lib/test_kasan.c

   1 /*
   2  *
   3  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   4  * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #define pr_fmt(fmt) "kasan test: %s " fmt, __func__
  13
  14 #include <linux/delay.h>
  15 #include <linux/kernel.h>
  16 #include <linux/mman.h>
  17 #include <linux/mm.h>
  18 #include <linux/printk.h>
  19 #include <linux/slab.h>
  20 #include <linux/string.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/module.h>
  23 #include <linux/kasan.h>
  24
  25 /*
  26  * Note: test functions are marked noinline so that their names appear in
  27  * reports.
  28  */
  29
  30 static noinline void __init kmalloc_oob_right(void)
  31 {
  32         char *ptr;
  33         size_t size = 123;
  34
  35         pr_info("out-of-bounds to right\n");
  36         ptr = kmalloc(size, GFP_KERNEL);
  37         if (!ptr) {
  38                 pr_err("Allocation failed\n");
  39                 return;
  40         }
  41
  42         ptr[size] = 'x';
  43         kfree(ptr);
  44 }
  45
  46 static noinline void __init kmalloc_oob_left(void)
  47 {
  48         char *ptr;
  49         size_t size = 15;
  50
  51         pr_info("out-of-bounds to left\n");
  52         ptr = kmalloc(size, GFP_KERNEL);
  53         if (!ptr) {
  54                 pr_err("Allocation failed\n");
  55                 return;
  56         }
  57
  58         *ptr = *(ptr - 1);
  59         kfree(ptr);
  60 }
  61
  62 static noinline void __init kmalloc_node_oob_right(void)
  63 {
  64         char *ptr;
  65         size_t size = 4096;
  66
  67         pr_info("kmalloc_node(): out-of-bounds to right\n");
  68         ptr = kmalloc_node(size, GFP_KERNEL, 0);
  69         if (!ptr) {
  70                 pr_err("Allocation failed\n");
  71                 return;
  72         }
  73
  74         ptr[size] = 0;
  75         kfree(ptr);
  76 }
  77
  78 #ifdef CONFIG_SLUB
  79 static noinline void __init kmalloc_pagealloc_oob_right(void)
  80 {
  81         char *ptr;
  82         size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
  83
  84         /* Allocate a chunk that does not fit into a SLUB cache to trigger
  85          * the page allocator fallback.
  86          */
  87         pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
  88         ptr = kmalloc(size, GFP_KERNEL);
  89         if (!ptr) {
  90                 pr_err("Allocation failed\n");
  91                 return;
  92         }
  93
  94         ptr[size] = 0;
  95         kfree(ptr);
  96 }
  97
  98 static noinline void __init kmalloc_pagealloc_uaf(void)
  99 {
 100         char *ptr;
 101         size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
 102
 103         pr_info("kmalloc pagealloc allocation: use-after-free\n");
 104         ptr = kmalloc(size, GFP_KERNEL);
 105         if (!ptr) {
 106                 pr_err("Allocation failed\n");
 107                 return;
 108         }
 109
 110         kfree(ptr);
 111         ptr[0] = 0;
 112 }
 113
 114 static noinline void __init kmalloc_pagealloc_invalid_free(void)
 115 {
 116         char *ptr;
 117         size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
 118
 119         pr_info("kmalloc pagealloc allocation: invalid-free\n");
 120         ptr = kmalloc(size, GFP_KERNEL);
 121         if (!ptr) {
 122                 pr_err("Allocation failed\n");
 123                 return;
 124         }
 125
 126         kfree(ptr + 1);
 127 }
 128 #endif
 129
 130 static noinline void __init kmalloc_large_oob_right(void)
 131 {
 132         char *ptr;
 133         size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
 134         /* Allocate a chunk that is large enough, but still fits into a slab
 135          * and does not trigger the page allocator fallback in SLUB.
 136          */
 137         pr_info("kmalloc large allocation: out-of-bounds to right\n");
 138         ptr = kmalloc(size, GFP_KERNEL);
 139         if (!ptr) {
 140                 pr_err("Allocation failed\n");
 141                 return;
 142         }
 143
 144         ptr[size] = 0;
 145         kfree(ptr);
 146 }
 147
 148 static noinline void __init kmalloc_oob_krealloc_more(void)
 149 {
 150         char *ptr1, *ptr2;
 151         size_t size1 = 17;
 152         size_t size2 = 19;
 153
 154         pr_info("out-of-bounds after krealloc more\n");
 155         ptr1 = kmalloc(size1, GFP_KERNEL);
 156         ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
 157         if (!ptr1 || !ptr2) {
 158                 pr_err("Allocation failed\n");
 159                 kfree(ptr1);
 160                 kfree(ptr2);
 161                 return;
 162         }
 163
 164         ptr2[size2] = 'x';
 165         kfree(ptr2);
 166 }
 167
 168 static noinline void __init kmalloc_oob_krealloc_less(void)
 169 {
 170         char *ptr1, *ptr2;
 171         size_t size1 = 17;
 172         size_t size2 = 15;
 173
 174         pr_info("out-of-bounds after krealloc less\n");
 175         ptr1 = kmalloc(size1, GFP_KERNEL);
 176         ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
 177         if (!ptr1 || !ptr2) {
 178                 pr_err("Allocation failed\n");
 179                 kfree(ptr1);
 180                 return;
 181         }
 182         ptr2[size2] = 'x';
 183         kfree(ptr2);
 184 }
 185
 186 static noinline void __init kmalloc_oob_16(void)
 187 {
 188         struct {
 189                 u64 words[2];
 190         } *ptr1, *ptr2;
 191
 192         pr_info("kmalloc out-of-bounds for 16-bytes access\n");
 193         ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
 194         ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
 195         if (!ptr1 || !ptr2) {
 196                 pr_err("Allocation failed\n");
 197                 kfree(ptr1);
 198                 kfree(ptr2);
 199                 return;
 200         }
 201         *ptr1 = *ptr2;
 202         kfree(ptr1);
 203         kfree(ptr2);
 204 }
 205
 206 static noinline void __init kmalloc_oob_memset_2(void)
 207 {
 208         char *ptr;
 209         size_t size = 8;
 210
 211         pr_info("out-of-bounds in memset2\n");
 212         ptr = kmalloc(size, GFP_KERNEL);
 213         if (!ptr) {
 214                 pr_err("Allocation failed\n");
 215                 return;
 216         }
 217
 218         memset(ptr+7, 0, 2);
 219         kfree(ptr);
 220 }
 221
 222 static noinline void __init kmalloc_oob_memset_4(void)
 223 {
 224         char *ptr;
 225         size_t size = 8;
 226
 227         pr_info("out-of-bounds in memset4\n");
 228         ptr = kmalloc(size, GFP_KERNEL);
 229         if (!ptr) {
 230                 pr_err("Allocation failed\n");
 231                 return;
 232         }
 233
 234         memset(ptr+5, 0, 4);
 235         kfree(ptr);
 236 }
 237
 238
 239 static noinline void __init kmalloc_oob_memset_8(void)
 240 {
 241         char *ptr;
 242         size_t size = 8;
 243
 244         pr_info("out-of-bounds in memset8\n");
 245         ptr = kmalloc(size, GFP_KERNEL);
 246         if (!ptr) {
 247                 pr_err("Allocation failed\n");
 248                 return;
 249         }
 250
 251         memset(ptr+1, 0, 8);
 252         kfree(ptr);
 253 }
 254
 255 static noinline void __init kmalloc_oob_memset_16(void)
 256 {
 257         char *ptr;
 258         size_t size = 16;
 259
 260         pr_info("out-of-bounds in memset16\n");
 261         ptr = kmalloc(size, GFP_KERNEL);
 262         if (!ptr) {
 263                 pr_err("Allocation failed\n");
 264                 return;
 265         }
 266
 267         memset(ptr+1, 0, 16);
 268         kfree(ptr);
 269 }
 270
 271 static noinline void __init kmalloc_oob_in_memset(void)
 272 {
 273         char *ptr;
 274         size_t size = 666;
 275
 276         pr_info("out-of-bounds in memset\n");
 277         ptr = kmalloc(size, GFP_KERNEL);
 278         if (!ptr) {
 279                 pr_err("Allocation failed\n");
 280                 return;
 281         }
 282
 283         memset(ptr, 0, size+5);
 284         kfree(ptr);
 285 }
 286
 287 static noinline void __init kmalloc_uaf(void)
 288 {
 289         char *ptr;
 290         size_t size = 10;
 291
 292         pr_info("use-after-free\n");
 293         ptr = kmalloc(size, GFP_KERNEL);
 294         if (!ptr) {
 295                 pr_err("Allocation failed\n");
 296                 return;
 297         }
 298
 299         kfree(ptr);
 300         *(ptr + 8) = 'x';
 301 }
 302
 303 static noinline void __init kmalloc_uaf_memset(void)
 304 {
 305         char *ptr;
 306         size_t size = 33;
 307
 308         pr_info("use-after-free in memset\n");
 309         ptr = kmalloc(size, GFP_KERNEL);
 310         if (!ptr) {
 311                 pr_err("Allocation failed\n");
 312                 return;
 313         }
 314
 315         kfree(ptr);
 316         memset(ptr, 0, size);
 317 }
 318
 319 static noinline void __init kmalloc_uaf2(void)
 320 {
 321         char *ptr1, *ptr2;
 322         size_t size = 43;
 323
 324         pr_info("use-after-free after another kmalloc\n");
 325         ptr1 = kmalloc(size, GFP_KERNEL);
 326         if (!ptr1) {
 327                 pr_err("Allocation failed\n");
 328                 return;
 329         }
 330
 331         kfree(ptr1);
 332         ptr2 = kmalloc(size, GFP_KERNEL);
 333         if (!ptr2) {
 334                 pr_err("Allocation failed\n");
 335                 return;
 336         }
 337
 338         ptr1[40] = 'x';
 339         if (ptr1 == ptr2)
 340                 pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
 341         kfree(ptr2);
 342 }
 343
 344 static noinline void __init kmem_cache_oob(void)
 345 {
 346         char *p;
 347         size_t size = 200;
 348         struct kmem_cache *cache = kmem_cache_create("test_cache",
 349                                                 size, 0,
 350                                                 0, NULL);
 351         if (!cache) {
 352                 pr_err("Cache allocation failed\n");
 353                 return;
 354         }
 355         pr_info("out-of-bounds in kmem_cache_alloc\n");
 356         p = kmem_cache_alloc(cache, GFP_KERNEL);
 357         if (!p) {
 358                 pr_err("Allocation failed\n");
 359                 kmem_cache_destroy(cache);
 360                 return;
 361         }
 362
 363         *p = p[size];
 364         kmem_cache_free(cache, p);
 365         kmem_cache_destroy(cache);
 366 }
 367
 368 static noinline void __init memcg_accounted_kmem_cache(void)
 369 {
 370         int i;
 371         char *p;
 372         size_t size = 200;
 373         struct kmem_cache *cache;
 374
 375         cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
 376         if (!cache) {
 377                 pr_err("Cache allocation failed\n");
 378                 return;
 379         }
 380
 381         pr_info("allocate memcg accounted object\n");
 382         /*
 383          * Several allocations with a delay to allow for lazy per memcg kmem
 384          * cache creation.
 385          */
 386         for (i = 0; i < 5; i++) {
 387                 p = kmem_cache_alloc(cache, GFP_KERNEL);
 388                 if (!p)
 389                         goto free_cache;
 390
 391                 kmem_cache_free(cache, p);
 392                 msleep(100);
 393         }
 394
 395 free_cache:
 396         kmem_cache_destroy(cache);
 397 }
 398
 399 static char global_array[10];
 400
 401 static noinline void __init kasan_global_oob(void)
 402 {
 403         volatile int i = 3;
 404         char *p = &global_array[ARRAY_SIZE(global_array) + i];
 405
 406         pr_info("out-of-bounds global variable\n");
 407         *(volatile char *)p;
 408 }
 409
 410 static noinline void __init kasan_stack_oob(void)
 411 {
 412         char stack_array[10];
 413         volatile int i = 0;
 414         char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
 415
 416         pr_info("out-of-bounds on stack\n");
 417         *(volatile char *)p;
 418 }
 419
 420 static noinline void __init ksize_unpoisons_memory(void)
 421 {
 422         char *ptr;
 423         size_t size = 123, real_size;
 424
 425         pr_info("ksize() unpoisons the whole allocated chunk\n");
 426         ptr = kmalloc(size, GFP_KERNEL);
 427         if (!ptr) {
 428                 pr_err("Allocation failed\n");
 429                 return;
 430         }
 431         real_size = ksize(ptr);
 432         /* This access doesn't trigger an error. */
 433         ptr[size] = 'x';
 434         /* This one does. */
 435         ptr[real_size] = 'y';
 436         kfree(ptr);
 437 }
 438
 439 static noinline void __init copy_user_test(void)
 440 {
 441         char *kmem;
 442         char __user *usermem;
 443         size_t size = 10;
 444         int unused;
 445
 446         kmem = kmalloc(size, GFP_KERNEL);
 447         if (!kmem)
 448                 return;
 449
 450         usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
 451                             PROT_READ | PROT_WRITE | PROT_EXEC,
 452                             MAP_ANONYMOUS | MAP_PRIVATE, 0);
 453         if (IS_ERR(usermem)) {
 454                 pr_err("Failed to allocate user memory\n");
 455                 kfree(kmem);
 456                 return;
 457         }
 458
 459         pr_info("out-of-bounds in copy_from_user()\n");
 460         unused = copy_from_user(kmem, usermem, size + 1);
 461
 462         pr_info("out-of-bounds in copy_to_user()\n");
 463         unused = copy_to_user(usermem, kmem, size + 1);
 464
 465         pr_info("out-of-bounds in __copy_from_user()\n");
 466         unused = __copy_from_user(kmem, usermem, size + 1);
 467
 468         pr_info("out-of-bounds in __copy_to_user()\n");
 469         unused = __copy_to_user(usermem, kmem, size + 1);
 470
 471         pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
 472         unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
 473
 474         pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
 475         unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
 476
 477         pr_info("out-of-bounds in strncpy_from_user()\n");
 478         unused = strncpy_from_user(kmem, usermem, size + 1);
 479
 480         vm_munmap((unsigned long)usermem, PAGE_SIZE);
 481         kfree(kmem);
 482 }
 483
 484 static noinline void __init use_after_scope_test(void)
 485 {
 486         volatile char *volatile p;
 487
 488         pr_info("use-after-scope on int\n");
 489         {
 490                 int local = 0;
 491
 492                 p = (char *)&local;
 493         }
 494         p[0] = 1;
 495         p[3] = 1;
 496
 497         pr_info("use-after-scope on array\n");
 498         {
 499                 char local[1024] = {0};
 500
 501                 p = local;
 502         }
 503         p[0] = 1;
 504         p[1023] = 1;
 505 }
 506
 507 static noinline void __init kasan_alloca_oob_left(void)
 508 {
 509         volatile int i = 10;
 510         char alloca_array[i];
 511         char *p = alloca_array - 1;
 512
 513         pr_info("out-of-bounds to left on alloca\n");
 514         *(volatile char *)p;
 515 }
 516
 517 static noinline void __init kasan_alloca_oob_right(void)
 518 {
 519         volatile int i = 10;
 520         char alloca_array[i];
 521         char *p = alloca_array + i;
 522
 523         pr_info("out-of-bounds to right on alloca\n");
 524         *(volatile char *)p;
 525 }
 526
 527 static noinline void __init kmem_cache_double_free(void)
 528 {
 529         char *p;
 530         size_t size = 200;
 531         struct kmem_cache *cache;
 532
 533         cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
 534         if (!cache) {
 535                 pr_err("Cache allocation failed\n");
 536                 return;
 537         }
 538         pr_info("double-free on heap object\n");
 539         p = kmem_cache_alloc(cache, GFP_KERNEL);
 540         if (!p) {
 541                 pr_err("Allocation failed\n");
 542                 kmem_cache_destroy(cache);
 543                 return;
 544         }
 545
 546         kmem_cache_free(cache, p);
 547         kmem_cache_free(cache, p);
 548         kmem_cache_destroy(cache);
 549 }
 550
 551 static noinline void __init kmem_cache_invalid_free(void)
 552 {
 553         char *p;
 554         size_t size = 200;
 555         struct kmem_cache *cache;
 556
 557         cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
 558                                   NULL);
 559         if (!cache) {
 560                 pr_err("Cache allocation failed\n");
 561                 return;
 562         }
 563         pr_info("invalid-free of heap object\n");
 564         p = kmem_cache_alloc(cache, GFP_KERNEL);
 565         if (!p) {
 566                 pr_err("Allocation failed\n");
 567                 kmem_cache_destroy(cache);
 568                 return;
 569         }
 570
 571         /* Trigger invalid free, the object doesn't get freed */
 572         kmem_cache_free(cache, p + 1);
 573
 574         /*
 575          * Properly free the object to prevent the "Objects remaining in
 576          * test_cache on __kmem_cache_shutdown" BUG failure.
 577          */
 578         kmem_cache_free(cache, p);
 579
 580         kmem_cache_destroy(cache);
 581 }
 582
 583 static int __init kmalloc_tests_init(void)
 584 {
 585         /*
 586          * Temporarily enable multi-shot mode. Otherwise, we'd only get a
 587          * report for the first case.
 588          */
 589         bool multishot = kasan_save_enable_multi_shot();
 590
 591         kmalloc_oob_right();
 592         kmalloc_oob_left();
 593         kmalloc_node_oob_right();
 594 #ifdef CONFIG_SLUB
 595         kmalloc_pagealloc_oob_right();
 596         kmalloc_pagealloc_uaf();
 597         kmalloc_pagealloc_invalid_free();
 598 #endif
 599         kmalloc_large_oob_right();
 600         kmalloc_oob_krealloc_more();
 601         kmalloc_oob_krealloc_less();
 602         kmalloc_oob_16();
 603         kmalloc_oob_in_memset();
 604         kmalloc_oob_memset_2();
 605         kmalloc_oob_memset_4();
 606         kmalloc_oob_memset_8();
 607         kmalloc_oob_memset_16();
 608         kmalloc_uaf();
 609         kmalloc_uaf_memset();
 610         kmalloc_uaf2();
 611         kmem_cache_oob();
 612         memcg_accounted_kmem_cache();
 613         kasan_stack_oob();
 614         kasan_global_oob();
 615         kasan_alloca_oob_left();
 616         kasan_alloca_oob_right();
 617         ksize_unpoisons_memory();
 618         copy_user_test();
 619         use_after_scope_test();
 620         kmem_cache_double_free();
 621         kmem_cache_invalid_free();
 622
 623         kasan_restore_multi_shot(multishot);
 624
 625         return -EAGAIN;
 626 }
 627
 628 module_init(kmalloc_tests_init);
 629 MODULE_LICENSE("GPL");