lib/fortify_kunit.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Runtime test cases for CONFIG_FORTIFY_SOURCE that aren't expected to
   4  * Oops the kernel on success. (For those, see drivers/misc/lkdtm/fortify.c)
   5  *
   6  * For corner cases with UBSAN, try testing with:
   7  *
   8  * ./tools/testing/kunit/kunit.py run --arch=x86_64 \
   9  *      --kconfig_add CONFIG_FORTIFY_SOURCE=y \
  10  *      --kconfig_add CONFIG_UBSAN=y \
  11  *      --kconfig_add CONFIG_UBSAN_TRAP=y \
  12  *      --kconfig_add CONFIG_UBSAN_BOUNDS=y \
  13  *      --kconfig_add CONFIG_UBSAN_LOCAL_BOUNDS=y \
  14  *      --make_options LLVM=1 fortify
  15  */
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <kunit/device.h>
  19 #include <kunit/test.h>
  20 #include <linux/device.h>
  21 #include <linux/slab.h>
  22 #include <linux/string.h>
  23 #include <linux/vmalloc.h>
  24
  25 static const char array_of_10[] = "this is 10";
  26 static const char *ptr_of_11 = "this is 11!";
  27 static char array_unknown[] = "compiler thinks I might change";
  28
  29 static void known_sizes_test(struct kunit *test)
  30 {
  31         KUNIT_EXPECT_EQ(test, __compiletime_strlen("88888888"), 8);
  32         KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_of_10), 10);
  33         KUNIT_EXPECT_EQ(test, __compiletime_strlen(ptr_of_11), 11);
  34
  35         KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_unknown), SIZE_MAX);
  36         /* Externally defined and dynamically sized string pointer: */
  37         KUNIT_EXPECT_EQ(test, __compiletime_strlen(test->name), SIZE_MAX);
  38 }
  39
  40 /* This is volatile so the optimizer can't perform DCE below. */
  41 static volatile int pick;
  42
  43 /* Not inline to keep optimizer from figuring out which string we want. */
  44 static noinline size_t want_minus_one(int pick)
  45 {
  46         const char *str;
  47
  48         switch (pick) {
  49         case 1:
  50                 str = "4444";
  51                 break;
  52         case 2:
  53                 str = "333";
  54                 break;
  55         default:
  56                 str = "1";
  57                 break;
  58         }
  59         return __compiletime_strlen(str);
  60 }
  61
  62 static void control_flow_split_test(struct kunit *test)
  63 {
  64         KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX);
  65 }
  66
  67 #define KUNIT_EXPECT_BOS(test, p, expected, name)                       \
  68         KUNIT_EXPECT_EQ_MSG(test, __builtin_object_size(p, 1),          \
  69                 expected,                                               \
  70                 "__alloc_size() not working with __bos on " name "\n")
  71
  72 #if !__has_builtin(__builtin_dynamic_object_size)
  73 #define KUNIT_EXPECT_BDOS(test, p, expected, name)                      \
  74         /* Silence "unused variable 'expected'" warning. */             \
  75         KUNIT_EXPECT_EQ(test, expected, expected)
  76 #else
  77 #define KUNIT_EXPECT_BDOS(test, p, expected, name)                      \
  78         KUNIT_EXPECT_EQ_MSG(test, __builtin_dynamic_object_size(p, 1),  \
  79                 expected,                                               \
  80                 "__alloc_size() not working with __bdos on " name "\n")
  81 #endif
  82
  83 /* If the execpted size is a constant value, __bos can see it. */
  84 #define check_const(_expected, alloc, free)             do {            \
  85         size_t expected = (_expected);                                  \
  86         void *p = alloc;                                                \
  87         KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n");   \
  88         KUNIT_EXPECT_BOS(test, p, expected, #alloc);                    \
  89         KUNIT_EXPECT_BDOS(test, p, expected, #alloc);                   \
  90         free;                                                           \
  91 } while (0)
  92
  93 /* If the execpted size is NOT a constant value, __bos CANNOT see it. */
  94 #define check_dynamic(_expected, alloc, free)           do {            \
  95         size_t expected = (_expected);                                  \
  96         void *p = alloc;                                                \
  97         KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n");   \
  98         KUNIT_EXPECT_BOS(test, p, SIZE_MAX, #alloc);                    \
  99         KUNIT_EXPECT_BDOS(test, p, expected, #alloc);                   \
 100         free;                                                           \
 101 } while (0)
 102
 103 /* Assortment of constant-value kinda-edge cases. */
 104 #define CONST_TEST_BODY(TEST_alloc)     do {                            \
 105         /* Special-case vmalloc()-family to skip 0-sized allocs. */     \
 106         if (strcmp(#TEST_alloc, "TEST_vmalloc") != 0)                   \
 107                 TEST_alloc(check_const, 0, 0);                          \
 108         TEST_alloc(check_const, 1, 1);                                  \
 109         TEST_alloc(check_const, 128, 128);                              \
 110         TEST_alloc(check_const, 1023, 1023);                            \
 111         TEST_alloc(check_const, 1025, 1025);                            \
 112         TEST_alloc(check_const, 4096, 4096);                            \
 113         TEST_alloc(check_const, 4097, 4097);                            \
 114 } while (0)
 115
 116 static volatile size_t zero_size;
 117 static volatile size_t unknown_size = 50;
 118
 119 #if !__has_builtin(__builtin_dynamic_object_size)
 120 #define DYNAMIC_TEST_BODY(TEST_alloc)                                   \
 121         kunit_skip(test, "Compiler is missing __builtin_dynamic_object_size() support\n")
 122 #else
 123 #define DYNAMIC_TEST_BODY(TEST_alloc)   do {                            \
 124         size_t size = unknown_size;                                     \
 125                                                                         \
 126         /*                                                              \
 127          * Expected size is "size" in each test, before it is then      \
 128          * internally incremented in each test. Requires we disable     \
 129          * -Wunsequenced.                                               \
 130          */                                                             \
 131         TEST_alloc(check_dynamic, size, size++);                        \
 132         /* Make sure incrementing actually happened. */                 \
 133         KUNIT_EXPECT_NE(test, size, unknown_size);                      \
 134 } while (0)
 135 #endif
 136
 137 #define DEFINE_ALLOC_SIZE_TEST_PAIR(allocator)                          \
 138 static void alloc_size_##allocator##_const_test(struct kunit *test)     \
 139 {                                                                       \
 140         CONST_TEST_BODY(TEST_##allocator);                              \
 141 }                                                                       \
 142 static void alloc_size_##allocator##_dynamic_test(struct kunit *test)   \
 143 {                                                                       \
 144         DYNAMIC_TEST_BODY(TEST_##allocator);                            \
 145 }
 146
 147 #define TEST_kmalloc(checker, expected_size, alloc_size)        do {    \
 148         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 149         void *orig;                                                     \
 150         size_t len;                                                     \
 151                                                                         \
 152         checker(expected_size, kmalloc(alloc_size, gfp),                \
 153                 kfree(p));                                              \
 154         checker(expected_size,                                          \
 155                 kmalloc_node(alloc_size, gfp, NUMA_NO_NODE),            \
 156                 kfree(p));                                              \
 157         checker(expected_size, kzalloc(alloc_size, gfp),                \
 158                 kfree(p));                                              \
 159         checker(expected_size,                                          \
 160                 kzalloc_node(alloc_size, gfp, NUMA_NO_NODE),            \
 161                 kfree(p));                                              \
 162         checker(expected_size, kcalloc(1, alloc_size, gfp),             \
 163                 kfree(p));                                              \
 164         checker(expected_size, kcalloc(alloc_size, 1, gfp),             \
 165                 kfree(p));                                              \
 166         checker(expected_size,                                          \
 167                 kcalloc_node(1, alloc_size, gfp, NUMA_NO_NODE),         \
 168                 kfree(p));                                              \
 169         checker(expected_size,                                          \
 170                 kcalloc_node(alloc_size, 1, gfp, NUMA_NO_NODE),         \
 171                 kfree(p));                                              \
 172         checker(expected_size, kmalloc_array(1, alloc_size, gfp),       \
 173                 kfree(p));                                              \
 174         checker(expected_size, kmalloc_array(alloc_size, 1, gfp),       \
 175                 kfree(p));                                              \
 176         checker(expected_size,                                          \
 177                 kmalloc_array_node(1, alloc_size, gfp, NUMA_NO_NODE),   \
 178                 kfree(p));                                              \
 179         checker(expected_size,                                          \
 180                 kmalloc_array_node(alloc_size, 1, gfp, NUMA_NO_NODE),   \
 181                 kfree(p));                                              \
 182         checker(expected_size, __kmalloc(alloc_size, gfp),              \
 183                 kfree(p));                                              \
 184         checker(expected_size,                                          \
 185                 __kmalloc_node(alloc_size, gfp, NUMA_NO_NODE),          \
 186                 kfree(p));                                              \
 187                                                                         \
 188         orig = kmalloc(alloc_size, gfp);                                \
 189         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 190         checker((expected_size) * 2,                                    \
 191                 krealloc(orig, (alloc_size) * 2, gfp),                  \
 192                 kfree(p));                                              \
 193         orig = kmalloc(alloc_size, gfp);                                \
 194         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 195         checker((expected_size) * 2,                                    \
 196                 krealloc_array(orig, 1, (alloc_size) * 2, gfp),         \
 197                 kfree(p));                                              \
 198         orig = kmalloc(alloc_size, gfp);                                \
 199         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 200         checker((expected_size) * 2,                                    \
 201                 krealloc_array(orig, (alloc_size) * 2, 1, gfp),         \
 202                 kfree(p));                                              \
 203                                                                         \
 204         len = 11;                                                       \
 205         /* Using memdup() with fixed size, so force unknown length. */  \
 206         if (!__builtin_constant_p(expected_size))                       \
 207                 len += zero_size;                                       \
 208         checker(len, kmemdup("hello there", len, gfp), kfree(p));       \
 209 } while (0)
 210 DEFINE_ALLOC_SIZE_TEST_PAIR(kmalloc)
 211
 212 /* Sizes are in pages, not bytes. */
 213 #define TEST_vmalloc(checker, expected_pages, alloc_pages)      do {    \
 214         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 215         checker((expected_pages) * PAGE_SIZE,                           \
 216                 vmalloc((alloc_pages) * PAGE_SIZE),        vfree(p));   \
 217         checker((expected_pages) * PAGE_SIZE,                           \
 218                 vzalloc((alloc_pages) * PAGE_SIZE),        vfree(p));   \
 219         checker((expected_pages) * PAGE_SIZE,                           \
 220                 __vmalloc((alloc_pages) * PAGE_SIZE, gfp), vfree(p));   \
 221 } while (0)
 222 DEFINE_ALLOC_SIZE_TEST_PAIR(vmalloc)
 223
 224 /* Sizes are in pages (and open-coded for side-effects), not bytes. */
 225 #define TEST_kvmalloc(checker, expected_pages, alloc_pages)     do {    \
 226         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 227         size_t prev_size;                                               \
 228         void *orig;                                                     \
 229                                                                         \
 230         checker((expected_pages) * PAGE_SIZE,                           \
 231                 kvmalloc((alloc_pages) * PAGE_SIZE, gfp),               \
 232                 vfree(p));                                              \
 233         checker((expected_pages) * PAGE_SIZE,                           \
 234                 kvmalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \
 235                 vfree(p));                                              \
 236         checker((expected_pages) * PAGE_SIZE,                           \
 237                 kvzalloc((alloc_pages) * PAGE_SIZE, gfp),               \
 238                 vfree(p));                                              \
 239         checker((expected_pages) * PAGE_SIZE,                           \
 240                 kvzalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \
 241                 vfree(p));                                              \
 242         checker((expected_pages) * PAGE_SIZE,                           \
 243                 kvcalloc(1, (alloc_pages) * PAGE_SIZE, gfp),            \
 244                 vfree(p));                                              \
 245         checker((expected_pages) * PAGE_SIZE,                           \
 246                 kvcalloc((alloc_pages) * PAGE_SIZE, 1, gfp),            \
 247                 vfree(p));                                              \
 248         checker((expected_pages) * PAGE_SIZE,                           \
 249                 kvmalloc_array(1, (alloc_pages) * PAGE_SIZE, gfp),      \
 250                 vfree(p));                                              \
 251         checker((expected_pages) * PAGE_SIZE,                           \
 252                 kvmalloc_array((alloc_pages) * PAGE_SIZE, 1, gfp),      \
 253                 vfree(p));                                              \
 254                                                                         \
 255         prev_size = (expected_pages) * PAGE_SIZE;                       \
 256         orig = kvmalloc(prev_size, gfp);                                \
 257         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 258         checker(((expected_pages) * PAGE_SIZE) * 2,                     \
 259                 kvrealloc(orig, prev_size,                              \
 260                           ((alloc_pages) * PAGE_SIZE) * 2, gfp),        \
 261                 kvfree(p));                                             \
 262 } while (0)
 263 DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc)
 264
 265 #define TEST_devm_kmalloc(checker, expected_size, alloc_size)   do {    \
 266         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 267         const char dev_name[] = "fortify-test";                         \
 268         struct device *dev;                                             \
 269         void *orig;                                                     \
 270         size_t len;                                                     \
 271                                                                         \
 272         /* Create dummy device for devm_kmalloc()-family tests. */      \
 273         dev = kunit_device_register(test, dev_name);                    \
 274         KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),                       \
 275                                "Cannot register test device\n");        \
 276                                                                         \
 277         checker(expected_size, devm_kmalloc(dev, alloc_size, gfp),      \
 278                 devm_kfree(dev, p));                                    \
 279         checker(expected_size, devm_kzalloc(dev, alloc_size, gfp),      \
 280                 devm_kfree(dev, p));                                    \
 281         checker(expected_size,                                          \
 282                 devm_kmalloc_array(dev, 1, alloc_size, gfp),            \
 283                 devm_kfree(dev, p));                                    \
 284         checker(expected_size,                                          \
 285                 devm_kmalloc_array(dev, alloc_size, 1, gfp),            \
 286                 devm_kfree(dev, p));                                    \
 287         checker(expected_size,                                          \
 288                 devm_kcalloc(dev, 1, alloc_size, gfp),                  \
 289                 devm_kfree(dev, p));                                    \
 290         checker(expected_size,                                          \
 291                 devm_kcalloc(dev, alloc_size, 1, gfp),                  \
 292                 devm_kfree(dev, p));                                    \
 293                                                                         \
 294         orig = devm_kmalloc(dev, alloc_size, gfp);                      \
 295         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 296         checker((expected_size) * 2,                                    \
 297                 devm_krealloc(dev, orig, (alloc_size) * 2, gfp),        \
 298                 devm_kfree(dev, p));                                    \
 299                                                                         \
 300         len = 4;                                                        \
 301         /* Using memdup() with fixed size, so force unknown length. */  \
 302         if (!__builtin_constant_p(expected_size))                       \
 303                 len += zero_size;                                       \
 304         checker(len, devm_kmemdup(dev, "Ohai", len, gfp),               \
 305                 devm_kfree(dev, p));                                    \
 306                                                                         \
 307         kunit_device_unregister(test, dev);                             \
 308 } while (0)
 309 DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
 310
 311 static struct kunit_case fortify_test_cases[] = {
 312         KUNIT_CASE(known_sizes_test),
 313         KUNIT_CASE(control_flow_split_test),
 314         KUNIT_CASE(alloc_size_kmalloc_const_test),
 315         KUNIT_CASE(alloc_size_kmalloc_dynamic_test),
 316         KUNIT_CASE(alloc_size_vmalloc_const_test),
 317         KUNIT_CASE(alloc_size_vmalloc_dynamic_test),
 318         KUNIT_CASE(alloc_size_kvmalloc_const_test),
 319         KUNIT_CASE(alloc_size_kvmalloc_dynamic_test),
 320         KUNIT_CASE(alloc_size_devm_kmalloc_const_test),
 321         KUNIT_CASE(alloc_size_devm_kmalloc_dynamic_test),
 322         {}
 323 };
 324
 325 static struct kunit_suite fortify_test_suite = {
 326         .name = "fortify",
 327         .test_cases = fortify_test_cases,
 328 };
 329
 330 kunit_test_suite(fortify_test_suite);
 331
 332 MODULE_LICENSE("GPL");