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path: root/cryptfs/cryptfs_content.go
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Diffstat (limited to 'cryptfs/cryptfs_content.go')
-rw-r--r--cryptfs/cryptfs_content.go15
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