Re: Authoritative Hooks

sarnoldat_private

On Mon, Nov 05, 2001 at 05:13:47PM -0800, Casey Schaufler wrote:
> Unless the branch is the official Phase II. We believe that would
> address all of the issues We can think of from my side. We expect
> it would raise a bunch elsewhere, and that's fair. 

I think such a 'phase 2' repository can be made to work.

Most of the reasons to avoid opening up this phase 2 repository revolve
around one simple fact: we really have no idea what will make it into
the linux kernel in 'phase 1'.[1]

This is where the real value of getting a jump-start on phase 2 could
lie; rather than trying to closely track phase 1 with the exception of
being authoritative, it could try to be the 'right' solution, for some
value of 'right'. It could be something along the lines of reducing all
security checks to operations on security* blobs, similar to:
	operation_allowed(S_PTRACE, ptracing_task->security, ptracee_task->security);
Where the security blobs would include all relevant information.

Or, heck, take gregkh's advice and turn everything into a filesystem.
Then, kernel operations could check the contents of files such as
	security_namespace:/open/proc/inode 
or      security_namespace:/ptrace/ptracing_task/ptracee_task
to allow or disallow this operation. (Though, I'm sure gregkh would
chime in, "the kernel shouldn't be reading files", so lets be clear that
this half-baked idea is mine -- "use a filesystem" is gregkh's refrain
for interacting with userspace. :)

In short -- use the vagueness of the final form of phase 1 as a starting
point for phase 2's work, rather than allow the nebulous nature of
unaccepted code be a restraint.

My only concern is that it might seem highly presumptious to start phase
2 while phase 1 is still far from a done deal. However, I think we've
pointed out often enough that LSM is far from being a done deal, so as
long as any accouncements of a phase 2 repository are couched in the
language of, "this is what we would *really* like to see in the linux
kernel in the long run" rather than, "we got our foot in the door, time
for our Evil Plan For World Dominiation", I think we wouldn't upset too
many people. :)

-- sarnold, hoping he didn't start Yet Another Flamewar^WEndless
Discussion On The Form Of The Hooks

[1]: Including the possibility that perhaps the only piece we only get in
could be the system call. 

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