@@ -207,6 +207,8 @@ r200_reg_safe.h
r300_reg_safe.h
r420_reg_safe.h
r600_reg_safe.h
+randomize_layout_hash.h
+randomize_layout_seed.h
recordmcount
relocs
rlim_names.h
@@ -483,6 +483,44 @@ config GCC_PLUGIN_STRUCTLEAK_VERBOSE
initialized. Since not all existing initializers are detected
by the plugin, this can produce false positive warnings.
+config GCC_PLUGIN_RANDSTRUCT
+ bool "Randomize layout of sensitive kernel structures"
+ depends on GCC_PLUGINS
+ select MODVERSIONS if MODULES
+ help
+ If you say Y here, the layouts of structures explicitly
+ marked by __randomize_layout will be randomized at
+ compile-time. This can introduce the requirement of an
+ additional information exposure vulnerability for exploits
+ targeting these structure types.
+
+ Enabling this feature will introduce some performance impact,
+ slightly increase memory usage, and prevent the use of forensic
+ tools like Volatility against the system (unless the kernel
+ source tree isn't cleaned after kernel installation).
+
+ The seed used for compilation is located at
+ scripts/gcc-plgins/randomize_layout_seed.h. It remains after
+ a make clean to allow for external modules to be compiled with
+ the existing seed and will be removed by a make mrproper or
+ make distclean.
+
+ Note that the implementation requires gcc 4.6.4. or newer.
+
+ This plugin was ported from grsecurity/PaX. More information at:
+ * https://grsecurity.net/
+ * https://pax.grsecurity.net/
+
+config GCC_PLUGIN_RANDSTRUCT_PERFORMANCE
+ bool "Use cacheline-aware structure randomization"
+ depends on GCC_PLUGIN_RANDSTRUCT
+ help
+ If you say Y here, the RANDSTRUCT randomization will make a
+ best effort at restricting randomization to cacheline-sized
+ groups of elements. It will further not randomize bitfields
+ in structures. This reduces the performance hit of RANDSTRUCT
+ at the cost of weakened randomization.
+
config HAVE_CC_STACKPROTECTOR
bool
help
@@ -245,6 +245,11 @@
/* Mark a function definition as prohibited from being cloned. */
#define __noclone __attribute__((__noclone__, __optimize__("no-tracer")))
+#ifdef RANDSTRUCT_PLUGIN
+#define __randomize_layout __attribute__((randomize_layout))
+#define __no_randomize_layout __attribute__((no_randomize_layout))
+#endif
+
#endif /* GCC_VERSION >= 40500 */
#if GCC_VERSION >= 40600
@@ -444,6 +444,14 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
# define __latent_entropy
#endif
+#ifndef __randomize_layout
+# define __randomize_layout
+#endif
+
+#ifndef __no_randomize_layout
+# define __no_randomize_layout
+#endif
+
#ifndef __nocapture
# define __nocapture(...)
#endif
@@ -24,10 +24,17 @@
#ifndef MODULE_ARCH_VERMAGIC
#define MODULE_ARCH_VERMAGIC ""
#endif
+#ifdef RANDSTRUCT_PLUGIN
+#include <generated/randomize_layout_hash.h>
+#define MODULE_RANDSTRUCT_PLUGIN "RANDSTRUCT_PLUGIN_" RANDSTRUCT_HASHED_SEED
+#else
+#define MODULE_RANDSTRUCT_PLUGIN
+#endif
#define VERMAGIC_STRING \
UTS_RELEASE " " \
MODULE_VERMAGIC_SMP MODULE_VERMAGIC_PREEMPT \
MODULE_VERMAGIC_MODULE_UNLOAD MODULE_VERMAGIC_MODVERSIONS \
- MODULE_ARCH_VERMAGIC
+ MODULE_ARCH_VERMAGIC \
+ MODULE_RANDSTRUCT_PLUGIN
@@ -1316,13 +1316,30 @@ static int check_version(Elf_Shdr *sechdrs,
goto bad_version;
}
+#ifdef CONFIG_GCC_PLUGIN_RANDSTRUCT
+ /*
+ * avoid potentially printing jibberish on attempted load
+ * of a module randomized with a different seed
+ */
+ pr_warn("no symbol version for %s\n", symname);
+#else
/* Broken toolchain. Warn once, then let it go.. */
- pr_warn_once("%s: no symbol version for %s\n", mod->name, symname);
+ pr_warn("%s: no symbol version for %s\n", mod->name, symname);
+#endif
return 1;
bad_version:
+#ifdef CONFIG_GCC_PLUGIN_RANDSTRUCT
+ /*
+ * avoid potentially printing jibberish on attempted load
+ * of a module randomized with a different seed
+ */
+ pr_warn("attempted module disagrees about version of symbol %s\n",
+ symname);
+#else
pr_warn("%s: disagrees about version of symbol %s\n",
mod->name, symname);
+#endif
return 0;
}
@@ -2964,7 +2981,15 @@ static struct module *setup_load_info(struct load_info *info, int flags)
mod = (void *)info->sechdrs[info->index.mod].sh_addr;
if (info->index.sym == 0) {
+#ifdef CONFIG_GCC_PLUGIN_RANDSTRUCT
+ /*
+ * avoid potentially printing jibberish on attempted load
+ * of a module randomized with a different seed
+ */
+ pr_warn("module has no symbols (stripped?)\n");
+#else
pr_warn("%s: module has no symbols (stripped?)\n", mod->name);
+#endif
return ERR_PTR(-ENOEXEC);
}
@@ -42,11 +42,16 @@ ifdef CONFIG_GCC_PLUGINS
gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK_VERBOSE) += -fplugin-arg-structleak_plugin-verbose
gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_STRUCTLEAK) += -DSTRUCTLEAK_PLUGIN
+ gcc-plugin-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) += randomize_layout_plugin.so
+ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT) += -DRANDSTRUCT_PLUGIN
+ gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_RANDSTRUCT_PERFORMANCE) += -fplugin-arg-randomize_layout_plugin-performance-mode
+
GCC_PLUGINS_CFLAGS := $(strip $(addprefix -fplugin=$(objtree)/scripts/gcc-plugins/, $(gcc-plugin-y)) $(gcc-plugin-cflags-y))
export PLUGINCC GCC_PLUGINS_CFLAGS GCC_PLUGIN GCC_PLUGIN_SUBDIR
export SANCOV_PLUGIN DISABLE_LATENT_ENTROPY_PLUGIN
export INITIFY_DISABLE_VERIFIY_NOCAPTURE_FUNCTIONS
+ export RANDSTRUCT_PLUGIN
ifneq ($(PLUGINCC),)
# SANCOV_PLUGIN can be only in CFLAGS_KCOV because avoid duplication.
new file mode 100644
@@ -0,0 +1 @@
+randomize_layout_seed.h
@@ -18,6 +18,14 @@ endif
export HOSTLIBS
+$(obj)/randomize_layout_plugin.o: $(objtree)/$(obj)/randomize_layout_seed.h
+quiet_cmd_create_randomize_layout_seed = GENSEED $@
+cmd_create_randomize_layout_seed = \
+ $(CONFIG_SHELL) $(srctree)/$(src)/gen-random-seed.sh $@ $(objtree)/include/generated/randomize_layout_hash.h
+$(objtree)/$(obj)/randomize_layout_seed.h: FORCE
+ $(call if_changed,create_randomize_layout_seed)
+targets = randomize_layout_seed.h randomize_layout_hash.h
+
$(HOSTLIBS)-y := $(foreach p,$(GCC_PLUGIN),$(if $(findstring /,$(p)),,$(p)))
always := $($(HOSTLIBS)-y)
new file mode 100644
@@ -0,0 +1,8 @@
+#!/bin/sh
+
+if [ ! -f "$1" ]; then
+ SEED=`od -A n -t x8 -N 32 /dev/urandom | tr -d ' \n'`
+ echo "const char *randstruct_seed = \"$SEED\";" > "$1"
+ HASH=`echo -n "$SEED" | sha256sum | cut -d" " -f1 | tr -d ' \n'`
+ echo "#define RANDSTRUCT_HASHED_SEED \"$HASH\"" > "$2"
+fi
new file mode 100644
@@ -0,0 +1,943 @@
+/*
+ * Copyright 2014-2016 by Open Source Security, Inc., Brad Spengler <spender@grsecurity.net>
+ * and 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
+ *
+ * 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 randomize_layout_plugin.so randomize_layout_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 randomize_layout_plugin.so randomize_layout_plugin.c
+ * $ gcc -fplugin=./randomize_layout_plugin.so test.c -O2
+ */
+
+#include "gcc-common.h"
+#include "randomize_layout_seed.h"
+
+#if BUILDING_GCC_MAJOR < 4 || (BUILDING_GCC_MAJOR == 4 && BUILDING_GCC_MINOR < 6) || \
+ (BUILDING_GCC_MAJOR == 4 && BUILDING_GCC_MINOR == 6 && BUILDING_GCC_PATCHLEVEL < 4)
+#error "The RANDSTRUCT plugin requires GCC 4.6.4 or newer."
+#endif
+
+#define ORIG_TYPE_NAME(node) \
+ (TYPE_NAME(TYPE_MAIN_VARIANT(node)) != NULL_TREE ? ((const unsigned char *)IDENTIFIER_POINTER(TYPE_NAME(TYPE_MAIN_VARIANT(node)))) : (const unsigned char *)"anonymous")
+
+__visible int plugin_is_GPL_compatible;
+
+static int performance_mode;
+
+static struct plugin_info randomize_layout_plugin_info = {
+ .version = "201402201816vanilla",
+ .help = "disable\t\t\tdo not activate plugin\n"
+ "performance-mode\tenable cacheline-aware layout randomization\n"
+};
+
+/* from old Linux dcache.h */
+static inline unsigned long
+partial_name_hash(unsigned long c, unsigned long prevhash)
+{
+ return (prevhash + (c << 4) + (c >> 4)) * 11;
+}
+static inline unsigned int
+name_hash(const unsigned char *name)
+{
+ unsigned long hash = 0;
+ unsigned int len = strlen((const char *)name);
+ while (len--)
+ hash = partial_name_hash(*name++, hash);
+ return (unsigned int)hash;
+}
+
+static tree handle_randomize_layout_attr(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
+{
+ tree type;
+
+ *no_add_attrs = true;
+ if (TREE_CODE(*node) == FUNCTION_DECL) {
+ error("%qE attribute does not apply to functions (%qF)", name, *node);
+ return NULL_TREE;
+ }
+
+ if (TREE_CODE(*node) == PARM_DECL) {
+ error("%qE attribute does not apply to function parameters (%qD)", name, *node);
+ return NULL_TREE;
+ }
+
+ if (TREE_CODE(*node) == VAR_DECL) {
+ error("%qE attribute does not apply to variables (%qD)", name, *node);
+ return NULL_TREE;
+ }
+
+ if (TYPE_P(*node)) {
+ type = *node;
+ } else {
+ gcc_assert(TREE_CODE(*node) == TYPE_DECL);
+ type = TREE_TYPE(*node);
+ }
+
+ if (TREE_CODE(type) != RECORD_TYPE) {
+ error("%qE attribute used on %qT applies to struct types only", name, type);
+ return NULL_TREE;
+ }
+
+ if (lookup_attribute(IDENTIFIER_POINTER(name), TYPE_ATTRIBUTES(type))) {
+ error("%qE attribute is already applied to the type %qT", name, type);
+ return NULL_TREE;
+ }
+
+ *no_add_attrs = false;
+
+ return NULL_TREE;
+}
+
+/* set on complete types that we don't need to inspect further at all */
+static tree handle_randomize_considered_attr(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
+{
+ *no_add_attrs = false;
+ return NULL_TREE;
+}
+
+/*
+ * set on types that we've performed a shuffle on, to prevent re-shuffling
+ * this does not preclude us from inspecting its fields for potential shuffles
+ */
+static tree handle_randomize_performed_attr(tree *node, tree name, tree args, int flags, bool *no_add_attrs)
+{
+ *no_add_attrs = false;
+ return NULL_TREE;
+}
+
+/*
+ * 64bit variant of Bob Jenkins' public domain PRNG
+ * 256 bits of internal state
+ */
+
+typedef unsigned long long u64;
+
+typedef struct ranctx { u64 a; u64 b; u64 c; u64 d; } ranctx;
+
+#define rot(x,k) (((x)<<(k))|((x)>>(64-(k))))
+static u64 ranval(ranctx *x) {
+ u64 e = x->a - rot(x->b, 7);
+ x->a = x->b ^ rot(x->c, 13);
+ x->b = x->c + rot(x->d, 37);
+ x->c = x->d + e;
+ x->d = e + x->a;
+ return x->d;
+}
+
+static void raninit(ranctx *x, u64 *seed) {
+ int i;
+
+ x->a = seed[0];
+ x->b = seed[1];
+ x->c = seed[2];
+ x->d = seed[3];
+
+ for (i=0; i < 30; ++i)
+ (void)ranval(x);
+}
+
+static u64 shuffle_seed[4];
+
+struct partition_group {
+ tree tree_start;
+ unsigned long start;
+ unsigned long length;
+};
+
+static void partition_struct(tree *fields, unsigned long length, struct partition_group *size_groups, unsigned long *num_groups)
+{
+ unsigned long i;
+ unsigned long accum_size = 0;
+ unsigned long accum_length = 0;
+ unsigned long group_idx = 0;
+
+ gcc_assert(length < INT_MAX);
+
+ memset(size_groups, 0, sizeof(struct partition_group) * length);
+
+ for (i = 0; i < length; i++) {
+ if (size_groups[group_idx].tree_start == NULL_TREE) {
+ size_groups[group_idx].tree_start = fields[i];
+ size_groups[group_idx].start = i;
+ accum_length = 0;
+ accum_size = 0;
+ }
+ accum_size += (unsigned long)int_size_in_bytes(TREE_TYPE(fields[i]));
+ accum_length++;
+ if (accum_size >= 64) {
+ size_groups[group_idx].length = accum_length;
+ accum_length = 0;
+ group_idx++;
+ }
+ }
+
+ if (size_groups[group_idx].tree_start != NULL_TREE &&
+ !size_groups[group_idx].length) {
+ size_groups[group_idx].length = accum_length;
+ group_idx++;
+ }
+
+ *num_groups = group_idx;
+}
+
+static void performance_shuffle(tree *newtree, unsigned long length, ranctx *prng_state)
+{
+ unsigned long i, x;
+ struct partition_group size_group[length];
+ unsigned long num_groups = 0;
+ unsigned long randnum;
+
+ partition_struct(newtree, length, (struct partition_group *)&size_group, &num_groups);
+ for (i = num_groups - 1; i > 0; i--) {
+ struct partition_group tmp;
+ randnum = ranval(prng_state) % (i + 1);
+ tmp = size_group[i];
+ size_group[i] = size_group[randnum];
+ size_group[randnum] = tmp;
+ }
+
+ for (x = 0; x < num_groups; x++) {
+ for (i = size_group[x].start + size_group[x].length - 1; i > size_group[x].start; i--) {
+ tree tmp;
+ if (DECL_BIT_FIELD_TYPE(newtree[i]))
+ continue;
+ randnum = ranval(prng_state) % (i + 1);
+ // we could handle this case differently if desired
+ if (DECL_BIT_FIELD_TYPE(newtree[randnum]))
+ continue;
+ tmp = newtree[i];
+ newtree[i] = newtree[randnum];
+ newtree[randnum] = tmp;
+ }
+ }
+}
+
+static void full_shuffle(tree *newtree, unsigned long length, ranctx *prng_state)
+{
+ unsigned long i, randnum;
+
+ for (i = length - 1; i > 0; i--) {
+ tree tmp;
+ randnum = ranval(prng_state) % (i + 1);
+ tmp = newtree[i];
+ newtree[i] = newtree[randnum];
+ newtree[randnum] = tmp;
+ }
+}
+
+/* modern in-place Fisher-Yates shuffle */
+static void shuffle(const_tree type, tree *newtree, unsigned long length)
+{
+ unsigned long i;
+ u64 seed[4];
+ ranctx prng_state;
+ const unsigned char *structname;
+
+ if (length == 0)
+ return;
+
+ gcc_assert(TREE_CODE(type) == RECORD_TYPE);
+
+ structname = ORIG_TYPE_NAME(type);
+
+#ifdef __DEBUG_PLUGIN
+ fprintf(stderr, "Shuffling struct %s %p\n", (const char *)structname, type);
+#ifdef __DEBUG_VERBOSE
+ debug_tree((tree)type);
+#endif
+#endif
+
+ for (i = 0; i < 4; i++) {
+ seed[i] = shuffle_seed[i];
+ seed[i] ^= name_hash(structname);
+ }
+
+ raninit(&prng_state, (u64 *)&seed);
+
+ if (performance_mode)
+ performance_shuffle(newtree, length, &prng_state);
+ else
+ full_shuffle(newtree, length, &prng_state);
+}
+
+static bool is_flexible_array(const_tree field)
+{
+ const_tree fieldtype;
+ const_tree typesize;
+ const_tree elemtype;
+ const_tree elemsize;
+
+ fieldtype = TREE_TYPE(field);
+ typesize = TYPE_SIZE(fieldtype);
+
+ if (TREE_CODE(fieldtype) != ARRAY_TYPE)
+ return false;
+
+ elemtype = TREE_TYPE(fieldtype);
+ elemsize = TYPE_SIZE(elemtype);
+
+ /* size of type is represented in bits */
+
+ if (typesize == NULL_TREE && TYPE_DOMAIN(fieldtype) != NULL_TREE &&
+ TYPE_MAX_VALUE(TYPE_DOMAIN(fieldtype)) == NULL_TREE)
+ return true;
+
+ if (typesize != NULL_TREE &&
+ (TREE_CONSTANT(typesize) && (!tree_to_uhwi(typesize) ||
+ tree_to_uhwi(typesize) == tree_to_uhwi(elemsize))))
+ return true;
+
+ return false;
+}
+
+static int relayout_struct(tree type)
+{
+ unsigned long num_fields = (unsigned long)list_length(TYPE_FIELDS(type));
+ unsigned long shuffle_length = num_fields;
+ tree field;
+ tree newtree[num_fields];
+ unsigned long i;
+ tree list;
+ tree variant;
+ tree main_variant;
+ expanded_location xloc;
+ bool has_flexarray = false;
+
+ if (TYPE_FIELDS(type) == NULL_TREE)
+ return 0;
+
+ if (num_fields < 2)
+ return 0;
+
+ gcc_assert(TREE_CODE(type) == RECORD_TYPE);
+
+ gcc_assert(num_fields < INT_MAX);
+
+ if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(type)) ||
+ lookup_attribute("no_randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type))))
+ return 0;
+
+ /* Workaround for 3rd-party VirtualBox source that we can't modify ourselves */
+ if (!strcmp((const char *)ORIG_TYPE_NAME(type), "INTNETTRUNKFACTORY") ||
+ !strcmp((const char *)ORIG_TYPE_NAME(type), "RAWPCIFACTORY"))
+ return 0;
+
+ /* throw out any structs in uapi */
+ xloc = expand_location(DECL_SOURCE_LOCATION(TYPE_FIELDS(type)));
+
+ if (strstr(xloc.file, "/uapi/"))
+ error(G_("attempted to randomize userland API struct %s"), ORIG_TYPE_NAME(type));
+
+ for (field = TYPE_FIELDS(type), i = 0; field; field = TREE_CHAIN(field), i++) {
+ gcc_assert(TREE_CODE(field) == FIELD_DECL);
+ newtree[i] = field;
+ }
+
+ /*
+ * enforce that we don't randomize the layout of the last
+ * element of a struct if it's a 0 or 1-length array
+ * or a proper flexible array
+ */
+ if (is_flexible_array(newtree[num_fields - 1])) {
+ has_flexarray = true;
+ shuffle_length--;
+ }
+
+ shuffle(type, (tree *)newtree, shuffle_length);
+
+ /*
+ * set up a bogus anonymous struct field designed to error out on unnamed struct initializers
+ * as gcc provides no other way to detect such code
+ */
+ list = make_node(FIELD_DECL);
+ TREE_CHAIN(list) = newtree[0];
+ TREE_TYPE(list) = void_type_node;
+ DECL_SIZE(list) = bitsize_zero_node;
+ DECL_NONADDRESSABLE_P(list) = 1;
+ DECL_FIELD_BIT_OFFSET(list) = bitsize_zero_node;
+ DECL_SIZE_UNIT(list) = size_zero_node;
+ DECL_FIELD_OFFSET(list) = size_zero_node;
+ DECL_CONTEXT(list) = type;
+ // to satisfy the constify plugin
+ TREE_READONLY(list) = 1;
+
+ for (i = 0; i < num_fields - 1; i++)
+ TREE_CHAIN(newtree[i]) = newtree[i+1];
+ TREE_CHAIN(newtree[num_fields - 1]) = NULL_TREE;
+
+ main_variant = TYPE_MAIN_VARIANT(type);
+ for (variant = main_variant; variant; variant = TYPE_NEXT_VARIANT(variant)) {
+ TYPE_FIELDS(variant) = list;
+ TYPE_ATTRIBUTES(variant) = copy_list(TYPE_ATTRIBUTES(variant));
+ TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("randomize_performed"), NULL_TREE, TYPE_ATTRIBUTES(variant));
+ if (has_flexarray)
+ TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("has_flexarray"), NULL_TREE, TYPE_ATTRIBUTES(type));
+ }
+
+ /*
+ * force a re-layout of the main variant
+ * the TYPE_SIZE for all variants will be recomputed
+ * by finalize_type_size()
+ */
+ TYPE_SIZE(main_variant) = NULL_TREE;
+ layout_type(main_variant);
+ gcc_assert(TYPE_SIZE(main_variant) != NULL_TREE);
+
+ return 1;
+}
+
+/* from constify plugin */
+static const_tree get_field_type(const_tree field)
+{
+ return strip_array_types(TREE_TYPE(field));
+}
+
+/* from constify plugin */
+static bool is_fptr(const_tree fieldtype)
+{
+ if (TREE_CODE(fieldtype) != POINTER_TYPE)
+ return false;
+
+ return TREE_CODE(TREE_TYPE(fieldtype)) == FUNCTION_TYPE;
+}
+
+/* derived from constify plugin */
+static int is_pure_ops_struct(const_tree node)
+{
+ const_tree field;
+
+ gcc_assert(TREE_CODE(node) == RECORD_TYPE || TREE_CODE(node) == UNION_TYPE);
+
+ /* XXX: Do not apply randomization to all-ftpr structs yet. */
+ return 0;
+
+ for (field = TYPE_FIELDS(node); field; field = TREE_CHAIN(field)) {
+ const_tree fieldtype = get_field_type(field);
+ enum tree_code code = TREE_CODE(fieldtype);
+
+ if (node == fieldtype)
+ continue;
+
+ if (!is_fptr(fieldtype))
+ return 0;
+
+ if (code != RECORD_TYPE && code != UNION_TYPE)
+ continue;
+
+ if (!is_pure_ops_struct(fieldtype))
+ return 0;
+ }
+
+ return 1;
+}
+
+static void randomize_type(tree type)
+{
+ tree variant;
+
+ gcc_assert(TREE_CODE(type) == RECORD_TYPE);
+
+ if (lookup_attribute("randomize_considered", TYPE_ATTRIBUTES(type)))
+ return;
+
+ if (lookup_attribute("randomize_layout", TYPE_ATTRIBUTES(TYPE_MAIN_VARIANT(type))) || is_pure_ops_struct(type))
+ relayout_struct(type);
+
+ for (variant = TYPE_MAIN_VARIANT(type); variant; variant = TYPE_NEXT_VARIANT(variant)) {
+ TYPE_ATTRIBUTES(type) = copy_list(TYPE_ATTRIBUTES(type));
+ TYPE_ATTRIBUTES(type) = tree_cons(get_identifier("randomize_considered"), NULL_TREE, TYPE_ATTRIBUTES(type));
+ }
+#ifdef __DEBUG_PLUGIN
+ fprintf(stderr, "Marking randomize_considered on struct %s\n", ORIG_TYPE_NAME(type));
+#ifdef __DEBUG_VERBOSE
+ debug_tree(type);
+#endif
+#endif
+}
+
+static void update_decl_size(tree decl)
+{
+ tree lastval, lastidx, field, init, type, flexsize;
+ unsigned HOST_WIDE_INT len;
+
+ type = TREE_TYPE(decl);
+
+ if (!lookup_attribute("has_flexarray", TYPE_ATTRIBUTES(type)))
+ return;
+
+ init = DECL_INITIAL(decl);
+ if (init == NULL_TREE || init == error_mark_node)
+ return;
+
+ if (TREE_CODE(init) != CONSTRUCTOR)
+ return;
+
+ len = CONSTRUCTOR_NELTS(init);
+ if (!len)
+ return;
+
+ lastval = CONSTRUCTOR_ELT(init, CONSTRUCTOR_NELTS(init) - 1)->value;
+ lastidx = CONSTRUCTOR_ELT(init, CONSTRUCTOR_NELTS(init) - 1)->index;
+
+ for (field = TYPE_FIELDS(TREE_TYPE(decl)); TREE_CHAIN(field); field = TREE_CHAIN(field))
+ ;
+
+ if (lastidx != field)
+ return;
+
+ if (TREE_CODE(lastval) != STRING_CST) {
+ error("Only string constants are supported as initializers "
+ "for randomized structures with flexible arrays");
+ return;
+ }
+
+ flexsize = bitsize_int(TREE_STRING_LENGTH(lastval) *
+ tree_to_uhwi(TYPE_SIZE(TREE_TYPE(TREE_TYPE(lastval)))));
+
+ DECL_SIZE(decl) = size_binop(PLUS_EXPR, TYPE_SIZE(type), flexsize);
+
+ return;
+}
+
+
+static void randomize_layout_finish_decl(void *event_data, void *data)
+{
+ tree decl = (tree)event_data;
+ tree type;
+
+ if (decl == NULL_TREE || decl == error_mark_node)
+ return;
+
+ type = TREE_TYPE(decl);
+
+ if (TREE_CODE(decl) != VAR_DECL)
+ return;
+
+ if (TREE_CODE(type) != RECORD_TYPE && TREE_CODE(type) != UNION_TYPE)
+ return;
+
+ if (!lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(type)))
+ return;
+
+ DECL_SIZE(decl) = 0;
+ DECL_SIZE_UNIT(decl) = 0;
+ DECL_ALIGN(decl) = 0;
+ DECL_MODE (decl) = VOIDmode;
+ SET_DECL_RTL(decl, 0);
+ update_decl_size(decl);
+ layout_decl(decl, 0);
+}
+
+static void finish_type(void *event_data, void *data)
+{
+ tree type = (tree)event_data;
+
+ if (type == NULL_TREE || type == error_mark_node)
+ return;
+
+ if (TREE_CODE(type) != RECORD_TYPE)
+ return;
+
+ if (TYPE_FIELDS(type) == NULL_TREE)
+ return;
+
+ if (lookup_attribute("randomize_considered", TYPE_ATTRIBUTES(type)))
+ return;
+
+#ifdef __DEBUG_PLUGIN
+ fprintf(stderr, "Calling randomize_type on %s\n", ORIG_TYPE_NAME(type));
+#endif
+#ifdef __DEBUG_VERBOSE
+ debug_tree(type);
+#endif
+ randomize_type(type);
+
+ return;
+}
+
+static struct attribute_spec randomize_layout_attr = {
+ .name = "randomize_layout",
+ // related to args
+ .min_length = 0,
+ .max_length = 0,
+ .decl_required = false,
+ // need type declaration
+ .type_required = true,
+ .function_type_required = false,
+ .handler = handle_randomize_layout_attr,
+#if BUILDING_GCC_VERSION >= 4007
+ .affects_type_identity = true
+#endif
+};
+
+static struct attribute_spec no_randomize_layout_attr = {
+ .name = "no_randomize_layout",
+ // related to args
+ .min_length = 0,
+ .max_length = 0,
+ .decl_required = false,
+ // need type declaration
+ .type_required = true,
+ .function_type_required = false,
+ .handler = handle_randomize_layout_attr,
+#if BUILDING_GCC_VERSION >= 4007
+ .affects_type_identity = true
+#endif
+};
+
+static struct attribute_spec randomize_considered_attr = {
+ .name = "randomize_considered",
+ // related to args
+ .min_length = 0,
+ .max_length = 0,
+ .decl_required = false,
+ // need type declaration
+ .type_required = true,
+ .function_type_required = false,
+ .handler = handle_randomize_considered_attr,
+#if BUILDING_GCC_VERSION >= 4007
+ .affects_type_identity = false
+#endif
+};
+
+static struct attribute_spec randomize_performed_attr = {
+ .name = "randomize_performed",
+ // related to args
+ .min_length = 0,
+ .max_length = 0,
+ .decl_required = false,
+ // need type declaration
+ .type_required = true,
+ .function_type_required = false,
+ .handler = handle_randomize_performed_attr,
+#if BUILDING_GCC_VERSION >= 4007
+ .affects_type_identity = false
+#endif
+};
+
+static void register_attributes(void *event_data, void *data)
+{
+ register_attribute(&randomize_layout_attr);
+ register_attribute(&no_randomize_layout_attr);
+ register_attribute(&randomize_considered_attr);
+ register_attribute(&randomize_performed_attr);
+}
+
+static void check_bad_casts_in_constructor(tree var, tree init)
+{
+ unsigned HOST_WIDE_INT idx;
+ tree field, val;
+ tree field_type, val_type;
+
+ FOR_EACH_CONSTRUCTOR_ELT(CONSTRUCTOR_ELTS(init), idx, field, val) {
+ if (TREE_CODE(val) == CONSTRUCTOR) {
+ check_bad_casts_in_constructor(var, val);
+ continue;
+ }
+
+ /* pipacs' plugin creates franken-arrays that differ from those produced by
+ normal code which all have valid 'field' trees. work around this */
+ if (field == NULL_TREE)
+ continue;
+ field_type = TREE_TYPE(field);
+ val_type = TREE_TYPE(val);
+
+ if (TREE_CODE(field_type) != POINTER_TYPE || TREE_CODE(val_type) != POINTER_TYPE)
+ continue;
+
+ if (field_type == val_type)
+ continue;
+
+ field_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(field_type))));
+ val_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(val_type))));
+
+ if (field_type == void_type_node)
+ continue;
+ if (field_type == val_type)
+ continue;
+ if (TREE_CODE(val_type) != RECORD_TYPE)
+ continue;
+
+ if (!lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(val_type)))
+ continue;
+ inform(DECL_SOURCE_LOCATION(var), "found mismatched struct pointer types: %qT and %qT\n", TYPE_MAIN_VARIANT(field_type), TYPE_MAIN_VARIANT(val_type));
+ }
+}
+
+/* derived from the constify plugin */
+static void check_global_variables(void *event_data, void *data)
+{
+ struct varpool_node *node;
+ tree init;
+
+ FOR_EACH_VARIABLE(node) {
+ tree var = NODE_DECL(node);
+ init = DECL_INITIAL(var);
+ if (init == NULL_TREE)
+ continue;
+
+ if (TREE_CODE(init) != CONSTRUCTOR)
+ continue;
+
+ check_bad_casts_in_constructor(var, init);
+ }
+}
+
+static bool dominated_by_is_err(const_tree rhs, basic_block bb)
+{
+ basic_block dom;
+ gimple dom_stmt;
+ gimple call_stmt;
+ const_tree dom_lhs;
+ const_tree poss_is_err_cond;
+ const_tree poss_is_err_func;
+ const_tree is_err_arg;
+
+ dom = get_immediate_dominator(CDI_DOMINATORS, bb);
+ if (!dom)
+ return false;
+
+ dom_stmt = last_stmt(dom);
+ if (!dom_stmt)
+ return false;
+
+ if (gimple_code(dom_stmt) != GIMPLE_COND)
+ return false;
+
+ if (gimple_cond_code(dom_stmt) != NE_EXPR)
+ return false;
+
+ if (!integer_zerop(gimple_cond_rhs(dom_stmt)))
+ return false;
+
+ poss_is_err_cond = gimple_cond_lhs(dom_stmt);
+
+ if (TREE_CODE(poss_is_err_cond) != SSA_NAME)
+ return false;
+
+ call_stmt = SSA_NAME_DEF_STMT(poss_is_err_cond);
+
+ if (gimple_code(call_stmt) != GIMPLE_CALL)
+ return false;
+
+ dom_lhs = gimple_get_lhs(call_stmt);
+ poss_is_err_func = gimple_call_fndecl(call_stmt);
+ if (!poss_is_err_func)
+ return false;
+ if (dom_lhs != poss_is_err_cond)
+ return false;
+ if (strcmp(DECL_NAME_POINTER(poss_is_err_func), "IS_ERR"))
+ return false;
+
+ is_err_arg = gimple_call_arg(call_stmt, 0);
+ if (!is_err_arg)
+ return false;
+
+ if (is_err_arg != rhs)
+ return false;
+
+ return true;
+}
+
+static void handle_local_var_initializers(void)
+{
+ tree var;
+ unsigned int i;
+
+ FOR_EACH_LOCAL_DECL(cfun, i, var) {
+ tree init = DECL_INITIAL(var);
+ if (!init)
+ continue;
+ if (TREE_CODE(init) != CONSTRUCTOR)
+ continue;
+ check_bad_casts_in_constructor(var, init);
+ }
+}
+
+/*
+ * iterate over all statements to find "bad" casts:
+ * those where the address of the start of a structure is cast
+ * to a pointer of a structure of a different type, or a
+ * structure pointer type is cast to a different structure pointer type
+ */
+static unsigned int find_bad_casts_execute(void)
+{
+ basic_block bb;
+
+ handle_local_var_initializers();
+
+ FOR_EACH_BB_FN(bb, cfun) {
+ gimple_stmt_iterator gsi;
+
+ for (gsi = gsi_start_bb(bb); !gsi_end_p(gsi); gsi_next(&gsi)) {
+ gimple stmt;
+ const_tree lhs;
+ const_tree lhs_type;
+ const_tree rhs1;
+ const_tree rhs_type;
+ const_tree ptr_lhs_type;
+ const_tree ptr_rhs_type;
+ const_tree op0;
+ const_tree op0_type;
+ enum tree_code rhs_code;
+
+ stmt = gsi_stmt(gsi);
+
+#ifdef __DEBUG_PLUGIN
+#ifdef __DEBUG_VERBOSE
+ debug_gimple_stmt(stmt);
+ debug_tree(gimple_get_lhs(stmt));
+#endif
+#endif
+
+ if (gimple_code(stmt) != GIMPLE_ASSIGN)
+ continue;
+
+#ifdef __DEBUG_PLUGIN
+#ifdef __DEBUG_VERBOSE
+ debug_tree(gimple_assign_rhs1(stmt));
+#endif
+#endif
+
+ rhs_code = gimple_assign_rhs_code(stmt);
+
+ if (rhs_code != ADDR_EXPR && rhs_code != SSA_NAME)
+ continue;
+
+ lhs = gimple_get_lhs(stmt);
+ lhs_type = TREE_TYPE(lhs);
+ rhs1 = gimple_assign_rhs1(stmt);
+ rhs_type = TREE_TYPE(rhs1);
+
+ if (TREE_CODE(rhs_type) != POINTER_TYPE ||
+ TREE_CODE(lhs_type) != POINTER_TYPE)
+ continue;
+
+ ptr_lhs_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(lhs_type))));
+ ptr_rhs_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(rhs_type))));
+
+ if (ptr_rhs_type == void_type_node)
+ continue;
+
+ if (ptr_lhs_type == void_type_node)
+ continue;
+
+ if (dominated_by_is_err(rhs1, bb))
+ continue;
+
+ if (TREE_CODE(ptr_rhs_type) != RECORD_TYPE) {
+#ifndef __DEBUG_PLUGIN
+ if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_lhs_type)))
+#endif
+ inform(gimple_location(stmt), "found mismatched struct pointer types: %qT and %qT\n", ptr_lhs_type, ptr_rhs_type);
+ continue;
+ }
+
+ if (rhs_code == SSA_NAME && ptr_lhs_type == ptr_rhs_type)
+ continue;
+
+ if (rhs_code == ADDR_EXPR) {
+ op0 = TREE_OPERAND(rhs1, 0);
+
+ if (op0 == NULL_TREE)
+ continue;
+
+ if (TREE_CODE(op0) != VAR_DECL)
+ continue;
+
+ op0_type = TYPE_MAIN_VARIANT(strip_array_types(TYPE_MAIN_VARIANT(TREE_TYPE(op0))));
+ if (op0_type == ptr_lhs_type)
+ continue;
+
+#ifndef __DEBUG_PLUGIN
+ if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(op0_type)))
+#endif
+ inform(gimple_location(stmt), "found mismatched struct pointer types: %qT and %qT\n", ptr_lhs_type, op0_type);
+ } else {
+ const_tree ssa_name_var = SSA_NAME_VAR(rhs1);
+ /* skip bogus type casts introduced by container_of */
+ if (ssa_name_var != NULL_TREE && DECL_NAME(ssa_name_var) &&
+ !strcmp((const char *)DECL_NAME_POINTER(ssa_name_var), "__mptr"))
+ continue;
+#ifndef __DEBUG_PLUGIN
+ if (lookup_attribute("randomize_performed", TYPE_ATTRIBUTES(ptr_rhs_type)))
+#endif
+ inform(gimple_location(stmt), "found mismatched struct pointer types: %qT and %qT\n", ptr_lhs_type, ptr_rhs_type);
+ }
+
+ }
+ }
+ return 0;
+}
+
+#define PASS_NAME find_bad_casts
+#define NO_GATE
+#define TODO_FLAGS_FINISH TODO_dump_func
+#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;
+ int obtained_seed = 0;
+ struct register_pass_info find_bad_casts_pass_info;
+
+ find_bad_casts_pass_info.pass = make_find_bad_casts_pass();
+ find_bad_casts_pass_info.reference_pass_name = "ssa";
+ find_bad_casts_pass_info.ref_pass_instance_number = 1;
+ find_bad_casts_pass_info.pos_op = PASS_POS_INSERT_AFTER;
+
+ 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, "performance-mode")) {
+ performance_mode = 1;
+ continue;
+ }
+ error(G_("unknown option '-fplugin-arg-%s-%s'"), plugin_name, argv[i].key);
+ }
+
+ if (strlen(randstruct_seed) != 64) {
+ error(G_("invalid seed value supplied for %s plugin"), plugin_name);
+ return 1;
+ }
+ obtained_seed = sscanf(randstruct_seed, "%016llx%016llx%016llx%016llx",
+ &shuffle_seed[0], &shuffle_seed[1], &shuffle_seed[2], &shuffle_seed[3]);
+ if (obtained_seed != 4) {
+ error(G_("Invalid seed supplied for %s plugin"), plugin_name);
+ return 1;
+ }
+
+ register_callback(plugin_name, PLUGIN_INFO, NULL, &randomize_layout_plugin_info);
+ if (enable) {
+ register_callback(plugin_name, PLUGIN_ALL_IPA_PASSES_START, check_global_variables, NULL);
+ register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &find_bad_casts_pass_info);
+ register_callback(plugin_name, PLUGIN_FINISH_TYPE, finish_type, NULL);
+ register_callback(plugin_name, PLUGIN_FINISH_DECL, randomize_layout_finish_decl, NULL);
+ }
+ register_callback(plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL);
+
+ return 0;
+}