possible parsing problem with OSI-DS 23 (Distinguished Names)

[Allan Cargille <[e-mail]>]

Hi Steve,

I think that the syntax presented in "A String Representation of
Distinguished Names" (OSI-DS 23 (v5) and draft-ietf-osids-distnames-05.txt)
needs to be modified slightly.  The question was raised in my mind when
I was considering how to parse such strings.

I think that the problem has to do with double quotation marks ("),
when this character occurs in a field value.  Obviously this would
only occur in bizarre cases.  There is nothing to distinguish whether
the double quotes are *part* of the value, or if they *terminate* the
value.  For example, I believe the following is ambiguous:

    (a) CN=joe, OU="ba"d"

or even worse,

    (b) CN=joe, OU="ba"d",OU="va"lue"

I believe that (b) could be legally parsed two ways, as two
attributes:

    CN=joe
    OU=ba"d",OU="val"ue
       ^^^^^^^^^^^^^^^^  where this is *one* string value

or as three attributes:

    CN=joe
    OU=ba"d
    OU=va"lue

If this is a problem, I thought of several solutions:

    1.  require that a double-quote mark in a value must always
	be included in <pair> notation (as \"\).  This would transform
	example (a) above to

	    CN=joe, OU="ba\"\d"

	I prefer this solution.  I don't think it would change the
	grammar much.

    2.  when a double-quote character is used in a value, require that
	two such characters be used.  This would transform example (a)
	above to

	    CN=joe, OU="ba""d"

Well, I just wanted to raise the question, and let the experts worry
about the solution.

Cheers,

allan
--
Allan Cargille                  Computer Sciences Department
Internet X.400 Project          University of Wisconsin-Madison
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