Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753372Ab3DEMMz (ORCPT ); Fri, 5 Apr 2013 08:12:55 -0400 Received: from cantor2.suse.de ([195.135.220.15]:55904 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161177Ab3DEMMx (ORCPT ); Fri, 5 Apr 2013 08:12:53 -0400 Date: Fri, 5 Apr 2013 14:12:20 +0200 (CEST) From: Jiri Kosina X-X-Sender: jikos@twin.jikos.cz To: Kees Cook Cc: linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , x86@kernel.org, Jarkko Sakkinen , Matthew Garrett , Matt Fleming , Eric Northup , Dan Rosenberg , Julien Tinnes , Will Drewry Subject: Re: [PATCH 3/3] x86: kernel base offset ASLR In-Reply-To: <1365106055-22939-4-git-send-email-keescook@chromium.org> Message-ID: References: <1365106055-22939-1-git-send-email-keescook@chromium.org> <1365106055-22939-4-git-send-email-keescook@chromium.org> User-Agent: Alpine 2.00 (LRH 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1150 Lines: 28 On Thu, 4 Apr 2013, Kees Cook wrote: > This creates CONFIG_RANDOMIZE_BASE, so that the base offset of the kernel > can be randomized at boot. > > This makes kernel vulnerabilities harder to reliably exploit, especially > from remote attacks and local processes in seccomp containers. Keeping > the location of kernel addresses secret becomes very important when using > this feature, so enabling kptr_restrict and dmesg_restrict is recommended. If we are going to take the KASLR path at all, and assuming this is done purely because of security, I'd suggest not only vaguely mentioning this requirement in the changelog (and calling it recommendation), but make it a hard prerequisity. Without kernel addresses being invisible to userspace, this feature is completely useless, but might provide very false sense of security if just blindly enabled by random Joe Bofh. -- Jiri Kosina SUSE Labs -- 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/