Re: Mapping to 0x0

[Robert Hancock]

Jan Engelhardt wrote:
> The mmap() usually succeeds and maps something at address 0x00000000. Now 
> what if the kernel would try to execute this (of course badly programmed) 
> code in the context of this very process?
>
>     int (*callback)(int xyz) = NULL;
>     callback();
>
> Would not be the badcode be executed with kernel privileges?

I'm not sure, but I would suspect it might, yes, at least on some 
platforms and configurations. However, this unlikely to be a serious 
problem, since any kernel code that executed a callback method which 
could be a NULL without checking for that would blow up the system in 
the vast majority of cases where nothing was mapped at address 0.

--
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from hancockr@xxxxxxxxxxxxx
Home Page: http://www.roberthancock.com/

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