1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Runtime test cases for CONFIG_FORTIFY_SOURCE. For additional memcpy() 4 * testing see FORTIFY_MEM_* tests in LKDTM (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 /* We don't need to fill dmesg with the fortify WARNs during testing. */ 19 #ifdef DEBUG 20 # define FORTIFY_REPORT_KUNIT(x...) __fortify_report(x) 21 # define FORTIFY_WARN_KUNIT(x...) WARN_ONCE(x) 22 #else 23 # define FORTIFY_REPORT_KUNIT(x...) do { } while (0) 24 # define FORTIFY_WARN_KUNIT(x...) do { } while (0) 25 #endif 26 27 /* Redefine fortify_panic() to track failures. */ 28 void fortify_add_kunit_error(int write); 29 #define fortify_panic(func, write, avail, size, retfail) do { \ 30 FORTIFY_REPORT_KUNIT(FORTIFY_REASON(func, write), avail, size); \ 31 fortify_add_kunit_error(write); \ 32 return (retfail); \ 33 } while (0) 34 35 /* Redefine fortify_warn_once() to track memcpy() failures. */ 36 #define fortify_warn_once(chk_func, x...) do { \ 37 bool __result = chk_func; \ 38 FORTIFY_WARN_KUNIT(__result, x); \ 39 if (__result) \ 40 fortify_add_kunit_error(1); \ 41 } while (0) 42 43 #include <kunit/device.h> 44 #include <kunit/test.h> 45 #include <kunit/test-bug.h> 46 #include <linux/device.h> 47 #include <linux/slab.h> 48 #include <linux/string.h> 49 #include <linux/vmalloc.h> 50 51 /* Handle being built without CONFIG_FORTIFY_SOURCE */ 52 #ifndef __compiletime_strlen 53 # define __compiletime_strlen __builtin_strlen 54 #endif 55 56 static struct kunit_resource read_resource; 57 static struct kunit_resource write_resource; 58 static int fortify_read_overflows; 59 static int fortify_write_overflows; 60 61 static const char array_of_10[] = "this is 10"; 62 static const char *ptr_of_11 = "this is 11!"; 63 static const char * const unchanging_12 = "this is 12!!"; 64 static char array_unknown[] = "compiler thinks I might change"; 65 66 void fortify_add_kunit_error(int write) 67 { 68 struct kunit_resource *resource; 69 struct kunit *current_test; 70 71 current_test = kunit_get_current_test(); 72 if (!current_test) 73 return; 74 75 resource = kunit_find_named_resource(current_test, 76 write ? "fortify_write_overflows" 77 : "fortify_read_overflows"); 78 if (!resource) 79 return; 80 81 (*(int *)resource->data)++; 82 kunit_put_resource(resource); 83 } 84 85 static void fortify_test_known_sizes(struct kunit *test) 86 { 87 char stack[80] = "Test!"; 88 89 KUNIT_EXPECT_FALSE(test, __is_constexpr(__builtin_strlen(stack))); 90 KUNIT_EXPECT_EQ(test, __compiletime_strlen(stack), 5); 91 92 KUNIT_EXPECT_TRUE(test, __is_constexpr(__builtin_strlen("88888888"))); 93 KUNIT_EXPECT_EQ(test, __compiletime_strlen("88888888"), 8); 94 95 KUNIT_EXPECT_TRUE(test, __is_constexpr(__builtin_strlen(array_of_10))); 96 KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_of_10), 10); 97 98 KUNIT_EXPECT_FALSE(test, __is_constexpr(__builtin_strlen(ptr_of_11))); 99 KUNIT_EXPECT_EQ(test, __compiletime_strlen(ptr_of_11), 11); 100 101 KUNIT_EXPECT_TRUE(test, __is_constexpr(__builtin_strlen(unchanging_12))); 102 KUNIT_EXPECT_EQ(test, __compiletime_strlen(unchanging_12), 12); 103 104 KUNIT_EXPECT_FALSE(test, __is_constexpr(__builtin_strlen(array_unknown))); 105 KUNIT_EXPECT_EQ(test, __compiletime_strlen(array_unknown), SIZE_MAX); 106 107 /* Externally defined and dynamically sized string pointer: */ 108 KUNIT_EXPECT_FALSE(test, __is_constexpr(__builtin_strlen(test->name))); 109 KUNIT_EXPECT_EQ(test, __compiletime_strlen(test->name), SIZE_MAX); 110 } 111 112 /* This is volatile so the optimizer can't perform DCE below. */ 113 static volatile int pick; 114 115 /* Not inline to keep optimizer from figuring out which string we want. */ 116 static noinline size_t want_minus_one(int pick) 117 { 118 const char *str; 119 120 switch (pick) { 121 case 1: 122 str = "4444"; 123 break; 124 case 2: 125 str = "333"; 126 break; 127 default: 128 str = "1"; 129 break; 130 } 131 return __compiletime_strlen(str); 132 } 133 134 static void fortify_test_control_flow_split(struct kunit *test) 135 { 136 KUNIT_EXPECT_EQ(test, want_minus_one(pick), SIZE_MAX); 137 } 138 139 #define KUNIT_EXPECT_BOS(test, p, expected, name) \ 140 KUNIT_EXPECT_EQ_MSG(test, __builtin_object_size(p, 1), \ 141 expected, \ 142 "__alloc_size() not working with __bos on " name "\n") 143 144 #if !__has_builtin(__builtin_dynamic_object_size) 145 #define KUNIT_EXPECT_BDOS(test, p, expected, name) \ 146 /* Silence "unused variable 'expected'" warning. */ \ 147 KUNIT_EXPECT_EQ(test, expected, expected) 148 #else 149 #define KUNIT_EXPECT_BDOS(test, p, expected, name) \ 150 KUNIT_EXPECT_EQ_MSG(test, __builtin_dynamic_object_size(p, 1), \ 151 expected, \ 152 "__alloc_size() not working with __bdos on " name "\n") 153 #endif 154 155 /* If the execpted size is a constant value, __bos can see it. */ 156 #define check_const(_expected, alloc, free) do { \ 157 size_t expected = (_expected); \ 158 void *p = alloc; \ 159 KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n"); \ 160 KUNIT_EXPECT_BOS(test, p, expected, #alloc); \ 161 KUNIT_EXPECT_BDOS(test, p, expected, #alloc); \ 162 free; \ 163 } while (0) 164 165 /* If the execpted size is NOT a constant value, __bos CANNOT see it. */ 166 #define check_dynamic(_expected, alloc, free) do { \ 167 size_t expected = (_expected); \ 168 void *p = alloc; \ 169 KUNIT_EXPECT_TRUE_MSG(test, p != NULL, #alloc " failed?!\n"); \ 170 KUNIT_EXPECT_BOS(test, p, SIZE_MAX, #alloc); \ 171 KUNIT_EXPECT_BDOS(test, p, expected, #alloc); \ 172 free; \ 173 } while (0) 174 175 /* Assortment of constant-value kinda-edge cases. */ 176 #define CONST_TEST_BODY(TEST_alloc) do { \ 177 /* Special-case vmalloc()-family to skip 0-sized allocs. */ \ 178 if (strcmp(#TEST_alloc, "TEST_vmalloc") != 0) \ 179 TEST_alloc(check_const, 0, 0); \ 180 TEST_alloc(check_const, 1, 1); \ 181 TEST_alloc(check_const, 128, 128); \ 182 TEST_alloc(check_const, 1023, 1023); \ 183 TEST_alloc(check_const, 1025, 1025); \ 184 TEST_alloc(check_const, 4096, 4096); \ 185 TEST_alloc(check_const, 4097, 4097); \ 186 } while (0) 187 188 static volatile size_t zero_size; 189 static volatile size_t unknown_size = 50; 190 191 #if !__has_builtin(__builtin_dynamic_object_size) 192 #define DYNAMIC_TEST_BODY(TEST_alloc) \ 193 kunit_skip(test, "Compiler is missing __builtin_dynamic_object_size() support\n") 194 #else 195 #define DYNAMIC_TEST_BODY(TEST_alloc) do { \ 196 size_t size = unknown_size; \ 197 \ 198 /* \ 199 * Expected size is "size" in each test, before it is then \ 200 * internally incremented in each test. Requires we disable \ 201 * -Wunsequenced. \ 202 */ \ 203 TEST_alloc(check_dynamic, size, size++); \ 204 /* Make sure incrementing actually happened. */ \ 205 KUNIT_EXPECT_NE(test, size, unknown_size); \ 206 } while (0) 207 #endif 208 209 #define DEFINE_ALLOC_SIZE_TEST_PAIR(allocator) \ 210 static void fortify_test_alloc_size_##allocator##_const(struct kunit *test) \ 211 { \ 212 CONST_TEST_BODY(TEST_##allocator); \ 213 } \ 214 static void fortify_test_alloc_size_##allocator##_dynamic(struct kunit *test) \ 215 { \ 216 DYNAMIC_TEST_BODY(TEST_##allocator); \ 217 } 218 219 #define TEST_kmalloc(checker, expected_size, alloc_size) do { \ 220 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \ 221 void *orig; \ 222 size_t len; \ 223 \ 224 checker(expected_size, kmalloc(alloc_size, gfp), \ 225 kfree(p)); \ 226 checker(expected_size, \ 227 kmalloc_node(alloc_size, gfp, NUMA_NO_NODE), \ 228 kfree(p)); \ 229 checker(expected_size, kzalloc(alloc_size, gfp), \ 230 kfree(p)); \ 231 checker(expected_size, \ 232 kzalloc_node(alloc_size, gfp, NUMA_NO_NODE), \ 233 kfree(p)); \ 234 checker(expected_size, kcalloc(1, alloc_size, gfp), \ 235 kfree(p)); \ 236 checker(expected_size, kcalloc(alloc_size, 1, gfp), \ 237 kfree(p)); \ 238 checker(expected_size, \ 239 kcalloc_node(1, alloc_size, gfp, NUMA_NO_NODE), \ 240 kfree(p)); \ 241 checker(expected_size, \ 242 kcalloc_node(alloc_size, 1, gfp, NUMA_NO_NODE), \ 243 kfree(p)); \ 244 checker(expected_size, kmalloc_array(1, alloc_size, gfp), \ 245 kfree(p)); \ 246 checker(expected_size, kmalloc_array(alloc_size, 1, gfp), \ 247 kfree(p)); \ 248 checker(expected_size, \ 249 kmalloc_array_node(1, alloc_size, gfp, NUMA_NO_NODE), \ 250 kfree(p)); \ 251 checker(expected_size, \ 252 kmalloc_array_node(alloc_size, 1, gfp, NUMA_NO_NODE), \ 253 kfree(p)); \ 254 \ 255 orig = kmalloc(alloc_size, gfp); \ 256 KUNIT_EXPECT_TRUE(test, orig != NULL); \ 257 checker((expected_size) * 2, \ 258 krealloc(orig, (alloc_size) * 2, gfp), \ 259 kfree(p)); \ 260 orig = kmalloc(alloc_size, gfp); \ 261 KUNIT_EXPECT_TRUE(test, orig != NULL); \ 262 checker((expected_size) * 2, \ 263 krealloc_array(orig, 1, (alloc_size) * 2, gfp), \ 264 kfree(p)); \ 265 orig = kmalloc(alloc_size, gfp); \ 266 KUNIT_EXPECT_TRUE(test, orig != NULL); \ 267 checker((expected_size) * 2, \ 268 krealloc_array(orig, (alloc_size) * 2, 1, gfp), \ 269 kfree(p)); \ 270 \ 271 len = 11; \ 272 /* Using memdup() with fixed size, so force unknown length. */ \ 273 if (!__builtin_constant_p(expected_size)) \ 274 len += zero_size; \ 275 checker(len, kmemdup("hello there", len, gfp), kfree(p)); \ 276 } while (0) 277 DEFINE_ALLOC_SIZE_TEST_PAIR(kmalloc) 278 279 /* Sizes are in pages, not bytes. */ 280 #define TEST_vmalloc(checker, expected_pages, alloc_pages) do { \ 281 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \ 282 checker((expected_pages) * PAGE_SIZE, \ 283 vmalloc((alloc_pages) * PAGE_SIZE), vfree(p)); \ 284 checker((expected_pages) * PAGE_SIZE, \ 285 vzalloc((alloc_pages) * PAGE_SIZE), vfree(p)); \ 286 checker((expected_pages) * PAGE_SIZE, \ 287 __vmalloc((alloc_pages) * PAGE_SIZE, gfp), vfree(p)); \ 288 } while (0) 289 DEFINE_ALLOC_SIZE_TEST_PAIR(vmalloc) 290 291 /* Sizes are in pages (and open-coded for side-effects), not bytes. */ 292 #define TEST_kvmalloc(checker, expected_pages, alloc_pages) do { \ 293 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \ 294 size_t prev_size; \ 295 void *orig; \ 296 \ 297 checker((expected_pages) * PAGE_SIZE, \ 298 kvmalloc((alloc_pages) * PAGE_SIZE, gfp), \ 299 kvfree(p)); \ 300 checker((expected_pages) * PAGE_SIZE, \ 301 kvmalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \ 302 kvfree(p)); \ 303 checker((expected_pages) * PAGE_SIZE, \ 304 kvzalloc((alloc_pages) * PAGE_SIZE, gfp), \ 305 kvfree(p)); \ 306 checker((expected_pages) * PAGE_SIZE, \ 307 kvzalloc_node((alloc_pages) * PAGE_SIZE, gfp, NUMA_NO_NODE), \ 308 kvfree(p)); \ 309 checker((expected_pages) * PAGE_SIZE, \ 310 kvcalloc(1, (alloc_pages) * PAGE_SIZE, gfp), \ 311 kvfree(p)); \ 312 checker((expected_pages) * PAGE_SIZE, \ 313 kvcalloc((alloc_pages) * PAGE_SIZE, 1, gfp), \ 314 kvfree(p)); \ 315 checker((expected_pages) * PAGE_SIZE, \ 316 kvmalloc_array(1, (alloc_pages) * PAGE_SIZE, gfp), \ 317 kvfree(p)); \ 318 checker((expected_pages) * PAGE_SIZE, \ 319 kvmalloc_array((alloc_pages) * PAGE_SIZE, 1, gfp), \ 320 kvfree(p)); \ 321 \ 322 prev_size = (expected_pages) * PAGE_SIZE; \ 323 orig = kvmalloc(prev_size, gfp); \ 324 KUNIT_EXPECT_TRUE(test, orig != NULL); \ 325 checker(((expected_pages) * PAGE_SIZE) * 2, \ 326 kvrealloc(orig, ((alloc_pages) * PAGE_SIZE) * 2, gfp), \ 327 kvfree(p)); \ 328 } while (0) 329 DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc) 330 331 #define TEST_devm_kmalloc(checker, expected_size, alloc_size) do { \ 332 gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; \ 333 const char dev_name[] = "fortify-test"; \ 334 struct device *dev; \ 335 void *orig; \ 336 size_t len; \ 337 \ 338 /* Create dummy device for devm_kmalloc()-family tests. */ \ 339 dev = kunit_device_register(test, dev_name); \ 340 KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev), \ 341 "Cannot register test device\n"); \ 342 \ 343 checker(expected_size, devm_kmalloc(dev, alloc_size, gfp), \ 344 devm_kfree(dev, p)); \ 345 checker(expected_size, devm_kzalloc(dev, alloc_size, gfp), \ 346 devm_kfree(dev, p)); \ 347 checker(expected_size, \ 348 devm_kmalloc_array(dev, 1, alloc_size, gfp), \ 349 devm_kfree(dev, p)); \ 350 checker(expected_size, \ 351 devm_kmalloc_array(dev, alloc_size, 1, gfp), \ 352 devm_kfree(dev, p)); \ 353 checker(expected_size, \ 354 devm_kcalloc(dev, 1, alloc_size, gfp), \ 355 devm_kfree(dev, p)); \ 356 checker(expected_size, \ 357 devm_kcalloc(dev, alloc_size, 1, gfp), \ 358 devm_kfree(dev, p)); \ 359 \ 360 orig = devm_kmalloc(dev, alloc_size, gfp); \ 361 KUNIT_EXPECT_TRUE(test, orig != NULL); \ 362 checker((expected_size) * 2, \ 363 devm_krealloc(dev, orig, (alloc_size) * 2, gfp), \ 364 devm_kfree(dev, p)); \ 365 \ 366 len = 4; \ 367 /* Using memdup() with fixed size, so force unknown length. */ \ 368 if (!__builtin_constant_p(expected_size)) \ 369 len += zero_size; \ 370 checker(len, devm_kmemdup(dev, "Ohai", len, gfp), \ 371 devm_kfree(dev, p)); \ 372 \ 373 kunit_device_unregister(test, dev); \ 374 } while (0) 375 DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc) 376 377 static const char * const test_strs[] = { 378 "", 379 "Hello there", 380 "A longer string, just for variety", 381 }; 382 383 #define TEST_realloc(checker) do { \ 384 gfp_t gfp = GFP_KERNEL; \ 385 size_t len; \ 386 int i; \ 387 \ 388 for (i = 0; i < ARRAY_SIZE(test_strs); i++) { \ 389 len = strlen(test_strs[i]); \ 390 KUNIT_EXPECT_EQ(test, __builtin_constant_p(len), 0); \ 391 checker(len, kmemdup_array(test_strs[i], 1, len, gfp), \ 392 kfree(p)); \ 393 checker(len, kmemdup(test_strs[i], len, gfp), \ 394 kfree(p)); \ 395 } \ 396 } while (0) 397 static void fortify_test_realloc_size(struct kunit *test) 398 { 399 TEST_realloc(check_dynamic); 400 } 401 402 /* 403 * We can't have an array at the end of a structure or else 404 * builds without -fstrict-flex-arrays=3 will report them as 405 * being an unknown length. Additionally, add bytes before 406 * and after the string to catch over/underflows if tests 407 * fail. 408 */ 409 struct fortify_padding { 410 unsigned long bytes_before; 411 char buf[32]; 412 unsigned long bytes_after; 413 }; 414 415 static void fortify_test_strlen(struct kunit *test) 416 { 417 struct fortify_padding pad = { }; 418 int i, end = sizeof(pad.buf) - 1; 419 420 /* Fill 31 bytes with valid characters. */ 421 for (i = 0; i < sizeof(pad.buf) - 1; i++) 422 pad.buf[i] = i + '0'; 423 /* Trailing bytes are still %NUL. */ 424 KUNIT_EXPECT_EQ(test, pad.buf[end], '\0'); 425 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 426 427 /* String is terminated, so strlen() is valid. */ 428 KUNIT_EXPECT_EQ(test, strlen(pad.buf), end); 429 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 430 431 /* Make string unterminated, and recount. */ 432 pad.buf[end] = 'A'; 433 end = sizeof(pad.buf); 434 KUNIT_EXPECT_EQ(test, strlen(pad.buf), end); 435 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 436 } 437 438 static void fortify_test_strnlen(struct kunit *test) 439 { 440 struct fortify_padding pad = { }; 441 int i, end = sizeof(pad.buf) - 1; 442 443 /* Fill 31 bytes with valid characters. */ 444 for (i = 0; i < sizeof(pad.buf) - 1; i++) 445 pad.buf[i] = i + '0'; 446 /* Trailing bytes are still %NUL. */ 447 KUNIT_EXPECT_EQ(test, pad.buf[end], '\0'); 448 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 449 450 /* String is terminated, so strnlen() is valid. */ 451 KUNIT_EXPECT_EQ(test, strnlen(pad.buf, sizeof(pad.buf)), end); 452 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 453 /* A truncated strnlen() will be safe, too. */ 454 KUNIT_EXPECT_EQ(test, strnlen(pad.buf, sizeof(pad.buf) / 2), 455 sizeof(pad.buf) / 2); 456 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 457 458 /* Make string unterminated, and recount. */ 459 pad.buf[end] = 'A'; 460 end = sizeof(pad.buf); 461 /* Reading beyond will fail. */ 462 KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end + 1), end); 463 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 464 KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end + 2), end); 465 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 466 467 /* Early-truncated is safe still, though. */ 468 KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end), end); 469 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 470 471 end = sizeof(pad.buf) / 2; 472 KUNIT_EXPECT_EQ(test, strnlen(pad.buf, end), end); 473 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 474 } 475 476 static void fortify_test_strcpy(struct kunit *test) 477 { 478 struct fortify_padding pad = { }; 479 char src[sizeof(pad.buf) + 1] = { }; 480 int i; 481 482 /* Fill 31 bytes with valid characters. */ 483 for (i = 0; i < sizeof(src) - 2; i++) 484 src[i] = i + '0'; 485 486 /* Destination is %NUL-filled to start with. */ 487 KUNIT_EXPECT_EQ(test, pad.bytes_before, 0); 488 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 489 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 490 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 491 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 492 493 /* Legitimate strcpy() 1 less than of max size. */ 494 KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src) 495 == pad.buf); 496 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 497 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 498 /* Only last byte should be %NUL */ 499 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 500 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 501 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 502 503 src[sizeof(src) - 2] = 'A'; 504 /* But now we trip the overflow checking. */ 505 KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src) 506 == pad.buf); 507 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 508 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); 509 /* Trailing %NUL -- thanks to FORTIFY. */ 510 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 511 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 512 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 513 /* And we will not have gone beyond. */ 514 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 515 516 src[sizeof(src) - 1] = 'A'; 517 /* And for sure now, two bytes past. */ 518 KUNIT_ASSERT_TRUE(test, strcpy(pad.buf, src) 519 == pad.buf); 520 /* 521 * Which trips both the strlen() on the unterminated src, 522 * and the resulting copy attempt. 523 */ 524 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 525 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); 526 /* Trailing %NUL -- thanks to FORTIFY. */ 527 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 528 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 529 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 530 /* And we will not have gone beyond. */ 531 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 532 } 533 534 static void fortify_test_strscpy(struct kunit *test) 535 { 536 struct fortify_padding pad = { }; 537 char src[] = "Copy me fully into a small buffer and I will overflow!"; 538 size_t sizeof_buf = sizeof(pad.buf); 539 size_t sizeof_src = sizeof(src); 540 541 OPTIMIZER_HIDE_VAR(sizeof_buf); 542 OPTIMIZER_HIDE_VAR(sizeof_src); 543 544 /* Destination is %NUL-filled to start with. */ 545 KUNIT_EXPECT_EQ(test, pad.bytes_before, 0); 546 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0'); 547 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 2], '\0'); 548 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 3], '\0'); 549 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 550 551 /* Legitimate strscpy() 1 less than of max size. */ 552 KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_buf - 1), 553 -E2BIG); 554 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 555 /* Keeping space for %NUL, last two bytes should be %NUL */ 556 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0'); 557 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 2], '\0'); 558 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 3], '\0'); 559 560 /* Legitimate max-size strscpy. */ 561 KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_buf), 562 -E2BIG); 563 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 564 /* A trailing %NUL will exist. */ 565 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0'); 566 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0'); 567 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0'); 568 569 /* Now verify that FORTIFY is working... */ 570 KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_buf + 1), 571 -E2BIG); 572 /* Should catch the overflow. */ 573 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); 574 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0'); 575 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0'); 576 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0'); 577 /* And we will not have gone beyond. */ 578 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 579 580 /* And much further... */ 581 KUNIT_ASSERT_EQ(test, strscpy(pad.buf, src, sizeof_src * 2), 582 -E2BIG); 583 /* Should catch the overflow. */ 584 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); 585 KUNIT_EXPECT_EQ(test, pad.buf[sizeof_buf - 1], '\0'); 586 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0'); 587 KUNIT_EXPECT_NE(test, pad.buf[sizeof_buf - 2], '\0'); 588 /* And we will not have gone beyond. */ 589 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 590 } 591 592 static void fortify_test_strcat(struct kunit *test) 593 { 594 struct fortify_padding pad = { }; 595 char src[sizeof(pad.buf) / 2] = { }; 596 char one[] = "A"; 597 char two[] = "BC"; 598 int i; 599 600 /* Fill 15 bytes with valid characters. */ 601 for (i = 0; i < sizeof(src) - 1; i++) 602 src[i] = i + 'A'; 603 604 /* Destination is %NUL-filled to start with. */ 605 KUNIT_EXPECT_EQ(test, pad.bytes_before, 0); 606 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 607 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 608 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 609 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 610 611 /* Legitimate strcat() using less than half max size. */ 612 KUNIT_ASSERT_TRUE(test, strcat(pad.buf, src) == pad.buf); 613 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 614 /* Legitimate strcat() now 2 bytes shy of end. */ 615 KUNIT_ASSERT_TRUE(test, strcat(pad.buf, src) == pad.buf); 616 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 617 /* Last two bytes should be %NUL */ 618 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 619 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 620 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 621 622 /* Add one more character to the end. */ 623 KUNIT_ASSERT_TRUE(test, strcat(pad.buf, one) == pad.buf); 624 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 625 /* Last byte should be %NUL */ 626 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 627 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 628 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 629 630 /* And this one char will overflow. */ 631 KUNIT_ASSERT_TRUE(test, strcat(pad.buf, one) == pad.buf); 632 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); 633 /* Last byte should be %NUL thanks to FORTIFY. */ 634 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 635 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 636 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 637 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 638 639 /* And adding two will overflow more. */ 640 KUNIT_ASSERT_TRUE(test, strcat(pad.buf, two) == pad.buf); 641 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); 642 /* Last byte should be %NUL thanks to FORTIFY. */ 643 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 644 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 645 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 646 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 647 } 648 649 static void fortify_test_strncat(struct kunit *test) 650 { 651 struct fortify_padding pad = { }; 652 char src[sizeof(pad.buf)] = { }; 653 int i, partial; 654 655 /* Fill 31 bytes with valid characters. */ 656 partial = sizeof(src) / 2 - 1; 657 for (i = 0; i < partial; i++) 658 src[i] = i + 'A'; 659 660 /* Destination is %NUL-filled to start with. */ 661 KUNIT_EXPECT_EQ(test, pad.bytes_before, 0); 662 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 663 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 664 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 665 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 666 667 /* Legitimate strncat() using less than half max size. */ 668 KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, partial) == pad.buf); 669 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 670 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 671 /* Legitimate strncat() now 2 bytes shy of end. */ 672 KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, partial) == pad.buf); 673 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 674 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 675 /* Last two bytes should be %NUL */ 676 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 677 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 678 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 679 680 /* Add one more character to the end. */ 681 KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 1) == pad.buf); 682 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 683 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 684 /* Last byte should be %NUL */ 685 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 686 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 687 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 688 689 /* And this one char will overflow. */ 690 KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 1) == pad.buf); 691 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 692 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); 693 /* Last byte should be %NUL thanks to FORTIFY. */ 694 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 695 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 696 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 697 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 698 699 /* And adding two will overflow more. */ 700 KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 2) == pad.buf); 701 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 702 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); 703 /* Last byte should be %NUL thanks to FORTIFY. */ 704 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 705 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 706 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 707 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 708 709 /* Force an unterminated destination, and overflow. */ 710 pad.buf[sizeof(pad.buf) - 1] = 'A'; 711 KUNIT_ASSERT_TRUE(test, strncat(pad.buf, src, 1) == pad.buf); 712 /* This will have tripped both strlen() and strcat(). */ 713 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 714 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 3); 715 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 716 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 717 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 718 /* But we should not go beyond the end. */ 719 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 720 } 721 722 static void fortify_test_strlcat(struct kunit *test) 723 { 724 struct fortify_padding pad = { }; 725 char src[sizeof(pad.buf)] = { }; 726 int i, partial; 727 int len = sizeof(pad.buf); 728 729 OPTIMIZER_HIDE_VAR(len); 730 731 /* Fill 15 bytes with valid characters. */ 732 partial = sizeof(src) / 2 - 1; 733 for (i = 0; i < partial; i++) 734 src[i] = i + 'A'; 735 736 /* Destination is %NUL-filled to start with. */ 737 KUNIT_EXPECT_EQ(test, pad.bytes_before, 0); 738 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 739 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 740 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 741 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 742 743 /* Legitimate strlcat() using less than half max size. */ 744 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, src, len), partial); 745 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 746 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 747 /* Legitimate strlcat() now 2 bytes shy of end. */ 748 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, src, len), partial * 2); 749 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 750 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 751 /* Last two bytes should be %NUL */ 752 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 753 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 754 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 755 756 /* Add one more character to the end. */ 757 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "Q", len), partial * 2 + 1); 758 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 759 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); 760 /* Last byte should be %NUL */ 761 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 762 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 763 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 764 765 /* And this one char will overflow. */ 766 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "V", len * 2), len); 767 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 768 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); 769 /* Last byte should be %NUL thanks to FORTIFY. */ 770 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 771 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 772 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 773 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 774 775 /* And adding two will overflow more. */ 776 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "QQ", len * 2), len + 1); 777 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 778 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); 779 /* Last byte should be %NUL thanks to FORTIFY. */ 780 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 781 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 782 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 783 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 784 785 /* Force an unterminated destination, and overflow. */ 786 pad.buf[sizeof(pad.buf) - 1] = 'A'; 787 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, "TT", len * 2), len + 2); 788 /* This will have tripped both strlen() and strlcat(). */ 789 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 790 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); 791 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 792 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 2], '\0'); 793 KUNIT_EXPECT_NE(test, pad.buf[sizeof(pad.buf) - 3], '\0'); 794 /* But we should not go beyond the end. */ 795 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 796 797 /* Force an unterminated source, and overflow. */ 798 memset(src, 'B', sizeof(src)); 799 pad.buf[sizeof(pad.buf) - 1] = '\0'; 800 KUNIT_ASSERT_EQ(test, strlcat(pad.buf, src, len * 3), len - 1 + sizeof(src)); 801 /* This will have tripped both strlen() and strlcat(). */ 802 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 3); 803 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 3); 804 KUNIT_EXPECT_EQ(test, pad.buf[sizeof(pad.buf) - 1], '\0'); 805 /* But we should not go beyond the end. */ 806 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); 807 } 808 809 /* Check for 0-sized arrays... */ 810 struct fortify_zero_sized { 811 unsigned long bytes_before; 812 char buf[0]; 813 unsigned long bytes_after; 814 }; 815 816 #define __fortify_test(memfunc) \ 817 static void fortify_test_##memfunc(struct kunit *test) \ 818 { \ 819 struct fortify_zero_sized empty = { }; \ 820 struct fortify_padding pad = { }; \ 821 char srcA[sizeof(pad.buf) + 2]; \ 822 char srcB[sizeof(pad.buf) + 2]; \ 823 size_t len = sizeof(pad.buf); \ 824 size_t zero = 0; \ 825 \ 826 OPTIMIZER_HIDE_VAR(len); \ 827 OPTIMIZER_HIDE_VAR(zero); \ 828 \ 829 memset(srcA, 'A', sizeof(srcA)); \ 830 KUNIT_ASSERT_EQ(test, srcA[0], 'A'); \ 831 memset(srcB, 'B', sizeof(srcB)); \ 832 KUNIT_ASSERT_EQ(test, srcB[0], 'B'); \ 833 \ 834 memfunc(pad.buf, srcA, zero); \ 835 KUNIT_EXPECT_EQ(test, pad.buf[0], '\0'); \ 836 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 837 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \ 838 memfunc(pad.buf + 1, srcB, zero + 1); \ 839 KUNIT_EXPECT_EQ(test, pad.buf[0], '\0'); \ 840 KUNIT_EXPECT_EQ(test, pad.buf[1], 'B'); \ 841 KUNIT_EXPECT_EQ(test, pad.buf[2], '\0'); \ 842 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 843 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \ 844 memfunc(pad.buf, srcA, zero + 1); \ 845 KUNIT_EXPECT_EQ(test, pad.buf[0], 'A'); \ 846 KUNIT_EXPECT_EQ(test, pad.buf[1], 'B'); \ 847 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 848 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \ 849 memfunc(pad.buf, srcA, len - 1); \ 850 KUNIT_EXPECT_EQ(test, pad.buf[1], 'A'); \ 851 KUNIT_EXPECT_EQ(test, pad.buf[len - 1], '\0'); \ 852 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 853 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \ 854 memfunc(pad.buf, srcA, len); \ 855 KUNIT_EXPECT_EQ(test, pad.buf[1], 'A'); \ 856 KUNIT_EXPECT_EQ(test, pad.buf[len - 1], 'A'); \ 857 KUNIT_EXPECT_EQ(test, pad.bytes_after, 0); \ 858 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 859 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \ 860 memfunc(pad.buf, srcA, len + 1); \ 861 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 862 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); \ 863 memfunc(pad.buf + 1, srcB, len); \ 864 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 865 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 2); \ 866 \ 867 /* Reset error counter. */ \ 868 fortify_write_overflows = 0; \ 869 /* Copy nothing into nothing: no errors. */ \ 870 memfunc(empty.buf, srcB, zero); \ 871 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 872 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 0); \ 873 memfunc(empty.buf, srcB, zero + 1); \ 874 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); \ 875 KUNIT_EXPECT_EQ(test, fortify_write_overflows, 1); \ 876 } 877 __fortify_test(memcpy) 878 __fortify_test(memmove) 879 880 static void fortify_test_memscan(struct kunit *test) 881 { 882 char haystack[] = "Where oh where is my memory range?"; 883 char *mem = haystack + strlen("Where oh where is "); 884 char needle = 'm'; 885 size_t len = sizeof(haystack); 886 887 OPTIMIZER_HIDE_VAR(len); 888 889 KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len), 890 mem); 891 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 892 /* Catch too-large range. */ 893 KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len + 1), 894 NULL); 895 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 896 KUNIT_ASSERT_PTR_EQ(test, memscan(haystack, needle, len * 2), 897 NULL); 898 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 899 } 900 901 static void fortify_test_memchr(struct kunit *test) 902 { 903 char haystack[] = "Where oh where is my memory range?"; 904 char *mem = haystack + strlen("Where oh where is "); 905 char needle = 'm'; 906 size_t len = sizeof(haystack); 907 908 OPTIMIZER_HIDE_VAR(len); 909 910 KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len), 911 mem); 912 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 913 /* Catch too-large range. */ 914 KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len + 1), 915 NULL); 916 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 917 KUNIT_ASSERT_PTR_EQ(test, memchr(haystack, needle, len * 2), 918 NULL); 919 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 920 } 921 922 static void fortify_test_memchr_inv(struct kunit *test) 923 { 924 char haystack[] = "Where oh where is my memory range?"; 925 char *mem = haystack + 1; 926 char needle = 'W'; 927 size_t len = sizeof(haystack); 928 929 OPTIMIZER_HIDE_VAR(len); 930 931 /* Normal search is okay. */ 932 KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len), 933 mem); 934 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 935 /* Catch too-large range. */ 936 KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len + 1), 937 NULL); 938 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 939 KUNIT_ASSERT_PTR_EQ(test, memchr_inv(haystack, needle, len * 2), 940 NULL); 941 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 942 } 943 944 static void fortify_test_memcmp(struct kunit *test) 945 { 946 char one[] = "My mind is going ..."; 947 char two[] = "My mind is going ... I can feel it."; 948 volatile size_t one_len = sizeof(one) - 1; 949 volatile size_t two_len = sizeof(two) - 1; 950 951 OPTIMIZER_HIDE_VAR(one_len); 952 OPTIMIZER_HIDE_VAR(two_len); 953 954 /* We match the first string (ignoring the %NUL). */ 955 KUNIT_ASSERT_EQ(test, memcmp(one, two, one_len), 0); 956 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 957 /* Still in bounds, but no longer matching. */ 958 KUNIT_ASSERT_LT(test, memcmp(one, two, one_len + 1), 0); 959 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 960 961 /* Catch too-large ranges. */ 962 KUNIT_ASSERT_EQ(test, memcmp(one, two, one_len + 2), INT_MIN); 963 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 964 965 KUNIT_ASSERT_EQ(test, memcmp(two, one, two_len + 2), INT_MIN); 966 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 967 } 968 969 static void fortify_test_kmemdup(struct kunit *test) 970 { 971 char src[] = "I got Doom running on it!"; 972 char *copy; 973 size_t len = sizeof(src); 974 975 OPTIMIZER_HIDE_VAR(len); 976 977 /* Copy is within bounds. */ 978 copy = kmemdup(src, len, GFP_KERNEL); 979 KUNIT_EXPECT_NOT_NULL(test, copy); 980 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 981 kfree(copy); 982 983 /* Without %NUL. */ 984 copy = kmemdup(src, len - 1, GFP_KERNEL); 985 KUNIT_EXPECT_NOT_NULL(test, copy); 986 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 987 kfree(copy); 988 989 /* Tiny bounds. */ 990 copy = kmemdup(src, 1, GFP_KERNEL); 991 KUNIT_EXPECT_NOT_NULL(test, copy); 992 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 0); 993 kfree(copy); 994 995 /* Out of bounds by 1 byte. */ 996 copy = kmemdup(src, len + 1, GFP_KERNEL); 997 KUNIT_EXPECT_PTR_EQ(test, copy, ZERO_SIZE_PTR); 998 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 1); 999 kfree(copy); 1000 1001 /* Way out of bounds. */ 1002 copy = kmemdup(src, len * 2, GFP_KERNEL); 1003 KUNIT_EXPECT_PTR_EQ(test, copy, ZERO_SIZE_PTR); 1004 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 2); 1005 kfree(copy); 1006 1007 /* Starting offset causing out of bounds. */ 1008 copy = kmemdup(src + 1, len, GFP_KERNEL); 1009 KUNIT_EXPECT_PTR_EQ(test, copy, ZERO_SIZE_PTR); 1010 KUNIT_EXPECT_EQ(test, fortify_read_overflows, 3); 1011 kfree(copy); 1012 } 1013 1014 static int fortify_test_init(struct kunit *test) 1015 { 1016 if (!IS_ENABLED(CONFIG_FORTIFY_SOURCE)) 1017 kunit_skip(test, "Not built with CONFIG_FORTIFY_SOURCE=y"); 1018 1019 fortify_read_overflows = 0; 1020 kunit_add_named_resource(test, NULL, NULL, &read_resource, 1021 "fortify_read_overflows", 1022 &fortify_read_overflows); 1023 fortify_write_overflows = 0; 1024 kunit_add_named_resource(test, NULL, NULL, &write_resource, 1025 "fortify_write_overflows", 1026 &fortify_write_overflows); 1027 return 0; 1028 } 1029 1030 static struct kunit_case fortify_test_cases[] = { 1031 KUNIT_CASE(fortify_test_known_sizes), 1032 KUNIT_CASE(fortify_test_control_flow_split), 1033 KUNIT_CASE(fortify_test_alloc_size_kmalloc_const), 1034 KUNIT_CASE(fortify_test_alloc_size_kmalloc_dynamic), 1035 KUNIT_CASE(fortify_test_alloc_size_vmalloc_const), 1036 KUNIT_CASE(fortify_test_alloc_size_vmalloc_dynamic), 1037 KUNIT_CASE(fortify_test_alloc_size_kvmalloc_const), 1038 KUNIT_CASE(fortify_test_alloc_size_kvmalloc_dynamic), 1039 KUNIT_CASE(fortify_test_alloc_size_devm_kmalloc_const), 1040 KUNIT_CASE(fortify_test_alloc_size_devm_kmalloc_dynamic), 1041 KUNIT_CASE(fortify_test_realloc_size), 1042 KUNIT_CASE(fortify_test_strlen), 1043 KUNIT_CASE(fortify_test_strnlen), 1044 KUNIT_CASE(fortify_test_strcpy), 1045 KUNIT_CASE(fortify_test_strscpy), 1046 KUNIT_CASE(fortify_test_strcat), 1047 KUNIT_CASE(fortify_test_strncat), 1048 KUNIT_CASE(fortify_test_strlcat), 1049 /* skip memset: performs bounds checking on whole structs */ 1050 KUNIT_CASE(fortify_test_memcpy), 1051 KUNIT_CASE(fortify_test_memmove), 1052 KUNIT_CASE(fortify_test_memscan), 1053 KUNIT_CASE(fortify_test_memchr), 1054 KUNIT_CASE(fortify_test_memchr_inv), 1055 KUNIT_CASE(fortify_test_memcmp), 1056 KUNIT_CASE(fortify_test_kmemdup), 1057 {} 1058 }; 1059 1060 static struct kunit_suite fortify_test_suite = { 1061 .name = "fortify", 1062 .init = fortify_test_init, 1063 .test_cases = fortify_test_cases, 1064 }; 1065 1066 kunit_test_suite(fortify_test_suite); 1067 1068 MODULE_DESCRIPTION("Runtime test cases for CONFIG_FORTIFY_SOURCE"); 1069 MODULE_LICENSE("GPL"); 1070