Re: %gs:0 thread pseudoregister in oskit-mach

[Jeroen Dekkers]

On Sun, Apr 21, 2002 at 03:26:56PM -0400, Roland McGrath wrote:
> > You forgot to make the page table entries also user accessible. Other
> > than that, everything works perfect. Thank you.
> 
> Great.  Thanks for the fix, and thanks for testing.  Have you/can you also
> test to be absolutely sure that users cannot access anything but the one
> word from %gs, and that they cannot access >VM_MAX_ADDRESS using %ds
> (i.e. normal accesses)?  I'm pretty darn sure that is all correct, but just
> to be paranoid.

I tried to acces %gs:4 and this failed with an "illegal
instruction". I also tried to access 0xc0000000 which got a
segmentation fault. I don't know if I have to test more.

Jeroen Dekkers
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