From patchwork Thu May 21 16:56:35 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: 11563499 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 816BE739 for ; Thu, 21 May 2020 16:58:03 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id E8E34207F7 for ; Thu, 21 May 2020 16:58:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E8E34207F7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18839-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 31939 invoked by uid 550); 21 May 2020 16:57:25 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 31874 invoked from network); 21 May 2020 16:57:23 -0000 IronPort-SDR: ICl9AWQXTosAmAMBbZ1c7AZuO7e4WqWxUiigiRtLvSc6dlHZITZGSftx+ESqmgrosSk2S41kYn Mj8QJeSPD5jg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False IronPort-SDR: Zw0HlnVb2QXZFYtGqKuEgUBIy0YtUb+Hn9kY1fGHVDXq6bxN8QeBgr2Texd/QYSXXUu4PHMexH gZE6NC5W2mFQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,418,1583222400"; d="scan'208";a="309094725" From: Kristen Carlson Accardi To: keescook@chromium.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, Masahiro Yamada , Michal Marek , x86@kernel.org, "H. Peter Anvin" Cc: arjan@linux.intel.com, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, rick.p.edgecombe@intel.com, Kristen Carlson Accardi , Tony Luck , linux-kbuild@vger.kernel.org Subject: [PATCH v2 4/9] x86: Makefile: Add build and config option for CONFIG_FG_KASLR Date: Thu, 21 May 2020 09:56:35 -0700 Message-Id: <20200521165641.15940-5-kristen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200521165641.15940-1-kristen@linux.intel.com> References: <20200521165641.15940-1-kristen@linux.intel.com> MIME-Version: 1.0 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 Reviewed-by: Tony Luck Tested-by: Tony Luck Reviewed-by: Kees Cook --- Makefile | 4 ++++ arch/x86/Kconfig | 13 +++++++++++++ 2 files changed, 17 insertions(+) diff --git a/Makefile b/Makefile index 04f5662ae61a..28e515baa824 100644 --- a/Makefile +++ b/Makefile @@ -862,6 +862,10 @@ 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 2d3f963fd6f1..50e83ea57d70 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2183,6 +2183,19 @@ 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