Allow List

Overview

The Allow List middleware is a feature designed to restrict access to only specific API endpoints. It rejects requests to endpoints not specifically “allowed”, returning HTTP 403 Forbidden. This enhances the security of the API by preventing unauthorized access to endpoints that are not explicitly permitted.

Note that this is not the same as Tyk’s IP allow list feature, which is used to restrict access to APIs based upon the IP of the requestor.

Use Cases

Restricting access to private endpoints

If you have a service that exposes endpoints or supports methods that you do not want to be available to clients, you should use the allow list to perform strict restriction to a subset of methods and paths. If the allow list is not enabled, requests to endpoints that are not explicitly defined in Tyk will be proxied to the upstream service and may lead to unexpected behavior.

Working

Tyk Gateway does not actually maintain a list of allowed endpoints but rather works on the model whereby if the allow list middleware is added to an endpoint then this will automatically block all other endpoints.

Tyk Gateway will subsequently return HTTP 403 Forbidden to any requested endpoint that doesn’t have the allow list middleware enabled, even if the endpoint is defined and configured in the API definition.

Case sensitivity

By default the allow list is case-sensitive, so for example if you have defined the endpoint GET /userID in your API definition then only calls to GET /userID will be allowed: calls to GET /UserID or GET /userid will be rejected. You can configure the middleware to be case-insensitive at the endpoint level.

You can also set case sensitivity for the entire gateway in the Gateway configuration file tyk.conf. If case insensitivity is configured at the gateway level, this will override the endpoint-level setting.

Endpoint parsing

When using the allow list middleware, we recommend that you familiarize yourself with Tyk’s URL matching options.

If you’re using Tyk OAS APIs, then you can find details and examples of how to configure the allow list middleware here.

If you’re using Tyk Classic APIs, then you can find details and examples of how to configure the allow list middleware here.

Using Tyk OAS

The allow list is a feature designed to restrict access to only specific API endpoints. It rejects requests to endpoints not specifically “allowed”, returning HTTP 403 Forbidden. This enhances the security of the API by preventing unauthorized access to endpoints that are not explicitly permitted.

When working with Tyk OAS APIs the middleware is configured in the Tyk OAS API Definition. You can do this via the Tyk Dashboard API or in the API Designer.

If you’re using the legacy Tyk Classic APIs, then check out the Tyk Classic page.

API Definition

The design of the Tyk OAS API Definition takes advantage of the operationId defined in the OpenAPI Document that declares both the path and method for which the middleware should be added. Endpoint paths entries (and the associated operationId) can contain wildcards in the form of any string bracketed by curly braces, for example /status/{code}. These wildcards are so they are human readable and do not translate to variable names. Under the hood, a wildcard translates to the “match everything” regex of: (.*).

The allow list middleware (allow) can be added to the operations section of the Tyk OAS Extension (x-tyk-api-gateway) in your Tyk OAS API Definition for the appropriate operationId (as configured in the paths section of your OpenAPI Document).

The allow object has the following configuration:

• enabled: enable the middleware for the endpoint
• ignoreCase: if set to true then the path matching will be case insensitive

For example:

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{
    "components": {},
    "info": {
        "title": "example-allow-list",
        "version": "1.0.0"
    },
    "openapi": "3.0.3",
    "paths": {
        "/anything": {
            "get": {
                "operationId": "anythingget",
                "responses": {
                    "200": {
                        "description": ""
                    }
                }
            },
            "put": {
                "operationId": "anythingput",
                "responses": {
                    "200": {
                        "description": ""
                    }
                }
            }
        }
    },
    "x-tyk-api-gateway": {
        "info": {
            "name": "example-allow-list",
            "state": {
                "active": true
            }
        },
        "upstream": {
            "url": "http://httpbin.org/"
        },
        "server": {
            "listenPath": {
                "value": "/example-allow-list/",
                "strip": true
            }
        },
        "middleware": {
            "operations": {
                "anythingget": {
                    "allow": {
                        "enabled": true,
                        "ignoreCase": true
                    }                
                },
                "anythingput": {
                    "allow": {
                        "enabled": true,
                        "ignoreCase": true
                    }                
                }
            }
        }
    }
}

In this example the allow list middleware has been configured for requests to the GET /anything and PUT /anything endpoints. Requests to any other endpoints will be rejected with HTTP 403 Forbidden, unless they also have the allow list middleware enabled. Note that the allow list has been configured to be case insensitive, so calls to GET /Anything will be allowed Note also that the endpoint path has not been terminated with $. Requests to, for example, GET /anything/foobar will be allowed as the regular expression pattern match will recognize this as GET /anything.

The configuration above is a complete and valid Tyk OAS API Definition that you can import into Tyk to try out the allow list feature.

API Designer

Adding the allow list to your API endpoints is easy is easy when using the API Designer in the Tyk Dashboard, simply follow these steps:

1. Add an endpoint

   From the API Designer add an endpoint that matches the path and method to which you want to apply the middleware.

   

   

   

2. Select the Allow List middleware

   Select ADD MIDDLEWARE and choose the Allow List middleware from the Add Middleware screen.

   

3. Optionally configure case-insensitivity

   If you want to disable case-sensitivity for the allow list, then you must select EDIT on the Allow List icon.

   

   This takes you to the middleware configuration screen where you can alter the case sensitivity setting.

   

   Select UPDATE MIDDLEWARE to apply the change to the middleware configuration.

4. Save the API

   Select SAVE API to apply the changes to your API.

Using Classic

The allow list is a feature designed to restrict access to only specific API endpoints. It rejects requests to endpoints not specifically “allowed”, returning HTTP 403 Forbidden. This enhances the security of the API by preventing unauthorized access to endpoints that are not explicitly permitted.

When working with Tyk Classic APIs the middleware is configured in the Tyk Classic API Definition. You can do this via the Tyk Dashboard API or in the API Designer.

If you’re using the newer Tyk OAS APIs, then check out the Tyk OAS page.

API Definition

To enable and configure the allow list you must add a new white_list object to the extended_paths section of your API definition.

The white_list object has the following configuration:

• path: the endpoint path
• method: this should be blank
• ignore_case: if set to true then the path matching will be case insensitive
• method_actions: a shared object used to configure the mock response middleware

The method_actions object should be configured as follows, with an entry created for each allowed method on the path:

• action: this should be set to no_action
• code: this should be set to 200
• headers : this should be blank

For example:

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{
    "extended_paths": {
        "white_list": [
            {
                "disabled": false,
                "path": "/status/200",
                "method": "",
                "ignore_case": false,
                "method_actions": {
                    "GET": {
                        "action": "no_action",
                        "code": 200,
                        "headers": {}
                    },
                    "PUT": {
                        "action": "no_action",
                        "code": 200,
                        "headers": {}
                    }            
                }
            }
        ]
    }
}

In this example the allow list middleware has been configured for HTTP GET and PUT requests to the /status/200 endpoint. Requests to any other endpoints will be rejected with HTTP 403 Forbidden, unless they also have the allow list middleware enabled. Note that the allow list has been configured to be case sensitive, so calls to GET /Status/200 will also be rejected. Note also that the endpoint path has not been terminated with $. Requests to, for example, GET /status/200/foobar will be allowed as the regular expression pattern match will recognize this as GET /status/200.

Consult section configuring the Allow List in Tyk Operator for details on how to configure allow lists for endpoints using Tyk Operator.

API Designer

You can use the API Designer in the Tyk Dashboard to configure the allow list middleware for your Tyk Classic API by following these steps.

1. Add an endpoint for the path and select the plugin

   From the Endpoint Designer, add an endpoint that matches the path for which you want to allow access. Select the Whitelist plugin.

2. Configure the allow list

   Once you have selected the middleware for the endpoint, the only additional feature that you need to configure is whether to make the middleware case insensitive by selecting Ignore Case.

   

3. Save the API

   Use the save or create buttons to save the changes and activate the allow list middleware.

Tyk Operator

Similar to the configuration of a Tyk Classic API Definition you must add a new white_list object to the extended_paths section of your API definition. Furthermore, the use_extended_paths configuration parameter should be set to true.

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apiVersion: tyk.tyk.io/v1alpha1
kind: ApiDefinition
metadata:
  name: httpbin-whitelist
spec:
  name: httpbin-whitelist
  use_keyless: true
  protocol: http
  active: true
  proxy:
    target_url: http://httpbin.org/
    listen_path: /httpbin
    strip_listen_path: true
  version_data:
    default_version: Default
    not_versioned: true
    versions:
      Default:
        name: Default
        use_extended_paths: true
        paths:
          black_list: []
          ignored: []
          white_list: []
        extended_paths:
          white_list:
            - ignore_case: true
              method_actions:
                GET:
                  action: "no_action"
                  code: 200
                  data: ""
                  headers: {}
              path: "/get"

In this example the allow list middleware has been configured for HTTP GET requests to the /get endpoint. Requests to any other endpoints will be rejected with HTTP 403 Forbidden, unless they also have the allow list middleware enabled. Note that the allow list has been configured to case insensitive, so calls to GET /Get will also be accepted. Note also that the endpoint path has not been terminated with $. Requests to, for example, GET /get/foobar will be allowed as the regular expression pattern match will recognize this as GET /get.