Re: Virtual Machine in the abstract (was Re: [DotGNU]What languages should DotGNU support?)

[Fergus Henderson]

On 02-Dec-2002, Gopal V <address@hidden> wrote:
> If memory serves me right, Fergus Henderson wrote:
> > AFAIK pnetC and other C/C++ compilers for .NET (lcc, MSVC) all generate
> > unverifiable IL code, in general.  So they don't provide any security
> > guarantees.
> 
> Unsafe , not unverifiable ...

Well, it's both unsafe and unverifiable.

> Unsafe code can mess up memory, and segfault
> like any other C code .. If you use C/C++ , you already got a gun locked 
> on to your foot ... :-)

Not necessarily.  I believe there are error-checking C interpreters
around, that can provide safe execution of C code.  It's just that
pnetC isn't one of them, AFAIK, and nor are any of the other C
implementations that generate .NET IL.

> All the security guarantees it can provide as the usual provided by any 
> VM .. blocking native calls, checking for permissions to a library , and
> isolated file storage ..

That doesn't help, because unverifiable IL code can write to arbitrary
memory locations and can as a result cause the VM interpreter to execute
arbitrary machine code.

-- 
Fergus Henderson <address@hidden>  |  "I have always known that the pursuit
The University of Melbourne         |  of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh>  |     -- the last words of T. S. Garp.