Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 2 May 2003 18:46:20 -0400 | From | Chuck Ebbert <> | Subject | Re: [Announcement] "Exec Shield", new Linux security feature |
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John Bradford wrote:
> Slightly off-topic, but does anybody know whether IA64 or x86-64 allow > you to make the stack non-executable in the same way you can on SPARC?
IA64 supports a mind-boggling variety of page-level protection modes, including execute-only pages that usermode can jump to and get 'promoted' to lower (more privileged) levels. _And_ it supports protection keys that can be attached to pages so your process needs to have the key loaded into a register to touch those pages. The keys can themselves be marked read/write/execute disable on loading, so the supervisor can give you a key that keeps you from executing pages even if their page-level protections would otherwise allow it.
AMD64 supports a simple NX (no execute) bit that keeps both supervisor and user code from executing, and that's probably all anyone really needs.
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