Not sure it completely answers my question, but this is my current analysis

- Solar designer's patch is now in some vendor kernels already
- "NX" does exactly the same, but via a different mechanism, the performance difference is unclear (if any)
- This is obviously a Good Thing, because only a very small percentage of ia32 compatible machines currently have AMD64 compatible CPUs
- Windows lags miles behind, with WinXP SP2 only implementing this function on NX-capable CPUs

Plus I *suspect*

- "return-into-libc" exploits will still work with NX enabled (as they do with Solar Designer's patch)

I haven't seen any on Win32, but they are theoretically possible (return into MSVCRT.dll or return into kernel32.dll, returning into (for example), WinExec, CreateProcess or system())

Slarty