Re: Arbitrary Sandbox

["Randy Brukardt" <randy@rrsoftware.com>]

"Shark8" <onewingedshark@gmail.com> wrote in message 
news:203d63cf-42a9-49ef-82cd-943d77b5e438@c21g2000yqi.googlegroups.com...
On Feb 11, 8:10 pm, "Randy Brukardt" <ra...@rrsoftware.com> wrote:
>>
>> Windows and Unix-based systems do not have a properly designed (native)
>> runtime environment -- stuff we did to make Janus/Ada more secure on DOS
>> extenders in the 1980s never made it to OS environments).
>
>Could you elaborate on that? (Both what's needed to make such an
>environment and what was done on Janus/Ada.)

The vast majority of programs do not have self-modifying code, and it 
shouldn't be possible for them to run such code in any way. If that's the 
case, most code-injection attacks cannot happen.

We used the native segmentation of the Intel hardware to completely separate 
code and data in Janus/Ada programs. It was impossible to accidentally 
execute data simply because the data wasn't even in the same address space.

Of course, some programs do need self-modifying code, and an OS would have 
provided an API for that purpose. But it should have been rarely used.

Now, I recognize that DEP was added to Intel hardware to provide some of 
this protection, but the problem is that a lot of programs can't use it 
because of the basic architectual mistake (including GNAT programs until 
recently, which is why I had to leave it off on my computer - boo). Plus 
requiring a new feature to get this protection is annoying as it was always 
available in Intel hardware (back to 80286); people just had to use it and 
they didn't. (I think that was a consequence of Windows NT copying the bad 
Unix memory model more than an intentional decision - and of course the 
security issues hadn't popped up so much then). [Aside: Intel has 
de-emphasized segments in modern hardware to the point that you probably 
couldn't do this today, as you would pay a nasty performance price. Boo 
again (understandable, though).]

                                                Randy.