Merge pull request #4807 from zmanda/windows-extendedattribs

Back up and restore Extended Attributes on Windows NTFS

changelog/unreleased/pull-4807

@@ -0,0 +1,5 @@
+Enhancement: Back up and restore Extended Attributes on Windows NTFS
+
+Restic now backs up and restores Extended Attributes on Windows NTFS when backing up files and folders.
+
+https://github.com/restic/restic/pull/4807

internal/fs/ea_windows.go

@@ -0,0 +1,285 @@
+//go:build windows
+// +build windows
+
+package fs
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+// The code below was adapted from https://github.com/microsoft/go-winio under MIT license.
+
+// The MIT License (MIT)
+
+// Copyright (c) 2015 Microsoft
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// The code below was copied over from https://github.com/microsoft/go-winio/blob/main/ea.go under MIT license.
+
+type fileFullEaInformation struct {
+	NextEntryOffset uint32
+	Flags           uint8
+	NameLength      uint8
+	ValueLength     uint16
+}
+
+var (
+	fileFullEaInformationSize = binary.Size(&fileFullEaInformation{})
+
+	errInvalidEaBuffer = errors.New("invalid extended attribute buffer")
+	errEaNameTooLarge  = errors.New("extended attribute name too large")
+	errEaValueTooLarge = errors.New("extended attribute value too large")
+)
+
+// ExtendedAttribute represents a single Windows EA.
+type ExtendedAttribute struct {
+	Name  string
+	Value []byte
+	Flags uint8
+}
+
+func parseEa(b []byte) (ea ExtendedAttribute, nb []byte, err error) {
+	var info fileFullEaInformation
+	err = binary.Read(bytes.NewReader(b), binary.LittleEndian, &info)
+	if err != nil {
+		err = errInvalidEaBuffer
+		return ea, nb, err
+	}
+
+	nameOffset := fileFullEaInformationSize
+	nameLen := int(info.NameLength)
+	valueOffset := nameOffset + int(info.NameLength) + 1
+	valueLen := int(info.ValueLength)
+	nextOffset := int(info.NextEntryOffset)
+	if valueLen+valueOffset > len(b) || nextOffset < 0 || nextOffset > len(b) {
+		err = errInvalidEaBuffer
+		return ea, nb, err
+	}
+
+	ea.Name = string(b[nameOffset : nameOffset+nameLen])
+	ea.Value = b[valueOffset : valueOffset+valueLen]
+	ea.Flags = info.Flags
+	if info.NextEntryOffset != 0 {
+		nb = b[info.NextEntryOffset:]
+	}
+	return ea, nb, err
+}
+
+// DecodeExtendedAttributes decodes a list of EAs from a FILE_FULL_EA_INFORMATION
+// buffer retrieved from BackupRead, ZwQueryEaFile, etc.
+func DecodeExtendedAttributes(b []byte) (eas []ExtendedAttribute, err error) {
+	for len(b) != 0 {
+		ea, nb, err := parseEa(b)
+		if err != nil {
+			return nil, err
+		}
+
+		eas = append(eas, ea)
+		b = nb
+	}
+	return eas, err
+}
+
+func writeEa(buf *bytes.Buffer, ea *ExtendedAttribute, last bool) error {
+	if int(uint8(len(ea.Name))) != len(ea.Name) {
+		return errEaNameTooLarge
+	}
+	if int(uint16(len(ea.Value))) != len(ea.Value) {
+		return errEaValueTooLarge
+	}
+	entrySize := uint32(fileFullEaInformationSize + len(ea.Name) + 1 + len(ea.Value))
+	withPadding := (entrySize + 3) &^ 3
+	nextOffset := uint32(0)
+	if !last {
+		nextOffset = withPadding
+	}
+	info := fileFullEaInformation{
+		NextEntryOffset: nextOffset,
+		Flags:           ea.Flags,
+		NameLength:      uint8(len(ea.Name)),
+		ValueLength:     uint16(len(ea.Value)),
+	}
+
+	err := binary.Write(buf, binary.LittleEndian, &info)
+	if err != nil {
+		return err
+	}
+
+	_, err = buf.Write([]byte(ea.Name))
+	if err != nil {
+		return err
+	}
+
+	err = buf.WriteByte(0)
+	if err != nil {
+		return err
+	}
+
+	_, err = buf.Write(ea.Value)
+	if err != nil {
+		return err
+	}
+
+	_, err = buf.Write([]byte{0, 0, 0}[0 : withPadding-entrySize])
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// EncodeExtendedAttributes encodes a list of EAs into a FILE_FULL_EA_INFORMATION
+// buffer for use with BackupWrite, ZwSetEaFile, etc.
+func EncodeExtendedAttributes(eas []ExtendedAttribute) ([]byte, error) {
+	var buf bytes.Buffer
+	for i := range eas {
+		last := false
+		if i == len(eas)-1 {
+			last = true
+		}
+
+		err := writeEa(&buf, &eas[i], last)
+		if err != nil {
+			return nil, err
+		}
+	}
+	return buf.Bytes(), nil
+}
+
+// The code below was copied over from https://github.com/microsoft/go-winio/blob/main/pipe.go under MIT license.
+
+type ntStatus int32
+
+func (status ntStatus) Err() error {
+	if status >= 0 {
+		return nil
+	}
+	return rtlNtStatusToDosError(status)
+}
+
+// The code below was copied over from https://github.com/microsoft/go-winio/blob/main/zsyscall_windows.go under MIT license.
+
+// ioStatusBlock represents the IO_STATUS_BLOCK struct defined here:
+// https://docs.microsoft.com/en-us/windows-hardware/drivers/ddi/wdm/ns-wdm-_io_status_block
+type ioStatusBlock struct {
+	Status, Information uintptr
+}
+
+var (
+	modntdll                       = windows.NewLazySystemDLL("ntdll.dll")
+	procRtlNtStatusToDosErrorNoTeb = modntdll.NewProc("RtlNtStatusToDosErrorNoTeb")
+)
+
+func rtlNtStatusToDosError(status ntStatus) (winerr error) {
+	r0, _, _ := syscall.SyscallN(procRtlNtStatusToDosErrorNoTeb.Addr(), uintptr(status))
+	if r0 != 0 {
+		winerr = syscall.Errno(r0)
+	}
+	return
+}
+
+// The code below was adapted from https://github.com/ambarve/go-winio/blob/a7564fd482feb903f9562a135f1317fd3b480739/ea.go
+// under MIT license.
+
+var (
+	procNtQueryEaFile = modntdll.NewProc("NtQueryEaFile")
+	procNtSetEaFile   = modntdll.NewProc("NtSetEaFile")
+)
+
+const (
+	// STATUS_NO_EAS_ON_FILE is a constant value which indicates EAs were requested for the file but it has no EAs.
+	// Windows NTSTATUS value: STATUS_NO_EAS_ON_FILE=0xC0000052
+	STATUS_NO_EAS_ON_FILE = -1073741742
+)
+
+// GetFileEA retrieves the extended attributes for the file represented by `handle`. The
+// `handle` must have been opened with file access flag FILE_READ_EA (0x8).
+// The extended file attribute names in windows are case-insensitive and when fetching
+// the attributes the names are generally returned in UPPER case.
+func GetFileEA(handle windows.Handle) ([]ExtendedAttribute, error) {
+	// default buffer size to start with
+	bufLen := 1024
+	buf := make([]byte, bufLen)
+	var iosb ioStatusBlock
+	// keep increasing the buffer size until it is large enough
+	for {
+		status := getFileEA(handle, &iosb, &buf[0], uint32(bufLen), false, 0, 0, nil, true)
+
+		if status == STATUS_NO_EAS_ON_FILE {
+			//If status is -1073741742, no extended attributes were found
+			return nil, nil
+		}
+		err := status.Err()
+		if err != nil {
+			// convert ntstatus code to windows error
+			if err == windows.ERROR_INSUFFICIENT_BUFFER || err == windows.ERROR_MORE_DATA {
+				bufLen *= 2
+				buf = make([]byte, bufLen)
+				continue
+			}
+			return nil, fmt.Errorf("get file EA failed with: %w", err)
+		}
+		break
+	}
+	return DecodeExtendedAttributes(buf)
+}
+
+// SetFileEA sets the extended attributes for the file represented by `handle`.  The
+// handle must have been opened with the file access flag FILE_WRITE_EA(0x10).
+func SetFileEA(handle windows.Handle, attrs []ExtendedAttribute) error {
+	encodedEA, err := EncodeExtendedAttributes(attrs)
+	if err != nil {
+		return fmt.Errorf("failed to encoded extended attributes: %w", err)
+	}
+
+	var iosb ioStatusBlock
+
+	return setFileEA(handle, &iosb, &encodedEA[0], uint32(len(encodedEA))).Err()
+}
+
+// The code below was adapted from https://github.com/ambarve/go-winio/blob/a7564fd482feb903f9562a135f1317fd3b480739/zsyscall_windows.go
+// under MIT license.
+
+func getFileEA(handle windows.Handle, iosb *ioStatusBlock, buf *uint8, bufLen uint32, returnSingleEntry bool, eaList uintptr, eaListLen uint32, eaIndex *uint32, restartScan bool) (status ntStatus) {
+	var _p0 uint32
+	if returnSingleEntry {
+		_p0 = 1
+	}
+	var _p1 uint32
+	if restartScan {
+		_p1 = 1
+	}
+	r0, _, _ := syscall.SyscallN(procNtQueryEaFile.Addr(), uintptr(handle), uintptr(unsafe.Pointer(iosb)), uintptr(unsafe.Pointer(buf)), uintptr(bufLen), uintptr(_p0), uintptr(eaList), uintptr(eaListLen), uintptr(unsafe.Pointer(eaIndex)), uintptr(_p1))
+	status = ntStatus(r0)
+	return
+}
+
+func setFileEA(handle windows.Handle, iosb *ioStatusBlock, buf *uint8, bufLen uint32) (status ntStatus) {
+	r0, _, _ := syscall.SyscallN(procNtSetEaFile.Addr(), uintptr(handle), uintptr(unsafe.Pointer(iosb)), uintptr(unsafe.Pointer(buf)), uintptr(bufLen))
+	status = ntStatus(r0)
+	return
+}

internal/fs/ea_windows_test.go

@@ -0,0 +1,247 @@
+//go:build windows
+// +build windows
+
+package fs
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+	"os"
+	"path/filepath"
+	"reflect"
+	"syscall"
+	"testing"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+// The code below was adapted from github.com/Microsoft/go-winio under MIT license.
+
+// The MIT License (MIT)
+
+// Copyright (c) 2015 Microsoft
+
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+// The code below was adapted from https://github.com/ambarve/go-winio/blob/a7564fd482feb903f9562a135f1317fd3b480739/ea_test.go
+// under MIT license.
+
+var (
+	testEas = []ExtendedAttribute{
+		{Name: "foo", Value: []byte("bar")},
+		{Name: "fizz", Value: []byte("buzz")},
+	}
+
+	testEasEncoded = []byte{16, 0, 0, 0, 0, 3, 3, 0, 102, 111, 111, 0, 98, 97, 114, 0, 0,
+		0, 0, 0, 0, 4, 4, 0, 102, 105, 122, 122, 0, 98, 117, 122, 122, 0, 0, 0}
+	testEasNotPadded = testEasEncoded[0 : len(testEasEncoded)-3]
+	testEasTruncated = testEasEncoded[0:20]
+)
+
+func TestRoundTripEas(t *testing.T) {
+	b, err := EncodeExtendedAttributes(testEas)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(testEasEncoded, b) {
+		t.Fatalf("Encoded mismatch %v %v", testEasEncoded, b)
+	}
+	eas, err := DecodeExtendedAttributes(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(testEas, eas) {
+		t.Fatalf("mismatch %+v %+v", testEas, eas)
+	}
+}
+
+func TestEasDontNeedPaddingAtEnd(t *testing.T) {
+	eas, err := DecodeExtendedAttributes(testEasNotPadded)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(testEas, eas) {
+		t.Fatalf("mismatch %+v %+v", testEas, eas)
+	}
+}
+
+func TestTruncatedEasFailCorrectly(t *testing.T) {
+	_, err := DecodeExtendedAttributes(testEasTruncated)
+	if err == nil {
+		t.Fatal("expected error")
+	}
+}
+
+func TestNilEasEncodeAndDecodeAsNil(t *testing.T) {
+	b, err := EncodeExtendedAttributes(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(b) != 0 {
+		t.Fatal("expected empty")
+	}
+	eas, err := DecodeExtendedAttributes(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(eas) != 0 {
+		t.Fatal("expected empty")
+	}
+}
+
+// TestSetFileEa makes sure that the test buffer is actually parsable by NtSetEaFile.
+func TestSetFileEa(t *testing.T) {
+	f, err := os.CreateTemp("", "testea")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() {
+		err := os.Remove(f.Name())
+		if err != nil {
+			t.Logf("Error removing file %s: %v\n", f.Name(), err)
+		}
+		err = f.Close()
+		if err != nil {
+			t.Logf("Error closing file %s: %v\n", f.Name(), err)
+		}
+	}()
+	ntdll := syscall.MustLoadDLL("ntdll.dll")
+	ntSetEaFile := ntdll.MustFindProc("NtSetEaFile")
+	var iosb [2]uintptr
+	r, _, _ := ntSetEaFile.Call(f.Fd(),
+		uintptr(unsafe.Pointer(&iosb[0])),
+		uintptr(unsafe.Pointer(&testEasEncoded[0])),
+		uintptr(len(testEasEncoded)))
+	if r != 0 {
+		t.Fatalf("NtSetEaFile failed with %08x", r)
+	}
+}
+
+// The code below was refactored from github.com/Microsoft/go-winio/blob/a7564fd482feb903f9562a135f1317fd3b480739/ea_test.go
+// under MIT license.
+func TestSetGetFileEA(t *testing.T) {
+	testFilePath, testFile := setupTestFile(t)
+	testEAs := generateTestEAs(t, 3, testFilePath)
+	fileHandle := openFile(t, testFilePath, windows.FILE_ATTRIBUTE_NORMAL)
+	defer closeFileHandle(t, testFilePath, testFile, fileHandle)
+
+	testSetGetEA(t, testFilePath, fileHandle, testEAs)
+}
+
+// The code is new code and reuses code refactored from github.com/Microsoft/go-winio/blob/a7564fd482feb903f9562a135f1317fd3b480739/ea_test.go
+// under MIT license.
+func TestSetGetFolderEA(t *testing.T) {
+	testFolderPath := setupTestFolder(t)
+
+	testEAs := generateTestEAs(t, 3, testFolderPath)
+	fileHandle := openFile(t, testFolderPath, windows.FILE_ATTRIBUTE_NORMAL|windows.FILE_FLAG_BACKUP_SEMANTICS)
+	defer closeFileHandle(t, testFolderPath, nil, fileHandle)
+
+	testSetGetEA(t, testFolderPath, fileHandle, testEAs)
+}
+
+func setupTestFile(t *testing.T) (testFilePath string, testFile *os.File) {
+	tempDir := t.TempDir()
+	testFilePath = filepath.Join(tempDir, "testfile.txt")
+	var err error
+	if testFile, err = os.Create(testFilePath); err != nil {
+		t.Fatalf("failed to create temporary file: %s", err)
+	}
+	return testFilePath, testFile
+}
+
+func setupTestFolder(t *testing.T) string {
+	tempDir := t.TempDir()
+	testfolderPath := filepath.Join(tempDir, "testfolder")
+	if err := os.Mkdir(testfolderPath, os.ModeDir); err != nil {
+		t.Fatalf("failed to create temporary folder: %s", err)
+	}
+	return testfolderPath
+}
+
+func generateTestEAs(t *testing.T, nAttrs int, path string) []ExtendedAttribute {
+	testEAs := make([]ExtendedAttribute, nAttrs)
+	for i := 0; i < nAttrs; i++ {
+		testEAs[i].Name = fmt.Sprintf("TESTEA%d", i+1)
+		testEAs[i].Value = make([]byte, getRandomInt())
+		if _, err := rand.Read(testEAs[i].Value); err != nil {
+			t.Logf("Error reading rand for path %s: %v\n", path, err)
+		}
+	}
+	return testEAs
+}
+
+func getRandomInt() int64 {
+	nBig, err := rand.Int(rand.Reader, big.NewInt(27))
+	if err != nil {
+		panic(err)
+	}
+	n := nBig.Int64()
+	if n == 0 {
+		n = getRandomInt()
+	}
+	return n
+}
+
+func openFile(t *testing.T, path string, attributes uint32) windows.Handle {
+	utf16Path := windows.StringToUTF16Ptr(path)
+	fileAccessRightReadWriteEA := uint32(0x8 | 0x10)
+	fileHandle, err := windows.CreateFile(utf16Path, fileAccessRightReadWriteEA, 0, nil, windows.OPEN_EXISTING, attributes, 0)
+	if err != nil {
+		t.Fatalf("open file failed with: %s", err)
+	}
+	return fileHandle
+}
+
+func closeFileHandle(t *testing.T, testfilePath string, testFile *os.File, handle windows.Handle) {
+	if testFile != nil {
+		err := testFile.Close()
+		if err != nil {
+			t.Logf("Error closing file %s: %v\n", testFile.Name(), err)
+		}
+	}
+	if err := windows.Close(handle); err != nil {
+		t.Logf("Error closing file handle %s: %v\n", testfilePath, err)
+	}
+	cleanupTestFile(t, testfilePath)
+}
+
+func cleanupTestFile(t *testing.T, path string) {
+	if err := os.Remove(path); err != nil {
+		t.Logf("Error removing file/folder %s: %v\n", path, err)
+	}
+}
+
+func testSetGetEA(t *testing.T, path string, handle windows.Handle, testEAs []ExtendedAttribute) {
+	if err := SetFileEA(handle, testEAs); err != nil {
+		t.Fatalf("set EA for path %s failed: %s", path, err)
+	}
+
+	readEAs, err := GetFileEA(handle)
+	if err != nil {
+		t.Fatalf("get EA for path %s failed: %s", path, err)
+	}
+
+	if !reflect.DeepEqual(readEAs, testEAs) {
+		t.Logf("expected: %+v, found: %+v\n", testEAs, readEAs)
+		t.Fatalf("EAs read from path %s don't match", path)
+	}
+}

internal/fs/sd_windows.go

@@ -346,7 +346,7 @@ func getPrivilegeName(luid uint64) string {
 	return string(utf16.Decode(displayNameBuffer[:displayBufSize]))
 }
 
-// The functions below are copied over from https://github.com/microsoft/go-winio/blob/main/zsyscall_windows.go
+// The functions below are copied over from https://github.com/microsoft/go-winio/blob/main/zsyscall_windows.go under MIT license.
 
 // This windows api always returns an error even in case of success, warnings (partial success) and error cases.
 //
@@ -424,7 +424,7 @@ func _lookupPrivilegeValue(systemName *uint16, name *uint16, luid *uint64) (err
 	return
 }
 
-// The code below was copied from https://github.com/microsoft/go-winio/blob/main/tools/mkwinsyscall/mkwinsyscall.go
+// The code below was copied from https://github.com/microsoft/go-winio/blob/main/tools/mkwinsyscall/mkwinsyscall.go under MIT license.
 
 // errnoErr returns common boxed Errno values, to prevent
 // allocations at runtime.

internal/restic/node.go

@@ -284,16 +284,6 @@ func (node Node) restoreMetadata(path string, warn func(msg string)) error {
 	return firsterr
 }
 
-func (node Node) restoreExtendedAttributes(path string) error {
-	for _, attr := range node.ExtendedAttributes {
-		err := Setxattr(path, attr.Name, attr.Value)
-		if err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 func (node Node) RestoreTimestamps(path string) error {
 	var utimes = [...]syscall.Timespec{
 		syscall.NsecToTimespec(node.AccessTime.UnixNano()),
@@ -726,34 +716,6 @@ func (node *Node) fillExtra(path string, fi os.FileInfo, ignoreXattrListError bo
 	return err
 }
 
-func (node *Node) fillExtendedAttributes(path string, ignoreListError bool) error {
-	xattrs, err := Listxattr(path)
-	debug.Log("fillExtendedAttributes(%v) %v %v", path, xattrs, err)
-	if err != nil {
-		if ignoreListError && IsListxattrPermissionError(err) {
-			return nil
-		}
-		return err
-	}
-
-	node.ExtendedAttributes = make([]ExtendedAttribute, 0, len(xattrs))
-	for _, attr := range xattrs {
-		attrVal, err := Getxattr(path, attr)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "can not obtain extended attribute %v for %v:\n", attr, path)
-			continue
-		}
-		attr := ExtendedAttribute{
-			Name:  attr,
-			Value: attrVal,
-		}
-
-		node.ExtendedAttributes = append(node.ExtendedAttributes, attr)
-	}
-
-	return nil
-}
-
 func mkfifo(path string, mode uint32) (err error) {
 	return mknod(path, mode|syscall.S_IFIFO, 0)
 }

internal/restic/node_aix.go

@@ -23,25 +23,21 @@ func (s statT) atim() syscall.Timespec { return toTimespec(s.Atim) }
 func (s statT) mtim() syscall.Timespec { return toTimespec(s.Mtim) }
 func (s statT) ctim() syscall.Timespec { return toTimespec(s.Ctim) }
 
-// Getxattr is a no-op on AIX.
-func Getxattr(path, name string) ([]byte, error) {
-	return nil, nil
+// restoreExtendedAttributes is a no-op on AIX.
+func (node Node) restoreExtendedAttributes(_ string) error {
+	return nil
 }
 
-// Listxattr is a no-op on AIX.
-func Listxattr(path string) ([]string, error) {
-	return nil, nil
+// fillExtendedAttributes is a no-op on AIX.
+func (node *Node) fillExtendedAttributes(_ string, _ bool) error {
+	return nil
 }
 
+// IsListxattrPermissionError is a no-op on AIX.
 func IsListxattrPermissionError(_ error) bool {
 	return false
 }
 
-// Setxattr is a no-op on AIX.
-func Setxattr(path, name string, data []byte) error {
-	return nil
-}
-
 // restoreGenericAttributes is no-op on AIX.
 func (node *Node) restoreGenericAttributes(_ string, warn func(msg string)) error {
 	return node.handleAllUnknownGenericAttributesFound(warn)

internal/restic/node_netbsd.go

@@ -13,25 +13,21 @@ func (s statT) atim() syscall.Timespec { return s.Atimespec }
 func (s statT) mtim() syscall.Timespec { return s.Mtimespec }
 func (s statT) ctim() syscall.Timespec { return s.Ctimespec }
 
-// Getxattr is a no-op on netbsd.
-func Getxattr(path, name string) ([]byte, error) {
-	return nil, nil
+// restoreExtendedAttributes is a no-op on netbsd.
+func (node Node) restoreExtendedAttributes(_ string) error {
+	return nil
 }
 
-// Listxattr is a no-op on netbsd.
-func Listxattr(path string) ([]string, error) {
-	return nil, nil
+// fillExtendedAttributes is a no-op on netbsd.
+func (node *Node) fillExtendedAttributes(_ string, _ bool) error {
+	return nil
 }
 
+// IsListxattrPermissionError is a no-op on netbsd.
 func IsListxattrPermissionError(_ error) bool {
 	return false
 }
 
-// Setxattr is a no-op on netbsd.
-func Setxattr(path, name string, data []byte) error {
-	return nil
-}
-
 // restoreGenericAttributes is no-op on netbsd.
 func (node *Node) restoreGenericAttributes(_ string, warn func(msg string)) error {
 	return node.handleAllUnknownGenericAttributesFound(warn)

internal/restic/node_openbsd.go

@@ -13,25 +13,21 @@ func (s statT) atim() syscall.Timespec { return s.Atim }
 func (s statT) mtim() syscall.Timespec { return s.Mtim }
 func (s statT) ctim() syscall.Timespec { return s.Ctim }
 
-// Getxattr is a no-op on openbsd.
-func Getxattr(path, name string) ([]byte, error) {
-	return nil, nil
+// restoreExtendedAttributes is a no-op on openbsd.
+func (node Node) restoreExtendedAttributes(_ string) error {
+	return nil
 }
 
-// Listxattr is a no-op on openbsd.
-func Listxattr(path string) ([]string, error) {
-	return nil, nil
+// fillExtendedAttributes is a no-op on openbsd.
+func (node *Node) fillExtendedAttributes(_ string, _ bool) error {
+	return nil
 }
 
+// IsListxattrPermissionError is a no-op on openbsd.
 func IsListxattrPermissionError(_ error) bool {
 	return false
 }
 
-// Setxattr is a no-op on openbsd.
-func Setxattr(path, name string, data []byte) error {
-	return nil
-}
-
 // restoreGenericAttributes is no-op on openbsd.
 func (node *Node) restoreGenericAttributes(_ string, warn func(msg string)) error {
 	return node.handleAllUnknownGenericAttributesFound(warn)

internal/restic/node_test.go

@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"reflect"
 	"runtime"
+	"strings"
 	"testing"
 	"time"
 
@@ -205,8 +206,14 @@ func TestNodeRestoreAt(t *testing.T) {
 			var nodePath string
 			if test.ExtendedAttributes != nil {
 				if runtime.GOOS == "windows" {
-					// restic does not support xattrs on windows
-					return
+					// In windows extended attributes are case insensitive and windows returns
+					// the extended attributes in UPPER case.
+					// Update the tests to use UPPER case xattr names for windows.
+					extAttrArr := test.ExtendedAttributes
+					// Iterate through the array using pointers
+					for i := 0; i < len(extAttrArr); i++ {
+						extAttrArr[i].Name = strings.ToUpper(extAttrArr[i].Name)
+					}
 				}
 
 				// tempdir might be backed by a filesystem that does not support

internal/restic/node_windows.go

@@ -35,12 +35,12 @@ var (
 )
 
 // mknod is not supported on Windows.
-func mknod(_ string, mode uint32, dev uint64) (err error) {
+func mknod(_ string, _ uint32, _ uint64) (err error) {
 	return errors.New("device nodes cannot be created on windows")
 }
 
 // Windows doesn't need lchown
-func lchown(_ string, uid int, gid int) (err error) {
+func lchown(_ string, _ int, _ int) (err error) {
 	return nil
 }
 
@@ -70,23 +70,94 @@ func (node Node) restoreSymlinkTimestamps(path string, utimes [2]syscall.Timespe
 	return syscall.SetFileTime(h, nil, &a, &w)
 }
 
-// Getxattr retrieves extended attribute data associated with path.
-func Getxattr(path, name string) ([]byte, error) {
-	return nil, nil
+// restore extended attributes for windows
+func (node Node) restoreExtendedAttributes(path string) (err error) {
+	count := len(node.ExtendedAttributes)
+	if count > 0 {
+		eas := make([]fs.ExtendedAttribute, count)
+		for i, attr := range node.ExtendedAttributes {
+			eas[i] = fs.ExtendedAttribute{Name: attr.Name, Value: attr.Value}
+		}
+		if errExt := restoreExtendedAttributes(node.Type, path, eas); errExt != nil {
+			return errExt
+		}
+	}
+	return nil
 }
 
-// Listxattr retrieves a list of names of extended attributes associated with the
-// given path in the file system.
-func Listxattr(path string) ([]string, error) {
-	return nil, nil
+// fill extended attributes in the node. This also includes the Generic attributes for windows.
+func (node *Node) fillExtendedAttributes(path string, _ bool) (err error) {
+	var fileHandle windows.Handle
+	if fileHandle, err = getFileHandleForEA(node.Type, path); fileHandle == 0 {
+		return nil
+	}
+	if err != nil {
+		return errors.Errorf("get EA failed while opening file handle for path %v, with: %v", path, err)
+	}
+	defer closeFileHandle(fileHandle, path) // Replaced inline defer with named function call
+	//Get the windows Extended Attributes using the file handle
+	var extAtts []fs.ExtendedAttribute
+	extAtts, err = fs.GetFileEA(fileHandle)
+	debug.Log("fillExtendedAttributes(%v) %v", path, extAtts)
+	if err != nil {
+		return errors.Errorf("get EA failed for path %v, with: %v", path, err)
+	}
+	if len(extAtts) == 0 {
+		return nil
+	}
+
+	//Fill the ExtendedAttributes in the node using the name/value pairs in the windows EA
+	for _, attr := range extAtts {
+		extendedAttr := ExtendedAttribute{
+			Name:  attr.Name,
+			Value: attr.Value,
+		}
+
+		node.ExtendedAttributes = append(node.ExtendedAttributes, extendedAttr)
+	}
+	return nil
 }
 
-func IsListxattrPermissionError(_ error) bool {
-	return false
+// Get file handle for file or dir for setting/getting EAs
+func getFileHandleForEA(nodeType, path string) (handle windows.Handle, err error) {
+	switch nodeType {
+	case "file":
+		utf16Path := windows.StringToUTF16Ptr(path)
+		fileAccessRightReadWriteEA := (0x8 | 0x10)
+		handle, err = windows.CreateFile(utf16Path, uint32(fileAccessRightReadWriteEA), 0, nil, windows.OPEN_EXISTING, windows.FILE_ATTRIBUTE_NORMAL, 0)
+	case "dir":
+		utf16Path := windows.StringToUTF16Ptr(path)
+		fileAccessRightReadWriteEA := (0x8 | 0x10)
+		handle, err = windows.CreateFile(utf16Path, uint32(fileAccessRightReadWriteEA), 0, nil, windows.OPEN_EXISTING, windows.FILE_ATTRIBUTE_NORMAL|windows.FILE_FLAG_BACKUP_SEMANTICS, 0)
+	default:
+		return 0, nil
+	}
+	return handle, err
 }
 
-// Setxattr associates name and data together as an attribute of path.
-func Setxattr(path, name string, data []byte) error {
+// closeFileHandle safely closes a file handle and logs any errors.
+func closeFileHandle(fileHandle windows.Handle, path string) {
+	err := windows.CloseHandle(fileHandle)
+	if err != nil {
+		debug.Log("Error closing file handle for %s: %v\n", path, err)
+	}
+}
+
+// restoreExtendedAttributes handles restore of the Windows Extended Attributes to the specified path.
+// The Windows API requires setting of all the Extended Attributes in one call.
+func restoreExtendedAttributes(nodeType, path string, eas []fs.ExtendedAttribute) (err error) {
+	var fileHandle windows.Handle
+	if fileHandle, err = getFileHandleForEA(nodeType, path); fileHandle == 0 {
+		return nil
+	}
+	if err != nil {
+		return errors.Errorf("set EA failed while opening file handle for path %v, with: %v", path, err)
+	}
+	defer closeFileHandle(fileHandle, path) // Replaced inline defer with named function call
+
+	if err = fs.SetFileEA(fileHandle, eas); err != nil {
+		return errors.Errorf("set EA failed for path %v, with: %v", path, err)
+	}
 	return nil
 }
 

internal/restic/node_windows_test.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"strings"
 	"syscall"
 	"testing"
 
@@ -265,3 +266,66 @@ func TestNewGenericAttributeType(t *testing.T) {
 		test.Assert(t, len(ua) == 0, "Unkown attributes: %s found for path: %s", ua, testPath)
 	}
 }
+
+func TestRestoreExtendedAttributes(t *testing.T) {
+	t.Parallel()
+	tempDir := t.TempDir()
+	expectedNodes := []Node{
+		{
+			Name:       "testfile",
+			Type:       "file",
+			Mode:       0644,
+			ModTime:    parseTime("2005-05-14 21:07:03.111"),
+			AccessTime: parseTime("2005-05-14 21:07:04.222"),
+			ChangeTime: parseTime("2005-05-14 21:07:05.333"),
+			ExtendedAttributes: []ExtendedAttribute{
+				{"user.foo", []byte("bar")},
+			},
+		},
+		{
+			Name:       "testdirectory",
+			Type:       "dir",
+			Mode:       0755,
+			ModTime:    parseTime("2005-05-14 21:07:03.111"),
+			AccessTime: parseTime("2005-05-14 21:07:04.222"),
+			ChangeTime: parseTime("2005-05-14 21:07:05.333"),
+			ExtendedAttributes: []ExtendedAttribute{
+				{"user.foo", []byte("bar")},
+			},
+		},
+	}
+	for _, testNode := range expectedNodes {
+		testPath, node := restoreAndGetNode(t, tempDir, testNode, false)
+
+		var handle windows.Handle
+		var err error
+		utf16Path := windows.StringToUTF16Ptr(testPath)
+		if node.Type == "file" {
+			handle, err = windows.CreateFile(utf16Path, windows.FILE_READ_EA, 0, nil, windows.OPEN_EXISTING, windows.FILE_ATTRIBUTE_NORMAL, 0)
+		} else if node.Type == "dir" {
+			handle, err = windows.CreateFile(utf16Path, windows.FILE_READ_EA, 0, nil, windows.OPEN_EXISTING, windows.FILE_ATTRIBUTE_NORMAL|windows.FILE_FLAG_BACKUP_SEMANTICS, 0)
+		}
+		test.OK(t, errors.Wrapf(err, "Error opening file/directory for: %s", testPath))
+		defer func() {
+			err := windows.Close(handle)
+			test.OK(t, errors.Wrapf(err, "Error closing file for: %s", testPath))
+		}()
+
+		extAttr, err := fs.GetFileEA(handle)
+		test.OK(t, errors.Wrapf(err, "Error getting extended attributes for: %s", testPath))
+		test.Equals(t, len(node.ExtendedAttributes), len(extAttr))
+
+		for _, expectedExtAttr := range node.ExtendedAttributes {
+			var foundExtAttr *fs.ExtendedAttribute
+			for _, ea := range extAttr {
+				if strings.EqualFold(ea.Name, expectedExtAttr.Name) {
+					foundExtAttr = &ea
+					break
+
+				}
+			}
+			test.Assert(t, foundExtAttr != nil, "Expected extended attribute not found")
+			test.Equals(t, expectedExtAttr.Value, foundExtAttr.Value)
+		}
+	}
+}

internal/restic/node_xattr.go

@@ -4,23 +4,25 @@
 package restic
 
 import (
+	"fmt"
 	"os"
 	"syscall"
 
+	"github.com/restic/restic/internal/debug"
 	"github.com/restic/restic/internal/errors"
 
 	"github.com/pkg/xattr"
 )
 
-// Getxattr retrieves extended attribute data associated with path.
-func Getxattr(path, name string) ([]byte, error) {
+// getxattr retrieves extended attribute data associated with path.
+func getxattr(path, name string) ([]byte, error) {
 	b, err := xattr.LGet(path, name)
 	return b, handleXattrErr(err)
 }
 
-// Listxattr retrieves a list of names of extended attributes associated with the
+// listxattr retrieves a list of names of extended attributes associated with the
 // given path in the file system.
-func Listxattr(path string) ([]string, error) {
+func listxattr(path string) ([]string, error) {
 	l, err := xattr.LList(path)
 	return l, handleXattrErr(err)
 }
@@ -33,8 +35,8 @@ func IsListxattrPermissionError(err error) bool {
 	return false
 }
 
-// Setxattr associates name and data together as an attribute of path.
-func Setxattr(path, name string, data []byte) error {
+// setxattr associates name and data together as an attribute of path.
+func setxattr(path, name string, data []byte) error {
 	return handleXattrErr(xattr.LSet(path, name, data))
 }
 
@@ -66,3 +68,41 @@ func (node *Node) restoreGenericAttributes(_ string, warn func(msg string)) erro
 func (node *Node) fillGenericAttributes(_ string, _ os.FileInfo, _ *statT) (allowExtended bool, err error) {
 	return true, nil
 }
+
+func (node Node) restoreExtendedAttributes(path string) error {
+	for _, attr := range node.ExtendedAttributes {
+		err := setxattr(path, attr.Name, attr.Value)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (node *Node) fillExtendedAttributes(path string, ignoreListError bool) error {
+	xattrs, err := listxattr(path)
+	debug.Log("fillExtendedAttributes(%v) %v %v", path, xattrs, err)
+	if err != nil {
+		if ignoreListError && IsListxattrPermissionError(err) {
+			return nil
+		}
+		return err
+	}
+
+	node.ExtendedAttributes = make([]ExtendedAttribute, 0, len(xattrs))
+	for _, attr := range xattrs {
+		attrVal, err := getxattr(path, attr)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "can not obtain extended attribute %v for %v:\n", attr, path)
+			continue
+		}
+		attr := ExtendedAttribute{
+			Name:  attr,
+			Value: attrVal,
+		}
+
+		node.ExtendedAttributes = append(node.ExtendedAttributes, attr)
+	}
+
+	return nil
+}