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[RFC,v3,1/8] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking

Message ID 20180830144009.3314-2-yu-cheng.yu@intel.com (mailing list archive)
State New, archived
Headers show
Series Control Flow Enforcement: Branch Tracking, PTRACE | expand

Commit Message

Yu-cheng Yu Aug. 30, 2018, 2:40 p.m. UTC
The user-mode indirect branch tracking support is done mostly by
GCC to insert ENDBR64/ENDBR32 instructions at branch targets.
The kernel provides CPUID enumeration, feature MSR setup and
the allocation of legacy bitmap.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
 arch/x86/Kconfig  | 12 ++++++++++++
 arch/x86/Makefile |  7 +++++++
 2 files changed, 19 insertions(+)

Comments

Randy Dunlap Aug. 30, 2018, 7:38 p.m. UTC | #1
On 08/30/2018 07:40 AM, Yu-cheng Yu wrote:
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 2cfe11e1cf7f..0d97b03f35f6 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -1941,6 +1941,18 @@ config X86_INTEL_SHADOW_STACK_USER
>  
>  	  If unsure, say y.
>  
> +config X86_INTEL_BRANCH_TRACKING_USER
> +	prompt "Intel Indirect Branch Tracking for user-mode"
> +	def_bool n
> +	depends on CPU_SUP_INTEL && X86_64
> +	select X86_INTEL_CET
> +	select ARCH_HAS_PROGRAM_PROPERTIES
> +	---help---
> +	  Indirect Branch Tracking provides hardware protection against return-/jmp-
> +	  oriented programing attacks.

	           programming

> +
> +	  If unsure, say y
> +
>  config EFI
>  	bool "EFI runtime service support"
>  	depends on ACPI
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Patch

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2cfe11e1cf7f..0d97b03f35f6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1941,6 +1941,18 @@  config X86_INTEL_SHADOW_STACK_USER
 
 	  If unsure, say y.
 
+config X86_INTEL_BRANCH_TRACKING_USER
+	prompt "Intel Indirect Branch Tracking for user-mode"
+	def_bool n
+	depends on CPU_SUP_INTEL && X86_64
+	select X86_INTEL_CET
+	select ARCH_HAS_PROGRAM_PROPERTIES
+	---help---
+	  Indirect Branch Tracking provides hardware protection against return-/jmp-
+	  oriented programing attacks.
+
+	  If unsure, say y
+
 config EFI
 	bool "EFI runtime service support"
 	depends on ACPI
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 00927853e409..0da5121c30db 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -159,6 +159,13 @@  ifdef CONFIG_X86_INTEL_SHADOW_STACK_USER
   endif
 endif
 
+# Check compiler ibt support
+ifdef CONFIG_X86_INTEL_BRANCH_TRACKING_USER
+  ifeq ($(call cc-option-yn, -fcf-protection=branch), n)
+      $(error CONFIG_X86_INTEL_BRANCH_TRACKING_USER not supported by compiler)
+  endif
+endif
+
 #
 # If the function graph tracer is used with mcount instead of fentry,
 # '-maccumulate-outgoing-args' is needed to prevent a GCC bug