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_divrem_overflow(void)
 15{
 16	volatile int val = 16;
 17	volatile int val2 = 0;
 18
 19	UBSAN_TEST(CONFIG_UBSAN_DIV_ZERO);
 20	val /= val2;
 21}
 22
 23static void test_ubsan_shift_out_of_bounds(void)
 24{
 25	volatile int neg = -1, wrap = 4;
 26	int val1 = 10;
 27	int val2 = INT_MAX;
 28
 29	UBSAN_TEST(CONFIG_UBSAN_SHIFT, "negative exponent");
 30	val1 <<= neg;
 31
 32	UBSAN_TEST(CONFIG_UBSAN_SHIFT, "left overflow");
 33	val2 <<= wrap;
 34}
 35
 36static void test_ubsan_out_of_bounds(void)
 37{
 38	volatile int i = 4, j = 5, k = -1;
 39	volatile char above[4] = { }; /* Protect surrounding memory. */
 40	volatile int arr[4];
 41	volatile char below[4] = { }; /* Protect surrounding memory. */
 42
 43	above[0] = below[0];
 44
 45	UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "above");
 46	arr[j] = i;
 47
 48	UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "below");
 49	arr[k] = i;
 50}
 51
 52enum ubsan_test_enum {
 53	UBSAN_TEST_ZERO = 0,
 54	UBSAN_TEST_ONE,
 55	UBSAN_TEST_MAX,
 56};
 57
 58static void test_ubsan_load_invalid_value(void)
 59{
 60	volatile char *dst, *src;
 61	bool val, val2, *ptr;
 62	enum ubsan_test_enum eval, eval2, *eptr;
 63	unsigned char c = 0xff;
 64
 65	UBSAN_TEST(CONFIG_UBSAN_BOOL, "bool");
 66	dst = (char *)&val;
 67	src = &c;
 68	*dst = *src;
 69
 70	ptr = &val2;
 71	val2 = val;
 72
 73	UBSAN_TEST(CONFIG_UBSAN_ENUM, "enum");
 74	dst = (char *)&eval;
 75	src = &c;
 76	*dst = *src;
 77
 78	eptr = &eval2;
 79	eval2 = eval;
 80}
 81
 82static void test_ubsan_misaligned_access(void)
 83{
 84	volatile char arr[5] __aligned(4) = {1, 2, 3, 4, 5};
 85	volatile int *ptr, val = 6;
 86
 87	UBSAN_TEST(CONFIG_UBSAN_ALIGNMENT);
 88	ptr = (int *)(arr + 1);
 89	*ptr = val;
 90}
 91
 92static const test_ubsan_fp test_ubsan_array[] = {
 93	test_ubsan_shift_out_of_bounds,
 94	test_ubsan_out_of_bounds,
 95	test_ubsan_load_invalid_value,
 96	test_ubsan_misaligned_access,
 97};
 98
 99/* Excluded because they Oops the module. */
100static const test_ubsan_fp skip_ubsan_array[] = {
101	test_ubsan_divrem_overflow,
102};
103
104static int __init test_ubsan_init(void)
105{
106	unsigned int i;
107
108	for (i = 0; i < ARRAY_SIZE(test_ubsan_array); i++)
109		test_ubsan_array[i]();
110
111	return 0;
112}
113module_init(test_ubsan_init);
114
115static void __exit test_ubsan_exit(void)
116{
117	/* do nothing */
118}
119module_exit(test_ubsan_exit);
120
121MODULE_AUTHOR("Jinbum Park <jinb.park7@gmail.com>");
122MODULE_LICENSE("GPL v2");