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![Ard Biesheuvel](/assets/img/avatar_default.png)
In the Linux kernel, struct type variables are rarely passed by-value, and so functions that initialize such variables typically take an input reference to the variable rather than returning a value that can subsequently be used in an assignment. If the initalization function is not part of the same compilation unit, the lack of an assignment operation defeats any analysis the compiler can perform as to whether the variable may be used before having been initialized. This means we may end up passing on such variables uninitialized, resulting in potential information leaks. So extend the existing structleak GCC plugin so it will [optionally] apply to all struct type variables that have their address taken at any point, rather than only to variables of struct types that have a __user annotation. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Kees Cook <keescook@chromium.org>
84 lines
3.5 KiB
Makefile
84 lines
3.5 KiB
Makefile
ifdef CONFIG_GCC_PLUGINS
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__PLUGINCC := $(call cc-ifversion, -ge, 0408, $(HOSTCXX), $(HOSTCC))
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PLUGINCC := $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-plugin.sh "$(__PLUGINCC)" "$(HOSTCXX)" "$(CC)")
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SANCOV_PLUGIN := -fplugin=$(objtree)/scripts/gcc-plugins/sancov_plugin.so
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gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) += cyc_complexity_plugin.so
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gcc-plugin-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) += latent_entropy_plugin.so
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) += -DLATENT_ENTROPY_PLUGIN
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ifdef CONFIG_GCC_PLUGIN_LATENT_ENTROPY
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DISABLE_LATENT_ENTROPY_PLUGIN += -fplugin-arg-latent_entropy_plugin-disable
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endif
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ifdef CONFIG_GCC_PLUGIN_SANCOV
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ifeq ($(CFLAGS_KCOV),)
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# It is needed because of the gcc-plugin.sh and gcc version checks.
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gcc-plugin-$(CONFIG_GCC_PLUGIN_SANCOV) += sancov_plugin.so
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ifneq ($(PLUGINCC),)
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CFLAGS_KCOV := $(SANCOV_PLUGIN)
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else
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$(warning warning: cannot use CONFIG_KCOV: -fsanitize-coverage=trace-pc is not supported by compiler)
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endif
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endif
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endif
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gcc-plugin-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += structleak_plugin.so
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE) += -fplugin-arg-structleak_plugin-verbose
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL) += -fplugin-arg-structleak_plugin-byref-all
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += -DSTRUCTLEAK_PLUGIN
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gcc-plugin-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) += randomize_layout_plugin.so
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) += -DRANDSTRUCT_PLUGIN
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gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE) += -fplugin-arg-randomize_layout_plugin-performance-mode
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GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y))
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export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR
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export SANCOV_PLUGIN DISABLE_LATENT_ENTROPY_PLUGIN
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ifneq ($(PLUGINCC),)
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# SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication.
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GCC_PLUGINS_CFLAGS := $(filter-out $(SANCOV_PLUGIN), $(GCC_PLUGINS_CFLAGS))
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endif
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KBUILD_CFLAGS += $(GCC_PLUGINS_CFLAGS)
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GCC_PLUGIN := $(gcc-plugin-y)
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GCC_PLUGIN_SUBDIR := $(gcc-plugin-subdir-y)
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endif
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# If plugins aren't supported, abort the build before hard-to-read compiler
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# errors start getting spewed by the main build.
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PHONY += gcc-plugins-check
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gcc-plugins-check: FORCE
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ifdef CONFIG_GCC_PLUGINS
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ifeq ($(PLUGINCC),)
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ifneq ($(GCC_PLUGINS_CFLAGS),)
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# Various gccs between 4.5 and 5.1 have bugs on powerpc due to missing
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# header files. gcc <= 4.6 doesn't work at all, gccs from 4.8 to 5.1 have
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# issues with 64-bit targets.
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ifeq ($(ARCH),powerpc)
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ifeq ($(call cc-ifversion, -le, 0501, y), y)
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@echo "Cannot use CONFIG_GCC_PLUGINS: plugin support on gcc <= 5.1 is buggy on powerpc, please upgrade to gcc 5.2 or newer" >&2 && exit 1
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endif
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endif
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ifeq ($(call cc-ifversion, -ge, 0405, y), y)
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$(Q)$(srctree)/scripts/gcc-plugin.sh --show-error "$(__PLUGINCC)" "$(HOSTCXX)" "$(CC)" || true
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@echo "Cannot use CONFIG_GCC_PLUGINS: your gcc installation does not support plugins, perhaps the necessary headers are missing?" >&2 && exit 1
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else
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@echo "Cannot use CONFIG_GCC_PLUGINS: your gcc version does not support plugins, you should upgrade it to at least gcc 4.5" >&2 && exit 1
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endif
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endif
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endif
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endif
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@:
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# Actually do the build, if requested.
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PHONY += gcc-plugins
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gcc-plugins: scripts_basic gcc-plugins-check
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ifdef CONFIG_GCC_PLUGINS
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$(Q)$(MAKE) $(build)=scripts/gcc-plugins
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endif
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@:
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