API refactor

venv/lib/python3.12/site-packages/kafka/sasl/__init__.py

@@ -0,0 +1,34 @@
+from __future__ import absolute_import
+
+import platform
+
+from kafka.sasl.gssapi import SaslMechanismGSSAPI
+from kafka.sasl.msk import SaslMechanismAwsMskIam
+from kafka.sasl.oauth import SaslMechanismOAuth
+from kafka.sasl.plain import SaslMechanismPlain
+from kafka.sasl.scram import SaslMechanismScram
+from kafka.sasl.sspi import SaslMechanismSSPI
+
+
+SASL_MECHANISMS = {}
+
+
+def register_sasl_mechanism(name, klass, overwrite=False):
+    if not overwrite and name in SASL_MECHANISMS:
+        raise ValueError('Sasl mechanism %s already defined!' % name)
+    SASL_MECHANISMS[name] = klass
+
+
+def get_sasl_mechanism(name):
+    return SASL_MECHANISMS[name]
+
+
+register_sasl_mechanism('AWS_MSK_IAM', SaslMechanismAwsMskIam)
+if platform.system() == 'Windows':
+    register_sasl_mechanism('GSSAPI', SaslMechanismSSPI)
+else:
+    register_sasl_mechanism('GSSAPI', SaslMechanismGSSAPI)
+register_sasl_mechanism('OAUTHBEARER', SaslMechanismOAuth)
+register_sasl_mechanism('PLAIN', SaslMechanismPlain)
+register_sasl_mechanism('SCRAM-SHA-256', SaslMechanismScram)
+register_sasl_mechanism('SCRAM-SHA-512', SaslMechanismScram)

venv/lib/python3.12/site-packages/kafka/sasl/abc.py

@@ -0,0 +1,33 @@
+from __future__ import absolute_import
+
+import abc
+
+from kafka.vendor.six import add_metaclass
+
+
+@add_metaclass(abc.ABCMeta)
+class SaslMechanism(object):
+    @abc.abstractmethod
+    def __init__(self, **config):
+        pass
+
+    @abc.abstractmethod
+    def auth_bytes(self):
+        pass
+
+    @abc.abstractmethod
+    def receive(self, auth_bytes):
+        pass
+
+    @abc.abstractmethod
+    def is_done(self):
+        pass
+
+    @abc.abstractmethod
+    def is_authenticated(self):
+        pass
+
+    def auth_details(self):
+        if not self.is_authenticated:
+            raise RuntimeError('Not authenticated yet!')
+        return 'Authenticated via SASL'

venv/lib/python3.12/site-packages/kafka/sasl/gssapi.py

@@ -0,0 +1,96 @@
+from __future__ import absolute_import
+
+import struct
+
+# needed for SASL_GSSAPI authentication:
+try:
+    import gssapi
+    from gssapi.raw.misc import GSSError
+except (ImportError, OSError):
+    #no gssapi available, will disable gssapi mechanism
+    gssapi = None
+    GSSError = None
+
+from kafka.sasl.abc import SaslMechanism
+
+
+class SaslMechanismGSSAPI(SaslMechanism):
+    # Establish security context and negotiate protection level
+    # For reference RFC 2222, section 7.2.1
+
+    SASL_QOP_AUTH = 1
+    SASL_QOP_AUTH_INT = 2
+    SASL_QOP_AUTH_CONF = 4
+
+    def __init__(self, **config):
+        assert gssapi is not None, 'GSSAPI lib not available'
+        if 'sasl_kerberos_name' not in config and 'sasl_kerberos_service_name' not in config:
+            raise ValueError('sasl_kerberos_service_name or sasl_kerberos_name required for GSSAPI sasl configuration')
+        self._is_done = False
+        self._is_authenticated = False
+        self.gssapi_name = None
+        if config.get('sasl_kerberos_name', None) is not None:
+            self.auth_id = str(config['sasl_kerberos_name'])
+            if isinstance(config['sasl_kerberos_name'], gssapi.Name):
+                self.gssapi_name = config['sasl_kerberos_name']
+        else:
+            kerberos_domain_name = config.get('sasl_kerberos_domain_name', '') or config.get('host', '')
+            self.auth_id = config['sasl_kerberos_service_name'] + '@' + kerberos_domain_name
+        if self.gssapi_name is None:
+            self.gssapi_name = gssapi.Name(self.auth_id, name_type=gssapi.NameType.hostbased_service).canonicalize(gssapi.MechType.kerberos)
+        self._client_ctx = gssapi.SecurityContext(name=self.gssapi_name, usage='initiate')
+        self._next_token = self._client_ctx.step(None)
+
+    def auth_bytes(self):
+        # GSSAPI Auth does not have a final broker->client message
+        # so mark is_done after the final auth_bytes are provided
+        # in practice we'll still receive a response when using SaslAuthenticate
+        # but not when using the prior unframed approach.
+        if self._is_authenticated:
+            self._is_done = True
+        return self._next_token or b''
+
+    def receive(self, auth_bytes):
+        if not self._client_ctx.complete:
+            # The server will send a token back. Processing of this token either
+            # establishes a security context, or it needs further token exchange.
+            # The gssapi will be able to identify the needed next step.
+            self._next_token = self._client_ctx.step(auth_bytes)
+        elif self._is_done:
+            # The final step of gssapi is send, so we do not expect any additional bytes
+            # however, allow an empty message to support SaslAuthenticate response
+            if auth_bytes != b'':
+                raise ValueError("Unexpected receive auth_bytes after sasl/gssapi completion")
+        else:
+            # unwraps message containing supported protection levels and msg size
+            msg = self._client_ctx.unwrap(auth_bytes).message
+            # Kafka currently doesn't support integrity or confidentiality security layers, so we
+            # simply set QoP to 'auth' only (first octet). We reuse the max message size proposed
+            # by the server
+            client_flags = self.SASL_QOP_AUTH
+            server_flags = struct.Struct('>b').unpack(msg[0:1])[0]
+            message_parts = [
+                struct.Struct('>b').pack(client_flags & server_flags),
+                msg[1:], # always agree to max message size from server
+                self.auth_id.encode('utf-8'),
+            ]
+            # add authorization identity to the response, and GSS-wrap
+            self._next_token = self._client_ctx.wrap(b''.join(message_parts), False).message
+            # We need to identify the last token in auth_bytes();
+            # we can't rely on client_ctx.complete because it becomes True after generating
+            # the second-to-last token (after calling .step(auth_bytes) for the final time)
+            # We could introduce an additional state variable (i.e., self._final_token),
+            # but instead we just set _is_authenticated. Since the plugin interface does
+            # not read is_authenticated() until after is_done() is True, this should be fine.
+            self._is_authenticated = True
+
+    def is_done(self):
+        return self._is_done
+
+    def is_authenticated(self):
+        return self._is_authenticated
+
+    def auth_details(self):
+        if not self.is_authenticated:
+            raise RuntimeError('Not authenticated yet!')
+        return 'Authenticated as %s to %s via SASL / GSSAPI' % (self._client_ctx.initiator_name, self._client_ctx.target_name)

venv/lib/python3.12/site-packages/kafka/sasl/msk.py

@@ -0,0 +1,244 @@
+from __future__ import absolute_import
+
+import datetime
+import hashlib
+import hmac
+import json
+import logging
+import string
+
+# needed for AWS_MSK_IAM authentication:
+try:
+    from botocore.session import Session as BotoSession
+except ImportError:
+    # no botocore available, will disable AWS_MSK_IAM mechanism
+    BotoSession = None
+
+from kafka.errors import KafkaConfigurationError
+from kafka.sasl.abc import SaslMechanism
+from kafka.vendor.six.moves import urllib
+
+
+log = logging.getLogger(__name__)
+
+
+class SaslMechanismAwsMskIam(SaslMechanism):
+    def __init__(self, **config):
+        assert BotoSession is not None, 'AWS_MSK_IAM requires the "botocore" package'
+        assert config.get('security_protocol', '') == 'SASL_SSL', 'AWS_MSK_IAM requires SASL_SSL'
+        assert 'host' in config, 'AWS_MSK_IAM requires host configuration'
+        self.host = config['host']
+        self._auth = None
+        self._is_done = False
+        self._is_authenticated = False
+
+    def _build_client(self):
+        session = BotoSession()
+        credentials = session.get_credentials().get_frozen_credentials()
+        if not session.get_config_variable('region'):
+            raise KafkaConfigurationError('Unable to determine region for AWS MSK cluster. Is AWS_DEFAULT_REGION set?')
+        return AwsMskIamClient(
+            host=self.host,
+            access_key=credentials.access_key,
+            secret_key=credentials.secret_key,
+            region=session.get_config_variable('region'),
+            token=credentials.token,
+        )
+
+    def auth_bytes(self):
+        client = self._build_client()
+        log.debug("Generating auth token for MSK scope: %s", client._scope)
+        return client.first_message()
+
+    def receive(self, auth_bytes):
+        self._is_done = True
+        self._is_authenticated = auth_bytes != b''
+        self._auth = auth_bytes.decode('utf-8')
+
+    def is_done(self):
+        return self._is_done
+
+    def is_authenticated(self):
+        return self._is_authenticated
+
+    def auth_details(self):
+        if not self.is_authenticated:
+            raise RuntimeError('Not authenticated yet!')
+        return 'Authenticated via SASL / AWS_MSK_IAM %s' % (self._auth,)
+
+
+class AwsMskIamClient:
+    UNRESERVED_CHARS = string.ascii_letters + string.digits + '-._~'
+
+    def __init__(self, host, access_key, secret_key, region, token=None):
+        """
+        Arguments:
+            host (str): The hostname of the broker.
+            access_key (str): An AWS_ACCESS_KEY_ID.
+            secret_key (str): An AWS_SECRET_ACCESS_KEY.
+            region (str): An AWS_REGION.
+            token (Optional[str]): An AWS_SESSION_TOKEN if using temporary
+                credentials.
+        """
+        self.algorithm = 'AWS4-HMAC-SHA256'
+        self.expires = '900'
+        self.hashfunc = hashlib.sha256
+        self.headers = [
+            ('host', host)
+        ]
+        self.version = '2020_10_22'
+
+        self.service = 'kafka-cluster'
+        self.action = '{}:Connect'.format(self.service)
+
+        now = datetime.datetime.utcnow()
+        self.datestamp = now.strftime('%Y%m%d')
+        self.timestamp = now.strftime('%Y%m%dT%H%M%SZ')
+
+        self.host = host
+        self.access_key = access_key
+        self.secret_key = secret_key
+        self.region = region
+        self.token = token
+
+    @property
+    def _credential(self):
+        return '{0.access_key}/{0._scope}'.format(self)
+
+    @property
+    def _scope(self):
+        return '{0.datestamp}/{0.region}/{0.service}/aws4_request'.format(self)
+
+    @property
+    def _signed_headers(self):
+        """
+        Returns (str):
+            An alphabetically sorted, semicolon-delimited list of lowercase
+            request header names.
+        """
+        return ';'.join(sorted(k.lower() for k, _ in self.headers))
+
+    @property
+    def _canonical_headers(self):
+        """
+        Returns (str):
+            A newline-delited list of header names and values.
+            Header names are lowercased.
+        """
+        return '\n'.join(map(':'.join, self.headers)) + '\n'
+
+    @property
+    def _canonical_request(self):
+        """
+        Returns (str):
+            An AWS Signature Version 4 canonical request in the format:
+                <Method>\n
+                <Path>\n
+                <CanonicalQueryString>\n
+                <CanonicalHeaders>\n
+                <SignedHeaders>\n
+                <HashedPayload>
+        """
+        # The hashed_payload is always an empty string for MSK.
+        hashed_payload = self.hashfunc(b'').hexdigest()
+        return '\n'.join((
+            'GET',
+            '/',
+            self._canonical_querystring,
+            self._canonical_headers,
+            self._signed_headers,
+            hashed_payload,
+        ))
+
+    @property
+    def _canonical_querystring(self):
+        """
+        Returns (str):
+            A '&'-separated list of URI-encoded key/value pairs.
+        """
+        params = []
+        params.append(('Action', self.action))
+        params.append(('X-Amz-Algorithm', self.algorithm))
+        params.append(('X-Amz-Credential', self._credential))
+        params.append(('X-Amz-Date', self.timestamp))
+        params.append(('X-Amz-Expires', self.expires))
+        if self.token:
+            params.append(('X-Amz-Security-Token', self.token))
+        params.append(('X-Amz-SignedHeaders', self._signed_headers))
+
+        return '&'.join(self._uriencode(k) + '=' + self._uriencode(v) for k, v in params)
+
+    @property
+    def _signing_key(self):
+        """
+        Returns (bytes):
+            An AWS Signature V4 signing key generated from the secret_key, date,
+            region, service, and request type.
+        """
+        key = self._hmac(('AWS4' + self.secret_key).encode('utf-8'), self.datestamp)
+        key = self._hmac(key, self.region)
+        key = self._hmac(key, self.service)
+        key = self._hmac(key, 'aws4_request')
+        return key
+
+    @property
+    def _signing_str(self):
+        """
+        Returns (str):
+            A string used to sign the AWS Signature V4 payload in the format:
+                <Algorithm>\n
+                <Timestamp>\n
+                <Scope>\n
+                <CanonicalRequestHash>
+        """
+        canonical_request_hash = self.hashfunc(self._canonical_request.encode('utf-8')).hexdigest()
+        return '\n'.join((self.algorithm, self.timestamp, self._scope, canonical_request_hash))
+
+    def _uriencode(self, msg):
+        """
+        Arguments:
+            msg (str): A string to URI-encode.
+
+        Returns (str):
+            The URI-encoded version of the provided msg, following the encoding
+            rules specified: https://github.com/aws/aws-msk-iam-auth#uriencode
+        """
+        return urllib.parse.quote(msg, safe=self.UNRESERVED_CHARS)
+
+    def _hmac(self, key, msg):
+        """
+        Arguments:
+            key (bytes): A key to use for the HMAC digest.
+            msg (str): A value to include in the HMAC digest.
+        Returns (bytes):
+            An HMAC digest of the given key and msg.
+        """
+        return hmac.new(key, msg.encode('utf-8'), digestmod=self.hashfunc).digest()
+
+    def first_message(self):
+        """
+        Returns (bytes):
+            An encoded JSON authentication payload that can be sent to the
+            broker.
+        """
+        signature = hmac.new(
+            self._signing_key,
+            self._signing_str.encode('utf-8'),
+            digestmod=self.hashfunc,
+        ).hexdigest()
+        msg = {
+            'version':  self.version,
+            'host': self.host,
+            'user-agent': 'kafka-python',
+            'action': self.action,
+            'x-amz-algorithm': self.algorithm,
+            'x-amz-credential': self._credential,
+            'x-amz-date': self.timestamp,
+            'x-amz-signedheaders': self._signed_headers,
+            'x-amz-expires': self.expires,
+            'x-amz-signature': signature,
+        }
+        if self.token:
+            msg['x-amz-security-token'] = self.token
+
+        return json.dumps(msg, separators=(',', ':')).encode('utf-8')

venv/lib/python3.12/site-packages/kafka/sasl/oauth.py

@@ -0,0 +1,100 @@
+from __future__ import absolute_import
+
+import abc
+import logging
+
+from kafka.sasl.abc import SaslMechanism
+
+
+log = logging.getLogger(__name__)
+
+
+class SaslMechanismOAuth(SaslMechanism):
+
+    def __init__(self, **config):
+        assert 'sasl_oauth_token_provider' in config, 'sasl_oauth_token_provider required for OAUTHBEARER sasl'
+        assert isinstance(config['sasl_oauth_token_provider'], AbstractTokenProvider), \
+            'sasl_oauth_token_provider must implement kafka.sasl.oauth.AbstractTokenProvider'
+        self.token_provider = config['sasl_oauth_token_provider']
+        self._error = None
+        self._is_done = False
+        self._is_authenticated = False
+
+    def auth_bytes(self):
+        if self._error:
+            # Server should respond to this with SaslAuthenticate failure, which ends the auth process
+            return self._error
+        token = self.token_provider.token()
+        extensions = self._token_extensions()
+        return "n,,\x01auth=Bearer {}{}\x01\x01".format(token, extensions).encode('utf-8')
+
+    def receive(self, auth_bytes):
+        if auth_bytes != b'':
+            error = auth_bytes.decode('utf-8')
+            log.debug("Sending x01 response to server after receiving SASL OAuth error: %s", error)
+            self._error = b'\x01'
+        else:
+            self._is_done = True
+            self._is_authenticated = True
+
+    def is_done(self):
+        return self._is_done
+
+    def is_authenticated(self):
+        return self._is_authenticated
+
+    def _token_extensions(self):
+        """
+        Return a string representation of the OPTIONAL key-value pairs that can be sent with an OAUTHBEARER
+        initial request.
+        """
+        # Builds up a string separated by \x01 via a dict of key value pairs
+        extensions = self.token_provider.extensions()
+        msg = '\x01'.join(['{}={}'.format(k, v) for k, v in extensions.items()])
+        return '\x01' + msg if msg else ''
+
+    def auth_details(self):
+        if not self.is_authenticated:
+            raise RuntimeError('Not authenticated yet!')
+        return 'Authenticated via SASL / OAuth'
+
+# This statement is compatible with both Python 2.7 & 3+
+ABC = abc.ABCMeta('ABC', (object,), {'__slots__': ()})
+
+class AbstractTokenProvider(ABC):
+    """
+    A Token Provider must be used for the SASL OAuthBearer protocol.
+
+    The implementation should ensure token reuse so that multiple
+    calls at connect time do not create multiple tokens. The implementation
+    should also periodically refresh the token in order to guarantee
+    that each call returns an unexpired token. A timeout error should
+    be returned after a short period of inactivity so that the
+    broker can log debugging info and retry.
+
+    Token Providers MUST implement the token() method
+    """
+
+    def __init__(self, **config):
+        pass
+
+    @abc.abstractmethod
+    def token(self):
+        """
+        Returns a (str) ID/Access Token to be sent to the Kafka
+        client.
+        """
+        pass
+
+    def extensions(self):
+        """
+        This is an OPTIONAL method that may be implemented.
+
+        Returns a map of key-value pairs that can
+        be sent with the SASL/OAUTHBEARER initial client request. If
+        not implemented, the values are ignored. This feature is only available
+        in Kafka >= 2.1.0.
+
+        All returned keys and values should be type str
+        """
+        return {}

venv/lib/python3.12/site-packages/kafka/sasl/plain.py

@@ -0,0 +1,41 @@
+from __future__ import absolute_import
+
+import logging
+
+from kafka.sasl.abc import SaslMechanism
+
+
+log = logging.getLogger(__name__)
+
+
+class SaslMechanismPlain(SaslMechanism):
+
+    def __init__(self, **config):
+        if config.get('security_protocol', '') == 'SASL_PLAINTEXT':
+            log.warning('Sending username and password in the clear')
+        assert 'sasl_plain_username' in config, 'sasl_plain_username required for PLAIN sasl'
+        assert 'sasl_plain_password' in config, 'sasl_plain_password required for PLAIN sasl'
+
+        self.username = config['sasl_plain_username']
+        self.password = config['sasl_plain_password']
+        self._is_done = False
+        self._is_authenticated = False
+
+    def auth_bytes(self):
+        # Send PLAIN credentials per RFC-4616
+        return bytes('\0'.join([self.username, self.username, self.password]).encode('utf-8'))
+
+    def receive(self, auth_bytes):
+        self._is_done = True
+        self._is_authenticated = auth_bytes == b''
+
+    def is_done(self):
+        return self._is_done
+
+    def is_authenticated(self):
+        return self._is_authenticated
+
+    def auth_details(self):
+        if not self.is_authenticated:
+            raise RuntimeError('Not authenticated yet!')
+        return 'Authenticated as %s via SASL / Plain' % self.username

venv/lib/python3.12/site-packages/kafka/sasl/scram.py

@@ -0,0 +1,133 @@
+from __future__ import absolute_import
+
+import base64
+import hashlib
+import hmac
+import logging
+import uuid
+
+
+from kafka.sasl.abc import SaslMechanism
+from kafka.vendor import six
+
+
+log = logging.getLogger(__name__)
+
+
+if six.PY2:
+    def xor_bytes(left, right):
+        return bytearray(ord(lb) ^ ord(rb) for lb, rb in zip(left, right))
+else:
+    def xor_bytes(left, right):
+        return bytes(lb ^ rb for lb, rb in zip(left, right))
+
+
+class SaslMechanismScram(SaslMechanism):
+    def __init__(self, **config):
+        assert 'sasl_plain_username' in config, 'sasl_plain_username required for SCRAM sasl'
+        assert 'sasl_plain_password' in config, 'sasl_plain_password required for SCRAM sasl'
+        assert config.get('sasl_mechanism', '') in ScramClient.MECHANISMS, 'Unrecognized SCRAM mechanism'
+        if config.get('security_protocol', '') == 'SASL_PLAINTEXT':
+            log.warning('Exchanging credentials in the clear during Sasl Authentication')
+
+        self.username = config['sasl_plain_username']
+        self.mechanism = config['sasl_mechanism']
+        self._scram_client = ScramClient(
+            config['sasl_plain_username'],
+            config['sasl_plain_password'],
+            config['sasl_mechanism']
+        )
+        self._state = 0
+
+    def auth_bytes(self):
+        if self._state == 0:
+            return self._scram_client.first_message()
+        elif self._state == 1:
+            return self._scram_client.final_message()
+        else:
+            raise ValueError('No auth_bytes for state: %s' % self._state)
+
+    def receive(self, auth_bytes):
+        if self._state == 0:
+            self._scram_client.process_server_first_message(auth_bytes)
+        elif self._state == 1:
+            self._scram_client.process_server_final_message(auth_bytes)
+        else:
+            raise ValueError('Cannot receive bytes in state: %s' % self._state)
+        self._state += 1
+        return self.is_done()
+
+    def is_done(self):
+        return self._state == 2
+
+    def is_authenticated(self):
+        # receive raises if authentication fails...?
+        return self._state == 2
+
+    def auth_details(self):
+        if not self.is_authenticated:
+            raise RuntimeError('Not authenticated yet!')
+        return 'Authenticated as %s via SASL / %s' % (self.username, self.mechanism)
+
+
+class ScramClient:
+    MECHANISMS = {
+        'SCRAM-SHA-256': hashlib.sha256,
+        'SCRAM-SHA-512': hashlib.sha512
+    }
+
+    def __init__(self, user, password, mechanism):
+        self.nonce = str(uuid.uuid4()).replace('-', '').encode('utf-8')
+        self.auth_message = b''
+        self.salted_password = None
+        self.user = user.encode('utf-8')
+        self.password = password.encode('utf-8')
+        self.hashfunc = self.MECHANISMS[mechanism]
+        self.hashname = ''.join(mechanism.lower().split('-')[1:3])
+        self.stored_key = None
+        self.client_key = None
+        self.client_signature = None
+        self.client_proof = None
+        self.server_key = None
+        self.server_signature = None
+
+    def first_message(self):
+        client_first_bare = b'n=' + self.user + b',r=' + self.nonce
+        self.auth_message += client_first_bare
+        return b'n,,' + client_first_bare
+
+    def process_server_first_message(self, server_first_message):
+        self.auth_message += b',' + server_first_message
+        params = dict(pair.split('=', 1) for pair in server_first_message.decode('utf-8').split(','))
+        server_nonce = params['r'].encode('utf-8')
+        if not server_nonce.startswith(self.nonce):
+            raise ValueError("Server nonce, did not start with client nonce!")
+        self.nonce = server_nonce
+        self.auth_message += b',c=biws,r=' + self.nonce
+
+        salt = base64.b64decode(params['s'].encode('utf-8'))
+        iterations = int(params['i'])
+        self.create_salted_password(salt, iterations)
+
+        self.client_key = self.hmac(self.salted_password, b'Client Key')
+        self.stored_key = self.hashfunc(self.client_key).digest()
+        self.client_signature = self.hmac(self.stored_key, self.auth_message)
+        self.client_proof = xor_bytes(self.client_key, self.client_signature)
+        self.server_key = self.hmac(self.salted_password, b'Server Key')
+        self.server_signature = self.hmac(self.server_key, self.auth_message)
+
+    def hmac(self, key, msg):
+        return hmac.new(key, msg, digestmod=self.hashfunc).digest()
+
+    def create_salted_password(self, salt, iterations):
+        self.salted_password = hashlib.pbkdf2_hmac(
+            self.hashname, self.password, salt, iterations
+        )
+
+    def final_message(self):
+        return b'c=biws,r=' + self.nonce + b',p=' + base64.b64encode(self.client_proof)
+
+    def process_server_final_message(self, server_final_message):
+        params = dict(pair.split('=', 1) for pair in server_final_message.decode('utf-8').split(','))
+        if self.server_signature != base64.b64decode(params['v'].encode('utf-8')):
+            raise ValueError("Server sent wrong signature!")

venv/lib/python3.12/site-packages/kafka/sasl/sspi.py

@@ -0,0 +1,111 @@
+from __future__ import absolute_import
+
+import logging
+
+# Windows-only
+try:
+    import sspi
+    import pywintypes
+    import sspicon
+    import win32security
+except ImportError:
+    sspi = None
+
+from kafka.sasl.abc import SaslMechanism
+
+
+log = logging.getLogger(__name__)
+
+
+class SaslMechanismSSPI(SaslMechanism):
+    # Establish security context and negotiate protection level
+    # For reference see RFC 4752, section 3
+
+    SASL_QOP_AUTH = 1
+    SASL_QOP_AUTH_INT = 2
+    SASL_QOP_AUTH_CONF = 4
+
+    def __init__(self, **config):
+        assert sspi is not None, 'No GSSAPI lib available (gssapi or sspi)'
+        if 'sasl_kerberos_name' not in config and 'sasl_kerberos_service_name' not in config:
+            raise ValueError('sasl_kerberos_service_name or sasl_kerberos_name required for GSSAPI sasl configuration')
+        self._is_done = False
+        self._is_authenticated = False
+        if config.get('sasl_kerberos_name', None) is not None:
+            self.auth_id = str(config['sasl_kerberos_name'])
+        else:
+            kerberos_domain_name = config.get('sasl_kerberos_domain_name', '') or config.get('host', '')
+            self.auth_id = config['sasl_kerberos_service_name'] + '/' + kerberos_domain_name
+        scheme = "Kerberos"  # Do not try with Negotiate for SASL authentication. Tokens are different.
+        # https://docs.microsoft.com/en-us/windows/win32/secauthn/context-requirements
+        flags = (
+            sspicon.ISC_REQ_MUTUAL_AUTH |      # mutual authentication
+            sspicon.ISC_REQ_INTEGRITY |        # check for integrity
+            sspicon.ISC_REQ_SEQUENCE_DETECT |  # enable out-of-order messages
+            sspicon.ISC_REQ_CONFIDENTIALITY    # request confidentiality
+        )
+        self._client_ctx = sspi.ClientAuth(scheme, targetspn=self.auth_id, scflags=flags)
+        self._next_token = self._client_ctx.step(None)
+
+    def auth_bytes(self):
+        # GSSAPI Auth does not have a final broker->client message
+        # so mark is_done after the final auth_bytes are provided
+        # in practice we'll still receive a response when using SaslAuthenticate
+        # but not when using the prior unframed approach.
+        if self._client_ctx.authenticated:
+            self._is_done = True
+            self._is_authenticated = True
+        return self._next_token or b''
+
+    def receive(self, auth_bytes):
+        log.debug("Received token from server (size %s)", len(auth_bytes))
+        if not self._client_ctx.authenticated:
+            # calculate an output token from kafka token (or None on first iteration)
+            # https://docs.microsoft.com/en-us/windows/win32/api/sspi/nf-sspi-initializesecuritycontexta
+            # https://docs.microsoft.com/en-us/windows/win32/secauthn/initializesecuritycontext--kerberos
+            # authorize method will wrap for us our token in sspi structures
+            error, auth = self._client_ctx.authorize(auth_bytes)
+            if len(auth) > 0 and len(auth[0].Buffer):
+                log.debug("Got token from context")
+                # this buffer must be sent to the server whatever the result is
+                self._next_token = auth[0].Buffer
+            else:
+                log.debug("Got no token, exchange finished")
+                # seems to be the end of the loop
+                self._next_token = b''
+        elif self._is_done:
+            # The final step of gssapi is send, so we do not expect any additional bytes
+            # however, allow an empty message to support SaslAuthenticate response
+            if auth_bytes != b'':
+                raise ValueError("Unexpected receive auth_bytes after sasl/gssapi completion")
+        else:
+            # Process the security layer negotiation token, sent by the server
+            # once the security context is established.
+
+            # The following part is required by SASL, but not by classic Kerberos.
+            # See RFC 4752
+
+            # unwraps message containing supported protection levels and msg size
+            msg, _was_encrypted = self._client_ctx.unwrap(auth_bytes)
+
+            # Kafka currently doesn't support integrity or confidentiality security layers, so we
+            # simply set QoP to 'auth' only (first octet). We reuse the max message size proposed
+            # by the server
+            client_flags = self.SASL_QOP_AUTH
+            server_flags = msg[0]
+            message_parts = [
+                bytes(client_flags & server_flags),
+                msg[:1],
+                self.auth_id.encode('utf-8'),
+            ]
+            # add authorization identity to the response, and GSS-wrap
+            self._next_token = self._client_ctx.wrap(b''.join(message_parts), False)
+
+    def is_done(self):
+        return self._is_done
+
+    def is_authenticated(self):
+        return self._is_authenticated
+
+    def auth_details(self):
+        return 'Authenticated as %s to %s via SASL / SSPI/GSSAPI \\o/' % (self._client_ctx.initiator_name, self._client_ctx.service_name)