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 kfree(ptr2);
161 return;
162 }
163
164 ptr2[size2] = 'x';
165 kfree(ptr2);
166 }
167
kmalloc_oob_krealloc_less(void)168 static noinline void __init kmalloc_oob_krealloc_less(void)
169 {
170 char *ptr1, *ptr2;
171 size_t size1 = 17;
172 size_t size2 = 15;
173
174 pr_info("out-of-bounds after krealloc less\n");
175 ptr1 = kmalloc(size1, GFP_KERNEL);
176 ptr2 = krealloc(ptr1, size2, GFP_KERNEL);
177 if (!ptr1 || !ptr2) {
178 pr_err("Allocation failed\n");
179 kfree(ptr1);
180 return;
181 }
182 ptr2[size2] = 'x';
183 kfree(ptr2);
184 }
185
kmalloc_oob_16(void)186 static noinline void __init kmalloc_oob_16(void)
187 {
188 struct {
189 u64 words[2];
190 } *ptr1, *ptr2;
191
192 pr_info("kmalloc out-of-bounds for 16-bytes access\n");
193 ptr1 = kmalloc(sizeof(*ptr1) - 3, GFP_KERNEL);
194 ptr2 = kmalloc(sizeof(*ptr2), GFP_KERNEL);
195 if (!ptr1 || !ptr2) {
196 pr_err("Allocation failed\n");
197 kfree(ptr1);
198 kfree(ptr2);
199 return;
200 }
201 *ptr1 = *ptr2;
202 kfree(ptr1);
203 kfree(ptr2);
204 }
205
kmalloc_oob_memset_2(void)206 static noinline void __init kmalloc_oob_memset_2(void)
207 {
208 char *ptr;
209 size_t size = 8;
210
211 pr_info("out-of-bounds in memset2\n");
212 ptr = kmalloc(size, GFP_KERNEL);
213 if (!ptr) {
214 pr_err("Allocation failed\n");
215 return;
216 }
217
218 memset(ptr+7, 0, 2);
219 kfree(ptr);
220 }
221
kmalloc_oob_memset_4(void)222 static noinline void __init kmalloc_oob_memset_4(void)
223 {
224 char *ptr;
225 size_t size = 8;
226
227 pr_info("out-of-bounds in memset4\n");
228 ptr = kmalloc(size, GFP_KERNEL);
229 if (!ptr) {
230 pr_err("Allocation failed\n");
231 return;
232 }
233
234 memset(ptr+5, 0, 4);
235 kfree(ptr);
236 }
237
238
kmalloc_oob_memset_8(void)239 static noinline void __init kmalloc_oob_memset_8(void)
240 {
241 char *ptr;
242 size_t size = 8;
243
244 pr_info("out-of-bounds in memset8\n");
245 ptr = kmalloc(size, GFP_KERNEL);
246 if (!ptr) {
247 pr_err("Allocation failed\n");
248 return;
249 }
250
251 memset(ptr+1, 0, 8);
252 kfree(ptr);
253 }
254
kmalloc_oob_memset_16(void)255 static noinline void __init kmalloc_oob_memset_16(void)
256 {
257 char *ptr;
258 size_t size = 16;
259
260 pr_info("out-of-bounds in memset16\n");
261 ptr = kmalloc(size, GFP_KERNEL);
262 if (!ptr) {
263 pr_err("Allocation failed\n");
264 return;
265 }
266
267 memset(ptr+1, 0, 16);
268 kfree(ptr);
269 }
270
kmalloc_oob_in_memset(void)271 static noinline void __init kmalloc_oob_in_memset(void)
272 {
273 char *ptr;
274 size_t size = 666;
275
276 pr_info("out-of-bounds in memset\n");
277 ptr = kmalloc(size, GFP_KERNEL);
278 if (!ptr) {
279 pr_err("Allocation failed\n");
280 return;
281 }
282
283 memset(ptr, 0, size+5);
284 kfree(ptr);
285 }
286
kmalloc_uaf(void)287 static noinline void __init kmalloc_uaf(void)
288 {
289 char *ptr;
290 size_t size = 10;
291
292 pr_info("use-after-free\n");
293 ptr = kmalloc(size, GFP_KERNEL);
294 if (!ptr) {
295 pr_err("Allocation failed\n");
296 return;
297 }
298
299 kfree(ptr);
300 *(ptr + 8) = 'x';
301 }
302
kmalloc_uaf_memset(void)303 static noinline void __init kmalloc_uaf_memset(void)
304 {
305 char *ptr;
306 size_t size = 33;
307
308 pr_info("use-after-free in memset\n");
309 ptr = kmalloc(size, GFP_KERNEL);
310 if (!ptr) {
311 pr_err("Allocation failed\n");
312 return;
313 }
314
315 kfree(ptr);
316 memset(ptr, 0, size);
317 }
318
kmalloc_uaf2(void)319 static noinline void __init kmalloc_uaf2(void)
320 {
321 char *ptr1, *ptr2;
322 size_t size = 43;
323
324 pr_info("use-after-free after another kmalloc\n");
325 ptr1 = kmalloc(size, GFP_KERNEL);
326 if (!ptr1) {
327 pr_err("Allocation failed\n");
328 return;
329 }
330
331 kfree(ptr1);
332 ptr2 = kmalloc(size, GFP_KERNEL);
333 if (!ptr2) {
334 pr_err("Allocation failed\n");
335 return;
336 }
337
338 ptr1[40] = 'x';
339 if (ptr1 == ptr2)
340 pr_err("Could not detect use-after-free: ptr1 == ptr2\n");
341 kfree(ptr2);
342 }
343
kmem_cache_oob(void)344 static noinline void __init kmem_cache_oob(void)
345 {
346 char *p;
347 size_t size = 200;
348 struct kmem_cache *cache = kmem_cache_create("test_cache",
349 size, 0,
350 0, NULL);
351 if (!cache) {
352 pr_err("Cache allocation failed\n");
353 return;
354 }
355 pr_info("out-of-bounds in kmem_cache_alloc\n");
356 p = kmem_cache_alloc(cache, GFP_KERNEL);
357 if (!p) {
358 pr_err("Allocation failed\n");
359 kmem_cache_destroy(cache);
360 return;
361 }
362
363 *p = p[size];
364 kmem_cache_free(cache, p);
365 kmem_cache_destroy(cache);
366 }
367
memcg_accounted_kmem_cache(void)368 static noinline void __init memcg_accounted_kmem_cache(void)
369 {
370 int i;
371 char *p;
372 size_t size = 200;
373 struct kmem_cache *cache;
374
375 cache = kmem_cache_create("test_cache", size, 0, SLAB_ACCOUNT, NULL);
376 if (!cache) {
377 pr_err("Cache allocation failed\n");
378 return;
379 }
380
381 pr_info("allocate memcg accounted object\n");
382 /*
383 * Several allocations with a delay to allow for lazy per memcg kmem
384 * cache creation.
385 */
386 for (i = 0; i < 5; i++) {
387 p = kmem_cache_alloc(cache, GFP_KERNEL);
388 if (!p)
389 goto free_cache;
390
391 kmem_cache_free(cache, p);
392 msleep(100);
393 }
394
395 free_cache:
396 kmem_cache_destroy(cache);
397 }
398
399 static char global_array[10];
400
kasan_global_oob(void)401 static noinline void __init kasan_global_oob(void)
402 {
403 volatile int i = 3;
404 char *p = &global_array[ARRAY_SIZE(global_array) + i];
405
406 pr_info("out-of-bounds global variable\n");
407 *(volatile char *)p;
408 }
409
kasan_stack_oob(void)410 static noinline void __init kasan_stack_oob(void)
411 {
412 char stack_array[10];
413 volatile int i = 0;
414 char *p = &stack_array[ARRAY_SIZE(stack_array) + i];
415
416 pr_info("out-of-bounds on stack\n");
417 *(volatile char *)p;
418 }
419
ksize_unpoisons_memory(void)420 static noinline void __init ksize_unpoisons_memory(void)
421 {
422 char *ptr;
423 size_t size = 123, real_size;
424
425 pr_info("ksize() unpoisons the whole allocated chunk\n");
426 ptr = kmalloc(size, GFP_KERNEL);
427 if (!ptr) {
428 pr_err("Allocation failed\n");
429 return;
430 }
431 real_size = ksize(ptr);
432 /* This access doesn't trigger an error. */
433 ptr[size] = 'x';
434 /* This one does. */
435 ptr[real_size] = 'y';
436 kfree(ptr);
437 }
438
copy_user_test(void)439 static noinline void __init copy_user_test(void)
440 {
441 char *kmem;
442 char __user *usermem;
443 size_t size = 10;
444 int unused;
445
446 kmem = kmalloc(size, GFP_KERNEL);
447 if (!kmem)
448 return;
449
450 usermem = (char __user *)vm_mmap(NULL, 0, PAGE_SIZE,
451 PROT_READ | PROT_WRITE | PROT_EXEC,
452 MAP_ANONYMOUS | MAP_PRIVATE, 0);
453 if (IS_ERR(usermem)) {
454 pr_err("Failed to allocate user memory\n");
455 kfree(kmem);
456 return;
457 }
458
459 pr_info("out-of-bounds in copy_from_user()\n");
460 unused = copy_from_user(kmem, usermem, size + 1);
461
462 pr_info("out-of-bounds in copy_to_user()\n");
463 unused = copy_to_user(usermem, kmem, size + 1);
464
465 pr_info("out-of-bounds in __copy_from_user()\n");
466 unused = __copy_from_user(kmem, usermem, size + 1);
467
468 pr_info("out-of-bounds in __copy_to_user()\n");
469 unused = __copy_to_user(usermem, kmem, size + 1);
470
471 pr_info("out-of-bounds in __copy_from_user_inatomic()\n");
472 unused = __copy_from_user_inatomic(kmem, usermem, size + 1);
473
474 pr_info("out-of-bounds in __copy_to_user_inatomic()\n");
475 unused = __copy_to_user_inatomic(usermem, kmem, size + 1);
476
477 pr_info("out-of-bounds in strncpy_from_user()\n");
478 unused = strncpy_from_user(kmem, usermem, size + 1);
479
480 vm_munmap((unsigned long)usermem, PAGE_SIZE);
481 kfree(kmem);
482 }
483
use_after_scope_test(void)484 static noinline void __init use_after_scope_test(void)
485 {
486 volatile char *volatile p;
487
488 pr_info("use-after-scope on int\n");
489 {
490 int local = 0;
491
492 p = (char *)&local;
493 }
494 p[0] = 1;
495 p[3] = 1;
496
497 pr_info("use-after-scope on array\n");
498 {
499 char local[1024] = {0};
500
501 p = local;
502 }
503 p[0] = 1;
504 p[1023] = 1;
505 }
506
kasan_alloca_oob_left(void)507 static noinline void __init kasan_alloca_oob_left(void)
508 {
509 volatile int i = 10;
510 char alloca_array[i];
511 char *p = alloca_array - 1;
512
513 pr_info("out-of-bounds to left on alloca\n");
514 *(volatile char *)p;
515 }
516
kasan_alloca_oob_right(void)517 static noinline void __init kasan_alloca_oob_right(void)
518 {
519 volatile int i = 10;
520 char alloca_array[i];
521 char *p = alloca_array + i;
522
523 pr_info("out-of-bounds to right on alloca\n");
524 *(volatile char *)p;
525 }
526
kmem_cache_double_free(void)527 static noinline void __init kmem_cache_double_free(void)
528 {
529 char *p;
530 size_t size = 200;
531 struct kmem_cache *cache;
532
533 cache = kmem_cache_create("test_cache", size, 0, 0, NULL);
534 if (!cache) {
535 pr_err("Cache allocation failed\n");
536 return;
537 }
538 pr_info("double-free on heap object\n");
539 p = kmem_cache_alloc(cache, GFP_KERNEL);
540 if (!p) {
541 pr_err("Allocation failed\n");
542 kmem_cache_destroy(cache);
543 return;
544 }
545
546 kmem_cache_free(cache, p);
547 kmem_cache_free(cache, p);
548 kmem_cache_destroy(cache);
549 }
550
kmem_cache_invalid_free(void)551 static noinline void __init kmem_cache_invalid_free(void)
552 {
553 char *p;
554 size_t size = 200;
555 struct kmem_cache *cache;
556
557 cache = kmem_cache_create("test_cache", size, 0, SLAB_TYPESAFE_BY_RCU,
558 NULL);
559 if (!cache) {
560 pr_err("Cache allocation failed\n");
561 return;
562 }
563 pr_info("invalid-free of heap object\n");
564 p = kmem_cache_alloc(cache, GFP_KERNEL);
565 if (!p) {
566 pr_err("Allocation failed\n");
567 kmem_cache_destroy(cache);
568 return;
569 }
570
571 /* Trigger invalid free, the object doesn't get freed */
572 kmem_cache_free(cache, p + 1);
573
574 /*
575 * Properly free the object to prevent the "Objects remaining in
576 * test_cache on __kmem_cache_shutdown" BUG failure.
577 */
578 kmem_cache_free(cache, p);
579
580 kmem_cache_destroy(cache);
581 }
582
kmalloc_tests_init(void)583 static int __init kmalloc_tests_init(void)
584 {
585 /*
586 * Temporarily enable multi-shot mode. Otherwise, we'd only get a
587 * report for the first case.
588 */
589 bool multishot = kasan_save_enable_multi_shot();
590
591 kmalloc_oob_right();
592 kmalloc_oob_left();
593 kmalloc_node_oob_right();
594 #ifdef CONFIG_SLUB
595 kmalloc_pagealloc_oob_right();
596 kmalloc_pagealloc_uaf();
597 kmalloc_pagealloc_invalid_free();
598 #endif
599 kmalloc_large_oob_right();
600 kmalloc_oob_krealloc_more();
601 kmalloc_oob_krealloc_less();
602 kmalloc_oob_16();
603 kmalloc_oob_in_memset();
604 kmalloc_oob_memset_2();
605 kmalloc_oob_memset_4();
606 kmalloc_oob_memset_8();
607 kmalloc_oob_memset_16();
608 kmalloc_uaf();
609 kmalloc_uaf_memset();
610 kmalloc_uaf2();
611 kmem_cache_oob();
612 memcg_accounted_kmem_cache();
613 kasan_stack_oob();
614 kasan_global_oob();
615 kasan_alloca_oob_left();
616 kasan_alloca_oob_right();
617 ksize_unpoisons_memory();
618 copy_user_test();
619 use_after_scope_test();
620 kmem_cache_double_free();
621 kmem_cache_invalid_free();
622
623 kasan_restore_multi_shot(multishot);
624
625 return -EAGAIN;
626 }
627
628 module_init(kmalloc_tests_init);
629 MODULE_LICENSE("GPL");
630