. Certificates, Authentication, and Authorization 2519 Implementations are responsible for providing a security certificate 2520 installation and configuration mechanism. Implementations SHOULD 2521 support certificate revocation lists. 2523 (D)TLS provides for authentication of the identity of both the (D)TLS 2524 server and the (D)TLS client. Access to MIB objects for the 2525 authenticated principal MUST be enforced by an access control 2526 subsystem (e.g. the VACM). 2528 Authentication of the command generator principal's identity is 2529 important for use with the SNMP access control subsystem to ensure 2530 that only authorized principals have access to potentially sensitive 2531 data. The authenticated identity of the command generator 2532 principal's certificate is mapped to an SNMP model-independent 2533 securityName for use with SNMP access control. 2535 The (D)TLS handshake only provides assurance that the certificate of 2536 the authenticated identity has been signed by an configured accepted 2537 certification authority. (D)TLS has no way to further authorize or 2538 reject access based on the authenticated identity. An Access Control 2539 Model (such as the VACM) provides access control and authorization of 2540 a command generator's requests to a command responder and a 2541 notification receiver's authorization to receive Notifications from a 2542 notification originator. However to avoid man-in-the-middle attacks 2543 both ends of the (D)TLS based connection MUST check the certificate 2544 presented by the other side against what was expected. For example, 2545 command generators must check that the command responder presented 2546 and authenticated itself with a X.509 certificate that was expected. 2547 Not doing so would allow an impostor, at a minimum, to present false 2548 data, receive sensitive information and/or provide a false belief 2549 that configuration was actually received and acted upon. 2550 Authenticating and verifying the identity of the (D)TLS server and 2551 the (D)TLS client for all operations ensures the authenticity of the 2552 SNMP engine that provides MIB data. 2554 The instructions found in the DESCRIPTION clause of the 2555 snmpTlstmCertToTSNTable object must be followed exactly. It is also 2556 important that the rows of the table be searched in prioritized order 2557 starting with the row containing the lowest numbered 2558 snmpTlstmCertToTSNID value. 2560 9.2. (D)TLS Security Considerations 2562 This section discusses security considerations specific to the usage 2563 of (D)TLS. 2565 9.2.1. TLS Version Requirements 2567 Implementations of TLS typically support multiple versions of the 2568 Transport Layer Security protocol as well as the older Secure Sockets 2569 Layer (SSL) protocol. Because of known security vulnerabilities, 2570 TLSTM clients and servers MUST NOT request, offer, or use SSL 2.0. 2571 See Appendix E.2 of [RFC5246] for further details. 2573 9.2.2. Perfect Forward Secrecy 2575 The use of Perfect Forward Secrecy is RECOMMENDED and can be provided 2576 by (D)TLS with appropriately selected cipher suites, as discussed in 2577 Appendix F of [RFC5246]. 2579 9.3. Use with SNMPv1/SNMPv2c Messages 2581 The SNMPv1 and SNMPv2c message processing described in [RFC3584] (BCP 2582 74) always selects the SNMPv1 or SNMPv2c Security Models, 2583 respectively. Both of these and the User-based Security Model 2584 typically used with SNMPv3 derive the securityName and securityLevel 2585 from the SNMP message received, even when the message was received 2586 over a secure transport. Access control decisions are therefore made 2587 based on the contents of the SNMP message, rather than using the 2588 authenticated identity and securityLevel provided by the TLS 2589 Transport Model. It is RECOMMENDED that only SNMPv3 messages using 2590 the Transport Security Model (TSM) or another secure-transport aware 2591 security model be sent over the TLSTM transport. 2593 Using a non-transport-aware Security Model with a secure Transport 2594 Model is NOT RECOMMENDED. See [RFC5590] Section 7.1 for additional 2595 details on the coexistence of security-aware transports and non- 2596 transport-aware security models. 2598 9.4. MIB Module Security 2600 There are a number of management objects defined in this MIB module 2601 with a MAX-ACCESS clause of read-write and/or read-create. Such 2602 objects may be considered sensitive or vulnerable in some network 2603 environments. The support for SET operations in a non-secure 2604 environment without proper protection can have a negative effect on 2605 network operations. These are the tables and objects and their 2606 sensitivity/vulnerability: 2608 o The snmpTlstmParamsTable can be used to change the outgoing X.509 2609 certificate used to establish a (D)TLS connection. Modification 2610 to objects in this table need to be adequately authenticated since 2611 modification to values in this table will have profound impacts to 2612 the security of outbound connections from the device. Since 2613 knowledge of authorization rules and certificate usage mechanisms 2614 may be considered sensitive, protection from disclosure of the 2615 SNMP traffic via encryption is also highly recommended. 2617 o The snmpTlstmAddrTable can be used to change the expectations of 2618 the certificates presented by a remote (D)TLS server. 2619 Modification to objects in this table need to be adequately 2620 authenticated since modification to values in this table will have 2621 profound impacts to the security of outbound connections from the 2622 device. Since knowledge of authorization rules and certificate 2623 usage mechanisms may be considered sensitive, protection from 2624 disclosure of the SNMP traffic via encryption is also highly 2625 recommended. 2627 o The snmpTlstmCertToTSNTable is used to specify the mapping of 2628 incoming X.509 certificates to tmSecurityNames which eventually 2629 get mapped to a SNMPv3 securityName. Modification to objects in 2630 this table need to be adequately authenticated since modification 2631 to values in this table will have profound impacts to the security 2632 of incoming connections to the device. Since knowledge of 2633 authorization rules and certificate usage mechanisms may be 2634 considered sensitive, protection from disclosure of the SNMP 2635 traffic via encryption is also highly recommended. When this 2636 table contains a significant number of rows it may affect the 2637 system performance when accepting new (D)TLS connections. 2639 Some of the readable objects in this MIB module (i.e., objects with a 2640 MAX-ACCESS other than not-accessible) may be considered sensitive or 2641 vulnerable in some network environments. It is thus important to 2642 control even GET and/or NOTIFY access to these objects and possibly 2643 to even encrypt the values of these objects when sending them over 2644 the network via SNMP. These are the tables and objects and their 2645 sensitivity/vulnerability: 2647 o This MIB contains a collection of counters that monitor the (D)TLS 2648 connections being established with a device. Since knowledge of 2649 connection and certificate usage mechanisms may be considered 2650 sensitive, protection from disclosure of the SNMP traffic via 2651 encryption is also highly recommended. 2653 SNMP versions prior to SNMPv3 did not include adequate security. 2654 Even if the network itself is secure (for example by using IPsec), 2655 even then, there is no control as to who on the secure network is 2656 allowed to access and GET/SET (read/change/create/delete) the objects 2657 in this MIB module. 2659 It is RECOMMENDED that implementers consider the security features as 2660 provided by the SNMPv3 framework (see [RFC3410], section 8), 2661 including full support for the SNMPv3 cryptographic mechanisms (for 2662 authentication and privacy). 2664 Further, deployment of SNMP versions prior to SNMPv3 is NOT 2665 RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to 2666 enable cryptographic security. It is then a customer/operator 2667 responsibility to ensure that the SNMP entity giving access to an 2668 instance of this MIB module is properly configured to give access to 2669 the objects only to those principals (users) that have legitimate 2670 rights to indeed GET or SET (change/create/delete) them. 2672 10. IANA Considerations 2674 IANA is requested to assign: 2676 1. Two TCP/UDP port numbers from the "Registered Ports" range of the 2677 Port Numbers registry, with the following keywords (where TBD1 2678 and TBD2 correspond to the assigned port numbers): 2680 Keyword Decimal Description References 2681 ------- ------- ----------- ---------- 2682 snmptls TBD1/tcp SNMP-TLS [RFC-isms-dtls-tm] 2683 snmpdtls TBD1/udp SNMP-DTLS [RFC-isms-dtls-tm] 2684 snmptls-trap TBD2/tcp SNMP-Trap-TLS [RFC-isms-dtls-tm] 2685 snmpdtls-trap TBD2/udp SNMP-Trap-DTLS [RFC-isms-dtls-tm] 2687 These are the default ports for receipt of SNMP command messages 2688 (snmptls and snmpdtls) and SNMP notification messages (snmptls- 2689 trap and snmpdtls-trap) over a TLS Transport Model as defined in 2690 this document. 2692 2. An SMI number under snmpDomains for the snmpTLSTCPDomain object 2693 identifier, 2695 3. An SMI number under snmpDomains for the snmpDTLSUDPDomain object 2696 identifier, 2698 4. A SMI number under mib-2, for the MIB module in this document, 2700 5. "tls" as the corresponding prefix for the snmpTLSTCPDomain in the 2701 SNMP Transport Model registry, 2703 6. "dtls" as the corresponding prefix for the snmpDTLSUDPDomain in 2704 the SNMP Transport Model registry, 2706 RFC Editor's note: this section should be replaced with appropriate 2707 descriptive assignment text after IANA assignments are made and prior 2708 to publication. 2710 11. Acknowledgements 2712 This document closely follows and copies the Secure Shell Transport 2713 Model for SNMP documented by David Harrington and Joseph Salowey in 2714 [RFC5592]. 2716 This document was reviewed by the following people who helped provide 2717 useful comments (in alphabetical order): Andy Donati, Pasi Eronen, 2718 David Harrington, Jeffrey Hutzelman, Alan Luchuk, Michael Peck, Tom 2719 Petch, Randy Presuhn, Ray Purvis, Peter Saint-Andre, Joseph Salowey, 2720 Jurgen Schonwalder, Dave Shield, Robert Story. 2722 This work was supported in part by the United States Department of 2723 Defense. Large portions of this document are based on work by 2724 General Dynamics C4 Systems and the following individuals: Brian 2725 Baril, Kim Bryant, Dana Deluca, Dan Hanson, Tim Huemiller, John 2726 Holzhauer, Colin Hoogeboom, Dave Kornbau, Chris Knaian, Dan Knaul, 2727 Charles Limoges, Steve Moccaldi, Gerardo Orlando, and Brandon Yip. 2729 12. References 2731 12.1. Normative References 2733 [RFC1033] Lottor, M., "Domain administrators operations guide", 2734 RFC 1033, November 1987. 2736 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2737 Requirement Levels", BCP 14, RFC 2119, March 1997. 2739 [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. 2740 Schoenwaelder, Ed., "Structure of Management Information 2741 Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. 2743 [RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J. 2744 Schoenwaelder, Ed., "Textual Conventions for SMIv2", 2745 STD 58, RFC 2579, April 1999. 2747 [RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder, 2748 "Conformance Statements for SMIv2", STD 58, RFC 2580, 2749 April 1999. 2751 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 2752 Architecture for Describing Simple Network Management 2753 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 2754 December 2002. 2756 [RFC3413] Levi, D., Meyer, P., and B. Stewart, "Simple Network 2757 Management Protocol (SNMP) Applications", STD 62, 2758 RFC 3413, December 2002. 2760 [RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model 2761 (USM) for version 3 of the Simple Network Management 2762 Protocol (SNMPv3)", STD 62, RFC 3414, December 2002. 2764 [RFC3415] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based 2765 Access Control Model (VACM) for the Simple Network 2766 Management Protocol (SNMP)", STD 62, RFC 3415, 2767 December 2002. 2769 [RFC3418] Presuhn, R., "Management Information Base (MIB) for the 2770 Simple Network Management Protocol (SNMP)", STD 62, 2771 RFC 3418, December 2002. 2773 [RFC3490] Faltstrom, P., Hoffman, P., and A. Costello, 2774 "Internationalizing Domain Names in Applications (IDNA)", 2775 RFC 3490, March 2003. 2777 [RFC3584] Frye, R., Levi, D., Routhier, S., and B. Wijnen, 2778 "Coexistence between Version 1, Version 2, and Version 3 2779 of the Internet-standard Network Management Framework", 2780 BCP 74, RFC 3584, August 2003. 2782 [RFC4347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer 2783 Security", RFC 4347, April 2006. 2785 [RFC4366] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., 2786 and T. Wright, "Transport Layer Security (TLS) 2787 Extensions", RFC 4366, April 2006. 2789 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 2790 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 2792 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 2793 Housley, R., and W. Polk, "Internet X.509 Public Key 2794 Infrastructure Certificate and Certificate Revocation List 2795 (CRL) Profile", RFC 5280, May 2008. 2797 [RFC5590] Harrington, D. and J. Schoenwaelder, "Transport Subsystem 2798 for the Simple Network Management Protocol (SNMP)", 2799 RFC 5590, June 2009. 2801 [RFC5591] Harrington, D. and W. Hardaker, "Transport Security Model 2802 for the Simple Network Management Protocol (SNMP)", 2803 RFC 5591, June 2009. 2805 [I-D.draft-ietf-6man-text-addr-representation] 2806 Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 2807 Address Text Representation". 2809 12.2. Informative References 2811 [RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, 2812 "Introduction and Applicability Statements for Internet- 2813 Standard Management Framework", RFC 3410, December 2002. 2815 [RFC5343] Schoenwaelder, J., "Simple Network Management Protocol 2816 (SNMP) Context EngineID Discovery", RFC 5343, 2817 September 2008. 2819 [RFC5592] Harrington, D., Salowey, J., and W. Hardaker, "Secure 2820 Shell Transport Model for the Simple Network Management 2821 Protocol (SNMP)", RFC 5592, June 2009. 2823 [I-D.seggelmann-tls-dtls-heartbeat] 2824 Seggelmann, R., Tuexen, M., and M. Williams, "Transport 2825 Layer Security and Datagram Transport Layer Security 2826 Heartbeat Extension". 2828 Appendix A. Target and Notification Configuration Example 2830 The following sections describe example configuration for the SNMP- 2831 TLS-TM-MIB, the SNMP-TARGET-MIB, the NOTIFICATION-MIB and the SNMP- 2832 VIEW-BASED-ACM-MIB. 2834 A.1. Configuring a Notification Originator 2836 The following row adds the "Joe Cool" user to the "administrators" 2837 group: 2839 vacmSecurityModel = 4 (TSM) 2840 vacmSecurityName = "Joe Cool" 2841 vacmGroupName = "administrators" 2842 vacmSecurityToGroupStorageType = 3 (nonVolatile) 2843 vacmSecurityToGroupStatus = 4 (createAndGo) 2845 The following row configures the snmpTlstmAddrTable to use 2846 certificate path validation and to require the remote notification 2847 receiver to present a certificate for the "server.example.org" 2848 identity. 2850 snmpTargetAddrName = "toNRAddr" 2851 snmpTlstmAddrServerFingerprint = "" 2852 snmpTlstmAddrServerIdentity = "server.example.org" 2853 snmpTlstmAddrStorageType = 3 (nonVolatile) 2854 snmpTlstmAddrRowStatus = 4 (createAndGo) 2856 The following row configures the snmpTargetAddrTable to send 2857 notifications using TLS/TCP to the snmptls-trap port at 192.0.2.1: 2859 snmpTargetAddrName = "toNRAddr" 2860 snmpTargetAddrTDomain = snmpTLSTCPDomain 2861 snmpTargetAddrTAddress = "192.0.2.1:XXXsnmptls-trap" 2862 snmpTargetAddrTimeout = 1500 2863 snmpTargetAddrRetryCount = 3 2864 snmpTargetAddrTagList = "toNRTag" 2865 snmpTargetAddrParams = "toNR" (MUST match above) 2866 snmpTargetAddrStorageType = 3 (nonVolatile) 2867 snmpTargetAddrColumnStatus = 4 (createAndGo) 2869 RFC Editor's note: replace the string "XXXsnmptls-trap" above with 2870 the appropriately assigned "snmptls-trap" port. 2872 The following row configures the snmpTargetParamsTable to send the 2873 notifications to "Joe Cool", using authPriv SNMPv3 notifications 2874 through the TransportSecurityModel [RFC5591]: 2876 snmpTargetParamsName = toNR 2877 snmpTargetParamsMPModel = SNMPv3 2878 snmpTargetParamsSecurityModel = 4 (TransportSecurityModel) 2879 snmpTargetParamsSecurityName = "Joe Cool" 2880 snmpTargetParamsSecurityLevel = 3 (authPriv) 2881 snmpTargetParamsStorageType = 3 (nonVolatile) 2882 snmpTargetParamsRowStatus = 4 (createAndGo0 2884 A.2. Configuring TLSTM to Utilize a Simple Derivation of tmSecurityName 2886 The following row configures the snmpTlstmCertToTSNTable to map a 2887 validated client certificate, referenced by the client's public X.509 2888 hash fingerprint, to a tmSecurityName using the subjectAltName 2889 component of the certificate. 2891 snmpTlstmCertToTSNID = 1 2892 (chosen by ordering preference) 2893 snmpTlstmCertToTSNFingerprint = HASH (appropriate fingerprint) 2894 snmpTlstmCertToTSNMapType = snmpTlstmCertSANAny 2895 snmpTlstmCertToTSNData = "" (not used) 2896 snmpTlstmCertToTSNStorageType = 3 (nonVolatile) 2897 snmpTlstmCertToTSNRowStatus = 4 (createAndGo) 2899 This type of configuration should only be used when the naming 2900 conventions of the (possibly multiple) certificate authorities are 2901 well understood, so two different principals cannot inadvertently be 2902 identified by the same derived tmSecurityName. 2904 A.3. Configuring TLSTM to Utilize Table-Driven Certificate Mapping 2906 The following row configures the snmpTlstmCertToTSNTable to map a 2907 validated client certificate, referenced by the client's public X.509 2908 hash fingerprint, to the directly specified tmSecurityName of "Joe 2909 Cool". 2911 snmpTlstmCertToTSNID = 1 2912 (chosen by ordering preference) 2913 snmpTlstmCertToTSNFingerprint = HASH (appropriate fingerprint) 2914 snmpTlstmCertToTSNMapType = snmpTlstmCertSpecified 2915 snmpTlstmCertToTSNSecurityName = "Joe Cool" 2916 snmpTlstmCertToTSNStorageType = 3 (nonVolatile) 2917 snmpTlstmCertToTSNRowStatus = 4 (createAndGo) 2919 Author's Address 2921 Wes Hardaker 2922 Sparta, Inc. 2923 P.O. Box 382 2924 Davis, CA 95617 2925 USA 2927 Phone: +1 530 792 1913 2928 Email: ietf@hardakers.net