Commit | Line | Data |
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0b24becc AR |
1 | /* |
2 | * This file contains shadow memory manipulation code. | |
3 | * | |
4 | * Copyright (c) 2014 Samsung Electronics Co., Ltd. | |
2baf9e89 | 5 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> |
0b24becc | 6 | * |
5d0926ef | 7 | * Some code borrowed from https://github.com/xairy/kasan-prototype by |
0b24becc AR |
8 | * Andrey Konovalov <adech.fo@gmail.com> |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License version 2 as | |
12 | * published by the Free Software Foundation. | |
13 | * | |
14 | */ | |
15 | ||
16 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
17 | #define DISABLE_BRANCH_PROFILING | |
18 | ||
19 | #include <linux/export.h> | |
20 | #include <linux/init.h> | |
21 | #include <linux/kernel.h> | |
45937254 | 22 | #include <linux/kmemleak.h> |
0b24becc | 23 | #include <linux/memblock.h> |
786a8959 | 24 | #include <linux/memory.h> |
0b24becc | 25 | #include <linux/mm.h> |
bebf56a1 | 26 | #include <linux/module.h> |
0b24becc AR |
27 | #include <linux/printk.h> |
28 | #include <linux/sched.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/stacktrace.h> | |
31 | #include <linux/string.h> | |
32 | #include <linux/types.h> | |
a5af5aa8 | 33 | #include <linux/vmalloc.h> |
0b24becc AR |
34 | #include <linux/kasan.h> |
35 | ||
36 | #include "kasan.h" | |
0316bec2 | 37 | #include "../slab.h" |
0b24becc AR |
38 | |
39 | /* | |
40 | * Poisons the shadow memory for 'size' bytes starting from 'addr'. | |
41 | * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE. | |
42 | */ | |
43 | static void kasan_poison_shadow(const void *address, size_t size, u8 value) | |
44 | { | |
45 | void *shadow_start, *shadow_end; | |
46 | ||
47 | shadow_start = kasan_mem_to_shadow(address); | |
48 | shadow_end = kasan_mem_to_shadow(address + size); | |
49 | ||
50 | memset(shadow_start, value, shadow_end - shadow_start); | |
51 | } | |
52 | ||
53 | void kasan_unpoison_shadow(const void *address, size_t size) | |
54 | { | |
55 | kasan_poison_shadow(address, size, 0); | |
56 | ||
57 | if (size & KASAN_SHADOW_MASK) { | |
58 | u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size); | |
59 | *shadow = size & KASAN_SHADOW_MASK; | |
60 | } | |
61 | } | |
62 | ||
63 | ||
64 | /* | |
65 | * All functions below always inlined so compiler could | |
66 | * perform better optimizations in each of __asan_loadX/__assn_storeX | |
67 | * depending on memory access size X. | |
68 | */ | |
69 | ||
70 | static __always_inline bool memory_is_poisoned_1(unsigned long addr) | |
71 | { | |
72 | s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr); | |
73 | ||
74 | if (unlikely(shadow_value)) { | |
75 | s8 last_accessible_byte = addr & KASAN_SHADOW_MASK; | |
76 | return unlikely(last_accessible_byte >= shadow_value); | |
77 | } | |
78 | ||
79 | return false; | |
80 | } | |
81 | ||
82 | static __always_inline bool memory_is_poisoned_2(unsigned long addr) | |
83 | { | |
84 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); | |
85 | ||
86 | if (unlikely(*shadow_addr)) { | |
87 | if (memory_is_poisoned_1(addr + 1)) | |
88 | return true; | |
89 | ||
10f70262 XQ |
90 | /* |
91 | * If single shadow byte covers 2-byte access, we don't | |
92 | * need to do anything more. Otherwise, test the first | |
93 | * shadow byte. | |
94 | */ | |
0b24becc AR |
95 | if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0)) |
96 | return false; | |
97 | ||
98 | return unlikely(*(u8 *)shadow_addr); | |
99 | } | |
100 | ||
101 | return false; | |
102 | } | |
103 | ||
104 | static __always_inline bool memory_is_poisoned_4(unsigned long addr) | |
105 | { | |
106 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); | |
107 | ||
108 | if (unlikely(*shadow_addr)) { | |
109 | if (memory_is_poisoned_1(addr + 3)) | |
110 | return true; | |
111 | ||
10f70262 XQ |
112 | /* |
113 | * If single shadow byte covers 4-byte access, we don't | |
114 | * need to do anything more. Otherwise, test the first | |
115 | * shadow byte. | |
116 | */ | |
0b24becc AR |
117 | if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3)) |
118 | return false; | |
119 | ||
120 | return unlikely(*(u8 *)shadow_addr); | |
121 | } | |
122 | ||
123 | return false; | |
124 | } | |
125 | ||
126 | static __always_inline bool memory_is_poisoned_8(unsigned long addr) | |
127 | { | |
128 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); | |
129 | ||
130 | if (unlikely(*shadow_addr)) { | |
131 | if (memory_is_poisoned_1(addr + 7)) | |
132 | return true; | |
133 | ||
10f70262 XQ |
134 | /* |
135 | * If single shadow byte covers 8-byte access, we don't | |
136 | * need to do anything more. Otherwise, test the first | |
137 | * shadow byte. | |
138 | */ | |
139 | if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) | |
0b24becc AR |
140 | return false; |
141 | ||
142 | return unlikely(*(u8 *)shadow_addr); | |
143 | } | |
144 | ||
145 | return false; | |
146 | } | |
147 | ||
148 | static __always_inline bool memory_is_poisoned_16(unsigned long addr) | |
149 | { | |
150 | u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr); | |
151 | ||
152 | if (unlikely(*shadow_addr)) { | |
153 | u16 shadow_first_bytes = *(u16 *)shadow_addr; | |
0b24becc AR |
154 | |
155 | if (unlikely(shadow_first_bytes)) | |
156 | return true; | |
157 | ||
10f70262 XQ |
158 | /* |
159 | * If two shadow bytes covers 16-byte access, we don't | |
160 | * need to do anything more. Otherwise, test the last | |
161 | * shadow byte. | |
162 | */ | |
163 | if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) | |
0b24becc AR |
164 | return false; |
165 | ||
166 | return memory_is_poisoned_1(addr + 15); | |
167 | } | |
168 | ||
169 | return false; | |
170 | } | |
171 | ||
172 | static __always_inline unsigned long bytes_is_zero(const u8 *start, | |
173 | size_t size) | |
174 | { | |
175 | while (size) { | |
176 | if (unlikely(*start)) | |
177 | return (unsigned long)start; | |
178 | start++; | |
179 | size--; | |
180 | } | |
181 | ||
182 | return 0; | |
183 | } | |
184 | ||
185 | static __always_inline unsigned long memory_is_zero(const void *start, | |
186 | const void *end) | |
187 | { | |
188 | unsigned int words; | |
189 | unsigned long ret; | |
190 | unsigned int prefix = (unsigned long)start % 8; | |
191 | ||
192 | if (end - start <= 16) | |
193 | return bytes_is_zero(start, end - start); | |
194 | ||
195 | if (prefix) { | |
196 | prefix = 8 - prefix; | |
197 | ret = bytes_is_zero(start, prefix); | |
198 | if (unlikely(ret)) | |
199 | return ret; | |
200 | start += prefix; | |
201 | } | |
202 | ||
203 | words = (end - start) / 8; | |
204 | while (words) { | |
205 | if (unlikely(*(u64 *)start)) | |
206 | return bytes_is_zero(start, 8); | |
207 | start += 8; | |
208 | words--; | |
209 | } | |
210 | ||
211 | return bytes_is_zero(start, (end - start) % 8); | |
212 | } | |
213 | ||
214 | static __always_inline bool memory_is_poisoned_n(unsigned long addr, | |
215 | size_t size) | |
216 | { | |
217 | unsigned long ret; | |
218 | ||
219 | ret = memory_is_zero(kasan_mem_to_shadow((void *)addr), | |
220 | kasan_mem_to_shadow((void *)addr + size - 1) + 1); | |
221 | ||
222 | if (unlikely(ret)) { | |
223 | unsigned long last_byte = addr + size - 1; | |
224 | s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte); | |
225 | ||
226 | if (unlikely(ret != (unsigned long)last_shadow || | |
e0d57714 | 227 | ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow))) |
0b24becc AR |
228 | return true; |
229 | } | |
230 | return false; | |
231 | } | |
232 | ||
233 | static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size) | |
234 | { | |
235 | if (__builtin_constant_p(size)) { | |
236 | switch (size) { | |
237 | case 1: | |
238 | return memory_is_poisoned_1(addr); | |
239 | case 2: | |
240 | return memory_is_poisoned_2(addr); | |
241 | case 4: | |
242 | return memory_is_poisoned_4(addr); | |
243 | case 8: | |
244 | return memory_is_poisoned_8(addr); | |
245 | case 16: | |
246 | return memory_is_poisoned_16(addr); | |
247 | default: | |
248 | BUILD_BUG(); | |
249 | } | |
250 | } | |
251 | ||
252 | return memory_is_poisoned_n(addr, size); | |
253 | } | |
254 | ||
255 | ||
256 | static __always_inline void check_memory_region(unsigned long addr, | |
257 | size_t size, bool write) | |
258 | { | |
0b24becc AR |
259 | if (unlikely(size == 0)) |
260 | return; | |
261 | ||
262 | if (unlikely((void *)addr < | |
263 | kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) { | |
e9121076 | 264 | kasan_report(addr, size, write, _RET_IP_); |
0b24becc AR |
265 | return; |
266 | } | |
267 | ||
268 | if (likely(!memory_is_poisoned(addr, size))) | |
269 | return; | |
270 | ||
271 | kasan_report(addr, size, write, _RET_IP_); | |
272 | } | |
273 | ||
393f203f AR |
274 | void __asan_loadN(unsigned long addr, size_t size); |
275 | void __asan_storeN(unsigned long addr, size_t size); | |
276 | ||
277 | #undef memset | |
278 | void *memset(void *addr, int c, size_t len) | |
279 | { | |
280 | __asan_storeN((unsigned long)addr, len); | |
281 | ||
282 | return __memset(addr, c, len); | |
283 | } | |
284 | ||
285 | #undef memmove | |
286 | void *memmove(void *dest, const void *src, size_t len) | |
287 | { | |
288 | __asan_loadN((unsigned long)src, len); | |
289 | __asan_storeN((unsigned long)dest, len); | |
290 | ||
291 | return __memmove(dest, src, len); | |
292 | } | |
293 | ||
294 | #undef memcpy | |
295 | void *memcpy(void *dest, const void *src, size_t len) | |
296 | { | |
297 | __asan_loadN((unsigned long)src, len); | |
298 | __asan_storeN((unsigned long)dest, len); | |
299 | ||
300 | return __memcpy(dest, src, len); | |
301 | } | |
302 | ||
b8c73fc2 AR |
303 | void kasan_alloc_pages(struct page *page, unsigned int order) |
304 | { | |
305 | if (likely(!PageHighMem(page))) | |
306 | kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order); | |
307 | } | |
308 | ||
309 | void kasan_free_pages(struct page *page, unsigned int order) | |
310 | { | |
311 | if (likely(!PageHighMem(page))) | |
312 | kasan_poison_shadow(page_address(page), | |
313 | PAGE_SIZE << order, | |
314 | KASAN_FREE_PAGE); | |
315 | } | |
316 | ||
0316bec2 AR |
317 | void kasan_poison_slab(struct page *page) |
318 | { | |
319 | kasan_poison_shadow(page_address(page), | |
320 | PAGE_SIZE << compound_order(page), | |
321 | KASAN_KMALLOC_REDZONE); | |
322 | } | |
323 | ||
324 | void kasan_unpoison_object_data(struct kmem_cache *cache, void *object) | |
325 | { | |
326 | kasan_unpoison_shadow(object, cache->object_size); | |
327 | } | |
328 | ||
329 | void kasan_poison_object_data(struct kmem_cache *cache, void *object) | |
330 | { | |
331 | kasan_poison_shadow(object, | |
332 | round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE), | |
333 | KASAN_KMALLOC_REDZONE); | |
334 | } | |
335 | ||
336 | void kasan_slab_alloc(struct kmem_cache *cache, void *object) | |
337 | { | |
338 | kasan_kmalloc(cache, object, cache->object_size); | |
339 | } | |
340 | ||
341 | void kasan_slab_free(struct kmem_cache *cache, void *object) | |
342 | { | |
343 | unsigned long size = cache->object_size; | |
344 | unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE); | |
345 | ||
346 | /* RCU slabs could be legally used after free within the RCU period */ | |
347 | if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU)) | |
348 | return; | |
349 | ||
350 | kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); | |
351 | } | |
352 | ||
353 | void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size) | |
354 | { | |
355 | unsigned long redzone_start; | |
356 | unsigned long redzone_end; | |
357 | ||
358 | if (unlikely(object == NULL)) | |
359 | return; | |
360 | ||
361 | redzone_start = round_up((unsigned long)(object + size), | |
362 | KASAN_SHADOW_SCALE_SIZE); | |
363 | redzone_end = round_up((unsigned long)object + cache->object_size, | |
364 | KASAN_SHADOW_SCALE_SIZE); | |
365 | ||
366 | kasan_unpoison_shadow(object, size); | |
367 | kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, | |
368 | KASAN_KMALLOC_REDZONE); | |
369 | } | |
370 | EXPORT_SYMBOL(kasan_kmalloc); | |
371 | ||
372 | void kasan_kmalloc_large(const void *ptr, size_t size) | |
373 | { | |
374 | struct page *page; | |
375 | unsigned long redzone_start; | |
376 | unsigned long redzone_end; | |
377 | ||
378 | if (unlikely(ptr == NULL)) | |
379 | return; | |
380 | ||
381 | page = virt_to_page(ptr); | |
382 | redzone_start = round_up((unsigned long)(ptr + size), | |
383 | KASAN_SHADOW_SCALE_SIZE); | |
384 | redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page)); | |
385 | ||
386 | kasan_unpoison_shadow(ptr, size); | |
387 | kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, | |
388 | KASAN_PAGE_REDZONE); | |
389 | } | |
390 | ||
391 | void kasan_krealloc(const void *object, size_t size) | |
392 | { | |
393 | struct page *page; | |
394 | ||
395 | if (unlikely(object == ZERO_SIZE_PTR)) | |
396 | return; | |
397 | ||
398 | page = virt_to_head_page(object); | |
399 | ||
400 | if (unlikely(!PageSlab(page))) | |
401 | kasan_kmalloc_large(object, size); | |
402 | else | |
403 | kasan_kmalloc(page->slab_cache, object, size); | |
404 | } | |
405 | ||
92393615 AR |
406 | void kasan_kfree(void *ptr) |
407 | { | |
408 | struct page *page; | |
409 | ||
410 | page = virt_to_head_page(ptr); | |
411 | ||
412 | if (unlikely(!PageSlab(page))) | |
413 | kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), | |
414 | KASAN_FREE_PAGE); | |
415 | else | |
416 | kasan_slab_free(page->slab_cache, ptr); | |
417 | } | |
418 | ||
0316bec2 AR |
419 | void kasan_kfree_large(const void *ptr) |
420 | { | |
421 | struct page *page = virt_to_page(ptr); | |
422 | ||
423 | kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), | |
424 | KASAN_FREE_PAGE); | |
425 | } | |
426 | ||
bebf56a1 AR |
427 | int kasan_module_alloc(void *addr, size_t size) |
428 | { | |
429 | void *ret; | |
430 | size_t shadow_size; | |
431 | unsigned long shadow_start; | |
432 | ||
433 | shadow_start = (unsigned long)kasan_mem_to_shadow(addr); | |
434 | shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT, | |
435 | PAGE_SIZE); | |
436 | ||
437 | if (WARN_ON(!PAGE_ALIGNED(shadow_start))) | |
438 | return -EINVAL; | |
439 | ||
440 | ret = __vmalloc_node_range(shadow_size, 1, shadow_start, | |
441 | shadow_start + shadow_size, | |
442 | GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, | |
443 | PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE, | |
444 | __builtin_return_address(0)); | |
a5af5aa8 AR |
445 | |
446 | if (ret) { | |
447 | find_vm_area(addr)->flags |= VM_KASAN; | |
45937254 | 448 | kmemleak_ignore(ret); |
a5af5aa8 AR |
449 | return 0; |
450 | } | |
451 | ||
452 | return -ENOMEM; | |
bebf56a1 AR |
453 | } |
454 | ||
a5af5aa8 | 455 | void kasan_free_shadow(const struct vm_struct *vm) |
bebf56a1 | 456 | { |
a5af5aa8 AR |
457 | if (vm->flags & VM_KASAN) |
458 | vfree(kasan_mem_to_shadow(vm->addr)); | |
bebf56a1 AR |
459 | } |
460 | ||
461 | static void register_global(struct kasan_global *global) | |
462 | { | |
463 | size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE); | |
464 | ||
465 | kasan_unpoison_shadow(global->beg, global->size); | |
466 | ||
467 | kasan_poison_shadow(global->beg + aligned_size, | |
468 | global->size_with_redzone - aligned_size, | |
469 | KASAN_GLOBAL_REDZONE); | |
470 | } | |
471 | ||
472 | void __asan_register_globals(struct kasan_global *globals, size_t size) | |
473 | { | |
474 | int i; | |
475 | ||
476 | for (i = 0; i < size; i++) | |
477 | register_global(&globals[i]); | |
478 | } | |
479 | EXPORT_SYMBOL(__asan_register_globals); | |
480 | ||
481 | void __asan_unregister_globals(struct kasan_global *globals, size_t size) | |
482 | { | |
483 | } | |
484 | EXPORT_SYMBOL(__asan_unregister_globals); | |
485 | ||
0b24becc AR |
486 | #define DEFINE_ASAN_LOAD_STORE(size) \ |
487 | void __asan_load##size(unsigned long addr) \ | |
488 | { \ | |
489 | check_memory_region(addr, size, false); \ | |
490 | } \ | |
491 | EXPORT_SYMBOL(__asan_load##size); \ | |
492 | __alias(__asan_load##size) \ | |
493 | void __asan_load##size##_noabort(unsigned long); \ | |
494 | EXPORT_SYMBOL(__asan_load##size##_noabort); \ | |
495 | void __asan_store##size(unsigned long addr) \ | |
496 | { \ | |
497 | check_memory_region(addr, size, true); \ | |
498 | } \ | |
499 | EXPORT_SYMBOL(__asan_store##size); \ | |
500 | __alias(__asan_store##size) \ | |
501 | void __asan_store##size##_noabort(unsigned long); \ | |
502 | EXPORT_SYMBOL(__asan_store##size##_noabort) | |
503 | ||
504 | DEFINE_ASAN_LOAD_STORE(1); | |
505 | DEFINE_ASAN_LOAD_STORE(2); | |
506 | DEFINE_ASAN_LOAD_STORE(4); | |
507 | DEFINE_ASAN_LOAD_STORE(8); | |
508 | DEFINE_ASAN_LOAD_STORE(16); | |
509 | ||
510 | void __asan_loadN(unsigned long addr, size_t size) | |
511 | { | |
512 | check_memory_region(addr, size, false); | |
513 | } | |
514 | EXPORT_SYMBOL(__asan_loadN); | |
515 | ||
516 | __alias(__asan_loadN) | |
517 | void __asan_loadN_noabort(unsigned long, size_t); | |
518 | EXPORT_SYMBOL(__asan_loadN_noabort); | |
519 | ||
520 | void __asan_storeN(unsigned long addr, size_t size) | |
521 | { | |
522 | check_memory_region(addr, size, true); | |
523 | } | |
524 | EXPORT_SYMBOL(__asan_storeN); | |
525 | ||
526 | __alias(__asan_storeN) | |
527 | void __asan_storeN_noabort(unsigned long, size_t); | |
528 | EXPORT_SYMBOL(__asan_storeN_noabort); | |
529 | ||
530 | /* to shut up compiler complaints */ | |
531 | void __asan_handle_no_return(void) {} | |
532 | EXPORT_SYMBOL(__asan_handle_no_return); | |
786a8959 AR |
533 | |
534 | #ifdef CONFIG_MEMORY_HOTPLUG | |
535 | static int kasan_mem_notifier(struct notifier_block *nb, | |
536 | unsigned long action, void *data) | |
537 | { | |
538 | return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK; | |
539 | } | |
540 | ||
541 | static int __init kasan_memhotplug_init(void) | |
542 | { | |
25add7ec | 543 | pr_err("WARNING: KASAN doesn't support memory hot-add\n"); |
786a8959 AR |
544 | pr_err("Memory hot-add will be disabled\n"); |
545 | ||
546 | hotplug_memory_notifier(kasan_mem_notifier, 0); | |
547 | ||
548 | return 0; | |
549 | } | |
550 | ||
551 | module_init(kasan_memhotplug_init); | |
552 | #endif |