From d4a382ed2f9ee821ce27a2be9f98e5c149d9fdf4 Mon Sep 17 00:00:00 2001
From: Ondrej Mikle <ondrej.mikle@gmail.com>
Date: Fri, 27 Oct 2017 19:23:28 +0200
Subject: [PATCH] Explicit check for signature length before verifying to avoid
 exception

---
 brmdoor_authenticator.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/brmdoor_authenticator.py b/brmdoor_authenticator.py
index 4478bc3..32b3de7 100644
--- a/brmdoor_authenticator.py
+++ b/brmdoor_authenticator.py
@@ -185,6 +185,9 @@ class DesfireEd25519Authenthicator(object):
 
         try:
             ndefSignature = self.nfcReader.readDesfireNDEF()
+            if len(ndefSignature) != 64:
+                logging.error("NDEF signature has wrong length")
+                return None
             if self.signatureCheck(uid_hex.decode("hex"), ndefSignature):
                 return UidRecord(uid_hex, nick)
             else: