1 /*
2 * Copyright (C) 2010 Dan Carpenter.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version 2
7 * of the License, or (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
16 */
17
18 /*
19 * This is a kernel check to make sure we unwind everything on
20 * on errors.
21 *
22 */
23
24 #include "smatch.h"
25 #include "smatch_extra.h"
26 #include "smatch_slist.h"
27
28 #define EBUSY 16
29 #define MAX_ERRNO 4095
30
31 static int my_id;
32
33 STATE(allocated);
34 STATE(unallocated);
35
36 /* state of unwind function */
37 STATE(called);
38
was_passed_as_param(struct expression * expr)39 static int was_passed_as_param(struct expression *expr)
40 {
41 char *name;
42 struct symbol *sym;
43 struct symbol *arg;
44
45 name = expr_to_var_sym(expr, &sym);
46 if (!name)
47 return 0;
48 free_string(name);
49
50 FOR_EACH_PTR(cur_func_sym->ctype.base_type->arguments, arg) {
51 if (arg == sym)
52 return 1;
53 } END_FOR_EACH_PTR(arg);
54 return 0;
55 }
56
print_unwind_functions(const char * fn,struct expression * expr,void * _arg_no)57 static void print_unwind_functions(const char *fn, struct expression *expr, void *_arg_no)
58 {
59 struct expression *arg_expr;
60 int arg_no = PTR_INT(_arg_no);
61 static struct symbol *last_printed = NULL;
62
63 arg_expr = get_argument_from_call_expr(expr->args, arg_no);
64 if (!was_passed_as_param(arg_expr))
65 return;
66 if (last_printed == cur_func_sym)
67 return;
68 last_printed = cur_func_sym;
69 sm_msg("info: is unwind function");
70 }
71
request_granted(const char * fn,struct expression * call_expr,struct expression * assign_expr,void * _arg_no)72 static void request_granted(const char *fn, struct expression *call_expr,
73 struct expression *assign_expr, void *_arg_no)
74 {
75 struct expression *arg_expr;
76 int arg_no = PTR_INT(_arg_no);
77
78 if (arg_no == -1) {
79 if (!assign_expr)
80 return;
81 arg_expr = assign_expr->left;
82 } else {
83 arg_expr = get_argument_from_call_expr(call_expr->args, arg_no);
84 }
85 set_state_expr(my_id, arg_expr, &allocated);
86 }
87
request_denied(const char * fn,struct expression * call_expr,struct expression * assign_expr,void * _arg_no)88 static void request_denied(const char *fn, struct expression *call_expr,
89 struct expression *assign_expr, void *_arg_no)
90 {
91 struct expression *arg_expr;
92 int arg_no = PTR_INT(_arg_no);
93
94 if (arg_no == -1) {
95 if (!assign_expr)
96 return;
97 arg_expr = assign_expr->left;
98 } else {
99 arg_expr = get_argument_from_call_expr(call_expr->args, arg_no);
100 }
101 set_state_expr(my_id, arg_expr, &unallocated);
102 }
103
match_release(const char * fn,struct expression * expr,void * _arg_no)104 static void match_release(const char *fn, struct expression *expr, void *_arg_no)
105 {
106 struct expression *arg_expr;
107 int arg_no = PTR_INT(_arg_no);
108
109 arg_expr = get_argument_from_call_expr(expr->args, arg_no);
110 if (get_state_expr(my_id, arg_expr))
111 set_state_expr(my_id, arg_expr, &unallocated);
112 set_equiv_state_expr(my_id, arg_expr, &unallocated);
113 }
114
match_unwind_function(const char * fn,struct expression * expr,void * unused)115 static void match_unwind_function(const char *fn, struct expression *expr, void *unused)
116 {
117 set_state(my_id, "unwind_function", NULL, &called);
118 }
119
func_returns_int(void)120 static int func_returns_int(void)
121 {
122 struct symbol *type;
123
124 type = get_base_type(cur_func_sym);
125 if (!type || type->type != SYM_FN)
126 return 0;
127 type = get_base_type(type);
128 if (type && type->ctype.base_type == &int_type) {
129 return 1;
130 }
131 return 0;
132 }
133
match_return(struct expression * ret_value)134 static void match_return(struct expression *ret_value)
135 {
136 struct stree *stree;
137 struct sm_state *tmp;
138 sval_t sval;
139
140 if (!func_returns_int())
141 return;
142 if (get_value(ret_value, &sval) && sval_cmp_val(sval, 0) >= 0)
143 return;
144 if (!implied_not_equal(ret_value, 0))
145 return;
146 if (get_state(my_id, "unwind_function", NULL) == &called)
147 return;
148
149 stree = __get_cur_stree();
150 FOR_EACH_MY_SM(my_id, stree, tmp) {
151 if (slist_has_state(tmp->possible, &allocated))
152 sm_warning("'%s' was not released on error", tmp->name);
153 } END_FOR_EACH_SM(tmp);
154 }
155
register_unwind_functions(void)156 static void register_unwind_functions(void)
157 {
158 struct token *token;
159 const char *func;
160
161 token = get_tokens_file("kernel.unwind_functions");
162 if (!token)
163 return;
164 if (token_type(token) != TOKEN_STREAMBEGIN)
165 return;
166 token = token->next;
167 while (token_type(token) != TOKEN_STREAMEND) {
168 if (token_type(token) != TOKEN_IDENT)
169 return;
170 func = show_ident(token->ident);
171 add_function_hook(func, &match_unwind_function, NULL);
172 token = token->next;
173 }
174 clear_token_alloc();
175 }
176
release_function_indicator(const char * name)177 static void release_function_indicator(const char *name)
178 {
179 if (!option_info)
180 return;
181 add_function_hook(name, &print_unwind_functions, INT_PTR(0));
182 }
183
check_unwind(int id)184 void check_unwind(int id)
185 {
186 if (option_project != PROJ_KERNEL || !option_spammy)
187 return;
188 my_id = id;
189
190 register_unwind_functions();
191
192 return_implies_state("request_resource", 0, 0, &request_granted, INT_PTR(1));
193 return_implies_state("request_resource", -EBUSY, -EBUSY, &request_denied, INT_PTR(1));
194 add_function_hook("release_resource", &match_release, INT_PTR(0));
195 release_function_indicator("release_resource");
196
197 return_implies_state_sval("__request_region", valid_ptr_min_sval, valid_ptr_max_sval, &request_granted, INT_PTR(1));
198 return_implies_state("__request_region", 0, 0, &request_denied, INT_PTR(1));
199 add_function_hook("__release_region", &match_release, INT_PTR(1));
200 release_function_indicator("__release_region");
201
202 return_implies_state_sval("ioremap", valid_ptr_min_sval, valid_ptr_max_sval, &request_granted, INT_PTR(-1));
203 return_implies_state("ioremap", 0, 0, &request_denied, INT_PTR(-1));
204 add_function_hook("iounmap", &match_release, INT_PTR(0));
205
206 return_implies_state_sval("pci_iomap", valid_ptr_min_sval, valid_ptr_max_sval, &request_granted, INT_PTR(-1));
207 return_implies_state("pci_iomap", 0, 0, &request_denied, INT_PTR(-1));
208 add_function_hook("pci_iounmap", &match_release, INT_PTR(1));
209 release_function_indicator("pci_iounmap");
210
211 return_implies_state_sval("__create_workqueue_key", valid_ptr_min_sval, valid_ptr_max_sval, &request_granted,
212 INT_PTR(-1));
213 return_implies_state("__create_workqueue_key", 0, 0, &request_denied, INT_PTR(-1));
214 add_function_hook("destroy_workqueue", &match_release, INT_PTR(0));
215
216 return_implies_state("request_irq", 0, 0, &request_granted, INT_PTR(0));
217 return_implies_state("request_irq", -MAX_ERRNO, -1, &request_denied, INT_PTR(0));
218 add_function_hook("free_irq", &match_release, INT_PTR(0));
219 release_function_indicator("free_irq");
220
221 return_implies_state("register_netdev", 0, 0, &request_granted, INT_PTR(0));
222 return_implies_state("register_netdev", -MAX_ERRNO, -1, &request_denied, INT_PTR(0));
223 add_function_hook("unregister_netdev", &match_release, INT_PTR(0));
224 release_function_indicator("unregister_netdev");
225
226 return_implies_state("misc_register", 0, 0, &request_granted, INT_PTR(0));
227 return_implies_state("misc_register", -MAX_ERRNO, -1, &request_denied, INT_PTR(0));
228 add_function_hook("misc_deregister", &match_release, INT_PTR(0));
229 release_function_indicator("misc_deregister");
230
231 add_hook(&match_return, RETURN_HOOK);
232 }
233