[PATCH v3 3/3] integer-wrap: Force full rebuild when .scl file changes

Kees Cook
2025-05-03T18:46:26Z

Since the integer wrapping sanitizer's behavior depends on its associated
.scl file, we must force a full rebuild if the file changes. If not,
instrumentation may differ between targets based on when they were built.

Generate a new header file, integer-wrap.h, any time the Clang .scl
file changes. Include the header file in compiler-version.h when its
associated feature name, INTEGER_WRAP, is defined. This will be picked
up by fixdep and force rebuilds where needed.

Signed-off-by: Kees Cook <kees@kernel.org>
---
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas.schier@linux.dev>
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: <linux-kbuild@vger.kernel.org>
Cc: <kasan-dev@googlegroups.com>
Cc: <linux-hardening@vger.kernel.org>
---
include/linux/compiler-version.h | 3 +++
scripts/Makefile.ubsan | 1 +
scripts/basic/Makefile | 5 +++++
3 files changed, 9 insertions(+)

diff --git a/include/linux/compiler-version.h b/include/linux/compiler-version.h
index 69b29b400ce2..187e749f9e79 100644
--- a/include/linux/compiler-version.h
+++ b/include/linux/compiler-version.h
@@ -19,3 +19,6 @@
#ifdef RANDSTRUCT
#include <generated/randstruct_hash.h>
#endif
+#ifdef INTEGER_WRAP
+#include <generated/integer-wrap.h>
+#endif
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
index 9e35198edbf0..653f7117819c 100644
--- a/scripts/Makefile.ubsan
+++ b/scripts/Makefile.ubsan
@@ -15,6 +15,7 @@ ubsan-cflags-$(CONFIG_UBSAN_TRAP) += $(call cc-option,-fsanitize-trap=undefined
export CFLAGS_UBSAN := $(ubsan-cflags-y)

ubsan-integer-wrap-cflags-$(CONFIG_UBSAN_INTEGER_WRAP) += \
+ -DINTEGER_WRAP \
-fsanitize-undefined-ignore-overflow-pattern=all \
-fsanitize=signed-integer-overflow \
-fsanitize=unsigned-integer-overflow \
diff --git a/scripts/basic/Makefile b/scripts/basic/Makefile
index dd289a6725ac..fb8e2c38fbc7 100644
--- a/scripts/basic/Makefile
+++ b/scripts/basic/Makefile
@@ -14,3 +14,8 @@ cmd_create_randstruct_seed = \
$(obj)/randstruct.seed: $(gen-randstruct-seed) FORCE
$(call if_changed,create_randstruct_seed)
always-$(CONFIG_RANDSTRUCT) += randstruct.seed
+
+# integer-wrap: if the .scl file changes, we need to do a full rebuild.
+$(obj)/../../include/generated/integer-wrap.h: $(srctree)/scripts/integer-wrap-ignore.scl FORCE
+ $(call if_changed,touch)
+always-$(CONFIG_UBSAN_INTEGER_WRAP) += ../../include/generated/integer-wrap.h
--
2.34.1