openssl_privatekey: add ECC support (#49416)

* Add cryptography backend for openssl_privatekey.

* Adding ECC support.

No support for X25519 and X449, since they don't support serialization.

* Improve finterprint calculation to work with Python 3.

* Add fingerprint check.

* Fix typo.

* Use separate curve option for elliptic curves, and use type 'ECC'.

* Using curve names as defined in IANA registry.

* Bump minimal supported cryptography version. Older versions might work as well, but I couldn't test them.

* Improve documentation.

lib/ansible/module_utils/crypto.py

@@ -36,25 +36,44 @@ class OpenSSLObjectError(Exception):
     pass
 
 
-def get_fingerprint(path, passphrase=None):
-    """Generate the fingerprint of the public key. """
+def get_fingerprint_of_bytes(source):
+    """Generate the fingerprint of the given bytes."""
 
     fingerprint = {}
 
-    privatekey = load_privatekey(path, passphrase)
     try:
-        publickey = crypto.dump_publickey(crypto.FILETYPE_ASN1, privatekey)
-        for algo in hashlib.algorithms:
+        algorithms = hashlib.algorithms
+    except AttributeError:
+        try:
+            algorithms = hashlib.algorithms_guaranteed
+        except AttributeError:
+            return None
+
+    for algo in algorithms:
         f = getattr(hashlib, algo)
-            pubkey_digest = f(publickey).hexdigest()
+        h = f(source)
+        try:
+            # Certain hash functions have a hexdigest() which expects a length parameter
+            pubkey_digest = h.hexdigest()
+        except TypeError:
+            pubkey_digest = h.hexdigest(32)
         fingerprint[algo] = ':'.join(pubkey_digest[i:i + 2] for i in range(0, len(pubkey_digest), 2))
+
+    return fingerprint
+
+
+def get_fingerprint(path, passphrase=None):
+    """Generate the fingerprint of the public key. """
+
+    privatekey = load_privatekey(path, passphrase)
+    try:
+        publickey = crypto.dump_publickey(crypto.FILETYPE_ASN1, privatekey)
+        return get_fingerprint_of_bytes(publickey)
     except AttributeError:
         # If PyOpenSSL < 16.0 crypto.dump_publickey() will fail.
         # By doing this we prevent the code from raising an error
         # yet we return no value in the fingerprint hash.
-        pass
-
-    return fingerprint
+        return None
 
 
 def load_privatekey(path, passphrase=None):

lib/ansible/modules/crypto/openssl_privatekey.py

@@ -16,15 +16,24 @@ ANSIBLE_METADATA = {'metadata_version': '1.1',
 DOCUMENTATION = '''
 ---
 module: openssl_privatekey
-author: "Yanis Guenane (@Spredzy)"
+author:
+    - "Yanis Guenane (@Spredzy)"
+    - "Felix Fontein (@felixfontein)"
 version_added: "2.3"
 short_description: Generate OpenSSL private keys.
 description:
-    - "This module allows one to (re)generate OpenSSL private keys. It uses
-       the pyOpenSSL python library to interact with openssl. One can generate
-       either RSA or DSA private keys. Keys are generated in PEM format."
+    - "This module allows one to (re)generate OpenSSL private keys. One can
+       generate L(RSA,https://en.wikipedia.org/wiki/RSA_(cryptosystem)),
+       L(DSA,https://en.wikipedia.org/wiki/Digital_Signature_Algorithm) or
+       L(ECC,https://en.wikipedia.org/wiki/Elliptic-curve_cryptography)
+       private keys. Keys are generated in PEM format."
+    - "The module can use the cryptography Python library, or the pyOpenSSL Python
+       library. By default, it tries to detect which one is available. This can be
+       overridden with the I(select_crypto_backend) option."
 requirements:
-    - "python-pyOpenSSL"
+    - "One of the following Python libraries:"
+    - "cryptography >= 1.2.3 (older versions might work as well)"
+    - "pyOpenSSL"
 options:
     state:
         required: false
@@ -40,9 +49,43 @@ options:
     type:
         required: false
         default: "RSA"
-        choices: [ RSA, DSA ]
+        choices:
+            - RSA
+            - DSA
+            - ECC
+            # - X448
+            # - X25519
         description:
             - The algorithm used to generate the TLS/SSL private key
+            - "Note that C(ECC) requires the C(cryptography) backend. Depending on the curve, you need a newer
+               version of the cryptography backend."
+    curve:
+        required: false
+        choices:
+            - secp384r1
+            - secp521r1
+            - secp224r1
+            - secp192r1
+            - secp256k1
+            - brainpoolP256r1
+            - brainpoolP384r1
+            - brainpoolP512r1
+            - sect571k1
+            - sect409k1
+            - sect283k1
+            - sect233k1
+            - sect163k1
+            - sect571r1
+            - sect409r1
+            - sect283r1
+            - sect233r1
+            - sect163r2
+        description:
+            - Note that not all curves are supported by all versions of C(cryptography).
+            - For maximal interoperability, C(secp384r1) or C(secp256k1) should be used.
+            - We use the curve names as defined in the
+              L(IANA registry for TLS,https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8).
+        version_added: "2.8"
     force:
         required: false
         default: False
@@ -62,7 +105,24 @@ options:
         required: false
         description:
             - The cipher to encrypt the private key. (cipher can be found by running `openssl list-cipher-algorithms`)
+            - When using the C(cryptography) backend, use C(auto).
         version_added: "2.4"
+    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"
 extends_documentation_fragment: files
 '''
 
@@ -105,14 +165,20 @@ type:
     returned: changed or success
     type: string
     sample: RSA
+curve:
+    description: Elliptic curve used to generate the TLS/SSL private key
+    returned: changed or success, and I(type) is C(ECC)
+    type: string
+    sample: secp256k1
 filename:
     description: Path to the generated TLS/SSL private key file
     returned: changed or success
     type: string
     sample: /etc/ssl/private/ansible.com.pem
 fingerprint:
-    description: The fingerprint of the public key. Fingerprint will be generated for each hashlib.algorithms available.
-                 Requires PyOpenSSL >= 16.0 for meaningful output.
+    description: The fingerprint of the public key. Fingerprint will be generated for
+                 each C(hashlib.algorithms) available.
+                 The PyOpenSSL backend requires PyOpenSSL >= 16.0 for meaningful output.
     returned: changed or success
     type: dict
     sample:
@@ -124,15 +190,46 @@ fingerprint:
       sha512: "fd:ed:5e:39:48:5f:9f:fe:7f:25:06:3f:79:08:cd:ee:a5:e7:b3:3d:13:82:87:1f:84:e1:f5:c7:28:77:53:94:86:56:38:69:f0:d9:35:22:01:1e:a6:60:...:0f:9b"
 '''
 
+import abc
 import os
 import traceback
+from distutils.version import LooseVersion
+
+MINIMAL_PYOPENSSL_VERSION = '0.6'
+MINIMAL_CRYPTOGRAPHY_VERSION = '1.2.3'
 
 try:
+    import OpenSSL
     from OpenSSL import crypto
+    PYOPENSSL_VERSION = LooseVersion(OpenSSL.__version__)
+except ImportError:
+    PYOPENSSL_FOUND = False
+else:
+    PYOPENSSL_FOUND = True
+try:
+    import cryptography
+    import cryptography.exceptions
+    import cryptography.hazmat.backends
+    import cryptography.hazmat.primitives.serialization
+    import cryptography.hazmat.primitives.asymmetric.rsa
+    import cryptography.hazmat.primitives.asymmetric.dsa
+    import cryptography.hazmat.primitives.asymmetric.ec
+    import cryptography.hazmat.primitives.asymmetric.utils
+    CRYPTOGRAPHY_VERSION = LooseVersion(cryptography.__version__)
 except ImportError:
-    pyopenssl_found = False
+    CRYPTOGRAPHY_FOUND = False
 else:
-    pyopenssl_found = True
+    CRYPTOGRAPHY_FOUND = True
+    try:
+        import cryptography.hazmat.primitives.asymmetric.x25519
+        CRYPTOGRAPHY_HAS_X25519 = True
+    except ImportError:
+        CRYPTOGRAPHY_HAS_X25519 = False
+    try:
+        import cryptography.hazmat.primitives.asymmetric.x448
+        CRYPTOGRAPHY_HAS_X448 = True
+    except ImportError:
+        CRYPTOGRAPHY_HAS_X448 = False
 
 from ansible.module_utils import crypto as crypto_utils
 from ansible.module_utils._text import to_native, to_bytes
@@ -144,10 +241,10 @@ class PrivateKeyError(crypto_utils.OpenSSLObjectError):
     pass
 
 
-class PrivateKey(crypto_utils.OpenSSLObject):
+class PrivateKeyBase(crypto_utils.OpenSSLObject):
 
     def __init__(self, module):
-        super(PrivateKey, self).__init__(
+        super(PrivateKeyBase, self).__init__(
             module.params['path'],
             module.params['state'],
             module.params['force'],
@@ -163,21 +260,19 @@ class PrivateKey(crypto_utils.OpenSSLObject):
         if self.mode is None:
             self.mode = 0o600
 
-        self.type = crypto.TYPE_RSA
-        if module.params['type'] == 'DSA':
-            self.type = crypto.TYPE_DSA
+    @abc.abstractmethod
+    def _generate_private_key_data(self):
+        pass
+
+    @abc.abstractmethod
+    def _get_fingerprint(self):
+        pass
 
     def generate(self, module):
         """Generate a keypair."""
 
         if not self.check(module, perms_required=False) or self.force:
-            self.privatekey = crypto.PKey()
-
-            try:
-                self.privatekey.generate_key(self.type, self.size)
-            except (TypeError, ValueError) as exc:
-                raise PrivateKeyError(exc)
-
+            privatekey_data = self._generate_private_key_data()
             try:
                 privatekey_file = os.open(self.path, os.O_WRONLY | os.O_CREAT | os.O_TRUNC)
                 os.close(privatekey_file)
@@ -192,42 +287,92 @@ class PrivateKey(crypto_utils.OpenSSLObject):
                             module.fail_json(msg="%s" % to_native(e), exception=traceback.format_exc())
                 os.chmod(self.path, self.mode)
                 privatekey_file = os.open(self.path, os.O_WRONLY | os.O_CREAT | os.O_TRUNC, self.mode)
-                if self.cipher and self.passphrase:
-                    os.write(privatekey_file, crypto.dump_privatekey(crypto.FILETYPE_PEM, self.privatekey,
-                                                                     self.cipher, to_bytes(self.passphrase)))
-                else:
-                    os.write(privatekey_file, crypto.dump_privatekey(crypto.FILETYPE_PEM, self.privatekey))
+                os.write(privatekey_file, privatekey_data)
                 os.close(privatekey_file)
                 self.changed = True
             except IOError as exc:
                 self.remove()
                 raise PrivateKeyError(exc)
 
-        self.fingerprint = crypto_utils.get_fingerprint(self.path, self.passphrase)
+        self.fingerprint = self._get_fingerprint()
         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 _check_passphrase(self):
+        pass
+
+    @abc.abstractmethod
+    def _check_size_and_type(self):
+        pass
+
     def check(self, module, perms_required=True):
         """Ensure the resource is in its desired state."""
 
-        state_and_perms = super(PrivateKey, self).check(module, perms_required)
+        state_and_perms = super(PrivateKeyBase, self).check(module, perms_required)
 
-        def _check_size(privatekey):
-            return self.size == privatekey.bits()
+        if not state_and_perms or not self._check_passphrase():
+            return False
 
-        def _check_type(privatekey):
-            return self.type == privatekey.type()
+        return self._check_size_and_type()
+
+    def dump(self):
+        """Serialize the object into a dictionary."""
+
+        result = {
+            'size': self.size,
+            'filename': self.path,
+            'changed': self.changed,
+            'fingerprint': self.fingerprint,
+        }
+
+        return result
+
+
+# Implementation with using pyOpenSSL
+class PrivateKeyPyOpenSSL(PrivateKeyBase):
+
+    def __init__(self, module):
+        super(PrivateKeyPyOpenSSL, self).__init__(module)
+
+        if module.params['type'] == 'RSA':
+            self.type = crypto.TYPE_RSA
+        elif module.params['type'] == 'DSA':
+            self.type = crypto.TYPE_DSA
+        else:
+            module.fail_json(msg="PyOpenSSL backend only supports RSA and DSA keys.")
+
+    def _generate_private_key_data(self):
+        self.privatekey = crypto.PKey()
+
+        try:
+            self.privatekey.generate_key(self.type, self.size)
+        except (TypeError, ValueError) as exc:
+            raise PrivateKeyError(exc)
+
+        if self.cipher and self.passphrase:
+            return crypto.dump_privatekey(crypto.FILETYPE_PEM, self.privatekey,
+                                          self.cipher, to_bytes(self.passphrase))
+        else:
+            return crypto.dump_privatekey(crypto.FILETYPE_PEM, self.privatekey)
 
-        def _check_passphrase():
+    def _get_fingerprint(self):
+        return crypto_utils.get_fingerprint(self.path, self.passphrase)
+
+    def _check_passphrase(self):
         try:
             crypto_utils.load_privatekey(self.path, self.passphrase)
             return True
         except crypto.Error:
             return False
 
-        if not state_and_perms or not _check_passphrase():
-            return False
+    def _check_size_and_type(self):
+        def _check_size(privatekey):
+            return self.size == privatekey.bits()
+
+        def _check_type(privatekey):
+            return self.type == privatekey.type()
 
         privatekey = crypto_utils.load_privatekey(self.path, self.passphrase)
 
@@ -236,12 +381,7 @@ class PrivateKey(crypto_utils.OpenSSLObject):
     def dump(self):
         """Serialize the object into a dictionary."""
 
-        result = {
-            'size': self.size,
-            'filename': self.path,
-            'changed': self.changed,
-            'fingerprint': self.fingerprint,
-        }
+        result = super(PrivateKeyPyOpenSSL, self).dump()
 
         if self.type == crypto.TYPE_RSA:
             result['type'] = 'RSA'
@@ -251,26 +391,197 @@ class PrivateKey(crypto_utils.OpenSSLObject):
         return result
 
 
+# Implementation with using cryptography
+class PrivateKeyCryptography(PrivateKeyBase):
+
+    def _get_ec_class(self, ectype):
+        ecclass = cryptography.hazmat.primitives.asymmetric.ec.__dict__.get(ectype)
+        if ecclass is None:
+            self.module.fail_json(msg='Your cryptography version does not support {0}'.format(ectype))
+        return ecclass
+
+    def _add_curve(self, name, ectype, deprecated=False):
+        def create(size):
+            ecclass = self._get_ec_class(ectype)
+            return ecclass()
+
+        def verify(privatekey):
+            ecclass = self._get_ec_class(ectype)
+            return isinstance(privatekey.private_numbers().public_numbers.curve, ecclass)
+
+        self.curves[name] = {
+            'create': create,
+            'verify': verify,
+            'deprecated': deprecated,
+        }
+
+    def __init__(self, module):
+        super(PrivateKeyCryptography, self).__init__(module)
+
+        self.curves = dict()
+        self._add_curve('secp384r1', 'SECP384R1')
+        self._add_curve('secp521r1', 'SECP521R1')
+        self._add_curve('secp224r1', 'SECP224R1')
+        self._add_curve('secp192r1', 'SECP192R1')
+        self._add_curve('secp256k1', 'SECP256K1')
+        self._add_curve('brainpoolP256r1', 'BrainpoolP256R1', deprecated=True)
+        self._add_curve('brainpoolP384r1', 'BrainpoolP384R1', deprecated=True)
+        self._add_curve('brainpoolP512r1', 'BrainpoolP512R1', deprecated=True)
+        self._add_curve('sect571k1', 'SECT571K1', deprecated=True)
+        self._add_curve('sect409k1', 'SECT409K1', deprecated=True)
+        self._add_curve('sect283k1', 'SECT283K1', deprecated=True)
+        self._add_curve('sect233k1', 'SECT233K1', deprecated=True)
+        self._add_curve('sect163k1', 'SECT163K1', deprecated=True)
+        self._add_curve('sect571r1', 'SECT571R1', deprecated=True)
+        self._add_curve('sect409r1', 'SECT409R1', deprecated=True)
+        self._add_curve('sect283r1', 'SECT283R1', deprecated=True)
+        self._add_curve('sect233r1', 'SECT233R1', deprecated=True)
+        self._add_curve('sect163r2', 'SECT163R2', deprecated=True)
+
+        self.module = module
+        self.cryptography_backend = cryptography.hazmat.backends.default_backend()
+
+        self.type = module.params['type']
+        self.curve = module.params['curve']
+        if not CRYPTOGRAPHY_HAS_X25519 and self.type == 'X25519':
+            self.module.fail_json(msg='Your cryptography version does not support X25519')
+        if not CRYPTOGRAPHY_HAS_X448 and self.type == 'X448':
+            self.module.fail_json(msg='Your cryptography version does not support X448')
+
+    def _generate_private_key_data(self):
+        try:
+            if self.type == 'RSA':
+                self.privatekey = cryptography.hazmat.primitives.asymmetric.rsa.generate_private_key(
+                    public_exponent=65537,  # OpenSSL always uses this
+                    key_size=self.size,
+                    backend=self.cryptography_backend
+                )
+            if self.type == 'DSA':
+                self.privatekey = cryptography.hazmat.primitives.asymmetric.dsa.generate_private_key(
+                    key_size=self.size,
+                    backend=self.cryptography_backend
+                )
+            if CRYPTOGRAPHY_HAS_X25519 and self.type == 'X25519':
+                self.privatekey = cryptography.hazmat.primitives.asymmetric.x25519.X25519PrivateKey.generate()
+            if CRYPTOGRAPHY_HAS_X448 and self.type == 'X448':
+                self.privatekey = cryptography.hazmat.primitives.asymmetric.x448.X448PrivateKey.generate()
+            if self.type == 'ECC' and self.curve in self.curves:
+                if self.curves[self.curve]['deprecated']:
+                    self.module.warn('Elliptic curves of type {0} should not be used for new keys!'.format(self.curve))
+                self.privatekey = cryptography.hazmat.primitives.asymmetric.ec.generate_private_key(
+                    curve=self.curves[self.curve]['create'](self.size),
+                    backend=self.cryptography_backend
+                )
+        except cryptography.exceptions.UnsupportedAlgorithm as e:
+            self.module.fail_json(msg='Cryptography backend does not support the algorithm required for {0}'.format(self.type))
+
+        # Select key encryption
+        encryption_algorithm = cryptography.hazmat.primitives.serialization.NoEncryption()
+        if self.cipher and self.passphrase:
+            if self.cipher == 'auto':
+                encryption_algorithm = cryptography.hazmat.primitives.serialization.BestAvailableEncryption(to_bytes(self.passphrase))
+            else:
+                self.module.fail_json(msg='Cryptography backend can only use "auto" for cipher option.')
+
+        # Serialize key
+        return self.privatekey.private_bytes(
+            encoding=cryptography.hazmat.primitives.serialization.Encoding.PEM,
+            format=cryptography.hazmat.primitives.serialization.PrivateFormat.TraditionalOpenSSL,
+            encryption_algorithm=encryption_algorithm
+        )
+
+    def _load_privatekey(self):
+        try:
+            with open(self.path, 'rb') as f:
+                return cryptography.hazmat.primitives.serialization.load_pem_private_key(
+                    f.read(),
+                    None if self.passphrase is None else to_bytes(self.passphrase),
+                    backend=self.cryptography_backend
+                )
+        except Exception as e:
+            raise PrivateKeyError(e)
+
+    def _get_fingerprint(self):
+        # Get bytes of public key
+        private_key = self._load_privatekey()
+        public_key = private_key.public_key()
+        public_key_bytes = public_key.public_bytes(
+            cryptography.hazmat.primitives.serialization.Encoding.DER,
+            cryptography.hazmat.primitives.serialization.PublicFormat.SubjectPublicKeyInfo
+        )
+        # Get fingerprints of public_key_bytes
+        return crypto_utils.get_fingerprint_of_bytes(public_key_bytes)
+
+    def _check_passphrase(self):
+        try:
+            self._load_privatekey()
+            return True
+        except crypto.Error:
+            return False
+
+    def _check_size_and_type(self):
+        privatekey = self._load_privatekey()
+
+        if isinstance(privatekey, cryptography.hazmat.primitives.asymmetric.rsa.RSAPrivateKey):
+            return self.type == 'RSA' and self.size == privatekey.key_size
+        if isinstance(privatekey, cryptography.hazmat.primitives.asymmetric.dsa.DSAPrivateKey):
+            return self.type == 'DSA' and self.size == privatekey.key_size
+        if CRYPTOGRAPHY_HAS_X25519 and isinstance(privatekey, cryptography.hazmat.primitives.asymmetric.x25519.X25519PrivateKey):
+            return self.type == 'X25519'
+        if CRYPTOGRAPHY_HAS_X448 and isinstance(privatekey, cryptography.hazmat.primitives.asymmetric.x448.X448PrivateKey):
+            return self.type == 'X448'
+        if isinstance(privatekey, cryptography.hazmat.primitives.asymmetric.ec.EllipticCurvePrivateKey):
+            if self.type != 'ECC':
+                return False
+            if self.curve not in self.curves:
+                return False
+            return self.curves[self.curve]['verify'](privatekey)
+
+        return False
+
+    def dump(self):
+        """Serialize the object into a dictionary."""
+        result = super(PrivateKeyCryptography, self).dump()
+        result['type'] = self.type
+        if self.type == 'ECC':
+            result['curve'] = self.curve
+        return result
+
+
 def main():
 
     module = AnsibleModule(
         argument_spec=dict(
             state=dict(default='present', choices=['present', 'absent'], type='str'),
             size=dict(default=4096, type='int'),
-            type=dict(default='RSA', choices=['RSA', 'DSA'], type='str'),
+            type=dict(default='RSA', choices=[
+                'RSA', 'DSA', 'ECC',
+                # x25519 is missing serialization functions: https://github.com/pyca/cryptography/issues/4386
+                # x448 is also missing it: https://github.com/pyca/cryptography/pull/4580#issuecomment-437913340
+                # 'X448', 'X25519',
+            ], type='str'),
+            curve=dict(choices=[
+                'secp384r1', 'secp521r1', 'secp224r1', 'secp192r1', 'secp256k1',
+                'brainpoolP256r1', 'brainpoolP384r1', 'brainpoolP512r1',
+                'sect571k1', 'sect409k1', 'sect283k1', 'sect233k1', 'sect163k1',
+                'sect571r1', 'sect409r1', 'sect283r1', 'sect233r1', 'sect163r2',
+            ], type='str'),
             force=dict(default=False, type='bool'),
             path=dict(required=True, type='path'),
             passphrase=dict(type='str', no_log=True),
             cipher=dict(type='str'),
+            select_crypto_backend=dict(required=False, choices=['auto', 'pyopenssl', 'cryptography'], default='auto', type='str'),
         ),
         supports_check_mode=True,
         add_file_common_args=True,
-        required_together=[['cipher', 'passphrase']],
+        required_together=[
+            ['cipher', 'passphrase']
+        ],
+        required_if=[
+            ['type', 'ECC', ['curve']],
+        ],
     )
 
-    if not pyopenssl_found:
-        module.fail_json(msg='the python pyOpenSSL module is required')
-
     base_dir = os.path.dirname(module.params['path'])
     if not os.path.isdir(base_dir):
         module.fail_json(
@@ -278,7 +589,40 @@ def main():
             msg='The directory %s does not exist or the file is not a directory' % base_dir
         )
 
-    private_key = PrivateKey(module)
+    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)
+
+        # Decision
+        if module.params['cipher'] and module.params['passphrase'] and module.params['cipher'] != 'auto':
+            # First try pyOpenSSL, then cryptography
+            if can_use_pyopenssl:
+                backend = 'pyopenssl'
+            elif can_use_cryptography:
+                backend = 'cryptography'
+        else:
+            # 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 detect none of the Python libraries '
+                                  'cryptography (>= {0}) and pyOpenSSL (>= {1})').format(
+                                      MINIMAL_CRYPTOGRAPHY_VERSION,
+                                      MINIMAL_PYOPENSSL_VERSION))
+    if backend == 'pyopenssl':
+        if not PYOPENSSL_FOUND:
+            module.fail_json(msg='The Python pyOpenSSL library is required')
+        private_key = PrivateKeyPyOpenSSL(module)
+    elif backend == 'cryptography':
+        if not CRYPTOGRAPHY_FOUND:
+            module.fail_json(msg='The Python cryptography library is required')
+        private_key = PrivateKeyCryptography(module)
 
     if private_key.state == 'present':
 

test/integration/targets/openssl_privatekey/tasks/impl.yml

@@ -0,0 +1,144 @@
+---
+- name: Generate privatekey1 - standard
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey1.pem'
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- name: Generate privatekey2 - size 2048
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey2.pem'
+    size: 2048
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- name: Generate privatekey3 - type DSA
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey3.pem'
+    type: DSA
+    size: 3072
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- name: Generate privatekey4 - standard
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey4.pem'
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- name: Delete privatekey4 - standard
+  openssl_privatekey:
+    state: absent
+    path: '{{ output_dir }}/privatekey4.pem'
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- name: Generate privatekey5 - standard - with passphrase
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey5.pem'
+    passphrase: ansible
+    cipher: "{{ 'aes256' if select_crypto_backend == 'pyopenssl' else 'auto' }}"
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- name: Generate privatekey5 - standard - idempotence
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey5.pem'
+    passphrase: ansible
+    cipher: "{{ 'aes256' if select_crypto_backend == 'pyopenssl' else 'auto' }}"
+    select_crypto_backend: '{{ select_crypto_backend }}'
+  register: privatekey5_idempotence
+
+- name: Generate privatekey6 - standard - with non-ASCII passphrase
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey6.pem'
+    passphrase: ànsïblé
+    cipher: "{{ 'aes256' if select_crypto_backend == 'pyopenssl' else 'auto' }}"
+    select_crypto_backend: '{{ select_crypto_backend }}'
+
+- set_fact:
+    ecc_types: []
+  when: select_crypto_backend == 'pyopenssl'
+- set_fact:
+    ecc_types:
+    # - curve: X448
+    #   min_cryptography_version: "2.5"
+    # - curve: X25519
+    #   min_cryptography_version: "2.0"
+    - curve: secp384r1
+      openssl_name: secp384r1
+      min_cryptography_version: "0.5"
+    - curve: secp521r1
+      openssl_name: secp521r1
+      min_cryptography_version: "0.5"
+    - curve: secp224r1
+      openssl_name: secp224r1
+      min_cryptography_version: "0.5"
+    - curve: secp192r1
+      openssl_name: prime192v1
+      min_cryptography_version: "0.5"
+    - curve: secp256k1
+      openssl_name: secp256k1
+      min_cryptography_version: "0.9"
+    - curve: brainpoolP256r1
+      openssl_name: brainpoolP256r1
+      min_cryptography_version: "2.2"
+    - curve: brainpoolP384r1
+      openssl_name: brainpoolP384r1
+      min_cryptography_version: "2.2"
+    - curve: brainpoolP512r1
+      openssl_name: brainpoolP512r1
+      min_cryptography_version: "2.2"
+    - curve: sect571k1
+      openssl_name: sect571k1
+      min_cryptography_version: "0.5"
+    - curve: sect409k1
+      openssl_name: sect409k1
+      min_cryptography_version: "0.5"
+    - curve: sect283k1
+      openssl_name: sect283k1
+      min_cryptography_version: "0.5"
+    - curve: sect233k1
+      openssl_name: sect233k1
+      min_cryptography_version: "0.5"
+    - curve: sect163k1
+      openssl_name: sect163k1
+      min_cryptography_version: "0.5"
+    - curve: sect571r1
+      openssl_name: sect571r1
+      min_cryptography_version: "0.5"
+    - curve: sect409r1
+      openssl_name: sect409r1
+      min_cryptography_version: "0.5"
+    - curve: sect283r1
+      openssl_name: sect283r1
+      min_cryptography_version: "0.5"
+    - curve: sect233r1
+      openssl_name: sect233r1
+      min_cryptography_version: "0.5"
+    - curve: sect163r2
+      openssl_name: sect163r2
+      min_cryptography_version: "0.5"
+  when: select_crypto_backend == 'cryptography'
+
+- name: Test ECC key generation
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey-{{ item.curve }}.pem'
+    type: ECC
+    curve: "{{ item.curve }}"
+    select_crypto_backend: '{{ select_crypto_backend }}'
+  when: |
+    cryptography_version.stdout is version(item.min_cryptography_version, '>=') and
+    item.openssl_name in openssl_ecc_list
+  loop: "{{ ecc_types }}"
+  loop_control:
+    label: "{{ item.curve }}"
+  register: privatekey_ecc_generate
+
+- name: Test ECC key generation (idempotency)
+  openssl_privatekey:
+    path: '{{ output_dir }}/privatekey-{{ item.curve }}.pem'
+    type: ECC
+    curve: "{{ item.curve }}"
+    select_crypto_backend: '{{ select_crypto_backend }}'
+  when: |
+    cryptography_version.stdout is version(item.min_cryptography_version, '>=') and
+    item.openssl_name in openssl_ecc_list
+  loop: "{{ ecc_types }}"
+  loop_control:
+    label: "{{ item.curve }}"
+  register: privatekey_ecc_idempotency

test/integration/targets/openssl_privatekey/tasks/main.yml

@@ -1,43 +1,95 @@
-- name: Generate privatekey1 - standard
-  openssl_privatekey:
-    path: '{{ output_dir }}/privatekey1.pem'
+---
+- name: Find out which elliptic curves are supported by installed OpenSSL
+  command: openssl ecparam -list_curves
+  register: openssl_ecc
 
-- name: Generate privatekey2 - size 2048
-  openssl_privatekey:
-    path: '{{ output_dir }}/privatekey2.pem'
-    size: 2048
+- name: Compile list of elliptic curves supported by OpenSSL
+  set_fact:
+    openssl_ecc_list: |
+      {{
+        openssl_ecc.stdout_lines
+        | map('regex_search', '^ *([a-zA-Z0-9_-]+) *: .*$')
+        | select()
+        | map('regex_replace', '^ *([a-zA-Z0-9_-]+) *: .*$', '\1')
+        | list
+      }}
+  when: ansible_distribution != 'CentOS' or ansible_distribution_major_version != '6'
+  # CentOS comes with a very old jinja2 which does not include the map() filter...
+- name: Compile list of elliptic curves supported by OpenSSL (CentOS 6)
+  set_fact:
+    openssl_ecc_list:
+    - secp384r1
+    - secp521r1
+    - prime256v1
+  when: ansible_distribution == 'CentOS' and ansible_distribution_major_version == '6'
 
-- name: Generate privatekey3 - type DSA
-  openssl_privatekey:
-    path: '{{ output_dir }}/privatekey3.pem'
-    type: DSA
+- name: List of elliptic curves supported by OpenSSL
+  debug: var=openssl_ecc_list
 
-- name: Generate privatekey4 - standard
-  openssl_privatekey:
-    path: '{{ output_dir }}/privatekey4.pem'
+- block:
+  - name: Running tests with pyOpenSSL backend
+    include_tasks: impl.yml
+    vars:
+      select_crypto_backend: pyopenssl
 
-- name: Delete privatekey4 - standard
-  openssl_privatekey:
+  - import_tasks: ../tests/validate.yml
+
+  # FIXME: minimal pyOpenSSL version?!
+  when: pyopenssl_version.stdout is version('0.6', '>=')
+
+- name: Remove output directory
+  file:
+    path: "{{ output_dir }}"
     state: absent
-    path: '{{ output_dir }}/privatekey4.pem'
 
-- name: Generate privatekey5 - standard - with passphrase
-  openssl_privatekey:
-    path: '{{ output_dir }}/privatekey5.pem'
-    passphrase: ansible
-    cipher: aes256
+- name: Re-create output directory
+  file:
+    path: "{{ output_dir }}"
+    state: directory
+
+- block:
+  - name: Running tests with cryptography backend
+    include_tasks: impl.yml
+    vars:
+      select_crypto_backend: cryptography
+
+  - import_tasks: ../tests/validate.yml
+
+  when: cryptography_version.stdout is version('0.5', '>=')
 
-- name: Generate privatekey5 - standard - idempotence
+- name: Check that fingerprints do not depend on the backend
+  block:
+  - name: "Fingerprint comparison: pyOpenSSL"
     openssl_privatekey:
-    path: '{{ output_dir }}/privatekey5.pem'
-    passphrase: ansible
-    cipher: aes256
-  register: privatekey5_idempotence
+      path: '{{ output_dir }}/fingerprint-{{ item }}.pem'
+      type: "{{ item }}"
+      size: 1024
+      select_crypto_backend: pyopenssl
+    loop:
+    - RSA
+    - DSA
+    register: fingerprint_pyopenssl
 
-- name: Generate privatekey6 - standard - with non-ASCII passphrase
+  - name: "Fingerprint comparison: cryptography"
     openssl_privatekey:
-    path: '{{ output_dir }}/privatekey6.pem'
-    passphrase: ànsïblé
-    cipher: aes256
+      path: '{{ output_dir }}/fingerprint-{{ item }}.pem'
+      type: "{{ item }}"
+      size: 1024
+      select_crypto_backend: cryptography
+    loop:
+    - RSA
+    - DSA
+    register: fingerprint_cryptography
 
-- import_tasks: ../tests/validate.yml
+  - name: Verify that fingerprints match
+    assert:
+      that: item.0.fingerprint[item.2] == item.1.fingerprint[item.2]
+    when: item.0 is not skipped and item.1 is not skipped
+    loop: |
+      {{ query('nested',
+            fingerprint_pyopenssl.results | zip(fingerprint_cryptography.results),
+            fingerprint_pyopenssl.results[0].fingerprint.keys()
+      ) if fingerprint_pyopenssl.results[0].fingerprint else [] }}
+    loop_control:
+      label: "{{ [item.0.item, item.2] }}"
+  when: pyopenssl_version.stdout is version('0.6', '>=') and cryptography_version.stdout is version('0.5', '>=')

test/integration/targets/openssl_privatekey/tests/validate.yml

@@ -1,3 +1,4 @@
+---
 - name: Validate privatekey1 (test - RSA key with size 4096 bits)
   shell: "openssl rsa -noout -text -in {{ output_dir }}/privatekey1.pem  | grep Private | sed 's/\\(RSA\\s\\)*Private-Key: (\\(.*\\) bit.*)/\\2/'"
   register: privatekey1
@@ -18,14 +19,14 @@
       - privatekey2.stdout == '2048'
 
 
-- name: Validate privatekey3 (test - DSA key with size 4096 bits)
+- name: Validate privatekey3 (test - DSA key with size 3072 bits)
   shell: "openssl dsa -noout -text -in {{ output_dir }}/privatekey3.pem  | grep Private | sed 's/\\(RSA\\s\\)*Private-Key: (\\(.*\\) bit.*)/\\2/'"
   register: privatekey3
 
-- name: Validate privatekey3 (assert - DSA key with size 4096 bits)
+- name: Validate privatekey3 (assert - DSA key with size 3072 bits)
   assert:
     that:
-      - privatekey3.stdout == '4096'
+      - privatekey3.stdout == '3072'
 
 
 - name: Validate privatekey4 (test - Ensure key has been removed)
@@ -68,3 +69,38 @@
     that:
       - privatekey6.stdout == '4096'
   when: openssl_version.stdout is version('0.9.8zh', '>=')
+
+- name: Validate ECC generation (dump with OpenSSL)
+  shell: "openssl ec -in {{ output_dir }}/privatekey-{{ item.item.curve }}.pem -noout -text | grep 'ASN1 OID: ' | sed 's/ASN1 OID: \\([^ ]*\\)/\\1/'"
+  loop: "{{ privatekey_ecc_generate.results }}"
+  register: privatekey_ecc_dump
+  when: openssl_version.stdout is version('0.9.8zh', '>=') and 'skip_reason' not in item
+  loop_control:
+    label: "{{ item.item.curve }}"
+
+- name: Validate ECC generation
+  assert:
+    that:
+    - item is changed
+  loop: "{{ privatekey_ecc_generate.results }}"
+  when: "'skip_reason' not in item"
+  loop_control:
+    label: "{{ item.item.curve }}"
+
+- name: Validate ECC generation (curve type)
+  assert:
+    that:
+    - "'skip_reason' in item or item.item.item.openssl_name == item.stdout"
+  loop: "{{ privatekey_ecc_dump.results }}"
+  when: "'skip_reason' not in item"
+  loop_control:
+    label: "{{ item.item.item }} - {{ item.stdout if 'stdout' in item else '<unsupported>' }}"
+
+- name: Validate ECC generation idempotency
+  assert:
+    that:
+    - item is not changed
+  loop: "{{ privatekey_ecc_idempotency.results }}"
+  when: "'skip_reason' not in item"
+  loop_control:
+    label: "{{ item.item.curve }}"

test/integration/targets/setup_openssl/tasks/main.yml

@@ -1,3 +1,4 @@
+---
 - name: Incluse OS-specific variables
   include_vars: '{{ ansible_os_family }}.yml'
   when: not ansible_os_family == "Darwin"