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/test.h>
  19 #include <linux/device.h>
  20 #include <linux/slab.h>
  21 #include <linux/string.h>
  22 #include <linux/vmalloc.h>
  23
  24 static const char array_of_10[] = "this is 10";
  25 static const char *ptr_of_11 = "this is 11!";
  26 static char array_unknown[] = "compiler thinks I might change";
  27
  28 /* Handle being built without CONFIG_FORTIFY_SOURCE */
  29 #ifndef __compiletime_strlen
  30 # define __compiletime_strlen __builtin_strlen
  31 #endif
  32
  33 static void known_sizes_test(struct kunit *test)
  34 {
  35         KUNIT_EXPECT_EQ(test, __compiletime_strlen("88888888"), 8);
  36         KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_of_10), 10);
  37         KUNIT_EXPECT_EQ(test, __compiletime_strlen(ptr_of_11), 11);
  38
  39         KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_unknown), SIZE_MAX);
  40         /* Externally defined and dynamically sized string pointer: */
  41         KUNIT_EXPECT_EQ(test, __compiletime_strlen(test->name), SIZE_MAX);
  42 }
  43
  44 /* This is volatile so the optimizer can't perform DCE below. */
  45 static volatile int pick;
  46
  47 /* Not inline to keep optimizer from figuring out which string we want. */
  48 static noinline size_t want_minus_one(int pick)
  49 {
  50         const char *str;
  51
  52         switch (pick) {
  53         case 1:
  54                 str = "4444";
  55                 break;
  56         case 2:
  57                 str = "333";
  58                 break;
  59         default:
  60                 str = "1";
  61                 break;
  62         }
  63         return __compiletime_strlen(str);
  64 }
  65
  66 static void control_flow_split_test(struct kunit *test)
  67 {
  68         KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX);
  69 }
  70
  71 #define KUNIT_EXPECT_BOS(test, p, expected, name)                       \
  72         KUNIT_EXPECT_EQ_MSG(test, __builtin_object_size(p, 1),          \
  73                 expected,                                               \
  74                 "__alloc_size() not working with __bos on " name "\n")
  75
  76 #if !__has_builtin(__builtin_dynamic_object_size)
  77 #define KUNIT_EXPECT_BDOS(test, p, expected, name)                      \
  78         /* Silence "unused variable 'expected'" warning. */             \
  79         KUNIT_EXPECT_EQ(test, expected, expected)
  80 #else
  81 #define KUNIT_EXPECT_BDOS(test, p, expected, name)                      \
  82         KUNIT_EXPECT_EQ_MSG(test, __builtin_dynamic_object_size(p, 1),  \
  83                 expected,                                               \
  84                 "__alloc_size() not working with __bdos on " name "\n")
  85 #endif
  86
  87 /* If the execpted size is a constant value, __bos can see it. */
  88 #define check_const(_expected, alloc, free)             do {            \
  89         size_t expected = (_expected);                                  \
  90         void *p = alloc;                                                \
  91         KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n");   \
  92         KUNIT_EXPECT_BOS(test, p, expected, #alloc);                    \
  93         KUNIT_EXPECT_BDOS(test, p, expected, #alloc);                   \
  94         free;                                                           \
  95 } while (0)
  96
  97 /* If the execpted size is NOT a constant value, __bos CANNOT see it. */
  98 #define check_dynamic(_expected, alloc, free)           do {            \
  99         size_t expected = (_expected);                                  \
 100         void *p = alloc;                                                \
 101         KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n");   \
 102         KUNIT_EXPECT_BOS(test, p, SIZE_MAX, #alloc);                    \
 103         KUNIT_EXPECT_BDOS(test, p, expected, #alloc);                   \
 104         free;                                                           \
 105 } while (0)
 106
 107 /* Assortment of constant-value kinda-edge cases. */
 108 #define CONST_TEST_BODY(TEST_alloc)     do {                            \
 109         /* Special-case vmalloc()-family to skip 0-sized allocs. */     \
 110         if (strcmp(#TEST_alloc, "TEST_vmalloc") != 0)                   \
 111                 TEST_alloc(check_const, 0, 0);                          \
 112         TEST_alloc(check_const, 1, 1);                                  \
 113         TEST_alloc(check_const, 128, 128);                              \
 114         TEST_alloc(check_const, 1023, 1023);                            \
 115         TEST_alloc(check_const, 1025, 1025);                            \
 116         TEST_alloc(check_const, 4096, 4096);                            \
 117         TEST_alloc(check_const, 4097, 4097);                            \
 118 } while (0)
 119
 120 static volatile size_t zero_size;
 121 static volatile size_t unknown_size = 50;
 122
 123 #if !__has_builtin(__builtin_dynamic_object_size)
 124 #define DYNAMIC_TEST_BODY(TEST_alloc)                                   \
 125         kunit_skip(test, "Compiler is missing __builtin_dynamic_object_size() support\n")
 126 #else
 127 #define DYNAMIC_TEST_BODY(TEST_alloc)   do {                            \
 128         size_t size = unknown_size;                                     \
 129                                                                         \
 130         /*                                                              \
 131          * Expected size is "size" in each test, before it is then      \
 132          * internally incremented in each test. Requires we disable     \
 133          * -Wunsequenced.                                               \
 134          */                                                             \
 135         TEST_alloc(check_dynamic, size, size++);                        \
 136         /* Make sure incrementing actually happened. */                 \
 137         KUNIT_EXPECT_NE(test, size, unknown_size);                      \
 138 } while (0)
 139 #endif
 140
 141 #define DEFINE_ALLOC_SIZE_TEST_PAIR(allocator)                          \
 142 static void alloc_size_##allocator##_const_test(struct kunit *test)     \
 143 {                                                                       \
 144         CONST_TEST_BODY(TEST_##allocator);                              \
 145 }                                                                       \
 146 static void alloc_size_##allocator##_dynamic_test(struct kunit *test)   \
 147 {                                                                       \
 148         DYNAMIC_TEST_BODY(TEST_##allocator);                            \
 149 }
 150
 151 #define TEST_kmalloc(checker, expected_size, alloc_size)        do {    \
 152         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 153         void *orig;                                                     \
 154         size_t len;                                                     \
 155                                                                         \
 156         checker(expected_size, kmalloc(alloc_size, gfp),                \
 157                 kfree(p));                                              \
 158         checker(expected_size,                                          \
 159                 kmalloc_node(alloc_size, gfp, NUMA_NO_NODE),            \
 160                 kfree(p));                                              \
 161         checker(expected_size, kzalloc(alloc_size, gfp),                \
 162                 kfree(p));                                              \
 163         checker(expected_size,                                          \
 164                 kzalloc_node(alloc_size, gfp, NUMA_NO_NODE),            \
 165                 kfree(p));                                              \
 166         checker(expected_size, kcalloc(1, alloc_size, gfp),             \
 167                 kfree(p));                                              \
 168         checker(expected_size, kcalloc(alloc_size, 1, gfp),             \
 169                 kfree(p));                                              \
 170         checker(expected_size,                                          \
 171                 kcalloc_node(1, alloc_size, gfp, NUMA_NO_NODE),         \
 172                 kfree(p));                                              \
 173         checker(expected_size,                                          \
 174                 kcalloc_node(alloc_size, 1, gfp, NUMA_NO_NODE),         \
 175                 kfree(p));                                              \
 176         checker(expected_size, kmalloc_array(1, alloc_size, gfp),       \
 177                 kfree(p));                                              \
 178         checker(expected_size, kmalloc_array(alloc_size, 1, gfp),       \
 179                 kfree(p));                                              \
 180         checker(expected_size,                                          \
 181                 kmalloc_array_node(1, alloc_size, gfp, NUMA_NO_NODE),   \
 182                 kfree(p));                                              \
 183         checker(expected_size,                                          \
 184                 kmalloc_array_node(alloc_size, 1, gfp, NUMA_NO_NODE),   \
 185                 kfree(p));                                              \
 186         checker(expected_size, __kmalloc(alloc_size, gfp),              \
 187                 kfree(p));                                              \
 188         checker(expected_size,                                          \
 189                 __kmalloc_node(alloc_size, gfp, NUMA_NO_NODE),          \
 190                 kfree(p));                                              \
 191                                                                         \
 192         orig = kmalloc(alloc_size, gfp);                                \
 193         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 194         checker((expected_size) * 2,                                    \
 195                 krealloc(orig, (alloc_size) * 2, gfp),                  \
 196                 kfree(p));                                              \
 197         orig = kmalloc(alloc_size, gfp);                                \
 198         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 199         checker((expected_size) * 2,                                    \
 200                 krealloc_array(orig, 1, (alloc_size) * 2, gfp),         \
 201                 kfree(p));                                              \
 202         orig = kmalloc(alloc_size, gfp);                                \
 203         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 204         checker((expected_size) * 2,                                    \
 205                 krealloc_array(orig, (alloc_size) * 2, 1, gfp),         \
 206                 kfree(p));                                              \
 207                                                                         \
 208         len = 11;                                                       \
 209         /* Using memdup() with fixed size, so force unknown length. */  \
 210         if (!__builtin_constant_p(expected_size))                       \
 211                 len += zero_size;                                       \
 212         checker(len, kmemdup("hello there", len, gfp), kfree(p));       \
 213 } while (0)
 214 DEFINE_ALLOC_SIZE_TEST_PAIR(kmalloc)
 215
 216 /* Sizes are in pages, not bytes. */
 217 #define TEST_vmalloc(checker, expected_pages, alloc_pages)      do {    \
 218         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 219         checker((expected_pages) * PAGE_SIZE,                           \
 220                 vmalloc((alloc_pages) * PAGE_SIZE),        vfree(p));   \
 221         checker((expected_pages) * PAGE_SIZE,                           \
 222                 vzalloc((alloc_pages) * PAGE_SIZE),        vfree(p));   \
 223         checker((expected_pages) * PAGE_SIZE,                           \
 224                 __vmalloc((alloc_pages) * PAGE_SIZE, gfp), vfree(p));   \
 225 } while (0)
 226 DEFINE_ALLOC_SIZE_TEST_PAIR(vmalloc)
 227
 228 /* Sizes are in pages (and open-coded for side-effects), not bytes. */
 229 #define TEST_kvmalloc(checker, expected_pages, alloc_pages)     do {    \
 230         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 231         size_t prev_size;                                               \
 232         void *orig;                                                     \
 233                                                                         \
 234         checker((expected_pages) * PAGE_SIZE,                           \
 235                 kvmalloc((alloc_pages) * PAGE_SIZE, gfp),               \
 236                 vfree(p));                                              \
 237         checker((expected_pages) * PAGE_SIZE,                           \
 238                 kvmalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \
 239                 vfree(p));                                              \
 240         checker((expected_pages) * PAGE_SIZE,                           \
 241                 kvzalloc((alloc_pages) * PAGE_SIZE, gfp),               \
 242                 vfree(p));                                              \
 243         checker((expected_pages) * PAGE_SIZE,                           \
 244                 kvzalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \
 245                 vfree(p));                                              \
 246         checker((expected_pages) * PAGE_SIZE,                           \
 247                 kvcalloc(1, (alloc_pages) * PAGE_SIZE, gfp),            \
 248                 vfree(p));                                              \
 249         checker((expected_pages) * PAGE_SIZE,                           \
 250                 kvcalloc((alloc_pages) * PAGE_SIZE, 1, gfp),            \
 251                 vfree(p));                                              \
 252         checker((expected_pages) * PAGE_SIZE,                           \
 253                 kvmalloc_array(1, (alloc_pages) * PAGE_SIZE, gfp),      \
 254                 vfree(p));                                              \
 255         checker((expected_pages) * PAGE_SIZE,                           \
 256                 kvmalloc_array((alloc_pages) * PAGE_SIZE, 1, gfp),      \
 257                 vfree(p));                                              \
 258                                                                         \
 259         prev_size = (expected_pages) * PAGE_SIZE;                       \
 260         orig = kvmalloc(prev_size, gfp);                                \
 261         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 262         checker(((expected_pages) * PAGE_SIZE) * 2,                     \
 263                 kvrealloc(orig, prev_size,                              \
 264                           ((alloc_pages) * PAGE_SIZE) * 2, gfp),        \
 265                 kvfree(p));                                             \
 266 } while (0)
 267 DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc)
 268
 269 #define TEST_devm_kmalloc(checker, expected_size, alloc_size)   do {    \
 270         gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;                          \
 271         const char dev_name[] = "fortify-test";                         \
 272         struct device *dev;                                             \
 273         void *orig;                                                     \
 274         size_t len;                                                     \
 275                                                                         \
 276         /* Create dummy device for devm_kmalloc()-family tests. */      \
 277         dev = root_device_register(dev_name);                           \
 278         KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev),                       \
 279                                "Cannot register test device\n");        \
 280                                                                         \
 281         checker(expected_size, devm_kmalloc(dev, alloc_size, gfp),      \
 282                 devm_kfree(dev, p));                                    \
 283         checker(expected_size, devm_kzalloc(dev, alloc_size, gfp),      \
 284                 devm_kfree(dev, p));                                    \
 285         checker(expected_size,                                          \
 286                 devm_kmalloc_array(dev, 1, alloc_size, gfp),            \
 287                 devm_kfree(dev, p));                                    \
 288         checker(expected_size,                                          \
 289                 devm_kmalloc_array(dev, alloc_size, 1, gfp),            \
 290                 devm_kfree(dev, p));                                    \
 291         checker(expected_size,                                          \
 292                 devm_kcalloc(dev, 1, alloc_size, gfp),                  \
 293                 devm_kfree(dev, p));                                    \
 294         checker(expected_size,                                          \
 295                 devm_kcalloc(dev, alloc_size, 1, gfp),                  \
 296                 devm_kfree(dev, p));                                    \
 297                                                                         \
 298         orig = devm_kmalloc(dev, alloc_size, gfp);                      \
 299         KUNIT_EXPECT_TRUE(test, orig != NULL);                          \
 300         checker((expected_size) * 2,                                    \
 301                 devm_krealloc(dev, orig, (alloc_size) * 2, gfp),        \
 302                 devm_kfree(dev, p));                                    \
 303                                                                         \
 304         len = 4;                                                        \
 305         /* Using memdup() with fixed size, so force unknown length. */  \
 306         if (!__builtin_constant_p(expected_size))                       \
 307                 len += zero_size;                                       \
 308         checker(len, devm_kmemdup(dev, "Ohai", len, gfp),               \
 309                 devm_kfree(dev, p));                                    \
 310                                                                         \
 311         device_unregister(dev);                                         \
 312 } while (0)
 313 DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)
 314
 315 static int fortify_test_init(struct kunit *test)
 316 {
 317         if (!IS_ENABLED(CONFIG_FORTIFY_SOURCE))
 318                 kunit_skip(test, "Not built with CONFIG_FORTIFY_SOURCE=y");
 319
 320         return 0;
 321 }
 322
 323 static struct kunit_case fortify_test_cases[] = {
 324         KUNIT_CASE(known_sizes_test),
 325         KUNIT_CASE(control_flow_split_test),
 326         KUNIT_CASE(alloc_size_kmalloc_const_test),
 327         KUNIT_CASE(alloc_size_kmalloc_dynamic_test),
 328         KUNIT_CASE(alloc_size_vmalloc_const_test),
 329         KUNIT_CASE(alloc_size_vmalloc_dynamic_test),
 330         KUNIT_CASE(alloc_size_kvmalloc_const_test),
 331         KUNIT_CASE(alloc_size_kvmalloc_dynamic_test),
 332         KUNIT_CASE(alloc_size_devm_kmalloc_const_test),
 333         KUNIT_CASE(alloc_size_devm_kmalloc_dynamic_test),
 334         {}
 335 };
 336
 337 static struct kunit_suite fortify_test_suite = {
 338         .name = "fortify",
 339         .init = fortify_test_init,
 340         .test_cases = fortify_test_cases,
 341 };
 342
 343 kunit_test_suite(fortify_test_suite);
 344
 345 MODULE_LICENSE("GPL");