hatter/go-afero-encfs
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feat: working in process

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This commit is contained in:
Hatter Jiang
2024-09-01 17:44:33 +08:00
parent 84c0e2e872
commit df2a6d45b7
4 changed files with 185 additions and 159 deletions
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139
encfs/file.go
View File

@@ -1,11 +1,18 @@
package encfs
import (
"crypto/aes"
"crypto/rand"
"encoding/binary"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
"io"
"io/fs"
"math"
"os"
"strings"
"syscall"
"github.com/spf13/afero"
@@ -52,7 +59,7 @@ func newEncFileMeta(name string) (*EncFileMeta, error) {
}
func openEncFileMeta(name string) (*EncFileMeta, error) {
encFileMetaName := name + "." + EncFileExt
encFileMetaName := name + EncFileExt
encFileMetaFile, err := os.Open(encFileMetaName)
if err != nil {
if os.IsNotExist(err) {
@@ -91,10 +98,12 @@ type EncFile struct {
isDir bool
closed bool
encFileMeta *EncFileMeta
encFs *EncFs
filePos int64
file *os.File
}
func NewEncFile(name string, file *os.File, isCreate bool) (*EncFile, error) {
func NewEncFile(name string, file *os.File, encFs *EncFs, isCreate bool) (*EncFile, error) {
fileInfo, err := file.Stat()
if err != nil {
return nil, err
@@ -115,6 +124,8 @@ func NewEncFile(name string, file *os.File, isCreate bool) (*EncFile, error) {
isDir: isDir,
closed: false,
encFileMeta: encFileMeta,
encFs: encFs,
filePos: 0,
file: file,
}, nil
}
@@ -134,8 +145,21 @@ func (f *EncFile) Read(p []byte) (n int, err error) {
return 0, checkIsFileErr
}
// TODO decrypt
return f.file.Read(p)
beforeReadFilePos := f.filePos
readLen, err := f.file.Read(p)
if err == nil {
f.filePos += int64(readLen)
if f.encFs != nil && f.encFs.key != nil && f.encFileMeta != nil {
encryptedBytes, err := generateCtrEncryptBytes(f.encFs.key, f.encFileMeta.Iv, beforeReadFilePos, int64(readLen))
if err != nil {
return 0, err
}
for i := 0; i < readLen; i++ {
p[i] = p[i] ^ encryptedBytes[i]
}
}
}
return readLen, err
}
func (f *EncFile) ReadAt(p []byte, off int64) (n int, err error) {
@@ -153,8 +177,6 @@ func (f *EncFile) Seek(offset int64, whence int) (int64, error) {
if checkIsFileErr != nil {
return 0, checkIsFileErr
}
// TODO decrypt
return f.file.Seek(offset, whence)
}
@@ -164,8 +186,24 @@ func (f *EncFile) Write(p []byte) (n int, err error) {
return 0, checkIsFileErr
}
// TODO encrypt
return f.file.Write(p)
writeBuff := p
if f.encFs != nil && f.encFs.key != nil && f.encFileMeta != nil {
buff := make([]byte, len(p))
encryptedBytes, err := generateCtrEncryptBytes(f.encFs.key, f.encFileMeta.Iv, f.filePos, int64(len(p)))
if err != nil {
return 0, err
}
for i := 0; i < len(p); i++ {
buff[i] = p[i] ^ encryptedBytes[i]
}
writeBuff = buff
}
writeLen, err := f.file.Write(writeBuff)
if err == nil {
f.filePos += int64(writeLen)
}
return writeLen, err
}
func (f *EncFile) WriteAt(p []byte, off int64) (n int, err error) {
@@ -174,8 +212,24 @@ func (f *EncFile) WriteAt(p []byte, off int64) (n int, err error) {
return 0, checkIsFileErr
}
// TODO encrypt
return f.file.WriteAt(p, off)
writeBuff := p
if f.encFs != nil && f.encFs.key != nil && f.encFileMeta != nil {
buff := make([]byte, len(p))
encryptedBytes, err := generateCtrEncryptBytes(f.encFs.key, f.encFileMeta.Iv, off, int64(len(p)))
if err != nil {
return 0, err
}
for i := 0; i < len(p); i++ {
buff[i] = p[i] ^ encryptedBytes[i]
}
writeBuff = buff
}
writeLen, err := f.file.WriteAt(writeBuff, off)
// if err == nil {
// f.filePos += int64(writeLen)
// }
return writeLen, err
}
func (f *EncFile) Name() string {
@@ -187,7 +241,27 @@ func (f *EncFile) Readdir(count int) ([]os.FileInfo, error) {
return nil, afero.ErrFileClosed
}
return f.file.Readdir(count)
// FIXME is count * 2 just ok?
fileInfos, err := f.file.Readdir(count * 2)
if err != nil {
return nil, err
}
if count == 0 {
return make([]fs.FileInfo, 0), nil
}
filterFileInfos := make([]os.FileInfo, 0)
for _, fileInfo := range fileInfos {
isEncFileMetaFile := strings.HasSuffix(fileInfo.Name(), EncFileExt)
if !isEncFileMetaFile {
filterFileInfos = append(filterFileInfos, fileInfo)
}
if count >= 0 && len(filterFileInfos) >= count {
break
}
}
return filterFileInfos, nil
}
func (f *EncFile) Readdirnames(n int) ([]string, error) {
@@ -230,3 +304,46 @@ func (f *EncFile) checkIsFile() error {
}
return nil
}
func generateCtrEncryptBytes(key, iv []byte, offset, len int64) ([]byte, error) {
endOffset := offset + len
encryptStartOffset := (offset / 16) * 16
encryptEndOffset := (endOffset / 16) * 16
if endOffset%16 > 0 {
encryptEndOffset += 16
}
blocksCount := int((encryptEndOffset - encryptStartOffset) / 16)
cipher, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
encryptBytes := make([]byte, blocksCount*16)
for i := 0; i < blocksCount; i++ {
encNonce := nonceAdd(iv, uint64(i))
cipher.Encrypt(encryptBytes[i*16:(i+1)*16], encNonce)
}
// fmt.Println("XX ", hex.EncodeToString(encryptBytes))
encryptedBytes := encryptBytes[offset-encryptStartOffset : offset-encryptStartOffset+len]
fmt.Println("XX", hex.EncodeToString(key), hex.EncodeToString(iv), offset, len, hex.EncodeToString(encryptedBytes))
return encryptedBytes, nil
}
func nonceAdd(nonce []byte, incrementValue uint64) []byte {
n1 := binary.BigEndian.Uint64(nonce[:8])
n2 := binary.BigEndian.Uint64(nonce[8:])
leftToMax := math.MaxUint64 - n2
if leftToMax <= incrementValue {
incrementValue -= leftToMax + 1
n2 = incrementValue
n1 += 1
} else {
n2 += incrementValue
}
newNonce := make([]byte, 16)
binary.BigEndian.PutUint64(newNonce, n1)
binary.BigEndian.PutUint64(newNonce[8:], n2)
return newNonce
}

53
encfs/fs.go
View File

@@ -10,15 +10,19 @@ import (
// copied from afero/os.go
type EncFs struct{}
func NewEncFs() afero.Fs {
return &EncFs{}
type EncFs struct {
key []byte
}
func (EncFs) Name() string { return "EncFs" }
func NewEncFs(key []byte) afero.Fs {
return &EncFs{
key: key,
}
}
func (EncFs) Create(name string) (afero.File, error) {
func (*EncFs) Name() string { return "EncFs" }
func (encFs *EncFs) Create(name string) (afero.File, error) {
if err := checkFileExt(name); err != nil {
return nil, err
}
@@ -28,18 +32,18 @@ func (EncFs) Create(name string) (afero.File, error) {
// a nil value of type *os.File or nil won't be nil
return nil, e
}
return convertOsFileToEncFile(name, f, e, true)
return convertOsFileToEncFile(name, f, e, encFs, true)
}
func (EncFs) Mkdir(name string, perm os.FileMode) error {
func (*EncFs) Mkdir(name string, perm os.FileMode) error {
return os.Mkdir(name, perm)
}
func (EncFs) MkdirAll(path string, perm os.FileMode) error {
func (*EncFs) MkdirAll(path string, perm os.FileMode) error {
return os.MkdirAll(path, perm)
}
func (EncFs) Open(name string) (afero.File, error) {
func (encFs *EncFs) Open(name string) (afero.File, error) {
if err := checkFileExt(name); err != nil {
return nil, err
}
@@ -49,10 +53,10 @@ func (EncFs) Open(name string) (afero.File, error) {
// a nil value of type *os.File or nil won't be nil
return nil, e
}
return convertOsFileToEncFile(name, f, e, false)
return convertOsFileToEncFile(name, f, e, encFs, false)
}
func (EncFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
func (*EncFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
f, e := os.OpenFile(name, flag, perm)
if f == nil {
// while this looks strange, we need to return a bare nil (of type nil) not
@@ -62,47 +66,47 @@ func (EncFs) OpenFile(name string, flag int, perm os.FileMode) (afero.File, erro
return f, e
}
func (EncFs) Remove(name string) error {
func (*EncFs) Remove(name string) error {
// TODO remove enc file meta
return os.Remove(name)
}
func (EncFs) RemoveAll(path string) error {
func (*EncFs) RemoveAll(path string) error {
// TODO remove enc file meta
return os.RemoveAll(path)
}
func (EncFs) Rename(oldname, newname string) error {
func (*EncFs) Rename(oldname, newname string) error {
// TODO rename enc file meta
return os.Rename(oldname, newname)
}
func (EncFs) Stat(name string) (os.FileInfo, error) {
func (*EncFs) Stat(name string) (os.FileInfo, error) {
return os.Stat(name)
}
func (EncFs) Chmod(name string, mode os.FileMode) error {
func (*EncFs) Chmod(name string, mode os.FileMode) error {
return os.Chmod(name, mode)
}
func (EncFs) Chown(name string, uid, gid int) error {
func (*EncFs) Chown(name string, uid, gid int) error {
return os.Chown(name, uid, gid)
}
func (EncFs) Chtimes(name string, atime time.Time, mtime time.Time) error {
func (*EncFs) Chtimes(name string, atime time.Time, mtime time.Time) error {
return os.Chtimes(name, atime, mtime)
}
func (EncFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
func (*EncFs) LstatIfPossible(name string) (os.FileInfo, bool, error) {
fi, err := os.Lstat(name)
return fi, true, err
}
func (EncFs) SymlinkIfPossible(oldname, newname string) error {
func (*EncFs) SymlinkIfPossible(oldname, newname string) error {
return os.Symlink(oldname, newname)
}
func (EncFs) ReadlinkIfPossible(name string) (string, error) {
func (*EncFs) ReadlinkIfPossible(name string) (string, error) {
return os.Readlink(name)
}
@@ -113,12 +117,11 @@ func checkFileExt(name string) error {
return nil
}
func convertOsFileToEncFile(name string, file *os.File, e error, isCreate bool) (afero.File, error) {
func convertOsFileToEncFile(name string, file *os.File, e error, encFs *EncFs, isCreate bool) (afero.File, error) {
if e != nil {
return nil, e
}
// TODO add password, and IV etc ...
encFile, err := NewEncFile(name, file, isCreate)
encFile, err := NewEncFile(name, file, encFs, isCreate)
if err != nil {
return nil, err
}