From owner-freebsd-hackers Tue Oct 22 11:02:02 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id LAA19723 for hackers-outgoing; Tue, 22 Oct 1996 11:02:02 -0700 (PDT) Received: from phaeton.artisoft.com (phaeton.Artisoft.COM [198.17.250.211]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id LAA19718 for ; Tue, 22 Oct 1996 11:02:00 -0700 (PDT) Received: (from terry@localhost) by phaeton.artisoft.com (8.6.11/8.6.9) id KAA08248; Tue, 22 Oct 1996 10:59:08 -0700 From: Terry Lambert Message-Id: <199610221759.KAA08248@phaeton.artisoft.com> Subject: Re: libc string routines don't check for NULL pointers To: proff@suburbia.net (Julian Assange) Date: Tue, 22 Oct 1996 10:59:08 -0700 (MST) Cc: imp@village.org, hackers@FreeBSD.org In-Reply-To: <199610221502.BAA23250@suburbia.net> from "Julian Assange" at Oct 23, 96 01:02:52 am X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk > > str*cmp and friends should be hard asses about this and should give > > the programer a nice core file when this happens, subject to local > > security constraints. NULL pointer checking can slow down these > > routines, but I've never seen numbers to back up speed differences. > > > > Just my humble opinion from about 10 years of doing this stick. > > Others may disagree. > > No need to do this, just make sure the vm system never maps page 0. Actually, it should be noted that SVR4 will map an empty page 0 on first fault (hiding subsequent faults entilrely) as a backward compatability "trick" for bogus programs. It's actually possible to turn this "feature" off using an undocumented compile-time option. Only problem is, some of the bogus programs are system programs. SVR4 needs to be run through Purify. 8-(. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.