Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759207AbaDXWxj (ORCPT ); Thu, 24 Apr 2014 18:53:39 -0400 Received: from mail-qa0-f43.google.com ([209.85.216.43]:47704 "EHLO mail-qa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757886AbaDXWuH (ORCPT ); Thu, 24 Apr 2014 18:50:07 -0400 MIME-Version: 1.0 In-Reply-To: <20140424025016.GB2180@darkstar.nay.redhat.com> References: <20140424023544.GA2180@darkstar.nay.redhat.com> <20140424025016.GB2180@darkstar.nay.redhat.com> Date: Thu, 24 Apr 2014 15:50:06 -0700 X-Google-Sender-Auth: _6KC_Dapj1Yp5Dv10rXP68YslIE Message-ID: Subject: Re: kaslr should avoid setup_data region From: Kees Cook To: Dave Young Cc: "H. Peter Anvin" , LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ah, it sounds like boot_params.hdr.setup_data contains a series of e820-like entries chained together as a linked list? Which loaders currently populate that? Looks like EFI? Seems like arch/x86/boot/compressed/eboot.c works on setup_data at least. I won't be in a position to test EFI booting for a while. If someone else took this, that would make it get fixed much faster. Do you have examples where this is actually causing failures? -Kees On Wed, Apr 23, 2014 at 7:50 PM, Dave Young wrote: > On 04/23/14 at 07:43pm, Kees Cook wrote: >> On Wed, Apr 23, 2014 at 7:35 PM, Dave Young wrote: >> > Hello Kees >> > >> > I'm worrying that setup_data regions could be overwitten by randomize >> > kernel base. Would you like to fix it in kaslr code? >> > >> > One problem is there could be a lot of setup_data regions but current >> > mem_avoid is an fixed array. >> >> Sure, can you give me some examples? Seems like it shouldn't be too >> hard to have the mem_avoid logic walk additional areas. > > Great, To walk through the list just like the function parse_setup_data in > arch/x86/kernel/setup.c > > Thanks > Dave -- 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/