diff mbox series

[v13,1/8] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking

Message ID 20200925145804.5821-2-yu-cheng.yu@intel.com (mailing list archive)
State New, archived
Headers show
Series Control-flow Enforcement: Indirect Branch Tracking | expand

Commit Message

Yu-cheng Yu Sept. 25, 2020, 2:57 p.m. UTC 
Introduce Kconfig option X86_BRANCH_TRACKING_USER.

Indirect Branch Tracking (IBT) provides protection against CALL-/JMP-
oriented programming attacks.  It is active when the kernel has this
feature enabled, and the processor and the application support it.
When this feature is enabled, legacy non-IBT applications continue to
work, but without IBT protection.

Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
---
v13:
- Update help text, and change default to N.
- Change X86_INTEL_* to X86_*.

v10:
- Change build-time CET check to config depends on.

 arch/x86/Kconfig | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4b28a0ce4594..15c7f2606c9d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1966,6 +1966,25 @@  config X86_SHADOW_STACK_USER
 
 	  If unsure, say N.
 
+config X86_BRANCH_TRACKING_USER
+	prompt "Intel Indirect Branch Tracking for user-mode"
+	def_bool n
+	depends on CPU_SUP_INTEL && X86_64
+	depends on $(cc-option,-fcf-protection)
+	select X86_CET
+	help
+	  Indirect Branch Tracking (IBT) provides protection against
+	  CALL-/JMP-oriented programming attacks.  It is active when
+	  the kernel has this feature enabled, and the processor and
+	  the application support it.  When this feature is enabled,
+	  legacy non-IBT applications continue to work, but without
+	  IBT protection.
+	  Support for this feature is only known to be present on
+	  processors released in 2020 or later.  CET features are also
+	  known to increase kernel text size by 3.7 KB.
+
+	  If unsure, say N.
+
 config EFI
 	bool "EFI runtime service support"
 	depends on ACPI