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
kmalloc_oob_right(void)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
kmalloc_oob_left(void)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
kmalloc_node_oob_right(void)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
kmalloc_pagealloc_oob_right(void)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
kmalloc_pagealloc_uaf(void)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
kmalloc_pagealloc_invalid_free(void)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
kmalloc_large_oob_right(void)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
kmalloc_oob_krealloc_more(void)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 return;
161 }
162
163 ptr2[size2] = 'x';
164 kfree(ptr2);
165 }
166
kmalloc_oob_krealloc_less(void)167 static noinline void __init kmalloc_oob_krealloc_less(void)
168 {
169 char *ptr1, *ptr2;
170 size_t size1 = 17;
171 size_t size2 = 15;
172
173 pr_info("out-of-bounds after krealloc less\n");
174 ptr1 = kmalloc(size1, GFP_KERNEL);
175 ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
176 if (!ptr1 || !ptr2) {
177 pr_err("Allocation failed\n");
178 kfree(ptr1);
179 return;
180 }
181 ptr2[size2] = 'x';
182 kfree(ptr2);
183 }
184
kmalloc_oob_16(void)185 static noinline void __init kmalloc_oob_16(void)
186 {
187 struct {
188 u64 words[2];
189 } *ptr1, *ptr2;
190
191 pr_info("kmalloc out-of-bounds for 16-bytes access\n");
192 ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
193 ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
194 if (!ptr1 || !ptr2) {
195 pr_err("Allocation failed\n");
196 kfree(ptr1);
197 kfree(ptr2);
198 return;
199 }
200 *ptr1 = *ptr2;
201 kfree(ptr1);
202 kfree(ptr2);
203 }
204
kmalloc_oob_memset_2(void)205 static noinline void __init kmalloc_oob_memset_2(void)
206 {
207 char *ptr;
208 size_t size = 8;
209
210 pr_info("out-of-bounds in memset2\n");
211 ptr = kmalloc(size, GFP_KERNEL);
212 if (!ptr) {
213 pr_err("Allocation failed\n");
214 return;
215 }
216
217 memset(ptr+7, 0, 2);
218 kfree(ptr);
219 }
220
kmalloc_oob_memset_4(void)221 static noinline void __init kmalloc_oob_memset_4(void)
222 {
223 char *ptr;
224 size_t size = 8;
225
226 pr_info("out-of-bounds in memset4\n");
227 ptr = kmalloc(size, GFP_KERNEL);
228 if (!ptr) {
229 pr_err("Allocation failed\n");
230 return;
231 }
232
233 memset(ptr+5, 0, 4);
234 kfree(ptr);
235 }
236
237
kmalloc_oob_memset_8(void)238 static noinline void __init kmalloc_oob_memset_8(void)
239 {
240 char *ptr;
241 size_t size = 8;
242
243 pr_info("out-of-bounds in memset8\n");
244 ptr = kmalloc(size, GFP_KERNEL);
245 if (!ptr) {
246 pr_err("Allocation failed\n");
247 return;
248 }
249
250 memset(ptr+1, 0, 8);
251 kfree(ptr);
252 }
253
kmalloc_oob_memset_16(void)254 static noinline void __init kmalloc_oob_memset_16(void)
255 {
256 char *ptr;
257 size_t size = 16;
258
259 pr_info("out-of-bounds in memset16\n");
260 ptr = kmalloc(size, GFP_KERNEL);
261 if (!ptr) {
262 pr_err("Allocation failed\n");
263 return;
264 }
265
266 memset(ptr+1, 0, 16);
267 kfree(ptr);
268 }
269
kmalloc_oob_in_memset(void)270 static noinline void __init kmalloc_oob_in_memset(void)
271 {
272 char *ptr;
273 size_t size = 666;
274
275 pr_info("out-of-bounds in memset\n");
276 ptr = kmalloc(size, GFP_KERNEL);
277 if (!ptr) {
278 pr_err("Allocation failed\n");
279 return;
280 }
281
282 memset(ptr, 0, size+5);
283 kfree(ptr);
284 }
285
kmalloc_uaf(void)286 static noinline void __init kmalloc_uaf(void)
287 {
288 char *ptr;
289 size_t size = 10;
290
291 pr_info("use-after-free\n");
292 ptr = kmalloc(size, GFP_KERNEL);
293 if (!ptr) {
294 pr_err("Allocation failed\n");
295 return;
296 }
297
298 kfree(ptr);
299 *(ptr + 8) = 'x';
300 }
301
kmalloc_uaf_memset(void)302 static noinline void __init kmalloc_uaf_memset(void)
303 {
304 char *ptr;
305 size_t size = 33;
306
307 pr_info("use-after-free in memset\n");
308 ptr = kmalloc(size, GFP_KERNEL);
309 if (!ptr) {
310 pr_err("Allocation failed\n");
311 return;
312 }
313
314 kfree(ptr);
315 memset(ptr, 0, size);
316 }
317
kmalloc_uaf2(void)318 static noinline void __init kmalloc_uaf2(void)
319 {
320 char *ptr1, *ptr2;
321 size_t size = 43;
322
323 pr_info("use-after-free after another kmalloc\n");
324 ptr1 = kmalloc(size, GFP_KERNEL);
325 if (!ptr1) {
326 pr_err("Allocation failed\n");
327 return;
328 }
329
330 kfree(ptr1);
331 ptr2 = kmalloc(size, GFP_KERNEL);
332 if (!ptr2) {
333 pr_err("Allocation failed\n");
334 return;
335 }
336
337 ptr1[40] = 'x';
338 if (ptr1 == ptr2)
339 pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
340 kfree(ptr2);
341 }
342
kmem_cache_oob(void)343 static noinline void __init kmem_cache_oob(void)
344 {
345 char *p;
346 size_t size = 200;
347 struct kmem_cache *cache = kmem_cache_create("test_cache",
348 size, 0,
349 0, NULL);
350 if (!cache) {
351 pr_err("Cache allocation failed\n");
352 return;
353 }
354 pr_info("out-of-bounds in kmem_cache_alloc\n");
355 p = kmem_cache_alloc(cache, GFP_KERNEL);
356 if (!p) {
357 pr_err("Allocation failed\n");
358 kmem_cache_destroy(cache);
359 return;
360 }
361
362 *p = p[size];
363 kmem_cache_free(cache, p);
364 kmem_cache_destroy(cache);
365 }
366
memcg_accounted_kmem_cache(void)367 static noinline void __init memcg_accounted_kmem_cache(void)
368 {
369 int i;
370 char *p;
371 size_t size = 200;
372 struct kmem_cache *cache;
373
374 cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
375 if (!cache) {
376 pr_err("Cache allocation failed\n");
377 return;
378 }
379
380 pr_info("allocate memcg accounted object\n");
381 /*
382 * Several allocations with a delay to allow for lazy per memcg kmem
383 * cache creation.
384 */
385 for (i = 0; i < 5; i++) {
386 p = kmem_cache_alloc(cache, GFP_KERNEL);
387 if (!p)
388 goto free_cache;
389
390 kmem_cache_free(cache, p);
391 msleep(100);
392 }
393
394 free_cache:
395 kmem_cache_destroy(cache);
396 }
397
398 static char global_array[10];
399
kasan_global_oob(void)400 static noinline void __init kasan_global_oob(void)
401 {
402 volatile int i = 3;
403 char *p = &global_array[ARRAY_SIZE(global_array) + i];
404
405 pr_info("out-of-bounds global variable\n");
406 *(volatile char *)p;
407 }
408
kasan_stack_oob(void)409 static noinline void __init kasan_stack_oob(void)
410 {
411 char stack_array[10];
412 volatile int i = 0;
413 char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
414
415 pr_info("out-of-bounds on stack\n");
416 *(volatile char *)p;
417 }
418
ksize_unpoisons_memory(void)419 static noinline void __init ksize_unpoisons_memory(void)
420 {
421 char *ptr;
422 size_t size = 123, real_size;
423
424 pr_info("ksize() unpoisons the whole allocated chunk\n");
425 ptr = kmalloc(size, GFP_KERNEL);
426 if (!ptr) {
427 pr_err("Allocation failed\n");
428 return;
429 }
430 real_size = ksize(ptr);
431 /* This access doesn't trigger an error. */
432 ptr[size] = 'x';
433 /* This one does. */
434 ptr[real_size] = 'y';
435 kfree(ptr);
436 }
437
copy_user_test(void)438 static noinline void __init copy_user_test(void)
439 {
440 char *kmem;
441 char __user *usermem;
442 size_t size = 10;
443 int unused;
444
445 kmem = kmalloc(size, GFP_KERNEL);
446 if (!kmem)
447 return;
448
449 usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
450 PROT_READ | PROT_WRITE | PROT_EXEC,
451 MAP_ANONYMOUS | MAP_PRIVATE, 0);
452 if (IS_ERR(usermem)) {
453 pr_err("Failed to allocate user memory\n");
454 kfree(kmem);
455 return;
456 }
457
458 pr_info("out-of-bounds in copy_from_user()\n");
459 unused = copy_from_user(kmem, usermem, size + 1);
460
461 pr_info("out-of-bounds in copy_to_user()\n");
462 unused = copy_to_user(usermem, kmem, size + 1);
463
464 pr_info("out-of-bounds in __copy_from_user()\n");
465 unused = __copy_from_user(kmem, usermem, size + 1);
466
467 pr_info("out-of-bounds in __copy_to_user()\n");
468 unused = __copy_to_user(usermem, kmem, size + 1);
469
470 pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
471 unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
472
473 pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
474 unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
475
476 pr_info("out-of-bounds in strncpy_from_user()\n");
477 unused = strncpy_from_user(kmem, usermem, size + 1);
478
479 vm_munmap((unsigned long)usermem, PAGE_SIZE);
480 kfree(kmem);
481 }
482
use_after_scope_test(void)483 static noinline void __init use_after_scope_test(void)
484 {
485 volatile char *volatile p;
486
487 pr_info("use-after-scope on int\n");
488 {
489 int local = 0;
490
491 p = (char *)&local;
492 }
493 p[0] = 1;
494 p[3] = 1;
495
496 pr_info("use-after-scope on array\n");
497 {
498 char local[1024] = {0};
499
500 p = local;
501 }
502 p[0] = 1;
503 p[1023] = 1;
504 }
505
kasan_alloca_oob_left(void)506 static noinline void __init kasan_alloca_oob_left(void)
507 {
508 volatile int i = 10;
509 char alloca_array[i];
510 char *p = alloca_array - 1;
511
512 pr_info("out-of-bounds to left on alloca\n");
513 *(volatile char *)p;
514 }
515
kasan_alloca_oob_right(void)516 static noinline void __init kasan_alloca_oob_right(void)
517 {
518 volatile int i = 10;
519 char alloca_array[i];
520 char *p = alloca_array + i;
521
522 pr_info("out-of-bounds to right on alloca\n");
523 *(volatile char *)p;
524 }
525
kmem_cache_double_free(void)526 static noinline void __init kmem_cache_double_free(void)
527 {
528 char *p;
529 size_t size = 200;
530 struct kmem_cache *cache;
531
532 cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
533 if (!cache) {
534 pr_err("Cache allocation failed\n");
535 return;
536 }
537 pr_info("double-free on heap object\n");
538 p = kmem_cache_alloc(cache, GFP_KERNEL);
539 if (!p) {
540 pr_err("Allocation failed\n");
541 kmem_cache_destroy(cache);
542 return;
543 }
544
545 kmem_cache_free(cache, p);
546 kmem_cache_free(cache, p);
547 kmem_cache_destroy(cache);
548 }
549
kmem_cache_invalid_free(void)550 static noinline void __init kmem_cache_invalid_free(void)
551 {
552 char *p;
553 size_t size = 200;
554 struct kmem_cache *cache;
555
556 cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
557 NULL);
558 if (!cache) {
559 pr_err("Cache allocation failed\n");
560 return;
561 }
562 pr_info("invalid-free of heap object\n");
563 p = kmem_cache_alloc(cache, GFP_KERNEL);
564 if (!p) {
565 pr_err("Allocation failed\n");
566 kmem_cache_destroy(cache);
567 return;
568 }
569
570 /* Trigger invalid free, the object doesn't get freed */
571 kmem_cache_free(cache, p + 1);
572
573 /*
574 * Properly free the object to prevent the "Objects remaining in
575 * test_cache on __kmem_cache_shutdown" BUG failure.
576 */
577 kmem_cache_free(cache, p);
578
579 kmem_cache_destroy(cache);
580 }
581
kmalloc_tests_init(void)582 static int __init kmalloc_tests_init(void)
583 {
584 /*
585 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
586 * report for the first case.
587 */
588 bool multishot = kasan_save_enable_multi_shot();
589
590 kmalloc_oob_right();
591 kmalloc_oob_left();
592 kmalloc_node_oob_right();
593 #ifdef CONFIG_SLUB
594 kmalloc_pagealloc_oob_right();
595 kmalloc_pagealloc_uaf();
596 kmalloc_pagealloc_invalid_free();
597 #endif
598 kmalloc_large_oob_right();
599 kmalloc_oob_krealloc_more();
600 kmalloc_oob_krealloc_less();
601 kmalloc_oob_16();
602 kmalloc_oob_in_memset();
603 kmalloc_oob_memset_2();
604 kmalloc_oob_memset_4();
605 kmalloc_oob_memset_8();
606 kmalloc_oob_memset_16();
607 kmalloc_uaf();
608 kmalloc_uaf_memset();
609 kmalloc_uaf2();
610 kmem_cache_oob();
611 memcg_accounted_kmem_cache();
612 kasan_stack_oob();
613 kasan_global_oob();
614 kasan_alloca_oob_left();
615 kasan_alloca_oob_right();
616 ksize_unpoisons_memory();
617 copy_user_test();
618 use_after_scope_test();
619 kmem_cache_double_free();
620 kmem_cache_invalid_free();
621
622 kasan_restore_multi_shot(multishot);
623
624 return -EAGAIN;
625 }
626
627 module_init(kmalloc_tests_init);
628 MODULE_LICENSE("GPL");
629
