greenpass.py

   1 #!/usr/bin/python3
   2
   3 # Copyright 2021 Tobias Girstmair (https://gir.st). Consider this code GPLv3
   4 # licensed.
   5
   6 # pip3 install flynn base45 PyPDF2 pyzbar Pillow
   7 # dnf install zbar || apt install libzbar0
   8
   9 import sys
  10 import glob
  11 import json
  12 import zlib
  13 import flynn
  14 import base45
  15 import PyPDF2
  16 import os
  17 from PIL import Image
  18 from pyzbar import pyzbar
  19 from datetime import datetime
  20 from urllib.request import urlopen
  21
  22 sch = urlopen('https://raw.githubusercontent.com/ehn-dcc-development/ehn-dcc-schema/release/1.3.0/DCC.combined-schema.json')
  23
  24 if len(sys.argv) < 2:
  25     try:
  26         infile = glob.glob("COVID-19-*-*-*.pdf")[0]
  27         print(f"Warning: using file {found}, since not specified\n", file=sys.stderr)
  28     except:
  29         print(f"Usage: {sys.argv[0]} COVID-19-*-*-*.pdf", file=sys.stderr)
  30         print(f"Usage: {sys.argv[0]} QR_CODE.png", file=sys.stderr)
  31         print(f"Usage: {sys.argv[0]} 'HC1:.....'", file=sys.stderr)
  32         sys.exit(1)
  33 else:
  34     if os.path.exists(sys.argv[1]):
  35         infile = sys.argv[1]
  36     else:
  37         infile = None
  38         qr_data_zlib_b45 = sys.argv[1]
  39
  40 if infile:
  41     if open(infile, "rb").read(4) == b"%PDF":
  42         # extract QR code from PDF using hard-coded index, size and bit depth.
  43         # This will only work with the official Austrian green pass PDFs.
  44         pdf=PyPDF2.PdfFileReader(open(infile, "rb"))
  45         qr_img = pdf.getPage(0)['/Resources']['/XObject']['/Im3']
  46         qr_pil = Image.frombytes("1", (400,400), qr_img.getData())
  47     else: # assume image
  48         qr_pil = Image.open(infile)
  49
  50     # decode QR code into raw bytes:
  51     qr_data_zlib_b45 = pyzbar.decode(qr_pil)[0].data
  52
  53 # strip header ('HC1:') and decompress data:
  54 qr_data_zlib = base45.b45decode(qr_data_zlib_b45[4:])
  55 # decompress:
  56 qr_data = zlib.decompress(qr_data_zlib)
  57
  58 # decode cose document:
  59 (_, (headers1, headers2, cbor_data, signature)) = flynn.decoder.loads(qr_data)
  60 # decode cbor-encoded payload:
  61 data = flynn.decoder.loads(cbor_data)
  62
  63 date = lambda ts: datetime.utcfromtimestamp(ts).strftime('%Y-%m-%d %H:%M:%S')
  64 print("QR Code Issuer :", data[1])
  65 print("QR Code Expiry :", date(data[4]))
  66 print("QR Code Generated :", date(data[6]))
  67
  68 glb_schema = json.load(sch)
  69
  70 def annotate(data, schema, level=0):
  71     for key, value in data.items():
  72         description = schema[key].get('title') or schema[key].get('description') or key
  73         description, _, _ = description.partition(' - ')
  74         if type(value) is dict:
  75             print('  '*level, description)
  76             _, _, sch_ref = schema[key]['$ref'].rpartition('/')
  77             annotate(value, glb_schema['$defs'][sch_ref]['properties'], level+1)
  78         elif type(value) is list:
  79             print('  '*level, description)
  80             _, _, sch_ref = schema[key]['items']['$ref'].rpartition('/')
  81             for v in value:
  82                 annotate(v, glb_schema['$defs'][sch_ref]['properties'], level+1)
  83         else: # value is scalar
  84             print('  '*level, description, ':', value)
  85
  86 annotate(data[-260][1], glb_schema['properties'])