Revision control
++ // Copyright (C) 2016 The Qt Company Ltd.
++ // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
++ // Qt-Security score:significant
++
++ #include "qv4compilationunitmapper_p.h"
++
++ #include <private/qv4compileddata_p.h>
++
++ #include <QtCore/qdatetime.h>
++ #include <QtCore/qfileinfo.h>
++ #include <QtCore/qscopeguard.h>
++
++ #include <qt_windows.h>
++
++ QT_BEGIN_NAMESPACE
++
++ using namespace QV4;
++
++ CompiledData::Unit *CompilationUnitMapper::open(const QString &cacheFileName, const QDateTime &sourceTimeStamp, QString *errorString)
++ {
++ close();
++
++ // ### TODO: fix up file encoding/normalization/unc handling once QFileSystemEntry
++ // is exported from QtCore.
++ HANDLE handle =
++ CreateFile(reinterpret_cast<const wchar_t*>(cacheFileName.constData()),
++ GENERIC_READ | GENERIC_EXECUTE, FILE_SHARE_READ,
++ nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
++ nullptr);
++ if (handle == INVALID_HANDLE_VALUE) {
++ *errorString = qt_error_string(GetLastError());
++ return nullptr;
++ }
++
++ auto fileHandleCleanup = qScopeGuard([handle]{
++ CloseHandle(handle);
++ });
++
++ CompiledData::Unit header;
++ DWORD bytesRead;
++ if (!ReadFile(handle, reinterpret_cast<char *>(&header), sizeof(header), &bytesRead, nullptr)) {
++ *errorString = qt_error_string(GetLastError());
++ return nullptr;
++ }
++
++ if (bytesRead != sizeof(header)) {
++ *errorString = QStringLiteral("File too small for the header fields");
++ return nullptr;
++ }
++
++ if (!header.verifyHeader(sourceTimeStamp, errorString))
++ return nullptr;
++
++ // Data structure and qt version matched, so now we can access the rest of the file safely.
++
++ /* Error out early on file corruption. We assume we can read header.unitSize bytes
++ later (even before verifying the checksum), potentially causing out-of-bound
++ reads
++ Also, no need to wait until checksum verification if we know beforehand
++ that the cached unit is bogus
++ */
++ LARGE_INTEGER fileSize;
++ if (!GetFileSizeEx(handle, &fileSize)) {
++ *errorString = QStringLiteral("Could not determine file size");
++ return nullptr;
++ }
++ if (header.unitSize != fileSize.QuadPart) {
++ *errorString = QStringLiteral("Potential file corruption, file too small");
++ return nullptr;
++ }
++
++
++ HANDLE fileMappingHandle = CreateFileMapping(handle, 0, PAGE_READONLY, 0, 0, 0);
++ if (!fileMappingHandle) {
++ *errorString = qt_error_string(GetLastError());
++ return nullptr;
++ }
++
++ auto mappingCleanup = qScopeGuard([fileMappingHandle]{
++ CloseHandle(fileMappingHandle);
++ });
++
++ dataPtr = MapViewOfFile(fileMappingHandle, FILE_MAP_READ, 0, 0, 0);
++ if (!dataPtr) {
++ *errorString = qt_error_string(GetLastError());
++ return nullptr;
++ }
++
++ return reinterpret_cast<CompiledData::Unit*>(dataPtr);
++ }
++
++ void CompilationUnitMapper::close()
++ {
++ if (dataPtr != nullptr) {
++ // Do not unmap cache files that are built with the StaticData flag. That's the majority of
++ // them and it's necessary to benefit from the QString literal optimization. There might
++ // still be QString instances around that point into that memory area. The memory is backed
++ // on the disk, so the kernel is free to release the pages and all that remains is the
++ // address space allocation.
++ if (!(reinterpret_cast<CompiledData::Unit*>(dataPtr)->flags & CompiledData::Unit::StaticData))
++ UnmapViewOfFile(dataPtr);
++ }
++ dataPtr = nullptr;
++ }
++
++ QT_END_NAMESPACE