From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yu-cheng Yu Subject: [PATCH v10 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Date: Wed, 29 Apr 2020 15:07:11 -0700 Message-ID: <20200429220732.31602-6-yu-cheng.yu@intel.com> References: <20200429220732.31602-1-yu-cheng.yu@intel.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20200429220732.31602-1-yu-cheng.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit Cc: Yu-cheng Yu List-Id: linux-arch.vger.kernel.org Shadow Stack provides protection against function return address corruption. It is active when the processor supports it, the kernel has CONFIG_X86_INTEL_SHADOW_STACK_USER, and the application is built for the feature. This is only implemented for the 64-bit kernel. When it is enabled, legacy non-shadow stack applications continue to work, but without protection. Signed-off-by: Yu-cheng Yu --- v10: - Change SHSTK to shadow stack in the help text. - Change build-time check to config-time check. - Change ARCH_HAS_SHSTK to ARCH_HAS_SHADOW_STACK. arch/x86/Kconfig | 30 +++++++++++++++++++++++++++ scripts/as-x86_64-has-shadow-stack.sh | 4 ++++ 2 files changed, 34 insertions(+) create mode 100755 scripts/as-x86_64-has-shadow-stack.sh diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1197b5596d5a..c98f82fffe85 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1947,6 +1947,36 @@ config X86_INTEL_TSX_MODE_AUTO side channel attacks- equals the tsx=auto command line parameter. endchoice +config AS_HAS_SHADOW_STACK + def_bool $(success,$(srctree)/scripts/as-x86_64-has-shadow-stack.sh $(CC)) + help + Test the assembler for shadow stack instructions. + +config X86_INTEL_CET + def_bool n + +config ARCH_HAS_SHADOW_STACK + def_bool n + +config X86_INTEL_SHADOW_STACK_USER + prompt "Intel Shadow Stacks for user-mode" + def_bool n + depends on CPU_SUP_INTEL && X86_64 + depends on AS_HAS_SHADOW_STACK + select ARCH_USES_HIGH_VMA_FLAGS + select X86_INTEL_CET + select ARCH_HAS_SHADOW_STACK + help + Shadow Stacks provides protection against program stack + corruption. It's a hardware feature. This only matters + if you have the right hardware. It's a security hardening + feature and apps must be enabled to use it. You get no + protection "for free" on old userspace. The hardware can + support user and kernel, but this option is for user space + only. + + If unsure, say y. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/scripts/as-x86_64-has-shadow-stack.sh b/scripts/as-x86_64-has-shadow-stack.sh new file mode 100755 index 000000000000..fac1d363a1b8 --- /dev/null +++ b/scripts/as-x86_64-has-shadow-stack.sh @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +echo "wrussq %rax, (%rbx)" | $* -x assembler -c - -- 2.21.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Yu-cheng Yu Subject: [PATCH v10 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack Date: Wed, 29 Apr 2020 15:07:11 -0700 Message-ID: <20200429220732.31602-6-yu-cheng.yu@intel.com> In-Reply-To: <20200429220732.31602-1-yu-cheng.yu@intel.com> References: <20200429220732.31602-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang Cc: Yu-cheng Yu List-ID: Message-ID: <20200429220711.JTJHKProke_-JBit7DKWupDLk6jV0p_5q3LhQif_AHo@z> Shadow Stack provides protection against function return address corruption. It is active when the processor supports it, the kernel has CONFIG_X86_INTEL_SHADOW_STACK_USER, and the application is built for the feature. This is only implemented for the 64-bit kernel. When it is enabled, legacy non-shadow stack applications continue to work, but witho= ut protection. Signed-off-by: Yu-cheng Yu --- v10: - Change SHSTK to shadow stack in the help text. - Change build-time check to config-time check. - Change ARCH_HAS_SHSTK to ARCH_HAS_SHADOW_STACK. arch/x86/Kconfig | 30 +++++++++++++++++++++++++++ scripts/as-x86_64-has-shadow-stack.sh | 4 ++++ 2 files changed, 34 insertions(+) create mode 100755 scripts/as-x86_64-has-shadow-stack.sh diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 1197b5596d5a..c98f82fffe85 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1947,6 +1947,36 @@ config X86_INTEL_TSX_MODE_AUTO side channel attacks- equals the tsx=3Dauto command line parameter. endchoice =20 +config AS_HAS_SHADOW_STACK + def_bool $(success,$(srctree)/scripts/as-x86_64-has-shadow-stack.sh $(C= C)) + help + Test the assembler for shadow stack instructions. + +config X86_INTEL_CET + def_bool n + +config ARCH_HAS_SHADOW_STACK + def_bool n + +config X86_INTEL_SHADOW_STACK_USER + prompt "Intel Shadow Stacks for user-mode" + def_bool n + depends on CPU_SUP_INTEL && X86_64 + depends on AS_HAS_SHADOW_STACK + select ARCH_USES_HIGH_VMA_FLAGS + select X86_INTEL_CET + select ARCH_HAS_SHADOW_STACK + help + Shadow Stacks provides protection against program stack + corruption. It's a hardware feature. This only matters + if you have the right hardware. It's a security hardening + feature and apps must be enabled to use it. You get no + protection "for free" on old userspace. The hardware can + support user and kernel, but this option is for user space + only. + + If unsure, say y. + config EFI bool "EFI runtime service support" depends on ACPI diff --git a/scripts/as-x86_64-has-shadow-stack.sh b/scripts/as-x86_64-ha= s-shadow-stack.sh new file mode 100755 index 000000000000..fac1d363a1b8 --- /dev/null +++ b/scripts/as-x86_64-has-shadow-stack.sh @@ -0,0 +1,4 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 + +echo "wrussq %rax, (%rbx)" | $* -x assembler -c - --=20 2.21.0