forked from OSchip/llvm-project
1056 lines
40 KiB
C++
1056 lines
40 KiB
C++
//===-- combined.h ----------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef SCUDO_COMBINED_H_
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#define SCUDO_COMBINED_H_
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#include "chunk.h"
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#include "common.h"
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#include "flags.h"
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#include "flags_parser.h"
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#include "local_cache.h"
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#include "memtag.h"
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#include "quarantine.h"
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#include "report.h"
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#include "secondary.h"
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#include "stack_depot.h"
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#include "string_utils.h"
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#include "tsd.h"
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#include "scudo/interface.h"
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#ifdef GWP_ASAN_HOOKS
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#include "gwp_asan/guarded_pool_allocator.h"
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#include "gwp_asan/optional/backtrace.h"
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#include "gwp_asan/optional/segv_handler.h"
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#endif // GWP_ASAN_HOOKS
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extern "C" inline void EmptyCallback() {}
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#ifdef HAVE_ANDROID_UNSAFE_FRAME_POINTER_CHASE
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// This function is not part of the NDK so it does not appear in any public
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// header files. We only declare/use it when targeting the platform.
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extern "C" size_t android_unsafe_frame_pointer_chase(scudo::uptr *buf,
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size_t num_entries);
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#endif
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namespace scudo {
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enum class Option { ReleaseInterval };
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template <class Params, void (*PostInitCallback)(void) = EmptyCallback>
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class Allocator {
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public:
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using PrimaryT = typename Params::Primary;
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using CacheT = typename PrimaryT::CacheT;
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typedef Allocator<Params, PostInitCallback> ThisT;
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typedef typename Params::template TSDRegistryT<ThisT> TSDRegistryT;
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void callPostInitCallback() {
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static pthread_once_t OnceControl = PTHREAD_ONCE_INIT;
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pthread_once(&OnceControl, PostInitCallback);
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}
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struct QuarantineCallback {
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explicit QuarantineCallback(ThisT &Instance, CacheT &LocalCache)
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: Allocator(Instance), Cache(LocalCache) {}
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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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Chunk::UnpackedHeader Header;
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Chunk::loadHeader(Allocator.Cookie, Ptr, &Header);
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if (UNLIKELY(Header.State != Chunk::State::Quarantined))
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reportInvalidChunkState(AllocatorAction::Recycling, Ptr);
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Chunk::UnpackedHeader NewHeader = Header;
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NewHeader.State = Chunk::State::Available;
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Chunk::compareExchangeHeader(Allocator.Cookie, Ptr, &NewHeader, &Header);
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void *BlockBegin = Allocator::getBlockBegin(Ptr, &NewHeader);
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const uptr ClassId = NewHeader.ClassId;
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if (LIKELY(ClassId))
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Cache.deallocate(ClassId, BlockBegin);
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else
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Allocator.Secondary.deallocate(BlockBegin);
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}
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// We take a shortcut when allocating a quarantine batch by working with the
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// appropriate class ID instead of using Size. The compiler should optimize
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// the class ID computation and work with the associated cache directly.
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void *allocate(UNUSED uptr Size) {
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const uptr QuarantineClassId = SizeClassMap::getClassIdBySize(
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sizeof(QuarantineBatch) + Chunk::getHeaderSize());
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void *Ptr = Cache.allocate(QuarantineClassId);
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// Quarantine batch allocation failure is fatal.
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if (UNLIKELY(!Ptr))
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reportOutOfMemory(SizeClassMap::getSizeByClassId(QuarantineClassId));
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Ptr = reinterpret_cast<void *>(reinterpret_cast<uptr>(Ptr) +
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Chunk::getHeaderSize());
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Chunk::UnpackedHeader Header = {};
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Header.ClassId = QuarantineClassId & Chunk::ClassIdMask;
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Header.SizeOrUnusedBytes = sizeof(QuarantineBatch);
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Header.State = Chunk::State::Allocated;
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Chunk::storeHeader(Allocator.Cookie, Ptr, &Header);
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return Ptr;
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}
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void deallocate(void *Ptr) {
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const uptr QuarantineClassId = SizeClassMap::getClassIdBySize(
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sizeof(QuarantineBatch) + Chunk::getHeaderSize());
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Chunk::UnpackedHeader Header;
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Chunk::loadHeader(Allocator.Cookie, Ptr, &Header);
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if (UNLIKELY(Header.State != Chunk::State::Allocated))
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reportInvalidChunkState(AllocatorAction::Deallocating, Ptr);
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DCHECK_EQ(Header.ClassId, QuarantineClassId);
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DCHECK_EQ(Header.Offset, 0);
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DCHECK_EQ(Header.SizeOrUnusedBytes, sizeof(QuarantineBatch));
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Chunk::UnpackedHeader NewHeader = Header;
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NewHeader.State = Chunk::State::Available;
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Chunk::compareExchangeHeader(Allocator.Cookie, Ptr, &NewHeader, &Header);
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Cache.deallocate(QuarantineClassId,
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reinterpret_cast<void *>(reinterpret_cast<uptr>(Ptr) -
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Chunk::getHeaderSize()));
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}
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private:
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ThisT &Allocator;
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CacheT &Cache;
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};
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typedef GlobalQuarantine<QuarantineCallback, void> QuarantineT;
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typedef typename QuarantineT::CacheT QuarantineCacheT;
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void initLinkerInitialized() {
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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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HashAlgorithm = Checksum::HardwareCRC32;
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if (UNLIKELY(!getRandom(&Cookie, sizeof(Cookie))))
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Cookie = static_cast<u32>(getMonotonicTime() ^
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(reinterpret_cast<uptr>(this) >> 4));
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initFlags();
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reportUnrecognizedFlags();
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// Store some flags locally.
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Options.MayReturnNull = getFlags()->may_return_null;
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Options.ZeroContents = getFlags()->zero_contents;
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Options.DeallocTypeMismatch = getFlags()->dealloc_type_mismatch;
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Options.DeleteSizeMismatch = getFlags()->delete_size_mismatch;
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Options.TrackAllocationStacks = false;
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Options.QuarantineMaxChunkSize =
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static_cast<u32>(getFlags()->quarantine_max_chunk_size);
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Stats.initLinkerInitialized();
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const s32 ReleaseToOsIntervalMs = getFlags()->release_to_os_interval_ms;
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Primary.initLinkerInitialized(ReleaseToOsIntervalMs);
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Secondary.initLinkerInitialized(&Stats, ReleaseToOsIntervalMs);
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Quarantine.init(
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static_cast<uptr>(getFlags()->quarantine_size_kb << 10),
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static_cast<uptr>(getFlags()->thread_local_quarantine_size_kb << 10));
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}
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// Initialize the embedded GWP-ASan instance. Requires the main allocator to
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// be functional, best called from PostInitCallback.
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void initGwpAsan() {
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#ifdef GWP_ASAN_HOOKS
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gwp_asan::options::Options Opt;
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Opt.Enabled = getFlags()->GWP_ASAN_Enabled;
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// Bear in mind - Scudo has its own alignment guarantees that are strictly
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// enforced. Scudo exposes the same allocation function for everything from
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// malloc() to posix_memalign, so in general this flag goes unused, as Scudo
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// will always ask GWP-ASan for an aligned amount of bytes.
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Opt.PerfectlyRightAlign = getFlags()->GWP_ASAN_PerfectlyRightAlign;
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Opt.MaxSimultaneousAllocations =
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getFlags()->GWP_ASAN_MaxSimultaneousAllocations;
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Opt.SampleRate = getFlags()->GWP_ASAN_SampleRate;
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Opt.InstallSignalHandlers = getFlags()->GWP_ASAN_InstallSignalHandlers;
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// Embedded GWP-ASan is locked through the Scudo atfork handler (via
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// Allocator::disable calling GWPASan.disable). Disable GWP-ASan's atfork
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// handler.
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Opt.InstallForkHandlers = false;
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Opt.Backtrace = gwp_asan::options::getBacktraceFunction();
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GuardedAlloc.init(Opt);
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if (Opt.InstallSignalHandlers)
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gwp_asan::crash_handler::installSignalHandlers(
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&GuardedAlloc, Printf, gwp_asan::options::getPrintBacktraceFunction(),
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Opt.Backtrace);
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#endif // GWP_ASAN_HOOKS
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}
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void reset() { memset(this, 0, sizeof(*this)); }
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void unmapTestOnly() {
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TSDRegistry.unmapTestOnly();
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Primary.unmapTestOnly();
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#ifdef GWP_ASAN_HOOKS
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if (getFlags()->GWP_ASAN_InstallSignalHandlers)
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gwp_asan::crash_handler::uninstallSignalHandlers();
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GuardedAlloc.uninitTestOnly();
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#endif // GWP_ASAN_HOOKS
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}
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TSDRegistryT *getTSDRegistry() { return &TSDRegistry; }
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// The Cache must be provided zero-initialized.
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void initCache(CacheT *Cache) {
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Cache->initLinkerInitialized(&Stats, &Primary);
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}
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// Release the resources used by a TSD, which involves:
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// - draining the local quarantine cache to the global quarantine;
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// - releasing the cached pointers back to the Primary;
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// - unlinking the local stats from the global ones (destroying the cache does
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// the last two items).
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void commitBack(TSD<ThisT> *TSD) {
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Quarantine.drain(&TSD->QuarantineCache,
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QuarantineCallback(*this, TSD->Cache));
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TSD->Cache.destroy(&Stats);
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}
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ALWAYS_INLINE void *untagPointerMaybe(void *Ptr) {
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if (Primary.SupportsMemoryTagging)
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return reinterpret_cast<void *>(
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untagPointer(reinterpret_cast<uptr>(Ptr)));
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return Ptr;
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}
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NOINLINE u32 collectStackTrace() {
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#ifdef HAVE_ANDROID_UNSAFE_FRAME_POINTER_CHASE
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// Discard collectStackTrace() frame and allocator function frame.
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constexpr uptr DiscardFrames = 2;
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uptr Stack[MaxTraceSize + DiscardFrames];
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uptr Size =
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android_unsafe_frame_pointer_chase(Stack, MaxTraceSize + DiscardFrames);
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Size = Min<uptr>(Size, MaxTraceSize + DiscardFrames);
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return Depot.insert(Stack + Min<uptr>(DiscardFrames, Size), Stack + Size);
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#else
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return 0;
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#endif
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}
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NOINLINE void *allocate(uptr Size, Chunk::Origin Origin,
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uptr Alignment = MinAlignment,
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bool ZeroContents = false) {
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initThreadMaybe();
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#ifdef GWP_ASAN_HOOKS
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if (UNLIKELY(GuardedAlloc.shouldSample())) {
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if (void *Ptr = GuardedAlloc.allocate(roundUpTo(Size, Alignment)))
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return Ptr;
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}
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#endif // GWP_ASAN_HOOKS
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ZeroContents |= static_cast<bool>(Options.ZeroContents);
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if (UNLIKELY(Alignment > MaxAlignment)) {
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if (Options.MayReturnNull)
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return nullptr;
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reportAlignmentTooBig(Alignment, MaxAlignment);
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}
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if (Alignment < MinAlignment)
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Alignment = MinAlignment;
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// If the requested size happens to be 0 (more common than you might think),
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// allocate MinAlignment bytes on top of the header. Then add the extra
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// bytes required to fulfill the alignment requirements: we allocate enough
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// to be sure that there will be an address in the block that will satisfy
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// the alignment.
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const uptr NeededSize =
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roundUpTo(Size, MinAlignment) +
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((Alignment > MinAlignment) ? Alignment : Chunk::getHeaderSize());
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// Takes care of extravagantly large sizes as well as integer overflows.
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static_assert(MaxAllowedMallocSize < UINTPTR_MAX - MaxAlignment, "");
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if (UNLIKELY(Size >= MaxAllowedMallocSize)) {
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if (Options.MayReturnNull)
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return nullptr;
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reportAllocationSizeTooBig(Size, NeededSize, MaxAllowedMallocSize);
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}
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DCHECK_LE(Size, NeededSize);
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void *Block = nullptr;
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uptr ClassId = 0;
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uptr SecondaryBlockEnd;
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if (LIKELY(PrimaryT::canAllocate(NeededSize))) {
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ClassId = SizeClassMap::getClassIdBySize(NeededSize);
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DCHECK_NE(ClassId, 0U);
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bool UnlockRequired;
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auto *TSD = TSDRegistry.getTSDAndLock(&UnlockRequired);
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Block = TSD->Cache.allocate(ClassId);
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// If the allocation failed, the most likely reason with a 64-bit primary
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// is the region being full. In that event, retry once using the
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// immediately larger class (except if the failing class was already the
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// largest). This will waste some memory but will allow the application to
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// not fail. If dealing with the largest class, fallback to the Secondary.
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if (UNLIKELY(!Block)) {
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if (ClassId < SizeClassMap::LargestClassId)
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Block = TSD->Cache.allocate(++ClassId);
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else
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ClassId = 0;
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}
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if (UnlockRequired)
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TSD->unlock();
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}
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if (UNLIKELY(ClassId == 0))
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Block = Secondary.allocate(NeededSize, Alignment, &SecondaryBlockEnd,
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ZeroContents);
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if (UNLIKELY(!Block)) {
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if (Options.MayReturnNull)
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return nullptr;
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reportOutOfMemory(NeededSize);
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}
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const uptr BlockUptr = reinterpret_cast<uptr>(Block);
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const uptr UnalignedUserPtr = BlockUptr + Chunk::getHeaderSize();
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const uptr UserPtr = roundUpTo(UnalignedUserPtr, Alignment);
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void *Ptr = reinterpret_cast<void *>(UserPtr);
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void *TaggedPtr = Ptr;
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if (ClassId) {
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// We only need to zero or tag the contents for Primary backed
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// allocations. We only set tags for primary allocations in order to avoid
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// faulting potentially large numbers of pages for large secondary
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// allocations. We assume that guard pages are enough to protect these
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// allocations.
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//
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// FIXME: When the kernel provides a way to set the background tag of a
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// mapping, we should be able to tag secondary allocations as well.
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//
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// When memory tagging is enabled, zeroing the contents is done as part of
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// setting the tag.
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if (UNLIKELY(useMemoryTagging())) {
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uptr PrevUserPtr;
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Chunk::UnpackedHeader Header;
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const uptr BlockEnd = BlockUptr + PrimaryT::getSizeByClassId(ClassId);
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// If possible, try to reuse the UAF tag that was set by deallocate().
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// For simplicity, only reuse tags if we have the same start address as
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// the previous allocation. This handles the majority of cases since
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// most allocations will not be more aligned than the minimum alignment.
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//
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// We need to handle situations involving reclaimed chunks, and retag
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// the reclaimed portions if necessary. In the case where the chunk is
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// fully reclaimed, the chunk's header will be zero, which will trigger
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// the code path for new mappings and invalid chunks that prepares the
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// chunk from scratch. There are three possibilities for partial
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// reclaiming:
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//
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// (1) Header was reclaimed, data was partially reclaimed.
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// (2) Header was not reclaimed, all data was reclaimed (e.g. because
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// data started on a page boundary).
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// (3) Header was not reclaimed, data was partially reclaimed.
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//
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// Case (1) will be handled in the same way as for full reclaiming,
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// since the header will be zero.
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//
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// We can detect case (2) by loading the tag from the start
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// of the chunk. If it is zero, it means that either all data was
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// reclaimed (since we never use zero as the chunk tag), or that the
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// previous allocation was of size zero. Either way, we need to prepare
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// a new chunk from scratch.
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//
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// We can detect case (3) by moving to the next page (if covered by the
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// chunk) and loading the tag of its first granule. If it is zero, it
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// means that all following pages may need to be retagged. On the other
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// hand, if it is nonzero, we can assume that all following pages are
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// still tagged, according to the logic that if any of the pages
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// following the next page were reclaimed, the next page would have been
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// reclaimed as well.
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uptr TaggedUserPtr;
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if (getChunkFromBlock(BlockUptr, &PrevUserPtr, &Header) &&
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PrevUserPtr == UserPtr &&
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(TaggedUserPtr = loadTag(UserPtr)) != UserPtr) {
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uptr PrevEnd = TaggedUserPtr + Header.SizeOrUnusedBytes;
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const uptr NextPage = roundUpTo(TaggedUserPtr, getPageSizeCached());
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if (NextPage < PrevEnd && loadTag(NextPage) != NextPage)
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PrevEnd = NextPage;
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TaggedPtr = reinterpret_cast<void *>(TaggedUserPtr);
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resizeTaggedChunk(PrevEnd, TaggedUserPtr + Size, BlockEnd);
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if (Size) {
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// Clear any stack metadata that may have previously been stored in
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// the chunk data.
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memset(TaggedPtr, 0, archMemoryTagGranuleSize());
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}
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} else {
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TaggedPtr = prepareTaggedChunk(Ptr, Size, BlockEnd);
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}
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storeAllocationStackMaybe(Ptr);
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} else if (UNLIKELY(ZeroContents)) {
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// This condition is not necessarily unlikely, but since memset is
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// costly, we might as well mark it as such.
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memset(Block, 0, PrimaryT::getSizeByClassId(ClassId));
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}
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}
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Chunk::UnpackedHeader Header = {};
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if (UNLIKELY(UnalignedUserPtr != UserPtr)) {
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const uptr Offset = UserPtr - UnalignedUserPtr;
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DCHECK_GE(Offset, 2 * sizeof(u32));
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// The BlockMarker has no security purpose, but is specifically meant for
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// the chunk iteration function that can be used in debugging situations.
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// It is the only situation where we have to locate the start of a chunk
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// based on its block address.
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reinterpret_cast<u32 *>(Block)[0] = BlockMarker;
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reinterpret_cast<u32 *>(Block)[1] = static_cast<u32>(Offset);
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Header.Offset = (Offset >> MinAlignmentLog) & Chunk::OffsetMask;
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}
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Header.ClassId = ClassId & Chunk::ClassIdMask;
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Header.State = Chunk::State::Allocated;
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Header.Origin = Origin & Chunk::OriginMask;
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Header.SizeOrUnusedBytes =
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(ClassId ? Size : SecondaryBlockEnd - (UserPtr + Size)) &
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Chunk::SizeOrUnusedBytesMask;
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Chunk::storeHeader(Cookie, Ptr, &Header);
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if (&__scudo_allocate_hook)
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__scudo_allocate_hook(TaggedPtr, Size);
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return TaggedPtr;
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}
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NOINLINE void deallocate(void *Ptr, Chunk::Origin Origin, uptr DeleteSize = 0,
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UNUSED uptr Alignment = MinAlignment) {
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// For a deallocation, we only ensure minimal initialization, meaning thread
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// local data will be left uninitialized for now (when using ELF TLS). The
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// fallback cache will be used instead. This is a workaround for a situation
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// where the only heap operation performed in a thread would be a free past
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// the TLS destructors, ending up in initialized thread specific data never
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// being destroyed properly. Any other heap operation will do a full init.
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initThreadMaybe(/*MinimalInit=*/true);
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#ifdef GWP_ASAN_HOOKS
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if (UNLIKELY(GuardedAlloc.pointerIsMine(Ptr))) {
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GuardedAlloc.deallocate(Ptr);
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return;
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}
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#endif // GWP_ASAN_HOOKS
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if (&__scudo_deallocate_hook)
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__scudo_deallocate_hook(Ptr);
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if (UNLIKELY(!Ptr))
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return;
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if (UNLIKELY(!isAligned(reinterpret_cast<uptr>(Ptr), MinAlignment)))
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reportMisalignedPointer(AllocatorAction::Deallocating, Ptr);
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Ptr = untagPointerMaybe(Ptr);
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Chunk::UnpackedHeader Header;
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Chunk::loadHeader(Cookie, Ptr, &Header);
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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();
|
|
|
|
if (UNLIKELY(NewSize >= MaxAllowedMallocSize)) {
|
|
if (Options.MayReturnNull)
|
|
return nullptr;
|
|
reportAllocationSizeTooBig(NewSize, 0, MaxAllowedMallocSize);
|
|
}
|
|
|
|
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) {
|
|
if (NewSize > OldSize || (OldSize - NewSize) < getPageSizeCached()) {
|
|
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);
|
|
storeAllocationStackMaybe(OldPtr);
|
|
}
|
|
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;
|
|
}
|
|
|
|
bool setOption(Option O, sptr Value) {
|
|
if (O == Option::ReleaseInterval) {
|
|
Primary.setReleaseToOsIntervalMs(static_cast<s32>(Value));
|
|
Secondary.setReleaseToOsIntervalMs(static_cast<s32>(Value));
|
|
return true;
|
|
}
|
|
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(); }
|
|
|
|
void setTrackAllocationStacks(bool Track) {
|
|
Options.TrackAllocationStacks = Track;
|
|
}
|
|
|
|
const char *getStackDepotAddress() const {
|
|
return reinterpret_cast<const char *>(&Depot);
|
|
}
|
|
|
|
const char *getRegionInfoArrayAddress() const {
|
|
return Primary.getRegionInfoArrayAddress();
|
|
}
|
|
|
|
static uptr getRegionInfoArraySize() {
|
|
return PrimaryT::getRegionInfoArraySize();
|
|
}
|
|
|
|
static void getErrorInfo(struct scudo_error_info *ErrorInfo,
|
|
uintptr_t FaultAddr, const char *DepotPtr,
|
|
const char *RegionInfoPtr, const char *Memory,
|
|
const char *MemoryTags, uintptr_t MemoryAddr,
|
|
size_t MemorySize) {
|
|
*ErrorInfo = {};
|
|
if (!PrimaryT::SupportsMemoryTagging ||
|
|
MemoryAddr + MemorySize < MemoryAddr)
|
|
return;
|
|
|
|
uptr UntaggedFaultAddr = untagPointer(FaultAddr);
|
|
u8 FaultAddrTag = extractTag(FaultAddr);
|
|
BlockInfo Info =
|
|
PrimaryT::findNearestBlock(RegionInfoPtr, UntaggedFaultAddr);
|
|
|
|
auto GetGranule = [&](uptr Addr, const char **Data, uint8_t *Tag) -> bool {
|
|
if (Addr < MemoryAddr ||
|
|
Addr + archMemoryTagGranuleSize() < Addr ||
|
|
Addr + archMemoryTagGranuleSize() > MemoryAddr + MemorySize)
|
|
return false;
|
|
*Data = &Memory[Addr - MemoryAddr];
|
|
*Tag = static_cast<u8>(
|
|
MemoryTags[(Addr - MemoryAddr) / archMemoryTagGranuleSize()]);
|
|
return true;
|
|
};
|
|
|
|
auto ReadBlock = [&](uptr Addr, uptr *ChunkAddr,
|
|
Chunk::UnpackedHeader *Header, const u32 **Data,
|
|
u8 *Tag) {
|
|
const char *BlockBegin;
|
|
u8 BlockBeginTag;
|
|
if (!GetGranule(Addr, &BlockBegin, &BlockBeginTag))
|
|
return false;
|
|
uptr ChunkOffset = getChunkOffsetFromBlock(BlockBegin);
|
|
*ChunkAddr = Addr + ChunkOffset;
|
|
|
|
const char *ChunkBegin;
|
|
if (!GetGranule(*ChunkAddr, &ChunkBegin, Tag))
|
|
return false;
|
|
*Header = *reinterpret_cast<const Chunk::UnpackedHeader *>(
|
|
ChunkBegin - Chunk::getHeaderSize());
|
|
*Data = reinterpret_cast<const u32 *>(ChunkBegin);
|
|
return true;
|
|
};
|
|
|
|
auto *Depot = reinterpret_cast<const StackDepot *>(DepotPtr);
|
|
|
|
auto MaybeCollectTrace = [&](uintptr_t(&Trace)[MaxTraceSize], u32 Hash) {
|
|
uptr RingPos, Size;
|
|
if (!Depot->find(Hash, &RingPos, &Size))
|
|
return;
|
|
for (unsigned I = 0; I != Size && I != MaxTraceSize; ++I)
|
|
Trace[I] = (*Depot)[RingPos + I];
|
|
};
|
|
|
|
size_t NextErrorReport = 0;
|
|
|
|
// First, check for UAF.
|
|
{
|
|
uptr ChunkAddr;
|
|
Chunk::UnpackedHeader Header;
|
|
const u32 *Data;
|
|
uint8_t Tag;
|
|
if (ReadBlock(Info.BlockBegin, &ChunkAddr, &Header, &Data, &Tag) &&
|
|
Header.State != Chunk::State::Allocated &&
|
|
Data[MemTagPrevTagIndex] == FaultAddrTag) {
|
|
auto *R = &ErrorInfo->reports[NextErrorReport++];
|
|
R->error_type = USE_AFTER_FREE;
|
|
R->allocation_address = ChunkAddr;
|
|
R->allocation_size = Header.SizeOrUnusedBytes;
|
|
MaybeCollectTrace(R->allocation_trace,
|
|
Data[MemTagAllocationTraceIndex]);
|
|
R->allocation_tid = Data[MemTagAllocationTidIndex];
|
|
MaybeCollectTrace(R->deallocation_trace,
|
|
Data[MemTagDeallocationTraceIndex]);
|
|
R->deallocation_tid = Data[MemTagDeallocationTidIndex];
|
|
}
|
|
}
|
|
|
|
auto CheckOOB = [&](uptr BlockAddr) {
|
|
if (BlockAddr < Info.RegionBegin || BlockAddr >= Info.RegionEnd)
|
|
return false;
|
|
|
|
uptr ChunkAddr;
|
|
Chunk::UnpackedHeader Header;
|
|
const u32 *Data;
|
|
uint8_t Tag;
|
|
if (!ReadBlock(BlockAddr, &ChunkAddr, &Header, &Data, &Tag) ||
|
|
Header.State != Chunk::State::Allocated || Tag != FaultAddrTag)
|
|
return false;
|
|
|
|
auto *R = &ErrorInfo->reports[NextErrorReport++];
|
|
R->error_type =
|
|
UntaggedFaultAddr < ChunkAddr ? BUFFER_UNDERFLOW : BUFFER_OVERFLOW;
|
|
R->allocation_address = ChunkAddr;
|
|
R->allocation_size = Header.SizeOrUnusedBytes;
|
|
MaybeCollectTrace(R->allocation_trace, Data[MemTagAllocationTraceIndex]);
|
|
R->allocation_tid = Data[MemTagAllocationTidIndex];
|
|
return NextErrorReport ==
|
|
sizeof(ErrorInfo->reports) / sizeof(ErrorInfo->reports[0]);
|
|
};
|
|
|
|
if (CheckOOB(Info.BlockBegin))
|
|
return;
|
|
|
|
// Check for OOB in the 30 surrounding blocks. Beyond that we are likely to
|
|
// hit false positives.
|
|
for (int I = 1; I != 16; ++I)
|
|
if (CheckOOB(Info.BlockBegin + I * Info.BlockSize) ||
|
|
CheckOOB(Info.BlockBegin - I * Info.BlockSize))
|
|
return;
|
|
}
|
|
|
|
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;
|
|
|
|
// These are indexes into an "array" of 32-bit values that store information
|
|
// inline with a chunk that is relevant to diagnosing memory tag faults, where
|
|
// 0 corresponds to the address of the user memory. This means that negative
|
|
// indexes may be used to store information about allocations, while positive
|
|
// indexes may only be used to store information about deallocations, because
|
|
// the user memory is in use until it has been deallocated. The smallest index
|
|
// that may be used is -2, which corresponds to 8 bytes before the user
|
|
// memory, because the chunk header size is 8 bytes and in allocators that
|
|
// support memory tagging the minimum alignment is at least the tag granule
|
|
// size (16 on aarch64), and the largest index that may be used is 3 because
|
|
// we are only guaranteed to have at least a granule's worth of space in the
|
|
// user memory.
|
|
static const sptr MemTagAllocationTraceIndex = -2;
|
|
static const sptr MemTagAllocationTidIndex = -1;
|
|
static const sptr MemTagDeallocationTraceIndex = 0;
|
|
static const sptr MemTagDeallocationTidIndex = 1;
|
|
static const sptr MemTagPrevTagIndex = 2;
|
|
|
|
static const uptr MaxTraceSize = 64;
|
|
|
|
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
|
|
u8 TrackAllocationStacks : 1;
|
|
u32 QuarantineMaxChunkSize; // quarantine_max_chunk_size
|
|
} Options;
|
|
|
|
#ifdef GWP_ASAN_HOOKS
|
|
gwp_asan::GuardedPoolAllocator GuardedAlloc;
|
|
#endif // GWP_ASAN_HOOKS
|
|
|
|
StackDepot Depot;
|
|
|
|
// 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())) {
|
|
u8 PrevTag = extractTag(loadTag(reinterpret_cast<uptr>(Ptr)));
|
|
uptr TaggedBegin, TaggedEnd;
|
|
setRandomTag(Ptr, Size, &TaggedBegin, &TaggedEnd);
|
|
storeDeallocationStackMaybe(Ptr, PrevTag);
|
|
}
|
|
// 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) {
|
|
*Chunk =
|
|
Block + getChunkOffsetFromBlock(reinterpret_cast<const char *>(Block));
|
|
return Chunk::isValid(Cookie, reinterpret_cast<void *>(*Chunk), Header);
|
|
}
|
|
|
|
static uptr getChunkOffsetFromBlock(const char *Block) {
|
|
u32 Offset = 0;
|
|
if (reinterpret_cast<const u32 *>(Block)[0] == BlockMarker)
|
|
Offset = reinterpret_cast<const u32 *>(Block)[1];
|
|
return Offset + Chunk::getHeaderSize();
|
|
}
|
|
|
|
void storeAllocationStackMaybe(void *Ptr) {
|
|
if (!UNLIKELY(Options.TrackAllocationStacks))
|
|
return;
|
|
auto *Ptr32 = reinterpret_cast<u32 *>(Ptr);
|
|
Ptr32[MemTagAllocationTraceIndex] = collectStackTrace();
|
|
Ptr32[MemTagAllocationTidIndex] = getThreadID();
|
|
}
|
|
|
|
void storeDeallocationStackMaybe(void *Ptr, uint8_t PrevTag) {
|
|
if (!UNLIKELY(Options.TrackAllocationStacks))
|
|
return;
|
|
|
|
// Disable tag checks here so that we don't need to worry about zero sized
|
|
// allocations.
|
|
ScopedDisableMemoryTagChecks x;
|
|
auto *Ptr32 = reinterpret_cast<u32 *>(Ptr);
|
|
Ptr32[MemTagDeallocationTraceIndex] = collectStackTrace();
|
|
Ptr32[MemTagDeallocationTidIndex] = getThreadID();
|
|
Ptr32[MemTagPrevTagIndex] = PrevTag;
|
|
}
|
|
|
|
uptr getStats(ScopedString *Str) {
|
|
Primary.getStats(Str);
|
|
Secondary.getStats(Str);
|
|
Quarantine.getStats(Str);
|
|
return Str->length();
|
|
}
|
|
};
|
|
|
|
} // namespace scudo
|
|
|
|
#endif // SCUDO_COMBINED_H_
|