From dee42dd14dc7786b1ccf9465bb28dfe74024166c Mon Sep 17 00:00:00 2001
From: Frederick Muriuki Muriithi
Date: Thu, 9 Mar 2023 04:39:37 +0300
Subject: auth: introspection: Protect introspection endpoint

The introspection endpoint could contain privileged information, thus requires
that the endpoint be protected. This commit ensures that a user has
authenticated to the system and that the client they are using be one of the
allowed clients.
---
 gn3/auth/authentication/oauth2/views.py | 19 +++++++++++++++----
 gn3/auth/authorisation/errors.py        |  4 ++++
 gn3/settings.py                         | 15 +++++++++++++--
 3 files changed, 32 insertions(+), 6 deletions(-)

(limited to 'gn3')

diff --git a/gn3/auth/authentication/oauth2/views.py b/gn3/auth/authentication/oauth2/views.py
index e440c6e..3a14a48 100644
--- a/gn3/auth/authentication/oauth2/views.py
+++ b/gn3/auth/authentication/oauth2/views.py
@@ -1,8 +1,11 @@
 """Endpoints for the oauth2 server"""
 import uuid
 
-from flask import Blueprint, current_app as app
+from flask import Response, Blueprint, current_app as app
 
+from gn3.auth.authorisation.errors import ForbiddenAccess
+
+from .resource_server import require_oauth
 from .endpoints.revocation import RevocationEndpoint
 from .endpoints.introspection import IntrospectionEndpoint
 
@@ -36,7 +39,15 @@ def revoke_token():
         RevocationEndpoint.ENDPOINT_NAME)
 
 @auth.route("/introspect", methods=["POST"])
-def introspect_token():
+@require_oauth("introspect")
+def introspect_token() -> Response:
     """Provide introspection information for the token."""
-    return app.config["OAUTH2_SERVER"].create_endpoint_response(
-        IntrospectionEndpoint.ENDPOINT_NAME)
+    # This is dangerous to provide publicly
+    authorised_clients = app.config.get(
+        "OAUTH2_CLIENTS_WITH_INTROSPECTION_PRIVILEGE", [])
+    with require_oauth.acquire("introspect") as the_token:
+        if the_token.client.client_id in authorised_clients:
+            return app.config["OAUTH2_SERVER"].create_endpoint_response(
+                IntrospectionEndpoint.ENDPOINT_NAME)
+
+    raise ForbiddenAccess("You cannot access this endpoint")
diff --git a/gn3/auth/authorisation/errors.py b/gn3/auth/authorisation/errors.py
index ff28cd4..3bc7a04 100644
--- a/gn3/auth/authorisation/errors.py
+++ b/gn3/auth/authorisation/errors.py
@@ -8,6 +8,10 @@ class AuthorisationError(Exception):
     """
     error_code: int = 400
 
+class ForbiddenAccess(AuthorisationError):
+    """Raised for forbidden access."""
+    error_code: int = 403
+
 class UserRegistrationError(AuthorisationError):
     """Raised whenever a user registration fails"""
 
diff --git a/gn3/settings.py b/gn3/settings.py
index 1de4d27..1b4a105 100644
--- a/gn3/settings.py
+++ b/gn3/settings.py
@@ -1,7 +1,7 @@
 """Configuration settings for this project"""
-
-import tempfile
 import os
+import uuid
+import tempfile
 
 BCRYPT_SALT = "$2b$12$mxLvu9XRLlIaaSeDxt8Sle"  # Change this!
 DATA_DIR = ""
@@ -70,3 +70,14 @@ MULTIPROCESSOR_PROCS = 6 # Number of processes to spawn
 AUTH_MIGRATIONS = "migrations/auth"
 AUTH_DB = os.environ.get(
     "AUTH_DB", f"{os.environ.get('HOME')}/genenetwork/gn3_files/db/auth.db")
+
+try:
+    # *** SECURITY CONCERN ***
+    # Clients with access to this privileges create a security concern.
+    # Be careful when adding to this configuration
+    OAUTH2_CLIENTS_WITH_INTROSPECTION_PRIVILEGE = tuple(
+        uuid.UUID(client_id) for client_id in
+        os.environ.get(
+            "OAUTH2_CLIENTS_WITH_INTROSPECTION_PRIVILEGE", "").split(","))
+except ValueError as _valerr:
+    OAUTH2_CLIENTS_WITH_INTROSPECTION_PRIVILEGE = tuple()
-- 
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