Regnual update tool: do not allow other than binary formats (upgrade_by_passwd)

Signed-off-by: Szczepan Zalega <szczepan@nitrokey.com>

ChangeLog

@@ -1,3 +1,7 @@
+2017-01-02  Szczepan Zalega <szczepan@nitrokey.com>
+
+	* tool/upgrade_by_passwd.py: Add file extention check.
+
 2017-02-01  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* tool/upgrade_by_passwd.py (main): More verbose messages

tool/upgrade_by_passwd.py

@@ -124,6 +124,9 @@ if __name__ == '__main__':
         passwd = getpass("Admin password: ")
     filename_regnual = sys.argv[1]
     filename_upgrade = sys.argv[2]
+    if not filename_regnual.endswith('bin') or not filename_upgrade.endswith('bin'):
+        print("Both input files must be in binary format (*.bin)!")
+        exit(1)
     f = open(filename_regnual,"rb")
     data_regnual = f.read()
     f.close()