Cleanup and rename files
This commit is contained in:
Jakob Unterwurzacher
parent
7e564f928f
commit
11fb037e7e
@ -1,226 +0,0 @@
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package cryptfs
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import (
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//"fmt"
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"os"
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//"io"
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"errors"
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"crypto/cipher"
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)
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type CryptFile struct {
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file *os.File
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gcm cipher.AEAD
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}
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// decryptBlock - Verify and decrypt GCM block
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func (be *CryptFS) DecryptBlock(ciphertext []byte) ([]byte, error) {
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// Empty block?
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if len(ciphertext) == 0 {
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return ciphertext, nil
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}
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if len(ciphertext) < NONCE_LEN {
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warn.Printf("decryptBlock: Block is too short: %d bytes\n", len(ciphertext))
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return nil, errors.New("Block is too short")
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}
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// Extract nonce
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nonce := ciphertext[:NONCE_LEN]
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ciphertext = ciphertext[NONCE_LEN:]
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// Decrypt
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var plaintext []byte
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plaintext, err := be.gcm.Open(plaintext, nonce, ciphertext, nil)
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if err != nil {
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return nil, err
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}
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return plaintext, nil
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}
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// encryptBlock - Encrypt and add MAC using GCM
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func (be *CryptFS) EncryptBlock(plaintext []byte) []byte {
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// Empty block?
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if len(plaintext) == 0 {
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return plaintext
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}
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// Get fresh nonce
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nonce := gcmNonce.Get()
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// Encrypt plaintext and append to nonce
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ciphertext := be.gcm.Seal(nonce, nonce, plaintext, nil)
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return ciphertext
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}
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/*
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// readCipherBlock - Read ciphertext block number "blockNo", decrypt,
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// return plaintext
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func (be *CryptFile) readCipherBlock(blockNo int64) ([]byte, error) {
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off := blockNo * int64(be.cipherBS)
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buf := make([]byte, be.cipherBS)
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readN, err := be.file.ReadAt(buf, off)
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if err != nil && err != io.EOF {
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return nil, err
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}
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// Truncate buffer to actually read bytes
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buf = buf[:readN]
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// Empty block?
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if len(buf) == 0 {
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return buf, nil
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}
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if len(buf) < NONCE_LEN {
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warn.Printf("readCipherBlock: Block is too short: %d bytes\n", len(buf))
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return nil, errors.New("Block is too short")
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}
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// Extract nonce
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nonce := buf[:NONCE_LEN]
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buf = buf[NONCE_LEN:]
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// Decrypt
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var plainBuf []byte
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plainBuf, err = be.gcm.Open(plainBuf, nonce, buf, nil)
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if err != nil {
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fmt.Printf("gcm.Open() failed: %d\n", err)
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return nil, err
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}
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return plainBuf, nil
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}
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*/
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// intraBlock identifies a part of a file block
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type intraBlock struct {
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BlockNo uint64 // Block number in file
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Offset uint64 // Offset into block plaintext
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Length uint64 // Length of data from this block
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fs *CryptFS
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}
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// isPartial - is the block partial? This means we have to do read-modify-write.
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func (ib *intraBlock) IsPartial() bool {
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if ib.Offset > 0 || ib.Length < ib.fs.plainBS {
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return true
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}
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return false
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}
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// CiphertextRange - get byte range in ciphertext file corresponding to BlockNo
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// (complete block)
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func (ib *intraBlock) CiphertextRange() (offset uint64, length uint64) {
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return ib.BlockNo * ib.fs.cipherBS, ib.fs.cipherBS
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}
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// PlaintextRange - get byte range in plaintext corresponding to BlockNo
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// (complete block)
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func (ib *intraBlock) PlaintextRange() (offset uint64, length uint64) {
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return ib.BlockNo * ib.fs.plainBS, ib.fs.plainBS
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}
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// CropBlock - crop a potentially larger plaintext block down to the relevant part
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func (ib *intraBlock) CropBlock(d []byte) []byte{
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lenHave := len(d)
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lenWant := int(ib.Offset+ib.Length)
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if lenHave < lenWant {
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return d[ib.Offset:lenHave]
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}
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return d[ib.Offset:lenWant]
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}
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// Split a plaintext byte range into (possible partial) blocks
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func (be *CryptFS) SplitRange(offset uint64, length uint64) []intraBlock {
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var b intraBlock
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var parts []intraBlock
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b.fs = be
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for length > 0 {
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b.BlockNo = offset / be.plainBS
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b.Offset = offset % be.plainBS
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b.Length = be.minu64(length, be.plainBS - b.Offset)
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parts = append(parts, b)
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offset += b.Length
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length -= b.Length
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}
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return parts
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}
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func (be *CryptFS) minu64(x uint64, y uint64) uint64 {
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if x < y {
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return x
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}
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return y
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}
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/*
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// writeCipherBlock - Encrypt plaintext and write it to file block "blockNo"
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func (be *CryptFile) writeCipherBlock(blockNo int64, plain []byte) error {
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if int64(len(plain)) > be.plainBS {
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panic("writeCipherBlock: Cannot write block that is larger than plainBS")
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}
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// Get fresh nonce
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nonce := gcmNonce.Get()
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// Encrypt data and append to nonce
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cipherBuf := be.gcm.Seal(nonce, nonce, plain, nil)
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// WriteAt retries short writes autmatically
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written, err := be.file.WriteAt(cipherBuf, blockNo * be.cipherBS)
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debug.Printf("writeCipherBlock: wrote %d ciphertext bytes to block %d\n",
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written, blockNo)
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return err
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}
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// Perform RMW cycle on block
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// Write "data" into file location specified in "b"
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func (be *CryptFile) rmwWrite(b intraBlock, data []byte, f *os.File) error {
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if b.Length != uint64(len(data)) {
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panic("Length mismatch")
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}
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oldBlock, err := be.readCipherBlock(b.BlockNo)
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if err != nil {
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return err
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}
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newBlockLen := b.Offset + b.Length
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debug.Printf("newBlockLen := %d + %d\n", b.Offset, b.Length)
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var newBlock []byte
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// Write goes beyond the old block and grows the file?
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// Must create a bigger newBlock
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if newBlockLen > uint64(len(oldBlock)) {
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newBlock = make([]byte, newBlockLen)
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} else {
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newBlock = make([]byte, len(oldBlock))
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}
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// Fill with old data
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copy(newBlock, oldBlock)
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// Then overwrite the relevant parts with new data
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copy(newBlock[b.Offset:b.Offset + b.Length], data)
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// Actual write
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err = be.writeCipherBlock(b.BlockNo, newBlock)
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if err != nil {
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// An incomplete write to a ciphertext block means that the whole block
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// is destroyed.
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fmt.Printf("rmwWrite: Write error: %s\n", err)
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}
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return err
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}
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*/
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@ -1,21 +1,16 @@
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package cryptfs
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// CryptFS is the crypto backend of GoCryptFS
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import (
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"crypto/cipher"
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"crypto/aes"
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"fmt"
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"strings"
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"encoding/base64"
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"errors"
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)
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const (
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NONCE_LEN = 12
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AUTH_TAG_LEN = 16
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DEFAULT_PLAINBS = 4096
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ENCRYPT = true
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DECRYPT = false
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)
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type CryptFS struct {
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@ -45,169 +40,6 @@ func NewCryptFS(key [16]byte) *CryptFS {
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}
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}
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/*
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func (fs *CryptFS) NewFile(f *os.File) *CryptFile {
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return &CryptFile {
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file: f,
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gcm: fs.gcm,
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plainBS: fs.plainBS,
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cipherBS: fs.cipherBS,
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}
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}
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*/
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func (be *CryptFS) PlainBS() uint64 {
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return be.plainBS
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}
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// DecryptName - decrypt filename
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func (be *CryptFS) decryptName(cipherName string) (string, error) {
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bin, err := base64.URLEncoding.DecodeString(cipherName)
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if err != nil {
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return "", err
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}
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if len(bin) % aes.BlockSize != 0 {
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return "", errors.New(fmt.Sprintf("Name len=%d is not a multiple of 16", len(bin)))
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}
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iv := make([]byte, aes.BlockSize) // TODO ?
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cbc := cipher.NewCBCDecrypter(be.blockCipher, iv)
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cbc.CryptBlocks(bin, bin)
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bin, err = be.unPad16(bin)
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if err != nil {
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return "", err
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}
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plain := string(bin)
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return plain, err
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}
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// EncryptName - encrypt filename
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func (be *CryptFS) encryptName(plainName string) string {
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bin := []byte(plainName)
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bin = be.pad16(bin)
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iv := make([]byte, 16) // TODO ?
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cbc := cipher.NewCBCEncrypter(be.blockCipher, iv)
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cbc.CryptBlocks(bin, bin)
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cipherName64 := base64.URLEncoding.EncodeToString(bin)
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return cipherName64
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}
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// TranslatePath - encrypt or decrypt path. Just splits the string on "/"
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// and hands the parts to EncryptName() / DecryptName()
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func (be *CryptFS) translatePath(path string, op bool) (string, error) {
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var err error
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// Empty string means root directory
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if path == "" {
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return path, err
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}
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// Run operation on each path component
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var translatedParts []string
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parts := strings.Split(path, "/")
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for _, part := range parts {
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var newPart string
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if op == ENCRYPT {
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newPart = be.encryptName(part)
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} else {
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newPart, err = be.decryptName(part)
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if err != nil {
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return "", err
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}
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}
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translatedParts = append(translatedParts, newPart)
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}
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return strings.Join(translatedParts, "/"), err
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}
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// EncryptPath - encrypt filename or path. Just hands it to TranslatePath().
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func (be *CryptFS) EncryptPath(path string) string {
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newPath, _ := be.translatePath(path, ENCRYPT)
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return newPath
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}
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// DecryptPath - decrypt filename or path. Just hands it to TranslatePath().
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func (be *CryptFS) DecryptPath(path string) (string, error) {
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return be.translatePath(path, DECRYPT)
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}
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// PlainSize - calculate plaintext size from ciphertext size
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func (be *CryptFS) PlainSize(size uint64) uint64 {
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// Zero sized files stay zero-sized
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if size > 0 {
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overhead := be.cipherBS - be.plainBS
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nBlocks := (size + be.cipherBS - 1) / be.cipherBS
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size -= nBlocks * overhead
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}
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return size
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}
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// plainSizeFromCipherSize - calculate plaintext size from ciphertext size
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func (be *CryptFS) plainSizeFromCipherSize(size int64) int64 {
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if size > 0 {
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}
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return size
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}
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// pad16 - pad filename to 16 byte blocks using standard PKCS#7 padding
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// https://tools.ietf.org/html/rfc5652#section-6.3
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func (be *CryptFS) pad16(orig []byte) (padded []byte) {
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oldLen := len(orig)
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if oldLen == 0 {
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panic("Padding zero-length string makes no sense")
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}
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padLen := aes.BlockSize - oldLen % aes.BlockSize
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if padLen == 0 {
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padLen = aes.BlockSize
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}
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newLen := oldLen + padLen
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padded = make([]byte, newLen)
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copy(padded, orig)
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padByte := byte(padLen)
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for i := oldLen; i < newLen; i++ {
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padded[i] = padByte
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}
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return padded
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}
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// unPad16 - remove padding
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func (be *CryptFS) unPad16(orig []byte) ([]byte, error) {
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oldLen := len(orig)
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if oldLen % aes.BlockSize != 0 {
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return nil, errors.New("Unaligned size")
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}
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// The last byte is always a padding byte
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padByte := orig[oldLen -1]
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// The padding byte's value is the padding length
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padLen := int(padByte)
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// Padding must be at least 1 byte
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if padLen <= 0 {
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return nil, errors.New("Padding cannot be zero-length")
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}
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// Larger paddings make no sense
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if padLen > aes.BlockSize {
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return nil, errors.New("Padding cannot be larger than 16")
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}
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// All padding bytes must be identical
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for i := oldLen - padLen; i < oldLen; i++ {
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if orig[i] != padByte {
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return nil, errors.New(fmt.Sprintf("Padding byte at i=%d is invalid", i))
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}
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}
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newLen := oldLen - padLen
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// Padding an empty string makes no sense
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if newLen == 0 {
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return nil, errors.New("Unpadded length is zero")
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}
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return orig[0:newLen], nil
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}
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94
cryptfs/cryptfs_content.go
Normal file
94
cryptfs/cryptfs_content.go
Normal file
@ -0,0 +1,94 @@
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package cryptfs
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// File content encryption / decryption
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import (
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"os"
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"errors"
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"crypto/cipher"
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)
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type CryptFile struct {
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file *os.File
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gcm cipher.AEAD
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}
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// decryptBlock - Verify and decrypt GCM block
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func (be *CryptFS) DecryptBlock(ciphertext []byte) ([]byte, error) {
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// Empty block?
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if len(ciphertext) == 0 {
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return ciphertext, nil
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}
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if len(ciphertext) < NONCE_LEN {
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warn.Printf("decryptBlock: Block is too short: %d bytes\n", len(ciphertext))
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return nil, errors.New("Block is too short")
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}
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// Extract nonce
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nonce := ciphertext[:NONCE_LEN]
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ciphertext = ciphertext[NONCE_LEN:]
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// Decrypt
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var plaintext []byte
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plaintext, err := be.gcm.Open(plaintext, nonce, ciphertext, nil)
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if err != nil {
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return nil, err
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}
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return plaintext, nil
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}
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// encryptBlock - Encrypt and add MAC using GCM
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func (be *CryptFS) EncryptBlock(plaintext []byte) []byte {
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// Empty block?
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if len(plaintext) == 0 {
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return plaintext
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}
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// Get fresh nonce
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nonce := gcmNonce.Get()
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// Encrypt plaintext and append to nonce
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ciphertext := be.gcm.Seal(nonce, nonce, plaintext, nil)
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return ciphertext
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}
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// Split a plaintext byte range into (possible partial) blocks
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func (be *CryptFS) SplitRange(offset uint64, length uint64) []intraBlock {
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var b intraBlock
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var parts []intraBlock
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b.fs = be
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for length > 0 {
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b.BlockNo = offset / be.plainBS
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b.Offset = offset % be.plainBS
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b.Length = be.minu64(length, be.plainBS - b.Offset)
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parts = append(parts, b)
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offset += b.Length
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length -= b.Length
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}
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return parts
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}
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// PlainSize - calculate plaintext size from ciphertext size
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func (be *CryptFS) PlainSize(size uint64) uint64 {
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// Zero sized files stay zero-sized
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if size > 0 {
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overhead := be.cipherBS - be.plainBS
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nBlocks := (size + be.cipherBS - 1) / be.cipherBS
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size -= nBlocks * overhead
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}
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return size
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}
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func (be *CryptFS) minu64(x uint64, y uint64) uint64 {
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if x < y {
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return x
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}
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return y
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}
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150
cryptfs/cryptfs_names.go
Normal file
150
cryptfs/cryptfs_names.go
Normal file
@ -0,0 +1,150 @@
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package cryptfs
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// Filename encryption / decryption function
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import (
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"crypto/cipher"
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"crypto/aes"
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"fmt"
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"strings"
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"encoding/base64"
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"errors"
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)
|
||||
|
||||
const (
|
||||
ENCRYPT = true
|
||||
DECRYPT = false
|
||||
)
|
||||
|
||||
// DecryptName - decrypt filename
|
||||
func (be *CryptFS) decryptName(cipherName string) (string, error) {
|
||||
|
||||
bin, err := base64.URLEncoding.DecodeString(cipherName)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
if len(bin) % aes.BlockSize != 0 {
|
||||
return "", errors.New(fmt.Sprintf("Name len=%d is not a multiple of 16", len(bin)))
|
||||
}
|
||||
|
||||
iv := make([]byte, aes.BlockSize) // TODO ?
|
||||
cbc := cipher.NewCBCDecrypter(be.blockCipher, iv)
|
||||
cbc.CryptBlocks(bin, bin)
|
||||
|
||||
bin, err = be.unPad16(bin)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
|
||||
plain := string(bin)
|
||||
return plain, err
|
||||
}
|
||||
|
||||
// EncryptName - encrypt filename
|
||||
func (be *CryptFS) encryptName(plainName string) string {
|
||||
|
||||
bin := []byte(plainName)
|
||||
bin = be.pad16(bin)
|
||||
|
||||
iv := make([]byte, 16) // TODO ?
|
||||
cbc := cipher.NewCBCEncrypter(be.blockCipher, iv)
|
||||
cbc.CryptBlocks(bin, bin)
|
||||
|
||||
cipherName64 := base64.URLEncoding.EncodeToString(bin)
|
||||
|
||||
return cipherName64
|
||||
}
|
||||
|
||||
// TranslatePath - encrypt or decrypt path. Just splits the string on "/"
|
||||
// and hands the parts to EncryptName() / DecryptName()
|
||||
func (be *CryptFS) translatePath(path string, op bool) (string, error) {
|
||||
var err error
|
||||
|
||||
// Empty string means root directory
|
||||
if path == "" {
|
||||
return path, err
|
||||
}
|
||||
|
||||
// Run operation on each path component
|
||||
var translatedParts []string
|
||||
parts := strings.Split(path, "/")
|
||||
for _, part := range parts {
|
||||
var newPart string
|
||||
if op == ENCRYPT {
|
||||
newPart = be.encryptName(part)
|
||||
} else {
|
||||
newPart, err = be.decryptName(part)
|
||||
if err != nil {
|
||||
return "", err
|
||||
}
|
||||
}
|
||||
translatedParts = append(translatedParts, newPart)
|
||||
}
|
||||
|
||||
return strings.Join(translatedParts, "/"), err
|
||||
}
|
||||
|
||||
// EncryptPath - encrypt filename or path. Just hands it to TranslatePath().
|
||||
func (be *CryptFS) EncryptPath(path string) string {
|
||||
newPath, _ := be.translatePath(path, ENCRYPT)
|
||||
return newPath
|
||||
}
|
||||
|
||||
// DecryptPath - decrypt filename or path. Just hands it to TranslatePath().
|
||||
func (be *CryptFS) DecryptPath(path string) (string, error) {
|
||||
return be.translatePath(path, DECRYPT)
|
||||
}
|
||||
|
||||
// pad16 - pad filename to 16 byte blocks using standard PKCS#7 padding
|
||||
// https://tools.ietf.org/html/rfc5652#section-6.3
|
||||
func (be *CryptFS) pad16(orig []byte) (padded []byte) {
|
||||
oldLen := len(orig)
|
||||
if oldLen == 0 {
|
||||
panic("Padding zero-length string makes no sense")
|
||||
}
|
||||
padLen := aes.BlockSize - oldLen % aes.BlockSize
|
||||
if padLen == 0 {
|
||||
padLen = aes.BlockSize
|
||||
}
|
||||
newLen := oldLen + padLen
|
||||
padded = make([]byte, newLen)
|
||||
copy(padded, orig)
|
||||
padByte := byte(padLen)
|
||||
for i := oldLen; i < newLen; i++ {
|
||||
padded[i] = padByte
|
||||
}
|
||||
return padded
|
||||
}
|
||||
|
||||
// unPad16 - remove padding
|
||||
func (be *CryptFS) unPad16(orig []byte) ([]byte, error) {
|
||||
oldLen := len(orig)
|
||||
if oldLen % aes.BlockSize != 0 {
|
||||
return nil, errors.New("Unaligned size")
|
||||
}
|
||||
// The last byte is always a padding byte
|
||||
padByte := orig[oldLen -1]
|
||||
// The padding byte's value is the padding length
|
||||
padLen := int(padByte)
|
||||
// Padding must be at least 1 byte
|
||||
if padLen <= 0 {
|
||||
return nil, errors.New("Padding cannot be zero-length")
|
||||
}
|
||||
// Larger paddings make no sense
|
||||
if padLen > aes.BlockSize {
|
||||
return nil, errors.New("Padding cannot be larger than 16")
|
||||
}
|
||||
// All padding bytes must be identical
|
||||
for i := oldLen - padLen; i < oldLen; i++ {
|
||||
if orig[i] != padByte {
|
||||
return nil, errors.New(fmt.Sprintf("Padding byte at i=%d is invalid", i))
|
||||
}
|
||||
}
|
||||
newLen := oldLen - padLen
|
||||
// Padding an empty string makes no sense
|
||||
if newLen == 0 {
|
||||
return nil, errors.New("Unpadded length is zero")
|
||||
}
|
||||
return orig[0:newLen], nil
|
||||
}
|
||||
39
cryptfs/intrablock.go
Normal file
39
cryptfs/intrablock.go
Normal file
@ -0,0 +1,39 @@
|
||||
package cryptfs
|
||||
|
||||
// intraBlock identifies a part of a file block
|
||||
type intraBlock struct {
|
||||
BlockNo uint64 // Block number in file
|
||||
Offset uint64 // Offset into block plaintext
|
||||
Length uint64 // Length of data from this block
|
||||
fs *CryptFS
|
||||
}
|
||||
|
||||
// isPartial - is the block partial? This means we have to do read-modify-write.
|
||||
func (ib *intraBlock) IsPartial() bool {
|
||||
if ib.Offset > 0 || ib.Length < ib.fs.plainBS {
|
||||
return true
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// CiphertextRange - get byte range in ciphertext file corresponding to BlockNo
|
||||
// (complete block)
|
||||
func (ib *intraBlock) CiphertextRange() (offset uint64, length uint64) {
|
||||
return ib.BlockNo * ib.fs.cipherBS, ib.fs.cipherBS
|
||||
}
|
||||
|
||||
// PlaintextRange - get byte range in plaintext corresponding to BlockNo
|
||||
// (complete block)
|
||||
func (ib *intraBlock) PlaintextRange() (offset uint64, length uint64) {
|
||||
return ib.BlockNo * ib.fs.plainBS, ib.fs.plainBS
|
||||
}
|
||||
|
||||
// CropBlock - crop a potentially larger plaintext block down to the relevant part
|
||||
func (ib *intraBlock) CropBlock(d []byte) []byte{
|
||||
lenHave := len(d)
|
||||
lenWant := int(ib.Offset+ib.Length)
|
||||
if lenHave < lenWant {
|
||||
return d[ib.Offset:lenHave]
|
||||
}
|
||||
return d[ib.Offset:lenWant]
|
||||
}
|
||||
@ -1,5 +1,16 @@
|
||||
package frontend
|
||||
|
||||
// frontend sits between FUSE and ClueFS
|
||||
// and uses cryptfs for all crypto operations
|
||||
//
|
||||
// cryptfs
|
||||
// ^
|
||||
// |
|
||||
// v
|
||||
// FUSE <-> frontend <-> ClueFS
|
||||
//
|
||||
// This file handles directories
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"github.com/rfjakob/gocryptfs/cryptfs"
|
||||
@ -1,5 +1,16 @@
|
||||
package frontend
|
||||
|
||||
// frontend sits between FUSE and ClueFS
|
||||
// and uses cryptfs for all crypto operations
|
||||
//
|
||||
// cryptfs
|
||||
// ^
|
||||
// |
|
||||
// v
|
||||
// FUSE <-> frontend <-> ClueFS
|
||||
//
|
||||
// This file handles files access
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"github.com/rfjakob/gocryptfs/cryptfs"
|
||||
@ -1,5 +1,16 @@
|
||||
package frontend
|
||||
|
||||
// frontend sits between FUSE and ClueFS
|
||||
// and uses cryptfs for all crypto operations
|
||||
//
|
||||
// cryptfs
|
||||
// ^
|
||||
// |
|
||||
// v
|
||||
// FUSE <-> frontend <-> ClueFS
|
||||
//
|
||||
// This file handles just the root directory
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"github.com/rfjakob/gocryptfs/cryptfs"
|
||||
Loading…
Reference in New Issue
Block a user