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편집 파일: randomize_layout_plugin.c

/* * 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 < 7) #error "The RANDSTRUCT plugin requires GCC 4.7 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") #define INFORM(loc, msg, ...) inform(loc, "randstruct: " msg, ##__VA_ARGS__) #define MISMATCH(loc, how, ...) INFORM(loc, "casting between randomized structure pointer types (" how "): %qT and %qT\n", __VA_ARGS__) __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" }; struct whitelist_entry { const char *pathname; const char *lhs; const char *rhs; }; static const struct whitelist_entry whitelist[] = { /* NIU overloads mapping with page struct */ { "drivers/net/ethernet/sun/niu.c", "page", "address_space" }, /* unix_skb_parms via UNIXCB() buffer */ { "net/unix/af_unix.c", "unix_skb_parms", "char" }, /* big_key payload.data struct splashing */ { "security/keys/big_key.c", "path", "void *" }, { } }; /* 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)); TYPE_ATTRIBUTES(variant) = tree_cons(get_identifier("designated_init"), 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); 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 (code == RECORD_TYPE || code == UNION_TYPE) { if (!is_pure_ops_struct(fieldtype)) return 0; continue; } if (!is_fptr(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; SET_DECL_ALIGN(decl, 0); SET_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 = { }; static struct attribute_spec no_randomize_layout_attr = { }; static struct attribute_spec randomize_considered_attr = { }; static struct attribute_spec randomize_performed_attr = { }; static void register_attributes(void *event_data, void *data) { randomize_layout_attr.name = "randomize_layout"; randomize_layout_attr.type_required = true; randomize_layout_attr.handler = handle_randomize_layout_attr; randomize_layout_attr.affects_type_identity = true; no_randomize_layout_attr.name = "no_randomize_layout"; no_randomize_layout_attr.type_required = true; no_randomize_layout_attr.handler = handle_randomize_layout_attr; no_randomize_layout_attr.affects_type_identity = true; randomize_considered_attr.name = "randomize_considered"; randomize_considered_attr.type_required = true; randomize_considered_attr.handler = handle_randomize_considered_attr; randomize_performed_attr.name = "randomize_performed"; randomize_performed_attr.type_required = true; randomize_performed_attr.handler = handle_randomize_performed_attr; 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; MISMATCH(DECL_SOURCE_LOCATION(var), "constructor\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); } } static bool type_name_eq(gimple stmt, const_tree type_tree, const char *wanted_name) { const char *type_name; if (type_tree == NULL_TREE) return false; switch (TREE_CODE(type_tree)) { case RECORD_TYPE: type_name = TYPE_NAME_POINTER(type_tree); break; case INTEGER_TYPE: if (TYPE_PRECISION(type_tree) == CHAR_TYPE_SIZE) type_name = "char"; else { INFORM(gimple_location(stmt), "found non-char INTEGER_TYPE cast comparison: %qT\n", type_tree); debug_tree(type_tree); return false; } break; case POINTER_TYPE: if (TREE_CODE(TREE_TYPE(type_tree)) == VOID_TYPE) { type_name = "void *"; break; } else { INFORM(gimple_location(stmt), "found non-void POINTER_TYPE cast comparison %qT\n", type_tree); debug_tree(type_tree); return false; } default: INFORM(gimple_location(stmt), "unhandled cast comparison: %qT\n", type_tree); debug_tree(type_tree); return false; } return strcmp(type_name, wanted_name) == 0; } static bool whitelisted_cast(gimple stmt, const_tree lhs_tree, const_tree rhs_tree) { const struct whitelist_entry *entry; expanded_location xloc = expand_location(gimple_location(stmt)); for (entry = whitelist; entry->pathname; entry++) { if (!strstr(xloc.file, entry->pathname)) continue; if (type_name_eq(stmt, lhs_tree, entry->lhs) && type_name_eq(stmt, rhs_tree, entry->rhs)) return true; } return false; } /* * 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 { if (!whitelisted_cast(stmt, ptr_lhs_type, ptr_rhs_type)) MISMATCH(gimple_location(stmt), "rhs", 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 { if (!whitelisted_cast(stmt, ptr_lhs_type, op0_type)) MISMATCH(gimple_location(stmt), "op0", 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 { if (!whitelisted_cast(stmt, ptr_lhs_type, ptr_rhs_type)) MISMATCH(gimple_location(stmt), "ssa", 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; }