[Cryptography] Do capabilities work? Do ACLs work?

[Bill Frantz]

On 2/12/15 at 3:04 PM, frantz at pwpconsult.com (Bill Frantz) wrote:

>This is the first time anyone in this discussion has mentioned 
>how you change ACLs. Access to them is, as far as I can tell, 
>outside the ACL security system. Not good.

I will note in passing that capabilities can be used to 
implement ACLs.[1] (Why you would want to is another question.) 
If you also use capabilities to control how ACLs may be changed, 
you have a principled answer to the problem of controlling that access.

My wire and I could set up our systems so we both have "owner" 
control over all of our shared files. Not being able to do that 
is the principle reason we share an ID and password. (Note: I'm 
saying the security controls on our MacOSX system can't 
implement our security policy.)

Cheers - Bill

[1] There are two published approaches to implementing ACLs with 
capabilities. 
<http://www.cis.upenn.edu/~KeyKOS/NanoKernel/NanoKernel.html> 
describes the KeyKOS Unix implementation, which included Unix 
style ACLs. Another approach would be to use the a Horton-like 
system 
<https://www.usenix.org/legacy/event/hotsec07/tech/full_papers/miller/miller.pdf> 
to implement ACLs. I'd be glad to consult on such an effort at 
my customary rates, but I'm officially retired now, and such an 
effort sounds like work. :-)

-------------------------------------------------------------------------
Bill Frantz        | Re: Hardware Management Modes: | Periwinkle
(408)356-8506      | If there's a mode, there's a   | 16345 
Englewood Ave
www.pwpconsult.com | failure mode. - Jerry Leichter | Los Gatos, 
CA 95032