| //===-- combined.h ----------------------------------------------*- C++ -*-===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef SCUDO_COMBINED_H_ |
| #define SCUDO_COMBINED_H_ |
| |
| #include "chunk.h" |
| #include "common.h" |
| #include "flags.h" |
| #include "flags_parser.h" |
| #include "interface.h" |
| #include "local_cache.h" |
| #include "memtag.h" |
| #include "quarantine.h" |
| #include "report.h" |
| #include "secondary.h" |
| #include "string_utils.h" |
| #include "tsd.h" |
| |
| #ifdef GWP_ASAN_HOOKS |
| #include "gwp_asan/guarded_pool_allocator.h" |
| #include "gwp_asan/optional/backtrace.h" |
| #include "gwp_asan/optional/segv_handler.h" |
| #endif // GWP_ASAN_HOOKS |
| |
| extern "C" inline void EmptyCallback() {} |
| |
| namespace scudo { |
| |
| template <class Params, void (*PostInitCallback)(void) = EmptyCallback> |
| class Allocator { |
| public: |
| using PrimaryT = typename Params::Primary; |
| using CacheT = typename PrimaryT::CacheT; |
| typedef Allocator<Params, PostInitCallback> ThisT; |
| typedef typename Params::template TSDRegistryT<ThisT> TSDRegistryT; |
| |
| void callPostInitCallback() { |
| static pthread_once_t OnceControl = PTHREAD_ONCE_INIT; |
| pthread_once(&OnceControl, PostInitCallback); |
| } |
| |
| struct QuarantineCallback { |
| explicit QuarantineCallback(ThisT &Instance, CacheT &LocalCache) |
| : Allocator(Instance), Cache(LocalCache) {} |
| |
| // Chunk recycling function, returns a quarantined chunk to the backend, |
| // first making sure it hasn't been tampered with. |
| void recycle(void *Ptr) { |
| Chunk::UnpackedHeader Header; |
| Chunk::loadHeader(Allocator.Cookie, Ptr, &Header); |
| if (UNLIKELY(Header.State != Chunk::State::Quarantined)) |
| reportInvalidChunkState(AllocatorAction::Recycling, Ptr); |
| |
| Chunk::UnpackedHeader NewHeader = Header; |
| NewHeader.State = Chunk::State::Available; |
| Chunk::compareExchangeHeader(Allocator.Cookie, Ptr, &NewHeader, &Header); |
| |
| void *BlockBegin = Allocator::getBlockBegin(Ptr, &NewHeader); |
| const uptr ClassId = NewHeader.ClassId; |
| if (LIKELY(ClassId)) |
| Cache.deallocate(ClassId, BlockBegin); |
| else |
| Allocator.Secondary.deallocate(BlockBegin); |
| } |
| |
| // We take a shortcut when allocating a quarantine batch by working with the |
| // appropriate class ID instead of using Size. The compiler should optimize |
| // the class ID computation and work with the associated cache directly. |
| void *allocate(UNUSED uptr Size) { |
| const uptr QuarantineClassId = SizeClassMap::getClassIdBySize( |
| sizeof(QuarantineBatch) + Chunk::getHeaderSize()); |
| void *Ptr = Cache.allocate(QuarantineClassId); |
| // Quarantine batch allocation failure is fatal. |
| if (UNLIKELY(!Ptr)) |
| reportOutOfMemory(SizeClassMap::getSizeByClassId(QuarantineClassId)); |
| |
| Ptr = reinterpret_cast<void *>(reinterpret_cast<uptr>(Ptr) + |
| Chunk::getHeaderSize()); |
| Chunk::UnpackedHeader Header = {}; |
| Header.ClassId = QuarantineClassId & Chunk::ClassIdMask; |
| Header.SizeOrUnusedBytes = sizeof(QuarantineBatch); |
| Header.State = Chunk::State::Allocated; |
| Chunk::storeHeader(Allocator.Cookie, Ptr, &Header); |
| |
| return Ptr; |
| } |
| |
| void deallocate(void *Ptr) { |
| const uptr QuarantineClassId = SizeClassMap::getClassIdBySize( |
| sizeof(QuarantineBatch) + Chunk::getHeaderSize()); |
| Chunk::UnpackedHeader Header; |
| Chunk::loadHeader(Allocator.Cookie, Ptr, &Header); |
| |
| if (UNLIKELY(Header.State != Chunk::State::Allocated)) |
| reportInvalidChunkState(AllocatorAction::Deallocating, Ptr); |
| DCHECK_EQ(Header.ClassId, QuarantineClassId); |
| DCHECK_EQ(Header.Offset, 0); |
| DCHECK_EQ(Header.SizeOrUnusedBytes, sizeof(QuarantineBatch)); |
| |
| Chunk::UnpackedHeader NewHeader = Header; |
| NewHeader.State = Chunk::State::Available; |
| Chunk::compareExchangeHeader(Allocator.Cookie, Ptr, &NewHeader, &Header); |
| Cache.deallocate(QuarantineClassId, |
| reinterpret_cast<void *>(reinterpret_cast<uptr>(Ptr) - |
| Chunk::getHeaderSize())); |
| } |
| |
| private: |
| ThisT &Allocator; |
| CacheT &Cache; |
| }; |
| |
| typedef GlobalQuarantine<QuarantineCallback, void> QuarantineT; |
| typedef typename QuarantineT::CacheT QuarantineCacheT; |
| |
| void initLinkerInitialized() { |
| performSanityChecks(); |
| |
| // Check if hardware CRC32 is supported in the binary and by the platform, |
| // if so, opt for the CRC32 hardware version of the checksum. |
| if (&computeHardwareCRC32 && hasHardwareCRC32()) |
| HashAlgorithm = Checksum::HardwareCRC32; |
| |
| if (UNLIKELY(!getRandom(&Cookie, sizeof(Cookie)))) |
| Cookie = static_cast<u32>(getMonotonicTime() ^ |
| (reinterpret_cast<uptr>(this) >> 4)); |
| |
| initFlags(); |
| reportUnrecognizedFlags(); |
| |
| // Store some flags locally. |
| Options.MayReturnNull = getFlags()->may_return_null; |
| Options.ZeroContents = getFlags()->zero_contents; |
| Options.DeallocTypeMismatch = getFlags()->dealloc_type_mismatch; |
| Options.DeleteSizeMismatch = getFlags()->delete_size_mismatch; |
| Options.QuarantineMaxChunkSize = |
| static_cast<u32>(getFlags()->quarantine_max_chunk_size); |
| |
| Stats.initLinkerInitialized(); |
| const s32 ReleaseToOsIntervalMs = getFlags()->release_to_os_interval_ms; |
| Primary.initLinkerInitialized(ReleaseToOsIntervalMs); |
| Secondary.initLinkerInitialized(&Stats, ReleaseToOsIntervalMs); |
| |
| Quarantine.init( |
| static_cast<uptr>(getFlags()->quarantine_size_kb << 10), |
| static_cast<uptr>(getFlags()->thread_local_quarantine_size_kb << 10)); |
| } |
| |
| // Initialize the embedded GWP-ASan instance. Requires the main allocator to |
| // be functional, best called from PostInitCallback. |
| void initGwpAsan() { |
| #ifdef GWP_ASAN_HOOKS |
| gwp_asan::options::Options Opt; |
| Opt.Enabled = getFlags()->GWP_ASAN_Enabled; |
| // Bear in mind - Scudo has its own alignment guarantees that are strictly |
| // enforced. Scudo exposes the same allocation function for everything from |
| // malloc() to posix_memalign, so in general this flag goes unused, as Scudo |
| // will always ask GWP-ASan for an aligned amount of bytes. |
| Opt.PerfectlyRightAlign = getFlags()->GWP_ASAN_PerfectlyRightAlign; |
| Opt.MaxSimultaneousAllocations = |
| getFlags()->GWP_ASAN_MaxSimultaneousAllocations; |
| Opt.SampleRate = getFlags()->GWP_ASAN_SampleRate; |
| Opt.InstallSignalHandlers = getFlags()->GWP_ASAN_InstallSignalHandlers; |
| // Embedded GWP-ASan is locked through the Scudo atfork handler (via |
| // Allocator::disable calling GWPASan.disable). Disable GWP-ASan's atfork |
| // handler. |
| Opt.InstallForkHandlers = false; |
| Opt.Backtrace = gwp_asan::options::getBacktraceFunction(); |
| GuardedAlloc.init(Opt); |
| |
| if (Opt.InstallSignalHandlers) |
| gwp_asan::crash_handler::installSignalHandlers( |
| &GuardedAlloc, Printf, gwp_asan::options::getPrintBacktraceFunction(), |
| Opt.Backtrace); |
| #endif // GWP_ASAN_HOOKS |
| } |
| |
| void reset() { memset(this, 0, sizeof(*this)); } |
| |
| void unmapTestOnly() { |
| TSDRegistry.unmapTestOnly(); |
| Primary.unmapTestOnly(); |
| #ifdef GWP_ASAN_HOOKS |
| if (getFlags()->GWP_ASAN_InstallSignalHandlers) |
| gwp_asan::crash_handler::uninstallSignalHandlers(); |
| GuardedAlloc.uninitTestOnly(); |
| #endif // GWP_ASAN_HOOKS |
| } |
| |
| TSDRegistryT *getTSDRegistry() { return &TSDRegistry; } |
| |
| // The Cache must be provided zero-initialized. |
| void initCache(CacheT *Cache) { |
| Cache->initLinkerInitialized(&Stats, &Primary); |
| } |
| |
| // Release the resources used by a TSD, which involves: |
| // - draining the local quarantine cache to the global quarantine; |
| // - releasing the cached pointers back to the Primary; |
| // - unlinking the local stats from the global ones (destroying the cache does |
| // the last two items). |
| void commitBack(TSD<ThisT> *TSD) { |
| Quarantine.drain(&TSD->QuarantineCache, |
| QuarantineCallback(*this, TSD->Cache)); |
| TSD->Cache.destroy(&Stats); |
| } |
| |
| ALWAYS_INLINE void *untagPointerMaybe(void *Ptr) { |
| if (Primary.SupportsMemoryTagging) |
| return reinterpret_cast<void *>( |
| untagPointer(reinterpret_cast<uptr>(Ptr))); |
| return Ptr; |
| } |
| |
| NOINLINE void *allocate(uptr Size, Chunk::Origin Origin, |
| uptr Alignment = MinAlignment, |
| bool ZeroContents = false) { |
| initThreadMaybe(); |
| |
| #ifdef GWP_ASAN_HOOKS |
| if (UNLIKELY(GuardedAlloc.shouldSample())) { |
| if (void *Ptr = GuardedAlloc.allocate(roundUpTo(Size, Alignment))) |
| return Ptr; |
| } |
| #endif // GWP_ASAN_HOOKS |
| |
| ZeroContents |= static_cast<bool>(Options.ZeroContents); |
| |
| if (UNLIKELY(Alignment > MaxAlignment)) { |
| if (Options.MayReturnNull) |
| return nullptr; |
| reportAlignmentTooBig(Alignment, MaxAlignment); |
| } |
| if (Alignment < MinAlignment) |
| Alignment = MinAlignment; |
| |
| // If the requested size happens to be 0 (more common than you might think), |
| // allocate MinAlignment bytes on top of the header. Then add the extra |
| // bytes required to fulfill the alignment requirements: we allocate enough |
| // to be sure that there will be an address in the block that will satisfy |
| // the alignment. |
| const uptr NeededSize = |
| roundUpTo(Size, MinAlignment) + |
| ((Alignment > MinAlignment) ? Alignment : Chunk::getHeaderSize()); |
| |
| // Takes care of extravagantly large sizes as well as integer overflows. |
| static_assert(MaxAllowedMallocSize < UINTPTR_MAX - MaxAlignment, ""); |
| if (UNLIKELY(Size >= MaxAllowedMallocSize)) { |
| if (Options.MayReturnNull) |
| return nullptr; |
| reportAllocationSizeTooBig(Size, NeededSize, MaxAllowedMallocSize); |
| } |
| DCHECK_LE(Size, NeededSize); |
| |
| void *Block; |
| uptr ClassId; |
| uptr SecondaryBlockEnd; |
| if (LIKELY(PrimaryT::canAllocate(NeededSize))) { |
| ClassId = SizeClassMap::getClassIdBySize(NeededSize); |
| DCHECK_NE(ClassId, 0U); |
| bool UnlockRequired; |
| auto *TSD = TSDRegistry.getTSDAndLock(&UnlockRequired); |
| Block = TSD->Cache.allocate(ClassId); |
| if (UnlockRequired) |
| TSD->unlock(); |
| } else { |
| ClassId = 0; |
| Block = Secondary.allocate(NeededSize, Alignment, &SecondaryBlockEnd, |
| ZeroContents); |
| } |
| |
| if (UNLIKELY(!Block)) { |
| if (Options.MayReturnNull) |
| return nullptr; |
| reportOutOfMemory(NeededSize); |
| } |
| |
| const uptr BlockUptr = reinterpret_cast<uptr>(Block); |
| const uptr UnalignedUserPtr = BlockUptr + Chunk::getHeaderSize(); |
| const uptr UserPtr = roundUpTo(UnalignedUserPtr, Alignment); |
| |
| void *Ptr = reinterpret_cast<void *>(UserPtr); |
| void *TaggedPtr = Ptr; |
| if (ClassId) { |
| // We only need to zero or tag the contents for Primary backed |
| // allocations. We only set tags for primary allocations in order to avoid |
| // faulting potentially large numbers of pages for large secondary |
| // allocations. We assume that guard pages are enough to protect these |
| // allocations. |
| // |
| // FIXME: When the kernel provides a way to set the background tag of a |
| // mapping, we should be able to tag secondary allocations as well. |
| // |
| // When memory tagging is enabled, zeroing the contents is done as part of |
| // setting the tag. |
| if (UNLIKELY(useMemoryTagging())) { |
| uptr PrevUserPtr; |
| Chunk::UnpackedHeader Header; |
| const uptr BlockEnd = BlockUptr + PrimaryT::getSizeByClassId(ClassId); |
| // If possible, try to reuse the UAF tag that was set by deallocate(). |
| // For simplicity, only reuse tags if we have the same start address as |
| // the previous allocation. This handles the majority of cases since |
| // most allocations will not be more aligned than the minimum alignment. |
| // |
| // We need to handle situations involving reclaimed chunks, and retag |
| // the reclaimed portions if necessary. In the case where the chunk is |
| // fully reclaimed, the chunk's header will be zero, which will trigger |
| // the code path for new mappings and invalid chunks that prepares the |
| // chunk from scratch. There are three possibilities for partial |
| // reclaiming: |
| // |
| // (1) Header was reclaimed, data was partially reclaimed. |
| // (2) Header was not reclaimed, all data was reclaimed (e.g. because |
| // data started on a page boundary). |
| // (3) Header was not reclaimed, data was partially reclaimed. |
| // |
| // Case (1) will be handled in the same way as for full reclaiming, |
| // since the header will be zero. |
| // |
| // We can detect case (2) by loading the tag from the start |
| // of the chunk. If it is zero, it means that either all data was |
| // reclaimed (since we never use zero as the chunk tag), or that the |
| // previous allocation was of size zero. Either way, we need to prepare |
| // a new chunk from scratch. |
| // |
| // We can detect case (3) by moving to the next page (if covered by the |
| // chunk) and loading the tag of its first granule. If it is zero, it |
| // means that all following pages may need to be retagged. On the other |
| // hand, if it is nonzero, we can assume that all following pages are |
| // still tagged, according to the logic that if any of the pages |
| // following the next page were reclaimed, the next page would have been |
| // reclaimed as well. |
| uptr TaggedUserPtr; |
| if (getChunkFromBlock(BlockUptr, &PrevUserPtr, &Header) && |
| PrevUserPtr == UserPtr && |
| (TaggedUserPtr = loadTag(UserPtr)) != UserPtr) { |
| uptr PrevEnd = TaggedUserPtr + Header.SizeOrUnusedBytes; |
| const uptr NextPage = roundUpTo(TaggedUserPtr, getPageSizeCached()); |
| if (NextPage < PrevEnd && loadTag(NextPage) != NextPage) |
| PrevEnd = NextPage; |
| TaggedPtr = reinterpret_cast<void *>(TaggedUserPtr); |
| resizeTaggedChunk(PrevEnd, TaggedUserPtr + Size, BlockEnd); |
| } else { |
| TaggedPtr = prepareTaggedChunk(Ptr, Size, BlockEnd); |
| } |
| } else if (UNLIKELY(ZeroContents)) { |
| // This condition is not necessarily unlikely, but since memset is |
| // costly, we might as well mark it as such. |
| memset(Block, 0, PrimaryT::getSizeByClassId(ClassId)); |
| } |
| } |
| |
| Chunk::UnpackedHeader Header = {}; |
| if (UNLIKELY(UnalignedUserPtr != UserPtr)) { |
| const uptr Offset = UserPtr - UnalignedUserPtr; |
| DCHECK_GE(Offset, 2 * sizeof(u32)); |
| // The BlockMarker has no security purpose, but is specifically meant for |
| // the chunk iteration function that can be used in debugging situations. |
| // It is the only situation where we have to locate the start of a chunk |
| // based on its block address. |
| reinterpret_cast<u32 *>(Block)[0] = BlockMarker; |
| reinterpret_cast<u32 *>(Block)[1] = static_cast<u32>(Offset); |
| Header.Offset = (Offset >> MinAlignmentLog) & Chunk::OffsetMask; |
| } |
| Header.ClassId = ClassId & Chunk::ClassIdMask; |
| Header.State = Chunk::State::Allocated; |
| Header.Origin = Origin & Chunk::OriginMask; |
| Header.SizeOrUnusedBytes = |
| (ClassId ? Size : SecondaryBlockEnd - (UserPtr + Size)) & |
| Chunk::SizeOrUnusedBytesMask; |
| Chunk::storeHeader(Cookie, Ptr, &Header); |
| |
| if (&__scudo_allocate_hook) |
| __scudo_allocate_hook(TaggedPtr, Size); |
| |
| return TaggedPtr; |
| } |
| |
| NOINLINE void deallocate(void *Ptr, Chunk::Origin Origin, uptr DeleteSize = 0, |
| UNUSED uptr Alignment = MinAlignment) { |
| // 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); |
| |
| #ifdef GWP_ASAN_HOOKS |
| if (UNLIKELY(GuardedAlloc.pointerIsMine(Ptr))) { |
| GuardedAlloc.deallocate(Ptr); |
| return; |
| } |
| #endif // GWP_ASAN_HOOKS |
| |
| if (&__scudo_deallocate_hook) |
| __scudo_deallocate_hook(Ptr); |
| |
| if (UNLIKELY(!Ptr)) |
| return; |
| if (UNLIKELY(!isAligned(reinterpret_cast<uptr>(Ptr), MinAlignment))) |
| reportMisalignedPointer(AllocatorAction::Deallocating, Ptr); |
| |
| Ptr = untagPointerMaybe(Ptr); |
| |
| Chunk::UnpackedHeader Header; |
| Chunk::loadHeader(Cookie, Ptr, &Header); |
| |
| if (UNLIKELY(Header.State != Chunk::State::Allocated)) |
| reportInvalidChunkState(AllocatorAction::Deallocating, Ptr); |
| if (Options.DeallocTypeMismatch) { |
| if (Header.Origin != Origin) { |
| // With the exception of memalign'd chunks, that can be still be free'd. |
| if (UNLIKELY(Header.Origin != Chunk::Origin::Memalign || |
| Origin != Chunk::Origin::Malloc)) |
| reportDeallocTypeMismatch(AllocatorAction::Deallocating, Ptr, |
| Header.Origin, Origin); |
| } |
| } |
| |
| const uptr Size = getSize(Ptr, &Header); |
| if (DeleteSize && Options.DeleteSizeMismatch) { |
| if (UNLIKELY(DeleteSize != Size)) |
| reportDeleteSizeMismatch(Ptr, DeleteSize, Size); |
| } |
| |
| quarantineOrDeallocateChunk(Ptr, &Header, Size); |
| } |
| |
| void *reallocate(void *OldPtr, uptr NewSize, uptr Alignment = MinAlignment) { |
| initThreadMaybe(); |
| |
| void *OldTaggedPtr = OldPtr; |
| OldPtr = untagPointerMaybe(OldPtr); |
| |
| // The following cases are handled by the C wrappers. |
| DCHECK_NE(OldPtr, nullptr); |
| DCHECK_NE(NewSize, 0); |
| |
| #ifdef GWP_ASAN_HOOKS |
| if (UNLIKELY(GuardedAlloc.pointerIsMine(OldPtr))) { |
| uptr OldSize = GuardedAlloc.getSize(OldPtr); |
| void *NewPtr = allocate(NewSize, Chunk::Origin::Malloc, Alignment); |
| if (NewPtr) |
| memcpy(NewPtr, OldPtr, (NewSize < OldSize) ? NewSize : OldSize); |
| GuardedAlloc.deallocate(OldPtr); |
| return NewPtr; |
| } |
| #endif // GWP_ASAN_HOOKS |
| |
| if (UNLIKELY(!isAligned(reinterpret_cast<uptr>(OldPtr), MinAlignment))) |
| reportMisalignedPointer(AllocatorAction::Reallocating, OldPtr); |
| |
| Chunk::UnpackedHeader OldHeader; |
| Chunk::loadHeader(Cookie, OldPtr, &OldHeader); |
| |
| if (UNLIKELY(OldHeader.State != Chunk::State::Allocated)) |
| reportInvalidChunkState(AllocatorAction::Reallocating, OldPtr); |
| |
| // Pointer has to be allocated with a malloc-type function. Some |
| // applications think that it is OK to realloc a memalign'ed pointer, which |
| // will trigger this check. It really isn't. |
| if (Options.DeallocTypeMismatch) { |
| if (UNLIKELY(OldHeader.Origin != Chunk::Origin::Malloc)) |
| reportDeallocTypeMismatch(AllocatorAction::Reallocating, OldPtr, |
| OldHeader.Origin, Chunk::Origin::Malloc); |
| } |
| |
| void *BlockBegin = getBlockBegin(OldPtr, &OldHeader); |
| uptr BlockEnd; |
| uptr OldSize; |
| const uptr ClassId = OldHeader.ClassId; |
| if (LIKELY(ClassId)) { |
| BlockEnd = reinterpret_cast<uptr>(BlockBegin) + |
| SizeClassMap::getSizeByClassId(ClassId); |
| OldSize = OldHeader.SizeOrUnusedBytes; |
| } else { |
| BlockEnd = SecondaryT::getBlockEnd(BlockBegin); |
| OldSize = BlockEnd - |
| (reinterpret_cast<uptr>(OldPtr) + OldHeader.SizeOrUnusedBytes); |
| } |
| // If the new chunk still fits in the previously allocated block (with a |
| // reasonable delta), we just keep the old block, and update the chunk |
| // header to reflect the size change. |
| if (reinterpret_cast<uptr>(OldPtr) + NewSize <= BlockEnd) { |
| const uptr Delta = |
| OldSize < NewSize ? NewSize - OldSize : OldSize - NewSize; |
| if (Delta <= SizeClassMap::MaxSize / 2) { |
| Chunk::UnpackedHeader NewHeader = OldHeader; |
| NewHeader.SizeOrUnusedBytes = |
| (ClassId ? NewSize |
| : BlockEnd - (reinterpret_cast<uptr>(OldPtr) + NewSize)) & |
| Chunk::SizeOrUnusedBytesMask; |
| Chunk::compareExchangeHeader(Cookie, OldPtr, &NewHeader, &OldHeader); |
| if (UNLIKELY(ClassId && useMemoryTagging())) |
| resizeTaggedChunk(reinterpret_cast<uptr>(OldTaggedPtr) + OldSize, |
| reinterpret_cast<uptr>(OldTaggedPtr) + NewSize, |
| BlockEnd); |
| return OldTaggedPtr; |
| } |
| } |
| |
| // Otherwise we allocate a new one, and deallocate the old one. Some |
| // allocators will allocate an even larger chunk (by a fixed factor) to |
| // allow for potential further in-place realloc. The gains of such a trick |
| // are currently unclear. |
| void *NewPtr = allocate(NewSize, Chunk::Origin::Malloc, Alignment); |
| if (NewPtr) { |
| const uptr OldSize = getSize(OldPtr, &OldHeader); |
| memcpy(NewPtr, OldTaggedPtr, Min(NewSize, OldSize)); |
| quarantineOrDeallocateChunk(OldPtr, &OldHeader, OldSize); |
| } |
| return NewPtr; |
| } |
| |
| // TODO(kostyak): disable() is currently best-effort. There are some small |
| // windows of time when an allocation could still succeed after |
| // this function finishes. We will revisit that later. |
| void disable() { |
| initThreadMaybe(); |
| #ifdef GWP_ASAN_HOOKS |
| GuardedAlloc.disable(); |
| #endif |
| TSDRegistry.disable(); |
| Stats.disable(); |
| Quarantine.disable(); |
| Primary.disable(); |
| Secondary.disable(); |
| } |
| |
| void enable() { |
| initThreadMaybe(); |
| Secondary.enable(); |
| Primary.enable(); |
| Quarantine.enable(); |
| Stats.enable(); |
| TSDRegistry.enable(); |
| #ifdef GWP_ASAN_HOOKS |
| GuardedAlloc.enable(); |
| #endif |
| } |
| |
| // The function returns the amount of bytes required to store the statistics, |
| // which might be larger than the amount of bytes provided. Note that the |
| // statistics buffer is not necessarily constant between calls to this |
| // function. This can be called with a null buffer or zero size for buffer |
| // sizing purposes. |
| uptr getStats(char *Buffer, uptr Size) { |
| ScopedString Str(1024); |
| disable(); |
| const uptr Length = getStats(&Str) + 1; |
| enable(); |
| if (Length < Size) |
| Size = Length; |
| if (Buffer && Size) { |
| memcpy(Buffer, Str.data(), Size); |
| Buffer[Size - 1] = '\0'; |
| } |
| return Length; |
| } |
| |
| void printStats() { |
| ScopedString Str(1024); |
| disable(); |
| getStats(&Str); |
| enable(); |
| Str.output(); |
| } |
| |
| void releaseToOS() { |
| initThreadMaybe(); |
| Primary.releaseToOS(); |
| Secondary.releaseToOS(); |
| } |
| |
| // Iterate over all chunks and call a callback for all busy chunks located |
| // within the provided memory range. Said callback must not use this allocator |
| // or a deadlock can ensue. This fits Android's malloc_iterate() needs. |
| void iterateOverChunks(uptr Base, uptr Size, iterate_callback Callback, |
| void *Arg) { |
| initThreadMaybe(); |
| const uptr From = Base; |
| const uptr To = Base + Size; |
| auto Lambda = [this, From, To, Callback, Arg](uptr Block) { |
| if (Block < From || Block >= To) |
| return; |
| uptr Chunk; |
| Chunk::UnpackedHeader Header; |
| if (getChunkFromBlock(Block, &Chunk, &Header) && |
| Header.State == Chunk::State::Allocated) { |
| uptr TaggedChunk = Chunk; |
| if (useMemoryTagging()) |
| TaggedChunk = loadTag(Chunk); |
| Callback(TaggedChunk, getSize(reinterpret_cast<void *>(Chunk), &Header), |
| Arg); |
| } |
| }; |
| Primary.iterateOverBlocks(Lambda); |
| Secondary.iterateOverBlocks(Lambda); |
| #ifdef GWP_ASAN_HOOKS |
| GuardedAlloc.iterate(reinterpret_cast<void *>(Base), Size, Callback, Arg); |
| #endif |
| } |
| |
| bool canReturnNull() { |
| initThreadMaybe(); |
| return Options.MayReturnNull; |
| } |
| |
| // TODO(kostyak): implement this as a "backend" to mallopt. |
| bool setOption(UNUSED uptr Option, UNUSED uptr Value) { return false; } |
| |
| // Return the usable size for a given chunk. Technically we lie, as we just |
| // report the actual size of a chunk. This is done to counteract code actively |
| // writing past the end of a chunk (like sqlite3) when the usable size allows |
| // for it, which then forces realloc to copy the usable size of a chunk as |
| // opposed to its actual size. |
| uptr getUsableSize(const void *Ptr) { |
| initThreadMaybe(); |
| if (UNLIKELY(!Ptr)) |
| return 0; |
| |
| #ifdef GWP_ASAN_HOOKS |
| if (UNLIKELY(GuardedAlloc.pointerIsMine(Ptr))) |
| return GuardedAlloc.getSize(Ptr); |
| #endif // GWP_ASAN_HOOKS |
| |
| Ptr = untagPointerMaybe(const_cast<void *>(Ptr)); |
| Chunk::UnpackedHeader Header; |
| Chunk::loadHeader(Cookie, Ptr, &Header); |
| // Getting the usable size of a chunk only makes sense if it's allocated. |
| if (UNLIKELY(Header.State != Chunk::State::Allocated)) |
| reportInvalidChunkState(AllocatorAction::Sizing, const_cast<void *>(Ptr)); |
| return getSize(Ptr, &Header); |
| } |
| |
| void getStats(StatCounters S) { |
| initThreadMaybe(); |
| Stats.get(S); |
| } |
| |
| // Returns true if the pointer provided was allocated by the current |
| // allocator instance, which is compliant with tcmalloc's ownership concept. |
| // A corrupted chunk will not be reported as owned, which is WAI. |
| bool isOwned(const void *Ptr) { |
| initThreadMaybe(); |
| #ifdef GWP_ASAN_HOOKS |
| if (GuardedAlloc.pointerIsMine(Ptr)) |
| return true; |
| #endif // GWP_ASAN_HOOKS |
| if (!Ptr || !isAligned(reinterpret_cast<uptr>(Ptr), MinAlignment)) |
| return false; |
| Ptr = untagPointerMaybe(const_cast<void *>(Ptr)); |
| Chunk::UnpackedHeader Header; |
| return Chunk::isValid(Cookie, Ptr, &Header) && |
| Header.State == Chunk::State::Allocated; |
| } |
| |
| bool useMemoryTagging() { return Primary.useMemoryTagging(); } |
| |
| void disableMemoryTagging() { Primary.disableMemoryTagging(); } |
| |
| private: |
| using SecondaryT = typename Params::Secondary; |
| typedef typename PrimaryT::SizeClassMap SizeClassMap; |
| |
| static const uptr MinAlignmentLog = SCUDO_MIN_ALIGNMENT_LOG; |
| static const uptr MaxAlignmentLog = 24U; // 16 MB seems reasonable. |
| static const uptr MinAlignment = 1UL << MinAlignmentLog; |
| static const uptr MaxAlignment = 1UL << MaxAlignmentLog; |
| static const uptr MaxAllowedMallocSize = |
| FIRST_32_SECOND_64(1UL << 31, 1ULL << 40); |
| |
| static_assert(MinAlignment >= sizeof(Chunk::PackedHeader), |
| "Minimal alignment must at least cover a chunk header."); |
| static_assert(!PrimaryT::SupportsMemoryTagging || |
| MinAlignment >= archMemoryTagGranuleSize(), |
| ""); |
| |
| static const u32 BlockMarker = 0x44554353U; |
| |
| GlobalStats Stats; |
| TSDRegistryT TSDRegistry; |
| PrimaryT Primary; |
| SecondaryT Secondary; |
| QuarantineT Quarantine; |
| |
| u32 Cookie; |
| |
| struct { |
| u8 MayReturnNull : 1; // may_return_null |
| u8 ZeroContents : 1; // zero_contents |
| u8 DeallocTypeMismatch : 1; // dealloc_type_mismatch |
| u8 DeleteSizeMismatch : 1; // delete_size_mismatch |
| u32 QuarantineMaxChunkSize; // quarantine_max_chunk_size |
| } Options; |
| |
| #ifdef GWP_ASAN_HOOKS |
| gwp_asan::GuardedPoolAllocator GuardedAlloc; |
| #endif // GWP_ASAN_HOOKS |
| |
| // The following might get optimized out by the compiler. |
| NOINLINE void performSanityChecks() { |
| // Verify that the header offset field can hold the maximum offset. In the |
| // case of the Secondary allocator, it takes care of alignment and the |
| // offset will always be small. In the case of the Primary, the worst case |
| // scenario happens in the last size class, when the backend allocation |
| // would already be aligned on the requested alignment, which would happen |
| // to be the maximum alignment that would fit in that size class. As a |
| // result, the maximum offset will be at most the maximum alignment for the |
| // last size class minus the header size, in multiples of MinAlignment. |
| Chunk::UnpackedHeader Header = {}; |
| const uptr MaxPrimaryAlignment = 1UL << getMostSignificantSetBitIndex( |
| SizeClassMap::MaxSize - MinAlignment); |
| const uptr MaxOffset = |
| (MaxPrimaryAlignment - Chunk::getHeaderSize()) >> MinAlignmentLog; |
| Header.Offset = MaxOffset & Chunk::OffsetMask; |
| if (UNLIKELY(Header.Offset != MaxOffset)) |
| reportSanityCheckError("offset"); |
| |
| // Verify that we can fit the maximum size or amount of unused bytes in the |
| // header. Given that the Secondary fits the allocation to a page, the worst |
| // case scenario happens in the Primary. It will depend on the second to |
| // last and last class sizes, as well as the dynamic base for the Primary. |
| // The following is an over-approximation that works for our needs. |
| const uptr MaxSizeOrUnusedBytes = SizeClassMap::MaxSize - 1; |
| Header.SizeOrUnusedBytes = MaxSizeOrUnusedBytes; |
| if (UNLIKELY(Header.SizeOrUnusedBytes != MaxSizeOrUnusedBytes)) |
| reportSanityCheckError("size (or unused bytes)"); |
| |
| const uptr LargestClassId = SizeClassMap::LargestClassId; |
| Header.ClassId = LargestClassId; |
| if (UNLIKELY(Header.ClassId != LargestClassId)) |
| reportSanityCheckError("class ID"); |
| } |
| |
| static inline void *getBlockBegin(const void *Ptr, |
| Chunk::UnpackedHeader *Header) { |
| return reinterpret_cast<void *>( |
| reinterpret_cast<uptr>(Ptr) - Chunk::getHeaderSize() - |
| (static_cast<uptr>(Header->Offset) << MinAlignmentLog)); |
| } |
| |
| // Return the size of a chunk as requested during its allocation. |
| inline uptr getSize(const void *Ptr, Chunk::UnpackedHeader *Header) { |
| const uptr SizeOrUnusedBytes = Header->SizeOrUnusedBytes; |
| if (LIKELY(Header->ClassId)) |
| return SizeOrUnusedBytes; |
| return SecondaryT::getBlockEnd(getBlockBegin(Ptr, Header)) - |
| reinterpret_cast<uptr>(Ptr) - SizeOrUnusedBytes; |
| } |
| |
| ALWAYS_INLINE void initThreadMaybe(bool MinimalInit = false) { |
| TSDRegistry.initThreadMaybe(this, MinimalInit); |
| } |
| |
| void quarantineOrDeallocateChunk(void *Ptr, Chunk::UnpackedHeader *Header, |
| uptr Size) { |
| Chunk::UnpackedHeader NewHeader = *Header; |
| if (UNLIKELY(NewHeader.ClassId && useMemoryTagging())) { |
| uptr TaggedBegin, TaggedEnd; |
| setRandomTag(Ptr, Size, &TaggedBegin, &TaggedEnd); |
| } |
| // If the quarantine is disabled, the actual size of a chunk is 0 or larger |
| // than the maximum allowed, we return a chunk directly to the backend. |
| // Logical Or can be short-circuited, which introduces unnecessary |
| // conditional jumps, so use bitwise Or and let the compiler be clever. |
| const bool BypassQuarantine = !Quarantine.getCacheSize() | !Size | |
| (Size > Options.QuarantineMaxChunkSize); |
| if (BypassQuarantine) { |
| NewHeader.State = Chunk::State::Available; |
| Chunk::compareExchangeHeader(Cookie, Ptr, &NewHeader, Header); |
| void *BlockBegin = getBlockBegin(Ptr, &NewHeader); |
| const uptr ClassId = NewHeader.ClassId; |
| if (LIKELY(ClassId)) { |
| bool UnlockRequired; |
| auto *TSD = TSDRegistry.getTSDAndLock(&UnlockRequired); |
| TSD->Cache.deallocate(ClassId, BlockBegin); |
| if (UnlockRequired) |
| TSD->unlock(); |
| } else { |
| Secondary.deallocate(BlockBegin); |
| } |
| } else { |
| NewHeader.State = Chunk::State::Quarantined; |
| Chunk::compareExchangeHeader(Cookie, Ptr, &NewHeader, Header); |
| bool UnlockRequired; |
| auto *TSD = TSDRegistry.getTSDAndLock(&UnlockRequired); |
| Quarantine.put(&TSD->QuarantineCache, |
| QuarantineCallback(*this, TSD->Cache), Ptr, Size); |
| if (UnlockRequired) |
| TSD->unlock(); |
| } |
| } |
| |
| bool getChunkFromBlock(uptr Block, uptr *Chunk, |
| Chunk::UnpackedHeader *Header) { |
| u32 Offset = 0; |
| if (reinterpret_cast<u32 *>(Block)[0] == BlockMarker) |
| Offset = reinterpret_cast<u32 *>(Block)[1]; |
| *Chunk = Block + Offset + Chunk::getHeaderSize(); |
| return Chunk::isValid(Cookie, reinterpret_cast<void *>(*Chunk), Header); |
| } |
| |
| uptr getStats(ScopedString *Str) { |
| Primary.getStats(Str); |
| Secondary.getStats(Str); |
| Quarantine.getStats(Str); |
| return Str->length(); |
| } |
| }; |
| |
| } // namespace scudo |
| |
| #endif // SCUDO_COMBINED_H_ |
