#!/usr/bin/env python

"""
Run the OpenDNSSEC libhsm/check/hsmcheck tool with Cryptech PKCS #11,
using DNSpython to verify the DNSSEC data produced by"hsmcheck -s".

This script knows far too much about the output generated by hsmcheck,
but what were you expecting from an ad hoc test tool that gets its
input by screen scraping the output of another ad hoc test tool?
"""

# Author: Rob Austein
# Copyright (c) 2015, SUNET
# 
# Redistribution and use in source and binary forms, with or 
# without modification, are permitted provided that the following 
# conditions are met: 
# 
# 1. Redistributions of source code must retain the above copyright 
#    notice, this list of conditions and the following disclaimer. 
# 
# 2. Redistributions in binary form must reproduce the above copyright 
#    notice, this list of conditions and the following disclaimer in 
#    the documentation and/or other materials provided with the 
#    distribution. 
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 
# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 
# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
# STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

import os
import sys

from argparse import ArgumentParser, ArgumentDefaultsHelpFormatter, FileType as ArgumentFileType
from tempfile import NamedTemporaryFile
from subprocess import check_call, check_output
from xml.etree.ElementTree import ElementTree, Element, SubElement


def write_config():
  """
  Write hsmcheck configuration file.
  """

  e = Element("Configuration")
  r = SubElement(e, "RepositoryList")
  r = SubElement(r, "Repository", name = "default")
  SubElement(r, "Module").text = args.driver
  SubElement(r, "TokenLabel").text = args.token_label
  SubElement(r, "PIN").text = args.pin
  ElementTree(e).write(args.write_config)
  args.write_config.flush()  


def hsmcheck(flag):
  """
  Run hsmcheck program with appropriate options and verbosity.
  """

  assert flag in "rgsd"
  cmd = (args.hsmcheck_binary, "-c", args.write_config.name, "-" + flag)
  if args.verbose:
    sys.stdout.write("Running: %s\n" % " ".join(cmd))
  if flag == "s":
    text = check_output(cmd)
    sys.stdout.write(text)
    if not args.no_dnssec:
      check_dnssec(text)
  else:
    check_call(cmd)


def check_dnssec(text):
  """
  Use DNSPython to attempt DNSSEC validation on "hsmcheck -s" output.

  This requires the DNSPython toolkit, which in turn requires
  PyCrypto; ECDSA support (not yet tested) requires a third package.
  On Debian-family Linux, you can install these with:
  
      sudo apt-get install python-dnspython python-crypto python-ecdsa

  Equivalent packages exist for other platforms.
  """

  try:
    from dns.exception import DNSException
    import dns.dnssec
    import dns.rrset
    import Crypto.PublicKey.RSA
    #import ecdsa.ecdsa
  except ImportError:
    sys.exit("Problem importing DNSPython or supporting crypto packages, are they installed?")

  wired_ttl     = "3600"
  wired_rdclass = "IN"

  rrs = {}

  for line in text.splitlines():

    try:
      name, ttl, rdclass, rdtype, rdata = line.split(None, 4)
    except ValueError:
      continue

    if ttl != wired_ttl or rdclass != wired_rdclass:
      continue

    try:
      rrs[name, rdtype].append(rdata)
    except KeyError:
      rrs[name, rdtype] = [rdata]

  # Done parsing.  We expect to have seen an A RRset, an RRSIG of that
  # A RRset, and the DNSKEY that we'll need to verify the RRSIG.

  if len(rrs) != 3:
    sys.exit("Expected two RRsets and an RRSIG, got %r" % rrs)

  rrs = dict((rdtype, dns.rrset.from_text_list(name, int(wired_ttl), wired_rdclass, rdtype, rrs[name, rdtype]))
                for name, rdtype in rrs)

  try:
    dns.dnssec.validate(rrs["A"], rrs["RRSIG"], { rrs["DNSKEY"].name : rrs["DNSKEY"] })
  except DNSException, e:
    sys.exit("DNSSEC verification failed: %s" % e)

  sys.stdout.write("\nDNSSEC verification successful!\n\n")


# Main program.

try:
  default_config   = NamedTemporaryFile()
  default_hsmcheck = os.getenv("HSMCHECK", "hsmcheck")
  default_driver   = os.getenv("PKCS11_DRIVER",
                               os.path.realpath(os.path.join(os.path.dirname(sys.argv[0]), "..", "libpkcs11.so")))

  parser = ArgumentParser(description = __doc__, formatter_class = ArgumentDefaultsHelpFormatter)
  one_of = parser.add_mutually_exclusive_group()
  one_of.add_argument("-a", "--all", "--rgsd", const = "rgsd", dest = "test", action = "store_const", help = "run all tests")
  one_of.add_argument("-r", "--random",   const = "r", dest = "test", action = "store_const", help = "just test random numbers")
  one_of.add_argument("-g", "--generate", const = "g", dest = "test", action = "store_const", help = "just test key generation")
  one_of.add_argument("-s", "--sign",     const = "s", dest = "test", action = "store_const", help = "just test DNSSEC-signature")
  one_of.add_argument("-d", "--delete",   const = "d", dest = "test", action = "store_const", help = "just delete key")
  parser.add_argument("-b", "--hsmcheck-binary",  default = default_hsmcheck, help = "location of hsmcheck program")
  parser.add_argument("-p", "--pin",              default = "12345",          help = "HSM PIN to use for tests")
  parser.add_argument("-t", "--token-label",      default = "Cryptech Token", help = "PKCS #11 label of Cryptech token")
  parser.add_argument("-n", "--no-dnssec",        action = "store_true",      help = "do not attempt DNSSEC validation")
  parser.add_argument("-v", "--verbose",          action = "store_true",      help = "bark more")
  parser.add_argument("-D", "--driver",           default = default_driver,   help = "location of PKCS #11 driver")
  parser.add_argument("-w", "--write-config",     default = default_config,   help = "write generated configuration to this file",
                      type = ArgumentFileType("w"))
  parser.add_argument("--debug",                  action = "store_true",      help = "debug this script")
  parser.set_defaults(test = "rgsd")
  args = parser.parse_args()

  try:
    write_config()
    for flag in args.test:
      hsmcheck(flag)

  except Exception as e:
    if args.debug:
      raise
    sys.exit("Failed: %s" % e)

finally:
  default_config.close()