Support AWS_MSK_IAM authentication

kafka/sasl/__init__.py

@@ -1,6 +1,7 @@
 from __future__ import absolute_import
 
 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
@@ -24,3 +25,4 @@ def get_sasl_mechanism(name):
 register_sasl_mechanism('PLAIN', SaslMechanismPlain)
 register_sasl_mechanism('SCRAM-SHA-256', SaslMechanismScram)
 register_sasl_mechanism('SCRAM-SHA-512', SaslMechanismScram)
+register_sasl_mechanism('AWS_MSK_IAM', SaslMechanismAwsMskIam)

kafka/sasl/msk.py

@@ -0,0 +1,233 @@
+from __future__ import absolute_import
+
+import datetime
+import hashlib
+import hmac
+import json
+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.sasl.abc import SaslMechanism
+from kafka.vendor.six.moves import urllib
+
+
+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 auth_bytes(self):
+        session = BotoSession()
+        credentials = session.get_credentials().get_frozen_credentials()
+        client = AwsMskIamClient(
+            host=self.host,
+            access_key=credentials.access_key,
+            secret_key=credentials.secret_key,
+            region=session.get_config_variable('region'),
+            token=credentials.token,
+        )
+        return client.first_message()
+
+    def receive(self, auth_bytes):
+        self._is_done = True
+        self._is_authenticated = auth_bytes != b''
+        self._auth = auth_bytes.deode('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')

test/sasl/test_msk.py

@@ -0,0 +1,67 @@
+import datetime
+import json
+
+from kafka.sasl.msk import AwsMskIamClient
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+
+def client_factory(token=None):
+    now = datetime.datetime.utcfromtimestamp(1629321911)
+    with mock.patch('kafka.sasl.msk.datetime') as mock_dt:
+        mock_dt.datetime.utcnow = mock.Mock(return_value=now)
+        return AwsMskIamClient(
+            host='localhost',
+            access_key='XXXXXXXXXXXXXXXXXXXX',
+            secret_key='XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
+            region='us-east-1',
+            token=token,
+        )
+
+
+def test_aws_msk_iam_client_permanent_credentials():
+    client = client_factory(token=None)
+    msg = client.first_message()
+    assert msg
+    assert isinstance(msg, bytes)
+    actual = json.loads(msg)
+
+    expected = {
+        'version': '2020_10_22',
+        'host': 'localhost',
+        'user-agent': 'kafka-python',
+        'action': 'kafka-cluster:Connect',
+        'x-amz-algorithm': 'AWS4-HMAC-SHA256',
+        'x-amz-credential': 'XXXXXXXXXXXXXXXXXXXX/20210818/us-east-1/kafka-cluster/aws4_request',
+        'x-amz-date': '20210818T212511Z',
+        'x-amz-signedheaders': 'host',
+        'x-amz-expires': '900',
+        'x-amz-signature': '0fa42ae3d5693777942a7a4028b564f0b372bafa2f71c1a19ad60680e6cb994b',
+    }
+    assert actual == expected
+
+
+def test_aws_msk_iam_client_temporary_credentials():
+    client = client_factory(token='XXXXX')
+    msg = client.first_message()
+    assert msg
+    assert isinstance(msg, bytes)
+    actual = json.loads(msg)
+
+    expected = {
+        'version': '2020_10_22',
+        'host': 'localhost',
+        'user-agent': 'kafka-python',
+        'action': 'kafka-cluster:Connect',
+        'x-amz-algorithm': 'AWS4-HMAC-SHA256',
+        'x-amz-credential': 'XXXXXXXXXXXXXXXXXXXX/20210818/us-east-1/kafka-cluster/aws4_request',
+        'x-amz-date': '20210818T212511Z',
+        'x-amz-signedheaders': 'host',
+        'x-amz-expires': '900',
+        'x-amz-signature': 'b0619c50b7ecb4a7f6f92bd5f733770df5710e97b25146f97015c0b1db783b05',
+        'x-amz-security-token': 'XXXXX',
+    }
+    assert actual == expected