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 <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/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/slab.h>
  33 #include <linux/stacktrace.h>
  34 #include <linux/string.h>
  35 #include <linux/types.h>
  36 #include <linux/vmalloc.h>
  37 #include <linux/bug.h>
  38
  39 #include "kasan.h"
  40 #include "../slab.h"
  41
  42 /*
  43  * Poisons the shadow memory for 'size' bytes starting from 'addr'.
  44  * Memory addresses should be aligned to KASAN_SHADOW_SCALE_SIZE.
  45  */
  46 static void kasan_poison_shadow(const void *address, size_t size, u8 value)
  47 {
  48         void *shadow_start, *shadow_end;
  49
  50         shadow_start = kasan_mem_to_shadow(address);
  51         shadow_end = kasan_mem_to_shadow(address + size);
  52
  53         memset(shadow_start, value, shadow_end - shadow_start);
  54 }
  55
  56 void kasan_unpoison_shadow(const void *address, size_t size)
  57 {
  58         kasan_poison_shadow(address, size, 0);
  59
  60         if (size & KASAN_SHADOW_MASK) {
  61                 u8 *shadow = (u8 *)kasan_mem_to_shadow(address + size);
  62                 *shadow = size & KASAN_SHADOW_MASK;
  63         }
  64 }
  65
  66 static void __kasan_unpoison_stack(struct task_struct *task, const void *sp)
  67 {
  68         void *base = task_stack_page(task);
  69         size_t size = sp - base;
  70
  71         kasan_unpoison_shadow(base, size);
  72 }
  73
  74 /* Unpoison the entire stack for a task. */
  75 void kasan_unpoison_task_stack(struct task_struct *task)
  76 {
  77         __kasan_unpoison_stack(task, task_stack_page(task) + THREAD_SIZE);
  78 }
  79
  80 /* Unpoison the stack for the current task beyond a watermark sp value. */
  81 asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
  82 {
  83         /*
  84          * Calculate the task stack base address.  Avoid using 'current'
  85          * because this function is called by early resume code which hasn't
  86          * yet set up the percpu register (%gs).
  87          */
  88         void *base = (void *)((unsigned long)watermark & ~(THREAD_SIZE - 1));
  89
  90         kasan_unpoison_shadow(base, watermark - base);
  91 }
  92
  93 /*
  94  * Clear all poison for the region between the current SP and a provided
  95  * watermark value, as is sometimes required prior to hand-crafted asm function
  96  * returns in the middle of functions.
  97  */
  98 void kasan_unpoison_stack_above_sp_to(const void *watermark)
  99 {
 100         const void *sp = __builtin_frame_address(0);
 101         size_t size = watermark - sp;
 102
 103         if (WARN_ON(sp > watermark))
 104                 return;
 105         kasan_unpoison_shadow(sp, size);
 106 }
 107
 108 /*
 109  * All functions below always inlined so compiler could
 110  * perform better optimizations in each of __asan_loadX/__assn_storeX
 111  * depending on memory access size X.
 112  */
 113
 114 static __always_inline bool memory_is_poisoned_1(unsigned long addr)
 115 {
 116         s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr);
 117
 118         if (unlikely(shadow_value)) {
 119                 s8 last_accessible_byte = addr & KASAN_SHADOW_MASK;
 120                 return unlikely(last_accessible_byte >= shadow_value);
 121         }
 122
 123         return false;
 124 }
 125
 126 static __always_inline bool memory_is_poisoned_2(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 + 1))
 132                         return true;
 133
 134                 /*
 135                  * If single shadow byte covers 2-byte access, we don't
 136                  * need to do anything more. Otherwise, test the first
 137                  * shadow byte.
 138                  */
 139                 if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
 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_4(unsigned long addr)
 149 {
 150         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 151
 152         if (unlikely(*shadow_addr)) {
 153                 if (memory_is_poisoned_1(addr + 3))
 154                         return true;
 155
 156                 /*
 157                  * If single shadow byte covers 4-byte access, we don't
 158                  * need to do anything more. Otherwise, test the first
 159                  * shadow byte.
 160                  */
 161                 if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
 162                         return false;
 163
 164                 return unlikely(*(u8 *)shadow_addr);
 165         }
 166
 167         return false;
 168 }
 169
 170 static __always_inline bool memory_is_poisoned_8(unsigned long addr)
 171 {
 172         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 173
 174         if (unlikely(*shadow_addr)) {
 175                 if (memory_is_poisoned_1(addr + 7))
 176                         return true;
 177
 178                 /*
 179                  * If single shadow byte covers 8-byte access, we don't
 180                  * need to do anything more. Otherwise, test the first
 181                  * shadow byte.
 182                  */
 183                 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 184                         return false;
 185
 186                 return unlikely(*(u8 *)shadow_addr);
 187         }
 188
 189         return false;
 190 }
 191
 192 static __always_inline bool memory_is_poisoned_16(unsigned long addr)
 193 {
 194         u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr);
 195
 196         if (unlikely(*shadow_addr)) {
 197                 u16 shadow_first_bytes = *(u16 *)shadow_addr;
 198
 199                 if (unlikely(shadow_first_bytes))
 200                         return true;
 201
 202                 /*
 203                  * If two shadow bytes covers 16-byte access, we don't
 204                  * need to do anything more. Otherwise, test the last
 205                  * shadow byte.
 206                  */
 207                 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 208                         return false;
 209
 210                 return memory_is_poisoned_1(addr + 15);
 211         }
 212
 213         return false;
 214 }
 215
 216 static __always_inline unsigned long bytes_is_zero(const u8 *start,
 217                                         size_t size)
 218 {
 219         while (size) {
 220                 if (unlikely(*start))
 221                         return (unsigned long)start;
 222                 start++;
 223                 size--;
 224         }
 225
 226         return 0;
 227 }
 228
 229 static __always_inline unsigned long memory_is_zero(const void *start,
 230                                                 const void *end)
 231 {
 232         unsigned int words;
 233         unsigned long ret;
 234         unsigned int prefix = (unsigned long)start % 8;
 235
 236         if (end - start <= 16)
 237                 return bytes_is_zero(start, end - start);
 238
 239         if (prefix) {
 240                 prefix = 8 - prefix;
 241                 ret = bytes_is_zero(start, prefix);
 242                 if (unlikely(ret))
 243                         return ret;
 244                 start += prefix;
 245         }
 246
 247         words = (end - start) / 8;
 248         while (words) {
 249                 if (unlikely(*(u64 *)start))
 250                         return bytes_is_zero(start, 8);
 251                 start += 8;
 252                 words--;
 253         }
 254
 255         return bytes_is_zero(start, (end - start) % 8);
 256 }
 257
 258 static __always_inline bool memory_is_poisoned_n(unsigned long addr,
 259                                                 size_t size)
 260 {
 261         unsigned long ret;
 262
 263         ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
 264                         kasan_mem_to_shadow((void *)addr + size - 1) + 1);
 265
 266         if (unlikely(ret)) {
 267                 unsigned long last_byte = addr + size - 1;
 268                 s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
 269
 270                 if (unlikely(ret != (unsigned long)last_shadow ||
 271                         ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
 272                         return true;
 273         }
 274         return false;
 275 }
 276
 277 static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
 278 {
 279         if (__builtin_constant_p(size)) {
 280                 switch (size) {
 281                 case 1:
 282                         return memory_is_poisoned_1(addr);
 283                 case 2:
 284                         return memory_is_poisoned_2(addr);
 285                 case 4:
 286                         return memory_is_poisoned_4(addr);
 287                 case 8:
 288                         return memory_is_poisoned_8(addr);
 289                 case 16:
 290                         return memory_is_poisoned_16(addr);
 291                 default:
 292                         BUILD_BUG();
 293                 }
 294         }
 295
 296         return memory_is_poisoned_n(addr, size);
 297 }
 298
 299 static __always_inline void check_memory_region_inline(unsigned long addr,
 300                                                 size_t size, bool write,
 301                                                 unsigned long ret_ip)
 302 {
 303         if (unlikely(size == 0))
 304                 return;
 305
 306         if (unlikely((void *)addr <
 307                 kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
 308                 kasan_report(addr, size, write, ret_ip);
 309                 return;
 310         }
 311
 312         if (likely(!memory_is_poisoned(addr, size)))
 313                 return;
 314
 315         kasan_report(addr, size, write, ret_ip);
 316 }
 317
 318 static void check_memory_region(unsigned long addr,
 319                                 size_t size, bool write,
 320                                 unsigned long ret_ip)
 321 {
 322         check_memory_region_inline(addr, size, write, ret_ip);
 323 }
 324
 325 void kasan_check_read(const void *p, unsigned int size)
 326 {
 327         check_memory_region((unsigned long)p, size, false, _RET_IP_);
 328 }
 329 EXPORT_SYMBOL(kasan_check_read);
 330
 331 void kasan_check_write(const void *p, unsigned int size)
 332 {
 333         check_memory_region((unsigned long)p, size, true, _RET_IP_);
 334 }
 335 EXPORT_SYMBOL(kasan_check_write);
 336
 337 #undef memset
 338 void *memset(void *addr, int c, size_t len)
 339 {
 340         check_memory_region((unsigned long)addr, len, true, _RET_IP_);
 341
 342         return __memset(addr, c, len);
 343 }
 344
 345 #undef memmove
 346 void *memmove(void *dest, const void *src, size_t len)
 347 {
 348         check_memory_region((unsigned long)src, len, false, _RET_IP_);
 349         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
 350
 351         return __memmove(dest, src, len);
 352 }
 353
 354 #undef memcpy
 355 void *memcpy(void *dest, const void *src, size_t len)
 356 {
 357         check_memory_region((unsigned long)src, len, false, _RET_IP_);
 358         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
 359
 360         return __memcpy(dest, src, len);
 361 }
 362
 363 void kasan_alloc_pages(struct page *page, unsigned int order)
 364 {
 365         if (likely(!PageHighMem(page)))
 366                 kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
 367 }
 368
 369 void kasan_free_pages(struct page *page, unsigned int order)
 370 {
 371         if (likely(!PageHighMem(page)))
 372                 kasan_poison_shadow(page_address(page),
 373                                 PAGE_SIZE << order,
 374                                 KASAN_FREE_PAGE);
 375 }
 376
 377 /*
 378  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
 379  * For larger allocations larger redzones are used.
 380  */
 381 static size_t optimal_redzone(size_t object_size)
 382 {
 383         int rz =
 384                 object_size <= 64        - 16   ? 16 :
 385                 object_size <= 128       - 32   ? 32 :
 386                 object_size <= 512       - 64   ? 64 :
 387                 object_size <= 4096      - 128  ? 128 :
 388                 object_size <= (1 << 14) - 256  ? 256 :
 389                 object_size <= (1 << 15) - 512  ? 512 :
 390                 object_size <= (1 << 16) - 1024 ? 1024 : 2048;
 391         return rz;
 392 }
 393
 394 void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 395                         unsigned long *flags)
 396 {
 397         int redzone_adjust;
 398         int orig_size = *size;
 399
 400         /* Add alloc meta. */
 401         cache->kasan_info.alloc_meta_offset = *size;
 402         *size += sizeof(struct kasan_alloc_meta);
 403
 404         /* Add free meta. */
 405         if (cache->flags & SLAB_DESTROY_BY_RCU || cache->ctor ||
 406             cache->object_size < sizeof(struct kasan_free_meta)) {
 407                 cache->kasan_info.free_meta_offset = *size;
 408                 *size += sizeof(struct kasan_free_meta);
 409         }
 410         redzone_adjust = optimal_redzone(cache->object_size) -
 411                 (*size - cache->object_size);
 412
 413         if (redzone_adjust > 0)
 414                 *size += redzone_adjust;
 415
 416         *size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
 417                                         optimal_redzone(cache->object_size)));
 418
 419         /*
 420          * If the metadata doesn't fit, don't enable KASAN at all.
 421          */
 422         if (*size <= cache->kasan_info.alloc_meta_offset ||
 423                         *size <= cache->kasan_info.free_meta_offset) {
 424                 cache->kasan_info.alloc_meta_offset = 0;
 425                 cache->kasan_info.free_meta_offset = 0;
 426                 *size = orig_size;
 427                 return;
 428         }
 429
 430         *flags |= SLAB_KASAN;
 431 }
 432
 433 void kasan_cache_shrink(struct kmem_cache *cache)
 434 {
 435         quarantine_remove_cache(cache);
 436 }
 437
 438 void kasan_cache_destroy(struct kmem_cache *cache)
 439 {
 440         quarantine_remove_cache(cache);
 441 }
 442
 443 size_t kasan_metadata_size(struct kmem_cache *cache)
 444 {
 445         return (cache->kasan_info.alloc_meta_offset ?
 446                 sizeof(struct kasan_alloc_meta) : 0) +
 447                 (cache->kasan_info.free_meta_offset ?
 448                 sizeof(struct kasan_free_meta) : 0);
 449 }
 450
 451 void kasan_poison_slab(struct page *page)
 452 {
 453         kasan_poison_shadow(page_address(page),
 454                         PAGE_SIZE << compound_order(page),
 455                         KASAN_KMALLOC_REDZONE);
 456 }
 457
 458 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 459 {
 460         kasan_unpoison_shadow(object, cache->object_size);
 461 }
 462
 463 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 464 {
 465         kasan_poison_shadow(object,
 466                         round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
 467                         KASAN_KMALLOC_REDZONE);
 468 }
 469
 470 static inline int in_irqentry_text(unsigned long ptr)
 471 {
 472         return (ptr >= (unsigned long)&__irqentry_text_start &&
 473                 ptr < (unsigned long)&__irqentry_text_end) ||
 474                 (ptr >= (unsigned long)&__softirqentry_text_start &&
 475                  ptr < (unsigned long)&__softirqentry_text_end);
 476 }
 477
 478 static inline void filter_irq_stacks(struct stack_trace *trace)
 479 {
 480         int i;
 481
 482         if (!trace->nr_entries)
 483                 return;
 484         for (i = 0; i < trace->nr_entries; i++)
 485                 if (in_irqentry_text(trace->entries[i])) {
 486                         /* Include the irqentry function into the stack. */
 487                         trace->nr_entries = i + 1;
 488                         break;
 489                 }
 490 }
 491
 492 static inline depot_stack_handle_t save_stack(gfp_t flags)
 493 {
 494         unsigned long entries[KASAN_STACK_DEPTH];
 495         struct stack_trace trace = {
 496                 .nr_entries = 0,
 497                 .entries = entries,
 498                 .max_entries = KASAN_STACK_DEPTH,
 499                 .skip = 0
 500         };
 501
 502         save_stack_trace(&trace);
 503         filter_irq_stacks(&trace);
 504         if (trace.nr_entries != 0 &&
 505             trace.entries[trace.nr_entries-1] == ULONG_MAX)
 506                 trace.nr_entries--;
 507
 508         return depot_save_stack(&trace, flags);
 509 }
 510
 511 static inline void set_track(struct kasan_track *track, gfp_t flags)
 512 {
 513         track->pid = current->pid;
 514         track->stack = save_stack(flags);
 515 }
 516
 517 struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 518                                         const void *object)
 519 {
 520         BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
 521         return (void *)object + cache->kasan_info.alloc_meta_offset;
 522 }
 523
 524 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 525                                       const void *object)
 526 {
 527         BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
 528         return (void *)object + cache->kasan_info.free_meta_offset;
 529 }
 530
 531 void kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
 532 {
 533         struct kasan_alloc_meta *alloc_info;
 534
 535         if (!(cache->flags & SLAB_KASAN))
 536                 return;
 537
 538         alloc_info = get_alloc_info(cache, object);
 539         __memset(alloc_info, 0, sizeof(*alloc_info));
 540 }
 541
 542 void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
 543 {
 544         kasan_kmalloc(cache, object, cache->object_size, flags);
 545 }
 546
 547 static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
 548 {
 549         unsigned long size = cache->object_size;
 550         unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
 551
 552         /* RCU slabs could be legally used after free within the RCU period */
 553         if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
 554                 return;
 555
 556         kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
 557 }
 558
 559 bool kasan_slab_free(struct kmem_cache *cache, void *object)
 560 {
 561         s8 shadow_byte;
 562
 563         /* RCU slabs could be legally used after free within the RCU period */
 564         if (unlikely(cache->flags & SLAB_DESTROY_BY_RCU))
 565                 return false;
 566
 567         shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
 568         if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
 569                 kasan_report_double_free(cache, object, shadow_byte);
 570                 return true;
 571         }
 572
 573         kasan_poison_slab_free(cache, object);
 574
 575         if (unlikely(!(cache->flags & SLAB_KASAN)))
 576                 return false;
 577
 578         set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
 579         quarantine_put(get_free_info(cache, object), cache);
 580         return true;
 581 }
 582
 583 void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 584                    gfp_t flags)
 585 {
 586         unsigned long redzone_start;
 587         unsigned long redzone_end;
 588
 589         if (gfpflags_allow_blocking(flags))
 590                 quarantine_reduce();
 591
 592         if (unlikely(object == NULL))
 593                 return;
 594
 595         redzone_start = round_up((unsigned long)(object + size),
 596                                 KASAN_SHADOW_SCALE_SIZE);
 597         redzone_end = round_up((unsigned long)object + cache->object_size,
 598                                 KASAN_SHADOW_SCALE_SIZE);
 599
 600         kasan_unpoison_shadow(object, size);
 601         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 602                 KASAN_KMALLOC_REDZONE);
 603
 604         if (cache->flags & SLAB_KASAN)
 605                 set_track(&get_alloc_info(cache, object)->alloc_track, flags);
 606 }
 607 EXPORT_SYMBOL(kasan_kmalloc);
 608
 609 void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
 610 {
 611         struct page *page;
 612         unsigned long redzone_start;
 613         unsigned long redzone_end;
 614
 615         if (gfpflags_allow_blocking(flags))
 616                 quarantine_reduce();
 617
 618         if (unlikely(ptr == NULL))
 619                 return;
 620
 621         page = virt_to_page(ptr);
 622         redzone_start = round_up((unsigned long)(ptr + size),
 623                                 KASAN_SHADOW_SCALE_SIZE);
 624         redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
 625
 626         kasan_unpoison_shadow(ptr, size);
 627         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 628                 KASAN_PAGE_REDZONE);
 629 }
 630
 631 void kasan_krealloc(const void *object, size_t size, gfp_t flags)
 632 {
 633         struct page *page;
 634
 635         if (unlikely(object == ZERO_SIZE_PTR))
 636                 return;
 637
 638         page = virt_to_head_page(object);
 639
 640         if (unlikely(!PageSlab(page)))
 641                 kasan_kmalloc_large(object, size, flags);
 642         else
 643                 kasan_kmalloc(page->slab_cache, object, size, flags);
 644 }
 645
 646 void kasan_poison_kfree(void *ptr)
 647 {
 648         struct page *page;
 649
 650         page = virt_to_head_page(ptr);
 651
 652         if (unlikely(!PageSlab(page)))
 653                 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 654                                 KASAN_FREE_PAGE);
 655         else
 656                 kasan_poison_slab_free(page->slab_cache, ptr);
 657 }
 658
 659 void kasan_kfree_large(const void *ptr)
 660 {
 661         struct page *page = virt_to_page(ptr);
 662
 663         kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 664                         KASAN_FREE_PAGE);
 665 }
 666
 667 int kasan_module_alloc(void *addr, size_t size)
 668 {
 669         void *ret;
 670         size_t scaled_size;
 671         size_t shadow_size;
 672         unsigned long shadow_start;
 673
 674         shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
 675         scaled_size = (size + KASAN_SHADOW_MASK) >> KASAN_SHADOW_SCALE_SHIFT;
 676         shadow_size = round_up(scaled_size, PAGE_SIZE);
 677
 678         if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
 679                 return -EINVAL;
 680
 681         ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
 682                         shadow_start + shadow_size,
 683                         GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
 684                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
 685                         __builtin_return_address(0));
 686
 687         if (ret) {
 688                 find_vm_area(addr)->flags |= VM_KASAN;
 689                 kmemleak_ignore(ret);
 690                 return 0;
 691         }
 692
 693         return -ENOMEM;
 694 }
 695
 696 void kasan_free_shadow(const struct vm_struct *vm)
 697 {
 698         if (vm->flags & VM_KASAN)
 699                 vfree(kasan_mem_to_shadow(vm->addr));
 700 }
 701
 702 static void register_global(struct kasan_global *global)
 703 {
 704         size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
 705
 706         kasan_unpoison_shadow(global->beg, global->size);
 707
 708         kasan_poison_shadow(global->beg + aligned_size,
 709                 global->size_with_redzone - aligned_size,
 710                 KASAN_GLOBAL_REDZONE);
 711 }
 712
 713 void __asan_register_globals(struct kasan_global *globals, size_t size)
 714 {
 715         int i;
 716
 717         for (i = 0; i < size; i++)
 718                 register_global(&globals[i]);
 719 }
 720 EXPORT_SYMBOL(__asan_register_globals);
 721
 722 void __asan_unregister_globals(struct kasan_global *globals, size_t size)
 723 {
 724 }
 725 EXPORT_SYMBOL(__asan_unregister_globals);
 726
 727 #define DEFINE_ASAN_LOAD_STORE(size)                                    \
 728         void __asan_load##size(unsigned long addr)                      \
 729         {                                                               \
 730                 check_memory_region_inline(addr, size, false, _RET_IP_);\
 731         }                                                               \
 732         EXPORT_SYMBOL(__asan_load##size);                               \
 733         __alias(__asan_load##size)                                      \
 734         void __asan_load##size##_noabort(unsigned long);                \
 735         EXPORT_SYMBOL(__asan_load##size##_noabort);                     \
 736         void __asan_store##size(unsigned long addr)                     \
 737         {                                                               \
 738                 check_memory_region_inline(addr, size, true, _RET_IP_); \
 739         }                                                               \
 740         EXPORT_SYMBOL(__asan_store##size);                              \
 741         __alias(__asan_store##size)                                     \
 742         void __asan_store##size##_noabort(unsigned long);               \
 743         EXPORT_SYMBOL(__asan_store##size##_noabort)
 744
 745 DEFINE_ASAN_LOAD_STORE(1);
 746 DEFINE_ASAN_LOAD_STORE(2);
 747 DEFINE_ASAN_LOAD_STORE(4);
 748 DEFINE_ASAN_LOAD_STORE(8);
 749 DEFINE_ASAN_LOAD_STORE(16);
 750
 751 void __asan_loadN(unsigned long addr, size_t size)
 752 {
 753         check_memory_region(addr, size, false, _RET_IP_);
 754 }
 755 EXPORT_SYMBOL(__asan_loadN);
 756
 757 __alias(__asan_loadN)
 758 void __asan_loadN_noabort(unsigned long, size_t);
 759 EXPORT_SYMBOL(__asan_loadN_noabort);
 760
 761 void __asan_storeN(unsigned long addr, size_t size)
 762 {
 763         check_memory_region(addr, size, true, _RET_IP_);
 764 }
 765 EXPORT_SYMBOL(__asan_storeN);
 766
 767 __alias(__asan_storeN)
 768 void __asan_storeN_noabort(unsigned long, size_t);
 769 EXPORT_SYMBOL(__asan_storeN_noabort);
 770
 771 /* to shut up compiler complaints */
 772 void __asan_handle_no_return(void) {}
 773 EXPORT_SYMBOL(__asan_handle_no_return);
 774
 775 /* Emitted by compiler to poison large objects when they go out of scope. */
 776 void __asan_poison_stack_memory(const void *addr, size_t size)
 777 {
 778         /*
 779          * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded
 780          * by redzones, so we simply round up size to simplify logic.
 781          */
 782         kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE),
 783                             KASAN_USE_AFTER_SCOPE);
 784 }
 785 EXPORT_SYMBOL(__asan_poison_stack_memory);
 786
 787 /* Emitted by compiler to unpoison large objects when they go into scope. */
 788 void __asan_unpoison_stack_memory(const void *addr, size_t size)
 789 {
 790         kasan_unpoison_shadow(addr, size);
 791 }
 792 EXPORT_SYMBOL(__asan_unpoison_stack_memory);
 793
 794 #ifdef CONFIG_MEMORY_HOTPLUG
 795 static int kasan_mem_notifier(struct notifier_block *nb,
 796                         unsigned long action, void *data)
 797 {
 798         return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
 799 }
 800
 801 static int __init kasan_memhotplug_init(void)
 802 {
 803         pr_info("WARNING: KASAN doesn't support memory hot-add\n");
 804         pr_info("Memory hot-add will be disabled\n");
 805
 806         hotplug_memory_notifier(kasan_mem_notifier, 0);
 807
 808         return 0;
 809 }
 810
 811 core_initcall(kasan_memhotplug_init);
 812 #endif