aboutsummaryrefslogtreecommitdiffstats
path: root/tun/wintun/memmod/memmod_windows.go
diff options
context:
space:
mode:
Diffstat (limited to 'tun/wintun/memmod/memmod_windows.go')
-rw-r--r--tun/wintun/memmod/memmod_windows.go620
1 files changed, 620 insertions, 0 deletions
diff --git a/tun/wintun/memmod/memmod_windows.go b/tun/wintun/memmod/memmod_windows.go
new file mode 100644
index 0000000..a168c4d
--- /dev/null
+++ b/tun/wintun/memmod/memmod_windows.go
@@ -0,0 +1,620 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2020 WireGuard LLC. All Rights Reserved.
+ */
+
+package memmod
+
+import (
+ "errors"
+ "fmt"
+ "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, old_headers *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 := old_headers.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: %v", 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))
+ var dst []byte
+ unsafeSlice(unsafe.Pointer(&dst), a2p(dest), int(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: %v", 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: %v", err)
+ }
+
+ return nil
+}
+
+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])
+ 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])
+ // 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: %v", 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: %v", 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)
+
+ var relInfos []uint16
+ unsafeSlice(
+ unsafe.Pointer(&relInfos),
+ a2p(uintptr(unsafe.Pointer(relocationHdr))+unsafe.Sizeof(*relocationHdr)),
+ int((uintptr(relocationHdr.SizeOfBlock)-unsafe.Sizeof(*relocationHdr))/unsafe.Sizeof(relInfos[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 !isBadReadPtr(uintptr(unsafe.Pointer(importDesc)), unsafe.Sizeof(*importDesc)) && importDesc.Name != 0 {
+ handle, err := loadLibraryA((*byte)(a2p(module.codeBase + uintptr(importDesc.Name))))
+ if err != nil {
+ return fmt.Errorf("Error loading module: %v", 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 = getProcAddress(handle, (*byte)(a2p(IMAGE_ORDINAL(*thunkRef))))
+ } else {
+ thunkData := (*IMAGE_IMPORT_BY_NAME)(a2p(module.codeBase + *thunkRef))
+ *funcRef, err = getProcAddress(handle, &thunkData.Name[0])
+ }
+ if err != nil {
+ windows.FreeLibrary(handle)
+ return fmt.Errorf("Error getting function address: %v", 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")
+ }
+ var nameRefs []uint32
+ unsafeSlice(unsafe.Pointer(&nameRefs), a2p(module.codeBase+uintptr(exports.AddressOfNames)), int(exports.NumberOfNames))
+ var ordinals []uint16
+ unsafeSlice(unsafe.Pointer(&ordinals), a2p(module.codeBase+uintptr(exports.AddressOfNameOrdinals)), int(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
+}
+
+// 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: %v", err)
+ return
+ }
+ }
+ err = module.check4GBBoundaries(alignedImageSize)
+ if err != nil {
+ err = fmt.Errorf("Error reallocating code: %v", 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: %v", 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: %v", 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: %v", 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: %v", 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: %v", err)
+ 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) {
+ var d, s []byte
+ unsafeSlice(unsafe.Pointer(&d), a2p(dst), int(size))
+ unsafeSlice(unsafe.Pointer(&s), a2p(src), int(size))
+ copy(d, s)
+}
+
+// unsafeSlice updates the slice slicePtr to be a slice
+// referencing the provided data with its length & capacity set to
+// lenCap.
+//
+// TODO: when Go 1.16 or Go 1.17 is the minimum supported version,
+// update callers to use unsafe.Slice instead of this.
+func unsafeSlice(slicePtr, data unsafe.Pointer, lenCap int) {
+ type sliceHeader struct {
+ Data unsafe.Pointer
+ Len int
+ Cap int
+ }
+ h := (*sliceHeader)(slicePtr)
+ h.Data = data
+ h.Len = lenCap
+ h.Cap = lenCap
+}