x509dump-rfc5280.py

#!/usr/bin/env python
# coding: utf-8
#
# This file is part of pyasn1-modules software.
#
# Created by Stanisław Pitucha with asn1ate tool.
# Copyright (c) 2005-2017, Ilya Etingof <etingof@gmail.com>
# License: http://pyasn1.sf.net/license.html
#
# Read ASN.1/PEM X.509 certificates on stdin, parse each into plain text,
# then build substrate from it (using RFC5280)
#
import sys

from pyasn1.codec.der import decoder
from pyasn1.codec.der import encoder

from pyasn1_modules import pem
from pyasn1_modules import rfc5280

if len(sys.argv) != 1:
    print("""Usage:
$ cat CACertificate.pem | %s
$ cat userCertificate.pem | %s""" % (sys.argv[0], sys.argv[0]))
    sys.exit(-1)

certType = rfc5280.Certificate()

certCnt = 0

while 1:
    idx, substrate = pem.readPemBlocksFromFile(
        sys.stdin, ('-----BEGIN CERTIFICATE-----',
                    '-----END CERTIFICATE-----')
    )
    if not substrate:
        break

    cert, rest = decoder.decode(substrate, asn1Spec=certType)

    if rest:
        substrate = substrate[:-len(rest)]

    print(cert.prettyPrint())

    assert encoder.encode(cert) == substrate, 'cert recode fails'

    certCnt += 1

print('*** %s PEM cert(s) de/serialized' % certCnt)