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From: Kees Cook <keescook@chromium.org>
To: Kees Cook <keescook@chromium.org>
Cc: Nathan Chancellor <nathan@kernel.org>,
	llvm@lists.linux.dev, Miguel Ojeda <ojeda@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	George Burgess IV <gbiv@google.com>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH v7 3/8] Compiler Attributes: Add __overloadable for Clang
Date: Tue,  8 Feb 2022 14:53:45 -0800	[thread overview]
Message-ID: <20220208225350.1331628-4-keescook@chromium.org> (raw)
In-Reply-To: <20220208225350.1331628-1-keescook@chromium.org>

In order for FORTIFY_SOURCE to use __pass_object_size on an "extern
inline" function, as all the fortified string functions are, the functions
must be marked as being overloadable (i.e. different prototypes due
to the implicitly injected object size arguments). This allows the
__pass_object_size versions to take precedence.

Cc: Nathan Chancellor <nathan@kernel.org>
Cc: llvm@lists.linux.dev
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 include/linux/compiler_attributes.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/compiler_attributes.h b/include/linux/compiler_attributes.h
index d0c503772061..dcaf55f5d1ae 100644
--- a/include/linux/compiler_attributes.h
+++ b/include/linux/compiler_attributes.h
@@ -257,6 +257,18 @@
  */
 #define __noreturn                      __attribute__((__noreturn__))
 
+/*
+ * Optional: not supported by gcc.
+ * Optional: not supported by icc.
+ *
+ * clang: https://clang.llvm.org/docs/AttributeReference.html#overloadable
+ */
+#if __has_attribute(__overloadable__)
+# define __overloadable			__attribute__((__overloadable__))
+#else
+# define __overloadable
+#endif
+
 /*
  *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-packed-type-attribute
  * clang: https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-packed-variable-attribute
-- 
2.30.2


  parent reply	other threads:[~2022-02-08 22:53 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-08 22:53 [PATCH v7 0/8] fortify: Add Clang support Kees Cook
2022-02-08 22:53 ` [PATCH v7 1/8] fortify: Replace open-coded __gnu_inline attribute Kees Cook
2022-02-08 22:59   ` Nick Desaulniers
2022-02-08 22:53 ` [PATCH v7 2/8] Compiler Attributes: Add __pass_object_size for Clang Kees Cook
2022-02-08 23:00   ` Nick Desaulniers
2022-02-08 22:53 ` Kees Cook [this message]
2022-02-08 22:53 ` [PATCH v7 4/8] Compiler Attributes: Add __diagnose_as " Kees Cook
2022-02-08 22:53 ` [PATCH v7 5/8] fortify: Make pointer arguments const Kees Cook
2022-02-08 23:02   ` Nick Desaulniers
2022-02-08 22:53 ` [PATCH v7 6/8] fortify: Use __diagnose_as() for better diagnostic coverage Kees Cook
2022-02-08 23:04   ` Nick Desaulniers
2022-02-08 22:53 ` [PATCH v7 7/8] fortify: Make sure strlen() may still be used as a constant expression Kees Cook
2022-02-08 23:17   ` Nick Desaulniers
2022-02-08 23:58     ` Kees Cook
2022-02-08 22:53 ` [PATCH v7 8/8] fortify: Add Clang support Kees Cook
2022-02-08 23:25   ` Nick Desaulniers

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