From patchwork Wed Apr 15 21:04:46 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kristen Carlson Accardi X-Patchwork-Id: 11492039 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1E94D81 for ; Wed, 15 Apr 2020 21:06:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 10AAE20787 for ; Wed, 15 Apr 2020 21:06:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2442250AbgDOVGW (ORCPT ); Wed, 15 Apr 2020 17:06:22 -0400 Received: from mga03.intel.com ([134.134.136.65]:64180 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2442228AbgDOVFf (ORCPT ); Wed, 15 Apr 2020 17:05:35 -0400 IronPort-SDR: WlL8J0k03OaBIolOfp+CZtNZMDbrpCC81vqutJ7XjrbRtdqeSno0t9pQNBu31LzsQFvDNk8pFu ydER298UGeDQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2020 14:05:18 -0700 IronPort-SDR: Y40uVd+P74lLUKeRusKoiPA8XYqHaH2O5MnWgeowvptaQZp656CMoN5LsabEpfLzz/rBr21F9T 8ipIh+tzLoOg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,388,1580803200"; d="scan'208";a="455035560" Received: from kcaccard-mobl.amr.corp.intel.com (HELO kcaccard-mobl1.jf.intel.com) ([10.209.116.191]) by fmsmga006.fm.intel.com with ESMTP; 15 Apr 2020 14:05:15 -0700 From: Kristen Carlson Accardi To: keescook@chromium.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, Masahiro Yamada , Michal Marek , x86@kernel.org Cc: arjan@linux.intel.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecomb@intel.com, linux-kbuild@vger.kernel.org Subject: [PATCH 4/9] x86: Makefile: Add build and config option for CONFIG_FG_KASLR Date: Wed, 15 Apr 2020 14:04:46 -0700 Message-Id: <20200415210452.27436-5-kristen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200415210452.27436-1-kristen@linux.intel.com> References: <20200415210452.27436-1-kristen@linux.intel.com> MIME-Version: 1.0 Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org Allow user to select CONFIG_FG_KASLR if dependencies are met. Change the make file to build with -ffunction-sections if CONFIG_FG_KASLR Signed-off-by: Kristen Carlson Accardi --- Makefile | 4 ++++ arch/x86/Kconfig | 13 +++++++++++++ 2 files changed, 17 insertions(+) diff --git a/Makefile b/Makefile index 70def4907036..337b72787200 100644 --- a/Makefile +++ b/Makefile @@ -866,6 +866,10 @@ ifdef CONFIG_LIVEPATCH KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone) endif +ifdef CONFIG_FG_KASLR +KBUILD_CFLAGS += -ffunction-sections +endif + # arch Makefile may override CC so keep this after arch Makefile is included NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1d6104ea8af0..6aaece89f712 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2182,6 +2182,19 @@ config RANDOMIZE_BASE If unsure, say Y. +config FG_KASLR + bool "Function Granular Kernel Address Space Layout Randomization" + depends on $(cc-option, -ffunction-sections) + depends on RANDOMIZE_BASE && X86_64 + help + This option improves the randomness of the kernel text + over basic Kernel Address Space Layout Randomization (KASLR) + by reordering the kernel text at boot time. This feature + uses information generated at compile time to re-layout the + kernel text section at boot time at function level granularity. + + If unsure, say N. + # Relocation on x86 needs some additional build support config X86_NEED_RELOCS def_bool y