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: Emese Revfy <re.emese@xxxxxxxxx> --- Makefile | 8 +- arch/Kconfig | 9 +++ lib/Kconfig.debug | 2 + scripts/Makefile.gcc-plugins | 9 +++ scripts/gcc-plugins/Makefile | 2 + scripts/gcc-plugins/sancov_plugin.c | 143 ++++++++++++++++++++++++++++++++++++ 6 files changed, 170 insertions(+), 3 deletions(-) create mode 100644 scripts/gcc-plugins/sancov_plugin.c diff --git a/Makefile b/Makefile index 3af7b9e..e079cb4 100644 --- a/Makefile +++ b/Makefile @@ -686,10 +686,12 @@ endif KBUILD_CFLAGS += $(stackp-flag) ifdef CONFIG_KCOV - ifeq ($(call cc-option, $(CFLAGS_KCOV)),) - $(warning Cannot use CONFIG_KCOV: \ + ifneq ($(CFLAGS_KCOV),) + ifeq ($(call cc-option, $(CFLAGS_KCOV)),) + $(warning Cannot use CONFIG_KCOV: \ -fsanitize-coverage=trace-pc is not supported by compiler) - CFLAGS_KCOV = + CFLAGS_KCOV = + endif endif endif diff --git a/arch/Kconfig b/arch/Kconfig index e783429..5d856c8 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -380,6 +380,15 @@ config GCC_PLUGIN_CYC_COMPLEXITY N = the number of nodes P = the number of connected components (exit nodes). +config GCC_PLUGIN_SANCOV + bool + depends on GCC_PLUGINS + help + This plugin inserts a __sanitizer_cov_trace_pc() call at the start of + basic blocks. It supports all gcc versions with plugin support (from + gcc-4.5 on). It is based on the commit "Add fuzzing coverage support" + by Dmitry Vyukov <dvyukov@xxxxxxxxxx>. + config HAVE_CC_STACKPROTECTOR bool help diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index f4b797a..507d3fc 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -707,6 +707,8 @@ config KCOV bool "Code coverage for fuzzing" depends on ARCH_HAS_KCOV select DEBUG_FS + select GCC_PLUGINS + select GCC_PLUGIN_SANCOV help KCOV exposes kernel code coverage information in a form suitable for coverage-guided fuzzing (randomized testing). diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index 34ad58b..25a70fb 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -4,6 +4,15 @@ ifdef CONFIG_GCC_PLUGINS gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) += cyc_complexity_plugin.so + ifdef CONFIG_GCC_PLUGIN_SANCOV + ifeq ($(call cc-option, $(CFLAGS_KCOV)),) + gcc-plugin-$(CONFIG_GCC_PLUGIN_SANCOV) += sancov_plugin.so + ifneq ($(PLUGINCC),) + CFLAGS_KCOV = + endif + endif + endif + GCC_PLUGINS_CFLAGS := $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) ifeq ($(PLUGINCC),) diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index 31c72bf..97a923f 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -13,7 +13,9 @@ endif export GCCPLUGINS_DIR HOSTLIBS $(HOSTLIBS)-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) := cyc_complexity_plugin.so +$(HOSTLIBS)-$(CONFIG_GCC_PLUGIN_SANCOV) += sancov_plugin.so always := $($(HOSTLIBS)-y) cyc_complexity_plugin-objs := cyc_complexity_plugin.o +sancov_plugin-objs := sancov_plugin.o diff --git a/scripts/gcc-plugins/sancov_plugin.c b/scripts/gcc-plugins/sancov_plugin.c new file mode 100644 index 0000000..1311744 --- /dev/null +++ b/scripts/gcc-plugins/sancov_plugin.c @@ -0,0 +1,143 @@ +/* + * Copyright 2011-2016 by Emese Revfy <re.emese@xxxxxxxxx> + * Licensed under the GPL v2, or (at your option) v3 + * + * Homepage: + * https://github.com/ephox-gcc-plugins/sancov + * + * 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@xxxxxxxxxx>. + * + * You can read about it more here: + * https://gcc.gnu.org/viewcvs/gcc?limit_changes=0&view=revision&revision=231296 + * http://lwn.net/Articles/674854/ + * https://github.com/google/syzkaller + * https://lwn.net/Articles/677764/ + * + * Usage: + * make run + */ + +#include "gcc-common.h" + +int plugin_is_GPL_compatible; + +tree sancov_fndecl; + +static struct plugin_info sancov_plugin_info = { + .version = "20160402", + .help = "sancov plugin\n", +}; + +static unsigned int sancov_execute(void) +{ + basic_block bb; + + /* Remove this line when this plugin and kcov will be in the kernel. */ + if (!strcmp(DECL_NAME_POINTER(current_function_decl), DECL_NAME_POINTER(sancov_fndecl))) + return 0; + + FOR_EACH_BB_FN(bb, cfun) { + const_gimple stmt; + gcall *gcall; + gimple_stmt_iterator gsi = gsi_after_labels(bb); + + if (gsi_end_p(gsi)) + continue; + + stmt = gsi_stmt(gsi); + gcall = as_a_gcall(gimple_build_call(sancov_fndecl, 0)); + gimple_set_location(gcall, gimple_location(stmt)); + gsi_insert_before(&gsi, gcall, GSI_SAME_STMT); + } + return 0; +} + +#define PASS_NAME sancov + +#define NO_GATE +#define TODO_FLAGS_FINISH TODO_dump_func | TODO_verify_stmts | TODO_update_ssa_no_phi | TODO_verify_flow + +#include "gcc-generate-gimple-pass.h" + +static void sancov_start_unit(void __unused *gcc_data, void __unused *user_data) +{ + tree leaf_attr, nothrow_attr; + tree BT_FN_VOID = build_function_type_list(void_type_node, NULL_TREE); + + sancov_fndecl = build_fn_decl("__sanitizer_cov_trace_pc", BT_FN_VOID); + + DECL_ASSEMBLER_NAME(sancov_fndecl); + TREE_PUBLIC(sancov_fndecl) = 1; + DECL_EXTERNAL(sancov_fndecl) = 1; + DECL_ARTIFICIAL(sancov_fndecl) = 1; + DECL_PRESERVE_P(sancov_fndecl) = 1; + DECL_UNINLINABLE(sancov_fndecl) = 1; + TREE_USED(sancov_fndecl) = 1; + + nothrow_attr = tree_cons(get_identifier("nothrow"), NULL, NULL); + decl_attributes(&sancov_fndecl, nothrow_attr, 0); + gcc_assert(TREE_NOTHROW(sancov_fndecl)); +#if BUILDING_GCC_VERSION > 4005 + leaf_attr = tree_cons(get_identifier("leaf"), NULL, NULL); + decl_attributes(&sancov_fndecl, leaf_attr, 0); +#endif +} + +int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) +{ + int i; + struct register_pass_info sancov_plugin_pass_info; + const char * const plugin_name = plugin_info->base_name; + const int argc = plugin_info->argc; + const struct plugin_argument * const argv = plugin_info->argv; + bool enable = true; + + static const struct ggc_root_tab gt_ggc_r_gt_sancov[] = { + { + .base = &sancov_fndecl, + .nelt = 1, + .stride = sizeof(sancov_fndecl), + .cb = >_ggc_mx_tree_node, + .pchw = >_pch_nx_tree_node + }, + LAST_GGC_ROOT_TAB + }; + + /* BBs can be split afterwards?? */ + sancov_plugin_pass_info.pass = make_sancov_pass(); +#if BUILDING_GCC_VERSION >= 4009 + sancov_plugin_pass_info.reference_pass_name = "asan"; +#else + sancov_plugin_pass_info.reference_pass_name = "nrv"; +#endif + sancov_plugin_pass_info.ref_pass_instance_number = 0; + sancov_plugin_pass_info.pos_op = PASS_POS_INSERT_BEFORE; + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + for (i = 0; i < argc; ++i) { + if (!strcmp(argv[i].key, "no-sancov")) { + enable = false; + continue; + } + error(G_("unkown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key); + } + + register_callback(plugin_name, PLUGIN_INFO, NULL, &sancov_plugin_info); + + if (!enable) + return 0; + +#if BUILDING_GCC_VERSION < 6000 + register_callback(plugin_name, PLUGIN_START_UNIT, &sancov_start_unit, NULL); + register_callback(plugin_name, PLUGIN_REGISTER_GGC_ROOTS, NULL, (void *)>_ggc_r_gt_sancov); + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &sancov_plugin_pass_info); +#endif + + return 0; +} -- 2.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
