branch: master
certs.py
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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#***************************************************************************
# _ _ ____ _
# Project ___| | | | _ \| |
# / __| | | | |_) | |
# | (__| |_| | _ <| |___
# \___|\___/|_| \_\_____|
#
# Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at https://curl.se/docs/copyright.html.
#
# You may opt to use, copy, modify, merge, publish, distribute and/or sell
# copies of the Software, and permit persons to whom the Software is
# furnished to do so, under the terms of the COPYING file.
#
# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
# KIND, either express or implied.
#
# SPDX-License-Identifier: curl
#
###########################################################################
#
import base64
import ipaddress
import os
import re
import shutil
import subprocess
from datetime import timedelta, datetime, timezone
from typing import List, Any, Optional
from cryptography import x509
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives._serialization import PublicFormat
from cryptography.hazmat.primitives.asymmetric import ec, rsa
from cryptography.hazmat.primitives.asymmetric.ec import EllipticCurvePrivateKey
from cryptography.hazmat.primitives.asymmetric.rsa import RSAPrivateKey
from cryptography.hazmat.primitives.serialization import Encoding, PrivateFormat, NoEncryption, load_pem_private_key
from cryptography.x509 import ExtendedKeyUsageOID, NameOID
EC_SUPPORTED = {}
EC_SUPPORTED.update([(curve.name.upper(), curve) for curve in [
ec.SECP192R1,
ec.SECP224R1,
ec.SECP256R1,
ec.SECP384R1,
]])
def _private_key(key_type):
if isinstance(key_type, str):
key_type = key_type.upper()
m = re.match(r'^(RSA)?(\d+)$', key_type)
if m:
key_type = int(m.group(2))
if isinstance(key_type, int):
return rsa.generate_private_key(
public_exponent=65537,
key_size=key_type,
backend=default_backend()
)
if not isinstance(key_type, ec.EllipticCurve) and key_type in EC_SUPPORTED:
key_type = EC_SUPPORTED[key_type]
return ec.generate_private_key(
curve=key_type,
backend=default_backend()
)
class CertificateSpec:
def __init__(self, name: Optional[str] = None,
domains: Optional[List[str]] = None,
email: Optional[str] = None,
key_type: Optional[str] = None,
single_file: bool = False,
valid_from: timedelta = timedelta(days=-1),
valid_to: timedelta = timedelta(days=89),
client: bool = False,
check_valid: bool = True,
sub_specs: Optional[List['CertificateSpec']] = None):
self._name = name
self.domains = domains
self.client = client
self.email = email
self.key_type = key_type
self.single_file = single_file
self.valid_from = valid_from
self.valid_to = valid_to
self.sub_specs = sub_specs
self.check_valid = check_valid
@property
def name(self) -> Optional[str]:
if self._name:
return self._name
elif self.domains:
return self.domains[0]
return None
@property
def type(self) -> Optional[str]:
if self.domains and len(self.domains):
return "server"
elif self.client:
return "client"
elif self.name:
return "ca"
return None
class Credentials:
def __init__(self,
name: str,
cert: Any,
pkey: Any,
issuer: Optional['Credentials'] = None):
self._name = name
self._cert = cert
self._pkey = pkey
self._issuer = issuer
self._cert_file = None
self._pkey_file = None
self._store = None
self._combined_file = None
@property
def name(self) -> str:
return self._name
@property
def subject(self) -> x509.Name:
return self._cert.subject
@property
def key_type(self):
if isinstance(self._pkey, RSAPrivateKey):
return f"rsa{self._pkey.key_size}"
elif isinstance(self._pkey, EllipticCurvePrivateKey):
return f"{self._pkey.curve.name}"
else:
raise Exception(f"unknown key type: {self._pkey}")
@property
def private_key(self) -> Any:
return self._pkey
def pub_sha256_b64(self) -> Any:
pubkey = self._pkey.public_key()
sha256 = hashes.Hash(algorithm=hashes.SHA256())
sha256.update(pubkey.public_bytes(
encoding=Encoding.DER,
format=PublicFormat.SubjectPublicKeyInfo
))
return base64.b64encode(sha256.finalize()).decode('utf8')
@property
def certificate(self) -> Any:
return self._cert
@property
def cert_pem(self) -> bytes:
return self._cert.public_bytes(Encoding.PEM)
@property
def pkey_pem(self) -> bytes:
return self._pkey.private_bytes(
Encoding.PEM,
PrivateFormat.TraditionalOpenSSL if self.key_type.startswith('rsa') else PrivateFormat.PKCS8,
NoEncryption())
@property
def issuer(self) -> Optional['Credentials']:
return self._issuer
def set_store(self, store: 'CertStore'):
self._store = store
def set_files(self, cert_file: str, pkey_file: Optional[str] = None,
combined_file: Optional[str] = None):
self._cert_file = cert_file
self._pkey_file = pkey_file
self._combined_file = combined_file
@property
def cert_file(self) -> str:
return self._cert_file
@property
def pkey_file(self) -> Optional[str]:
return self._pkey_file
@property
def combined_file(self) -> Optional[str]:
return self._combined_file
@property
def hashdir(self) -> Optional[str]:
return os.path.join(self._store.path, 'hashdir')
def get_first(self, name) -> Optional['Credentials']:
creds = self._store.get_credentials_for_name(name) if self._store else []
return creds[0] if len(creds) else None
def get_credentials_for_name(self, name) -> List['Credentials']:
return self._store.get_credentials_for_name(name) if self._store else []
def issue_certs(self, specs: List[CertificateSpec],
chain: Optional[List['Credentials']] = None) -> List['Credentials']:
return [self.issue_cert(spec=spec, chain=chain) for spec in specs]
def issue_cert(self, spec: CertificateSpec,
chain: Optional[List['Credentials']] = None) -> 'Credentials':
key_type = spec.key_type if spec.key_type else self.key_type
creds = None
if self._store:
creds = self._store.load_credentials(
name=spec.name, key_type=key_type, single_file=spec.single_file,
issuer=self, check_valid=spec.check_valid)
if creds is None:
creds = TestCA.create_credentials(spec=spec, issuer=self, key_type=key_type,
valid_from=spec.valid_from, valid_to=spec.valid_to)
if self._store:
self._store.save(creds, single_file=spec.single_file)
if spec.type == "ca":
self._store.save_chain(creds, "ca", with_root=True)
if spec.sub_specs:
if self._store:
sub_store = CertStore(fpath=os.path.join(self._store.path, creds.name))
creds.set_store(sub_store)
subchain = chain.copy() if chain else []
subchain.append(self)
creds.issue_certs(spec.sub_specs, chain=subchain)
return creds
def create_hashdir(self, openssl):
os.makedirs(self.hashdir, exist_ok=True)
p = subprocess.run(args=[
openssl, 'x509', '-hash', '-noout', '-in', self.cert_file
], capture_output=True, text=True)
if p.returncode != 0:
raise Exception(f'openssl failed to compute cert hash: {p}')
cert_hname = f'{p.stdout.strip()}.0'
shutil.copy(self.cert_file, os.path.join(self.hashdir, cert_hname))
class CertStore:
def __init__(self, fpath: str):
self._store_dir = fpath
if not os.path.exists(self._store_dir):
os.makedirs(self._store_dir)
self._creds_by_name = {}
@property
def path(self) -> str:
return self._store_dir
def save(self, creds: Credentials, name: Optional[str] = None,
chain: Optional[List[Credentials]] = None,
single_file: bool = False) -> None:
name = name if name is not None else creds.name
cert_file = self.get_cert_file(name=name, key_type=creds.key_type)
pkey_file = self.get_pkey_file(name=name, key_type=creds.key_type)
comb_file = self.get_combined_file(name=name, key_type=creds.key_type)
if single_file:
pkey_file = None
with open(cert_file, "wb") as fd:
fd.write(creds.cert_pem)
if chain:
for c in chain:
fd.write(c.cert_pem)
if pkey_file is None:
fd.write(creds.pkey_pem)
if pkey_file is not None:
with open(pkey_file, "wb") as fd:
fd.write(creds.pkey_pem)
with open(comb_file, "wb") as fd:
fd.write(creds.cert_pem)
if chain:
for c in chain:
fd.write(c.cert_pem)
fd.write(creds.pkey_pem)
creds.set_files(cert_file, pkey_file, comb_file)
self._add_credentials(name, creds)
def save_chain(self, creds: Credentials, infix: str, with_root=False):
name = creds.name
chain = [creds]
while creds.issuer is not None:
creds = creds.issuer
chain.append(creds)
if not with_root and len(chain) > 1:
chain = chain[:-1]
chain_file = os.path.join(self._store_dir, f'{name}-{infix}.pem')
with open(chain_file, "wb") as fd:
for c in chain:
fd.write(c.cert_pem)
def _add_credentials(self, name: str, creds: Credentials):
if name not in self._creds_by_name:
self._creds_by_name[name] = []
self._creds_by_name[name].append(creds)
def get_credentials_for_name(self, name) -> List[Credentials]:
return self._creds_by_name[name] if name in self._creds_by_name else []
def get_cert_file(self, name: str, key_type=None) -> str:
key_infix = ".{0}".format(key_type) if key_type is not None else ""
return os.path.join(self._store_dir, f'{name}{key_infix}.cert.pem')
def get_pkey_file(self, name: str, key_type=None) -> str:
key_infix = ".{0}".format(key_type) if key_type is not None else ""
return os.path.join(self._store_dir, f'{name}{key_infix}.pkey.pem')
def get_combined_file(self, name: str, key_type=None) -> str:
return os.path.join(self._store_dir, f'{name}.pem')
def load_pem_cert(self, fpath: str) -> x509.Certificate:
with open(fpath) as fd:
return x509.load_pem_x509_certificate("".join(fd.readlines()).encode())
def load_pem_pkey(self, fpath: str):
with open(fpath) as fd:
return load_pem_private_key("".join(fd.readlines()).encode(), password=None)
def load_credentials(self, name: str, key_type=None,
single_file: bool = False,
issuer: Optional[Credentials] = None,
check_valid: bool = False):
cert_file = self.get_cert_file(name=name, key_type=key_type)
pkey_file = cert_file if single_file else self.get_pkey_file(name=name, key_type=key_type)
comb_file = self.get_combined_file(name=name, key_type=key_type)
if os.path.isfile(cert_file) and os.path.isfile(pkey_file):
cert = self.load_pem_cert(cert_file)
pkey = self.load_pem_pkey(pkey_file)
try:
now = datetime.now(tz=timezone.utc)
if check_valid and \
((cert.not_valid_after_utc < now) or
(cert.not_valid_before_utc > now)):
return None
except AttributeError: # older python
now = datetime.now()
if check_valid and \
((cert.not_valid_after < now) or
(cert.not_valid_before > now)):
return None
creds = Credentials(name=name, cert=cert, pkey=pkey, issuer=issuer)
creds.set_store(self)
creds.set_files(cert_file, pkey_file, comb_file)
self._add_credentials(name, creds)
return creds
return None
class TestCA:
@classmethod
def create_root(cls, name: str, store_dir: str, key_type: str = "rsa2048") -> Credentials:
store = CertStore(fpath=store_dir)
creds = store.load_credentials(name="ca", key_type=key_type, issuer=None)
if creds is None:
creds = TestCA._make_ca_credentials(name=name, key_type=key_type)
store.save(creds, name="ca")
creds.set_store(store)
return creds
@staticmethod
def create_credentials(spec: CertificateSpec, issuer: Credentials, key_type: Any,
valid_from: timedelta = timedelta(days=-1),
valid_to: timedelta = timedelta(days=89),
) -> Credentials:
"""
Create a certificate signed by this CA for the given domains.
:returns: the certificate and private key PEM file paths
"""
if spec.domains and len(spec.domains):
creds = TestCA._make_server_credentials(name=spec.name, domains=spec.domains,
issuer=issuer, valid_from=valid_from,
valid_to=valid_to, key_type=key_type)
elif spec.client:
creds = TestCA._make_client_credentials(name=spec.name, issuer=issuer,
email=spec.email, valid_from=valid_from,
valid_to=valid_to, key_type=key_type)
elif spec.name:
creds = TestCA._make_ca_credentials(name=spec.name, issuer=issuer,
valid_from=valid_from, valid_to=valid_to,
key_type=key_type)
else:
raise Exception(f"unrecognized certificate specification: {spec}")
return creds
@staticmethod
def _make_x509_name(org_name: Optional[str] = None, common_name: Optional[str] = None, parent: x509.Name = None) -> x509.Name:
name_pieces = []
if org_name:
oid = NameOID.ORGANIZATIONAL_UNIT_NAME if parent else NameOID.ORGANIZATION_NAME
name_pieces.append(x509.NameAttribute(oid, org_name))
elif common_name:
name_pieces.append(x509.NameAttribute(NameOID.COMMON_NAME, common_name))
if parent:
name_pieces.extend(list(parent))
return x509.Name(name_pieces)
@staticmethod
def _make_csr(
subject: x509.Name,
pkey: Any,
issuer_subject: Optional[Credentials],
valid_from_delta: Optional[timedelta] = None,
valid_until_delta: Optional[timedelta] = None
) -> x509.CertificateBuilder:
pubkey = pkey.public_key()
issuer_subject = issuer_subject if issuer_subject is not None else subject
valid_from = datetime.now()
if valid_until_delta is not None:
valid_from += valid_from_delta
valid_until = datetime.now()
if valid_until_delta is not None:
valid_until += valid_until_delta
return (
x509.CertificateBuilder()
.subject_name(subject)
.issuer_name(issuer_subject)
.public_key(pubkey)
.not_valid_before(valid_from)
.not_valid_after(valid_until)
.serial_number(x509.random_serial_number())
.add_extension(
x509.SubjectKeyIdentifier.from_public_key(pubkey),
critical=False,
)
)
@staticmethod
def _add_ca_usages(csr: Any) -> Any:
return csr.add_extension(
x509.BasicConstraints(ca=True, path_length=9),
critical=True,
).add_extension(
x509.KeyUsage(
digital_signature=True,
content_commitment=False,
key_encipherment=False,
data_encipherment=False,
key_agreement=False,
key_cert_sign=True,
crl_sign=True,
encipher_only=False,
decipher_only=False),
critical=True
).add_extension(
x509.ExtendedKeyUsage([
ExtendedKeyUsageOID.CLIENT_AUTH,
ExtendedKeyUsageOID.SERVER_AUTH,
ExtendedKeyUsageOID.CODE_SIGNING,
]),
critical=True
)
@staticmethod
def _add_leaf_usages(csr: Any, domains: List[str], issuer: Credentials) -> Any:
names = []
for name in domains:
m = re.match(r'dns:(.+)', name)
if m:
names.append(x509.DNSName(m.group(1)))
else:
try:
names.append(x509.IPAddress(ipaddress.ip_address(name)))
# TODO: specify specific exceptions here
except: # noqa: E722
names.append(x509.DNSName(name))
return csr.add_extension(
x509.BasicConstraints(ca=False, path_length=None),
critical=True,
).add_extension(
x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier(
issuer.certificate.extensions.get_extension_for_class(
x509.SubjectKeyIdentifier).value),
critical=False
).add_extension(
x509.SubjectAlternativeName(names), critical=True,
).add_extension(
x509.ExtendedKeyUsage([
ExtendedKeyUsageOID.SERVER_AUTH,
]),
critical=False
)
@staticmethod
def _add_client_usages(csr: Any, issuer: Credentials, rfc82name: Optional[str] = None) -> Any:
cert = csr.add_extension(
x509.BasicConstraints(ca=False, path_length=None),
critical=True,
).add_extension(
x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier(
issuer.certificate.extensions.get_extension_for_class(
x509.SubjectKeyIdentifier).value),
critical=False
)
if rfc82name:
cert.add_extension(
x509.SubjectAlternativeName([x509.RFC822Name(rfc82name)]),
critical=True,
)
cert.add_extension(
x509.ExtendedKeyUsage([
ExtendedKeyUsageOID.CLIENT_AUTH,
]),
critical=True
)
return cert
@staticmethod
def _make_ca_credentials(name, key_type: Any,
issuer: Optional[Credentials] = None,
valid_from: timedelta = timedelta(days=-1),
valid_to: timedelta = timedelta(days=89),
) -> Credentials:
pkey = _private_key(key_type=key_type)
if issuer is not None:
issuer_subject = issuer.certificate.subject
issuer_key = issuer.private_key
else:
issuer_subject = None
issuer_key = pkey
subject = TestCA._make_x509_name(org_name=name, parent=issuer.subject if issuer else None)
csr = TestCA._make_csr(subject=subject,
issuer_subject=issuer_subject, pkey=pkey,
valid_from_delta=valid_from, valid_until_delta=valid_to)
csr = TestCA._add_ca_usages(csr)
cert = csr.sign(private_key=issuer_key,
algorithm=hashes.SHA256(),
backend=default_backend())
return Credentials(name=name, cert=cert, pkey=pkey, issuer=issuer)
@staticmethod
def _make_server_credentials(name: str, domains: List[str], issuer: Credentials,
key_type: Any,
valid_from: timedelta = timedelta(days=-1),
valid_to: timedelta = timedelta(days=89),
) -> Credentials:
pkey = _private_key(key_type=key_type)
subject = TestCA._make_x509_name(common_name=name, parent=issuer.subject)
csr = TestCA._make_csr(subject=subject,
issuer_subject=issuer.certificate.subject, pkey=pkey,
valid_from_delta=valid_from, valid_until_delta=valid_to)
csr = TestCA._add_leaf_usages(csr, domains=domains, issuer=issuer)
cert = csr.sign(private_key=issuer.private_key,
algorithm=hashes.SHA256(),
backend=default_backend())
return Credentials(name=name, cert=cert, pkey=pkey, issuer=issuer)
@staticmethod
def _make_client_credentials(name: str,
issuer: Credentials, email: Optional[str],
key_type: Any,
valid_from: timedelta = timedelta(days=-1),
valid_to: timedelta = timedelta(days=89),
) -> Credentials:
pkey = _private_key(key_type=key_type)
subject = TestCA._make_x509_name(common_name=name, parent=issuer.subject)
csr = TestCA._make_csr(subject=subject,
issuer_subject=issuer.certificate.subject, pkey=pkey,
valid_from_delta=valid_from, valid_until_delta=valid_to)
csr = TestCA._add_client_usages(csr, issuer=issuer, rfc82name=email)
cert = csr.sign(private_key=issuer.private_key,
algorithm=hashes.SHA256(),
backend=default_backend())
return Credentials(name=name, cert=cert, pkey=pkey, issuer=issuer)