Received: from relay.tis.com by neptune.TIS.COM id aa27953; 3 Oct 95 17:02 EDT Received: from unknown.tycho.ncsc.mil(144.51.3.1) by relay.tis.com via smap (g3.0.1) id xma006398; Tue, 3 Oct 95 16:45:17 -0400 Received: by tarius.tycho.ncsc.mil (4.1/SMI-4.1) id AA08390; Tue, 3 Oct 95 17:02:56 EDT Date: Tue, 3 Oct 95 17:02:56 EDT From: "Scott J. Carlson" Message-Id: <9510032102.AA08390@tarius.tycho.ncsc.mil> To: dns-security@TIS.COM Subject: freebsd compilation Hey there, I am currently working with Your DNS Security Implementation Package sec_bind493-b26-v1.2.tar.gz I was curious if you have had anyone successfully compile this package under freebsd v2.0.5 Rel #7? If so, could you please point me in their direction or send me the diffs for the things they had to change in order to get it to compile. I am having problems myself, and am just about to get ready to edit some of the makefiles and stuff, but if someone else has done it first, I may as well as use their work. Thanks a lot Scott Carlson National Security Agency sjc@tycho.ncsc.mil   Received: from relay.tis.com by neptune.TIS.COM id aa01883; 3 Oct 95 21:52 EDT Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma009037; Tue, 3 Oct 95 21:35:43 -0400 Received: by callandor.cybercash.com; id VAA18817; Tue, 3 Oct 1995 21:52:10 -0400 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.1) id xma018814; Tue, 3 Oct 95 21:51:47 -0400 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA10656; Tue, 3 Oct 95 21:51:54 EDT Date: Tue, 3 Oct 1995 21:51:52 -0400 (EDT) From: "Donald E. Eastlake 3rd" To: dns-security@TIS.COM Cc: jis@mit.edu, yakov@cisco.com, Susan Thomson in WG hat , Randy Bush Subject: "Null" SIGs, NXT ordering, SIG orig TTL Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII I have made some minor edits and one significant change to the last posted version of the DNS Security draft. I do not plan to send this latest version in to Internet-Drafts until waiting a bit for comments. The significant change is to define Algorithm 253 as the null security algorithm. That is to say, KEY algorithm type 253 has null key information and SIG algorithm type 253 has a null signature part. The primary reason for this SIG type is so that DNS dynamic updates can be done without any security overhead in the same way as secure dynamic updates can be done. (Presumably one would only do this inside a secure subnet where all hosts were trusted...) The DNS dynamic update uses the date signed field in the SIG and that, along with all of the other RDATA fields, except signature, is still present in algorithm type 253 SIGs. An algorithm type 253 KEY is necessary so that you can authoritatively declare that algorithm type 253 SIGs can be used in a zone. Secure DNS resover and similar software should normally treate a zone authoritatively secured by algorithm type 253 as if it were a zone authoritatively declared to be insecure. Such software needs, in any case, to know which algoirthms or possibly even key lengths it will consider secure and which it will consider insecure. The minor changes consist of fixing some typos (pubic -> public, etc.), changing referenced to dynamic update to the present tense, etc., and also (1) providing that the ordering of labels for NXT purposes is as if all letters were lower case (to follow the hash ordering rules) and (2) providing that the original TTL field for a SIG can be omitted in a master file if it is the same at the TTL of the SIG itself. I will append the new version (draft-ietf-dnssec-secext-06.txt) below. People are welcome to do diffs with the previous version, comment, or whatever. Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA) DNS Security Working Group Donald E. Eastlake, 3rd INTERNET-DRAFT CyberCash UPDATES RFC 1034, 1035 Charles W. Kaufman Iris Expires: 2 April 1996 3 October 1995 Domain Name System Security Extensions ------ ---- ------ -------- ---------- Status of This Document This draft, file name draft-ietf-dnssec-secext-06.txt, is intended to be become a Proposed Standard RFC. Distribution of this document is unlimited. Comments should be sent to the DNS Security Working Group mailing list or to the authors. This document is an Internet-Draft. 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. Internet-Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet- Drafts as reference material or to cite them other than as a ``working draft'' or ``work in progress.'' To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net, ftp.isi.edu, nic.nordu.net, ftp.nis.garr.it, munnari.oz.au, or ftp.is.co.za. Eastlake, Kaufman [Page 1] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Abstract The Domain Name System (DNS) has become a critical operational part of the Internet infrastructure yet it has no strong security mechanisms to assure data integrity or authentication. Extensions to the DNS are described that provide these services to security aware resolvers or applications through the use of cryptographic digital signatures. These digital signatures are included in secured zones as resource records. Security can still be provided even through non-security aware DNS servers in many cases. The extensions also provide for the storage of authenticated public keys in the DNS. This storage of keys can support general public key distribution service as well as DNS security. The stored keys enable security aware resolvers to learn the authenticating key of zones in addition to keys for which they are initially configured. Keys associated with DNS names can be retrieved to support other protocols. Provision is made for a variety of key types and algorithms. In addition, the security extensions provide for the optional authentication of DNS protocol transactions. Acknowledgements The significant contributions of the following persons (in alphabetic order) to this draft are gratefully acknowledged: Madelyn Badger Matt Crawford James M. Galvin Olafur Gudmundsson Sandy Murphy Masataka Ohta Michael A. Patton Jeffrey I. Schiller Eastlake, Kaufman [Page 2] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Table of Contents Status of This Document....................................1 Abstract...................................................2 Acknowledgements...........................................2 Table of Contents..........................................3 1. Overview of Contents....................................5 2. Overview of the Extensions.............................6 2.1 Services Not Provided..................................6 2.2 Key Distribution.......................................6 2.3 Data Origin Authentication and Integrity...............7 2.3.1 The SIG Resource Record..............................8 2.3.2 Authenticating Name and Type Non-existence...........8 2.3.3 Special Considerations With Time-to-Live.............8 2.3.4 Special Considerations at Delegation Points..........9 2.3.5 Special Considerations with CNAME RRs................9 2.3.6 Signers Other Than The Zone.........................10 2.4 DNS Transaction Authentication........................10 3. The KEY Resource Record................................11 3.1 KEY RDATA format......................................11 3.2 Object Types, DNS Names, and Keys.....................11 3.3 The KEY RR Flag Field.................................12 3.4 The Protocol Octet....................................14 3.5 The KEY Algorithm Number and the MD5/RSA Algorithm....14 3.6 Interaction of Flags, Algorithm, and Protocol Bytes...15 3.7 KEY RRs in the Construction of Responses..............16 3.8 File Representation of KEY RRs........................16 4. The SIG Resource Record................................18 4.1 SIG RDATA Format......................................18 4.1.1 Signature Data......................................20 4.1.2 MD5/RSA Algorithm Signature Calculation.............21 4.1.3 Zone Transfer (AXFR) SIG............................22 4.1.4 Transaction SIGs....................................22 4.2 SIG RRs in the Construction of Responses..............23 4.3 Processing Responses and SIG RRs......................24 4.4 Signature Expiration, TTLs, and Validity..............25 4.5 File Representation of SIG RRs........................25 5. Non-existent Names and Types...........................27 5.1 The NXT Resource Record...............................27 5.2 NXT RDATA Format......................................28 5.3 Example...............................................28 5.4 Interaction of NXT RRs and Wildcard RRs...............29 5.5 Blocking NXT Pseudo-Zone Transfers....................30 Eastlake, Kaufman [Page 3] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 5.6 Special Considerations at Delegation Points...........30 6. The AD and CD Bits and How to Resolve Securely.........31 6.1 The AD and CD Header Bits.............................31 6.2 Boot File Format......................................32 6.3 Chaining Through Zones................................33 6.4 Secure Time...........................................34 7. Operational Considerations.............................35 7.1 Key Size Considerations...............................35 7.2 Key Storage...........................................36 7.3 Key Generation........................................36 7.4 Key Lifetimes.........................................36 7.5 Signature Lifetime....................................37 7.6 Root..................................................37 8. Conformance............................................38 8.1 Server Conformance....................................38 8.2 Resolver Conformance..................................38 9. Security Considerations................................39 References................................................39 Authors Addresses.........................................41 Expiration and File Name..................................41 Appendix: Base 64 Encoding................................42 Eastlake, Kaufman [Page 4] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 1. Overview of Contents This draft describes extensions of the Domain Name System (DNS) protocol to support DNS security and public key distribution. It assumes that the reader is familiar with the Domain Name System, particularly as described in RFCs 1034 and 1035. Section 2 provides an overview of the extensions and the key distribution, data origin authentication, and transaction security they provide. Section 3 discusses the KEY resource record, its structure, use in DNS responses, and file representation. These resource records represent the public keys of entities named in the DNS and are used for key distribution. Section 4 discusses the SIG digital signature resource record, its structure, use in DNS responses, and file representation. These resource records are used to authenticate other resource records in the DNS and optionally to authenticate DNS transactions. Section 5 discusses the NXT resource record and its use in DNS responses. The NXT RR permits authenticated denial in the DNS of the existence of a name or of a particular type for an existing name. Section 6 discusses how a resolver can be configured with a starting key or keys and proceed to securely resolve DNS requests. Interactions between resolvers and servers are discussed for all combinations of security aware and security non-aware. Two additional query header bits are defined for signaling between resolvers and servers. Section 7 reviews a variety of operational considerations including key generation, lifetime, and storage. Section 8 defines levels of conformance for resolvers and servers. Section 9 provides a few paragraphs on overall security considerations. An Appendix is provided that gives some details of base64 encoding which is used in the file representation of some RR's defined in this draft. Eastlake, Kaufman [Page 5] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 2. Overview of the Extensions The Domain Name System (DNS) protocol security extensions provide three distinct services: key distribution as described in Section 2.2 below, data origin authentication as described in Section 2.3 below, and transaction authentication, described in Section 2.4 below. Special considerations related to time to live, CNAMEs, and delegation points are also discussed in Section 2.3. 2.1 Services Not Provided It is part of the design philosophy of the DNS that the data in it is public and that the DNS gives the same answers to all inquirers. Following this philosophy, no attempt has been made to include any sort of access control lists or other means to differentiate inquirers. In addition, no effort has been made to provide for any confidentiality for queries or responses. (This service may be available via IPSEC. [put refs to IPSEC RFCs here if available]) 2.2 Key Distribution Resource records (RRs) are defined to associate keys with DNS names. This permits the DNS to be used as a general public key distribution mechanism in support of the data origin authentication and transaction authentication DNS services as well as other security services. The syntax of a KEY resource record (RR) is described in Section 3. It includes an algorithm identifier, flags indicating the type of entity the key is associated with and/or asserting that there is no key associated with that entity, and the actual public key parameters. Under conditions described in Section 3, security aware DNS servers may automatically attempt to return KEY resources as additional information, along with those resource records actually requested, to minimize the number of queries needed. Eastlake, Kaufman [Page 6] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 2.3 Data Origin Authentication and Integrity Authentication is provided by associating with resource records in the DNS cryptographically generated digital signatures. Commonly, there will be a single private key that signs for an entire zone. If a security aware resolver reliably learns the public key of the zone, it can verify, for any data read from that zone, that it was properly authorized and is reasonably current. The expected implementation is for the zone private key to be kept off-line and used to re-sign all of the records in the zone periodically. This data origin authentication key belongs to the zone and not to the servers that store copies of the data. That means compromise of a server or even all servers for a zone will not necessarily affect the degree of assurance that a resolver has that it can determine whether data is genuine. A resolver can learn the public key of a zone either by reading it from DNS or by having it staticly configured. To reliably learn the public key by reading it from DNS, the key itself must be signed. Thus, to provide a reasonable degree of security, the resolver must be configured with at least the public key of one zone that it can use to authenticate signatures. From that, it can securely read the public keys of other zones if the intervening zones in the DNS tree are secure. (It is in principle more secure to have the resolver manually configured with the public keys of multiple zones, since then the compromise of a single zone would not permit the faking of information from other zones. It is also more administratively cumbersome, however, particularly when public keys change.) Adding data origin authentication and integrity requires no change to the "on-the-wire" DNS protocol beyond the addition of the signature resource types and, as a practical matter, the key resource type needed for key distribution. This service can be supported by existing resolver and server implementations so long as they can support the additional resource types (see Section 8) with the one exception that CNAME referals can not be authenticated if they are from non-security aware servers (see Section 2.3.5). If signatures are always separately retrieved and verified when retrieving the information they authenticate, there will be more trips to the server and performance will suffer. To avoid this, security aware servers mitigate that degradation by always sending the signature(s) needed. Eastlake, Kaufman [Page 7] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 2.3.1 The SIG Resource Record The syntax of a SIG resource record (signature) is described in Section 4. It includes the type of the RR(s) being signed, the name of the signer, the time at which the signature was created, the time it expires (when it is no longer to be believed), its original time to live (which may be longer than its current time to live but cannot be shorter), the cryptographic algorithm in use, and the actual signature. Every name in a secured zone will have associated with it at least one SIG resource record for each resource type under that name. A security aware server supporting the performance enhanced version of the DNS protocol security extensions will attempt to return, with all records retrieved, the corresponding SIGs. If a server does not support the protocol, the resolver must retrieve all the SIG records for a name and select the one or ones that sign the resource record(s) that resolver is interested in. 2.3.2 Authenticating Name and Type Non-existence The above security mechanism provides only a way to sign existing RRs in a zone. "Data origin" authentication is not obviously provided for the non-existence of a domain name in a zone or the non-existence of a type for an existing name. This gap is filled by the NXT RR which authenticatably asserts a range of non-existent names in a zone and the non-existence types for the initial name in that range. Section 5 below covers the NXT RR. 2.3.3 Special Considerations With Time-to-Live A digital signature will fail to verify if any change has occurred to the data between the time it was originally signed and the time the signature is verified. This conflicts with our desire to have the time-to-live field tick down when resource records are cached. This could be avoided by leaving the time-to-live out of the digital signature, but that would allow unscrupulous servers to set arbitrarily long time to live values undetected. Instead, we include the "original" time-to-live in the signature and communicate that data in addition to the current time-to-live. Unscrupulous servers under this scheme can manipulate the time to live but a security aware resolver will bound the TTL value it uses at the original signed value. Separately, signatures include a time signed and an expiration time. A resolver that knows the absolute time can Eastlake, Kaufman [Page 8] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 determine securely whether a signature has expired. It is not possible to rely solely on the signature expiration as a substitute for the TTL, however, since non-security aware servers must still be supported. 2.3.4 Special Considerations at Delegation Points DNS security would like to view each zone as a unit of data completely under the control of the zone owner and signed by the zone's key. But the operational DNS views the leaf nodes in a zone which are also the apex nodes of a subzone (i.e., delegation points) as "really" belonging to the subzone. These nodes occur in two master files and will have RRs signed by both the upper and lower zone's keys. A retrieval could get a mixture of these RRs and SIGs, especially since one server could be serving both the zone above and below a delegation point. In general, the KEY RR from the superzone is authoritative while for all other RRs, the data from the subzone is more authoritative. To avoid conflicts, only the KEY RR in the superzone should be signed and the NS and any A (glue) RRs should only be signed in the subzone along with the SOA and any other RRs that have the zone name as owner. The only exception is the NXT RR type that will always appear differently and authoritatively in both the superzone and subzone, if both are secure, as described in Section 5. 2.3.5 Special Considerations with CNAME RRs There is a significant problem with security related RRs with the same owner name as a CNAME RR when retrieved from a non-security- aware server. In particular, an initial retrieval for the CNAME or any other type will not retrieve an associated signature, key, or NXT RR. For types other than CNAME it will retrieve that type at the target name of the CNAME (or chain of CNAMEs) and will return the CNAME as additional info. In particular, a specific retrieval for type SIG will not get the SIG, if any, at the original domain name but rather an SIG at the target name. In general, security aware servers must be used to securely CNAME in DNS. Security aware servers must (1) allow KEY, SIG, and NXT RRs along with CNAME RRs, (2) suppress CNAME processing on retrieval of these types as well as on retrieval of the type CNAME, and (3) automatically return SIG RRs authenticating the CNAME or CNAMEs encountered in resolving a query. Eastlake, Kaufman [Page 9] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 2.3.6 Signers Other Than The Zone There are two cases where a SIG resource record is signed by other than the zone private key. One is for support of dynamic update where an entity is permitted to authenticate/update its own records. The public key of the entity must be present in the DNS and be appropriately signed but the other RR(s) may be signed with the entity's key. The other is for support of transaction authentication as described in Section 2.4 below. 2.4 DNS Transaction Authentication The data origin authentication service described above protects resource records but provides no protection for DNS message headers. If header bits are falsely set by a server, there is little that can be done. However, it is possible to add transaction authentication. Such authentication means that a resolver can be sure it is at least getting messages from the server it thinks it queried, that the response is from the query it sent, and that these messages have not been diddled in transit. This is accomplished by optionally adding a special SIG resource record to the end of the reply which digitally signs the concatenation of the server's response and the resolver's query. The private key used belongs to the host composing the reply, not to the zone being queried. The corresponding public key is stored in and retrieved from the DNS. Because replies are highly variable, message authentication SIGs can not be pre-calculated. Thus it will be necessary to keep the private key on-line, for example in software or in a directly connected piece of hardware. DNS level transaction authentication will be unnecessary when IPSEC end-to-end security protocol is generally available [refernce IPSEC RFCs when RFC numbers assigned]. However, there will be a significant time during which there will be systems on which it will be hard to add such a protocol but relatively easy to replace the DNS components. Eastlake, Kaufman [Page 10] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 3. The KEY Resource Record The KEY resource record (RR) is used to document a key that is associated with a Domain Name System (DNS) name. It will be a public key as only public keys are stored in the DNS. This can be the public key of a zone, of a host or other end entity, or a user. A KEY RR is, like any other RR, authenticated by a SIG RR. Security aware DNS implementations MUST be designed to handle at least two simultaneously valid keys of the same type associated with a name. The type number for the KEY RR is 25. 3.1 KEY RDATA format The RDATA for a KEY RR consists of flags, a protocol octet, the algorithm number, and the public key itself. The format is as follows: 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | flags | protocol | algorithm | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | / / public key / / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| The meaning of the KEY RR owner name, flags, and protocol octet are described in Sections 3.2, 3.3 and 3.4 below respectively. The flags and protocol must be examined before any following data as they control the format and even whether there is any following data. The algorithm and public key fields are described in Section 3.5. The format of the public key is algorithm dependent. 3.2 Object Types, DNS Names, and Keys The public key in a KEY RR belongs to the object named in the owner name. This DNS name may refer to up to three different things. For example, dee.cybercash.com could be (1) a zone, (2) a host or other end entity , and (3) the mapping into a DNS name of the user or account dee@cybercash.com . Thus, there are flags in the KEY RR to indicate with which of these roles the owner name and public key are associated as described below. Eastlake, Kaufman [Page 11] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Although the same name can be used for up to all three of these contexts, such overloading of a name is discouraged. It is also possible to use the same key for different things with the same name or even different names, but this is strongly discouraged. In particular, the use of a zone key as a non-zone key will usually require that the private key be kept on line and thereby become much more vulnerable. It would be desirable for the growth of DNS to be managed so that additional possible simultaneous uses for names are NOT added. New uses should be distinguished by exclusive domains. For example, all IP autonomous system numbers have been mapped into the in-as.arpa domain [draft-ietf-dnssec-as-map-*.txt] and all telephone numbers in the world have been mapped into the tpc.int domain [RFC 1530]. This is much preferable to having the same name possibly be an autonomous system number, telephone number, and/or host as well as a zone and a user. In addition to the name type bits, there are additional control bits, the "no key" bit, the "experimental" bit, the "signatory" field, etc., as described below. 3.3 The KEY RR Flag Field In the "flags" field: Bit 0 is the "no key" bit. If this bit is on, there is no key information and the RR stops after the algorithm octet. By the use of this bit, a signed KEY RR can authenticatably assert that, for example, a zone is not secured. Bit 1 is the "experimental" bit. It is ignored if the "no key" bit is on and the following description assumes the "no key" bit to be off. Keys may be associated with zones, entities, or users for experimental, trial, or optional use, in which case this bit will be one. If this bit is a zero, it means that the use or availability of security based on the key is "mandatory". Thus, if this bit is off for a zone key, the zone should be assumed secured by SIG RRs and any responses indicating the zone is not secured should be considered bogus. If this bit is a one for a host or end entity, it might sometimes operate in a secure mode and at other times operate without security. The experimental bit, like all other aspects of the KEY RR, is only effective if the KEY RR is appropriately signed by a SIG RR. The experimental bit must be zero for safe secure operation and should only be a one for a minimal transition period. Bits 2-4 are reserved and must be zero. Eastlake, Kaufman [Page 12] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Bit 5 on indicates that this is a key associated with a "user" or "account" at an end entity, usually a host. The coding of the owner name is that used for the responsible individual mailbox in the SOA record: The owner name is the user name as the name of a node under the entity name. For example, "j.random_user" on host.subdomain.domain could have a public key associated through a KEY RR with name j\.random_user.host.subdomain.domain. It could be used in an security protocol where authentication of a user was desired. This key would be useful in IP or other security for a user level service such a telnet, ftp, rlogin, etc. Bit 6 on indicates that this is a key associated with the non- zone "entity" whose name is the RR owner name. This will commonly be a host but could, in some parts of the DNS tree, be some other type of entity such as a telephone number [RFC 1530]. This is the public key used in connection with the optional DNS transaction authentication service that can be used if the owner name is a DNS server host. It could also be used in an IP-security protocol where authentication of a host was desired such as routing, NTP, etc. Bit 7 is the "zone" bit and indicates that this is a zone key for the zone whose name is the KEY RR owner name. This is the fundamental type of DNS data origin authentication public key. Bit 8 is reserved to be the IPSEC bit and indicate that this key is valid for use in conjunction with the IP level security standard. This key could be used in connection with secured communication on behalf of an end entity or user whose name is the owner name of the KEY RR if the entity or user bits are on. The presence of a KEY resource with the IPSEC and entity bits on and experimental and no- key bits off is a guarantee that the host speaks IPSEC. Bit 9 is reserved to be the "email" bit and indicate that this key is valid for use in conjunction with MIME security multiparts. This key could be used in connection with secured communication on behalf of an end entity or user whose name is the owner name of the KEY RR if the entity or user bits are on. Bits 10-11 are reserved and must be zero. Bits 12-15 are the "signatory" field. If non-zero, it indicates that the key can validly sign RRs of the same name. If the owner name is a wildcard, then RRs with any name which is in the wildcard's scope can be signed. Fifteen different non-zero values are possible for this field and any differences in their meaning are reserved for definition in connection with DNS dynamic update or other new DNS commands. This field is meaningless for zone keys which always have authority to sign any RRs in the zone. The signatory field, like all other aspects of the KEY RR, is only effective if the KEY RR is appropriately signed by a SIG RR. Eastlake, Kaufman [Page 13] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 3.4 The Protocol Octet It is anticipated that keys stored in DNS will be used in conjunction with Internet protocols other than DNS (keys with zone bit or signatory field non-zero) and IPSEC (keys with IPSEC bit set). The protocol octet is provided to indicate that a key is valid for such use and, for end entity keys or the host part of user keys, that the secure version of that protocol is implemented on that entity or host. Values between 1 and 191 decimal inclusive are available for assignment by IANA for such protocols. The 63 values between 192 and 254 inclusive will not be assigned to a specific protocol and are available for experimental use under bilateral agreement. Value 0 indicates, for a particular key, that it is not valid for any particular additional protocol beyond those indicated in the flag field. And value 255 indicates that the key is valid for all assigned protocols (those in the 1 to 191 range). It is intended that new uses of DNS stored keys would initially be implemented, and operational experience gained, using the experimental range of the protocol octet. If demand for widespread deployment for the indefinite future warrants, a value in the assigned range would then be designated for the protocol. Finally, (1) should the protocol become so widespread in conjunction with other protocols which are indicated via the protocol octet and with which it shares key values that duplicate RRs are a serious burden and (2) should the protocol provide substantial facilities not available in any protocol for which a flags field bit has been allocated, then a flag field bit may be allocated to the protocol. Then a key can be simultaneously indicated as valid for that protocol and the entity or host can be simultaneously flagged as implementing the secure version of that protocol, along with other protocols for which flag field bits have been assigned. Note that the IPSEC protocol being developed may provide facilities adequate for all point to point IP communication meaning that additional flag field bits would only be assigned, when appropriate as indicated above, to protocols with a store-and-forward nature (other than DNS) or otherwise not subsumed into a point-to-point paradigm. 3.5 The KEY Algorithm Number and the MD5/RSA Algorithm This octet is the key algorithm parallel to the same field for the SIG resource. The MD5/RSA algorithm described in this draft is number 1. Numbers 2 through 252 are available for assignment should sufficient reason arise. However, the designation of a new algorithm Eastlake, Kaufman [Page 14] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 could have a major impact on interoperability and requires an IETF standards action. Number 254 is reserved for private use and will never be assigned a specific algorithm. For number 254, the public key area shown in the packet diagram above will actually begin with an Object Identifier (OID) indicating the private algorithm in use and the remainder of the area is whatever is required by that algorithm. Number 253 is reserved for use where the date or other labeling fields of SIGs are desired withouth any actual security. For number 253, the public key area is null. Values 0 and 255 are reserved. If the no key bit is zero and the algorithm field is 1, indicating the MD5/RSA algorithm, the public key field is structured as follows: 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | pub exp length| public key exponent / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | / +- modulus / | / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-/ To promote interoperability, the exponent and modulus are each limited to 2552 bits in length. The public key exponent is a variable length unsigned integer. Its length in octets is represented as one octet if it is in the range of 1 to 255 and by a zero octet followed by a two octet unsigned length if it is longer than 255 bytes. The public key modulus field is a multiprecision unsigned integer. The length of the modulus can be determined from the RDLENGTH and the preceding RDATA fields including the exponent. Leading zero bytes are prohibited in the exponent and modulus. 3.6 Interaction of Flags, Algorithm, and Protocol Bytes Various combinations of the no-key bit, algorithm byte, protocol byte, and any protocol indicating flags (such as the reserved IPSEC flag) are possible. (Note that the zone flag bit being on or the signatory field being non-zero is effectively a DNS protocol flag on.) The meaning of these combinations is indicated below: Eastlake, Kaufman [Page 15] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 NK = no key flag AL = alogrithm byte PR = protocols indicated by protocol byte or protocol flags x represents any valid non-zero value. AL PR NK Meaning 0 0 0 Illegal, claims key but has bad algorithm field. 0 0 1 Specifies total lack of security for owner. 0 x 0 Illegal, claims key but has bad algorithm field. 0 x 1 Specified protocols insecure, others may be secure. x 0 0 Useless. Gives key but no protocols to use it. x 0 1 Useless. Denies key but for no protocols. x x 0 Specifies key for protocols and certifies that those protocols are implemented with security. x x 1 Algorithm not understood for protocol. (remember, in reference to the above table, that a protocol byte of 255 means all protocols with protocol bytes assigned) 3.7 KEY RRs in the Construction of Responses An explicit request for KEY RRs does not cause any special additional information processing except, of course, for the corresponding SIG RR from a security aware server. Security aware DNS servers will include KEY RRs as additional information in responses where appropriate including the following: (1) On the retrieval of NS RRs, the zone key KEY RR(s) for the zone served by these name servers will be included as additional information. If not all additional info will fit, the KEY RR(s) have higher priority than type A (or AAAA) glue RRs. (2) On retrieval of type A (or AAAA) RRs, the end entity KEY RR(s) will be included. On inclusion of A (or AAAA) RRs as additional information, their KEY RRs will also be included but with lower priority than the relevant A (or AAAA) RRs. 3.8 File Representation of KEY RRs KEY RRs may appear as lines in a zone data file. The flag field, protocol, and algorithm number octets are then represented as unsigned integers. Note that if the "no key" flag is on in the flags or the algorithm specified is 253, nothing appears Eastlake, Kaufman [Page 16] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 after the algorithm octet. The remaining public key portion is represented in base 64 (see Appendix) and may be divided up into any number of white space separated substrings, down to single base 64 digits, which are concatenated to obtain the full signature. These substrings can span lines using the standard parenthesis. Note that the public key may have internal sub-fields but these do not appear in the master file representation. For example, with algorithm 1 there is a public exponent and then a modulus and with algorithm 254, there will be an OID followed by algorithm dependent information. Eastlake, Kaufman [Page 17] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 4. The SIG Resource Record The SIG or "signature" resource record (RR) is the fundamental way that data is authenticated in the secure Domain Name System (DNS). As such it is the heart of the security provided. The SIG RR unforgably authenticates other RRs of a particular type, class, and name and binds them to a time interval and the signer's domain name. This is done using cryptographic techniques and the signer's private key. The signer is frequently the owner of the zone from which the RR originated. 4.1 SIG RDATA Format The RDATA portion of a SIG RR is as shown below. The integrity of the RDATA information is protected by the signature field. 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | type covered | algorithm | labels | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | original TTL | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | signature expiration | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | time signed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | key footprint | / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ signer's name / / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | / +- signature / / / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The value of the SIG RR type is 24. The "type covered" is the type of the other RRs covered by this SIG. The algorithm number is an octet specifying the digital signature algorithm used parallel to the algorithm octet for the KEY RR. The MD5/RSA algorithm described in this draft is number 1. Numbers 2 through 252 are available for assignment should sufficient reason arise to allocate them. However, the designation of a new algorithm could have a major impact on the interoperability of the global DNS systems and requires an IETF standards action. Number 254 is Eastlake, Kaufman [Page 18] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 reserved for private use and will not be assigned a specific algorithm. For number 254, the "signature" area shown above will actually begin with an Object Identifier (OID) indicating the private algorithm in use and the remainder of the signature area is whatever is required by that algorithm. Number 253 is used when the time fields or other non-signature fields of the SIG are desired without any actual security. For number 253, the signature field will be null. Values 0 and 255 are reserved. The "labels" octet is an unsigned count of how many labels there are in the original SIG RR owner name not counting the null label for root and not counting any initial "*" for a wildcard. If a secured retrieval is the result of wild card substitution, it is necessary for the resolver to use the original form of the name in verifying the digital signature. This field helps optimize the determination of the original form reducing the effort in authenticating signed data. If, on retrieval, the RR appears to have a longer name than indicated by "labels", the resolver can tell it is the result of wildcard substitution. If the RR owner name appears to be shorter than the labels count, the SIG RR should be considered corrupt and ignored. The maximum number of labels possible in the current DNS is 127 but the entire octet is reserved and would be required should DNS names ever be expanded to 255 labels. The following table gives some examples. The value of "labels" is at the top, the retrieved owner name on the left, and the table entry is the name to use in signature verification except that "bad" means the RR is corrupt. labels= | 0 | 1 | 2 | 3 | 4 | --------+-----+------+--------+----------+----------+ .| . | bad | bad | bad | bad | d.| *. | d. | bad | bad | bad | c.d.| *. | *.d. | c.d. | bad | bad | b.c.d.| *. | *.d. | *.c.d. | b.c.d. | bad | a.b.c.d.| *. | *.d. | *.c.d. | *.b.c.d. | a.b.c.d. | The "original TTL" field is included in the RDATA portion to avoid (1) authentication problems that caching servers would otherwise cause by decrementing the real TTL field and (2) security problems that unscrupulous servers could otherwise cause by manipulating the real TTL field. This original TTL is protected by the signature while the current TTL field is not. NOTE: The "original TTL" must be restored into the covered RRs when the signature is verified. This implies that the RRs for a particular type need to all have the same TTL to start with. The SIG is valid until the "signature expiration" time which is an unsigned number of seconds since the start of 1 January 1970, GMT, Eastlake, Kaufman [Page 19] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 ignoring leap seconds. (See also Section 4.4.) SIG RRs should not have a date signed significantly in the future. To prevent misordering of network request to update a zone dynamically, monotonically increasing "time signed" dates are necessary. The "time signed" field is an unsigned number of seconds since the start of 1 January 1970, GMT, ignoring leap seconds. A SIG RR with an expiration date before the date signed is ineffective. The "key footprint" is a 16 bit quantity that is used to help efficiently select between multiple keys which may be applicable and as a quick check that a public key about to be used for the computationally expensive effort to check the signature is possibly valid. Its exact meaning is algorithm dependent. For the MD5/RSA algorithm, it is the next to the bottom two octets of the public key modulus needed to decode the signature field. That is to say, the most significant 16 of the lest significant 24 bits of this quantity in network order. The "signer's name" field is the domain name of the signer generating the SIG RR. This is frequently the zone which contained the RR(s) being authenticated. The signer's name may be compressed with standard DNS name compression when being transmitted over the network. The structure of the "signature" field is described below. 4.1.1 Signature Data Except for algorithm number 253 where it is null, the actual signature portion of the SIG RR binds the other RDATA fields to all of the "type covered" RRs with that owner name. These covered RRs are thereby authenticated. To accomplish this, a data sequence is constructed as follows: data = RDATA | RR(s)... where | is concatenation, RDATA is all the RDATA fields in the SIG RR itself before the signature, and RR(s) are all the RR(s) of the type covered with the same owner name and class as the SIG RR in canonical form and order. For purposes of DNS security, the canonical form for an RR is the RR with domain names (1) fully expanded (no name compression via pointers) and (2) all domain name letters set to lower case. Eastlake, Kaufman [Page 20] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 For purposes of DNS security, the canonical order for RRs is to sort them in ascending order by name, then by type, as left justified unsigned octet sequences in network (transmission) order where a missing octet sorts before a zero octet. (See also ordering discussion in Section 5.1.) Within any particular name and type they are similarly sorted by RDATA as a left justified unsigned octet sequence. EXCEPT that the type SIG RR(s) covering any particular type appear immediately after the other RRs of that type. Thus if at name a.b there is one A RR and one KEY RR, their order with SIGs for concatenating the "data" to be signed would be as follows: a.b. A .... a.b. SIG A ... a.b. KEY ... a.b. SIG KEY ... (SIGs on type ANY should not be included in a zone.) How this data sequence is processed into the signature is algorithm dependent. 4.1.2 MD5/RSA Algorithm Signature Calculation For the MD5/RSA algorithm, the signature is as follows hash = MD5 ( data ) signature = ( 01 | FF* | 00 | prefix | hash ) ** e (mod n) where MD5 is the message digest algorithm documented in RFC 1321, "|" is concatenation, "e" is the secret key exponent of the signer, and "n" is the public modulus of the signer's public key. 01, FF, and 00 are fixed octets of the corresponding hexadecimal value. "prefix" is the ASN.1 BER MD5 algorithm designator prefix specified in PKCS1, that is, hex 3020300c06082a864886f70d020505000410 [NETSEC]. The FF octet is repeated the maximum number of times such that the value of the quantity being exponentiated is one octet shorter than the value of n. The above specifications are exactly Public Key Cryptographic Standard #1 [PKCS1]. The size of n, including most and least significant bits (which will be 1) SHALL be not less than 512 bits and not more than 2552 bits. n and e SHOULD be chosen such that the public exponent is small. Leading zeros bytes are not permitted in the MD5/RSA algorithm Eastlake, Kaufman [Page 21] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 signature. A public exponent of 3 minimizes the effort needed to decode a signature. Use of 3 as the public exponent may be weak for confidentiality uses since, if the same data can be collected encrypted under three different keys with an exponent of 3 then, using the Chinese Remainder Theorem, the original plain text can be easily recovered. This weakness is not significant for DNS because we seek only authentication, not confidentiality. 4.1.3 Zone Transfer (AXFR) SIG The above SIG mechanisms assure the authentication of all zone signed RRs of a particular name, class and type. However, to efficiently secure complete zone transfers, a SIG RR owned by the zone name must be created with a type covered of AXFR that covers all zone signed RRs other than the SIG AXFR itself. It will be calculated by hashing together all other static zone RRs, including SIGs. The RRs are ordered and concatenated for hashing as described in Section 4.1.1. (See also ordering discussion in Section 5.1.) The AXFR SIG must be calculated last of all zone key signed SIGs in the zone. It really belongs to the zone as a whole, not to the zone name. The AXFR SIG is only retrieved as part of a zone transfer. After validation of the AXFR SIG, the zone may be considered valid without verification of all the internal zone SIGs in the zone; however, any SIGs signed by entity keys or the like must still be validated. The AXFR SIG is transmitted first in a zone transfer so the receiver can tell immediately that they may be able to avoid verifying other zone signed SIGs. Dynamic zone RRs which might be added by a dynamic zone update protocol and signed by an end entity or user key rather than a zone key (see Section 3.2) are not included in the AXFR SIG. They originate in the network and will not, in general, be migrated to the recommended off line zone signing procedure (see Section 8.2). Thus such dynamic RRs are not directly signed by the zone, are not included in the AXFR SIG, and are not generally protected against omission from zone transfers. 4.1.4 Transaction SIGs A response message from a security aware server may optionally contain a special SIG as the last item in the additional information section to authenticate the transaction. Eastlake, Kaufman [Page 22] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 This SIG has a "type covered" field of zero, which is not a valid RR type. It is calculated by using a "data" (see Section 4.1.2) of the entire preceding DNS reply message, including DNS header, concatenated with the entire DNS query message that produced this response, including the query's DNS header. That is data = full response (less final transaction SIG) | full query Verification of the transaction SIG (which is signed by the server host key, not the zone key) by the requesting resolver shows that the query and response were not tampered with in transit, that the response corresponds to the intended query, and that the response comes from the queried server. 4.2 SIG RRs in the Construction of Responses Security aware servers MUST, for every authoritative RR the query will return, attempt to send the available SIG RRs which authenticate the requested RR. The following rules apply to the inclusion of SIG RRs in responses: 1. when an RR is placed in a response, its SIG RR has a higher priority for inclusion than other RRs that may need to be included. If space does not permit its inclusion, the response MUST be considered truncated. 2. when a SIG RR is present for an RR to be included in the additional information section, the response MUST NOT be considered truncated if space does not permit the inclusion of the SIG RR. Sending SIGs to authenticate non-authoritative data (glue records and NS RRs for subzones) is unnecessary and must be avoided. Note that KEYs for subzones are authoritative. If a SIG covers any RR that would be in the answer section of the response, its automatic inclusion MUST be the answer section. If it covers an RR that would appear in the authority section, its automatic inclusion MUST be in the authority section. If it covers an RR that would appear in the additional information section it MUST appear in the additional information section. Optionally, DNS transactions may be authenticated by a SIG RR at the end of the response in the additional information section (Section 4.1.4). Such SIG RRs are signed by the DNS server originating the response. Although the signer field must be the name of the originating server host, the owner name, class, TTL, and original TTL, are meaningless. The class and TTL fields can be zero. To Eastlake, Kaufman [Page 23] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 conserve space, the owner name SHOULD be root (a single zero octet). If transaction authentication is desired, that SIG RR must be considered higher priority for inclusion than any other RR in the answer. 4.3 Processing Responses and SIG RRs The following rules apply to the processing of SIG RRs included in a response: 1. a security aware resolver that receives a response from what it believes to be a security aware server via a communication path that it believes to be secure with the AD bit (see Section 6.1) set, MAY choose to accept the RRs as received without verifying the SIG RRs. 2. in other cases, a security aware resolver SHOULD verify the SIG RRs for the RRs of interest. This may involve initiating additional queries for SIG or KEY RRs, at least in the case of getting a response from an insecure server. (As explained in 4.2 above, it will not be possible to secure CNAMEs being served up by non-secure resolvers.) NOTE: Implementors might expect the above SHOULD to be a MUST. However, local policy or the calling application may not require the security services. 3. If SIG RRs are received in response to a user query explicitly specifying the SIG type, no special processing is required. If the message does not pass reasonable checks or the SIG does not check against the signed RRs, the SIG RR is invalid and should be ignored. If all of the SIG RR(s) purporting to authenticate a set of RRs are invalid, then the set of RR(s) is not authenticated. If the SIG RR is the last RR in a response in the additional information section and has a type covered of zero, it is a transaction signature of the response and the query that produced the response. It MAY be optionally checked and the message rejected if the checks fail. But even if the checks succeed, such a transaction authentication SIG does NOT authenticate any RRs in the message. Only a proper SIG RR signed by the zone can authenticate RRs. If a resolver does not implement transaction SIGs, it MUST at least ignore them without error. If all reasonable checks indicate that the SIG RR is valid then RRs verified by it should be considered authenticated. Eastlake, Kaufman [Page 24] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 4.4 Signature Expiration, TTLs, and Validity Security aware servers must not consider SIG RRs to be authentic after their expiration time and not consider any RR to be authenticated after its signatures have expired. Within that constraint, servers should continue to follow DNS TTL aging. Thus authoritative servers should continue to follow the zone refresh and expire parameters and a non-authoritative server should count down the TTL and discard RRs when the TTL is zero. In addition, when RRs are transmitted in a query response, the TTL should be trimmed so that current time plus the TTL does not extend beyond the signature expiration time. Thus, in general, the TTL on an transmitted RR would be min(sigExpTim,max(zoneMinTTL,min(originalTTL,currentTTL))) 4.5 File Representation of SIG RRs A SIG RR can be represented as a single logical line in a zone data file [RFC1033] but there are some special considerations as described below. (It does not make sense to include a transaction authenticating SIG RR in a file as it is a transient authentication that covers data including an ephemeral transaction number so it must be calculated in real time by the DNS server.) There is no particular problem with the signer, covered type, and times. The time fields appears in the form YYYYMMDDHHMMSS where YYYY is the year, the first MM is the month number (01-12), DD is the day of the month (01-31), HH is the hour in 24 hours notation (00-23), the second MM is the minute (00-59), and SS is the second (00-59). The original TTL and algorithm fields appear as unsigned integers. If the original TTL, which applies to the type signed, is the same as the TTL of the SIG RR itself, it may be omitted. The date field which follows it is larger than the maximum possible TTL so there is no ambiguity. The "labels" field does not appear in the file representation as it can be calculated from the owner name. The key footprint appears as an unsigned decimal number. However, the signature itself can be very long. It is the last data field and is represented in base 64 (see Appendix) and may be divided up into any number of white space separated substrings, down to single base 64 digits, which are concatenated to obtain the full signature. These substrings can be split between lines using the Eastlake, Kaufman [Page 25] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 standard parenthesis. Eastlake, Kaufman [Page 26] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 5. Non-existent Names and Types The SIG RR mechanism described in Section 4 above provides strong authentication of RRs that exist in a zone. But is it not immediately clear how to authenticatably deny the existence of a name in a zone or a type for an existent name. The nonexistence of a name in a zone is indicated by the NXT ("next") RR for a name interval containing the nonexistent name. An NXT RR and its SIG are returned in the authority section, along with the error, if the server is security aware. The same is true for a non-existent type under an existing name. NXT RRs will also be returned if an explicit query is made for the NXT type. The existence of a complete set of NXT records in a zone means that any query for any name and type to a security aware server serving the zone will result in an reply containing at least one signed RR. NXT RRs do not appear in zone master files since they can be derived from the rest of the zone. 5.1 The NXT Resource Record The NXT resource record is used to securely indicate that RRs with an owner name in a certain name interval do not exist in a zone and to indicate what zone signed type RRs are present for an existing name. The owner name of the NXT RR is an existing name in the zone. It's RDATA is a "next" name and a type bit map. The presence of the NXT RR means that generally no name between its owner name and the name in its RDATA area exists and that no other types exist under its owner name. This implies a canonical ordering of all domain names in a zone. The ordering is to sort labels as unsigned left justified octet strings where the absence of a octet sorts before a zero octet and upper case letters are treated as lower case letters. Names are then sorted by sorting on the highest level label and then, within those names with the same highest level label by the next lower label, etc. Since we are talking about a zone, the zone name itself always exists and all other names are the zone name with some prefix of lower level labels. Thus the zone name itself always sorts first. There is a problem with the last NXT in a zone as it wants to have an owner name which is the last existing name in sort order, which is easy, but it is not obvious what name to put in its RDATA to indicate the entire remainder of the name space. This is handled by treating the name space as circular and putting the zone name in the RDATA of Eastlake, Kaufman [Page 27] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 the last NXT. There are special considerations due to interaction with wildcards as explained below. The NXT RRs for a zone should be automatically calculated and added to the zone by the same recommended off-line process that signs the zone. The NXT RR's TTL should not exceed the zone minimum TTL. 5.2 NXT RDATA Format The RDATA for an NXT RR consists simply of a domain name followed by a bit map. The type number for the NXT RR is 30. 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | next domain name / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | type bit map / +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The NXT RR type bit map is one bit per RR type present for the owner name similar to the WKS socket bit map. The first bit represents RR type zero (an illegal type which should not be present.) A one bit indicates that at least one RR of that type is present for the owner name. A zero indicates that no such RR is present. All bits not specified because they are beyond the end of the bit map are assumed to be zero. Note that bit 30, for NXT, will always be on so the minimum bit map length is actually four octets. The NXT bit map should be printed as a list of type mnemonics or decimal numbers similar to the WKS RR. The size of the bit map can be inferred from the RDLENGTH and the length of the next domain name. 5.3 Example Assume zone foo.tld has entries for big.foo.tld, medium.foo.tld. small.foo.tld. tiny.foo.tld. Eastlake, Kaufman [Page 28] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Then a query to a security aware server for huge.foo.tld would produce an error reply with the authority section data including something like the following: big.foo.tld. NXT medium.foo.tld. A MX SIG NXT big.foo.tld. SIG NXT 1 3 ( ;type-cov=NXT, alg=1, labels=3 19960102030405 ;signature expiration 19951211100908 ;time signed 2143658709 ;key footprint foo.tld. ;signer MxFcby9k/yvedMfQgKzhH5er0Mu/vILz45IkskceFGgiWCn/GxHhai6VAuHAoNUz4YoU 1tVfSCSqQYn6//11U6Nld80jEeC8aTrO+KKmCaY= ;signature (640 bits) ) Note that this response implies that big.foo.tld is an existing name in the zone and thus has other RR types associated with it than NXT. However, only the NXT (and its SIG) RR appear in the response to this query for huge.foo.tld, which is a non-existent name. 5.4 Interaction of NXT RRs and Wildcard RRs Since, in some sense, a wildcard RR causes all possible names in an interval to exist, there should not be an NXT RR that would cover any part of this interval. Thus if *.X.ZONE exists you would expect an NXT RR that ends at X.ZONE and one that starts with the last name covered by *.X.ZONE. However, this "last name covered" is something very ugly and long like \255\255\255....X.zone. So the NXT for the interval following is simply given the owner name *.X.ZONE. This "*" type name is not expanded when the NXT is returned as authority information in connection with a query for a non-existent name. If there could be any wildcard RRs in a zone and thus wildcard NXTs, care must be taken in interpreting the results of explicit NXT retrievals as the owner name may be a wildcard expansion. The existence of one or more wildcard RRs covering a name interval makes it possible for a malicious server to hide any more specificly named RRs in the internal. The server can just falsely return the wildcard match NXT instead of the more specificly named RRs. If there is a zone wide wildcard, there will be an NXT RR whose owner name is the wild card and whose RDATA is the zone name. In this case a server could conceal the existence of any more specific RRs in the zone. (It would be possible to design a more strict NXT feature which would eliminate this possibility. But it would be more complex and might be so constraining as to make any dynamic update feature that could create new names very difficult (see Section 3.2).) What name should be put into the RDATA of an NXT RR with an owner Eastlake, Kaufman [Page 29] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 name that is within a wild card scope? Since the "next" existing name will be one that matches the wild card, the wild card name should be used. Inclusion of such NXTs within a wild card scope is optional. 5.5 Blocking NXT Pseudo-Zone Transfers In a secure zone, a resolver can query for the initial NXT associated with the zone name. Using the next domain name RDATA field from that RR, it can query for the next NXT RR. By repeating this, it can walk through all the NXTs in the zone. If there are no wildcards, it can use this technique to find all names in a zone. If it does type ANY queries, it can incrementally get all information in the zone and perhaps defeat attempts to administratively block zone transfers. If there are any wildcards, this NXT walking technique will not find any more specific RR names in the part of the name space the wildcard covers. By doing explicit retrievals for wildcard names, a resolver could determine what intervals are covered by wildcards but still could not, with these techniques, find any names inside such intervals except by trying every name. If it is desired to block NXT walking, the recommended method is to add a zone wide wildcard of the KEY type with the no key bit on and with no type (zone, entity, or user) bit on. This will cause there to be one zone covering NXT RR and leak no information about what real names exist in the zone. This protection from pseudo-zone transfers is bought at the expense of eliminating the data origin authentication of the non-existence of names that NXT RRs can provide. If an entire zone is covered by a wildcard, a malicious server can return an RR produced by matching the resulting wildcard NXT and can thus hide all the real data and delegations with more specific names in the zone. 5.6 Special Considerations at Delegation Points A name other than root which is the head of a zone also appears as the leaf in a superzone. If both are secure, there will always be two different NXT RRs with the same name. They can be distinguished by their signers and next domain name fields. Security aware servers should return the correct NXT automatically when required to authenticate the non-existence of a name and both NXTs, if available, on explicit query for type NXT. Insecure servers will never automatically return an NXT and may only return the NXT from the subzone on explicit queries. Eastlake, Kaufman [Page 30] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 6. The AD and CD Bits and How to Resolve Securely Retrieving or resolving authentic data from the Domain Name System (DNS) involves starting with one or more trusted public keys. With trusted keys, a resolver willing to perform cryptography can progress securely through the secure DNS zone structure to the zone of interest as described in Section 6.3. Such trusted public keys would normally be configured in a manner similar to that described in Section 6.2. However, as a practical matter, a security aware resolver would still gain some confidence in the results it returns even if it was not configured with any keys but trusted what it got from a local well known server as a starting point. Data stored at a server needs security labels of Authenticated, Pending, or Insecure. There is also a fourth transient state of Bad which indicates that SIG checks have explicitly failed on the data. Such Bad data is not retained at a security aware server. Authenticated means that the data has a valid SIG under a KEY traceable via a chain of zero or more SIG and KEY RRs to a KEY configured at the resolver via its boot file. Pending data has no authenticated SIGs and at least one additional SIG the resolver is still trying to authenticate. Insecure data is data which it is known can never be either Authenticated or found Bad because it is in a zone with no key or an experimental key. Behavior in terms of control of and flagging based on such data labels is described in Section 6.1. The proper validation of signatures requires a reasonably secure shared opinion of the absolute time between resolvers and servers as described in Section 6.4. In getting to the data of interest to respond to a query, a secure resolver may encounter genuine non-secure zones. It may proceed through such zones but should report this as described in Section 6.5. 6.1 The AD and CD Header Bits Two unused bits are allocated out of the DNS query/response format header. The AD (authentic data) bit indicates in a response that the data included has been verified by the server providing it. The CD (checking disabled) bit indicates in a query that non-verified data is acceptable to the resolver sending the query. These bits are allocated from the must-be-zero Z field as follows: Eastlake, Kaufman [Page 31] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 1 1 1 1 1 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ID | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |QR| Opcode |AA|TC|RD|RA| Z|AD|CD| RCODE | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | QDCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ANCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | NSCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ | ARCOUNT | +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ These bits are zero in old servers and resolvers. Thus the responses of old servers are not flagged as authenticated to security aware resolvers and queries from non-security aware resolvers do not assert the checking disabled bit and thus will be answered by security aware servers only with authenticated data. Of course security aware resolvers can not trust the AD bit unless they trust the server they are talking to and have a secure path to it. Any security aware resolver willing to do cryptography should assert the CD bit on all queries to reduce DNS latency time by allowing security aware servers to answer before they have resolved the validity of data. Security aware servers never return Bad data. For non-security aware resolvers or security aware resolvers requesting service by having the CD bit clear, security aware servers return only Authenticated or Insecure data with the AD bit set in the response. Security aware resolvers will know that if data is Insecure versus Authentic by the absence of SIG RRs. Security aware servers may return Pending data to security aware resolvers requesting the service by clearing the AD bit in the response. The AD bit may only be set on a response if the RRs in the response are either Authenticated or Insecure. 6.2 Boot File Format The format for a boot file directive to configure a starting zone key is as follows: pubkey name flags protocol algorithm key-data for a public key. "name" is the owner name (if the line is translated into a KEY RR). Flags indicates the type of key and is Eastlake, Kaufman [Page 32] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 the same as the flag octet in the KEY RR. Algorithm is the algorithm in use where one is the MD5/RSA algorithm and 254 indicates a private algorithm. The material after the algorithm is algorithm dependent and, for private algorithms, starts with the algorithm's identifying OID. If the "no key" bit is on in flags or the algorithm is specified as 253, then the key-data after algorithm may be omitted. It is treated as an octet stream and encoded in base 64 (see Appendix). A file of keys for cross certification or other purposes can be configured though the keyfile directive as follows: keyfile filename The file looks like a master file except that it can only contain KEY and SIG RRs with the SIGs signed under a key configured with the pubkey directive. While it might seem logical for everyone to start with the key for the root zone, this has problems. The logistics of updating every DNS resolver in the world when the root key changes would be excessive. It may be some time before there even is a root key. Furthermore, many organizations will explicitly wish their "interior" DNS implementations to completely trust only their own zone. These interior resolvers can then go through the organization's zone server to access data outsize the organization's domain. 6.3 Chaining Through Zones Starting with one or more trusted keys for a zone, it should be possible to retrieve signed keys for its subzones which have a key and, if the zone is not root, for some superzone. Every authoritative secure zone server should also include the KEY RR for a super-zone signed by the secure zone via a keyfile directive. This makes it possible to climb the tree of zones if one starts below root. A secure sub-zone is indicated by a KEY RR appearing with the NS RRs for the sub-zone. These make it possible to descend within the tree of zones. A resolver should keep track of the number of successive secure zones traversed from a starting point to any secure zone it can reach. In general, the lower such a distance number is, the greater the confidence in the data. Data configured via a boot file directive should be given a distance number of zero. Should a query encounter different data for the same query with different distance values, that with a larger value should be ignored. A security conscious resolver should completely refuse to step from a Eastlake, Kaufman [Page 33] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 secure zone into a non-secure zone unless the non-secure zone is certified to be non-secure, or only experimentally secure, by the presence of an authenticated KEY RR for the non-secure zone with a no key flag or the presence of a KEY RR with the experimental bit set. Otherwise the resolver is probably getting completely bogus or spoofed data. If legitimate non-secure zones are encountered in traversing the DNS tree, then no zone can be trusted as secure that can be reached only via information from such non-secure zones. Since the non-secure zone data could have been spoofed, the "secure" zone reach via it could be counterfeit. The "distance" to data in such zones or zones reached via such zones could be set to 512 or more as this exceeds the largest possible distance through secure zones in the DNS. Nevertheless, continuing to apply secure checks within "secure" zones reached via non-secure zones will, as a practical matter, provide some increase in security. 6.4 Secure Time Coordinated interpretation of the time fields in SIG RRs requires that reasonably consistent time be available to the hosts implementing the DNS security extensions. A variety of time synchronization protocols exist including the Network Time Protocol (NTP, RFC1305). If such protocols are used, they should be used securely so that time can not be spoofed. Otherwise, for example, a host could get its clock turned back and might then believe old SIG and KEY RRs which were valid but no longer are. Eastlake, Kaufman [Page 34] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 7. Operational Considerations This section discusses a variety of considerations in secure operation of the Domain Name System (DNS) using these proposed protocol extensions. 7.1 Key Size Considerations There are a number of factors that effect public key size choice for use in the DNS security extension. Unfortunately, these factors usually do not all point in the same direction. Choice of zone key size should generally be made by the zone administrator depending on their local conditions. For most schemes, larger keys are more secure but slower. Given a small public exponent, verification (the most common operation) for the MD5/RSA algorithm will vary roughly with the square of the modulus length, signing will vary with the cube of the modulus length, and key generation (the least common operation) will vary with the fourth power of the modulus length. The current best algorithms for factoring a modulus and breaking RSA security vary roughly with the square of the modulus itself. Thus going from a 640 bit modulus to a 1280 bit modulus only increases the verification time by a factor of 4 but increases the work factor of breaking the key by over 2^3000. [RSA FAQ] An upper bound of 2552 bit has been established for the MD4/RSA DNS security algorithm for interoperability purposes. However, larger keys increase the size of the KEY and SIG RRs. This increases the chance of DNS UDP packet overflow and the possible necessity for using higher overhead TCP in responses. The recommended minimum RSA algorithm modulus size, 640 bits, is believed by the authors to be secure at this time and for some years but high level zones in the DNS tree may wish to set a higher minimum, perhaps 1000 bits, for security reasons. (Since the United States National Security Agency generally permits export of encryption systems using an RSA modulus of up to 512 bits, use of that small a modulus, i.e. n, must be considered weak.) For a key used only to secure data and not to secure other keys, 640 bits should be entirely adequate. Eastlake, Kaufman [Page 35] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 7.2 Key Storage It is strongly recommended that zone private keys and the zone file master copy be kept and used in off-line non-network connected physically secure machines only. Periodically an application can be run to re-sign the RRs in a zone by adding NXT and SIG RRs. Then the augmented file can be transferred, perhaps by sneaker-net, to the networked zone primary server machine. The idea is to have a one way information flow to the network to avoid the possibility of tampering from the network. Keeping the zone master file on-line on the network and simply cycling it through an off-line signer does not do this. The on-line version could still be tampered with if the host it resides on is compromised. For maximum security, the master copy of the zone file should be off net and should not be updated based on an unsecured network mediated communication. Note, however, that secure resolvers need to be configured with some trusted on-line public key information (or a secure path to such a resolver). Non-zone private keys, such as host or user keys, may have to be kept on line to be used for real-time purposes such as DNS transaction security, IPSEC session set-up, or secure mail. 7.3 Key Generation Careful key generation is a sometimes overlooked but absolutely essential element in any cryptographically secure system. The strongest algorithms used with the longest keys are still of no use if an adversary can guess enough to lower the size of the likely key space so that it can be exhaustively searched. Suggestions will be found in RFC 1750. It is strongly recommended that key generation also occur off-line, perhaps on the machine used to sign zones (see Section 7.2). 7.4 Key Lifetimes No key should be used forever. The longer a key is in use, the greater the probability that it will have been compromised through carelessness, accident, espionage, or cryptanalysis. Furthermore, if key rollover is a rare event, there is an increased risk that, when the time does come up change the key, no one at the site will remember how to do it or other problems will have developed in the Eastlake, Kaufman [Page 36] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 procedures. While key lifetime is a matter of local policy, these considerations suggest that no zone key should have a lifetime significantly over four years. A reasonable maximum lifetime for zone keys that are kept off-line and carefully guarded is 13 months with the intent that they be replaced every year. A reasonable maximum lifetime for end entity keys that are used for IP-security or the like and are kept on line is 36 days with the intent that they be replaced monthly or more often. In some cases, an entity key lifetime of somewhat over a day may be reasonable. 7.5 Signature Lifetime Signature expiration times must be set far enough in the future that it is quite certain that new signatures can be generated before the old ones expire. However, setting expiration too far into the future could, if bad data or signatures were ever generated, mean a long time to flush such badness. It is recommended that signature lifetime be a small multiple of the TTL but not less than a reasonable re-signing interval. 7.6 Root It should be noted that in DNS the root is a zone unto itself. Thus the root zone key should only be seen signing itself or signing RRs with names one level below root, such as .aq, .edu, or .arpa. Implementations MAY reject as bogus any purported root signature of records with a name more than one level below root. Eastlake, Kaufman [Page 37] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 8. Conformance Several levels of server and resolver conformance are defined. 8.1 Server Conformance Two levels of server conformance are defined as follows: Minimal server compliance is the ability to store and retrieve (including zone transfer) SIG, KEY, and NXT RRs. Any secondary, caching, or other server for a secure zone must be at least minimally compliant and even then some things, such as secure CNAMEs, will not work. Full server compliance adds the following to basic compliance: (1) ability to read SIG, KEY, and NXT RRs in zone files and (2) ability, given a zone file and private key, to add appropriate SIG and NXT RRs, possibly via a separate application, (3) proper automatic inclusion of SIG, KEY, and NXT RRs in responses, (4) suppression of CNAME following on retrieval of the security type RRs, (5) recognize the CD query header bit and set the AD query header bit, as appropriate, and (6) proper handling of the two NXT RRs at delegation points. Primary servers for secure zones MUST be fully compliant and for completely successful secure operation, all secondary, caching, and other servers handling the zone should be fully compliant as well. 8.2 Resolver Conformance Two levels of resolver compliance are defined: A basic compliance resolver can handle SIG, KEY, and NXT RRs when they are explicitly requested. A fully compliant resolver (1) understands KEY, SIG, and NXT RRs, (2) maintains appropriate information in its local caches and database to indicate which RRs have been authenticated and to what extent they have been authenticated, (3) performs additional queries as necessary to attempt to obtain KEY, SIG, or NXT RRs from non- security aware servers, (4) normally sets the CD query header bit on its queries. Eastlake, Kaufman [Page 38] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 9. Security Considerations This document concerns technical details of extensions to the Domain Name System (DNS) protocol to provide data integrity and origin authentication, public key distribution, and optional transaction security. If should be noted that, at most, these extensions guarantee the validity of resource records, including KEY resource records, retrieved from the DNS. They do not magically solve other security problems. For example, using secure DNS you can have high confidence in the IP address you retrieve for a host name; however, this does not stop someone for substituting an unauthorized host at that address or capturing packets sent to that address and falsely responding with packets apparently from that address. Any reasonably complete security system will require the protection of many other facets of the Internet. References [NETSEC] - Network Security: PRIVATE Communications in a PUBLIC World, Charlie Kaufman, Radia Perlman, & Mike Speciner, Prentice Hall Series in Computer Networking and Distributed Communications 1995. [PKCS1] - PKCS #1: RSA Encryption Standard, RSA Data Security, Inc., 3 June 1991, Version 1.4. [RFC1032] - Domain Administrators Guide, M. Stahl, November 1987 [RFC1033] - Domain Administrators Operations Guide, M. Lottor, November 1987 [RFC1034] - Domain Names - Concepts and Facilities, P. Mockapetris, November 1987 [RFC1035] - Domain Names - Implementation and Specifications [RFC1305] - Network Time Protocol (v3), D. Mills, April 9 1992. [RFC1321] - The MD5 Message-Digest Algorithm, R. Rivest, April 16 1992. [RFC1530] - Principles of Operation for the TPC.INT Subdomain: General Principles and Policy, C. Malamud, M. Rose, October 6 1993. [RFC1750] - Randomness Requirements for Security, D. Eastlake, S. Crocker, J. Schiller, December 1994. Eastlake, Kaufman [Page 39] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 [RSA FAQ] - RSADSI Frequently Asked Questions periodic posting. Eastlake, Kaufman [Page 40] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Authors Addresses Donald E. Eastlake, 3rd CyberCash, Inc. 318 Acton Street Carlisle, MA 01741 USA Telephone: +1 508 287 4877 EMail: dee@cybercash.com Charles W. Kaufman Iris Associates 1 Technology Park Drive Westford, MA 01886 USA Telephone: +1 508-392-5276 EMail: charlie_kaufman@iris.com Expiration and File Name This draft expires 2 April 1995. Its file name is draft-ietf-dnssec-secext-06.txt. Eastlake, Kaufman [Page 41] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 Appendix: Base 64 Encoding The following encoding technique is taken from RFC 1521 by Borenstein and Freed. It is reproduced here in an edited form for convenience. A 65-character subset of US-ASCII is used, enabling 6 bits to be represented per printable character. (The extra 65th character, "=", is used to signify a special processing function.) The encoding process represents 24-bit groups of input bits as output strings of 4 encoded characters. Proceeding from left to right, a 24-bit input group is formed by concatenating 3 8-bit input groups. These 24 bits are then treated as 4 concatenated 6-bit groups, each of which is translated into a single digit in the base64 alphabet. Each 6-bit group is used as an index into an array of 64 printable characters. The character referenced by the index is placed in the output string. Table 1: The Base64 Alphabet Value Encoding Value Encoding Value Encoding Value Encoding 0 A 17 R 34 i 51 z 1 B 18 S 35 j 52 0 2 C 19 T 36 k 53 1 3 D 20 U 37 l 54 2 4 E 21 V 38 m 55 3 5 F 22 W 39 n 56 4 6 G 23 X 40 o 57 5 7 H 24 Y 41 p 58 6 8 I 25 Z 42 q 59 7 9 J 26 a 43 r 60 8 10 K 27 b 44 s 61 9 11 L 28 c 45 t 62 + 12 M 29 d 46 u 63 / 13 N 30 e 47 v 14 O 31 f 48 w (pad) = 15 P 32 g 49 x 16 Q 33 h 50 y Special processing is performed if fewer than 24 bits are available at the end of the data being encoded. A full encoding quantum is always completed at the end of a quantity. When fewer than 24 input bits are available in an input group, zero bits are added (on the right) to form an integral number of 6-bit groups. Padding at the end of the data is performed using the '=' character. Since all base64 input is an integral number of octets, only the following cases can arise: (1) the final quantum of encoding input is an integral multiple of 24 bits; here, the final unit of encoded output will be an integral multiple of 4 characters with no "=" padding, (2) Eastlake, Kaufman [Page 42] INTERNET-DRAFT DNS Protocol Security Extensions 3 October 1995 the final quantum of encoding input is exactly 8 bits; here, the final unit of encoded output will be two characters followed by two "=" padding characters, or (3) the final quantum of encoding input is exactly 16 bits; here, the final unit of encoded output will be three characters followed by one "=" padding character. Eastlake, Kaufman [Page 43]   Received: from relay.tis.com by neptune.TIS.COM id aa03387; 6 Oct 95 12:51 EDT Received: from tce.ing.uniroma1.it(151.100.8.30) by relay.tis.com via smap (g3.0.1) id xma020436; Fri, 6 Oct 95 12:33:30 -0400 Received: from labmicrolc.ing.uniroma1.it by tce.ing.uniroma1.it (AIX 3.2/UCB 5.64/4.03) id AA12382; Fri, 6 Oct 1995 16:56:31 +0200 Message-Id: <9510061456.AA12382@tce.ing.uniroma1.it> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Date: Fri, 6 Oct 1995 17:16:20 +0100 To: ieeetcpc@ccvm.sunysb.ed, utheorynt@vm1.nodak.edu, orcs-l@osuvm1.bitnet, tccc@cs.umass.edu, cellular@dfv.rwth-aachen.edu, performance@tay1.dec.com, glynn@leland.stanford.edu, modern-heuristics@uk.ac.mailbase, ietf-announce@cnri.reston.va.us, mobile-ip@tadpole.com, dbworld@cs.wisc.edu, end2end-interest@isi.edu, f-troup@aurora.cis.upenn.edu, rem-conf-request@es.net, cost237-transport@comp.lancs.ac.uk, reres@laas.fr, hipparch@sophia.inria.fr, xtp-relay@cs.concordia.ca, rem-conf@es.net, sigmedia@bellcore.com, www-security@ns2.Rutgers.EDU, ipsec@ans.net, dns-security@TIS.COM, mobile-ip@tadpole.com, arpanet-bboard@mc.lcs.mit.edu, atm@bbn.com, cnom@meatro.bellcore.com, globecom@signet.com.sig, ietf@isi.edu, elf@cs.washington.edu, g_f_wetzel@att.com From: Paolo Bernardi Subject: Wireless Networks Journal - CFP Herebelow it follows the call for papers for a special issue of Wireless Networks Journal. I would be very grateful if you could diffuse it according your distribution list. Thank you for your kind attention. Call for Papers WIRELESS NETWORKS JOURNAL Baltzer Science Publishers Special Issue "Exposure Hazards and Health Protection in Personal Communication Services" Scope: The rapid diffusion of electronic and telecommunication equipments and systems emitting electromagnetic waves has brought into focus the problems of electromagnetic pollution of the environment and the possible adverse health effects on human beings. In particular, over the past decade there has been a significant increase in the use of hand-held cellular telephones. Because of the proximity of the transmitting antenna to the user's head, great concerns have arose about the potential risks to human health. The problem has been made even more acute by the impending development of wireless data services and wide-band wireless local area networks. Many national and international standard organizations, governmental bodies, and health authorities have issued or are considering approval of standards, recommendations, or legistative actions to protect the public from excessive exposures. In the meantime, scientists and manufacturers are contemplating new design techniques that may reduce the exposure. The aim of this special issue is to highlight problems which are presently under consideration and to present recent progress in this area of research, with particular emphasis on scientific studies used to define exposure limits. Possible topics include, but are not limited to: Biological effects (in vitro and in vivo): - CW fields - modulated fields Dosimetry: - source characterization - electric and magnetic properties of biological materials - experiments and numerical models Epidemiology Interaction mechanisms: - at subcellular, cellular, single organ, and physiological system level Standards and Safety Issues: - cellular phones - wireless data systems and services - wireless local-area networks - Video Display Units The authors should send 4 copies of their paper to one of the Guest Editors by February 1, 1996. The following time-table shall be followed: Manuscript Submission: Deadline: February 1, 1996 Final Manuscript Submission after Revision: Deadline: July 1, 1996 Expected Publication Date: xx, xx, xx Guest Editors: Prof. Paolo Bernardi Department of Electronic Engineering Universita' di Roma "La Sapienza" Via Eudossiana 18, 00184 Roma, ITALY Tel. +39 6 4458 5 855 Fax +39 6 4742647 e-mail: bernardi@tce.ing.uniroma1.it Prof. James C. Lin The University of Illinois at Chicago College of Engineering (M/C 154) 851 South Morgan Street Chicago, Illinois 60607 - 7053 tel: +312 413 1052 fax: +312 413 0024 e-mail: u45339@uicvm.uic.edu Prof. Paolo Bernardi Department of Electronic Engineering Universita' di Roma "La Sapienza" Via Eudossiana 18, 00184 Roma ITALY Tel. +39 6 4458 5 855 Fax +39 6 4742647 E-mail bernardi@tce.ing.uniroma1.it   Received: from relay.tis.com by neptune.TIS.COM id aa10153; 10 Oct 95 9:50 EDT Received: from watson.ibm.com(129.34.139.4) by relay.tis.com via smap (g3.0.1) id xma023195; Tue, 10 Oct 95 09:33:38 -0400 Received: from WATSON by watson.ibm.com (IBM VM SMTP V2R3) with BSMTP id 2663; Tue, 10 Oct 95 09:51:45 EDT Received: from YKTVMV by watson.vnet.ibm.com with "VAGENT.V1.02 on VAGENT2" id 1919; Tue, 10 Oct 1995 09:51:43 EDT Received: from edisto.watson.ibm.com by yktvmv.watson.ibm.com (IBM VM SMTP V2Rx) with TCP; Tue, 10 Oct 95 09:51:42 EDT Received: by edisto.watson.ibm.com (AIX 3.2/UCB 5.64/900524) id AA19385; Tue, 10 Oct 1995 09:52:16 -0400 Message-Id: <9510101352.AA19385@edisto.watson.ibm.com> X-External-Networks: yes To: "Donald E. Eastlake 3rd" Cc: dns-security@TIS.COM, jis@mit.edu, yakov@cisco.com, set@thumper.bellcore.com, randy@psg.com Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: Your message of Tue, 03 Oct 95 21:51:52 D. Date: Tue, 10 Oct 95 09:52:16 -0500 From: "Edie E. Gunter" I have a few comments on the draft... - Section 3 says: Security aware DNS implementations MUST be designed to handle at least two simultaneously valid keys of the same type associated with a name. Why isn't the ability to handle one enough? Why MUST two valid keys be supported? Optional support of more than one is fine. (Why would anyone want more than one KEY of the same type, anyway?) - Section 3.7 refers to type AAAA RR's. What are these? - Section 4 says: The SIG RR unforgably authenticates other RRs of a particular type, class, and name and binds them to a time interval and the signer's domain name. If this is true, why isn't the SIG on a dynamic update sufficient to make that name/RR a full-fledged part of the DNS database, allowing dynamically updated data to be treated just like "static" data? If this is true, why do we even need the distinction of static versus dynamic RRs? - Section 4.1.3 says: Thus such dynamic RRs are not directly signed by the zone, are not included in the AXFR SIG, and are not generally protected against omission from zone transfers. I am quite sure this is not what anyone running a secure DNS that supports secure dynamic updates would want. It seems this section should cover how to securely include dynamic updates in a zone transfer -- if not via the method described in 4.1.3 using AXFR SIG, etc. then by some other method. - Section 4.3 says: Only a proper SIG RR signed by the zone can authenticate RRs. What about entity signed dynamic RRs? - Section 4.4 Signature Expiration When a SIG expires, the covered RR's are not removed from the database, but are kept around and the AD bit is used to indicate if the data is no longer authentic. Is that right? - Section 5.1 says: The NXT RRs for a zone should be automatically calculated and added to the zone by the same recommended off-line process that signs the zone. What about dynamic updates? Can't you get into a situation where something was added via a dynamic update and the NXT RR computed at start-up is no longer correct? It seems to me that these NXT RR's must be computed on the fly to be accurate in the face of dynamic updates. - Section 6 says: Authenticated means that the data has a valid SIG under a KEY traceable via a chain of zero or more SIG and KEY RRs to a KEY configured at the resolver via its boot file. So, if the KEY RR for a name was in the statically read master file for the zone, then RR's added dynamically and signed with the private part of that KEY are considered authenticated? - Section 6.1 says: Security aware servers never return Bad data. Is this true, given that zone transfers may omit dynamically added RR's and given that NXT RR's are calculated offline? Perhaps I don't understand the definition of Bad data here. - Section 6.3 says: A resolver should keep track of the number of successive secure zones traversed from a starting point to any secure zone it can reach. <...> Should a query encounter different data for the same query with different distance values, that with a larger value should be ignored. I don't see exactly how this is supposed to work. Are you suggesting that after sending out a query, the client waits around for multiple query responses and then picks the one with the lower distance value? In practice, wouldn't a client just take the first response with a non-empty answer section and use that? - Section 7.2 says: Periodically an application can be run to re-sign the RRs in a zone by adding NXT and SIG RRs. It seems to get dynamic updates to work within the DNSSEC framework, this period would have to be such that everything is re-signed after each dynamic update. The update becomes part of the "static" data and all the "static" data is then resigned. No, this can't be right. - Section 7.5 says: It is recommended that signature lifetime be a small multiple of the TTL but not less than a reasonable re-signing interval. In an environment where DHCP is used to hand out IP address leases and DNS is updated dynamically to reflect the lease information, the lifetime of the data will usually be that of the lease duration. In the case of mobile clients, this lease duration may be just 5 - 10 minutes. That said, what is your idea of a reasonable re-signing interval? - Also, it was mentioned to me in private email that: if you want a completely dynamic zone, you can just have the zone key sign an entity key with wildcard authority over the entire zone and then use the entity key for everything in the zone I don't see anything like this discussed in the draft -- particularly with respect to zone transfers and handling NXT records. (And if there really is this other way to do security in DNS servers that support dynamic updates, I'd really like to understand how it would work!) Edie   Received: from relay.tis.com by neptune.TIS.COM id aa11791; 10 Oct 95 11:06 EDT Received: from concorde.inria.fr(192.93.2.39) by relay.tis.com via smap (g3.0.1) id xma024184; Tue, 10 Oct 95 10:49:14 -0400 Received: from givry.inria.fr (givry.inria.fr [128.93.8.18]) by concorde.inria.fr (8.6.10/8.6.9) with ESMTP id QAA00243; Tue, 10 Oct 1995 16:00:31 +0100 Received: from givry.inria.fr (localhost.inria.fr [127.0.0.1]) by givry.inria.fr (8.6.10/8.6.6) with ESMTP id QAA03251; Tue, 10 Oct 1995 16:00:30 +0100 Message-Id: <199510101500.QAA03251@givry.inria.fr> From: Francis Dupont To: "Edie E. Gunter" cc: "Donald E. Eastlake 3rd" , dns-security@TIS.COM, jis@mit.edu, yakov@cisco.com, set@thumper.bellcore.com, randy@psg.com Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-reply-to: Your message of Tue, 10 Oct 1995 09:52:16 EST. <9510101352.AA19385@edisto.watson.ibm.com> Date: Tue, 10 Oct 1995 16:00:26 +0100 Sender: Francis.Dupont@inria.fr In your previous mail you wrote: I have a few comments on the draft... - Section 3.7 refers to type AAAA RR's. What are these? => RR for IPv6 addresses (the name is from the proposed AA RR for SIP 8 byte addresses). Regards Francis.Dupont@inria.fr PS: according to draft-ietf-ipngwg-dns-00.txt: The AAAA resource record type is a new record specific to the Inter- net class that stores a single IPv6 address. The value of the type is 28 (decimal). An IPv6 address is encoded in the data portion of an AAAA resource record in network byte order (high-order byte first). (PS: IPv6 addresses have a 16 byte length)   Received: from relay.tis.com by neptune.TIS.COM id aa01490; 11 Oct 95 10:34 EDT Received: from ietf.cnri.reston.va.us(132.151.1.35) by relay.tis.com via smap (g3.0.1) id xma008094; Wed, 11 Oct 95 10:17:07 -0400 Received: from [127.0.0.1] by IETF.CNRI.Reston.VA.US id aa10936; 11 Oct 95 9:26 EDT Mime-Version: 1.0 Content-Type: Multipart/Mixed; Boundary="NextPart" To: IETF-Announce: ;, tis.com@TIS.COM MMDF-Warning: Parse error in original version of preceding line at neptune.TIS.COM cc: dns-security@TIS.COM From: Internet-Drafts@cnri.reston.va.us Reply-to: Internet-Drafts@cnri.reston.va.us Subject: I-D ACTION:draft-ietf-dnssec-secext-06.txt Date: Wed, 11 Oct 95 09:26:09 -0400 Sender: cclark@cnri.reston.va.us Message-ID: <9510110926.aa10936@IETF.CNRI.Reston.VA.US> --NextPart A Revised Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Domain Name System Security Working Group of the IETF. Title : Domain Name System Security Extensions Author(s) : D. Eastlake, C. Kaufman Filename : draft-ietf-dnssec-secext-06.txt Pages : 43 Date : 10/10/1995 The Domain Name System (DNS) has become a critical operational part of the Internet infrastructure yet it has no strong security mechanisms to assure data integrity or authentication. Extensions to the DNS are described that provide these services to security aware resolvers or applications through the use of cryptographic digital signatures. These digital signatures are included in secured zones as resource records. Security can still be provided even through non-security aware DNS servers in many cases. The extensions also provide for the storage of authenticated public keys in the DNS. This storage of keys can support general public key distribution service as well as DNS security. The stored keys enable security aware resolvers to learn the authenticating key of zones in addition to keys for which they are initially configured. Keys associated with DNS names can be retrieved to support other protocols. Provision is made for a variety of key types and algorithms. In addition, the security extensions provide for the optional authentication of DNS protocol transactions. Internet-Drafts are available by anonymous FTP. Login with the username "anonymous" and a password of your e-mail address. After logging in, type "cd internet-drafts" and then "get draft-ietf-dnssec-secext-06.txt". A URL for the Internet-Draft is: ftp://ds.internic.net/internet-drafts/draft-ietf-dnssec-secext-06.txt Internet-Drafts directories are located at: o Africa Address: ftp.is.co.za (196.4.160.8) o Europe Address: nic.nordu.net (192.36.148.17) Address: ftp.nis.garr.it (192.12.192.10) o Pacific Rim Address: munnari.oz.au (128.250.1.21) o US East Coast Address: ds.internic.net (198.49.45.10) o US West Coast Address: ftp.isi.edu (128.9.0.32) Internet-Drafts are also available by mail. Send a message to: mailserv@ds.internic.net. In the body type: "FILE /internet-drafts/draft-ietf-dnssec-secext-06.txt". NOTE: The mail server at ds.internic.net can return the document in MIME-encoded form by using the "mpack" utility. To use this feature, insert the command "ENCODING mime" before the "FILE" command. To decode the response(s), you will need "munpack" or a MIME-compliant mail reader. Different MIME-compliant mail readers exhibit different behavior, especially when dealing with "multipart" MIME messages (i.e., documents which have been split up into multiple messages), so check your local documentation on how to manipulate these messages. For questions, please mail to Internet-Drafts@cnri.reston.va.us. Below is the data which will enable a MIME compliant mail reader implementation to automatically retrieve the ASCII version of the Internet-Draft. --NextPart Content-Type: Multipart/Alternative; Boundary="OtherAccess" --OtherAccess Content-Type: Message/External-body; access-type="mail-server"; server="mailserv@ds.internic.net" Content-Type: text/plain Content-ID: <19951010103755.I-D@CNRI.Reston.VA.US> ENCODING mime FILE /internet-drafts/draft-ietf-dnssec-secext-06.txt --OtherAccess Content-Type: Message/External-body; name="draft-ietf-dnssec-secext-06.txt"; site="ds.internic.net"; access-type="anon-ftp"; directory="internet-drafts" Content-Type: text/plain Content-ID: <19951010103755.I-D@CNRI.Reston.VA.US> --OtherAccess-- --NextPart--   Received: from relay.tis.com by neptune.TIS.COM id aa06059; 11 Oct 95 14:55 EDT Received: from sol.tis.com(192.33.112.100) by relay.tis.com via smap (g3.0.1) id xma011848; Wed, 11 Oct 95 14:38:24 -0400 Received: from polar.tis.com by tis.com (4.1/SUN-5.64) id AA14391; Wed, 11 Oct 95 14:55:12 EDT Message-Id: <9510111855.AA14391@tis.com> To: "Edie E. Gunter" Cc: dns-security@TIS.COM, jis@mit.edu, yakov@cisco.com, set@thumper.bellcore.com, randy@psg.com, ogud@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: Your message of "Tue, 10 Oct 1995 09:52:16 CDT." <9510101352.AA19385@edisto.watson.ibm.com> Date: Wed, 11 Oct 1995 14:55:01 -0400 From: Olafur Gudmundsson "Edie E. Gunter" writes: > I have a few comments on the draft... > I will take a stab at few of these comments > - Section 3 says: > > Security > aware DNS implementations MUST be designed to handle at least two > simultaneously valid keys of the same type associated with a name. > > Why isn't the ability to handle one enough? Why MUST two valid > keys be supported? Optional support of more than one is fine. > (Why would anyone want more than one KEY of the same type, anyway?) Two examples: Current Key and Future Key. Current Key and Old Key. A zone may have decided to use a new key but it can not start signing with that key untill its superzone has signed the key. Superzone will have to sign two KEY RR's for the zone during KEY transition. Zone can not start signing with the new key until the superzone has signed the new key. Superzone can not stop signing the old KEY until after the zone starts signing with the New KEY. If zone knows that zonekey has been compromized it may request the superzone to only sign the NEW KEY. This will lead to service interruptions, but this is an acceptable price to pay in this rare case. Even if zone has started to use the new KEY, a server may have two sets RR's from the zone one signed by the OLD KEY and one signed by the NEW KEY, as long as the TTL and or the Signature have not expired on the RR's signed by the OLD KEY these are valid RR's. Zone may also have Key for signing zone (640bits and with exponent=3), and a second key for MOSS (2084bits and with exponent>2^20) and a third key for IPSEC (1028bits with exponent>2^12K). > - Section 4 says: > > The SIG RR unforgably authenticates other RRs of a particular type, > class, and name and binds them to a time interval and the signer's > domain name. > > If this is true, why isn't the SIG on a dynamic update sufficient > to make that name/RR a full-fledged part of the DNS database, > allowing dynamically updated data to be treated just like "static" > data? If this is true, why do we even need the distinction of > static versus dynamic RRs? Signed static RR's are covered by the SIG(AXFR). SIG(AXFR) needs to be recalculated if there are any changes (see more below). > > - Section 4.1.3 says: > > Thus > such dynamic RRs are not directly signed by the zone, are not > included in the AXFR SIG, and are not generally protected against > omission from zone transfers. > > I am quite sure this is not what anyone running a secure DNS that > supports secure dynamic updates would want. It seems this section > should cover how to securely include dynamic updates in a zone transfer -- > if not via the method described in 4.1.3 using AXFR SIG, etc. then by > some other method. IF Dynamic RR's are covered by SIG(AXFR) then the SIG(AXFR) has to be recomputed whenever a dynamic RR changes. To do this in REAL TIME the P RIVATE zonekey has to be online and available to the primary server. See section 7.2 for more details. > - Section 4.3 says: > > Only a proper SIG RR signed by the zone can authenticate RRs. > > What about entity signed dynamic RRs? > > - Section 4.4 Signature Expiration > > When a SIG expires, the covered RR's are not removed from the database, > but are kept around and the AD bit is used to indicate if the data > is no longer authentic. Is that right? Incorrect: When the SIG expires the RR's are to be purged. > > - Section 5.1 says: > > The NXT RRs for a zone should be automatically calculated and added > to the zone by the same recommended off-line process that signs the > zone. > > What about dynamic updates? Can't you get into a situation where > something was added via a dynamic update and the NXT RR computed at > start-up is no longer correct? It seems to me that these NXT RR's > must be computed on the fly to be accurate in the face of dynamic > updates. You can ONLY add types NOT names in a zone via secure dynamic update. The zone has to sign the KEY and NS RR's for the dynamic name in order for the name to be able to add/change it's RR's, This does not outlaw dynamic subzones, (subzone is indicated by ZONE KEY). > > - Section 6 says: > > Authenticated means that the data has a valid SIG under a KEY > traceable via a chain of zero or more SIG and KEY RRs to a KEY > configured at the resolver via its boot file. > > So, if the KEY RR for a name was in the statically read master > file for the zone, then RR's added dynamically and signed with > the private part of that KEY are considered authenticated? Correct if the KEY has sign bit set and the new RR are stored under the same name as the KEY. > > - Section 6.1 says: > > Security aware servers never return Bad data. > > Is this true, given that zone transfers may omit dynamically added > RR's and given that NXT RR's are calculated offline? Perhaps I > don't understand the definition of Bad data here. RR's that fail Signature check, RR's with expired Signature RR's with expired TTL... > - Section 7.2 says: > > Periodically an application can be > run to re-sign the RRs in a zone by adding NXT and SIG RRs. > > It seems to get dynamic updates to work within the DNSSEC framework, > this period would have to be such that everything is re-signed > after each dynamic update. The update becomes part of the "static" > data and all the "static" data is then resigned. No, this can't be right. Unless data that was dynamic has been added to the zone master file the dynamic data stays dynamic. Remember the only RR's signed by a zone for a dynamic name are KEY (and possibily NS) RR's. All other RR's are signed by the private key of that name. > > - Section 7.5 says: > > It is recommended that signature lifetime be a small multiple of the > TTL but not less than a reasonable re-signing interval. > > In an environment where DHCP is used to hand out IP address leases > and DNS is updated dynamically to reflect the lease information, > the lifetime of the data will usually be that of the lease duration. > In the case of mobile clients, this lease duration may be just 5 - 10 > minutes. That said, what is your idea of a reasonable re-signing interval? for static zone a day, week, 2 weeks, month, depending on local policy and requirements. If you have a signing process that you can securly send data, you can have expiration time as short as you want. But you need to lower your TTL time to be say 1 minute. > > - Also, it was mentioned to me in private email that: > > if you want a completely dynamic zone, you can just have > the zone key sign an entity key with wildcard authority over the > entire zone and then use the entity key for everything in the zone > > I don't see anything like this discussed in the draft -- > particularly with respect to zone transfers and handling > NXT records. (And if there really is this other way to do security > in DNS servers that support dynamic updates, I'd really > like to understand how it would work!) Simple you create a subzone for dynamic hosts, when ever there is a change in the zone some online process resigns the whole zone. Seriously, this is possible, and it is possible to optimize the process to only sign the changed RR and calculate the new SIG(AXFR). > > Edie Olafur   Received: from relay.tis.com by neptune.TIS.COM id aa16053; 12 Oct 95 3:15 EDT Received: from phoenix.csie.nctu.edu.tw(140.113.17.171) by relay.tis.com via smap (g3.0.1) id xma019013; Thu, 12 Oct 95 02:55:19 -0400 Received: from liny..liny (liny.csie.nctu.edu.tw [140.113.17.105]) by phoenix.csie.nctu.edu.tw (8.6.11/8.6.4) with SMTP id PAA01491 for ; Thu, 12 Oct 1995 15:12:34 +0800 Received: by liny..liny (4.1/SMI-4.1) id AA10072; Fri, 13 Oct 95 03:11:28 CST Date: Fri, 13 Oct 95 03:11:28 CST From: lin Message-Id: <9510121911.AA10072@liny..liny> To: dns-security@TIS.COM Subject: please post The ACM/Baltzer Wireless Networks Journal announces a special issue on Personal Communications Scope: Personal communications provide communication services anywhere, anytime, with anybody, and in any form. To implement the personal communications concepts, extremely sophisticated systems which integrate many diverse technologies are required. This special focuses on the research and development of advanced PCS technologies. Original contributions related to the following topics are solicited: - Small scale mobility (handover) management - Channel allocation algorithms - Large scale mobility (roaming) management - Privacy and authentication - Multi-tier system - PCS database reliability - Intelligent networks for PCS - PCS data applications - PCS backbone architecture (e.g., ATM) - Local wireless network - Wireless multimedia - Mobile IP - Modeling of PCS (measurement, analysis, and simulation) Authors are invited to submit postscript files of their papers to liny@csie.nctu.edu.tw or submit 6 copies of their papers to Professor Yi-Bing Lin, Dept. Comp. Sci. & Info. Engr., National Chiao Tung University, Hsinchu, Taiwan, R.O.C. Papers should not exceed twenty double spaced pages in length, excluding figures and diagrams. Submission deadline: April 15, 1996 Acceptance notification: July 30, 1996 Final manuscript due: October 30, 1996 Guest editors: Yi-Bing Lin Dept. Comp. Sci. & Info. Engr. National Chiao Tung University Hsinchu, Taiwan, R.O.C. Russell T. Hsing Bellcore MRE 2M199 445 South St. Morristown, NJ 07960 trh@thumper.bellcore.com   Received: from relay.tis.com by neptune.TIS.COM id aa06402; 16 Oct 95 10:44 EDT Received: from bacchus.eng.umd.edu(129.2.94.5) by relay.tis.com via smap (g3.0.1) id xma002149; Mon, 16 Oct 95 10:26:36 -0400 Received: from gutenberg.eng.umd.edu (gutenberg.eng.umd.edu [129.2.90.102]) by bacchus.eng.umd.edu (8.7/8.7) with ESMTP id KAA13058; Mon, 16 Oct 1995 10:45:30 -0400 (EDT) From: Saroj Bhandari Received: (saroj@localhost) by gutenberg.eng.umd.edu (8.7/8.6.4) id KAA21217; Mon, 16 Oct 1995 10:45:29 -0400 (EDT) Date: Mon, 16 Oct 1995 10:45:29 -0400 (EDT) Message-Id: <199510161445.KAA21217@gutenberg.eng.umd.edu> To: dns-security@TIS.COM Subject: call for papers Cc: tony@eng.umd.edu Call for Papers Hybrid and Satellite Communication Networks A special issue to be published in WIRELESS NETWORKS published in cooperation with the ACM: Scope: As attention is focused today on wireless communications, a key component of the wireless connectivity fabric is often overlooked. Satellites represent a crucial element of the global information infrastructure and are experiencing a quiet technology revolution that will multiply their capabilities significantly. The recent launches of OLYMPUS in Europe and the ACTS in the United States have proven that on-board processing, bandwidth-on-demand, switchable spot-beams, and the use of the Ka-band can convert, until now, the passive "bent-pipe" reflectors to powerful, full-fledged network nodes. The satellite advantages of ubiquitous coverage, easy access, large bandwidth, immunity to terrestrial catastrophes, and relatively low-cost add up to make satellites indispensable as parts of the worldwide information highway. The much discussed personal communication systems that are currently under development, from Motorola's Iridium to the Teledesics bold constellation concept, demonstrate one aspect of the envisioned role of future satellite systems in the mobile communication area. The main technical bottlenecks that must be overcome to permit the seamless incorporation of satellites into modern hybrid networks and their transparent interoperability with terrestrial links (whether wireless or not) include: - The mismatch of bandwidth, error-rate, and propagation delay properties between satellite and terrestrial links. - The need for seamless network protocol operation - The differences among the multiple services anticipated by such networks in the emerging multimedia markets - The congestion, access, admission control, and bandwidth allocation problems - The cost of terminal manufacturing with dual (space/terrestrial) capabilities - The regulatory, standardization, pricing, and other commercial and business issues that impact the operation of such systems. Authors are invited to send 6 copies of their papers to the guest editor on subjects that relate to the above topics. Please list contact persons, addresses, phone, fax, and e-mail information on the front page of the paper. The following schedule will be followed: Manuscript submission: February 15, 1996 Acceptance notification: June 15, 1996 Final Manuscript Due: September 15, 1996 Publication Date: 4th quarter 1997 Guest Editor: Anthony Ephremides Dept. of Electrical Engineering University of Maryland College Park, MD 20742, USA   Received: from relay.tis.com by neptune.TIS.COM id aa07004; 16 Oct 95 11:12 EDT Received: from watson.ibm.com(129.34.139.4) by relay.tis.com via smap (g3.0.1) id xma002804; Mon, 16 Oct 95 10:54:36 -0400 Received: from WATSON by watson.ibm.com (IBM VM SMTP V2R3) with BSMTP id 4367; Mon, 16 Oct 95 11:13:10 EDT Received: from YKTVMV by watson.vnet.ibm.com with "VAGENT.V1.02 on VAGENT2" id 6249; Mon, 16 Oct 1995 11:13:10 EDT Received: from edisto.watson.ibm.com by yktvmv.watson.ibm.com (IBM VM SMTP V2Rx) with TCP; Mon, 16 Oct 95 11:13:09 EDT Received: by edisto.watson.ibm.com (AIX 3.2/UCB 5.64/900524) id AA17610; Mon, 16 Oct 1995 11:12:52 -0400 Message-Id: <9510161512.AA17610@edisto.watson.ibm.com> X-External-Networks: yes To: dns-security@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: Your message of Wed, 11 Oct 95 14:55:01 D. <9510111855.AA14391@tis.com> Date: Mon, 16 Oct 95 11:12:51 -0500 From: "Edie E. Gunter" When a SIG RR expires, is the SIG RR itself removed from the database? It seems to be understood that the covered RR's are removed, though I don't see this in the spec. My question is about the SIG RR itself. If the SIG RR is kept around, what TTL value is used when this expired SIG RR is being put into a query response? The computation in section 4.4 might lead one to think a negative TTL value is used, since sigExpTime is now in the past. Edie   Received: from relay.tis.com by neptune.TIS.COM id aa09006; 16 Oct 95 12:44 EDT Received: from sol.tis.com(192.33.112.100) by relay.tis.com via smap (g3.0.1) id xma004526; Mon, 16 Oct 95 12:26:46 -0400 Received: from polar.tis.com.tis.com by tis.com (4.1/SUN-5.64) id AA07976; Mon, 16 Oct 95 12:44:09 EDT Date: Mon, 16 Oct 95 12:44:09 EDT From: Olafur Gudmundsson Message-Id: <9510161644.AA07976@tis.com> Received: by polar.tis.com.tis.com (4.1/SMI-4.1) id AA09257; Mon, 16 Oct 95 12:43:58 EDT To: dns-security@TIS.COM Subject: ANNOUNCEMENT: TIS/DNSSEC Version 1.3 alpha A new version of TIS/DNSSEC (alpha1.3) is now available. This version is distinguished from the previous version as follows. Supports AXFR to great extent SIG(AXFR) fails in most cases, due to incorrect transmission order of names. Change in resolver.conf to specify what nameservers to trust although this information is not used yet. First draft of man pages (comments please please) What is implemented is in sync with latest dns-sec draft (06) Number of small improvements and bug fixes, see /pub/DNSSEC/CHANGES What is missing from the current implementation Signature verification in resolver Automatic return of KEY RR with NS and Address RR's. Purging of expired SIGNATURES and RR's. Proper handling of SIG(AXFR) Transaction Signatures. (we are not going to implement this) For information on how to acquire TIS/DNSSEC retrieve the file /pub/DNSSEC/README on the host ftp.tis.com via anonymous FTP. If you have any questions or problems please send a note to tisdnssec-support@tis.com. Enjoy, Olafur   Received: from relay.tis.com by neptune.TIS.COM id aa27455; 17 Oct 95 9:42 EDT Received: from sol.tis.com(192.33.112.100) by relay.tis.com via smap (g3.0.1) id xma017240; Tue, 17 Oct 95 09:23:56 -0400 Received: from polar.tis.com by tis.com (4.1/SUN-5.64) id AA28555; Tue, 17 Oct 95 09:41:28 EDT Message-Id: <9510171341.AA28555@tis.com> To: "Edie E. Gunter" Cc: dns-security@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: Your message of "Mon, 16 Oct 1995 11:12:51 CDT." <9510161512.AA17610@edisto.watson.ibm.com> Date: Tue, 17 Oct 1995 09:41:16 -0400 From: Olafur Gudmundsson "Edie E. Gunter" writes: > > When a SIG RR expires, is the SIG RR itself removed from > the database? It seems to be understood that the covered > RR's are removed, though I don't see this in the spec. My > question is about the SIG RR itself. Yes it also expires when it's expiration time arrives. There is no other logical answer. > > If the SIG RR is kept around, what TTL value is used when > this expired SIG RR is being put into a query response? > The computation in section 4.4 might lead one to think > a negative TTL value is used, since sigExpTime is now in > the past. No no no, when the expiration time arrives RR's and SIG are out of date and can not be returned in an answer. Olafur > > Edie   Received: from relay.tis.com by neptune.TIS.COM id aa04052; 17 Oct 95 13:22 EDT Received: from watson.ibm.com(129.34.139.4) by relay.tis.com via smap (g3.0.1) id xma021648; Tue, 17 Oct 95 13:04:33 -0400 Received: from WATSON by watson.ibm.com (IBM VM SMTP V2R3) with BSMTP id 7175; Tue, 17 Oct 95 13:23:18 EDT Received: from YKTVMV by watson.vnet.ibm.com with "VAGENT.V1.02 on VAGENT2" id 7966; Tue, 17 Oct 1995 13:23:18 EDT Received: from edisto.watson.ibm.com by yktvmv.watson.ibm.com (IBM VM SMTP V2Rx) with TCP; Tue, 17 Oct 95 13:23:18 EDT Received: by edisto.watson.ibm.com (AIX 3.2/UCB 5.64/900524) id AA15002; Tue, 17 Oct 1995 13:23:01 -0400 Message-Id: <9510171723.AA15002@edisto.watson.ibm.com> X-External-Networks: yes To: dns-security@TIS.COM Cc: jis@mit.edu, yakov@cisco.com, set@thumper.bellcore.com, randy@psg.com, ogud@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: Your message of Wed, 11 Oct 95 14:55:01 D. <9510111855.AA14391@tis.com> Date: Tue, 17 Oct 95 13:23:01 -0500 From: "Edie E. Gunter" >> > >> > - Section 4.1.3 says: >> > >> > Thus >> > such dynamic RRs are not directly signed by the zone, are not >> > included in the AXFR SIG, and are not generally protected against >> > omission from zone transfers. >> > >> > I am quite sure this is not what anyone running a secure DNS that >> > supports secure dynamic updates would want. It seems this section >> > should cover how to securely include dynamic updates in a zone transfer -- >> > if not via the method described in 4.1.3 using AXFR SIG, etc. then by >> > some other method. >> IF Dynamic RR's are covered by SIG(AXFR) then the SIG(AXFR) has to be >> recomputed whenever a dynamic RR changes. This would seem to be a much more desirable behavior than not covering the dynamic RRs and allowing them to be omitted in zone transfers. >> > - Section 4.4 Signature Expiration >> > >> > When a SIG expires, the covered RR's are not removed from the database, >> > but are kept around and the AD bit is used to indicate if the data >> > is no longer authentic. Is that right? >> Incorrect: When the SIG expires the RR's are to be purged. Can anyone cite the chapter/verse in the spec where this is covered? >> > >> > - Section 5.1 says: >> > >> > The NXT RRs for a zone should be automatically calculated and added >> > to the zone by the same recommended off-line process that signs the >> > zone. >> > >> > What about dynamic updates? Can't you get into a situation where >> > something was added via a dynamic update and the NXT RR computed at >> > start-up is no longer correct? It seems to me that these NXT RR's >> > must be computed on the fly to be accurate in the face of dynamic >> > updates. >> You can ONLY add types NOT names in a zone via secure dynamic update. >> The zone has to sign the KEY and NS RR's for the dynamic name in order for >> the name to be able to add/change it's RR's, If the static database contains the name APPLE and a KEY RR for that name, then an NXT RR will be computed indicating that APPLE has no A RR. If the A RR is later dyamically added, then the NXT RR computed earlier is no longer correct. The NXT RR must be recomputed after the dynamic update. >> > >> > - Also, it was mentioned to me in private email that: >> > >> > if you want a completely dynamic zone, you can just have >> > the zone key sign an entity key with wildcard authority over the >> > entire zone and then use the entity key for everything in the zone >> > >> > I don't see anything like this discussed in the draft -- >> > particularly with respect to zone transfers and handling >> > NXT records. (And if there really is this other way to do security >> > in DNS servers that support dynamic updates, I'd really >> > like to understand how it would work!) >> Simple you create a subzone for dynamic hosts, >> when ever there is a change in the zone some online process resigns the whole zone. >> Seriously, this is possible, and it is possible to optimize the process to only >> sign the changed RR and calculate the new SIG(AXFR). I don't see how this makes sense in practice. I've got a domain, watson.ibm.com. I want all the watson users to be in that domain. It seems odd to me to impose STATIC.watson.ibm.com and DYNAMIC.watson.ibm.com domains on the users. But, if static and dynamic RRs are allowed in the same zone, and if the SIG(AXFR) only covers the static RRs, then when a zone transfer is done, say to a secondary, how will that secondary know which RRs are static and which are dynamic so that is can verify the data? It must be implied that there is some new tag on the RR somewhere to indicate if the RR was added dynamically. Otherwise, the secondary is just going to recompute/verify the SIG using _all_ the RRs. No? (I suppose the secondary could go through the database and verify each and every individual SIG and thereby determine which were signed by the zone and which were not and use that to determine which RRs to include in the SIG(AXFR) verification...) Does anyone know if the TIS dnssec implementation supports dynamic updates? Edie   Received: from relay.tis.com by neptune.TIS.COM id aa16388; 23 Oct 95 8:46 EDT Received: from sol.tis.com(192.33.112.100) by relay.tis.com via smap (g3.0.1) id xma003624; Mon, 23 Oct 95 08:27:30 -0400 Received: from antares.tis.com by tis.com (4.1/SUN-5.64) id AA28028; Mon, 23 Oct 95 08:45:29 EDT Message-Id: <9510231245.AA28028@tis.com> Reply-To: James M Galvin To: dns-security@TIS.COM Subject: meeting in Dallas Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Id: <11690.814452419.1@tis.com> Date: Mon, 23 Oct 1995 08:47:00 -0400 From: James M Galvin Please note we have a meeting slot reserved for 9am, tuesday, December 5, in Dallas. We'll have document status, implementation status, and dynamic update to discuss. There may be other topics; we'll know for sure as the meeting approaches. Jim   Received: from relay.tis.com by neptune.TIS.COM id aa21798; 25 Oct 95 1:14 EDT Received: from fawlty1.eng.monash.edu.au(130.194.140.11) by relay.tis.com via smap (g3.0.1) id xma003241; Wed, 25 Oct 95 00:53:18 -0400 Received: (atiq@localhost) by fawlty1.eng.monash.edu.au (8.6.12/8.6.4) id PAA15804 for dns-security@tis.com; Wed, 25 Oct 1995 15:13:16 +1000 Message-Id: <199510250513.PAA15804@fawlty1.eng.monash.edu.au> Subject: CFP: Special issue on ATM Switching To: dns-security@TIS.COM Date: Wed, 25 Oct 1995 15:13:10 +1000 (EST) Reply-to: Mohammed Atiquzzaman From: Mohammed Atiquzzaman X-Mailer: ELM [version 2.4 PL21] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 3297 Call for Papers Special Issue of International Journal of Computer Systems Science & Engineering on ATM Switching Guest Editors: Hussein T. Mouftah, Queen's University, Canada Mohammed Atiquzzaman, Monash University, Australia. _______________________________________________________________________________ Papers are solicited for a special issue of the International Journal of Computer Systems Science & Engineering on Asynchronous Transfer Mode (ATM) Switching to be published in the third quarter of 1996. During the past decade, a considerable amount of effort has been made in studying and designing ATM switches which is believed to be the most developed aspect of ATM. The field has now become a mature area and ATM switches are becoming commercially available. This special issue will include a set of original and survey articles from both industry and academia that represents the current state-of-the-art in ATM switching. Possible topics include (but are not limited to): o Switch architectures o Fault tolerance o Buffering schemes o Congestion control and traffic management o Performance modeling o Practical experience & field trials o Buffer management o Simulation techniques for large switches o Commercial switches Five copies of complete manuscripts (not to exceed 25 double-spaced pages) should be sent to Mohammed Atiquzzaman by 1 February 1996. Please include a title page containing author(s) names and affiliations, postal addresses, e-mail addresses, telephone numbers, and fax numbers. Electronic (PostScript only) submissions are encouraged. Authors should follow the IJCSSE manuscript submission format. _______________________________________________________________________________ Guest Editors: _______________________________________________________________________________ Mohammed Atiquzzaman Hussein T. Mouftah Dept. of Elect. & Comp. Systems Engg. Department of Elect. & Comp. Engg. Monash University, Clayton 3168 Queen's University, Kingston Melbourne, Australia. Ontario, Canada K7L 3N6. Tel: +61 3 9905 5383 Tel: +1 613-545-2934 Fax: +61 3 9905 3454 Fax: +1 613-545-6615 Email: atiq@eng.monash.edu.au Email: mouftah@eleceng.ee.queensu.ca WWW: http://www.eng.monash.edu.au/~atiq _______________________________________________________________________________ Important Dates: _______________________________________________________________________________ Deadline for receipt of manuscripts: 1 February 1996 Notification of acceptance/rejection: 30 April 1996 ASCII and PostScript versions of this announcement and the author's guidelines for IJCSSE are available from http://www.eng.monash.edu.au/~atiq IJCSSE is published by CRL Publishing, London, UK. Please contact the editor-in-chief Prof. Tharam Dillon (tharam@latcs1.lat.oz.au) for queries regarding the journal and J. Thompson (100113.2636@CompuServe.com) for sample copies.   Received: from relay.tis.com by neptune.TIS.COM id aa13528; 10 Nov 95 11:49 EST Received: from gw2.att.com(192.20.239.134) by relay.tis.com via smap (g3.0.1) id xma011377; Fri, 10 Nov 95 11:27:01 -0500 Received: from elmo.lz.att.com by ig1.att.att.com id AA29266; Wed, 8 Nov 95 17:56:36 EST Received: from fireball.att.com by elmo.lz.att.com (5.x/SMI-SVR4) id AA13803; Wed, 8 Nov 1995 17:57:51 -0500 Received: by fireball.att.com (5.x/SMI-SVR4) id AA19620; Wed, 8 Nov 1995 17:56:32 -0500 Date: Wed, 8 Nov 1995 17:56:32 -0500 Message-Id: <9511082256.AA19620@fireball.att.com> From: dnssec@fireball.lz.att.com To: dns-security@TIS.COM Subject: A Simple Question I've read (most of) draft-ietf-dnssec-secext-05.txt and have either missed something, or have failed to comprehend something. I don't know if this is the right place to ask such a simple question, but here goes: So I'm a security aware resolver and I query for, say, Type A records on name A.B.C.D. I get back an A record and a SIG record: A.B.C.D IN A [some ttl] 135.24.40.12 A.B.C.D IN SIG [some ttl] [Type A SIG RDATA] How do I figure out which public KEY I'm supposed to use to authenticate the A record? If the answer to my question is something like, ``Use a KEY associated with the SIGNER'S NAME (a field in A.B.C.D's Type A SIG record),'' then how do I know that the signer is at all appropriate. For example, it would seem inappropriate to consider the A record authentic, if the SIG was generated by W.X.Y.Z (some unknown entity from another zone), even if the MD5/RSA stuff all checks out. Assuming my question is clearly addressed somewhere in the draft, then perhaps someone could just tell me which section I should read more carefully. Thanks, _________________ Matt Busche AT&T Bell Laboratories e-mail: dnssec@fireball.lz.att.com 307 Middletown-Lincroft Road Voice: 908-576-3630 Room 1E-124 FAX: 908-576-5007 Lincroft, NJ 07738-1526   Received: from relay.tis.com by neptune.TIS.COM id aa15541; 10 Nov 95 13:44 EST Received: from watson.ibm.com(129.34.139.4) by relay.tis.com via smap (g3.0.1) id xma013088; Fri, 10 Nov 95 13:23:06 -0500 Received: from WATSON by watson.ibm.com (IBM VM SMTP V2R3) with BSMTP id 8801; Fri, 10 Nov 95 13:45:17 EST Received: from YKTVMV by watson.vnet.ibm.com with "VAGENT.V1.02 on VAGENT2" id 7560; Fri, 10 Nov 1995 13:45:17 EST Received: from edisto.watson.ibm.com by yktvmv.watson.ibm.com (IBM VM SMTP V2Rx) with TCP; Fri, 10 Nov 95 13:45:16 EST Received: by edisto.watson.ibm.com (AIX 3.2/UCB 5.64/900524) id AA18042; Fri, 10 Nov 1995 13:45:01 -0500 Message-Id: <9511101845.AA18042@edisto.watson.ibm.com> X-External-Networks: yes To: dnssec@fireball.lz.att.com, dns-security@TIS.COM Subject: Re: A Simple Question In-Reply-To: Your message of Wed, 08 Nov 95 17:56:32 EST. <9511082256.AA19620@fireball.att.com> Date: Fri, 10 Nov 95 13:45:00 -0500 From: "Edie E. Gunter" > So I'm a security aware resolver and I query for, say, Type A records > on name A.B.C.D. I get back an A record and a SIG record: > > A.B.C.D IN A [some ttl] 135.24.40.12 > A.B.C.D IN SIG [some ttl] [Type A SIG RDATA] > > How do I figure out which public KEY I'm supposed to use to > authenticate the A record? The RR's for A.B.C.D can be signed by the entity A.B.C.D and/or the zone. So, if you don't have the public key for A.B.C.D and/or the zone, you'll have to query the server for those KEY RR's also (perhaps using transaction SIGs if you're really paranoid.) Now, there can be multiple keys per name. (i.e. A.B.C.D may have multiple KEY RRs for the same algorithm type.) The best explanation I've heard for handling this is to just try them all and see if any work... All KEY RR's are signed by the zone. W.X.Y.Z can't generate a SIG for A.B.C.D unless it knows either the private key for A.B.C.D or the private key for the zone (and you're allowing dynamic updates.) W.X.Y.Z should never know another name's private key. Once the private key is exposed, you're no longer secure. Edie   Received: from relay.tis.com by neptune.TIS.COM id aa26419; 13 Nov 95 5:26 EST Received: from oden.exmandato.se(192.71.33.1) by relay.tis.com via smap (g3.0.1) id xma029351; Mon, 13 Nov 95 05:04:54 -0500 Received: from li50.exmandato.se (ex125.exmandato.se [192.71.33.125]) by oden.exmandato.se (8.6.12/8.6.12) with SMTP id LAA27498; Mon, 13 Nov 1995 11:44:11 +0100 Date: Mon, 13 Nov 1995 11:44:11 +0100 Message-Id: <199511131044.LAA27498@oden.exmandato.se> X-Sender: mats@exmandato.se X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: Olafur Gudmundsson , dns-security@TIS.COM From: Mats Mellstrand Subject: Re: ANNOUNCEMENT: TIS/DNSSEC Version 1.3 alpha At 12:44 1995-10-16 EDT, Olafur Gudmundsson wrote: >A new version of TIS/DNSSEC (alpha1.3) is now available. This version is >distinguished from the previous version as follows. > > Supports AXFR to great extent SIG(AXFR) fails in most cases, > due to incorrect transmission order of names. > Change in resolver.conf to specify what nameservers to trust > although this information is not used yet. > First draft of man pages (comments please please) > What is implemented is in sync with latest dns-sec draft (06) > Number of small improvements and bug fixes, see /pub/DNSSEC/CHANGES > >What is missing from the current implementation > Signature verification in resolver > Automatic return of KEY RR with NS and Address RR's. > Purging of expired SIGNATURES and RR's. > Proper handling of SIG(AXFR) > Transaction Signatures. (we are not going to implement this) > >For information on how to acquire TIS/DNSSEC retrieve the file >/pub/DNSSEC/README on the host ftp.tis.com via anonymous FTP. > >If you have any questions or problems please send a note to >tisdnssec-support@tis.com. > >Enjoy, > >Olafur > > -------------------------------------------------------------------------- Mats Mellstrand, eXmandato AB, Box 251, 391 23 Kalmar, Sweden Tel (int):46-48012260, fax (int):46-48012280 mats@exmandato.se, http://www.exmandato.se   Received: from relay.tis.com by neptune.TIS.COM id aa26418; 13 Nov 95 5:26 EST Received: from oden.exmandato.se(192.71.33.1) by relay.tis.com via smap (g3.0.1) id xma029350; Mon, 13 Nov 95 05:04:47 -0500 Received: from li50.exmandato.se (ex125.exmandato.se [192.71.33.125]) by oden.exmandato.se (8.6.12/8.6.12) with SMTP id LAA27494; Mon, 13 Nov 1995 11:44:01 +0100 Date: Mon, 13 Nov 1995 11:44:01 +0100 Message-Id: <199511131044.LAA27494@oden.exmandato.se> X-Sender: mats@exmandato.se X-Mailer: Windows Eudora Pro Version 2.1.2 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: Olafur Gudmundsson , dns-security@TIS.COM From: Mats Mellstrand Subject: Re: ANNOUNCEMENT: TIS/DNSSEC Version 1.3 alpha At 12:44 1995-10-16 EDT, Olafur Gudmundsson wrote: >A new version of TIS/DNSSEC (alpha1.3) is now available. This version is >distinguished from the previous version as follows. > > Supports AXFR to great extent SIG(AXFR) fails in most cases, > due to incorrect transmission order of names. > Change in resolver.conf to specify what nameservers to trust > although this information is not used yet. > First draft of man pages (comments please please) > What is implemented is in sync with latest dns-sec draft (06) > Number of small improvements and bug fixes, see /pub/DNSSEC/CHANGES > >What is missing from the current implementation > Signature verification in resolver > Automatic return of KEY RR with NS and Address RR's. > Purging of expired SIGNATURES and RR's. > Proper handling of SIG(AXFR) > Transaction Signatures. (we are not going to implement this) > >For information on how to acquire TIS/DNSSEC retrieve the file >/pub/DNSSEC/README on the host ftp.tis.com via anonymous FTP. > >If you have any questions or problems please send a note to >tisdnssec-support@tis.com. > >Enjoy, > >Olafur > > -------------------------------------------------------------------------- Mats Mellstrand, eXmandato AB, Box 251, 391 23 Kalmar, Sweden Tel (int):46-48012260, fax (int):46-48012280 mats@exmandato.se, http://www.exmandato.se   Received: from relay.tis.com by neptune.TIS.COM id aa29946; 14 Nov 95 16:59 EST Received: from watson.ibm.com(129.34.139.4) by relay.tis.com via smap (g3.0.1) id xma028203; Tue, 14 Nov 95 16:38:16 -0500 Received: from WATSON by watson.ibm.com (IBM VM SMTP V2R3) with BSMTP id 7837; Tue, 14 Nov 95 16:59:23 EST Received: from YKTVMV by watson.vnet.ibm.com with "VAGENT.V1.02 on VAGENT2" id 9992; Tue, 14 Nov 1995 16:59:23 EST Received: from edisto.watson.ibm.com by yktvmv.watson.ibm.com (IBM VM SMTP V2Rx) with TCP; Tue, 14 Nov 95 16:59:22 EST Received: by edisto.watson.ibm.com (AIX 3.2/UCB 5.64/900524) id AA18904; Tue, 14 Nov 1995 16:59:10 -0500 Message-Id: <9511142159.AA18904@edisto.watson.ibm.com> X-External-Networks: yes To: dns-security@TIS.COM Subject: NSCOUNT Date: Tue, 14 Nov 95 16:59:09 -0500 From: "Edie E. Gunter" The DNSSEC draft seems to suggest that if DNS returns an NS RR in the authority section of a query response, then the SIG should also be included in the authority section of the response. Is this correct? If so, then it seems that in order for the message to be parsed correctly, the NSCOUNT field would have to be set to 2 instead of 1, to account for the SIG and the NS RR. But, the NSCOUNT field is defined (RFC 883, 1035 and elsewhere) to be the number of NS RRs in the authority section. So, it seems that the DNSSEC draft is redefining the meaning of the NSCOUNT field, though I don't see this mentioned explicitly. If the above is true, then is there is problem working with older non-security-aware servers? Are they going to fail when they get a response with an nscount of 2 but only 1 actual NS RR? Edie   Received: from relay.tis.com by neptune.TIS.COM id aa06585; 15 Nov 95 0:13 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma002532; Tue, 14 Nov 95 23:51:45 -0500 Received: by callandor.cybercash.com; id AAA29300; Wed, 15 Nov 1995 00:14:47 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma029297; Wed, 15 Nov 95 00:14:40 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA12039; Wed, 15 Nov 95 00:13:07 EST Date: Wed, 15 Nov 1995 00:13:06 -0500 (EST) From: "Donald E. Eastlake 3rd" To: "Edie E. Gunter" Cc: dns-security@TIS.COM Subject: Re: NSCOUNT In-Reply-To: <9511142159.AA18904@edisto.watson.ibm.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Edie, On Tue, 14 Nov 1995, Edie E. Gunter wrote: > The DNSSEC draft seems to suggest that if DNS returns an NS > RR in the authority section of a query response, then the > SIG should also be included in the authority section of the > response. Is this correct? Yes, the idea being that you wouldn't want additional info to cause loss of the AIG authentication the authority info (or authority info to cause loss of the SIG for the main response) due to truncation. > If so, then it seems that in order for the message to be > parsed correctly, the NSCOUNT field would have to be set to > 2 instead of 1, to account for the SIG and the NS RR. Or possibly more for multiple SIGs. Also, the NXT RR authenticating the non-existence of a name appears in the authority section. > But, the NSCOUNT field is defined (RFC 883, 1035 and elsewhere) > to be the number of NS RRs in the authority section. > So, it seems that the DNSSEC draft is redefining the > meaning of the NSCOUNT field, though I don't see this > mentioned explicitly. You are correction and I guess this should be added to the draft. > If the above is true, then is there is problem working > with older non-security-aware servers? Are they going > to fail when they get a response with an nscount of 2 > but only 1 actual NS RR? Paul Vixie has been consulted on most of these decisions. My understanding from what he has said is that older versions of BIND are quite insensitive as to what section RRs are returned in and should not have problems in these cases. > Edie Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa06862; 15 Nov 95 0:31 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma002651; Wed, 15 Nov 95 00:10:15 -0500 Received: by callandor.cybercash.com; id AAA29395; Wed, 15 Nov 1995 00:33:17 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma029393; Wed, 15 Nov 95 00:33:08 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA12149; Wed, 15 Nov 95 00:31:34 EST Date: Wed, 15 Nov 1995 00:31:32 -0500 (EST) From: "Donald E. Eastlake 3rd" To: "Edie E. Gunter" Cc: dns-security@TIS.COM, jis@mit.edu, yakov@cisco.com, set@thumper.bellcore.com Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: <9510171723.AA15002@edisto.watson.ibm.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sorry I've been distracted for a while by other things. Let me try to answer some of these messages... On Tue, 17 Oct 1995, Edie E. Gunter wrote: > >> > > >> > - Section 4.1.3 says: > >> > > >> > Thus > >> > such dynamic RRs are not directly signed by the zone, are not > >> > included in the AXFR SIG, and are not generally protected against > >> > omission from zone transfers. > >> > > >> > I am quite sure this is not what anyone running a secure DNS that > >> > supports secure dynamic updates would want. It seems this section > >> > should cover how to securely include dynamic updates in a zone transfer -- > >> > if not via the method described in 4.1.3 using AXFR SIG, etc. then by > >> > some other method. > >> IF Dynamic RR's are covered by SIG(AXFR) then the SIG(AXFR) has to be > >> recomputed whenever a dynamic RR changes. > > This would seem to be a much more desirable behavior than not > covering the dynamic RRs and allowing them to be omitted in > zone transfers. Edie, you have to understand that the DNSSEC document is not the Dynamic Update document. The DNSSEC document strives for maximum security with enough hooks to allow Dynamic Update. You get the most security by keeping the fixed master file off line, signing it off line, and having a one way flow of information to the primary DNS server for the zone. You are asking exactly how to implement both security and dyanmic update and I guess that should be answered by the Dynamic Update document security section which I should perhaps write something for/about. If the zone owner is content to trust a machine on line to the net, they could put the zone private key on line and resign the AXFR every update. This is not a speedly operation and might cause problems if the update rate is high. On the other hand, if they really trust this on line machine, then they should not fear that it would omit RRs from a zone transfer anyway. I would think the prefered implementation would be to have a fixed master file off line and a dynamic master file of dynamically added/changed RRs on-line. If you are willing to take the extra risk of putting the zone file on line and willing to sustain the extra computation of re-calculating the AXFR, then you can get the advantage of securiing the entirety of zone transfers no matter how many intermediate machines the zone has been transfered through. > >> > - Section 4.4 Signature Expiration > >> > > >> > When a SIG expires, the covered RR's are not removed from the database, > >> > but are kept around and the AD bit is used to indicate if the data > >> > is no longer authentic. Is that right? > >> Incorrect: When the SIG expires the RR's are to be purged. > > Can anyone cite the chapter/verse in the spec where this is covered? If a DNS server is security ignorant, it obviously does nothing when a SIG expires. If it's security aware, it shouldn't send out an RR whose SIG has expired and if it was caching it should purge them. It's not quite so clear to me if it was not cahcing but a primary or secondary server and I don't think it matters much. You clearly have a problem of not having re-signed and reloaded the zone soon enough. I don't think this case is covered in the current draft. It does not seem to matter much to me if the RR is purged or just keep around and not provided in answers (except in a zone transfer so the AXFR is right (except that it would probably be the case that if one zone signed SIG has expired, they all have, and you are totally out of it)). > >> > - Section 5.1 says: > >> > > >> > The NXT RRs for a zone should be automatically calculated and added > >> > to the zone by the same recommended off-line process that signs the > >> > zone. > >> > > >> > What about dynamic updates? Can't you get into a situation where > >> > something was added via a dynamic update and the NXT RR computed at > >> > start-up is no longer correct? It seems to me that these NXT RR's > >> > must be computed on the fly to be accurate in the face of dynamic > >> > updates. > >> You can ONLY add types NOT names in a zone via secure dynamic update. > >> The zone has to sign the KEY and NS RR's for the dynamic name in order for > >> the name to be able to add/change it's RR's, > > If the static database contains the name APPLE and a KEY RR for that > name, then an NXT RR will be computed indicating that APPLE has no > A RR. If the A RR is later dyamically added, then the NXT RR computed > earlier is no longer correct. The NXT RR must be recomputed after > the dynamic update. That's a very good point. I will change the draft to make it clear that the NXT type bits only cover zone signed types. Dynamically added types don't appear in NXTs unless the user has chosen the not-security-recommended keeping of their private key on line and has some DNS server implementation that will adjust and resign the NXT RRs... > >> > - Also, it was mentioned to me in private email that: > >> > > >> > if you want a completely dynamic zone, you can just have > >> > the zone key sign an entity key with wildcard authority over the > >> > entire zone and then use the entity key for everything in the zone > >> > > >> > I don't see anything like this discussed in the draft -- > >> > particularly with respect to zone transfers and handling > >> > NXT records. (And if there really is this other way to do security > >> > in DNS servers that support dynamic updates, I'd really > >> > like to understand how it would work!) > >> Simple you create a subzone for dynamic hosts, > >> when ever there is a change in the zone some online process resigns the whole zone. > >> Seriously, this is possible, and it is possible to optimize the process to only > >> sign the changed RR and calculate the new SIG(AXFR). > > I don't see how this makes sense in practice. I've got a domain, > watson.ibm.com. I want all the watson users to be in that domain. > It seems odd to me to impose STATIC.watson.ibm.com and > DYNAMIC.watson.ibm.com domains on the users. > > But, if static and dynamic RRs are allowed in the same zone, and > if the SIG(AXFR) only covers the static RRs, then when a zone > transfer is done, say to a secondary, how will that secondary > know which RRs are static and which are dynamic so that is can > verify the data? It must be implied that there is some new tag > on the RR somewhere to indicate if the RR was added dynamically. > Otherwise, the secondary is just going to recompute/verify the SIG > using _all_ the RRs. No? (I suppose the secondary could go > through the database and verify each and every individual SIG and > thereby determine which were signed by the zone and which were not > and use that to determine which RRs to include in the SIG(AXFR) > verification...) > > Does anyone know if the TIS dnssec implementation supports dynamic > updates? There are several things here. When a zone trasnfer is done in a world with dynamic update (which is *not* included in any DNSSEC implementation I know of), the secondary needs to caclulate the AXFR only over zone signed RRs, as you suggest. For dyanmically added RRs, it has to check the SIG that authorized it which should be traceable back to the zone key. Dyamic update can never change what names exist in a zone or, as pointed out above, the zone signed types. I suppose the minimum secure dynamic zone, say zone.tld, would have only four RRs: a dynamic update KEY RR, a NXT RR, and zone SIGs on them. They would have name *.zone.tld so they would cause all possible names to "exist" in the zone and the KEY would be authorized to create any name inferior to zone.tld. You would probably make the NS RRs hard also but they could in principle be dynamic (which would require a dynamic uypdate KEY with name zone.tld). Since a KEY can only authorize doing things with RRs that have its name or are within its name scope if it is a wildcard, the "existant names" structure of the zone can't change. I would think that most zone adminstrators would have static parts of their zones and dynamic parts. They might or might not want to use sub-zones but they certainly would not want to be forced to lose the added security they could get by keeping the static part off-line. There is no reason to have a fixed.watson.ibm.com but it names sense to have dynamic-authority1.watson.ibm.com, dynamic-authority2..., etc. why dyanmic stuff hapeens at and/or under the authorities. although in the limit you just have a bunch of names.watson.ibm.com with each of the names having a dynamic update KEY.. > Edie Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa07045; 15 Nov 95 0:43 EST Received: from rip.psg.com(147.28.0.39) by relay.tis.com via smap (g3.0.1) id xma002740; Wed, 15 Nov 95 00:21:34 -0500 Received: by rip.psg.com (Smail3.1.29.1 #1) id m0tFaca-00031sC; Tue, 14 Nov 95 21:42 PST Message-Id: Date: Tue, 14 Nov 95 21:42 PST From: Randy Bush To: "Donald E. Eastlake 3rd" Cc: namedroppers , dns-security@TIS.COM Subject: Re: NSCOUNT References: <9511142159.AA18904@edisto.watson.ibm.com> >> If the above is true, then is there is problem working >> with older non-security-aware servers? Are they going >> to fail when they get a response with an nscount of 2 >> but only 1 actual NS RR? > Paul Vixie has been consulted on most of these decisions. My understanding > from what he has said is that older versions of BIND are quite insensitive > as to what section RRs are returned in and should not have problems in > these cases. That's nice. But I thought we were talking about standards, not some implementation. There are other implementations. randy   Received: from relay.tis.com by neptune.TIS.COM id aa07369; 15 Nov 95 1:01 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma002805; Wed, 15 Nov 95 00:39:45 -0500 Received: by callandor.cybercash.com; id BAA29567; Wed, 15 Nov 1995 01:02:47 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma029565; Wed, 15 Nov 95 01:02:42 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA12347; Wed, 15 Nov 95 01:01:04 EST Date: Wed, 15 Nov 1995 01:01:03 -0500 (EST) From: "Donald E. Eastlake 3rd" To: Randy Bush Cc: namedroppers , dns-security@TIS.COM Subject: Re: NSCOUNT In-Reply-To: Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII At least for namedroppers, this is out of context. The DNS security draft calls for the inclusion of SIG RRs in the same section (authority, additional info, whatever) of the response as the data being signed. This is based on the assumption that in a secure DNS world, it is better to get less data, but have it authenticated, than more data but have it not authenticated (in the face of truncation). The rest of the email query and response discussed this and I agreed that the DNS security draft should explicitly say that the NSCOUNT field's meaning is modified from the current DNS standard RFC's to say that there may be non NS records (for example, SIGs) included in that section and count. Since the original query also asked, in one section, as below, about backward compatibility, I answered with what data I had on the subject. If people have other inputs in this area, I'm interested. Donald On Tue, 14 Nov 1995, Randy Bush wrote: > >> If the above is true, then is there is problem working > >> with older non-security-aware servers? Are they going > >> to fail when they get a response with an nscount of 2 > >> but only 1 actual NS RR? > > Paul Vixie has been consulted on most of these decisions. My understanding > > from what he has said is that older versions of BIND are quite insensitive > > as to what section RRs are returned in and should not have problems in > > these cases. > > That's nice. But I thought we were talking about standards, not some > implementation. There are other implementations. Your comment bears all the hall marks of a knee jerk response. > randy Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa08800; 15 Nov 95 3:04 EST Received: from holmes.umd.edu(128.8.10.48) by relay.tis.com via smap (g3.0.1) id xma003800; Wed, 15 Nov 95 02:42:38 -0500 Received: from UMDD (umdd.umd.edu [128.8.170.13]) by holmes.umd.edu(8.6.12/95Sep13) with SMTP id DAA10061; Wed, 15 Nov 1995 03:05:35 -0500 Message-Id: <199511150805.DAA10061@holmes.umd.edu> Received: by UMDD.UMD.EDU id 7934 ; 15 Nov 95 03:05:32 EST Received: by UMDD (Mailer R2.10 ptf000) id 7934; Wed, 15 Nov 95 03:05:32 EST Date: Wed, 15 Nov 95 03:00:16 EST From: Bruce Crabill Subject: Re: NSCOUNT In-Reply-To: Message received on Wed, 15 Nov 95 00:40:46 EST To: dns-security@TIS.COM >> If the above is true, then is there is problem working >> with older non-security-aware servers? Are they going >> to fail when they get a response with an nscount of 2 >> but only 1 actual NS RR? > >Paul Vixie has been consulted on most of these decisions. My understanding >from what he has said is that older versions of BIND are quite insensitive as >to what section RRs are returned in and should not have problems in these >cases. Thats nice, but there are other DNS implementations other than BIND in the world. Before we change something as basic as the NSCOUNT field's definition, I think we should consider the implications for more than one implementation (granted that BIND is by far the most popular). Bruce   Received: from relay.tis.com by neptune.TIS.COM id aa11322; 15 Nov 95 6:30 EST Received: from munnari.oz.au(128.250.1.21) by relay.tis.com via smap (g3.0.1) id xma004887; Wed, 15 Nov 95 06:08:30 -0500 Received: from mundamutti.cs.mu.OZ.AU by munnari.oz.au with SMTP (5.83--+1.3.1+0.50) id AA14355; Wed, 15 Nov 1995 22:31:14 +1100 (from kre@munnari.OZ.AU) To: Bruce Crabill Cc: dns-security@TIS.COM Subject: Re: NSCOUNT In-Reply-To: Your message of "Wed, 15 Nov 1995 03:00:16 EST." <199511150805.DAA10061@holmes.umd.edu> Date: Wed, 15 Nov 1995 22:30:28 +1100 Message-Id: <1817.816435028@munnari.OZ.AU> From: Robert Elz Date: Wed, 15 Nov 95 03:00:16 EST From: Bruce Crabill Message-ID: <199511150805.DAA10061@holmes.umd.edu> Before we change something as basic as the NSCOUNT field's definition, I think we should consider the implications for more than one implementation Is there anyone associated with any implementation complaining about this proposed change, or is this purely imaging what might possibly be problems for implementations they imagine might exist? The general "be liberal in what you receive" principal would tend to suggest that implementations should do no worse than logging an error message when seeing an unexpected type in the authority field. If someone could post the name of a nameserver, and a query to try, that will provoke a response with a SIG in the Auth field, then people with various implementations in use could actually try that query and see if their nameserver has any problems and report that to the list. Hypothetical speculation will get us nowhere. kre   Received: from relay.tis.com by neptune.TIS.COM id aa16331; 15 Nov 95 10:36 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma008444; Wed, 15 Nov 95 10:15:11 -0500 Received: by callandor.cybercash.com; id KAA02881; Wed, 15 Nov 1995 10:38:18 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma002878; Wed, 15 Nov 95 10:38:11 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA15441; Wed, 15 Nov 95 10:36:34 EST Date: Wed, 15 Nov 1995 10:36:34 -0500 (EST) From: "Donald E. Eastlake 3rd" To: dns-security@TIS.COM Subject: Re: NSCOUNT (fwd) Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII I looked at RFC 1035 and found that it provides in section 3.7 for servers, at their option, to include SOA RRs in the authority section and in fact an example of this is given in section 6.2.5. So it was never true that NSCOUNT was only a count of NS RRs. Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA) ---------- Forwarded message ---------- Date: Wed, 15 Nov 1995 00:13:06 -0500 (EST) From: Donald E. Eastlake 3rd To: "Edie E. Gunter" Cc: dns-security@TIS.COM Subject: Re: NSCOUNT Edie, On Tue, 14 Nov 1995, Edie E. Gunter wrote: > The DNSSEC draft seems to suggest that if DNS returns an NS > RR in the authority section of a query response, then the > SIG should also be included in the authority section of the > response. Is this correct? Yes, the idea being that you wouldn't want additional info to cause loss of the AIG authentication the authority info (or authority info to cause loss of the SIG for the main response) due to truncation. > If so, then it seems that in order for the message to be > parsed correctly, the NSCOUNT field would have to be set to > 2 instead of 1, to account for the SIG and the NS RR. Or possibly more for multiple SIGs. Also, the NXT RR authenticating the non-existence of a name appears in the authority section. > But, the NSCOUNT field is defined (RFC 883, 1035 and elsewhere) > to be the number of NS RRs in the authority section. > So, it seems that the DNSSEC draft is redefining the > meaning of the NSCOUNT field, though I don't see this > mentioned explicitly. You are correction and I guess this should be added to the draft. > If the above is true, then is there is problem working > with older non-security-aware servers? Are they going > to fail when they get a response with an nscount of 2 > but only 1 actual NS RR? Paul Vixie has been consulted on most of these decisions. My understanding from what he has said is that older versions of BIND are quite insensitive as to what section RRs are returned in and should not have problems in these cases. > Edie Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa20811; 15 Nov 95 14:46 EST Received: from holmes.umd.edu(128.8.10.48) by relay.tis.com via smap (g3.0.1) id xma013658; Wed, 15 Nov 95 14:24:54 -0500 Received: from UMDD (umdd.umd.edu [128.8.170.13]) by holmes.umd.edu(8.6.12/95Sep13) with SMTP id OAA10755; Wed, 15 Nov 1995 14:47:53 -0500 Message-Id: <199511151947.OAA10755@holmes.umd.edu> Received: by UMDD.UMD.EDU id 6604 ; 15 Nov 95 14:47:50 EST Received: by UMDD (Mailer R2.10 ptf000) id 6604; Wed, 15 Nov 95 14:47:49 EST Date: Wed, 15 Nov 95 14:44:36 EST From: Bruce Crabill Subject: Re: NSCOUNT (fwd) In-Reply-To: Message received on Wed, 15 Nov 95 11:40:14 EST To: dns-security@TIS.COM >I looked at RFC 1035 and found that it provides in section 3.7 for servers, >at their option, to include SOA RRs in the authority section and in fact an >example of this is given in section 6.2.5. So it was never true that NSCOUNT >was only a count of NS RRs. > >Donald I think you meant RFC 1034. RFC 1035 doesn't have those section numbers and defines (in section 4.1.1.) that NSCOUNT is the number of name server resource records. But you are right, RFC 1034 does add the thing about a SOA as also being a possibility. Bruce   Received: from relay.tis.com by neptune.TIS.COM id aa14730; 16 Nov 95 13:44 EST Received: from gw.home.vix.com(192.5.5.1) by relay.tis.com via smap (g3.0.1) id xma001691; Thu, 16 Nov 95 13:22:28 -0500 Received: by gw.home.vix.com id AA19980; Thu, 16 Nov 95 10:45:40 -0800 Date: Thu, 16 Nov 95 10:45:40 -0800 X-Btw: vix.com is also gw.home.vix.com and vixie.sf.ca.us To: dns-security@TIS.COM From: Paul A Vixie Subject: Re: NSCOUNT Organization: Vixie Enterprises Message-Id: References: <9511142159.AA18904@edisto.watson.ibm.com> Nntp-Posting-Host: wisdom.home.vix.com In-Reply-To: dee@cybercash.com's message of 14 Nov 1995 21:41:07 -0800 >Paul Vixie has been consulted on most of these decisions. My understanding >from what he has said is that older versions of BIND are quite insensitive as >to what section RRs are returned in and should not have problems in these >cases. BIND treats NSCOUNT as "the number of records in the authority section" and I think this is the intent of PVM's original spec -- the reason it may have been described as "the number of NS records in the authority section" is only because the authority section could only contain NS records at that time and PVM overspecified. I think it's safe to redefine this as long as we do so explicitly. -- Paul Vixie La Honda, CA "Illegitimibus non carborundum." pacbell!vixie!paul   Received: from relay.tis.com by neptune.TIS.COM id aa12610; 17 Nov 95 15:28 EST Received: from watson.ibm.com(129.34.139.4) by relay.tis.com via smap (g3.0.1) id xma028652; Fri, 17 Nov 95 15:06:16 -0500 Received: from WATSON by watson.ibm.com (IBM VM SMTP V2R3) with BSMTP id 4469; Fri, 17 Nov 95 15:29:43 EST Received: from YKTVMV by watson.vnet.ibm.com with "VAGENT.V1.02 on VAGENT2" id 8437; Fri, 17 Nov 1995 15:29:43 EST Received: from edisto.watson.ibm.com by yktvmv.watson.ibm.com (IBM VM SMTP V2Rx) with TCP; Fri, 17 Nov 95 15:29:42 EST Received: by edisto.watson.ibm.com (AIX 3.2/UCB 5.64/900524) id AA17231; Fri, 17 Nov 1995 15:29:32 -0500 Message-Id: <9511172029.AA17231@edisto.watson.ibm.com> X-External-Networks: yes To: dns-security@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: Your message of Wed, 15 Nov 95 00:31:32 EST. Date: Fri, 17 Nov 95 15:29:32 -0500 From: "Edie E. Gunter" > If a DNS server is security ignorant, it obviously does nothing when a > SIG expires. If it's security aware, it shouldn't send out an RR > whose SIG has expired and if it was caching it should purge them. > It's not quite so clear to me if it was not cahcing but a primary or > secondary server and I don't think it matters much. You clearly have > a problem of not having re-signed and reloaded the zone soon enough. > I don't think this case is covered in the current draft. It does not > seem to matter much to me if the RR is purged or just keep around and > not provided in answers (except in a zone transfer so the AXFR is right > (except that it would probably be the case that if one zone signed SIG > has expired, they all have, and you are totally out of it)). So, what would you expect to happen when all the SIGs for a zone expire, including that for the SOA? Would the server just start rejecting every query with SERVFAIL/REFUSED? Or should the server alert the sys_admin and terminate? Or is this detail just left up to the implementation to decide? Anyone know what TIS is doing in this case? Edie   Received: from relay.tis.com by neptune.TIS.COM id aa01459; 21 Nov 95 16:30 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma018053; Tue, 21 Nov 95 16:08:36 -0500 Received: by callandor.cybercash.com; id QAA11204; Tue, 21 Nov 1995 16:33:11 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma011201; Tue, 21 Nov 95 16:33:01 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA02564; Tue, 21 Nov 95 16:30:44 EST Date: Tue, 21 Nov 1995 16:30:44 -0500 (EST) From: "Donald E. Eastlake 3rd" To: "Edie E. Gunter" Cc: dns-security@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: <9511172029.AA17231@edisto.watson.ibm.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Things like alerting the system administrator seem like local policy issues. If all the SIGs have expired, seems like a secure server should act like it had never had any data for the zone loaded. Donald On Fri, 17 Nov 1995, Edie E. Gunter wrote: > > If a DNS server is security ignorant, it obviously does nothing when a > > SIG expires. If it's security aware, it shouldn't send out an RR > > whose SIG has expired and if it was caching it should purge them. > > It's not quite so clear to me if it was not cahcing but a primary or > > secondary server and I don't think it matters much. You clearly have > > a problem of not having re-signed and reloaded the zone soon enough. > > I don't think this case is covered in the current draft. It does not > > seem to matter much to me if the RR is purged or just keep around and > > not provided in answers (except in a zone transfer so the AXFR is right > > (except that it would probably be the case that if one zone signed SIG > > has expired, they all have, and you are totally out of it)). > > So, what would you expect to happen when all the SIGs for a > zone expire, including that for the SOA? Would the server > just start rejecting every query with SERVFAIL/REFUSED? Or > should the server alert the sys_admin and terminate? Or is > this detail just left up to the implementation to decide? > > Anyone know what TIS is doing in this case? > > Edie > ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa18217; 22 Nov 95 11:17 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma000335; Wed, 22 Nov 95 10:54:22 -0500 Received: by callandor.cybercash.com; id LAA19508; Wed, 22 Nov 1995 11:19:13 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma019504; Wed, 22 Nov 95 11:19:05 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA09168; Wed, 22 Nov 95 11:16:43 EST Date: Wed, 22 Nov 1995 11:16:42 -0500 (EST) From: "Donald E. Eastlake 3rd" To: "Edie E. Gunter" Cc: dns-security@TIS.COM Subject: Re: "Null" SIGs, NXT ordering, SIG orig TTL In-Reply-To: <9510101352.AA19385@edisto.watson.ibm.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII I think some of these have already been answered but I'll give it a try also... On Tue, 10 Oct 1995, Edie E. Gunter wrote: > I have a few comments on the draft... > > - Section 3 says: > > Security > aware DNS implementations MUST be designed to handle at least two > simultaneously valid keys of the same type associated with a name. > > Why isn't the ability to handle one enough? Why MUST two valid > keys be supported? Optional support of more than one is fine. > (Why would anyone want more than one KEY of the same type, anyway?) Basicly for key rollover. If a new key is being introduced for a zone, it may take a while for the superzone and various boot files to get update during which time you would want both keys to be used. And if the key is being used in some non-DNS protocol, where DNS is just being used for key distribution, you can have similar problems. > - Section 3.7 refers to type AAAA RR's. What are these? AAAA are the IPv6 equivalent of A. > - Section 4 says: > > The SIG RR unforgably authenticates other RRs of a particular type, > class, and name and binds them to a time interval and the signer's > domain name. > > If this is true, why isn't the SIG on a dynamic update sufficient > to make that name/RR a full-fledged part of the DNS database, > allowing dynamically updated data to be treated just like "static" > data? If this is true, why do we even need the distinction of > static versus dynamic RRs? The essence of the secrity of static RRs, as recommended by DNSsec is that the data, key, and signing are all done off-line so that even corruption of all the servers serving that zone can not lead to spoofing valid RRs to someone who has the zone public key. Any dynamic on-line scheme, including dynamic update, requires the private key on line which means that compromise of that machine breaks your security. > - Section 4.1.3 says: > > Thus > such dynamic RRs are not directly signed by the zone, are not > included in the AXFR SIG, and are not generally protected against > omission from zone transfers. > > I am quite sure this is not what anyone running a secure DNS that > supports secure dynamic updates would want. It seems this section > should cover how to securely include dynamic updates in a zone transfer -- > if not via the method described in 4.1.3 using AXFR SIG, etc. then by > some other method. If something is being updated on-line, you are completely trusting the server to do the right thing. After all, it could tell you that the update was complete but actually ignore it. So if you trust that machine, you can get a trusted zone transfer by using the DNSsec transaction security feature or otherwise having secure communications with it. I'll change the wording to reflect that. > - Section 4.3 says: > > Only a proper SIG RR signed by the zone can authenticate RRs. > > What about entity signed dynamic RRs? I'll fix that. > - Section 4.4 Signature Expiration > > When a SIG expires, the covered RR's are not removed from the database, > but are kept around and the AD bit is used to indicate if the data > is no longer authentic. Is that right? Nope, AD is used only to indicate whether data is (1) Pending or (2) Authentic or Insecure. (Insecure means it has been proven that the data can't authenticated or proved bad becasue it's in or accessed via an non-secure zone or the like.) Data with expired SIG are removed in the TIS implementation, I believe, but would never be returned in any case. > - Section 5.1 says: > > The NXT RRs for a zone should be automatically calculated and added > to the zone by the same recommended off-line process that signs the > zone. > > What about dynamic updates? Can't you get into a situation where > something was added via a dynamic update and the NXT RR computed at > start-up is no longer correct? It seems to me that these NXT RR's > must be computed on the fly to be accurate in the face of dynamic > updates. As answered elsewhere, dynamic updates can't change the name structure as they are authorized by KEYs that have already covered the name for any possible additions. Dynamic updates can, however, change what types exist so I will change the draft to indicate that the NXT type bits only cover zone signed RRs. > - Section 6 says: > > Authenticated means that the data has a valid SIG under a KEY > traceable via a chain of zero or more SIG and KEY RRs to a KEY > configured at the resolver via its boot file. > > So, if the KEY RR for a name was in the statically read master > file for the zone, then RR's added dynamically and signed with > the private part of that KEY are considered authenticated? Yes. > - Section 6.1 says: > > Security aware servers never return Bad data. > > Is this true, given that zone transfers may omit dynamically added > RR's and given that NXT RR's are calculated offline? Perhaps I > don't understand the definition of Bad data here. "Bad" data is data for which their should be authenticating SIGs but for which all the SIGs have been checked and they all either fail or have expired. (If they have not all been checked yet, the data is Pending.) > - Section 6.3 says: > > A resolver should keep track of the number of successive secure zones > traversed from a starting point to any secure zone it can reach. <...> > Should a query encounter > different data for the same query with different distance values, > that with a larger value should be ignored. > > I don't see exactly how this is supposed to work. Are you suggesting > that after sending out a query, the client waits around for multiple > query responses and then picks the one with the lower distance value? > In practice, wouldn't a client just take the first response with > a non-empty answer section and use that? Sure. The comment applies to the case of conflicting data in the cache. > - Section 7.2 says: > > Periodically an application can be > run to re-sign the RRs in a zone by adding NXT and SIG RRs. > > It seems to get dynamic updates to work within the DNSSEC framework, > this period would have to be such that everything is re-signed > after each dynamic update. The update becomes part of the "static" > data and all the "static" data is then resigned. No, this can't be right. If you wanted to keep the zone owner private key on line and have everything zone signed, you would have to at least re-sign the SOA, AXFR, and maybe a changed NXT (due to type bit map) or two after each dynamic update but you won't have to re-sign everything. > - Section 7.5 says: > > It is recommended that signature lifetime be a small multiple of the > TTL but not less than a reasonable re-signing interval. > > In an environment where DHCP is used to hand out IP address leases > and DNS is updated dynamically to reflect the lease information, > the lifetime of the data will usually be that of the lease duration. > In the case of mobile clients, this lease duration may be just 5 - 10 > minutes. That said, what is your idea of a reasonable re-signing interval? This was meant to apply to the off line zone signing procedure. I'll add some words to the effect that shorter times are fine if you *want* the data to expire sooner (in which case the TTL should be shorter also). > - Also, it was mentioned to me in private email that: > > if you want a completely dynamic zone, you can just have > the zone key sign an entity key with wildcard authority over the > entire zone and then use the entity key for everything in the zone > > I don't see anything like this discussed in the draft -- > particularly with respect to zone transfers and handling > NXT records. (And if there really is this other way to do security > in DNS servers that support dynamic updates, I'd really > like to understand how it would work!) It's not an "other way", it's just a way, completely within the framework contemplated in the DNSsec draft, to move almost everything from the fixed master file to the dynamic master file... If you have a wildcard entity key covering the whole zone, there are only two NXT records ever (one with an owner name of the zone name and one with an owner name of the zone wide wildcard name). If you want update keys with more limited scope, they could be signed by either the zone key or this zone wide update key. > Edie Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa19080; 22 Nov 95 12:03 EST Received: from callandor.cybercash.com(204.178.186.70) by relay.tis.com via smap (g3.0.1) id xma001021; Wed, 22 Nov 95 11:26:52 -0500 Received: by callandor.cybercash.com; id LAA19918; Wed, 22 Nov 1995 11:51:13 -0500 Received: from cybercash.com(204.254.34.52) by callandor.cybercash.com via smap (g3.0.3) id xma019914; Wed, 22 Nov 95 11:50:48 -0500 Received: by cybercash.com.cybercash.com (4.1/SMI-4.1) id AA09678; Wed, 22 Nov 95 11:48:22 EST Date: Wed, 22 Nov 1995 11:48:21 -0500 (EST) From: "Donald E. Eastlake 3rd" To: "Edie E. Gunter" Cc: dnssec@fireball.lz.att.com, dns-security@TIS.COM MMDF-Warning: Unable to confirm address in preceding line at neptune.TIS.COM Subject: Re: A Simple Question In-Reply-To: <9511101845.AA18042@edisto.watson.ibm.com> Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Fri, 10 Nov 1995, Edie E. Gunter wrote: > > So I'm a security aware resolver and I query for, say, Type A records > > on name A.B.C.D. I get back an A record and a SIG record: > > > > A.B.C.D IN A [some ttl] 135.24.40.12 > > A.B.C.D IN SIG [some ttl] [Type A SIG RDATA] > > > > How do I figure out which public KEY I'm supposed to use to > > authenticate the A record? > > The RR's for A.B.C.D can be signed by the entity A.B.C.D > and/or the zone. So, if you don't have the public key for > A.B.C.D and/or the zone, you'll have to query the > server for those KEY RR's also (perhaps using transaction SIGs if > you're really paranoid.) > > Now, there can be multiple keys per name. (i.e. A.B.C.D may > have multiple KEY RRs for the same algorithm type.) The best > explanation I've heard for handling this is to just > try them all and see if any work... That should almost never be necessary. It's the primary reason for the 16 bit "key footprint" field in the SIG RR. Unless you have a log of zone and/or entity keys, the probability should be very low that two have the same footprint. > All KEY RR's are signed by the zone. (Well, in principle, you could have an entity key for B.C.D sign an entity key for A.B.C.D but I don't know if that feature will be used in practice.) > W.X.Y.Z can't generate a SIG for A.B.C.D unless it knows > either the private key for A.B.C.D or the private key for > the zone (and you're allowing dynamic updates.) W.X.Y.Z should > never know another name's private key. Once the private key is > exposed, you're no longer secure. > > Edie Donald ===================================================================== Donald E. Eastlake 3rd +1 508-287-4877(tel) dee@cybercash.com 318 Acton Street +1 508-371-7148(fax) dee@world.std.com Carlisle, MA 01741 USA +1 703-620-4200(main office, Reston, VA)   Received: from relay.tis.com by neptune.TIS.COM id aa09106; 27 Nov 95 10:12 EST Received: from mailhost1.primenet.com(198.68.32.51) by relay.tis.com via smap (g3.0.1) id xma012739; Mon, 27 Nov 95 09:50:00 -0500 Received: from usr2.primenet.com (root@usr2.primenet.com [198.68.32.12]) by mailhost1.primenet.com (8.7.1/8.7.1) with ESMTP id IAA08739 for ; Mon, 27 Nov 1995 08:14:23 -0700 (MST) Received: from ip141.flg.primenet.com (ip141.flg.primenet.com [198.68.40.141]) by usr2.primenet.com (8.7.1/8.7.1) with SMTP id IAA14634 for ; Mon, 27 Nov 1995 08:14:22 -0700 (MST) Date: Mon, 27 Nov 1995 08:14:22 -0700 (MST) Message-Id: <199511271514.IAA14634@usr2.primenet.com> X-Sender: srm@mailhost.primenet.com X-Mailer: Windows Eudora Version 1.4.3 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: dns-security@TIS.COM From: "Scott R. Mesneak" Subject: unsubscribe unsubscribe   Received: from relay.tis.com by neptune.TIS.COM id aa15679; 27 Nov 95 15:58 EST Received: from ec-mail.bsan.com(199.250.176.75) by relay.tis.com via smap (g3.0.1) id xma018457; Mon, 27 Nov 95 15:35:07 -0500 Received: from bprice.bsan.com (m22.bsan.com) by bellsouth.net (5.x/SMI-SVR4) id AA14673; Mon, 27 Nov 1995 15:58:35 -0500 Date: Mon, 27 Nov 95 15:58:49 est From: Bill Price Subject: subscribe To: dns-security@TIS.COM X-Mailer: Chameleon ARM_55, TCP/IP for Windows, NetManage Inc. Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII ------------------------------------- E-mail: bprice@bsan.com General Manager, Internet Services BellSouth Date: 11/27/95 Time: 15:58:49 This message was sent by Chameleon -------------------------------------   Received: from relay.tis.com by neptune.TIS.COM id aa23092; 30 Nov 95 13:29 EST Received: from sol.tis.com(192.33.112.100) by relay.tis.com via smap (g3.0.1) id xma004373; Thu, 30 Nov 95 13:05:59 -0500 Received: from antares.tis.com by tis.com (4.1/SUN-5.64) id AA12393; Thu, 30 Nov 95 13:29:00 EST Message-Id: <9511301829.AA12393@tis.com> Reply-To: James M Galvin To: dns-security@TIS.COM Subject: Agenda for Dallas IETF Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Id: <12059.817756170.1@tis.com> Date: Thu, 30 Nov 1995 13:29:31 -0500 From: James M Galvin Sorry for the late posting. In case you haven't noticed, the meeting is scheduled for Tuesday during the 9am meeting slot. I've got three items for the agenda: o specification status - DNS security - Autonomous system numbers o implementation status o dynamic update - charter update - technical issues With respect to the latter item, many of you already know that those working on dynamic update have asked that we accept as a work item to address security issues. Our security area director has, in fact, told me as Chair that we will do this. As a strictly procedural issue, we need to update our charter to reflect this new work item. I expect we will spend most of our time on dynamic update issues unless, of course, no one is prepared to discuss them. See you in Dallas, Jim