Check ip unit test and modify ways to parse IP address

app/authentication/auth.py

@@ -46,10 +46,10 @@ def requires_no_auth():
 
 def restrict_ip_sms():
     ip = ''
-    if request.headers.getlist("X-Forwarded-For"):
-        ip0 = request.headers.getlist("X-Forwarded-For")
-        ip1 = ip0.split(',')
-        ip = ip1[0]
+    if request.headers.get("X-Forwarded-For"):
+        # X-Forwarded-For looks like "203.0.113.195, 70.41.3.18, 150.172.238.178"
+        ip_list = request.headers.get("X-Forwarded-For")
+        ip = ip_list.split(',')[0].strip()
 
     if ip in current_app.config.get('ALLOW_IP_INBOUND_SMS'):
         current_app.logger.info("Inbound sms ip addresses {} passed ".format(ip))

tests/app/authentication/test_authentication.py

@@ -4,6 +4,7 @@ import time
 from datetime import datetime
 
 import pytest
+import flask
 from flask import json, current_app
 from freezegun import freeze_time
 from notifications_python_client.authentication import create_jwt_token
@@ -11,6 +12,7 @@ from notifications_python_client.authentication import create_jwt_token
 from app import api_user
 from app.dao.api_key_dao import get_unsigned_secrets, save_model_api_key, get_unsigned_secret, expire_api_key
 from app.models import ApiKey, KEY_TYPE_NORMAL
+from app.authentication.auth import restrict_ip_sms, AuthError
 
 
 # Test the require_admin_auth and require_auth methods
@@ -305,3 +307,46 @@ def test_should_return_403_when_token_is_expired(client,
 def __create_token(service_id):
     return create_jwt_token(secret=get_unsigned_secrets(service_id)[0],
                             client_id=str(service_id))
+
+
+@pytest.fixture
+def restrict_ip_sms_app():
+    app = flask.Flask(__name__)
+    app.config['TESTING'] = True
+    app.config['ALLOW_IP_INBOUND_SMS'] = ['111.111.111.111']
+
+    blueprint = flask.Blueprint('restrict_ip_sms_app', __name__)
+
+    @blueprint.route('/')
+    def test_endpoint():
+        return 'OK', 200
+
+    blueprint.before_request(restrict_ip_sms)
+    app.register_blueprint(blueprint)
+
+    with app.test_request_context(), app.test_client() as client:
+        yield client
+
+
+def test_allow_valid_ips(restrict_ip_sms_app):
+    response = restrict_ip_sms_app.get(
+        path='/',
+        headers=[
+            ('X-Forwarded-For', '111.111.111.111, 222.222.222.222, 127.0.0.1'),
+        ]
+    )
+
+    assert response.status_code == 200
+
+
+@pytest.mark.xfail(reason='Currently not blocking invalid IPs', strict=True)
+def test_reject_invalid_ips(restrict_ip_sms_app):
+    with pytest.raises(AuthError) as exc_info:
+        restrict_ip_sms_app.get(
+            path='/',
+            headers=[
+                ('X-Forwarded-For', '222.222.222.222, 111.111.111.111, 127.0.0.1')
+            ]
+        )
+
+    assert exc_info.value.short_message == 'Unknown source IP address from the SMS provider'