Subject: Re: IPSEC still fails on BETA2/vax (not anymore!)
To: Olaf Seibert <firstname.lastname@example.org>
From: Steven M. Bellovin <email@example.com>
Date: 07/15/2002 08:14:53
In message <20020715010315.A6339@polderland.nl>, Olaf Seibert writes:
>I wonder if there would be some other
>clever solution. Why is the kernel stack in the U area anyway? Can't it
>just grow on the normal process stack? Perhaps the answer is in the
>Lions book, or The Design and Implementation Of 4.xBSD, but I don't
>recall it exactly. Maybe it has something to do with pageability of the
>user stack ISTR (after some thinking).
The user-space stack? It's not trustable, may be badly formatted to =
start with, may not even be a stack. And any sensitive kernel data
that appears on the stack -- keys, for example, in the ipsec case -- =
would have to be thoroughly scrubbed.
It might be possible to get this right -- but it would be very =
difficult, and I don't know that I'd trust the resulting system.
Don't go there.
--Steve Bellovin, http://www.research.att.com/~smb (me)
http://www.wilyhacker.com ("Firewalls" book)