summaryrefslogtreecommitdiff
path: root/source4/ldap_server/devdocs/rfc4522.txt
blob: 11156a07f10eb02317718c5bb197a5009a52c767 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451






Network Working Group                                            S. Legg
Request for Comments: 4522                                       eB2Bcom
Category: Standards Track                                      June 2006


             Lightweight Directory Access Protocol (LDAP):
                       The Binary Encoding Option

Status of This Memo

   This document specifies an Internet standards track protocol for the
   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 Notice

   Copyright (C) The Internet Society (2006).

Abstract

   Each attribute stored in a Lightweight Directory Access Protocol
   (LDAP) directory has a defined syntax (i.e., data type).  A syntax
   definition specifies how attribute values conforming to the syntax
   are normally represented when transferred in LDAP operations.  This
   representation is referred to as the LDAP-specific encoding to
   distinguish it from other methods of encoding attribute values.  This
   document defines an attribute option, the binary option, that can be
   used to specify that the associated attribute values are instead
   encoded according to the Basic Encoding Rules (BER) used by X.500
   directories.

Table of Contents

   1. Introduction ....................................................2
   2. Conventions .....................................................2
   3. The Binary Option ...............................................2
   4. Syntaxes Requiring Binary Transfer ..............................3
   5. Attributes Returned in a Search .................................4
   6. All User Attributes .............................................4
   7. Conflicting Requests ............................................5
   8. Security Considerations .........................................5
   9. IANA Considerations .............................................5
   10. References .....................................................5
      10.1. Normative References ......................................5
      10.2. Informative References ....................................6




Legg                        Standards Track                     [Page 1]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


1.  Introduction

   Each attribute stored in a Lightweight Directory Access Protocol
   (LDAP) directory [RFC4510] has a defined syntax (i.e., data type)
   which constrains the structure and format of its values.

   The description of each syntax [RFC4517] specifies how attribute or
   assertion values [RFC4512] conforming to the syntax are normally
   represented when transferred in LDAP operations [RFC4511].  This
   representation is referred to as the LDAP-specific encoding to
   distinguish it from other methods of encoding attribute values.

   This document defines an attribute option, the binary option, which
   can be used in an attribute description [RFC4512] in an LDAP
   operation to specify that the associated attribute values or
   assertion values are, or are requested to be, encoded according to
   the Basic Encoding Rules (BER) [BER] as used by X.500 [X.500]
   directories, instead of the usual LDAP-specific encoding.

   The binary option was originally defined in RFC 2251 [RFC2251].  The
   LDAP technical specification [RFC4510] has obsoleted the previously
   defined LDAP technical specification [RFC3377], which included RFC
   2251.  The binary option was not included in the revised LDAP
   technical specification for a variety of reasons including
   implementation inconsistencies.  No attempt is made here to resolve
   the known inconsistencies.

   This document reintroduces the binary option for use with certain
   attribute syntaxes, such as certificate syntax [RFC4523], that
   specifically require it.  No attempt has been made to address use of
   the binary option with attributes of syntaxes that do not require its
   use.  Unless addressed in a future specification, this use is to be
   avoided.

2.  Conventions

   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, RFC 2119
   [BCP14].

3.  The Binary Option

   The binary option is indicated with the attribute option string
   "binary" in an attribute description.  Note that, like all attribute
   options, the string representing the binary option is case
   insensitive.




Legg                        Standards Track                     [Page 2]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


   Where the binary option is present in an attribute description, the
   associated attribute values or assertion values MUST be BER encoded
   (otherwise the values are encoded according to the LDAP-specific
   encoding [RFC4517] for the attribute's syntax).  Note that it is
   possible for a syntax to be defined such that its LDAP-specific
   encoding is exactly the same as its BER encoding.

   In terms of the protocol [RFC4511], the binary option specifies that
   the contents octets of the associated AttributeValue or
   AssertionValue OCTET STRING are a complete BER encoding of the
   relevant value.

   The binary option is not a tagging option [RFC4512], so the presence
   of the binary option does not specify an attribute subtype.  An
   attribute description containing the binary option references exactly
   the same attribute as the attribute description without the binary
   option.  The supertype/subtype relationships of attributes with
   tagging options are not altered in any way by the presence or absence
   of the binary option.

   An attribute description SHALL be treated as unrecognized if it
   contains the binary option and the syntax of the attribute does not
   have an associated ASN.1 type [RFC4517], or the BER encoding of
   values of that type is not supported.

   The presence or absence of the binary option only affects the
   transfer of attribute and assertion values in the protocol; servers
   store any particular attribute value in a format of their choosing.

4.  Syntaxes Requiring Binary Transfer

   The attribute values of certain attribute syntaxes are defined
   without an LDAP-specific encoding and are required to be transferred
   in the BER-encoded form.  For the purposes of this document, these
   syntaxes are said to have a binary transfer requirement.  The
   certificate, certificate list, certificate pair, and supported
   algorithm syntaxes [RFC4523] are examples of syntaxes with a binary
   transfer requirement.  These syntaxes also have an additional
   requirement that the exact BER encoding must be preserved.  Note that
   this is a property of the syntaxes themselves, and not a property of
   the binary option.  In the absence of this requirement, LDAP clients
   would need to re-encode values using the Distinguished Encoding Rules
   (DER).








Legg                        Standards Track                     [Page 3]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


5.  Attributes Returned in a Search

   An LDAP search request [RFC4511] contains a list of the attributes
   (the requested attributes list) to be returned from each entry
   matching the search filter.  An attribute description in the
   requested attributes list also implicitly requests all subtypes of
   the attribute type in the attribute description, whether through
   attribute subtyping or attribute tagging option subtyping [RFC4512].

   The requested attributes list MAY contain attribute descriptions with
   the binary option, but MUST NOT contain two attribute descriptions
   with the same attribute type and the same tagging options (even if
   only one of them has the binary option).  The binary option in an
   attribute description in the requested attributes list implicitly
   applies to all the subtypes of the attribute type in the attribute
   description (however, see Section 7).

   Attributes of a syntax with the binary transfer requirement, if
   returned, SHALL be returned in the binary form (i.e., with the binary
   option in the attribute description and the associated attribute
   values BER encoded) regardless of whether the binary option was
   present in the request (for the attribute or for one of its
   supertypes).

   Attributes of a syntax without the binary transfer requirement, if
   returned, SHOULD be returned in the form explicitly requested.  That
   is, if the attribute description in the requested attributes list
   contains the binary option, then the corresponding attribute in the
   result SHOULD be in the binary form.  If the attribute description in
   the request does not contain the binary option, then the
   corresponding attribute in the result SHOULD NOT be in the binary
   form.  A server MAY omit an attribute from the result if it does not
   support the requested encoding.

   Regardless of the encoding chosen, a particular attribute value is
   returned at most once.

6.  All User Attributes

   If the list of attributes in a search request is empty or contains
   the special attribute description string "*", then all user
   attributes are requested to be returned.

   Attributes of a syntax with the binary transfer requirement, if
   returned, SHALL be returned in the binary form.






Legg                        Standards Track                     [Page 4]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


   Attributes of a syntax without the binary transfer requirement and
   having a defined LDAP-specific encoding SHOULD NOT be returned in the
   binary form.

   Attributes of a syntax without the binary transfer requirement and
   without a defined LDAP-specific encoding may be returned in the
   binary form or omitted from the result.

7.  Conflicting Requests

   A particular attribute could be explicitly requested by an attribute
   description and/or implicitly requested by the attribute descriptions
   of one or more of its supertypes, or by the special attribute
   description string "*".  If the binary option is present in at least
   one, but not all, of these attribute descriptions then the effect of
   the request with respect to binary transfer is implementation
   defined.

8.  Security Considerations

   When interpreting security-sensitive fields, and in particular fields
   used to grant or deny access, implementations MUST ensure that any
   matching rule comparisons are done on the underlying abstract value,
   regardless of the particular encoding used.

9.  IANA Considerations

   The Internet Assigned Numbers Authority (IANA) has updated the LDAP
   attribute description option registry [BCP64] as indicated by the
   following template:

      Subject:
        Request for LDAP Attribute Description Option Registration
      Option Name: binary
      Family of Options: NO
      Person & email address to contact for further information:
        Steven Legg <steven.legg@eb2bcom.com>
      Specification: RFC 4522
      Author/Change Controller: IESG

10.  References

10.1.  Normative References

   [BCP14]    Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.





Legg                        Standards Track                     [Page 5]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


   [BCP64]    Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
              Considerations for the Lightweight Directory Access
              Protocol (LDAP)", BCP 64, RFC 4520, June 2006.

   [RFC4510]  Zeilenga, K., Ed., "Lightweight Directory Access Protocol
              (LDAP): Technical Specification Road Map", RFC RFC 4510,
              June 2006.

   [RFC4511]  Sermersheim, J., "Lightweight Directory Access Protocol
              (LDAP): The Protocol", RFC 4511, June 2006.

   [RFC4512]  Zeilenga, K., "Lightweight Directory Access Protocol
              (LDAP): Directory Information Models", RFC 4512, June
              2006.

   [RFC4517]  Legg, S., Ed., "Lightweight Directory Access Protocol
              (LDAP):  Syntaxes and Matching Rules", RFC 4517, June
              2006.

   [RFC4523]  Zeilenga, K., "Lightweight Directory Access Protocol
              (LDAP) Schema Definitions for X.509 Certificates", RFC
              4523, June 2006.

   [BER]      ITU-T Recommendation X.690 (07/02) | ISO/IEC 8825-1,
              Information Technology - ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules
              (DER).

10.2.  Informative References

   [RFC2251]  Wahl, M., Howes, T., and S. Kille, "Lightweight Directory
              Access Protocol (v3)", RFC 2251, December 1997.

   [RFC3377]  Hodges, J. and R. Morgan, "Lightweight Directory Access
              Protocol (v3): Technical Specification", RFC 3377,
              September 2002.

   [X.500]    ITU-T Recommendation X.500 (02/01) | ISO/IEC 9594-1:2001,
              Information technology - Open Systems Interconnection -
              The Directory:  Overview of concepts, models and services










Legg                        Standards Track                     [Page 6]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


Author's Address

   Dr. Steven Legg
   eB2Bcom
   Suite 3, Woodhouse Corporate Centre
   935 Station Street
   Box Hill North, Victoria 3129
   AUSTRALIA

   Phone: +61 3 9896 7830
   Fax:   +61 3 9896 7801
   EMail: steven.legg@eb2bcom.com







































Legg                        Standards Track                     [Page 7]

RFC 4522            LDAP: The Binary Encoding Option           June 2006


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
   Intellectual Property Rights or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; nor does it represent that it has
   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
   assurances of licenses to be made available, or the result of an
   attempt made to obtain a general license or permission for the use of
   such proprietary rights by implementers or users of this
   specification can be obtained from the IETF on-line IPR repository at
   http://www.ietf.org/ipr.

   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights that may cover technology that may be required to implement
   this standard.  Please address the information to the IETF at
   ietf-ipr@ietf.org.

Acknowledgement

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).







Legg                        Standards Track                     [Page 8]