Re: [ldapext] empty-groupOfNames-issue

Michael Ströder <michael@stroeder.com> Fri, 04 December 2015 14:11 UTC

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To: Andrew Findlay <andrew.findlay@skills-1st.co.uk>
References: <5661765D.6040603@stroeder.com> <20151204134757.GE3643@slab.skills-1st.co.uk>
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Subject: Re: [ldapext] empty-groupOfNames-issue
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Andrew Findlay wrote:
> On Fri, Dec 04, 2015 at 12:17:49PM +0100, Michael Ströder wrote:
> 
>> 1. Modified standard schema descriptions for 'groupOfNames' and
>> 'groupOfUniqueNames':
>>
>> This is the work-around already chosen by various vendors:
>> The MUST member or MUST uniqueMember is turned into MAY.
>>
>> + it just works, no interop-problems seen so far.
>> + no change required in LDAP clients
>> + no change required in access control rules
>> + no change required in other client or server-side code dealing with groups
>>
>> - It violates standardization best practices, most notably IANA considerations.
>> - It could serve as a bad example to change standard schema at will.
>>
>> Hopefully Rolf Sonneveld and Andrew Findlay will clearly comment on IANA
>> considerations.
> 
> I don't think there is an IANA consideration here. The modified schema
> is (currently) incorrect according to RFC4519 or is alternatively an
> experiment leading to a proposed change to a standard. In the latter
> case it would have to be accepted by IETF and published in a new RFC
> that obsoletes 4519. At that time, IANA would update the reference in
> the Object Identifiers table to point to the new document but would have
> no other involvement.

Ok.

Do you think that a complete replacement RFC _obsoleting_ RFC 4519 would be
needed?  If the ldapext community would agree on changing the standard wouldn't
a small RFC _updating_ RFC 4519 also be sufficient?

> In practice I cannot see such a change ever being accepted into the
> standards track. If anything, the relatively wide distribution of
> non-conformant implementations makes a stronger case for deprecating
> these objectclasses for new deployments.
> 
> The definition of groupOfNames goes right back to X.521(1988) and it was
> already broken at that point:
> 
> a)	member was a mandatory attribute

Hmm, I somewhat disagree here.  But maybe I'm just too pragmatic. ;-)

> b)	Nested groups were mentioned in the text but the semantics
> 	were left undefined

Please let us keep the scope limited to the empty-groupOfNames-issue.  I'm not
keen on opening the can-of-worms on semantics of nested groups.

>> 2. new object class 'groupOfEntries'
>>
>> Andrew kindly wrote an mini I-D defining a new structural object class
>> 'groupOfEntries' simply with MAY member instead of MUST meant as direct
>> replacement for 'groupOfNames'.
>>
>> http://tools.ietf.org/html/draft-findlay-ldap-groupofentries
>>
>> + Very simple
>> + Fully compliant to standardization best practices
>>
>> - It's not clear whether it was widely adopted in deployments.
> 
> Maybe not in the exact form I described in that I-D, but functionally
> equivalent objectclasses have been in most of my customers' systems.
> It could be argued that the corrupted form of groupOfNames described
> above is actually proof of widespread deployment of an analogous class.

Hmm, the wording gets a bit blurry here.
How would you explain the clear distinction between 1. and 2.?

Ciao, Michael.