Question

This question is from chapter 29 in the textbook: "Introduction to Computer Security" by Matt Bishop

1. The second example in Section 29.2.1 states that “user level processes can alter page table entries, so references to those data structures also fail to meet the second requirement.” How can an operating system prevent a user level process from altering its page table entries?

Answer 1

Ans-

" User level threads can alter the page table entries, so references to those data structures are also fail to meet second can requirement ." Operating system can present the user level threads from altering page entries as given below-

-> storing page table addressing in the memory portion of the operating system on the restricted area of the memory.

-> when the user level threads are trying to access the page table address, then it will generated the trap error as they are trying to access the restricted portion of the memory.

-> this operation to carry out is the responsibility of the memory manager which is one of the major component of the operating system.