Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758514Ab1EZUfX (ORCPT ); Thu, 26 May 2011 16:35:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1025 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752321Ab1EZUfW (ORCPT ); Thu, 26 May 2011 16:35:22 -0400 Date: Thu, 26 May 2011 16:35:02 -0400 From: Vivek Goyal To: Dan Rosenberg Cc: Dan Rosenberg , Tony Luck , linux-kernel@vger.kernel.org, davej@redhat.com, kees.cook@canonical.com, davem@davemloft.net, eranian@google.com, torvalds@linux-foundation.org, adobriyan@gmail.com, penberg@kernel.org, hpa@zytor.com, Arjan van de Ven , Andrew Morton , Valdis.Kletnieks@vt.edu, Ingo Molnar , pageexec@freemail.hu Subject: Re: [RFC][PATCH] Randomize kernel base address on boot Message-ID: <20110526203502.GK29496@redhat.com> References: <1306269105.21443.20.camel@dan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1306269105.21443.20.camel@dan> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1062 Lines: 22 On Tue, May 24, 2011 at 04:31:45PM -0400, Dan Rosenberg wrote: > This introduces CONFIG_RANDOMIZE_BASE, which randomizes the address at > which the kernel is decompressed at boot as a security feature that > deters exploit attempts relying on knowledge of the location of kernel > internals. The default values of the kptr_restrict and dmesg_restrict > sysctls are set to (1) when this is enabled, since hiding kernel > pointers is necessary to preserve the secrecy of the randomized base > address. What happens to /proc/iomem interface which gives us the physical memory location where kernel is loaded. kexec-tools relies on that interface heavily so we can not take it away. And if we can not take it away then I think somebody should be easibly be able to calculate this randomized base address. Thanks Vivek -- 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/