1// SPDX-License-Identifier: GPL-2.0
2#include <linux/init.h>
3#include <linux/kernel.h>
4#include <linux/module.h>
5
6typedef void(*test_ubsan_fp)(void);
7
8#define UBSAN_TEST(config, ...)	do {					\
9		pr_info("%s " __VA_ARGS__ "%s(%s=%s)\n", __func__,	\
10			sizeof(" " __VA_ARGS__) > 2 ? " " : "",		\
11			#config, IS_ENABLED(config) ? "y" : "n");	\
12	} while (0)
13
14static void test_ubsan_add_overflow(void)
15{
16	volatile int val = INT_MAX;
17
18	UBSAN_TEST(CONFIG_UBSAN_SIGNED_WRAP);
19	val += 2;
20}
21
22static void test_ubsan_sub_overflow(void)
23{
24	volatile int val = INT_MIN;
25	volatile int val2 = 2;
26
27	UBSAN_TEST(CONFIG_UBSAN_SIGNED_WRAP);
28	val -= val2;
29}
30
31static void test_ubsan_mul_overflow(void)
32{
33	volatile int val = INT_MAX / 2;
34
35	UBSAN_TEST(CONFIG_UBSAN_SIGNED_WRAP);
36	val *= 3;
37}
38
39static void test_ubsan_negate_overflow(void)
40{
41	volatile int val = INT_MIN;
42
43	UBSAN_TEST(CONFIG_UBSAN_SIGNED_WRAP);
44	val = -val;
45}
46
47static void test_ubsan_divrem_overflow(void)
48{
49	volatile int val = 16;
50	volatile int val2 = 0;
51
52	UBSAN_TEST(CONFIG_UBSAN_DIV_ZERO);
53	val /= val2;
54}
55
56static void test_ubsan_shift_out_of_bounds(void)
57{
58	volatile int neg = -1, wrap = 4;
59	volatile int val1 = 10;
60	volatile int val2 = INT_MAX;
61
62	UBSAN_TEST(CONFIG_UBSAN_SHIFT, "negative exponent");
63	val1 <<= neg;
64
65	UBSAN_TEST(CONFIG_UBSAN_SHIFT, "left overflow");
66	val2 <<= wrap;
67}
68
69static void test_ubsan_out_of_bounds(void)
70{
71	volatile int i = 4, j = 5, k = -1;
72	volatile char above[4] = { }; /* Protect surrounding memory. */
73	volatile int arr[4];
74	volatile char below[4] = { }; /* Protect surrounding memory. */
75
76	above[0] = below[0];
77
78	UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "above");
79	arr[j] = i;
80
81	UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "below");
82	arr[k] = i;
83}
84
85enum ubsan_test_enum {
86	UBSAN_TEST_ZERO = 0,
87	UBSAN_TEST_ONE,
88	UBSAN_TEST_MAX,
89};
90
91static void test_ubsan_load_invalid_value(void)
92{
93	volatile char *dst, *src;
94	bool val, val2, *ptr;
95	enum ubsan_test_enum eval, eval2, *eptr;
96	unsigned char c = 0xff;
97
98	UBSAN_TEST(CONFIG_UBSAN_BOOL, "bool");
99	dst = (char *)&val;
100	src = &c;
101	*dst = *src;
102
103	ptr = &val2;
104	val2 = val;
105
106	UBSAN_TEST(CONFIG_UBSAN_ENUM, "enum");
107	dst = (char *)&eval;
108	src = &c;
109	*dst = *src;
110
111	eptr = &eval2;
112	eval2 = eval;
113}
114
115static void test_ubsan_misaligned_access(void)
116{
117	volatile char arr[5] __aligned(4) = {1, 2, 3, 4, 5};
118	volatile int *ptr, val = 6;
119
120	UBSAN_TEST(CONFIG_UBSAN_ALIGNMENT);
121	ptr = (int *)(arr + 1);
122	*ptr = val;
123}
124
125static const test_ubsan_fp test_ubsan_array[] = {
126	test_ubsan_add_overflow,
127	test_ubsan_sub_overflow,
128	test_ubsan_mul_overflow,
129	test_ubsan_negate_overflow,
130	test_ubsan_shift_out_of_bounds,
131	test_ubsan_out_of_bounds,
132	test_ubsan_load_invalid_value,
133	test_ubsan_misaligned_access,
134};
135
136/* Excluded because they Oops the module. */
137static __used const test_ubsan_fp skip_ubsan_array[] = {
138	test_ubsan_divrem_overflow,
139};
140
141static int __init test_ubsan_init(void)
142{
143	unsigned int i;
144
145	for (i = 0; i < ARRAY_SIZE(test_ubsan_array); i++)
146		test_ubsan_array[i]();
147
148	return 0;
149}
150module_init(test_ubsan_init);
151
152static void __exit test_ubsan_exit(void)
153{
154	/* do nothing */
155}
156module_exit(test_ubsan_exit);
157
158MODULE_AUTHOR("Jinbum Park <jinb.park7@gmail.com>");
159MODULE_LICENSE("GPL v2");
160