init: Kconfig: Disable -Wstringop-overflow for GCC-11
-Wstringop-overflow is buggy in GCC-11. Therefore, we should disable
this option specifically for that compiler version. To achieve this,
we introduce a new configuration option: GCC11_NO_STRINGOP_OVERFLOW.
The compiler option related to string operation overflow is now managed
under configuration CC_STRINGOP_OVERFLOW. This option is enabled by
default for all other versions of GCC that support it.
Link: https://lore.kernel.org/lkml/b3c99290-40bc-426f-b3d2-1aa903f95c4e@embeddedor.com/
Link: https://lore.kernel.org/lkml/20231128091351.2bfb38dd@canb.auug.org.au/
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/linux-hardening/ZWj1+jkweEDWbmAR@work/
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
diff --git a/Makefile b/Makefile
index c01cbbb..9f9b76d 100644
--- a/Makefile
+++ b/Makefile
@@ -986,7 +986,9 @@
# perform bounds checking.
KBUILD_CFLAGS += $(call cc-option, -fstrict-flex-arrays=3)
-KBUILD_CFLAGS += $(call cc-option, -Wstringop-overflow)
+#Currently, disable -Wstringop-overflow for GCC 11, globally.
+KBUILD_CFLAGS-$(CONFIG_CC_NO_STRINGOP_OVERFLOW) += $(call cc-option, -Wno-stringop-overflow)
+KBUILD_CFLAGS-$(CONFIG_CC_STRINGOP_OVERFLOW) += $(call cc-option, -Wstringop-overflow)
# disable invalid "can't wrap" optimizations for signed / pointers
KBUILD_CFLAGS += -fno-strict-overflow
diff --git a/init/Kconfig b/init/Kconfig
index 8df18f3..8d4e836 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -876,6 +876,18 @@
bool
default y if CC_IS_GCC && GCC_VERSION >= 110000 && GCC11_NO_ARRAY_BOUNDS
+# Currently, disable -Wstringop-overflow for GCC 11, globally.
+config GCC11_NO_STRINGOP_OVERFLOW
+ def_bool y
+
+config CC_NO_STRINGOP_OVERFLOW
+ bool
+ default y if CC_IS_GCC && GCC_VERSION >= 110000 && GCC_VERSION < 120000 && GCC11_NO_STRINGOP_OVERFLOW
+
+config CC_STRINGOP_OVERFLOW
+ bool
+ default y if CC_IS_GCC && !CC_NO_STRINGOP_OVERFLOW
+
#
# For architectures that know their GCC __int128 support is sound
#
