11f5207b7SJohn Levon /*
21f5207b7SJohn Levon * Copyright (C) 2010 Dan Carpenter.
31f5207b7SJohn Levon *
41f5207b7SJohn Levon * This program is free software; you can redistribute it and/or
51f5207b7SJohn Levon * modify it under the terms of the GNU General Public License
61f5207b7SJohn Levon * as published by the Free Software Foundation; either version 2
71f5207b7SJohn Levon * of the License, or (at your option) any later version.
81f5207b7SJohn Levon *
91f5207b7SJohn Levon * This program is distributed in the hope that it will be useful,
101f5207b7SJohn Levon * but WITHOUT ANY WARRANTY; without even the implied warranty of
111f5207b7SJohn Levon * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
121f5207b7SJohn Levon * GNU General Public License for more details.
131f5207b7SJohn Levon *
141f5207b7SJohn Levon * You should have received a copy of the GNU General Public License
151f5207b7SJohn Levon * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
161f5207b7SJohn Levon */
171f5207b7SJohn Levon
181f5207b7SJohn Levon /*
191f5207b7SJohn Levon * check_memory() is getting too big and messy.
201f5207b7SJohn Levon *
211f5207b7SJohn Levon */
221f5207b7SJohn Levon
231f5207b7SJohn Levon #include <string.h>
241f5207b7SJohn Levon #include "smatch.h"
251f5207b7SJohn Levon #include "smatch_slist.h"
261f5207b7SJohn Levon #include "smatch_extra.h"
271f5207b7SJohn Levon
281f5207b7SJohn Levon static int my_id;
291f5207b7SJohn Levon
301f5207b7SJohn Levon STATE(freed);
311f5207b7SJohn Levon STATE(ok);
321f5207b7SJohn Levon
ok_to_use(struct sm_state * sm,struct expression * mod_expr)331f5207b7SJohn Levon static void ok_to_use(struct sm_state *sm, struct expression *mod_expr)
341f5207b7SJohn Levon {
351f5207b7SJohn Levon if (sm->state != &ok)
361f5207b7SJohn Levon set_state(my_id, sm->name, sm->sym, &ok);
371f5207b7SJohn Levon }
381f5207b7SJohn Levon
pre_merge_hook(struct sm_state * cur,struct sm_state * other)39*c85f09ccSJohn Levon static void pre_merge_hook(struct sm_state *cur, struct sm_state *other)
401f5207b7SJohn Levon {
411f5207b7SJohn Levon if (is_impossible_path())
42*c85f09ccSJohn Levon set_state(my_id, cur->name, cur->sym, &ok);
431f5207b7SJohn Levon }
441f5207b7SJohn Levon
is_freed(struct expression * expr)451f5207b7SJohn Levon static int is_freed(struct expression *expr)
461f5207b7SJohn Levon {
471f5207b7SJohn Levon struct sm_state *sm;
481f5207b7SJohn Levon
491f5207b7SJohn Levon sm = get_sm_state_expr(my_id, expr);
501f5207b7SJohn Levon if (sm && slist_has_state(sm->possible, &freed))
511f5207b7SJohn Levon return 1;
521f5207b7SJohn Levon return 0;
531f5207b7SJohn Levon }
541f5207b7SJohn Levon
match_symbol(struct expression * expr)551f5207b7SJohn Levon static void match_symbol(struct expression *expr)
561f5207b7SJohn Levon {
571f5207b7SJohn Levon struct expression *parent;
581f5207b7SJohn Levon char *name;
591f5207b7SJohn Levon
601f5207b7SJohn Levon if (is_impossible_path())
611f5207b7SJohn Levon return;
621f5207b7SJohn Levon if (__in_fake_parameter_assign)
631f5207b7SJohn Levon return;
641f5207b7SJohn Levon
651f5207b7SJohn Levon parent = expr_get_parent_expr(expr);
661f5207b7SJohn Levon while (parent && parent->type == EXPR_PREOP && parent->op == '(')
671f5207b7SJohn Levon parent = expr_get_parent_expr(parent);
681f5207b7SJohn Levon if (parent && parent->type == EXPR_PREOP && parent->op == '&')
691f5207b7SJohn Levon return;
701f5207b7SJohn Levon
711f5207b7SJohn Levon if (!is_freed(expr))
721f5207b7SJohn Levon return;
731f5207b7SJohn Levon name = expr_to_var(expr);
741f5207b7SJohn Levon sm_warning("'%s' was already freed.", name);
751f5207b7SJohn Levon free_string(name);
761f5207b7SJohn Levon }
771f5207b7SJohn Levon
match_dereferences(struct expression * expr)781f5207b7SJohn Levon static void match_dereferences(struct expression *expr)
791f5207b7SJohn Levon {
801f5207b7SJohn Levon char *name;
811f5207b7SJohn Levon
821f5207b7SJohn Levon if (__in_fake_parameter_assign)
831f5207b7SJohn Levon return;
841f5207b7SJohn Levon
851f5207b7SJohn Levon if (expr->type != EXPR_PREOP)
861f5207b7SJohn Levon return;
871f5207b7SJohn Levon
881f5207b7SJohn Levon if (is_impossible_path())
891f5207b7SJohn Levon return;
901f5207b7SJohn Levon
911f5207b7SJohn Levon expr = strip_expr(expr->unop);
921f5207b7SJohn Levon if (!is_freed(expr))
931f5207b7SJohn Levon return;
941f5207b7SJohn Levon name = expr_to_var(expr);
951f5207b7SJohn Levon sm_error("dereferencing freed memory '%s'", name);
961f5207b7SJohn Levon set_state_expr(my_id, expr, &ok);
971f5207b7SJohn Levon free_string(name);
981f5207b7SJohn Levon }
991f5207b7SJohn Levon
1001f5207b7SJohn Levon static int ignored_params[16];
1011f5207b7SJohn Levon
set_ignored_params(struct expression * call)1021f5207b7SJohn Levon static void set_ignored_params(struct expression *call)
1031f5207b7SJohn Levon {
1041f5207b7SJohn Levon struct expression *arg;
1051f5207b7SJohn Levon const char *p;
1061f5207b7SJohn Levon int i;
1071f5207b7SJohn Levon
1081f5207b7SJohn Levon memset(&ignored_params, 0, sizeof(ignored_params));
1091f5207b7SJohn Levon
1101f5207b7SJohn Levon i = -1;
1111f5207b7SJohn Levon FOR_EACH_PTR(call->args, arg) {
1121f5207b7SJohn Levon i++;
1131f5207b7SJohn Levon if (arg->type != EXPR_STRING)
1141f5207b7SJohn Levon continue;
1151f5207b7SJohn Levon goto found;
1161f5207b7SJohn Levon } END_FOR_EACH_PTR(arg);
1171f5207b7SJohn Levon
1181f5207b7SJohn Levon return;
1191f5207b7SJohn Levon
1201f5207b7SJohn Levon found:
1211f5207b7SJohn Levon i++;
1221f5207b7SJohn Levon p = arg->string->data;
1231f5207b7SJohn Levon while ((p = strchr(p, '%'))) {
1241f5207b7SJohn Levon if (i >= ARRAY_SIZE(ignored_params))
1251f5207b7SJohn Levon return;
1261f5207b7SJohn Levon p++;
1271f5207b7SJohn Levon if (*p == '%') {
1281f5207b7SJohn Levon p++;
1291f5207b7SJohn Levon continue;
1301f5207b7SJohn Levon }
1311f5207b7SJohn Levon if (*p == '.')
1321f5207b7SJohn Levon p++;
1331f5207b7SJohn Levon if (*p == '*')
1341f5207b7SJohn Levon i++;
1351f5207b7SJohn Levon if (*p == 'p')
1361f5207b7SJohn Levon ignored_params[i] = 1;
1371f5207b7SJohn Levon i++;
1381f5207b7SJohn Levon }
1391f5207b7SJohn Levon }
1401f5207b7SJohn Levon
is_free_func(struct expression * fn)1411f5207b7SJohn Levon static int is_free_func(struct expression *fn)
1421f5207b7SJohn Levon {
1431f5207b7SJohn Levon char *name;
1441f5207b7SJohn Levon int ret = 0;
1451f5207b7SJohn Levon
1461f5207b7SJohn Levon name = expr_to_str(fn);
1471f5207b7SJohn Levon if (!name)
1481f5207b7SJohn Levon return 0;
1491f5207b7SJohn Levon if (strstr(name, "free"))
1501f5207b7SJohn Levon ret = 1;
1511f5207b7SJohn Levon free_string(name);
1521f5207b7SJohn Levon
1531f5207b7SJohn Levon return ret;
1541f5207b7SJohn Levon }
1551f5207b7SJohn Levon
match_call(struct expression * expr)1561f5207b7SJohn Levon static void match_call(struct expression *expr)
1571f5207b7SJohn Levon {
1581f5207b7SJohn Levon struct expression *arg;
1591f5207b7SJohn Levon char *name;
1601f5207b7SJohn Levon int i;
1611f5207b7SJohn Levon
1621f5207b7SJohn Levon if (is_impossible_path())
1631f5207b7SJohn Levon return;
1641f5207b7SJohn Levon
1651f5207b7SJohn Levon set_ignored_params(expr);
1661f5207b7SJohn Levon
1671f5207b7SJohn Levon i = -1;
1681f5207b7SJohn Levon FOR_EACH_PTR(expr->args, arg) {
1691f5207b7SJohn Levon i++;
1701f5207b7SJohn Levon if (!is_pointer(arg))
1711f5207b7SJohn Levon continue;
1721f5207b7SJohn Levon if (!is_freed(arg))
1731f5207b7SJohn Levon continue;
1741f5207b7SJohn Levon if (ignored_params[i])
1751f5207b7SJohn Levon continue;
1761f5207b7SJohn Levon
1771f5207b7SJohn Levon name = expr_to_var(arg);
1781f5207b7SJohn Levon if (is_free_func(expr->fn))
1791f5207b7SJohn Levon sm_error("double free of '%s'", name);
1801f5207b7SJohn Levon else
1811f5207b7SJohn Levon sm_warning("passing freed memory '%s'", name);
1821f5207b7SJohn Levon set_state_expr(my_id, arg, &ok);
1831f5207b7SJohn Levon free_string(name);
1841f5207b7SJohn Levon } END_FOR_EACH_PTR(arg);
1851f5207b7SJohn Levon }
1861f5207b7SJohn Levon
match_return(struct expression * expr)1871f5207b7SJohn Levon static void match_return(struct expression *expr)
1881f5207b7SJohn Levon {
1891f5207b7SJohn Levon char *name;
1901f5207b7SJohn Levon
1911f5207b7SJohn Levon if (is_impossible_path())
1921f5207b7SJohn Levon return;
1931f5207b7SJohn Levon if (__in_fake_parameter_assign)
1941f5207b7SJohn Levon return;
1951f5207b7SJohn Levon
1961f5207b7SJohn Levon if (!expr)
1971f5207b7SJohn Levon return;
1981f5207b7SJohn Levon if (!is_freed(expr))
1991f5207b7SJohn Levon return;
2001f5207b7SJohn Levon
2011f5207b7SJohn Levon name = expr_to_var(expr);
2021f5207b7SJohn Levon sm_warning("returning freed memory '%s'", name);
2031f5207b7SJohn Levon set_state_expr(my_id, expr, &ok);
2041f5207b7SJohn Levon free_string(name);
2051f5207b7SJohn Levon }
2061f5207b7SJohn Levon
match_free(const char * fn,struct expression * expr,void * param)2071f5207b7SJohn Levon static void match_free(const char *fn, struct expression *expr, void *param)
2081f5207b7SJohn Levon {
2091f5207b7SJohn Levon struct expression *arg;
2101f5207b7SJohn Levon
2111f5207b7SJohn Levon if (is_impossible_path())
2121f5207b7SJohn Levon return;
2131f5207b7SJohn Levon
2141f5207b7SJohn Levon arg = get_argument_from_call_expr(expr->args, PTR_INT(param));
2151f5207b7SJohn Levon if (!arg)
2161f5207b7SJohn Levon return;
2171f5207b7SJohn Levon if (is_freed(arg)) {
2181f5207b7SJohn Levon char *name = expr_to_var(arg);
2191f5207b7SJohn Levon
2201f5207b7SJohn Levon sm_error("double free of '%s'", name);
2211f5207b7SJohn Levon free_string(name);
2221f5207b7SJohn Levon }
2231f5207b7SJohn Levon set_state_expr(my_id, arg, &freed);
2241f5207b7SJohn Levon }
2251f5207b7SJohn Levon
set_param_freed(struct expression * call,struct expression * arg,char * key,char * unused)2261f5207b7SJohn Levon static void set_param_freed(struct expression *call, struct expression *arg, char *key, char *unused)
2271f5207b7SJohn Levon {
2281f5207b7SJohn Levon struct symbol *sym;
2291f5207b7SJohn Levon char *name;
2301f5207b7SJohn Levon
2311f5207b7SJohn Levon name = get_variable_from_key(arg, key, &sym);
2321f5207b7SJohn Levon if (!name || !sym)
2331f5207b7SJohn Levon goto free;
2341f5207b7SJohn Levon
2351f5207b7SJohn Levon set_state(my_id, name, sym, &freed);
2361f5207b7SJohn Levon free:
2371f5207b7SJohn Levon free_string(name);
2381f5207b7SJohn Levon }
2391f5207b7SJohn Levon
parent_is_free_var_sym(const char * name,struct symbol * sym)2401f5207b7SJohn Levon int parent_is_free_var_sym(const char *name, struct symbol *sym)
2411f5207b7SJohn Levon {
2421f5207b7SJohn Levon char buf[256];
2431f5207b7SJohn Levon char *start;
2441f5207b7SJohn Levon char *end;
2451f5207b7SJohn Levon struct smatch_state *state;
2461f5207b7SJohn Levon
2471f5207b7SJohn Levon if (option_project == PROJ_KERNEL)
2481f5207b7SJohn Levon return parent_is_free_var_sym_strict(name, sym);
2491f5207b7SJohn Levon
2501f5207b7SJohn Levon strncpy(buf, name, sizeof(buf) - 1);
2511f5207b7SJohn Levon buf[sizeof(buf) - 1] = '\0';
2521f5207b7SJohn Levon
2531f5207b7SJohn Levon start = &buf[0];
2541f5207b7SJohn Levon while ((*start == '&'))
2551f5207b7SJohn Levon start++;
2561f5207b7SJohn Levon
2571f5207b7SJohn Levon while ((end = strrchr(start, '-'))) {
2581f5207b7SJohn Levon *end = '\0';
2591f5207b7SJohn Levon state = __get_state(my_id, start, sym);
2601f5207b7SJohn Levon if (state == &freed)
2611f5207b7SJohn Levon return 1;
2621f5207b7SJohn Levon }
2631f5207b7SJohn Levon return 0;
2641f5207b7SJohn Levon }
2651f5207b7SJohn Levon
parent_is_free(struct expression * expr)2661f5207b7SJohn Levon int parent_is_free(struct expression *expr)
2671f5207b7SJohn Levon {
2681f5207b7SJohn Levon struct symbol *sym;
2691f5207b7SJohn Levon char *var;
2701f5207b7SJohn Levon int ret = 0;
2711f5207b7SJohn Levon
2721f5207b7SJohn Levon expr = strip_expr(expr);
2731f5207b7SJohn Levon var = expr_to_var_sym(expr, &sym);
2741f5207b7SJohn Levon if (!var || !sym)
2751f5207b7SJohn Levon goto free;
2761f5207b7SJohn Levon ret = parent_is_free_var_sym(var, sym);
2771f5207b7SJohn Levon free:
2781f5207b7SJohn Levon free_string(var);
2791f5207b7SJohn Levon return ret;
2801f5207b7SJohn Levon }
2811f5207b7SJohn Levon
check_free(int id)2821f5207b7SJohn Levon void check_free(int id)
2831f5207b7SJohn Levon {
2841f5207b7SJohn Levon my_id = id;
2851f5207b7SJohn Levon
2861f5207b7SJohn Levon if (option_project == PROJ_KERNEL) {
2871f5207b7SJohn Levon /* The kernel use check_free_strict.c */
2881f5207b7SJohn Levon return;
2891f5207b7SJohn Levon }
2901f5207b7SJohn Levon
2911f5207b7SJohn Levon add_function_hook("free", &match_free, INT_PTR(0));
2921f5207b7SJohn Levon
2931f5207b7SJohn Levon if (option_spammy)
2941f5207b7SJohn Levon add_hook(&match_symbol, SYM_HOOK);
2951f5207b7SJohn Levon add_hook(&match_dereferences, DEREF_HOOK);
2961f5207b7SJohn Levon add_hook(&match_call, FUNCTION_CALL_HOOK);
2971f5207b7SJohn Levon add_hook(&match_return, RETURN_HOOK);
2981f5207b7SJohn Levon
2991f5207b7SJohn Levon add_modification_hook(my_id, &ok_to_use);
3001f5207b7SJohn Levon select_return_implies_hook(PARAM_FREED, &set_param_freed);
3011f5207b7SJohn Levon add_pre_merge_hook(my_id, &pre_merge_hook);
3021f5207b7SJohn Levon }
303