On 2/10/2021 11:33 AM, Kees Cook wrote:

On Wed, Feb 10, 2021 at 09:56:40AM -0800, Yu-cheng Yu wrote:

quoted

Shadow Stack provides protection against function return address
corruption.  It is active when the processor supports it, the kernel has
CONFIG_X86_CET enabled, 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 <redacted>
---
  arch/x86/Kconfig           | 23 +++++++++++++++++++++++
  arch/x86/Kconfig.assembler |  5 +++++
  2 files changed, 28 insertions(+)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 21f851179ff0..1138b5fa9b4f 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig

@@ -28,6 +28,7 @@ config X86_64
  	select ARCH_HAS_GIGANTIC_PAGE
  	select ARCH_SUPPORTS_INT128 if CC_HAS_INT128
  	select ARCH_USE_CMPXCHG_LOCKREF
+	select ARCH_HAS_SHADOW_STACK
  	select HAVE_ARCH_SOFT_DIRTY
  	select MODULES_USE_ELF_RELA
  	select NEED_DMA_MAP_STATE

@@ -1951,6 +1952,28 @@ config X86_SGX
  
  	  If unsure, say N.
  
+config ARCH_HAS_SHADOW_STACK
+	def_bool n
+
+config X86_CET
+	prompt "Intel Control-flow protection for user-mode"
+	def_bool n
+	depends on X86_64

This depends isn't needed any more. With that fixed:

Yes, that's right.  I will remove it.

Reviewed-by: Kees Cook <redacted>

Thanks!

--
Yu-cheng