[AFS3-std] Re: Methods of Restricting AFS3 ACL rights

[Adam Megacz]

Andrew Deason <adeason@sinenomine.net> writes:
> The explanation for the various methods now exists as an Internet
> Draft, and can be found here:

AFAIK, a volume is the unit of space management, while a directory is
the unit of access management. [*]

Solving the problem being discussed while retaining this distinction
would involve:

  1. Allowing transitive ACLs.  Semantically, a transitive positive
     (negative) ACL has the same effect as if it were appended to the
     list of positive (negative) ACLs of every subdirectory.

  2. Allowing for complement principals.  Semantically, an ACL
     mentioning the complement of a pts group applies to all users who
     are not in that group.

Then one can:

  fs sa /afs/@cell/web/ !system:authuser a -negative -transitive

That said, this is a huge amount of work to implement, and maybe even
impossible to implement without creating incompatibilities.

So perhaps
a hack based on volume boundaries is the best compromise.

  - a

[*] The only two exceptions I know of are the "implicit ACL"
    http://www.dementia.org/twiki/bin/view/AFSLore/UsageFAQ#2_21_What_meaning_do_the_owner_g
    and the fact that you can't revoke "l" permissions from the "parent
    directory" of the root directory of a volume.