This is a note to let you know that I've just added the patch titled
compiler.h: Move C string helpers into C-only kernel section
to the 6.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
compiler.h-move-c-string-helpers-into-c-only-kernel-.patch
and it can be found in the queue-6.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6ebc76bf95d6ec3b958b501d6fce71f85ef2d576
Author: Kees Cook <kees@xxxxxxxxxx>
Date: Wed Feb 5 12:32:49 2025 -0800
compiler.h: Move C string helpers into C-only kernel section
[ Upstream commit cb7380de9e4cbc9a24216b722ec50e092ae83036 ]
The C kernel helpers for evaluating C Strings were positioned where they
were visible to assembly inclusion, which was not intended. Move them
into the kernel and C-only area of the header so future changes won't
confuse the assembler.
Fixes: d7a516c6eeae ("compiler.h: Fix undefined BUILD_BUG_ON_ZERO()")
Fixes: 559048d156ff ("string: Check for "nonstring" attribute on strscpy() arguments")
Reviewed-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
Signed-off-by: Kees Cook <kees@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 240c632c5b957..7af999a131cb2 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -214,6 +214,19 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
__v; \
})
+#ifdef __CHECKER__
+#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)
+#else /* __CHECKER__ */
+#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
+#endif /* __CHECKER__ */
+
+/* &a[0] degrades to a pointer: a different type from an array */
+#define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(__same_type((a), &(a)[0]), "must be array")
+
+/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */
+#define __must_be_cstr(p) \
+ __BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")
+
#endif /* __KERNEL__ */
/**
@@ -254,19 +267,6 @@ static inline void *offset_to_ptr(const int *off)
#define __ADDRESSABLE_ASM_STR(sym) __stringify(__ADDRESSABLE_ASM(sym))
-#ifdef __CHECKER__
-#define __BUILD_BUG_ON_ZERO_MSG(e, msg) (0)
-#else /* __CHECKER__ */
-#define __BUILD_BUG_ON_ZERO_MSG(e, msg) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
-#endif /* __CHECKER__ */
-
-/* &a[0] degrades to a pointer: a different type from an array */
-#define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(__same_type((a), &(a)[0]), "must be array")
-
-/* Require C Strings (i.e. NUL-terminated) lack the "nonstring" attribute. */
-#define __must_be_cstr(p) \
- __BUILD_BUG_ON_ZERO_MSG(__annotated(p, nonstring), "must be cstr (NUL-terminated)")
-
/*
* This returns a constant expression while determining if an argument is
* a constant expression, most importantly without evaluating the argument.
