Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 543c37cb authored by Emese Revfy's avatar Emese Revfy Committed by Michal Marek
Browse files

Add sancov plugin 

The sancov gcc plugin inserts a __sanitizer_cov_trace_pc() call
at the start of basic blocks.

This plugin is a helper plugin for the kcov feature. It supports
all gcc versions with plugin support (from gcc-4.5 on).
It is based on the gcc commit "Add fuzzing coverage support" by Dmitry Vyukov
(https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296

).

Signed-off-by: default avatarEmese Revfy <re.emese@gmail.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarMichal Marek <mmarek@suse.com>
parent 0dae776c

Makefile

+1 −9
Original line number Diff line number Diff line
@@ -369,7 +369,7 @@ LDFLAGS_MODULE = 
CFLAGS_KERNEL	=

AFLAGS_KERNEL	=

CFLAGS_GCOV	= -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized

CFLAGS_KCOV	= -fsanitize-coverage=trace-pc

CFLAGS_KCOV	:= $(call cc-option,-fsanitize-coverage=trace-pc,)





# Use USERINCLUDE when you must reference the UAPI directories only.
@@ -691,14 +691,6 @@ endif 
endif

KBUILD_CFLAGS += $(stackp-flag)



ifdef CONFIG_KCOV

  ifeq ($(call cc-option, $(CFLAGS_KCOV)),)

    $(warning Cannot use CONFIG_KCOV: \

             -fsanitize-coverage=trace-pc is not supported by compiler)

    CFLAGS_KCOV =

  endif

endif



ifeq ($(cc-name),clang)

KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)

KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,)

arch/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -384,6 +384,15 @@ config GCC_PLUGIN_CYC_COMPLEXITY 
	  N = the number of nodes

	  P = the number of connected components (exit nodes).



config GCC_PLUGIN_SANCOV

	bool

	depends on GCC_PLUGINS

	help

	  This plugin inserts a __sanitizer_cov_trace_pc() call at the start of

	  basic blocks. It supports all gcc versions with plugin support (from

	  gcc-4.5 on). It is based on the commit "Add fuzzing coverage support"

	  by Dmitry Vyukov <dvyukov@google.com>.



config HAVE_CC_STACKPROTECTOR

	bool

	help

arch/x86/purgatory/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ PURGATORY_OBJS = $(addprefix $(obj)/,$(purgatory-y)) 
LDFLAGS_purgatory.ro := -e purgatory_start -r --no-undefined -nostdlib -z nodefaultlib

targets += purgatory.ro



KCOV_INSTRUMENT := n



# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That

# in turn leaves some undefined symbols like __fentry__ in purgatory and not

# sure how to relocate those. Like kexec-tools, use custom flags.

lib/Kconfig.debug

+2 −0
Original line number Diff line number Diff line
@@ -708,6 +708,8 @@ config KCOV 
	bool "Code coverage for fuzzing"

	depends on ARCH_HAS_KCOV

	select DEBUG_FS

	select GCC_PLUGINS

	select GCC_PLUGIN_SANCOV

	help

	  KCOV exposes kernel code coverage information in a form suitable

	  for coverage-guided fuzzing (randomized testing).

scripts/Makefile.gcc-plugins

+20 −1
Original line number Diff line number Diff line
@@ -2,10 +2,26 @@ ifdef CONFIG_GCC_PLUGINS 
  __PLUGINCC := $(call cc-ifversion, -ge, 0408, $(HOSTCXX), $(HOSTCC))

  PLUGINCC := $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-plugin.sh "$(__PLUGINCC)" "$(HOSTCXX)" "$(CC)")



  SANCOV_PLUGIN := -fplugin=$(objtree)/scripts/gcc-plugins/sancov_plugin.so



  gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY)	+= cyc_complexity_plugin.so



  ifdef CONFIG_GCC_PLUGIN_SANCOV

    ifeq ($(CFLAGS_KCOV),)

      # It is needed because of the gcc-plugin.sh and gcc version checks.

      gcc-plugin-$(CONFIG_GCC_PLUGIN_SANCOV)           += sancov_plugin.so



      ifneq ($(PLUGINCC),)

        CFLAGS_KCOV := $(SANCOV_PLUGIN)

      else

        $(warning warning: cannot use CONFIG_KCOV: -fsanitize-coverage=trace-pc is not supported by compiler)

      endif

    endif

  endif



  GCC_PLUGINS_CFLAGS := $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y))



  export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN

  export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN SANCOV_PLUGIN



  ifeq ($(PLUGINCC),)

    ifneq ($(GCC_PLUGINS_CFLAGS),)
@@ -16,6 +32,9 @@ ifdef CONFIG_GCC_PLUGINS 
        $(warning warning: your gcc version does not support plugins, you should upgrade it to gcc 4.5 at least)

      endif

    endif

  else

    # SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication.

    GCC_PLUGINS_CFLAGS := $(filter-out $(SANCOV_PLUGIN), $(GCC_PLUGINS_CFLAGS))

  endif



  KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS)