[PATCH 4/6] randstruct: Split randstruct Makefile and CFLAGS
From: Kees Cook
Date: Tue May 03 2022 - 16:55:44 EST
To enable the new Clang randstruct implementation[1], move
randstruct into its own Makefile and split the CFLAGS from
GCC_PLUGINS_CFLAGS into RANDSTRUCT_CFLAGS.
[1] https://reviews.llvm.org/D121556
Cc: linux-hardening@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Makefile | 1 +
arch/arm/vdso/Makefile | 2 +-
arch/arm64/kernel/vdso/Makefile | 3 ++-
arch/sparc/vdso/Makefile | 3 ++-
arch/x86/entry/vdso/Makefile | 3 ++-
scripts/Makefile.gcc-plugins | 8 ++------
scripts/Makefile.randstruct | 14 ++++++++++++++
7 files changed, 24 insertions(+), 10 deletions(-)
create mode 100644 scripts/Makefile.randstruct
diff --git a/Makefile b/Makefile
index 29e273d3f8cc..91c91fcf3c24 100644
--- a/Makefile
+++ b/Makefile
@@ -1011,6 +1011,7 @@ include-$(CONFIG_KASAN) += scripts/Makefile.kasan
include-$(CONFIG_KCSAN) += scripts/Makefile.kcsan
include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan
include-$(CONFIG_KCOV) += scripts/Makefile.kcov
+include-$(CONFIG_RANDSTRUCT) += scripts/Makefile.randstruct
include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins
include $(addprefix $(srctree)/, $(include-y))
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile
index ec52b776f926..8ca1c9f262a2 100644
--- a/arch/arm/vdso/Makefile
+++ b/arch/arm/vdso/Makefile
@@ -28,7 +28,7 @@ CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
CFLAGS_REMOVE_vdso.o = -pg
# Force -O2 to avoid libgcc dependencies
-CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(GCC_PLUGINS_CFLAGS)
+CFLAGS_REMOVE_vgettimeofday.o = -pg -Os $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS)
ifeq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o = -O2
else
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index 172452f79e46..d9147fba1a0b 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -32,7 +32,8 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
# -Wmissing-prototypes and -Wmissing-declarations are removed from
# the CFLAGS of vgettimeofday.c to make possible to build the
# kernel with CONFIG_WERROR enabled.
-CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) $(GCC_PLUGINS_CFLAGS) \
+CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) \
+ $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) \
$(CC_FLAGS_LTO) -Wmissing-prototypes -Wmissing-declarations
KASAN_SANITIZE := n
KCSAN_SANITIZE := n
diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile
index c5e1545bc5cf..77d7b9032158 100644
--- a/arch/sparc/vdso/Makefile
+++ b/arch/sparc/vdso/Makefile
@@ -58,7 +58,7 @@ CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64
SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 -fcall-used-g5 -fcall-used-g7
-$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
+$(vobjs): KBUILD_CFLAGS := $(filter-out $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
#
# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
@@ -88,6 +88,7 @@ $(obj)/vdso32.so.dbg: asflags-$(CONFIG_SPARC64) += -m32
KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_32 := $(filter-out -mcmodel=medlow,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 693f8b9031fb..c2a8b76ae0bc 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -91,7 +91,7 @@ ifneq ($(RETPOLINE_VDSO_CFLAGS),)
endif
endif
-$(vobjs): KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
+$(vobjs): KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_LTO) $(RANDSTRUCT_CFLAGS) $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
#
# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
@@ -148,6 +148,7 @@ KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 := $(filter-out $(RANDSTRUCT_CFLAGS),$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS_32))
KBUILD_CFLAGS_32 := $(filter-out $(CC_FLAGS_LTO),$(KBUILD_CFLAGS_32))
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 827c47ce5c73..692d64a70542 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -22,12 +22,6 @@ export DISABLE_STRUCTLEAK_PLUGIN
gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) \
+= -DSTRUCTLEAK_PLUGIN
-gcc-plugin-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) += randomize_layout_plugin.so
-gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) \
- += -DRANDSTRUCT
-gcc-plugin-cflags-$(CONFIG_RANDSTRUCT_PERFORMANCE) \
- += -fplugin-arg-randomize_layout_plugin-performance-mode
-
gcc-plugin-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak_plugin.so
gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STACKLEAK) \
+= -DSTACKLEAK_PLUGIN
@@ -60,6 +54,8 @@ KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS)
# be included in GCC_PLUGIN so they can get built.
gcc-plugin-external-$(CONFIG_GCC_PLUGIN_SANCOV) \
+= sancov_plugin.so
+gcc-plugin-external-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) \
+ += randomize_layout_plugin.so
# All enabled GCC plugins are collected here for building in
# scripts/gcc-scripts/Makefile.
diff --git a/scripts/Makefile.randstruct b/scripts/Makefile.randstruct
new file mode 100644
index 000000000000..4d741e6db554
--- /dev/null
+++ b/scripts/Makefile.randstruct
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+
+randstruct-cflags-y += -DRANDSTRUCT
+
+ifdef CONFIG_GCC_PLUGIN_RANDSTRUCT
+randstruct-cflags-y \
+ += -fplugin=$(objtree)/scripts/gcc-plugins/randomize_layout_plugin.so
+randstruct-cflags-$(CONFIG_RANDSTRUCT_PERFORMANCE) \
+ += -fplugin-arg-randomize_layout_plugin-performance-mode
+endif
+
+export RANDSTRUCT_CFLAGS := $(randstruct-cflags-y)
+
+KBUILD_CFLAGS += $(RANDSTRUCT_CFLAGS)
--
2.32.0