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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *
4 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
5 * Author: Andrey Ryabinin <a.ryabinin@samsung.com>
6 */
7
8#define pr_fmt(fmt) "kasan test: %s " fmt, __func__
9
10#include <linux/bitops.h>
11#include <linux/delay.h>
12#include <linux/kasan.h>
13#include <linux/kernel.h>
14#include <linux/mm.h>
15#include <linux/mman.h>
16#include <linux/module.h>
17#include <linux/printk.h>
18#include <linux/slab.h>
19#include <linux/string.h>
20#include <linux/uaccess.h>
21#include <linux/io.h>
22
23#include <asm/page.h>
24
25/*
26 * Note: test functions are marked noinline so that their names appear in
27 * reports.
28 */
29
30static 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
46static 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
62static 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
79static 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
98static 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
114static 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
130static 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
148static 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
167static 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
185static 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
205static 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
221static 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
238static 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
254static 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
270static 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
286static 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
302static 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
318static 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
343static noinline void __init kfree_via_page(void)
344{
345 char *ptr;
346 size_t size = 8;
347 struct page *page;
348 unsigned long offset;
349
350 pr_info("invalid-free false positive (via page)\n");
351 ptr = kmalloc(size, GFP_KERNEL);
352 if (!ptr) {
353 pr_err("Allocation failed\n");
354 return;
355 }
356
357 page = virt_to_page(ptr);
358 offset = offset_in_page(ptr);
359 kfree(page_address(page) + offset);
360}
361
362static noinline void __init kfree_via_phys(void)
363{
364 char *ptr;
365 size_t size = 8;
366 phys_addr_t phys;
367
368 pr_info("invalid-free false positive (via phys)\n");
369 ptr = kmalloc(size, GFP_KERNEL);
370 if (!ptr) {
371 pr_err("Allocation failed\n");
372 return;
373 }
374
375 phys = virt_to_phys(ptr);
376 kfree(phys_to_virt(phys));
377}
378
379static noinline void __init kmem_cache_oob(void)
380{
381 char *p;
382 size_t size = 200;
383 struct kmem_cache *cache = kmem_cache_create("test_cache",
384 size, 0,
385 0, NULL);
386 if (!cache) {
387 pr_err("Cache allocation failed\n");
388 return;
389 }
390 pr_info("out-of-bounds in kmem_cache_alloc\n");
391 p = kmem_cache_alloc(cache, GFP_KERNEL);
392 if (!p) {
393 pr_err("Allocation failed\n");
394 kmem_cache_destroy(cache);
395 return;
396 }
397
398 *p = p[size];
399 kmem_cache_free(cache, p);
400 kmem_cache_destroy(cache);
401}
402
403static noinline void __init memcg_accounted_kmem_cache(void)
404{
405 int i;
406 char *p;
407 size_t size = 200;
408 struct kmem_cache *cache;
409
410 cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
411 if (!cache) {
412 pr_err("Cache allocation failed\n");
413 return;
414 }
415
416 pr_info("allocate memcg accounted object\n");
417 /*
418 * Several allocations with a delay to allow for lazy per memcg kmem
419 * cache creation.
420 */
421 for (i = 0; i < 5; i++) {
422 p = kmem_cache_alloc(cache, GFP_KERNEL);
423 if (!p)
424 goto free_cache;
425
426 kmem_cache_free(cache, p);
427 msleep(100);
428 }
429
430free_cache:
431 kmem_cache_destroy(cache);
432}
433
434static char global_array[10];
435
436static noinline void __init kasan_global_oob(void)
437{
438 volatile int i = 3;
439 char *p = &global_array[ARRAY_SIZE(global_array) + i];
440
441 pr_info("out-of-bounds global variable\n");
442 *(volatile char *)p;
443}
444
445static noinline void __init kasan_stack_oob(void)
446{
447 char stack_array[10];
448 volatile int i = 0;
449 char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
450
451 pr_info("out-of-bounds on stack\n");
452 *(volatile char *)p;
453}
454
455static noinline void __init ksize_unpoisons_memory(void)
456{
457 char *ptr;
458 size_t size = 123, real_size;
459
460 pr_info("ksize() unpoisons the whole allocated chunk\n");
461 ptr = kmalloc(size, GFP_KERNEL);
462 if (!ptr) {
463 pr_err("Allocation failed\n");
464 return;
465 }
466 real_size = ksize(ptr);
467 /* This access doesn't trigger an error. */
468 ptr[size] = 'x';
469 /* This one does. */
470 ptr[real_size] = 'y';
471 kfree(ptr);
472}
473
474static noinline void __init copy_user_test(void)
475{
476 char *kmem;
477 char __user *usermem;
478 size_t size = 10;
479 int unused;
480
481 kmem = kmalloc(size, GFP_KERNEL);
482 if (!kmem)
483 return;
484
485 usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
486 PROT_READ | PROT_WRITE | PROT_EXEC,
487 MAP_ANONYMOUS | MAP_PRIVATE, 0);
488 if (IS_ERR(usermem)) {
489 pr_err("Failed to allocate user memory\n");
490 kfree(kmem);
491 return;
492 }
493
494 pr_info("out-of-bounds in copy_from_user()\n");
495 unused = copy_from_user(kmem, usermem, size + 1);
496
497 pr_info("out-of-bounds in copy_to_user()\n");
498 unused = copy_to_user(usermem, kmem, size + 1);
499
500 pr_info("out-of-bounds in __copy_from_user()\n");
501 unused = __copy_from_user(kmem, usermem, size + 1);
502
503 pr_info("out-of-bounds in __copy_to_user()\n");
504 unused = __copy_to_user(usermem, kmem, size + 1);
505
506 pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
507 unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
508
509 pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
510 unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
511
512 pr_info("out-of-bounds in strncpy_from_user()\n");
513 unused = strncpy_from_user(kmem, usermem, size + 1);
514
515 vm_munmap((unsigned long)usermem, PAGE_SIZE);
516 kfree(kmem);
517}
518
519static noinline void __init kasan_alloca_oob_left(void)
520{
521 volatile int i = 10;
522 char alloca_array[i];
523 char *p = alloca_array - 1;
524
525 pr_info("out-of-bounds to left on alloca\n");
526 *(volatile char *)p;
527}
528
529static noinline void __init kasan_alloca_oob_right(void)
530{
531 volatile int i = 10;
532 char alloca_array[i];
533 char *p = alloca_array + i;
534
535 pr_info("out-of-bounds to right on alloca\n");
536 *(volatile char *)p;
537}
538
539static noinline void __init kmem_cache_double_free(void)
540{
541 char *p;
542 size_t size = 200;
543 struct kmem_cache *cache;
544
545 cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
546 if (!cache) {
547 pr_err("Cache allocation failed\n");
548 return;
549 }
550 pr_info("double-free on heap object\n");
551 p = kmem_cache_alloc(cache, GFP_KERNEL);
552 if (!p) {
553 pr_err("Allocation failed\n");
554 kmem_cache_destroy(cache);
555 return;
556 }
557
558 kmem_cache_free(cache, p);
559 kmem_cache_free(cache, p);
560 kmem_cache_destroy(cache);
561}
562
563static noinline void __init kmem_cache_invalid_free(void)
564{
565 char *p;
566 size_t size = 200;
567 struct kmem_cache *cache;
568
569 cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
570 NULL);
571 if (!cache) {
572 pr_err("Cache allocation failed\n");
573 return;
574 }
575 pr_info("invalid-free of heap object\n");
576 p = kmem_cache_alloc(cache, GFP_KERNEL);
577 if (!p) {
578 pr_err("Allocation failed\n");
579 kmem_cache_destroy(cache);
580 return;
581 }
582
583 /* Trigger invalid free, the object doesn't get freed */
584 kmem_cache_free(cache, p + 1);
585
586 /*
587 * Properly free the object to prevent the "Objects remaining in
588 * test_cache on __kmem_cache_shutdown" BUG failure.
589 */
590 kmem_cache_free(cache, p);
591
592 kmem_cache_destroy(cache);
593}
594
595static noinline void __init kasan_memchr(void)
596{
597 char *ptr;
598 size_t size = 24;
599
600 pr_info("out-of-bounds in memchr\n");
601 ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
602 if (!ptr)
603 return;
604
605 memchr(ptr, '1', size + 1);
606 kfree(ptr);
607}
608
609static noinline void __init kasan_memcmp(void)
610{
611 char *ptr;
612 size_t size = 24;
613 int arr[9];
614
615 pr_info("out-of-bounds in memcmp\n");
616 ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
617 if (!ptr)
618 return;
619
620 memset(arr, 0, sizeof(arr));
621 memcmp(ptr, arr, size+1);
622 kfree(ptr);
623}
624
625static noinline void __init kasan_strings(void)
626{
627 char *ptr;
628 size_t size = 24;
629
630 pr_info("use-after-free in strchr\n");
631 ptr = kmalloc(size, GFP_KERNEL | __GFP_ZERO);
632 if (!ptr)
633 return;
634
635 kfree(ptr);
636
637 /*
638 * Try to cause only 1 invalid access (less spam in dmesg).
639 * For that we need ptr to point to zeroed byte.
640 * Skip metadata that could be stored in freed object so ptr
641 * will likely point to zeroed byte.
642 */
643 ptr += 16;
644 strchr(ptr, '1');
645
646 pr_info("use-after-free in strrchr\n");
647 strrchr(ptr, '1');
648
649 pr_info("use-after-free in strcmp\n");
650 strcmp(ptr, "2");
651
652 pr_info("use-after-free in strncmp\n");
653 strncmp(ptr, "2", 1);
654
655 pr_info("use-after-free in strlen\n");
656 strlen(ptr);
657
658 pr_info("use-after-free in strnlen\n");
659 strnlen(ptr, 1);
660}
661
662static noinline void __init kasan_bitops(void)
663{
664 /*
665 * Allocate 1 more byte, which causes kzalloc to round up to 16-bytes;
666 * this way we do not actually corrupt other memory.
667 */
668 long *bits = kzalloc(sizeof(*bits) + 1, GFP_KERNEL);
669 if (!bits)
670 return;
671
672 /*
673 * Below calls try to access bit within allocated memory; however, the
674 * below accesses are still out-of-bounds, since bitops are defined to
675 * operate on the whole long the bit is in.
676 */
677 pr_info("out-of-bounds in set_bit\n");
678 set_bit(BITS_PER_LONG, bits);
679
680 pr_info("out-of-bounds in __set_bit\n");
681 __set_bit(BITS_PER_LONG, bits);
682
683 pr_info("out-of-bounds in clear_bit\n");
684 clear_bit(BITS_PER_LONG, bits);
685
686 pr_info("out-of-bounds in __clear_bit\n");
687 __clear_bit(BITS_PER_LONG, bits);
688
689 pr_info("out-of-bounds in clear_bit_unlock\n");
690 clear_bit_unlock(BITS_PER_LONG, bits);
691
692 pr_info("out-of-bounds in __clear_bit_unlock\n");
693 __clear_bit_unlock(BITS_PER_LONG, bits);
694
695 pr_info("out-of-bounds in change_bit\n");
696 change_bit(BITS_PER_LONG, bits);
697
698 pr_info("out-of-bounds in __change_bit\n");
699 __change_bit(BITS_PER_LONG, bits);
700
701 /*
702 * Below calls try to access bit beyond allocated memory.
703 */
704 pr_info("out-of-bounds in test_and_set_bit\n");
705 test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
706
707 pr_info("out-of-bounds in __test_and_set_bit\n");
708 __test_and_set_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
709
710 pr_info("out-of-bounds in test_and_set_bit_lock\n");
711 test_and_set_bit_lock(BITS_PER_LONG + BITS_PER_BYTE, bits);
712
713 pr_info("out-of-bounds in test_and_clear_bit\n");
714 test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
715
716 pr_info("out-of-bounds in __test_and_clear_bit\n");
717 __test_and_clear_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
718
719 pr_info("out-of-bounds in test_and_change_bit\n");
720 test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
721
722 pr_info("out-of-bounds in __test_and_change_bit\n");
723 __test_and_change_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
724
725 pr_info("out-of-bounds in test_bit\n");
726 (void)test_bit(BITS_PER_LONG + BITS_PER_BYTE, bits);
727
728#if defined(clear_bit_unlock_is_negative_byte)
729 pr_info("out-of-bounds in clear_bit_unlock_is_negative_byte\n");
730 clear_bit_unlock_is_negative_byte(BITS_PER_LONG + BITS_PER_BYTE, bits);
731#endif
732 kfree(bits);
733}
734
735static noinline void __init kmalloc_double_kzfree(void)
736{
737 char *ptr;
738 size_t size = 16;
739
740 pr_info("double-free (kzfree)\n");
741 ptr = kmalloc(size, GFP_KERNEL);
742 if (!ptr) {
743 pr_err("Allocation failed\n");
744 return;
745 }
746
747 kzfree(ptr);
748 kzfree(ptr);
749}
750
751static int __init kmalloc_tests_init(void)
752{
753 /*
754 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
755 * report for the first case.
756 */
757 bool multishot = kasan_save_enable_multi_shot();
758
759 kmalloc_oob_right();
760 kmalloc_oob_left();
761 kmalloc_node_oob_right();
762#ifdef CONFIG_SLUB
763 kmalloc_pagealloc_oob_right();
764 kmalloc_pagealloc_uaf();
765 kmalloc_pagealloc_invalid_free();
766#endif
767 kmalloc_large_oob_right();
768 kmalloc_oob_krealloc_more();
769 kmalloc_oob_krealloc_less();
770 kmalloc_oob_16();
771 kmalloc_oob_in_memset();
772 kmalloc_oob_memset_2();
773 kmalloc_oob_memset_4();
774 kmalloc_oob_memset_8();
775 kmalloc_oob_memset_16();
776 kmalloc_uaf();
777 kmalloc_uaf_memset();
778 kmalloc_uaf2();
779 kfree_via_page();
780 kfree_via_phys();
781 kmem_cache_oob();
782 memcg_accounted_kmem_cache();
783 kasan_stack_oob();
784 kasan_global_oob();
785 kasan_alloca_oob_left();
786 kasan_alloca_oob_right();
787 ksize_unpoisons_memory();
788 copy_user_test();
789 kmem_cache_double_free();
790 kmem_cache_invalid_free();
791 kasan_memchr();
792 kasan_memcmp();
793 kasan_strings();
794 kasan_bitops();
795 kmalloc_double_kzfree();
796
797 kasan_restore_multi_shot(multishot);
798
799 return -EAGAIN;
800}
801
802module_init(kmalloc_tests_init);
803MODULE_LICENSE("GPL");