From 552a23a0e5d0a84cecd4687043d8030673981d30 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 29 Sep 2021 16:18:03 -0500 Subject: [PATCH] Makefile: Enable -Wcast-function-type In order to make sure new function cast mismatches are not introduced in the kernel (to avoid tripping CFI checking), the kernel should be globally built with -Wcast-function-type. Link: https://github.com/KSPP/linux/issues/20 Co-developed-by: Kees Cook Signed-off-by: Kees Cook Signed-off-by: Gustavo A. R. Silva --- Makefile | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Makefile b/Makefile index 9e12c14ea0fbb2..5a8cde6a2fbb45 100644 --- a/Makefile +++ b/Makefile @@ -953,6 +953,11 @@ KBUILD_CFLAGS += -Wvla # disable pointer signed / unsigned warnings in gcc 4.0 KBUILD_CFLAGS += -Wno-pointer-sign +# In order to make sure new function cast mismatches are not introduced +# in the kernel (to avoid tripping CFI checking), the kernel should be +# globally built with -Wcast-function-type. +KBUILD_CFLAGS += $(call cc-option, -Wcast-function-type) + # disable stringop warnings in gcc 8+ KBUILD_CFLAGS += $(call cc-disable-warning, stringop-truncation)