From 0bb95f80a38f82884693194ea720e9cca5e12ada Mon Sep 17 00:00:00 2001 From: Kees Cook <keescook@chromium.org> Date: Mon, 25 Jun 2018 15:59:34 -0700 Subject: [PATCH] Makefile: Globally enable VLA warning Now that Variable Length Arrays (VLAs) have been entirely removed[1] from the kernel, enable the VLA warning globally. The only exceptions to this are the KASan an UBSan tests which are explicitly checking that VLAs trigger their respective tests. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: David Airlie <airlied@linux.ie> Cc: linux-kbuild@vger.kernel.org Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: Kees Cook <keescook@chromium.org> --- Makefile | 3 +++ drivers/gpu/drm/i915/Makefile | 2 +- lib/Makefile | 2 ++ scripts/Makefile.extrawarn | 1 - 4 files changed, 6 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 19948e5569413..f1760e8db5732 100644 --- a/Makefile +++ b/Makefile @@ -804,6 +804,9 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include) # warn about C99 declaration after statement KBUILD_CFLAGS += $(call cc-option,-Wdeclaration-after-statement,) +# Variable Length Arrays (VLAs) should not be used anywhere in the kernel +KBUILD_CFLAGS += $(call cc-option,-Wvla) + # disable pointer signed / unsigned warnings in gcc 4.0 KBUILD_CFLAGS += $(call cc-disable-warning, pointer-sign) diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile index 5794f102f9b8f..1c2857f13ad43 100644 --- a/drivers/gpu/drm/i915/Makefile +++ b/drivers/gpu/drm/i915/Makefile @@ -12,7 +12,7 @@ # Note the danger in using -Wall -Wextra is that when CI updates gcc we # will most likely get a sudden build breakage... Hopefully we will fix # new warnings before CI updates! -subdir-ccflags-y := -Wall -Wextra -Wvla +subdir-ccflags-y := -Wall -Wextra subdir-ccflags-y += $(call cc-disable-warning, unused-parameter) subdir-ccflags-y += $(call cc-disable-warning, type-limits) subdir-ccflags-y += $(call cc-disable-warning, missing-field-initializers) diff --git a/lib/Makefile b/lib/Makefile index ca3f7ebb900d8..8e0aca8a2f099 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -53,7 +53,9 @@ obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o obj-$(CONFIG_TEST_IDA) += test_ida.o obj-$(CONFIG_TEST_KASAN) += test_kasan.o CFLAGS_test_kasan.o += -fno-builtin +CFLAGS_test_kasan.o += $(call cc-disable-warning, vla) obj-$(CONFIG_TEST_UBSAN) += test_ubsan.o +CFLAGS_test_ubsan.o += $(call cc-disable-warning, vla) UBSAN_SANITIZE_test_ubsan.o := y obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o obj-$(CONFIG_TEST_LIST_SORT) += test_list_sort.o diff --git a/scripts/Makefile.extrawarn b/scripts/Makefile.extrawarn index 8d5357053f865..24b2fb1d12974 100644 --- a/scripts/Makefile.extrawarn +++ b/scripts/Makefile.extrawarn @@ -52,7 +52,6 @@ warning-3 += -Wpointer-arith warning-3 += -Wredundant-decls warning-3 += -Wswitch-default warning-3 += $(call cc-option, -Wpacked-bitfield-compat) -warning-3 += $(call cc-option, -Wvla) warning := $(warning-$(findstring 1, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) warning += $(warning-$(findstring 2, $(KBUILD_ENABLE_EXTRA_GCC_CHECKS))) -- GitLab