Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752831AbcD2AJo (ORCPT ); Thu, 28 Apr 2016 20:09:44 -0400 Received: from mail-pf0-f171.google.com ([209.85.192.171]:33400 "EHLO mail-pf0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752647AbcD2AJR (ORCPT ); Thu, 28 Apr 2016 20:09:17 -0400 From: Kees Cook To: Ingo Molnar Cc: Kees Cook , Yinghai Lu , Baoquan He , Ingo Molnar , "H. Peter Anvin" , Borislav Petkov , Vivek Goyal , Andy Lutomirski , lasse.collin@tukaani.org, Andrew Morton , Dave Young , LKML Subject: [PATCH 6/6] x86/boot: Correctly bounds-check relocations Date: Thu, 28 Apr 2016 17:09:08 -0700 Message-Id: <1461888548-32439-7-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.6.3 In-Reply-To: <1461888548-32439-1-git-send-email-keescook@chromium.org> References: <1461888548-32439-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2018 Lines: 48 From: Yinghai Lu Relocation handling performs bounds checking on the resulting calculated addresses. The existing code uses output_len (VO size plus relocs size) as the max address. This is not right since the max_addr check should stop at the end of VO and exclude bss, brk, etc, which follows. The valid range should be VO [_text, __bss_start] in the loaded physical address space. This patch adds an export for __bss_start in voffset.h and uses it to set the correct limit for max_addr. Signed-off-by: Yinghai Lu Cc: Baoquan He [kees: rewrote changelog] Signed-off-by: Kees Cook --- arch/x86/boot/compressed/Makefile | 2 +- arch/x86/boot/compressed/misc.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index adef26d22224..75f2233b8414 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -57,7 +57,7 @@ LDFLAGS_vmlinux := -T hostprogs-y := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include -sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p' +sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p' quiet_cmd_voffset = VOFFSET $@ cmd_voffset = $(NM) $< | sed -n $(sed-voffset) > $@ diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index bee6238e7cfc..8f0253d8c7ff 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -191,7 +191,7 @@ static void handle_relocations(void *output, unsigned long output_len) int *reloc; unsigned long delta, map, ptr; unsigned long min_addr = (unsigned long)output; - unsigned long max_addr = min_addr + output_len; + unsigned long max_addr = min_addr + (VO___bss_start - VO__text); /* * Calculate the delta between where vmlinux was linked to load -- 2.6.3