Check the size of the message before decrypting it.

[rup.git] / src / crypto.rs

diff --git a/src/crypto.rs b/src/crypto.rs
index 7e707d0..caf34f7 100644 (file)
--- a/src/crypto.rs
+++ b/src/crypto.rs
@@ -19,6 +19,7 @@ pub enum EncryptError {
 pub enum DecryptError {\r
     KeyError(KeyError),\r
     WrongMessageVersion,\r
+    MessageToShort,\r
     UnableToDecodeBase64Message,\r
     UnableToDecrypt,\r
     UnableToDecodeMessageAsUTF8String,\r
@@ -27,27 +28,24 @@ pub enum DecryptError {
 \r
 fn decode_key(key: &str) -> Result<Vec<u8>, KeyError> {\r
     match base64::decode(key) {\r
-        Ok(k) => if k.len() != 16 { return Err(KeyError::WrongKeyLength) } else { Ok(k) },\r
+        Ok(k) => if k.len() != 16 { Err(KeyError::WrongKeyLength) } else { Ok(k) },\r
         Err(_e) => Err(KeyError::UnableToDecodeBase64Key)\r
     }\r
 }\r
 \r
 /// Encrypt the given text with the given key. The key length must be 128 bits encoded in base64.\r
-/// Ouput format:\r
-/// Format "1" + base_64(<IV> + <hash(message)> + <aes(message)>)\r
+/// Ouput format: "1" + base_64(<IV> + <hash(message)> + <aes(message)>)\r
 /// IV: 16 bytes randomized.\r
 /// Mode : CBC.\r
 pub fn encrypt(key: &str, plain_text: &str) -> Result<String, EncryptError> {\r
-    let key_as_bytes = decode_key(key).map_err(|e| EncryptError::KeyError(e))?;\r
+    let key_as_bytes = decode_key(key).map_err(EncryptError::KeyError)?;\r
 \r
     let text_as_bytes = plain_text.as_bytes();\r
     let iv = rand::thread_rng().gen::<[u8; 16]>();\r
 \r
     let cipher_text =\r
-        match symm::encrypt(symm::Cipher::aes_128_cbc(), &key_as_bytes, Some(&iv), text_as_bytes) {\r
-            Ok(t) => t,\r
-            Err(_e) => return Err(EncryptError::UnableToEncrypt)\r
-        };\r
+        symm::encrypt(symm::Cipher::aes_128_cbc(), &key_as_bytes, Some(&iv), text_as_bytes)\r
+            .map_err(|_e| EncryptError::UnableToEncrypt)?;\r
 \r
     let hash_text = sha256(&text_as_bytes);\r
 \r
@@ -59,9 +57,10 @@ pub fn encrypt(key: &str, plain_text: &str) -> Result<String, EncryptError> {
     Ok(String::from("1") + &base64::encode(&result))\r
 }\r
 \r
-/// TODO: return a Result<string, DecryptError>\r
+/// Decrypt the given text with the given key. The key length must be 128 bits encoded in base64.\r
+/// Input format: "1" + base_64(<IV> + <hash(message)> + <aes(message)>)\r
 pub fn decrypt(key: &str, cipher_text: &str) -> Result<String, DecryptError> {\r
-    let key_as_bytes = decode_key(key).map_err(|e| DecryptError::KeyError(e))?;\r
+    let key_as_bytes = decode_key(key).map_err(DecryptError::KeyError)?;\r
 \r
     // Can't decrypt a message with the wrong version.\r
     if !cipher_text.starts_with(consts::CURRENT_MESSAGE_VERSION) { return Err(DecryptError::WrongMessageVersion) }\r
@@ -70,6 +69,8 @@ pub fn decrypt(key: &str, cipher_text: &str) -> Result<String, DecryptError> {
         base64::decode(&cipher_text.as_bytes()[consts::CURRENT_MESSAGE_VERSION.as_bytes().len()..])\r
             .map_err(|_e| DecryptError::UnableToDecodeBase64Message)?;\r
 \r
+    if cipher_text_bytes.len() <= 48 { return Err(DecryptError::MessageToShort) }\r
+\r
     let iv = &cipher_text_bytes[0..16];\r
     let hash = &cipher_text_bytes[16..48];\r
     let encrypted_message = &cipher_text_bytes[48..];\r