Subject: Re: read {write,only} stack
To: None <cshapiro@sparky.ic.sunysb.edu, current-users@NetBSD.ORG>
From: Ross Harvey <ross@teraflop.com>
List: current-users
Date: 08/20/1997 01:47:34
 > > For the i386 architecture there was some linux hacks that would stop
 > > the stack being executable - dunno how portable they would be, if at
 > > all.  You need to be careful about doing this though as the changes
 > > are more than just a kernel hack.  IIRC gcc relies on an executable
 > > stack for some of it's trampoline code which means that some things
 > > could break with a non-executable stack.  The up side is that it does
 > > provide a convenient method of preventing the fixed-buffer overrun type
 > > exploits that are currently fashionable in the cracker community.
 > 
 > I am suprised that Linux is able to make the stack non-executable despite
 > it's heavly reliance on trampoline code.  Whatever these hacks are, they
 > must be really (really really) ugly.

Umm, if this info came from the discussion on bugtraq earlier this year,
then I think it was just a demo mod that probably did break a lot of things.
It's not like it's a normal linux feature or anything.