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