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From: Kees Cook <kees@kernel.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: Kees Cook <kees@kernel.org>,
	Kent Overstreet <kent.overstreet@linux.dev>,
	Andy Shevchenko <andy@kernel.org>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Philipp Reisner <philipp.reisner@linbit.com>,
	Miguel Ojeda <ojeda@kernel.org>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH 1/3] compiler.h: Move C string helpers into C-only kernel section
Date: Thu,  6 Feb 2025 10:11:28 -0800	[thread overview]
Message-ID: <20250206181133.3450635-1-kees@kernel.org> (raw)
In-Reply-To: <20250206175216.work.225-kees@kernel.org>

The C kernel helpers for evaluating C Strings were placed outside of the
assembly ifdef. Move them to the correct place 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")
Signed-off-by: Kees Cook <kees@kernel.org>
---
 include/linux/compiler.h | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 240c632c5b95..7af999a131cb 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.
-- 
2.34.1


  reply	other threads:[~2025-02-06 18:11 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-06 18:11 [PATCH 0/3] string.h: Use ARRAY_SIZE() for memtostr*()/strtomem*() Kees Cook
2025-02-06 18:11 ` Kees Cook [this message]
2025-02-06 20:07   ` [PATCH 1/3] compiler.h: Move C string helpers into C-only kernel section Miguel Ojeda
2025-02-06 21:28     ` Kees Cook
2025-02-06 18:11 ` [PATCH 2/3] compiler.h: Introduce __must_be_char_array() Kees Cook
2025-02-06 19:56   ` David Laight
2025-02-06 21:34     ` Kees Cook
2025-02-06 20:50   ` Kent Overstreet
2025-02-06 21:26     ` Kees Cook
2025-02-07  8:55   ` Rasmus Villemoes
2025-02-07 13:13     ` David Laight
2025-02-07 13:58   ` Kent Overstreet
2025-02-06 18:11 ` [PATCH 3/3] string.h: Use ARRAY_SIZE() for memtostr*()/strtomem*() Kees Cook
2025-02-06 18:41 ` [PATCH 0/3] " Andy Shevchenko
2025-02-06 18:44   ` Miguel Ojeda
2025-02-06 18:45     ` Andy Shevchenko
2025-02-06 18:52       ` Kees Cook
2025-02-06 19:12         ` Andy Shevchenko

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