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gcc/libsanitizer/asan/asan_allocator.cpp

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//===-- asan_allocator.cpp ------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of AddressSanitizer, an address sanity checker.
//
// Implementation of ASan's memory allocator, 2-nd version.
// This variant uses the allocator from sanitizer_common, i.e. the one shared
// with ThreadSanitizer and MemorySanitizer.
//
//===----------------------------------------------------------------------===//
#include "asan_allocator.h"
#include "asan_mapping.h"
#include "asan_poisoning.h"
#include "asan_report.h"
#include "asan_stack.h"
#include "asan_thread.h"
#include "lsan/lsan_common.h"
#include "sanitizer_common/sanitizer_allocator_checks.h"
#include "sanitizer_common/sanitizer_allocator_interface.h"
#include "sanitizer_common/sanitizer_errno.h"
#include "sanitizer_common/sanitizer_flags.h"
#include "sanitizer_common/sanitizer_internal_defs.h"
#include "sanitizer_common/sanitizer_list.h"
#include "sanitizer_common/sanitizer_quarantine.h"
#include "sanitizer_common/sanitizer_stackdepot.h"
namespace __asan {
// Valid redzone sizes are 16, 32, 64, ... 2048, so we encode them in 3 bits.
// We use adaptive redzones: for larger allocation larger redzones are used.
static u32 RZLog2Size(u32 rz_log) {
CHECK_LT(rz_log, 8);
return 16 << rz_log;
}
static u32 RZSize2Log(u32 rz_size) {
CHECK_GE(rz_size, 16);
CHECK_LE(rz_size, 2048);
CHECK(IsPowerOfTwo(rz_size));
u32 res = Log2(rz_size) - 4;
CHECK_EQ(rz_size, RZLog2Size(res));
return res;
}
static AsanAllocator &get_allocator();
static void AtomicContextStore(volatile atomic_uint64_t *atomic_context,
u32 tid, u32 stack) {
u64 context = tid;
context <<= 32;
context += stack;
atomic_store(atomic_context, context, memory_order_relaxed);
}
static void AtomicContextLoad(const volatile atomic_uint64_t *atomic_context,
u32 &tid, u32 &stack) {
u64 context = atomic_load(atomic_context, memory_order_relaxed);
stack = context;
context >>= 32;
tid = context;
}
// The memory chunk allocated from the underlying allocator looks like this:
// L L L L L L H H U U U U U U R R
// L -- left redzone words (0 or more bytes)
// H -- ChunkHeader (16 bytes), which is also a part of the left redzone.
// U -- user memory.
// R -- right redzone (0 or more bytes)
// ChunkBase consists of ChunkHeader and other bytes that overlap with user
// memory.
// If the left redzone is greater than the ChunkHeader size we store a magic
// value in the first uptr word of the memory block and store the address of
// ChunkBase in the next uptr.
// M B L L L L L L L L L H H U U U U U U
// | ^
// ---------------------|
// M -- magic value kAllocBegMagic
// B -- address of ChunkHeader pointing to the first 'H'
class ChunkHeader {
public:
atomic_uint8_t chunk_state;
u8 alloc_type : 2;
u8 lsan_tag : 2;
// align < 8 -> 0
// else -> log2(min(align, 512)) - 2
u8 user_requested_alignment_log : 3;
private:
u16 user_requested_size_hi;
u32 user_requested_size_lo;
atomic_uint64_t alloc_context_id;
public:
uptr UsedSize() const {
uptr R = user_requested_size_lo;
if (sizeof(uptr) > sizeof(user_requested_size_lo))
R += (uptr)user_requested_size_hi << (8 * sizeof(user_requested_size_lo));
return R;
}
void SetUsedSize(uptr size) {
user_requested_size_lo = size;
if (sizeof(uptr) > sizeof(user_requested_size_lo)) {
size >>= (8 * sizeof(user_requested_size_lo));
user_requested_size_hi = size;
CHECK_EQ(user_requested_size_hi, size);
}
}
void SetAllocContext(u32 tid, u32 stack) {
AtomicContextStore(&alloc_context_id, tid, stack);
}
void GetAllocContext(u32 &tid, u32 &stack) const {
AtomicContextLoad(&alloc_context_id, tid, stack);
}
};
class ChunkBase : public ChunkHeader {
atomic_uint64_t free_context_id;
public:
void SetFreeContext(u32 tid, u32 stack) {
AtomicContextStore(&free_context_id, tid, stack);
}
void GetFreeContext(u32 &tid, u32 &stack) const {
AtomicContextLoad(&free_context_id, tid, stack);
}
};
static const uptr kChunkHeaderSize = sizeof(ChunkHeader);
static const uptr kChunkHeader2Size = sizeof(ChunkBase) - kChunkHeaderSize;
COMPILER_CHECK(kChunkHeaderSize == 16);
COMPILER_CHECK(kChunkHeader2Size <= 16);
enum {
// Either just allocated by underlying allocator, but AsanChunk is not yet
// ready, or almost returned to undelying allocator and AsanChunk is already
// meaningless.
CHUNK_INVALID = 0,
// The chunk is allocated and not yet freed.
CHUNK_ALLOCATED = 2,
// The chunk was freed and put into quarantine zone.
CHUNK_QUARANTINE = 3,
};
class AsanChunk : public ChunkBase {
public:
uptr Beg() { return reinterpret_cast<uptr>(this) + kChunkHeaderSize; }
bool AddrIsInside(uptr addr) {
return (addr >= Beg()) && (addr < Beg() + UsedSize());
}
};
class LargeChunkHeader {
static constexpr uptr kAllocBegMagic =
FIRST_32_SECOND_64(0xCC6E96B9, 0xCC6E96B9CC6E96B9ULL);
atomic_uintptr_t magic;
AsanChunk *chunk_header;
public:
AsanChunk *Get() const {
return atomic_load(&magic, memory_order_acquire) == kAllocBegMagic
? chunk_header
: nullptr;
}
void Set(AsanChunk *p) {
if (p) {
chunk_header = p;
atomic_store(&magic, kAllocBegMagic, memory_order_release);
return;
}
uptr old = kAllocBegMagic;
if (!atomic_compare_exchange_strong(&magic, &old, 0,
memory_order_release)) {
CHECK_EQ(old, kAllocBegMagic);
}
}
};
struct QuarantineCallback {
QuarantineCallback(AllocatorCache *cache, BufferedStackTrace *stack)
: cache_(cache),
stack_(stack) {
}
void Recycle(AsanChunk *m) {
void *p = get_allocator().GetBlockBegin(m);
if (p != m) {
// Clear the magic value, as allocator internals may overwrite the
// contents of deallocated chunk, confusing GetAsanChunk lookup.
reinterpret_cast<LargeChunkHeader *>(p)->Set(nullptr);
}
u8 old_chunk_state = CHUNK_QUARANTINE;
if (!atomic_compare_exchange_strong(&m->chunk_state, &old_chunk_state,
CHUNK_INVALID, memory_order_acquire)) {
CHECK_EQ(old_chunk_state, CHUNK_QUARANTINE);
}
PoisonShadow(m->Beg(),
RoundUpTo(m->UsedSize(), SHADOW_GRANULARITY),
kAsanHeapLeftRedzoneMagic);
// Statistics.
AsanStats &thread_stats = GetCurrentThreadStats();
thread_stats.real_frees++;
thread_stats.really_freed += m->UsedSize();
get_allocator().Deallocate(cache_, p);
}
void *Allocate(uptr size) {
void *res = get_allocator().Allocate(cache_, size, 1);
// TODO(alekseys): Consider making quarantine OOM-friendly.
if (UNLIKELY(!res))
ReportOutOfMemory(size, stack_);
return res;
}
void Deallocate(void *p) {
get_allocator().Deallocate(cache_, p);
}
private:
AllocatorCache* const cache_;
BufferedStackTrace* const stack_;
};
typedef Quarantine<QuarantineCallback, AsanChunk> AsanQuarantine;
typedef AsanQuarantine::Cache QuarantineCache;
void AsanMapUnmapCallback::OnMap(uptr p, uptr size) const {
PoisonShadow(p, size, kAsanHeapLeftRedzoneMagic);
// Statistics.
AsanStats &thread_stats = GetCurrentThreadStats();
thread_stats.mmaps++;
thread_stats.mmaped += size;
}
void AsanMapUnmapCallback::OnUnmap(uptr p, uptr size) const {
PoisonShadow(p, size, 0);
// We are about to unmap a chunk of user memory.
// Mark the corresponding shadow memory as not needed.
FlushUnneededASanShadowMemory(p, size);
// Statistics.
AsanStats &thread_stats = GetCurrentThreadStats();
thread_stats.munmaps++;
thread_stats.munmaped += size;
}
// We can not use THREADLOCAL because it is not supported on some of the
// platforms we care about (OSX 10.6, Android).
// static THREADLOCAL AllocatorCache cache;
AllocatorCache *GetAllocatorCache(AsanThreadLocalMallocStorage *ms) {
CHECK(ms);
return &ms->allocator_cache;
}
QuarantineCache *GetQuarantineCache(AsanThreadLocalMallocStorage *ms) {
CHECK(ms);
CHECK_LE(sizeof(QuarantineCache), sizeof(ms->quarantine_cache));
return reinterpret_cast<QuarantineCache *>(ms->quarantine_cache);
}
void AllocatorOptions::SetFrom(const Flags *f, const CommonFlags *cf) {
quarantine_size_mb = f->quarantine_size_mb;
thread_local_quarantine_size_kb = f->thread_local_quarantine_size_kb;
min_redzone = f->redzone;
max_redzone = f->max_redzone;
may_return_null = cf->allocator_may_return_null;
alloc_dealloc_mismatch = f->alloc_dealloc_mismatch;
release_to_os_interval_ms = cf->allocator_release_to_os_interval_ms;
}
void AllocatorOptions::CopyTo(Flags *f, CommonFlags *cf) {
f->quarantine_size_mb = quarantine_size_mb;
f->thread_local_quarantine_size_kb = thread_local_quarantine_size_kb;
f->redzone = min_redzone;
f->max_redzone = max_redzone;
cf->allocator_may_return_null = may_return_null;
f->alloc_dealloc_mismatch = alloc_dealloc_mismatch;
cf->allocator_release_to_os_interval_ms = release_to_os_interval_ms;
}
struct Allocator {
static const uptr kMaxAllowedMallocSize =
FIRST_32_SECOND_64(3UL << 30, 1ULL << 40);
AsanAllocator allocator;
AsanQuarantine quarantine;
StaticSpinMutex fallback_mutex;
AllocatorCache fallback_allocator_cache;
QuarantineCache fallback_quarantine_cache;
uptr max_user_defined_malloc_size;
atomic_uint8_t rss_limit_exceeded;
// ------------------- Options --------------------------
atomic_uint16_t min_redzone;
atomic_uint16_t max_redzone;
atomic_uint8_t alloc_dealloc_mismatch;
// ------------------- Initialization ------------------------
explicit Allocator(LinkerInitialized)
: quarantine(LINKER_INITIALIZED),
fallback_quarantine_cache(LINKER_INITIALIZED) {}
void CheckOptions(const AllocatorOptions &options) const {
CHECK_GE(options.min_redzone, 16);
CHECK_GE(options.max_redzone, options.min_redzone);
CHECK_LE(options.max_redzone, 2048);
CHECK(IsPowerOfTwo(options.min_redzone));
CHECK(IsPowerOfTwo(options.max_redzone));
}
void SharedInitCode(const AllocatorOptions &options) {
CheckOptions(options);
quarantine.Init((uptr)options.quarantine_size_mb << 20,
(uptr)options.thread_local_quarantine_size_kb << 10);
atomic_store(&alloc_dealloc_mismatch, options.alloc_dealloc_mismatch,
memory_order_release);
atomic_store(&min_redzone, options.min_redzone, memory_order_release);
atomic_store(&max_redzone, options.max_redzone, memory_order_release);
}
void InitLinkerInitialized(const AllocatorOptions &options) {
SetAllocatorMayReturnNull(options.may_return_null);
allocator.InitLinkerInitialized(options.release_to_os_interval_ms);
SharedInitCode(options);
max_user_defined_malloc_size = common_flags()->max_allocation_size_mb
? common_flags()->max_allocation_size_mb
<< 20
: kMaxAllowedMallocSize;
}
bool RssLimitExceeded() {
return atomic_load(&rss_limit_exceeded, memory_order_relaxed);
}
void SetRssLimitExceeded(bool limit_exceeded) {
atomic_store(&rss_limit_exceeded, limit_exceeded, memory_order_relaxed);
}
void RePoisonChunk(uptr chunk) {
// This could be a user-facing chunk (with redzones), or some internal
// housekeeping chunk, like TransferBatch. Start by assuming the former.
AsanChunk *ac = GetAsanChunk((void *)chunk);
uptr allocated_size = allocator.GetActuallyAllocatedSize((void *)chunk);
if (ac && atomic_load(&ac->chunk_state, memory_order_acquire) ==
CHUNK_ALLOCATED) {
uptr beg = ac->Beg();
uptr end = ac->Beg() + ac->UsedSize();
uptr chunk_end = chunk + allocated_size;
if (chunk < beg && beg < end && end <= chunk_end) {
// Looks like a valid AsanChunk in use, poison redzones only.
PoisonShadow(chunk, beg - chunk, kAsanHeapLeftRedzoneMagic);
uptr end_aligned_down = RoundDownTo(end, SHADOW_GRANULARITY);
FastPoisonShadowPartialRightRedzone(
end_aligned_down, end - end_aligned_down,
chunk_end - end_aligned_down, kAsanHeapLeftRedzoneMagic);
return;
}
}
// This is either not an AsanChunk or freed or quarantined AsanChunk.
// In either case, poison everything.
PoisonShadow(chunk, allocated_size, kAsanHeapLeftRedzoneMagic);
}
void ReInitialize(const AllocatorOptions &options) {
SetAllocatorMayReturnNull(options.may_return_null);
allocator.SetReleaseToOSIntervalMs(options.release_to_os_interval_ms);
SharedInitCode(options);
// Poison all existing allocation's redzones.
if (CanPoisonMemory()) {
allocator.ForceLock();
allocator.ForEachChunk(
[](uptr chunk, void *alloc) {
((Allocator *)alloc)->RePoisonChunk(chunk);
},
this);
allocator.ForceUnlock();
}
}
void GetOptions(AllocatorOptions *options) const {
options->quarantine_size_mb = quarantine.GetSize() >> 20;
options->thread_local_quarantine_size_kb = quarantine.GetCacheSize() >> 10;
options->min_redzone = atomic_load(&min_redzone, memory_order_acquire);
options->max_redzone = atomic_load(&max_redzone, memory_order_acquire);
options->may_return_null = AllocatorMayReturnNull();
options->alloc_dealloc_mismatch =
atomic_load(&alloc_dealloc_mismatch, memory_order_acquire);
options->release_to_os_interval_ms = allocator.ReleaseToOSIntervalMs();
}
// -------------------- Helper methods. -------------------------
uptr ComputeRZLog(uptr user_requested_size) {
u32 rz_log = user_requested_size <= 64 - 16 ? 0
: user_requested_size <= 128 - 32 ? 1
: user_requested_size <= 512 - 64 ? 2
: user_requested_size <= 4096 - 128 ? 3
: user_requested_size <= (1 << 14) - 256 ? 4
: user_requested_size <= (1 << 15) - 512 ? 5
: user_requested_size <= (1 << 16) - 1024 ? 6
: 7;
u32 hdr_log = RZSize2Log(RoundUpToPowerOfTwo(sizeof(ChunkHeader)));
u32 min_log = RZSize2Log(atomic_load(&min_redzone, memory_order_acquire));
u32 max_log = RZSize2Log(atomic_load(&max_redzone, memory_order_acquire));
return Min(Max(rz_log, Max(min_log, hdr_log)), Max(max_log, hdr_log));
}
static uptr ComputeUserRequestedAlignmentLog(uptr user_requested_alignment) {
if (user_requested_alignment < 8)
return 0;
if (user_requested_alignment > 512)
user_requested_alignment = 512;
return Log2(user_requested_alignment) - 2;
}
static uptr ComputeUserAlignment(uptr user_requested_alignment_log) {
if (user_requested_alignment_log == 0)
return 0;
return 1LL << (user_requested_alignment_log + 2);
}
// We have an address between two chunks, and we want to report just one.
AsanChunk *ChooseChunk(uptr addr, AsanChunk *left_chunk,
AsanChunk *right_chunk) {
if (!left_chunk)
return right_chunk;
if (!right_chunk)
return left_chunk;
// Prefer an allocated chunk over freed chunk and freed chunk
// over available chunk.
u8 left_state = atomic_load(&left_chunk->chunk_state, memory_order_relaxed);
u8 right_state =
atomic_load(&right_chunk->chunk_state, memory_order_relaxed);
if (left_state != right_state) {
if (left_state == CHUNK_ALLOCATED)
return left_chunk;
if (right_state == CHUNK_ALLOCATED)
return right_chunk;
if (left_state == CHUNK_QUARANTINE)
return left_chunk;
if (right_state == CHUNK_QUARANTINE)
return right_chunk;
}
// Same chunk_state: choose based on offset.
sptr l_offset = 0, r_offset = 0;
CHECK(AsanChunkView(left_chunk).AddrIsAtRight(addr, 1, &l_offset));
CHECK(AsanChunkView(right_chunk).AddrIsAtLeft(addr, 1, &r_offset));
if (l_offset < r_offset)
return left_chunk;
return right_chunk;
}
bool UpdateAllocationStack(uptr addr, BufferedStackTrace *stack) {
AsanChunk *m = GetAsanChunkByAddr(addr);
if (!m) return false;
if (atomic_load(&m->chunk_state, memory_order_acquire) != CHUNK_ALLOCATED)
return false;
if (m->Beg() != addr) return false;
AsanThread *t = GetCurrentThread();
m->SetAllocContext(t ? t->tid() : kMainTid, StackDepotPut(*stack));
return true;
}
// -------------------- Allocation/Deallocation routines ---------------
void *Allocate(uptr size, uptr alignment, BufferedStackTrace *stack,
AllocType alloc_type, bool can_fill) {
if (UNLIKELY(!asan_inited))
AsanInitFromRtl();
if (RssLimitExceeded()) {
if (AllocatorMayReturnNull())
return nullptr;
ReportRssLimitExceeded(stack);
}
Flags &fl = *flags();
CHECK(stack);
const uptr min_alignment = SHADOW_GRANULARITY;
const uptr user_requested_alignment_log =
ComputeUserRequestedAlignmentLog(alignment);
if (alignment < min_alignment)
alignment = min_alignment;
if (size == 0) {
// We'd be happy to avoid allocating memory for zero-size requests, but
// some programs/tests depend on this behavior and assume that malloc
// would not return NULL even for zero-size allocations. Moreover, it
// looks like operator new should never return NULL, and results of
// consecutive "new" calls must be different even if the allocated size
// is zero.
size = 1;
}
CHECK(IsPowerOfTwo(alignment));
uptr rz_log = ComputeRZLog(size);
uptr rz_size = RZLog2Size(rz_log);
uptr rounded_size = RoundUpTo(Max(size, kChunkHeader2Size), alignment);
uptr needed_size = rounded_size + rz_size;
if (alignment > min_alignment)
needed_size += alignment;
// If we are allocating from the secondary allocator, there will be no
// automatic right redzone, so add the right redzone manually.
if (!PrimaryAllocator::CanAllocate(needed_size, alignment))
needed_size += rz_size;
CHECK(IsAligned(needed_size, min_alignment));
if (size > kMaxAllowedMallocSize || needed_size > kMaxAllowedMallocSize ||
size > max_user_defined_malloc_size) {
if (AllocatorMayReturnNull()) {
Report("WARNING: AddressSanitizer failed to allocate 0x%zx bytes\n",
size);
return nullptr;
}
uptr malloc_limit =
Min(kMaxAllowedMallocSize, max_user_defined_malloc_size);
ReportAllocationSizeTooBig(size, needed_size, malloc_limit, stack);
}
AsanThread *t = GetCurrentThread();
void *allocated;
if (t) {
AllocatorCache *cache = GetAllocatorCache(&t->malloc_storage());
allocated = allocator.Allocate(cache, needed_size, 8);
} else {
SpinMutexLock l(&fallback_mutex);
AllocatorCache *cache = &fallback_allocator_cache;
allocated = allocator.Allocate(cache, needed_size, 8);
}
if (UNLIKELY(!allocated)) {
SetAllocatorOutOfMemory();
if (AllocatorMayReturnNull())
return nullptr;
ReportOutOfMemory(size, stack);
}
if (*(u8 *)MEM_TO_SHADOW((uptr)allocated) == 0 && CanPoisonMemory()) {
// Heap poisoning is enabled, but the allocator provides an unpoisoned
// chunk. This is possible if CanPoisonMemory() was false for some
// time, for example, due to flags()->start_disabled.
// Anyway, poison the block before using it for anything else.
uptr allocated_size = allocator.GetActuallyAllocatedSize(allocated);
PoisonShadow((uptr)allocated, allocated_size, kAsanHeapLeftRedzoneMagic);
}
uptr alloc_beg = reinterpret_cast<uptr>(allocated);
uptr alloc_end = alloc_beg + needed_size;
uptr user_beg = alloc_beg + rz_size;
if (!IsAligned(user_beg, alignment))
user_beg = RoundUpTo(user_beg, alignment);
uptr user_end = user_beg + size;
CHECK_LE(user_end, alloc_end);
uptr chunk_beg = user_beg - kChunkHeaderSize;
AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
m->alloc_type = alloc_type;
CHECK(size);
m->SetUsedSize(size);
m->user_requested_alignment_log = user_requested_alignment_log;
m->SetAllocContext(t ? t->tid() : kMainTid, StackDepotPut(*stack));
uptr size_rounded_down_to_granularity =
RoundDownTo(size, SHADOW_GRANULARITY);
// Unpoison the bulk of the memory region.
if (size_rounded_down_to_granularity)
PoisonShadow(user_beg, size_rounded_down_to_granularity, 0);
// Deal with the end of the region if size is not aligned to granularity.
if (size != size_rounded_down_to_granularity && CanPoisonMemory()) {
u8 *shadow =
(u8 *)MemToShadow(user_beg + size_rounded_down_to_granularity);
*shadow = fl.poison_partial ? (size & (SHADOW_GRANULARITY - 1)) : 0;
}
AsanStats &thread_stats = GetCurrentThreadStats();
thread_stats.mallocs++;
thread_stats.malloced += size;
thread_stats.malloced_redzones += needed_size - size;
if (needed_size > SizeClassMap::kMaxSize)
thread_stats.malloc_large++;
else
thread_stats.malloced_by_size[SizeClassMap::ClassID(needed_size)]++;
void *res = reinterpret_cast<void *>(user_beg);
if (can_fill && fl.max_malloc_fill_size) {
uptr fill_size = Min(size, (uptr)fl.max_malloc_fill_size);
REAL(memset)(res, fl.malloc_fill_byte, fill_size);
}
#if CAN_SANITIZE_LEAKS
m->lsan_tag = __lsan::DisabledInThisThread() ? __lsan::kIgnored
: __lsan::kDirectlyLeaked;
#endif
// Must be the last mutation of metadata in this function.
atomic_store(&m->chunk_state, CHUNK_ALLOCATED, memory_order_release);
if (alloc_beg != chunk_beg) {
CHECK_LE(alloc_beg + sizeof(LargeChunkHeader), chunk_beg);
reinterpret_cast<LargeChunkHeader *>(alloc_beg)->Set(m);
}
ASAN_MALLOC_HOOK(res, size);
return res;
}
// Set quarantine flag if chunk is allocated, issue ASan error report on
// available and quarantined chunks. Return true on success, false otherwise.
bool AtomicallySetQuarantineFlagIfAllocated(AsanChunk *m, void *ptr,
BufferedStackTrace *stack) {
u8 old_chunk_state = CHUNK_ALLOCATED;
// Flip the chunk_state atomically to avoid race on double-free.
if (!atomic_compare_exchange_strong(&m->chunk_state, &old_chunk_state,
CHUNK_QUARANTINE,
memory_order_acquire)) {
ReportInvalidFree(ptr, old_chunk_state, stack);
// It's not safe to push a chunk in quarantine on invalid free.
return false;
}
CHECK_EQ(CHUNK_ALLOCATED, old_chunk_state);
// It was a user data.
m->SetFreeContext(kInvalidTid, 0);
return true;
}
// Expects the chunk to already be marked as quarantined by using
// AtomicallySetQuarantineFlagIfAllocated.
void QuarantineChunk(AsanChunk *m, void *ptr, BufferedStackTrace *stack) {
CHECK_EQ(atomic_load(&m->chunk_state, memory_order_relaxed),
CHUNK_QUARANTINE);
AsanThread *t = GetCurrentThread();
m->SetFreeContext(t ? t->tid() : 0, StackDepotPut(*stack));
Flags &fl = *flags();
if (fl.max_free_fill_size > 0) {
// We have to skip the chunk header, it contains free_context_id.
uptr scribble_start = (uptr)m + kChunkHeaderSize + kChunkHeader2Size;
if (m->UsedSize() >= kChunkHeader2Size) { // Skip Header2 in user area.
uptr size_to_fill = m->UsedSize() - kChunkHeader2Size;
size_to_fill = Min(size_to_fill, (uptr)fl.max_free_fill_size);
REAL(memset)((void *)scribble_start, fl.free_fill_byte, size_to_fill);
}
}
// Poison the region.
PoisonShadow(m->Beg(),
RoundUpTo(m->UsedSize(), SHADOW_GRANULARITY),
kAsanHeapFreeMagic);
AsanStats &thread_stats = GetCurrentThreadStats();
thread_stats.frees++;
thread_stats.freed += m->UsedSize();
// Push into quarantine.
if (t) {
AsanThreadLocalMallocStorage *ms = &t->malloc_storage();
AllocatorCache *ac = GetAllocatorCache(ms);
quarantine.Put(GetQuarantineCache(ms), QuarantineCallback(ac, stack), m,
m->UsedSize());
} else {
SpinMutexLock l(&fallback_mutex);
AllocatorCache *ac = &fallback_allocator_cache;
quarantine.Put(&fallback_quarantine_cache, QuarantineCallback(ac, stack),
m, m->UsedSize());
}
}
void Deallocate(void *ptr, uptr delete_size, uptr delete_alignment,
BufferedStackTrace *stack, AllocType alloc_type) {
uptr p = reinterpret_cast<uptr>(ptr);
if (p == 0) return;
uptr chunk_beg = p - kChunkHeaderSize;
AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
// On Windows, uninstrumented DLLs may allocate memory before ASan hooks
// malloc. Don't report an invalid free in this case.
if (SANITIZER_WINDOWS &&
!get_allocator().PointerIsMine(ptr)) {
if (!IsSystemHeapAddress(p))
ReportFreeNotMalloced(p, stack);
return;
}
ASAN_FREE_HOOK(ptr);
// Must mark the chunk as quarantined before any changes to its metadata.
// Do not quarantine given chunk if we failed to set CHUNK_QUARANTINE flag.
if (!AtomicallySetQuarantineFlagIfAllocated(m, ptr, stack)) return;
if (m->alloc_type != alloc_type) {
if (atomic_load(&alloc_dealloc_mismatch, memory_order_acquire)) {
ReportAllocTypeMismatch((uptr)ptr, stack, (AllocType)m->alloc_type,
(AllocType)alloc_type);
}
} else {
if (flags()->new_delete_type_mismatch &&
(alloc_type == FROM_NEW || alloc_type == FROM_NEW_BR) &&
((delete_size && delete_size != m->UsedSize()) ||
ComputeUserRequestedAlignmentLog(delete_alignment) !=
m->user_requested_alignment_log)) {
ReportNewDeleteTypeMismatch(p, delete_size, delete_alignment, stack);
}
}
QuarantineChunk(m, ptr, stack);
}
void *Reallocate(void *old_ptr, uptr new_size, BufferedStackTrace *stack) {
CHECK(old_ptr && new_size);
uptr p = reinterpret_cast<uptr>(old_ptr);
uptr chunk_beg = p - kChunkHeaderSize;
AsanChunk *m = reinterpret_cast<AsanChunk *>(chunk_beg);
AsanStats &thread_stats = GetCurrentThreadStats();
thread_stats.reallocs++;
thread_stats.realloced += new_size;
void *new_ptr = Allocate(new_size, 8, stack, FROM_MALLOC, true);
if (new_ptr) {
u8 chunk_state = atomic_load(&m->chunk_state, memory_order_acquire);
if (chunk_state != CHUNK_ALLOCATED)
ReportInvalidFree(old_ptr, chunk_state, stack);
CHECK_NE(REAL(memcpy), nullptr);
uptr memcpy_size = Min(new_size, m->UsedSize());
// If realloc() races with free(), we may start copying freed memory.
// However, we will report racy double-free later anyway.
REAL(memcpy)(new_ptr, old_ptr, memcpy_size);
Deallocate(old_ptr, 0, 0, stack, FROM_MALLOC);
}
return new_ptr;
}
void *Calloc(uptr nmemb, uptr size, BufferedStackTrace *stack) {
if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) {
if (AllocatorMayReturnNull())
return nullptr;
ReportCallocOverflow(nmemb, size, stack);
}
void *ptr = Allocate(nmemb * size, 8, stack, FROM_MALLOC, false);
// If the memory comes from the secondary allocator no need to clear it
// as it comes directly from mmap.
if (ptr && allocator.FromPrimary(ptr))
REAL(memset)(ptr, 0, nmemb * size);
return ptr;
}
void ReportInvalidFree(void *ptr, u8 chunk_state, BufferedStackTrace *stack) {
if (chunk_state == CHUNK_QUARANTINE)
ReportDoubleFree((uptr)ptr, stack);
else
ReportFreeNotMalloced((uptr)ptr, stack);
}
void CommitBack(AsanThreadLocalMallocStorage *ms, BufferedStackTrace *stack) {
AllocatorCache *ac = GetAllocatorCache(ms);
quarantine.Drain(GetQuarantineCache(ms), QuarantineCallback(ac, stack));
allocator.SwallowCache(ac);
}
// -------------------------- Chunk lookup ----------------------
// Assumes alloc_beg == allocator.GetBlockBegin(alloc_beg).
// Returns nullptr if AsanChunk is not yet initialized just after
// get_allocator().Allocate(), or is being destroyed just before
// get_allocator().Deallocate().
AsanChunk *GetAsanChunk(void *alloc_beg) {
if (!alloc_beg)
return nullptr;
AsanChunk *p = reinterpret_cast<LargeChunkHeader *>(alloc_beg)->Get();
if (!p) {
if (!allocator.FromPrimary(alloc_beg))
return nullptr;
p = reinterpret_cast<AsanChunk *>(alloc_beg);
}
u8 state = atomic_load(&p->chunk_state, memory_order_relaxed);
// It does not guaranty that Chunk is initialized, but it's
// definitely not for any other value.
if (state == CHUNK_ALLOCATED || state == CHUNK_QUARANTINE)
return p;
return nullptr;
}
AsanChunk *GetAsanChunkByAddr(uptr p) {
void *alloc_beg = allocator.GetBlockBegin(reinterpret_cast<void *>(p));
return GetAsanChunk(alloc_beg);
}
// Allocator must be locked when this function is called.
AsanChunk *GetAsanChunkByAddrFastLocked(uptr p) {
void *alloc_beg =
allocator.GetBlockBeginFastLocked(reinterpret_cast<void *>(p));
return GetAsanChunk(alloc_beg);
}
uptr AllocationSize(uptr p) {
AsanChunk *m = GetAsanChunkByAddr(p);
if (!m) return 0;
if (atomic_load(&m->chunk_state, memory_order_acquire) != CHUNK_ALLOCATED)
return 0;
if (m->Beg() != p) return 0;
return m->UsedSize();
}
AsanChunkView FindHeapChunkByAddress(uptr addr) {
AsanChunk *m1 = GetAsanChunkByAddr(addr);
sptr offset = 0;
if (!m1 || AsanChunkView(m1).AddrIsAtLeft(addr, 1, &offset)) {
// The address is in the chunk's left redzone, so maybe it is actually
// a right buffer overflow from the other chunk to the left.
// Search a bit to the left to see if there is another chunk.
AsanChunk *m2 = nullptr;
for (uptr l = 1; l < GetPageSizeCached(); l++) {
m2 = GetAsanChunkByAddr(addr - l);
if (m2 == m1) continue; // Still the same chunk.
break;
}
if (m2 && AsanChunkView(m2).AddrIsAtRight(addr, 1, &offset))
m1 = ChooseChunk(addr, m2, m1);
}
return AsanChunkView(m1);
}
void Purge(BufferedStackTrace *stack) {
AsanThread *t = GetCurrentThread();
if (t) {
AsanThreadLocalMallocStorage *ms = &t->malloc_storage();
quarantine.DrainAndRecycle(GetQuarantineCache(ms),
QuarantineCallback(GetAllocatorCache(ms),
stack));
}
{
SpinMutexLock l(&fallback_mutex);
quarantine.DrainAndRecycle(&fallback_quarantine_cache,
QuarantineCallback(&fallback_allocator_cache,
stack));
}
allocator.ForceReleaseToOS();
}
void PrintStats() {
allocator.PrintStats();
quarantine.PrintStats();
}
void ForceLock() ACQUIRE(fallback_mutex) {
allocator.ForceLock();
fallback_mutex.Lock();
}
void ForceUnlock() RELEASE(fallback_mutex) {
fallback_mutex.Unlock();
allocator.ForceUnlock();
}
};
static Allocator instance(LINKER_INITIALIZED);
static AsanAllocator &get_allocator() {
return instance.allocator;
}
bool AsanChunkView::IsValid() const {
return chunk_ && atomic_load(&chunk_->chunk_state, memory_order_relaxed) !=
CHUNK_INVALID;
}
bool AsanChunkView::IsAllocated() const {
return chunk_ && atomic_load(&chunk_->chunk_state, memory_order_relaxed) ==
CHUNK_ALLOCATED;
}
bool AsanChunkView::IsQuarantined() const {
return chunk_ && atomic_load(&chunk_->chunk_state, memory_order_relaxed) ==
CHUNK_QUARANTINE;
}
uptr AsanChunkView::Beg() const { return chunk_->Beg(); }
uptr AsanChunkView::End() const { return Beg() + UsedSize(); }
uptr AsanChunkView::UsedSize() const { return chunk_->UsedSize(); }
u32 AsanChunkView::UserRequestedAlignment() const {
return Allocator::ComputeUserAlignment(chunk_->user_requested_alignment_log);
}
uptr AsanChunkView::AllocTid() const {
u32 tid = 0;
u32 stack = 0;
chunk_->GetAllocContext(tid, stack);
return tid;
}
uptr AsanChunkView::FreeTid() const {
if (!IsQuarantined())
return kInvalidTid;
u32 tid = 0;
u32 stack = 0;
chunk_->GetFreeContext(tid, stack);
return tid;
}
AllocType AsanChunkView::GetAllocType() const {
return (AllocType)chunk_->alloc_type;
}
u32 AsanChunkView::GetAllocStackId() const {
u32 tid = 0;
u32 stack = 0;
chunk_->GetAllocContext(tid, stack);
return stack;
}
u32 AsanChunkView::GetFreeStackId() const {
if (!IsQuarantined())
return 0;
u32 tid = 0;
u32 stack = 0;
chunk_->GetFreeContext(tid, stack);
return stack;
}
void InitializeAllocator(const AllocatorOptions &options) {
instance.InitLinkerInitialized(options);
}
void ReInitializeAllocator(const AllocatorOptions &options) {
instance.ReInitialize(options);
}
void GetAllocatorOptions(AllocatorOptions *options) {
instance.GetOptions(options);
}
AsanChunkView FindHeapChunkByAddress(uptr addr) {
return instance.FindHeapChunkByAddress(addr);
}
AsanChunkView FindHeapChunkByAllocBeg(uptr addr) {
return AsanChunkView(instance.GetAsanChunk(reinterpret_cast<void*>(addr)));
}
void AsanThreadLocalMallocStorage::CommitBack() {
GET_STACK_TRACE_MALLOC;
instance.CommitBack(this, &stack);
}
void PrintInternalAllocatorStats() {
instance.PrintStats();
}
void asan_free(void *ptr, BufferedStackTrace *stack, AllocType alloc_type) {
instance.Deallocate(ptr, 0, 0, stack, alloc_type);
}
void asan_delete(void *ptr, uptr size, uptr alignment,
BufferedStackTrace *stack, AllocType alloc_type) {
instance.Deallocate(ptr, size, alignment, stack, alloc_type);
}
void *asan_malloc(uptr size, BufferedStackTrace *stack) {
return SetErrnoOnNull(instance.Allocate(size, 8, stack, FROM_MALLOC, true));
}
void *asan_calloc(uptr nmemb, uptr size, BufferedStackTrace *stack) {
return SetErrnoOnNull(instance.Calloc(nmemb, size, stack));
}
void *asan_reallocarray(void *p, uptr nmemb, uptr size,
BufferedStackTrace *stack) {
if (UNLIKELY(CheckForCallocOverflow(size, nmemb))) {
errno = errno_ENOMEM;
if (AllocatorMayReturnNull())
return nullptr;
ReportReallocArrayOverflow(nmemb, size, stack);
}
return asan_realloc(p, nmemb * size, stack);
}
void *asan_realloc(void *p, uptr size, BufferedStackTrace *stack) {
if (!p)
return SetErrnoOnNull(instance.Allocate(size, 8, stack, FROM_MALLOC, true));
if (size == 0) {
if (flags()->allocator_frees_and_returns_null_on_realloc_zero) {
instance.Deallocate(p, 0, 0, stack, FROM_MALLOC);
return nullptr;
}
// Allocate a size of 1 if we shouldn't free() on Realloc to 0
size = 1;
}
return SetErrnoOnNull(instance.Reallocate(p, size, stack));
}
void *asan_valloc(uptr size, BufferedStackTrace *stack) {
return SetErrnoOnNull(
instance.Allocate(size, GetPageSizeCached(), stack, FROM_MALLOC, true));
}
void *asan_pvalloc(uptr size, BufferedStackTrace *stack) {
uptr PageSize = GetPageSizeCached();
if (UNLIKELY(CheckForPvallocOverflow(size, PageSize))) {
errno = errno_ENOMEM;
if (AllocatorMayReturnNull())
return nullptr;
ReportPvallocOverflow(size, stack);
}
// pvalloc(0) should allocate one page.
size = size ? RoundUpTo(size, PageSize) : PageSize;
return SetErrnoOnNull(
instance.Allocate(size, PageSize, stack, FROM_MALLOC, true));
}
void *asan_memalign(uptr alignment, uptr size, BufferedStackTrace *stack,
AllocType alloc_type) {
if (UNLIKELY(!IsPowerOfTwo(alignment))) {
errno = errno_EINVAL;
if (AllocatorMayReturnNull())
return nullptr;
ReportInvalidAllocationAlignment(alignment, stack);
}
return SetErrnoOnNull(
instance.Allocate(size, alignment, stack, alloc_type, true));
}
void *asan_aligned_alloc(uptr alignment, uptr size, BufferedStackTrace *stack) {
if (UNLIKELY(!CheckAlignedAllocAlignmentAndSize(alignment, size))) {
errno = errno_EINVAL;
if (AllocatorMayReturnNull())
return nullptr;
ReportInvalidAlignedAllocAlignment(size, alignment, stack);
}
return SetErrnoOnNull(
instance.Allocate(size, alignment, stack, FROM_MALLOC, true));
}
int asan_posix_memalign(void **memptr, uptr alignment, uptr size,
BufferedStackTrace *stack) {
if (UNLIKELY(!CheckPosixMemalignAlignment(alignment))) {
if (AllocatorMayReturnNull())
return errno_EINVAL;
ReportInvalidPosixMemalignAlignment(alignment, stack);
}
void *ptr = instance.Allocate(size, alignment, stack, FROM_MALLOC, true);
if (UNLIKELY(!ptr))
// OOM error is already taken care of by Allocate.
return errno_ENOMEM;
CHECK(IsAligned((uptr)ptr, alignment));
*memptr = ptr;
return 0;
}
uptr asan_malloc_usable_size(const void *ptr, uptr pc, uptr bp) {
if (!ptr) return 0;
uptr usable_size = instance.AllocationSize(reinterpret_cast<uptr>(ptr));
if (flags()->check_malloc_usable_size && (usable_size == 0)) {
GET_STACK_TRACE_FATAL(pc, bp);
ReportMallocUsableSizeNotOwned((uptr)ptr, &stack);
}
return usable_size;
}
uptr asan_mz_size(const void *ptr) {
return instance.AllocationSize(reinterpret_cast<uptr>(ptr));
}
void asan_mz_force_lock() NO_THREAD_SAFETY_ANALYSIS { instance.ForceLock(); }
void asan_mz_force_unlock() NO_THREAD_SAFETY_ANALYSIS {
instance.ForceUnlock();
}
void AsanSoftRssLimitExceededCallback(bool limit_exceeded) {
instance.SetRssLimitExceeded(limit_exceeded);
}
} // namespace __asan
// --- Implementation of LSan-specific functions --- {{{1
namespace __lsan {
void LockAllocator() {
__asan::get_allocator().ForceLock();
}
void UnlockAllocator() {
__asan::get_allocator().ForceUnlock();
}
void GetAllocatorGlobalRange(uptr *begin, uptr *end) {
*begin = (uptr)&__asan::get_allocator();
*end = *begin + sizeof(__asan::get_allocator());
}
uptr PointsIntoChunk(void *p) {
uptr addr = reinterpret_cast<uptr>(p);
__asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddrFastLocked(addr);
if (!m || atomic_load(&m->chunk_state, memory_order_acquire) !=
__asan::CHUNK_ALLOCATED)
return 0;
uptr chunk = m->Beg();
if (m->AddrIsInside(addr))
return chunk;
if (IsSpecialCaseOfOperatorNew0(chunk, m->UsedSize(), addr))
return chunk;
return 0;
}
uptr GetUserBegin(uptr chunk) {
__asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddrFastLocked(chunk);
return m ? m->Beg() : 0;
}
LsanMetadata::LsanMetadata(uptr chunk) {
metadata_ = chunk ? reinterpret_cast<void *>(chunk - __asan::kChunkHeaderSize)
: nullptr;
}
bool LsanMetadata::allocated() const {
if (!metadata_)
return false;
__asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
return atomic_load(&m->chunk_state, memory_order_relaxed) ==
__asan::CHUNK_ALLOCATED;
}
ChunkTag LsanMetadata::tag() const {
__asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
return static_cast<ChunkTag>(m->lsan_tag);
}
void LsanMetadata::set_tag(ChunkTag value) {
__asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
m->lsan_tag = value;
}
uptr LsanMetadata::requested_size() const {
__asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
return m->UsedSize();
}
u32 LsanMetadata::stack_trace_id() const {
__asan::AsanChunk *m = reinterpret_cast<__asan::AsanChunk *>(metadata_);
u32 tid = 0;
u32 stack = 0;
m->GetAllocContext(tid, stack);
return stack;
}
void ForEachChunk(ForEachChunkCallback callback, void *arg) {
__asan::get_allocator().ForEachChunk(callback, arg);
}
IgnoreObjectResult IgnoreObjectLocked(const void *p) {
uptr addr = reinterpret_cast<uptr>(p);
__asan::AsanChunk *m = __asan::instance.GetAsanChunkByAddr(addr);
if (!m ||
(atomic_load(&m->chunk_state, memory_order_acquire) !=
__asan::CHUNK_ALLOCATED) ||
!m->AddrIsInside(addr)) {
return kIgnoreObjectInvalid;
}
if (m->lsan_tag == kIgnored)
return kIgnoreObjectAlreadyIgnored;
m->lsan_tag = __lsan::kIgnored;
return kIgnoreObjectSuccess;
}
void GetAdditionalThreadContextPtrs(ThreadContextBase *tctx, void *ptrs) {
// Look for the arg pointer of threads that have been created or are running.
// This is necessary to prevent false positive leaks due to the AsanThread
// holding the only live reference to a heap object. This can happen because
// the `pthread_create()` interceptor doesn't wait for the child thread to
// start before returning and thus loosing the the only live reference to the
// heap object on the stack.
__asan::AsanThreadContext *atctx =
reinterpret_cast<__asan::AsanThreadContext *>(tctx);
__asan::AsanThread *asan_thread = atctx->thread;
// Note ThreadStatusRunning is required because there is a small window where
// the thread status switches to `ThreadStatusRunning` but the `arg` pointer
// still isn't on the stack yet.
if (atctx->status != ThreadStatusCreated &&
atctx->status != ThreadStatusRunning)
return;
uptr thread_arg = reinterpret_cast<uptr>(asan_thread->get_arg());
if (!thread_arg)
return;
auto ptrsVec = reinterpret_cast<InternalMmapVector<uptr> *>(ptrs);
ptrsVec->push_back(thread_arg);
}
} // namespace __lsan
// ---------------------- Interface ---------------- {{{1
using namespace __asan;
// ASan allocator doesn't reserve extra bytes, so normally we would
// just return "size". We don't want to expose our redzone sizes, etc here.
uptr __sanitizer_get_estimated_allocated_size(uptr size) {
return size;
}
int __sanitizer_get_ownership(const void *p) {
uptr ptr = reinterpret_cast<uptr>(p);
return instance.AllocationSize(ptr) > 0;
}
uptr __sanitizer_get_allocated_size(const void *p) {
if (!p) return 0;
uptr ptr = reinterpret_cast<uptr>(p);
uptr allocated_size = instance.AllocationSize(ptr);
// Die if p is not malloced or if it is already freed.
if (allocated_size == 0) {
GET_STACK_TRACE_FATAL_HERE;
ReportSanitizerGetAllocatedSizeNotOwned(ptr, &stack);
}
return allocated_size;
}
void __sanitizer_purge_allocator() {
GET_STACK_TRACE_MALLOC;
instance.Purge(&stack);
}
int __asan_update_allocation_context(void* addr) {
GET_STACK_TRACE_MALLOC;
return instance.UpdateAllocationStack((uptr)addr, &stack);
}
#if !SANITIZER_SUPPORTS_WEAK_HOOKS
// Provide default (no-op) implementation of malloc hooks.
SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_malloc_hook,
void *ptr, uptr size) {
(void)ptr;
(void)size;
}
SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_free_hook, void *ptr) {
(void)ptr;
}
#endif
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