Added function to save an encrypted version of the messenger.

Also added some tests.

1 files changed, 69 insertions, 0 deletions

diff --git a/toxcore/Messenger.c b/toxcore/Messenger.c
index b3c8fb40..78c83519 100644
--- a/toxcore/Messenger.c
+++ b/toxcore/Messenger.c
@@ -2264,6 +2264,75 @@ int messenger_load(Messenger *m, uint8_t *data, uint32_t length)
         return -1;
 }
 
+/* return the size of data to pass to messenger_save_encrypted(...)
+ *
+ */
+uint32_t messenger_size_encrypted(Messenger *m)
+{
+    return messenger_size(m) + crypto_secretbox_MACBYTES + crypto_secretbox_NONCEBYTES;
+}
+
+/* Save the messenger, encrypting the data with key of length key_length
+ *
+ * return 0 on success.
+ * return -1 on failure.
+ */
+int messenger_save_encrypted(Messenger *m, uint8_t *data, uint8_t *key, uint16_t key_length)
+{
+    uint32_t m_size = messenger_size(m);
+    uint8_t *plain_messenger = malloc(m_size);
+
+    if (plain_messenger == NULL)
+        return -1;
+
+    messenger_save(m, plain_messenger);
+
+    /* Hash the key with SHA256 to get a 32byte key. */
+    uint8_t hash[crypto_hash_sha256_BYTES];
+    crypto_hash_sha256(hash, key, key_length);
+    random_nonce(data);
+    encrypt_data_symmetric(hash, data, plain_messenger, m_size, data + crypto_secretbox_NONCEBYTES);
+
+    memset(plain_messenger, 0, m_size);
+    free(plain_messenger);
+    memset(hash, 0, crypto_hash_sha256_BYTES);
+    return 0;
+}
+
+/* Load the messenger from data of size length encrypted with key of key_length.
+ *
+ * return 0 on success.
+ * return -1 on failure.
+ */
+int messenger_load_encrypted(Messenger *m, uint8_t *data, uint32_t length, uint8_t *key, uint16_t key_length)
+{
+    if (length <= crypto_secretbox_MACBYTES + crypto_secretbox_NONCEBYTES)
+        return -1;
+
+    uint8_t *plain_messenger = malloc(length);
+
+    if (plain_messenger == NULL)
+        return -1;
+
+    /* Hash the key with SHA256 to get a 32byte key. */
+    uint8_t hash[crypto_hash_sha256_BYTES];
+    crypto_hash_sha256(hash, key, key_length);
+    int len = decrypt_data_symmetric(hash, data, data + crypto_secretbox_NONCEBYTES, length - crypto_secretbox_NONCEBYTES,
+                                     plain_messenger);
+    int ret;
+
+    if ((uint32_t)len == length - crypto_secretbox_NONCEBYTES - crypto_secretbox_MACBYTES) {
+        ret = messenger_load(m, plain_messenger, length - crypto_secretbox_NONCEBYTES - crypto_secretbox_MACBYTES);
+    } else {
+        ret = -1;
+    }
+
+    memset(plain_messenger, 0, length);
+    free(plain_messenger);
+    memset(hash, 0, crypto_hash_sha256_BYTES);
+    return ret;
+}
+
 /* Return the number of friends in the instance m.
  * You should use this to determine how much memory to allocate
  * for copy_friendlist. */