From owner-freebsd-hackers Fri Feb 18 14:20:59 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from monkeys.com (i180.value.net [206.14.136.180]) by hub.freebsd.org (Postfix) with ESMTP id 3BD1B37BAF3 for ; Fri, 18 Feb 2000 14:20:55 -0800 (PST) (envelope-from rfg@monkeys.com) Received: from monkeys.com (localhost [127.0.0.1]) by monkeys.com (8.9.3/8.9.3) with ESMTP id OAA12504; Fri, 18 Feb 2000 14:20:47 -0800 (PST) To: freebsd-hackers@freebsd.org, gnu-gcc@gnu.org Subject: Defending against buffer overflows. Date: Fri, 18 Feb 2000 14:20:47 -0800 Message-ID: <12502.950912447@monkeys.com> From: "Ronald F. Guilmette" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG My attention has just been called to: http://immunix.org/StackGuard/mechanism.html Given all of the buffer overrun vulnerabilities that have been found in various network daemons over time, this seems like a worthwhile sort of technique to apply when compiling, in particular, network daemons and/or servers. I don't entirely agree with this fellow's approach however. I think that the ``canary'' word should be located at the bottom end of the current stack frame, i.e. in a place where no buffer overrun could possibly clobber it. Seems to me that this would be a nice and useful little enhancement for gcc. I wouldn't mind having something like a -fbuffer-overrun-checks option for gcc, and I would definitely use it when compiling network daemons. Anybody else got an opinion? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message