Merge tag 'gcc-plugins-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc-plugins updates from Kees Cook:
"This includes infrastructure updates and the structleak plugin, which
performs forced initialization of certain structures to avoid possible
information exposures to userspace.
Summary:
- infrastructure updates (gcc-common.h)
- introduce structleak plugin for forced initialization of some
structures"
* tag 'gcc-plugins-v4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Add structleak for more stack initialization
gcc-plugins: consolidate on PASS_INFO macro
gcc-plugins: add PASS_INFO and build_const_char_string()
diff --git a/arch/Kconfig b/arch/Kconfig
index 33f5a55..2bbf5ba 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -410,6 +410,28 @@
* https://grsecurity.net/
* https://pax.grsecurity.net/
+config GCC_PLUGIN_STRUCTLEAK
+ bool "Force initialization of variables containing userspace addresses"
+ depends on GCC_PLUGINS
+ help
+ This plugin zero-initializes any structures that containing a
+ __user attribute. This can prevent some classes of information
+ exposures.
+
+ This plugin was ported from grsecurity/PaX. More information at:
+ * https://grsecurity.net/
+ * https://pax.grsecurity.net/
+
+config GCC_PLUGIN_STRUCTLEAK_VERBOSE
+ bool "Report forcefully initialized variables"
+ depends on GCC_PLUGIN_STRUCTLEAK
+ depends on !COMPILE_TEST
+ help
+ This option will cause a warning to be printed each time the
+ structleak plugin finds a variable it thinks needs to be
+ initialized. Since not all existing initializers are detected
+ by the plugin, this can produce false positive warnings.
+
config HAVE_CC_STACKPROTECTOR
bool
help
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index cf0fa5d..91c30cb 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -27,7 +27,11 @@ extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
# define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(p)->member))
#else /* __CHECKER__ */
-# define __user
+# ifdef STRUCTLEAK_PLUGIN
+# define __user __attribute__((user))
+# else
+# define __user
+# endif
# define __kernel
# define __safe
# define __force
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 060d2cb..a084f7a 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -25,6 +25,10 @@
endif
endif
+ gcc-plugin-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += structleak_plugin.so
+ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE) += -fplugin-arg-structleak_plugin-verbose
+ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += -DSTRUCTLEAK_PLUGIN
+
GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y))
export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR
diff --git a/scripts/gcc-plugins/cyc_complexity_plugin.c b/scripts/gcc-plugins/cyc_complexity_plugin.c
index 8af7db0..1909ec6 100644
--- a/scripts/gcc-plugins/cyc_complexity_plugin.c
+++ b/scripts/gcc-plugins/cyc_complexity_plugin.c
@@ -52,12 +52,8 @@ static unsigned int cyc_complexity_execute(void)
__visible 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;
+ PASS_INFO(cyc_complexity, "ssa", 1, PASS_POS_INSERT_AFTER);
if (!plugin_default_version_check(version, &gcc_version)) {
error(G_("incompatible gcc/plugin versions"));
diff --git a/scripts/gcc-plugins/gcc-common.h b/scripts/gcc-plugins/gcc-common.h
index 12262c0..b232ab1 100644
--- a/scripts/gcc-plugins/gcc-common.h
+++ b/scripts/gcc-plugins/gcc-common.h
@@ -26,6 +26,9 @@
#include "except.h"
#include "function.h"
#include "toplev.h"
+#if BUILDING_GCC_VERSION >= 5000
+#include "expr.h"
+#endif
#include "basic-block.h"
#include "intl.h"
#include "ggc.h"
@@ -80,6 +83,9 @@
#include "diagnostic.h"
#include "tree-dump.h"
#include "tree-pass.h"
+#if BUILDING_GCC_VERSION >= 4009
+#include "pass_manager.h"
+#endif
#include "predict.h"
#include "ipa-utils.h"
@@ -119,20 +125,17 @@
#include "builtins.h"
#endif
-/* #include "expr.h" where are you... */
-extern rtx emit_move_insn(rtx x, rtx y);
-
/* missing from basic_block.h... */
-extern void debug_dominance_info(enum cdi_direction dir);
-extern void debug_dominance_tree(enum cdi_direction dir, basic_block root);
+void debug_dominance_info(enum cdi_direction dir);
+void debug_dominance_tree(enum cdi_direction dir, basic_block root);
#if BUILDING_GCC_VERSION == 4006
-extern void debug_gimple_stmt(gimple);
-extern void debug_gimple_seq(gimple_seq);
-extern void print_gimple_seq(FILE *, gimple_seq, int, int);
-extern void print_gimple_stmt(FILE *, gimple, int, int);
-extern void print_gimple_expr(FILE *, gimple, int, int);
-extern void dump_gimple_stmt(pretty_printer *, gimple, int, int);
+void debug_gimple_stmt(gimple);
+void debug_gimple_seq(gimple_seq);
+void print_gimple_seq(FILE *, gimple_seq, int, int);
+void print_gimple_stmt(FILE *, gimple, int, int);
+void print_gimple_expr(FILE *, gimple, int, int);
+void dump_gimple_stmt(pretty_printer *, gimple, int, int);
#endif
#define __unused __attribute__((__unused__))
@@ -146,6 +149,29 @@ extern void dump_gimple_stmt(pretty_printer *, gimple, int, int);
/* should come from c-tree.h if only it were installed for gcc 4.5... */
#define C_TYPE_FIELDS_READONLY(TYPE) TREE_LANG_FLAG_1(TYPE)
+static inline tree build_const_char_string(int len, const char *str)
+{
+ tree cstr, elem, index, type;
+
+ cstr = build_string(len, str);
+ elem = build_type_variant(char_type_node, 1, 0);
+ index = build_index_type(size_int(len - 1));
+ type = build_array_type(elem, index);
+ TREE_TYPE(cstr) = type;
+ TREE_CONSTANT(cstr) = 1;
+ TREE_READONLY(cstr) = 1;
+ TREE_STATIC(cstr) = 1;
+ return cstr;
+}
+
+#define PASS_INFO(NAME, REF, ID, POS) \
+struct register_pass_info NAME##_pass_info = { \
+ .pass = make_##NAME##_pass(), \
+ .reference_pass_name = REF, \
+ .ref_pass_instance_number = ID, \
+ .pos_op = POS, \
+}
+
#if BUILDING_GCC_VERSION == 4005
#define FOR_EACH_LOCAL_DECL(FUN, I, D) \
for (tree vars = (FUN)->local_decls, (I) = 0; \
@@ -527,6 +553,8 @@ static inline const greturn *as_a_const_greturn(const_gimple stmt)
#define section_name_prefix LTO_SECTION_NAME_PREFIX
#define fatal_error(loc, gmsgid, ...) fatal_error((gmsgid), __VA_ARGS__)
+rtx emit_move_insn(rtx x, rtx y);
+
typedef struct rtx_def rtx_insn;
static inline const char *get_decl_section_name(const_tree decl)
@@ -643,6 +671,11 @@ static inline const greturn *as_a_const_greturn(const_gimple stmt)
#define NODE_DECL(node) (node)->decl
#define cgraph_node_name(node) (node)->name()
#define NODE_IMPLICIT_ALIAS(node) (node)->cpp_implicit_alias
+
+static inline opt_pass *get_pass_for_id(int id)
+{
+ return g->get_passes()->get_pass_for_id(id);
+}
#endif
#if BUILDING_GCC_VERSION >= 5000 && BUILDING_GCC_VERSION < 6000
diff --git a/scripts/gcc-plugins/latent_entropy_plugin.c b/scripts/gcc-plugins/latent_entropy_plugin.c
index 8ff203a..6526496 100644
--- a/scripts/gcc-plugins/latent_entropy_plugin.c
+++ b/scripts/gcc-plugins/latent_entropy_plugin.c
@@ -592,12 +592,6 @@ __visible int plugin_init(struct plugin_name_args *plugin_info,
const struct plugin_argument * const argv = plugin_info->argv;
int i;
- struct register_pass_info latent_entropy_pass_info;
-
- latent_entropy_pass_info.pass = make_latent_entropy_pass();
- latent_entropy_pass_info.reference_pass_name = "optimized";
- latent_entropy_pass_info.ref_pass_instance_number = 1;
- latent_entropy_pass_info.pos_op = PASS_POS_INSERT_BEFORE;
static const struct ggc_root_tab gt_ggc_r_gt_latent_entropy[] = {
{
.base = &latent_entropy_decl,
@@ -609,6 +603,8 @@ __visible int plugin_init(struct plugin_name_args *plugin_info,
LAST_GGC_ROOT_TAB
};
+ PASS_INFO(latent_entropy, "optimized", 1, PASS_POS_INSERT_BEFORE);
+
if (!plugin_default_version_check(version, &gcc_version)) {
error(G_("incompatible gcc/plugin versions"));
return 1;
diff --git a/scripts/gcc-plugins/sancov_plugin.c b/scripts/gcc-plugins/sancov_plugin.c
index 70f5fe0..9b0b5cb 100644
--- a/scripts/gcc-plugins/sancov_plugin.c
+++ b/scripts/gcc-plugins/sancov_plugin.c
@@ -89,7 +89,6 @@ static void sancov_start_unit(void __unused *gcc_data, void __unused *user_data)
__visible 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;
@@ -107,14 +106,11 @@ __visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gc
};
/* 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";
+ PASS_INFO(sancov, "asan", 0, PASS_POS_INSERT_BEFORE);
#else
- sancov_plugin_pass_info.reference_pass_name = "nrv";
+ PASS_INFO(sancov, "nrv", 1, PASS_POS_INSERT_BEFORE);
#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"));
diff --git a/scripts/gcc-plugins/structleak_plugin.c b/scripts/gcc-plugins/structleak_plugin.c
new file mode 100644
index 0000000..fa3d7a4
--- /dev/null
+++ b/scripts/gcc-plugins/structleak_plugin.c
@@ -0,0 +1,246 @@
+/*
+ * Copyright 2013-2017 by PaX Team <pageexec@freemail.hu>
+ * Licensed under the GPL v2
+ *
+ * Note: the choice of the license means that the compilation process is
+ * NOT 'eligible' as defined by gcc's library exception to the GPL v3,
+ * but for the kernel it doesn't matter since it doesn't link against
+ * any of the gcc libraries
+ *
+ * gcc plugin to forcibly initialize certain local variables that could
+ * otherwise leak kernel stack to userland if they aren't properly initialized
+ * by later code
+ *
+ * Homepage: http://pax.grsecurity.net/
+ *
+ * Options:
+ * -fplugin-arg-structleak_plugin-disable
+ * -fplugin-arg-structleak_plugin-verbose
+ *
+ * Usage:
+ * $ # for 4.5/4.6/C based 4.7
+ * $ gcc -I`gcc -print-file-name=plugin`/include -I`gcc -print-file-name=plugin`/include/c-family -fPIC -shared -O2 -o structleak_plugin.so structleak_plugin.c
+ * $ # for C++ based 4.7/4.8+
+ * $ g++ -I`g++ -print-file-name=plugin`/include -I`g++ -print-file-name=plugin`/include/c-family -fPIC -shared -O2 -o structleak_plugin.so structleak_plugin.c
+ * $ gcc -fplugin=./structleak_plugin.so test.c -O2
+ *
+ * TODO: eliminate redundant initializers
+ * increase type coverage
+ */
+
+#include "gcc-common.h"
+
+/* unused C type flag in all versions 4.5-6 */
+#define TYPE_USERSPACE(TYPE) TYPE_LANG_FLAG_5(TYPE)
+
+__visible int plugin_is_GPL_compatible;
+
+static struct plugin_info structleak_plugin_info = {
+ .version = "201607271510vanilla",
+ .help = "disable\tdo not activate plugin\n"
+ "verbose\tprint all initialized variables\n",
+};
+
+static bool verbose;
+
+static tree handle_user_attribute(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
+{
+ *no_add_attrs = true;
+
+ /* check for types? for now accept everything linux has to offer */
+ if (TREE_CODE(*node) != FIELD_DECL)
+ return NULL_TREE;
+
+ *no_add_attrs = false;
+ return NULL_TREE;
+}
+
+static struct attribute_spec user_attr = {
+ .name = "user",
+ .min_length = 0,
+ .max_length = 0,
+ .decl_required = false,
+ .type_required = false,
+ .function_type_required = false,
+ .handler = handle_user_attribute,
+#if BUILDING_GCC_VERSION >= 4007
+ .affects_type_identity = true
+#endif
+};
+
+static void register_attributes(void *event_data, void *data)
+{
+ register_attribute(&user_attr);
+}
+
+static tree get_field_type(tree field)
+{
+ return strip_array_types(TREE_TYPE(field));
+}
+
+static bool is_userspace_type(tree type)
+{
+ tree field;
+
+ for (field = TYPE_FIELDS(type); field; field = TREE_CHAIN(field)) {
+ tree fieldtype = get_field_type(field);
+ enum tree_code code = TREE_CODE(fieldtype);
+
+ if (code == RECORD_TYPE || code == UNION_TYPE)
+ if (is_userspace_type(fieldtype))
+ return true;
+
+ if (lookup_attribute("user", DECL_ATTRIBUTES(field)))
+ return true;
+ }
+ return false;
+}
+
+static void finish_type(void *event_data, void *data)
+{
+ tree type = (tree)event_data;
+
+ if (type == NULL_TREE || type == error_mark_node)
+ return;
+
+#if BUILDING_GCC_VERSION >= 5000
+ if (TREE_CODE(type) == ENUMERAL_TYPE)
+ return;
+#endif
+
+ if (TYPE_USERSPACE(type))
+ return;
+
+ if (is_userspace_type(type))
+ TYPE_USERSPACE(type) = 1;
+}
+
+static void initialize(tree var)
+{
+ basic_block bb;
+ gimple_stmt_iterator gsi;
+ tree initializer;
+ gimple init_stmt;
+
+ /* this is the original entry bb before the forced split */
+ bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
+
+ /* first check if variable is already initialized, warn otherwise */
+ for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) {
+ gimple stmt = gsi_stmt(gsi);
+ tree rhs1;
+
+ /* we're looking for an assignment of a single rhs... */
+ if (!gimple_assign_single_p(stmt))
+ continue;
+ rhs1 = gimple_assign_rhs1(stmt);
+#if BUILDING_GCC_VERSION >= 4007
+ /* ... of a non-clobbering expression... */
+ if (TREE_CLOBBER_P(rhs1))
+ continue;
+#endif
+ /* ... to our variable... */
+ if (gimple_get_lhs(stmt) != var)
+ continue;
+ /* if it's an initializer then we're good */
+ if (TREE_CODE(rhs1) == CONSTRUCTOR)
+ return;
+ }
+
+ /* these aren't the 0days you're looking for */
+ if (verbose)
+ inform(DECL_SOURCE_LOCATION(var),
+ "userspace variable will be forcibly initialized");
+
+ /* build the initializer expression */
+ initializer = build_constructor(TREE_TYPE(var), NULL);
+
+ /* build the initializer stmt */
+ init_stmt = gimple_build_assign(var, initializer);
+ gsi = gsi_after_labels(single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
+ gsi_insert_before(&gsi, init_stmt, GSI_NEW_STMT);
+ update_stmt(init_stmt);
+}
+
+static unsigned int structleak_execute(void)
+{
+ basic_block bb;
+ unsigned int ret = 0;
+ tree var;
+ unsigned int i;
+
+ /* split the first bb where we can put the forced initializers */
+ gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
+ bb = single_succ(ENTRY_BLOCK_PTR_FOR_FN(cfun));
+ if (!single_pred_p(bb)) {
+ split_edge(single_succ_edge(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
+ gcc_assert(single_succ_p(ENTRY_BLOCK_PTR_FOR_FN(cfun)));
+ }
+
+ /* enumerate all local variables and forcibly initialize our targets */
+ FOR_EACH_LOCAL_DECL(cfun, i, var) {
+ tree type = TREE_TYPE(var);
+
+ gcc_assert(DECL_P(var));
+ if (!auto_var_in_fn_p(var, current_function_decl))
+ continue;
+
+ /* only care about structure types */
+ if (TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE)
+ continue;
+
+ /* if the type is of interest, examine the variable */
+ if (TYPE_USERSPACE(type))
+ initialize(var);
+ }
+
+ return ret;
+}
+
+#define PASS_NAME structleak
+#define NO_GATE
+#define PROPERTIES_REQUIRED PROP_cfg
+#define TODO_FLAGS_FINISH TODO_verify_il | TODO_verify_ssa | TODO_verify_stmts | TODO_dump_func | TODO_remove_unused_locals | TODO_update_ssa | TODO_ggc_collect | TODO_verify_flow
+#include "gcc-generate-gimple-pass.h"
+
+__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
+{
+ int i;
+ 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;
+
+ PASS_INFO(structleak, "early_optimizations", 1, PASS_POS_INSERT_BEFORE);
+
+ if (!plugin_default_version_check(version, &gcc_version)) {
+ error(G_("incompatible gcc/plugin versions"));
+ return 1;
+ }
+
+ if (strncmp(lang_hooks.name, "GNU C", 5) && !strncmp(lang_hooks.name, "GNU C+", 6)) {
+ inform(UNKNOWN_LOCATION, G_("%s supports C only, not %s"), plugin_name, lang_hooks.name);
+ enable = false;
+ }
+
+ for (i = 0; i < argc; ++i) {
+ if (!strcmp(argv[i].key, "disable")) {
+ enable = false;
+ continue;
+ }
+ if (!strcmp(argv[i].key, "verbose")) {
+ verbose = true;
+ continue;
+ }
+ error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
+ }
+
+ register_callback(plugin_name, PLUGIN_INFO, NULL, &structleak_plugin_info);
+ if (enable) {
+ register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &structleak_pass_info);
+ register_callback(plugin_name, PLUGIN_FINISH_TYPE, finish_type, NULL);
+ }
+ register_callback(plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL);
+
+ return 0;
+}