FreeBSD x86 vs x86-64 Questions about Security

[zombyfork at gmail.com (Coleman Kane)]

Hi Jimmy.


On Fri, 11 Feb 2005 07:54:05 +0000, Jimmy <freebsd_(_at_)_oranged_(_dot_)_to> wrote:
> Hello,
> 
> I Am interested to know several questions..
> 
> - Currently I am using FreeBSD x86-64 I have compiled the majority of my
> applications up using the right compiler flags to support the 64bit OS.
> Is there any way within the Operating system that I can turn off 32bit
> support?

You should be able to remove COMPAT_IA32 from your kernel config.

> 
> - Are applications that have been compiled for the amd-64 platform still
> vulnerable to x86 style attacks because of the backwards compatability
> mode? (eg remote buffer overflows in say.. openssh?).
> 

AMD64 has a per-page NX (non-executable) bit, I however am not aware
if FreeBSD uses this in the code pages.

--coleman

> Thanks
> 
> J
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