Network Working Group D. New Internet-Draft Obsoletes: 3195 (if approved) M. Rose Intended status: Standards Track Dover Beach Consulting, Inc. Expires: May 11, 2008 E. Lear Cisco Systems November 8, 2007 Reliable Delivery for syslog draft-ietf-syslog-rfc3195bis-00 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on May 11, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). New, et al. Expires May 11, 2008 [Page 1]
Internet-Draft Reliable Delivery for syslog November 2007 Abstract The syslog protocol describes a number of service options related to propagating event messages. This memo describes a mapping of the syslog protocol to TCP connections, useful for reliable delivery of event messages through the use of a BEEP profile. The earlier RAW and COOKED BEEP syslog profiles are deprecated. The use of syslog over BEEP provides robustness and security in message delivery that is unavailable to the usual UDP-based syslog protocol, by providing encryption and authentication over a connection-oriented protocol. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Model . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. The TARTARE Profile . . . . . . . . . . . . . . . . . . . . . 5 3.1. TARTARE Profile Overview . . . . . . . . . . . . . . . . . 5 3.2. TARTARE Profile Identification and Initialization . . . . 7 3.3. TARTARE Profile Message Syntax . . . . . . . . . . . . . . 8 3.4. TARTARE Profile Message Semantics . . . . . . . . . . . . 8 4. Additional Provisioning . . . . . . . . . . . . . . . . . . . 9 4.1. Message Authenticity . . . . . . . . . . . . . . . . . . . 9 4.2. Message Replay . . . . . . . . . . . . . . . . . . . . . . 9 4.3. Message Integrity . . . . . . . . . . . . . . . . . . . . 9 4.4. Message Observation . . . . . . . . . . . . . . . . . . . 9 4.5. Summary of Recommended Practices . . . . . . . . . . . . . 10 5. Registrations . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1. Registration: The TARTARE Profile . . . . . . . . . . . . 11 6. Reply Codes . . . . . . . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 7.1. Registration: BEEP Profile . . . . . . . . . . . . . . . . 13 7.2. Registration: The System (Well-Known) TCP port number for syslog-conn . . . . . . . . . . . . . . . . . . . . . 13 8. Security Considerations . . . . . . . . . . . . . . . . . . . 14 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 15 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 16 10.1. Normative References . . . . . . . . . . . . . . . . . . . 16 10.2. Informative References . . . . . . . . . . . . . . . . . . 16 Appendix A. Coexistence with old RAW and COOKED modes . . . . . . 17 Appendix B. Changes from RFC 3195 . . . . . . . . . . . . . . . . 18 Appendix C. To Do . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20 Intellectual Property and Copyright Statements . . . . . . . . . . 21 New, et al. Expires May 11, 2008 [Page 2]
Internet-Draft Reliable Delivery for syslog November 2007 1. Introduction The syslog protocol [1] presents a spectrum of service options for provisioning an event-based logging service over a network. Each option has associated benefits and costs. Accordingly, the choice as to what combination of options is provisioned is both an engineering and administrative decision. This memo describes how to realize the syslog protocol when reliable delivery is selected as a required service. It is beyond the scope of this memo to argue for, or against, the use of reliable delivery for the syslog protocol. This memo is a revision of previous work [9]. Based on implementation and deployment experience, and the expectation of new work in the field, the principle changes to this document are these: o Both the COOKED and the RAW profiles are deprecated. The COOKED profile is deprecated because there has been no substantial deployment and it is no longer consistent with the work done in [1]. o The RAW profile is reproduced as a new profile, TARTARE, that has no length limitations. Removal of the 1024 octet limitation is necessary for future worked in the area of "signed syslog". Previous length limitations continue to apply to the deprecated RAW and COOKED profiles. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [2]. New, et al. Expires May 11, 2008 [Page 3]
Internet-Draft Reliable Delivery for syslog November 2007 2. The Model The reader is referred to [1] for the authoritative explanation of the syslog model. What follows are issues relating to that model that are specific to BEEP and this mapping. It should be noted that a role of sender, relay, or collector is relevant only to a particular BEEP channel (q.v., below). A single server can serve as a sender, a relay, and a collector, all at once, if so configured. It can even serve as a relay and a collector to the same sender or device at the same time using different BEEP channels over the same connection-oriented session; this might be useful to collect status yet relay urgent error messages. To provide reliable delivery when realizing the syslog protocol, this memo defines a new BEEP profile. BEEP [3] is a generic application protocol framework for connection-oriented, asynchronous interactions. Within BEEP, features such as authentication, privacy, and reliability through retransmission are provided. The new TARTARE profile is designed to provide a high-performance, low-impact footprint, using essentially the same format as the existing UDP- based syslog service. BEEP defines "transport mappings," specifying how BEEP messages are carried over the underlying transport technologies. At the time of this writing, only one such transport is defined, in [4], which specifies BEEP over TCP. All transport mappings are required to support enough reliability and sequencing to allow all BEEP messages on a given channel to be delivered reliably and in order. Hence, the TARTARE profile provides reliable delivery of messages. Senders and relays MAY discover relays and collectors via the DNS SRV algorithm [5]. If so configured, the service used is "syslog" and the protocol used is "tcp". This allows for central administration of addressing, fallback for failed relays and collectors, and static load balancing. Security policies and hardware configurations may be such that device configuration is more secure than the DNS server. Hardware devices may be of such limited resources that DNS SRV access is inappropriate. Firewalls and other restrictive routing mechanisms may need to be dealt with before a reliable syslog connection can be established. In these cases, DNS might not be the most appropriate configuration mechanism. New, et al. Expires May 11, 2008 [Page 4]
Internet-Draft Reliable Delivery for syslog November 2007 3. The TARTARE Profile 3.1. TARTARE Profile Overview The TARTARE profile is designed for minimal implementation effort, high efficiency, and backwards compatibility. It should be noted that even though the TARTARE profile uses the same format for message payloads as the UDP version of syslog uses, delivery is reliable. The TARTARE syslog profile is a profile of BEEP [3], and BEEP guarantees ordered reliable delivery of messages within each individual channel. When the profile is started, no piggyback data is supplied. All BEEP messages in the TARTARE profile are specified as having a MIME Content-Type [6] of application/octet-stream. Once the channel is open, the listener (not the initiator) sends a MSG message indicating it is ready to act as a syslog sink. (Refer to [3]'s Section 2.1 for a discussion of roles that a BEEP peer may perform, including definitions of the terms "listener", "initiator", "client", and "server".) The initiator uses ANS replies to supply one or more syslog entries in the current format, as specified in [1]. When the initiator has no more entries to send, it finishes with a NUL reply and closes the channel. An example might appear as follows: L: <wait for incoming connection> I: <establish connection> L: RPY 0 0 . 0 131 L: Content-type: application/beep+xml L: L: <greeting> L: <profile uri='http://xml.resource.org/profiles/syslog/TARTARE' /> L: </greeting> L: END I: RPY 0 0 . 0 52 I: Content-type: application/beep+xml I: I: <greeting /> I: END I: MSG 0 1 . 52 136 I: Content-type: application/beep+xml I: I: <start number='1'> I: <profile uri='http://xml.resource.org/profiles/syslog/TARTARE' /> New, et al. Expires May 11, 2008 [Page 5]
Internet-Draft Reliable Delivery for syslog November 2007 I: </start> I: END L: RPY 0 1 . 131 105 L: Content-type: application/beep+xml L: L: <profile uri='http://xml.resource.org/profiles/syslog/TARTARE' /> L: END L: MSG 1 0 . 0 50 L: L: Central Services. This has not been a recording. L: END I: ANS 1 0 . 0 112 I: I: <34>1 2003-10-11T22:14:15.003Z mymachine.example.com su - ID47 - BOM'su root' failed for lonvick on /dev/pts/8END I: ANS 1 0 . 112 101 1 I: I: <165>1 2003-08-24T05:14:15.000003-07:00 192.0.2.1 myproc 8710 - - %% It's time to make the do-nuts.END I: NUL 1 0 . 222 0 I: END L: MSG 0 3 . 236 70 L: Content-Type: application/beep+xml L: L: <close number='1' code='200' /> L: END I: RPY 0 3 . 188 46 I: Content-Type: application/beep+xml I: I: <ok /> I: END I: MSG 0 4 . 234 72 I: Content-Type: application/beep+xml I: I: <close number='0' code='200' /> I: END L: RPY 0 4 . 306 46 L: Content-type: application/beep+xml L: L: <ok /> L: END L: <closes connection> I: <closes connection> L: <awaits next connection> New, et al. Expires May 11, 2008 [Page 6]
Internet-Draft Reliable Delivery for syslog November 2007 Here we see a BEEP session established, followed by the use of the TARTARE profile. The initiator is a sender, while the listener is a collector. The initiator opens the channel, but the listener sends the first MSG. This allows the initiator to send any number of ANS replies carrying syslog event messages. The initiator sends a NUL reply to indicate it is finished. Upon receiving the NUL, the listener closes the TARTARE channel. The initiator has the choice of closing the entire BEEP session or opening a new syslog channel for more transfers. In this example, the initiator chooses to close the entire BEEP session. (Please note that in the example, as an artifact of the format of this memo, the two lines not beginning with I: or L: have been wrapped.) The overhead for one ANS frame is about thirty octets, once the initial handshakes have been exchanged. If this overhead is too high, then messages are likely being generated at a high rate. In this case, multiple syslog messages can be aggregated into a single ANS frame, each separated by a CRLF sequence from the preceding. The final message still MUST NOT end with a CRLF. For example, L: MSG 1 0 . 0 50 L: L: Central Services. This has not been a recording. L: END I: ANS 1 0 . 0 213 0 I: I: <34>1 2003-10-11T22:14:15.003Z mymachine.example.com su - ID47 - BOM'su root' failed for lonvick on /dev/pts/8 I: <165>1 2003-08-24T05:14:15.000003-07:00 192.0.2.1 myproc 8710 - - %% It's time to make the do-nuts.END I: NUL 1 0 . 213 0 I: END (Again, as an artifact of the format of this memo, the two lines containing syslog entries have been wrapped.) 3.2. TARTARE Profile Identification and Initialization The TARTARE syslog profile is identified as http://xml.resource.org/profiles/syslog/TARTARE in the BEEP "profile" element during channel creation. No data is piggybacked during channel creation. New, et al. Expires May 11, 2008 [Page 7]
Internet-Draft Reliable Delivery for syslog November 2007 3.3. TARTARE Profile Message Syntax All BEEP messages in this profile have a MIME content-type of application/octet-stream. The listener's first BEEP message is ignored and indeed may be empty except for headers; hence, any syntax is acceptable. The ANS replies the initiator sends in response MUST be formatted according to Section 6 of [1]. In particular, If the receiver is acting as a relay, then it is expected follow the principles laid out in that specification. If multiple syslog messages are included in a single ANS reply, each is separated from the preceding with a CRLF. There is no ending delimiter, and there is no length limitation. Note that there MUST NOT be a CRLF between the text of the final syslog event message and the "END" marking the trailer of the BEEP frame. 3.4. TARTARE Profile Message Semantics The listener's opening BEEP MSG message has no semantics. (It is a good place to put in an identifying greeting.) The initiator's ANS replies MUST specify a facility, severity, and textual message, as described in [1]. New, et al. Expires May 11, 2008 [Page 8]
Internet-Draft Reliable Delivery for syslog November 2007 4. Additional Provisioning In more advanced configurations, syslog senders, relays, and collectors can be configured to support various delivery priorities. Multiple channels running the same profile can be opened between two peers, with higher priority syslog messages routed to a channel that is given more bandwidth. Such provisioning is a local matter. syslog [8] discusses a number of reasons why privacy and authentication of syslog entry messages may be important in a networked computing environment. The nature of BEEP allows for convenient layering of authentication and privacy over any BEEP channel. 4.1. Message Authenticity Section 8.7 of [1] discusses the dangers of unauthenticated syslog entries. To prevent inauthentic syslog event messages from being accepted, configure syslog peers to require the use of a strong authentication technology for the BEEP session. If provisioned for message authentication, implementations SHOULD use SASL mechanism DIGEST-MD5 [7] to provision this service. 4.2. Message Replay Section 8.4 of [1] discusses the dangers of syslog message replay. To prevent syslog event messages from being replayed, configure syslog peers to require the use of a strong authentication technology for the BEEP session. If provisioned to detect message replay, implementations SHOULD use SASL mechanism DIGEST-MD5 [7] to provision this service. 4.3. Message Integrity Section 6.5 of [8] discusses the dangers of syslog event messages being maliciously altered by an attacker. To prevent messages from being altered, configure syslog peers to require the use of a strong authentication technology for the BEEP session. If provisioned to protect message integrity, implementations SHOULD use SASL mechanism DIGEST-MD5 [7] to provision this service. 4.4. Message Observation Section 6.6 of [8] discusses the dangers (and benefits) of syslog messages being visible at intermediate points along the transmission New, et al. Expires May 11, 2008 [Page 9]
Internet-Draft Reliable Delivery for syslog November 2007 path between sender and collector. To prevent messages from being viewed by an attacker, configure syslog peers to require the use of a transport security profile for the BEEP session. (However, other traffic characteristics, e.g., volume and timing of transmissions, remain observable.) If provisioned to secure messages against unauthorized observation, implementations SHOULD use the TLS profile [3] to provision this service. The cipher algorithm used SHOULD be configurable, minimally supporting TLS_RSA_WITH_3DES_EDE_CBC_SHA for backward compatability and TLS_RSA_WITH_AES_256_CBC_SHA for stronger protection. It is expected that new algorithms will need to be added as time passes, in order to prevent compromise. No new revision of this memo should be expected solely for that reason. 4.5. Summary of Recommended Practices For the indicated protections, implementations SHOULD be configured to use the indicated mechanisms: Desired Protection SHOULD tune using ------------------ ----------------- Authentication http://iana.org/beep/SASL/DIGEST-MD5 + Replay http://iana.org/beep/SASL/DIGEST-MD5 + Integrity http://iana.org/beep/SASL/DIGEST-MD5 + Observation http://iana.org/beep/TLS BEEP peer identities used for authentication SHOULD correspond to the FQDN of the initiating peer. That is, a relay running on relay.example.com should use a "user ID" of "relay.example.com" within the SASL authentication profiles. New, et al. Expires May 11, 2008 [Page 10]
Internet-Draft Reliable Delivery for syslog November 2007 5. Registrations 5.1. Registration: The TARTARE Profile Profile Identification: http://xml.resource.org/profiles/syslog/TARTARE Messages exchanged during Channel Creation: None Messages starting one-to-one exchanges: Anything Messages in positive replies: None Messages in negative replies: None Messages in one-to-many exchanges: Anything Message Syntax: See Section 3.3 Message Semantics: See Section 3.4 Contact Information: See the "Authors' Addresses" section of this memo New, et al. Expires May 11, 2008 [Page 11]
Internet-Draft Reliable Delivery for syslog November 2007 6. Reply Codes The following error codes are used in the protocol: code meaning ==== ======= 200 success 421 service not available 451 requested action aborted (e.g., local error in processing) 454 temporary authentication failure 500 general syntax error (e.g., poorly-formed XML) 501 syntax error in parameters (e.g., non-valid XML) 504 parameter not implemented 530 authentication required 534 authentication mechanism insufficient (e.g., too weak, sequence exhausted, etc.) 535 authentication failure 537 action not authorized for user 538 authentication mechanism requires encryption 550 requested action not taken (e.g., no requested profiles are acceptable) 553 parameter invalid 554 transaction failed (e.g., policy violation) New, et al. Expires May 11, 2008 [Page 12]
Internet-Draft Reliable Delivery for syslog November 2007 7. IANA Considerations The IANA is requested to note in their registrations that both http://iana.org/beep/SYSLOG/RAW and http://iana.org/beep/SYSLOG/COOKED are deprecated. In addition, the IANA is requested to register the profile listed below. 7.1. Registration: BEEP Profile The IANA registers the profiles specified in Section 5, and selects IANA-specific URI "http://iana.org/beep/SYSLOG/TARTARE". 7.2. Registration: The System (Well-Known) TCP port number for syslog- conn A single well-known port (601) is allocated to syslog-conn. In-band negotiation determines which profile to use (either the one defined in this memo or one of the obsolete profiles). Protocol Number: TCP Message Formats, Types, Opcodes, and Sequences: See Section 3.3. Functions: See Section 3.4. Use of Broadcast/Multicast: none Proposed Name: Reliable syslog service Short name: syslog-conn Contact Information: See the "Authors' Addresses" section of this memo New, et al. Expires May 11, 2008 [Page 13]
Internet-Draft Reliable Delivery for syslog November 2007 8. Security Considerations Consult Section 8 of [1] for a discussion of security issues for the syslog service. In addition, since the TARTARE profile is defined using the BEEP framework, consult [3]'s Section 8 for a discussion of BEEP-specific security issues. BEEP is used to provide communication security but not object integrity. In other words, the messages "on the wire" can be protected, but a compromised sender may undetectably generate incorrect messages, and relays and collectors can modify, insert, or delete messages undetectably. Other techniques must be used to assure that such compromises are detectable. New, et al. Expires May 11, 2008 [Page 14]
Internet-Draft Reliable Delivery for syslog November 2007 9. Acknowledgements The authors gratefully acknowledge the contributions of Christopher Calabrese, Keith McCloghrie, Balazs Scheidler, and David Waitzman. New, et al. Expires May 11, 2008 [Page 15]
Internet-Draft Reliable Delivery for syslog November 2007 10. References 10.1. Normative References [1] Gerhards, R., "The syslog Protocol", draft-ietf-syslog-protocol-22 (work in progress), August 2007. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [3] Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC 3080, March 2001. [4] Rose, M., "Mapping the BEEP Core onto TCP", RFC 3081, March 2001. [5] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for specifying the location of services (DNS SRV)", RFC 2782, February 2000. [6] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996. [7] Leach, P. and C. Newman, "Using Digest Authentication as a SASL Mechanism", RFC 2831, May 2000. 10.2. Informative References [8] Lonvick, C., "The BSD Syslog Protocol", RFC 3164, August 2001. [9] New, D. and M. Rose, "Reliable Delivery for syslog", RFC 3195, November 2001. New, et al. Expires May 11, 2008 [Page 16]
Internet-Draft Reliable Delivery for syslog November 2007 Appendix A. Coexistence with old RAW and COOKED modes This memo specifies a new profile for syslog messages that adhere to the specification in [1]. It is recommended that messages using the older format specified in [8] continue to make use of the deprecated RAW or COOKED profiles specified in [9]. This allows for easy separation of old and new syslog formats. New, et al. Expires May 11, 2008 [Page 17]
Internet-Draft Reliable Delivery for syslog November 2007 Appendix B. Changes from RFC 3195 o Deprecated RAW and COOKED profiles. o Shamelessly copied the RAW profile to a new name and updated it so that there is no length limitation. o Split references into normative and informative o In the new model, authors have chosen "sender" instead of "device". We have adopted that language in this draft. o Updated the language for TLS encryption algorithms to reflect current thinking. o Use examples from [1] New, et al. Expires May 11, 2008 [Page 18]
Internet-Draft Reliable Delivery for syslog November 2007 Appendix C. To Do o Review connection termination. o Check byte counts. New, et al. Expires May 11, 2008 [Page 19]
Internet-Draft Reliable Delivery for syslog November 2007 Authors' Addresses Darren New 5390 Caminito Exquisito San Diego, CA 92130 US Phone: +1 858 350 9733 Email: dnew@san.rr.com Marshall T. Rose Dover Beach Consulting, Inc. POB 255268 Sacramento, CA 95865-5268 US Phone: +1 916 483 8878 Email: mrose@dbc.mtview.ca.us Eliot Lear Cisco Systems Glatt-com Glattzentrum, Zurich 8301 CH Email: lear@cisco.com New, et al. Expires May 11, 2008 [Page 20]
Internet-Draft Reliable Delivery for syslog November 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Intellectual Property The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). New, et al. Expires May 11, 2008 [Page 21]
