From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756361Ab2IUTnV (ORCPT ); Fri, 21 Sep 2012 15:43:21 -0400 Received: from mga11.intel.com ([192.55.52.93]:49306 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753578Ab2IUTnT (ORCPT ); Fri, 21 Sep 2012 15:43:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.80,464,1344236400"; d="scan'208";a="225201981" From: "H. Peter Anvin" To: Linux Kernel Mailing List , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner Cc: Linus Torvalds , Kees Cook , Linda Wang , Matt Fleming , "H. Peter Anvin" Subject: =?UTF-8?q?=5BPATCH=2000/11=5D=20x86=3A=20Supervisor=20Mode=20Access=20Prevention?= Date: Fri, 21 Sep 2012 12:43:04 -0700 Message-Id: <1348256595-29119-1-git-send-email-hpa@linux.intel.com> X-Mailer: git-send-email 1.7.6.5 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Supervisor Mode Access Prevention (SMAP) is a new security feature disclosed by Intel in revision 014 of the Intel® Architecture Instruction Set Extensions Programming Reference: http://software.intel.com/sites/default/files/319433-014.pdf When SMAP is active, the kernel cannot normally access pages that are user space (U=1). Since the kernel does have the need to access user space pages under specific circumstances, an override is provided: the kernel can access user space pages if EFLAGS.AC=1. For system data structures, e.g. descriptor tables, that are accessed by the processor directly, SMAP is active even in CPL 3 regardless of EFLAGS.AC. SMAP also includes two new instructions, STAC and CLAC, to flip the AC flag more quickly. Note: patch 01/11 is already in tip:x86/cpufeature. List of patches: x86, cpufeature: Add feature bit for SMAP x86-32, mm: The WP test should be done on a kernel page x86, smap: Add CR4 bit for SMAP x86, alternative: Use .pushsection/.popsection x86, alternative: Add header guards to x86, smap: Add a header file with macros for STAC/CLAC x86, uaccess: Merge prototypes for clear_user/__clear_user x86, smap: Add STAC and CLAC instructions to control user space access x86, smap: Turn on Supervisor Mode Access Prevention x86, smap: A page fault due to SMAP is an oops x86, smap: Reduce the SMAP overhead for signal handling Diff stat: Documentation/kernel-parameters.txt | 6 ++- arch/x86/Kconfig | 11 ++++ arch/x86/ia32/ia32_signal.c | 12 +++-- arch/x86/ia32/ia32entry.S | 6 ++ arch/x86/include/asm/alternative-asm.h | 9 +++- arch/x86/include/asm/alternative.h | 32 ++++++------ arch/x86/include/asm/cpufeature.h | 1 + arch/x86/include/asm/fpu-internal.h | 10 ++-- arch/x86/include/asm/futex.h | 19 +++++-- arch/x86/include/asm/processor-flags.h | 1 + arch/x86/include/asm/smap.h | 91 ++++++++++++++++++++++++++++++++ arch/x86/include/asm/uaccess.h | 28 ++++++---- arch/x86/include/asm/uaccess_32.h | 3 - arch/x86/include/asm/uaccess_64.h | 3 - arch/x86/include/asm/xsave.h | 10 ++-- arch/x86/kernel/cpu/common.c | 29 ++++++++++- arch/x86/kernel/entry_64.S | 11 ++++- arch/x86/kernel/signal.c | 24 +++++---- arch/x86/lib/copy_user_64.S | 7 +++ arch/x86/lib/copy_user_nocache_64.S | 3 + arch/x86/lib/getuser.S | 10 ++++ arch/x86/lib/putuser.S | 8 +++- arch/x86/lib/usercopy_32.c | 13 ++++- arch/x86/lib/usercopy_64.c | 3 + arch/x86/mm/fault.c | 18 ++++++ arch/x86/mm/init_32.c | 2 +- 26 files changed, 301 insertions(+), 69 deletions(-)