From cfe19b55a1662686db0e3b6dc2238eb8763fc763 Mon Sep 17 00:00:00 2001
From: Ondrej Mikle <ondrej.mikle@gmail.com>
Date: Fri, 27 Oct 2017 19:56:43 +0200
Subject: [PATCH] Make the signature wrapped in JSON object to be able to
 extend structure later

---
 brmdoor_authenticator.py        | 15 +++++++++++++--
 write_signed_ndef_on_desfire.py |  4 +++-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/brmdoor_authenticator.py b/brmdoor_authenticator.py
index 32b3de7..5fefeee 100644
--- a/brmdoor_authenticator.py
+++ b/brmdoor_authenticator.py
@@ -3,6 +3,7 @@ import sqlite3
 import hmac
 import hashlib
 import logging
+import json
 
 import axolotl_curve25519 as curve
 
@@ -184,7 +185,8 @@ class DesfireEd25519Authenthicator(object):
         nick = record[0]
 
         try:
-            ndefSignature = self.nfcReader.readDesfireNDEF()
+            ndefJson = json.loads(self.nfcReader.readDesfireNDEF())
+            ndefSignature = ndefJson["brmdoorSignature"].decode("hex")
             if len(ndefSignature) != 64:
                 logging.error("NDEF signature has wrong length")
                 return None
@@ -194,7 +196,16 @@ class DesfireEd25519Authenthicator(object):
                 logging.info("Signature check failed for Desfire NDEF for UID %s", uid_hex)
                 return None
         except NFCError, e:
-            logging.info("Desfire read NDEF failed: %s" % e.what())
+            logging.error("Desfire read NDEF failed: %s", e.what())
+            return None
+        except TypeError, e:
+            logging.error("Could not decode signature from JSON: %s", e)
+            return None
+        except ValueError, e:
+            logging.error("Could not decode JSON from NDEF: %s", e)
+            return None
+        except KeyError, e:
+            logging.error("Missing signature in JSON: %s", e)
             return None
 
     def shutdown(self):
diff --git a/write_signed_ndef_on_desfire.py b/write_signed_ndef_on_desfire.py
index 7e0a1be..1f11752 100755
--- a/write_signed_ndef_on_desfire.py
+++ b/write_signed_ndef_on_desfire.py
@@ -27,7 +27,9 @@ try:
     print "Got UID %s" % uid_hex
     signature = signUid(key, uid_hex.decode("hex"))
     (tempFd, tempFname) = tempfile.mkstemp(dir="/tmp")
-    os.write(tempFd, signature)
+    signatureJson = '{"brmdoorSignature": "%s"}' % signature.encode("hex")
+    print "Writing signature JSON:", signatureJson
+    os.write(tempFd, signatureJson)
     os.close(tempFd)
     print "Wrote signature into %s" % tempFname
 except NFCError, e: