# This file is part of django-ca (https://github.com/mathiasertl/django-ca).
#
# django-ca 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.
#
# django-ca 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 django-ca. If not,
# see <http://www.gnu.org/licenses/>.
import pathlib
from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import serialization
from cryptography.hazmat.primitives.serialization import Encoding
from cryptography.hazmat.primitives.serialization import PrivateFormat
from cryptography.x509.oid import AuthorityInformationAccessOID
from django.core.files.base import ContentFile
from django.db import models
from django.urls import reverse
from django.utils.encoding import force_bytes
from django.utils.encoding import force_str
from . import ca_settings
from .extensions import Extension
from .extensions import IssuerAlternativeName
from .extensions import NameConstraints
from .profiles import Profile
from .profiles import profiles
from .signals import post_create_ca
from .signals import post_issue_cert
from .signals import pre_create_ca
from .subject import Subject
from .utils import ca_storage
from .utils import generate_private_key
from .utils import get_cert_builder
from .utils import int_to_hex
from .utils import parse_hash_algorithm
from .utils import validate_hostname
from .utils import validate_key_parameters
class CertificateManagerMixin(object):
def get_common_extensions(self, issuer_url=None, crl_url=None, ocsp_url=None):
extensions = []
if crl_url:
urls = [x509.UniformResourceIdentifier(force_str(c)) for c in crl_url]
dps = [x509.DistributionPoint(full_name=[c], relative_name=None, crl_issuer=None, reasons=None)
for c in urls]
extensions.append((False, x509.CRLDistributionPoints(dps)))
auth_info_access = []
if ocsp_url:
uri = x509.UniformResourceIdentifier(force_str(ocsp_url))
auth_info_access.append(x509.AccessDescription(
access_method=AuthorityInformationAccessOID.OCSP, access_location=uri))
if issuer_url:
uri = x509.UniformResourceIdentifier(force_str(issuer_url))
auth_info_access.append(x509.AccessDescription(
access_method=AuthorityInformationAccessOID.CA_ISSUERS, access_location=uri))
if auth_info_access:
extensions.append((False, x509.AuthorityInformationAccess(auth_info_access)))
return extensions
def _extra_extensions(self, builder, extra_extensions):
for ext in extra_extensions:
if isinstance(ext, x509.extensions.Extension):
builder = builder.add_extension(ext.value, critical=ext.critical)
elif isinstance(ext, Extension):
builder = builder.add_extension(**ext.for_builder())
else:
raise ValueError('Cannot add extension of type %s' % type(ext).__name__)
return builder
class CertificateAuthorityManager(CertificateManagerMixin, models.Manager):
[docs] def init(self, name, subject, expires=None, algorithm=None, parent=None, default_hostname=None,
pathlen=None, issuer_url=None, issuer_alt_name='', crl_url=None, ocsp_url=None,
ca_issuer_url=None, ca_crl_url=None, ca_ocsp_url=None, name_constraints=None,
password=None, parent_password=None, ecc_curve=None, key_type='RSA', key_size=None,
extra_extensions=None, path='ca'):
"""Create a new certificate authority.
Parameters
----------
name : str
The name of the CA. This is a human-readable string and is used for administrative purposes only.
subject : dict or str or :py:class:`~django_ca.subject.Subject`
Subject string, e.g. ``"/CN=example.com"`` or ``Subject("/CN=example.com")``. The value is
actually passed to :py:class:`~django_ca.subject.Subject` if it is not already an instance of that
class.
expires : datetime, optional
Datetime for when this certificate authority will expire, defaults to
:ref:`CA_DEFAULT_EXPIRES <settings-ca-default-expires>`.
algorithm : str or :py:class:`~cg:cryptography.hazmat.primitives.hashes.HashAlgorithm`, optional
Hash algorithm used when signing the certificate, passed to
:py:func:`~django_ca.utils.parse_hash_algorithm`. The default is the value of the
:ref:`CA_DIGEST_ALGORITHM <settings-ca-digest-algorithm>` setting.
parent : :py:class:`~django_ca.models.CertificateAuthority`, optional
Parent certificate authority for the new CA. Passing this value makes the CA an intermediate
authority.
default_hostname : str, optional
Override the url configured with :ref:`CA_DEFAULT_HOSTNAME <settings-ca-default-hostname>` with a
different hostname. Set to ``False`` to disable the hostname.
pathlen : int, optional
Value of the path length attribute for the :py:class:`~django_ca.extensions.BasicConstraints`
extension.
issuer_url : str
URL for the DER/ASN1 formatted certificate that is signing certificates.
issuer_alt_name : :py:class:`~django_ca.extensions.IssuerAlternativeName` or str, optional
IssuerAlternativeName used when signing certificates. If the value is not an instance of
:py:class:`~django_ca.extensions.IssuerAlternativeName`, it will be passed as argument to
the constructor of the class.
crl_url : list of str, optional
CRL URLs used for certificates signed by this CA.
ocsp_url : str, optional
OCSP URL used for certificates signed by this CA. The default is no value, unless
:ref:`CA_DEFAULT_HOSTNAME <settings-ca-default-hostname>` is set.
ca_issuer_url : str, optional
URL for the DER/ASN1 formatted certificate that is signing this CA. For intermediate CAs, this
would usually be the ``issuer_url`` of the parent CA.
ca_crl_url : list of str, optional
CRL URLs used for this CA. This value is only meaningful for intermediate CAs.
ca_ocsp_url : str, optional
OCSP URL used for this CA. This value is only meaningful for intermediate CAs. The default is
no value, unless :ref:`CA_DEFAULT_HOSTNAME <settings-ca-default-hostname>` is set.
name_constraints : list of lists or :py:class:`~django_ca.extensions.NameConstraints`
List of names that this CA can sign and/or cannot sign. The value is passed to
:py:class:`~django_ca.extensions.NameConstraints` if the value is not already an instance of that
class.
password : bytes, optional
Password to encrypt the private key with.
parent_password : bytes, optional
Password that the private key of the parent CA is encrypted with.
ecc_curve : str or EllipticCurve, optional
The elliptic curve to use for ECC type keys, passed verbatim to
:py:func:`~django_ca.utils.parse_key_curve`.
key_type: str, optional
The type of private key to generate, must be one of ``"RSA"``, ``"DSA"`` or ``"ECC"``, with
``"RSA"`` being the default.
key_size : int, optional
Integer specifying the key size, must be a power of two (e.g. 2048, 4096, ...). Defaults to
the :ref:`CA_DEFAULT_KEY_SIZE <settings-ca-default-key-size>`, unused if ``key_type="ECC"``.
extra_extensions : list of :py:class:`cg:cryptography.x509.Extension` or \
:py:class:`django_ca.extensions.Extension`, optional
An optional list of additional extensions to add to the certificate.
path : str or pathlib.PurePath, optional
Where to store the CA private key (default ``ca``).
Raises
------
ValueError
For various cases of wrong input data (e.g. ``key_size`` not being the power of two).
PermissionError
If the private key file cannot be written to disk.
"""
# NOTE: Already verified by KeySizeAction, so these checks are only for when the Python API is used
# directly.
key_size, key_type, ecc_curve = validate_key_parameters(key_size, key_type, ecc_curve)
algorithm = parse_hash_algorithm(algorithm)
# Normalize extensions to django_ca.extensions.Extension subclasses
if not isinstance(subject, Subject):
subject = Subject(subject)
if issuer_alt_name and not isinstance(issuer_alt_name, IssuerAlternativeName):
issuer_alt_name = IssuerAlternativeName(issuer_alt_name)
issuer_alt_name = ','.join(issuer_alt_name.serialize()['value'])
if crl_url is None:
crl_url = []
serial = x509.random_serial_number()
hex_serial = int_to_hex(serial)
if default_hostname is None:
default_hostname = ca_settings.CA_DEFAULT_HOSTNAME
# If there is a default hostname, use it to compute some URLs from that
if default_hostname:
default_hostname = validate_hostname(default_hostname, allow_port=True)
if parent:
root_serial = parent.root.serial
else:
root_serial = hex_serial
# Set OCSP urls
if not ocsp_url:
ocsp_path = reverse('django_ca:ocsp-cert-post', kwargs={'serial': hex_serial})
ocsp_url = 'http://%s%s' % (default_hostname, ocsp_path)
if parent and not ca_ocsp_url: # OCSP for CA only makes sense in intermediate CAs
ocsp_path = reverse('django_ca:ocsp-ca-post', kwargs={'serial': hex_serial})
ca_ocsp_url = 'http://%s%s' % (default_hostname, ocsp_path)
# Set issuer path
issuer_path = reverse('django_ca:issuer', kwargs={'serial': root_serial})
if parent and not ca_issuer_url:
ca_issuer_url = 'http://%s%s' % (default_hostname, issuer_path)
if not issuer_url:
issuer_url = 'http://%s%s' % (default_hostname, issuer_path)
# Set CRL URLs
if not crl_url:
crl_path = reverse('django_ca:crl', kwargs={'serial': hex_serial})
crl_url = ['http://%s%s' % (default_hostname, crl_path)]
if parent and not ca_crl_url: # CRL for CA only makes sense in intermediate CAs
ca_crl_path = reverse('django_ca:ca-crl', kwargs={'serial': hex_serial})
ca_crl_url = ['http://%s%s' % (default_hostname, ca_crl_path)]
pre_create_ca.send(
sender=self.model, name=name, key_size=key_size, key_type=key_type, algorithm=algorithm,
expires=expires, parent=parent, subject=subject, pathlen=pathlen, issuer_url=issuer_url,
issuer_alt_name=issuer_alt_name, crl_url=crl_url, ocsp_url=ocsp_url, ca_issuer_url=ca_issuer_url,
ca_crl_url=ca_crl_url, ca_ocsp_url=ca_ocsp_url, name_constraints=name_constraints,
password=password, parent_password=parent_password, extra_extensions=extra_extensions)
private_key = generate_private_key(key_size, key_type, ecc_curve)
public_key = private_key.public_key()
builder = get_cert_builder(expires, serial=serial)
builder = builder.public_key(public_key)
subject = subject.name
builder = builder.subject_name(subject)
builder = builder.add_extension(x509.BasicConstraints(ca=True, path_length=pathlen), critical=True)
builder = builder.add_extension(x509.KeyUsage(
key_cert_sign=True, crl_sign=True, digital_signature=False, content_commitment=False,
key_encipherment=False, data_encipherment=False, key_agreement=False, encipher_only=False,
decipher_only=False), critical=True)
subject_key_id = x509.SubjectKeyIdentifier.from_public_key(public_key)
builder = builder.add_extension(subject_key_id, critical=False)
if parent is None:
builder = builder.issuer_name(subject)
private_sign_key = private_key
aki = x509.AuthorityKeyIdentifier.from_issuer_public_key(public_key)
else:
builder = builder.issuer_name(parent.x509.subject)
private_sign_key = parent.key(parent_password)
aki = parent.get_authority_key_identifier()
builder = builder.add_extension(aki, critical=False)
for critical, ext in self.get_common_extensions(ca_issuer_url, ca_crl_url, ca_ocsp_url):
builder = builder.add_extension(ext, critical=critical)
if name_constraints:
if not isinstance(name_constraints, NameConstraints):
name_constraints = NameConstraints(name_constraints)
builder = builder.add_extension(**name_constraints.for_builder())
if extra_extensions:
builder = self._extra_extensions(builder, extra_extensions)
certificate = builder.sign(private_key=private_sign_key, algorithm=algorithm,
backend=default_backend())
# Normalize extensions for create()
crl_url = '\n'.join(crl_url)
ca = self.model(name=name, issuer_url=issuer_url, issuer_alt_name=issuer_alt_name,
ocsp_url=ocsp_url, crl_url=crl_url, parent=parent)
ca.x509 = certificate
if password is None:
encryption = serialization.NoEncryption()
else:
encryption = serialization.BestAvailableEncryption(password)
pem = private_key.private_bytes(encoding=Encoding.PEM, format=PrivateFormat.PKCS8,
encryption_algorithm=encryption)
# write private key to file
path = path / pathlib.PurePath('%s.key' % ca.serial.replace(':', ''))
ca.private_key_path = ca_storage.save(str(path), ContentFile(pem))
ca.save()
post_create_ca.send(sender=self.model, ca=ca)
return ca
[docs]class CertificateManager(CertificateManagerMixin, models.Manager):
def parse_csr(self, csr, csr_format):
if isinstance(csr, x509.CertificateSigningRequest):
return csr
elif csr_format == Encoding.PEM:
return x509.load_pem_x509_csr(force_bytes(csr), default_backend())
elif csr_format == Encoding.DER:
return x509.load_der_x509_csr(force_bytes(csr), default_backend())
raise ValueError('Unknown CSR format passed: %s' % csr_format)
[docs] def create_cert(self, ca, csr, csr_format=Encoding.PEM, profile=None, autogenerated=None, **kwargs):
"""Create and sign a new certificate based on the given profile.
Parameters
----------
ca : :py:class:`~django_ca.models.CertificateAuthority`
The certificate authority to sign the certificate with.
csr : str or :py:class:`~cg:cryptography.x509.CertificateSigningRequest`
A valid CSR. If not already a :py:class:`~cg:cryptography.x509.CertificateSigningRequest`, the
format is given by the ``csr_format`` parameter.
csr_format : :py:class:`~cg:cryptography.hazmat.primitives.serialization.Encoding`, optional
The format of the CSR. The default is ``PEM``.
profile : str or :py:class:`~django_ca.profiles.Profile`, optional
The name of a profile or a manually created :py:class:`~django_ca.profiles.Profile` instance. If
not given, the profile configured by :ref:`CA_DEFAULT_PROFILE <settings-ca-default-profile>` is
used.
autogenerated : bool, optional
Override the profiles ``autogenerated`` flag.
**kwargs
All other keyword arguments are passed to :py:func:`Profiles.create_cert()
<django_ca.profiles.Profile.create_cert>`.
"""
if not isinstance(profile, Profile):
profile = profiles[profile]
csr = self.parse_csr(csr, csr_format=csr_format)
cert = profile.create_cert(ca, csr, **kwargs)
c = self.model(ca=ca, csr=csr.public_bytes(Encoding.PEM).decode('utf-8'), profile=profile.name)
c.x509 = cert
if autogenerated is None:
c.autogenerated = profile.autogenerated
else:
c.autogenerated = autogenerated
c.save()
post_issue_cert.send(sender=self.model, cert=c)
return c