Re: Understanding Linux addr space, malloc, and heap

Vincent W. Freeh wrote:

First, thanks for all the help and attention.  I am learning much.

I think the focus of this discussion should be on mprotect. I understand that spec says it only works on mmap'd memory. So does malloc use mmap? If not why does it work at all?

Probably the most problematic issue, tho, is why does mprotect return 0 even though it failed to change permissions on the 66th page?

Do you have code that shows this?

I tried to change the example in the mprotect man page to loop N times (N given on the command line) malloc'ing and mprotect'ing N pages and then accessing the N'th page and it always gave SIGSEGV, for any N from 1 to 100.

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• References:
  • Re: Understanding Linux addr space, malloc, and heap
    • From: "Vincent W. Freeh" <[email protected]>
  • Re: Understanding Linux addr space, malloc, and heap
    • From: Arjan van de Ven <[email protected]>
  • Re: Understanding Linux addr space, malloc, and heap
    • From: "Vincent W. Freeh" <[email protected]>
  • Re: Understanding Linux addr space, malloc, and heap
    • From: Arjan van de Ven <[email protected]>
  • Re: Understanding Linux addr space, malloc, and heap
    • From: "Vincent W. Freeh" <[email protected]>
  • Re: Understanding Linux addr space, malloc, and heap
    • From: Kyle Moffett <[email protected]>
  • Re: Understanding Linux addr space, malloc, and heap
    • From: "Vincent W. Freeh" <[email protected]>

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