Re: Non-Exec stack patches

From: David Mosberger
Date: Wed Mar 24 2004 - 13:03:38 EST


>>>>> On Wed, 24 Mar 2004 12:24:54 -0500, Jakub Jelinek <jakub@xxxxxxxxxx> said:

>> Huh? Only one mprotect() call is needed to make the entire stack
>> executable.

Jakub> Nope. Think about multithreaded apps.

I said one mprotect() to make the entire stack executable. Obviously,
if you have multiple stacks, you need one call per stack. Big deal.

Jakub> Furthermore, getting the exact extents of the particular
Jakub> stack is difficult to find for applications, but e.g. the
Jakub> threading library has to know such things.

And how is this a kernel problem? There are other reasons why
applications need to know the stack extents (think garbage collector)
and it's entirely glibc's failing if it's difficult to determine the
stack extent.

--david
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