Re: linux capabilities and ACLs

Mirian Crzig Lennox (mirian@xensei.com)
05 Feb 1999 13:37:55 -0500

john halewood <john@firewall.unidec.co.uk> writes:
>
> not quite. denial is always applied first. in fact, the thing
> that's been missing from this discussion is any mention
> of VMS, which has probably the most complete ACL implementation
> I've seen. it was borrowed (sometimes almost byte for byte) by
> n*t, although they left out some of the more obscure bits.
> I never could get the hang of being able to execute programs
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> even though i couldn't read the contents of the directory
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> that they resided in, or even read them themselves.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Get ready for a shock, then:

(On a machine running Redhat Linux 5.2):

$ mkdir foo
$ cp /bin/date foo
$ chmod 100 foo/date
$ chmod 100 foo
$ ls foo
ls: foo: Permission denied
$ cat foo/date
cat: foo/date: Permission denied
$ ./foo/date
Fri Feb 5 13:28:53 EST 1999

You don't need ACLs to pull this little trick; ordinary POSIX
permissions will do.

-- 
Mirian Crzig Lennox                                Systems Anarchist
          "There's a New World Order coming every minute.
                      Make mine extra cheese."


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