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/kernel.h>
  15 #include <linux/printk.h>
  16 #include <linux/slab.h>
  17 #include <linux/string.h>
  18 #include <linux/module.h>
  19
  20 static noinline void __init kmalloc_oob_right(void)
  21 {
  22         char *ptr;
  23         size_t size = 123;
  24
  25         pr_info("out-of-bounds to right\n");
  26         ptr = kmalloc(size, GFP_KERNEL);
  27         if (!ptr) {
  28                 pr_err("Allocation failed\n");
  29                 return;
  30         }
  31
  32         ptr[size] = 'x';
  33         kfree(ptr);
  34 }
  35
  36 static noinline void __init kmalloc_oob_left(void)
  37 {
  38         char *ptr;
  39         size_t size = 15;
  40
  41         pr_info("out-of-bounds to left\n");
  42         ptr = kmalloc(size, GFP_KERNEL);
  43         if (!ptr) {
  44                 pr_err("Allocation failed\n");
  45                 return;
  46         }
  47
  48         *ptr = *(ptr - 1);
  49         kfree(ptr);
  50 }
  51
  52 static noinline void __init kmalloc_node_oob_right(void)
  53 {
  54         char *ptr;
  55         size_t size = 4096;
  56
  57         pr_info("kmalloc_node(): out-of-bounds to right\n");
  58         ptr = kmalloc_node(size, GFP_KERNEL, 0);
  59         if (!ptr) {
  60                 pr_err("Allocation failed\n");
  61                 return;
  62         }
  63
  64         ptr[size] = 0;
  65         kfree(ptr);
  66 }
  67
  68 #ifdef CONFIG_SLUB
  69 static noinline void __init kmalloc_pagealloc_oob_right(void)
  70 {
  71         char *ptr;
  72         size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
  73
  74         /* Allocate a chunk that does not fit into a SLUB cache to trigger
  75          * the page allocator fallback.
  76          */
  77         pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
  78         ptr = kmalloc(size, GFP_KERNEL);
  79         if (!ptr) {
  80                 pr_err("Allocation failed\n");
  81                 return;
  82         }
  83
  84         ptr[size] = 0;
  85         kfree(ptr);
  86 }
  87 #endif
  88
  89 static noinline void __init kmalloc_large_oob_right(void)
  90 {
  91         char *ptr;
  92         size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
  93         /* Allocate a chunk that is large enough, but still fits into a slab
  94          * and does not trigger the page allocator fallback in SLUB.
  95          */
  96         pr_info("kmalloc large allocation: out-of-bounds to right\n");
  97         ptr = kmalloc(size, GFP_KERNEL);
  98         if (!ptr) {
  99                 pr_err("Allocation failed\n");
 100                 return;
 101         }
 102
 103         ptr[size] = 0;
 104         kfree(ptr);
 105 }
 106
 107 static noinline void __init kmalloc_oob_krealloc_more(void)
 108 {
 109         char *ptr1, *ptr2;
 110         size_t size1 = 17;
 111         size_t size2 = 19;
 112
 113         pr_info("out-of-bounds after krealloc more\n");
 114         ptr1 = kmalloc(size1, GFP_KERNEL);
 115         ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
 116         if (!ptr1 || !ptr2) {
 117                 pr_err("Allocation failed\n");
 118                 kfree(ptr1);
 119                 return;
 120         }
 121
 122         ptr2[size2] = 'x';
 123         kfree(ptr2);
 124 }
 125
 126 static noinline void __init kmalloc_oob_krealloc_less(void)
 127 {
 128         char *ptr1, *ptr2;
 129         size_t size1 = 17;
 130         size_t size2 = 15;
 131
 132         pr_info("out-of-bounds after krealloc less\n");
 133         ptr1 = kmalloc(size1, GFP_KERNEL);
 134         ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
 135         if (!ptr1 || !ptr2) {
 136                 pr_err("Allocation failed\n");
 137                 kfree(ptr1);
 138                 return;
 139         }
 140         ptr2[size2] = 'x';
 141         kfree(ptr2);
 142 }
 143
 144 static noinline void __init kmalloc_oob_16(void)
 145 {
 146         struct {
 147                 u64 words[2];
 148         } *ptr1, *ptr2;
 149
 150         pr_info("kmalloc out-of-bounds for 16-bytes access\n");
 151         ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
 152         ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
 153         if (!ptr1 || !ptr2) {
 154                 pr_err("Allocation failed\n");
 155                 kfree(ptr1);
 156                 kfree(ptr2);
 157                 return;
 158         }
 159         *ptr1 = *ptr2;
 160         kfree(ptr1);
 161         kfree(ptr2);
 162 }
 163
 164 static noinline void __init kmalloc_oob_memset_2(void)
 165 {
 166         char *ptr;
 167         size_t size = 8;
 168
 169         pr_info("out-of-bounds in memset2\n");
 170         ptr = kmalloc(size, GFP_KERNEL);
 171         if (!ptr) {
 172                 pr_err("Allocation failed\n");
 173                 return;
 174         }
 175
 176         memset(ptr+7, 0, 2);
 177         kfree(ptr);
 178 }
 179
 180 static noinline void __init kmalloc_oob_memset_4(void)
 181 {
 182         char *ptr;
 183         size_t size = 8;
 184
 185         pr_info("out-of-bounds in memset4\n");
 186         ptr = kmalloc(size, GFP_KERNEL);
 187         if (!ptr) {
 188                 pr_err("Allocation failed\n");
 189                 return;
 190         }
 191
 192         memset(ptr+5, 0, 4);
 193         kfree(ptr);
 194 }
 195
 196
 197 static noinline void __init kmalloc_oob_memset_8(void)
 198 {
 199         char *ptr;
 200         size_t size = 8;
 201
 202         pr_info("out-of-bounds in memset8\n");
 203         ptr = kmalloc(size, GFP_KERNEL);
 204         if (!ptr) {
 205                 pr_err("Allocation failed\n");
 206                 return;
 207         }
 208
 209         memset(ptr+1, 0, 8);
 210         kfree(ptr);
 211 }
 212
 213 static noinline void __init kmalloc_oob_memset_16(void)
 214 {
 215         char *ptr;
 216         size_t size = 16;
 217
 218         pr_info("out-of-bounds in memset16\n");
 219         ptr = kmalloc(size, GFP_KERNEL);
 220         if (!ptr) {
 221                 pr_err("Allocation failed\n");
 222                 return;
 223         }
 224
 225         memset(ptr+1, 0, 16);
 226         kfree(ptr);
 227 }
 228
 229 static noinline void __init kmalloc_oob_in_memset(void)
 230 {
 231         char *ptr;
 232         size_t size = 666;
 233
 234         pr_info("out-of-bounds in memset\n");
 235         ptr = kmalloc(size, GFP_KERNEL);
 236         if (!ptr) {
 237                 pr_err("Allocation failed\n");
 238                 return;
 239         }
 240
 241         memset(ptr, 0, size+5);
 242         kfree(ptr);
 243 }
 244
 245 static noinline void __init kmalloc_uaf(void)
 246 {
 247         char *ptr;
 248         size_t size = 10;
 249
 250         pr_info("use-after-free\n");
 251         ptr = kmalloc(size, GFP_KERNEL);
 252         if (!ptr) {
 253                 pr_err("Allocation failed\n");
 254                 return;
 255         }
 256
 257         kfree(ptr);
 258         *(ptr + 8) = 'x';
 259 }
 260
 261 static noinline void __init kmalloc_uaf_memset(void)
 262 {
 263         char *ptr;
 264         size_t size = 33;
 265
 266         pr_info("use-after-free in memset\n");
 267         ptr = kmalloc(size, GFP_KERNEL);
 268         if (!ptr) {
 269                 pr_err("Allocation failed\n");
 270                 return;
 271         }
 272
 273         kfree(ptr);
 274         memset(ptr, 0, size);
 275 }
 276
 277 static noinline void __init kmalloc_uaf2(void)
 278 {
 279         char *ptr1, *ptr2;
 280         size_t size = 43;
 281
 282         pr_info("use-after-free after another kmalloc\n");
 283         ptr1 = kmalloc(size, GFP_KERNEL);
 284         if (!ptr1) {
 285                 pr_err("Allocation failed\n");
 286                 return;
 287         }
 288
 289         kfree(ptr1);
 290         ptr2 = kmalloc(size, GFP_KERNEL);
 291         if (!ptr2) {
 292                 pr_err("Allocation failed\n");
 293                 return;
 294         }
 295
 296         ptr1[40] = 'x';
 297         if (ptr1 == ptr2)
 298                 pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
 299         kfree(ptr2);
 300 }
 301
 302 static noinline void __init kmem_cache_oob(void)
 303 {
 304         char *p;
 305         size_t size = 200;
 306         struct kmem_cache *cache = kmem_cache_create("test_cache",
 307                                                 size, 0,
 308                                                 0, NULL);
 309         if (!cache) {
 310                 pr_err("Cache allocation failed\n");
 311                 return;
 312         }
 313         pr_info("out-of-bounds in kmem_cache_alloc\n");
 314         p = kmem_cache_alloc(cache, GFP_KERNEL);
 315         if (!p) {
 316                 pr_err("Allocation failed\n");
 317                 kmem_cache_destroy(cache);
 318                 return;
 319         }
 320
 321         *p = p[size];
 322         kmem_cache_free(cache, p);
 323         kmem_cache_destroy(cache);
 324 }
 325
 326 static char global_array[10];
 327
 328 static noinline void __init kasan_global_oob(void)
 329 {
 330         volatile int i = 3;
 331         char *p = &global_array[ARRAY_SIZE(global_array) + i];
 332
 333         pr_info("out-of-bounds global variable\n");
 334         *(volatile char *)p;
 335 }
 336
 337 static noinline void __init kasan_stack_oob(void)
 338 {
 339         char stack_array[10];
 340         volatile int i = 0;
 341         char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
 342
 343         pr_info("out-of-bounds on stack\n");
 344         *(volatile char *)p;
 345 }
 346
 347 static int __init kmalloc_tests_init(void)
 348 {
 349         kmalloc_oob_right();
 350         kmalloc_oob_left();
 351         kmalloc_node_oob_right();
 352 #ifdef CONFIG_SLUB
 353         kmalloc_pagealloc_oob_right();
 354 #endif
 355         kmalloc_large_oob_right();
 356         kmalloc_oob_krealloc_more();
 357         kmalloc_oob_krealloc_less();
 358         kmalloc_oob_16();
 359         kmalloc_oob_in_memset();
 360         kmalloc_oob_memset_2();
 361         kmalloc_oob_memset_4();
 362         kmalloc_oob_memset_8();
 363         kmalloc_oob_memset_16();
 364         kmalloc_uaf();
 365         kmalloc_uaf_memset();
 366         kmalloc_uaf2();
 367         kmem_cache_oob();
 368         kasan_stack_oob();
 369         kasan_global_oob();
 370         return -EAGAIN;
 371 }
 372
 373 module_init(kmalloc_tests_init);
 374 MODULE_LICENSE("GPL");