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/*
* Copyright (C) 2020-2021 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.
*/
#include "config.h"
#include <wtf/WTFConfig.h>
#include <wtf/Gigacage.h>
#include <wtf/Lock.h>
#include <wtf/StdLibExtras.h>
#if PLATFORM(COCOA)
#include <wtf/spi/cocoa/MachVMSPI.h>
#include <mach/mach.h>
#elif OS(LINUX)
#include <sys/mman.h>
#endif
#include <mutex>
#if ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
namespace WebConfig {
alignas(WTF::ConfigAlignment) Slot g_config[WTF::ConfigSizeToProtect / sizeof(Slot)];
} // namespace WebConfig
#else // not ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
namespace WTF {
Config g_wtfConfig;
} // namespace WTF
#endif // ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
namespace WTF {
#if ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
void setPermissionsOfConfigPage()
{
#if PLATFORM(COCOA)
static std::once_flag onceFlag;
std::call_once(onceFlag, [] {
mach_vm_address_t addr = bitwise_cast<uintptr_t>(static_cast<void*>(WebConfig::g_config));
auto flags = VM_FLAGS_FIXED | VM_FLAGS_OVERWRITE;
#if HAVE(VM_FLAGS_PERMANENT)
flags |= VM_FLAGS_PERMANENT;
#endif
auto attemptVMMapping = [&] {
return mach_vm_map(mach_task_self(), &addr, ConfigSizeToProtect, pageSize() - 1, flags, MEMORY_OBJECT_NULL, 0, false, VM_PROT_READ | VM_PROT_WRITE, VM_PROT_READ | VM_PROT_WRITE, VM_INHERIT_DEFAULT);
};
auto result = attemptVMMapping();
#if HAVE(VM_FLAGS_PERMANENT)
if (result != KERN_SUCCESS) {
flags &= ~VM_FLAGS_PERMANENT;
result = attemptVMMapping();
}
#endif
RELEASE_ASSERT(result == KERN_SUCCESS);
});
#endif // PLATFORM(COCOA)
}
#endif // ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
void Config::permanentlyFreeze()
{
static Lock configLock;
Locker locker { configLock };
RELEASE_ASSERT(roundUpToMultipleOf(pageSize(), ConfigSizeToProtect) == ConfigSizeToProtect);
if (!g_wtfConfig.isPermanentlyFrozen) {
g_wtfConfig.isPermanentlyFrozen = true;
#if GIGACAGE_ENABLED
g_gigacageConfig.isPermanentlyFrozen = true;
#endif
}
int result = 0;
#if ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
#if PLATFORM(COCOA)
enum {
AllowPermissionChangesAfterThis = false,
DisallowPermissionChangesAfterThis = true
};
// There's no going back now!
result = vm_protect(mach_task_self(), reinterpret_cast<vm_address_t>(&WebConfig::g_config), ConfigSizeToProtect, DisallowPermissionChangesAfterThis, VM_PROT_READ);
#elif OS(LINUX)
result = mprotect(&WebConfig::g_config, ConfigSizeToProtect, PROT_READ);
#elif OS(WINDOWS)
// FIXME: Implement equivalent, maybe with VirtualProtect.
// Also need to fix WebKitTestRunner.
// Note: the Windows port also currently does not support a unified Config
// record, which is needed for the current form of the freezing feature to
// work. See comments in PlatformEnable.h for UNIFIED_AND_FREEZABLE_CONFIG_RECORD.
#endif
#endif // ENABLE(UNIFIED_AND_FREEZABLE_CONFIG_RECORD)
RELEASE_ASSERT(!result);
RELEASE_ASSERT(g_wtfConfig.isPermanentlyFrozen);
}
} // namespace WTF
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