From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752928AbaENICV (ORCPT ); Wed, 14 May 2014 04:02:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:6702 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751938AbaENICQ (ORCPT ); Wed, 14 May 2014 04:02:16 -0400 Date: Wed, 14 May 2014 16:02:01 +0800 From: Dave Young To: keescook@chromium.org, hpa@zytor.com, linux-kernel@vger.kernel.org Subject: [PATCH v2] x86: kaslr to avoid setup_data regions Message-ID: <20140514080201.GA18922@dhcp-16-198.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline 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 X86 will pass setup_data region while necessary, these regions could be overwitten by kernel due to kaslr. Thus iterate and add setup regions to mem_avoid[] in this patch. Set max mem avoid entries 32, hopefully it will be enough. Signed-off-by: Dave Young --- arch/x86/boot/compressed/aslr.c | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) Index: linux-2.6/arch/x86/boot/compressed/aslr.c =================================================================== --- linux-2.6.orig/arch/x86/boot/compressed/aslr.c +++ linux-2.6/arch/x86/boot/compressed/aslr.c @@ -110,8 +110,9 @@ struct mem_vector { unsigned long size; }; -#define MEM_AVOID_MAX 5 +#define MEM_AVOID_MAX 32 static struct mem_vector mem_avoid[MEM_AVOID_MAX]; +static int mem_avoid_nr; static bool mem_contains(struct mem_vector *region, struct mem_vector *item) { @@ -135,6 +136,28 @@ static bool mem_overlaps(struct mem_vect return true; } +static void mem_avoid_setup_data(void) +{ + struct setup_data *data; + u64 pa_data; + + if (mem_avoid_nr >= MEM_AVOID_MAX) { + debug_putstr("KASLR: too many setup_data ranges.\n"); + return; + } + + pa_data = real_mode->hdr.setup_data; + while (pa_data) { + data = (struct setup_data *)pa_data; + if (pa_data < CONFIG_RANDOMIZE_BASE_MAX_OFFSET) { + mem_avoid[mem_avoid_nr].start = pa_data; + mem_avoid[mem_avoid_nr].size = sizeof(*data) + data->len; + mem_avoid_nr++; + } + pa_data = data->next; + } +} + static void mem_avoid_init(unsigned long input, unsigned long input_size, unsigned long output, unsigned long output_size) { @@ -177,6 +200,9 @@ static void mem_avoid_init(unsigned long /* Avoid stack memory. */ mem_avoid[4].start = (unsigned long)free_mem_end_ptr; mem_avoid[4].size = BOOT_STACK_SIZE; + mem_avoid_nr = 5; + + mem_avoid_setup_data(); } /* Does this memory vector overlap a known avoided area? */ @@ -184,7 +210,7 @@ static bool mem_avoid_overlap(struct mem { int i; - for (i = 0; i < MEM_AVOID_MAX; i++) { + for (i = 0; i < mem_avoid_nr; i++) { if (mem_overlaps(img, &mem_avoid[i])) return true; }