From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932363AbWDZEnw (ORCPT ); Wed, 26 Apr 2006 00:43:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932362AbWDZEnv (ORCPT ); Wed, 26 Apr 2006 00:43:51 -0400 Received: from smtpout.mac.com ([17.250.248.186]:16367 "EHLO smtpout.mac.com") by vger.kernel.org with ESMTP id S932360AbWDZEnu (ORCPT ); Wed, 26 Apr 2006 00:43:50 -0400 In-Reply-To: <200604251952.k3PJqj2J010248@turing-police.cc.vt.edu> References: <20060425161139.87285.qmail@web26109.mail.ukl.yahoo.com> <1145984201.3114.34.camel@laptopd505.fenrus.org> <878xpto53w.fsf@hades.wkstn.nix> <1145993869.3114.38.camel@laptopd505.fenrus.org> <200604251952.k3PJqj2J010248@turing-police.cc.vt.edu> Mime-Version: 1.0 (Apple Message framework v746.3) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: Cc: Arjan van de Ven , Nix , Axelle Apvrille , drepper@gmail.com, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, disec-devel@lists.sourceforge.net Content-Transfer-Encoding: 7bit From: Kyle Moffett Subject: Re: [ANNOUNCE] Release Digsig 1.5: kernel module for run-timeauthentication of binaries Date: Wed, 26 Apr 2006 00:43:07 -0400 To: Valdis.Kletnieks@vt.edu X-Mailer: Apple Mail (2.746.3) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Apr 25, 2006, at 15:52:45, Valdis.Kletnieks@vt.edu wrote: > On Tue, 25 Apr 2006 21:37:48 +0200, Arjan van de Ven said: >> On Tue, 2006-04-25 at 19:57 +0100, Nix wrote: >>> On Tue, 25 Apr 2006, Arjan van de Ven said: >>>> so you didn't sign perl ? or bash ? >>> >>> You can write an elf loader in bash?! >> >> I've not tried it.. but afaics bash scripts are sufficiently >> turing complete to pull it off ;) > > Well, somebody did 'shasm' (an assembler in bash), so I don't see > any reason you can't do an elf loader... (OK, so you *might* have > to write a machine emulator in bash, store the binary in an array, > and emulate the sucker...) Well I know that there are ways in Perl to overwrite arbitrary memory (it's considered a bug of a certain XS library, although it has no security implications because you could do the equivalent in Perl anyways). I would assume that it's quite possible to do the same in bash with a specially formatted bash script. Once you can scribble on arbitrary memory, you can load a compiled ELF loader and execute it without much trouble at all. A signed perl binary would open a hole the size of a barn door in your scheme, I think. Cheers, Kyle Moffett