lemur/lemur/certificates/service.py

"""
.. module: service
    :platform: Unix
    :copyright: (c) 2015 by Netflix Inc., see AUTHORS for more
    :license: Apache, see LICENSE for more details.
.. moduleauthor:: Kevin Glisson <kglisson@netflix.com>
"""
import arrow

from sqlalchemy import func, or_
from flask import g, current_app

from lemur import database
from lemur.plugins.base import plugins
from lemur.certificates.models import Certificate

from lemur.destinations.models import Destination
from lemur.notifications.models import Notification
from lemur.authorities.models import Authority
from lemur.domains.models import Domain

from lemur.roles.models import Role

from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes, serialization
from cryptography.hazmat.primitives.asymmetric import rsa


def get(cert_id):
    """
    Retrieves certificate by it's ID.

    :param cert_id:
    :return:
    """
    return database.get(Certificate, cert_id)


def get_by_name(name):
    """
    Retrieves certificate by it's Name.

    :param name:
    :return:
    """
    return database.get(Certificate, name, field='name')


def delete(cert_id):
    """
    Delete's a certificate.

    :param cert_id:
    """
    database.delete(get(cert_id))


def get_all_certs():
    """
    Retrieves all certificates within Lemur.

    :return:
    """
    return Certificate.query.all()


def find_duplicates(cert_body):
    """
    Finds certificates that already exist within Lemur. We do this by looking for
    certificate bodies that are the same. This is the most reliable way to determine
    if a certificate is already being tracked by Lemur.

    :param cert_body:
    :return:
    """
    return Certificate.query.filter_by(body=cert_body).all()


def export(cert, export_plugin):
    """
    Exports a certificate to the requested format. This format
    may be a binary format.

    :param export_plugin:
    :param cert:
    :return:
    """
    plugin = plugins.get(export_plugin['slug'])

    return plugin.export(cert.body, cert.chain, cert.private_key, export_plugin['pluginOptions'])


def update(cert_id, owner, description, active, destinations, notifications, replaces):
    """
    Updates a certificate
    :param cert_id:
    :param owner:
    :param description:
    :param active:
    :param destinations:
    :param notifications:
    :param replaces:
    :return:
    """
    from lemur.notifications import service as notification_service
    cert = get(cert_id)
    cert.active = active
    cert.description = description

    # we might have to create new notifications if the owner changes
    new_notifications = []
    # get existing names to remove
    notification_name = "DEFAULT_{0}".format(cert.owner.split('@')[0].upper())
    for n in notifications:
        if notification_name not in n.label:
            new_notifications.append(n)

    notification_name = "DEFAULT_{0}".format(owner.split('@')[0].upper())
    new_notifications += notification_service.create_default_expiration_notifications(notification_name, owner)

    cert.notifications = new_notifications

    database.update_list(cert, 'destinations', Destination, destinations)
    database.update_list(cert, 'replaces', Certificate, replaces)

    cert.owner = owner

    return database.update(cert)


def mint(issuer_options):
    """
    Minting is slightly different for each authority.
    Support for multiple authorities is handled by individual plugins.

    :param issuer_options:
    """
    authority = issuer_options['authority']

    issuer = plugins.get(authority.plugin_name)

    csr, private_key = create_csr(issuer_options)

    issuer_options['creator'] = g.user.email
    cert_body, cert_chain = issuer.create_certificate(csr, issuer_options)

    cert = Certificate(cert_body, private_key, cert_chain)

    cert.user = g.user
    cert.authority = authority
    database.update(cert)
    return cert, private_key, cert_chain,


def import_certificate(**kwargs):
    """
    Uploads already minted certificates and pulls the required information into Lemur.

    This is to be used for certificates that are created outside of Lemur but
    should still be tracked.

    Internally this is used to bootstrap Lemur with external
    certificates, and used when certificates are 'discovered' through various discovery
    techniques. was still in aws.

    :param kwargs:
    """
    from lemur.users import service as user_service
    from lemur.notifications import service as notification_service
    cert = Certificate(kwargs['public_certificate'], chain=kwargs['intermediate_certificate'])

    # TODO future source plugins might have a better understanding of who the 'owner' is we should support this
    cert.owner = kwargs.get('owner', current_app.config.get('LEMUR_SECURITY_TEAM_EMAIL')[0])
    cert.creator = kwargs.get('creator', user_service.get_by_email('lemur@nobody'))

    # NOTE existing certs may not follow our naming standard we will
    # overwrite the generated name with the actual cert name
    if kwargs.get('name'):
        cert.name = kwargs.get('name')

    if kwargs.get('user'):
        cert.user = kwargs.get('user')

    notification_name = 'DEFAULT_SECURITY'
    notifications = notification_service.create_default_expiration_notifications(notification_name, current_app.config.get('LEMUR_SECURITY_TEAM_EMAIL'))
    database.update_list(cert, 'replaces', Certificate, kwargs['replacements'])
    cert.notifications = notifications

    cert = database.create(cert)
    return cert


def upload(**kwargs):
    """
    Allows for pre-made certificates to be imported into Lemur.
    """
    from lemur.notifications import service as notification_service
    cert = Certificate(
        kwargs.get('public_cert'),
        kwargs.get('private_key'),
        kwargs.get('intermediate_cert'),
    )

    # we override the generated name if one is provided
    if kwargs.get('name'):
        cert.name = kwargs['name']

    cert.description = kwargs.get('description')

    cert.owner = kwargs['owner']
    cert = database.create(cert)

    g.user.certificates.append(cert)

    database.update_list(cert, 'destinations', Destination, kwargs.get('destinations'))
    database.update_list(cert, 'notifications', Notification, kwargs.get('notifications'))
    database.update_list(cert, 'replaces', Certificate, kwargs['replacements'])

    # create default notifications for this certificate if none are provided
    notifications = []
    if not kwargs.get('notifications'):
        notification_name = "DEFAULT_{0}".format(cert.owner.split('@')[0].upper())
        notifications += notification_service.create_default_expiration_notifications(notification_name, [cert.owner])

    notification_name = 'DEFAULT_SECURITY'
    notifications += notification_service.create_default_expiration_notifications(notification_name, current_app.config.get('LEMUR_SECURITY_TEAM_EMAIL'))
    cert.notifications = notifications

    database.update(cert)
    return cert


def create(**kwargs):
    """
    Creates a new certificate.
    """
    from lemur.notifications import service as notification_service
    cert, private_key, cert_chain = mint(kwargs)

    cert.owner = kwargs['owner']

    database.create(cert)
    cert.description = kwargs['description']
    g.user.certificates.append(cert)
    database.update(g.user)

    # do this after the certificate has already been created because if it fails to upload to the third party
    # we do not want to lose the certificate information.
    database.update_list(cert, 'destinations', Destination, kwargs.get('destinations'))
    database.update_list(cert, 'replaces', Certificate, kwargs['replacements'])
    database.update_list(cert, 'notifications', Notification, kwargs.get('notifications'))

    # create default notifications for this certificate if none are provided
    notifications = cert.notifications
    if not kwargs.get('notifications'):
        notification_name = "DEFAULT_{0}".format(cert.owner.split('@')[0].upper())
        notifications += notification_service.create_default_expiration_notifications(notification_name, [cert.owner])

    notification_name = 'DEFAULT_SECURITY'
    notifications += notification_service.create_default_expiration_notifications(notification_name,
                                                                                  current_app.config.get('LEMUR_SECURITY_TEAM_EMAIL'))
    cert.notifications = notifications

    database.update(cert)
    return cert


def render(args):
    """
    Helper function that allows use to render our REST Api.

    :param args:
    :return:
    """
    query = database.session_query(Certificate)

    time_range = args.pop('time_range')
    destination_id = args.pop('destination_id')
    notification_id = args.pop('notification_id', None)
    show = args.pop('show')
    # owner = args.pop('owner')
    # creator = args.pop('creator')  # TODO we should enabling filtering by owner

    filt = args.pop('filter')

    if filt:
        terms = filt.split(';')

        if 'issuer' in terms:
            # we can't rely on issuer being correct in the cert directly so we combine queries
            sub_query = database.session_query(Authority.id)\
                .filter(Authority.name.ilike('%{0}%'.format(terms[1])))\
                .subquery()

            query = query.filter(
                or_(
                    Certificate.issuer.ilike('%{0}%'.format(terms[1])),
                    Certificate.authority_id.in_(sub_query)
                )
            )
            return database.sort_and_page(query, Certificate, args)

        elif 'destination' in terms:
            query = query.filter(Certificate.destinations.any(Destination.id == terms[1]))
        elif 'active' in filt:  # this is really weird but strcmp seems to not work here??
            query = query.filter(Certificate.active == terms[1])
        elif 'cn' in terms:
            query = query.filter(
                or_(
                    Certificate.cn.ilike('%{0}%'.format(terms[1])),
                    Certificate.domains.any(Domain.name.ilike('%{0}%'.format(terms[1])))
                )
            )
        else:
            query = database.filter(query, Certificate, terms)

    if show:
        sub_query = database.session_query(Role.name).filter(Role.user_id == g.user.id).subquery()
        query = query.filter(
            or_(
                Certificate.user_id == g.user.id,
                Certificate.owner.in_(sub_query)
            )
        )

    if destination_id:
        query = query.filter(Certificate.destinations.any(Destination.id == destination_id))

    if notification_id:
        query = query.filter(Certificate.notifications.any(Notification.id == notification_id))

    if time_range:
        to = arrow.now().replace(weeks=+time_range).format('YYYY-MM-DD')
        now = arrow.now().format('YYYY-MM-DD')
        query = query.filter(Certificate.not_after <= to).filter(Certificate.not_after >= now)

    return database.sort_and_page(query, Certificate, args)


def create_csr(csr_config):
    """
    Given a list of domains create the appropriate csr
    for those domains

    :param csr_config:
    """
    private_key = rsa.generate_private_key(
        public_exponent=65537,
        key_size=2048,
        backend=default_backend()
    )

    # TODO When we figure out a better way to validate these options they should be parsed as str
    builder = x509.CertificateSigningRequestBuilder()
    builder = builder.subject_name(x509.Name([
        x509.NameAttribute(x509.OID_COMMON_NAME, csr_config['commonName']),
        x509.NameAttribute(x509.OID_ORGANIZATION_NAME, csr_config['organization']),
        x509.NameAttribute(x509.OID_ORGANIZATIONAL_UNIT_NAME, csr_config['organizationalUnit']),
        x509.NameAttribute(x509.OID_COUNTRY_NAME, csr_config['country']),
        x509.NameAttribute(x509.OID_STATE_OR_PROVINCE_NAME, csr_config['state']),
        x509.NameAttribute(x509.OID_LOCALITY_NAME, csr_config['location']),
    ]))

    builder = builder.add_extension(
        x509.BasicConstraints(ca=False, path_length=None), critical=True,
    )

    if csr_config.get('extensions'):
        for k, v in csr_config.get('extensions', {}).items():
            if k == 'subAltNames':
                # map types to their x509 objects
                general_names = []
                for name in v['names']:
                    if name['nameType'] == 'DNSName':
                        general_names.append(x509.DNSName(name['value']))

                builder = builder.add_extension(
                    x509.SubjectAlternativeName(general_names), critical=True
                )

    # TODO support more CSR options, none of the authority plugins currently support these options
    #    builder.add_extension(
    #        x509.KeyUsage(
    #            digital_signature=digital_signature,
    #            content_commitment=content_commitment,
    #            key_encipherment=key_enipherment,
    #            data_encipherment=data_encipherment,
    #            key_agreement=key_agreement,
    #            key_cert_sign=key_cert_sign,
    #            crl_sign=crl_sign,
    #            encipher_only=enchipher_only,
    #            decipher_only=decipher_only
    #        ), critical=True
    #    )
    #
    #    # we must maintain our own list of OIDs here
    #    builder.add_extension(
    #        x509.ExtendedKeyUsage(
    #            server_authentication=server_authentication,
    #            email=
    #        )
    #    )
    #
    #    builder.add_extension(
    #        x509.AuthorityInformationAccess()
    #    )
    #
    #    builder.add_extension(
    #        x509.AuthorityKeyIdentifier()
    #    )
    #
    #    builder.add_extension(
    #        x509.SubjectKeyIdentifier()
    #    )
    #
    #    builder.add_extension(
    #        x509.CRLDistributionPoints()
    #    )
    #
    #    builder.add_extension(
    #        x509.ObjectIdentifier(oid)
    #    )

    request = builder.sign(
        private_key, hashes.SHA256(), default_backend()
    )

    # serialize our private key and CSR
    pem = private_key.private_bytes(
        encoding=serialization.Encoding.PEM,
        format=serialization.PrivateFormat.TraditionalOpenSSL,  # would like to use PKCS8 but AWS ELBs don't like it
        encryption_algorithm=serialization.NoEncryption()
    )

    csr = request.public_bytes(
        encoding=serialization.Encoding.PEM
    )

    return csr, pem


def stats(**kwargs):
    """
    Helper that defines some useful statistics about certifications.

    :param kwargs:
    :return:
    """
    if kwargs.get('metric') == 'not_after':
        start = arrow.utcnow()
        end = start.replace(weeks=+32)
        items = database.db.session.query(Certificate.issuer, func.count(Certificate.id))\
            .group_by(Certificate.issuer)\
            .filter(Certificate.not_after <= end.format('YYYY-MM-DD')) \
            .filter(Certificate.not_after >= start.format('YYYY-MM-DD')).all()

    else:
        attr = getattr(Certificate, kwargs.get('metric'))
        query = database.db.session.query(attr, func.count(attr))

        items = query.group_by(attr).all()

    keys = []
    values = []
    for key, count in items:
        keys.append(key)
        values.append(count)

    return {'labels': keys, 'values': values}