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authorSami Tolvanen <samitolvanen@google.com>2022-09-08 14:54:47 -0700
committerKees Cook <keescook@chromium.org>2022-09-26 10:13:13 -0700
commit89245600941e4e0f87d77f60ee269b5e61ef4e49 (patch)
treea0069b5bd625907cb854091e6dbbeed4964815b0 /include/linux/compiler-clang.h
parent92efda8eb15295a07f450828b2db14485bfc09c2 (diff)
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cfi: Switch to -fsanitize=kcfi
Switch from Clang's original forward-edge control-flow integrity implementation to -fsanitize=kcfi, which is better suited for the kernel, as it doesn't require LTO, doesn't use a jump table that requires altering function references, and won't break cross-module function address equality. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220908215504.3686827-6-samitolvanen@google.com
Diffstat (limited to 'include/linux/compiler-clang.h')
-rw-r--r--include/linux/compiler-clang.h14
1 files changed, 3 insertions, 11 deletions
diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
index c84fec767445..42e55579d649 100644
--- a/include/linux/compiler-clang.h
+++ b/include/linux/compiler-clang.h
@@ -66,17 +66,9 @@
# define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
#endif
-#define __nocfi __attribute__((__no_sanitize__("cfi")))
-#define __cficanonical __attribute__((__cfi_canonical_jump_table__))
-
-#if defined(CONFIG_CFI_CLANG)
-/*
- * With CONFIG_CFI_CLANG, the compiler replaces function address
- * references with the address of the function's CFI jump table
- * entry. The function_nocfi macro always returns the address of the
- * actual function instead.
- */
-#define function_nocfi(x) __builtin_function_start(x)
+#if __has_feature(kcfi)
+/* Disable CFI checking inside a function. */
+#define __nocfi __attribute__((__no_sanitize__("kcfi")))
#endif
/*