From 6b90bd4ba40b38dc13c2782469c1c77e4ed79915 Mon Sep 17 00:00:00 2001 From: Emese Revfy Date: Tue, 24 May 2016 00:09:38 +0200 Subject: GCC plugin infrastructure This patch allows to build the whole kernel with GCC plugins. It was ported from grsecurity/PaX. The infrastructure supports building out-of-tree modules and building in a separate directory. Cross-compilation is supported too. Currently the x86, arm, arm64 and uml architectures enable plugins. The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory there. The plugins compile with these options: * -fno-rtti: gcc is compiled with this option so the plugins must use it too * -fno-exceptions: this is inherited from gcc too * -fasynchronous-unwind-tables: this is inherited from gcc too * -ggdb: it is useful for debugging a plugin (better backtrace on internal errors) * -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h) * -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version variable, plugin-version.h) The infrastructure introduces a new Makefile target called gcc-plugins. It supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++). This script also checks the availability of the included headers in scripts/gcc-plugins/gcc-common.h. The gcc-common.h header contains frequently included headers for GCC plugins and it has a compatibility layer for the supported gcc versions. The gcc-generate-*-pass.h headers automatically generate the registration structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes. Note that 'make clean' keeps the *.so files (only the distclean or mrproper targets clean all) because they are needed for out-of-tree modules. Based on work created by the PaX Team. Signed-off-by: Emese Revfy Acked-by: Kees Cook Signed-off-by: Michal Marek --- arch/Kconfig | 15 +++++++++++++++ arch/arm/Kconfig | 1 + arch/arm64/Kconfig | 1 + arch/um/Kconfig.common | 1 + arch/x86/Kconfig | 1 + arch/x86/entry/vdso/Makefile | 3 ++- 6 files changed, 21 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/Kconfig b/arch/Kconfig index d794384a0404..1b93632198fa 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -357,6 +357,21 @@ config SECCOMP_FILTER See Documentation/prctl/seccomp_filter.txt for details. +config HAVE_GCC_PLUGINS + bool + help + An arch should select this symbol if it supports building with + GCC plugins. + +menuconfig GCC_PLUGINS + bool "GCC plugins" + depends on HAVE_GCC_PLUGINS + help + GCC plugins are loadable modules that provide extra features to the + compiler. They are useful for runtime instrumentation and static analysis. + + See Documentation/gcc-plugins.txt for details. + config HAVE_CC_STACKPROTECTOR bool help diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 90542db1220d..ce590468ffa2 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -54,6 +54,7 @@ config ARM select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL) select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL) select HAVE_FUNCTION_TRACER if (!XIP_KERNEL) + select HAVE_GCC_PLUGINS select HAVE_GENERIC_DMA_COHERENT select HAVE_HW_BREAKPOINT if (PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)) select HAVE_IDE if PCI || ISA || PCMCIA diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 76747d92bc72..24e7bd6778ea 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -76,6 +76,7 @@ config ARM64 select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_TRACER select HAVE_FUNCTION_GRAPH_TRACER + select HAVE_GCC_PLUGINS select HAVE_GENERIC_DMA_COHERENT select HAVE_HW_BREAKPOINT if PERF_EVENTS select HAVE_IRQ_TIME_ACCOUNTING diff --git a/arch/um/Kconfig.common b/arch/um/Kconfig.common index cc0013475444..58650d098fb4 100644 --- a/arch/um/Kconfig.common +++ b/arch/um/Kconfig.common @@ -9,6 +9,7 @@ config UML select GENERIC_CPU_DEVICES select GENERIC_IO select GENERIC_CLOCKEVENTS + select HAVE_GCC_PLUGINS select TTY # Needed for line.c config MMU diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 0a7b885964ba..65e7701bd429 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -111,6 +111,7 @@ config X86 select HAVE_FUNCTION_GRAPH_FP_TEST select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER + select HAVE_GCC_PLUGINS select HAVE_GENERIC_DMA_COHERENT if X86_32 select HAVE_HW_BREAKPOINT select HAVE_IDE diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index 253b72eaade6..f9123163a850 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -75,7 +75,7 @@ CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \ -fno-omit-frame-pointer -foptimize-sibling-calls \ -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO -$(vobjs): KBUILD_CFLAGS += $(CFL) +$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) $(CFL) # # vDSO code runs in userspace and -pg doesn't help with profiling anyway. @@ -145,6 +145,7 @@ 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 $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32)) KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls) -- cgit v1.2.3-59-g8ed1b From 0dae776c6bf31e779c172753f6e2d6426eb42523 Mon Sep 17 00:00:00 2001 From: Emese Revfy Date: Tue, 24 May 2016 00:10:35 +0200 Subject: Add Cyclomatic complexity GCC plugin Add a very simple plugin to demonstrate the GCC plugin infrastructure. This GCC plugin computes the cyclomatic complexity of each function. The complexity M of a function's control flow graph is defined as: M = E - N + 2P where E = the number of edges N = the number of nodes P = the number of connected components (exit nodes). Signed-off-by: Emese Revfy Acked-by: Kees Cook Signed-off-by: Michal Marek --- arch/Kconfig | 12 +++++ scripts/Makefile.gcc-plugins | 1 + scripts/gcc-plugins/Makefile | 1 + scripts/gcc-plugins/cyc_complexity_plugin.c | 73 +++++++++++++++++++++++++++++ 4 files changed, 87 insertions(+) create mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c (limited to 'arch') diff --git a/arch/Kconfig b/arch/Kconfig index 1b93632198fa..04ca45262ad1 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -372,6 +372,18 @@ menuconfig GCC_PLUGINS See Documentation/gcc-plugins.txt for details. +config GCC_PLUGIN_CYC_COMPLEXITY + bool "Compute the cyclomatic complexity of a function" + depends on GCC_PLUGINS + help + The complexity M of a function's control flow graph is defined as: + M = E - N + 2P + where + + E = the number of edges + N = the number of nodes + P = the number of connected components (exit nodes). + config HAVE_CC_STACKPROTECTOR bool help diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index bcc373dcb3b5..b4a189c95a8a 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -2,6 +2,7 @@ ifdef CONFIG_GCC_PLUGINS __PLUGINCC := $(call cc-ifversion, -ge, 0408, $(HOSTCXX), $(HOSTCC)) PLUGINCC := $(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-plugin.sh "$(__PLUGINCC)" "$(HOSTCXX)" "$(CC)") + gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) += cyc_complexity_plugin.so GCC_PLUGINS_CFLAGS := $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index a4c93419d5d1..c60ba4bef57c 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -17,4 +17,5 @@ export GCCPLUGINS_DIR HOSTLIBS $(HOSTLIBS)-y := $(GCC_PLUGIN) always := $($(HOSTLIBS)-y) +cyc_complexity_plugin-objs := cyc_complexity_plugin.o clean-files += *.so diff --git a/scripts/gcc-plugins/cyc_complexity_plugin.c b/scripts/gcc-plugins/cyc_complexity_plugin.c new file mode 100644 index 000000000000..34df974c6ba3 --- /dev/null +++ b/scripts/gcc-plugins/cyc_complexity_plugin.c @@ -0,0 +1,73 @@ +/* + * Copyright 2011-2016 by Emese Revfy + * Licensed under the GPL v2, or (at your option) v3 + * + * Homepage: + * https://github.com/ephox-gcc-plugins/cyclomatic_complexity + * + * http://en.wikipedia.org/wiki/Cyclomatic_complexity + * The complexity M is then defined as: + * M = E - N + 2P + * where + * + * E = the number of edges of the graph + * N = the number of nodes of the graph + * P = the number of connected components (exit nodes). + * + * Usage (4.5 - 5): + * $ make clean; make run + */ + +#include "gcc-common.h" + +int plugin_is_GPL_compatible; + +static struct plugin_info cyc_complexity_plugin_info = { + .version = "20160225", + .help = "Cyclomatic Complexity\n", +}; + +static unsigned int cyc_complexity_execute(void) +{ + int complexity; + expanded_location xloc; + + /* M = E - N + 2P */ + complexity = n_edges_for_fn(cfun) - n_basic_blocks_for_fn(cfun) + 2; + + xloc = expand_location(DECL_SOURCE_LOCATION(current_function_decl)); + fprintf(stderr, "Cyclomatic Complexity %d %s:%s\n", complexity, + xloc.file, DECL_NAME_POINTER(current_function_decl)); + + return 0; +} + +#define PASS_NAME cyc_complexity + +#define NO_GATE +#define TODO_FLAGS_FINISH TODO_dump_func + +#include "gcc-generate-gimple-pass.h" + +int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version) +{ + const char * const plugin_name = plugin_info->base_name; + struct register_pass_info cyc_complexity_pass_info; + + cyc_complexity_pass_info.pass = make_cyc_complexity_pass(); + cyc_complexity_pass_info.reference_pass_name = "ssa"; + cyc_complexity_pass_info.ref_pass_instance_number = 1; + cyc_complexity_pass_info.pos_op = PASS_POS_INSERT_AFTER; + + if (!plugin_default_version_check(version, &gcc_version)) { + error(G_("incompatible gcc/plugin versions")); + return 1; + } + + register_callback(plugin_name, PLUGIN_INFO, NULL, + &cyc_complexity_plugin_info); + register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, + &cyc_complexity_pass_info); + + return 0; +} -- cgit v1.2.3-59-g8ed1b From 543c37cb165049c3be24a0d4733e67caa2b33eef Mon Sep 17 00:00:00 2001 From: Emese Revfy Date: Tue, 24 May 2016 00:11:37 +0200 Subject: 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: Emese Revfy Acked-by: Kees Cook Signed-off-by: Michal Marek --- Makefile | 10 +-- arch/Kconfig | 9 +++ arch/x86/purgatory/Makefile | 2 + lib/Kconfig.debug | 2 + scripts/Makefile.gcc-plugins | 21 +++++- scripts/gcc-plugins/Makefile | 6 ++ scripts/gcc-plugins/sancov_plugin.c | 144 ++++++++++++++++++++++++++++++++++++ 7 files changed, 184 insertions(+), 10 deletions(-) create mode 100644 scripts/gcc-plugins/sancov_plugin.c (limited to 'arch') diff --git a/Makefile b/Makefile index 20fcf4b26fbc..c3d494ba3ae1 100644 --- a/Makefile +++ b/Makefile @@ -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,) diff --git a/arch/Kconfig b/arch/Kconfig index 04ca45262ad1..05f1e95b796d 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -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 . + config HAVE_CC_STACKPROTECTOR bool help diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 12734a96df47..ac58c1616408 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -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. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 77d7d034bac3..b7827dca3fec 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -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). diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins index b4a189c95a8a..5e22b60589c1 100644 --- a/scripts/Makefile.gcc-plugins +++ b/scripts/Makefile.gcc-plugins @@ -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 += $(GCC_PLUGINS_CFLAGS) diff --git a/scripts/gcc-plugins/Makefile b/scripts/gcc-plugins/Makefile index c60ba4bef57c..88c8ec47232b 100644 --- a/scripts/gcc-plugins/Makefile +++ b/scripts/gcc-plugins/Makefile @@ -14,8 +14,14 @@ endif export GCCPLUGINS_DIR HOSTLIBS +ifneq ($(CFLAGS_KCOV), $(SANCOV_PLUGIN)) + GCC_PLUGIN := $(filter-out $(SANCOV_PLUGIN), $(GCC_PLUGIN)) +endif + $(HOSTLIBS)-y := $(GCC_PLUGIN) always := $($(HOSTLIBS)-y) cyc_complexity_plugin-objs := cyc_complexity_plugin.o +sancov_plugin-objs := sancov_plugin.o + clean-files += *.so diff --git a/scripts/gcc-plugins/sancov_plugin.c b/scripts/gcc-plugins/sancov_plugin.c new file mode 100644 index 000000000000..aedd6113cb73 --- /dev/null +++ b/scripts/gcc-plugins/sancov_plugin.c @@ -0,0 +1,144 @@ +/* + * Copyright 2011-2016 by Emese Revfy + * 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 . + * + * 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; +} -- cgit v1.2.3-59-g8ed1b From 58ab5e0c2c40ec48e682179e8f2e4cda2ece201b Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Wed, 15 Jun 2016 17:45:46 +0200 Subject: Kbuild: arch: look for generated headers in obtree There are very few files that need add an -I$(obj) gcc for the preprocessor or the assembler. For C files, we add always these for both the objtree and srctree, but for the other ones we require the Makefile to add them, and Kbuild then adds it for both trees. As a preparation for changing the meaning of the -I$(obj) directive to only refer to the srctree, this changes the two instances in arch/x86 to use an explictit $(objtree) prefix where needed, otherwise we won't find the headers any more, as reported by the kbuild 0day builder. arch/x86/realmode/rm/realmode.lds.S:75:20: fatal error: pasyms.h: No such file or directory Signed-off-by: Arnd Bergmann Signed-off-by: Michal Marek --- arch/alpha/boot/Makefile | 2 +- arch/powerpc/boot/Makefile | 2 +- arch/powerpc/kvm/Makefile | 2 +- arch/s390/boot/compressed/Makefile | 4 ++-- arch/um/Makefile | 4 ++-- arch/x86/boot/Makefile | 2 +- arch/x86/realmode/rm/Makefile | 2 +- 7 files changed, 9 insertions(+), 9 deletions(-) (limited to 'arch') diff --git a/arch/alpha/boot/Makefile b/arch/alpha/boot/Makefile index 8399bd0e68e8..0cbe4c59d3ce 100644 --- a/arch/alpha/boot/Makefile +++ b/arch/alpha/boot/Makefile @@ -15,7 +15,7 @@ targets := vmlinux.gz vmlinux \ OBJSTRIP := $(obj)/tools/objstrip HOSTCFLAGS := -Wall -I$(objtree)/usr/include -BOOTCFLAGS += -I$(obj) -I$(srctree)/$(obj) +BOOTCFLAGS += -I$(objtree)/$(obj) -I$(srctree)/$(obj) # SRM bootable image. Copy to offset 512 of a partition. $(obj)/bootimage: $(addprefix $(obj)/tools/,mkbb lxboot bootlx) $(obj)/vmlinux.nh diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile index 8fe78a3efc92..ad3782610cf1 100644 --- a/arch/powerpc/boot/Makefile +++ b/arch/powerpc/boot/Makefile @@ -43,7 +43,7 @@ ifeq ($(call cc-option-yn, -fstack-protector),y) BOOTCFLAGS += -fno-stack-protector endif -BOOTCFLAGS += -I$(obj) -I$(srctree)/$(obj) +BOOTCFLAGS += -I$(objtree)/$(obj) -I$(srctree)/$(obj) DTC_FLAGS ?= -p 1024 diff --git a/arch/powerpc/kvm/Makefile b/arch/powerpc/kvm/Makefile index eba0bea6e032..1f9e5529e692 100644 --- a/arch/powerpc/kvm/Makefile +++ b/arch/powerpc/kvm/Makefile @@ -20,7 +20,7 @@ common-objs-y += powerpc.o emulate.o emulate_loadstore.o obj-$(CONFIG_KVM_EXIT_TIMING) += timing.o obj-$(CONFIG_KVM_BOOK3S_HANDLER) += book3s_exports.o -AFLAGS_booke_interrupts.o := -I$(obj) +AFLAGS_booke_interrupts.o := -I$(objtree)/$(obj) kvm-e500-objs := \ $(common-objs-y) \ diff --git a/arch/s390/boot/compressed/Makefile b/arch/s390/boot/compressed/Makefile index 1dd210347e12..2657a29a2026 100644 --- a/arch/s390/boot/compressed/Makefile +++ b/arch/s390/boot/compressed/Makefile @@ -31,10 +31,10 @@ quiet_cmd_sizes = GEN $@ $(obj)/sizes.h: vmlinux $(call if_changed,sizes) -AFLAGS_head.o += -I$(obj) +AFLAGS_head.o += -I$(objtree)/$(obj) $(obj)/head.o: $(obj)/sizes.h -CFLAGS_misc.o += -I$(obj) +CFLAGS_misc.o += -I$(objtree)/$(obj) $(obj)/misc.o: $(obj)/sizes.h OBJCOPYFLAGS_vmlinux.bin := -R .comment -S diff --git a/arch/um/Makefile b/arch/um/Makefile index e3abe6f3156d..0ca46ededfc7 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -78,8 +78,8 @@ include $(ARCH_DIR)/Makefile-os-$(OS) KBUILD_CPPFLAGS += -I$(srctree)/$(HOST_DIR)/include \ -I$(srctree)/$(HOST_DIR)/include/uapi \ - -I$(HOST_DIR)/include/generated \ - -I$(HOST_DIR)/include/generated/uapi + -I$(objtree)/$(HOST_DIR)/include/generated \ + -I$(objtree)/$(HOST_DIR)/include/generated/uapi # -Derrno=kernel_errno - This turns all kernel references to errno into # kernel_errno to separate them from the libc errno. This allows -fno-common diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index 700a9c6e6159..f3784c35fda2 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -96,7 +96,7 @@ $(obj)/zoffset.h: $(obj)/compressed/vmlinux FORCE $(call if_changed,zoffset) -AFLAGS_header.o += -I$(obj) +AFLAGS_header.o += -I$(objtree)/$(obj) $(obj)/header.o: $(obj)/zoffset.h LDFLAGS_setup.elf := -T diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index c556c5ae8de5..25012abc3409 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -48,7 +48,7 @@ targets += realmode.lds $(obj)/realmode.lds: $(obj)/pasyms.h LDFLAGS_realmode.elf := --emit-relocs -T -CPPFLAGS_realmode.lds += -P -C -I$(obj) +CPPFLAGS_realmode.lds += -P -C -I$(objtree)/$(obj) targets += realmode.elf $(obj)/realmode.elf: $(obj)/realmode.lds $(REALMODE_OBJS) FORCE -- cgit v1.2.3-59-g8ed1b From 228d96c603cf53e32f672c0e459d2adbc5a4609a Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 26 Jul 2016 14:26:20 -0700 Subject: kbuild: Abort build on bad stack protector flag Before, the stack protector flag was sanity checked before .config had been reprocessed. This meant the build couldn't be aborted early, and only a warning could be emitted followed later by the compiler blowing up with an unknown flag. This has caused a lot of confusion over time, so this splits the flag selection from sanity checking and performs the sanity checking after the make has been restarted from a reprocessed .config, so builds can be aborted as early as possible now. Additionally moves the x86-specific sanity check to the same location, since it suffered from the same warn-then-wait-for-compiler-failure problem. Signed-off-by: Kees Cook Signed-off-by: Michal Marek --- Makefile | 67 +++++++++++++++++++++++++++++++++---------------------- arch/x86/Makefile | 8 ------- 2 files changed, 40 insertions(+), 35 deletions(-) (limited to 'arch') diff --git a/Makefile b/Makefile index 7aa6f8c4cc53..08aac0a7c85f 100644 --- a/Makefile +++ b/Makefile @@ -655,41 +655,26 @@ ifneq ($(CONFIG_FRAME_WARN),0) KBUILD_CFLAGS += $(call cc-option,-Wframe-larger-than=${CONFIG_FRAME_WARN}) endif -# Handle stack protector mode. -# -# Since kbuild can potentially perform two passes (first with the old -# .config values and then with updated .config values), we cannot error out -# if a desired compiler option is unsupported. If we were to error, kbuild -# could never get to the second pass and actually notice that we changed -# the option to something that was supported. -# -# Additionally, we don't want to fallback and/or silently change which compiler -# flags will be used, since that leads to producing kernels with different -# security feature characteristics depending on the compiler used. ("But I -# selected CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!") -# -# The middle ground is to warn here so that the failed option is obvious, but -# to let the build fail with bad compiler flags so that we can't produce a -# kernel when there is a CONFIG and compiler mismatch. -# +# This selects the stack protector compiler flag. Testing it is delayed +# until after .config has been reprocessed, in the prepare-compiler-check +# target. ifdef CONFIG_CC_STACKPROTECTOR_REGULAR stackp-flag := -fstack-protector - ifeq ($(call cc-option, $(stackp-flag)),) - $(warning Cannot use CONFIG_CC_STACKPROTECTOR_REGULAR: \ - -fstack-protector not supported by compiler) - endif + stackp-name := REGULAR else ifdef CONFIG_CC_STACKPROTECTOR_STRONG stackp-flag := -fstack-protector-strong - ifeq ($(call cc-option, $(stackp-flag)),) - $(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \ - -fstack-protector-strong not supported by compiler) - endif + stackp-name := STRONG else # Force off for distro compilers that enable stack protector by default. stackp-flag := $(call cc-option, -fno-stack-protector) endif endif +# Find arch-specific stack protector compiler sanity-checking script. +ifdef CONFIG_CC_STACKPROTECTOR + stackp-path := $(srctree)/scripts/gcc-$(SRCARCH)_$(BITS)-has-stack-protector.sh + stackp-check := $(wildcard $(stackp-path)) +endif KBUILD_CFLAGS += $(stackp-flag) ifeq ($(cc-name),clang) @@ -1017,8 +1002,10 @@ ifneq ($(KBUILD_SRC),) fi; endif -# prepare2 creates a makefile if using a separate output directory -prepare2: prepare3 outputmakefile asm-generic +# prepare2 creates a makefile if using a separate output directory. +# From this point forward, .config has been reprocessed, so any rules +# that need to depend on updated CONFIG_* values can be checked here. +prepare2: prepare3 prepare-compiler-check outputmakefile asm-generic prepare1: prepare2 $(version_h) include/generated/utsrelease.h \ include/config/auto.conf @@ -1049,6 +1036,32 @@ endif PHONY += prepare-objtool prepare-objtool: $(objtool_target) +# Check for CONFIG flags that require compiler support. Abort the build +# after .config has been processed, but before the kernel build starts. +# +# For security-sensitive CONFIG options, we don't want to fallback and/or +# silently change which compiler flags will be used, since that leads to +# producing kernels with different security feature characteristics +# depending on the compiler used. (For example, "But I selected +# CC_STACKPROTECTOR_STRONG! Why did it build with _REGULAR?!") +PHONY += prepare-compiler-check +prepare-compiler-check: FORCE +# Make sure compiler supports requested stack protector flag. +ifdef stackp-name + ifeq ($(call cc-option, $(stackp-flag)),) + @echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \ + $(stackp-flag) not supported by compiler >&2 && exit 1 + endif +endif +# Make sure compiler does not have buggy stack-protector support. +ifdef stackp-check + ifneq ($(shell $(CONFIG_SHELL) $(stackp-check) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y) + @echo Cannot use CONFIG_CC_STACKPROTECTOR_$(stackp-name): \ + $(stackp-flag) available but compiler is broken >&2 && exit 1 + endif +endif + @: + # Generate some files # --------------------------------------------------------------------------- diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 6fce7f096b88..830ed391e7ef 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -126,14 +126,6 @@ else KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args) endif -# Make sure compiler does not have buggy stack-protector support. -ifdef CONFIG_CC_STACKPROTECTOR - cc_has_sp := $(srctree)/scripts/gcc-x86_$(BITS)-has-stack-protector.sh - ifneq ($(shell $(CONFIG_SHELL) $(cc_has_sp) $(CC) $(KBUILD_CPPFLAGS) $(biarch)),y) - $(warning stack-protector enabled but compiler support broken) - endif -endif - ifdef CONFIG_X86_X32 x32_ld_ok := $(call try-run,\ /bin/echo -e '1: .quad 1b' | \ -- cgit v1.2.3-59-g8ed1b From a519167e753e6a89476115375b65a7eb6ec485b3 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sat, 11 Jun 2016 09:09:28 -0700 Subject: gcc-plugins: disable under COMPILE_TEST Since adding the gcc plugin development headers is required for the gcc plugin support, we should ease into this new kernel build dependency more slowly. For now, disable the gcc plugins under COMPILE_TEST so that all*config builds will skip it. Signed-off-by: Kees Cook Signed-off-by: Michal Marek --- arch/Kconfig | 1 + lib/Kconfig.debug | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/Kconfig b/arch/Kconfig index 05f1e95b796d..cae4bc587eae 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -366,6 +366,7 @@ config HAVE_GCC_PLUGINS menuconfig GCC_PLUGINS bool "GCC plugins" depends on HAVE_GCC_PLUGINS + depends on !COMPILE_TEST help GCC plugins are loadable modules that provide extra features to the compiler. They are useful for runtime instrumentation and static analysis. diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index b7827dca3fec..7936e5e4da9d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -708,8 +708,8 @@ config KCOV bool "Code coverage for fuzzing" depends on ARCH_HAS_KCOV select DEBUG_FS - select GCC_PLUGINS - select GCC_PLUGIN_SANCOV + select GCC_PLUGINS if !COMPILE_TEST + select GCC_PLUGIN_SANCOV if !COMPILE_TEST help KCOV exposes kernel code coverage information in a form suitable for coverage-guided fuzzing (randomized testing). -- cgit v1.2.3-59-g8ed1b