Add service token authentication mechanism

Author: abs51295

openshift/template.yaml

@@ -95,6 +95,11 @@ objects:
               configMapKeyRef:
                 name: bayesian-config
                 key: keycloak-url
+          - name: BAYESIAN_AUTH_PUBLIC_KEYS_URL
+            valueFrom:
+              configMapKeyRef:
+                name: bayesian-config
+                key: auth-url
           - name: BAYESIAN_JWT_AUDIENCE
             value: "fabric8-online-platform,openshiftio-public"
           image: "${DOCKER_REGISTRY}/${DOCKER_IMAGE}:${IMAGE_TAG}"

src/auth.py

@@ -5,12 +5,11 @@
 import jwt
 from os import getenv
 
-
 from exceptions import HTTPError
-from utils import fetch_public_key
+from utils import fetch_public_key, fetch_service_public_keys
 
 
-def decode_token(token):
+def decode_user_token(token):
     """Decode the authorization token read from the request header."""
     if token is None:
         return {}
@@ -38,6 +37,40 @@ def decode_token(token):
     return decoded_token
 
 
+def decode_service_token(token):  # pragma: no cover
+    """Decode OSIO service token."""
+    # TODO: Merge this function and user token function once audience is removed from user tokens.
+    if token is None:
+        return {}
+
+    if token.startswith('Bearer '):
+        _, token = token.split(' ', 1)
+
+    pub_keys = fetch_service_public_keys(current_app)
+    decoded_token = None
+
+    # Since we have multiple public keys, we need to verify against every public key.
+    # Token can be decoded by any one of the available public keys.
+    for pub_key in pub_keys:
+        try:
+            pub_key = pub_key.get("key", "")
+            pub_key = '-----BEGIN PUBLIC KEY-----\n{pkey}\n-----END PUBLIC KEY-----'\
+                .format(pkey=pub_key)
+            decoded_token = jwt.decode(token, pub_key, algorithms=['RS256'])
+        except jwt.InvalidTokenError:
+            current_app.logger.error("Auth token couldn't be decoded for public key: {}"
+                                     .format(pub_key))
+            decoded_token = None
+
+        if decoded_token:
+            break
+
+    if not decoded_token:
+        raise jwt.InvalidTokenError('Auth token cannot be verified.')
+
+    return decoded_token
+
+
 def get_token_from_auth_header():
     """Get the authorization token read from the request header."""
     return request.headers.get('Authorization')
@@ -62,7 +95,37 @@ def wrapper(*args, **kwargs):
         lgr = current_app.logger
 
         try:
-            decoded = decode_token(get_token_from_auth_header())
+            decoded = decode_user_token(get_token_from_auth_header())
+            if not decoded:
+                lgr.exception('Provide an Authorization token with the API request')
+                raise HTTPError(401, 'Authentication failed - token missing')
+
+            lgr.info('Successfuly authenticated user {e} using JWT'.
+                     format(e=decoded.get('email')))
+        except jwt.ExpiredSignatureError as exc:
+            lgr.exception('Expired JWT token')
+            raise HTTPError(401, 'Authentication failed - token has expired') from exc
+        except Exception as exc:
+            lgr.exception('Failed decoding JWT token')
+            raise HTTPError(401, 'Authentication failed - could not decode JWT token') from exc
+
+        return view(*args, **kwargs)
+
+    return wrapper
+
+
+def service_token_required(view):  # pragma: no cover
+    """Check if the request contains a valid service token."""
+    @wraps(view)
+    def wrapper(*args, **kwargs):
+        # Disable authentication for local setup
+        if getenv('DISABLE_AUTHENTICATION') in ('1', 'True', 'true'):
+            return view(*args, **kwargs)
+
+        lgr = current_app.logger
+
+        try:
+            decoded = decode_service_token(get_token_from_auth_header())
             if not decoded:
                 lgr.exception('Provide an Authorization token with the API request')
                 raise HTTPError(401, 'Authentication failed - token missing')

src/rest_api.py

@@ -4,7 +4,7 @@
 from flask_cors import CORS
 from utils import DatabaseIngestion, scan_repo, validate_request_data, retrieve_worker_result
 from f8a_worker.setup_celery import init_selinon
-from auth import login_required
+from auth import login_required, service_token_required
 from exceptions import HTTPError
 
 app = Flask(__name__)
@@ -160,7 +160,7 @@ def user_repo_scan():
 
 
 @app.route('/api/v1/user-repo/notify', methods=['POST'])
-@login_required
+@service_token_required
 def notify_user():
     """
     Endpoint for notifying security vulnerability in a repository.

src/utils.py

@@ -292,3 +292,28 @@ def fetch_public_key(app):
             app.public_key = None
 
     return app.public_key
+
+
+def fetch_service_public_keys(app):  # pragma: no cover
+    """Get public keys for OSIO service account. Currently, there are three public keys."""
+    if not getattr(app, "service_public_keys", []):
+        auth_url = os.getenv('BAYESIAN_AUTH_PUBLIC_KEYS_URL', '')
+        if auth_url:
+            try:
+                auth_url = auth_url.strip('/') + '/api/token/keys?format=pem'
+                result = requests.get(auth_url, timeout=0.5)
+                app.logger.info('Fetching public key from %s, status %d, result: %s',
+                                auth_url, result.status_code, result.text)
+            except requests.exceptions.Timeout:
+                app.logger.error('Timeout fetching public key from %s', auth_url)
+                return ''
+            if result.status_code != 200:
+                return ''
+
+            keys = result.json().get('keys', [])
+            app.service_public_keys = keys
+
+        else:
+            app.service_public_keys = None
+
+    return app.service_public_keys

tests/test_auth.py

@@ -68,39 +68,39 @@ def mocked_get_audiences_3():
 @patch("auth.fetch_public_key", side_effect=mocked_fetch_public_key_1)
 def test_decode_token_invalid_input_1(mocked_fetch_public_key, mocked_get_audiences):
     """Test the invalid input handling during token decoding."""
-    assert decode_token(None) == {}
+    assert decode_user_token(None) == {}
 
 
 @patch("auth.get_audiences", side_effect=mocked_get_audiences)
 @patch("auth.fetch_public_key", side_effect=mocked_fetch_public_key_1)
 def test_decode_token_invalid_input_2(mocked_fetch_public_key, mocked_get_audiences):
     """Test the invalid input handling during token decoding."""
     with pytest.raises(Exception):
-        assert decode_token("Foobar") is None
+        assert decode_user_token("Foobar") is None
 
 
 @patch("auth.get_audiences", side_effect=mocked_get_audiences)
 @patch("auth.fetch_public_key", side_effect=mocked_fetch_public_key_1)
 def test_decode_token_invalid_input_3(mocked_fetch_public_key, mocked_get_audiences):
     """Test the invalid input handling during token decoding."""
     with pytest.raises(Exception):
-        assert decode_token("Bearer ") is None
+        assert decode_user_token("Bearer ") is None
 
 
 @patch("auth.get_audiences", side_effect=mocked_get_audiences)
 @patch("auth.fetch_public_key", side_effect=mocked_fetch_public_key_2)
 def test_decode_token_invalid_input_4(mocked_fetch_public_key, mocked_get_audiences):
     """Test the invalid input handling during token decoding."""
     with pytest.raises(Exception):
-        assert decode_token("Bearer ") is None
+        assert decode_user_token("Bearer ") is None
 
 
 @patch("auth.get_audiences", side_effect=mocked_get_audiences_2)
 @patch("auth.fetch_public_key", side_effect=mocked_fetch_public_key_2)
 def test_decode_token_invalid_input_5(mocked_fetch_public_key, mocked_get_audiences):
     """Test the handling wrong JWT tokens."""
     with pytest.raises(Exception):
-        assert decode_token("Bearer something") is None
+        assert decode_user_token("Bearer something") is None
 
 
 @patch("auth.get_audiences", side_effect=mocked_get_audiences_3)
@@ -112,7 +112,7 @@ def test_decode_token_invalid_input_6(mocked_fetch_public_key, mocked_get_audien
         'aud': 'foo:bar'
     }
     token = jwt.encode(payload, PRIVATE_KEY, algorithm='RS256').decode("utf-8")
-    assert decode_token(token) is not None
+    assert decode_user_token(token) is not None
 
 
 def test_audiences():