Rep:RE: Rep:Re: Rep:Re: [f-cpu] TLB right + resume

["Nicolas Boulay" <nicolas.boulay@ifrance.com>]

-----Message d'origine-----
De: John Graley <JGraley@sonicblue.com>
A: "'f-cpu@seul.org'" <f-cpu@seul.org>
Date: 21/08/02
Objet: RE: Rep:Re: Rep:Re: [f-cpu] TLB right + resume



> -----Original Message-----
> From: Michael Riepe [mailto:michael@stud.uni-hannover.de]
> Sent: 20 August 2002 13:40
> To: f-cpu@seul.org
> Subject: Re: Rep:Re: Rep:Re: [f-cpu] TLB right + resume
> 
> 
> On Tue, Aug 20, 2002 at 09:05:08AM +0000, Nicolas Boulay wrote:
> [...]
> > > 3- execute librairy call to execute excve with /bin/sh to 
> have a shell
> > > access.
> > 
> > That's a SW problem.
> > 
> > >>> A compiler problem, so an abi problem. The last 
> security problem in
> > case of buffer overflow.
> > 
> > > 4- diseable any possiblity of buffer overflow.
> > 
> > Dto.
> > 
> > >>> ??? don't understand that word.
> 
> Sorry... it was supposed to mean "same as above".
> 
> > > 5- Protect part of the kernel (driver) from it-self
> > 
> > That's what you need fine-grained access rights for.
> > 
> > >>> Do you think it's wise to protect the kernel from it-self ? 
> 
> It's a side-effect when you protect the kernel from user code.
> 
> > >>> What you think about the idea of tagged page that could 
> only be used
> > by tagged read&write instructions (to protect data page of 
> the kernel
> > and return stack write) ?
> 
> I'm afraid that will help only if you compile all your 
> binaries yourself
> (otherwise, they might contain "trojan writes").

Surely it would be a simple matter in software to search through
executables
looking for the op-codes of illegal instructions before execution?

>>>This instruction are normaly used by the compiler to manage the
return adress stack, so the presence of this instruction are normal. We
want to avoid the change of the normal process run, like writing beside
an array to scratch the return adress.
nicO

Cheers, John
 
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