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-rw-r--r--arch/Kconfig45
1 files changed, 45 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig
index ecfd3520b676..f6a85ba6cba2 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -692,6 +692,51 @@ config LTO_CLANG_THIN
If unsure, say Y.
endchoice
+config ARCH_SUPPORTS_CFI_CLANG
+ bool
+ help
+ An architecture should select this option if it can support Clang's
+ Control-Flow Integrity (CFI) checking.
+
+config CFI_CLANG
+ bool "Use Clang's Control Flow Integrity (CFI)"
+ depends on LTO_CLANG && ARCH_SUPPORTS_CFI_CLANG
+ # Clang >= 12:
+ # - https://bugs.llvm.org/show_bug.cgi?id=46258
+ # - https://bugs.llvm.org/show_bug.cgi?id=47479
+ depends on CLANG_VERSION >= 120000
+ select KALLSYMS
+ help
+ This option enables Clang’s forward-edge Control Flow Integrity
+ (CFI) checking, where the compiler injects a runtime check to each
+ indirect function call to ensure the target is a valid function with
+ the correct static type. This restricts possible call targets and
+ makes it more difficult for an attacker to exploit bugs that allow
+ the modification of stored function pointers. More information can be
+ found from Clang's documentation:
+
+ https://clang.llvm.org/docs/ControlFlowIntegrity.html
+
+config CFI_CLANG_SHADOW
+ bool "Use CFI shadow to speed up cross-module checks"
+ default y
+ depends on CFI_CLANG && MODULES
+ help
+ If you select this option, the kernel builds a fast look-up table of
+ CFI check functions in loaded modules to reduce performance overhead.
+
+ If unsure, say Y.
+
+config CFI_PERMISSIVE
+ bool "Use CFI in permissive mode"
+ depends on CFI_CLANG
+ help
+ When selected, Control Flow Integrity (CFI) violations result in a
+ warning instead of a kernel panic. This option should only be used
+ for finding indirect call type mismatches during development.
+
+ If unsure, say N.
+
config HAVE_ARCH_WITHIN_STACK_FRAMES
bool
help

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