Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755521Ab2JBUeJ (ORCPT ); Tue, 2 Oct 2012 16:34:09 -0400 Received: from mail-ia0-f174.google.com ([209.85.210.174]:50416 "EHLO mail-ia0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754887Ab2JBUeH (ORCPT ); Tue, 2 Oct 2012 16:34:07 -0400 MIME-Version: 1.0 In-Reply-To: References: <20120820180037.GV4232@outflux.net> Date: Tue, 2 Oct 2012 13:34:06 -0700 X-Google-Sender-Auth: aWyU9wWkKSi9_4BtMM_ThsQerOA Message-ID: Subject: Re: [PATCH] hardening: add PROT_FINAL prot flag to mmap/mprotect From: Kees Cook To: Ard Biesheuvel Cc: linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1352 Lines: 37 Hi, On Mon, Aug 20, 2012 at 2:48 PM, Ard Biesheuvel wrote: >> This seems like a good idea to me. It would allow more than just the >> loader to harden userspace allocations. It's a more direct version of >> PaX's "MPROTECT" feature[1]. That feature hardens existing loaders, >> but doesn't play nice with JITs (like Java), but this lets a loader >> (or JIT) opt-in to the protection and have some direct control over it. > > If desired, additional restrictions can be imposed by using the > security framework, e.g,, disallow non-final r-x mappings. Interesting; what kind of interface did you have in mind? >> It seems like there needs to be a sensible way to detect that this flag is >> available, though. > > I am open for suggestions to address this. Our particular > implementation of the loader (on an embedded system) tries to set it > on the first mmap invocation, and stops trying if it fails. Not the > most elegant approach, I know ... Actually, that seems easiest. Has there been any more progress on this patch over-all? -Kees -- Kees Cook Chrome OS Security -- 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/