community.crypto/plugins/module_utils/crypto/module_backends/certificate_info.py

# Copyright (c) 2016-2017, Yanis Guenane <yanis+ansible@guenane.org>
# Copyright (c) 2017, Markus Teufelberger <mteufelberger+ansible@mgit.at>
# Copyright (c) 2020, Felix Fontein <felix@fontein.de>
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later

from __future__ import annotations

import abc
import binascii
import traceback

from ansible.module_utils import six
from ansible.module_utils.basic import missing_required_lib
from ansible.module_utils.common.text.converters import to_native
from ansible_collections.community.crypto.plugins.module_utils.crypto.cryptography_support import (
    CRYPTOGRAPHY_TIMEZONE,
    cryptography_decode_name,
    cryptography_get_extensions_from_cert,
    cryptography_oid_to_name,
    cryptography_serial_number_of_cert,
    get_not_valid_after,
    get_not_valid_before,
)
from ansible_collections.community.crypto.plugins.module_utils.crypto.module_backends.publickey_info import (
    get_publickey_info,
)
from ansible_collections.community.crypto.plugins.module_utils.crypto.support import (
    get_fingerprint_of_bytes,
    load_certificate,
)
from ansible_collections.community.crypto.plugins.module_utils.time import (
    get_now_datetime,
)
from ansible_collections.community.crypto.plugins.module_utils.version import (
    LooseVersion,
)


MINIMAL_CRYPTOGRAPHY_VERSION = "1.6"

CRYPTOGRAPHY_IMP_ERR = None
try:
    import cryptography
    from cryptography import x509
    from cryptography.hazmat.primitives import serialization

    CRYPTOGRAPHY_VERSION = LooseVersion(cryptography.__version__)
except ImportError:
    CRYPTOGRAPHY_IMP_ERR = traceback.format_exc()
    CRYPTOGRAPHY_FOUND = False
else:
    CRYPTOGRAPHY_FOUND = True


TIMESTAMP_FORMAT = "%Y%m%d%H%M%SZ"


@six.add_metaclass(abc.ABCMeta)
class CertificateInfoRetrieval:
    def __init__(self, module, backend, content):
        # content must be a bytes string
        self.module = module
        self.backend = backend
        self.content = content

    @abc.abstractmethod
    def _get_der_bytes(self):
        pass

    @abc.abstractmethod
    def _get_signature_algorithm(self):
        pass

    @abc.abstractmethod
    def _get_subject_ordered(self):
        pass

    @abc.abstractmethod
    def _get_issuer_ordered(self):
        pass

    @abc.abstractmethod
    def _get_version(self):
        pass

    @abc.abstractmethod
    def _get_key_usage(self):
        pass

    @abc.abstractmethod
    def _get_extended_key_usage(self):
        pass

    @abc.abstractmethod
    def _get_basic_constraints(self):
        pass

    @abc.abstractmethod
    def _get_ocsp_must_staple(self):
        pass

    @abc.abstractmethod
    def _get_subject_alt_name(self):
        pass

    @abc.abstractmethod
    def get_not_before(self):
        pass

    @abc.abstractmethod
    def get_not_after(self):
        pass

    @abc.abstractmethod
    def _get_public_key_pem(self):
        pass

    @abc.abstractmethod
    def _get_public_key_object(self):
        pass

    @abc.abstractmethod
    def _get_subject_key_identifier(self):
        pass

    @abc.abstractmethod
    def _get_authority_key_identifier(self):
        pass

    @abc.abstractmethod
    def _get_serial_number(self):
        pass

    @abc.abstractmethod
    def _get_all_extensions(self):
        pass

    @abc.abstractmethod
    def _get_ocsp_uri(self):
        pass

    @abc.abstractmethod
    def _get_issuer_uri(self):
        pass

    def get_info(self, prefer_one_fingerprint=False, der_support_enabled=False):
        result = dict()
        self.cert = load_certificate(
            None,
            content=self.content,
            backend=self.backend,
            der_support_enabled=der_support_enabled,
        )

        result["signature_algorithm"] = self._get_signature_algorithm()
        subject = self._get_subject_ordered()
        issuer = self._get_issuer_ordered()
        result["subject"] = dict()
        for k, v in subject:
            result["subject"][k] = v
        result["subject_ordered"] = subject
        result["issuer"] = dict()
        for k, v in issuer:
            result["issuer"][k] = v
        result["issuer_ordered"] = issuer
        result["version"] = self._get_version()
        result["key_usage"], result["key_usage_critical"] = self._get_key_usage()
        result["extended_key_usage"], result["extended_key_usage_critical"] = (
            self._get_extended_key_usage()
        )
        result["basic_constraints"], result["basic_constraints_critical"] = (
            self._get_basic_constraints()
        )
        result["ocsp_must_staple"], result["ocsp_must_staple_critical"] = (
            self._get_ocsp_must_staple()
        )
        result["subject_alt_name"], result["subject_alt_name_critical"] = (
            self._get_subject_alt_name()
        )

        not_before = self.get_not_before()
        not_after = self.get_not_after()
        result["not_before"] = not_before.strftime(TIMESTAMP_FORMAT)
        result["not_after"] = not_after.strftime(TIMESTAMP_FORMAT)
        result["expired"] = not_after < get_now_datetime(
            with_timezone=CRYPTOGRAPHY_TIMEZONE
        )

        result["public_key"] = to_native(self._get_public_key_pem())

        public_key_info = get_publickey_info(
            self.module,
            self.backend,
            key=self._get_public_key_object(),
            prefer_one_fingerprint=prefer_one_fingerprint,
        )
        result.update(
            {
                "public_key_type": public_key_info["type"],
                "public_key_data": public_key_info["public_data"],
                "public_key_fingerprints": public_key_info["fingerprints"],
            }
        )

        result["fingerprints"] = get_fingerprint_of_bytes(
            self._get_der_bytes(), prefer_one=prefer_one_fingerprint
        )

        ski = self._get_subject_key_identifier()
        if ski is not None:
            ski = to_native(binascii.hexlify(ski))
            ski = ":".join([ski[i : i + 2] for i in range(0, len(ski), 2)])
        result["subject_key_identifier"] = ski

        aki, aci, acsn = self._get_authority_key_identifier()
        if aki is not None:
            aki = to_native(binascii.hexlify(aki))
            aki = ":".join([aki[i : i + 2] for i in range(0, len(aki), 2)])
        result["authority_key_identifier"] = aki
        result["authority_cert_issuer"] = aci
        result["authority_cert_serial_number"] = acsn

        result["serial_number"] = self._get_serial_number()
        result["extensions_by_oid"] = self._get_all_extensions()
        result["ocsp_uri"] = self._get_ocsp_uri()
        result["issuer_uri"] = self._get_issuer_uri()

        return result


class CertificateInfoRetrievalCryptography(CertificateInfoRetrieval):
    """Validate the supplied cert, using the cryptography backend"""

    def __init__(self, module, content):
        super(CertificateInfoRetrievalCryptography, self).__init__(
            module, "cryptography", content
        )
        self.name_encoding = module.params.get("name_encoding", "ignore")

    def _get_der_bytes(self):
        return self.cert.public_bytes(serialization.Encoding.DER)

    def _get_signature_algorithm(self):
        return cryptography_oid_to_name(self.cert.signature_algorithm_oid)

    def _get_subject_ordered(self):
        result = []
        for attribute in self.cert.subject:
            result.append([cryptography_oid_to_name(attribute.oid), attribute.value])
        return result

    def _get_issuer_ordered(self):
        result = []
        for attribute in self.cert.issuer:
            result.append([cryptography_oid_to_name(attribute.oid), attribute.value])
        return result

    def _get_version(self):
        if self.cert.version == x509.Version.v1:
            return 1
        if self.cert.version == x509.Version.v3:
            return 3
        return "unknown"

    def _get_key_usage(self):
        try:
            current_key_ext = self.cert.extensions.get_extension_for_class(
                x509.KeyUsage
            )
            current_key_usage = current_key_ext.value
            key_usage = dict(
                digital_signature=current_key_usage.digital_signature,
                content_commitment=current_key_usage.content_commitment,
                key_encipherment=current_key_usage.key_encipherment,
                data_encipherment=current_key_usage.data_encipherment,
                key_agreement=current_key_usage.key_agreement,
                key_cert_sign=current_key_usage.key_cert_sign,
                crl_sign=current_key_usage.crl_sign,
                encipher_only=False,
                decipher_only=False,
            )
            if key_usage["key_agreement"]:
                key_usage.update(
                    dict(
                        encipher_only=current_key_usage.encipher_only,
                        decipher_only=current_key_usage.decipher_only,
                    )
                )

            key_usage_names = dict(
                digital_signature="Digital Signature",
                content_commitment="Non Repudiation",
                key_encipherment="Key Encipherment",
                data_encipherment="Data Encipherment",
                key_agreement="Key Agreement",
                key_cert_sign="Certificate Sign",
                crl_sign="CRL Sign",
                encipher_only="Encipher Only",
                decipher_only="Decipher Only",
            )
            return (
                sorted(
                    [
                        key_usage_names[name]
                        for name, value in key_usage.items()
                        if value
                    ]
                ),
                current_key_ext.critical,
            )
        except cryptography.x509.ExtensionNotFound:
            return None, False

    def _get_extended_key_usage(self):
        try:
            ext_keyusage_ext = self.cert.extensions.get_extension_for_class(
                x509.ExtendedKeyUsage
            )
            return (
                sorted(
                    [cryptography_oid_to_name(eku) for eku in ext_keyusage_ext.value]
                ),
                ext_keyusage_ext.critical,
            )
        except cryptography.x509.ExtensionNotFound:
            return None, False

    def _get_basic_constraints(self):
        try:
            ext_keyusage_ext = self.cert.extensions.get_extension_for_class(
                x509.BasicConstraints
            )
            result = []
            result.append(f"CA:{'TRUE' if ext_keyusage_ext.value.ca else 'FALSE'}")
            if ext_keyusage_ext.value.path_length is not None:
                result.append(f"pathlen:{ext_keyusage_ext.value.path_length}")
            return sorted(result), ext_keyusage_ext.critical
        except cryptography.x509.ExtensionNotFound:
            return None, False

    def _get_ocsp_must_staple(self):
        try:
            try:
                # This only works with cryptography >= 2.1
                tlsfeature_ext = self.cert.extensions.get_extension_for_class(
                    x509.TLSFeature
                )
                value = (
                    cryptography.x509.TLSFeatureType.status_request
                    in tlsfeature_ext.value
                )
            except AttributeError:
                # Fallback for cryptography < 2.1
                oid = x509.oid.ObjectIdentifier("1.3.6.1.5.5.7.1.24")
                tlsfeature_ext = self.cert.extensions.get_extension_for_oid(oid)
                value = tlsfeature_ext.value.value == b"\x30\x03\x02\x01\x05"
            return value, tlsfeature_ext.critical
        except cryptography.x509.ExtensionNotFound:
            return None, False

    def _get_subject_alt_name(self):
        try:
            san_ext = self.cert.extensions.get_extension_for_class(
                x509.SubjectAlternativeName
            )
            result = [
                cryptography_decode_name(san, idn_rewrite=self.name_encoding)
                for san in san_ext.value
            ]
            return result, san_ext.critical
        except cryptography.x509.ExtensionNotFound:
            return None, False

    def get_not_before(self):
        return get_not_valid_before(self.cert)

    def get_not_after(self):
        return get_not_valid_after(self.cert)

    def _get_public_key_pem(self):
        return self.cert.public_key().public_bytes(
            serialization.Encoding.PEM,
            serialization.PublicFormat.SubjectPublicKeyInfo,
        )

    def _get_public_key_object(self):
        return self.cert.public_key()

    def _get_subject_key_identifier(self):
        try:
            ext = self.cert.extensions.get_extension_for_class(
                x509.SubjectKeyIdentifier
            )
            return ext.value.digest
        except cryptography.x509.ExtensionNotFound:
            return None

    def _get_authority_key_identifier(self):
        try:
            ext = self.cert.extensions.get_extension_for_class(
                x509.AuthorityKeyIdentifier
            )
            issuer = None
            if ext.value.authority_cert_issuer is not None:
                issuer = [
                    cryptography_decode_name(san, idn_rewrite=self.name_encoding)
                    for san in ext.value.authority_cert_issuer
                ]
            return (
                ext.value.key_identifier,
                issuer,
                ext.value.authority_cert_serial_number,
            )
        except cryptography.x509.ExtensionNotFound:
            return None, None, None

    def _get_serial_number(self):
        return cryptography_serial_number_of_cert(self.cert)

    def _get_all_extensions(self):
        return cryptography_get_extensions_from_cert(self.cert)

    def _get_ocsp_uri(self):
        try:
            ext = self.cert.extensions.get_extension_for_class(
                x509.AuthorityInformationAccess
            )
            for desc in ext.value:
                if desc.access_method == x509.oid.AuthorityInformationAccessOID.OCSP:
                    if isinstance(desc.access_location, x509.UniformResourceIdentifier):
                        return desc.access_location.value
        except x509.ExtensionNotFound:
            pass
        return None

    def _get_issuer_uri(self):
        try:
            ext = self.cert.extensions.get_extension_for_class(
                x509.AuthorityInformationAccess
            )
            for desc in ext.value:
                if (
                    desc.access_method
                    == x509.oid.AuthorityInformationAccessOID.CA_ISSUERS
                ):
                    if isinstance(desc.access_location, x509.UniformResourceIdentifier):
                        return desc.access_location.value
        except x509.ExtensionNotFound:
            pass
        return None


def get_certificate_info(module, backend, content, prefer_one_fingerprint=False):
    if backend == "cryptography":
        info = CertificateInfoRetrievalCryptography(module, content)
    return info.get_info(prefer_one_fingerprint=prefer_one_fingerprint)


def select_backend(module, backend, content):
    if backend == "auto":
        # Detection what is possible
        can_use_cryptography = (
            CRYPTOGRAPHY_FOUND
            and CRYPTOGRAPHY_VERSION >= LooseVersion(MINIMAL_CRYPTOGRAPHY_VERSION)
        )

        # Try cryptography
        if can_use_cryptography:
            backend = "cryptography"

        # Success?
        if backend == "auto":
            module.fail_json(
                msg=f"Cannot detect any of the required Python libraries cryptography (>= {MINIMAL_CRYPTOGRAPHY_VERSION})"
            )

    if backend == "cryptography":
        if not CRYPTOGRAPHY_FOUND:
            module.fail_json(
                msg=missing_required_lib(
                    f"cryptography >= {MINIMAL_CRYPTOGRAPHY_VERSION}"
                ),
                exception=CRYPTOGRAPHY_IMP_ERR,
            )
        return backend, CertificateInfoRetrievalCryptography(module, content)
    else:
        raise ValueError(f"Unsupported value for backend: {backend}")