diff options
Diffstat (limited to 'cryptfs/cryptfs_content.go')
| -rw-r--r-- | cryptfs/cryptfs_content.go | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/cryptfs/cryptfs_content.go b/cryptfs/cryptfs_content.go index 6444b8b..cb309ea 100644 --- a/cryptfs/cryptfs_content.go +++ b/cryptfs/cryptfs_content.go @@ -3,6 +3,7 @@ package cryptfs // File content encryption / decryption import ( + "encoding/binary" "bytes" "crypto/cipher" "crypto/md5" @@ -29,18 +30,19 @@ type CryptFile struct { } // DecryptBlocks - Decrypt a number of blocks -func (be *CryptFS) DecryptBlocks(ciphertext []byte) ([]byte, error) { +func (be *CryptFS) DecryptBlocks(ciphertext []byte, firstBlockNo uint64) ([]byte, error) { cBuf := bytes.NewBuffer(ciphertext) var err error var pBuf bytes.Buffer for cBuf.Len() > 0 { cBlock := cBuf.Next(int(be.cipherBS)) var pBlock []byte - pBlock, err = be.DecryptBlock(cBlock) + pBlock, err = be.DecryptBlock(cBlock, firstBlockNo) if err != nil { break } pBuf.Write(pBlock) + firstBlockNo++ } return pBuf.Bytes(), err } @@ -49,7 +51,7 @@ func (be *CryptFS) DecryptBlocks(ciphertext []byte) ([]byte, error) { // // Corner case: A full-sized block of all-zero ciphertext bytes is translated // to an all-zero plaintext block, i.e. file hole passtrough. -func (be *CryptFS) DecryptBlock(ciphertext []byte) ([]byte, error) { +func (be *CryptFS) DecryptBlock(ciphertext []byte, blockNo uint64) ([]byte, error) { // Empty block? if len(ciphertext) == 0 { @@ -74,7 +76,8 @@ func (be *CryptFS) DecryptBlock(ciphertext []byte) ([]byte, error) { // Decrypt var plaintext []byte - + aData := make([]byte, 8) + binary.BigEndian.PutUint64(aData, blockNo) plaintext, err := be.gcm.Open(plaintext, nonce, ciphertext, nil) if err != nil { @@ -87,7 +90,7 @@ func (be *CryptFS) DecryptBlock(ciphertext []byte) ([]byte, error) { } // encryptBlock - Encrypt and add MAC using GCM -func (be *CryptFS) EncryptBlock(plaintext []byte) []byte { +func (be *CryptFS) EncryptBlock(plaintext []byte, blockNo uint64) []byte { // Empty block? if len(plaintext) == 0 { @@ -98,6 +101,8 @@ func (be *CryptFS) EncryptBlock(plaintext []byte) []byte { nonce := gcmNonce.Get() // Encrypt plaintext and append to nonce + aData := make([]byte, 8) + binary.BigEndian.PutUint64(aData, blockNo) ciphertext := be.gcm.Seal(nonce, nonce, plaintext, nil) return ciphertext |