lib/test_ubsan.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/init.h>
   3 #include <linux/kernel.h>
   4 #include <linux/module.h>
   5
   6 typedef 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
  14 static 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
  23 static 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
  36 static 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
  52 enum ubsan_test_enum {
  53         UBSAN_TEST_ZERO = 0,
  54         UBSAN_TEST_ONE,
  55         UBSAN_TEST_MAX,
  56 };
  57
  58 static 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
  82 static 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
  92 static 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. */
 100 static const test_ubsan_fp skip_ubsan_array[] = {
 101         test_ubsan_divrem_overflow,
 102 };
 103
 104 static 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 }
 113 module_init(test_ubsan_init);
 114
 115 static void __exit test_ubsan_exit(void)
 116 {
 117         /* do nothing */
 118 }
 119 module_exit(test_ubsan_exit);
 120
 121 MODULE_AUTHOR("Jinbum Park <jinb.park7@gmail.com>");
 122 MODULE_LICENSE("GPL v2");