Add parameter validation for AES-OFB
diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 4cc4d14..93522e6 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -480,11 +480,16 @@
* will compromise security.
*
* \param ctx The AES context to use for encryption or decryption.
+ * It must be initialized and bound to a key.
* \param length The length of the input data.
* \param iv_off The offset in IV (updated after use).
+ * It must point to a valid \c size_t.
* \param iv The initialization vector (updated after use).
+ * It must be a readable and writeable buffer of 16 Bytes.
* \param input The buffer holding the input data.
+ * It must be readable and of size \p length.
* \param output The buffer holding the output data.
+ * It must be writeable and of size \p length.
*
* \return \c 0 on success.
*/