Michael Ströder wrote:
> On 8/21/22 16:51, Alceu Rodrigues de Freitas Junior wrote:
>> I do know memberOf is not a requirement: regular exporting data from 
>> /etc/passwd, /etc/shadow and /etc/group as LDIF files are working as 
>> expected.
>>
>> But wouldn't it be a better option to use it instead of handling data in 
>> multiple places (users and groups) instead of just the groups entries in the 
>> tree?
>>
>> At least this is my understanding regarding the usefulness of memberOf. Not 
>> sure either if that would become a performance issue.
> 
> Not sure I really understand what you're after but I give it a try:
> 
> With POSIX groups besides determining user's group membership you also have 
> to read some POSIX group attributes like cn and gidNumber from the LDAP 
> posixGroup
> entry.
> 
> Simple NSS clients can build the passwd and group maps by just reading all 
> posixGroup and posixAccount entries at once (full enumeration).
> 
> This might not work in bigger environments with several ten thousand of also 
> possibly very large groups. So some NSS clients allow to disable enumerating 
> the
> whole maps and try to read data just when needed. In such a situation it can 
> be useful to make use of memberOf attribute, e.g. when determining the group
> membership of a single user, to avoid having to read the full and possible 
> very big group entries. Together with slapo-deref the NSS client can also 
> read the
> group entries' POSIX attribute gidNumber referenced by user entry in one 
> round-trip.

You can just search for all groups where member=<user>, returning no 
attributes, or returning only cn and gidNumber. Again, memberOf is not helpful 
here
and no other extensions are needed.

-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/

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