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Re: Rep:Re: Rep:Re: [f-cpu] TLB resume



Michael Riepe a écrit :
> 
> On Thu, Aug 08, 2002 at 07:57:14AM +0000, Nicolas Boulay wrote:
> [...]
> > You forgot some: User processes may try to modify kernel pages, or let
> > the
> >
> > >>> They can't. They doesn't have write right on the kernel pages.
> 
> Consider this system call:
> 
>         read(fd, &kernel_page, page_length);
> 

Why you're read can't check if the given pages are a real user one ?
It's easy under linux 0-2Gb is for process, 2-4 Gb AS is for kernel.

How you're 3 bits right for superuser could avoid this ?

nicO

> --
>  Michael "Tired" Riepe <Michael.Riepe@stud.uni-hannover.de>
>  "All I wanna do is have a little fun before I die"
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