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/*
* Copyright (C) 2020-2023 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <wtf/Compiler.h>
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN
#include <wtf/Assertions.h>
#include <wtf/Atomics.h>
#include <wtf/ExportMacros.h>
#include <wtf/PageBlock.h>
#include <wtf/PtrTag.h>
#include <wtf/StdLibExtras.h>
#include <wtf/threads/Signals.h>
#if USE(SYSTEM_MALLOC)
namespace Gigacage {
// The first 4 slots are reserved for the use of the ExecutableAllocator and additionalReservedSlots.
constexpr size_t reservedSlotsForGigacageConfig = 4;
constexpr size_t reservedBytesForGigacageConfig = reservedSlotsForGigacageConfig * sizeof(uint64_t);
}
#else
#include <bmalloc/GigacageConfig.h>
#endif
namespace WebConfig {
using Slot = uint64_t;
extern "C" WTF_EXPORT_PRIVATE Slot g_config[];
constexpr size_t reservedSlotsForExecutableAllocator = 2;
constexpr size_t additionalReservedSlots = 2;
enum ReservedConfigByteOffset {
ReservedByteForAllocationProfiling,
ReservedByteForAllocationProfilingMode,
NumberOfReservedConfigBytes
};
static_assert(NumberOfReservedConfigBytes <= sizeof(Slot) * additionalReservedSlots);
} // namespace WebConfig
namespace WTF {
constexpr size_t ConfigAlignment = CeilingOnPageSize;
constexpr size_t ConfigSizeToProtect = std::max(CeilingOnPageSize, 16 * KB);
struct Config {
WTF_EXPORT_PRIVATE static void permanentlyFreeze();
WTF_EXPORT_PRIVATE static void initialize();
WTF_EXPORT_PRIVATE static void finalize();
WTF_EXPORT_PRIVATE static void disableFreezingForTesting();
struct AssertNotFrozenScope {
AssertNotFrozenScope();
~AssertNotFrozenScope();
};
// All the fields in this struct should be chosen such that their
// initial value is 0 / null / falsy because Config is instantiated
// as a global singleton.
uintptr_t lowestAccessibleAddress;
uintptr_t highestAccessibleAddress;
bool isPermanentlyFrozen;
bool disabledFreezingForTesting;
bool useSpecialAbortForExtraSecurityImplications;
#if PLATFORM(COCOA)
bool disableForwardingVPrintfStdErrToOSLog;
#endif
#if USE(PTHREADS)
bool isUserSpecifiedThreadSuspendResumeSignalConfigured;
bool isThreadSuspendResumeSignalConfigured;
int sigThreadSuspendResume;
#endif
SignalHandlers signalHandlers;
PtrTagLookup* ptrTagLookupHead;
uint64_t spaceForExtensions[1];
};
constexpr size_t startSlotOfWTFConfig = Gigacage::reservedSlotsForGigacageConfig;
constexpr size_t startOffsetOfWTFConfig = startSlotOfWTFConfig * sizeof(WebConfig::Slot);
constexpr size_t offsetOfWTFConfigExtension = startOffsetOfWTFConfig + offsetof(WTF::Config, spaceForExtensions);
constexpr size_t alignmentOfWTFConfig = std::alignment_of<WTF::Config>::value;
static_assert(Gigacage::reservedBytesForGigacageConfig + sizeof(WTF::Config) <= ConfigSizeToProtect);
static_assert(roundUpToMultipleOf<alignmentOfWTFConfig>(startOffsetOfWTFConfig) == startOffsetOfWTFConfig);
WTF_EXPORT_PRIVATE void setPermissionsOfConfigPage();
// Workaround to localize bounds safety warnings to this file.
// FIXME: Use real types to make materializing WTF::Config* bounds-safe and type-safe.
inline Config* addressOfWTFConfig() { return std::bit_cast<Config*>(&WebConfig::g_config[startSlotOfWTFConfig]); }
#define g_wtfConfig (*WTF::addressOfWTFConfig())
constexpr size_t offsetOfWTFConfigLowestAccessibleAddress = offsetof(WTF::Config, lowestAccessibleAddress);
ALWAYS_INLINE Config::AssertNotFrozenScope::AssertNotFrozenScope()
{
RELEASE_ASSERT(!g_wtfConfig.isPermanentlyFrozen);
compilerFence();
};
ALWAYS_INLINE Config::AssertNotFrozenScope::~AssertNotFrozenScope()
{
compilerFence();
RELEASE_ASSERT(!g_wtfConfig.isPermanentlyFrozen);
};
} // namespace WTF
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
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