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From: Kees Cook <keescook@chromium.org>
To: Kees Cook <keescook@chromium.org>
Cc: Miguel Ojeda <ojeda@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Nathan Chancellor <nathan@kernel.org>,
	llvm@lists.linux.dev, George Burgess IV <gbiv@google.com>,
	linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH v6 2/4] Compiler Attributes: Add __overloadable for Clang
Date: Thu,  3 Feb 2022 09:33:05 -0800	[thread overview]
Message-ID: <20220203173307.1033257-3-keescook@chromium.org> (raw)
In-Reply-To: <20220203173307.1033257-1-keescook@chromium.org>

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

Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: llvm@lists.linux.dev
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 4ce370094e3a..dc3bf2a6e1c9 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:[~2022-02-03 17:33 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-03 17:33 [PATCH v6 0/4] fortify: Add Clang support Kees Cook
2022-02-03 17:33 ` [PATCH v6 1/4] Compiler Attributes: Add __pass_object_size for Clang Kees Cook
2022-02-03 20:18   ` Nick Desaulniers
2022-02-03 20:58     ` Kees Cook
2022-02-03 22:01       ` Nick Desaulniers
2022-02-04  0:29         ` Kees Cook
2022-02-03 17:33 ` Kees Cook [this message]
2022-02-03 20:26   ` [PATCH v6 2/4] Compiler Attributes: Add __overloadable " Nick Desaulniers
2022-02-03 21:04     ` Kees Cook
2022-02-03 22:11       ` Nick Desaulniers
2022-02-04  0:26         ` Kees Cook
2022-02-04  0:58           ` Nick Desaulniers
2022-02-04  1:07       ` Miguel Ojeda
2022-02-03 17:33 ` [PATCH v6 3/4] Compiler Attributes: Add __diagnose_as " Kees Cook
2022-02-03 20:28   ` Nick Desaulniers
2022-02-03 17:33 ` [PATCH v6 4/4] fortify: Add Clang support Kees Cook
2022-02-03 20:37   ` Nick Desaulniers
2022-02-03 21:26     ` Kees Cook
2022-02-03 17:47 ` [PATCH v6 0/4] " Miguel Ojeda
2022-02-03 19:57   ` Kees Cook
2022-02-03 21:12     ` Miguel Ojeda

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