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.