draft-ietf-ldapbis-strprep-07.txt   rfc4518.txt 
Internet-Draft Kurt D. Zeilenga Network Working Group K. Zeilenga
Intended Category: Standard Track OpenLDAP Foundation Request for Comments: 4518 OpenLDAP Foundation
Expires in six months 23 January 2006 Lightweight Directory Access Protocol (LDAP):
Internationalized String Preparation
LDAP: Internationalized String Preparation
<draft-ietf-ldapbis-strprep-07.txt>
Status of this Memo
This document is intended to be published as a Standard Track RFC.
Distribution of this memo is unlimited. Technical discussion of this
document will take place on the IETF LDAP Revision Working Group
mailing list <ietf-ldapbis@openldap.org>. Please send editorial
comments directly to the editor <Kurt@OpenLDAP.org>.
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware have
been or will be disclosed, and any of which he or she becomes aware
will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at Status of This Memo
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at This document specifies an Internet standards track protocol for the
http://www.ietf.org/shadow.html Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (2006). All Rights Reserved. Copyright Notice
Please see the Full Copyright section near the end of this document Copyright (C) The Internet Society (2006).
for more information.
Abstract Abstract
The previous Lightweight Directory Access Protocol (LDAP) technical The previous Lightweight Directory Access Protocol (LDAP) technical
specifications did not precisely define how character string matching specifications did not precisely define how character string matching
is to be performed. This led to a number of usability and is to be performed. This led to a number of usability and
interoperability problems. This document defines string preparation interoperability problems. This document defines string preparation
algorithms for character-based matching rules defined for use in LDAP. algorithms for character-based matching rules defined for use in
LDAP.
Conventions and Terms
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 BCP 14 [RFC2119].
Character names in this document use the notation for code points and
names from the Unicode Standard [Unicode]. For example, the letter
"a" may be represented as either <U+0061> or <LATIN SMALL LETTER A>.
In the lists of mappings and the prohibited characters, the "U+" is
left off to make the lists easier to read. The comments for character
ranges are shown in square brackets (such as "[CONTROL CHARACTERS]")
and do not come from the standard.
Note: a glossary of terms used in Unicode can be found in [Glossary].
Information on the Unicode character encoding model can be found in
[CharModel].
The term "combining mark", as used in this specification, refers to
any Unicode [Unicode] code point which has a mark property (Mn, Mc,
Me). Appendix A provides a definitive list of combining marks.
1. Introduction 1. Introduction
1.1. Background 1.1. Background
A Lightweight Directory Access Protocol (LDAP) [Roadmap] matching rule A Lightweight Directory Access Protocol (LDAP) [RFC4510] matching
[Syntaxes] defines an algorithm for determining whether a presented rule [RFC4517] defines an algorithm for determining whether a
value matches an attribute value in accordance with the criteria presented value matches an attribute value in accordance with the
defined for the rule. The proposition may be evaluated to True, criteria defined for the rule. The proposition may be evaluated to
False, or Undefined. True, False, or Undefined.
True - the attribute contains a matching value, True - the attribute contains a matching value,
False - the attribute contains no matching value, False - the attribute contains no matching value,
Undefined - it cannot be determined whether the attribute contains Undefined - it cannot be determined whether the attribute contains
a matching value or not. a matching value.
For instance, the caseIgnoreMatch matching rule may be used to compare For instance, the caseIgnoreMatch matching rule may be used to
whether the commonName attribute contains a particular value without compare whether the commonName attribute contains a particular value
regard for case and insignificant spaces. without regard for case and insignificant spaces.
1.2. X.500 String Matching Rules 1.2. X.500 String Matching Rules
"X.520: Selected attribute types" [X.520] provides (amongst other "X.520: Selected attribute types" [X.520] provides (among other
things) value syntaxes and matching rules for comparing values things) value syntaxes and matching rules for comparing values
commonly used in the Directory. These specifications are inadequate commonly used in the directory [X.500]. These specifications are
for strings composed of Unicode [Unicode] characters. inadequate for strings composed of Unicode [Unicode] characters.
The caseIgnoreMatch matching rule [X.520], for example, is simply The caseIgnoreMatch matching rule [X.520], for example, is simply
defined as being a case insensitive comparison where insignificant defined as being a case-insensitive comparison where insignificant
spaces are ignored. For printableString, there is only one space spaces are ignored. For printableString, there is only one space
character and case mapping is bijective, hence this definition is character and case mapping is bijective, hence this definition is
sufficient. However, for Unicode string types such as sufficient. However, for Unicode string types such as
universalString, this is not sufficient. For example, a case universalString, this is not sufficient. For example, a case-
insensitive matching implementation which folded lower case characters insensitive matching implementation that folded lowercase characters
to upper case would yield different different results than an to uppercase would yield different results than an implementation
implementation which used upper case to lower case folding. Or one that used uppercase to lowercase folding. Or one implementation may
implementation may view space as referring to only SPACE (U+0020), a view space as referring to only SPACE (U+0020), a second
second implementation may view any character with the space separator implementation may view any character with the space separator (Zs)
(Zs) property as a space, and another implementation may view any property as a space, and another implementation may view any
character with the whitespace (WS) category as a space. character with the whitespace (WS) category as a space.
The lack of precise specification for character string matching has The lack of precise specification for character string matching has
led to significant interoperability problems. When used in led to significant interoperability problems. When used in
certificate chain validation, security vulnerabilities can arise. To certificate chain validation, security vulnerabilities can arise. To
address these problems, this document defines precise algorithms for address these problems, this document defines precise algorithms for
preparing character strings for matching. preparing character strings for matching.
1.3. Relationship to "stringprep" 1.3. Relationship to "stringprep"
The character string preparation algorithms described in this document The character string preparation algorithms described in this
are based upon the "stringprep" approach [RFC3454]. In "stringprep", document are based upon the "stringprep" approach [RFC3454]. In
presented and stored values are first prepared for comparison and so "stringprep", presented and stored values are first prepared for
that a character-by-character comparison yields the "correct" result. comparison so that a character-by-character comparison yields the
"correct" result.
The approach used here is a refinement of the "stringprep" [RFC3454] The approach used here is a refinement of the "stringprep" [RFC3454]
approach. Each algorithm involves two additional preparation steps. approach. Each algorithm involves two additional preparation steps.
a) prior to applying the Unicode string preparation steps outlined in a) Prior to applying the Unicode string preparation steps outlined in
"stringprep", the string is transcoded to Unicode; "stringprep", the string is transcoded to Unicode.
b) after applying the Unicode string preparation steps outlined in b) After applying the Unicode string preparation steps outlined in
"stringprep", the string is modified to appropriately handle "stringprep", the string is modified to appropriately handle
characters insignificant to the matching rule. characters insignificant to the matching rule.
Hence, preparation of character strings for X.500 matching involves Hence, preparation of character strings for X.500 [X.500] matching
the following steps: [X.501] involves the following steps:
1) Transcode 1) Transcode
2) Map 2) Map
3) Normalize 3) Normalize
4) Prohibit 4) Prohibit
5) Check Bidi (Bidirectional) 5) Check Bidi (Bidirectional)
6) Insignificant Character Handling 6) Insignificant Character Handling
These steps are described in Section 2. These steps are described in Section 2.
It is noted that while various tables of Unicode characters included It is noted that while various tables of Unicode characters included
or referenced by this specification are derived from Unicode [UNICODE] or referenced by this specification are derived from Unicode
data, these tables are to be considered definitive for the purpose of [Unicode] data, these tables are to be considered definitive for the
implementing this specification. purpose of implementing this specification.
1.4. Relationship to the LDAP Technical Specification 1.4. Relationship to the LDAP Technical Specification
This document is a integral part of the LDAP technical specification This document is an integral part of the LDAP technical specification
[Roadmap] which obsoletes the previously defined LDAP technical [RFC4510], which obsoletes the previously defined LDAP technical
specification [RFC3377] in its entirety. specification [RFC3377] in its entirety.
This document details new LDAP internationalized character string This document details new LDAP internationalized character string
preparation algorithms used by [Syntaxes] and possible other technical preparation algorithms used by [RFC4517] and possible other technical
specifications defining LDAP syntaxes and/or matching rules. specifications defining LDAP syntaxes and/or matching rules.
1.5. Relationship to X.500 1.5. Relationship to X.500
LDAP is defined [Roadmap] in X.500 terms as an X.500 access mechanism. LDAP is defined [RFC4510] in X.500 terms as an X.500 access
As such, there is a strong desire for alignment between LDAP and X.500 mechanism. As such, there is a strong desire for alignment between
syntax and semantics. The character string preparation algorithms LDAP and X.500 syntax and semantics. The character string
described in this document are based upon "Internationalized String preparation algorithms described in this document are based upon
Matching Rules for X.500" [XMATCH] proposal to ITU/ISO Joint Study "Internationalized String Matching Rules for X.500" [XMATCH] proposal
Group 2. to ITU/ISO Joint Study Group 2.
1.6. Conventions and Terms
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 BCP 14 [RFC2119].
Character names in this document use the notation for code points and
names from the Unicode Standard [Unicode]. For example, the letter
"a" may be represented as either <U+0061> or <LATIN SMALL LETTER A>.
In the lists of mappings and the prohibited characters, the "U+" is
left off to make the lists easier to read. The comments for
character ranges are shown in square brackets (such as "[CONTROL
CHARACTERS]") and do not come from the standard.
Note: a glossary of terms used in Unicode can be found in [Glossary].
Information on the Unicode character encoding model can be found in
[CharModel].
The term "combining mark", as used in this specification, refers to
any Unicode [Unicode] code point that has a mark property (Mn, Mc,
Me). Appendix A provides a definitive list of combining marks.
2. String Preparation 2. String Preparation
The following six-step process SHALL be applied to each presented and The following six-step process SHALL be applied to each presented and
attribute value in preparation for character string matching rule attribute value in preparation for character string matching rule
evaluation. evaluation.
1) Transcode 1) Transcode
2) Map 2) Map
3) Normalize 3) Normalize
4) Prohibit 4) Prohibit
5) Check bidi 5) Check bidi
6) Insignificant Character Handling 6) Insignificant Character Handling
Failure in any step causes the assertion to evaluate to Undefined. Failure in any step causes the assertion to evaluate to Undefined.
The character repertoire of this process is Unicode 3.2 [Unicode]. The character repertoire of this process is Unicode 3.2 [Unicode].
Note that this six-step process specification is intended to described Note that this six-step process specification is intended to describe
expected matching behavior. Implementations are free use alternative expected matching behavior. Implementations are free to use
processes so long as the matching rule evaluation behavior provided is alternative processes so long as the matching rule evaluation
consistent with the behavior described by this specification. behavior provided is consistent with the behavior described by this
specification.
2.1. Transcode 2.1. Transcode
Each non-Unicode string value is transcoded to Unicode. Each non-Unicode string value is transcoded to Unicode.
PrintableString [X.680] value are transcoded directly to Unicode. PrintableString [X.680] values are transcoded directly to Unicode.
UniversalString, UTF8String, and bmpString [X.680] values need not be UniversalString, UTF8String, and bmpString [X.680] values need not be
transcoded as they are Unicode-based strings (in the case of transcoded as they are Unicode-based strings (in the case of
bmpString, a subset of Unicode). bmpString, a subset of Unicode).
TeletexString [X.680] values are transcoded to Unicode. As there is TeletexString [X.680] values are transcoded to Unicode. As there is
no standard for mapping TeletexString values to Unicode, the mapping no standard for mapping TeletexString values to Unicode, the mapping
is left a local matter. is left a local matter.
For these and other reasons, use of TeletexString is NOT RECOMMENDED. For these and other reasons, use of TeletexString is NOT RECOMMENDED.
skipping to change at page 5, line 49 skipping to change at page 5, line 21
SOFT HYPHEN (U+00AD) and MONGOLIAN TODO SOFT HYPHEN (U+1806) code SOFT HYPHEN (U+00AD) and MONGOLIAN TODO SOFT HYPHEN (U+1806) code
points are mapped to nothing. COMBINING GRAPHEME JOINER (U+034F) and points are mapped to nothing. COMBINING GRAPHEME JOINER (U+034F) and
VARIATION SELECTORs (U+180B-180D, FF00-FE0F) code points are also VARIATION SELECTORs (U+180B-180D, FF00-FE0F) code points are also
mapped to nothing. The OBJECT REPLACEMENT CHARACTER (U+FFFC) is mapped to nothing. The OBJECT REPLACEMENT CHARACTER (U+FFFC) is
mapped to nothing. mapped to nothing.
CHARACTER TABULATION (U+0009), LINE FEED (LF) (U+000A), LINE CHARACTER TABULATION (U+0009), LINE FEED (LF) (U+000A), LINE
TABULATION (U+000B), FORM FEED (FF) (U+000C), CARRIAGE RETURN (CR) TABULATION (U+000B), FORM FEED (FF) (U+000C), CARRIAGE RETURN (CR)
(U+000D), and NEXT LINE (NEL) (U+0085) are mapped to SPACE (U+0020). (U+000D), and NEXT LINE (NEL) (U+0085) are mapped to SPACE (U+0020).
All other control code (e.g., Cc) points or code points with a control All other control code (e.g., Cc) points or code points with a
function (e.g., Cf) are mapped to nothing. The following is a control function (e.g., Cf) are mapped to nothing. The following is
complete list of these code points: U+0000-0008, 000E-001F, 007F-0084, a complete list of these code points: U+0000-0008, 000E-001F, 007F-
0086-009F, 06DD, 070F, 180E, 200C-200F, 202A-202E, 2060-2063, 0084, 0086-009F, 06DD, 070F, 180E, 200C-200F, 202A-202E, 2060-2063,
206A-206F, FEFF, FFF9-FFFB, 1D173-1D17A, E0001, E0020-E007F. 206A-206F, FEFF, FFF9-FFFB, 1D173-1D17A, E0001, E0020-E007F.
ZERO WIDTH SPACE (U+200B) is mapped to nothing. All other code points ZERO WIDTH SPACE (U+200B) is mapped to nothing. All other code
with Separator (space, line, or paragraph) property (e.g, Zs, Zl, or points with Separator (space, line, or paragraph) property (e.g., Zs,
Zp) are mapped to SPACE (U+0020). The following is a complete list of Zl, or Zp) are mapped to SPACE (U+0020). The following is a complete
these code points: U+0020, 00A0, 1680, 2000-200A, 2028-2029, 202F, list of these code points: U+0020, 00A0, 1680, 2000-200A, 2028-2029,
205F, 3000. 202F, 205F, 3000.
For case ignore, numeric, and stored prefix string matching rules, For case ignore, numeric, and stored prefix string matching rules,
characters are case folded per B.2 of [RFC3454]. characters are case folded per B.2 of [RFC3454].
The output is the mapped string. The output is the mapped string.
2.3. Normalize 2.3. Normalize
The input string is be normalized to Unicode Form KC (compatibility The input string is to be normalized to Unicode Form KC
composed) as described in [UAX15]. The output is the normalized (compatibility composed) as described in [UAX15]. The output is the
string. normalized string.
2.4. Prohibit 2.4. Prohibit
All Unassigned code points are prohibited. Unassigned code points are All Unassigned code points are prohibited. Unassigned code points
listed in Table A.1 of [RFC3454]. are listed in Table A.1 of [RFC3454].
Characters which, per Section 5.8 of [Stringprep], change display Characters that, per Section 5.8 of [RFC3454], change display
properties or are deprecated are prohibited. These characters are are properties or are deprecated are prohibited. These characters are
listed in Table C.8 of [RFC3454]. listed in Table C.8 of [RFC3454].
Private Use code points are prohibited. These characters are listed Private Use code points are prohibited. These characters are listed
in Table C.3 of [RFC3454]. in Table C.3 of [RFC3454].
All non-character code points are prohibited. These code points are All non-character code points are prohibited. These code points are
listed in Table C.4 of [RFC3454]. listed in Table C.4 of [RFC3454].
Surrogate codes are prohibited. These characters are listed in Table Surrogate codes are prohibited. These characters are listed in Table
C.5 of [RFC3454]. C.5 of [RFC3454].
The REPLACEMENT CHARACTER (U+FFFD) code point is prohibited. The REPLACEMENT CHARACTER (U+FFFD) code point is prohibited.
The step fails if the input string contains any prohibited code point. The step fails if the input string contains any prohibited code
Otherwise, the output is the input string. point. Otherwise, the output is the input string.
2.5. Check bidi 2.5. Check bidi
Bidirectional characters are ignored. Bidirectional characters are ignored.
2.6. Insignificant Character Handling 2.6. Insignificant Character Handling
In this step, the string is modified to ensure proper handling of In this step, the string is modified to ensure proper handling of
characters insignificant to the matching rule. This modification characters insignificant to the matching rule. This modification
differs from matching rule to matching rule. differs from matching rule to matching rule.
Section 2.6.1 applies to case ignore and exact string matching. Section 2.6.1 applies to case ignore and exact string matching.
Section 2.6.2 applies to numericString matching. Section 2.6.2 applies to numericString matching.
Section 2.6.3 applies to telephoneNumber matching. Section 2.6.3 applies to telephoneNumber matching.
2.6.1. Insignificant Space Handling 2.6.1. Insignificant Space Handling
For the purposes of this section, a space is defined to be the SPACE For the purposes of this section, a space is defined to be the SPACE
(U+0020) code point followed by no combining marks. (U+0020) code point followed by no combining marks.
NOTE - The previous steps ensure that the string cannot contain any NOTE - The previous steps ensure that the string cannot contain
code points in the separator class, other than SPACE (U+0020). any code points in the separator class, other than SPACE
(U+0020).
If the input string contains at least one non-space character, then For input strings that are attribute values or non-substring
the string is modified such that the string starts with exactly one assertion values: If the input string contains no non-space
space character, ends with exactly one SPACE character, and that any character, then the output is exactly two SPACEs. Otherwise (the
inner (non-empty) sequence of space characters is replaced with input string contains at least one non-space character), the string
exactly two SPACE characters. For instance, the input strings is modified such that the string starts with exactly one space
"foo<SPACE>bar<SPACE><SPACE>", results in the output character, ends with exactly one SPACE character, and any inner
(non-empty) sequence of space characters is replaced with exactly two
SPACE characters. For instance, the input strings
"foo<SPACE>bar<SPACE><SPACE>", result in the output
"<SPACE>foo<SPACE><SPACE>bar<SPACE>". "<SPACE>foo<SPACE><SPACE>bar<SPACE>".
Otherwise, if the string being prepared is an initial, any, or final For input strings that are substring assertion values: If the string
substring, then the output string is exactly one SPACE character, else being prepared contains no non-space characters, then the output
the output string is exactly two SPACEs. string is exactly one SPACE. Otherwise, the following steps are
taken:
- If the input string is an initial substring, it is modified to
start with exactly one SPACE character;
- If the input string is an initial or an any substring that ends in
one or more space characters, it is modified to end with exactly
one SPACE character;
- If the input string is an any or a final substring that starts in
one or more space characters, it is modified to start with exactly
one SPACE character; and
- If the input string is a final substring, it is modified to end
with exactly one SPACE character.
For instance, for the input string "foo<SPACE>bar<SPACE><SPACE>" as
an initial substring, the output would be
"<SPACE>foo<SPACE><SPACE>bar<SPACE>". As an any or final substring,
the same input would result in "foo<SPACE>bar<SPACE>".
Appendix B discusses the rationale for the behavior. Appendix B discusses the rationale for the behavior.
2.6.2. numericString Insignificant Character Handling 2.6.2. numericString Insignificant Character Handling
For the purposes of this section, a space is defined to be the SPACE For the purposes of this section, a space is defined to be the SPACE
(U+0020) code point followed by no combining marks. (U+0020) code point followed by no combining marks.
All spaces are regarded as insignificant and are to be removed. All spaces are regarded as insignificant and are to be removed.
skipping to change at page 8, line 13 skipping to change at page 7, line 49
"<SPACE><SPACE>123<SPACE><SPACE>456<SPACE><SPACE>" "<SPACE><SPACE>123<SPACE><SPACE>456<SPACE><SPACE>"
would result in the output string: would result in the output string:
"123456" "123456"
and the Form KC string: and the Form KC string:
"<SPACE><SPACE><SPACE>" "<SPACE><SPACE><SPACE>"
would result in the output string: would result in the output string:
"" (an empty string). "" (an empty string).
2.6.3. telephoneNumber Insignificant Character Handling 2.6.3. telephoneNumber Insignificant Character Handling
For the purposes of this section, a hyphen is defined to be For the purposes of this section, a hyphen is defined to be a
HYPHEN-MINUS (U+002D), ARMENIAN HYPHEN (U+058A), HYPHEN (U+2010), HYPHEN-MINUS (U+002D), ARMENIAN HYPHEN (U+058A), HYPHEN (U+2010),
NON-BREAKING HYPHEN (U+2011), MINUS SIGN (U+2212), SMALL HYPHEN-MINUS NON-BREAKING HYPHEN (U+2011), MINUS SIGN (U+2212), SMALL HYPHEN-MINUS
(U+FE63), or FULLWIDTH HYPHEN-MINUS (U+FF0D) code point followed by no (U+FE63), or FULLWIDTH HYPHEN-MINUS (U+FF0D) code point followed by
combining marks and a space is defined to be the SPACE (U+0020) code no combining marks and a space is defined to be the SPACE (U+0020)
point followed by no combining marks. code point followed by no combining marks.
All hyphens and spaces are considered insignificant and are to be All hyphens and spaces are considered insignificant and are to be
removed. removed.
For example, removal of hyphens and spaces from the Form KC string: For example, removal of hyphens and spaces from the Form KC string:
"<SPACE><HYPHEN>123<SPACE><SPACE>456<SPACE><HYPHEN>" "<SPACE><HYPHEN>123<SPACE><SPACE>456<SPACE><HYPHEN>"
would result in the output string: would result in the output string:
"123456" "123456"
and the Form KC string: and the Form KC string:
"<HYPHEN><HYPHEN><HYPHEN>" "<HYPHEN><HYPHEN><HYPHEN>"
would result in the (empty) output string: would result in the (empty) output string:
"". "".
3. Security Considerations 3. Security Considerations
"Preparation for International Strings ('stringprep')" [RFC3454] "Preparation of Internationalized Strings ("stringprep")" [RFC3454]
security considerations generally apply to the algorithms described security considerations generally apply to the algorithms described
here. here.
4. Acknowledgments 4. Acknowledgements
The approach used in this document is based upon design principles and The approach used in this document is based upon design principles
algorithms described in "Preparation of Internationalized Strings and algorithms described in "Preparation of Internationalized Strings
('stringprep')" [RFC3454] by Paul Hoffman and Marc Blanchet. Some ('stringprep')" [RFC3454] by Paul Hoffman and Marc Blanchet. Some
additional guidance was drawn from Unicode Technical Standards, additional guidance was drawn from Unicode Technical Standards,
Technical Reports, and Notes. Technical Reports, and Notes.
This document is a product of the IETF LDAP Revision (LDAPBIS) Working This document is a product of the IETF LDAP Revision (LDAPBIS)
Group. Working Group.
5. Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
Email: Kurt@OpenLDAP.org
6. References
[[Note to the RFC Editor: please replace the citation tags used in 5. References
referencing Internet-Drafts with tags of the form RFCnnnn where
possible.]]
6.1. Normative References 5.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14 (also RFC 2119), March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3454] Hoffman, P. and M. Blanchet, "Preparation of [RFC3454] Hoffman, P. and M. Blanchet, "Preparation of
Internationalized Strings ('stringprep')", RFC 3454, Internationalized Strings ("stringprep")", RFC 3454,
December 2002. December 2002.
[Roadmap] Zeilenga, K. (editor), "LDAP: Technical Specification [RFC4510] Zeilenga, K., "Lightweight Directory Access Protocol
Road Map", draft-ietf-ldapbis-roadmap-xx.txt, a work in (LDAP): Technical Specification Road Map", RFC 4510,
progress. June 2006.
[Syntaxes] Legg, S. (editor), "LDAP: Syntaxes and Matching Rules", [RFC4517] Legg, S., Ed., "Lightweight Directory Access Protocol
draft-ietf-ldapbis-syntaxes-xx.txt, a work in progress. (LDAP): Syntaxes and Matching Rules", RFC 4517, June
2006.
[Unicode] The Unicode Consortium, "The Unicode Standard, Version [Unicode] The Unicode Consortium, "The Unicode Standard, Version
3.2.0" is defined by "The Unicode Standard, Version 3.0" 3.2.0" is defined by "The Unicode Standard, Version
(Reading, MA, Addison-Wesley, 2000. ISBN 0-201-61633-5), 3.0" (Reading, MA, Addison-Wesley, 2000. ISBN 0-201-
as amended by the "Unicode Standard Annex #27: Unicode 61633-5), as amended by the "Unicode Standard Annex
3.1" (http://www.unicode.org/reports/tr27/) and by the #27: Unicode 3.1"
(http://www.unicode.org/reports/tr27/) and by the
"Unicode Standard Annex #28: Unicode 3.2" "Unicode Standard Annex #28: Unicode 3.2"
(http://www.unicode.org/reports/tr28/). (http://www.unicode.org/reports/tr28/).
[UAX15] Davis, M. and M. Duerst, "Unicode Standard Annex #15: [UAX15] Davis, M. and M. Duerst, "Unicode Standard Annex #15:
Unicode Normalization Forms, Version 3.2.0". Unicode Normalization Forms, Version 3.2.0".
<http://www.unicode.org/unicode/reports/tr15/tr15-22.html>, <http://www.unicode.org/unicode/reports/tr15/tr15-
March 2002. 22.html>, March 2002.
[X.680] International Telecommunication Union - [X.680] International Telecommunication Union -
Telecommunication Standardization Sector, "Abstract Telecommunication Standardization Sector, "Abstract
Syntax Notation One (ASN.1) - Specification of Basic Syntax Notation One (ASN.1) - Specification of Basic
Notation", X.680(2002) (also ISO/IEC 8824-1:2002). Notation", X.680(2002) (also ISO/IEC 8824-1:2002).
6.2. Informative References 5.2. Informative References
[X.500] International Telecommunication Union - [X.500] International Telecommunication Union -
Telecommunication Standardization Sector, "The Directory Telecommunication Standardization Sector, "The
-- Overview of concepts, models and services," Directory -- Overview of concepts, models and
X.500(1993) (also ISO/IEC 9594-1:1994). services," X.500(1993) (also ISO/IEC 9594-1:1994).
[X.501] International Telecommunication Union - [X.501] International Telecommunication Union -
Telecommunication Standardization Sector, "The Directory Telecommunication Standardization Sector, "The
-- Models," X.501(1993) (also ISO/IEC 9594-2:1994). Directory -- Models," X.501(1993) (also ISO/IEC 9594-
2:1994).
[X.520] International Telecommunication Union - [X.520] International Telecommunication Union -
Telecommunication Standardization Sector, "The Telecommunication Standardization Sector, "The
Directory: Selected Attribute Types", X.520(1993) (also Directory: Selected Attribute Types", X.520(1993) (also
ISO/IEC 9594-6:1994). ISO/IEC 9594-6:1994).
[Glossary] The Unicode Consortium, "Unicode Glossary", [Glossary] The Unicode Consortium, "Unicode Glossary",
<http://www.unicode.org/glossary/>. <http://www.unicode.org/glossary/>.
[CharModel] Whistler, K. and M. Davis, "Unicode Technical Report [CharModel] Whistler, K. and M. Davis, "Unicode Technical Report
#17, Character Encoding Model", UTR17, #17, Character Encoding Model", UTR17,
<http://www.unicode.org/unicode/reports/tr17/>, August <http://www.unicode.org/unicode/reports/tr17/>, August
2000. 2000.
[Filters] Smith, M. (editor), LDAPbis WG, "LDAP: String [RFC3377] Hodges, J. and R. Morgan, "Lightweight Directory Access
Representation of Search Filters", Protocol (v3): Technical Specification", RFC 3377,
draft-ietf-ldapbis-filter-xx.txt, a work in progress. September 2002.
[RFC4515] Smith, M., Ed. and T. Howes, "Lightweight Directory
Access Protocol (LDAP): String Representation of Search
Filters", RFC 4515, June 2006.
[XMATCH] Zeilenga, K., "Internationalized String Matching Rules [XMATCH] Zeilenga, K., "Internationalized String Matching Rules
for X.500", draft-zeilenga-ldapbis-strmatch-xx.txt, a for X.500", Work in Progress.
work in progress.
Appendix A. Combining Marks Appendix A. Combining Marks
This appendix is normative. This appendix is normative.
This table was derived from Unicode [Unicode] data This table was derived from Unicode [Unicode] data files; it lists
files, it lists all code points with the Mn, Mc, or Me all code points with the Mn, Mc, or Me properties. This table is to
properties. This table is to be considered definitive be considered definitive for the purposes of implementation of this
for the purposes of implementation of this
specification. specification.
0300-034F 0360-036F 0483-0486 0488-0489 0591-05A1 0300-034F 0360-036F 0483-0486 0488-0489 0591-05A1
05A3-05B9 05BB-05BC 05BF 05C1-05C2 05C4 064B-0655 0670 05A3-05B9 05BB-05BC 05BF 05C1-05C2 05C4 064B-0655 0670
06D6-06DC 06DE-06E4 06E7-06E8 06EA-06ED 0711 0730-074A 06D6-06DC 06DE-06E4 06E7-06E8 06EA-06ED 0711 0730-074A
07A6-07B0 0901-0903 093C 093E-094F 0951-0954 0962-0963 07A6-07B0 0901-0903 093C 093E-094F 0951-0954 0962-0963
0981-0983 09BC 09BE-09C4 09C7-09C8 09CB-09CD 09D7 0981-0983 09BC 09BE-09C4 09C7-09C8 09CB-09CD 09D7
09E2-09E3 0A02 0A3C 0A3E-0A42 0A47-0A48 0A4B-0A4D 09E2-09E3 0A02 0A3C 0A3E-0A42 0A47-0A48 0A4B-0A4D
0A70-0A71 0A81-0A83 0ABC 0ABE-0AC5 0AC7-0AC9 0ACB-0ACD 0A70-0A71 0A81-0A83 0ABC 0ABE-0AC5 0AC7-0AC9 0ACB-0ACD
0B01-0B03 0B3C 0B3E-0B43 0B47-0B48 0B4B-0B4D 0B56-0B57 0B01-0B03 0B3C 0B3E-0B43 0B47-0B48 0B4B-0B4D 0B56-0B57
skipping to change at page 11, line 25 skipping to change at page 11, line 39
0F99-0FBC 0FC6 102C-1032 1036-1039 1056-1059 1712-1714 0F99-0FBC 0FC6 102C-1032 1036-1039 1056-1059 1712-1714
1732-1734 1752-1753 1772-1773 17B4-17D3 180B-180D 18A9 1732-1734 1752-1753 1772-1773 17B4-17D3 180B-180D 18A9
20D0-20EA 302A-302F 3099-309A FB1E FE00-FE0F FE20-FE23 20D0-20EA 302A-302F 3099-309A FB1E FE00-FE0F FE20-FE23
1D165-1D169 1D16D-1D172 1D17B-1D182 1D185-1D18B 1D165-1D169 1D16D-1D172 1D17B-1D182 1D185-1D18B
1D1AA-1D1AD 1D1AA-1D1AD
Appendix B. Substrings Matching Appendix B. Substrings Matching
This appendix is non-normative. This appendix is non-normative.
In absence of substrings matching, the insignificant In the absence of substrings matching, the insignificant space
space handling for case ignore/exact matching could be handling for case ignore/exact matching could be simplified.
simplified. Specifically, the handling could be as Specifically, the handling could be to require that all sequences of
require all sequences of one or more spaces be replaced one or more spaces be replaced with one space and, if the string
with one space and, if string contains non-space contains non-space characters, removal of all leading spaces and
characters, removal of all all leading spaces and
trailing spaces. trailing spaces.
In the presence of substrings matching, this simplified In the presence of substrings matching, this simplified space
space handling would lead to unexpected and undesirable handling would lead to unexpected and undesirable matching behavior.
matching behavior. For instance: For instance:
1) (CN=foo\20*\20bar) would match the CN value "foobar" but not
"foo<SPACE>bar" nor "foo<SPACE><SPACE>bar"; 1) (CN=foo\20*\20bar) would match the CN value "foobar";
2) (CN=*\20foobar\20*) would match "foobar", but (CN=*\20*foobar*\20*) 2) (CN=*\20foobar\20*) would match "foobar", but
would not; (CN=*\20*foobar*\20*) would not.
3) (CN=foo\20*\20bar) would match "foo<SPACE>X<SPACE>bar" but not
"foo<SPACE><SPACE>bar".
Note to readers not familiar with LDAP substrings matching: the LDAP Note to readers not familiar with LDAP substrings matching: the LDAP
filter [Filters] assertion (CN=A*B*C) says "match any value (of the filter [RFC4515] assertion (CN=A*B*C) says to "match any value (of
attribute CN) which begins with A, contains B after A, ends with C the attribute CN) that begins with A, contains B after A, ends with C
where C is also after B." where C is also after B."
The first case illustrates that this simplified space handling would The first case illustrates that this simplified space handling would
cause leading and trailing spaces in substrings of the string to be cause leading and trailing spaces in substrings of the string to be
regarded as insignificant. However, only leading and trailing (as regarded as insignificant. However, only leading and trailing (as
well as multiple consecutive spaces) of the string (as a whole) are well as multiple consecutive spaces) of the string (as a whole) are
insignificant. insignificant.
The second case illustrates that this simplified space handling would The second case illustrates that this simplified space handling would
cause sub-partitioning failures. That is, if a prepared any substring cause sub-partitioning failures. That is, if a prepared any
matches a partition of the attribute value, then an assertion substring matches a partition of the attribute value, then an
constructed by subdividing that substring into multiple substrings assertion constructed by subdividing that substring into multiple
should also match. substrings should also match.
The third case illustrates that this simplified space handling causes In designing an appropriate approach for space handling for
another partitioning failure. Though both the initial or final substrings matching, one must study key aspects of X.500 case
strings match different portions of "foo<SPACE>X<SPACE>bar" with exact/ignore matching. X.520 [X.520] says:
neither matching the X portion, they don't match a string consisting
of the two matched portions less the unmatched X portion.
In designing an appropriate approach for space handling for substrings
matching, one must study key aspects of X.500 case exact/ignore
matching. X.520 [X.520] says:
The [substrings] rule returns TRUE if there is a partitioning of The [substrings] rule returns TRUE if there is a partitioning of
the attribute value (into portions) such that: the attribute value (into portions) such that:
- the specified substrings (initial, any, final) match different
portions of the value in the order of the strings sequence; - the specified substrings (initial, any, final) match
different portions of the value in the order of the strings
sequence;
- initial, if present, matches the first portion of the value; - initial, if present, matches the first portion of the value;
- final, if present, matches the last portion of the value; - final, if present, matches the last portion of the value;
- any, if present, matches some arbitrary portion of the value.
- any, if present, matches some arbitrary portion of the
value.
That is, the substrings assertion (CN=foo\20*\20bar) matches the That is, the substrings assertion (CN=foo\20*\20bar) matches the
attribute value "foo<SPACE><SPACE>bar" as the value can be partitioned attribute value "foo<SPACE><SPACE>bar" as the value can be
into the portions "foo<SPACE>" and "<SPACE>bar" meeting the above partitioned into the portions "foo<SPACE>" and "<SPACE>bar" meeting
requirements. the above requirements.
X.520 also says: X.520 also says:
[T]he following spaces are regarded as not significant: [T]he following spaces are regarded as not significant:
- leading spaces (i.e. those preceding the first character that is
not a space); - leading spaces (i.e., those preceding the first character
- trailing spaces (i.e. those following the last character that is that is not a space);
not a space);
- multiple consecutive spaces (these are taken as equivalent to a - trailing spaces (i.e., those following the last character
single space character). that is not a space);
- multiple consecutive spaces (these are taken as equivalent
to a single space character).
This statement applies to the assertion values and attribute values This statement applies to the assertion values and attribute values
as whole strings, and not individually to substrings of an assertion as whole strings, and not individually to substrings of an assertion
value. In particular, the statements should be taken to mean that value. In particular, the statements should be taken to mean that if
if an assertion value and attribute value match without any an assertion value and attribute value match without any
consideration to insignificant characters, then that assertion value consideration to insignificant characters, then that assertion value
should also match any attribute value which differs only by inclusion should also match any attribute value that differs only by inclusion
or removal of insignificant characters. nor removal of insignificant characters.
Hence, the assertion (CN=foo\20*\20bar) matches Hence the assertion (CN=foo\20*\20bar) matches
"foo<SPACE><SPACE><SPACE>bar" and "foo<SPACE>bar" as these values "foo<SPACE><SPACE><SPACE>bar" and "foo<SPACE>bar" as these values
only differ from "foo<SPACE><SPACE>bar" by the inclusion or removal only differ from "foo<SPACE><SPACE>bar" by the inclusion or removal
of insignificant spaces. of insignificant spaces.
Astute readers of this text will also note that there are special Astute readers of this text will also note that there are special
cases where the specified space handling does not ignore spaces cases where the specified space handling does not ignore spaces that
which could be considered insignificant. For instance, the assertion could be considered insignificant. For instance, the assertion
(CN=\20*\20*\20) does not match "<SPACE><SPACE><SPACE>" (CN=\20*\20*\20) does not match "<SPACE><SPACE><SPACE>"
(insignificant spaces present in value) nor " " (insignificant (insignificant spaces present in value) or " " (insignificant spaces
spaces not present in value). However, as these cases have no not present in value). However, as these cases have no practical
practical application that cannot be met by simple assertions, e.g. application that cannot be met by simple assertions, e.g., (cn=\20),
(cn=\20), and this minor anomaly can only be fully addressed by a and this minor anomaly can only be fully addressed by a preparation
preparation algorithm to be used in conjunction with algorithm to be used in conjunction with character-by-character
character-by-character partitioning and matching, the anomaly is partitioning and matching, the anomaly is considered acceptable.
considered acceptable.
Intellectual Property Rights Author's Address
Kurt D. Zeilenga
OpenLDAP Foundation
EMail: Kurt@OpenLDAP.org
Full Copyright Statement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed Intellectual Property Rights or other rights that might be claimed to
to pertain to the implementation or use of the technology described pertain to the implementation or use of the technology described in
in this document or the extent to which any license under such this document or the extent to which any license under such rights
rights might or might not be available; nor does it represent that might or might not be available; nor does it represent that it has
it has made any independent effort to identify any such rights. made any independent effort to identify any such rights. Information
Information on the procedures with respect to rights in RFC documents on the procedures with respect to rights in RFC documents can be
can be found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use attempt made to obtain a general license or permission for the use of
of such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository specification can be obtained from the IETF on-line IPR repository at
at http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Full Copyright Acknowledgement
Copyright (C) The Internet Society (2006).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an Funding for the RFC Editor function is provided by the IETF
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE Administrative Support Activity (IASA).
REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE
INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 End of changes. 74 change blocks. 
258 lines changed or deleted 274 lines changed or added

This html diff was produced by rfcdiff 1.32. The latest version is available from http://www.levkowetz.com/ietf/tools/rfcdiff/