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Old 07-07-2010, 06:45 AM   #1
jaypas
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Memory Protection


Hi,
How would I demonstrate that memory resources allocated to one user or process are protected from access by another user or process?
JayPas
 
Old 07-07-2010, 07:17 AM   #2
imagine_me2
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This is a classic segmentation fault situation.
What you need to use is a type unsafe language like 'C'. Declare an array of say of size 00 and try to access the 101st place. This will give a segmentation fault. But this memory may not be allocated to any other process. Whether or not a memory is allocated to another process your program may not access any other memory location other than what is allocated to it. If you need more memory in run time you have to explicitly ask for it, and its upto the OS that you will be provided or not. Actually this error is due to the fault arising due to inability to calculate proper memory location using segmentation register.

Regards.
 
Old 07-07-2010, 08:10 AM   #3
johnsfine
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Quote:
Originally Posted by jaypas View Post
How would I demonstrate that memory resources allocated to one user or process are protected from access by another user or process?
1) That (and your similar threads) sounds like homework. Don't ask us to do your homework.

2) It also sounds like the typical "prove a negative" problem. I know "demonstrate" is less than "prove", but how much less? You can't prove that there isn't a hole in Linux security. You could look for a hole and fail to find it, but that doesn't prove it isn't there.

No experiment should even be considered a demonstration of such protection. A detailed code review of the relevant parts of the Linux source code could be considered a demonstration of that protection. But I assume you are not looking for a project anywhere near that difficult.
 
Old 07-08-2010, 12:40 PM   #4
pixellany
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Per the LQ Rules, please do not post homework assignments verbatim. We're happy to assist if you have specific questions or have hit a stumbling point, however. Let us know what you've already tried and what references you have used (including class notes, books, and Google searches) and we'll do our best to help. Also, keep in mind that your instructor might also be an LQ member.

Please feel free to start a new thread which meets the guidelines
 
  


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