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From: Kees Cook <keescook@chromium.org>
To: Marco Elver <elver@google.com>
Cc: Kees Cook <keescook@chromium.org>,
	kernel test robot <lkp@intel.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	kasan-dev@googlegroups.com,
	linux-hardening@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] ubsan: Disable signed integer overflow sanitizer on GCC < 8
Date: Wed, 13 Mar 2024 11:12:20 -0700
Message-Id: <20240313181217.work.263-kees@kernel.org>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit

For opting functions out of sanitizer coverage, the "no_sanitize"
attribute is used, but in GCC this wasn't introduced until GCC 8.
Disable the sanitizer unless we're not using GCC, or it is GCC
version 8 or higher.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202403110643.27JXEVCI-lkp@intel.com/
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Cc: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: kasan-dev@googlegroups.com
Cc: linux-hardening@vger.kernel.org
---
 lib/Kconfig.ubsan | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 48a67058f84e..e81e1ac4a919 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -119,6 +119,8 @@ config UBSAN_SIGNED_WRAP
 	bool "Perform checking for signed arithmetic wrap-around"
 	default UBSAN
 	depends on !COMPILE_TEST
+	# The no_sanitize attribute was introduced in GCC with version 8.
+	depends on !CC_IS_GCC || GCC_VERSION >= 80000
 	depends on $(cc-option,-fsanitize=signed-integer-overflow)
 	help
 	  This option enables -fsanitize=signed-integer-overflow which checks
-- 
2.34.1