Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933373AbbGGUbK (ORCPT ); Tue, 7 Jul 2015 16:31:10 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:16584 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757939AbbGGUUx (ORCPT ); Tue, 7 Jul 2015 16:20:53 -0400 From: Yinghai Lu To: Kees Cook , "H. Peter Anvin" , Baoquan He Cc: linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH 08/42] x86, kaslr: Get correct max_addr for relocs pointer Date: Tue, 7 Jul 2015 13:19:54 -0700 Message-Id: <1436300428-21163-9-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.8.4.5 In-Reply-To: <1436300428-21163-1-git-send-email-yinghai@kernel.org> References: <1436300428-21163-1-git-send-email-yinghai@kernel.org> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2111 Lines: 54 There is boundary checking for pointer in kaslr relocation handling. Current code is using output_len, and that is VO (vmlinux after objcopy) file size plus vmlinux.relocs file size. That is not right, as we should use loaded address for running. At that time parse_elf already move the sections according to ELF headers. The valid range should be VO [_text, __bss_start) loaded physical addresses. In the patch, add export for __bss_start to voffset.h and use it to get max_addr. Signed-off-by: Yinghai Lu --- 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 50daea7..e12a93c 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -40,7 +40,7 @@ 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 db97bdf..8fb74ba 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -234,7 +234,7 @@ 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 -- 1.8.4.5 -- 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/