diff options
Diffstat (limited to 'cryptfs/cryptfs_content.go')
| -rw-r--r-- | cryptfs/cryptfs_content.go | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/cryptfs/cryptfs_content.go b/cryptfs/cryptfs_content.go index 0494b69..e42011a 100644 --- a/cryptfs/cryptfs_content.go +++ b/cryptfs/cryptfs_content.go @@ -32,6 +32,9 @@ func (be *CryptFS) DecryptBlocks(ciphertext []byte) ([]byte, error) { } // DecryptBlock - Verify and decrypt GCM block +// +// 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) { // Empty block? @@ -39,6 +42,12 @@ func (be *CryptFS) DecryptBlock(ciphertext []byte) ([]byte, error) { return ciphertext, nil } + // All-zero block? + if bytes.Equal(ciphertext, be.allZeroBlock) { + Debug.Printf("DecryptBlock: file hole encountered\n") + return make([]byte, be.plainBS), nil + } + if len(ciphertext) < NONCE_LEN { Warn.Printf("decryptBlock: Block is too short: %d bytes\n", len(ciphertext)) return nil, errors.New("Block is too short") |