RFC 4511, "Lightweight Directory Access Protocol (LDAP): The Protocol", June 2006

Errata ID: 5292
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: Markus Ansmann
Date Reported: 2018-03-21

Section 4.5.1/Appx.B says:

Filter ::= CHOICE {
and [0] SET SIZE (1..MAX) OF filter Filter,
or [1] SET SIZE (1..MAX) OF filter Filter,
not [2] Filter,

It should say:

Filter ::= CHOICE {
and [0] SET SIZE (1..MAX) OF filter Filter,
or [1] SET SIZE (1..MAX) OF filter Filter,
not [2] EXPLICIT Filter,

Notes:

As currently written, the specification requires IMPLICIT tagging for the not-filter. This, according to ITU-T X.690, Section 8.14.3, Example "Type5", requires the [2]-tag of the not-filter to overwrite the tag of the negated filter, making reliable identification of the type of the negated filter impossible. Thus, the definition of the not-filter needs to specify EXPLICIT tagging. Alternatively, the filter could be specified as

not [2] SEQUENCE { filter Filter },

or (to match the definition of "and" and "or")

not [2] SET SIZE (1..1) OF filter Filter,

This applies to both, Section 4.5.1 and Appendix B.

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