Jamie Lokier wrote:
>
> > > is a downside to doing this. If, for example, timeofday is
> > > available in a raw form on one of these data pages, and user-space
> > > code can read that page at will (without going to the kernel), you
> > preventing a rogue process from accessing the info directly might be a bit
> > harder, w/o giving up the main benefit -- speed. There certainly seems to
> > be a market for a runtime (global) on/off switch at least.
>
> If you switch it off, the process knows you've switched it off and
> may behave differently.
>
> It's probably possible to lie to the process for gettimeofday and signal
> operations though -- have the kernel unmap the page for those processes,
[for _all_ processes, as this is supposed to be a global mapping]
> and have a ptrace SEGV handler which provides results as if the page
> were still mapped.
hmm, might work. since it would be detectable anyway (eg timing)
the question is would it be worth the extra complexity...
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This archive was generated by hypermail 2b29 : Wed Mar 15 2000 - 21:00:14 EST