RE: Syntax Survey Version 2

["Steven Legg" <steven.legg@adacel.com.au>]

Chris,

Chris Ridd wrote:
> Steven Legg <steven.legg@adacel.com.au> wrote:
> >             OID: 1.3.6.1.4.1.1466.115.121.1.18
> >   RFC 2252 NAME: DL Submit Permission
> > STRING ENCODING: Section 2.34, RFC 1778
> >      ASN.1 TYPE: DLSubmitPermission, ...
> >     CONFORMANCE: unspecified
> >
> > I haven't got the relevant X.400 standard (yet) to confirm
> the reference
> > for the ASN.1 type.
>
> X.402(1992) has this:
>
> DLSubmitPermission ::= CHOICE {
>     individual      [0] ORName,
>     member-of-dl    [1] ORName,
>     pattern-match   [2] ORNamePattern,
>     member-of-group [3] Name }
>
> Incidentally, X.402 actually defines an OID for this syntax:
>
> id-as-mhs-dl-submit-permission ID ::= { 2 6 5 3 0 }
>
> Incidentally what is the purpose of the 'LDAP OID' for this
> syntax? Does it
> merely define the LDAP string representation of these values?
> If so, why
> define LDAP OIDs for the syntaxes like ACI item that don't
> have a string
> representation? Or is that a bug?

The LDAP syntax OID is meant to be more general than just identifying
a specific string encoding. It is meant to indicate what sort of thing
an attribute type is representing, for presentation and other purposes.
For example, it is useful to know that an attribute is holding X.509
Certificates even though there is no string encoding for certificates.
LDAP clients and servers can be made extensible rather than being
hard-wired to perform certain actions on certain known attribute types.

>
> >             OID: 1.3.6.1.4.1.1466.115.121.1.33
> >   RFC 2252 NAME: MHS OR Address
> > STRING ENCODING: Section 4.1, RFC 2156
> >                : RFC 2252 references the obsolete RFC 1327
> >      ASN.1 TYPE: ORAddress, ...
> >     CONFORMANCE: SHOULD, Section 6, RFC 2252
> >
> > I haven't got the relevant X.400 standard (yet) to confirm
> the reference
> > for the ASN.1 type.
>
> The ASN.1 definition for ORAddress (and ORName, see
> DLSubmitPermission) is
> found in X.411(1992). It's a bit too big to include here :-)
>
> It also has a syntax OID specified for it:
>
> id-as-mhs-or-address ID ::= { 2 6 5 3 1 }

This is a different beast to the LDAP syntax OID. The 1988 edition of X.500
defined attribute syntaxes, which comprised an ASN.1 type and the associated
matching semantics, each with a distinct OID. The 1993 edition of X.500
deprecated the attribute syntaxes from the 1988 edition and introduced
matching rules to replace them. The 1993 attribute definitions explicitly
reference equality, ordering and substrings matching rules to define
the intended matching semantics. The LDAP syntax OID is just an alternative
means of identifying the data type (ASN.1 type) of an attribute. No matching
semantics are implied.

Since X.411(1992) is referencing 1988 X.500 concepts we will want to refer
to a later edition in the successors to RFC 2252 and 2256, if the X.400
syntaxes don't get thrown out. In the meantime, I'll put your references
into the syntax survey.

Thanks,
Steven

>
> Cheers,
>
> Chris
>