forked from OSchip/llvm-project
745 lines
28 KiB
C++
745 lines
28 KiB
C++
//===-- scudo_allocator.cpp -------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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///
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/// Scudo Hardened Allocator implementation.
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/// It uses the sanitizer_common allocator as a base and aims at mitigating
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/// heap corruption vulnerabilities. It provides a checksum-guarded chunk
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/// header, a delayed free list, and additional sanity checks.
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///
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//===----------------------------------------------------------------------===//
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#include "scudo_allocator.h"
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#include "scudo_crc32.h"
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#include "scudo_flags.h"
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#include "scudo_tsd.h"
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#include "scudo_utils.h"
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#include "sanitizer_common/sanitizer_allocator_checks.h"
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#include "sanitizer_common/sanitizer_allocator_interface.h"
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#include "sanitizer_common/sanitizer_quarantine.h"
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#include <errno.h>
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#include <string.h>
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namespace __scudo {
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// Global static cookie, initialized at start-up.
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static u32 Cookie;
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// We default to software CRC32 if the alternatives are not supported, either
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// at compilation or at runtime.
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static atomic_uint8_t HashAlgorithm = { CRC32Software };
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INLINE u32 computeCRC32(u32 Crc, uptr Value, uptr *Array, uptr ArraySize) {
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// If the hardware CRC32 feature is defined here, it was enabled everywhere,
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// as opposed to only for scudo_crc32.cpp. This means that other hardware
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// specific instructions were likely emitted at other places, and as a
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// result there is no reason to not use it here.
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#if defined(__SSE4_2__) || defined(__ARM_FEATURE_CRC32)
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Crc = CRC32_INTRINSIC(Crc, Value);
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for (uptr i = 0; i < ArraySize; i++)
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Crc = CRC32_INTRINSIC(Crc, Array[i]);
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return Crc;
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#else
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if (atomic_load_relaxed(&HashAlgorithm) == CRC32Hardware) {
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Crc = computeHardwareCRC32(Crc, Value);
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for (uptr i = 0; i < ArraySize; i++)
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Crc = computeHardwareCRC32(Crc, Array[i]);
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return Crc;
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}
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Crc = computeSoftwareCRC32(Crc, Value);
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for (uptr i = 0; i < ArraySize; i++)
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Crc = computeSoftwareCRC32(Crc, Array[i]);
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return Crc;
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#endif // defined(__SSE4_2__) || defined(__ARM_FEATURE_CRC32)
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}
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static ScudoBackendAllocator &getBackendAllocator();
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namespace Chunk {
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// We can't use the offset member of the chunk itself, as we would double
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// fetch it without any warranty that it wouldn't have been tampered. To
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// prevent this, we work with a local copy of the header.
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static INLINE void *getBackendPtr(const void *Ptr, UnpackedHeader *Header) {
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return reinterpret_cast<void *>(reinterpret_cast<uptr>(Ptr) -
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AlignedChunkHeaderSize -
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(Header->Offset << MinAlignmentLog));
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}
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static INLINE AtomicPackedHeader *getAtomicHeader(void *Ptr) {
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return reinterpret_cast<AtomicPackedHeader *>(reinterpret_cast<uptr>(Ptr) -
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AlignedChunkHeaderSize);
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}
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static INLINE
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const AtomicPackedHeader *getConstAtomicHeader(const void *Ptr) {
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return reinterpret_cast<const AtomicPackedHeader *>(
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reinterpret_cast<uptr>(Ptr) - AlignedChunkHeaderSize);
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}
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static INLINE bool isAligned(const void *Ptr) {
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return IsAligned(reinterpret_cast<uptr>(Ptr), MinAlignment);
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}
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// Returns the usable size for a chunk, meaning the amount of bytes from the
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// beginning of the user data to the end of the backend allocated chunk.
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static INLINE uptr getUsableSize(const void *Ptr, UnpackedHeader *Header) {
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const uptr Size = getBackendAllocator().getActuallyAllocatedSize(
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getBackendPtr(Ptr, Header), Header->ClassId);
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if (Size == 0)
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return 0;
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return Size - AlignedChunkHeaderSize - (Header->Offset << MinAlignmentLog);
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}
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// Compute the checksum of the chunk pointer and its header.
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static INLINE u16 computeChecksum(const void *Ptr, UnpackedHeader *Header) {
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UnpackedHeader ZeroChecksumHeader = *Header;
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ZeroChecksumHeader.Checksum = 0;
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uptr HeaderHolder[sizeof(UnpackedHeader) / sizeof(uptr)];
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memcpy(&HeaderHolder, &ZeroChecksumHeader, sizeof(HeaderHolder));
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const u32 Crc = computeCRC32(Cookie, reinterpret_cast<uptr>(Ptr),
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HeaderHolder, ARRAY_SIZE(HeaderHolder));
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return static_cast<u16>(Crc);
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}
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// Checks the validity of a chunk by verifying its checksum. It doesn't
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// incur termination in the event of an invalid chunk.
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static INLINE bool isValid(const void *Ptr) {
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PackedHeader NewPackedHeader =
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atomic_load_relaxed(getConstAtomicHeader(Ptr));
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UnpackedHeader NewUnpackedHeader =
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bit_cast<UnpackedHeader>(NewPackedHeader);
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return (NewUnpackedHeader.Checksum ==
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computeChecksum(Ptr, &NewUnpackedHeader));
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}
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// Nulls out a chunk header. When returning the chunk to the backend, there
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// is no need to store a valid ChunkAvailable header, as this would be
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// computationally expensive. Zeroing out serves the same purpose by making
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// the header invalid. In the extremely rare event where 0 would be a valid
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// checksum for the chunk, the state of the chunk is ChunkAvailable anyway.
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COMPILER_CHECK(ChunkAvailable == 0);
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static INLINE void eraseHeader(void *Ptr) {
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const PackedHeader NullPackedHeader = 0;
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atomic_store_relaxed(getAtomicHeader(Ptr), NullPackedHeader);
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}
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// Loads and unpacks the header, verifying the checksum in the process.
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static INLINE
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void loadHeader(const void *Ptr, UnpackedHeader *NewUnpackedHeader) {
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PackedHeader NewPackedHeader =
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atomic_load_relaxed(getConstAtomicHeader(Ptr));
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*NewUnpackedHeader = bit_cast<UnpackedHeader>(NewPackedHeader);
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if (UNLIKELY(NewUnpackedHeader->Checksum !=
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computeChecksum(Ptr, NewUnpackedHeader))) {
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dieWithMessage("ERROR: corrupted chunk header at address %p\n", Ptr);
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}
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}
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// Packs and stores the header, computing the checksum in the process.
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static INLINE void storeHeader(void *Ptr, UnpackedHeader *NewUnpackedHeader) {
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NewUnpackedHeader->Checksum = computeChecksum(Ptr, NewUnpackedHeader);
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PackedHeader NewPackedHeader = bit_cast<PackedHeader>(*NewUnpackedHeader);
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atomic_store_relaxed(getAtomicHeader(Ptr), NewPackedHeader);
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}
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// Packs and stores the header, computing the checksum in the process. We
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// compare the current header with the expected provided one to ensure that
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// we are not being raced by a corruption occurring in another thread.
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static INLINE void compareExchangeHeader(void *Ptr,
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UnpackedHeader *NewUnpackedHeader,
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UnpackedHeader *OldUnpackedHeader) {
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NewUnpackedHeader->Checksum = computeChecksum(Ptr, NewUnpackedHeader);
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PackedHeader NewPackedHeader = bit_cast<PackedHeader>(*NewUnpackedHeader);
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PackedHeader OldPackedHeader = bit_cast<PackedHeader>(*OldUnpackedHeader);
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if (UNLIKELY(!atomic_compare_exchange_strong(
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getAtomicHeader(Ptr), &OldPackedHeader, NewPackedHeader,
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memory_order_relaxed))) {
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dieWithMessage("ERROR: race on chunk header at address %p\n", Ptr);
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}
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}
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} // namespace Chunk
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struct QuarantineCallback {
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explicit QuarantineCallback(AllocatorCache *Cache)
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: Cache_(Cache) {}
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// Chunk recycling function, returns a quarantined chunk to the backend,
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// first making sure it hasn't been tampered with.
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void Recycle(void *Ptr) {
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UnpackedHeader Header;
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Chunk::loadHeader(Ptr, &Header);
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if (UNLIKELY(Header.State != ChunkQuarantine)) {
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dieWithMessage("ERROR: invalid chunk state when recycling address %p\n",
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Ptr);
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}
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Chunk::eraseHeader(Ptr);
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void *BackendPtr = Chunk::getBackendPtr(Ptr, &Header);
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if (Header.ClassId)
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getBackendAllocator().deallocatePrimary(Cache_, BackendPtr,
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Header.ClassId);
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else
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getBackendAllocator().deallocateSecondary(BackendPtr);
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}
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// Internal quarantine allocation and deallocation functions. We first check
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// that the batches are indeed serviced by the Primary.
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// TODO(kostyak): figure out the best way to protect the batches.
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void *Allocate(uptr Size) {
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return getBackendAllocator().allocatePrimary(Cache_, BatchClassId);
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}
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void Deallocate(void *Ptr) {
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getBackendAllocator().deallocatePrimary(Cache_, Ptr, BatchClassId);
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}
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AllocatorCache *Cache_;
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COMPILER_CHECK(sizeof(QuarantineBatch) < SizeClassMap::kMaxSize);
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const uptr BatchClassId = SizeClassMap::ClassID(sizeof(QuarantineBatch));
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};
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typedef Quarantine<QuarantineCallback, void> ScudoQuarantine;
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typedef ScudoQuarantine::Cache ScudoQuarantineCache;
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COMPILER_CHECK(sizeof(ScudoQuarantineCache) <=
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sizeof(ScudoTSD::QuarantineCachePlaceHolder));
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ScudoQuarantineCache *getQuarantineCache(ScudoTSD *TSD) {
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return reinterpret_cast<ScudoQuarantineCache *>(
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TSD->QuarantineCachePlaceHolder);
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}
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struct ScudoAllocator {
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static const uptr MaxAllowedMallocSize =
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FIRST_32_SECOND_64(2UL << 30, 1ULL << 40);
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typedef ReturnNullOrDieOnFailure FailureHandler;
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ScudoBackendAllocator BackendAllocator;
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ScudoQuarantine AllocatorQuarantine;
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u32 QuarantineChunksUpToSize;
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bool DeallocationTypeMismatch;
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bool ZeroContents;
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bool DeleteSizeMismatch;
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bool CheckRssLimit;
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uptr HardRssLimitMb;
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uptr SoftRssLimitMb;
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atomic_uint8_t RssLimitExceeded;
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atomic_uint64_t RssLastCheckedAtNS;
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explicit ScudoAllocator(LinkerInitialized)
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: AllocatorQuarantine(LINKER_INITIALIZED) {}
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void performSanityChecks() {
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// Verify that the header offset field can hold the maximum offset. In the
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// case of the Secondary allocator, it takes care of alignment and the
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// offset will always be 0. In the case of the Primary, the worst case
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// scenario happens in the last size class, when the backend allocation
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// would already be aligned on the requested alignment, which would happen
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// to be the maximum alignment that would fit in that size class. As a
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// result, the maximum offset will be at most the maximum alignment for the
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// last size class minus the header size, in multiples of MinAlignment.
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UnpackedHeader Header = {};
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const uptr MaxPrimaryAlignment =
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1 << MostSignificantSetBitIndex(SizeClassMap::kMaxSize - MinAlignment);
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const uptr MaxOffset =
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(MaxPrimaryAlignment - AlignedChunkHeaderSize) >> MinAlignmentLog;
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Header.Offset = MaxOffset;
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if (Header.Offset != MaxOffset) {
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dieWithMessage("ERROR: the maximum possible offset doesn't fit in the "
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"header\n");
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}
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// Verify that we can fit the maximum size or amount of unused bytes in the
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// header. Given that the Secondary fits the allocation to a page, the worst
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// case scenario happens in the Primary. It will depend on the second to
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// last and last class sizes, as well as the dynamic base for the Primary.
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// The following is an over-approximation that works for our needs.
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const uptr MaxSizeOrUnusedBytes = SizeClassMap::kMaxSize - 1;
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Header.SizeOrUnusedBytes = MaxSizeOrUnusedBytes;
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if (Header.SizeOrUnusedBytes != MaxSizeOrUnusedBytes) {
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dieWithMessage("ERROR: the maximum possible unused bytes doesn't fit in "
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"the header\n");
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}
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const uptr LargestClassId = SizeClassMap::kLargestClassID;
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Header.ClassId = LargestClassId;
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if (Header.ClassId != LargestClassId) {
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dieWithMessage("ERROR: the largest class ID doesn't fit in the header\n");
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}
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}
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void init() {
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SanitizerToolName = "Scudo";
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initFlags();
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performSanityChecks();
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// Check if hardware CRC32 is supported in the binary and by the platform,
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// if so, opt for the CRC32 hardware version of the checksum.
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if (&computeHardwareCRC32 && hasHardwareCRC32())
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atomic_store_relaxed(&HashAlgorithm, CRC32Hardware);
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SetAllocatorMayReturnNull(common_flags()->allocator_may_return_null);
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BackendAllocator.init(common_flags()->allocator_release_to_os_interval_ms);
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HardRssLimitMb = common_flags()->hard_rss_limit_mb;
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SoftRssLimitMb = common_flags()->soft_rss_limit_mb;
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AllocatorQuarantine.Init(
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static_cast<uptr>(getFlags()->QuarantineSizeKb) << 10,
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static_cast<uptr>(getFlags()->ThreadLocalQuarantineSizeKb) << 10);
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QuarantineChunksUpToSize = getFlags()->QuarantineChunksUpToSize;
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DeallocationTypeMismatch = getFlags()->DeallocationTypeMismatch;
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DeleteSizeMismatch = getFlags()->DeleteSizeMismatch;
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ZeroContents = getFlags()->ZeroContents;
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if (UNLIKELY(!GetRandom(reinterpret_cast<void *>(&Cookie), sizeof(Cookie),
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/*blocking=*/false))) {
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Cookie = static_cast<u32>((NanoTime() >> 12) ^
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(reinterpret_cast<uptr>(this) >> 4));
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}
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CheckRssLimit = HardRssLimitMb || SoftRssLimitMb;
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if (CheckRssLimit)
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atomic_store_relaxed(&RssLastCheckedAtNS, MonotonicNanoTime());
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}
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// Helper function that checks for a valid Scudo chunk. nullptr isn't.
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bool isValidPointer(const void *Ptr) {
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initThreadMaybe();
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if (UNLIKELY(!Ptr))
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return false;
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if (!Chunk::isAligned(Ptr))
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return false;
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return Chunk::isValid(Ptr);
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}
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// Opportunistic RSS limit check. This will update the RSS limit status, if
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// it can, every 100ms, otherwise it will just return the current one.
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bool isRssLimitExceeded() {
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u64 LastCheck = atomic_load_relaxed(&RssLastCheckedAtNS);
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const u64 CurrentCheck = MonotonicNanoTime();
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if (LIKELY(CurrentCheck < LastCheck + (100ULL * 1000000ULL)))
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return atomic_load_relaxed(&RssLimitExceeded);
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if (!atomic_compare_exchange_weak(&RssLastCheckedAtNS, &LastCheck,
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CurrentCheck, memory_order_relaxed))
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return atomic_load_relaxed(&RssLimitExceeded);
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// TODO(kostyak): We currently use sanitizer_common's GetRSS which reads the
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// RSS from /proc/self/statm by default. We might want to
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// call getrusage directly, even if it's less accurate.
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const uptr CurrentRssMb = GetRSS() >> 20;
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if (HardRssLimitMb && HardRssLimitMb < CurrentRssMb) {
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Report("%s: hard RSS limit exhausted (%zdMb vs %zdMb)\n",
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SanitizerToolName, HardRssLimitMb, CurrentRssMb);
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DumpProcessMap();
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Die();
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}
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if (SoftRssLimitMb) {
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if (atomic_load_relaxed(&RssLimitExceeded)) {
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if (CurrentRssMb <= SoftRssLimitMb)
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atomic_store_relaxed(&RssLimitExceeded, false);
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} else {
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if (CurrentRssMb > SoftRssLimitMb) {
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atomic_store_relaxed(&RssLimitExceeded, true);
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Report("%s: soft RSS limit exhausted (%zdMb vs %zdMb)\n",
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SanitizerToolName, SoftRssLimitMb, CurrentRssMb);
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}
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}
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}
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return atomic_load_relaxed(&RssLimitExceeded);
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}
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// Allocates a chunk.
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void *allocate(uptr Size, uptr Alignment, AllocType Type,
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bool ForceZeroContents = false) {
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initThreadMaybe();
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if (UNLIKELY(Alignment > MaxAlignment))
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return FailureHandler::OnBadRequest();
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if (UNLIKELY(Alignment < MinAlignment))
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Alignment = MinAlignment;
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if (UNLIKELY(Size >= MaxAllowedMallocSize))
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return FailureHandler::OnBadRequest();
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if (UNLIKELY(Size == 0))
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Size = 1;
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uptr NeededSize = RoundUpTo(Size, MinAlignment) + AlignedChunkHeaderSize;
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uptr AlignedSize = (Alignment > MinAlignment) ?
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NeededSize + (Alignment - AlignedChunkHeaderSize) : NeededSize;
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if (UNLIKELY(AlignedSize >= MaxAllowedMallocSize))
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return FailureHandler::OnBadRequest();
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if (CheckRssLimit && UNLIKELY(isRssLimitExceeded()))
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return FailureHandler::OnOOM();
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// Primary and Secondary backed allocations have a different treatment. We
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// deal with alignment requirements of Primary serviced allocations here,
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// but the Secondary will take care of its own alignment needs.
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void *BackendPtr;
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uptr BackendSize;
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u8 ClassId;
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if (PrimaryAllocator::CanAllocate(AlignedSize, MinAlignment)) {
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BackendSize = AlignedSize;
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ClassId = SizeClassMap::ClassID(BackendSize);
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ScudoTSD *TSD = getTSDAndLock();
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BackendPtr = BackendAllocator.allocatePrimary(&TSD->Cache, ClassId);
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TSD->unlock();
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} else {
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BackendSize = NeededSize;
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ClassId = 0;
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BackendPtr = BackendAllocator.allocateSecondary(BackendSize, Alignment);
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}
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if (UNLIKELY(!BackendPtr))
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return FailureHandler::OnOOM();
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// If requested, we will zero out the entire contents of the returned chunk.
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if ((ForceZeroContents || ZeroContents) && ClassId)
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memset(BackendPtr, 0,
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BackendAllocator.getActuallyAllocatedSize(BackendPtr, ClassId));
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UnpackedHeader Header = {};
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uptr UserPtr = reinterpret_cast<uptr>(BackendPtr) + AlignedChunkHeaderSize;
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if (UNLIKELY(!IsAligned(UserPtr, Alignment))) {
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// Since the Secondary takes care of alignment, a non-aligned pointer
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// means it is from the Primary. It is also the only case where the offset
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// field of the header would be non-zero.
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DCHECK(ClassId);
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const uptr AlignedUserPtr = RoundUpTo(UserPtr, Alignment);
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Header.Offset = (AlignedUserPtr - UserPtr) >> MinAlignmentLog;
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UserPtr = AlignedUserPtr;
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}
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CHECK_LE(UserPtr + Size, reinterpret_cast<uptr>(BackendPtr) + BackendSize);
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Header.State = ChunkAllocated;
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Header.AllocType = Type;
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if (ClassId) {
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Header.ClassId = ClassId;
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Header.SizeOrUnusedBytes = Size;
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} else {
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// The secondary fits the allocations to a page, so the amount of unused
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// bytes is the difference between the end of the user allocation and the
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// next page boundary.
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const uptr PageSize = GetPageSizeCached();
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const uptr TrailingBytes = (UserPtr + Size) & (PageSize - 1);
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if (TrailingBytes)
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Header.SizeOrUnusedBytes = PageSize - TrailingBytes;
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}
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void *Ptr = reinterpret_cast<void *>(UserPtr);
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Chunk::storeHeader(Ptr, &Header);
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// if (&__sanitizer_malloc_hook) __sanitizer_malloc_hook(Ptr, Size);
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return Ptr;
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}
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// Place a chunk in the quarantine or directly deallocate it in the event of
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// a zero-sized quarantine, or if the size of the chunk is greater than the
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// quarantine chunk size threshold.
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void quarantineOrDeallocateChunk(void *Ptr, UnpackedHeader *Header,
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uptr Size) {
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const bool BypassQuarantine = (AllocatorQuarantine.GetCacheSize() == 0) ||
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(Size > QuarantineChunksUpToSize);
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if (BypassQuarantine) {
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Chunk::eraseHeader(Ptr);
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|
void *BackendPtr = Chunk::getBackendPtr(Ptr, Header);
|
|
if (Header->ClassId) {
|
|
ScudoTSD *TSD = getTSDAndLock();
|
|
getBackendAllocator().deallocatePrimary(&TSD->Cache, BackendPtr,
|
|
Header->ClassId);
|
|
TSD->unlock();
|
|
} else {
|
|
getBackendAllocator().deallocateSecondary(BackendPtr);
|
|
}
|
|
} else {
|
|
// If a small memory amount was allocated with a larger alignment, we want
|
|
// to take that into account. Otherwise the Quarantine would be filled
|
|
// with tiny chunks, taking a lot of VA memory. This is an approximation
|
|
// of the usable size, that allows us to not call
|
|
// GetActuallyAllocatedSize.
|
|
uptr EstimatedSize = Size + (Header->Offset << MinAlignmentLog);
|
|
UnpackedHeader NewHeader = *Header;
|
|
NewHeader.State = ChunkQuarantine;
|
|
Chunk::compareExchangeHeader(Ptr, &NewHeader, Header);
|
|
ScudoTSD *TSD = getTSDAndLock();
|
|
AllocatorQuarantine.Put(getQuarantineCache(TSD),
|
|
QuarantineCallback(&TSD->Cache), Ptr,
|
|
EstimatedSize);
|
|
TSD->unlock();
|
|
}
|
|
}
|
|
|
|
// Deallocates a Chunk, which means either adding it to the quarantine or
|
|
// directly returning it to the backend if criteria are met.
|
|
void deallocate(void *Ptr, uptr DeleteSize, AllocType Type) {
|
|
// For a deallocation, we only ensure minimal initialization, meaning thread
|
|
// local data will be left uninitialized for now (when using ELF TLS). The
|
|
// fallback cache will be used instead. This is a workaround for a situation
|
|
// where the only heap operation performed in a thread would be a free past
|
|
// the TLS destructors, ending up in initialized thread specific data never
|
|
// being destroyed properly. Any other heap operation will do a full init.
|
|
initThreadMaybe(/*MinimalInit=*/true);
|
|
// if (&__sanitizer_free_hook) __sanitizer_free_hook(Ptr);
|
|
if (UNLIKELY(!Ptr))
|
|
return;
|
|
if (UNLIKELY(!Chunk::isAligned(Ptr))) {
|
|
dieWithMessage("ERROR: attempted to deallocate a chunk not properly "
|
|
"aligned at address %p\n", Ptr);
|
|
}
|
|
UnpackedHeader Header;
|
|
Chunk::loadHeader(Ptr, &Header);
|
|
if (UNLIKELY(Header.State != ChunkAllocated)) {
|
|
dieWithMessage("ERROR: invalid chunk state when deallocating address "
|
|
"%p\n", Ptr);
|
|
}
|
|
if (DeallocationTypeMismatch) {
|
|
// The deallocation type has to match the allocation one.
|
|
if (Header.AllocType != Type) {
|
|
// With the exception of memalign'd Chunks, that can be still be free'd.
|
|
if (Header.AllocType != FromMemalign || Type != FromMalloc) {
|
|
dieWithMessage("ERROR: allocation type mismatch when deallocating "
|
|
"address %p\n", Ptr);
|
|
}
|
|
}
|
|
}
|
|
uptr Size = Header.ClassId ? Header.SizeOrUnusedBytes :
|
|
Chunk::getUsableSize(Ptr, &Header) - Header.SizeOrUnusedBytes;
|
|
if (DeleteSizeMismatch) {
|
|
if (DeleteSize && DeleteSize != Size) {
|
|
dieWithMessage("ERROR: invalid sized delete on chunk at address %p\n",
|
|
Ptr);
|
|
}
|
|
}
|
|
quarantineOrDeallocateChunk(Ptr, &Header, Size);
|
|
}
|
|
|
|
// Reallocates a chunk. We can save on a new allocation if the new requested
|
|
// size still fits in the chunk.
|
|
void *reallocate(void *OldPtr, uptr NewSize) {
|
|
initThreadMaybe();
|
|
if (UNLIKELY(!Chunk::isAligned(OldPtr))) {
|
|
dieWithMessage("ERROR: attempted to reallocate a chunk not properly "
|
|
"aligned at address %p\n", OldPtr);
|
|
}
|
|
UnpackedHeader OldHeader;
|
|
Chunk::loadHeader(OldPtr, &OldHeader);
|
|
if (UNLIKELY(OldHeader.State != ChunkAllocated)) {
|
|
dieWithMessage("ERROR: invalid chunk state when reallocating address "
|
|
"%p\n", OldPtr);
|
|
}
|
|
if (DeallocationTypeMismatch) {
|
|
if (UNLIKELY(OldHeader.AllocType != FromMalloc)) {
|
|
dieWithMessage("ERROR: allocation type mismatch when reallocating "
|
|
"address %p\n", OldPtr);
|
|
}
|
|
}
|
|
const uptr UsableSize = Chunk::getUsableSize(OldPtr, &OldHeader);
|
|
// The new size still fits in the current chunk, and the size difference
|
|
// is reasonable.
|
|
if (NewSize <= UsableSize &&
|
|
(UsableSize - NewSize) < (SizeClassMap::kMaxSize / 2)) {
|
|
UnpackedHeader NewHeader = OldHeader;
|
|
NewHeader.SizeOrUnusedBytes =
|
|
OldHeader.ClassId ? NewSize : UsableSize - NewSize;
|
|
Chunk::compareExchangeHeader(OldPtr, &NewHeader, &OldHeader);
|
|
return OldPtr;
|
|
}
|
|
// Otherwise, we have to allocate a new chunk and copy the contents of the
|
|
// old one.
|
|
void *NewPtr = allocate(NewSize, MinAlignment, FromMalloc);
|
|
if (NewPtr) {
|
|
uptr OldSize = OldHeader.ClassId ? OldHeader.SizeOrUnusedBytes :
|
|
UsableSize - OldHeader.SizeOrUnusedBytes;
|
|
memcpy(NewPtr, OldPtr, Min(NewSize, UsableSize));
|
|
quarantineOrDeallocateChunk(OldPtr, &OldHeader, OldSize);
|
|
}
|
|
return NewPtr;
|
|
}
|
|
|
|
// Helper function that returns the actual usable size of a chunk.
|
|
uptr getUsableSize(const void *Ptr) {
|
|
initThreadMaybe();
|
|
if (UNLIKELY(!Ptr))
|
|
return 0;
|
|
UnpackedHeader Header;
|
|
Chunk::loadHeader(Ptr, &Header);
|
|
// Getting the usable size of a chunk only makes sense if it's allocated.
|
|
if (UNLIKELY(Header.State != ChunkAllocated)) {
|
|
dieWithMessage("ERROR: invalid chunk state when sizing address %p\n",
|
|
Ptr);
|
|
}
|
|
return Chunk::getUsableSize(Ptr, &Header);
|
|
}
|
|
|
|
void *calloc(uptr NMemB, uptr Size) {
|
|
initThreadMaybe();
|
|
if (UNLIKELY(CheckForCallocOverflow(NMemB, Size)))
|
|
return FailureHandler::OnBadRequest();
|
|
return allocate(NMemB * Size, MinAlignment, FromMalloc, true);
|
|
}
|
|
|
|
void commitBack(ScudoTSD *TSD) {
|
|
AllocatorQuarantine.Drain(getQuarantineCache(TSD),
|
|
QuarantineCallback(&TSD->Cache));
|
|
BackendAllocator.destroyCache(&TSD->Cache);
|
|
}
|
|
|
|
uptr getStats(AllocatorStat StatType) {
|
|
initThreadMaybe();
|
|
uptr stats[AllocatorStatCount];
|
|
BackendAllocator.getStats(stats);
|
|
return stats[StatType];
|
|
}
|
|
|
|
void *handleBadRequest() {
|
|
initThreadMaybe();
|
|
return FailureHandler::OnBadRequest();
|
|
}
|
|
|
|
void setRssLimit(uptr LimitMb, bool HardLimit) {
|
|
if (HardLimit)
|
|
HardRssLimitMb = LimitMb;
|
|
else
|
|
SoftRssLimitMb = LimitMb;
|
|
CheckRssLimit = HardRssLimitMb || SoftRssLimitMb;
|
|
}
|
|
};
|
|
|
|
static ScudoAllocator Instance(LINKER_INITIALIZED);
|
|
|
|
static ScudoBackendAllocator &getBackendAllocator() {
|
|
return Instance.BackendAllocator;
|
|
}
|
|
|
|
void initScudo() {
|
|
Instance.init();
|
|
}
|
|
|
|
void ScudoTSD::init(bool Shared) {
|
|
UnlockRequired = Shared;
|
|
getBackendAllocator().initCache(&Cache);
|
|
memset(QuarantineCachePlaceHolder, 0, sizeof(QuarantineCachePlaceHolder));
|
|
}
|
|
|
|
void ScudoTSD::commitBack() {
|
|
Instance.commitBack(this);
|
|
}
|
|
|
|
void *scudoMalloc(uptr Size, AllocType Type) {
|
|
return SetErrnoOnNull(Instance.allocate(Size, MinAlignment, Type));
|
|
}
|
|
|
|
void scudoFree(void *Ptr, AllocType Type) {
|
|
Instance.deallocate(Ptr, 0, Type);
|
|
}
|
|
|
|
void scudoSizedFree(void *Ptr, uptr Size, AllocType Type) {
|
|
Instance.deallocate(Ptr, Size, Type);
|
|
}
|
|
|
|
void *scudoRealloc(void *Ptr, uptr Size) {
|
|
if (!Ptr)
|
|
return SetErrnoOnNull(Instance.allocate(Size, MinAlignment, FromMalloc));
|
|
if (Size == 0) {
|
|
Instance.deallocate(Ptr, 0, FromMalloc);
|
|
return nullptr;
|
|
}
|
|
return SetErrnoOnNull(Instance.reallocate(Ptr, Size));
|
|
}
|
|
|
|
void *scudoCalloc(uptr NMemB, uptr Size) {
|
|
return SetErrnoOnNull(Instance.calloc(NMemB, Size));
|
|
}
|
|
|
|
void *scudoValloc(uptr Size) {
|
|
return SetErrnoOnNull(
|
|
Instance.allocate(Size, GetPageSizeCached(), FromMemalign));
|
|
}
|
|
|
|
void *scudoPvalloc(uptr Size) {
|
|
uptr PageSize = GetPageSizeCached();
|
|
if (UNLIKELY(CheckForPvallocOverflow(Size, PageSize))) {
|
|
errno = ENOMEM;
|
|
return Instance.handleBadRequest();
|
|
}
|
|
// pvalloc(0) should allocate one page.
|
|
Size = Size ? RoundUpTo(Size, PageSize) : PageSize;
|
|
return SetErrnoOnNull(Instance.allocate(Size, PageSize, FromMemalign));
|
|
}
|
|
|
|
void *scudoMemalign(uptr Alignment, uptr Size) {
|
|
if (UNLIKELY(!IsPowerOfTwo(Alignment))) {
|
|
errno = EINVAL;
|
|
return Instance.handleBadRequest();
|
|
}
|
|
return SetErrnoOnNull(Instance.allocate(Size, Alignment, FromMemalign));
|
|
}
|
|
|
|
int scudoPosixMemalign(void **MemPtr, uptr Alignment, uptr Size) {
|
|
if (UNLIKELY(!CheckPosixMemalignAlignment(Alignment))) {
|
|
Instance.handleBadRequest();
|
|
return EINVAL;
|
|
}
|
|
void *Ptr = Instance.allocate(Size, Alignment, FromMemalign);
|
|
if (UNLIKELY(!Ptr))
|
|
return ENOMEM;
|
|
*MemPtr = Ptr;
|
|
return 0;
|
|
}
|
|
|
|
void *scudoAlignedAlloc(uptr Alignment, uptr Size) {
|
|
if (UNLIKELY(!CheckAlignedAllocAlignmentAndSize(Alignment, Size))) {
|
|
errno = EINVAL;
|
|
return Instance.handleBadRequest();
|
|
}
|
|
return SetErrnoOnNull(Instance.allocate(Size, Alignment, FromMalloc));
|
|
}
|
|
|
|
uptr scudoMallocUsableSize(void *Ptr) {
|
|
return Instance.getUsableSize(Ptr);
|
|
}
|
|
|
|
} // namespace __scudo
|
|
|
|
using namespace __scudo;
|
|
|
|
// MallocExtension helper functions
|
|
|
|
uptr __sanitizer_get_current_allocated_bytes() {
|
|
return Instance.getStats(AllocatorStatAllocated);
|
|
}
|
|
|
|
uptr __sanitizer_get_heap_size() {
|
|
return Instance.getStats(AllocatorStatMapped);
|
|
}
|
|
|
|
uptr __sanitizer_get_free_bytes() {
|
|
return 1;
|
|
}
|
|
|
|
uptr __sanitizer_get_unmapped_bytes() {
|
|
return 1;
|
|
}
|
|
|
|
uptr __sanitizer_get_estimated_allocated_size(uptr size) {
|
|
return size;
|
|
}
|
|
|
|
int __sanitizer_get_ownership(const void *Ptr) {
|
|
return Instance.isValidPointer(Ptr);
|
|
}
|
|
|
|
uptr __sanitizer_get_allocated_size(const void *Ptr) {
|
|
return Instance.getUsableSize(Ptr);
|
|
}
|
|
|
|
// Interface functions
|
|
|
|
extern "C" {
|
|
void __scudo_set_rss_limit(unsigned long LimitMb, int HardLimit) { // NOLINT
|
|
if (!SCUDO_CAN_USE_PUBLIC_INTERFACE)
|
|
return;
|
|
Instance.setRssLimit(LimitMb, !!HardLimit);
|
|
}
|
|
} // extern "C"
|