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Re: Access control

I have a followup requirement where I need to be able to restrict read access to the groups as well as write access. I only want the owners of an object to be able to read and write that object. 

The reason for wanting to do this is to ensure that a user only sees the groups that they can edit when they are using LDAP Account Manager. We have quite a large number of groups and I am trying to head off users complaining that they can't find the group they need to edit.

I've been experimenting with the ACLs to try to get it to work but I can only get it to work if the owner is explicitly mentioned, rather than indirectly mentioned as per the "member of a group" approach.

The ACLs so far are:

access to dn.>
    by users read
    by * none

access to dn.>
    by users read
    by * none

access to dn.sub="ou=groups,dc=example,dc=com"
    attrs=objectClass,uniqueMember
    by users read
    by * none

access to dn.sub="ou=groups,dc=example,dc=com"
    by dnattr="owner" write
    by users none
    by * none

access to dn.sub="ou=groups,dc=example,dc=com"
    by set="this/owner/uniqueMember & user" write
    by users none
    by * none

(I know that having 'by users none' is redundant but it is there to be explicit)

The purpose of the ACLs is

1. Allow everyone to see the OU structure in the domain.
2. Allow everyone to see the OUs within the groups OU.
3. The intention here is to grant enough access to the attributes of a group so that slapd can then evaluate the uniqueMember attribute. It isn't entirely clear to me whether slapd needs a rule like this or should be able to evaluate membership etc before it applies acls for the user.
4. Allow directly mentioned owners to write, nothing to everyone else.
5. Allow indirectly mentioned owners to write, nothing to everyone else.

Thanks for any suggestions/observations.

Philip


On 30 January 2013 08:00, Andrew Findlay <andrew.findlay@skills-1st.co.uk> wrote:
On Thu, Jan 24, 2013 at 12:22:18PM +0000, Philip Colmer wrote:

> What I want/need to be able to do is for LDAP to read the DN of the group that
> has permission, in the same what that it does with dnattr. I thought that I had
> read something about this being possible with sets, but slapd.access says that
> "The statement set=<pattern> is undocumented yet." so I'm not clear if that is
> the most appropriate way to proceed.
>
>
> Can someone please advise on how this might be accomplished?

Sets are indeed the answer. The documentation only exists in
the OpenLDAP FAQ-o-matic at present, but you need something
like this:

access to dn.sub="ou=groups,dc=example,dc=com"
        by set="this/manager/member & user" write
        by users read
        by * none

That ACL would give write access to members of any group whose
DN is listed in the "manager" attribute.

The basic idea is that "this/manager/member" produces a set of DNs,
"user" produces a set containing the DN of the bound user,
and "&" generates the intersection of the two sets.
If the result is a non-empty set then the "by" clause applies.

Andrew
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