[PATCH v14 1/7] x86/cet/ibt: Add Kconfig option for user-mode Indirect Branch Tracking

Yu-cheng Yu
2020-10-12T15:45:55Z

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>
---
arch/x86/Kconfig | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

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
--
2.21.0