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> |
e3ae1163 | 23 | #include <linux/linkage.h> |
0b24becc | 24 | #include <linux/memblock.h> |
786a8959 | 25 | #include <linux/memory.h> |
0b24becc | 26 | #include <linux/mm.h> |
bebf56a1 | 27 | #include <linux/module.h> |
0b24becc AR |
28 | #include <linux/printk.h> |
29 | #include <linux/sched.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/stacktrace.h> | |
32 | #include <linux/string.h> | |
33 | #include <linux/types.h> | |
a5af5aa8 | 34 | #include <linux/vmalloc.h> |
0b24becc AR |
35 | #include <linux/kasan.h> |
36 | ||
37 | #include "kasan.h" | |
0316bec2 | 38 | #include "../slab.h" |
0b24becc AR |
39 | |
40 | /* | |
41 | * Poisons the shadow memory for 'size' bytes starting from 'addr'. | |
42 | * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE. | |
43 | */ | |
44 | static void kasan_poison_shadow(const void *address, size_t size, u8 value) | |
45 | { | |
46 | void *shadow_start, *shadow_end; | |
47 | ||
48 | shadow_start = kasan_mem_to_shadow(address); | |
49 | shadow_end = kasan_mem_to_shadow(address + size); | |
50 | ||
51 | memset(shadow_start, value, shadow_end - shadow_start); | |
52 | } | |
53 | ||
54 | void kasan_unpoison_shadow(const void *address, size_t size) | |
55 | { | |
56 | kasan_poison_shadow(address, size, 0); | |
57 | ||
58 | if (size & KASAN_SHADOW_MASK) { | |
59 | u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size); | |
60 | *shadow = size & KASAN_SHADOW_MASK; | |
61 | } | |
62 | } | |
63 | ||
e3ae1163 MR |
64 | static void __kasan_unpoison_stack(struct task_struct *task, void *sp) |
65 | { | |
66 | void *base = task_stack_page(task); | |
67 | size_t size = sp - base; | |
68 | ||
69 | kasan_unpoison_shadow(base, size); | |
70 | } | |
71 | ||
72 | /* Unpoison the entire stack for a task. */ | |
73 | void kasan_unpoison_task_stack(struct task_struct *task) | |
74 | { | |
75 | __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE); | |
76 | } | |
77 | ||
78 | /* Unpoison the stack for the current task beyond a watermark sp value. */ | |
79 | asmlinkage void kasan_unpoison_remaining_stack(void *sp) | |
80 | { | |
81 | __kasan_unpoison_stack(current, sp); | |
82 | } | |
0b24becc AR |
83 | |
84 | /* | |
85 | * All functions below always inlined so compiler could | |
86 | * perform better optimizations in each of __asan_loadX/__assn_storeX | |
87 | * depending on memory access size X. | |
88 | */ | |
89 | ||
90 | static __always_inline bool memory_is_poisoned_1(unsigned long addr) | |
91 | { | |
92 | s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr); | |
93 | ||
94 | if (unlikely(shadow_value)) { | |
95 | s8 last_accessible_byte = addr & KASAN_SHADOW_MASK; | |
96 | return unlikely(last_accessible_byte >= shadow_value); | |
97 | } | |
98 | ||
99 | return false; | |
100 | } | |
101 | ||
102 | static __always_inline bool memory_is_poisoned_2(unsigned long addr) | |
103 | { | |
104 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); | |
105 | ||
106 | if (unlikely(*shadow_addr)) { | |
107 | if (memory_is_poisoned_1(addr + 1)) | |
108 | return true; | |
109 | ||
10f70262 XQ |
110 | /* |
111 | * If single shadow byte covers 2-byte access, we don't | |
112 | * need to do anything more. Otherwise, test the first | |
113 | * shadow byte. | |
114 | */ | |
0b24becc AR |
115 | if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0)) |
116 | return false; | |
117 | ||
118 | return unlikely(*(u8 *)shadow_addr); | |
119 | } | |
120 | ||
121 | return false; | |
122 | } | |
123 | ||
124 | static __always_inline bool memory_is_poisoned_4(unsigned long addr) | |
125 | { | |
126 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); | |
127 | ||
128 | if (unlikely(*shadow_addr)) { | |
129 | if (memory_is_poisoned_1(addr + 3)) | |
130 | return true; | |
131 | ||
10f70262 XQ |
132 | /* |
133 | * If single shadow byte covers 4-byte access, we don't | |
134 | * need to do anything more. Otherwise, test the first | |
135 | * shadow byte. | |
136 | */ | |
0b24becc AR |
137 | if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3)) |
138 | return false; | |
139 | ||
140 | return unlikely(*(u8 *)shadow_addr); | |
141 | } | |
142 | ||
143 | return false; | |
144 | } | |
145 | ||
146 | static __always_inline bool memory_is_poisoned_8(unsigned long addr) | |
147 | { | |
148 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); | |
149 | ||
150 | if (unlikely(*shadow_addr)) { | |
151 | if (memory_is_poisoned_1(addr + 7)) | |
152 | return true; | |
153 | ||
10f70262 XQ |
154 | /* |
155 | * If single shadow byte covers 8-byte access, we don't | |
156 | * need to do anything more. Otherwise, test the first | |
157 | * shadow byte. | |
158 | */ | |
159 | if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) | |
0b24becc AR |
160 | return false; |
161 | ||
162 | return unlikely(*(u8 *)shadow_addr); | |
163 | } | |
164 | ||
165 | return false; | |
166 | } | |
167 | ||
168 | static __always_inline bool memory_is_poisoned_16(unsigned long addr) | |
169 | { | |
170 | u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr); | |
171 | ||
172 | if (unlikely(*shadow_addr)) { | |
173 | u16 shadow_first_bytes = *(u16 *)shadow_addr; | |
0b24becc AR |
174 | |
175 | if (unlikely(shadow_first_bytes)) | |
176 | return true; | |
177 | ||
10f70262 XQ |
178 | /* |
179 | * If two shadow bytes covers 16-byte access, we don't | |
180 | * need to do anything more. Otherwise, test the last | |
181 | * shadow byte. | |
182 | */ | |
183 | if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) | |
0b24becc AR |
184 | return false; |
185 | ||
186 | return memory_is_poisoned_1(addr + 15); | |
187 | } | |
188 | ||
189 | return false; | |
190 | } | |
191 | ||
192 | static __always_inline unsigned long bytes_is_zero(const u8 *start, | |
193 | size_t size) | |
194 | { | |
195 | while (size) { | |
196 | if (unlikely(*start)) | |
197 | return (unsigned long)start; | |
198 | start++; | |
199 | size--; | |
200 | } | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
205 | static __always_inline unsigned long memory_is_zero(const void *start, | |
206 | const void *end) | |
207 | { | |
208 | unsigned int words; | |
209 | unsigned long ret; | |
210 | unsigned int prefix = (unsigned long)start % 8; | |
211 | ||
212 | if (end - start <= 16) | |
213 | return bytes_is_zero(start, end - start); | |
214 | ||
215 | if (prefix) { | |
216 | prefix = 8 - prefix; | |
217 | ret = bytes_is_zero(start, prefix); | |
218 | if (unlikely(ret)) | |
219 | return ret; | |
220 | start += prefix; | |
221 | } | |
222 | ||
223 | words = (end - start) / 8; | |
224 | while (words) { | |
225 | if (unlikely(*(u64 *)start)) | |
226 | return bytes_is_zero(start, 8); | |
227 | start += 8; | |
228 | words--; | |
229 | } | |
230 | ||
231 | return bytes_is_zero(start, (end - start) % 8); | |
232 | } | |
233 | ||
234 | static __always_inline bool memory_is_poisoned_n(unsigned long addr, | |
235 | size_t size) | |
236 | { | |
237 | unsigned long ret; | |
238 | ||
239 | ret = memory_is_zero(kasan_mem_to_shadow((void *)addr), | |
240 | kasan_mem_to_shadow((void *)addr + size - 1) + 1); | |
241 | ||
242 | if (unlikely(ret)) { | |
243 | unsigned long last_byte = addr + size - 1; | |
244 | s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte); | |
245 | ||
246 | if (unlikely(ret != (unsigned long)last_shadow || | |
e0d57714 | 247 | ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow))) |
0b24becc AR |
248 | return true; |
249 | } | |
250 | return false; | |
251 | } | |
252 | ||
253 | static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size) | |
254 | { | |
255 | if (__builtin_constant_p(size)) { | |
256 | switch (size) { | |
257 | case 1: | |
258 | return memory_is_poisoned_1(addr); | |
259 | case 2: | |
260 | return memory_is_poisoned_2(addr); | |
261 | case 4: | |
262 | return memory_is_poisoned_4(addr); | |
263 | case 8: | |
264 | return memory_is_poisoned_8(addr); | |
265 | case 16: | |
266 | return memory_is_poisoned_16(addr); | |
267 | default: | |
268 | BUILD_BUG(); | |
269 | } | |
270 | } | |
271 | ||
272 | return memory_is_poisoned_n(addr, size); | |
273 | } | |
274 | ||
275 | ||
276 | static __always_inline void check_memory_region(unsigned long addr, | |
277 | size_t size, bool write) | |
278 | { | |
0b24becc AR |
279 | if (unlikely(size == 0)) |
280 | return; | |
281 | ||
282 | if (unlikely((void *)addr < | |
283 | kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) { | |
e9121076 | 284 | kasan_report(addr, size, write, _RET_IP_); |
0b24becc AR |
285 | return; |
286 | } | |
287 | ||
288 | if (likely(!memory_is_poisoned(addr, size))) | |
289 | return; | |
290 | ||
291 | kasan_report(addr, size, write, _RET_IP_); | |
292 | } | |
293 | ||
393f203f AR |
294 | void __asan_loadN(unsigned long addr, size_t size); |
295 | void __asan_storeN(unsigned long addr, size_t size); | |
296 | ||
297 | #undef memset | |
298 | void *memset(void *addr, int c, size_t len) | |
299 | { | |
300 | __asan_storeN((unsigned long)addr, len); | |
301 | ||
302 | return __memset(addr, c, len); | |
303 | } | |
304 | ||
305 | #undef memmove | |
306 | void *memmove(void *dest, const void *src, size_t len) | |
307 | { | |
308 | __asan_loadN((unsigned long)src, len); | |
309 | __asan_storeN((unsigned long)dest, len); | |
310 | ||
311 | return __memmove(dest, src, len); | |
312 | } | |
313 | ||
314 | #undef memcpy | |
315 | void *memcpy(void *dest, const void *src, size_t len) | |
316 | { | |
317 | __asan_loadN((unsigned long)src, len); | |
318 | __asan_storeN((unsigned long)dest, len); | |
319 | ||
320 | return __memcpy(dest, src, len); | |
321 | } | |
322 | ||
b8c73fc2 AR |
323 | void kasan_alloc_pages(struct page *page, unsigned int order) |
324 | { | |
325 | if (likely(!PageHighMem(page))) | |
326 | kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order); | |
327 | } | |
328 | ||
329 | void kasan_free_pages(struct page *page, unsigned int order) | |
330 | { | |
331 | if (likely(!PageHighMem(page))) | |
332 | kasan_poison_shadow(page_address(page), | |
333 | PAGE_SIZE << order, | |
334 | KASAN_FREE_PAGE); | |
335 | } | |
336 | ||
0316bec2 AR |
337 | void kasan_poison_slab(struct page *page) |
338 | { | |
339 | kasan_poison_shadow(page_address(page), | |
340 | PAGE_SIZE << compound_order(page), | |
341 | KASAN_KMALLOC_REDZONE); | |
342 | } | |
343 | ||
344 | void kasan_unpoison_object_data(struct kmem_cache *cache, void *object) | |
345 | { | |
346 | kasan_unpoison_shadow(object, cache->object_size); | |
347 | } | |
348 | ||
349 | void kasan_poison_object_data(struct kmem_cache *cache, void *object) | |
350 | { | |
351 | kasan_poison_shadow(object, | |
352 | round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE), | |
353 | KASAN_KMALLOC_REDZONE); | |
354 | } | |
355 | ||
356 | void kasan_slab_alloc(struct kmem_cache *cache, void *object) | |
357 | { | |
358 | kasan_kmalloc(cache, object, cache->object_size); | |
359 | } | |
360 | ||
361 | void kasan_slab_free(struct kmem_cache *cache, void *object) | |
362 | { | |
363 | unsigned long size = cache->object_size; | |
364 | unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE); | |
365 | ||
366 | /* RCU slabs could be legally used after free within the RCU period */ | |
367 | if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU)) | |
368 | return; | |
369 | ||
370 | kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE); | |
371 | } | |
372 | ||
373 | void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size) | |
374 | { | |
375 | unsigned long redzone_start; | |
376 | unsigned long redzone_end; | |
377 | ||
378 | if (unlikely(object == NULL)) | |
379 | return; | |
380 | ||
381 | redzone_start = round_up((unsigned long)(object + size), | |
382 | KASAN_SHADOW_SCALE_SIZE); | |
383 | redzone_end = round_up((unsigned long)object + cache->object_size, | |
384 | KASAN_SHADOW_SCALE_SIZE); | |
385 | ||
386 | kasan_unpoison_shadow(object, size); | |
387 | kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, | |
388 | KASAN_KMALLOC_REDZONE); | |
389 | } | |
390 | EXPORT_SYMBOL(kasan_kmalloc); | |
391 | ||
392 | void kasan_kmalloc_large(const void *ptr, size_t size) | |
393 | { | |
394 | struct page *page; | |
395 | unsigned long redzone_start; | |
396 | unsigned long redzone_end; | |
397 | ||
398 | if (unlikely(ptr == NULL)) | |
399 | return; | |
400 | ||
401 | page = virt_to_page(ptr); | |
402 | redzone_start = round_up((unsigned long)(ptr + size), | |
403 | KASAN_SHADOW_SCALE_SIZE); | |
404 | redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page)); | |
405 | ||
406 | kasan_unpoison_shadow(ptr, size); | |
407 | kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start, | |
408 | KASAN_PAGE_REDZONE); | |
409 | } | |
410 | ||
411 | void kasan_krealloc(const void *object, size_t size) | |
412 | { | |
413 | struct page *page; | |
414 | ||
415 | if (unlikely(object == ZERO_SIZE_PTR)) | |
416 | return; | |
417 | ||
418 | page = virt_to_head_page(object); | |
419 | ||
420 | if (unlikely(!PageSlab(page))) | |
421 | kasan_kmalloc_large(object, size); | |
422 | else | |
423 | kasan_kmalloc(page->slab_cache, object, size); | |
424 | } | |
425 | ||
92393615 AR |
426 | void kasan_kfree(void *ptr) |
427 | { | |
428 | struct page *page; | |
429 | ||
430 | page = virt_to_head_page(ptr); | |
431 | ||
432 | if (unlikely(!PageSlab(page))) | |
433 | kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), | |
434 | KASAN_FREE_PAGE); | |
435 | else | |
436 | kasan_slab_free(page->slab_cache, ptr); | |
437 | } | |
438 | ||
0316bec2 AR |
439 | void kasan_kfree_large(const void *ptr) |
440 | { | |
441 | struct page *page = virt_to_page(ptr); | |
442 | ||
443 | kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page), | |
444 | KASAN_FREE_PAGE); | |
445 | } | |
446 | ||
bebf56a1 AR |
447 | int kasan_module_alloc(void *addr, size_t size) |
448 | { | |
449 | void *ret; | |
450 | size_t shadow_size; | |
451 | unsigned long shadow_start; | |
452 | ||
453 | shadow_start = (unsigned long)kasan_mem_to_shadow(addr); | |
454 | shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT, | |
455 | PAGE_SIZE); | |
456 | ||
457 | if (WARN_ON(!PAGE_ALIGNED(shadow_start))) | |
458 | return -EINVAL; | |
459 | ||
460 | ret = __vmalloc_node_range(shadow_size, 1, shadow_start, | |
461 | shadow_start + shadow_size, | |
462 | GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, | |
463 | PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE, | |
464 | __builtin_return_address(0)); | |
a5af5aa8 AR |
465 | |
466 | if (ret) { | |
467 | find_vm_area(addr)->flags |= VM_KASAN; | |
45937254 | 468 | kmemleak_ignore(ret); |
a5af5aa8 AR |
469 | return 0; |
470 | } | |
471 | ||
472 | return -ENOMEM; | |
bebf56a1 AR |
473 | } |
474 | ||
a5af5aa8 | 475 | void kasan_free_shadow(const struct vm_struct *vm) |
bebf56a1 | 476 | { |
a5af5aa8 AR |
477 | if (vm->flags & VM_KASAN) |
478 | vfree(kasan_mem_to_shadow(vm->addr)); | |
bebf56a1 AR |
479 | } |
480 | ||
481 | static void register_global(struct kasan_global *global) | |
482 | { | |
483 | size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE); | |
484 | ||
485 | kasan_unpoison_shadow(global->beg, global->size); | |
486 | ||
487 | kasan_poison_shadow(global->beg + aligned_size, | |
488 | global->size_with_redzone - aligned_size, | |
489 | KASAN_GLOBAL_REDZONE); | |
490 | } | |
491 | ||
492 | void __asan_register_globals(struct kasan_global *globals, size_t size) | |
493 | { | |
494 | int i; | |
495 | ||
496 | for (i = 0; i < size; i++) | |
497 | register_global(&globals[i]); | |
498 | } | |
499 | EXPORT_SYMBOL(__asan_register_globals); | |
500 | ||
501 | void __asan_unregister_globals(struct kasan_global *globals, size_t size) | |
502 | { | |
503 | } | |
504 | EXPORT_SYMBOL(__asan_unregister_globals); | |
505 | ||
0b24becc AR |
506 | #define DEFINE_ASAN_LOAD_STORE(size) \ |
507 | void __asan_load##size(unsigned long addr) \ | |
508 | { \ | |
509 | check_memory_region(addr, size, false); \ | |
510 | } \ | |
511 | EXPORT_SYMBOL(__asan_load##size); \ | |
512 | __alias(__asan_load##size) \ | |
513 | void __asan_load##size##_noabort(unsigned long); \ | |
514 | EXPORT_SYMBOL(__asan_load##size##_noabort); \ | |
515 | void __asan_store##size(unsigned long addr) \ | |
516 | { \ | |
517 | check_memory_region(addr, size, true); \ | |
518 | } \ | |
519 | EXPORT_SYMBOL(__asan_store##size); \ | |
520 | __alias(__asan_store##size) \ | |
521 | void __asan_store##size##_noabort(unsigned long); \ | |
522 | EXPORT_SYMBOL(__asan_store##size##_noabort) | |
523 | ||
524 | DEFINE_ASAN_LOAD_STORE(1); | |
525 | DEFINE_ASAN_LOAD_STORE(2); | |
526 | DEFINE_ASAN_LOAD_STORE(4); | |
527 | DEFINE_ASAN_LOAD_STORE(8); | |
528 | DEFINE_ASAN_LOAD_STORE(16); | |
529 | ||
530 | void __asan_loadN(unsigned long addr, size_t size) | |
531 | { | |
532 | check_memory_region(addr, size, false); | |
533 | } | |
534 | EXPORT_SYMBOL(__asan_loadN); | |
535 | ||
536 | __alias(__asan_loadN) | |
537 | void __asan_loadN_noabort(unsigned long, size_t); | |
538 | EXPORT_SYMBOL(__asan_loadN_noabort); | |
539 | ||
540 | void __asan_storeN(unsigned long addr, size_t size) | |
541 | { | |
542 | check_memory_region(addr, size, true); | |
543 | } | |
544 | EXPORT_SYMBOL(__asan_storeN); | |
545 | ||
546 | __alias(__asan_storeN) | |
547 | void __asan_storeN_noabort(unsigned long, size_t); | |
548 | EXPORT_SYMBOL(__asan_storeN_noabort); | |
549 | ||
550 | /* to shut up compiler complaints */ | |
551 | void __asan_handle_no_return(void) {} | |
552 | EXPORT_SYMBOL(__asan_handle_no_return); | |
786a8959 AR |
553 | |
554 | #ifdef CONFIG_MEMORY_HOTPLUG | |
555 | static int kasan_mem_notifier(struct notifier_block *nb, | |
556 | unsigned long action, void *data) | |
557 | { | |
558 | return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK; | |
559 | } | |
560 | ||
561 | static int __init kasan_memhotplug_init(void) | |
562 | { | |
25add7ec | 563 | pr_err("WARNING: KASAN doesn't support memory hot-add\n"); |
786a8959 AR |
564 | pr_err("Memory hot-add will be disabled\n"); |
565 | ||
566 | hotplug_memory_notifier(kasan_mem_notifier, 0); | |
567 | ||
568 | return 0; | |
569 | } | |
570 | ||
571 | module_init(kasan_memhotplug_init); | |
572 | #endif |