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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 6, 2010 5 Expires: November 7, 2010 7 Transport Layer Security (TLS) Transport Model for the Simple Network 8 Management Protocol (SNMP) 9 draft-ietf-isms-dtls-tm-12.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 7, 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 . . . . . . . . . . . . . . . . . . 20 107 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 . . . . 21 110 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 . . . . . . . . . . . . . . . . . . 53 126 8.1. Sessions . . . . . . . . . . . . . . . . . . . . . . . . . 53 127 8.2. Notification Receiver Credential Selection . . . . . . . . 54 128 8.3. contextEngineID Discovery . . . . . . . . . . . . . . . . 54 129 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 . . . . . . . . . . . . . . . 56 135 9.3. Use with SNMPv1/SNMPv2c Messages . . . . . . . . . . . . . 56 136 9.4. MIB Module Security . . . . . . . . . . . . . . . . . . . 57 137 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58 138 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 59 139 12. References . . . . . . . . . . . . . . . . . . . . . . . . . . 60 140 12.1. Normative References . . . . . . . . . . . . . . . . . . . 60 141 12.2. Informative References . . . . . . . . . . . . . . . . . . 61 142 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 . . . . . . . . . . . . . . . . . . . . . . . . . 63 148 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). 843 Transport-model-aware security models derive tmSecurityName from a 844 securityName, possibly configured in MIB modules for notifications 845 and access controls. Transport Models SHOULD use predictable 846 tmSecurityNames so operators will know what to use when configuring 847 MIB modules that use securityNames derived from tmSecurityNames. The 848 TLSTM generates predictable tmSecurityNames based on the 849 configuration found in the SNMP-TLS-TM-MIB's snmpTlstmCertToTSNTable 850 and relies on the network operators to have configured this table 851 appropriately. 853 4.4.1.2. tmSessionID 855 The tmSessionID MUST be recorded per message at the time of receipt. 856 When tmSameSecurity is set, the recorded tmSessionID can be used to 857 determine whether the (D)TLS connection available for sending a 858 corresponding outgoing message is the same (D)TLS connection as was 859 used when receiving the incoming message (e.g., a response to a 860 request). 862 4.4.1.3. Session State 864 The per-session state that is referenced by tmStateReference may be 865 saved across multiple messages in a Local Configuration Datastore. 866 Additional session/connection state information might also be stored 867 in a Local Configuration Datastore. 869 5. Elements of Procedure 871 Abstract service interfaces have been defined by [RFC3411] and 872 further augmented by [RFC5590] to describe the conceptual data flows 873 between the various subsystems within an SNMP entity. The TLSTM uses 874 some of these conceptual data flows when communicating between 875 subsystems. 877 To simplify the elements of procedure, the release of state 878 information is not always explicitly specified. As a general rule, 879 if state information is available when a message gets discarded, the 880 message-state information should also be released. If state 881 information is available when a session is closed, the session state 882 information should also be released. Sensitive information, like 883 cryptographic keys, should be overwritten appropriately prior to 884 being released. 886 An error indication in statusInformation will typically include the 887 Object Identifier (OID) and value for an incremented error counter. 888 This may be accompanied by the requested securityLevel and the 889 tmStateReference. Per-message context information is not accessible 890 to Transport Models, so for the returned counter OID and value, 891 contextEngine would be set to the local value of snmpEngineID and 892 contextName to the default context for error counters. 894 5.1. Procedures for an Incoming Message 896 This section describes the procedures followed by the (D)TLS 897 Transport Model when it receives a (D)TLS protected packet. The 898 required functionality is broken into two different sections. 900 Section 5.1.1 describes the processing required for de-multiplexing 901 multiple DTLS connections, which is specifically needed for DTLS over 902 UDP sessions. It is assumed that TLS protocol implementations 903 already provide appropriate message demultiplexing. 905 Section 5.1.2 describes the transport processing required once the 906 (D)TLS processing has been completed. This will be needed for all 907 (D)TLS-based connections. 909 5.1.1. DTLS over UDP Processing for Incoming Messages 911 For connection-oriented transport protocols, such as TCP, the 912 transport protocol takes care of demultiplexing incoming packets to 913 the right connection. Depending on the DTLS implementation, for DTLS 914 over UDP, this demultiplexing may need to be done by the TLSTM 915 implementation. 917 Like TCP, DTLS over UDP uses the four-tuple for identifying the connection 919 (and relevant DTLS connection state). This means that when 920 establishing a new session, implementations MUST use a different UDP 921 source port number for each active connection to a remote destination 922 IP-address/port-number combination to ensure the remote entity can 923 disambiguate between multiple connections. 925 If demultiplexing received UDP datagrams to DTLS connection state is 926 done by the TLSTM implementation (instead of the DTLS 927 implementation), the steps below describe one possible method to 928 accomplish this. 930 The important output results from the steps in this process are the 931 remote transport address, incomingMessage, incomingMessageLength, and 932 the tlstmSessionID. 934 1) The TLS Transport Model examines the raw UDP message, in an 935 implementation-dependent manner. 937 2) The TLS Transport Model queries the Local Configuration Datastore 938 (LCD) (see [RFC3411] Section 3.4.2) using the transport 939 parameters (source and destination IP addresses and ports) to 940 determine if a session already exists. 942 2a) If a matching entry in the LCD does not exist, then the UDP 943 packet is passed to the DTLS implementation for processing. 944 If the DTLS implementation decides to continue with the 945 connection and allocate state for it, it returns a new DTLS 946 connection handle (an implementation dependent detail). In 947 this case, TLSTM selects a new tlstmSessionId, and caches 948 this and the DTLS connection handle as a new entry in the 949 LCD (indexed by the transport parameters). If the DTLS 950 implementation returns an error or does not allocate 951 connection state (which can happen with the stateless cookie 952 exchange), processing stops. 954 2b) If a session does exist in the LCD then its DTLS connection 955 handle (an implementation dependent detail) and its 956 tlstmSessionId is extracted from the LCD. The UDP packet 957 and the connection handle is passed to the DTLS 958 implementation. If the DTLS implementation returns success 959 but does not return an incomingMessage and an 960 incomingMessageLength then processing stops (this is the 961 case when the UDP datagram contained DTLS handshake 962 messages, for example). If the DTLS implementation returns 963 an error then processing stops. 965 3) Retrieve the incomingMessage and an incomingMessageLength from 966 DTLS. These results and the tlstmSessionID are used below in 967 Section 5.1.2 to complete the processing of the incoming message. 969 5.1.2. Transport Processing for Incoming SNMP Messages 971 The procedures in this section describe how the TLS Transport Model 972 should process messages that have already been properly extracted 973 from the (D)TLS stream. Note that care must be taken when processing 974 messages originating from either TLS or DTLS to ensure they're 975 complete and single. For example, multiple SNMP messages can be 976 passed through a single DTLS message and partial SNMP messages may be 977 received from a TLS stream. These steps describe the processing of a 978 singular SNMP message after it has been delivered from the (D)TLS 979 stream. 981 1) Determine the tlstmSessionID for the incoming message. The 982 tlstmSessionID MUST be a unique session identifier for this 983 (D)TLS connection. The contents and format of this identifier 984 are implementation-dependent as long as it is unique to the 985 session. A session identifier MUST NOT be reused until all 986 references to it are no longer in use. The tmSessionID is equal 987 to the tlstmSessionID discussed in Section 5.1.1. tmSessionID 988 refers to the session identifier when stored in the 989 tmStateReference and tlstmSessionID refers to the session 990 identifier when stored in the LCD. They MUST always be equal 991 when processing a given session's traffic. 993 If this is the first message received through this session and 994 the session does not have an assigned tlstmSessionID yet then the 995 snmpTlstmSessionAccepts counter is incremented and a 996 tlstmSessionID for the session is created. This will only happen 997 on the server side of a connection because a client would have 998 already assigned a tlstmSessionID during the openSession() 999 invocation. Implementations may have performed the procedures 1000 described in Section 5.3.2 prior to this point or they may 1001 perform them now, but the procedures described in Section 5.3.2 1002 MUST be performed before continuing beyond this point. 1004 2) Create a tmStateReference cache for the subsequent reference and 1005 assign the following values within it: 1007 tmTransportDomain = snmpTLSTCPDomain or snmpDTLSUDPDomain as 1008 appropriate. 1010 tmTransportAddress = The address the message originated from. 1012 tmSecurityLevel = The derived tmSecurityLevel for the session, 1013 as discussed in Section 3.1.2 and Section 5.3. 1015 tmSecurityName = The derived tmSecurityName for the session as 1016 discussed in Section 5.3. This value MUST be constant during 1017 the lifetime of the session. 1019 tmSessionID = The tlstmSessionID described in step 1 above. 1021 3) The incomingMessage and incomingMessageLength are assigned values 1022 from the (D)TLS processing. 1024 4) The TLS Transport Model passes the transportDomain, 1025 transportAddress, incomingMessage, and incomingMessageLength to 1026 the Dispatcher using the receiveMessage ASI: 1028 statusInformation = 1029 receiveMessage( 1030 IN transportDomain -- snmpTLSTCPDomain or snmpDTLSUDPDomain, 1031 IN transportAddress -- address for the received message 1032 IN incomingMessage -- the whole SNMP message from (D)TLS 1033 IN incomingMessageLength -- the length of the SNMP message 1034 IN tmStateReference -- transport info 1035 ) 1037 5.2. Procedures for an Outgoing SNMP Message 1039 The Dispatcher sends a message to the TLS Transport Model using the 1040 following ASI: 1042 statusInformation = 1043 sendMessage( 1044 IN destTransportDomain -- transport domain to be used 1045 IN destTransportAddress -- transport address to be used 1046 IN outgoingMessage -- the message to send 1047 IN outgoingMessageLength -- its length 1048 IN tmStateReference -- transport info 1049 ) 1051 This section describes the procedure followed by the TLS Transport 1052 Model whenever it is requested through this ASI to send a message. 1054 1) If tmStateReference does not refer to a cache containing values 1055 for tmTransportDomain, tmTransportAddress, tmSecurityName, 1056 tmRequestedSecurityLevel, and tmSameSecurity, then increment the 1057 snmpTlstmSessionInvalidCaches counter, discard the message, and 1058 return the error indication in the statusInformation. Processing 1059 of this message stops. 1061 2) Extract the tmSessionID, tmTransportDomain, tmTransportAddress, 1062 tmSecurityName, tmRequestedSecurityLevel, and tmSameSecurity 1063 values from the tmStateReference. Note: The tmSessionID value 1064 may be undefined if no session exists yet over which the message 1065 can be sent. 1067 3) If tmSameSecurity is true and either tmSessionID is undefined or 1068 refers to a session that is no longer open then increment the 1069 snmpTlstmSessionNoSessions counter, discard the message and 1070 return the error indication in the statusInformation. Processing 1071 of this message stops. 1073 4) If tmSameSecurity is false and tmSessionID refers to a session 1074 that is no longer available then an implementation SHOULD open a 1075 new session using the openSession() ASI (described in greater 1076 detail in step 5b). Instead of opening a new session an 1077 implementation MAY return a snmpTlstmSessionNoSessions error to 1078 the calling module and stop processing of the message. 1080 5) If tmSessionID is undefined, then use tmTransportDomain, 1081 tmTransportAddress, tmSecurityName and tmRequestedSecurityLevel 1082 to see if there is a corresponding entry in the LCD suitable to 1083 send the message over. 1085 5a) If there is a corresponding LCD entry, then this session 1086 will be used to send the message. 1088 5b) If there is no corresponding LCD entry, then open a session 1089 using the openSession() ASI (discussed further in 1090 Section 5.3.1). Implementations MAY wish to offer message 1091 buffering to prevent redundant openSession() calls for the 1092 same cache entry. If an error is returned from 1093 openSession(), then discard the message, discard the 1094 tmStateReference, increment the snmpTlstmSessionOpenErrors, 1095 return an error indication to the calling module and stop 1096 processing of the message. 1098 6) Using either the session indicated by the tmSessionID if there 1099 was one or the session resulting from a previous step (4 or 5), 1100 pass the outgoingMessage to (D)TLS for encapsulation and 1101 transmission. 1103 5.3. Establishing or Accepting a Session 1105 Establishing a (D)TLS connection as either a client or a server 1106 requires slightly different processing. The following two sections 1107 describe the necessary processing steps. 1109 5.3.1. Establishing a Session as a Client 1111 The TLS Transport Model provides the following primitive for use by a 1112 client to establish a new (D)TLS connection: 1114 statusInformation = -- errorIndication or success 1115 openSession( 1116 IN tmStateReference -- transport information to be used 1117 OUT tmStateReference -- transport information to be used 1118 IN maxMessageSize -- of the sending SNMP entity 1119 ) 1121 The following describes the procedure to follow when establishing a 1122 SNMP over (D)TLS connection between SNMP engines for exchanging SNMP 1123 messages. This process is followed by any SNMP client's engine when 1124 establishing a session for subsequent use. 1126 This procedure MAY be done automatically for an SNMP application that 1127 initiates a transaction, such as a command generator, a notification 1128 originator, or a proxy forwarder. 1130 1) The snmpTlstmSessionOpens counter is incremented. 1132 2) The client selects the appropriate certificate and cipher_suites 1133 for the key agreement based on the tmSecurityName and the 1134 tmRequestedSecurityLevel for the session. For sessions being 1135 established as a result of a SNMP-TARGET-MIB based operation, the 1136 certificate will potentially have been identified via the 1137 snmpTlstmParamsTable mapping and the cipher_suites will have to 1138 be taken from system-wide or implementation-specific 1139 configuration. If no row in the snmpTlstmParamsTable exists then 1140 implementations MAY choose to establish the connection using a 1141 default client certificate available to the application. 1142 Otherwise, the certificate and appropriate cipher_suites will 1143 need to be passed to the openSession() ASI as supplemental 1144 information or configured through an implementation-dependent 1145 mechanism. It is also implementation-dependent and possibly 1146 policy-dependent how tmRequestedSecurityLevel will be used to 1147 influence the security capabilities provided by the (D)TLS 1148 connection. However this is done, the security capabilities 1149 provided by (D)TLS MUST be at least as high as the level of 1150 security indicated by the tmRequestedSecurityLevel parameter. 1151 The actual security level of the session is reported in the 1152 tmStateReference cache as tmSecurityLevel. For (D)TLS to provide 1153 strong authentication, each principal acting as a command 1154 generator SHOULD have its own certificate. 1156 3) Using the destTransportDomain and destTransportAddress values, 1157 the client will initiate the (D)TLS handshake protocol to 1158 establish session keys for message integrity and encryption. 1160 If the attempt to establish a session is unsuccessful, then 1161 snmpTlstmSessionOpenErrors is incremented, an error indication is 1162 returned, and processing stops. If the session failed to open 1163 because the presented server certificate was unknown or invalid 1164 then the snmpTlstmSessionUnknownServerCertificate or 1165 snmpTlstmSessionInvalidServerCertificates MUST be incremented and 1166 a snmpTlstmServerCertificateUnknown or 1167 snmpTlstmServerInvalidCertificate notification SHOULD be sent as 1168 appropriate. Reasons for server certificate invalidation 1169 includes, but is not limited to, cryptographic validation 1170 failures and an unexpected presented certificate identity. 1172 4) The (D)TLS client MUST then verify that the (D)TLS server's 1173 presented certificate is the expected certificate. The (D)TLS 1174 client MUST NOT transmit SNMP messages until the server 1175 certificate has been authenticated, the client certificate has 1176 been transmitted and the TLS connection has been fully 1177 established. 1179 If the connection is being established from configuration based 1180 on SNMP-TARGET-MIB configuration, then the snmpTlstmAddrTable 1181 DESCRIPTION clause describes how the verification is done (using 1182 either a certificate fingerprint, or an identity authenticated 1183 via certification path validation). 1185 If the connection is being established for reasons other than 1186 configuration found in the SNMP-TARGET-MIB then configuration and 1187 procedures outside the scope of this document should be followed. 1188 Configuration mechanisms SHOULD be similar in nature to those 1189 defined in the snmpTlstmAddrTable to ensure consistency across 1190 management configuration systems. For example, a command-line 1191 tool for generating SNMP GETs might support specifying either the 1192 server's certificate fingerprint or the expected host name as a 1193 command line argument. 1195 5) (D)TLS provides assurance that the authenticated identity has 1196 been signed by a trusted configured certification authority. If 1197 verification of the server's certificate fails in any way (for 1198 example because of failures in cryptographic verification or the 1199 presented identity did not match the expected named entity) then 1200 the session establishment MUST fail, the 1201 snmpTlstmSessionInvalidServerCertificates object is incremented. 1202 If the session can not be opened for any reason at all, including 1203 cryptographic verification failures and snmpTlstmCertToTSNTable 1204 lookup failures, then the snmpTlstmSessionOpenErrors counter is 1205 incremented and processing stops. 1207 6) The TLSTM-specific session identifier (tlstmSessionID) is set in 1208 the tmSessionID of the tmStateReference passed to the TLS 1209 Transport Model to indicate that the session has been established 1210 successfully and to point to a specific (D)TLS connection for 1211 future use. The tlstmSessionID is also stored in the LCD for 1212 later lookup during processing of incoming messages 1213 (Section 5.1.2). 1215 5.3.2. Accepting a Session as a Server 1217 A (D)TLS server should accept new session connections from any client 1218 that it is able to verify the client's credentials for. This is done 1219 by authenticating the client's presented certificate through a 1220 certificate path validation process (e.g. [RFC5280]) or through 1221 certificate fingerprint verification using fingerprints configured in 1222 the snmpTlstmCertToTSNTable. Afterward the server will determine the 1223 identity of the remote entity using the following procedures. 1225 The (D)TLS server identifies the authenticated identity from the 1226 (D)TLS client's principal certificate using configuration information 1227 from the snmpTlstmCertToTSNTable mapping table. The (D)TLS server 1228 MUST request and expect a certificate from the client and MUST NOT 1229 accept SNMP messages over the (D)TLS connection until the client has 1230 sent a certificate and it has been authenticated. The resulting 1231 derived tmSecurityName is recorded in the tmStateReference cache as 1232 tmSecurityName. The details of the lookup process are fully 1233 described in the DESCRIPTION clause of the snmpTlstmCertToTSNTable 1234 MIB object. If any verification fails in any way (for example 1235 because of failures in cryptographic verification or because of the 1236 lack of an appropriate row in the snmpTlstmCertToTSNTable) then the 1237 session establishment MUST fail, and the 1238 snmpTlstmSessionInvalidClientCertificates object is incremented. If 1239 the session can not be opened for any reason at all, including 1240 cryptographic verification failures, then the 1241 snmpTlstmSessionOpenErrors counter is incremented and processing 1242 stops. 1244 Servers that wish to support multiple principals at a particular port 1245 SHOULD make use of a (D)TLS extension that allows server-side 1246 principal selection like the Server Name Indication extension defined 1247 in Section 3.1 of [RFC4366]. Supporting this will allow, for 1248 example, sending notifications to a specific principal at a given TCP 1249 or UDP port. 1251 5.4. Closing a Session 1253 The TLS Transport Model provides the following primitive to close a 1254 session: 1256 statusInformation = 1257 closeSession( 1258 IN tmSessionID -- session ID of the session to be closed 1259 ) 1261 The following describes the procedure to follow to close a session 1262 between a client and server. This process is followed by any SNMP 1263 engine closing the corresponding SNMP session. 1265 1) Increment either the snmpTlstmSessionClientCloses or the 1266 snmpTlstmSessionServerCloses counter as appropriate. 1268 2) Look up the session using the tmSessionID. 1270 3) If there is no open session associated with the tmSessionID, then 1271 closeSession processing is completed. 1273 4) Have (D)TLS close the specified connection. This MUST include 1274 sending a close_notify TLS Alert to inform the other side that 1275 session cleanup may be performed. 1277 6. MIB Module Overview 1279 This MIB module provides management of the TLS Transport Model. It 1280 defines needed textual conventions, statistical counters, 1281 notifications and configuration infrastructure necessary for session 1282 establishment. Example usage of the configuration tables can be 1283 found in Appendix A. 1285 6.1. Structure of the MIB Module 1287 Objects in this MIB module are arranged into subtrees. Each subtree 1288 is organized as a set of related objects. The overall structure and 1289 assignment of objects to their subtrees, and the intended purpose of 1290 each subtree, is shown below. 1292 6.2. Textual Conventions 1294 Generic and Common Textual Conventions used in this module can be 1295 found summarized at http://www.ops.ietf.org/mib-common-tcs.html 1297 This module defines the following new Textual Conventions: 1299 o A new TransportAddress format for describing (D)TLS connection 1300 addressing requirements. 1302 o A certificate fingerprint allowing MIB module objects to 1303 generically refer to a stored X.509 certificate using a 1304 cryptographic hash as a reference pointer. 1306 6.3. Statistical Counters 1308 The SNMP-TLS-TM-MIB defines counters that provide network management 1309 stations with information about session usage and potential errors 1310 that a device may be experiencing. 1312 6.4. Configuration Tables 1314 The SNMP-TLS-TM-MIB defines configuration tables that an 1315 administrator can use for configuring a device for sending and 1316 receiving SNMP messages over (D)TLS. In particular, there are MIB 1317 tables that extend the SNMP-TARGET-MIB for configuring (D)TLS 1318 certificate usage and a MIB table for mapping incoming (D)TLS client 1319 certificates to SNMPv3 securityNames. 1321 6.4.1. Notifications 1323 The SNMP-TLS-TM-MIB defines notifications to alert management 1324 stations when a (D)TLS connection fails because a server's presented 1325 certificate did not meet an expected value 1326 (snmpTlstmServerCertificateUnknown) or because cryptographic 1327 validation failed (snmpTlstmServerInvalidCertificate). 1329 6.5. Relationship to Other MIB Modules 1331 Some management objects defined in other MIB modules are applicable 1332 to an entity implementing the TLS Transport Model. In particular, it 1333 is assumed that an entity implementing the SNMP-TLS-TM-MIB will 1334 implement the SNMPv2-MIB [RFC3418], the SNMP-FRAMEWORK-MIB [RFC3411], 1335 the SNMP-TARGET-MIB [RFC3413], the SNMP-NOTIFICATION-MIB [RFC3413] 1336 and the SNMP-VIEW-BASED-ACM-MIB [RFC3415]. 1338 The SNMP-TLS-TM-MIB module contained in this document is for managing 1339 TLS Transport Model information. 1341 6.5.1. MIB Modules Required for IMPORTS 1343 The SNMP-TLS-TM-MIB module imports items from SNMPv2-SMI [RFC2578], 1344 SNMPv2-TC [RFC2579], SNMP-FRAMEWORK-MIB [RFC3411], SNMP-TARGET-MIB 1345 [RFC3413] and SNMPv2-CONF [RFC2580]. 1347 7. MIB Module Definition 1349 SNMP-TLS-TM-MIB DEFINITIONS ::= BEGIN 1351 IMPORTS 1352 MODULE-IDENTITY, OBJECT-TYPE, 1353 OBJECT-IDENTITY, mib-2, snmpDomains, 1354 Counter32, Unsigned32, Gauge32, NOTIFICATION-TYPE 1355 FROM SNMPv2-SMI -- RFC2578 or any update thereof 1356 TEXTUAL-CONVENTION, TimeStamp, RowStatus, StorageType, 1357 AutonomousType 1358 FROM SNMPv2-TC -- RFC2579 or any update thereof 1359 MODULE-COMPLIANCE, OBJECT-GROUP, NOTIFICATION-GROUP 1360 FROM SNMPv2-CONF -- RFC2580 or any update thereof 1361 SnmpAdminString 1362 FROM SNMP-FRAMEWORK-MIB -- RFC3411 or any update thereof 1363 snmpTargetParamsName, snmpTargetAddrName 1364 FROM SNMP-TARGET-MIB -- RFC3413 or any update thereof 1365 ; 1367 snmpTlstmMIB MODULE-IDENTITY 1368 LAST-UPDATED "201005060000Z" 1369 ORGANIZATION "ISMS Working Group" 1370 CONTACT-INFO "WG-EMail: isms@lists.ietf.org 1371 Subscribe: isms-request@lists.ietf.org 1373 Chairs: 1374 Juergen Schoenwaelder 1375 Jacobs University Bremen 1376 Campus Ring 1 1377 28725 Bremen 1378 Germany 1379 +49 421 200-3587 1380 j.schoenwaelder@jacobs-university.de 1382 Russ Mundy 1383 SPARTA, Inc. 1384 7110 Samuel Morse Drive 1385 Columbia, MD 21046 1386 USA 1388 Editor: 1389 Wes Hardaker 1390 Sparta, Inc. 1391 P.O. Box 382 1392 Davis, CA 95617 1393 USA 1394 ietf@hardakers.net 1395 " 1397 DESCRIPTION " 1398 The TLS Transport Model MIB 1400 Copyright (c) 2010 IETF Trust and the persons identified as 1401 the document authors. All rights reserved. 1403 Redistribution and use in source and binary forms, with or 1404 without modification, is permitted pursuant to, and subject 1405 to the license terms contained in, the Simplified BSD License 1406 set forth in Section 4.c of the IETF Trust's Legal Provisions 1407 Relating to IETF Documents 1408 (http://trustee.ietf.org/license-info)." 1410 REVISION "201005060000Z" 1411 DESCRIPTION "This version of this MIB module is part of 1412 RFC XXXX; see the RFC itself for full legal 1413 notices." 1415 -- NOTE to RFC editor: replace XXXX with actual RFC number 1416 -- for this document and change the date to the 1417 -- current date and remove this note 1419 ::= { mib-2 www } 1420 -- RFC Ed.: replace www with IANA-assigned number under the mib-2 1421 -- SNMP OID tree and remove this note 1423 -- ************************************************ 1424 -- subtrees of the SNMP-TLS-TM-MIB 1425 -- ************************************************ 1426 snmpTlstmNotifications OBJECT IDENTIFIER ::= { snmpTlstmMIB 0 } 1427 snmpTlstmIdentities OBJECT IDENTIFIER ::= { snmpTlstmMIB 1 } 1428 snmpTlstmObjects OBJECT IDENTIFIER ::= { snmpTlstmMIB 2 } 1429 snmpTlstmConformance OBJECT IDENTIFIER ::= { snmpTlstmMIB 3 } 1431 -- ************************************************ 1432 -- snmpTlstmObjects - Objects 1433 -- ************************************************ 1435 snmpTLSTCPDomain OBJECT-IDENTITY 1436 STATUS current 1437 DESCRIPTION 1438 "The SNMP over TLS transport domain. The corresponding 1439 transport address is of type SnmpTLSAddress. 1441 The securityName prefix to be associated with the 1442 snmpTLSTCPDomain is 'tls'. This prefix may be used by 1443 security models or other components to identify which secure 1444 transport infrastructure authenticated a securityName." 1445 REFERENCE 1446 "RFC 2579: Textual Conventions for SMIv2" 1448 ::= { snmpDomains xx } 1450 -- RFC Ed.: replace xx with IANA-assigned number and 1451 -- remove this note 1453 -- RFC Ed.: replace 'tls' with the actual IANA assigned prefix string 1454 -- if 'tls' is not assigned to this document. 1456 snmpDTLSUDPDomain OBJECT-IDENTITY 1457 STATUS current 1458 DESCRIPTION 1459 "The SNMP over DTLS/UDP transport domain. The corresponding 1460 transport address is of type SnmpTLSAddress. 1462 The securityName prefix to be associated with the 1463 snmpDTLSUDPDomain is 'dtls'. This prefix may be used by 1464 security models or other components to identify which secure 1465 transport infrastructure authenticated a securityName." 1466 REFERENCE 1467 "RFC 2579: Textual Conventions for SMIv2" 1469 ::= { snmpDomains yy } 1471 -- RFC Ed.: replace yy with IANA-assigned number and 1472 -- remove this note 1474 -- RFC Ed.: replace 'dtls' with the actual IANA assigned prefix string 1475 -- if 'dtls' is not assigned to this document. 1477 SnmpTLSAddress ::= TEXTUAL-CONVENTION 1478 DISPLAY-HINT "1a" 1479 STATUS current 1480 DESCRIPTION 1481 "Represents a IPv4 address, an IPv6 address or an US-ASCII 1482 encoded hostname and port number. 1484 An IPv4 address must be in dotted decimal format followed by a 1485 colon ':' (US-ASCII character 0x3A) and a decimal port number 1486 in US-ASCII. 1488 An IPv6 address must be a colon separated format (as described 1489 in I-D.ietf-6man-text-addr-representation), surrounded by 1490 square brackets ('[', US-ASCII character 0x5B, and ']', 1491 US-ASCII character 0x5D), followed by a colon ':' (US-ASCII 1492 character 0x3A) and a decimal port number in US-ASCII. 1494 A hostname is always in US-ASCII (as per RFC1033); 1495 internationalized hostnames are encoded in US-ASCII as domain 1496 names after transformation via the ToASCII operation specified 1497 in RFC 3490. The ToASCII operation MUST be performed with the 1498 UseSTD3ASCIIRules flag set. The hostname is followed by a 1499 colon ':' (US-ASCII character 0x3A) and a decimal port number 1500 in US-ASCII. The name SHOULD be fully qualified whenever 1501 possible. 1503 Values of this textual convention may not be directly usable 1504 as transport-layer addressing information, and may require 1505 run-time resolution. As such, applications that write them 1506 must be prepared for handling errors if such values are not 1507 supported, or cannot be resolved (if resolution occurs at the 1508 time of the management operation). 1510 The DESCRIPTION clause of TransportAddress objects that may 1511 have SnmpTLSAddress values must fully describe how (and 1512 when) such names are to be resolved to IP addresses and vice 1513 versa. 1515 This textual convention SHOULD NOT be used directly in object 1516 definitions since it restricts addresses to a specific 1517 format. However, if it is used, it MAY be used either on its 1518 own or in conjunction with TransportAddressType or 1519 TransportDomain as a pair. 1521 When this textual convention is used as a syntax of an index 1522 object, there may be issues with the limit of 128 1523 sub-identifiers specified in SMIv2 (STD 58). It is RECOMMENDED 1524 that all MIB documents using this textual convention make 1525 explicit any limitations on index component lengths that 1526 management software must observe. This may be done either by 1527 including SIZE constraints on the index components or by 1528 specifying applicable constraints in the conceptual row 1529 DESCRIPTION clause or in the surrounding documentation." 1530 REFERENCE 1531 "RFC 1033: DOMAIN ADMINISTRATORS OPERATIONS GUIDE 1532 RFC 3490: Internationalizing Domain Names in Applications 1533 I-D.ietf-6man-text-addr-representation: 1534 A Recommendation for IPv6 Address Text Representation 1535 " 1536 SYNTAX OCTET STRING (SIZE (1..255)) 1538 -- RFC Editor: if I-D.ietf-6man-text-addr-representation fails to get 1539 -- published then replace the reference to 1540 -- I-D.ietf-6man-text-addr-representation with a reference to 1541 -- "RFC3513: Internet Protocol Version 6 (IPv6) Addressing Architecture" 1542 -- instead. 1544 SnmpTLSFingerprint ::= TEXTUAL-CONVENTION 1545 DISPLAY-HINT "1x:254x" 1546 STATUS current 1547 DESCRIPTION 1548 "A fingerprint value that can be used to uniquely reference 1549 other data of potentially arbitrary length. 1551 A SnmpTLSFingerprint value is composed of a 1-octet hashing 1552 algorithm identifier followed by the fingerprint value. The 1553 octet value encoded is taken from the IANA TLS HashAlgorithm 1554 Registry (RFC5246). The remaining octets are filled using the 1555 results of the hashing algorithm. 1557 This TEXTUAL-CONVENTION allows for a zero-length (blank) 1558 SnmpTLSFingerprint value for use in tables where the 1559 fingerprint value may be optional. MIB definitions or 1560 implementations may refuse to accept a zero-length value as 1561 appropriate." 1562 REFERENCE "RFC 5246: The Transport Layer 1563 Security (TLS) Protocol Version 1.2 1564 http://www.iana.org/assignments/tls-parameters/ 1565 " 1566 SYNTAX OCTET STRING (SIZE (0..255)) 1568 -- Identities for use in the snmpTlstmCertToTSNTable 1569 snmpTlstmCertToTSNMIdentities OBJECT IDENTIFIER 1570 ::= { snmpTlstmIdentities 1 } 1572 snmpTlstmCertSpecified OBJECT-IDENTITY 1573 STATUS current 1574 DESCRIPTION "Directly specifies the tmSecurityName to be used for 1575 this certificate. The value of the tmSecurityName 1576 to use is specified in the snmpTlstmCertToTSNData 1577 column. The snmpTlstmCertToTSNData column must 1578 contain a non-zero length SnmpAdminString compliant 1579 value or the mapping described in this row must be 1580 considered a failure." 1581 ::= { snmpTlstmCertToTSNMIdentities 1 } 1583 snmpTlstmCertSANRFC822Name OBJECT-IDENTITY 1584 STATUS current 1585 DESCRIPTION "Maps a subjectAltName's rfc822Name to a 1586 tmSecurityName. The local part of the rfc822Name is 1587 passed unaltered but the host-part of the name must 1588 be passed in lower case. 1590 Example rfc822Name Field: FooBar@Example.COM 1591 is mapped to tmSecurityName: FooBar@example.com" 1592 ::= { snmpTlstmCertToTSNMIdentities 2 } 1594 snmpTlstmCertSANDNSName OBJECT-IDENTITY 1595 STATUS current 1596 DESCRIPTION "Maps a subjectAltName's dNSName to a 1597 tmSecurityName after first converting it to all 1598 lower case (note that RFC5280 does not specify 1599 converting to lower case so this involves an extra 1600 step)." 1601 REFERENCE "RFC5280 - Internet X.509 Public Key Infrastructure 1602 Certificate and Certificate Revocation 1603 List (CRL) Profile" 1604 ::= { snmpTlstmCertToTSNMIdentities 3 } 1606 snmpTlstmCertSANIpAddress OBJECT-IDENTITY 1607 STATUS current 1608 DESCRIPTION "Maps a subjectAltName's iPAddress to a 1609 tmSecurityName by transforming the binary encoded 1610 address as follows: 1612 1) for IPv4 the value is converted into a decimal 1613 dotted quad address (e.g. '192.0.2.1') 1615 2) for IPv6 addresses the value is converted into a 1616 32-character all lowercase hexadecimal string 1617 without any colon separators. 1619 Note that the resulting length is the maximum 1620 length supported by the View-Based Access Control 1621 Model (VACM). Note that using both the Transport 1622 Security Model's support for transport prefixes 1623 (see the SNMP-TSM-MIB's 1624 snmpTsmConfigurationUsePrefix object for details) 1625 will result in securityName lengths that exceed 1626 what VACM can handle." 1627 ::= { snmpTlstmCertToTSNMIdentities 4 } 1629 snmpTlstmCertSANAny OBJECT-IDENTITY 1630 STATUS current 1631 DESCRIPTION "Maps any of the following fields using the 1632 corresponding mapping algorithms: 1634 |------------+----------------------------| 1635 | Type | Algorithm | 1636 |------------+----------------------------| 1637 | rfc822Name | snmpTlstmCertSANRFC822Name | 1638 | dNSName | snmpTlstmCertSANDNSName | 1639 | iPAddress | snmpTlstmCertSANIpAddress | 1640 |------------+----------------------------| 1642 The first matching subjectAltName value found in the 1643 certificate of the above types MUST be used when 1644 deriving the tmSecurityName. The mapping algorithm 1645 specified in the 'Algorithm' column MUST be used to 1646 derive the tmSecurityName." 1647 ::= { snmpTlstmCertToTSNMIdentities 5 } 1649 snmpTlstmCertCommonName OBJECT-IDENTITY 1650 STATUS current 1652 DESCRIPTION "Maps a certificate's CommonName to a tmSecurityName 1653 after converting it to a UTF-8 encoding. The usage 1654 of CommonNames is deprecated and users are 1655 encouraged to use subjectAltName mapping methods 1656 instead." 1657 ::= { snmpTlstmCertToTSNMIdentities 6 } 1659 -- The snmpTlstmSession Group 1661 snmpTlstmSession OBJECT IDENTIFIER ::= { snmpTlstmObjects 1 } 1663 snmpTlstmSessionOpens OBJECT-TYPE 1664 SYNTAX Counter32 1665 MAX-ACCESS read-only 1666 STATUS current 1667 DESCRIPTION 1668 "The number of times an openSession() request has been executed 1669 as an (D)TLS client, regardless of whether it succeeded or 1670 failed." 1671 ::= { snmpTlstmSession 1 } 1673 snmpTlstmSessionClientCloses OBJECT-TYPE 1674 SYNTAX Counter32 1675 MAX-ACCESS read-only 1676 STATUS current 1677 DESCRIPTION 1678 "The number of times a closeSession() request has been 1679 executed as an (D)TLS client, regardless of whether it 1680 succeeded or failed." 1681 ::= { snmpTlstmSession 2 } 1683 snmpTlstmSessionOpenErrors OBJECT-TYPE 1684 SYNTAX Counter32 1685 MAX-ACCESS read-only 1686 STATUS current 1687 DESCRIPTION 1688 "The number of times an openSession() request failed to open a 1689 session as a (D)TLS client, for any reason." 1690 ::= { snmpTlstmSession 3 } 1692 snmpTlstmSessionAccepts OBJECT-TYPE 1693 SYNTAX Counter32 1694 MAX-ACCESS read-only 1695 STATUS current 1696 DESCRIPTION 1697 "The number of times a (D)TLS server has accepted a new 1698 connection from a client and has received at least one SNMP 1699 message through it." 1700 ::= { snmpTlstmSession 4 } 1702 snmpTlstmSessionServerCloses OBJECT-TYPE 1703 SYNTAX Counter32 1704 MAX-ACCESS read-only 1705 STATUS current 1706 DESCRIPTION 1707 "The number of times a closeSession() request has been 1708 executed as an (D)TLS server, regardless of whether it 1709 succeeded or failed." 1710 ::= { snmpTlstmSession 5 } 1712 snmpTlstmSessionNoSessions OBJECT-TYPE 1713 SYNTAX Counter32 1714 MAX-ACCESS read-only 1715 STATUS current 1716 DESCRIPTION 1717 "The number of times an outgoing message was dropped because 1718 the session associated with the passed tmStateReference was no 1719 longer (or was never) available." 1720 ::= { snmpTlstmSession 6 } 1722 snmpTlstmSessionInvalidClientCertificates OBJECT-TYPE 1723 SYNTAX Counter32 1724 MAX-ACCESS read-only 1725 STATUS current 1726 DESCRIPTION 1727 "The number of times an incoming session was not established 1728 on an (D)TLS server because the presented client certificate 1729 was invalid. Reasons for invalidation include, but are not 1730 limited to, cryptographic validation failures or lack of a 1731 suitable mapping row in the snmpTlstmCertToTSNTable." 1732 ::= { snmpTlstmSession 7 } 1734 snmpTlstmSessionUnknownServerCertificate OBJECT-TYPE 1735 SYNTAX Counter32 1736 MAX-ACCESS read-only 1737 STATUS current 1738 DESCRIPTION 1739 "The number of times an outgoing session was not established 1740 on an (D)TLS client because the server certificate presented 1741 by a SNMP over (D)TLS server was invalid because no 1742 configured fingerprint or CA was acceptable to validate it. 1743 This may result because there was no entry in the 1744 snmpTlstmAddrTable or because no path could be found to a 1745 known certification authority." 1746 ::= { snmpTlstmSession 8 } 1748 snmpTlstmSessionInvalidServerCertificates OBJECT-TYPE 1749 SYNTAX Counter32 1750 MAX-ACCESS read-only 1751 STATUS current 1752 DESCRIPTION 1753 "The number of times an outgoing session was not established 1754 on an (D)TLS client because the server certificate presented 1755 by an SNMP over (D)TLS server could not be validated even if 1756 the fingerprint or expected validation path was known. I.E., 1757 a cryptographic validation error occurred during certificate 1758 validation processing. 1760 Reasons for invalidation include, but are not 1761 limited to, cryptographic validation failures." 1762 ::= { snmpTlstmSession 9 } 1764 snmpTlstmSessionInvalidCaches OBJECT-TYPE 1765 SYNTAX Counter32 1766 MAX-ACCESS read-only 1767 STATUS current 1768 DESCRIPTION 1769 "The number of outgoing messages dropped because the 1770 tmStateReference referred to an invalid cache." 1771 ::= { snmpTlstmSession 10 } 1773 -- Configuration Objects 1775 snmpTlstmConfig OBJECT IDENTIFIER ::= { snmpTlstmObjects 2 } 1777 -- Certificate mapping 1779 snmpTlstmCertificateMapping OBJECT IDENTIFIER ::= { snmpTlstmConfig 1 } 1781 snmpTlstmCertToTSNCount OBJECT-TYPE 1782 SYNTAX Gauge32 1783 MAX-ACCESS read-only 1784 STATUS current 1785 DESCRIPTION 1786 "A count of the number of entries in the 1787 snmpTlstmCertToTSNTable" 1788 ::= { snmpTlstmCertificateMapping 1 } 1790 snmpTlstmCertToTSNTableLastChanged OBJECT-TYPE 1791 SYNTAX TimeStamp 1792 MAX-ACCESS read-only 1793 STATUS current 1794 DESCRIPTION 1795 "The value of sysUpTime.0 when the snmpTlstmCertToTSNTable was 1796 last modified through any means, or 0 if it has not been 1797 modified since the command responder was started." 1798 ::= { snmpTlstmCertificateMapping 2 } 1800 snmpTlstmCertToTSNTable OBJECT-TYPE 1801 SYNTAX SEQUENCE OF SnmpTlstmCertToTSNEntry 1802 MAX-ACCESS not-accessible 1803 STATUS current 1804 DESCRIPTION 1805 "This table is used by a (D)TLS server to map the (D)TLS 1806 client's presented X.509 certificate to a tmSecurityName. 1808 On an incoming (D)TLS/SNMP connection the client's presented 1809 certificate must either be validated based on an established 1810 trust anchor, or it must directly match a fingerprint in this 1811 table. This table does not provide any mechanisms for 1812 configuring the trust anchors; the transfer of any needed 1813 trusted certificates for path validation is expected to occur 1814 through an out-of-band transfer. 1816 Once the certificate has been found acceptable (either by path 1817 validation or directly matching a fingerprint in this table), 1818 this table is consulted to determine the appropriate 1819 tmSecurityName to identify with the remote connection. This 1820 is done by considering each active row from this table in 1821 prioritized order according to its snmpTlstmCertToTSNID value. 1822 Each row's snmpTlstmCertToTSNFingerprint value determines 1823 whether the row is a match for the incoming connection: 1825 1) If the row's snmpTlstmCertToTSNFingerprint value 1826 identifies the presented certificate then consider the 1827 row as a successful match. 1829 2) If the row's snmpTlstmCertToTSNFingerprint value 1830 identifies a locally held copy of a trusted CA 1831 certificate and that CA certificate was used to 1832 validate the path to the presented certificate then 1833 consider the row as a successful match. 1835 Once a matching row has been found, the 1836 snmpTlstmCertToTSNMapType value can be used to determine how 1837 the tmSecurityName to associate with the session should be 1838 determined. See the snmpTlstmCertToTSNMapType column's 1839 DESCRIPTION for details on determining the tmSecurityName 1840 value. If it is impossible to determine a tmSecurityName from 1841 the row's data combined with the data presented in the 1842 certificate then additional rows MUST be searched looking for 1843 another potential match. If a resulting tmSecurityName mapped 1844 from a given row is not compatible with the needed 1845 requirements of a tmSecurityName (e.g., VACM imposes a 1846 32-octet-maximum length and the certificate derived 1847 securityName could be longer) then it must be considered an 1848 invalid match and additional rows MUST be searched looking for 1849 another potential match. 1851 If no matching and valid row can be found, the connection MUST 1852 be closed and SNMP messages MUST NOT be accepted over it. 1854 Missing values of snmpTlstmCertToTSNID are acceptable and 1855 implementations should continue to the next highest numbered 1856 row. It is recommended that administrators skip index values 1857 to leave room for the insertion of future rows (E.G., use values 1858 of 10 and 20 when creating initial rows). 1860 Users are encouraged to make use of certificates with 1861 subjectAltName fields that can be used as tmSecurityNames so 1862 that a single root CA certificate can allow all child 1863 certificate's subjectAltName to map directly to a 1864 tmSecurityName via a 1:1 transformation. However, this table 1865 is flexible to allow for situations where existing deployed 1866 certificate infrastructures do not provide adequate 1867 subjectAltName values for use as tmSecurityNames. 1868 Certificates may also be mapped to tmSecurityNames using the 1869 CommonName portion of the Subject field. However, the usage 1870 of the CommonName field is deprecated and thus this usage is 1871 NOT RECOMMENDED. Direct mapping from each individual 1872 certificate fingerprint to a tmSecurityName is also possible 1873 but requires one entry in the table per tmSecurityName and 1874 requires more management operations to completely configure a 1875 device." 1876 ::= { snmpTlstmCertificateMapping 3 } 1878 snmpTlstmCertToTSNEntry OBJECT-TYPE 1879 SYNTAX SnmpTlstmCertToTSNEntry 1880 MAX-ACCESS not-accessible 1881 STATUS current 1882 DESCRIPTION 1883 "A row in the snmpTlstmCertToTSNTable that specifies a mapping 1884 for an incoming (D)TLS certificate to a tmSecurityName to use 1885 for a connection." 1886 INDEX { snmpTlstmCertToTSNID } 1887 ::= { snmpTlstmCertToTSNTable 1 } 1889 SnmpTlstmCertToTSNEntry ::= SEQUENCE { 1890 snmpTlstmCertToTSNID Unsigned32, 1891 snmpTlstmCertToTSNFingerprint SnmpTLSFingerprint, 1892 snmpTlstmCertToTSNMapType AutonomousType, 1893 snmpTlstmCertToTSNData OCTET STRING, 1894 snmpTlstmCertToTSNStorageType StorageType, 1895 snmpTlstmCertToTSNRowStatus RowStatus 1896 } 1898 snmpTlstmCertToTSNID OBJECT-TYPE 1899 SYNTAX Unsigned32 (1..4294967295) 1900 MAX-ACCESS not-accessible 1901 STATUS current 1902 DESCRIPTION 1903 "A unique, prioritized index for the given entry. Lower 1904 numbers indicate a higher priority." 1905 ::= { snmpTlstmCertToTSNEntry 1 } 1907 snmpTlstmCertToTSNFingerprint OBJECT-TYPE 1908 SYNTAX SnmpTLSFingerprint (SIZE(1..255)) 1909 MAX-ACCESS read-create 1910 STATUS current 1911 DESCRIPTION 1912 "A cryptographic hash of a X.509 certificate. The results of 1913 a successful matching fingerprint to either the trusted CA in 1914 the certificate validation path or to the certificate itself 1915 is dictated by the snmpTlstmCertToTSNMapType column." 1916 ::= { snmpTlstmCertToTSNEntry 2 } 1918 snmpTlstmCertToTSNMapType OBJECT-TYPE 1919 SYNTAX AutonomousType 1920 MAX-ACCESS read-create 1921 STATUS current 1922 DESCRIPTION 1923 "Specifies the mapping type for deriving a tmSecurityName from 1924 a certificate. Details for mapping of a particular type SHALL 1925 be specified in the DESCRIPTION clause of the OBJECT-IDENTITY 1926 that describes the mapping. If a mapping succeeds it will 1927 return a tmSecurityName for use by the TLSTM model and 1928 processing stops. 1930 If the resulting mapped value is not compatible with the 1931 needed requirements of a tmSecurityName (e.g., VACM imposes a 1932 32-octet-maximum length and the certificate derived 1933 securityName could be longer) then future rows MUST be 1934 searched for additional snmpTlstmCertToTSNFingerprint matches 1935 to look for a mapping that succeeds. 1937 Suitable values for assigning to this object that are defined 1938 within the SNMP-TLS-TM-MIB can be found in the 1939 snmpTlstmCertToTSNMIdentities portion of the MIB tree." 1940 DEFVAL { snmpTlstmCertSpecified } 1941 ::= { snmpTlstmCertToTSNEntry 3 } 1943 snmpTlstmCertToTSNData OBJECT-TYPE 1944 SYNTAX OCTET STRING (SIZE(0..1024)) 1945 MAX-ACCESS read-create 1946 STATUS current 1947 DESCRIPTION 1948 "Auxiliary data used as optional configuration information for 1949 a given mapping specified by the snmpTlstmCertToTSNMapType 1950 column. Only some mapping systems will make use of this 1951 column. The value in this column MUST be ignored for any 1952 mapping type that does not require data present in this 1953 column." 1954 DEFVAL { "" } 1955 ::= { snmpTlstmCertToTSNEntry 4 } 1957 snmpTlstmCertToTSNStorageType OBJECT-TYPE 1958 SYNTAX StorageType 1959 MAX-ACCESS read-create 1960 STATUS current 1961 DESCRIPTION 1962 "The storage type for this conceptual row. Conceptual rows 1963 having the value 'permanent' need not allow write-access to 1964 any columnar objects in the row." 1965 DEFVAL { nonVolatile } 1966 ::= { snmpTlstmCertToTSNEntry 5 } 1968 snmpTlstmCertToTSNRowStatus OBJECT-TYPE 1969 SYNTAX RowStatus 1970 MAX-ACCESS read-create 1971 STATUS current 1972 DESCRIPTION 1973 "The status of this conceptual row. This object may be used 1974 to create or remove rows from this table. 1976 To create a row in this table, an administrator must set this 1977 object to either createAndGo(4) or createAndWait(5). 1979 Until instances of all corresponding columns are appropriately 1980 configured, the value of the corresponding instance of the 1981 snmpTlstmParamsRowStatus column is notReady(3). 1983 In particular, a newly created row cannot be made active until 1984 the corresponding snmpTlstmCertToTSNFingerprint, 1985 snmpTlstmCertToTSNMapType, and snmpTlstmCertToTSNData columns 1986 have been set. 1988 The following objects may not be modified while the 1989 value of this object is active(1): 1990 - snmpTlstmCertToTSNFingerprint 1991 - snmpTlstmCertToTSNMapType 1992 - snmpTlstmCertToTSNData 1993 An attempt to set these objects while the value of 1994 snmpTlstmParamsRowStatus is active(1) will result in 1995 an inconsistentValue error." 1996 ::= { snmpTlstmCertToTSNEntry 6 } 1998 -- Maps tmSecurityNames to certificates for use by the SNMP-TARGET-MIB 1999 snmpTlstmParamsCount OBJECT-TYPE 2000 SYNTAX Gauge32 2001 MAX-ACCESS read-only 2002 STATUS current 2003 DESCRIPTION 2004 "A count of the number of entries in the snmpTlstmParamsTable" 2005 ::= { snmpTlstmCertificateMapping 4 } 2007 snmpTlstmParamsTableLastChanged OBJECT-TYPE 2008 SYNTAX TimeStamp 2009 MAX-ACCESS read-only 2010 STATUS current 2011 DESCRIPTION 2012 "The value of sysUpTime.0 when the snmpTlstmParamsTable 2013 was last modified through any means, or 0 if it has not been 2014 modified since the command responder was started." 2015 ::= { snmpTlstmCertificateMapping 5 } 2017 snmpTlstmParamsTable OBJECT-TYPE 2018 SYNTAX SEQUENCE OF SnmpTlstmParamsEntry 2019 MAX-ACCESS not-accessible 2020 STATUS current 2021 DESCRIPTION 2022 "This table is used by a (D)TLS client when a (D)TLS 2023 connection is being set up using an entry in the 2024 SNMP-TARGET-MIB. It extends the SNMP-TARGET-MIB's 2025 snmpTargetParamsTable with a fingerprint of a certificate to 2026 use when establishing such a (D)TLS connection." 2027 ::= { snmpTlstmCertificateMapping 6 } 2029 snmpTlstmParamsEntry OBJECT-TYPE 2030 SYNTAX SnmpTlstmParamsEntry 2031 MAX-ACCESS not-accessible 2032 STATUS current 2033 DESCRIPTION 2034 "A conceptual row containing a fingerprint hash of a locally 2035 held certificate for a given snmpTargetParamsEntry. The 2036 values in this row should be ignored if the connection that 2037 needs to be established, as indicated by the SNMP-TARGET-MIB 2038 infrastructure, is not a certificate and (D)TLS based 2039 connection. The connection SHOULD NOT be established if the 2040 certificate fingerprint stored in this entry does not point to 2041 a valid locally held certificate or if it points to an 2042 unusable certificate (such as might happen when the 2043 certificate's expiration date has been reached)." 2044 INDEX { IMPLIED snmpTargetParamsName } 2045 ::= { snmpTlstmParamsTable 1 } 2047 SnmpTlstmParamsEntry ::= SEQUENCE { 2048 snmpTlstmParamsClientFingerprint SnmpTLSFingerprint, 2049 snmpTlstmParamsStorageType StorageType, 2050 snmpTlstmParamsRowStatus RowStatus 2051 } 2053 snmpTlstmParamsClientFingerprint OBJECT-TYPE 2054 SYNTAX SnmpTLSFingerprint 2055 MAX-ACCESS read-create 2056 STATUS current 2057 DESCRIPTION 2058 "This object stores the hash of the public portion of a 2059 locally held X.509 certificate. The X.509 certificate, its 2060 public key, and the corresponding private key will be used 2061 when initiating a (D)TLS connection as a (D)TLS client." 2062 ::= { snmpTlstmParamsEntry 1 } 2064 snmpTlstmParamsStorageType OBJECT-TYPE 2065 SYNTAX StorageType 2066 MAX-ACCESS read-create 2067 STATUS current 2068 DESCRIPTION 2069 "The storage type for this conceptual row. Conceptual rows 2070 having the value 'permanent' need not allow write-access to 2071 any columnar objects in the row." 2072 DEFVAL { nonVolatile } 2073 ::= { snmpTlstmParamsEntry 2 } 2075 snmpTlstmParamsRowStatus OBJECT-TYPE 2076 SYNTAX RowStatus 2077 MAX-ACCESS read-create 2078 STATUS current 2079 DESCRIPTION 2080 "The status of this conceptual row. This object may be used 2081 to create or remove rows from this table. 2083 To create a row in this table, an administrator must set this 2084 object to either createAndGo(4) or createAndWait(5). 2086 Until instances of all corresponding columns are appropriately 2087 configured, the value of the corresponding instance of the 2088 snmpTlstmParamsRowStatus column is notReady(3). 2090 In particular, a newly created row cannot be made active until 2091 the corresponding snmpTlstmParamsClientFingerprint column has 2092 been set. 2094 The snmpTlstmParamsClientFingerprint object may not be modified 2095 while the value of this object is active(1). 2097 An attempt to set these objects while the value of 2098 snmpTlstmParamsRowStatus is active(1) will result in 2099 an inconsistentValue error." 2100 ::= { snmpTlstmParamsEntry 3 } 2102 snmpTlstmAddrCount OBJECT-TYPE 2103 SYNTAX Gauge32 2104 MAX-ACCESS read-only 2105 STATUS current 2106 DESCRIPTION 2107 "A count of the number of entries in the snmpTlstmAddrTable" 2108 ::= { snmpTlstmCertificateMapping 7 } 2110 snmpTlstmAddrTableLastChanged OBJECT-TYPE 2111 SYNTAX TimeStamp 2112 MAX-ACCESS read-only 2113 STATUS current 2114 DESCRIPTION 2115 "The value of sysUpTime.0 when the snmpTlstmAddrTable 2116 was last modified through any means, or 0 if it has not been 2117 modified since the command responder was started." 2118 ::= { snmpTlstmCertificateMapping 8 } 2120 snmpTlstmAddrTable OBJECT-TYPE 2121 SYNTAX SEQUENCE OF SnmpTlstmAddrEntry 2122 MAX-ACCESS not-accessible 2123 STATUS current 2124 DESCRIPTION 2125 "This table is used by a (D)TLS client when a (D)TLS 2126 connection is being set up using an entry in the 2127 SNMP-TARGET-MIB. It extends the SNMP-TARGET-MIB's 2128 snmpTargetAddrTable so that the client can verify that the 2129 correct server has been reached. This verification can use 2130 either a certificate fingerprint, or an identity 2131 authenticated via certification path validation. 2133 If there is an active row in this table corresponding to the 2134 entry in the SNMP-TARGET-MIB that was used to establish the 2135 connection, and the row's snmpTlstmAddrServerFingerprint 2136 column has non-empty value, then the server's presented 2137 certificate is compared with the 2138 snmpTlstmAddrServerFingerprint value (and the 2139 snmpTlstmAddrServerIdentity column is ignored). If the 2140 fingerprint matches, the verification has succeeded. If the 2141 fingerprint does not match then the connection MUST be 2142 closed. 2144 If the server's presented certificate has passed 2145 certification path validation [RFC5280] to a configured 2146 trust anchor, and an active row exists with a zero-length 2147 snmpTlstmAddrServerFingerprint value, then the 2148 snmpTlstmAddrServerIdentity column contains the expected 2149 host name. This expected host name is then compared against 2150 the server's certificate as follows: 2152 - Implementations MUST support matching the expected host 2153 name against a dNSName in the subjectAltName extension 2154 field and MAY support checking the name against the 2155 CommonName portion of the subject distinguished name. 2157 - The '*' (ASCII 0x2a) wildcard character is allowed in the 2158 dNSName of the subjectAltName extension (and in common 2159 name, if used to store the host name), but only as the 2160 left-most (least significant) DNS label in that value. 2161 This wildcard matches any left-most DNS label in the 2162 server name. That is, the subject *.example.com matches 2163 the server names a.example.com and b.example.com, but does 2164 not match example.com or a.b.example.com. Implementations 2165 MUST support wildcards in certificates as specified above, 2166 but MAY provide a configuration option to disable them. 2168 - If the locally configured name is an internationalized 2169 domain name, conforming implementations MUST convert it to 2170 the ASCII Compatible Encoding (ACE) format for performing 2171 comparisons, as specified in Section 7 of [RFC5280]. 2173 If the expected host name fails these conditions then the 2174 connection MUST be closed. 2176 If there is no row in this table corresponding to the entry 2177 in the SNMP-TARGET-MIB and the server can be authorized by 2178 another, implementation dependent means, then the connection 2179 MAY still proceed." 2181 ::= { snmpTlstmCertificateMapping 9 } 2183 snmpTlstmAddrEntry OBJECT-TYPE 2184 SYNTAX SnmpTlstmAddrEntry 2185 MAX-ACCESS not-accessible 2186 STATUS current 2187 DESCRIPTION 2188 "A conceptual row containing a copy of a certificate's 2189 fingerprint for a given snmpTargetAddrEntry. The values in 2190 this row should be ignored if the connection that needs to be 2191 established, as indicated by the SNMP-TARGET-MIB 2192 infrastructure, is not a (D)TLS based connection. If an 2193 snmpTlstmAddrEntry exists for a given snmpTargetAddrEntry then 2194 the presented server certificate MUST match or the connection 2195 MUST NOT be established. If a row in this table does not 2196 exist to match a snmpTargetAddrEntry row then the connection 2197 SHOULD still proceed if some other certificate validation path 2198 algorithm (e.g. RFC5280) can be used." 2199 INDEX { IMPLIED snmpTargetAddrName } 2200 ::= { snmpTlstmAddrTable 1 } 2202 SnmpTlstmAddrEntry ::= SEQUENCE { 2203 snmpTlstmAddrServerFingerprint SnmpTLSFingerprint, 2204 snmpTlstmAddrServerIdentity SnmpAdminString, 2205 snmpTlstmAddrStorageType StorageType, 2206 snmpTlstmAddrRowStatus RowStatus 2207 } 2209 snmpTlstmAddrServerFingerprint OBJECT-TYPE 2210 SYNTAX SnmpTLSFingerprint 2211 MAX-ACCESS read-create 2212 STATUS current 2213 DESCRIPTION 2214 "A cryptographic hash of a public X.509 certificate. This 2215 object should store the hash of the public X.509 certificate 2216 that the remote server should present during the (D)TLS 2217 connection setup. The fingerprint of the presented 2218 certificate and this hash value MUST match exactly or the 2219 connection MUST NOT be established." 2220 DEFVAL { "" } 2221 ::= { snmpTlstmAddrEntry 1 } 2223 snmpTlstmAddrServerIdentity OBJECT-TYPE 2224 SYNTAX SnmpAdminString 2225 MAX-ACCESS read-create 2226 STATUS current 2227 DESCRIPTION 2228 "The reference identity to check against the identity 2229 presented by the remote system." 2230 DEFVAL { "" } 2231 ::= { snmpTlstmAddrEntry 2 } 2233 snmpTlstmAddrStorageType OBJECT-TYPE 2234 SYNTAX StorageType 2235 MAX-ACCESS read-create 2236 STATUS current 2237 DESCRIPTION 2238 "The storage type for this conceptual row. Conceptual rows 2239 having the value 'permanent' need not allow write-access to 2240 any columnar objects in the row." 2241 DEFVAL { nonVolatile } 2242 ::= { snmpTlstmAddrEntry 3 } 2244 snmpTlstmAddrRowStatus OBJECT-TYPE 2245 SYNTAX RowStatus 2246 MAX-ACCESS read-create 2247 STATUS current 2248 DESCRIPTION 2249 "The status of this conceptual row. This object may be used 2250 to create or remove rows from this table. 2252 To create a row in this table, an administrator must set this 2253 object to either createAndGo(4) or createAndWait(5). 2255 Until instances of all corresponding columns are 2256 appropriately configured, the value of the 2257 corresponding instance of the snmpTlstmAddrRowStatus 2258 column is notReady(3). 2260 In particular, a newly created row cannot be made active until 2261 the corresponding snmpTlstmAddrServerFingerprint column has been 2262 set. 2264 Rows MUST NOT be active if the snmpTlstmAddrServerFingerprint 2265 column is blank and the snmpTlstmAddrServerIdentity is set to 2266 '*' since this would insecurely accept any presented 2267 certificate. 2269 The snmpTlstmAddrServerFingerprint object may not be modified 2270 while the value of this object is active(1). 2272 An attempt to set these objects while the value of 2273 snmpTlstmAddrRowStatus is active(1) will result in 2274 an inconsistentValue error." 2275 ::= { snmpTlstmAddrEntry 4 } 2277 -- ************************************************ 2278 -- snmpTlstmNotifications - Notifications Information 2279 -- ************************************************ 2281 snmpTlstmServerCertificateUnknown NOTIFICATION-TYPE 2282 OBJECTS { snmpTlstmSessionUnknownServerCertificate } 2283 STATUS current 2284 DESCRIPTION 2285 "Notification that the server certificate presented by a SNMP 2286 over (D)TLS server was invalid because no configured 2287 fingerprint or CA was acceptable to validate it. This may be 2288 because there was no entry in the snmpTlstmAddrTable or 2289 because no path could be found to known certificate 2290 authority. 2292 To avoid notification loops, this notification MUST NOT be 2293 sent to servers that themselves have triggered the 2294 notification." 2295 ::= { snmpTlstmNotifications 1 } 2297 snmpTlstmServerInvalidCertificate NOTIFICATION-TYPE 2298 OBJECTS { snmpTlstmAddrServerFingerprint, 2299 snmpTlstmSessionInvalidServerCertificates} 2300 STATUS current 2301 DESCRIPTION 2302 "Notification that the server certificate presented by an SNMP 2303 over (D)TLS server could not be validated even if the 2304 fingerprint or expected validation path was known. I.E., a 2305 cryptographic validation error occurred during certificate 2306 validation processing. 2308 To avoid notification loops, this notification MUST NOT be 2309 sent to servers that themselves have triggered the 2310 notification." 2311 ::= { snmpTlstmNotifications 2 } 2313 -- ************************************************ 2314 -- snmpTlstmCompliances - Conformance Information 2315 -- ************************************************ 2317 snmpTlstmCompliances OBJECT IDENTIFIER ::= { snmpTlstmConformance 1 } 2319 snmpTlstmGroups OBJECT IDENTIFIER ::= { snmpTlstmConformance 2 } 2321 -- ************************************************ 2322 -- Compliance statements 2323 -- ************************************************ 2325 snmpTlstmCompliance MODULE-COMPLIANCE 2326 STATUS current 2327 DESCRIPTION 2328 "The compliance statement for SNMP engines that support the 2329 SNMP-TLS-TM-MIB" 2331 MODULE 2332 MANDATORY-GROUPS { snmpTlstmStatsGroup, 2333 snmpTlstmIncomingGroup, 2334 snmpTlstmOutgoingGroup, 2335 snmpTlstmNotificationGroup } 2336 ::= { snmpTlstmCompliances 1 } 2338 -- ************************************************ 2339 -- Units of conformance 2340 -- ************************************************ 2341 snmpTlstmStatsGroup OBJECT-GROUP 2342 OBJECTS { 2343 snmpTlstmSessionOpens, 2344 snmpTlstmSessionClientCloses, 2345 snmpTlstmSessionOpenErrors, 2346 snmpTlstmSessionAccepts, 2347 snmpTlstmSessionServerCloses, 2348 snmpTlstmSessionNoSessions, 2349 snmpTlstmSessionInvalidClientCertificates, 2350 snmpTlstmSessionUnknownServerCertificate, 2351 snmpTlstmSessionInvalidServerCertificates, 2352 snmpTlstmSessionInvalidCaches 2353 } 2354 STATUS current 2355 DESCRIPTION 2356 "A collection of objects for maintaining 2357 statistical information of an SNMP engine which 2358 implements the SNMP TLS Transport Model." 2359 ::= { snmpTlstmGroups 1 } 2361 snmpTlstmIncomingGroup OBJECT-GROUP 2362 OBJECTS { 2363 snmpTlstmCertToTSNCount, 2364 snmpTlstmCertToTSNTableLastChanged, 2365 snmpTlstmCertToTSNFingerprint, 2366 snmpTlstmCertToTSNMapType, 2367 snmpTlstmCertToTSNData, 2368 snmpTlstmCertToTSNStorageType, 2369 snmpTlstmCertToTSNRowStatus 2370 } 2371 STATUS current 2372 DESCRIPTION 2373 "A collection of objects for maintaining 2374 incoming connection certificate mappings to 2375 tmSecurityNames of an SNMP engine which implements the 2376 SNMP TLS Transport Model." 2377 ::= { snmpTlstmGroups 2 } 2379 snmpTlstmOutgoingGroup OBJECT-GROUP 2380 OBJECTS { 2381 snmpTlstmParamsCount, 2382 snmpTlstmParamsTableLastChanged, 2383 snmpTlstmParamsClientFingerprint, 2384 snmpTlstmParamsStorageType, 2385 snmpTlstmParamsRowStatus, 2386 snmpTlstmAddrCount, 2387 snmpTlstmAddrTableLastChanged, 2388 snmpTlstmAddrServerFingerprint, 2389 snmpTlstmAddrServerIdentity, 2390 snmpTlstmAddrStorageType, 2391 snmpTlstmAddrRowStatus 2392 } 2393 STATUS current 2394 DESCRIPTION 2395 "A collection of objects for maintaining 2396 outgoing connection certificates to use when opening 2397 connections as a result of SNMP-TARGET-MIB settings." 2398 ::= { snmpTlstmGroups 3 } 2400 snmpTlstmNotificationGroup NOTIFICATION-GROUP 2401 NOTIFICATIONS { 2402 snmpTlstmServerCertificateUnknown, 2403 snmpTlstmServerInvalidCertificate 2404 } 2405 STATUS current 2406 DESCRIPTION 2407 "Notifications" 2408 ::= { snmpTlstmGroups 4 } 2410 END 2412 8. Operational Considerations 2414 This section discusses various operational aspects of deploying 2415 TLSTM. 2417 8.1. Sessions 2419 A session is discussed throughout this document as meaning a security 2420 association between two TLSTM instances. State information for the 2421 sessions are maintained in each TLSTM implementation and this 2422 information is created and destroyed as sessions are opened and 2423 closed. A "broken" session (one side up and one side down) can 2424 result if one side of a session is brought down abruptly (i.e., 2425 reboot, power outage, etc.). Whenever possible, implementations 2426 SHOULD provide graceful session termination through the use of TLS 2427 disconnect messages. Implementations SHOULD also have a system in 2428 place for detecting "broken" sessions through the use of heartbeats 2429 [I-D.seggelmann-tls-dtls-heartbeat] or other detection mechanisms. 2431 Implementations SHOULD limit the lifetime of established sessions 2432 depending on the algorithms used for generation of the master session 2433 secret, the privacy and integrity algorithms used to protect 2434 messages, the environment of the session, the amount of data 2435 transferred, and the sensitivity of the data. 2437 8.2. Notification Receiver Credential Selection 2439 When an SNMP engine needs to establish an outgoing session for 2440 notifications, the snmpTargetParamsTable includes an entry for the 2441 snmpTargetParamsSecurityName of the target. Servers that wish to 2442 support multiple principals at a particular port SHOULD make use of 2443 the Server Name Indication extension defined in Section 3.1 of 2444 [RFC4366]. Without the Server Name Indication the receiving SNMP 2445 engine (Server) will not know which (D)TLS certificate to offer to 2446 the Client so that the tmSecurityName identity-authentication will be 2447 successful. 2449 Another solution is to maintain a one-to-one mapping between 2450 certificates and incoming ports for notification receivers. This can 2451 be handled at the notification originator by configuring the 2452 snmpTargetAddrTable (snmpTargetAddrTDomain and 2453 snmpTargetAddrTAddress) and requiring the receiving SNMP engine to 2454 monitor multiple incoming static ports based on which principals are 2455 capable of receiving notifications. 2457 Implementations MAY also choose to designate a single Notification 2458 Receiver Principal to receive all incoming notifications or select an 2459 implementation specific method of selecting a server certificate to 2460 present to clients. 2462 8.3. contextEngineID Discovery 2464 SNMPv3 requires that an application know the identifier 2465 (snmpEngineID) of the remote SNMP protocol engine in order to 2466 retrieve or manipulate objects maintained on the remote SNMP entity. 2468 [RFC5343] introduces a well-known localEngineID and a discovery 2469 mechanism that can be used to learn the snmpEngineID of a remote SNMP 2470 protocol engine. Implementations are RECOMMENDED to support and use 2471 the contextEngineID discovery mechanism defined in [RFC5343]. 2473 8.4. Transport Considerations 2475 This document defines how SNMP messages can be transmitted over the 2476 TLS and DTLS based protocols. Each of these protocols are 2477 additionally based on other transports (TCP and UDP). These two base 2478 protocols also have operational considerations that must be taken 2479 into consideration when selecting a (D)TLS based protocol to use such 2480 as its performance in degraded or limited networks. It is beyond the 2481 scope of this document to summarize the characteristics of these 2482 transport mechanisms. Please refer to the base protocol documents 2483 for details on messaging considerations with respect to MTU size, 2484 fragmentation, performance in lossy-networks, etc. 2486 9. Security Considerations 2488 This document describes a transport model that permits SNMP to 2489 utilize (D)TLS security services. The security threats and how the 2490 (D)TLS transport model mitigates these threats are covered in detail 2491 throughout this document. Security considerations for DTLS are 2492 covered in [RFC4347] and security considerations for TLS are 2493 described in Section 11 and Appendices D, E, and F of TLS 1.2 2494 [RFC5246]. When run over a connectionless transport such as UDP, 2495 DTLS is more vulnerable to denial of service attacks from spoofed IP 2496 addresses; see Section 4.2 for details how the cookie exchange is 2497 used to address this issue. 2499 9.1. Certificates, Authentication, and Authorization 2501 Implementations are responsible for providing a security certificate 2502 installation and configuration mechanism. Implementations SHOULD 2503 support certificate revocation lists. 2505 (D)TLS provides for authentication of the identity of both the (D)TLS 2506 server and the (D)TLS client. Access to MIB objects for the 2507 authenticated principal MUST be enforced by an access control 2508 subsystem (e.g. the VACM). 2510 Authentication of the command generator principal's identity is 2511 important for use with the SNMP access control subsystem to ensure 2512 that only authorized principals have access to potentially sensitive 2513 data. The authenticated identity of the command generator 2514 principal's certificate is mapped to an SNMP model-independent 2515 securityName for use with SNMP access control. 2517 The (D)TLS handshake only provides assurance that the certificate of 2518 the authenticated identity has been signed by an configured accepted 2519 certification authority. (D)TLS has no way to further authorize or 2520 reject access based on the authenticated identity. An Access Control 2521 Model (such as the VACM) provides access control and authorization of 2522 a command generator's requests to a command responder and a 2523 notification receiver's authorization to receive Notifications from a 2524 notification originator. However to avoid man-in-the-middle attacks 2525 both ends of the (D)TLS based connection MUST check the certificate 2526 presented by the other side against what was expected. For example, 2527 command generators must check that the command responder presented 2528 and authenticated itself with a X.509 certificate that was expected. 2529 Not doing so would allow an impostor, at a minimum, to present false 2530 data, receive sensitive information and/or provide a false belief 2531 that configuration was actually received and acted upon. 2532 Authenticating and verifying the identity of the (D)TLS server and 2533 the (D)TLS client for all operations ensures the authenticity of the 2534 SNMP engine that provides MIB data. 2536 The instructions found in the DESCRIPTION clause of the 2537 snmpTlstmCertToTSNTable object must be followed exactly. It is also 2538 important that the rows of the table be searched in prioritized order 2539 starting with the row containing the lowest numbered 2540 snmpTlstmCertToTSNID value. 2542 9.2. (D)TLS Security Considerations 2544 This section discusses security considerations specific to the usage 2545 of (D)TLS. 2547 9.2.1. TLS Version Requirements 2549 Implementations of TLS typically support multiple versions of the 2550 Transport Layer Security protocol as well as the older Secure Sockets 2551 Layer (SSL) protocol. Because of known security vulnerabilities, 2552 TLSTM clients and servers MUST NOT request, offer, or use SSL 2.0. 2553 See Appendix E.2 of [RFC5246] for further details. 2555 9.2.2. Perfect Forward Secrecy 2557 The use of Perfect Forward Secrecy is RECOMMENDED and can be provided 2558 by (D)TLS with appropriately selected cipher suites, as discussed in 2559 Appendix F of [RFC5246]. 2561 9.3. Use with SNMPv1/SNMPv2c Messages 2563 The SNMPv1 and SNMPv2c message processing described in [RFC3584] (BCP 2564 74) always selects the SNMPv1 or SNMPv2c Security Models, 2565 respectively. Both of these and the User-based Security Model 2566 typically used with SNMPv3 derive the securityName and securityLevel 2567 from the SNMP message received, even when the message was received 2568 over a secure transport. Access control decisions are therefore made 2569 based on the contents of the SNMP message, rather than using the 2570 authenticated identity and securityLevel provided by the TLS 2571 Transport Model. It is RECOMMENDED that only SNMPv3 messages using 2572 the Transport Security Model (TSM) or another secure-transport aware 2573 security model be sent over the TLSTM transport. 2575 Using a non-transport-aware Security Model with a secure Transport 2576 Model is NOT RECOMMENDED. See [RFC5590] Section 7.1 for additional 2577 details on the coexistence of security-aware transports and non- 2578 transport-aware security models. 2580 9.4. MIB Module Security 2582 There are a number of management objects defined in this MIB module 2583 with a MAX-ACCESS clause of read-write and/or read-create. Such 2584 objects may be considered sensitive or vulnerable in some network 2585 environments. The support for SET operations in a non-secure 2586 environment without proper protection can have a negative effect on 2587 network operations. These are the tables and objects and their 2588 sensitivity/vulnerability: 2590 o The snmpTlstmParamsTable can be used to change the outgoing X.509 2591 certificate used to establish a (D)TLS connection. Modification 2592 to objects in this table need to be adequately authenticated since 2593 modification to values in this table will have profound impacts to 2594 the security of outbound connections from the device. Since 2595 knowledge of authorization rules and certificate usage mechanisms 2596 may be considered sensitive, protection from disclosure of the 2597 SNMP traffic via encryption is also highly recommended. 2599 o The snmpTlstmAddrTable can be used to change the expectations of 2600 the certificates presented by a remote (D)TLS server. 2601 Modification to objects in this table need to be adequately 2602 authenticated since modification to values in this table will have 2603 profound impacts to the security of outbound connections from the 2604 device. Since knowledge of authorization rules and certificate 2605 usage mechanisms may be considered sensitive, protection from 2606 disclosure of the SNMP traffic via encryption is also highly 2607 recommended. 2609 o The snmpTlstmCertToTSNTable is used to specify the mapping of 2610 incoming X.509 certificates to tmSecurityNames which eventually 2611 get mapped to a SNMPv3 securityName. Modification to objects in 2612 this table need to be adequately authenticated since modification 2613 to values in this table will have profound impacts to the security 2614 of incoming connections to the device. Since knowledge of 2615 authorization rules and certificate usage mechanisms may be 2616 considered sensitive, protection from disclosure of the SNMP 2617 traffic via encryption is also highly recommended. When this 2618 table contains a significant number of rows it may affect the 2619 system performance when accepting new (D)TLS connections. 2621 Some of the readable objects in this MIB module (i.e., objects with a 2622 MAX-ACCESS other than not-accessible) may be considered sensitive or 2623 vulnerable in some network environments. It is thus important to 2624 control even GET and/or NOTIFY access to these objects and possibly 2625 to even encrypt the values of these objects when sending them over 2626 the network via SNMP. These are the tables and objects and their 2627 sensitivity/vulnerability: 2629 o This MIB contains a collection of counters that monitor the (D)TLS 2630 connections being established with a device. Since knowledge of 2631 connection and certificate usage mechanisms may be considered 2632 sensitive, protection from disclosure of the SNMP traffic via 2633 encryption is also highly recommended. 2635 SNMP versions prior to SNMPv3 did not include adequate security. 2636 Even if the network itself is secure (for example by using IPsec), 2637 even then, there is no control as to who on the secure network is 2638 allowed to access and GET/SET (read/change/create/delete) the objects 2639 in this MIB module. 2641 It is RECOMMENDED that implementers consider the security features as 2642 provided by the SNMPv3 framework (see [RFC3410], section 8), 2643 including full support for the SNMPv3 cryptographic mechanisms (for 2644 authentication and privacy). 2646 Further, deployment of SNMP versions prior to SNMPv3 is NOT 2647 RECOMMENDED. Instead, it is RECOMMENDED to deploy SNMPv3 and to 2648 enable cryptographic security. It is then a customer/operator 2649 responsibility to ensure that the SNMP entity giving access to an 2650 instance of this MIB module is properly configured to give access to 2651 the objects only to those principals (users) that have legitimate 2652 rights to indeed GET or SET (change/create/delete) them. 2654 10. IANA Considerations 2656 IANA is requested to assign: 2658 1. Two TCP/UDP port numbers from the "Registered Ports" range of the 2659 Port Numbers registry, with the following keywords (where TBD1 2660 and TBD2 correspond to the assigned port numbers): 2662 Keyword Decimal Description References 2663 ------- ------- ----------- ---------- 2664 snmptls TBD1/tcp SNMP-TLS [RFC-isms-dtls-tm] 2665 snmpdtls TBD1/udp SNMP-DTLS [RFC-isms-dtls-tm] 2666 snmptls-trap TBD2/tcp SNMP-Trap-TLS [RFC-isms-dtls-tm] 2667 snmpdtls-trap TBD2/udp SNMP-Trap-DTLS [RFC-isms-dtls-tm] 2669 These are the default ports for receipt of SNMP command messages 2670 (snmptls and snmpdtls) and SNMP notification messages (snmptls- 2671 trap and snmpdtls-trap) over a TLS Transport Model as defined in 2672 this document. 2674 2. An SMI number under snmpDomains for the snmpTLSTCPDomain object 2675 identifier, 2677 3. An SMI number under snmpDomains for the snmpDTLSUDPDomain object 2678 identifier, 2680 4. A SMI number under mib-2, for the MIB module in this document, 2682 5. "tls" as the corresponding prefix for the snmpTLSTCPDomain in the 2683 SNMP Transport Model registry, 2685 6. "dtls" as the corresponding prefix for the snmpDTLSUDPDomain in 2686 the SNMP Transport Model registry, 2688 RFC Editor's note: this section should be replaced with appropriate 2689 descriptive assignment text after IANA assignments are made and prior 2690 to publication. 2692 11. Acknowledgements 2694 This document closely follows and copies the Secure Shell Transport 2695 Model for SNMP documented by David Harrington and Joseph Salowey in 2696 [RFC5592]. 2698 This document was reviewed by the following people who helped provide 2699 useful comments (in alphabetical order): Andy Donati, Pasi Eronen, 2700 David Harrington, Jeffrey Hutzelman, Alan Luchuk, Michael Peck, Tom 2701 Petch, Randy Presuhn, Ray Purvis, Peter Saint-Andre, Joseph Salowey, 2702 Jurgen Schonwalder, Dave Shield, Robert Story. 2704 This work was supported in part by the United States Department of 2705 Defense. Large portions of this document are based on work by 2706 General Dynamics C4 Systems and the following individuals: Brian 2707 Baril, Kim Bryant, Dana Deluca, Dan Hanson, Tim Huemiller, John 2708 Holzhauer, Colin Hoogeboom, Dave Kornbau, Chris Knaian, Dan Knaul, 2709 Charles Limoges, Steve Moccaldi, Gerardo Orlando, and Brandon Yip. 2711 12. References 2713 12.1. Normative References 2715 [RFC1033] Lottor, M., "Domain administrators operations guide", 2716 RFC 1033, November 1987. 2718 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 2719 Requirement Levels", BCP 14, RFC 2119, March 1997. 2721 [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. 2722 Schoenwaelder, Ed., "Structure of Management Information 2723 Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. 2725 [RFC2579] McCloghrie, K., Ed., Perkins, D., Ed., and J. 2726 Schoenwaelder, Ed., "Textual Conventions for SMIv2", 2727 STD 58, RFC 2579, April 1999. 2729 [RFC2580] McCloghrie, K., Perkins, D., and J. Schoenwaelder, 2730 "Conformance Statements for SMIv2", STD 58, RFC 2580, 2731 April 1999. 2733 [RFC3411] Harrington, D., Presuhn, R., and B. Wijnen, "An 2734 Architecture for Describing Simple Network Management 2735 Protocol (SNMP) Management Frameworks", STD 62, RFC 3411, 2736 December 2002. 2738 [RFC3413] Levi, D., Meyer, P., and B. Stewart, "Simple Network 2739 Management Protocol (SNMP) Applications", STD 62, 2740 RFC 3413, December 2002. 2742 [RFC3414] Blumenthal, U. and B. Wijnen, "User-based Security Model 2743 (USM) for version 3 of the Simple Network Management 2744 Protocol (SNMPv3)", STD 62, RFC 3414, December 2002. 2746 [RFC3415] Wijnen, B., Presuhn, R., and K. McCloghrie, "View-based 2747 Access Control Model (VACM) for the Simple Network 2748 Management Protocol (SNMP)", STD 62, RFC 3415, 2749 December 2002. 2751 [RFC3418] Presuhn, R., "Management Information Base (MIB) for the 2752 Simple Network Management Protocol (SNMP)", STD 62, 2753 RFC 3418, December 2002. 2755 [RFC3490] Faltstrom, P., Hoffman, P., and A. Costello, 2756 "Internationalizing Domain Names in Applications (IDNA)", 2757 RFC 3490, March 2003. 2759 [RFC3584] Frye, R., Levi, D., Routhier, S., and B. Wijnen, 2760 "Coexistence between Version 1, Version 2, and Version 3 2761 of the Internet-standard Network Management Framework", 2762 BCP 74, RFC 3584, August 2003. 2764 [RFC4347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer 2765 Security", RFC 4347, April 2006. 2767 [RFC4366] Blake-Wilson, S., Nystrom, M., Hopwood, D., Mikkelsen, J., 2768 and T. Wright, "Transport Layer Security (TLS) 2769 Extensions", RFC 4366, April 2006. 2771 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 2772 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 2774 [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., 2775 Housley, R., and W. Polk, "Internet X.509 Public Key 2776 Infrastructure Certificate and Certificate Revocation List 2777 (CRL) Profile", RFC 5280, May 2008. 2779 [RFC5590] Harrington, D. and J. Schoenwaelder, "Transport Subsystem 2780 for the Simple Network Management Protocol (SNMP)", 2781 RFC 5590, June 2009. 2783 [RFC5591] Harrington, D. and W. Hardaker, "Transport Security Model 2784 for the Simple Network Management Protocol (SNMP)", 2785 RFC 5591, June 2009. 2787 [I-D.draft-ietf-6man-text-addr-representation] 2788 Kawamura, S. and M. Kawashima, "A Recommendation for IPv6 2789 Address Text Representation". 2791 12.2. Informative References 2793 [RFC3410] Case, J., Mundy, R., Partain, D., and B. Stewart, 2794 "Introduction and Applicability Statements for Internet- 2795 Standard Management Framework", RFC 3410, December 2002. 2797 [RFC5343] Schoenwaelder, J., "Simple Network Management Protocol 2798 (SNMP) Context EngineID Discovery", RFC 5343, 2799 September 2008. 2801 [RFC5592] Harrington, D., Salowey, J., and W. Hardaker, "Secure 2802 Shell Transport Model for the Simple Network Management 2803 Protocol (SNMP)", RFC 5592, June 2009. 2805 [I-D.seggelmann-tls-dtls-heartbeat] 2806 Seggelmann, R., Tuexen, M., and M. Williams, "Transport 2807 Layer Security and Datagram Transport Layer Security 2808 Heartbeat Extension". 2810 Appendix A. Target and Notification Configuration Example 2812 The following sections describe example configuration for the SNMP- 2813 TLS-TM-MIB, the SNMP-TARGET-MIB, the NOTIFICATION-MIB and the SNMP- 2814 VIEW-BASED-ACM-MIB. 2816 A.1. Configuring a Notification Originator 2818 The following row adds the "Joe Cool" user to the "administrators" 2819 group: 2821 vacmSecurityModel = 4 (TSM) 2822 vacmSecurityName = "Joe Cool" 2823 vacmGroupName = "administrators" 2824 vacmSecurityToGroupStorageType = 3 (nonVolatile) 2825 vacmSecurityToGroupStatus = 4 (createAndGo) 2827 The following row configures the snmpTlstmAddrTable to use 2828 certificate path validation and to require the remote notification 2829 receiver to present a certificate for the "server.example.org" 2830 identity. 2832 snmpTargetAddrName = "toNRAddr" 2833 snmpTlstmAddrServerFingerprint = "" 2834 snmpTlstmAddrServerIdentity = "server.example.org" 2835 snmpTlstmAddrStorageType = 3 (nonVolatile) 2836 snmpTlstmAddrRowStatus = 4 (createAndGo) 2838 The following row configures the snmpTargetAddrTable to send 2839 notifications using TLS/TCP to the snmptls-trap port at 192.0.2.1: 2841 snmpTargetAddrName = "toNRAddr" 2842 snmpTargetAddrTDomain = snmpTLSTCPDomain 2843 snmpTargetAddrTAddress = "192.0.2.1:XXXsnmptls-trap" 2844 snmpTargetAddrTimeout = 1500 2845 snmpTargetAddrRetryCount = 3 2846 snmpTargetAddrTagList = "toNRTag" 2847 snmpTargetAddrParams = "toNR" (MUST match above) 2848 snmpTargetAddrStorageType = 3 (nonVolatile) 2849 snmpTargetAddrColumnStatus = 4 (createAndGo) 2851 RFC Editor's note: replace the string "XXXsnmptls-trap" above with 2852 the appropriately assigned "snmptls-trap" port. 2854 The following row configures the snmpTargetParamsTable to send the 2855 notifications to "Joe Cool", using authPriv SNMPv3 notifications 2856 through the TransportSecurityModel [RFC5591]: 2858 snmpTargetParamsName = toNR 2859 snmpTargetParamsMPModel = SNMPv3 2860 snmpTargetParamsSecurityModel = 4 (TransportSecurityModel) 2861 snmpTargetParamsSecurityName = "Joe Cool" 2862 snmpTargetParamsSecurityLevel = 3 (authPriv) 2863 snmpTargetParamsStorageType = 3 (nonVolatile) 2864 snmpTargetParamsRowStatus = 4 (createAndGo0 2866 A.2. Configuring TLSTM to Utilize a Simple Derivation of tmSecurityName 2868 The following row configures the snmpTlstmCertToTSNTable to map a 2869 validated client certificate, referenced by the client's public X.509 2870 hash fingerprint, to a tmSecurityName using the subjectAltName 2871 component of the certificate. 2873 snmpTlstmCertToTSNID = 1 2874 (chosen by ordering preference) 2875 snmpTlstmCertToTSNFingerprint = HASH (appropriate fingerprint) 2876 snmpTlstmCertToTSNMapType = snmpTlstmCertSANAny 2877 snmpTlstmCertToTSNData = "" (not used) 2878 snmpTlstmCertToTSNStorageType = 3 (nonVolatile) 2879 snmpTlstmCertToTSNRowStatus = 4 (createAndGo) 2881 This type of configuration should only be used when the naming 2882 conventions of the (possibly multiple) certificate authorities are 2883 well understood, so two different principals cannot inadvertently be 2884 identified by the same derived tmSecurityName. 2886 A.3. Configuring TLSTM to Utilize Table-Driven Certificate Mapping 2888 The following row configures the snmpTlstmCertToTSNTable to map a 2889 validated client certificate, referenced by the client's public X.509 2890 hash fingerprint, to the directly specified tmSecurityName of "Joe 2891 Cool". 2893 snmpTlstmCertToTSNID = 1 2894 (chosen by ordering preference) 2895 snmpTlstmCertToTSNFingerprint = HASH (appropriate fingerprint) 2896 snmpTlstmCertToTSNMapType = snmpTlstmCertSpecified 2897 snmpTlstmCertToTSNSecurityName = "Joe Cool" 2898 snmpTlstmCertToTSNStorageType = 3 (nonVolatile) 2899 snmpTlstmCertToTSNRowStatus = 4 (createAndGo) 2901 Author's Address 2903 Wes Hardaker 2904 Sparta, Inc. 2905 P.O. Box 382 2906 Davis, CA 95617 2907 USA 2909 Phone: +1 530 792 1913 2910 Email: ietf@hardakers.net