1 //===-- asan_allocator.cc -------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file is a part of AddressSanitizer, an address sanity checker.
11 //
12 // Implementation of ASan's memory allocator, 2-nd version.
13 // This variant uses the allocator from sanitizer_common, i.e. the one shared
14 // with ThreadSanitizer and MemorySanitizer.
15 //
16 //===----------------------------------------------------------------------===//
17 
18 #include "asan_allocator.h"
19 #include "asan_mapping.h"
20 #include "asan_poisoning.h"
21 #include "asan_report.h"
22 #include "asan_stack.h"
23 #include "asan_thread.h"
24 #include "sanitizer_common/sanitizer_allocator_interface.h"
25 #include "sanitizer_common/sanitizer_flags.h"
26 #include "sanitizer_common/sanitizer_internal_defs.h"
27 #include "sanitizer_common/sanitizer_list.h"
28 #include "sanitizer_common/sanitizer_stackdepot.h"
29 #include "sanitizer_common/sanitizer_quarantine.h"
30 #include "lsan/lsan_common.h"
31 
32 namespace __asan {
33 
34 // Valid redzone sizes are 16, 32, 64, ... 2048, so we encode them in 3 bits.
35 // We use adaptive redzones: for larger allocation larger redzones are used.
RZLog2Size(u32 rz_log)36 static u32 RZLog2Size(u32 rz_log) {
37   CHECK_LT(rz_log, 8);
38   return 16 << rz_log;
39 }
40 
RZSize2Log(u32 rz_size)41 static u32 RZSize2Log(u32 rz_size) {
42   CHECK_GE(rz_size, 16);
43   CHECK_LE(rz_size, 2048);
44   CHECK(IsPowerOfTwo(rz_size));
45   u32 res = Log2(rz_size) - 4;
46   CHECK_EQ(rz_size, RZLog2Size(res));
47   return res;
48 }
49 
50 static AsanAllocator &get_allocator();
51 
52 // The memory chunk allocated from the underlying allocator looks like this:
53 // L L L L L L H H U U U U U U R R
54 //   L -- left redzone words (0 or more bytes)
55 //   H -- ChunkHeader (16 bytes), which is also a part of the left redzone.
56 //   U -- user memory.
57 //   R -- right redzone (0 or more bytes)
58 // ChunkBase consists of ChunkHeader and other bytes that overlap with user
59 // memory.
60 
61 // If the left redzone is greater than the ChunkHeader size we store a magic
62 // value in the first uptr word of the memory block and store the address of
63 // ChunkBase in the next uptr.
64 // M B L L L L L L L L L  H H U U U U U U
65 //   |                    ^
66 //   ---------------------|
67 //   M -- magic value kAllocBegMagic
68 //   B -- address of ChunkHeader pointing to the first 'H'
69 static const uptr kAllocBegMagic = 0xCC6E96B9;
70 
71 struct ChunkHeader {
72   // 1-st 8 bytes.
73   u32 chunk_state       : 8;  // Must be first.
74   u32 alloc_tid         : 24;
75 
76   u32 free_tid          : 24;
77   u32 from_memalign     : 1;
78   u32 alloc_type        : 2;
79   u32 rz_log            : 3;
80   u32 lsan_tag          : 2;
81   // 2-nd 8 bytes
82   // This field is used for small sizes. For large sizes it is equal to
83   // SizeClassMap::kMaxSize and the actual size is stored in the
84   // SecondaryAllocator's metadata.
85   u32 user_requested_size;
86   u32 alloc_context_id;
87 };
88 
89 struct ChunkBase : ChunkHeader {
90   // Header2, intersects with user memory.
91   u32 free_context_id;
92 };
93 
94 static const uptr kChunkHeaderSize = sizeof(ChunkHeader);
95 static const uptr kChunkHeader2Size = sizeof(ChunkBase) - kChunkHeaderSize;
96 COMPILER_CHECK(kChunkHeaderSize == 16);
97 COMPILER_CHECK(kChunkHeader2Size <= 16);
98 
99 // Every chunk of memory allocated by this allocator can be in one of 3 states:
100 // CHUNK_AVAILABLE: the chunk is in the free list and ready to be allocated.
101 // CHUNK_ALLOCATED: the chunk is allocated and not yet freed.
102 // CHUNK_QUARANTINE: the chunk was freed and put into quarantine zone.
103 enum {
104   CHUNK_AVAILABLE  = 0,  // 0 is the default value even if we didn't set it.
105   CHUNK_ALLOCATED  = 2,
106   CHUNK_QUARANTINE = 3
107 };
108 
109 struct AsanChunk: ChunkBase {
Beg__asan::AsanChunk110   uptr Beg() { return reinterpret_cast<uptr>(this) + kChunkHeaderSize; }
UsedSize__asan::AsanChunk111   uptr UsedSize(bool locked_version = false) {
112     if (user_requested_size != SizeClassMap::kMaxSize)
113       return user_requested_size;
114     return *reinterpret_cast<uptr *>(
115                get_allocator().GetMetaData(AllocBeg(locked_version)));
116   }
AllocBeg__asan::AsanChunk117   void *AllocBeg(bool locked_version = false) {
118     if (from_memalign) {
119       if (locked_version)
120         return get_allocator().GetBlockBeginFastLocked(
121             reinterpret_cast<void *>(this));
122       return get_allocator().GetBlockBegin(reinterpret_cast<void *>(this));
123     }
124     return reinterpret_cast<void*>(Beg() - RZLog2Size(rz_log));
125   }
AddrIsInside__asan::AsanChunk126   bool AddrIsInside(uptr addr, bool locked_version = false) {
127     return (addr >= Beg()) && (addr < Beg() + UsedSize(locked_version));
128   }
129 };
130 
131 struct QuarantineCallback {
QuarantineCallback__asan::QuarantineCallback132   explicit QuarantineCallback(AllocatorCache *cache)
133       : cache_(cache) {
134   }
135 
Recycle__asan::QuarantineCallback136   void Recycle(AsanChunk *m) {
137     CHECK_EQ(m->chunk_state, CHUNK_QUARANTINE);
138     atomic_store((atomic_uint8_t*)m, CHUNK_AVAILABLE, memory_order_relaxed);
139     CHECK_NE(m->alloc_tid, kInvalidTid);
140     CHECK_NE(m->free_tid, kInvalidTid);
141     PoisonShadow(m->Beg(),
142                  RoundUpTo(m->UsedSize(), SHADOW_GRANULARITY),
143                  kAsanHeapLeftRedzoneMagic);
144     void *p = reinterpret_cast<void *>(m->AllocBeg());
145     if (p != m) {
146       uptr *alloc_magic = reinterpret_cast<uptr *>(p);
147       CHECK_EQ(alloc_magic[0], kAllocBegMagic);
148       // Clear the magic value, as allocator internals may overwrite the
149       // contents of deallocated chunk, confusing GetAsanChunk lookup.
150       alloc_magic[0] = 0;
151       CHECK_EQ(alloc_magic[1], reinterpret_cast<uptr>(m));
152     }
153 
154     // Statistics.
155     AsanStats &thread_stats = GetCurrentThreadStats();
156     thread_stats.real_frees++;
157     thread_stats.really_freed += m->UsedSize();
158 
159     get_allocator().Deallocate(cache_, p);
160   }
161 
Allocate__asan::QuarantineCallback162   void *Allocate(uptr size) {
163     return get_allocator().Allocate(cache_, size, 1, false);
164   }
165 
Deallocate__asan::QuarantineCallback166   void Deallocate(void *p) {
167     get_allocator().Deallocate(cache_, p);
168   }
169 
170   AllocatorCache *cache_;
171 };
172 
173 typedef Quarantine<QuarantineCallback, AsanChunk> AsanQuarantine;
174 typedef AsanQuarantine::Cache QuarantineCache;
175 
OnMap(uptr p,uptr size) const176 void AsanMapUnmapCallback::OnMap(uptr p, uptr size) const {
177   PoisonShadow(p, size, kAsanHeapLeftRedzoneMagic);
178   // Statistics.
179   AsanStats &thread_stats = GetCurrentThreadStats();
180   thread_stats.mmaps++;
181   thread_stats.mmaped += size;
182 }
OnUnmap(uptr p,uptr size) const183 void AsanMapUnmapCallback::OnUnmap(uptr p, uptr size) const {
184   PoisonShadow(p, size, 0);
185   // We are about to unmap a chunk of user memory.
186   // Mark the corresponding shadow memory as not needed.
187   FlushUnneededASanShadowMemory(p, size);
188   // Statistics.
189   AsanStats &thread_stats = GetCurrentThreadStats();
190   thread_stats.munmaps++;
191   thread_stats.munmaped += size;
192 }
193 
194 // We can not use THREADLOCAL because it is not supported on some of the
195 // platforms we care about (OSX 10.6, Android).
196 // static THREADLOCAL AllocatorCache cache;
GetAllocatorCache(AsanThreadLocalMallocStorage * ms)197 AllocatorCache *GetAllocatorCache(AsanThreadLocalMallocStorage *ms) {
198   CHECK(ms);
199   return &ms->allocator_cache;
200 }
201 
GetQuarantineCache(AsanThreadLocalMallocStorage * ms)202 QuarantineCache *GetQuarantineCache(AsanThreadLocalMallocStorage *ms) {
203   CHECK(ms);
204   CHECK_LE(sizeof(QuarantineCache), sizeof(ms->quarantine_cache));
205   return reinterpret_cast<QuarantineCache *>(ms->quarantine_cache);
206 }
207 
SetFrom(const Flags * f,const CommonFlags * cf)208 void AllocatorOptions::SetFrom(const Flags *f, const CommonFlags *cf) {
209   quarantine_size_mb = f->quarantine_size_mb;
210   min_redzone = f->redzone;
211   max_redzone = f->max_redzone;
212   may_return_null = cf->allocator_may_return_null;
213   alloc_dealloc_mismatch = f->alloc_dealloc_mismatch;
214 }
215 
CopyTo(Flags * f,CommonFlags * cf)216 void AllocatorOptions::CopyTo(Flags *f, CommonFlags *cf) {
217   f->quarantine_size_mb = quarantine_size_mb;
218   f->redzone = min_redzone;
219   f->max_redzone = max_redzone;
220   cf->allocator_may_return_null = may_return_null;
221   f->alloc_dealloc_mismatch = alloc_dealloc_mismatch;
222 }
223 
224 struct Allocator {
225   static const uptr kMaxAllowedMallocSize =
226       FIRST_32_SECOND_64(3UL << 30, 1ULL << 40);
227   static const uptr kMaxThreadLocalQuarantine =
228       FIRST_32_SECOND_64(1 << 18, 1 << 20);
229 
230   AsanAllocator allocator;
231   AsanQuarantine quarantine;
232   StaticSpinMutex fallback_mutex;
233   AllocatorCache fallback_allocator_cache;
234   QuarantineCache fallback_quarantine_cache;
235 
236   // ------------------- Options --------------------------
237   atomic_uint16_t min_redzone;
238   atomic_uint16_t max_redzone;
239   atomic_uint8_t alloc_dealloc_mismatch;
240 
241   // ------------------- Initialization ------------------------
Allocator__asan::Allocator242   explicit Allocator(LinkerInitialized)
243       : quarantine(LINKER_INITIALIZED),
244         fallback_quarantine_cache(LINKER_INITIALIZED) {}
245 
CheckOptions__asan::Allocator246   void CheckOptions(const AllocatorOptions &options) const {
247     CHECK_GE(options.min_redzone, 16);
248     CHECK_GE(options.max_redzone, options.min_redzone);
249     CHECK_LE(options.max_redzone, 2048);
250     CHECK(IsPowerOfTwo(options.min_redzone));
251     CHECK(IsPowerOfTwo(options.max_redzone));
252   }
253 
SharedInitCode__asan::Allocator254   void SharedInitCode(const AllocatorOptions &options) {
255     CheckOptions(options);
256     quarantine.Init((uptr)options.quarantine_size_mb << 20,
257                     kMaxThreadLocalQuarantine);
258     atomic_store(&alloc_dealloc_mismatch, options.alloc_dealloc_mismatch,
259                  memory_order_release);
260     atomic_store(&min_redzone, options.min_redzone, memory_order_release);
261     atomic_store(&max_redzone, options.max_redzone, memory_order_release);
262   }
263 
Initialize__asan::Allocator264   void Initialize(const AllocatorOptions &options) {
265     allocator.Init(options.may_return_null);
266     SharedInitCode(options);
267   }
268 
ReInitialize__asan::Allocator269   void ReInitialize(const AllocatorOptions &options) {
270     allocator.SetMayReturnNull(options.may_return_null);
271     SharedInitCode(options);
272   }
273 
GetOptions__asan::Allocator274   void GetOptions(AllocatorOptions *options) const {
275     options->quarantine_size_mb = quarantine.GetSize() >> 20;
276     options->min_redzone = atomic_load(&min_redzone, memory_order_acquire);
277     options->max_redzone = atomic_load(&max_redzone, memory_order_acquire);
278     options->may_return_null = allocator.MayReturnNull();
279     options->alloc_dealloc_mismatch =
280         atomic_load(&alloc_dealloc_mismatch, memory_order_acquire);
281   }
282 
283   // -------------------- Helper methods. -------------------------
ComputeRZLog__asan::Allocator284   uptr ComputeRZLog(uptr user_requested_size) {
285     u32 rz_log =
286       user_requested_size <= 64        - 16   ? 0 :
287       user_requested_size <= 128       - 32   ? 1 :
288       user_requested_size <= 512       - 64   ? 2 :
289       user_requested_size <= 4096      - 128  ? 3 :
290       user_requested_size <= (1 << 14) - 256  ? 4 :
291       user_requested_size <= (1 << 15) - 512  ? 5 :
292       user_requested_size <= (1 << 16) - 1024 ? 6 : 7;
293     u32 min_rz = atomic_load(&min_redzone, memory_order_acquire);
294     u32 max_rz = atomic_load(&max_redzone, memory_order_acquire);
295     return Min(Max(rz_log, RZSize2Log(min_rz)), RZSize2Log(max_rz));
296   }
297 
298   // We have an address between two chunks, and we want to report just one.
ChooseChunk__asan::Allocator299   AsanChunk *ChooseChunk(uptr addr, AsanChunk *left_chunk,
300                          AsanChunk *right_chunk) {
301     // Prefer an allocated chunk over freed chunk and freed chunk
302     // over available chunk.
303     if (left_chunk->chunk_state != right_chunk->chunk_state) {
304       if (left_chunk->chunk_state == CHUNK_ALLOCATED)
305         return left_chunk;
306       if (right_chunk->chunk_state == CHUNK_ALLOCATED)
307         return right_chunk;
308       if (left_chunk->chunk_state == CHUNK_QUARANTINE)
309         return left_chunk;
310       if (right_chunk->chunk_state == CHUNK_QUARANTINE)
311         return right_chunk;
312     }
313     // Same chunk_state: choose based on offset.
314     sptr l_offset = 0, r_offset = 0;
315     CHECK(AsanChunkView(left_chunk).AddrIsAtRight(addr, 1, &l_offset));
316     CHECK(AsanChunkView(right_chunk).AddrIsAtLeft(addr, 1, &r_offset));
317     if (l_offset < r_offset)
318       return left_chunk;
319     return right_chunk;
320   }
321 
322   // -------------------- Allocation/Deallocation routines ---------------
Allocate__asan::Allocator323   void *Allocate(uptr size, uptr alignment, BufferedStackTrace *stack,
324                  AllocType alloc_type, bool can_fill) {
325     if (UNLIKELY(!asan_inited))
326       AsanInitFromRtl();
327     Flags &fl = *flags();
328     CHECK(stack);
329     const uptr min_alignment = SHADOW_GRANULARITY;
330     if (alignment < min_alignment)
331       alignment = min_alignment;
332     if (size == 0) {
333       // We'd be happy to avoid allocating memory for zero-size requests, but
334       // some programs/tests depend on this behavior and assume that malloc
335       // would not return NULL even for zero-size allocations. Moreover, it
336       // looks like operator new should never return NULL, and results of
337       // consecutive "new" calls must be different even if the allocated size
338       // is zero.
339       size = 1;
340     }
341     CHECK(IsPowerOfTwo(alignment));
342     uptr rz_log = ComputeRZLog(size);
343     uptr rz_size = RZLog2Size(rz_log);
344     uptr rounded_size = RoundUpTo(Max(size, kChunkHeader2Size), alignment);
345     uptr needed_size = rounded_size + rz_size;
346     if (alignment > min_alignment)
347       needed_size += alignment;
348     bool using_primary_allocator = true;
349     // If we are allocating from the secondary allocator, there will be no
350     // automatic right redzone, so add the right redzone manually.
351     if (!PrimaryAllocator::CanAllocate(needed_size, alignment)) {
352       needed_size += rz_size;
353       using_primary_allocator = false;
354     }
355     CHECK(IsAligned(needed_size, min_alignment));
356     if (size > kMaxAllowedMallocSize || needed_size > kMaxAllowedMallocSize) {
357       Report("WARNING: AddressSanitizer failed to allocate 0x%zx bytes\n",
358              (void*)size);
359       return allocator.ReturnNullOrDie();
360     }
361 
362     AsanThread *t = GetCurrentThread();
363     void *allocated;
364     bool check_rss_limit = true;
365     if (t) {
366       AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
367       allocated =
368           allocator.Allocate(cache, needed_size, 8, false, check_rss_limit);
369     } else {
370       SpinMutexLock l(&fallback_mutex);
371       AllocatorCache *cache = &fallback_allocator_cache;
372       allocated =
373           allocator.Allocate(cache, needed_size, 8, false, check_rss_limit);
374     }
375 
376     if (!allocated)
377       return allocator.ReturnNullOrDie();
378 
379     if (*(u8 *)MEM_TO_SHADOW((uptr)allocated) == 0 && CanPoisonMemory()) {
380       // Heap poisoning is enabled, but the allocator provides an unpoisoned
381       // chunk. This is possible if CanPoisonMemory() was false for some
382       // time, for example, due to flags()->start_disabled.
383       // Anyway, poison the block before using it for anything else.
384       uptr allocated_size = allocator.GetActuallyAllocatedSize(allocated);
385       PoisonShadow((uptr)allocated, allocated_size, kAsanHeapLeftRedzoneMagic);
386     }
387 
388     uptr alloc_beg = reinterpret_cast<uptr>(allocated);
389     uptr alloc_end = alloc_beg + needed_size;
390     uptr beg_plus_redzone = alloc_beg + rz_size;
391     uptr user_beg = beg_plus_redzone;
392     if (!IsAligned(user_beg, alignment))
393       user_beg = RoundUpTo(user_beg, alignment);
394     uptr user_end = user_beg + size;
395     CHECK_LE(user_end, alloc_end);
396     uptr chunk_beg = user_beg - kChunkHeaderSize;
397     AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
398     m->alloc_type = alloc_type;
399     m->rz_log = rz_log;
400     u32 alloc_tid = t ? t->tid() : 0;
401     m->alloc_tid = alloc_tid;
402     CHECK_EQ(alloc_tid, m->alloc_tid);  // Does alloc_tid fit into the bitfield?
403     m->free_tid = kInvalidTid;
404     m->from_memalign = user_beg != beg_plus_redzone;
405     if (alloc_beg != chunk_beg) {
406       CHECK_LE(alloc_beg+ 2 * sizeof(uptr), chunk_beg);
407       reinterpret_cast<uptr *>(alloc_beg)[0] = kAllocBegMagic;
408       reinterpret_cast<uptr *>(alloc_beg)[1] = chunk_beg;
409     }
410     if (using_primary_allocator) {
411       CHECK(size);
412       m->user_requested_size = size;
413       CHECK(allocator.FromPrimary(allocated));
414     } else {
415       CHECK(!allocator.FromPrimary(allocated));
416       m->user_requested_size = SizeClassMap::kMaxSize;
417       uptr *meta = reinterpret_cast<uptr *>(allocator.GetMetaData(allocated));
418       meta[0] = size;
419       meta[1] = chunk_beg;
420     }
421 
422     m->alloc_context_id = StackDepotPut(*stack);
423 
424     uptr size_rounded_down_to_granularity =
425         RoundDownTo(size, SHADOW_GRANULARITY);
426     // Unpoison the bulk of the memory region.
427     if (size_rounded_down_to_granularity)
428       PoisonShadow(user_beg, size_rounded_down_to_granularity, 0);
429     // Deal with the end of the region if size is not aligned to granularity.
430     if (size != size_rounded_down_to_granularity && CanPoisonMemory()) {
431       u8 *shadow =
432           (u8 *)MemToShadow(user_beg + size_rounded_down_to_granularity);
433       *shadow = fl.poison_partial ? (size & (SHADOW_GRANULARITY - 1)) : 0;
434     }
435 
436     AsanStats &thread_stats = GetCurrentThreadStats();
437     thread_stats.mallocs++;
438     thread_stats.malloced += size;
439     thread_stats.malloced_redzones += needed_size - size;
440     if (needed_size > SizeClassMap::kMaxSize)
441       thread_stats.malloc_large++;
442     else
443       thread_stats.malloced_by_size[SizeClassMap::ClassID(needed_size)]++;
444 
445     void *res = reinterpret_cast<void *>(user_beg);
446     if (can_fill && fl.max_malloc_fill_size) {
447       uptr fill_size = Min(size, (uptr)fl.max_malloc_fill_size);
448       REAL(memset)(res, fl.malloc_fill_byte, fill_size);
449     }
450 #if CAN_SANITIZE_LEAKS
451     m->lsan_tag = __lsan::DisabledInThisThread() ? __lsan::kIgnored
452                                                  : __lsan::kDirectlyLeaked;
453 #endif
454     // Must be the last mutation of metadata in this function.
455     atomic_store((atomic_uint8_t *)m, CHUNK_ALLOCATED, memory_order_release);
456     ASAN_MALLOC_HOOK(res, size);
457     return res;
458   }
459 
460   // Set quarantine flag if chunk is allocated, issue ASan error report on
461   // available and quarantined chunks. Return true on success, false otherwise.
AtomicallySetQuarantineFlagIfAllocated__asan::Allocator462   bool AtomicallySetQuarantineFlagIfAllocated(AsanChunk *m, void *ptr,
463                                    BufferedStackTrace *stack) {
464     u8 old_chunk_state = CHUNK_ALLOCATED;
465     // Flip the chunk_state atomically to avoid race on double-free.
466     if (!atomic_compare_exchange_strong((atomic_uint8_t *)m, &old_chunk_state,
467                                         CHUNK_QUARANTINE,
468                                         memory_order_acquire)) {
469       ReportInvalidFree(ptr, old_chunk_state, stack);
470       // It's not safe to push a chunk in quarantine on invalid free.
471       return false;
472     }
473     CHECK_EQ(CHUNK_ALLOCATED, old_chunk_state);
474     return true;
475   }
476 
477   // Expects the chunk to already be marked as quarantined by using
478   // AtomicallySetQuarantineFlagIfAllocated.
QuarantineChunk__asan::Allocator479   void QuarantineChunk(AsanChunk *m, void *ptr, BufferedStackTrace *stack,
480                        AllocType alloc_type) {
481     CHECK_EQ(m->chunk_state, CHUNK_QUARANTINE);
482     CHECK_GE(m->alloc_tid, 0);
483     if (SANITIZER_WORDSIZE == 64)  // On 32-bits this resides in user area.
484       CHECK_EQ(m->free_tid, kInvalidTid);
485     AsanThread *t = GetCurrentThread();
486     m->free_tid = t ? t->tid() : 0;
487     m->free_context_id = StackDepotPut(*stack);
488     // Poison the region.
489     PoisonShadow(m->Beg(),
490                  RoundUpTo(m->UsedSize(), SHADOW_GRANULARITY),
491                  kAsanHeapFreeMagic);
492 
493     AsanStats &thread_stats = GetCurrentThreadStats();
494     thread_stats.frees++;
495     thread_stats.freed += m->UsedSize();
496 
497     // Push into quarantine.
498     if (t) {
499       AsanThreadLocalMallocStorage *ms = &t->malloc_storage();
500       AllocatorCache *ac = GetAllocatorCache(ms);
501       quarantine.Put(GetQuarantineCache(ms), QuarantineCallback(ac), m,
502                            m->UsedSize());
503     } else {
504       SpinMutexLock l(&fallback_mutex);
505       AllocatorCache *ac = &fallback_allocator_cache;
506       quarantine.Put(&fallback_quarantine_cache, QuarantineCallback(ac), m,
507                            m->UsedSize());
508     }
509   }
510 
Deallocate__asan::Allocator511   void Deallocate(void *ptr, uptr delete_size, BufferedStackTrace *stack,
512                   AllocType alloc_type) {
513     uptr p = reinterpret_cast<uptr>(ptr);
514     if (p == 0) return;
515 
516     uptr chunk_beg = p - kChunkHeaderSize;
517     AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
518 
519     ASAN_FREE_HOOK(ptr);
520     // Must mark the chunk as quarantined before any changes to its metadata.
521     // Do not quarantine given chunk if we failed to set CHUNK_QUARANTINE flag.
522     if (!AtomicallySetQuarantineFlagIfAllocated(m, ptr, stack)) return;
523 
524     if (m->alloc_type != alloc_type) {
525       if (atomic_load(&alloc_dealloc_mismatch, memory_order_acquire)) {
526         ReportAllocTypeMismatch((uptr)ptr, stack, (AllocType)m->alloc_type,
527                                 (AllocType)alloc_type);
528       }
529     }
530 
531     if (delete_size && flags()->new_delete_type_mismatch &&
532         delete_size != m->UsedSize()) {
533       ReportNewDeleteSizeMismatch(p, m->UsedSize(), delete_size, stack);
534     }
535 
536     QuarantineChunk(m, ptr, stack, alloc_type);
537   }
538 
Reallocate__asan::Allocator539   void *Reallocate(void *old_ptr, uptr new_size, BufferedStackTrace *stack) {
540     CHECK(old_ptr && new_size);
541     uptr p = reinterpret_cast<uptr>(old_ptr);
542     uptr chunk_beg = p - kChunkHeaderSize;
543     AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
544 
545     AsanStats &thread_stats = GetCurrentThreadStats();
546     thread_stats.reallocs++;
547     thread_stats.realloced += new_size;
548 
549     void *new_ptr = Allocate(new_size, 8, stack, FROM_MALLOC, true);
550     if (new_ptr) {
551       u8 chunk_state = m->chunk_state;
552       if (chunk_state != CHUNK_ALLOCATED)
553         ReportInvalidFree(old_ptr, chunk_state, stack);
554       CHECK_NE(REAL(memcpy), nullptr);
555       uptr memcpy_size = Min(new_size, m->UsedSize());
556       // If realloc() races with free(), we may start copying freed memory.
557       // However, we will report racy double-free later anyway.
558       REAL(memcpy)(new_ptr, old_ptr, memcpy_size);
559       Deallocate(old_ptr, 0, stack, FROM_MALLOC);
560     }
561     return new_ptr;
562   }
563 
Calloc__asan::Allocator564   void *Calloc(uptr nmemb, uptr size, BufferedStackTrace *stack) {
565     if (CallocShouldReturnNullDueToOverflow(size, nmemb))
566       return allocator.ReturnNullOrDie();
567     void *ptr = Allocate(nmemb * size, 8, stack, FROM_MALLOC, false);
568     // If the memory comes from the secondary allocator no need to clear it
569     // as it comes directly from mmap.
570     if (ptr && allocator.FromPrimary(ptr))
571       REAL(memset)(ptr, 0, nmemb * size);
572     return ptr;
573   }
574 
ReportInvalidFree__asan::Allocator575   void ReportInvalidFree(void *ptr, u8 chunk_state, BufferedStackTrace *stack) {
576     if (chunk_state == CHUNK_QUARANTINE)
577       ReportDoubleFree((uptr)ptr, stack);
578     else
579       ReportFreeNotMalloced((uptr)ptr, stack);
580   }
581 
CommitBack__asan::Allocator582   void CommitBack(AsanThreadLocalMallocStorage *ms) {
583     AllocatorCache *ac = GetAllocatorCache(ms);
584     quarantine.Drain(GetQuarantineCache(ms), QuarantineCallback(ac));
585     allocator.SwallowCache(ac);
586   }
587 
588   // -------------------------- Chunk lookup ----------------------
589 
590   // Assumes alloc_beg == allocator.GetBlockBegin(alloc_beg).
GetAsanChunk__asan::Allocator591   AsanChunk *GetAsanChunk(void *alloc_beg) {
592     if (!alloc_beg) return nullptr;
593     if (!allocator.FromPrimary(alloc_beg)) {
594       uptr *meta = reinterpret_cast<uptr *>(allocator.GetMetaData(alloc_beg));
595       AsanChunk *m = reinterpret_cast<AsanChunk *>(meta[1]);
596       return m;
597     }
598     uptr *alloc_magic = reinterpret_cast<uptr *>(alloc_beg);
599     if (alloc_magic[0] == kAllocBegMagic)
600       return reinterpret_cast<AsanChunk *>(alloc_magic[1]);
601     return reinterpret_cast<AsanChunk *>(alloc_beg);
602   }
603 
GetAsanChunkByAddr__asan::Allocator604   AsanChunk *GetAsanChunkByAddr(uptr p) {
605     void *alloc_beg = allocator.GetBlockBegin(reinterpret_cast<void *>(p));
606     return GetAsanChunk(alloc_beg);
607   }
608 
609   // Allocator must be locked when this function is called.
GetAsanChunkByAddrFastLocked__asan::Allocator610   AsanChunk *GetAsanChunkByAddrFastLocked(uptr p) {
611     void *alloc_beg =
612         allocator.GetBlockBeginFastLocked(reinterpret_cast<void *>(p));
613     return GetAsanChunk(alloc_beg);
614   }
615 
AllocationSize__asan::Allocator616   uptr AllocationSize(uptr p) {
617     AsanChunk *m = GetAsanChunkByAddr(p);
618     if (!m) return 0;
619     if (m->chunk_state != CHUNK_ALLOCATED) return 0;
620     if (m->Beg() != p) return 0;
621     return m->UsedSize();
622   }
623 
FindHeapChunkByAddress__asan::Allocator624   AsanChunkView FindHeapChunkByAddress(uptr addr) {
625     AsanChunk *m1 = GetAsanChunkByAddr(addr);
626     if (!m1) return AsanChunkView(m1);
627     sptr offset = 0;
628     if (AsanChunkView(m1).AddrIsAtLeft(addr, 1, &offset)) {
629       // The address is in the chunk's left redzone, so maybe it is actually
630       // a right buffer overflow from the other chunk to the left.
631       // Search a bit to the left to see if there is another chunk.
632       AsanChunk *m2 = nullptr;
633       for (uptr l = 1; l < GetPageSizeCached(); l++) {
634         m2 = GetAsanChunkByAddr(addr - l);
635         if (m2 == m1) continue;  // Still the same chunk.
636         break;
637       }
638       if (m2 && AsanChunkView(m2).AddrIsAtRight(addr, 1, &offset))
639         m1 = ChooseChunk(addr, m2, m1);
640     }
641     return AsanChunkView(m1);
642   }
643 
PrintStats__asan::Allocator644   void PrintStats() {
645     allocator.PrintStats();
646   }
647 
ForceLock__asan::Allocator648   void ForceLock() {
649     allocator.ForceLock();
650     fallback_mutex.Lock();
651   }
652 
ForceUnlock__asan::Allocator653   void ForceUnlock() {
654     fallback_mutex.Unlock();
655     allocator.ForceUnlock();
656   }
657 };
658 
659 static Allocator instance(LINKER_INITIALIZED);
660 
get_allocator()661 static AsanAllocator &get_allocator() {
662   return instance.allocator;
663 }
664 
IsValid()665 bool AsanChunkView::IsValid() {
666   return chunk_ && chunk_->chunk_state != CHUNK_AVAILABLE;
667 }
IsAllocated()668 bool AsanChunkView::IsAllocated() {
669   return chunk_ && chunk_->chunk_state == CHUNK_ALLOCATED;
670 }
Beg()671 uptr AsanChunkView::Beg() { return chunk_->Beg(); }
End()672 uptr AsanChunkView::End() { return Beg() + UsedSize(); }
UsedSize()673 uptr AsanChunkView::UsedSize() { return chunk_->UsedSize(); }
AllocTid()674 uptr AsanChunkView::AllocTid() { return chunk_->alloc_tid; }
FreeTid()675 uptr AsanChunkView::FreeTid() { return chunk_->free_tid; }
676 
GetStackTraceFromId(u32 id)677 static StackTrace GetStackTraceFromId(u32 id) {
678   CHECK(id);
679   StackTrace res = StackDepotGet(id);
680   CHECK(res.trace);
681   return res;
682 }
683 
GetAllocStackId()684 u32 AsanChunkView::GetAllocStackId() { return chunk_->alloc_context_id; }
GetFreeStackId()685 u32 AsanChunkView::GetFreeStackId() { return chunk_->free_context_id; }
686 
GetAllocStack()687 StackTrace AsanChunkView::GetAllocStack() {
688   return GetStackTraceFromId(GetAllocStackId());
689 }
690 
GetFreeStack()691 StackTrace AsanChunkView::GetFreeStack() {
692   return GetStackTraceFromId(GetFreeStackId());
693 }
694 
InitializeAllocator(const AllocatorOptions & options)695 void InitializeAllocator(const AllocatorOptions &options) {
696   instance.Initialize(options);
697 }
698 
ReInitializeAllocator(const AllocatorOptions & options)699 void ReInitializeAllocator(const AllocatorOptions &options) {
700   instance.ReInitialize(options);
701 }
702 
GetAllocatorOptions(AllocatorOptions * options)703 void GetAllocatorOptions(AllocatorOptions *options) {
704   instance.GetOptions(options);
705 }
706 
FindHeapChunkByAddress(uptr addr)707 AsanChunkView FindHeapChunkByAddress(uptr addr) {
708   return instance.FindHeapChunkByAddress(addr);
709 }
710 
CommitBack()711 void AsanThreadLocalMallocStorage::CommitBack() {
712   instance.CommitBack(this);
713 }
714 
PrintInternalAllocatorStats()715 void PrintInternalAllocatorStats() {
716   instance.PrintStats();
717 }
718 
asan_memalign(uptr alignment,uptr size,BufferedStackTrace * stack,AllocType alloc_type)719 void *asan_memalign(uptr alignment, uptr size, BufferedStackTrace *stack,
720                     AllocType alloc_type) {
721   return instance.Allocate(size, alignment, stack, alloc_type, true);
722 }
723 
asan_free(void * ptr,BufferedStackTrace * stack,AllocType alloc_type)724 void asan_free(void *ptr, BufferedStackTrace *stack, AllocType alloc_type) {
725   instance.Deallocate(ptr, 0, stack, alloc_type);
726 }
727 
asan_sized_free(void * ptr,uptr size,BufferedStackTrace * stack,AllocType alloc_type)728 void asan_sized_free(void *ptr, uptr size, BufferedStackTrace *stack,
729                      AllocType alloc_type) {
730   instance.Deallocate(ptr, size, stack, alloc_type);
731 }
732 
asan_malloc(uptr size,BufferedStackTrace * stack)733 void *asan_malloc(uptr size, BufferedStackTrace *stack) {
734   return instance.Allocate(size, 8, stack, FROM_MALLOC, true);
735 }
736 
asan_calloc(uptr nmemb,uptr size,BufferedStackTrace * stack)737 void *asan_calloc(uptr nmemb, uptr size, BufferedStackTrace *stack) {
738   return instance.Calloc(nmemb, size, stack);
739 }
740 
asan_realloc(void * p,uptr size,BufferedStackTrace * stack)741 void *asan_realloc(void *p, uptr size, BufferedStackTrace *stack) {
742   if (!p)
743     return instance.Allocate(size, 8, stack, FROM_MALLOC, true);
744   if (size == 0) {
745     instance.Deallocate(p, 0, stack, FROM_MALLOC);
746     return nullptr;
747   }
748   return instance.Reallocate(p, size, stack);
749 }
750 
asan_valloc(uptr size,BufferedStackTrace * stack)751 void *asan_valloc(uptr size, BufferedStackTrace *stack) {
752   return instance.Allocate(size, GetPageSizeCached(), stack, FROM_MALLOC, true);
753 }
754 
asan_pvalloc(uptr size,BufferedStackTrace * stack)755 void *asan_pvalloc(uptr size, BufferedStackTrace *stack) {
756   uptr PageSize = GetPageSizeCached();
757   size = RoundUpTo(size, PageSize);
758   if (size == 0) {
759     // pvalloc(0) should allocate one page.
760     size = PageSize;
761   }
762   return instance.Allocate(size, PageSize, stack, FROM_MALLOC, true);
763 }
764 
asan_posix_memalign(void ** memptr,uptr alignment,uptr size,BufferedStackTrace * stack)765 int asan_posix_memalign(void **memptr, uptr alignment, uptr size,
766                         BufferedStackTrace *stack) {
767   void *ptr = instance.Allocate(size, alignment, stack, FROM_MALLOC, true);
768   CHECK(IsAligned((uptr)ptr, alignment));
769   *memptr = ptr;
770   return 0;
771 }
772 
asan_malloc_usable_size(const void * ptr,uptr pc,uptr bp)773 uptr asan_malloc_usable_size(const void *ptr, uptr pc, uptr bp) {
774   if (!ptr) return 0;
775   uptr usable_size = instance.AllocationSize(reinterpret_cast<uptr>(ptr));
776   if (flags()->check_malloc_usable_size && (usable_size == 0)) {
777     GET_STACK_TRACE_FATAL(pc, bp);
778     ReportMallocUsableSizeNotOwned((uptr)ptr, &stack);
779   }
780   return usable_size;
781 }
782 
asan_mz_size(const void * ptr)783 uptr asan_mz_size(const void *ptr) {
784   return instance.AllocationSize(reinterpret_cast<uptr>(ptr));
785 }
786 
asan_mz_force_lock()787 void asan_mz_force_lock() {
788   instance.ForceLock();
789 }
790 
asan_mz_force_unlock()791 void asan_mz_force_unlock() {
792   instance.ForceUnlock();
793 }
794 
AsanSoftRssLimitExceededCallback(bool exceeded)795 void AsanSoftRssLimitExceededCallback(bool exceeded) {
796   instance.allocator.SetRssLimitIsExceeded(exceeded);
797 }
798 
799 } // namespace __asan
800 
801 // --- Implementation of LSan-specific functions --- {{{1
802 namespace __lsan {
LockAllocator()803 void LockAllocator() {
804   __asan::get_allocator().ForceLock();
805 }
806 
UnlockAllocator()807 void UnlockAllocator() {
808   __asan::get_allocator().ForceUnlock();
809 }
810 
GetAllocatorGlobalRange(uptr * begin,uptr * end)811 void GetAllocatorGlobalRange(uptr *begin, uptr *end) {
812   *begin = (uptr)&__asan::get_allocator();
813   *end = *begin + sizeof(__asan::get_allocator());
814 }
815 
PointsIntoChunk(void * p)816 uptr PointsIntoChunk(void* p) {
817   uptr addr = reinterpret_cast<uptr>(p);
818   __asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddrFastLocked(addr);
819   if (!m) return 0;
820   uptr chunk = m->Beg();
821   if (m->chunk_state != __asan::CHUNK_ALLOCATED)
822     return 0;
823   if (m->AddrIsInside(addr, /*locked_version=*/true))
824     return chunk;
825   if (IsSpecialCaseOfOperatorNew0(chunk, m->UsedSize(/*locked_version*/ true),
826                                   addr))
827     return chunk;
828   return 0;
829 }
830 
GetUserBegin(uptr chunk)831 uptr GetUserBegin(uptr chunk) {
832   __asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddrFastLocked(chunk);
833   CHECK(m);
834   return m->Beg();
835 }
836 
LsanMetadata(uptr chunk)837 LsanMetadata::LsanMetadata(uptr chunk) {
838   metadata_ = reinterpret_cast<void *>(chunk - __asan::kChunkHeaderSize);
839 }
840 
allocated() const841 bool LsanMetadata::allocated() const {
842   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
843   return m->chunk_state == __asan::CHUNK_ALLOCATED;
844 }
845 
tag() const846 ChunkTag LsanMetadata::tag() const {
847   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
848   return static_cast<ChunkTag>(m->lsan_tag);
849 }
850 
set_tag(ChunkTag value)851 void LsanMetadata::set_tag(ChunkTag value) {
852   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
853   m->lsan_tag = value;
854 }
855 
requested_size() const856 uptr LsanMetadata::requested_size() const {
857   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
858   return m->UsedSize(/*locked_version=*/true);
859 }
860 
stack_trace_id() const861 u32 LsanMetadata::stack_trace_id() const {
862   __asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
863   return m->alloc_context_id;
864 }
865 
ForEachChunk(ForEachChunkCallback callback,void * arg)866 void ForEachChunk(ForEachChunkCallback callback, void *arg) {
867   __asan::get_allocator().ForEachChunk(callback, arg);
868 }
869 
IgnoreObjectLocked(const void * p)870 IgnoreObjectResult IgnoreObjectLocked(const void *p) {
871   uptr addr = reinterpret_cast<uptr>(p);
872   __asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddr(addr);
873   if (!m) return kIgnoreObjectInvalid;
874   if ((m->chunk_state == __asan::CHUNK_ALLOCATED) && m->AddrIsInside(addr)) {
875     if (m->lsan_tag == kIgnored)
876       return kIgnoreObjectAlreadyIgnored;
877     m->lsan_tag = __lsan::kIgnored;
878     return kIgnoreObjectSuccess;
879   } else {
880     return kIgnoreObjectInvalid;
881   }
882 }
883 }  // namespace __lsan
884 
885 // ---------------------- Interface ---------------- {{{1
886 using namespace __asan;  // NOLINT
887 
888 // ASan allocator doesn't reserve extra bytes, so normally we would
889 // just return "size". We don't want to expose our redzone sizes, etc here.
__sanitizer_get_estimated_allocated_size(uptr size)890 uptr __sanitizer_get_estimated_allocated_size(uptr size) {
891   return size;
892 }
893 
__sanitizer_get_ownership(const void * p)894 int __sanitizer_get_ownership(const void *p) {
895   uptr ptr = reinterpret_cast<uptr>(p);
896   return instance.AllocationSize(ptr) > 0;
897 }
898 
__sanitizer_get_allocated_size(const void * p)899 uptr __sanitizer_get_allocated_size(const void *p) {
900   if (!p) return 0;
901   uptr ptr = reinterpret_cast<uptr>(p);
902   uptr allocated_size = instance.AllocationSize(ptr);
903   // Die if p is not malloced or if it is already freed.
904   if (allocated_size == 0) {
905     GET_STACK_TRACE_FATAL_HERE;
906     ReportSanitizerGetAllocatedSizeNotOwned(ptr, &stack);
907   }
908   return allocated_size;
909 }
910 
911 #if !SANITIZER_SUPPORTS_WEAK_HOOKS
912 // Provide default (no-op) implementation of malloc hooks.
913 extern "C" {
914 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
__sanitizer_malloc_hook(void * ptr,uptr size)915 void __sanitizer_malloc_hook(void *ptr, uptr size) {
916   (void)ptr;
917   (void)size;
918 }
919 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE
__sanitizer_free_hook(void * ptr)920 void __sanitizer_free_hook(void *ptr) {
921   (void)ptr;
922 }
923 } // extern "C"
924 #endif
925