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
  24 /*
  25  * Note: test functions are marked noinline so that their names appear in
  26  * reports.
  27  */
  28
  29 static noinline void __init kmalloc_oob_right(void)
  30 {
  31         char *ptr;
  32         size_t size = 123;
  33
  34         pr_info("out-of-bounds to right\n");
  35         ptr = kmalloc(size, GFP_KERNEL);
  36         if (!ptr) {
  37                 pr_err("Allocation failed\n");
  38                 return;
  39         }
  40
  41         ptr[size] = 'x';
  42         kfree(ptr);
  43 }
  44
  45 static noinline void __init kmalloc_oob_left(void)
  46 {
  47         char *ptr;
  48         size_t size = 15;
  49
  50         pr_info("out-of-bounds to left\n");
  51         ptr = kmalloc(size, GFP_KERNEL);
  52         if (!ptr) {
  53                 pr_err("Allocation failed\n");
  54                 return;
  55         }
  56
  57         *ptr = *(ptr - 1);
  58         kfree(ptr);
  59 }
  60
  61 static noinline void __init kmalloc_node_oob_right(void)
  62 {
  63         char *ptr;
  64         size_t size = 4096;
  65
  66         pr_info("kmalloc_node(): out-of-bounds to right\n");
  67         ptr = kmalloc_node(size, GFP_KERNEL, 0);
  68         if (!ptr) {
  69                 pr_err("Allocation failed\n");
  70                 return;
  71         }
  72
  73         ptr[size] = 0;
  74         kfree(ptr);
  75 }
  76
  77 #ifdef CONFIG_SLUB
  78 static noinline void __init kmalloc_pagealloc_oob_right(void)
  79 {
  80         char *ptr;
  81         size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
  82
  83         /* Allocate a chunk that does not fit into a SLUB cache to trigger
  84          * the page allocator fallback.
  85          */
  86         pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
  87         ptr = kmalloc(size, GFP_KERNEL);
  88         if (!ptr) {
  89                 pr_err("Allocation failed\n");
  90                 return;
  91         }
  92
  93         ptr[size] = 0;
  94         kfree(ptr);
  95 }
  96 #endif
  97
  98 static noinline void __init kmalloc_large_oob_right(void)
  99 {
 100         char *ptr;
 101         size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
 102         /* Allocate a chunk that is large enough, but still fits into a slab
 103          * and does not trigger the page allocator fallback in SLUB.
 104          */
 105         pr_info("kmalloc large allocation: out-of-bounds to right\n");
 106         ptr = kmalloc(size, GFP_KERNEL);
 107         if (!ptr) {
 108                 pr_err("Allocation failed\n");
 109                 return;
 110         }
 111
 112         ptr[size] = 0;
 113         kfree(ptr);
 114 }
 115
 116 static noinline void __init kmalloc_oob_krealloc_more(void)
 117 {
 118         char *ptr1, *ptr2;
 119         size_t size1 = 17;
 120         size_t size2 = 19;
 121
 122         pr_info("out-of-bounds after krealloc more\n");
 123         ptr1 = kmalloc(size1, GFP_KERNEL);
 124         ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
 125         if (!ptr1 || !ptr2) {
 126                 pr_err("Allocation failed\n");
 127                 kfree(ptr1);
 128                 return;
 129         }
 130
 131         ptr2[size2] = 'x';
 132         kfree(ptr2);
 133 }
 134
 135 static noinline void __init kmalloc_oob_krealloc_less(void)
 136 {
 137         char *ptr1, *ptr2;
 138         size_t size1 = 17;
 139         size_t size2 = 15;
 140
 141         pr_info("out-of-bounds after krealloc less\n");
 142         ptr1 = kmalloc(size1, GFP_KERNEL);
 143         ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
 144         if (!ptr1 || !ptr2) {
 145                 pr_err("Allocation failed\n");
 146                 kfree(ptr1);
 147                 return;
 148         }
 149         ptr2[size2] = 'x';
 150         kfree(ptr2);
 151 }
 152
 153 static noinline void __init kmalloc_oob_16(void)
 154 {
 155         struct {
 156                 u64 words[2];
 157         } *ptr1, *ptr2;
 158
 159         pr_info("kmalloc out-of-bounds for 16-bytes access\n");
 160         ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
 161         ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
 162         if (!ptr1 || !ptr2) {
 163                 pr_err("Allocation failed\n");
 164                 kfree(ptr1);
 165                 kfree(ptr2);
 166                 return;
 167         }
 168         *ptr1 = *ptr2;
 169         kfree(ptr1);
 170         kfree(ptr2);
 171 }
 172
 173 static noinline void __init kmalloc_oob_memset_2(void)
 174 {
 175         char *ptr;
 176         size_t size = 8;
 177
 178         pr_info("out-of-bounds in memset2\n");
 179         ptr = kmalloc(size, GFP_KERNEL);
 180         if (!ptr) {
 181                 pr_err("Allocation failed\n");
 182                 return;
 183         }
 184
 185         memset(ptr+7, 0, 2);
 186         kfree(ptr);
 187 }
 188
 189 static noinline void __init kmalloc_oob_memset_4(void)
 190 {
 191         char *ptr;
 192         size_t size = 8;
 193
 194         pr_info("out-of-bounds in memset4\n");
 195         ptr = kmalloc(size, GFP_KERNEL);
 196         if (!ptr) {
 197                 pr_err("Allocation failed\n");
 198                 return;
 199         }
 200
 201         memset(ptr+5, 0, 4);
 202         kfree(ptr);
 203 }
 204
 205
 206 static noinline void __init kmalloc_oob_memset_8(void)
 207 {
 208         char *ptr;
 209         size_t size = 8;
 210
 211         pr_info("out-of-bounds in memset8\n");
 212         ptr = kmalloc(size, GFP_KERNEL);
 213         if (!ptr) {
 214                 pr_err("Allocation failed\n");
 215                 return;
 216         }
 217
 218         memset(ptr+1, 0, 8);
 219         kfree(ptr);
 220 }
 221
 222 static noinline void __init kmalloc_oob_memset_16(void)
 223 {
 224         char *ptr;
 225         size_t size = 16;
 226
 227         pr_info("out-of-bounds in memset16\n");
 228         ptr = kmalloc(size, GFP_KERNEL);
 229         if (!ptr) {
 230                 pr_err("Allocation failed\n");
 231                 return;
 232         }
 233
 234         memset(ptr+1, 0, 16);
 235         kfree(ptr);
 236 }
 237
 238 static noinline void __init kmalloc_oob_in_memset(void)
 239 {
 240         char *ptr;
 241         size_t size = 666;
 242
 243         pr_info("out-of-bounds in memset\n");
 244         ptr = kmalloc(size, GFP_KERNEL);
 245         if (!ptr) {
 246                 pr_err("Allocation failed\n");
 247                 return;
 248         }
 249
 250         memset(ptr, 0, size+5);
 251         kfree(ptr);
 252 }
 253
 254 static noinline void __init kmalloc_uaf(void)
 255 {
 256         char *ptr;
 257         size_t size = 10;
 258
 259         pr_info("use-after-free\n");
 260         ptr = kmalloc(size, GFP_KERNEL);
 261         if (!ptr) {
 262                 pr_err("Allocation failed\n");
 263                 return;
 264         }
 265
 266         kfree(ptr);
 267         *(ptr + 8) = 'x';
 268 }
 269
 270 static noinline void __init kmalloc_uaf_memset(void)
 271 {
 272         char *ptr;
 273         size_t size = 33;
 274
 275         pr_info("use-after-free in memset\n");
 276         ptr = kmalloc(size, GFP_KERNEL);
 277         if (!ptr) {
 278                 pr_err("Allocation failed\n");
 279                 return;
 280         }
 281
 282         kfree(ptr);
 283         memset(ptr, 0, size);
 284 }
 285
 286 static noinline void __init kmalloc_uaf2(void)
 287 {
 288         char *ptr1, *ptr2;
 289         size_t size = 43;
 290
 291         pr_info("use-after-free after another kmalloc\n");
 292         ptr1 = kmalloc(size, GFP_KERNEL);
 293         if (!ptr1) {
 294                 pr_err("Allocation failed\n");
 295                 return;
 296         }
 297
 298         kfree(ptr1);
 299         ptr2 = kmalloc(size, GFP_KERNEL);
 300         if (!ptr2) {
 301                 pr_err("Allocation failed\n");
 302                 return;
 303         }
 304
 305         ptr1[40] = 'x';
 306         if (ptr1 == ptr2)
 307                 pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
 308         kfree(ptr2);
 309 }
 310
 311 static noinline void __init kmem_cache_oob(void)
 312 {
 313         char *p;
 314         size_t size = 200;
 315         struct kmem_cache *cache = kmem_cache_create("test_cache",
 316                                                 size, 0,
 317                                                 0, NULL);
 318         if (!cache) {
 319                 pr_err("Cache allocation failed\n");
 320                 return;
 321         }
 322         pr_info("out-of-bounds in kmem_cache_alloc\n");
 323         p = kmem_cache_alloc(cache, GFP_KERNEL);
 324         if (!p) {
 325                 pr_err("Allocation failed\n");
 326                 kmem_cache_destroy(cache);
 327                 return;
 328         }
 329
 330         *p = p[size];
 331         kmem_cache_free(cache, p);
 332         kmem_cache_destroy(cache);
 333 }
 334
 335 static noinline void __init memcg_accounted_kmem_cache(void)
 336 {
 337         int i;
 338         char *p;
 339         size_t size = 200;
 340         struct kmem_cache *cache;
 341
 342         cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
 343         if (!cache) {
 344                 pr_err("Cache allocation failed\n");
 345                 return;
 346         }
 347
 348         pr_info("allocate memcg accounted object\n");
 349         /*
 350          * Several allocations with a delay to allow for lazy per memcg kmem
 351          * cache creation.
 352          */
 353         for (i = 0; i < 5; i++) {
 354                 p = kmem_cache_alloc(cache, GFP_KERNEL);
 355                 if (!p) {
 356                         pr_err("Allocation failed\n");
 357                         goto free_cache;
 358                 }
 359                 kmem_cache_free(cache, p);
 360                 msleep(100);
 361         }
 362
 363 free_cache:
 364         kmem_cache_destroy(cache);
 365 }
 366
 367 static char global_array[10];
 368
 369 static noinline void __init kasan_global_oob(void)
 370 {
 371         volatile int i = 3;
 372         char *p = &global_array[ARRAY_SIZE(global_array) + i];
 373
 374         pr_info("out-of-bounds global variable\n");
 375         *(volatile char *)p;
 376 }
 377
 378 static noinline void __init kasan_stack_oob(void)
 379 {
 380         char stack_array[10];
 381         volatile int i = 0;
 382         char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
 383
 384         pr_info("out-of-bounds on stack\n");
 385         *(volatile char *)p;
 386 }
 387
 388 static noinline void __init ksize_unpoisons_memory(void)
 389 {
 390         char *ptr;
 391         size_t size = 123, real_size = size;
 392
 393         pr_info("ksize() unpoisons the whole allocated chunk\n");
 394         ptr = kmalloc(size, GFP_KERNEL);
 395         if (!ptr) {
 396                 pr_err("Allocation failed\n");
 397                 return;
 398         }
 399         real_size = ksize(ptr);
 400         /* This access doesn't trigger an error. */
 401         ptr[size] = 'x';
 402         /* This one does. */
 403         ptr[real_size] = 'y';
 404         kfree(ptr);
 405 }
 406
 407 static noinline void __init copy_user_test(void)
 408 {
 409         char *kmem;
 410         char __user *usermem;
 411         size_t size = 10;
 412         int unused;
 413
 414         kmem = kmalloc(size, GFP_KERNEL);
 415         if (!kmem)
 416                 return;
 417
 418         usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
 419                             PROT_READ | PROT_WRITE | PROT_EXEC,
 420                             MAP_ANONYMOUS | MAP_PRIVATE, 0);
 421         if (IS_ERR(usermem)) {
 422                 pr_err("Failed to allocate user memory\n");
 423                 kfree(kmem);
 424                 return;
 425         }
 426
 427         pr_info("out-of-bounds in copy_from_user()\n");
 428         unused = copy_from_user(kmem, usermem, size + 1);
 429
 430         pr_info("out-of-bounds in copy_to_user()\n");
 431         unused = copy_to_user(usermem, kmem, size + 1);
 432
 433         pr_info("out-of-bounds in __copy_from_user()\n");
 434         unused = __copy_from_user(kmem, usermem, size + 1);
 435
 436         pr_info("out-of-bounds in __copy_to_user()\n");
 437         unused = __copy_to_user(usermem, kmem, size + 1);
 438
 439         pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
 440         unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
 441
 442         pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
 443         unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
 444
 445         pr_info("out-of-bounds in strncpy_from_user()\n");
 446         unused = strncpy_from_user(kmem, usermem, size + 1);
 447
 448         vm_munmap((unsigned long)usermem, PAGE_SIZE);
 449         kfree(kmem);
 450 }
 451
 452 static noinline void __init use_after_scope_test(void)
 453 {
 454         volatile char *volatile p;
 455
 456         pr_info("use-after-scope on int\n");
 457         {
 458                 int local = 0;
 459
 460                 p = (char *)&local;
 461         }
 462         p[0] = 1;
 463         p[3] = 1;
 464
 465         pr_info("use-after-scope on array\n");
 466         {
 467                 char local[1024] = {0};
 468
 469                 p = local;
 470         }
 471         p[0] = 1;
 472         p[1023] = 1;
 473 }
 474
 475 static int __init kmalloc_tests_init(void)
 476 {
 477         kmalloc_oob_right();
 478         kmalloc_oob_left();
 479         kmalloc_node_oob_right();
 480 #ifdef CONFIG_SLUB
 481         kmalloc_pagealloc_oob_right();
 482 #endif
 483         kmalloc_large_oob_right();
 484         kmalloc_oob_krealloc_more();
 485         kmalloc_oob_krealloc_less();
 486         kmalloc_oob_16();
 487         kmalloc_oob_in_memset();
 488         kmalloc_oob_memset_2();
 489         kmalloc_oob_memset_4();
 490         kmalloc_oob_memset_8();
 491         kmalloc_oob_memset_16();
 492         kmalloc_uaf();
 493         kmalloc_uaf_memset();
 494         kmalloc_uaf2();
 495         kmem_cache_oob();
 496         memcg_accounted_kmem_cache();
 497         kasan_stack_oob();
 498         kasan_global_oob();
 499         ksize_unpoisons_memory();
 500         copy_user_test();
 501         use_after_scope_test();
 502         return -EAGAIN;
 503 }
 504
 505 module_init(kmalloc_tests_init);
 506 MODULE_LICENSE("GPL");