1 /*
2 * Copyright (C) 2011 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 #include "smatch.h"
19
20 static int my_id;
21
get_data_size(struct expression * ptr)22 static int get_data_size(struct expression *ptr)
23 {
24 struct symbol *type;
25
26 type = get_type(ptr);
27 if (!type || type->type != SYM_PTR)
28 return 0;
29 type = get_base_type(type);
30 if (!type)
31 return 0;
32 return type_bytes(type);
33 }
34
check_size_matches(int data_size,struct expression * size_expr)35 static void check_size_matches(int data_size, struct expression *size_expr)
36 {
37 sval_t sval;
38
39 if (data_size == 1) /* this is generic a buffer */
40 return;
41
42 if (!get_implied_value(size_expr, &sval))
43 return;
44 if (sval_cmp_val(sval, data_size) != 0)
45 sm_warning("double check that we're allocating correct size: %d vs %s", data_size, sval_to_str(sval));
46 }
47
match_alloc(const char * fn,struct expression * expr,void * unused)48 static void match_alloc(const char *fn, struct expression *expr, void *unused)
49 {
50 struct expression *call = strip_expr(expr->right);
51 struct expression *arg;
52 int ptr_size;
53
54 ptr_size = get_data_size(expr->left);
55 if (!ptr_size)
56 return;
57
58 arg = get_argument_from_call_expr(call->args, 0);
59 arg = strip_expr(arg);
60 if (!arg || arg->type != EXPR_BINOP || arg->op != '*')
61 return;
62 if (expr->left->type == EXPR_SIZEOF)
63 check_size_matches(ptr_size, arg->left);
64 if (expr->right->type == EXPR_SIZEOF)
65 check_size_matches(ptr_size, arg->right);
66 }
67
match_calloc(const char * fn,struct expression * expr,void * _arg_nr)68 static void match_calloc(const char *fn, struct expression *expr, void *_arg_nr)
69 {
70 int arg_nr = PTR_INT(_arg_nr);
71 struct expression *call = strip_expr(expr->right);
72 struct expression *arg;
73 int ptr_size;
74
75 ptr_size = get_data_size(expr->left);
76 if (!ptr_size)
77 return;
78
79 arg = get_argument_from_call_expr(call->args, arg_nr);
80 check_size_matches(ptr_size, arg);
81 }
82
check_kmalloc_wrong_size(int id)83 void check_kmalloc_wrong_size(int id)
84 {
85 my_id = id;
86
87 if (option_project != PROJ_KERNEL) {
88 add_function_assign_hook("malloc", &match_alloc, NULL);
89 add_function_assign_hook("calloc", &match_calloc, INT_PTR(1));
90 return;
91 }
92
93 add_function_assign_hook("kmalloc", &match_alloc, NULL);
94 add_function_assign_hook("kcalloc", &match_calloc, INT_PTR(1));
95 }
96