dollyx509

#!/usr/bin/env python
"""
dollyx509

Clone X.509 certificates by reading a certificate and generating new key material.

Author: Emanuel Duss
"""

import argparse
import OpenSSL.crypto

def parse_args():
    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawTextHelpFormatter)

    parser.add_argument('-i', '--certin',metavar='inputcert', required=True,
        dest='inputcert', help='Certificate to clone')
    parser.add_argument('-c', '--certout',metavar='outputcert', required=True,
        dest='outputcert', help='Output file of cloned certificate')
    parser.add_argument('-k', '--keyout',metavar='outputkey', required=True,
        dest='outputkey', help='Output file of generated private key')
    parser.add_argument('--inform', choices={'pem', 'der'}, default='pem',
        dest='inputformat', help='Input format of certificate')
    parser.add_argument('--outform', choices={'pem', 'der'}, default='pem',
        dest='outputformat', help='Output format of certificate/key')

    return parser.parse_args()

class Certificate:
    def __init__(self, file, format='pem'):
        self.import_certificate(file, format)

    def __get_filetype(self, format):
        if format == 'der':
            return OpenSSL.crypto.FILETYPE_ASN1
        else:
            return OpenSSL.crypto.FILETYPE_PEM

    def import_certificate(self, file, format='pem'):
        with open(file, "r") as f:
            self.cert = OpenSSL.crypto.load_certificate(self.__get_filetype(format), f.read())

    def clone(self):
        self.key = OpenSSL.crypto.PKey()
        self.key.generate_key(self.cert.get_pubkey().type(), self.cert.get_pubkey().bits())
        self.cert.set_pubkey(self.key)
        self.cert.sign(self.key,'sha256')

    def export_certificate(self, file, format='pem'):
        with open(file, "wb") as f:
            f.write(OpenSSL.crypto.dump_certificate(self.__get_filetype(format), self.cert))

    def export_privatekey(self, file, format='pem'):
        with open(file, "wb") as f:
            f.write(OpenSSL.crypto.dump_privatekey(self.__get_filetype(format), self.key))

def main():
    args = parse_args()

    certificate = Certificate(args.inputcert, args.inputformat)
    certificate.clone()
    certificate.export_certificate(args.outputcert, args.outputformat)
    certificate.export_privatekey(args.outputkey, args.outputformat)

if __name__ == '__main__':
    main()