Re: [PATCH] ptrace RSE bug

Petr Tesarik
2007-10-17T19:48:47Z

Petr Tesarik wrote:
>[...]
> 4. While talking about RNAT, does the RBS syncing back and forth
> handle correctly the case when part of the RNAT stored in the backing
> store belongs to the kernel registers? It must not be possible to change
> the NAT bits for kernel registers from userspace!
>
> Maybe it's not an issue, because I tried to actually exploit this
> bug, and my attempts failed.

I've just verified that put_rnat() does the right thing here (even
prevents setting NaT for syscall arguments), so modifying RNAT bits is
no problem. The other things still apply.

Regards,
Petr Tesarik