randstruct: Split randstruct Makefile and CFLAGS

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@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-5-keescook@chromium.org

diff --git a/Makefile b/Makefile
index 29e273d..91c91fc 100644 (file)
--- 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 ec52b77..8ca1c9f 100644 (file)
--- 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 172452f..d9147fb 100644 (file)
--- 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 c5e1545..77d7b90 100644 (file)
--- 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 693f8b9..c2a8b76 100644 (file)
--- 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 827c47c..692d64a 100644 (file)
--- 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 (file)
index 0000000..4d741e6
--- /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)