From 78ae0f8c5975994f8920c6bf18c44ec878dcfbcb Mon Sep 17 00:00:00 2001
From: Dag Heyman <dag@yubico.com>
Date: Thu, 3 Aug 2017 12:24:32 +0200
Subject: [PATCH] Add error message for too large keys in slot mode

Closes #171
---
 py/yubikey.py             |  3 +--
 qml/AddCredentialSlot.qml | 11 +++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/py/yubikey.py b/py/yubikey.py
index 2e6da5fe..d923dcbd 100644
--- a/py/yubikey.py
+++ b/py/yubikey.py
@@ -191,8 +191,7 @@ class Controller(object):
         if len(key) > 64:  # Keys longer than 64 bytes are hashed.
             key = hashlib.sha1(key).digest()
         if len(key) > 20:
-            raise ValueError(
-                'YubiKey Slots cannot handle TOTP keys over 20 bytes.')
+            return 'Over 20 bytes'
         key += b'\x00' * (20 - len(key))  # Keys must be padded to 20 bytes.
         dev.driver.program_chalresp(int(slot), key, touch)
 
diff --git a/qml/AddCredentialSlot.qml b/qml/AddCredentialSlot.qml
index 4d2da7e6..56e8f4da 100644
--- a/qml/AddCredentialSlot.qml
+++ b/qml/AddCredentialSlot.qml
@@ -115,6 +115,14 @@ DefaultDialog {
         standardButtons: StandardButton.Ok
     }
 
+    MessageDialog {
+        id: tooLargeKeyError
+        icon: StandardIcon.Critical
+        title: qsTr("Too large key")
+        text: qsTr("YubiKey Slots cannot handle TOTP keys over 20 bytes.")
+        standardButtons: StandardButton.Ok
+    }
+
     MessageDialog {
         id: confirmOverWrite
         icon: StandardIcon.Warning
@@ -160,6 +168,9 @@ DefaultDialog {
                                      if (error === 'Incorrect padding') {
                                          paddingError.open()
                                      }
+                                     if (error === 'Over 20 bytes') {
+                                         tooLargeKeyError.open()
+                                     }
                                      if (error) {
                                          console.log(error)
                                      }