From owner-freebsd-hackers Tue Feb 4 17: 3:52 2003 Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 26F5837B401 for ; Tue, 4 Feb 2003 17:03:51 -0800 (PST) Received: from geekpunk.net (adsl-154-184-139.bna.bellsouth.net [68.154.184.139]) by mx1.FreeBSD.org (Postfix) with ESMTP id CDC4C43F75 for ; Tue, 4 Feb 2003 17:03:44 -0800 (PST) (envelope-from bandix@geekpunk.net) Received: from localhost.my.domain (taran [127.0.0.1]) by geekpunk.net (8.12.6/8.12.6) with ESMTP id h14KAiUd019720; Tue, 4 Feb 2003 14:10:44 -0600 (CST) (envelope-from bandix@geekpunk.net) Received: (from bandix@localhost) by localhost.my.domain (8.12.6/8.12.6/Submit) id h14KAhCC019719; Tue, 4 Feb 2003 14:10:43 -0600 (CST) (envelope-from bandix) Date: Tue, 4 Feb 2003 14:10:43 -0600 From: "Brandon D. Valentine" To: Justin Lundy Cc: FreeBSD-Hackers Subject: Re: [eugene@securityarchitects.com: Re: Preventing exploitation with rebasing] Message-ID: <20030204201043.GR16038@geekpunk.net> References: <20030204195114.GA92636@cvs.tegatai.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030204195114.GA92636@cvs.tegatai.com> User-Agent: Mutt/1.4i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Tue, Feb 04, 2003 at 11:51:14AM -0800, Justin Lundy wrote: > Has similar work been done in FreeBSD been done? This would be a nice > feature in 5.0-CURRENT. We had SecureBSD, and the IBM port of propolice, > but both projects appear to be defunct at present. If we can integrate > MAC into the kernel, why not port over OpenBSD's rebasing implementation > from /src/sys/kern/kern_exec.c? > > ----- Forwarded message from Eugene Tsyrklevich ----- > "Add a possibility to add a random offset to the stack on exec. This makes > it slightly harder to write generic buffer overflows. This doesn't really > give any real security, but it raises the bar for script-kiddies and it's > really cheap. AFAIK, no. No similiar work has been done in FreeBSD. Personally I think if one is going to expend effort in making the stack more secure the proper way to do this is to follow NetBSD's example and switch to a signal trampoline provided by libc so that stack pages can be marked non-executable in the first place. Adding random offsets to the stack is never going to be more than a hack. But, the surest way to test whether or not there is support for this among actual FreeBSD developers (of which I am not one) is to post a patch. You'll know pretty quickly one way or the other. Brandon D. Valentine -- brandon@dvalentine.com http://www.geekpunk.net "We've been raised on replicas of fake and winding roads, and day after day up on this beautiful stage we've been playing tambourine for minimum wage, but we are real; I know we are real." -- David Berman To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message