libsanitizer/asan/asan_allocator2.cc

   1 //===-- asan_allocator2.cc ------------------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is a part of AddressSanitizer, an address sanity checker.
   9 //
  10 // Implementation of ASan's memory allocator, 2-nd version.
  11 // This variant uses the allocator from sanitizer_common, i.e. the one shared
  12 // with ThreadSanitizer and MemorySanitizer.
  13 //
  14 //===----------------------------------------------------------------------===//
  15 #include "asan_allocator.h"
  16
  17 #include "asan_mapping.h"
  18 #include "asan_poisoning.h"
  19 #include "asan_report.h"
  20 #include "asan_stack.h"
  21 #include "asan_thread.h"
  22 #include "sanitizer_common/sanitizer_allocator_interface.h"
  23 #include "sanitizer_common/sanitizer_flags.h"
  24 #include "sanitizer_common/sanitizer_internal_defs.h"
  25 #include "sanitizer_common/sanitizer_list.h"
  26 #include "sanitizer_common/sanitizer_stackdepot.h"
  27 #include "sanitizer_common/sanitizer_quarantine.h"
  28 #include "lsan/lsan_common.h"
  29
  30 namespace __asan {
  31
  32 void AsanMapUnmapCallback::OnMap(uptr p, uptr size) const {
  33   PoisonShadow(p, size, kAsanHeapLeftRedzoneMagic);
  34   // Statistics.
  35   AsanStats &thread_stats = GetCurrentThreadStats();
  36   thread_stats.mmaps++;
  37   thread_stats.mmaped += size;
  38 }
  39 void AsanMapUnmapCallback::OnUnmap(uptr p, uptr size) const {
  40   PoisonShadow(p, size, 0);
  41   // We are about to unmap a chunk of user memory.
  42   // Mark the corresponding shadow memory as not needed.
  43   FlushUnneededASanShadowMemory(p, size);
  44   // Statistics.
  45   AsanStats &thread_stats = GetCurrentThreadStats();
  46   thread_stats.munmaps++;
  47   thread_stats.munmaped += size;
  48 }
  49
  50 // We can not use THREADLOCAL because it is not supported on some of the
  51 // platforms we care about (OSX 10.6, Android).
  52 // static THREADLOCAL AllocatorCache cache;
  53 AllocatorCache *GetAllocatorCache(AsanThreadLocalMallocStorage *ms) {
  54   CHECK(ms);
  55   return &ms->allocator2_cache;
  56 }
  57
  58 static Allocator allocator;
  59
  60 static const uptr kMaxAllowedMallocSize =
  61   FIRST_32_SECOND_64(3UL << 30, 64UL << 30);
  62
  63 static const uptr kMaxThreadLocalQuarantine =
  64   FIRST_32_SECOND_64(1 << 18, 1 << 20);
  65
  66 // Every chunk of memory allocated by this allocator can be in one of 3 states:
  67 // CHUNK_AVAILABLE: the chunk is in the free list and ready to be allocated.
  68 // CHUNK_ALLOCATED: the chunk is allocated and not yet freed.
  69 // CHUNK_QUARANTINE: the chunk was freed and put into quarantine zone.
  70 enum {
  71   CHUNK_AVAILABLE  = 0,  // 0 is the default value even if we didn't set it.
  72   CHUNK_ALLOCATED  = 2,
  73   CHUNK_QUARANTINE = 3
  74 };
  75
  76 // Valid redzone sizes are 16, 32, 64, ... 2048, so we encode them in 3 bits.
  77 // We use adaptive redzones: for larger allocation larger redzones are used.
  78 static u32 RZLog2Size(u32 rz_log) {
  79   CHECK_LT(rz_log, 8);
  80   return 16 << rz_log;
  81 }
  82
  83 static u32 RZSize2Log(u32 rz_size) {
  84   CHECK_GE(rz_size, 16);
  85   CHECK_LE(rz_size, 2048);
  86   CHECK(IsPowerOfTwo(rz_size));
  87   u32 res = Log2(rz_size) - 4;
  88   CHECK_EQ(rz_size, RZLog2Size(res));
  89   return res;
  90 }
  91
  92 static uptr ComputeRZLog(uptr user_requested_size) {
  93   u32 rz_log =
  94     user_requested_size <= 64        - 16   ? 0 :
  95     user_requested_size <= 128       - 32   ? 1 :
  96     user_requested_size <= 512       - 64   ? 2 :
  97     user_requested_size <= 4096      - 128  ? 3 :
  98     user_requested_size <= (1 << 14) - 256  ? 4 :
  99     user_requested_size <= (1 << 15) - 512  ? 5 :
 100     user_requested_size <= (1 << 16) - 1024 ? 6 : 7;
 101   return Min(Max(rz_log, RZSize2Log(flags()->redzone)),
 102              RZSize2Log(flags()->max_redzone));
 103 }
 104
 105 // The memory chunk allocated from the underlying allocator looks like this:
 106 // L L L L L L H H U U U U U U R R
 107 //   L -- left redzone words (0 or more bytes)
 108 //   H -- ChunkHeader (16 bytes), which is also a part of the left redzone.
 109 //   U -- user memory.
 110 //   R -- right redzone (0 or more bytes)
 111 // ChunkBase consists of ChunkHeader and other bytes that overlap with user
 112 // memory.
 113
 114 // If the left redzone is greater than the ChunkHeader size we store a magic
 115 // value in the first uptr word of the memory block and store the address of
 116 // ChunkBase in the next uptr.
 117 // M B L L L L L L L L L  H H U U U U U U
 118 //   |                    ^
 119 //   ---------------------|
 120 //   M -- magic value kAllocBegMagic
 121 //   B -- address of ChunkHeader pointing to the first 'H'
 122 static const uptr kAllocBegMagic = 0xCC6E96B9;
 123
 124 struct ChunkHeader {
 125   // 1-st 8 bytes.
 126   u32 chunk_state       : 8;  // Must be first.
 127   u32 alloc_tid         : 24;
 128
 129   u32 free_tid          : 24;
 130   u32 from_memalign     : 1;
 131   u32 alloc_type        : 2;
 132   u32 rz_log            : 3;
 133   u32 lsan_tag          : 2;
 134   // 2-nd 8 bytes
 135   // This field is used for small sizes. For large sizes it is equal to
 136   // SizeClassMap::kMaxSize and the actual size is stored in the
 137   // SecondaryAllocator's metadata.
 138   u32 user_requested_size;
 139   u32 alloc_context_id;
 140 };
 141
 142 struct ChunkBase : ChunkHeader {
 143   // Header2, intersects with user memory.
 144   u32 free_context_id;
 145 };
 146
 147 static const uptr kChunkHeaderSize = sizeof(ChunkHeader);
 148 static const uptr kChunkHeader2Size = sizeof(ChunkBase) - kChunkHeaderSize;
 149 COMPILER_CHECK(kChunkHeaderSize == 16);
 150 COMPILER_CHECK(kChunkHeader2Size <= 16);
 151
 152 struct AsanChunk: ChunkBase {
 153   uptr Beg() { return reinterpret_cast<uptr>(this) + kChunkHeaderSize; }
 154   uptr UsedSize(bool locked_version = false) {
 155     if (user_requested_size != SizeClassMap::kMaxSize)
 156       return user_requested_size;
 157     return *reinterpret_cast<uptr *>(
 158                 allocator.GetMetaData(AllocBeg(locked_version)));
 159   }
 160   void *AllocBeg(bool locked_version = false) {
 161     if (from_memalign) {
 162       if (locked_version)
 163         return allocator.GetBlockBeginFastLocked(
 164             reinterpret_cast<void *>(this));
 165       return allocator.GetBlockBegin(reinterpret_cast<void *>(this));
 166     }
 167     return reinterpret_cast<void*>(Beg() - RZLog2Size(rz_log));
 168   }
 169   bool AddrIsInside(uptr addr, bool locked_version = false) {
 170     return (addr >= Beg()) && (addr < Beg() + UsedSize(locked_version));
 171   }
 172 };
 173
 174 bool AsanChunkView::IsValid() {
 175   return chunk_ != 0 && chunk_->chunk_state != CHUNK_AVAILABLE;
 176 }
 177 uptr AsanChunkView::Beg() { return chunk_->Beg(); }
 178 uptr AsanChunkView::End() { return Beg() + UsedSize(); }
 179 uptr AsanChunkView::UsedSize() { return chunk_->UsedSize(); }
 180 uptr AsanChunkView::AllocTid() { return chunk_->alloc_tid; }
 181 uptr AsanChunkView::FreeTid() { return chunk_->free_tid; }
 182
 183 static StackTrace GetStackTraceFromId(u32 id) {
 184   CHECK(id);
 185   StackTrace res = StackDepotGet(id);
 186   CHECK(res.trace);
 187   return res;
 188 }
 189
 190 StackTrace AsanChunkView::GetAllocStack() {
 191   return GetStackTraceFromId(chunk_->alloc_context_id);
 192 }
 193
 194 StackTrace AsanChunkView::GetFreeStack() {
 195   return GetStackTraceFromId(chunk_->free_context_id);
 196 }
 197
 198 struct QuarantineCallback;
 199 typedef Quarantine<QuarantineCallback, AsanChunk> AsanQuarantine;
 200 typedef AsanQuarantine::Cache QuarantineCache;
 201 static AsanQuarantine quarantine(LINKER_INITIALIZED);
 202 static QuarantineCache fallback_quarantine_cache(LINKER_INITIALIZED);
 203 static AllocatorCache fallback_allocator_cache;
 204 static SpinMutex fallback_mutex;
 205
 206 QuarantineCache *GetQuarantineCache(AsanThreadLocalMallocStorage *ms) {
 207   CHECK(ms);
 208   CHECK_LE(sizeof(QuarantineCache), sizeof(ms->quarantine_cache));
 209   return reinterpret_cast<QuarantineCache *>(ms->quarantine_cache);
 210 }
 211
 212 struct QuarantineCallback {
 213   explicit QuarantineCallback(AllocatorCache *cache)
 214       : cache_(cache) {
 215   }
 216
 217   void Recycle(AsanChunk *m) {
 218     CHECK_EQ(m->chunk_state, CHUNK_QUARANTINE);
 219     atomic_store((atomic_uint8_t*)m, CHUNK_AVAILABLE, memory_order_relaxed);
 220     CHECK_NE(m->alloc_tid, kInvalidTid);
 221     CHECK_NE(m->free_tid, kInvalidTid);
 222     PoisonShadow(m->Beg(),
 223                  RoundUpTo(m->UsedSize(), SHADOW_GRANULARITY),
 224                  kAsanHeapLeftRedzoneMagic);
 225     void *p = reinterpret_cast<void *>(m->AllocBeg());
 226     if (p != m) {
 227       uptr *alloc_magic = reinterpret_cast<uptr *>(p);
 228       CHECK_EQ(alloc_magic[0], kAllocBegMagic);
 229       // Clear the magic value, as allocator internals may overwrite the
 230       // contents of deallocated chunk, confusing GetAsanChunk lookup.
 231       alloc_magic[0] = 0;
 232       CHECK_EQ(alloc_magic[1], reinterpret_cast<uptr>(m));
 233     }
 234
 235     // Statistics.
 236     AsanStats &thread_stats = GetCurrentThreadStats();
 237     thread_stats.real_frees++;
 238     thread_stats.really_freed += m->UsedSize();
 239
 240     allocator.Deallocate(cache_, p);
 241   }
 242
 243   void *Allocate(uptr size) {
 244     return allocator.Allocate(cache_, size, 1, false);
 245   }
 246
 247   void Deallocate(void *p) {
 248     allocator.Deallocate(cache_, p);
 249   }
 250
 251   AllocatorCache *cache_;
 252 };
 253
 254 void InitializeAllocator() {
 255   allocator.Init();
 256   quarantine.Init((uptr)flags()->quarantine_size, kMaxThreadLocalQuarantine);
 257 }
 258
 259 void ReInitializeAllocator() {
 260   quarantine.Init((uptr)flags()->quarantine_size, kMaxThreadLocalQuarantine);
 261 }
 262
 263 static void *Allocate(uptr size, uptr alignment, BufferedStackTrace *stack,
 264                       AllocType alloc_type, bool can_fill) {
 265   if (UNLIKELY(!asan_inited))
 266     AsanInitFromRtl();
 267   Flags &fl = *flags();
 268   CHECK(stack);
 269   const uptr min_alignment = SHADOW_GRANULARITY;
 270   if (alignment < min_alignment)
 271     alignment = min_alignment;
 272   if (size == 0) {
 273     // We'd be happy to avoid allocating memory for zero-size requests, but
 274     // some programs/tests depend on this behavior and assume that malloc would
 275     // not return NULL even for zero-size allocations. Moreover, it looks like
 276     // operator new should never return NULL, and results of consecutive "new"
 277     // calls must be different even if the allocated size is zero.
 278     size = 1;
 279   }
 280   CHECK(IsPowerOfTwo(alignment));
 281   uptr rz_log = ComputeRZLog(size);
 282   uptr rz_size = RZLog2Size(rz_log);
 283   uptr rounded_size = RoundUpTo(Max(size, kChunkHeader2Size), alignment);
 284   uptr needed_size = rounded_size + rz_size;
 285   if (alignment > min_alignment)
 286     needed_size += alignment;
 287   bool using_primary_allocator = true;
 288   // If we are allocating from the secondary allocator, there will be no
 289   // automatic right redzone, so add the right redzone manually.
 290   if (!PrimaryAllocator::CanAllocate(needed_size, alignment)) {
 291     needed_size += rz_size;
 292     using_primary_allocator = false;
 293   }
 294   CHECK(IsAligned(needed_size, min_alignment));
 295   if (size > kMaxAllowedMallocSize || needed_size > kMaxAllowedMallocSize) {
 296     Report("WARNING: AddressSanitizer failed to allocate %p bytes\n",
 297            (void*)size);
 298     return AllocatorReturnNull();
 299   }
 300
 301   AsanThread *t = GetCurrentThread();
 302   void *allocated;
 303   if (t) {
 304     AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
 305     allocated = allocator.Allocate(cache, needed_size, 8, false);
 306   } else {
 307     SpinMutexLock l(&fallback_mutex);
 308     AllocatorCache *cache = &fallback_allocator_cache;
 309     allocated = allocator.Allocate(cache, needed_size, 8, false);
 310   }
 311
 312   if (*(u8 *)MEM_TO_SHADOW((uptr)allocated) == 0 && flags()->poison_heap) {
 313     // Heap poisoning is enabled, but the allocator provides an unpoisoned
 314     // chunk. This is possible if flags()->poison_heap was disabled for some
 315     // time, for example, due to flags()->start_disabled.
 316     // Anyway, poison the block before using it for anything else.
 317     uptr allocated_size = allocator.GetActuallyAllocatedSize(allocated);
 318     PoisonShadow((uptr)allocated, allocated_size, kAsanHeapLeftRedzoneMagic);
 319   }
 320
 321   uptr alloc_beg = reinterpret_cast<uptr>(allocated);
 322   uptr alloc_end = alloc_beg + needed_size;
 323   uptr beg_plus_redzone = alloc_beg + rz_size;
 324   uptr user_beg = beg_plus_redzone;
 325   if (!IsAligned(user_beg, alignment))
 326     user_beg = RoundUpTo(user_beg, alignment);
 327   uptr user_end = user_beg + size;
 328   CHECK_LE(user_end, alloc_end);
 329   uptr chunk_beg = user_beg - kChunkHeaderSize;
 330   AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
 331   m->alloc_type = alloc_type;
 332   m->rz_log = rz_log;
 333   u32 alloc_tid = t ? t->tid() : 0;
 334   m->alloc_tid = alloc_tid;
 335   CHECK_EQ(alloc_tid, m->alloc_tid);  // Does alloc_tid fit into the bitfield?
 336   m->free_tid = kInvalidTid;
 337   m->from_memalign = user_beg != beg_plus_redzone;
 338   if (alloc_beg != chunk_beg) {
 339     CHECK_LE(alloc_beg+ 2 * sizeof(uptr), chunk_beg);
 340     reinterpret_cast<uptr *>(alloc_beg)[0] = kAllocBegMagic;
 341     reinterpret_cast<uptr *>(alloc_beg)[1] = chunk_beg;
 342   }
 343   if (using_primary_allocator) {
 344     CHECK(size);
 345     m->user_requested_size = size;
 346     CHECK(allocator.FromPrimary(allocated));
 347   } else {
 348     CHECK(!allocator.FromPrimary(allocated));
 349     m->user_requested_size = SizeClassMap::kMaxSize;
 350     uptr *meta = reinterpret_cast<uptr *>(allocator.GetMetaData(allocated));
 351     meta[0] = size;
 352     meta[1] = chunk_beg;
 353   }
 354
 355   m->alloc_context_id = StackDepotPut(*stack);
 356
 357   uptr size_rounded_down_to_granularity = RoundDownTo(size, SHADOW_GRANULARITY);
 358   // Unpoison the bulk of the memory region.
 359   if (size_rounded_down_to_granularity)
 360     PoisonShadow(user_beg, size_rounded_down_to_granularity, 0);
 361   // Deal with the end of the region if size is not aligned to granularity.
 362   if (size != size_rounded_down_to_granularity && fl.poison_heap) {
 363     u8 *shadow = (u8*)MemToShadow(user_beg + size_rounded_down_to_granularity);
 364     *shadow = fl.poison_partial ? (size & (SHADOW_GRANULARITY - 1)) : 0;
 365   }
 366
 367   AsanStats &thread_stats = GetCurrentThreadStats();
 368   thread_stats.mallocs++;
 369   thread_stats.malloced += size;
 370   thread_stats.malloced_redzones += needed_size - size;
 371   uptr class_id = Min(kNumberOfSizeClasses, SizeClassMap::ClassID(needed_size));
 372   thread_stats.malloced_by_size[class_id]++;
 373   if (needed_size > SizeClassMap::kMaxSize)
 374     thread_stats.malloc_large++;
 375
 376   void *res = reinterpret_cast<void *>(user_beg);
 377   if (can_fill && fl.max_malloc_fill_size) {
 378     uptr fill_size = Min(size, (uptr)fl.max_malloc_fill_size);
 379     REAL(memset)(res, fl.malloc_fill_byte, fill_size);
 380   }
 381 #if CAN_SANITIZE_LEAKS
 382   m->lsan_tag = __lsan::DisabledInThisThread() ? __lsan::kIgnored
 383                                                : __lsan::kDirectlyLeaked;
 384 #endif
 385   // Must be the last mutation of metadata in this function.
 386   atomic_store((atomic_uint8_t *)m, CHUNK_ALLOCATED, memory_order_release);
 387   ASAN_MALLOC_HOOK(res, size);
 388   return res;
 389 }
 390
 391 static void ReportInvalidFree(void *ptr, u8 chunk_state,
 392                               BufferedStackTrace *stack) {
 393   if (chunk_state == CHUNK_QUARANTINE)
 394     ReportDoubleFree((uptr)ptr, stack);
 395   else
 396     ReportFreeNotMalloced((uptr)ptr, stack);
 397 }
 398
 399 static void AtomicallySetQuarantineFlag(AsanChunk *m, void *ptr,
 400                                         BufferedStackTrace *stack) {
 401   u8 old_chunk_state = CHUNK_ALLOCATED;
 402   // Flip the chunk_state atomically to avoid race on double-free.
 403   if (!atomic_compare_exchange_strong((atomic_uint8_t*)m, &old_chunk_state,
 404                                       CHUNK_QUARANTINE, memory_order_acquire))
 405     ReportInvalidFree(ptr, old_chunk_state, stack);
 406   CHECK_EQ(CHUNK_ALLOCATED, old_chunk_state);
 407 }
 408
 409 // Expects the chunk to already be marked as quarantined by using
 410 // AtomicallySetQuarantineFlag.
 411 static void QuarantineChunk(AsanChunk *m, void *ptr, BufferedStackTrace *stack,
 412                             AllocType alloc_type) {
 413   CHECK_EQ(m->chunk_state, CHUNK_QUARANTINE);
 414
 415   if (m->alloc_type != alloc_type && flags()->alloc_dealloc_mismatch)
 416     ReportAllocTypeMismatch((uptr)ptr, stack,
 417                             (AllocType)m->alloc_type, (AllocType)alloc_type);
 418
 419   CHECK_GE(m->alloc_tid, 0);
 420   if (SANITIZER_WORDSIZE == 64)  // On 32-bits this resides in user area.
 421     CHECK_EQ(m->free_tid, kInvalidTid);
 422   AsanThread *t = GetCurrentThread();
 423   m->free_tid = t ? t->tid() : 0;
 424   m->free_context_id = StackDepotPut(*stack);
 425   // Poison the region.
 426   PoisonShadow(m->Beg(),
 427                RoundUpTo(m->UsedSize(), SHADOW_GRANULARITY),
 428                kAsanHeapFreeMagic);
 429
 430   AsanStats &thread_stats = GetCurrentThreadStats();
 431   thread_stats.frees++;
 432   thread_stats.freed += m->UsedSize();
 433
 434   // Push into quarantine.
 435   if (t) {
 436     AsanThreadLocalMallocStorage *ms = &t->malloc_storage();
 437     AllocatorCache *ac = GetAllocatorCache(ms);
 438     quarantine.Put(GetQuarantineCache(ms), QuarantineCallback(ac),
 439                    m, m->UsedSize());
 440   } else {
 441     SpinMutexLock l(&fallback_mutex);
 442     AllocatorCache *ac = &fallback_allocator_cache;
 443     quarantine.Put(&fallback_quarantine_cache, QuarantineCallback(ac),
 444                    m, m->UsedSize());
 445   }
 446 }
 447
 448 static void Deallocate(void *ptr, uptr delete_size, BufferedStackTrace *stack,
 449                        AllocType alloc_type) {
 450   uptr p = reinterpret_cast<uptr>(ptr);
 451   if (p == 0) return;
 452
 453   uptr chunk_beg = p - kChunkHeaderSize;
 454   AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
 455   if (delete_size && flags()->new_delete_type_mismatch &&
 456       delete_size != m->UsedSize()) {
 457     ReportNewDeleteSizeMismatch(p, delete_size, stack);
 458   }
 459   ASAN_FREE_HOOK(ptr);
 460   // Must mark the chunk as quarantined before any changes to its metadata.
 461   AtomicallySetQuarantineFlag(m, ptr, stack);
 462   QuarantineChunk(m, ptr, stack, alloc_type);
 463 }
 464
 465 static void *Reallocate(void *old_ptr, uptr new_size,
 466                         BufferedStackTrace *stack) {
 467   CHECK(old_ptr && new_size);
 468   uptr p = reinterpret_cast<uptr>(old_ptr);
 469   uptr chunk_beg = p - kChunkHeaderSize;
 470   AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
 471
 472   AsanStats &thread_stats = GetCurrentThreadStats();
 473   thread_stats.reallocs++;
 474   thread_stats.realloced += new_size;
 475
 476   void *new_ptr = Allocate(new_size, 8, stack, FROM_MALLOC, true);
 477   if (new_ptr) {
 478     u8 chunk_state = m->chunk_state;
 479     if (chunk_state != CHUNK_ALLOCATED)
 480       ReportInvalidFree(old_ptr, chunk_state, stack);
 481     CHECK_NE(REAL(memcpy), (void*)0);
 482     uptr memcpy_size = Min(new_size, m->UsedSize());
 483     // If realloc() races with free(), we may start copying freed memory.
 484     // However, we will report racy double-free later anyway.
 485     REAL(memcpy)(new_ptr, old_ptr, memcpy_size);
 486     Deallocate(old_ptr, 0, stack, FROM_MALLOC);
 487   }
 488   return new_ptr;
 489 }
 490
 491 // Assumes alloc_beg == allocator.GetBlockBegin(alloc_beg).
 492 static AsanChunk *GetAsanChunk(void *alloc_beg) {
 493   if (!alloc_beg) return 0;
 494   if (!allocator.FromPrimary(alloc_beg)) {
 495     uptr *meta = reinterpret_cast<uptr *>(allocator.GetMetaData(alloc_beg));
 496     AsanChunk *m = reinterpret_cast<AsanChunk *>(meta[1]);
 497     return m;
 498   }
 499   uptr *alloc_magic = reinterpret_cast<uptr *>(alloc_beg);
 500   if (alloc_magic[0] == kAllocBegMagic)
 501     return reinterpret_cast<AsanChunk *>(alloc_magic[1]);
 502   return reinterpret_cast<AsanChunk *>(alloc_beg);
 503 }
 504
 505 static AsanChunk *GetAsanChunkByAddr(uptr p) {
 506   void *alloc_beg = allocator.GetBlockBegin(reinterpret_cast<void *>(p));
 507   return GetAsanChunk(alloc_beg);
 508 }
 509
 510 // Allocator must be locked when this function is called.
 511 static AsanChunk *GetAsanChunkByAddrFastLocked(uptr p) {
 512   void *alloc_beg =
 513       allocator.GetBlockBeginFastLocked(reinterpret_cast<void *>(p));
 514   return GetAsanChunk(alloc_beg);
 515 }
 516
 517 static uptr AllocationSize(uptr p) {
 518   AsanChunk *m = GetAsanChunkByAddr(p);
 519   if (!m) return 0;
 520   if (m->chunk_state != CHUNK_ALLOCATED) return 0;
 521   if (m->Beg() != p) return 0;
 522   return m->UsedSize();
 523 }
 524
 525 // We have an address between two chunks, and we want to report just one.
 526 AsanChunk *ChooseChunk(uptr addr,
 527                        AsanChunk *left_chunk, AsanChunk *right_chunk) {
 528   // Prefer an allocated chunk over freed chunk and freed chunk
 529   // over available chunk.
 530   if (left_chunk->chunk_state != right_chunk->chunk_state) {
 531     if (left_chunk->chunk_state == CHUNK_ALLOCATED)
 532       return left_chunk;
 533     if (right_chunk->chunk_state == CHUNK_ALLOCATED)
 534       return right_chunk;
 535     if (left_chunk->chunk_state == CHUNK_QUARANTINE)
 536       return left_chunk;
 537     if (right_chunk->chunk_state == CHUNK_QUARANTINE)
 538       return right_chunk;
 539   }
 540   // Same chunk_state: choose based on offset.
 541   sptr l_offset = 0, r_offset = 0;
 542   CHECK(AsanChunkView(left_chunk).AddrIsAtRight(addr, 1, &l_offset));
 543   CHECK(AsanChunkView(right_chunk).AddrIsAtLeft(addr, 1, &r_offset));
 544   if (l_offset < r_offset)
 545     return left_chunk;
 546   return right_chunk;
 547 }
 548
 549 AsanChunkView FindHeapChunkByAddress(uptr addr) {
 550   AsanChunk *m1 = GetAsanChunkByAddr(addr);
 551   if (!m1) return AsanChunkView(m1);
 552   sptr offset = 0;
 553   if (AsanChunkView(m1).AddrIsAtLeft(addr, 1, &offset)) {
 554     // The address is in the chunk's left redzone, so maybe it is actually
 555     // a right buffer overflow from the other chunk to the left.
 556     // Search a bit to the left to see if there is another chunk.
 557     AsanChunk *m2 = 0;
 558     for (uptr l = 1; l < GetPageSizeCached(); l++) {
 559       m2 = GetAsanChunkByAddr(addr - l);
 560       if (m2 == m1) continue;  // Still the same chunk.
 561       break;
 562     }
 563     if (m2 && AsanChunkView(m2).AddrIsAtRight(addr, 1, &offset))
 564       m1 = ChooseChunk(addr, m2, m1);
 565   }
 566   return AsanChunkView(m1);
 567 }
 568
 569 void AsanThreadLocalMallocStorage::CommitBack() {
 570   AllocatorCache *ac = GetAllocatorCache(this);
 571   quarantine.Drain(GetQuarantineCache(this), QuarantineCallback(ac));
 572   allocator.SwallowCache(GetAllocatorCache(this));
 573 }
 574
 575 void PrintInternalAllocatorStats() {
 576   allocator.PrintStats();
 577 }
 578
 579 void *asan_memalign(uptr alignment, uptr size, BufferedStackTrace *stack,
 580                     AllocType alloc_type) {
 581   return Allocate(size, alignment, stack, alloc_type, true);
 582 }
 583
 584 void asan_free(void *ptr, BufferedStackTrace *stack, AllocType alloc_type) {
 585   Deallocate(ptr, 0, stack, alloc_type);
 586 }
 587
 588 void asan_sized_free(void *ptr, uptr size, BufferedStackTrace *stack,
 589                      AllocType alloc_type) {
 590   Deallocate(ptr, size, stack, alloc_type);
 591 }
 592
 593 void *asan_malloc(uptr size, BufferedStackTrace *stack) {
 594   return Allocate(size, 8, stack, FROM_MALLOC, true);
 595 }
 596
 597 void *asan_calloc(uptr nmemb, uptr size, BufferedStackTrace *stack) {
 598   if (CallocShouldReturnNullDueToOverflow(size, nmemb))
 599     return AllocatorReturnNull();
 600   void *ptr = Allocate(nmemb * size, 8, stack, FROM_MALLOC, false);
 601   // If the memory comes from the secondary allocator no need to clear it
 602   // as it comes directly from mmap.
 603   if (ptr && allocator.FromPrimary(ptr))
 604     REAL(memset)(ptr, 0, nmemb * size);
 605   return ptr;
 606 }
 607
 608 void *asan_realloc(void *p, uptr size, BufferedStackTrace *stack) {
 609   if (p == 0)
 610     return Allocate(size, 8, stack, FROM_MALLOC, true);
 611   if (size == 0) {
 612     Deallocate(p, 0, stack, FROM_MALLOC);
 613     return 0;
 614   }
 615   return Reallocate(p, size, stack);
 616 }
 617
 618 void *asan_valloc(uptr size, BufferedStackTrace *stack) {
 619   return Allocate(size, GetPageSizeCached(), stack, FROM_MALLOC, true);
 620 }
 621
 622 void *asan_pvalloc(uptr size, BufferedStackTrace *stack) {
 623   uptr PageSize = GetPageSizeCached();
 624   size = RoundUpTo(size, PageSize);
 625   if (size == 0) {
 626     // pvalloc(0) should allocate one page.
 627     size = PageSize;
 628   }
 629   return Allocate(size, PageSize, stack, FROM_MALLOC, true);
 630 }
 631
 632 int asan_posix_memalign(void **memptr, uptr alignment, uptr size,
 633                         BufferedStackTrace *stack) {
 634   void *ptr = Allocate(size, alignment, stack, FROM_MALLOC, true);
 635   CHECK(IsAligned((uptr)ptr, alignment));
 636   *memptr = ptr;
 637   return 0;
 638 }
 639
 640 uptr asan_malloc_usable_size(void *ptr, uptr pc, uptr bp) {
 641   if (ptr == 0) return 0;
 642   uptr usable_size = AllocationSize(reinterpret_cast<uptr>(ptr));
 643   if (flags()->check_malloc_usable_size && (usable_size == 0)) {
 644     GET_STACK_TRACE_FATAL(pc, bp);
 645     ReportMallocUsableSizeNotOwned((uptr)ptr, &stack);
 646   }
 647   return usable_size;
 648 }
 649
 650 uptr asan_mz_size(const void *ptr) {
 651   return AllocationSize(reinterpret_cast<uptr>(ptr));
 652 }
 653
 654 void asan_mz_force_lock() {
 655   allocator.ForceLock();
 656   fallback_mutex.Lock();
 657 }
 658
 659 void asan_mz_force_unlock() {
 660   fallback_mutex.Unlock();
 661   allocator.ForceUnlock();
 662 }
 663
 664 }  // namespace __asan
 665
 666 // --- Implementation of LSan-specific functions --- {{{1
 667 namespace __lsan {
 668 void LockAllocator() {
 669   __asan::allocator.ForceLock();
 670 }
 671
 672 void UnlockAllocator() {
 673   __asan::allocator.ForceUnlock();
 674 }
 675
 676 void GetAllocatorGlobalRange(uptr *begin, uptr *end) {
 677   *begin = (uptr)&__asan::allocator;
 678   *end = *begin + sizeof(__asan::allocator);
 679 }
 680
 681 uptr PointsIntoChunk(void* p) {
 682   uptr addr = reinterpret_cast<uptr>(p);
 683   __asan::AsanChunk *m = __asan::GetAsanChunkByAddrFastLocked(addr);
 684   if (!m) return 0;
 685   uptr chunk = m->Beg();
 686   if (m->chunk_state != __asan::CHUNK_ALLOCATED)
 687     return 0;
 688   if (m->AddrIsInside(addr, /*locked_version=*/true))
 689     return chunk;
 690   if (IsSpecialCaseOfOperatorNew0(chunk, m->UsedSize(/*locked_version*/ true),
 691                                   addr))
 692     return chunk;
 693   return 0;
 694 }
 695
 696 uptr GetUserBegin(uptr chunk) {
 697   __asan::AsanChunk *m =
 698       __asan::GetAsanChunkByAddrFastLocked(chunk);
 699   CHECK(m);
 700   return m->Beg();
 701 }
 702
 703 LsanMetadata::LsanMetadata(uptr chunk) {
 704   metadata_ = reinterpret_cast<void *>(chunk - __asan::kChunkHeaderSize);
 705 }
 706
 707 bool LsanMetadata::allocated() const {
 708   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
 709   return m->chunk_state == __asan::CHUNK_ALLOCATED;
 710 }
 711
 712 ChunkTag LsanMetadata::tag() const {
 713   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
 714   return static_cast<ChunkTag>(m->lsan_tag);
 715 }
 716
 717 void LsanMetadata::set_tag(ChunkTag value) {
 718   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
 719   m->lsan_tag = value;
 720 }
 721
 722 uptr LsanMetadata::requested_size() const {
 723   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
 724   return m->UsedSize(/*locked_version=*/true);
 725 }
 726
 727 u32 LsanMetadata::stack_trace_id() const {
 728   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
 729   return m->alloc_context_id;
 730 }
 731
 732 void ForEachChunk(ForEachChunkCallback callback, void *arg) {
 733   __asan::allocator.ForEachChunk(callback, arg);
 734 }
 735
 736 IgnoreObjectResult IgnoreObjectLocked(const void *p) {
 737   uptr addr = reinterpret_cast<uptr>(p);
 738   __asan::AsanChunk *m = __asan::GetAsanChunkByAddr(addr);
 739   if (!m) return kIgnoreObjectInvalid;
 740   if ((m->chunk_state == __asan::CHUNK_ALLOCATED) && m->AddrIsInside(addr)) {
 741     if (m->lsan_tag == kIgnored)
 742       return kIgnoreObjectAlreadyIgnored;
 743     m->lsan_tag = __lsan::kIgnored;
 744     return kIgnoreObjectSuccess;
 745   } else {
 746     return kIgnoreObjectInvalid;
 747   }
 748 }
 749 }  // namespace __lsan
 750
 751 // ---------------------- Interface ---------------- {{{1
 752 using namespace __asan;  // NOLINT
 753
 754 // ASan allocator doesn't reserve extra bytes, so normally we would
 755 // just return "size". We don't want to expose our redzone sizes, etc here.
 756 uptr __sanitizer_get_estimated_allocated_size(uptr size) {
 757   return size;
 758 }
 759
 760 int __sanitizer_get_ownership(const void *p) {
 761   uptr ptr = reinterpret_cast<uptr>(p);
 762   return (AllocationSize(ptr) > 0);
 763 }
 764
 765 uptr __sanitizer_get_allocated_size(const void *p) {
 766   if (p == 0) return 0;
 767   uptr ptr = reinterpret_cast<uptr>(p);
 768   uptr allocated_size = AllocationSize(ptr);
 769   // Die if p is not malloced or if it is already freed.
 770   if (allocated_size == 0) {
 771     GET_STACK_TRACE_FATAL_HERE;
 772     ReportSanitizerGetAllocatedSizeNotOwned(ptr, &stack);
 773   }
 774   return allocated_size;
 775 }
 776
 777 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
 778 // Provide default (no-op) implementation of malloc hooks.
 779 extern "C" {
 780 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 781 void __sanitizer_malloc_hook(void *ptr, uptr size) {
 782   (void)ptr;
 783   (void)size;
 784 }
 785 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
 786 void __sanitizer_free_hook(void *ptr) {
 787   (void)ptr;
 788 }
 789 }  // extern "C"
 790 #endif