#!/usr/bin/python
# -*- coding: utf-8 -*-

# Copyrigt: (c) 2017, Yanis Guenane <yanis+ansible@guenane.org>
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)

from __future__ import absolute_import, division, print_function
__metaclass__ = type

ANSIBLE_METADATA = {'metadata_version': '1.1',
                    'status': ['preview'],
                    'supported_by': 'community'}

DOCUMENTATION = r'''
---
module: openssl_csr
version_added: '2.4'
short_description: Generate OpenSSL Certificate Signing Request (CSR)
description:
    - This module allows one to (re)generate OpenSSL certificate signing requests.
    - It uses the pyOpenSSL python library to interact with openssl. This module supports
      the subjectAltName, keyUsage, extendedKeyUsage, basicConstraints and OCSP Must Staple
      extensions.
    - "Please note that the module regenerates existing CSR if it doesn't match the module's
      options, or if it seems to be corrupt. If you are concerned that this could overwrite
      your existing CSR, consider using the I(backup) option."
requirements:
    - Either cryptography >= 1.3
    - Or pyOpenSSL >= 0.15
author:
- Yanis Guenane (@Spredzy)
options:
    state:
        description:
            - Whether the certificate signing request should exist or not, taking action if the state is different from what is stated.
        type: str
        default: present
        choices: [ absent, present ]
    digest:
        description:
            - The digest used when signing the certificate signing request with the private key.
        type: str
        default: sha256
    privatekey_path:
        description:
            - The path to the private key to use when signing the certificate signing request.
        type: path
        required: true
    privatekey_passphrase:
        description:
            - The passphrase for the private key.
            - This is required if the private key is password protected.
        type: str
    version:
        description:
            - The version of the certificate signing request.
        type: int
        default: 1
    force:
        description:
            - Should the certificate signing request be forced regenerated by this ansible module.
        type: bool
        default: no
    path:
        description:
            - The name of the file into which the generated OpenSSL certificate signing request will be written.
        type: path
        required: true
    subject:
        description:
            - Key/value pairs that will be present in the subject name field of the certificate signing request.
            - If you need to specify more than one value with the same key, use a list as value.
        type: dict
        version_added: '2.5'
    country_name:
        description:
            - The countryName field of the certificate signing request subject.
        type: str
        aliases: [ C, countryName ]
    state_or_province_name:
        description:
            - The stateOrProvinceName field of the certificate signing request subject.
        type: str
        aliases: [ ST, stateOrProvinceName ]
    locality_name:
        description:
            - The localityName field of the certificate signing request subject.
        type: str
        aliases: [ L, localityName ]
    organization_name:
        description:
            - The organizationName field of the certificate signing request subject.
        type: str
        aliases: [ O, organizationName ]
    organizational_unit_name:
        description:
            - The organizationalUnitName field of the certificate signing request subject.
        type: str
        aliases: [ OU, organizationalUnitName ]
    common_name:
        description:
            - The commonName field of the certificate signing request subject.
        type: str
        aliases: [ CN, commonName ]
    email_address:
        description:
            - The emailAddress field of the certificate signing request subject.
        type: str
        aliases: [ E, emailAddress ]
    subject_alt_name:
        description:
            - SAN extension to attach to the certificate signing request.
            - This can either be a 'comma separated string' or a YAML list.
            - Values must be prefixed by their options. (i.e., C(email), C(URI), C(DNS), C(RID), C(IP), C(dirName),
              C(otherName) and the ones specific to your CA)
            - Note that if no SAN is specified, but a common name, the common
              name will be added as a SAN except if C(useCommonNameForSAN) is
              set to I(false).
            - More at U(https://tools.ietf.org/html/rfc5280#section-4.2.1.6).
        type: list
        aliases: [ subjectAltName ]
    subject_alt_name_critical:
        description:
            - Should the subjectAltName extension be considered as critical.
        type: bool
        aliases: [ subjectAltName_critical ]
    use_common_name_for_san:
        description:
            - If set to C(yes), the module will fill the common name in for
              C(subject_alt_name) with C(DNS:) prefix if no SAN is specified.
        type: bool
        default: yes
        version_added: '2.8'
        aliases: [ useCommonNameForSAN ]
    key_usage:
        description:
            - This defines the purpose (e.g. encipherment, signature, certificate signing)
              of the key contained in the certificate.
        type: list
        aliases: [ keyUsage ]
    key_usage_critical:
        description:
            - Should the keyUsage extension be considered as critical.
        type: bool
        aliases: [ keyUsage_critical ]
    extended_key_usage:
        description:
            - Additional restrictions (e.g. client authentication, server authentication)
              on the allowed purposes for which the public key may be used.
        type: list
        aliases: [ extKeyUsage, extendedKeyUsage ]
    extended_key_usage_critical:
        description:
            - Should the extkeyUsage extension be considered as critical.
        type: bool
        aliases: [ extKeyUsage_critical, extendedKeyUsage_critical ]
    basic_constraints:
        description:
            - Indicates basic constraints, such as if the certificate is a CA.
        type: list
        version_added: '2.5'
        aliases: [ basicConstraints ]
    basic_constraints_critical:
        description:
            - Should the basicConstraints extension be considered as critical.
        type: bool
        version_added: '2.5'
        aliases: [ basicConstraints_critical ]
    ocsp_must_staple:
        description:
            - Indicates that the certificate should contain the OCSP Must Staple
              extension (U(https://tools.ietf.org/html/rfc7633)).
        type: bool
        version_added: '2.5'
        aliases: [ ocspMustStaple ]
    ocsp_must_staple_critical:
        description:
            - Should the OCSP Must Staple extension be considered as critical
            - Note that according to the RFC, this extension should not be marked
              as critical, as old clients not knowing about OCSP Must Staple
              are required to reject such certificates
              (see U(https://tools.ietf.org/html/rfc7633#section-4)).
        type: bool
        version_added: '2.5'
        aliases: [ ocspMustStaple_critical ]
    select_crypto_backend:
        description:
            - Determines which crypto backend to use.
            - The default choice is C(auto), which tries to use C(cryptography) if available, and falls back to C(pyopenssl).
            - If set to C(pyopenssl), will try to use the L(pyOpenSSL,https://pypi.org/project/pyOpenSSL/) library.
            - If set to C(cryptography), will try to use the L(cryptography,https://cryptography.io/) library.
        type: str
        default: auto
        choices: [ auto, cryptography, pyopenssl ]
        version_added: '2.8'
    backup:
        description:
            - Create a backup file including a timestamp so you can get the original
              CSR back if you overwrote it with a new one by accident.
        type: bool
        default: no
        version_added: "2.8"
extends_documentation_fragment:
- files
notes:
    - If the certificate signing request already exists it will be checked whether subjectAltName,
      keyUsage, extendedKeyUsage and basicConstraints only contain the requested values, whether
      OCSP Must Staple is as requested, and if the request was signed by the given private key.
seealso:
- module: openssl_certificate
- module: openssl_dhparam
- module: openssl_pkcs12
- module: openssl_privatekey
- module: openssl_publickey
'''

EXAMPLES = r'''
- name: Generate an OpenSSL Certificate Signing Request
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    common_name: www.ansible.com

- name: Generate an OpenSSL Certificate Signing Request with a passphrase protected private key
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    privatekey_passphrase: ansible
    common_name: www.ansible.com

- name: Generate an OpenSSL Certificate Signing Request with Subject information
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    country_name: FR
    organization_name: Ansible
    email_address: jdoe@ansible.com
    common_name: www.ansible.com

- name: Generate an OpenSSL Certificate Signing Request with subjectAltName extension
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    subject_alt_name: 'DNS:www.ansible.com,DNS:m.ansible.com'

- name: Generate an OpenSSL CSR with subjectAltName extension with dynamic list
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    subject_alt_name: "{{ item.value | map('regex_replace', '^', 'DNS:') | list }}"
  with_dict:
    dns_server:
    - www.ansible.com
    - m.ansible.com

- name: Force regenerate an OpenSSL Certificate Signing Request
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    force: yes
    common_name: www.ansible.com

- name: Generate an OpenSSL Certificate Signing Request with special key usages
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    common_name: www.ansible.com
    key_usage:
      - digitalSignature
      - keyAgreement
    extended_key_usage:
      - clientAuth

- name: Generate an OpenSSL Certificate Signing Request with OCSP Must Staple
  openssl_csr:
    path: /etc/ssl/csr/www.ansible.com.csr
    privatekey_path: /etc/ssl/private/ansible.com.pem
    common_name: www.ansible.com
    ocsp_must_staple: yes
'''

RETURN = r'''
privatekey:
    description: Path to the TLS/SSL private key the CSR was generated for
    returned: changed or success
    type: str
    sample: /etc/ssl/private/ansible.com.pem
filename:
    description: Path to the generated Certificate Signing Request
    returned: changed or success
    type: str
    sample: /etc/ssl/csr/www.ansible.com.csr
subject:
    description: A list of the subject tuples attached to the CSR
    returned: changed or success
    type: list
    sample: "[('CN', 'www.ansible.com'), ('O', 'Ansible')]"
subjectAltName:
    description: The alternative names this CSR is valid for
    returned: changed or success
    type: list
    sample: [ 'DNS:www.ansible.com', 'DNS:m.ansible.com' ]
keyUsage:
    description: Purpose for which the public key may be used
    returned: changed or success
    type: list
    sample: [ 'digitalSignature', 'keyAgreement' ]
extendedKeyUsage:
    description: Additional restriction on the public key purposes
    returned: changed or success
    type: list
    sample: [ 'clientAuth' ]
basicConstraints:
    description: Indicates if the certificate belongs to a CA
    returned: changed or success
    type: list
    sample: ['CA:TRUE', 'pathLenConstraint:0']
ocsp_must_staple:
    description: Indicates whether the certificate has the OCSP
                 Must Staple feature enabled
    returned: changed or success
    type: bool
    sample: false
backup_file:
    description: Name of backup file created.
    returned: changed and if I(backup) is C(yes)
    type: str
    sample: /path/to/www.ansible.com.csr.2019-03-09@11:22~
'''

import abc
import os
import traceback
from distutils.version import LooseVersion

from ansible.module_utils import crypto as crypto_utils
from ansible.module_utils.basic import AnsibleModule, missing_required_lib
from ansible.module_utils._text import to_native, to_bytes, to_text
from ansible.module_utils.compat import ipaddress as compat_ipaddress

MINIMAL_PYOPENSSL_VERSION = '0.15'
MINIMAL_CRYPTOGRAPHY_VERSION = '1.3'

PYOPENSSL_IMP_ERR = None
try:
    import OpenSSL
    from OpenSSL import crypto
    PYOPENSSL_VERSION = LooseVersion(OpenSSL.__version__)
except ImportError:
    PYOPENSSL_IMP_ERR = traceback.format_exc()
    PYOPENSSL_FOUND = False
else:
    PYOPENSSL_FOUND = True
    if OpenSSL.SSL.OPENSSL_VERSION_NUMBER >= 0x10100000:
        # OpenSSL 1.1.0 or newer
        OPENSSL_MUST_STAPLE_NAME = b"tlsfeature"
        OPENSSL_MUST_STAPLE_VALUE = b"status_request"
    else:
        # OpenSSL 1.0.x or older
        OPENSSL_MUST_STAPLE_NAME = b"1.3.6.1.5.5.7.1.24"
        OPENSSL_MUST_STAPLE_VALUE = b"DER:30:03:02:01:05"

CRYPTOGRAPHY_IMP_ERR = None
try:
    import cryptography
    import cryptography.x509
    import cryptography.x509.oid
    import cryptography.exceptions
    import cryptography.hazmat.backends
    import cryptography.hazmat.primitives.serialization
    import cryptography.hazmat.primitives.hashes
    CRYPTOGRAPHY_VERSION = LooseVersion(cryptography.__version__)
except ImportError:
    CRYPTOGRAPHY_IMP_ERR = traceback.format_exc()
    CRYPTOGRAPHY_FOUND = False
else:
    CRYPTOGRAPHY_FOUND = True
    CRYPTOGRAPHY_MUST_STAPLE_NAME = cryptography.x509.oid.ObjectIdentifier("1.3.6.1.5.5.7.1.24")
    CRYPTOGRAPHY_MUST_STAPLE_VALUE = b"\x30\x03\x02\x01\x05"


class CertificateSigningRequestError(crypto_utils.OpenSSLObjectError):
    pass


class CertificateSigningRequestBase(crypto_utils.OpenSSLObject):

    def __init__(self, module):
        super(CertificateSigningRequestBase, self).__init__(
            module.params['path'],
            module.params['state'],
            module.params['force'],
            module.check_mode
        )
        self.digest = module.params['digest']
        self.privatekey_path = module.params['privatekey_path']
        self.privatekey_passphrase = module.params['privatekey_passphrase']
        self.version = module.params['version']
        self.subjectAltName = module.params['subject_alt_name']
        self.subjectAltName_critical = module.params['subject_alt_name_critical']
        self.keyUsage = module.params['key_usage']
        self.keyUsage_critical = module.params['key_usage_critical']
        self.extendedKeyUsage = module.params['extended_key_usage']
        self.extendedKeyUsage_critical = module.params['extended_key_usage_critical']
        self.basicConstraints = module.params['basic_constraints']
        self.basicConstraints_critical = module.params['basic_constraints_critical']
        self.ocspMustStaple = module.params['ocsp_must_staple']
        self.ocspMustStaple_critical = module.params['ocsp_must_staple_critical']
        self.request = None
        self.privatekey = None

        self.backup = module.params['backup']
        self.backup_file = None

        self.subject = [
            ('C', module.params['country_name']),
            ('ST', module.params['state_or_province_name']),
            ('L', module.params['locality_name']),
            ('O', module.params['organization_name']),
            ('OU', module.params['organizational_unit_name']),
            ('CN', module.params['common_name']),
            ('emailAddress', module.params['email_address']),
        ]

        if module.params['subject']:
            self.subject = self.subject + crypto_utils.parse_name_field(module.params['subject'])
        self.subject = [(entry[0], entry[1]) for entry in self.subject if entry[1]]

        if not self.subjectAltName and module.params['use_common_name_for_san']:
            for sub in self.subject:
                if sub[0] in ('commonName', 'CN'):
                    self.subjectAltName = ['DNS:%s' % sub[1]]
                    break

    @abc.abstractmethod
    def _generate_csr(self):
        pass

    def generate(self, module):
        '''Generate the certificate signing request.'''
        if not self.check(module, perms_required=False) or self.force:
            result = self._generate_csr()
            if self.backup:
                self.backup_file = module.backup_local(self.path)
            crypto_utils.write_file(module, result)
            self.changed = True

        file_args = module.load_file_common_arguments(module.params)
        if module.set_fs_attributes_if_different(file_args, False):
            self.changed = True

    @abc.abstractmethod
    def _load_private_key(self):
        pass

    @abc.abstractmethod
    def _check_csr(self):
        pass

    def check(self, module, perms_required=True):
        """Ensure the resource is in its desired state."""
        state_and_perms = super(CertificateSigningRequestBase, self).check(module, perms_required)

        self._load_private_key()

        if not state_and_perms:
            return False

        return self._check_csr()

    def remove(self, module):
        if self.backup:
            self.backup_file = module.backup_local(self.path)
        super(CertificateSigningRequestBase, self).remove(module)

    def dump(self):
        '''Serialize the object into a dictionary.'''

        result = {
            'privatekey': self.privatekey_path,
            'filename': self.path,
            'subject': self.subject,
            'subjectAltName': self.subjectAltName,
            'keyUsage': self.keyUsage,
            'extendedKeyUsage': self.extendedKeyUsage,
            'basicConstraints': self.basicConstraints,
            'ocspMustStaple': self.ocspMustStaple,
            'changed': self.changed
        }
        if self.backup_file:
            result['backup_file'] = self.backup_file

        return result


class CertificateSigningRequestPyOpenSSL(CertificateSigningRequestBase):

    def __init__(self, module):
        super(CertificateSigningRequestPyOpenSSL, self).__init__(module)

    def _generate_csr(self):
        req = crypto.X509Req()
        req.set_version(self.version - 1)
        subject = req.get_subject()
        for entry in self.subject:
            if entry[1] is not None:
                # Workaround for https://github.com/pyca/pyopenssl/issues/165
                nid = OpenSSL._util.lib.OBJ_txt2nid(to_bytes(entry[0]))
                if nid == 0:
                    raise CertificateSigningRequestError('Unknown subject field identifier "{0}"'.format(entry[0]))
                res = OpenSSL._util.lib.X509_NAME_add_entry_by_NID(subject._name, nid, OpenSSL._util.lib.MBSTRING_UTF8, to_bytes(entry[1]), -1, -1, 0)
                if res == 0:
                    raise CertificateSigningRequestError('Invalid value for subject field identifier "{0}": {1}'.format(entry[0], entry[1]))

        extensions = []
        if self.subjectAltName:
            altnames = ', '.join(self.subjectAltName)
            try:
                extensions.append(crypto.X509Extension(b"subjectAltName", self.subjectAltName_critical, altnames.encode('ascii')))
            except OpenSSL.crypto.Error as e:
                raise CertificateSigningRequestError(
                    'Error while parsing Subject Alternative Names {0} (check for missing type prefix, such as "DNS:"!): {1}'.format(
                        ', '.join(["{0}".format(san) for san in self.subjectAltName]), str(e)
                    )
                )

        if self.keyUsage:
            usages = ', '.join(self.keyUsage)
            extensions.append(crypto.X509Extension(b"keyUsage", self.keyUsage_critical, usages.encode('ascii')))

        if self.extendedKeyUsage:
            usages = ', '.join(self.extendedKeyUsage)
            extensions.append(crypto.X509Extension(b"extendedKeyUsage", self.extendedKeyUsage_critical, usages.encode('ascii')))

        if self.basicConstraints:
            usages = ', '.join(self.basicConstraints)
            extensions.append(crypto.X509Extension(b"basicConstraints", self.basicConstraints_critical, usages.encode('ascii')))

        if self.ocspMustStaple:
            extensions.append(crypto.X509Extension(OPENSSL_MUST_STAPLE_NAME, self.ocspMustStaple_critical, OPENSSL_MUST_STAPLE_VALUE))

        if extensions:
            req.add_extensions(extensions)

        req.set_pubkey(self.privatekey)
        req.sign(self.privatekey, self.digest)
        self.request = req

        return crypto.dump_certificate_request(crypto.FILETYPE_PEM, self.request)

    def _load_private_key(self):
        try:
            self.privatekey = crypto_utils.load_privatekey(self.privatekey_path, self.privatekey_passphrase)
        except crypto_utils.OpenSSLBadPassphraseError as exc:
            raise CertificateSigningRequestError(exc)

    def _normalize_san(self, san):
        # Apparently OpenSSL returns 'IP address' not 'IP' as specifier when converting the subjectAltName to string
        # although it won't accept this specifier when generating the CSR. (https://github.com/openssl/openssl/issues/4004)
        if san.startswith('IP Address:'):
            san = 'IP:' + san[len('IP Address:'):]
        if san.startswith('IP:'):
            ip = compat_ipaddress.ip_address(san[3:])
            san = 'IP:{0}'.format(ip.compressed)
        return san

    def _check_csr(self):
        def _check_subject(csr):
            subject = [(OpenSSL._util.lib.OBJ_txt2nid(to_bytes(sub[0])), to_bytes(sub[1])) for sub in self.subject]
            current_subject = [(OpenSSL._util.lib.OBJ_txt2nid(to_bytes(sub[0])), to_bytes(sub[1])) for sub in csr.get_subject().get_components()]
            if not set(subject) == set(current_subject):
                return False

            return True

        def _check_subjectAltName(extensions):
            altnames_ext = next((ext for ext in extensions if ext.get_short_name() == b'subjectAltName'), '')
            altnames = [self._normalize_san(altname.strip()) for altname in
                        to_text(altnames_ext, errors='surrogate_or_strict').split(',') if altname.strip()]
            if self.subjectAltName:
                if (set(altnames) != set([self._normalize_san(to_text(name)) for name in self.subjectAltName]) or
                        altnames_ext.get_critical() != self.subjectAltName_critical):
                    return False
            else:
                if altnames:
                    return False

            return True

        def _check_keyUsage_(extensions, extName, expected, critical):
            usages_ext = [ext for ext in extensions if ext.get_short_name() == extName]
            if (not usages_ext and expected) or (usages_ext and not expected):
                return False
            elif not usages_ext and not expected:
                return True
            else:
                current = [OpenSSL._util.lib.OBJ_txt2nid(to_bytes(usage.strip())) for usage in str(usages_ext[0]).split(',')]
                expected = [OpenSSL._util.lib.OBJ_txt2nid(to_bytes(usage)) for usage in expected]
                return set(current) == set(expected) and usages_ext[0].get_critical() == critical

        def _check_keyUsage(extensions):
            usages_ext = [ext for ext in extensions if ext.get_short_name() == b'keyUsage']
            if (not usages_ext and self.keyUsage) or (usages_ext and not self.keyUsage):
                return False
            elif not usages_ext and not self.keyUsage:
                return True
            else:
                # OpenSSL._util.lib.OBJ_txt2nid() always returns 0 for all keyUsage values
                # (since keyUsage has a fixed bitfield for these values and is not extensible).
                # Therefore, we create an extension for the wanted values, and compare the
                # data of the extensions (which is the serialized bitfield).
                expected_ext = crypto.X509Extension(b"keyUsage", False, ', '.join(self.keyUsage).encode('ascii'))
                return usages_ext[0].get_data() == expected_ext.get_data() and usages_ext[0].get_critical() == self.keyUsage_critical

        def _check_extenededKeyUsage(extensions):
            return _check_keyUsage_(extensions, b'extendedKeyUsage', self.extendedKeyUsage, self.extendedKeyUsage_critical)

        def _check_basicConstraints(extensions):
            return _check_keyUsage_(extensions, b'basicConstraints', self.basicConstraints, self.basicConstraints_critical)

        def _check_ocspMustStaple(extensions):
            oms_ext = [ext for ext in extensions if to_bytes(ext.get_short_name()) == OPENSSL_MUST_STAPLE_NAME and to_bytes(ext) == OPENSSL_MUST_STAPLE_VALUE]
            if OpenSSL.SSL.OPENSSL_VERSION_NUMBER < 0x10100000:
                # Older versions of libssl don't know about OCSP Must Staple
                oms_ext.extend([ext for ext in extensions if ext.get_short_name() == b'UNDEF' and ext.get_data() == b'\x30\x03\x02\x01\x05'])
            if self.ocspMustStaple:
                return len(oms_ext) > 0 and oms_ext[0].get_critical() == self.ocspMustStaple_critical
            else:
                return len(oms_ext) == 0

        def _check_extensions(csr):
            extensions = csr.get_extensions()
            return (_check_subjectAltName(extensions) and _check_keyUsage(extensions) and
                    _check_extenededKeyUsage(extensions) and _check_basicConstraints(extensions) and
                    _check_ocspMustStaple(extensions))

        def _check_signature(csr):
            try:
                return csr.verify(self.privatekey)
            except crypto.Error:
                return False

        try:
            csr = crypto_utils.load_certificate_request(self.path, backend='pyopenssl')
        except Exception as dummy:
            return False

        return _check_subject(csr) and _check_extensions(csr) and _check_signature(csr)


class CertificateSigningRequestCryptography(CertificateSigningRequestBase):

    def __init__(self, module):
        super(CertificateSigningRequestCryptography, self).__init__(module)
        self.cryptography_backend = cryptography.hazmat.backends.default_backend()

    def _generate_csr(self):
        csr = cryptography.x509.CertificateSigningRequestBuilder()
        try:
            csr = csr.subject_name(cryptography.x509.Name([
                cryptography.x509.NameAttribute(crypto_utils.cryptography_name_to_oid(entry[0]), to_text(entry[1])) for entry in self.subject
            ]))
        except ValueError as e:
            raise CertificateSigningRequestError(e)

        if self.subjectAltName:
            csr = csr.add_extension(cryptography.x509.SubjectAlternativeName([
                crypto_utils.cryptography_get_name(name) for name in self.subjectAltName
            ]), critical=self.subjectAltName_critical)

        if self.keyUsage:
            params = crypto_utils.cryptography_parse_key_usage_params(self.keyUsage)
            csr = csr.add_extension(cryptography.x509.KeyUsage(**params), critical=self.keyUsage_critical)

        if self.extendedKeyUsage:
            usages = [crypto_utils.cryptography_name_to_oid(usage) for usage in self.extendedKeyUsage]
            csr = csr.add_extension(cryptography.x509.ExtendedKeyUsage(usages), critical=self.extendedKeyUsage_critical)

        if self.basicConstraints:
            params = {}
            ca, path_length = crypto_utils.cryptography_get_basic_constraints(self.basicConstraints)
            csr = csr.add_extension(cryptography.x509.BasicConstraints(ca, path_length), critical=self.basicConstraints_critical)

        if self.ocspMustStaple:
            try:
                # This only works with cryptography >= 2.1
                csr = csr.add_extension(cryptography.x509.TLSFeature([cryptography.x509.TLSFeatureType.status_request]), critical=self.ocspMustStaple_critical)
            except AttributeError as dummy:
                csr = csr.add_extension(
                    cryptography.x509.UnrecognizedExtension(CRYPTOGRAPHY_MUST_STAPLE_NAME, CRYPTOGRAPHY_MUST_STAPLE_VALUE),
                    critical=self.ocspMustStaple_critical
                )

        digest = None
        if self.digest == 'sha256':
            digest = cryptography.hazmat.primitives.hashes.SHA256()
        elif self.digest == 'sha384':
            digest = cryptography.hazmat.primitives.hashes.SHA384()
        elif self.digest == 'sha512':
            digest = cryptography.hazmat.primitives.hashes.SHA512()
        elif self.digest == 'sha1':
            digest = cryptography.hazmat.primitives.hashes.SHA1()
        elif self.digest == 'md5':
            digest = cryptography.hazmat.primitives.hashes.MD5()
        # FIXME
        else:
            raise CertificateSigningRequestError('Unsupported digest "{0}"'.format(self.digest))
        self.request = csr.sign(self.privatekey, digest, self.cryptography_backend)

        return self.request.public_bytes(cryptography.hazmat.primitives.serialization.Encoding.PEM)

    def _load_private_key(self):
        try:
            with open(self.privatekey_path, 'rb') as f:
                self.privatekey = cryptography.hazmat.primitives.serialization.load_pem_private_key(
                    f.read(),
                    None if self.privatekey_passphrase is None else to_bytes(self.privatekey_passphrase),
                    backend=self.cryptography_backend
                )
        except Exception as e:
            raise CertificateSigningRequestError(e)

    def _check_csr(self):
        def _check_subject(csr):
            subject = [(crypto_utils.cryptography_name_to_oid(entry[0]), entry[1]) for entry in self.subject]
            current_subject = [(sub.oid, sub.value) for sub in csr.subject]
            return set(subject) == set(current_subject)

        def _find_extension(extensions, type):
            return next(
                (ext for ext in extensions if isinstance(ext.value, type)),
                None
            )

        def _check_subjectAltName(extensions):
            current_altnames_ext = _find_extension(extensions, cryptography.x509.SubjectAlternativeName)
            current_altnames = [str(altname) for altname in current_altnames_ext.value] if current_altnames_ext else []
            altnames = [str(crypto_utils.cryptography_get_name(altname)) for altname in self.subjectAltName] if self.subjectAltName else []
            if set(altnames) != set(current_altnames):
                return False
            if altnames:
                if current_altnames_ext.critical != self.subjectAltName_critical:
                    return False
            return True

        def _check_keyUsage(extensions):
            current_keyusage_ext = _find_extension(extensions, cryptography.x509.KeyUsage)
            if not self.keyUsage:
                return current_keyusage_ext is None
            elif current_keyusage_ext is None:
                return False
            params = crypto_utils.cryptography_parse_key_usage_params(self.keyUsage)
            for param in params:
                if getattr(current_keyusage_ext.value, '_' + param) != params[param]:
                    return False
            if current_keyusage_ext.critical != self.keyUsage_critical:
                return False
            return True

        def _check_extenededKeyUsage(extensions):
            current_usages_ext = _find_extension(extensions, cryptography.x509.ExtendedKeyUsage)
            current_usages = [str(usage) for usage in current_usages_ext.value] if current_usages_ext else []
            usages = [str(crypto_utils.cryptography_name_to_oid(usage)) for usage in self.extendedKeyUsage] if self.extendedKeyUsage else []
            if set(current_usages) != set(usages):
                return False
            if usages:
                if current_usages_ext.critical != self.extendedKeyUsage_critical:
                    return False
            return True

        def _check_basicConstraints(extensions):
            bc_ext = _find_extension(extensions, cryptography.x509.BasicConstraints)
            current_ca = bc_ext.value.ca if bc_ext else False
            current_path_length = bc_ext.value.path_length if bc_ext else None
            ca, path_length = crypto_utils.cryptography_get_basic_constraints(self.basicConstraints)
            # Check CA flag
            if ca != current_ca:
                return False
            # Check path length
            if path_length != current_path_length:
                return False
            # Check criticality
            if self.basicConstraints:
                if bc_ext.critical != self.basicConstraints_critical:
                    return False
            return True

        def _check_ocspMustStaple(extensions):
            try:
                # This only works with cryptography >= 2.1
                tlsfeature_ext = _find_extension(extensions, cryptography.x509.TLSFeature)
                has_tlsfeature = True
            except AttributeError as dummy:
                tlsfeature_ext = next(
                    (ext for ext in extensions if ext.value.oid == CRYPTOGRAPHY_MUST_STAPLE_NAME),
                    None
                )
                has_tlsfeature = False
            if self.ocspMustStaple:
                if not tlsfeature_ext or tlsfeature_ext.critical != self.ocspMustStaple_critical:
                    return False
                if has_tlsfeature:
                    return cryptography.x509.TLSFeatureType.status_request in tlsfeature_ext.value
                else:
                    return tlsfeature_ext.value.value == CRYPTOGRAPHY_MUST_STAPLE_VALUE
            else:
                return tlsfeature_ext is None

        def _check_extensions(csr):
            extensions = csr.extensions
            return (_check_subjectAltName(extensions) and _check_keyUsage(extensions) and
                    _check_extenededKeyUsage(extensions) and _check_basicConstraints(extensions) and
                    _check_ocspMustStaple(extensions))

        def _check_signature(csr):
            if not csr.is_signature_valid:
                return False
            # To check whether public key of CSR belongs to private key,
            # encode both public keys and compare PEMs.
            key_a = csr.public_key().public_bytes(
                cryptography.hazmat.primitives.serialization.Encoding.PEM,
                cryptography.hazmat.primitives.serialization.PublicFormat.SubjectPublicKeyInfo
            )
            key_b = self.privatekey.public_key().public_bytes(
                cryptography.hazmat.primitives.serialization.Encoding.PEM,
                cryptography.hazmat.primitives.serialization.PublicFormat.SubjectPublicKeyInfo
            )
            return key_a == key_b

        try:
            csr = crypto_utils.load_certificate_request(self.path, backend='cryptography')
        except Exception as dummy:
            return False

        return _check_subject(csr) and _check_extensions(csr) and _check_signature(csr)


def main():
    module = AnsibleModule(
        argument_spec=dict(
            state=dict(type='str', default='present', choices=['absent', 'present']),
            digest=dict(type='str', default='sha256'),
            privatekey_path=dict(type='path', require=True),
            privatekey_passphrase=dict(type='str', no_log=True),
            version=dict(type='int', default=1),
            force=dict(type='bool', default=False),
            path=dict(type='path', required=True),
            subject=dict(type='dict'),
            country_name=dict(type='str', aliases=['C', 'countryName']),
            state_or_province_name=dict(type='str', aliases=['ST', 'stateOrProvinceName']),
            locality_name=dict(type='str', aliases=['L', 'localityName']),
            organization_name=dict(type='str', aliases=['O', 'organizationName']),
            organizational_unit_name=dict(type='str', aliases=['OU', 'organizationalUnitName']),
            common_name=dict(type='str', aliases=['CN', 'commonName']),
            email_address=dict(type='str', aliases=['E', 'emailAddress']),
            subject_alt_name=dict(type='list', elements='str', aliases=['subjectAltName']),
            subject_alt_name_critical=dict(type='bool', default=False, aliases=['subjectAltName_critical']),
            use_common_name_for_san=dict(type='bool', default=True, aliases=['useCommonNameForSAN']),
            key_usage=dict(type='list', elements='str', aliases=['keyUsage']),
            key_usage_critical=dict(type='bool', default=False, aliases=['keyUsage_critical']),
            extended_key_usage=dict(type='list', elements='str', aliases=['extKeyUsage', 'extendedKeyUsage']),
            extended_key_usage_critical=dict(type='bool', default=False, aliases=['extKeyUsage_critical', 'extendedKeyUsage_critical']),
            basic_constraints=dict(type='list', elements='str', aliases=['basicConstraints']),
            basic_constraints_critical=dict(type='bool', default=False, aliases=['basicConstraints_critical']),
            ocsp_must_staple=dict(type='bool', default=False, aliases=['ocspMustStaple']),
            ocsp_must_staple_critical=dict(type='bool', default=False, aliases=['ocspMustStaple_critical']),
            backup=dict(type='bool', default=False),
            select_crypto_backend=dict(type='str', default='auto', choices=['auto', 'cryptography', 'pyopenssl']),
        ),
        add_file_common_args=True,
        supports_check_mode=True,
    )

    base_dir = os.path.dirname(module.params['path']) or '.'
    if not os.path.isdir(base_dir):
        module.fail_json(name=base_dir, msg='The directory %s does not exist or the file is not a directory' % base_dir)

    backend = module.params['select_crypto_backend']
    if backend == 'auto':
        # Detection what is possible
        can_use_cryptography = CRYPTOGRAPHY_FOUND and CRYPTOGRAPHY_VERSION >= LooseVersion(MINIMAL_CRYPTOGRAPHY_VERSION)
        can_use_pyopenssl = PYOPENSSL_FOUND and PYOPENSSL_VERSION >= LooseVersion(MINIMAL_PYOPENSSL_VERSION)

        # First try cryptography, then pyOpenSSL
        if can_use_cryptography:
            backend = 'cryptography'
        elif can_use_pyopenssl:
            backend = 'pyopenssl'

        # Success?
        if backend == 'auto':
            module.fail_json(msg=("Can't detect any of the required Python libraries "
                                  "cryptography (>= {0}) or PyOpenSSL (>= {1})").format(
                                      MINIMAL_CRYPTOGRAPHY_VERSION,
                                      MINIMAL_PYOPENSSL_VERSION))
    try:
        if backend == 'pyopenssl':
            if not PYOPENSSL_FOUND:
                module.fail_json(msg=missing_required_lib('pyOpenSSL >= {0}'.format(MINIMAL_PYOPENSSL_VERSION)),
                                 exception=PYOPENSSL_IMP_ERR)
            try:
                getattr(crypto.X509Req, 'get_extensions')
            except AttributeError:
                module.fail_json(msg='You need to have PyOpenSSL>=0.15 to generate CSRs')
            csr = CertificateSigningRequestPyOpenSSL(module)
        elif backend == 'cryptography':
            if not CRYPTOGRAPHY_FOUND:
                module.fail_json(msg=missing_required_lib('cryptography >= {0}'.format(MINIMAL_CRYPTOGRAPHY_VERSION)),
                                 exception=CRYPTOGRAPHY_IMP_ERR)
            csr = CertificateSigningRequestCryptography(module)

        if module.params['state'] == 'present':
            if module.check_mode:
                result = csr.dump()
                result['changed'] = module.params['force'] or not csr.check(module)
                module.exit_json(**result)

            csr.generate(module)

        else:
            if module.check_mode:
                result = csr.dump()
                result['changed'] = os.path.exists(module.params['path'])
                module.exit_json(**result)

            csr.remove(module)

        result = csr.dump()
        module.exit_json(**result)
    except crypto_utils.OpenSSLObjectError as exc:
        module.fail_json(msg=to_native(exc))


if __name__ == "__main__":
    main()
