#!/usr/bin/python3
#
# script to create certificate use for test
#
#    Copyright (C) 2017  AleaJactaEst
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

"""
Generate all certificates
   CA certificate (emulate CA certificate)
   Appli certification (our global certificate, use to sign our key)
   Server certificate (our key & certificate for server side)
   Client certificate (our key & certificate for server side)

 CA
   \
    Apppli
   /      \
 Server  Client

Example command to generate all certificate :
    create_certificate.py  --show-log-console --log debug
"""

import argparse
import logging
import logging.config
import os
import stat
import subprocess
import sys


class Certificate:
    def __init__(self,
                 openssl,
                 workdir_cert_ca,
                 workdir_cert_appli,
                 passca='OpenNelCA9439',
                 passappli='OpenNelAPPLI1097',
                 countryName='FR',
                 stateOrProvinceName='France',
                 localityName='Paris',
                 organizationName='khanat',
                 commonName='khanat.org',
                 sizeCa = 4096,
                 sizeAppli = 4096,
                 sizeChild = 2048):
        self.workdir_cert_ca = os.path.abspath(workdir_cert_ca)
        self.workdir_cert_appli = os.path.abspath(workdir_cert_appli)
        self.openssl = openssl
        self.passca = passca
        self.passappli = passappli
        self.countryName = countryName
        self.stateOrProvinceName = stateOrProvinceName
        self.localityName = localityName
        self.organizationName = organizationName
        self.commonName = commonName
        self.configca = os.path.join(self.workdir_cert_ca, 'openssl.cnf')
        self.configappli = os.path.join(self.workdir_cert_appli, 'openssl.cnf')
        self.sizeCa = sizeCa
        self.sizeAppli = sizeAppli
        self.sizeChild = sizeChild

    def directory_create(self, dirpath):
        if not dir:
            raise ValueError
        if not os.path.exists(dirpath):
            os.makedirs(dirpath)

    def SendCommandOpenssl(self, args):
        command = '%s %s' % (self.openssl, args)
        logging.debug("command:%s" % command)
        code = subprocess.call(command.split(), stdout=sys.stdout,
                     stderr=sys.stderr)
        if code != 0:
            logging.error("Command '%s' return code:%d" % (command, code))
            exit(code)

    def writeConfigOpenssl(self, config, dirpath, certfile, keyfile):
        with open(config,  'w') as f:
            f.write('[ ca ]\n'
                    'default_ca = CA_default\n'
                    '\n[ CA_default ]\n'
                    'dir = %s\n'
                    'certs = $dir/certs\n'
                    'crl_dir = $dir/crl\n'
                    'database = $dir/index.txt\n'
                    'new_certs_dir = $dir/newcerts\n'
                    'certificate = $dir/certs/%s\n'
                    'serial = $dir/serial\n'
                    'crlnumber = $dir/crlnumber\n'
                    'crl = $dir/crl/%s\n'
                    'private_key = $dir/private/%s\n'
                    'RANDFILE = $dir/private/.rand\n'
                    'name_opt = ca_default\n'
                    'cert_opt = ca_default\n'
                    'default_days = 390\n'
                    'default_crl_days = 30\n'
                    'default_md = sha256\n'
                    'preserve = no\n'
                    'policy = policy_match\n'
                    'crl_extensions = crl_ext\n'
                    'unique_subject = no\n'
                    '\n[ policy_match ]\n'
                    'countryName = match\n'
                    'stateOrProvinceName = match\n'
                    'organizationName = match\n'
                    'organizationalUnitName = optional\n'
                    'commonName = supplied\n'
                    'emailAddress = optional\n'
                    '\n[ req ]\n'
                    'default_bits = 2048\n'
                    'distinguished_name = req_distinguished_name\n'
                    'x509_extensions = v3_ca\n'
                    'string_mask = utf8only\n'
                    'unique_subject = no\n'
                    '\n[ server_cert ]\n'
                    'basicConstraints=CA:false\n'
                    'nsComment = "OpenSSL Generated Certificate"\n'
                    'subjectKeyIdentifier=hash\n'
                    'authorityKeyIdentifier=keyid,issuer:always\n'
                    'keyUsage = critical, digitalSignature, keyEncipherment\n'
                    'nsCertType = server\n'
                    '\n[ client_cert ]\n'
                    'basicConstraints=CA:false\n'
                    'nsComment = "OpenSSL Generated Certificate"\n'
                    'subjectKeyIdentifier=hash\n'
                    'authorityKeyIdentifier=keyid:always,issuer\n'
                    'keyUsage = critical, nonRepudiation, digitalSignature, keyEncipherment\n'
                    'nsCertType = client\n'
                    '\n[ v3_ca ]\n'
                    'basicConstraints=critical, CA:true\n'
                    'nsComment = "OpenSSL Generated Certificate"\n'
                    'subjectKeyIdentifier=hash\n'
                    'authorityKeyIdentifier=keyid:always,issuer\n'
                    'keyUsage = critical, digitalSignature, cRLSign, keyCertSign\n'
                    '\n[ v3_application_ca ]\n'
                    'basicConstraints=critical, CA:true, pathlen:0\n'
                    'nsComment = "OpenSSL Generated Certificate"\n'
                    'subjectKeyIdentifier=hash\n'
                    'authorityKeyIdentifier=keyid:always,issuer\n'
                    'keyUsage = critical, digitalSignature, cRLSign, keyCertSign\n'
                    '\n[ req_distinguished_name ]\n'
                    'countryName = Country Name (2 letter code)\n'
                    'countryName_default = FR\n'
                    'countryName_min = 2\n'
                    'countryName_max = 2\n'
                    'stateOrProvinceName = State or Province Name (full name)\n'
                    'stateOrProvinceName_default = France\n'
                    'localityName = Locality Name (eg, city)\n'
                    '0.organizationName = Organization Name (eg, company)\n'
                    '0.organizationName_default = Khanat\n'
                    'organizationalUnitName = Organizational Unit Name (eg, section)\n'
                    'commonName = Common Name (e.g. server FQDN or YOUR name)\n'
                    'commonName_max = 64\n'
                    'emailAddress = Email Address\n'
                    'emailAddress_max = 64\n'
                    '\n[ crl_ext ]\n'
                    'authorityKeyIdentifier=keyid:always\n'
                    % (dirpath, certfile, 'cacrl.pem',  keyfile))

    def createCACertificate(self):
        logging.info("Create CA Certificate")
        # Create directory
        certfilename = 'cacert.pem'
        keyfilename = 'cakey.pem'
        self.directory_create(self.workdir_cert_ca)
        self.directory_create(os.path.join(self.workdir_cert_ca, 'certs'))
        private=os.path.join(self.workdir_cert_ca, 'private')
        self.directory_create(private)
        os.chmod(private, stat.S_IEXEC | stat.S_IWUSR | stat.S_IRUSR)
        self.directory_create(os.path.join(self.workdir_cert_ca, 'crl'))
        self.directory_create(os.path.join(self.workdir_cert_ca, 'newcerts'))
        # Create files use in CA
        index = os.path.join(self.workdir_cert_ca, 'index.txt')
        with open(index, 'w') as f:
            f.write('')
        serial = os.path.join(self.workdir_cert_ca, 'serial')
        with open(serial,  'w') as f:
            f.write('10')
        # Create configuration
        self.writeConfigOpenssl(self.configca, self.workdir_cert_ca, certfilename, keyfilename)
        # Create private key for our CA
        keyfile = os.path.join(self.workdir_cert_ca, 'private', keyfilename)
        self.SendCommandOpenssl('genrsa -aes256 -out %s -passout pass:%s %d' % (keyfile, self.passca, self.sizeCa))
        os.chmod(keyfile, stat.S_IEXEC | stat.S_IWUSR | stat.S_IRUSR)
        # Create certificate for our CA
        certfile = os.path.join(self.workdir_cert_ca, 'certs', certfilename)
        self.SendCommandOpenssl('req '
                                '-config %s '
                                '-key %s '
                                '-passin pass:%s '
                                '-new '
                                '-x509 '
                                '-days 390 '
                                '-sha256 '
                                '-extensions v3_ca '
                                '-out %s '
                                '-subj /C=%s/ST=%s/L=%s/O=%s/CN=%s' % (self.configca,
                                                                       keyfile,
                                                                       self.passca,
                                                                       certfile,
                                                                       self.countryName,
                                                                       self.stateOrProvinceName,
                                                                       self.localityName,
                                                                       self.organizationName,
                                                                       self.commonName))
        os.chmod(certfile, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)

        # Check certificate
        self.SendCommandOpenssl('x509 -noout -text -in %s' % certfile)

    def createApplicationCertificate(self):
        logging.info("Create Application Certificate")
        certfilename = 'applicert.pem'
        csrfilename = 'applicsr.pem'
        keyfilename = 'applikey.pem'
        # Create directory
        self.directory_create(self.workdir_cert_appli)
        self.directory_create(os.path.join(self.workdir_cert_appli, 'certs'))
        private=os.path.join(self.workdir_cert_appli, 'private')
        self.directory_create(private)
        os.chmod(private, stat.S_IEXEC | stat.S_IWUSR | stat.S_IRUSR)
        self.directory_create(os.path.join(self.workdir_cert_appli, 'crl'))
        self.directory_create(os.path.join(self.workdir_cert_appli, 'newcerts'))
        self.directory_create(os.path.join(self.workdir_cert_appli, 'csr'))
        # Create files use in CA
        index = os.path.join(self.workdir_cert_appli, 'index.txt')
        with open(index, 'w') as f:
            f.write('')
        serial = os.path.join(self.workdir_cert_appli, 'serial')
        with open(serial,  'w') as f:
            f.write('10')
        serial = os.path.join(self.workdir_cert_appli, 'crlnumber')
        with open(serial,  'w') as f:
            f.write('10')
        # Create configuration
        self.writeConfigOpenssl(self.configappli, self.workdir_cert_appli, certfilename, keyfilename)
        # Create private key for our Application
        keyfile = os.path.join(self.workdir_cert_appli, 'private', keyfilename)
        self.SendCommandOpenssl('genrsa -aes256 -out %s -passout pass:%s %d' % (keyfile,
                                                                                self.passappli,
                                                                                self.sizeAppli))
        os.chmod(keyfile, stat.S_IEXEC | stat.S_IWUSR | stat.S_IRUSR)
        # Create certificate for our CA
        csrfile = os.path.join(self.workdir_cert_appli, 'csr', csrfilename)
        self.SendCommandOpenssl('req '
                                '-config %s '
                                '-new '
                                '-sha256 '
                                '-passin pass:%s '
                                '-key %s '
                                '-out %s '
                                '-subj /C=%s/ST=%s/L=%s/O=%s/CN=%s' % (self.configappli,
                                                                       self.passappli,
                                                                       keyfile,
                                                                       csrfile,
                                                                       self.countryName,
                                                                       self.stateOrProvinceName,
                                                                       self.localityName,
                                                                       self.organizationName,
                                                                       self.commonName))
        os.chmod(csrfile, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)
        certfile = os.path.join(self.workdir_cert_appli, 'certs', certfilename)
        # Sign certificate
        self.SendCommandOpenssl('ca '
                                '-config %s '
                                '-extensions v3_application_ca '
                                '-days 390 '
                                '-notext '
                                '-md sha256 '
                                '-passin pass:%s '
                                '-in %s '
                                '-batch '
                                '-out %s ' % (self.configca,
                                              self.passca,
                                              csrfile,
                                              certfile))
        os.chmod(csrfile, stat.S_IRUSR | stat.S_IRGRP | stat.S_IROTH)
        self.SendCommandOpenssl('x509 -noout -text -in %s' % certfile)
        certcafilename = os.path.join(self.workdir_cert_ca, 'certs', 'cacert.pem')
        self.SendCommandOpenssl('verify -CAfile %s %s' % (certcafilename, certfile))
        # concat applicert & cacert
        cachainfile = os.path.join(self.workdir_cert_appli, 'certs', 'cachaincert.pem')
        with open(cachainfile, 'w') as outfp:
            with open(certfile, 'r') as infp:
                outfp.write(infp.read())
            with open(certcafilename,  'r') as infp:
                outfp.write(infp.read())

    def createChildCertificate(self, childname, extension):
        keyfilename = "%skey.pem" % childname
        csrfilename = "%scsr.pem" % childname
        certfilename = "%scert.pem" % childname
        keyfile = os.path.join(self.workdir_cert_appli, 'private', keyfilename)
        self.SendCommandOpenssl('genrsa -out %s %d' % (keyfile, self.sizeChild))
        csrfile = os.path.join(self.workdir_cert_appli, 'csr', csrfilename)
        self.SendCommandOpenssl('req '
                                '-config %s '
                                '-new '
                                '-sha256 '
                                '-key %s '
                                '-out %s '
                                '-subj /C=%s/ST=%s/L=%s/O=%s/CN=%s' % (self.configappli,
                                                                       keyfile,
                                                                       csrfile,
                                                                       self.countryName,
                                                                       self.stateOrProvinceName,
                                                                       self.localityName,
                                                                       self.organizationName,
                                                                       self.commonName))
        certfile = os.path.join(self.workdir_cert_appli, 'certs', certfilename)
        # Sign certificate
        self.SendCommandOpenssl('ca '
                                '-config %s '
                                '-extensions %s '
                                '-days 390 '
                                '-notext '
                                '-md sha256 '
                                '-passin pass:%s '
                                '-in %s '
                                '-batch '
                                '-out %s ' % (self.configappli,
                                              extension,
                                              self.passappli,
                                              csrfile,
                                              certfile))
        self.SendCommandOpenssl('x509 -noout -text -in %s' % (certfile))
        certcafilename = os.path.join(self.workdir_cert_appli, 'certs', 'cachaincert.pem')
        self.SendCommandOpenssl('verify -CAfile %s %s' % (certcafilename, certfile))


def main(fileLog, logLevel, show_log_console,
         workdir_cert_ca, workdir_cert_appli, openssl,
         sizeCa, sizeAppli, sizeChild,
         passca, passappli,
         countryName, stateOrProvinceName, localityName, organizationName, commonName):
    """ Main function """
    # Manage log
    logging.getLogger('logging')
    numeric_level = getattr(logging, logLevel.upper(), None)
    if not isinstance(numeric_level, int):
        raise ValueError('Invalid log level: %s' % logLevel)
    handlers=[]
    if show_log_console:
        handlers.append(logging.StreamHandler())
    if fileLog:
        handlers.append(logging.FileHandler(fileLog.name))
    logging.basicConfig(handlers=handlers, level=numeric_level,
        format='%(asctime)s %(levelname)s [pid:%(process)d] [%(funcName)s:%(lineno)d] %(message)s')

    certicate = Certificate(openssl, workdir_cert_ca, workdir_cert_appli,
                            passca, passappli,
                            countryName,
                            stateOrProvinceName,
                            localityName,
                            organizationName,
                             commonName,
                             sizeCa,
                             sizeAppli ,
                             sizeChild)
    logging.info("Generate CA certificate")
    certicate.createCACertificate()
    logging.info("Generate Application certificate")
    certicate.createApplicationCertificate()
    logging.info("Generate Server certificate")
    certicate.createChildCertificate('server', 'server_cert')
    logging.info("Generate Client certificate")
    certicate.createChildCertificate('client', 'client_cert')
    logging.info("Certifcate generated")


if __name__ == '__main__':
    parser = argparse.ArgumentParser(description='Create certificate')
    parser.add_argument('--version', action='version', version='%(prog)s 1.0')
    parser.add_argument( '--openssl', default='openssl', help='binary openssl')
    parser.add_argument('-c', '--workdir-cert-ca', default='ca', help='workdir certificate CA')
    parser.add_argument('-a', '--workdir-cert-appli', default='ca/appli', help='workdir certificate Application')
    parser.add_argument( '--show-log-console', action='store_true',
        help='show message in console', default=False)
    parser.add_argument('--filelog', type=argparse.FileType('wt'),
        default=None, help='log file')
    parser.add_argument('--log',
        default='INFO', help='log level [DEBUG, INFO, WARNING, ERROR')
    parser.add_argument('--sizeCa', type=int, default=4096, help='Define size key for CA certificate')
    parser.add_argument('--sizeAppli', type=int, default=4096, help='Define size key for Application certificate')
    parser.add_argument('--sizeChild', type=int, default=4096, help='Define size key for Child certificate')
    parser.add_argument('--passca', default='OpenNelCA9439', help='define password for CA certificate')
    parser.add_argument('--passappli', default='OpenNelAPPLI1097', help='define password for Application certificate')
    parser.add_argument('--countryName', default='FR', help='countryName for certicate')
    parser.add_argument('--stateOrProvinceName', default='France', help='stateOrProvinceName for certicate')
    parser.add_argument('--localityName', default='Paris', help='localityName for certicate')
    parser.add_argument('--organizationName', default='khanat', help='organizationName for certicate')
    parser.add_argument('--commonName', default='khanat', help='commonName for certicate')
    args = parser.parse_args()
    main(fileLog = args.filelog,
         logLevel = args.log,
         show_log_console = args.show_log_console,
         workdir_cert_ca = args.workdir_cert_ca,
         workdir_cert_appli = args.workdir_cert_appli,
         openssl = args.openssl,
         sizeCa = args.sizeCa,
         sizeAppli = args.sizeAppli,
         sizeChild = args.sizeChild,
         passca = args.passca,
         passappli = args.passappli,
         countryName = args.countryName,
         stateOrProvinceName = args.stateOrProvinceName,
         localityName = args.localityName,
         organizationName = args.organizationName,
         commonName = args.commonName)