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d2912cb1 1// SPDX-License-Identifier: GPL-2.0-only
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2/*
3 *
4 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
5 * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
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6 */
7
8#define pr_fmt(fmt) "kasan test: %s " fmt, __func__
9
0386bf38 10#include <linux/delay.h>
3f15801c 11#include <linux/kernel.h>
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12#include <linux/mman.h>
13#include <linux/mm.h>
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14#include <linux/printk.h>
15#include <linux/slab.h>
16#include <linux/string.h>
eae08dca 17#include <linux/uaccess.h>
3f15801c 18#include <linux/module.h>
b0845ce5 19#include <linux/kasan.h>
3f15801c 20
828347f8
DV
21/*
22 * Note: test functions are marked noinline so that their names appear in
23 * reports.
24 */
25
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AR
26static noinline void __init kmalloc_oob_right(void)
27{
28 char *ptr;
29 size_t size = 123;
30
31 pr_info("out-of-bounds to right\n");
32 ptr = kmalloc(size, GFP_KERNEL);
33 if (!ptr) {
34 pr_err("Allocation failed\n");
35 return;
36 }
37
38 ptr[size] = 'x';
39 kfree(ptr);
40}
41
42static noinline void __init kmalloc_oob_left(void)
43{
44 char *ptr;
45 size_t size = 15;
46
47 pr_info("out-of-bounds to left\n");
48 ptr = kmalloc(size, GFP_KERNEL);
49 if (!ptr) {
50 pr_err("Allocation failed\n");
51 return;
52 }
53
54 *ptr = *(ptr - 1);
55 kfree(ptr);
56}
57
58static noinline void __init kmalloc_node_oob_right(void)
59{
60 char *ptr;
61 size_t size = 4096;
62
63 pr_info("kmalloc_node(): out-of-bounds to right\n");
64 ptr = kmalloc_node(size, GFP_KERNEL, 0);
65 if (!ptr) {
66 pr_err("Allocation failed\n");
67 return;
68 }
69
70 ptr[size] = 0;
71 kfree(ptr);
72}
73
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AP
74#ifdef CONFIG_SLUB
75static noinline void __init kmalloc_pagealloc_oob_right(void)
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AR
76{
77 char *ptr;
78 size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
79
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AP
80 /* Allocate a chunk that does not fit into a SLUB cache to trigger
81 * the page allocator fallback.
82 */
83 pr_info("kmalloc pagealloc allocation: out-of-bounds to right\n");
84 ptr = kmalloc(size, GFP_KERNEL);
85 if (!ptr) {
86 pr_err("Allocation failed\n");
87 return;
88 }
89
90 ptr[size] = 0;
91 kfree(ptr);
92}
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DV
93
94static noinline void __init kmalloc_pagealloc_uaf(void)
95{
96 char *ptr;
97 size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
98
99 pr_info("kmalloc pagealloc allocation: use-after-free\n");
100 ptr = kmalloc(size, GFP_KERNEL);
101 if (!ptr) {
102 pr_err("Allocation failed\n");
103 return;
104 }
105
106 kfree(ptr);
107 ptr[0] = 0;
108}
109
110static noinline void __init kmalloc_pagealloc_invalid_free(void)
111{
112 char *ptr;
113 size_t size = KMALLOC_MAX_CACHE_SIZE + 10;
114
115 pr_info("kmalloc pagealloc allocation: invalid-free\n");
116 ptr = kmalloc(size, GFP_KERNEL);
117 if (!ptr) {
118 pr_err("Allocation failed\n");
119 return;
120 }
121
122 kfree(ptr + 1);
123}
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AP
124#endif
125
126static noinline void __init kmalloc_large_oob_right(void)
127{
128 char *ptr;
129 size_t size = KMALLOC_MAX_CACHE_SIZE - 256;
130 /* Allocate a chunk that is large enough, but still fits into a slab
131 * and does not trigger the page allocator fallback in SLUB.
132 */
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133 pr_info("kmalloc large allocation: out-of-bounds to right\n");
134 ptr = kmalloc(size, GFP_KERNEL);
135 if (!ptr) {
136 pr_err("Allocation failed\n");
137 return;
138 }
139
140 ptr[size] = 0;
141 kfree(ptr);
142}
143
144static noinline void __init kmalloc_oob_krealloc_more(void)
145{
146 char *ptr1, *ptr2;
147 size_t size1 = 17;
148 size_t size2 = 19;
149
150 pr_info("out-of-bounds after krealloc more\n");
151 ptr1 = kmalloc(size1, GFP_KERNEL);
152 ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
153 if (!ptr1 || !ptr2) {
154 pr_err("Allocation failed\n");
155 kfree(ptr1);
156 return;
157 }
158
159 ptr2[size2] = 'x';
160 kfree(ptr2);
161}
162
163static noinline void __init kmalloc_oob_krealloc_less(void)
164{
165 char *ptr1, *ptr2;
166 size_t size1 = 17;
167 size_t size2 = 15;
168
169 pr_info("out-of-bounds after krealloc less\n");
170 ptr1 = kmalloc(size1, GFP_KERNEL);
171 ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
172 if (!ptr1 || !ptr2) {
173 pr_err("Allocation failed\n");
174 kfree(ptr1);
175 return;
176 }
6b4a35fc 177 ptr2[size2] = 'x';
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178 kfree(ptr2);
179}
180
181static noinline void __init kmalloc_oob_16(void)
182{
183 struct {
184 u64 words[2];
185 } *ptr1, *ptr2;
186
187 pr_info("kmalloc out-of-bounds for 16-bytes access\n");
188 ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
189 ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
190 if (!ptr1 || !ptr2) {
191 pr_err("Allocation failed\n");
192 kfree(ptr1);
193 kfree(ptr2);
194 return;
195 }
196 *ptr1 = *ptr2;
197 kfree(ptr1);
198 kfree(ptr2);
199}
200
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201static noinline void __init kmalloc_oob_memset_2(void)
202{
203 char *ptr;
204 size_t size = 8;
205
206 pr_info("out-of-bounds in memset2\n");
207 ptr = kmalloc(size, GFP_KERNEL);
208 if (!ptr) {
209 pr_err("Allocation failed\n");
210 return;
211 }
212
213 memset(ptr+7, 0, 2);
214 kfree(ptr);
215}
216
217static noinline void __init kmalloc_oob_memset_4(void)
218{
219 char *ptr;
220 size_t size = 8;
221
222 pr_info("out-of-bounds in memset4\n");
223 ptr = kmalloc(size, GFP_KERNEL);
224 if (!ptr) {
225 pr_err("Allocation failed\n");
226 return;
227 }
228
229 memset(ptr+5, 0, 4);
230 kfree(ptr);
231}
232
233
234static noinline void __init kmalloc_oob_memset_8(void)
235{
236 char *ptr;
237 size_t size = 8;
238
239 pr_info("out-of-bounds in memset8\n");
240 ptr = kmalloc(size, GFP_KERNEL);
241 if (!ptr) {
242 pr_err("Allocation failed\n");
243 return;
244 }
245
246 memset(ptr+1, 0, 8);
247 kfree(ptr);
248}
249
250static noinline void __init kmalloc_oob_memset_16(void)
251{
252 char *ptr;
253 size_t size = 16;
254
255 pr_info("out-of-bounds in memset16\n");
256 ptr = kmalloc(size, GFP_KERNEL);
257 if (!ptr) {
258 pr_err("Allocation failed\n");
259 return;
260 }
261
262 memset(ptr+1, 0, 16);
263 kfree(ptr);
264}
265
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266static noinline void __init kmalloc_oob_in_memset(void)
267{
268 char *ptr;
269 size_t size = 666;
270
271 pr_info("out-of-bounds in memset\n");
272 ptr = kmalloc(size, GFP_KERNEL);
273 if (!ptr) {
274 pr_err("Allocation failed\n");
275 return;
276 }
277
278 memset(ptr, 0, size+5);
279 kfree(ptr);
280}
281
282static noinline void __init kmalloc_uaf(void)
283{
284 char *ptr;
285 size_t size = 10;
286
287 pr_info("use-after-free\n");
288 ptr = kmalloc(size, GFP_KERNEL);
289 if (!ptr) {
290 pr_err("Allocation failed\n");
291 return;
292 }
293
294 kfree(ptr);
295 *(ptr + 8) = 'x';
296}
297
298static noinline void __init kmalloc_uaf_memset(void)
299{
300 char *ptr;
301 size_t size = 33;
302
303 pr_info("use-after-free in memset\n");
304 ptr = kmalloc(size, GFP_KERNEL);
305 if (!ptr) {
306 pr_err("Allocation failed\n");
307 return;
308 }
309
310 kfree(ptr);
311 memset(ptr, 0, size);
312}
313
314static noinline void __init kmalloc_uaf2(void)
315{
316 char *ptr1, *ptr2;
317 size_t size = 43;
318
319 pr_info("use-after-free after another kmalloc\n");
320 ptr1 = kmalloc(size, GFP_KERNEL);
321 if (!ptr1) {
322 pr_err("Allocation failed\n");
323 return;
324 }
325
326 kfree(ptr1);
327 ptr2 = kmalloc(size, GFP_KERNEL);
328 if (!ptr2) {
329 pr_err("Allocation failed\n");
330 return;
331 }
332
333 ptr1[40] = 'x';
9dcadd38
AP
334 if (ptr1 == ptr2)
335 pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
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336 kfree(ptr2);
337}
338
339static noinline void __init kmem_cache_oob(void)
340{
341 char *p;
342 size_t size = 200;
343 struct kmem_cache *cache = kmem_cache_create("test_cache",
344 size, 0,
345 0, NULL);
346 if (!cache) {
347 pr_err("Cache allocation failed\n");
348 return;
349 }
350 pr_info("out-of-bounds in kmem_cache_alloc\n");
351 p = kmem_cache_alloc(cache, GFP_KERNEL);
352 if (!p) {
353 pr_err("Allocation failed\n");
354 kmem_cache_destroy(cache);
355 return;
356 }
357
358 *p = p[size];
359 kmem_cache_free(cache, p);
360 kmem_cache_destroy(cache);
361}
362
0386bf38
GT
363static noinline void __init memcg_accounted_kmem_cache(void)
364{
365 int i;
366 char *p;
367 size_t size = 200;
368 struct kmem_cache *cache;
369
370 cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
371 if (!cache) {
372 pr_err("Cache allocation failed\n");
373 return;
374 }
375
376 pr_info("allocate memcg accounted object\n");
377 /*
378 * Several allocations with a delay to allow for lazy per memcg kmem
379 * cache creation.
380 */
381 for (i = 0; i < 5; i++) {
382 p = kmem_cache_alloc(cache, GFP_KERNEL);
dc2bf000 383 if (!p)
0386bf38 384 goto free_cache;
dc2bf000 385
0386bf38
GT
386 kmem_cache_free(cache, p);
387 msleep(100);
388 }
389
390free_cache:
391 kmem_cache_destroy(cache);
392}
393
3f15801c
AR
394static char global_array[10];
395
396static noinline void __init kasan_global_oob(void)
397{
398 volatile int i = 3;
399 char *p = &global_array[ARRAY_SIZE(global_array) + i];
400
401 pr_info("out-of-bounds global variable\n");
402 *(volatile char *)p;
403}
404
405static noinline void __init kasan_stack_oob(void)
406{
407 char stack_array[10];
408 volatile int i = 0;
409 char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
410
411 pr_info("out-of-bounds on stack\n");
412 *(volatile char *)p;
413}
414
96fe805f
AP
415static noinline void __init ksize_unpoisons_memory(void)
416{
417 char *ptr;
48c23239 418 size_t size = 123, real_size;
96fe805f
AP
419
420 pr_info("ksize() unpoisons the whole allocated chunk\n");
421 ptr = kmalloc(size, GFP_KERNEL);
422 if (!ptr) {
423 pr_err("Allocation failed\n");
424 return;
425 }
426 real_size = ksize(ptr);
427 /* This access doesn't trigger an error. */
428 ptr[size] = 'x';
429 /* This one does. */
430 ptr[real_size] = 'y';
431 kfree(ptr);
432}
433
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AR
434static noinline void __init copy_user_test(void)
435{
436 char *kmem;
437 char __user *usermem;
438 size_t size = 10;
439 int unused;
440
441 kmem = kmalloc(size, GFP_KERNEL);
442 if (!kmem)
443 return;
444
445 usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
446 PROT_READ | PROT_WRITE | PROT_EXEC,
447 MAP_ANONYMOUS | MAP_PRIVATE, 0);
448 if (IS_ERR(usermem)) {
449 pr_err("Failed to allocate user memory\n");
450 kfree(kmem);
451 return;
452 }
453
454 pr_info("out-of-bounds in copy_from_user()\n");
455 unused = copy_from_user(kmem, usermem, size + 1);
456
457 pr_info("out-of-bounds in copy_to_user()\n");
458 unused = copy_to_user(usermem, kmem, size + 1);
459
460 pr_info("out-of-bounds in __copy_from_user()\n");
461 unused = __copy_from_user(kmem, usermem, size + 1);
462
463 pr_info("out-of-bounds in __copy_to_user()\n");
464 unused = __copy_to_user(usermem, kmem, size + 1);
465
466 pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
467 unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
468
469 pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
470 unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
471
472 pr_info("out-of-bounds in strncpy_from_user()\n");
473 unused = strncpy_from_user(kmem, usermem, size + 1);
474
475 vm_munmap((unsigned long)usermem, PAGE_SIZE);
476 kfree(kmem);
477}
478
00a14294
PL
479static noinline void __init kasan_alloca_oob_left(void)
480{
481 volatile int i = 10;
482 char alloca_array[i];
483 char *p = alloca_array - 1;
484
485 pr_info("out-of-bounds to left on alloca\n");
486 *(volatile char *)p;
487}
488
489static noinline void __init kasan_alloca_oob_right(void)
490{
491 volatile int i = 10;
492 char alloca_array[i];
493 char *p = alloca_array + i;
494
495 pr_info("out-of-bounds to right on alloca\n");
496 *(volatile char *)p;
497}
498
b1d57289
DV
499static noinline void __init kmem_cache_double_free(void)
500{
501 char *p;
502 size_t size = 200;
503 struct kmem_cache *cache;
504
505 cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
506 if (!cache) {
507 pr_err("Cache allocation failed\n");
508 return;
509 }
510 pr_info("double-free on heap object\n");
511 p = kmem_cache_alloc(cache, GFP_KERNEL);
512 if (!p) {
513 pr_err("Allocation failed\n");
514 kmem_cache_destroy(cache);
515 return;
516 }
517
518 kmem_cache_free(cache, p);
519 kmem_cache_free(cache, p);
520 kmem_cache_destroy(cache);
521}
522
523static noinline void __init kmem_cache_invalid_free(void)
524{
525 char *p;
526 size_t size = 200;
527 struct kmem_cache *cache;
528
529 cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
530 NULL);
531 if (!cache) {
532 pr_err("Cache allocation failed\n");
533 return;
534 }
535 pr_info("invalid-free of heap object\n");
536 p = kmem_cache_alloc(cache, GFP_KERNEL);
537 if (!p) {
538 pr_err("Allocation failed\n");
539 kmem_cache_destroy(cache);
540 return;
541 }
542
91c93ed0 543 /* Trigger invalid free, the object doesn't get freed */
b1d57289 544 kmem_cache_free(cache, p + 1);
91c93ed0
AK
545
546 /*
547 * Properly free the object to prevent the "Objects remaining in
548 * test_cache on __kmem_cache_shutdown" BUG failure.
549 */
550 kmem_cache_free(cache, p);
551
b1d57289
DV
552 kmem_cache_destroy(cache);
553}
554
0c96350a
AR
555static noinline void __init kasan_memchr(void)
556{
557 char *ptr;
558 size_t size = 24;
559
560 pr_info("out-of-bounds in memchr\n");
561 ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
562 if (!ptr)
563 return;
564
565 memchr(ptr, '1', size + 1);
566 kfree(ptr);
567}
568
569static noinline void __init kasan_memcmp(void)
570{
571 char *ptr;
572 size_t size = 24;
573 int arr[9];
574
575 pr_info("out-of-bounds in memcmp\n");
576 ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
577 if (!ptr)
578 return;
579
580 memset(arr, 0, sizeof(arr));
581 memcmp(ptr, arr, size+1);
582 kfree(ptr);
583}
584
585static noinline void __init kasan_strings(void)
586{
587 char *ptr;
588 size_t size = 24;
589
590 pr_info("use-after-free in strchr\n");
591 ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
592 if (!ptr)
593 return;
594
595 kfree(ptr);
596
597 /*
598 * Try to cause only 1 invalid access (less spam in dmesg).
599 * For that we need ptr to point to zeroed byte.
600 * Skip metadata that could be stored in freed object so ptr
601 * will likely point to zeroed byte.
602 */
603 ptr += 16;
604 strchr(ptr, '1');
605
606 pr_info("use-after-free in strrchr\n");
607 strrchr(ptr, '1');
608
609 pr_info("use-after-free in strcmp\n");
610 strcmp(ptr, "2");
611
612 pr_info("use-after-free in strncmp\n");
613 strncmp(ptr, "2", 1);
614
615 pr_info("use-after-free in strlen\n");
616 strlen(ptr);
617
618 pr_info("use-after-free in strnlen\n");
619 strnlen(ptr, 1);
620}
621
3f15801c
AR
622static int __init kmalloc_tests_init(void)
623{
b0845ce5
MR
624 /*
625 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
626 * report for the first case.
627 */
628 bool multishot = kasan_save_enable_multi_shot();
629
3f15801c
AR
630 kmalloc_oob_right();
631 kmalloc_oob_left();
632 kmalloc_node_oob_right();
e6e8379c
AP
633#ifdef CONFIG_SLUB
634 kmalloc_pagealloc_oob_right();
47adccce
DV
635 kmalloc_pagealloc_uaf();
636 kmalloc_pagealloc_invalid_free();
e6e8379c 637#endif
9789d8e0 638 kmalloc_large_oob_right();
3f15801c
AR
639 kmalloc_oob_krealloc_more();
640 kmalloc_oob_krealloc_less();
641 kmalloc_oob_16();
642 kmalloc_oob_in_memset();
f523e737
WL
643 kmalloc_oob_memset_2();
644 kmalloc_oob_memset_4();
645 kmalloc_oob_memset_8();
646 kmalloc_oob_memset_16();
3f15801c
AR
647 kmalloc_uaf();
648 kmalloc_uaf_memset();
649 kmalloc_uaf2();
650 kmem_cache_oob();
0386bf38 651 memcg_accounted_kmem_cache();
3f15801c
AR
652 kasan_stack_oob();
653 kasan_global_oob();
00a14294
PL
654 kasan_alloca_oob_left();
655 kasan_alloca_oob_right();
96fe805f 656 ksize_unpoisons_memory();
eae08dca 657 copy_user_test();
b1d57289
DV
658 kmem_cache_double_free();
659 kmem_cache_invalid_free();
0c96350a
AR
660 kasan_memchr();
661 kasan_memcmp();
662 kasan_strings();
b0845ce5
MR
663
664 kasan_restore_multi_shot(multishot);
665
3f15801c
AR
666 return -EAGAIN;
667}
668
669module_init(kmalloc_tests_init);
670MODULE_LICENSE("GPL");