bc0e68f7dc756104ff47005a4f9403af7e08fe4e
[sfrench/cifs-2.6.git] / mm / kasan / kasan.c
1 /*
2  * This file contains shadow memory manipulation code.
3  *
4  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
5  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
6  *
7  * Some code borrowed from https://github.com/xairy/kasan-prototype by
8  *        Andrey Konovalov <andreyknvl@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/interrupt.h>
21 #include <linux/init.h>
22 #include <linux/kasan.h>
23 #include <linux/kernel.h>
24 #include <linux/kmemleak.h>
25 #include <linux/linkage.h>
26 #include <linux/memblock.h>
27 #include <linux/memory.h>
28 #include <linux/mm.h>
29 #include <linux/module.h>
30 #include <linux/printk.h>
31 #include <linux/sched.h>
32 #include <linux/sched/task_stack.h>
33 #include <linux/slab.h>
34 #include <linux/stacktrace.h>
35 #include <linux/string.h>
36 #include <linux/types.h>
37 #include <linux/vmalloc.h>
38 #include <linux/bug.h>
39
40 #include "kasan.h"
41 #include "../slab.h"
42
43 void kasan_enable_current(void)
44 {
45         current->kasan_depth++;
46 }
47
48 void kasan_disable_current(void)
49 {
50         current->kasan_depth--;
51 }
52
53 /*
54  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
55  * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
56  */
57 static void kasan_poison_shadow(const void *address, size_t size, u8 value)
58 {
59         void *shadow_start, *shadow_end;
60
61         shadow_start = kasan_mem_to_shadow(address);
62         shadow_end = kasan_mem_to_shadow(address + size);
63
64         memset(shadow_start, value, shadow_end - shadow_start);
65 }
66
67 void kasan_unpoison_shadow(const void *address, size_t size)
68 {
69         kasan_poison_shadow(address, size, 0);
70
71         if (size & KASAN_SHADOW_MASK) {
72                 u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
73                 *shadow = size & KASAN_SHADOW_MASK;
74         }
75 }
76
77 static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
78 {
79         void *base = task_stack_page(task);
80         size_t size = sp - base;
81
82         kasan_unpoison_shadow(base, size);
83 }
84
85 /* Unpoison the entire stack for a task. */
86 void kasan_unpoison_task_stack(struct task_struct *task)
87 {
88         __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
89 }
90
91 /* Unpoison the stack for the current task beyond a watermark sp value. */
92 asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
93 {
94         /*
95          * Calculate the task stack base address.  Avoid using 'current'
96          * because this function is called by early resume code which hasn't
97          * yet set up the percpu register (%gs).
98          */
99         void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
100
101         kasan_unpoison_shadow(base, watermark - base);
102 }
103
104 /*
105  * Clear all poison for the region between the current SP and a provided
106  * watermark value, as is sometimes required prior to hand-crafted asm function
107  * returns in the middle of functions.
108  */
109 void kasan_unpoison_stack_above_sp_to(const void *watermark)
110 {
111         const void *sp = __builtin_frame_address(0);
112         size_t size = watermark - sp;
113
114         if (WARN_ON(sp > watermark))
115                 return;
116         kasan_unpoison_shadow(sp, size);
117 }
118
119 /*
120  * All functions below always inlined so compiler could
121  * perform better optimizations in each of __asan_loadX/__assn_storeX
122  * depending on memory access size X.
123  */
124
125 static __always_inline bool memory_is_poisoned_1(unsigned long addr)
126 {
127         s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
128
129         if (unlikely(shadow_value)) {
130                 s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
131                 return unlikely(last_accessible_byte >= shadow_value);
132         }
133
134         return false;
135 }
136
137 static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr,
138                                                 unsigned long size)
139 {
140         u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr);
141
142         /*
143          * Access crosses 8(shadow size)-byte boundary. Such access maps
144          * into 2 shadow bytes, so we need to check them both.
145          */
146         if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1))
147                 return *shadow_addr || memory_is_poisoned_1(addr + size - 1);
148
149         return memory_is_poisoned_1(addr + size - 1);
150 }
151
152 static __always_inline bool memory_is_poisoned_16(unsigned long addr)
153 {
154         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
155
156         /* Unaligned 16-bytes access maps into 3 shadow bytes. */
157         if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
158                 return *shadow_addr || memory_is_poisoned_1(addr + 15);
159
160         return *shadow_addr;
161 }
162
163 static __always_inline unsigned long bytes_is_nonzero(const u8 *start,
164                                         size_t size)
165 {
166         while (size) {
167                 if (unlikely(*start))
168                         return (unsigned long)start;
169                 start++;
170                 size--;
171         }
172
173         return 0;
174 }
175
176 static __always_inline unsigned long memory_is_nonzero(const void *start,
177                                                 const void *end)
178 {
179         unsigned int words;
180         unsigned long ret;
181         unsigned int prefix = (unsigned long)start % 8;
182
183         if (end - start <= 16)
184                 return bytes_is_nonzero(start, end - start);
185
186         if (prefix) {
187                 prefix = 8 - prefix;
188                 ret = bytes_is_nonzero(start, prefix);
189                 if (unlikely(ret))
190                         return ret;
191                 start += prefix;
192         }
193
194         words = (end - start) / 8;
195         while (words) {
196                 if (unlikely(*(u64 *)start))
197                         return bytes_is_nonzero(start, 8);
198                 start += 8;
199                 words--;
200         }
201
202         return bytes_is_nonzero(start, (end - start) % 8);
203 }
204
205 static __always_inline bool memory_is_poisoned_n(unsigned long addr,
206                                                 size_t size)
207 {
208         unsigned long ret;
209
210         ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr),
211                         kasan_mem_to_shadow((void *)addr + size - 1) + 1);
212
213         if (unlikely(ret)) {
214                 unsigned long last_byte = addr + size - 1;
215                 s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
216
217                 if (unlikely(ret != (unsigned long)last_shadow ||
218                         ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
219                         return true;
220         }
221         return false;
222 }
223
224 static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
225 {
226         if (__builtin_constant_p(size)) {
227                 switch (size) {
228                 case 1:
229                         return memory_is_poisoned_1(addr);
230                 case 2:
231                 case 4:
232                 case 8:
233                         return memory_is_poisoned_2_4_8(addr, size);
234                 case 16:
235                         return memory_is_poisoned_16(addr);
236                 default:
237                         BUILD_BUG();
238                 }
239         }
240
241         return memory_is_poisoned_n(addr, size);
242 }
243
244 static __always_inline void check_memory_region_inline(unsigned long addr,
245                                                 size_t size, bool write,
246                                                 unsigned long ret_ip)
247 {
248         if (unlikely(size == 0))
249                 return;
250
251         if (unlikely((void *)addr <
252                 kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
253                 kasan_report(addr, size, write, ret_ip);
254                 return;
255         }
256
257         if (likely(!memory_is_poisoned(addr, size)))
258                 return;
259
260         kasan_report(addr, size, write, ret_ip);
261 }
262
263 static void check_memory_region(unsigned long addr,
264                                 size_t size, bool write,
265                                 unsigned long ret_ip)
266 {
267         check_memory_region_inline(addr, size, write, ret_ip);
268 }
269
270 void kasan_check_read(const volatile void *p, unsigned int size)
271 {
272         check_memory_region((unsigned long)p, size, false, _RET_IP_);
273 }
274 EXPORT_SYMBOL(kasan_check_read);
275
276 void kasan_check_write(const volatile void *p, unsigned int size)
277 {
278         check_memory_region((unsigned long)p, size, true, _RET_IP_);
279 }
280 EXPORT_SYMBOL(kasan_check_write);
281
282 #undef memset
283 void *memset(void *addr, int c, size_t len)
284 {
285         check_memory_region((unsigned long)addr, len, true, _RET_IP_);
286
287         return __memset(addr, c, len);
288 }
289
290 #undef memmove
291 void *memmove(void *dest, const void *src, size_t len)
292 {
293         check_memory_region((unsigned long)src, len, false, _RET_IP_);
294         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
295
296         return __memmove(dest, src, len);
297 }
298
299 #undef memcpy
300 void *memcpy(void *dest, const void *src, size_t len)
301 {
302         check_memory_region((unsigned long)src, len, false, _RET_IP_);
303         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
304
305         return __memcpy(dest, src, len);
306 }
307
308 void kasan_alloc_pages(struct page *page, unsigned int order)
309 {
310         if (likely(!PageHighMem(page)))
311                 kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
312 }
313
314 void kasan_free_pages(struct page *page, unsigned int order)
315 {
316         if (likely(!PageHighMem(page)))
317                 kasan_poison_shadow(page_address(page),
318                                 PAGE_SIZE << order,
319                                 KASAN_FREE_PAGE);
320 }
321
322 /*
323  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
324  * For larger allocations larger redzones are used.
325  */
326 static unsigned int optimal_redzone(unsigned int object_size)
327 {
328         return
329                 object_size <= 64        - 16   ? 16 :
330                 object_size <= 128       - 32   ? 32 :
331                 object_size <= 512       - 64   ? 64 :
332                 object_size <= 4096      - 128  ? 128 :
333                 object_size <= (1 << 14) - 256  ? 256 :
334                 object_size <= (1 << 15) - 512  ? 512 :
335                 object_size <= (1 << 16) - 1024 ? 1024 : 2048;
336 }
337
338 void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
339                         slab_flags_t *flags)
340 {
341         unsigned int orig_size = *size;
342         int redzone_adjust;
343
344         /* Add alloc meta. */
345         cache->kasan_info.alloc_meta_offset = *size;
346         *size += sizeof(struct kasan_alloc_meta);
347
348         /* Add free meta. */
349         if (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor ||
350             cache->object_size < sizeof(struct kasan_free_meta)) {
351                 cache->kasan_info.free_meta_offset = *size;
352                 *size += sizeof(struct kasan_free_meta);
353         }
354         redzone_adjust = optimal_redzone(cache->object_size) -
355                 (*size - cache->object_size);
356
357         if (redzone_adjust > 0)
358                 *size += redzone_adjust;
359
360         *size = min_t(unsigned int, KMALLOC_MAX_SIZE,
361                         max(*size, cache->object_size +
362                                         optimal_redzone(cache->object_size)));
363
364         /*
365          * If the metadata doesn't fit, don't enable KASAN at all.
366          */
367         if (*size <= cache->kasan_info.alloc_meta_offset ||
368                         *size <= cache->kasan_info.free_meta_offset) {
369                 cache->kasan_info.alloc_meta_offset = 0;
370                 cache->kasan_info.free_meta_offset = 0;
371                 *size = orig_size;
372                 return;
373         }
374
375         *flags |= SLAB_KASAN;
376 }
377
378 void kasan_cache_shrink(struct kmem_cache *cache)
379 {
380         quarantine_remove_cache(cache);
381 }
382
383 void kasan_cache_shutdown(struct kmem_cache *cache)
384 {
385         if (!__kmem_cache_empty(cache))
386                 quarantine_remove_cache(cache);
387 }
388
389 size_t kasan_metadata_size(struct kmem_cache *cache)
390 {
391         return (cache->kasan_info.alloc_meta_offset ?
392                 sizeof(struct kasan_alloc_meta) : 0) +
393                 (cache->kasan_info.free_meta_offset ?
394                 sizeof(struct kasan_free_meta) : 0);
395 }
396
397 void kasan_poison_slab(struct page *page)
398 {
399         kasan_poison_shadow(page_address(page),
400                         PAGE_SIZE << compound_order(page),
401                         KASAN_KMALLOC_REDZONE);
402 }
403
404 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
405 {
406         kasan_unpoison_shadow(object, cache->object_size);
407 }
408
409 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
410 {
411         kasan_poison_shadow(object,
412                         round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
413                         KASAN_KMALLOC_REDZONE);
414 }
415
416 static inline int in_irqentry_text(unsigned long ptr)
417 {
418         return (ptr >= (unsigned long)&__irqentry_text_start &&
419                 ptr < (unsigned long)&__irqentry_text_end) ||
420                 (ptr >= (unsigned long)&__softirqentry_text_start &&
421                  ptr < (unsigned long)&__softirqentry_text_end);
422 }
423
424 static inline void filter_irq_stacks(struct stack_trace *trace)
425 {
426         int i;
427
428         if (!trace->nr_entries)
429                 return;
430         for (i = 0; i < trace->nr_entries; i++)
431                 if (in_irqentry_text(trace->entries[i])) {
432                         /* Include the irqentry function into the stack. */
433                         trace->nr_entries = i + 1;
434                         break;
435                 }
436 }
437
438 static inline depot_stack_handle_t save_stack(gfp_t flags)
439 {
440         unsigned long entries[KASAN_STACK_DEPTH];
441         struct stack_trace trace = {
442                 .nr_entries = 0,
443                 .entries = entries,
444                 .max_entries = KASAN_STACK_DEPTH,
445                 .skip = 0
446         };
447
448         save_stack_trace(&trace);
449         filter_irq_stacks(&trace);
450         if (trace.nr_entries != 0 &&
451             trace.entries[trace.nr_entries-1] == ULONG_MAX)
452                 trace.nr_entries--;
453
454         return depot_save_stack(&trace, flags);
455 }
456
457 static inline void set_track(struct kasan_track *track, gfp_t flags)
458 {
459         track->pid = current->pid;
460         track->stack = save_stack(flags);
461 }
462
463 struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
464                                         const void *object)
465 {
466         BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
467         return (void *)object + cache->kasan_info.alloc_meta_offset;
468 }
469
470 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
471                                       const void *object)
472 {
473         BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
474         return (void *)object + cache->kasan_info.free_meta_offset;
475 }
476
477 void kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
478 {
479         struct kasan_alloc_meta *alloc_info;
480
481         if (!(cache->flags & SLAB_KASAN))
482                 return;
483
484         alloc_info = get_alloc_info(cache, object);
485         __memset(alloc_info, 0, sizeof(*alloc_info));
486 }
487
488 void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
489 {
490         kasan_kmalloc(cache, object, cache->object_size, flags);
491 }
492
493 static bool __kasan_slab_free(struct kmem_cache *cache, void *object,
494                               unsigned long ip, bool quarantine)
495 {
496         s8 shadow_byte;
497         unsigned long rounded_up_size;
498
499         if (unlikely(nearest_obj(cache, virt_to_head_page(object), object) !=
500             object)) {
501                 kasan_report_invalid_free(object, ip);
502                 return true;
503         }
504
505         /* RCU slabs could be legally used after free within the RCU period */
506         if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
507                 return false;
508
509         shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
510         if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
511                 kasan_report_invalid_free(object, ip);
512                 return true;
513         }
514
515         rounded_up_size = round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE);
516         kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
517
518         if (!quarantine || unlikely(!(cache->flags & SLAB_KASAN)))
519                 return false;
520
521         set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
522         quarantine_put(get_free_info(cache, object), cache);
523         return true;
524 }
525
526 bool kasan_slab_free(struct kmem_cache *cache, void *object, unsigned long ip)
527 {
528         return __kasan_slab_free(cache, object, ip, true);
529 }
530
531 void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
532                    gfp_t flags)
533 {
534         unsigned long redzone_start;
535         unsigned long redzone_end;
536
537         if (gfpflags_allow_blocking(flags))
538                 quarantine_reduce();
539
540         if (unlikely(object == NULL))
541                 return;
542
543         redzone_start = round_up((unsigned long)(object + size),
544                                 KASAN_SHADOW_SCALE_SIZE);
545         redzone_end = round_up((unsigned long)object + cache->object_size,
546                                 KASAN_SHADOW_SCALE_SIZE);
547
548         kasan_unpoison_shadow(object, size);
549         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
550                 KASAN_KMALLOC_REDZONE);
551
552         if (cache->flags & SLAB_KASAN)
553                 set_track(&get_alloc_info(cache, object)->alloc_track, flags);
554 }
555 EXPORT_SYMBOL(kasan_kmalloc);
556
557 void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
558 {
559         struct page *page;
560         unsigned long redzone_start;
561         unsigned long redzone_end;
562
563         if (gfpflags_allow_blocking(flags))
564                 quarantine_reduce();
565
566         if (unlikely(ptr == NULL))
567                 return;
568
569         page = virt_to_page(ptr);
570         redzone_start = round_up((unsigned long)(ptr + size),
571                                 KASAN_SHADOW_SCALE_SIZE);
572         redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
573
574         kasan_unpoison_shadow(ptr, size);
575         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
576                 KASAN_PAGE_REDZONE);
577 }
578
579 void kasan_krealloc(const void *object, size_t size, gfp_t flags)
580 {
581         struct page *page;
582
583         if (unlikely(object == ZERO_SIZE_PTR))
584                 return;
585
586         page = virt_to_head_page(object);
587
588         if (unlikely(!PageSlab(page)))
589                 kasan_kmalloc_large(object, size, flags);
590         else
591                 kasan_kmalloc(page->slab_cache, object, size, flags);
592 }
593
594 void kasan_poison_kfree(void *ptr, unsigned long ip)
595 {
596         struct page *page;
597
598         page = virt_to_head_page(ptr);
599
600         if (unlikely(!PageSlab(page))) {
601                 if (ptr != page_address(page)) {
602                         kasan_report_invalid_free(ptr, ip);
603                         return;
604                 }
605                 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
606                                 KASAN_FREE_PAGE);
607         } else {
608                 __kasan_slab_free(page->slab_cache, ptr, ip, false);
609         }
610 }
611
612 void kasan_kfree_large(void *ptr, unsigned long ip)
613 {
614         if (ptr != page_address(virt_to_head_page(ptr)))
615                 kasan_report_invalid_free(ptr, ip);
616         /* The object will be poisoned by page_alloc. */
617 }
618
619 int kasan_module_alloc(void *addr, size_t size)
620 {
621         void *ret;
622         size_t shadow_size;
623         unsigned long shadow_start;
624
625         shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
626         shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
627                         PAGE_SIZE);
628
629         if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
630                 return -EINVAL;
631
632         ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
633                         shadow_start + shadow_size,
634                         GFP_KERNEL | __GFP_ZERO,
635                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
636                         __builtin_return_address(0));
637
638         if (ret) {
639                 find_vm_area(addr)->flags |= VM_KASAN;
640                 kmemleak_ignore(ret);
641                 return 0;
642         }
643
644         return -ENOMEM;
645 }
646
647 void kasan_free_shadow(const struct vm_struct *vm)
648 {
649         if (vm->flags & VM_KASAN)
650                 vfree(kasan_mem_to_shadow(vm->addr));
651 }
652
653 static void register_global(struct kasan_global *global)
654 {
655         size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
656
657         kasan_unpoison_shadow(global->beg, global->size);
658
659         kasan_poison_shadow(global->beg + aligned_size,
660                 global->size_with_redzone - aligned_size,
661                 KASAN_GLOBAL_REDZONE);
662 }
663
664 void __asan_register_globals(struct kasan_global *globals, size_t size)
665 {
666         int i;
667
668         for (i = 0; i < size; i++)
669                 register_global(&globals[i]);
670 }
671 EXPORT_SYMBOL(__asan_register_globals);
672
673 void __asan_unregister_globals(struct kasan_global *globals, size_t size)
674 {
675 }
676 EXPORT_SYMBOL(__asan_unregister_globals);
677
678 #define DEFINE_ASAN_LOAD_STORE(size)                                    \
679         void __asan_load##size(unsigned long addr)                      \
680         {                                                               \
681                 check_memory_region_inline(addr, size, false, _RET_IP_);\
682         }                                                               \
683         EXPORT_SYMBOL(__asan_load##size);                               \
684         __alias(__asan_load##size)                                      \
685         void __asan_load##size##_noabort(unsigned long);                \
686         EXPORT_SYMBOL(__asan_load##size##_noabort);                     \
687         void __asan_store##size(unsigned long addr)                     \
688         {                                                               \
689                 check_memory_region_inline(addr, size, true, _RET_IP_); \
690         }                                                               \
691         EXPORT_SYMBOL(__asan_store##size);                              \
692         __alias(__asan_store##size)                                     \
693         void __asan_store##size##_noabort(unsigned long);               \
694         EXPORT_SYMBOL(__asan_store##size##_noabort)
695
696 DEFINE_ASAN_LOAD_STORE(1);
697 DEFINE_ASAN_LOAD_STORE(2);
698 DEFINE_ASAN_LOAD_STORE(4);
699 DEFINE_ASAN_LOAD_STORE(8);
700 DEFINE_ASAN_LOAD_STORE(16);
701
702 void __asan_loadN(unsigned long addr, size_t size)
703 {
704         check_memory_region(addr, size, false, _RET_IP_);
705 }
706 EXPORT_SYMBOL(__asan_loadN);
707
708 __alias(__asan_loadN)
709 void __asan_loadN_noabort(unsigned long, size_t);
710 EXPORT_SYMBOL(__asan_loadN_noabort);
711
712 void __asan_storeN(unsigned long addr, size_t size)
713 {
714         check_memory_region(addr, size, true, _RET_IP_);
715 }
716 EXPORT_SYMBOL(__asan_storeN);
717
718 __alias(__asan_storeN)
719 void __asan_storeN_noabort(unsigned long, size_t);
720 EXPORT_SYMBOL(__asan_storeN_noabort);
721
722 /* to shut up compiler complaints */
723 void __asan_handle_no_return(void) {}
724 EXPORT_SYMBOL(__asan_handle_no_return);
725
726 /* Emitted by compiler to poison large objects when they go out of scope. */
727 void __asan_poison_stack_memory(const void *addr, size_t size)
728 {
729         /*
730          * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded
731          * by redzones, so we simply round up size to simplify logic.
732          */
733         kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE),
734                             KASAN_USE_AFTER_SCOPE);
735 }
736 EXPORT_SYMBOL(__asan_poison_stack_memory);
737
738 /* Emitted by compiler to unpoison large objects when they go into scope. */
739 void __asan_unpoison_stack_memory(const void *addr, size_t size)
740 {
741         kasan_unpoison_shadow(addr, size);
742 }
743 EXPORT_SYMBOL(__asan_unpoison_stack_memory);
744
745 /* Emitted by compiler to poison alloca()ed objects. */
746 void __asan_alloca_poison(unsigned long addr, size_t size)
747 {
748         size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
749         size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) -
750                         rounded_up_size;
751         size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE);
752
753         const void *left_redzone = (const void *)(addr -
754                         KASAN_ALLOCA_REDZONE_SIZE);
755         const void *right_redzone = (const void *)(addr + rounded_up_size);
756
757         WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE));
758
759         kasan_unpoison_shadow((const void *)(addr + rounded_down_size),
760                               size - rounded_down_size);
761         kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE,
762                         KASAN_ALLOCA_LEFT);
763         kasan_poison_shadow(right_redzone,
764                         padding_size + KASAN_ALLOCA_REDZONE_SIZE,
765                         KASAN_ALLOCA_RIGHT);
766 }
767 EXPORT_SYMBOL(__asan_alloca_poison);
768
769 /* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */
770 void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom)
771 {
772         if (unlikely(!stack_top || stack_top > stack_bottom))
773                 return;
774
775         kasan_unpoison_shadow(stack_top, stack_bottom - stack_top);
776 }
777 EXPORT_SYMBOL(__asan_allocas_unpoison);
778
779 /* Emitted by the compiler to [un]poison local variables. */
780 #define DEFINE_ASAN_SET_SHADOW(byte) \
781         void __asan_set_shadow_##byte(const void *addr, size_t size)    \
782         {                                                               \
783                 __memset((void *)addr, 0x##byte, size);                 \
784         }                                                               \
785         EXPORT_SYMBOL(__asan_set_shadow_##byte)
786
787 DEFINE_ASAN_SET_SHADOW(00);
788 DEFINE_ASAN_SET_SHADOW(f1);
789 DEFINE_ASAN_SET_SHADOW(f2);
790 DEFINE_ASAN_SET_SHADOW(f3);
791 DEFINE_ASAN_SET_SHADOW(f5);
792 DEFINE_ASAN_SET_SHADOW(f8);
793
794 #ifdef CONFIG_MEMORY_HOTPLUG
795 static int __meminit kasan_mem_notifier(struct notifier_block *nb,
796                         unsigned long action, void *data)
797 {
798         struct memory_notify *mem_data = data;
799         unsigned long nr_shadow_pages, start_kaddr, shadow_start;
800         unsigned long shadow_end, shadow_size;
801
802         nr_shadow_pages = mem_data->nr_pages >> KASAN_SHADOW_SCALE_SHIFT;
803         start_kaddr = (unsigned long)pfn_to_kaddr(mem_data->start_pfn);
804         shadow_start = (unsigned long)kasan_mem_to_shadow((void *)start_kaddr);
805         shadow_size = nr_shadow_pages << PAGE_SHIFT;
806         shadow_end = shadow_start + shadow_size;
807
808         if (WARN_ON(mem_data->nr_pages % KASAN_SHADOW_SCALE_SIZE) ||
809                 WARN_ON(start_kaddr % (KASAN_SHADOW_SCALE_SIZE << PAGE_SHIFT)))
810                 return NOTIFY_BAD;
811
812         switch (action) {
813         case MEM_GOING_ONLINE: {
814                 void *ret;
815
816                 ret = __vmalloc_node_range(shadow_size, PAGE_SIZE, shadow_start,
817                                         shadow_end, GFP_KERNEL,
818                                         PAGE_KERNEL, VM_NO_GUARD,
819                                         pfn_to_nid(mem_data->start_pfn),
820                                         __builtin_return_address(0));
821                 if (!ret)
822                         return NOTIFY_BAD;
823
824                 kmemleak_ignore(ret);
825                 return NOTIFY_OK;
826         }
827         case MEM_OFFLINE:
828                 vfree((void *)shadow_start);
829         }
830
831         return NOTIFY_OK;
832 }
833
834 static int __init kasan_memhotplug_init(void)
835 {
836         hotplug_memory_notifier(kasan_mem_notifier, 0);
837
838         return 0;
839 }
840
841 module_init(kasan_memhotplug_init);
842 #endif