Subject: Re: chroot jail for ftpd
To: gabriel rosenkoetter <>
From: Alfred Perlstein <>
List: tech-kern
Date: 10/18/2001 16:35:04
* gabriel rosenkoetter <> [011018 16:22] wrote:
> On Thu, Oct 18, 2001 at 04:47:30PM -0400, Thor Lancelot Simon wrote:
> > Yeah, let's do a special-purpose hack instead of actually enforcing the
> > consistent rule that executable code has to come from an executable file.
> > 
> > Gack.
> Hrm. Well, when you put it that way...
> But we have the unfortunate problem that enforcing this rule
> consistently is something that we have been *not* doing for a very
> long time. It's also something that other Unix-like operating
> systems have been not doing for a very long time. (And probably
> won't start doing any time soon.)
> Doing it right sounds great. But maybe with, a little leniency about
> the immediacy of the change?

Sorry for jumping here but I fail to see the point of blocking
access to shared libraries based on noexec filesystems or 
files without the execute bit set.  Nothing is stopping some
whacko from opening the file and using it as a shared object
by read(2)'ing into a data area to jump into.

Noexec should simply be used to prevent users from uploading
their own binaries and/or accidentally running binaries meant
for other platforms/OSes or non execuatables.

-Alfred Perlstein []
'Instead of asking why a piece of software is using "1970s technology,"
 start asking why software is ignoring 30 years of accumulated wisdom.'