Re: [Linux-privs-discuss] SELinux & Linux-privs projects

[Casey Schaufler <casey@sgi.com>]

Stephen Smalley wrote:

> The POSIX.1e MAC tightly couples policy and enforcement because
> it is designed for a particular kind of security policy.
> It assumes a certain kind of security label.

I don't know who told you that, but it certainly wasn't
anyone who worked on the standard. The 1e MAC specification
is explicitly devoid of any such assumptions. That's one
reason there's no specification on Moldy directories, for
example.

> It assumes hierarchical relationships among labels.

It assumes that there are two relationships, equality
and dominance, between labels. I can easily show labeling
schemes which are cyclic, but which can be represented
in terms of these relationships.

> It assumes that it is
> sufficient to treat all operations as being read, write, or execute.

That's because those are the only operations POSIX systems
support! It's implicit in being a POSIX (DRAFT) standard.

> In order to support Type Enforcement or Role-Based Access
> Control or other kinds of mandatory security, you are very likely
> to need to change or at least recompile the file system code,
> the networking code, etc.

Yes, and?

-- 

Casey Schaufler				Manager, Trust Technology, SGI
casey@sgi.com				voice: 650.933.1634
casey_p@pager.sgi.com			Pager: 888.220.0607

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