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/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(unsigned long addr)
 138 {
 139         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 140
 141         if (unlikely(*shadow_addr)) {
 142                 if (memory_is_poisoned_1(addr + 1))
 143                         return true;
 144
 145                 /*
 146                  * If single shadow byte covers 2-byte access, we don't
 147                  * need to do anything more. Otherwise, test the first
 148                  * shadow byte.
 149                  */
 150                 if (likely(((addr + 1) & KASAN_SHADOW_MASK) != 0))
 151                         return false;
 152
 153                 return unlikely(*(u8 *)shadow_addr);
 154         }
 155
 156         return false;
 157 }
 158
 159 static __always_inline bool memory_is_poisoned_4(unsigned long addr)
 160 {
 161         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 162
 163         if (unlikely(*shadow_addr)) {
 164                 if (memory_is_poisoned_1(addr + 3))
 165                         return true;
 166
 167                 /*
 168                  * If single shadow byte covers 4-byte access, we don't
 169                  * need to do anything more. Otherwise, test the first
 170                  * shadow byte.
 171                  */
 172                 if (likely(((addr + 3) & KASAN_SHADOW_MASK) >= 3))
 173                         return false;
 174
 175                 return unlikely(*(u8 *)shadow_addr);
 176         }
 177
 178         return false;
 179 }
 180
 181 static __always_inline bool memory_is_poisoned_8(unsigned long addr)
 182 {
 183         u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr);
 184
 185         if (unlikely(*shadow_addr)) {
 186                 if (memory_is_poisoned_1(addr + 7))
 187                         return true;
 188
 189                 /*
 190                  * If single shadow byte covers 8-byte access, we don't
 191                  * need to do anything more. Otherwise, test the first
 192                  * shadow byte.
 193                  */
 194                 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 195                         return false;
 196
 197                 return unlikely(*(u8 *)shadow_addr);
 198         }
 199
 200         return false;
 201 }
 202
 203 static __always_inline bool memory_is_poisoned_16(unsigned long addr)
 204 {
 205         u32 *shadow_addr = (u32 *)kasan_mem_to_shadow((void *)addr);
 206
 207         if (unlikely(*shadow_addr)) {
 208                 u16 shadow_first_bytes = *(u16 *)shadow_addr;
 209
 210                 if (unlikely(shadow_first_bytes))
 211                         return true;
 212
 213                 /*
 214                  * If two shadow bytes covers 16-byte access, we don't
 215                  * need to do anything more. Otherwise, test the last
 216                  * shadow byte.
 217                  */
 218                 if (likely(IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE)))
 219                         return false;
 220
 221                 return memory_is_poisoned_1(addr + 15);
 222         }
 223
 224         return false;
 225 }
 226
 227 static __always_inline unsigned long bytes_is_zero(const u8 *start,
 228                                         size_t size)
 229 {
 230         while (size) {
 231                 if (unlikely(*start))
 232                         return (unsigned long)start;
 233                 start++;
 234                 size--;
 235         }
 236
 237         return 0;
 238 }
 239
 240 static __always_inline unsigned long memory_is_zero(const void *start,
 241                                                 const void *end)
 242 {
 243         unsigned int words;
 244         unsigned long ret;
 245         unsigned int prefix = (unsigned long)start % 8;
 246
 247         if (end - start <= 16)
 248                 return bytes_is_zero(start, end - start);
 249
 250         if (prefix) {
 251                 prefix = 8 - prefix;
 252                 ret = bytes_is_zero(start, prefix);
 253                 if (unlikely(ret))
 254                         return ret;
 255                 start += prefix;
 256         }
 257
 258         words = (end - start) / 8;
 259         while (words) {
 260                 if (unlikely(*(u64 *)start))
 261                         return bytes_is_zero(start, 8);
 262                 start += 8;
 263                 words--;
 264         }
 265
 266         return bytes_is_zero(start, (end - start) % 8);
 267 }
 268
 269 static __always_inline bool memory_is_poisoned_n(unsigned long addr,
 270                                                 size_t size)
 271 {
 272         unsigned long ret;
 273
 274         ret = memory_is_zero(kasan_mem_to_shadow((void *)addr),
 275                         kasan_mem_to_shadow((void *)addr + size - 1) + 1);
 276
 277         if (unlikely(ret)) {
 278                 unsigned long last_byte = addr + size - 1;
 279                 s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte);
 280
 281                 if (unlikely(ret != (unsigned long)last_shadow ||
 282                         ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow)))
 283                         return true;
 284         }
 285         return false;
 286 }
 287
 288 static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size)
 289 {
 290         if (__builtin_constant_p(size)) {
 291                 switch (size) {
 292                 case 1:
 293                         return memory_is_poisoned_1(addr);
 294                 case 2:
 295                         return memory_is_poisoned_2(addr);
 296                 case 4:
 297                         return memory_is_poisoned_4(addr);
 298                 case 8:
 299                         return memory_is_poisoned_8(addr);
 300                 case 16:
 301                         return memory_is_poisoned_16(addr);
 302                 default:
 303                         BUILD_BUG();
 304                 }
 305         }
 306
 307         return memory_is_poisoned_n(addr, size);
 308 }
 309
 310 static __always_inline void check_memory_region_inline(unsigned long addr,
 311                                                 size_t size, bool write,
 312                                                 unsigned long ret_ip)
 313 {
 314         if (unlikely(size == 0))
 315                 return;
 316
 317         if (unlikely((void *)addr <
 318                 kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) {
 319                 kasan_report(addr, size, write, ret_ip);
 320                 return;
 321         }
 322
 323         if (likely(!memory_is_poisoned(addr, size)))
 324                 return;
 325
 326         kasan_report(addr, size, write, ret_ip);
 327 }
 328
 329 static void check_memory_region(unsigned long addr,
 330                                 size_t size, bool write,
 331                                 unsigned long ret_ip)
 332 {
 333         check_memory_region_inline(addr, size, write, ret_ip);
 334 }
 335
 336 void kasan_check_read(const void *p, unsigned int size)
 337 {
 338         check_memory_region((unsigned long)p, size, false, _RET_IP_);
 339 }
 340 EXPORT_SYMBOL(kasan_check_read);
 341
 342 void kasan_check_write(const void *p, unsigned int size)
 343 {
 344         check_memory_region((unsigned long)p, size, true, _RET_IP_);
 345 }
 346 EXPORT_SYMBOL(kasan_check_write);
 347
 348 #undef memset
 349 void *memset(void *addr, int c, size_t len)
 350 {
 351         check_memory_region((unsigned long)addr, len, true, _RET_IP_);
 352
 353         return __memset(addr, c, len);
 354 }
 355
 356 #undef memmove
 357 void *memmove(void *dest, const void *src, size_t len)
 358 {
 359         check_memory_region((unsigned long)src, len, false, _RET_IP_);
 360         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
 361
 362         return __memmove(dest, src, len);
 363 }
 364
 365 #undef memcpy
 366 void *memcpy(void *dest, const void *src, size_t len)
 367 {
 368         check_memory_region((unsigned long)src, len, false, _RET_IP_);
 369         check_memory_region((unsigned long)dest, len, true, _RET_IP_);
 370
 371         return __memcpy(dest, src, len);
 372 }
 373
 374 void kasan_alloc_pages(struct page *page, unsigned int order)
 375 {
 376         if (likely(!PageHighMem(page)))
 377                 kasan_unpoison_shadow(page_address(page), PAGE_SIZE << order);
 378 }
 379
 380 void kasan_free_pages(struct page *page, unsigned int order)
 381 {
 382         if (likely(!PageHighMem(page)))
 383                 kasan_poison_shadow(page_address(page),
 384                                 PAGE_SIZE << order,
 385                                 KASAN_FREE_PAGE);
 386 }
 387
 388 /*
 389  * Adaptive redzone policy taken from the userspace AddressSanitizer runtime.
 390  * For larger allocations larger redzones are used.
 391  */
 392 static size_t optimal_redzone(size_t object_size)
 393 {
 394         int rz =
 395                 object_size <= 64        - 16   ? 16 :
 396                 object_size <= 128       - 32   ? 32 :
 397                 object_size <= 512       - 64   ? 64 :
 398                 object_size <= 4096      - 128  ? 128 :
 399                 object_size <= (1 << 14) - 256  ? 256 :
 400                 object_size <= (1 << 15) - 512  ? 512 :
 401                 object_size <= (1 << 16) - 1024 ? 1024 : 2048;
 402         return rz;
 403 }
 404
 405 void kasan_cache_create(struct kmem_cache *cache, size_t *size,
 406                         unsigned long *flags)
 407 {
 408         int redzone_adjust;
 409         int orig_size = *size;
 410
 411         /* Add alloc meta. */
 412         cache->kasan_info.alloc_meta_offset = *size;
 413         *size += sizeof(struct kasan_alloc_meta);
 414
 415         /* Add free meta. */
 416         if (cache->flags & SLAB_TYPESAFE_BY_RCU || cache->ctor ||
 417             cache->object_size < sizeof(struct kasan_free_meta)) {
 418                 cache->kasan_info.free_meta_offset = *size;
 419                 *size += sizeof(struct kasan_free_meta);
 420         }
 421         redzone_adjust = optimal_redzone(cache->object_size) -
 422                 (*size - cache->object_size);
 423
 424         if (redzone_adjust > 0)
 425                 *size += redzone_adjust;
 426
 427         *size = min(KMALLOC_MAX_SIZE, max(*size, cache->object_size +
 428                                         optimal_redzone(cache->object_size)));
 429
 430         /*
 431          * If the metadata doesn't fit, don't enable KASAN at all.
 432          */
 433         if (*size <= cache->kasan_info.alloc_meta_offset ||
 434                         *size <= cache->kasan_info.free_meta_offset) {
 435                 cache->kasan_info.alloc_meta_offset = 0;
 436                 cache->kasan_info.free_meta_offset = 0;
 437                 *size = orig_size;
 438                 return;
 439         }
 440
 441         *flags |= SLAB_KASAN;
 442 }
 443
 444 void kasan_cache_shrink(struct kmem_cache *cache)
 445 {
 446         quarantine_remove_cache(cache);
 447 }
 448
 449 void kasan_cache_shutdown(struct kmem_cache *cache)
 450 {
 451         quarantine_remove_cache(cache);
 452 }
 453
 454 size_t kasan_metadata_size(struct kmem_cache *cache)
 455 {
 456         return (cache->kasan_info.alloc_meta_offset ?
 457                 sizeof(struct kasan_alloc_meta) : 0) +
 458                 (cache->kasan_info.free_meta_offset ?
 459                 sizeof(struct kasan_free_meta) : 0);
 460 }
 461
 462 void kasan_poison_slab(struct page *page)
 463 {
 464         kasan_poison_shadow(page_address(page),
 465                         PAGE_SIZE << compound_order(page),
 466                         KASAN_KMALLOC_REDZONE);
 467 }
 468
 469 void kasan_unpoison_object_data(struct kmem_cache *cache, void *object)
 470 {
 471         kasan_unpoison_shadow(object, cache->object_size);
 472 }
 473
 474 void kasan_poison_object_data(struct kmem_cache *cache, void *object)
 475 {
 476         kasan_poison_shadow(object,
 477                         round_up(cache->object_size, KASAN_SHADOW_SCALE_SIZE),
 478                         KASAN_KMALLOC_REDZONE);
 479 }
 480
 481 static inline int in_irqentry_text(unsigned long ptr)
 482 {
 483         return (ptr >= (unsigned long)&__irqentry_text_start &&
 484                 ptr < (unsigned long)&__irqentry_text_end) ||
 485                 (ptr >= (unsigned long)&__softirqentry_text_start &&
 486                  ptr < (unsigned long)&__softirqentry_text_end);
 487 }
 488
 489 static inline void filter_irq_stacks(struct stack_trace *trace)
 490 {
 491         int i;
 492
 493         if (!trace->nr_entries)
 494                 return;
 495         for (i = 0; i < trace->nr_entries; i++)
 496                 if (in_irqentry_text(trace->entries[i])) {
 497                         /* Include the irqentry function into the stack. */
 498                         trace->nr_entries = i + 1;
 499                         break;
 500                 }
 501 }
 502
 503 static inline depot_stack_handle_t save_stack(gfp_t flags)
 504 {
 505         unsigned long entries[KASAN_STACK_DEPTH];
 506         struct stack_trace trace = {
 507                 .nr_entries = 0,
 508                 .entries = entries,
 509                 .max_entries = KASAN_STACK_DEPTH,
 510                 .skip = 0
 511         };
 512
 513         save_stack_trace(&trace);
 514         filter_irq_stacks(&trace);
 515         if (trace.nr_entries != 0 &&
 516             trace.entries[trace.nr_entries-1] == ULONG_MAX)
 517                 trace.nr_entries--;
 518
 519         return depot_save_stack(&trace, flags);
 520 }
 521
 522 static inline void set_track(struct kasan_track *track, gfp_t flags)
 523 {
 524         track->pid = current->pid;
 525         track->stack = save_stack(flags);
 526 }
 527
 528 struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache,
 529                                         const void *object)
 530 {
 531         BUILD_BUG_ON(sizeof(struct kasan_alloc_meta) > 32);
 532         return (void *)object + cache->kasan_info.alloc_meta_offset;
 533 }
 534
 535 struct kasan_free_meta *get_free_info(struct kmem_cache *cache,
 536                                       const void *object)
 537 {
 538         BUILD_BUG_ON(sizeof(struct kasan_free_meta) > 32);
 539         return (void *)object + cache->kasan_info.free_meta_offset;
 540 }
 541
 542 void kasan_init_slab_obj(struct kmem_cache *cache, const void *object)
 543 {
 544         struct kasan_alloc_meta *alloc_info;
 545
 546         if (!(cache->flags & SLAB_KASAN))
 547                 return;
 548
 549         alloc_info = get_alloc_info(cache, object);
 550         __memset(alloc_info, 0, sizeof(*alloc_info));
 551 }
 552
 553 void kasan_slab_alloc(struct kmem_cache *cache, void *object, gfp_t flags)
 554 {
 555         kasan_kmalloc(cache, object, cache->object_size, flags);
 556 }
 557
 558 static void kasan_poison_slab_free(struct kmem_cache *cache, void *object)
 559 {
 560         unsigned long size = cache->object_size;
 561         unsigned long rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE);
 562
 563         /* RCU slabs could be legally used after free within the RCU period */
 564         if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
 565                 return;
 566
 567         kasan_poison_shadow(object, rounded_up_size, KASAN_KMALLOC_FREE);
 568 }
 569
 570 bool kasan_slab_free(struct kmem_cache *cache, void *object)
 571 {
 572         s8 shadow_byte;
 573
 574         /* RCU slabs could be legally used after free within the RCU period */
 575         if (unlikely(cache->flags & SLAB_TYPESAFE_BY_RCU))
 576                 return false;
 577
 578         shadow_byte = READ_ONCE(*(s8 *)kasan_mem_to_shadow(object));
 579         if (shadow_byte < 0 || shadow_byte >= KASAN_SHADOW_SCALE_SIZE) {
 580                 kasan_report_double_free(cache, object,
 581                                 __builtin_return_address(1));
 582                 return true;
 583         }
 584
 585         kasan_poison_slab_free(cache, object);
 586
 587         if (unlikely(!(cache->flags & SLAB_KASAN)))
 588                 return false;
 589
 590         set_track(&get_alloc_info(cache, object)->free_track, GFP_NOWAIT);
 591         quarantine_put(get_free_info(cache, object), cache);
 592         return true;
 593 }
 594
 595 void kasan_kmalloc(struct kmem_cache *cache, const void *object, size_t size,
 596                    gfp_t flags)
 597 {
 598         unsigned long redzone_start;
 599         unsigned long redzone_end;
 600
 601         if (gfpflags_allow_blocking(flags))
 602                 quarantine_reduce();
 603
 604         if (unlikely(object == NULL))
 605                 return;
 606
 607         redzone_start = round_up((unsigned long)(object + size),
 608                                 KASAN_SHADOW_SCALE_SIZE);
 609         redzone_end = round_up((unsigned long)object + cache->object_size,
 610                                 KASAN_SHADOW_SCALE_SIZE);
 611
 612         kasan_unpoison_shadow(object, size);
 613         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 614                 KASAN_KMALLOC_REDZONE);
 615
 616         if (cache->flags & SLAB_KASAN)
 617                 set_track(&get_alloc_info(cache, object)->alloc_track, flags);
 618 }
 619 EXPORT_SYMBOL(kasan_kmalloc);
 620
 621 void kasan_kmalloc_large(const void *ptr, size_t size, gfp_t flags)
 622 {
 623         struct page *page;
 624         unsigned long redzone_start;
 625         unsigned long redzone_end;
 626
 627         if (gfpflags_allow_blocking(flags))
 628                 quarantine_reduce();
 629
 630         if (unlikely(ptr == NULL))
 631                 return;
 632
 633         page = virt_to_page(ptr);
 634         redzone_start = round_up((unsigned long)(ptr + size),
 635                                 KASAN_SHADOW_SCALE_SIZE);
 636         redzone_end = (unsigned long)ptr + (PAGE_SIZE << compound_order(page));
 637
 638         kasan_unpoison_shadow(ptr, size);
 639         kasan_poison_shadow((void *)redzone_start, redzone_end - redzone_start,
 640                 KASAN_PAGE_REDZONE);
 641 }
 642
 643 void kasan_krealloc(const void *object, size_t size, gfp_t flags)
 644 {
 645         struct page *page;
 646
 647         if (unlikely(object == ZERO_SIZE_PTR))
 648                 return;
 649
 650         page = virt_to_head_page(object);
 651
 652         if (unlikely(!PageSlab(page)))
 653                 kasan_kmalloc_large(object, size, flags);
 654         else
 655                 kasan_kmalloc(page->slab_cache, object, size, flags);
 656 }
 657
 658 void kasan_poison_kfree(void *ptr)
 659 {
 660         struct page *page;
 661
 662         page = virt_to_head_page(ptr);
 663
 664         if (unlikely(!PageSlab(page)))
 665                 kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 666                                 KASAN_FREE_PAGE);
 667         else
 668                 kasan_poison_slab_free(page->slab_cache, ptr);
 669 }
 670
 671 void kasan_kfree_large(const void *ptr)
 672 {
 673         struct page *page = virt_to_page(ptr);
 674
 675         kasan_poison_shadow(ptr, PAGE_SIZE << compound_order(page),
 676                         KASAN_FREE_PAGE);
 677 }
 678
 679 int kasan_module_alloc(void *addr, size_t size)
 680 {
 681         void *ret;
 682         size_t shadow_size;
 683         unsigned long shadow_start;
 684
 685         shadow_start = (unsigned long)kasan_mem_to_shadow(addr);
 686         shadow_size = round_up(size >> KASAN_SHADOW_SCALE_SHIFT,
 687                         PAGE_SIZE);
 688
 689         if (WARN_ON(!PAGE_ALIGNED(shadow_start)))
 690                 return -EINVAL;
 691
 692         ret = __vmalloc_node_range(shadow_size, 1, shadow_start,
 693                         shadow_start + shadow_size,
 694                         GFP_KERNEL | __GFP_ZERO,
 695                         PAGE_KERNEL, VM_NO_GUARD, NUMA_NO_NODE,
 696                         __builtin_return_address(0));
 697
 698         if (ret) {
 699                 find_vm_area(addr)->flags |= VM_KASAN;
 700                 kmemleak_ignore(ret);
 701                 return 0;
 702         }
 703
 704         return -ENOMEM;
 705 }
 706
 707 void kasan_free_shadow(const struct vm_struct *vm)
 708 {
 709         if (vm->flags & VM_KASAN)
 710                 vfree(kasan_mem_to_shadow(vm->addr));
 711 }
 712
 713 static void register_global(struct kasan_global *global)
 714 {
 715         size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE);
 716
 717         kasan_unpoison_shadow(global->beg, global->size);
 718
 719         kasan_poison_shadow(global->beg + aligned_size,
 720                 global->size_with_redzone - aligned_size,
 721                 KASAN_GLOBAL_REDZONE);
 722 }
 723
 724 void __asan_register_globals(struct kasan_global *globals, size_t size)
 725 {
 726         int i;
 727
 728         for (i = 0; i < size; i++)
 729                 register_global(&globals[i]);
 730 }
 731 EXPORT_SYMBOL(__asan_register_globals);
 732
 733 void __asan_unregister_globals(struct kasan_global *globals, size_t size)
 734 {
 735 }
 736 EXPORT_SYMBOL(__asan_unregister_globals);
 737
 738 #define DEFINE_ASAN_LOAD_STORE(size)                                    \
 739         void __asan_load##size(unsigned long addr)                      \
 740         {                                                               \
 741                 check_memory_region_inline(addr, size, false, _RET_IP_);\
 742         }                                                               \
 743         EXPORT_SYMBOL(__asan_load##size);                               \
 744         __alias(__asan_load##size)                                      \
 745         void __asan_load##size##_noabort(unsigned long);                \
 746         EXPORT_SYMBOL(__asan_load##size##_noabort);                     \
 747         void __asan_store##size(unsigned long addr)                     \
 748         {                                                               \
 749                 check_memory_region_inline(addr, size, true, _RET_IP_); \
 750         }                                                               \
 751         EXPORT_SYMBOL(__asan_store##size);                              \
 752         __alias(__asan_store##size)                                     \
 753         void __asan_store##size##_noabort(unsigned long);               \
 754         EXPORT_SYMBOL(__asan_store##size##_noabort)
 755
 756 DEFINE_ASAN_LOAD_STORE(1);
 757 DEFINE_ASAN_LOAD_STORE(2);
 758 DEFINE_ASAN_LOAD_STORE(4);
 759 DEFINE_ASAN_LOAD_STORE(8);
 760 DEFINE_ASAN_LOAD_STORE(16);
 761
 762 void __asan_loadN(unsigned long addr, size_t size)
 763 {
 764         check_memory_region(addr, size, false, _RET_IP_);
 765 }
 766 EXPORT_SYMBOL(__asan_loadN);
 767
 768 __alias(__asan_loadN)
 769 void __asan_loadN_noabort(unsigned long, size_t);
 770 EXPORT_SYMBOL(__asan_loadN_noabort);
 771
 772 void __asan_storeN(unsigned long addr, size_t size)
 773 {
 774         check_memory_region(addr, size, true, _RET_IP_);
 775 }
 776 EXPORT_SYMBOL(__asan_storeN);
 777
 778 __alias(__asan_storeN)
 779 void __asan_storeN_noabort(unsigned long, size_t);
 780 EXPORT_SYMBOL(__asan_storeN_noabort);
 781
 782 /* to shut up compiler complaints */
 783 void __asan_handle_no_return(void) {}
 784 EXPORT_SYMBOL(__asan_handle_no_return);
 785
 786 /* Emitted by compiler to poison large objects when they go out of scope. */
 787 void __asan_poison_stack_memory(const void *addr, size_t size)
 788 {
 789         /*
 790          * Addr is KASAN_SHADOW_SCALE_SIZE-aligned and the object is surrounded
 791          * by redzones, so we simply round up size to simplify logic.
 792          */
 793         kasan_poison_shadow(addr, round_up(size, KASAN_SHADOW_SCALE_SIZE),
 794                             KASAN_USE_AFTER_SCOPE);
 795 }
 796 EXPORT_SYMBOL(__asan_poison_stack_memory);
 797
 798 /* Emitted by compiler to unpoison large objects when they go into scope. */
 799 void __asan_unpoison_stack_memory(const void *addr, size_t size)
 800 {
 801         kasan_unpoison_shadow(addr, size);
 802 }
 803 EXPORT_SYMBOL(__asan_unpoison_stack_memory);
 804
 805 #ifdef CONFIG_MEMORY_HOTPLUG
 806 static int kasan_mem_notifier(struct notifier_block *nb,
 807                         unsigned long action, void *data)
 808 {
 809         return (action == MEM_GOING_ONLINE) ? NOTIFY_BAD : NOTIFY_OK;
 810 }
 811
 812 static int __init kasan_memhotplug_init(void)
 813 {
 814         pr_info("WARNING: KASAN doesn't support memory hot-add\n");
 815         pr_info("Memory hot-add will be disabled\n");
 816
 817         hotplug_memory_notifier(kasan_mem_notifier, 0);
 818
 819         return 0;
 820 }
 821
 822 module_init(kasan_memhotplug_init);
 823 #endif