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    SubjectRe: [announce] [patch] NX (No eXecute) support for x86, 2.6.7-rc2-bk2
    On Wed, Jun 02, 2004 at 02:13:13PM -0700, Linus Torvalds wrote:
    >
    >
    > On Wed, 2 Jun 2004, Ingo Molnar wrote:
    > >
    > > If the NX feature is supported by the CPU then the patched kernel turns
    > > on NX and it will enforce userspace executability constraints such as a
    > > no-exec stack and no-exec mmap and data areas. This means less chance
    > > for stack overflows and buffer-overflows to cause exploits.
    >
    > Just out of interest - how many legacy apps are broken by this? I assume
    > it's a non-zero number, but wouldn't mind to be happily surprised.

    based on execshield in FC1.. about zero.

    >
    > And do we have some way of on a per-process basis say "avoid NX because
    > this old version of Oracle/flash/whatever-binary-thing doesn't run with
    > it"?

    yes those aren't compiled with the PT_GNU_STACK elf flag and run with the
    stack executable just fine. GCC will also emit a "make the stack executable"
    flag when it emits code that puts stack trampolines up.
    That all JustWorks(tm).[unhandled content-type:application/pgp-signature]
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