Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162691Ab3DEUBH (ORCPT ); Fri, 5 Apr 2013 16:01:07 -0400 Received: from mail-ie0-f172.google.com ([209.85.223.172]:65157 "EHLO mail-ie0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162637Ab3DEUBG (ORCPT ); Fri, 5 Apr 2013 16:01:06 -0400 MIME-Version: 1.0 In-Reply-To: <515DE0C9.3030709@zytor.com> References: <1365106055-22939-1-git-send-email-keescook@chromium.org> <1365106055-22939-4-git-send-email-keescook@chromium.org> <515DE0C9.3030709@zytor.com> Date: Fri, 5 Apr 2013 13:01:04 -0700 X-Google-Sender-Auth: yd6P0mM77AgrXADT0R1O2ZalJyc Message-ID: Subject: Re: [PATCH 3/3] x86: kernel base offset ASLR From: Yinghai Lu To: "H. Peter Anvin" Cc: Kees Cook , Linux Kernel Mailing List , kernel-hardening@lists.openwall.com, Thomas Gleixner , Ingo Molnar , "the arch/x86 maintainers" , Jarkko Sakkinen , Matthew Garrett , Matt Fleming , Eric Northup , Dan Rosenberg , Julien Tinnes , Will Drewry Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 977 Lines: 24 On Thu, Apr 4, 2013 at 1:21 PM, H. Peter Anvin wrote: > I have to admit to being somewhat skeptical toward KASLR with only 8 > bits of randomness. There are at least two potential ways of > dramatically increasing the available randomness: > > 1. actually compose the kernel of multiple independently relocatable > pieces (maybe chunk it on 2M boundaries or something.) > > 2. compile the kernel as one of the memory models which can be executed > anywhere in the 64-bit address space. The cost of this would have > to be quantified, of course. Why just let bootloader to load kernel on random address instead? For our 64bit bzImage, boot loader could load kernel to anywhere above 4G. Thanks Yinghai -- 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/