From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WONMD-0003gu-FM for kexec@lists.infradead.org; Fri, 14 Mar 2014 08:20:46 +0000 From: WANG Chao Subject: [PATCH v2] x86, kaslr: Kernel base can be randomized at 0-1G offset. Date: Fri, 14 Mar 2014 16:20:18 +0800 Message-Id: <1394785218-25168-1-git-send-email-chaowang@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: kexec@lists.infradead.org Cc: dyoung@redhat.com, ebiederm@xmission.com, vgoyal@redhat.com With kASLR enabled (CONFIG_RANDOMIZED_BASE=y), kernel virtual address base is PAGE_OFFSET plus a randomized offset from 0 to 1G. Current kexec-tools gets kernel vaddr and size from /proc/kcore. It assumes kernel vaddr start/end is within the range [0,512M). If kaslr enabled, kernel vaddr start/end will stay at [0+offset, 512M+offset). To adapt kaslr, introduce a new macro X86_64_RANDOMIZED_BASE_MAX_OFFSET to address the max offset and use this macro to filter out the kernel text PT_LOAD from /proc/kcore. Signed-off-by: WANG Chao --- kexec/arch/i386/crashdump-x86.c | 3 ++- kexec/arch/i386/crashdump-x86.h | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c index cb19e7d..1e6d3a3 100644 --- a/kexec/arch/i386/crashdump-x86.c +++ b/kexec/arch/i386/crashdump-x86.c @@ -156,7 +156,8 @@ static int get_kernel_vaddr_and_size(struct kexec_info *UNUSED(info), /* Look for kernel text mapping header. */ if ((saddr >= X86_64__START_KERNEL_map) && - (eaddr <= X86_64__START_KERNEL_map + X86_64_KERNEL_TEXT_SIZE)) { + (saddr <= X86_64__START_KERNEL_map + X86_64_RANDOMIZE_BASE_MAX_OFFSET) && + (eaddr - saddr < X86_64_KERNEL_TEXT_SIZE)) { saddr = _ALIGN_DOWN(saddr, X86_64_KERN_VADDR_ALIGN); elf_info->kern_vaddr_start = saddr; size = eaddr - saddr; diff --git a/kexec/arch/i386/crashdump-x86.h b/kexec/arch/i386/crashdump-x86.h index e68b626..71a09f8 100644 --- a/kexec/arch/i386/crashdump-x86.h +++ b/kexec/arch/i386/crashdump-x86.h @@ -15,6 +15,9 @@ int load_crashdump_segments(struct kexec_info *info, char *mod_cmdline, #define X86_64_PAGE_OFFSET_PRE_2_6_27 0xffff810000000000ULL #define X86_64_PAGE_OFFSET 0xffff880000000000ULL +/* kASLR - Kernel base offset could be randomized up to 1G */ +#define X86_64_RANDOMIZE_BASE_MAX_OFFSET 0x40000000 + #define X86_64_MAXMEM 0x3fffffffffffUL /* Kernel text size */ -- 1.8.5.3 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec