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Re: Characters in DN
OK. I have modified the code to be more conformant with draft-ietf-ldapbis-dn-05.txt. Now, the '=' character is not escaped in the normalized string, and '#' is only escaped if it is the first character in an attribute value. I also added a note at the beginning of servers/slapd/dn.c listing the functions in that module that I wrote and specifying that that code is in the public domain (i.e., it is not subject to copyright).
A new patch file is now available for download from http://csrc.nist.gov/pki/testing/openLDAP_contrib.html.
If you have any other suggestions for changes to the code, please let me know.
At 08:28 AM 7/12/01 +0200, Pierangelo Masarati wrote:
>"David A. Cooper" wrote:
> > > I have only one question. You treat '=' and '#' as
> > > characters that need to be escaped. While rfc 2253
> > > says implementations may escape other characters,
> > > it doesn't require them to be treated as special except
> > > in type/value separation (=) and beginning of string (#).
> > > I think you should handle them differently.
> > In my code, I compromised. The dn_validate/dn_normalize functions will
> > take as input DNs that contain unescaped (=)'s and (#)'s, but in the
> > normalized form they are escaped. So for example, the input "cn= ===###" is
> > accepted, but the output is "CN=\=\=\=\#\#\#".
> > I see that the BNF in draft-ietf-ldapbis-dn-05.txt is different. It defines
> > stringchar as:
> > stringchar = <any UTF-8 character (can be multiple octets)
> > except one of escaped or ESC>
> > escaped = "," / "+" / """ / "<" / ">" / ";"
> > So, while the BNF of draft-ietf-ldapbis-dn-05.txt is clear that '=' and '#'
> > do not need to be escaped, the BNF in RFC 2253 suggests otherwise (in
> > contradiction to the text of RFC 2253).
>As Kurt said, we'd better stick with draft-ietf-ldapbis-dn-05.txt,
>so your code is OK although it may be improved to obtain a strict
>adherence to draft-ietf-ldapbis-dn-05.txt, which is preferable.
> > To some degree, the issue is somewhat academic though. The code will accept
> > DNs with unescaped '=' and '#' and the normalized versions of the DNs, with
> > the '=' and '#' are definitely compliant with RFC 2253. The only question is
> > whether a few bytes are being wasted by including escape characters where
> > they may not be absolutely necessary.
>We're not talking about wasting chars :)
> > However, if people feel that this is important, I'll look into changing the
> > code to avoid escaping '=' and '#' (unless the '#' is the first character in
> > the string).
> > > Someone who's directly involved in unicode stuff
> > > should check the UTF part before anything is added.
> > > I'm totally stuck with it at present (see why we need
> > > ITS?)
> > That would be helpful. Originally, Stig Venås incorporated unicode
> > normalization into the dnNormalize function by making a call to
> > UTF8normalize. I used the UTF8normalize function as a guide in order to
> > directly incorporate calls to uccanondecomp and uccanoncomp into my code. I
> > tried it out with a few simple examples, and the code seems to be handling
> > unicode normalization properly, but it would certainly be helpful to have
> > others test it out as well.
>If there's no objections, I'll incorporate your code under
>#ifdef to ease testing by other users.Thanks for contributing.
>Another note: I guess OpenLDAP needs a copyright statement
>in your code, as it is a big chunk of work. You may check out
>As I see there's a nice statement from the US Government that
>puts this code in the public domain, you may simply use the basic
>suggestions you find in the above mentioned page, augmented by
>that statement. You may modify your patch, or simply send a
>followup to your ITS (reply to the message you got from the its).
>You have to do this because copyright statements in principle
>cannot be changed by others (I guess).
>Dr. Pierangelo Masarati | voice: +39 02 2399 8309
>Dip. Ing. Aerospaziale | fax: +39 02 2399 8334
>Politecnico di Milano | mailto:email@example.com
>via La Masa 34, 20156 Milano, Italy | http://www.aero.polimi.it/~masarati