feature/secrets-encryption-cleaning (#673)

* removed simple-crypt and cleaned up usage of keys for encryption w/ burnettk

* renamed var to SPIFFWORKFLOW_BACKEND_ENCRYPTION_KEY w/ burnettk

* pyl w/ burnettk

---------

Co-authored-by: jasquat <jasquat@users.noreply.github.com>

spiffworkflow-backend/pyproject.toml

@@ -27,7 +27,6 @@ flask-mail = "*"
 flask-marshmallow = "*"
 flask-migrate = "*"
 flask-restful = "*"
-flask-simple-crypt = "^0.3.3"
 SpiffWorkflow = {git = "https://github.com/sartography/SpiffWorkflow", rev = "main"}
 # SpiffWorkflow = {develop = true, path = "../../spiffworkflow/" }
 # SpiffWorkflow = {develop = true, path = "../../SpiffWorkflow/" }

spiffworkflow-backend/src/spiffworkflow_backend/__init__.py

@@ -1,4 +1,3 @@
-import base64
 import faulthandler
 import json
 import os
@@ -14,7 +13,6 @@ from apscheduler.schedulers.base import BaseScheduler  # type: ignore
 from flask.json.provider import DefaultJSONProvider
 from flask_cors import CORS  # type: ignore
 from flask_mail import Mail  # type: ignore
-from flask_simple_crypt import SimpleCrypt  # type: ignore
 from prometheus_flask_exporter import ConnexionPrometheusMetrics  # type: ignore
 from werkzeug.exceptions import NotFound
 
@@ -111,14 +109,6 @@ def should_start_scheduler(app: flask.app.Flask) -> bool:
     return True
 
 
-class NoOpCipher:
-    def encrypt(self, value: str) -> bytes:
-        return str.encode(value)
-
-    def decrypt(self, value: str) -> str:
-        return value
-
-
 def create_app() -> flask.app.Flask:
     faulthandler.enable()
 
@@ -161,25 +151,6 @@ def create_app() -> flask.app.Flask:
 
     configure_sentry(app)
 
-    encryption_lib = app.config.get("SPIFFWORKFLOW_BACKEND_ENCRYPTION_LIB")
-    if encryption_lib == "cryptography":
-        from cryptography.fernet import Fernet
-
-        app_secret_key = app.config.get("SECRET_KEY")
-        app_secret_key_bytes = app_secret_key.encode()
-        base64_key = base64.b64encode(app_secret_key_bytes)
-        fernet_cipher = Fernet(base64_key)
-        app.config["CIPHER"] = fernet_cipher
-    # for comparison against possibly-slow encryption libraries
-    elif encryption_lib == "no_op_cipher":
-        no_op_cipher = NoOpCipher()
-        app.config["CIPHER"] = no_op_cipher
-    else:
-        simple_crypt_cipher = SimpleCrypt()
-        app.config["FSC_EXPANSION_COUNT"] = 2048
-        simple_crypt_cipher.init_app(app)
-        app.config["CIPHER"] = simple_crypt_cipher
-
     app.before_request(verify_token)
     app.before_request(AuthorizationService.check_for_permission)
     app.after_request(_set_new_access_token_in_cookie)

spiffworkflow-backend/src/spiffworkflow_backend/config/__init__.py

@@ -1,4 +1,5 @@
 """__init__.py."""
+import base64
 import os
 import threading
 import uuid
@@ -11,12 +12,21 @@ from spiffworkflow_backend.services.logging_service import setup_logger
 
 HTTP_REQUEST_TIMEOUT_SECONDS = 15
 CONNECTOR_PROXY_COMMAND_TIMEOUT = 45
+SUPPORTED_ENCRYPTION_LIBS = ["cryptography", "no_op_cipher"]
 
 
 class ConfigurationError(Exception):
     pass
 
 
+class NoOpCipher:
+    def encrypt(self, value: str) -> bytes:
+        return str.encode(value)
+
+    def decrypt(self, value: str) -> str:
+        return value
+
+
 def setup_database_configs(app: Flask) -> None:
     worker_id = os.environ.get("PYTEST_XDIST_WORKER")
     parallel_test_suffix = ""
@@ -134,6 +144,33 @@ def _check_for_incompatible_frontend_and_backend_urls(app: Flask) -> None:
     )
 
 
+def _setup_cipher(app: Flask) -> None:
+    encryption_lib = app.config.get("SPIFFWORKFLOW_BACKEND_ENCRYPTION_LIB")
+    if encryption_lib not in SUPPORTED_ENCRYPTION_LIBS:
+        raise ConfigurationError(
+            f"Received invalid encryption lib: {encryption_lib}. Supported libs are {SUPPORTED_ENCRYPTION_LIBS}"
+        )
+
+    if encryption_lib == "cryptography":
+        from cryptography.fernet import Fernet
+
+        app_secret_key = app.config.get("SPIFFWORKFLOW_BACKEND_ENCRYPTION_KEY")
+        if app_secret_key is None:
+            raise ConfigurationError(
+                "SPIFFWORKFLOW_BACKEND_ENCRYPTION_KEY must be specified if using cryptography encryption lib"
+            )
+
+        app_secret_key_bytes = app_secret_key.encode()
+        base64_key = base64.b64encode(app_secret_key_bytes)
+        fernet_cipher = Fernet(base64_key)
+        app.config["CIPHER"] = fernet_cipher
+
+    # no_op_cipher for comparison against possibly-slow encryption libraries
+    elif encryption_lib == "no_op_cipher":
+        no_op_cipher = NoOpCipher()
+        app.config["CIPHER"] = no_op_cipher
+
+
 def setup_config(app: Flask) -> None:
     # ensure the instance folder exists
     try:
@@ -211,3 +248,4 @@ def setup_config(app: Flask) -> None:
     _set_up_tenant_specific_fields_as_list_of_strings(app)
     _check_for_incompatible_frontend_and_backend_urls(app)
     _check_extension_api_configs(app)
+    _setup_cipher(app)

spiffworkflow-backend/src/spiffworkflow_backend/config/default.py

@@ -162,6 +162,7 @@ config_from_env(
     "SPIFFWORKFLOW_BACKEND_ENCRYPTION_LIB",
     default="no_op_cipher",
 )
+config_from_env("SPIFFWORKFLOW_BACKEND_ENCRYPTION_KEY")
 
 ### locking
 # timeouts for process instances locks as they are run to avoid stale locks

spiffworkflow-backend/src/spiffworkflow_backend/config/unit_testing.py

@@ -3,7 +3,6 @@ import os
 from os import environ
 
 TESTING = True
-SECRET_KEY = "the_secret_key"  # noqa: S105, do not care about security when running unit tests
 SPIFFWORKFLOW_BACKEND_LOG_TO_FILE = environ.get("SPIFFWORKFLOW_BACKEND_LOG_TO_FILE", default="true") == "true"
 
 SPIFFWORKFLOW_BACKEND_PERMISSIONS_FILE_NAME = environ.get(

spiffworkflow-backend/src/spiffworkflow_backend/models/user.py

@@ -52,7 +52,8 @@ class UserModel(SpiffworkflowBaseDBModel):
 
         :return: string
         """
-        secret_key = current_app.config.get("SECRET_KEY")
+        # current_app.secret_key is the same as current_app.config['SECRET_KEY']
+        secret_key = str(current_app.secret_key)
         if secret_key is None:
             raise KeyError("we need current_app.config to have a SECRET_KEY")
 

spiffworkflow-backend/src/spiffworkflow_backend/services/authentication_service.py

@@ -153,7 +153,7 @@ class AuthenticationService:
         self, code: str, authentication_identifier: str, redirect_url: str = "/v1.0/login_return"
     ) -> dict:
         backend_basic_auth_string = (
-            f"{self.client_id(authentication_identifier)}:{self.secret_key(authentication_identifier)}"
+            f"{self.client_id(authentication_identifier)}:{self.__class__.secret_key(authentication_identifier)}"
         )
         backend_basic_auth_bytes = bytes(backend_basic_auth_string, encoding="ascii")
         backend_basic_auth = base64.b64encode(backend_basic_auth_bytes)
@@ -300,10 +300,7 @@ class AuthenticationService:
 
     @staticmethod
     def decode_auth_token(auth_token: str) -> dict[str, str | None]:
-        secret_key = current_app.config.get("SECRET_KEY")
-        if secret_key is None:
-            raise KeyError("we need current_app.config to have a SECRET_KEY")
-
+        """This is only used for debugging."""
         try:
             payload: dict[str, str | None] = jwt.decode(auth_token, options={"verify_signature": False})
             return payload