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#include "smatch.h"
19#include "smatch_slist.h"
20
21static int my_id;
22
23STATE(alloced);
24STATE(string);
25
26static char *my_get_variable(struct expression *expr, struct symbol **sym)
27{
28	char *name;
29
30	name = expr_to_var_sym(expr, sym);
31	free_string(name);
32	if (!name || !*sym)
33		return NULL;
34
35	return (*sym)->ident->name;
36}
37
38static void match_kmalloc(const char *fn, struct expression *expr, void *unused)
39{
40	char *name;
41	struct symbol *sym;
42
43	name = my_get_variable(expr->left, &sym);
44	if (!name)
45		return;
46	set_state(my_id, name, sym, &alloced);
47}
48
49static void match_strcpy(const char *fn, struct expression *expr, void *unused)
50{
51	struct expression *dest;
52	char *name;
53	struct symbol *sym;
54
55	dest = get_argument_from_call_expr(expr->args, 0);
56	name = my_get_variable(dest, &sym);
57	if (!name || !sym)
58		return;
59	if (!get_state(my_id, name, sym))
60		return;
61	set_state(my_id, name, sym, &string);
62}
63
64static void match_copy_to_user(const char *fn, struct expression *expr, void *unused)
65{
66	struct expression *src;
67	char *name;
68	struct symbol *sym;
69	struct sm_state *sm;
70
71	src = get_argument_from_call_expr(expr->args, 1);
72	name = my_get_variable(src, &sym);
73	if (!name || !sym)
74		return;
75	sm = get_sm_state(my_id, name, sym);
76	if (!sm || !slist_has_state(sm->possible, &string))
77		return;
78	name = expr_to_var(src);
79	sm_warning("possible info leak '%s'", name);
80	free_string(name);
81}
82
83void check_info_leak(int id)
84{
85	if (option_project != PROJ_KERNEL)
86		return;
87	my_id = id;
88	add_function_assign_hook("kmalloc", &match_kmalloc, NULL);
89	add_function_hook("strcpy", &match_strcpy, NULL);
90	add_function_hook("strlcpy", &match_strcpy, NULL);
91	add_function_hook("strlcat", &match_strcpy, NULL);
92	add_function_hook("strncpy", &match_strcpy, NULL);
93	add_function_hook("copy_to_user", &match_copy_to_user, NULL);
94}
95