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Re: ABNF tweak for draft-zeilenga-ldapbis-rfc2253-02
Hi there,
It might be a good idea to not rely too heavily on
everything that may appear in RFC 2849, but to consider
using the most current materials from the unicode site,
and to rely on the precise definitions of the restricted
character string types found in the ASN.1 standards. See
www.unicode.org/unicode/uni2errata/UTF-8_Corrigendum.html
for a discussion relevant to the notion of the 5 and 6
byte sequences listed below.
Note that the changes described at this link are very much
in line with the long held notion in ASN.1 of string types
whose values are said to be "restricted". Much is simply
not allowed by the ASN.1 standards for such types (BOMs,
escapes to other character sets) for the sole purpose of
promoting secure interworking between applications.
Phil
----
Phillip H. Griffin Griffin Consulting
http://asn-1.com Secure ASN.1 Design & Implementation
+1-919-832-7008 1625 Glenwood Avenue, Five Points
+1-919-832-7390 [fax] Raleigh, North Carolina 27608 USA
------------------------------------------------------------
"Kurt D. Zeilenga" wrote:
>
> At 07:47 PM 12/18/00 -0500, rmoats@coreon.net wrote:
> >Ok, I'll bite... what does ASCII have to do with this other
> >than extending the last range to FF...
>
> Extending the range to FF is not sufficient. The ISO-10646-1
> character code range, IIRC, is 0x000000 - 0x7FFFFFFF. When
> presented as UTF-8, each character spans from 1 to 6 octets
> (derived from RFC2849):
>
> UTF8-CHAR = ASCII / UTF8-2 / UTF8-3 /
> UTF8-4 / UTF8-5 / UTF8-6
> UTF8-1 = %x80-BF
> UTF8-2 = %xC0-DF UTF8-1
> UTF8-3 = %xE0-EF 2UTF8-1
> UTF8-4 = %xF0-F7 3UTF8-1
> UTF8-5 = %xF8-FB 4UTF8-1
> UTF8-6 = %xFC-FD 5UTF8-1
> ASCII = %x00-7F
>
> Your original suggestion would limit escaping to only ASCII
> characters. With the range extension, the escaping would
> apply to the first octet of the character, not to the whole
> character.
>
> Kurt
>
> >Ryan
> >
> >---- Original message ----
> >>Date: Mon, 18 Dec 2000 16:03:33 -0800
> >>From: "Kurt D. Zeilenga" <Kurt@OpenLDAP.org>
> >>Subject: Re: ABNF tweak for draft-zeilenga-ldapbis-rfc2253-02
> >>To: "Ryan Moats" <rmoats@coreon.net>
> >>Cc: <ietf-ldapbis@OpenLDAP.org>
> >>
> >>At 11:33 AM 12/10/00 -0600, Ryan Moats wrote:
> >>>I'd suggest
> >>>
> >>> quotechar = %x00-%x21 / %x23-%x5B / %x5D-7F ; any
> >character except "\" or
> >>>QUOTATION
> >>
> >>Note that any character is not restricted to ASCII.
> >>
> >>Kurt
> >>