Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267903AbUIJVag (ORCPT ); Fri, 10 Sep 2004 17:30:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267920AbUIJVaV (ORCPT ); Fri, 10 Sep 2004 17:30:21 -0400 Received: from fw.osdl.org ([65.172.181.6]:45513 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S267903AbUIJV2j (ORCPT ); Fri, 10 Sep 2004 17:28:39 -0400 Date: Fri, 10 Sep 2004 14:28:29 -0700 From: Chris Wright To: "Serge E. Hallyn" Cc: Chris Wright , linux-kernel@vger.kernel.org, Axelle Apvrille , david.gordon@ericsson.com, gaspoucho@yahoo.com Subject: Re: [ANNOUNCE] Release Digsig 1.3.1: kernel module for run-time authentication of binaries Message-ID: <20040910142829.Q1924@build.pdx.osdl.net> References: <41407CF6.2020808@ericsson.com> <20040909092457.L1973@build.pdx.osdl.net> <41409378.5060908@ericsson.com> <20040909105520.U1924@build.pdx.osdl.net> <20040909190511.GB28807@escher.cs.wm.edu> <4140BFCE.8010701@ericsson.com> <20040909140349.C1924@build.pdx.osdl.net> <20040909214507.GA29412@escher.cs.wm.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20040909214507.GA29412@escher.cs.wm.edu>; from serue@us.ibm.com on Thu, Sep 09, 2004 at 05:45:07PM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1257 Lines: 32 * Serge E. Hallyn (serue@us.ibm.com) wrote: > > Thing is, x86 makes no distinction btween r/x so, have you tried mmaping > > with read, then executing (I haven't)? > > Yup, clearly that will work on x86. And so obviously DigSig is not > a solution to format and buffer overflows :) Nor, unfortunately, a heh > solution to code which for whatever reason exploited this behavior. That's what I was getting at. Beats me what's out there that does this, but I expect some stuff does, and it wouldn't get the same assurance. > > This has nothing to do with file permissions aside of read. All you need > > is read permission, then you can mmap(PROT_EXEC) which will kick off the > > check, and do deny_write_access. It's a freeform way to lock writers > > out of any readable file in the system. > > No, not "any readable file," because DigSig will not lock non-ELF files. Ahh, this is the part I had missed. thanks, -chris -- Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/