Keywords: lightweight, directory, access, protocol, DSA-specific, entry
Network Working Group M. Meredith
Request for Comments: 3045 Novell Inc.
Category: Informational January 2001
Storing Vendor Information in the LDAP root DSE
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This document specifies two Lightweight Directory Access Protocol
(LDAP) attributes, vendorName and vendorVersion that MAY be included
in the root DSA-specific Entry (DSE) to advertise vendor-specific
information. These two attributes supplement the attributes defined
in section 3.4 of RFC 2251.
The information held in these attributes MAY be used for display and
informational purposes and MUST NOT be used for feature advertisement
or discovery.
Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2219]
1. Overview
LDAP clients discover server-specific data--such as available
controls, extensions, etc.--by reading the root DSE. See section 3.4
of [RFC2251] for details.
For display, information, and limited function discovery, it is
desirable to be able to query an LDAP server to determine the vendor
name of that server and also to see what version of that vendor's
code is currently installed.
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1.1 Function discovery
There are many ways in which a particular version of a vendor's LDAP
server implementation may be functionally incomplete, or may contain
software anomalies. It is impossible to identify every known
shortcoming of an LDAP server with the given set of server data
advertisement attributes. Furthermore, often times, the anomalies of
an implementation are not found until after the implementation has
been distributed, deployed, and is in use.
The attributes defined in this document MAY be used by client
implementations in order to identify a particular server
implementation so that it can 'work around' such anomalies.
The attributes defined in this document MUST NOT be used to gather
information related to supported features of an LDAP implementation.
All LDAP features, mechanisms, and capabilities--if advertised--MUST
be advertised through other mechanisms, preferably advertisement
mechanisms defined in concert with said features, mechanisms, and
capabilities.
2. Attribute Types
These attributes are an addition to the Server-specific Data
Requirements defined in section 3.4 of [RFC2251]. The associated
syntaxes are defined in section 4 of [RFC2252].
Servers MAY restrict access to vendorName or vendorVersion and
clients MUST NOT expect these attributes to be available.
2.1 vendorName
This attribute contains a single string, which represents the name of
the LDAP server implementer.
All LDAP server implementations SHOULD maintain a vendorName, which
is generally the name of the company that wrote the LDAP Server code
like "Novell, Inc."
( 1.3.6.1.1.4 NAME 'vendorName' EQUALITY
1.3.6.1.4.1.1466.109.114.1 SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
SINGLE-VALUE NO-USER-MODIFICATION USAGE dSAOperation )
2.2 vendorVersion
This attribute contains a string which represents the version of the
LDAP server implementation.
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All LDAP server implementations SHOULD maintain a vendorVersion.
Note that this value is typically a release value--comprised of a
string and/or a string of numbers--used by the developer of the LDAP
server product (as opposed to the supportedLDAPVersion, which
specifies the version of the LDAP protocol supported by this server).
This is single-valued so that it will only have one version value.
This string MUST be unique between two versions, but there are no
other syntactic restrictions on the value or the way it is formatted.
( 1.3.6.1.1.5 NAME 'vendorVersion' EQUALITY
1.3.6.1.4.1.1466.109.114.1 SYNTAX 1.3.6.1.4.1.1466.115.121.1.15
SINGLE-VALUE NO-USER-MODIFICATION USAGE dSAOperation )
The intent behind the equality match on vendorVersion is to not allow
a less than or greater than type of query. Say release "LDAPv3 8.0"
has a problem that is fixed in the next release "LDAPv3 8.5", but in
the mean time there is also an update release say version "LDAPv3
8.01" that fixes the problem. This will hopefully stop the client
from saying it will not work with a version less than "LDAPv3 8.5"
when it would also work with "LDAPv3 8.01". With the equality match
the client would have to exactly match what it is looking for.
3. Notes to Server Implementers
Server implementers may consider tying the vendorVersion attribute
value to the build mechanism so that it is automatically updated when
the version value changes.
4. Notes to Client Developers
As mentioned in section 2.1, the use of vendorName and vendorVersion
MUST NOT be used to discover features.
It should be noted that an anomalies often on affect subset of
implementations reporting the same version information. Most
implementations support multiple platforms, have numerous
configuration options, and often support plug-ins.
Client implementations SHOULD be written in such a way as to accept
any value in the vendorName and vendorVersion attributes. If a
client implementation does not recognize the specific vendorName or
vendorVersion as one it recognizes, then for the purposes of 'working
around' anomalies, the client MUST assume that the server is complete
and correct. The client MUST work with implementations that do not
publish these attributes.
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RFC 3045 LDAP Root DSE to Display Vendor Information January 2001
5. Security Considerations
The vendorName and vendorVersion attributes are provided only as
display or informational mechanisms, or as anomaly identifying
mechanisms. Client and application implementers must consider that
the existence of a given value in the vendorName or vendorVersion
attribute is no guarantee that the server was actually built by the
asserted vendor or that its version is the asserted version and
should act accordingly.
Server implementers should be aware that this information could be
used to exploit a security hole a server provides either by feature
or flaw.
6. IANA Considerations
This document seeks to create two attributes, vendorName and
vendorVersion, which the IANA will primarily be responsible. This is
a one time effort; there is no need for any recurring assignment
after this stage.
7. References
[RFC2219] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996.
[RFC2251] Wahl, M., Howes, T. and S. Kille, "Lightweight Directory
Access Protocol (v3)", RFC 2251, December 1997.
[RFC2252] Wahl, M., Coulbeck, A., Howes, T. and S. Kille,
"Lightweight Directory Access Protocol (v3): Attribute
Syntax Definitions", RFC 2252, December 1997.
8. Acknowledgments
The author would like to thank the generous input and review by
individuals at Novell including but not limited to Jim Sermersheim,
Mark Hinckley, Renea Campbell, and Roger Harrison. Also IETF
contributors Kurt Zeilenga, Mark Smith, Mark Wahl, Peter Strong,
Thomas Salter, Gordon Good, Paul Leach, Helmut Volpers.
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9. Author's Address
Mark Meredith
Novell Inc.
1800 S. Novell Place
Provo, UT 84606
Phone: 801-861-2645
EMail: mark_meredith@novell.com
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10. Full Copyright Statement
Copyright (C) The Internet Society (2001). All Rights Reserved.
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Acknowledgement
Funding for the RFC Editor function is currently provided by the
Internet Society.
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