Add basic filename encoding and test on filename

rustcryptfs-lib/src/filename.rs

@@ -1,12 +1,13 @@
 use aes::Aes256;
-use cipher::{block_padding::Pkcs7, Iv, Key, KeyIvInit};
+use cipher::{block_padding::Pkcs7, inout::InOutBufReserved, Iv, Key, KeyIvInit};
-use eme_mode::{DynamicEme};
+use eme_mode::DynamicEme;
 use hkdf::Hkdf;
 
 use crate::error::FilenameDecryptError;
 
-type EmeCipher = DynamicEme<Aes256>;
+pub(crate) type EmeCipher = DynamicEme<Aes256>;
 
+// TODO RENAME
 pub struct FilenameDecoder {
     filename_key: Key<Aes256>,
 }
@@ -31,6 +32,7 @@ impl FilenameDecoder {
     }
 }
 
+// TODO RENAME
 pub struct DirFilenameDecoder<'a, 'b> {
     filename_key: &'a Key<EmeCipher>,
     iv: &'b Iv<EmeCipher>,
@@ -40,11 +42,64 @@ impl<'a, 'b> DirFilenameDecoder<'a, 'b> {
     pub fn decode_filename(&self, name: &str) -> Result<String, FilenameDecryptError> {
         let cipher = EmeCipher::new(self.filename_key, self.iv);
 
-        let mut filename = base64::decode_config(name, base64::URL_SAFE)?;
+        let mut filename = base64::decode_config(name, base64::URL_SAFE_NO_PAD)?;
         let filename_decoded = cipher
             .decrypt_padded_mut::<Pkcs7>(&mut filename)
             .map_err(|_| FilenameDecryptError::DecryptError())?;
 
         Ok(String::from_utf8_lossy(filename_decoded).to_string())
     }
+
+    pub fn encrypt_filename(&self, plain_text_name: &str) -> Result<String, FilenameDecryptError> {
+        let mut cipher = EmeCipher::new(self.filename_key, self.iv);
+        let mut res = [0u8; 2048];
+
+        let filename_encrypted = cipher
+            .encrypt_padded_inout_mut::<Pkcs7>(
+                InOutBufReserved::from_slices(plain_text_name.as_bytes(), &mut res).unwrap(),
+            )
+            .map_err(|_| FilenameDecryptError::DecryptError())?; // TODO RENAME ERROR
+
+        // TODO LONG FILENAME
+
+        Ok(base64::encode_config(
+            filename_encrypted,
+            base64::URL_SAFE_NO_PAD,
+        ))
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::FilenameDecoder;
+
+    #[test]
+    fn test_encrypt() {
+        let master_key = base64::decode("9gtUW9XiiefEgEXEkbONI6rnUsd2yh5UZZLG0V8Bxgk=").unwrap();
+        let dir_iv = base64::decode("6ysCeWOp2euF1x39gth8KQ==").unwrap();
+
+        let decoder = FilenameDecoder::new(&master_key).expect("Failed to get file decoder");
+        let dir_decoder = decoder.get_decoder_for_dir(&dir_iv);
+
+        let encoded = dir_decoder
+            .encrypt_filename("7.mp4")
+            .expect("Failed to encrypt filename");
+
+        assert_eq!(encoded, "vTBajRt-yCpxB7Sly0E7lQ");
+    }
+
+    #[test]
+    fn test_decrypt() {
+        let master_key = base64::decode("9gtUW9XiiefEgEXEkbONI6rnUsd2yh5UZZLG0V8Bxgk=").unwrap();
+        let dir_iv = base64::decode("6ysCeWOp2euF1x39gth8KQ==").unwrap();
+
+        let decoder = FilenameDecoder::new(&master_key).expect("Failed to get file decoder");
+        let dir_decoder = decoder.get_decoder_for_dir(&dir_iv);
+
+        let decrypted = dir_decoder
+            .decode_filename("vTBajRt-yCpxB7Sly0E7lQ")
+            .expect("Failed to decrypt filename");
+
+        assert_eq!(decrypted, "7.mp4");
+    }
 }