On Fri, 2009-03-27 at 17:09 -0500, Nicolas Williams wrote: > On Fri, Mar 27, 2009 at 09:22:42AM -0400, Stephen Smalley wrote: > > On Fri, 2009-03-27 at 08:55 -0400, Stephen Smalley wrote: > > > You can't represent Type Enforcement via MLS/BLP; TE is strictly more > > > expressive than BLP, not the other way around. It also has no inherent > > > notion of dominance; the access matrix is explicitly defined and may > > > include intransitive relationships, which are required for integrity > > > goals and guaranteed invocation. > > I thought that MLS compartment -> DTE type. Is that not the case? I > realize that DTE does not have an inherent notion of dominance, but for > _documents_ (as opposed to operating system- or application-specific > files like /etc/shadow) there surely must be a way to establish > dominance, no? That seems important to me. No, there just needs to be a way to establish authorization. The internal logic for determining whether data of a given label is allowed to transit over a network interface of a given label is policy-specific and shouldn't be limited to the dominance relation. It can just be represented as a permission check on a label pair for a given object class, and then the security policy logic can internally decide yes/no on that permission based on any combination of the dominance relation, the TE access matrix, or any other policy constraints. -- Stephen Smalley National Security Agency -- This message was distributed to subscribers of the selinux mailing list. If you no longer wish to subscribe, send mail to majordomo@xxxxxxxxxxxxx with the words "unsubscribe selinux" without quotes as the message.
