wintun: remove memmod option for dll loading

Only wireguard-windows used this, and it's moving to wgnt exclusively.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

1 files changed, 0 insertions, 693 deletions

diff --git a/tun/wintun/memmod/memmod_windows.go b/tun/wintun/memmod/memmod_windows.go
deleted file mode 100644
index da6ff9a..0000000
--- a/tun/wintun/memmod/memmod_windows.go
+++ /dev/null
@@ -1,693 +0,0 @@
-/* SPDX-License-Identifier: MIT
- *
- * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
- */
-
-package memmod
-
-import (
-	"errors"
-	"fmt"
-	"strings"
-	"sync"
-	"syscall"
-	"unsafe"
-
-	"golang.org/x/sys/windows"
-)
-
-type addressList struct {
-	next    *addressList
-	address uintptr
-}
-
-func (head *addressList) free() {
-	for node := head; node != nil; node = node.next {
-		windows.VirtualFree(node.address, 0, windows.MEM_RELEASE)
-	}
-}
-
-type Module struct {
-	headers       *IMAGE_NT_HEADERS
-	codeBase      uintptr
-	modules       []windows.Handle
-	initialized   bool
-	isDLL         bool
-	isRelocated   bool
-	nameExports   map[string]uint16
-	entry         uintptr
-	blockedMemory *addressList
-}
-
-func (module *Module) headerDirectory(idx int) *IMAGE_DATA_DIRECTORY {
-	return &module.headers.OptionalHeader.DataDirectory[idx]
-}
-
-func (module *Module) copySections(address uintptr, size uintptr, oldHeaders *IMAGE_NT_HEADERS) error {
-	sections := module.headers.Sections()
-	for i := range sections {
-		if sections[i].SizeOfRawData == 0 {
-			// Section doesn't contain data in the dll itself, but may define uninitialized data.
-			sectionSize := oldHeaders.OptionalHeader.SectionAlignment
-			if sectionSize == 0 {
-				continue
-			}
-			dest, err := windows.VirtualAlloc(module.codeBase+uintptr(sections[i].VirtualAddress),
-				uintptr(sectionSize),
-				windows.MEM_COMMIT,
-				windows.PAGE_READWRITE)
-			if err != nil {
-				return fmt.Errorf("Error allocating section: %w", err)
-			}
-
-			// Always use position from file to support alignments smaller than page size (allocation above will align to page size).
-			dest = module.codeBase + uintptr(sections[i].VirtualAddress)
-			// NOTE: On 64bit systems we truncate to 32bit here but expand again later when "PhysicalAddress" is used.
-			sections[i].SetPhysicalAddress((uint32)(dest & 0xffffffff))
-			dst := unsafe.Slice((*byte)(a2p(dest)), sectionSize)
-			for j := range dst {
-				dst[j] = 0
-			}
-			continue
-		}
-
-		if size < uintptr(sections[i].PointerToRawData+sections[i].SizeOfRawData) {
-			return errors.New("Incomplete section")
-		}
-
-		// Commit memory block and copy data from dll.
-		dest, err := windows.VirtualAlloc(module.codeBase+uintptr(sections[i].VirtualAddress),
-			uintptr(sections[i].SizeOfRawData),
-			windows.MEM_COMMIT,
-			windows.PAGE_READWRITE)
-		if err != nil {
-			return fmt.Errorf("Error allocating memory block: %w", err)
-		}
-
-		// Always use position from file to support alignments smaller than page size (allocation above will align to page size).
-		memcpy(
-			module.codeBase+uintptr(sections[i].VirtualAddress),
-			address+uintptr(sections[i].PointerToRawData),
-			uintptr(sections[i].SizeOfRawData))
-		// NOTE: On 64bit systems we truncate to 32bit here but expand again later when "PhysicalAddress" is used.
-		sections[i].SetPhysicalAddress((uint32)(dest & 0xffffffff))
-	}
-
-	return nil
-}
-
-func (module *Module) realSectionSize(section *IMAGE_SECTION_HEADER) uintptr {
-	size := section.SizeOfRawData
-	if size != 0 {
-		return uintptr(size)
-	}
-	if (section.Characteristics & IMAGE_SCN_CNT_INITIALIZED_DATA) != 0 {
-		return uintptr(module.headers.OptionalHeader.SizeOfInitializedData)
-	}
-	if (section.Characteristics & IMAGE_SCN_CNT_UNINITIALIZED_DATA) != 0 {
-		return uintptr(module.headers.OptionalHeader.SizeOfUninitializedData)
-	}
-	return 0
-}
-
-type sectionFinalizeData struct {
-	address         uintptr
-	alignedAddress  uintptr
-	size            uintptr
-	characteristics uint32
-	last            bool
-}
-
-func (module *Module) finalizeSection(sectionData *sectionFinalizeData) error {
-	if sectionData.size == 0 {
-		return nil
-	}
-
-	if (sectionData.characteristics & IMAGE_SCN_MEM_DISCARDABLE) != 0 {
-		// Section is not needed any more and can safely be freed.
-		if sectionData.address == sectionData.alignedAddress &&
-			(sectionData.last ||
-				(sectionData.size%uintptr(module.headers.OptionalHeader.SectionAlignment)) == 0) {
-			// Only allowed to decommit whole pages.
-			windows.VirtualFree(sectionData.address, sectionData.size, windows.MEM_DECOMMIT)
-		}
-		return nil
-	}
-
-	// determine protection flags based on characteristics
-	var ProtectionFlags = [8]uint32{
-		windows.PAGE_NOACCESS,          // not writeable, not readable, not executable
-		windows.PAGE_EXECUTE,           // not writeable, not readable, executable
-		windows.PAGE_READONLY,          // not writeable, readable, not executable
-		windows.PAGE_EXECUTE_READ,      // not writeable, readable, executable
-		windows.PAGE_WRITECOPY,         // writeable, not readable, not executable
-		windows.PAGE_EXECUTE_WRITECOPY, // writeable, not readable, executable
-		windows.PAGE_READWRITE,         // writeable, readable, not executable
-		windows.PAGE_EXECUTE_READWRITE, // writeable, readable, executable
-	}
-	protect := ProtectionFlags[sectionData.characteristics>>29]
-	if (sectionData.characteristics & IMAGE_SCN_MEM_NOT_CACHED) != 0 {
-		protect |= windows.PAGE_NOCACHE
-	}
-
-	// Change memory access flags.
-	var oldProtect uint32
-	err := windows.VirtualProtect(sectionData.address, sectionData.size, protect, &oldProtect)
-	if err != nil {
-		return fmt.Errorf("Error protecting memory page: %w", err)
-	}
-
-	return nil
-}
-
-var rtlAddFunctionTable = windows.NewLazySystemDLL("ntdll.dll").NewProc("RtlAddFunctionTable")
-
-func (module *Module) registerExceptionHandlers() {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXCEPTION)
-	if directory.Size == 0 || directory.VirtualAddress == 0 {
-		return
-	}
-	rtlAddFunctionTable.Call(module.codeBase+uintptr(directory.VirtualAddress), uintptr(directory.Size)/unsafe.Sizeof(IMAGE_RUNTIME_FUNCTION_ENTRY{}), module.codeBase)
-}
-
-func (module *Module) finalizeSections() error {
-	sections := module.headers.Sections()
-	imageOffset := module.headers.OptionalHeader.imageOffset()
-	sectionData := sectionFinalizeData{}
-	sectionData.address = uintptr(sections[0].PhysicalAddress()) | imageOffset
-	sectionData.alignedAddress = alignDown(sectionData.address, uintptr(module.headers.OptionalHeader.SectionAlignment))
-	sectionData.size = module.realSectionSize(&sections[0])
-	sections[0].SetVirtualSize(uint32(sectionData.size))
-	sectionData.characteristics = sections[0].Characteristics
-
-	// Loop through all sections and change access flags.
-	for i := uint16(1); i < module.headers.FileHeader.NumberOfSections; i++ {
-		sectionAddress := uintptr(sections[i].PhysicalAddress()) | imageOffset
-		alignedAddress := alignDown(sectionAddress, uintptr(module.headers.OptionalHeader.SectionAlignment))
-		sectionSize := module.realSectionSize(&sections[i])
-		sections[i].SetVirtualSize(uint32(sectionSize))
-		// Combine access flags of all sections that share a page.
-		// TODO: We currently share flags of a trailing large section with the page of a first small section. This should be optimized.
-		if sectionData.alignedAddress == alignedAddress || sectionData.address+sectionData.size > alignedAddress {
-			// Section shares page with previous.
-			if (sections[i].Characteristics&IMAGE_SCN_MEM_DISCARDABLE) == 0 || (sectionData.characteristics&IMAGE_SCN_MEM_DISCARDABLE) == 0 {
-				sectionData.characteristics = (sectionData.characteristics | sections[i].Characteristics) &^ IMAGE_SCN_MEM_DISCARDABLE
-			} else {
-				sectionData.characteristics |= sections[i].Characteristics
-			}
-			sectionData.size = sectionAddress + sectionSize - sectionData.address
-			continue
-		}
-
-		err := module.finalizeSection(&sectionData)
-		if err != nil {
-			return fmt.Errorf("Error finalizing section: %w", err)
-		}
-		sectionData.address = sectionAddress
-		sectionData.alignedAddress = alignedAddress
-		sectionData.size = sectionSize
-		sectionData.characteristics = sections[i].Characteristics
-	}
-	sectionData.last = true
-	err := module.finalizeSection(&sectionData)
-	if err != nil {
-		return fmt.Errorf("Error finalizing section: %w", err)
-	}
-	return nil
-}
-
-func (module *Module) executeTLS() {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_TLS)
-	if directory.VirtualAddress == 0 {
-		return
-	}
-
-	tls := (*IMAGE_TLS_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
-	callback := tls.AddressOfCallbacks
-	if callback != 0 {
-		for {
-			f := *(*uintptr)(a2p(callback))
-			if f == 0 {
-				break
-			}
-			syscall.Syscall(f, 3, module.codeBase, uintptr(DLL_PROCESS_ATTACH), uintptr(0))
-			callback += unsafe.Sizeof(f)
-		}
-	}
-}
-
-func (module *Module) performBaseRelocation(delta uintptr) (relocated bool, err error) {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_BASERELOC)
-	if directory.Size == 0 {
-		return delta == 0, nil
-	}
-
-	relocationHdr := (*IMAGE_BASE_RELOCATION)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
-	for relocationHdr.VirtualAddress > 0 {
-		dest := module.codeBase + uintptr(relocationHdr.VirtualAddress)
-
-		relInfos := unsafe.Slice(
-			(*uint16)(a2p(uintptr(unsafe.Pointer(relocationHdr))+unsafe.Sizeof(*relocationHdr))),
-			(uintptr(relocationHdr.SizeOfBlock)-unsafe.Sizeof(*relocationHdr))/unsafe.Sizeof(uint16(0)))
-		for _, relInfo := range relInfos {
-			// The upper 4 bits define the type of relocation.
-			relType := relInfo >> 12
-			// The lower 12 bits define the offset.
-			relOffset := uintptr(relInfo & 0xfff)
-
-			switch relType {
-			case IMAGE_REL_BASED_ABSOLUTE:
-				// Skip relocation.
-
-			case IMAGE_REL_BASED_LOW:
-				*(*uint16)(a2p(dest + relOffset)) += uint16(delta & 0xffff)
-				break
-
-			case IMAGE_REL_BASED_HIGH:
-				*(*uint16)(a2p(dest + relOffset)) += uint16(uint32(delta) >> 16)
-				break
-
-			case IMAGE_REL_BASED_HIGHLOW:
-				*(*uint32)(a2p(dest + relOffset)) += uint32(delta)
-
-			case IMAGE_REL_BASED_DIR64:
-				*(*uint64)(a2p(dest + relOffset)) += uint64(delta)
-
-			case IMAGE_REL_BASED_THUMB_MOV32:
-				inst := *(*uint32)(a2p(dest + relOffset))
-				imm16 := ((inst << 1) & 0x0800) + ((inst << 12) & 0xf000) +
-					((inst >> 20) & 0x0700) + ((inst >> 16) & 0x00ff)
-				if (inst & 0x8000fbf0) != 0x0000f240 {
-					return false, fmt.Errorf("Wrong Thumb2 instruction %08x, expected MOVW", inst)
-				}
-				imm16 += uint32(delta) & 0xffff
-				hiDelta := (uint32(delta&0xffff0000) >> 16) + ((imm16 & 0xffff0000) >> 16)
-				*(*uint32)(a2p(dest + relOffset)) = (inst & 0x8f00fbf0) + ((imm16 >> 1) & 0x0400) +
-					((imm16 >> 12) & 0x000f) +
-					((imm16 << 20) & 0x70000000) +
-					((imm16 << 16) & 0xff0000)
-				if hiDelta != 0 {
-					inst = *(*uint32)(a2p(dest + relOffset + 4))
-					imm16 = ((inst << 1) & 0x0800) + ((inst << 12) & 0xf000) +
-						((inst >> 20) & 0x0700) + ((inst >> 16) & 0x00ff)
-					if (inst & 0x8000fbf0) != 0x0000f2c0 {
-						return false, fmt.Errorf("Wrong Thumb2 instruction %08x, expected MOVT", inst)
-					}
-					imm16 += hiDelta
-					if imm16 > 0xffff {
-						return false, fmt.Errorf("Resulting immediate value won't fit: %08x", imm16)
-					}
-					*(*uint32)(a2p(dest + relOffset + 4)) = (inst & 0x8f00fbf0) +
-						((imm16 >> 1) & 0x0400) +
-						((imm16 >> 12) & 0x000f) +
-						((imm16 << 20) & 0x70000000) +
-						((imm16 << 16) & 0xff0000)
-				}
-
-			default:
-				return false, fmt.Errorf("Unsupported relocation: %v", relType)
-			}
-		}
-
-		// Advance to next relocation block.
-		relocationHdr = (*IMAGE_BASE_RELOCATION)(a2p(uintptr(unsafe.Pointer(relocationHdr)) + uintptr(relocationHdr.SizeOfBlock)))
-	}
-	return true, nil
-}
-
-func (module *Module) buildImportTable() error {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_IMPORT)
-	if directory.Size == 0 {
-		return nil
-	}
-
-	module.modules = make([]windows.Handle, 0, 16)
-	importDesc := (*IMAGE_IMPORT_DESCRIPTOR)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
-	for importDesc.Name != 0 {
-		handle, err := windows.LoadLibraryEx(windows.BytePtrToString((*byte)(a2p(module.codeBase+uintptr(importDesc.Name)))), 0, windows.LOAD_LIBRARY_SEARCH_SYSTEM32)
-		if err != nil {
-			return fmt.Errorf("Error loading module: %w", err)
-		}
-		var thunkRef, funcRef *uintptr
-		if importDesc.OriginalFirstThunk() != 0 {
-			thunkRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.OriginalFirstThunk())))
-			funcRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
-		} else {
-			// No hint table.
-			thunkRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
-			funcRef = (*uintptr)(a2p(module.codeBase + uintptr(importDesc.FirstThunk)))
-		}
-		for *thunkRef != 0 {
-			if IMAGE_SNAP_BY_ORDINAL(*thunkRef) {
-				*funcRef, err = windows.GetProcAddressByOrdinal(handle, IMAGE_ORDINAL(*thunkRef))
-			} else {
-				thunkData := (*IMAGE_IMPORT_BY_NAME)(a2p(module.codeBase + *thunkRef))
-				*funcRef, err = windows.GetProcAddress(handle, windows.BytePtrToString(&thunkData.Name[0]))
-			}
-			if err != nil {
-				windows.FreeLibrary(handle)
-				return fmt.Errorf("Error getting function address: %w", err)
-			}
-			thunkRef = (*uintptr)(a2p(uintptr(unsafe.Pointer(thunkRef)) + unsafe.Sizeof(*thunkRef)))
-			funcRef = (*uintptr)(a2p(uintptr(unsafe.Pointer(funcRef)) + unsafe.Sizeof(*funcRef)))
-		}
-		module.modules = append(module.modules, handle)
-		importDesc = (*IMAGE_IMPORT_DESCRIPTOR)(a2p(uintptr(unsafe.Pointer(importDesc)) + unsafe.Sizeof(*importDesc)))
-	}
-	return nil
-}
-
-func (module *Module) buildNameExports() error {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
-	if directory.Size == 0 {
-		return errors.New("No export table found")
-	}
-	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
-	if exports.NumberOfNames == 0 || exports.NumberOfFunctions == 0 {
-		return errors.New("No functions exported")
-	}
-	if exports.NumberOfNames == 0 {
-		return errors.New("No functions exported by name")
-	}
-	nameRefs := unsafe.Slice((*uint32)(a2p(module.codeBase+uintptr(exports.AddressOfNames))), exports.NumberOfNames)
-	ordinals := unsafe.Slice((*uint16)(a2p(module.codeBase+uintptr(exports.AddressOfNameOrdinals))), exports.NumberOfNames)
-	module.nameExports = make(map[string]uint16)
-	for i := range nameRefs {
-		nameArray := windows.BytePtrToString((*byte)(a2p(module.codeBase + uintptr(nameRefs[i]))))
-		module.nameExports[nameArray] = ordinals[i]
-	}
-	return nil
-}
-
-type addressRange struct {
-	start uintptr
-	end   uintptr
-}
-
-var loadedAddressRanges []addressRange
-var loadedAddressRangesMu sync.RWMutex
-var haveHookedRtlPcToFileHeader sync.Once
-var hookRtlPcToFileHeaderResult error
-
-func hookRtlPcToFileHeader() error {
-	var kernelBase windows.Handle
-	err := windows.GetModuleHandleEx(windows.GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, windows.StringToUTF16Ptr("kernelbase.dll"), &kernelBase)
-	if err != nil {
-		return err
-	}
-	imageBase := unsafe.Pointer(kernelBase)
-	dosHeader := (*IMAGE_DOS_HEADER)(imageBase)
-	ntHeaders := (*IMAGE_NT_HEADERS)(unsafe.Add(imageBase, dosHeader.E_lfanew))
-	importsDirectory := ntHeaders.OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT]
-	importDescriptor := (*IMAGE_IMPORT_DESCRIPTOR)(unsafe.Add(imageBase, importsDirectory.VirtualAddress))
-	for ; importDescriptor.Name != 0; importDescriptor = (*IMAGE_IMPORT_DESCRIPTOR)(unsafe.Add(unsafe.Pointer(importDescriptor), unsafe.Sizeof(*importDescriptor))) {
-		libraryName := windows.BytePtrToString((*byte)(unsafe.Add(imageBase, importDescriptor.Name)))
-		if strings.EqualFold(libraryName, "ntdll.dll") {
-			break
-		}
-	}
-	if importDescriptor.Name == 0 {
-		return errors.New("ntdll.dll not found")
-	}
-	originalThunk := (*uintptr)(unsafe.Add(imageBase, importDescriptor.OriginalFirstThunk()))
-	thunk := (*uintptr)(unsafe.Add(imageBase, importDescriptor.FirstThunk))
-	for ; *originalThunk != 0; originalThunk = (*uintptr)(unsafe.Add(unsafe.Pointer(originalThunk), unsafe.Sizeof(*originalThunk))) {
-		if *originalThunk&IMAGE_ORDINAL_FLAG == 0 {
-			function := (*IMAGE_IMPORT_BY_NAME)(unsafe.Add(imageBase, *originalThunk))
-			name := windows.BytePtrToString(&function.Name[0])
-			if name == "RtlPcToFileHeader" {
-				break
-			}
-		}
-		thunk = (*uintptr)(unsafe.Add(unsafe.Pointer(thunk), unsafe.Sizeof(*thunk)))
-	}
-	if *originalThunk == 0 {
-		return errors.New("RtlPcToFileHeader not found")
-	}
-	var oldProtect uint32
-	err = windows.VirtualProtect(uintptr(unsafe.Pointer(thunk)), unsafe.Sizeof(*thunk), windows.PAGE_READWRITE, &oldProtect)
-	if err != nil {
-		return err
-	}
-	originalRtlPcToFileHeader := *thunk
-	*thunk = windows.NewCallback(func(pcValue uintptr, baseOfImage *uintptr) uintptr {
-		loadedAddressRangesMu.RLock()
-		for i := range loadedAddressRanges {
-			if pcValue >= loadedAddressRanges[i].start && pcValue < loadedAddressRanges[i].end {
-				pcValue = *thunk
-				break
-			}
-		}
-		loadedAddressRangesMu.RUnlock()
-		ret, _, _ := syscall.Syscall(originalRtlPcToFileHeader, 2, pcValue, uintptr(unsafe.Pointer(baseOfImage)), 0)
-		return ret
-	})
-	err = windows.VirtualProtect(uintptr(unsafe.Pointer(thunk)), unsafe.Sizeof(*thunk), oldProtect, &oldProtect)
-	if err != nil {
-		return err
-	}
-	return nil
-}
-
-// LoadLibrary loads module image to memory.
-func LoadLibrary(data []byte) (module *Module, err error) {
-	addr := uintptr(unsafe.Pointer(&data[0]))
-	size := uintptr(len(data))
-	if size < unsafe.Sizeof(IMAGE_DOS_HEADER{}) {
-		return nil, errors.New("Incomplete IMAGE_DOS_HEADER")
-	}
-	dosHeader := (*IMAGE_DOS_HEADER)(a2p(addr))
-	if dosHeader.E_magic != IMAGE_DOS_SIGNATURE {
-		return nil, fmt.Errorf("Not an MS-DOS binary (provided: %x, expected: %x)", dosHeader.E_magic, IMAGE_DOS_SIGNATURE)
-	}
-	if (size < uintptr(dosHeader.E_lfanew)+unsafe.Sizeof(IMAGE_NT_HEADERS{})) {
-		return nil, errors.New("Incomplete IMAGE_NT_HEADERS")
-	}
-	oldHeader := (*IMAGE_NT_HEADERS)(a2p(addr + uintptr(dosHeader.E_lfanew)))
-	if oldHeader.Signature != IMAGE_NT_SIGNATURE {
-		return nil, fmt.Errorf("Not an NT binary (provided: %x, expected: %x)", oldHeader.Signature, IMAGE_NT_SIGNATURE)
-	}
-	if oldHeader.FileHeader.Machine != imageFileProcess {
-		return nil, fmt.Errorf("Foreign platform (provided: %x, expected: %x)", oldHeader.FileHeader.Machine, imageFileProcess)
-	}
-	if (oldHeader.OptionalHeader.SectionAlignment & 1) != 0 {
-		return nil, errors.New("Unaligned section")
-	}
-	lastSectionEnd := uintptr(0)
-	sections := oldHeader.Sections()
-	optionalSectionSize := oldHeader.OptionalHeader.SectionAlignment
-	for i := range sections {
-		var endOfSection uintptr
-		if sections[i].SizeOfRawData == 0 {
-			// Section without data in the DLL
-			endOfSection = uintptr(sections[i].VirtualAddress) + uintptr(optionalSectionSize)
-		} else {
-			endOfSection = uintptr(sections[i].VirtualAddress) + uintptr(sections[i].SizeOfRawData)
-		}
-		if endOfSection > lastSectionEnd {
-			lastSectionEnd = endOfSection
-		}
-	}
-	alignedImageSize := alignUp(uintptr(oldHeader.OptionalHeader.SizeOfImage), uintptr(oldHeader.OptionalHeader.SectionAlignment))
-	if alignedImageSize != alignUp(lastSectionEnd, uintptr(oldHeader.OptionalHeader.SectionAlignment)) {
-		return nil, errors.New("Section is not page-aligned")
-	}
-
-	module = &Module{isDLL: (oldHeader.FileHeader.Characteristics & IMAGE_FILE_DLL) != 0}
-	defer func() {
-		if err != nil {
-			module.Free()
-			module = nil
-		}
-	}()
-
-	// Reserve memory for image of library.
-	// TODO: Is it correct to commit the complete memory region at once? Calling DllEntry raises an exception if we don't.
-	module.codeBase, err = windows.VirtualAlloc(oldHeader.OptionalHeader.ImageBase,
-		alignedImageSize,
-		windows.MEM_RESERVE|windows.MEM_COMMIT,
-		windows.PAGE_READWRITE)
-	if err != nil {
-		// Try to allocate memory at arbitrary position.
-		module.codeBase, err = windows.VirtualAlloc(0,
-			alignedImageSize,
-			windows.MEM_RESERVE|windows.MEM_COMMIT,
-			windows.PAGE_READWRITE)
-		if err != nil {
-			err = fmt.Errorf("Error allocating code: %w", err)
-			return
-		}
-	}
-	err = module.check4GBBoundaries(alignedImageSize)
-	if err != nil {
-		err = fmt.Errorf("Error reallocating code: %w", err)
-		return
-	}
-
-	if size < uintptr(oldHeader.OptionalHeader.SizeOfHeaders) {
-		err = errors.New("Incomplete headers")
-		return
-	}
-	// Commit memory for headers.
-	headers, err := windows.VirtualAlloc(module.codeBase,
-		uintptr(oldHeader.OptionalHeader.SizeOfHeaders),
-		windows.MEM_COMMIT,
-		windows.PAGE_READWRITE)
-	if err != nil {
-		err = fmt.Errorf("Error allocating headers: %w", err)
-		return
-	}
-	// Copy PE header to code.
-	memcpy(headers, addr, uintptr(oldHeader.OptionalHeader.SizeOfHeaders))
-	module.headers = (*IMAGE_NT_HEADERS)(a2p(headers + uintptr(dosHeader.E_lfanew)))
-
-	// Update position.
-	module.headers.OptionalHeader.ImageBase = module.codeBase
-
-	// Copy sections from DLL file block to new memory location.
-	err = module.copySections(addr, size, oldHeader)
-	if err != nil {
-		err = fmt.Errorf("Error copying sections: %w", err)
-		return
-	}
-
-	// Adjust base address of imported data.
-	locationDelta := module.headers.OptionalHeader.ImageBase - oldHeader.OptionalHeader.ImageBase
-	if locationDelta != 0 {
-		module.isRelocated, err = module.performBaseRelocation(locationDelta)
-		if err != nil {
-			err = fmt.Errorf("Error relocating module: %w", err)
-			return
-		}
-	} else {
-		module.isRelocated = true
-	}
-
-	// Load required dlls and adjust function table of imports.
-	err = module.buildImportTable()
-	if err != nil {
-		err = fmt.Errorf("Error building import table: %w", err)
-		return
-	}
-
-	// Mark memory pages depending on section headers and release sections that are marked as "discardable".
-	err = module.finalizeSections()
-	if err != nil {
-		err = fmt.Errorf("Error finalizing sections: %w", err)
-		return
-	}
-
-	// Register exception tables, if they exist.
-	module.registerExceptionHandlers()
-
-	// Register function PCs.
-	loadedAddressRangesMu.Lock()
-	loadedAddressRanges = append(loadedAddressRanges, addressRange{module.codeBase, module.codeBase + alignedImageSize})
-	loadedAddressRangesMu.Unlock()
-	haveHookedRtlPcToFileHeader.Do(func() {
-		hookRtlPcToFileHeaderResult = hookRtlPcToFileHeader()
-	})
-	err = hookRtlPcToFileHeaderResult
-	if err != nil {
-		return
-	}
-
-	// TLS callbacks are executed BEFORE the main loading.
-	module.executeTLS()
-
-	// Get entry point of loaded module.
-	if module.headers.OptionalHeader.AddressOfEntryPoint != 0 {
-		module.entry = module.codeBase + uintptr(module.headers.OptionalHeader.AddressOfEntryPoint)
-		if module.isDLL {
-			// Notify library about attaching to process.
-			r0, _, _ := syscall.Syscall(module.entry, 3, module.codeBase, uintptr(DLL_PROCESS_ATTACH), 0)
-			successful := r0 != 0
-			if !successful {
-				err = windows.ERROR_DLL_INIT_FAILED
-				return
-			}
-			module.initialized = true
-		}
-	}
-
-	module.buildNameExports()
-	return
-}
-
-// Free releases module resources and unloads it.
-func (module *Module) Free() {
-	if module.initialized {
-		// Notify library about detaching from process.
-		syscall.Syscall(module.entry, 3, module.codeBase, uintptr(DLL_PROCESS_DETACH), 0)
-		module.initialized = false
-	}
-	if module.modules != nil {
-		// Free previously opened libraries.
-		for _, handle := range module.modules {
-			windows.FreeLibrary(handle)
-		}
-		module.modules = nil
-	}
-	if module.codeBase != 0 {
-		windows.VirtualFree(module.codeBase, 0, windows.MEM_RELEASE)
-		module.codeBase = 0
-	}
-	if module.blockedMemory != nil {
-		module.blockedMemory.free()
-		module.blockedMemory = nil
-	}
-}
-
-// ProcAddressByName returns function address by exported name.
-func (module *Module) ProcAddressByName(name string) (uintptr, error) {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
-	if directory.Size == 0 {
-		return 0, errors.New("No export table found")
-	}
-	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
-	if module.nameExports == nil {
-		return 0, errors.New("No functions exported by name")
-	}
-	if idx, ok := module.nameExports[name]; ok {
-		if uint32(idx) > exports.NumberOfFunctions {
-			return 0, errors.New("Ordinal number too high")
-		}
-		// AddressOfFunctions contains the RVAs to the "real" functions.
-		return module.codeBase + uintptr(*(*uint32)(a2p(module.codeBase + uintptr(exports.AddressOfFunctions) + uintptr(idx)*4))), nil
-	}
-	return 0, errors.New("Function not found by name")
-}
-
-// ProcAddressByOrdinal returns function address by exported ordinal.
-func (module *Module) ProcAddressByOrdinal(ordinal uint16) (uintptr, error) {
-	directory := module.headerDirectory(IMAGE_DIRECTORY_ENTRY_EXPORT)
-	if directory.Size == 0 {
-		return 0, errors.New("No export table found")
-	}
-	exports := (*IMAGE_EXPORT_DIRECTORY)(a2p(module.codeBase + uintptr(directory.VirtualAddress)))
-	if uint32(ordinal) < exports.Base {
-		return 0, errors.New("Ordinal number too low")
-	}
-	idx := ordinal - uint16(exports.Base)
-	if uint32(idx) > exports.NumberOfFunctions {
-		return 0, errors.New("Ordinal number too high")
-	}
-	// AddressOfFunctions contains the RVAs to the "real" functions.
-	return module.codeBase + uintptr(*(*uint32)(a2p(module.codeBase + uintptr(exports.AddressOfFunctions) + uintptr(idx)*4))), nil
-}
-
-func alignDown(value, alignment uintptr) uintptr {
-	return value & ^(alignment - 1)
-}
-
-func alignUp(value, alignment uintptr) uintptr {
-	return (value + alignment - 1) & ^(alignment - 1)
-}
-
-func a2p(addr uintptr) unsafe.Pointer {
-	return unsafe.Pointer(addr)
-}
-
-func memcpy(dst, src, size uintptr) {
-	copy(unsafe.Slice((*byte)(a2p(dst)), size), unsafe.Slice((*byte)(a2p(src)), size))
-}