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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-23) exists of draft-ietf-syslog-protocol-22 ** Obsolete normative reference: RFC 2831 (ref. '7') (Obsoleted by RFC 6331) -- Obsolete informational reference (is this intentional?): RFC 3164 (ref. '8') (Obsoleted by RFC 5424) Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 10 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. New 3 Internet-Draft 4 Obsoletes: 3195 (if approved) M. Rose 5 Intended status: Standards Track Dover Beach Consulting, Inc. 6 Expires: May 11, 2008 E. Lear 7 Cisco Systems 8 November 8, 2007 10 Reliable Delivery for syslog 11 draft-ietf-syslog-rfc3195bis-00 13 Status of this Memo 15 By submitting this Internet-Draft, each author represents that any 16 applicable patent or other IPR claims of which he or she is aware 17 have been or will be disclosed, and any of which he or she becomes 18 aware will be disclosed, in accordance with Section 6 of BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF), its areas, and its working groups. Note that 22 other groups may also distribute working documents as Internet- 23 Drafts. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 The list of current Internet-Drafts can be accessed at 31 http://www.ietf.org/ietf/1id-abstracts.txt. 33 The list of Internet-Draft Shadow Directories can be accessed at 34 http://www.ietf.org/shadow.html. 36 This Internet-Draft will expire on May 11, 2008. 38 Copyright Notice 40 Copyright (C) The IETF Trust (2007). 42 Abstract 44 The syslog protocol describes a number of service options related to 45 propagating event messages. This memo describes a mapping of the 46 syslog protocol to TCP connections, useful for reliable delivery of 47 event messages through the use of a BEEP profile. The earlier RAW 48 and COOKED BEEP syslog profiles are deprecated. The use of syslog 49 over BEEP provides robustness and security in message delivery that 50 is unavailable to the usual UDP-based syslog protocol, by providing 51 encryption and authentication over a connection-oriented protocol. 53 Table of Contents 55 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 56 2. The Model . . . . . . . . . . . . . . . . . . . . . . . . . . 4 57 3. The TARTARE Profile . . . . . . . . . . . . . . . . . . . . . 5 58 3.1. TARTARE Profile Overview . . . . . . . . . . . . . . . . . 5 59 3.2. TARTARE Profile Identification and Initialization . . . . 7 60 3.3. TARTARE Profile Message Syntax . . . . . . . . . . . . . . 8 61 3.4. TARTARE Profile Message Semantics . . . . . . . . . . . . 8 62 4. Additional Provisioning . . . . . . . . . . . . . . . . . . . 9 63 4.1. Message Authenticity . . . . . . . . . . . . . . . . . . . 9 64 4.2. Message Replay . . . . . . . . . . . . . . . . . . . . . . 9 65 4.3. Message Integrity . . . . . . . . . . . . . . . . . . . . 9 66 4.4. Message Observation . . . . . . . . . . . . . . . . . . . 9 67 4.5. Summary of Recommended Practices . . . . . . . . . . . . . 10 68 5. Registrations . . . . . . . . . . . . . . . . . . . . . . . . 11 69 5.1. Registration: The TARTARE Profile . . . . . . . . . . . . 11 70 6. Reply Codes . . . . . . . . . . . . . . . . . . . . . . . . . 12 71 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 72 7.1. Registration: BEEP Profile . . . . . . . . . . . . . . . . 13 73 7.2. Registration: The System (Well-Known) TCP port number 74 for syslog-conn . . . . . . . . . . . . . . . . . . . . . 13 75 8. Security Considerations . . . . . . . . . . . . . . . . . . . 14 76 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 77 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 78 10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 79 10.2. Informative References . . . . . . . . . . . . . . . . . . 16 80 Appendix A. Coexistence with old RAW and COOKED modes . . . . . . 17 81 Appendix B. Changes from RFC 3195 . . . . . . . . . . . . . . . . 18 82 Appendix C. To Do . . . . . . . . . . . . . . . . . . . . . . . . 19 83 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 84 Intellectual Property and Copyright Statements . . . . . . . . . . 21 86 1. Introduction 88 The syslog protocol [1] presents a spectrum of service options for 89 provisioning an event-based logging service over a network. Each 90 option has associated benefits and costs. Accordingly, the choice as 91 to what combination of options is provisioned is both an engineering 92 and administrative decision. This memo describes how to realize the 93 syslog protocol when reliable delivery is selected as a required 94 service. It is beyond the scope of this memo to argue for, or 95 against, the use of reliable delivery for the syslog protocol. 97 This memo is a revision of previous work [9]. Based on 98 implementation and deployment experience, and the expectation of new 99 work in the field, the principle changes to this document are these: 101 o Both the COOKED and the RAW profiles are deprecated. The COOKED 102 profile is deprecated because there has been no substantial 103 deployment and it is no longer consistent with the work done in 104 [1]. 106 o The RAW profile is reproduced as a new profile, TARTARE, that has 107 no length limitations. Removal of the 1024 octet limitation is 108 necessary for future worked in the area of "signed syslog". 109 Previous length limitations continue to apply to the deprecated 110 RAW and COOKED profiles. 112 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 113 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 114 document are to be interpreted as described in RFC 2119 [2]. 116 2. The Model 118 The reader is referred to [1] for the authoritative explanation of 119 the syslog model. What follows are issues relating to that model 120 that are specific to BEEP and this mapping. 122 It should be noted that a role of sender, relay, or collector is 123 relevant only to a particular BEEP channel (q.v., below). A single 124 server can serve as a sender, a relay, and a collector, all at once, 125 if so configured. It can even serve as a relay and a collector to 126 the same sender or device at the same time using different BEEP 127 channels over the same connection-oriented session; this might be 128 useful to collect status yet relay urgent error messages. 130 To provide reliable delivery when realizing the syslog protocol, this 131 memo defines a new BEEP profile. BEEP [3] is a generic application 132 protocol framework for connection-oriented, asynchronous 133 interactions. Within BEEP, features such as authentication, privacy, 134 and reliability through retransmission are provided. The new TARTARE 135 profile is designed to provide a high-performance, low-impact 136 footprint, using essentially the same format as the existing UDP- 137 based syslog service. 139 BEEP defines "transport mappings," specifying how BEEP messages are 140 carried over the underlying transport technologies. At the time of 141 this writing, only one such transport is defined, in [4], which 142 specifies BEEP over TCP. All transport mappings are required to 143 support enough reliability and sequencing to allow all BEEP messages 144 on a given channel to be delivered reliably and in order. Hence, the 145 TARTARE profile provides reliable delivery of messages. 147 Senders and relays MAY discover relays and collectors via the DNS SRV 148 algorithm [5]. If so configured, the service used is "syslog" and 149 the protocol used is "tcp". This allows for central administration 150 of addressing, fallback for failed relays and collectors, and static 151 load balancing. Security policies and hardware configurations may be 152 such that device configuration is more secure than the DNS server. 153 Hardware devices may be of such limited resources that DNS SRV access 154 is inappropriate. Firewalls and other restrictive routing mechanisms 155 may need to be dealt with before a reliable syslog connection can be 156 established. In these cases, DNS might not be the most appropriate 157 configuration mechanism. 159 3. The TARTARE Profile 161 3.1. TARTARE Profile Overview 163 The TARTARE profile is designed for minimal implementation effort, 164 high efficiency, and backwards compatibility. 166 It should be noted that even though the TARTARE profile uses the same 167 format for message payloads as the UDP version of syslog uses, 168 delivery is reliable. The TARTARE syslog profile is a profile of 169 BEEP [3], and BEEP guarantees ordered reliable delivery of messages 170 within each individual channel. 172 When the profile is started, no piggyback data is supplied. All BEEP 173 messages in the TARTARE profile are specified as having a MIME 174 Content-Type [6] of application/octet-stream. Once the channel is 175 open, the listener (not the initiator) sends a MSG message indicating 176 it is ready to act as a syslog sink. (Refer to [3]'s Section 2.1 for 177 a discussion of roles that a BEEP peer may perform, including 178 definitions of the terms "listener", "initiator", "client", and 179 "server".) 181 The initiator uses ANS replies to supply one or more syslog entries 182 in the current format, as specified in [1]. When the initiator has 183 no more entries to send, it finishes with a NUL reply and closes the 184 channel. 186 An example might appear as follows: 188 L: 189 I: 190 L: RPY 0 0 . 0 131 191 L: Content-type: application/beep+xml 192 L: 193 L: 194 L: 195 L: 196 L: END 197 I: RPY 0 0 . 0 52 198 I: Content-type: application/beep+xml 199 I: 200 I: 201 I: END 202 I: MSG 0 1 . 52 136 203 I: Content-type: application/beep+xml 204 I: 205 I: 206 I: 207 I: 208 I: END 209 L: RPY 0 1 . 131 105 210 L: Content-type: application/beep+xml 211 L: 212 L: 213 L: END 214 L: MSG 1 0 . 0 50 215 L: 216 L: Central Services. This has not been a recording. 217 L: END 218 I: ANS 1 0 . 0 112 219 I: 220 I: <34>1 2003-10-11T22:14:15.003Z mymachine.example.com su - ID47 221 - BOM'su root' failed for lonvick on /dev/pts/8END 222 I: ANS 1 0 . 112 101 1 223 I: 224 I: <165>1 2003-08-24T05:14:15.000003-07:00 192.0.2.1 225 myproc 8710 - - %% It's time to make the do-nuts.END 226 I: NUL 1 0 . 222 0 227 I: END 228 L: MSG 0 3 . 236 70 229 L: Content-Type: application/beep+xml 230 L: 231 L: 232 L: END 233 I: RPY 0 3 . 188 46 234 I: Content-Type: application/beep+xml 235 I: 236 I: 237 I: END 238 I: MSG 0 4 . 234 72 239 I: Content-Type: application/beep+xml 240 I: 241 I: 242 I: END 243 L: RPY 0 4 . 306 46 244 L: Content-type: application/beep+xml 245 L: 246 L: 247 L: END 248 L: 249 I: 250 L: 251 Here we see a BEEP session established, followed by the use of the 252 TARTARE profile. The initiator is a sender, while the listener is a 253 collector. The initiator opens the channel, but the listener sends 254 the first MSG. This allows the initiator to send any number of ANS 255 replies carrying syslog event messages. The initiator sends a NUL 256 reply to indicate it is finished. Upon receiving the NUL, the 257 listener closes the TARTARE channel. The initiator has the choice of 258 closing the entire BEEP session or opening a new syslog channel for 259 more transfers. In this example, the initiator chooses to close the 260 entire BEEP session. (Please note that in the example, as an 261 artifact of the format of this memo, the two lines not beginning with 262 I: or L: have been wrapped.) 264 The overhead for one ANS frame is about thirty octets, once the 265 initial handshakes have been exchanged. If this overhead is too 266 high, then messages are likely being generated at a high rate. In 267 this case, multiple syslog messages can be aggregated into a single 268 ANS frame, each separated by a CRLF sequence from the preceding. The 269 final message still MUST NOT end with a CRLF. 271 For example, 273 L: MSG 1 0 . 0 50 274 L: 275 L: Central Services. This has not been a recording. 276 L: END 277 I: ANS 1 0 . 0 213 0 278 I: 279 I: <34>1 2003-10-11T22:14:15.003Z mymachine.example.com su - ID47 280 - BOM'su root' failed for lonvick on /dev/pts/8 281 I: <165>1 2003-08-24T05:14:15.000003-07:00 192.0.2.1 282 myproc 8710 - - %% It's time to make the do-nuts.END 283 I: NUL 1 0 . 213 0 284 I: END 286 (Again, as an artifact of the format of this memo, the two lines 287 containing syslog entries have been wrapped.) 289 3.2. TARTARE Profile Identification and Initialization 291 The TARTARE syslog profile is identified as 293 http://xml.resource.org/profiles/syslog/TARTARE 295 in the BEEP "profile" element during channel creation. 297 No data is piggybacked during channel creation. 299 3.3. TARTARE Profile Message Syntax 301 All BEEP messages in this profile have a MIME content-type of 302 application/octet-stream. The listener's first BEEP message is 303 ignored and indeed may be empty except for headers; hence, any syntax 304 is acceptable. 306 The ANS replies the initiator sends in response MUST be formatted 307 according to Section 6 of [1]. In particular, If the receiver is 308 acting as a relay, then it is expected follow the principles laid out 309 in that specification. 311 If multiple syslog messages are included in a single ANS reply, each 312 is separated from the preceding with a CRLF. There is no ending 313 delimiter, and there is no length limitation. Note that there MUST 314 NOT be a CRLF between the text of the final syslog event message and 315 the "END" marking the trailer of the BEEP frame. 317 3.4. TARTARE Profile Message Semantics 319 The listener's opening BEEP MSG message has no semantics. (It is a 320 good place to put in an identifying greeting.) The initiator's ANS 321 replies MUST specify a facility, severity, and textual message, as 322 described in [1]. 324 4. Additional Provisioning 326 In more advanced configurations, syslog senders, relays, and 327 collectors can be configured to support various delivery priorities. 328 Multiple channels running the same profile can be opened between two 329 peers, with higher priority syslog messages routed to a channel that 330 is given more bandwidth. Such provisioning is a local matter. 332 syslog [8] discusses a number of reasons why privacy and 333 authentication of syslog entry messages may be important in a 334 networked computing environment. The nature of BEEP allows for 335 convenient layering of authentication and privacy over any BEEP 336 channel. 338 4.1. Message Authenticity 340 Section 8.7 of [1] discusses the dangers of unauthenticated syslog 341 entries. To prevent inauthentic syslog event messages from being 342 accepted, configure syslog peers to require the use of a strong 343 authentication technology for the BEEP session. 345 If provisioned for message authentication, implementations SHOULD use 346 SASL mechanism DIGEST-MD5 [7] to provision this service. 348 4.2. Message Replay 350 Section 8.4 of [1] discusses the dangers of syslog message replay. 351 To prevent syslog event messages from being replayed, configure 352 syslog peers to require the use of a strong authentication technology 353 for the BEEP session. 355 If provisioned to detect message replay, implementations SHOULD use 356 SASL mechanism DIGEST-MD5 [7] to provision this service. 358 4.3. Message Integrity 360 Section 6.5 of [8] discusses the dangers of syslog event messages 361 being maliciously altered by an attacker. To prevent messages from 362 being altered, configure syslog peers to require the use of a strong 363 authentication technology for the BEEP session. 365 If provisioned to protect message integrity, implementations SHOULD 366 use SASL mechanism DIGEST-MD5 [7] to provision this service. 368 4.4. Message Observation 370 Section 6.6 of [8] discusses the dangers (and benefits) of syslog 371 messages being visible at intermediate points along the transmission 372 path between sender and collector. To prevent messages from being 373 viewed by an attacker, configure syslog peers to require the use of a 374 transport security profile for the BEEP session. (However, other 375 traffic characteristics, e.g., volume and timing of transmissions, 376 remain observable.) 378 If provisioned to secure messages against unauthorized observation, 379 implementations SHOULD use the TLS profile [3] to provision this 380 service. The cipher algorithm used SHOULD be configurable, minimally 381 supporting TLS_RSA_WITH_3DES_EDE_CBC_SHA for backward compatability 382 and TLS_RSA_WITH_AES_256_CBC_SHA for stronger protection. It is 383 expected that new algorithms will need to be added as time passes, in 384 order to prevent compromise. No new revision of this memo should be 385 expected solely for that reason. 387 4.5. Summary of Recommended Practices 389 For the indicated protections, implementations SHOULD be configured 390 to use the indicated mechanisms: 392 Desired Protection SHOULD tune using 393 ------------------ ----------------- 394 Authentication http://iana.org/beep/SASL/DIGEST-MD5 395 + Replay http://iana.org/beep/SASL/DIGEST-MD5 396 + Integrity http://iana.org/beep/SASL/DIGEST-MD5 397 + Observation http://iana.org/beep/TLS 399 BEEP peer identities used for authentication SHOULD correspond to the 400 FQDN of the initiating peer. That is, a relay running on 401 relay.example.com should use a "user ID" of "relay.example.com" 402 within the SASL authentication profiles. 404 5. Registrations 406 5.1. Registration: The TARTARE Profile 408 Profile Identification: 409 http://xml.resource.org/profiles/syslog/TARTARE 411 Messages exchanged during Channel Creation: None 413 Messages starting one-to-one exchanges: Anything 415 Messages in positive replies: None 417 Messages in negative replies: None 419 Messages in one-to-many exchanges: Anything 421 Message Syntax: See Section 3.3 423 Message Semantics: See Section 3.4 425 Contact Information: See the "Authors' Addresses" section of this 426 memo 428 6. Reply Codes 430 The following error codes are used in the protocol: 432 code meaning 433 ==== ======= 434 200 success 436 421 service not available 438 451 requested action aborted 439 (e.g., local error in processing) 441 454 temporary authentication failure 443 500 general syntax error 444 (e.g., poorly-formed XML) 446 501 syntax error in parameters 447 (e.g., non-valid XML) 449 504 parameter not implemented 451 530 authentication required 453 534 authentication mechanism insufficient 454 (e.g., too weak, sequence exhausted, etc.) 456 535 authentication failure 458 537 action not authorized for user 460 538 authentication mechanism requires encryption 462 550 requested action not taken 463 (e.g., no requested profiles are acceptable) 465 553 parameter invalid 467 554 transaction failed 468 (e.g., policy violation) 470 7. IANA Considerations 472 The IANA is requested to note in their registrations that both 473 http://iana.org/beep/SYSLOG/RAW and 474 http://iana.org/beep/SYSLOG/COOKED are deprecated. In addition, the 475 IANA is requested to register the profile listed below. 477 7.1. Registration: BEEP Profile 479 The IANA registers the profiles specified in Section 5, and selects 480 IANA-specific URI "http://iana.org/beep/SYSLOG/TARTARE". 482 7.2. Registration: The System (Well-Known) TCP port number for syslog- 483 conn 485 A single well-known port (601) is allocated to syslog-conn. In-band 486 negotiation determines which profile to use (either the one defined 487 in this memo or one of the obsolete profiles). 489 Protocol Number: TCP 491 Message Formats, Types, Opcodes, and Sequences: See Section 3.3. 493 Functions: See Section 3.4. 495 Use of Broadcast/Multicast: none 497 Proposed Name: Reliable syslog service 499 Short name: syslog-conn 501 Contact Information: See the "Authors' Addresses" section of this 502 memo 504 8. Security Considerations 506 Consult Section 8 of [1] for a discussion of security issues for the 507 syslog service. In addition, since the TARTARE profile is defined 508 using the BEEP framework, consult [3]'s Section 8 for a discussion of 509 BEEP-specific security issues. 511 BEEP is used to provide communication security but not object 512 integrity. In other words, the messages "on the wire" can be 513 protected, but a compromised sender may undetectably generate 514 incorrect messages, and relays and collectors can modify, insert, or 515 delete messages undetectably. Other techniques must be used to 516 assure that such compromises are detectable. 518 9. Acknowledgements 520 The authors gratefully acknowledge the contributions of Christopher 521 Calabrese, Keith McCloghrie, Balazs Scheidler, and David Waitzman. 523 10. References 525 10.1. Normative References 527 [1] Gerhards, R., "The syslog Protocol", 528 draft-ietf-syslog-protocol-22 (work in progress), August 2007. 530 [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement 531 Levels", BCP 14, RFC 2119, March 1997. 533 [3] Rose, M., "The Blocks Extensible Exchange Protocol Core", 534 RFC 3080, March 2001. 536 [4] Rose, M., "Mapping the BEEP Core onto TCP", RFC 3081, 537 March 2001. 539 [5] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 540 specifying the location of services (DNS SRV)", RFC 2782, 541 February 2000. 543 [6] Freed, N. and N. Borenstein, "Multipurpose Internet Mail 544 Extensions (MIME) Part Two: Media Types", RFC 2046, 545 November 1996. 547 [7] Leach, P. and C. Newman, "Using Digest Authentication as a SASL 548 Mechanism", RFC 2831, May 2000. 550 10.2. Informative References 552 [8] Lonvick, C., "The BSD Syslog Protocol", RFC 3164, August 2001. 554 [9] New, D. and M. Rose, "Reliable Delivery for syslog", RFC 3195, 555 November 2001. 557 Appendix A. Coexistence with old RAW and COOKED modes 559 This memo specifies a new profile for syslog messages that adhere to 560 the specification in [1]. It is recommended that messages using the 561 older format specified in [8] continue to make use of the deprecated 562 RAW or COOKED profiles specified in [9]. This allows for easy 563 separation of old and new syslog formats. 565 Appendix B. Changes from RFC 3195 567 o Deprecated RAW and COOKED profiles. 569 o Shamelessly copied the RAW profile to a new name and updated it so 570 that there is no length limitation. 572 o Split references into normative and informative 574 o In the new model, authors have chosen "sender" instead of 575 "device". We have adopted that language in this draft. 577 o Updated the language for TLS encryption algorithms to reflect 578 current thinking. 580 o Use examples from [1] 582 Appendix C. To Do 584 o Review connection termination. 586 o Check byte counts. 588 Authors' Addresses 590 Darren New 591 5390 Caminito Exquisito 592 San Diego, CA 92130 593 US 595 Phone: +1 858 350 9733 596 Email: dnew@san.rr.com 598 Marshall T. Rose 599 Dover Beach Consulting, Inc. 600 POB 255268 601 Sacramento, CA 95865-5268 602 US 604 Phone: +1 916 483 8878 605 Email: mrose@dbc.mtview.ca.us 607 Eliot Lear 608 Cisco Systems 609 Glatt-com 610 Glattzentrum, Zurich 8301 611 CH 613 Email: lear@cisco.com 615 Full Copyright Statement 617 Copyright (C) The IETF Trust (2007). 619 This document is subject to the rights, licenses and restrictions 620 contained in BCP 78, and except as set forth therein, the authors 621 retain all their rights. 623 This document and the information contained herein are provided on an 624 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 625 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 626 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 627 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 628 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 629 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 631 Intellectual Property 633 The IETF takes no position regarding the validity or scope of any 634 Intellectual Property Rights or other rights that might be claimed to 635 pertain to the implementation or use of the technology described in 636 this document or the extent to which any license under such rights 637 might or might not be available; nor does it represent that it has 638 made any independent effort to identify any such rights. 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