Security

Gateway API Authentication

The Gateway’s REST API is what the API Manager invokes when publishing APIs and Client Apps to the Gateway [1].

The quickstart configurations should work out of the box, but they assume the locality of all components, including Keycloak. Real deployments will likely need to perform some reconfiguration.

This REST API should be protected, often using BASIC authentication.

By default, the Gateway REST API requires BASIC authentication credentials, as well as a role of apipublisher. In other words, the Gateway REST API can only be invoked by a valid user, and that user must have the apipublisher role.

The Keycloak client for this API is apiman-gateway-api, and the default user and password are: apimanager/apiman123!

Setup

For the Vert.x gateway, the simplest way to retrieve the necessary configuration is to generate it from your Keycloak server [1]:

The gateway accepts Keycloak’s generated JSON, allowing you to paste your chosen client configuration from the Keycloak console into the auth.config section.

To retrieve it:

  1. Log into Keycloak (e.g. http://localhost:8080/auth).

  2. Clientsapiman-gateway-apiInstallation.

  3. Select Keycloak OIDC JSON for Format Option.

  4. Copy the contents and merge into the config selection where indicated below.

The precise configuration you need to provide will vary depending upon your Keycloak setup.

Due to a current limitation in the underlying OAuth2 library you may be required to provide a credentials section to avoid issues. You can change your client type to confidential, or simply provide a dummy credentials section.
"auth": {
  "type": "keycloak",
  "config": {
    "flowType": "PASSWORD",
    "requiredRole": "realm:apipublisher",
    // Paste and overwrite your Keycloak config here.
    "realm": "apiman",
    "realm-public-key": "<snip>",
    "auth-server-url": "http://localhost:8080/auth",
    "ssl-required": "none",
    "resource": "apiman-gateway-api",
    // A limitation in the current OAuth2 implementation means a credentials section is required
    // even if your client is not set to "confidential". Leave this dummy section if you're using non-confidential.
    "credentials": {
      "secret": "217b725d-7790-47a7-a3fc-5cf31f92a8db"
    }
    // End paste here
  }
}

1. Normally located at http://localhost:8080/auth if you’re using the quickstart

The API Gateway has a REST based configuration API which the API Manager uses when publishing APIs to it. This API is protected by Keycloak authentication. The configuration included in the apiman quickstart overlay ZIP assumes that the Keycloak server is local, so you’ll need to modify the standalone-apiman.xml file to point to the remote Keycloak instance.

Here is the relevant portion of the standalone-apiman.xml file that you must change:

<realm name="apiman">
  <realm-public-key>MIIB..snip..QAB</realm-public-key>
  <auth-server-url>https://keycloak-host.org:8443/auth</auth-server-url>
  <ssl-required>none</ssl-required>
  <enable-cors>false</enable-cors>
  <principal-attribute>preferred_username</principal-attribute>
</realm>

MTLS (Mutual SSL) Endpoint Security

If you wish to use mutual SSL to ensure endpoint security between the apiman API Gateway and your back-end API(s), you must update some settings.

High Level Overview

  1. Create Trust and Key Stores

  2. Make changes to your config file

  3. (Re)start apiman!

  4. Configure one or more API to use MTLS

Create Trust and Key Stores

Please refer to official JDK documentation to learn how to create and managed your SSL Trust and Key stores. Minimally a Keystore is required in order to successfully utilise MTLS, and in many cases also a Truststore.

A keystore contains a given node’s private key material, and must be kept safe. Each node should have a unique key entry. For instance, a gateway should have its own keystore, and each API likewise. In a production system, these keys should be issued by a trusted certificate authority.

A truststore typically contains a set of certificate authorities which are trusted issuers. Therefore, any certificate signed by the trusted CA would be trusted by the gateway. If no truststore is explicitly provided to apiman the default trusted certificates provided by the JVM will be used. A typical use-case would be that an organization’s internal signing authority is marked as trusted within in the truststore, and as the authority has been used to sign the certificate material in the keystores, they will mutually trust each other by virtue of the issuer.

It is also possible to directly insert the public/self-signed certificate corresponding to a given private key pair into a truststore, which works well at small scales and for development, but will quickly cause the accumulation of a huge number of certificates in larger systems as it requires a 1:1 mapping of certificates and private keys (rather than 1:N by using a trusted authority).

Your back-end APIs must be SSL enabled and require authenticated client SSL connections. This means you must have server SSL certificates generated (and appropriate certificates and/or CAs stored in your Trust Store).

Example Scenarios

There are many potential configuration permutations, but we’ll outline a few simple ones here to get you started. You should research the best options to meet your security and deployment requirements.

Development Setup

In our hypothetical development setup, let’s imagine we have two APIs and a single gateway.

Table 1. Simple Development MTLS Setup
Component Key Alias Truststore’s Trusted Certificates

Apiman Gateway

gateway

api_a.cer, api_b.cer

API A

api_a

gateway.cer

API B

api_b

gateway.cer

Walkthrough
  • Generate a keystore and export a certificate for each component:

    • Gateway:

      keytool -genkey -keyalg RSA -keystore gateway_ks.jks -alias gateway
      keytool -export -alias gateway -file gateway.cer -keystore gateway_ks.jks
    • API A:

      keytool -genkey -keyalg RSA -keystore api_a_ks.jks -alias api_a
      keytool -export -alias api_a -file api_a.cer -keystore api_a_ks.jks
    • API B:

      keytool -genkey -keyalg RSA -keystore api_b_ks.jks -alias api_b
      keytool -export -alias api_b -file api_b.cer -keystore api_b_ks.jks
  • Import certificates into appropriate trust stores:

    • Gateway:

      keytool -import -file api_a.cer -alias api_a -keystore gateway_ts.jks
      keytool -import -file api_b.cer -alias api_b -keystore gateway_ts.jks
    • API A:

      keytool -import -file gateway.cer -alias gateway -keystore api_a_ts.jks
    • API B:

      keytool -import -file gateway.cer -alias gateway -keystore api_b_ts.jks

Now simply set the appropriate paths to the keystore and truststore in apiman.properties for the gateway, and set up your APIs with their respective truststores and keystores (the specifics of how to do this will depend on your API’s implementation).

We will also set the following in apiman.properties to make our development easier:

apiman-gateway.connector-factory.tls.allowAnyHost=true

When you add your MTLS protected APIs into apiman, you should set the API Security field to MTLS/Two-Way-SSL.

MTLS via Custom Certificate Authority

The previous approach works for development, but doesn’t scale well, is harder to manage and doesn’t gracefully handle revocations, expiry, expansion, etc. Instead, let’s summarise a scenario where an organisation has an internal CA which they use to sign APIs' certificates. The process for generating a CA and signing certificates is out of scope for this guide, but is trivial to accomplish using OpenSSL, LibreSSL, or similar.

Let’s imagine we have a CA called apimanCA, and have signed the certificates for each node.

Table 2. CA-based MTLS Setup
Component Signed Key Alias Truststore Contents

Apiman Gateway

gateway (signed by apimanCA)

apimanCA.cer

API A

api_a (signed by apimanCA)

apimanCA.cer

API N

api_n (signed by apimanCA)

apimanCA.cer

Despite the initial administrative work setting up the CA and signing the certificates, this process is drastically less effort to maintain in large deployments. Only the trusted CA needs to be in the truststore, and any certificates signed by it are trusted by virtue of this.

Make changes to configuration

Once you have your Trust Store and Key Store properly configured, you must alter your configuration file. Here is a summary of the properties:

Omit any properties which are not relevant to you, with the exception of trustStore, which is mandatory for MTLS.

The settings chosen here have significant security implications. Best practice guides are available at OWASP.
Conf JSON
{
  "connector-factory": {
    "class": "io.apiman.gateway.platforms.vertx3.connector.ConnectorFactory",
    "config": {
      "tls": {
        // Whether self-signed certificates should be automatically trusted. *Use with care.*
        //"allowSelfSigned": true,

        // Developer mode (bypass almost all security checks). *Use with care.*
        //"devMode": false,

        // Whether certificate host checks should be bypassed. *Use with care.*
        //"allowAnyHost": true,

        // Trust store contains certificate(s) trusted by gateway.
        "trustStore": "/path/to/your/truststore.jks",
        "trustStorePassword": "abc123",

        // Key store contains gateway's keys.
        "keyStore": "/path/to/your/keystore.jks",
        "keyStorePassword": "abc123"

        // By default all keys can be used (will try all).
        // If alias list provided, will only attempt to use listed keys.
        //"keyAliases": "mykey,myotherkey",

        // Allowed TLS/SSL protocols and ciphers suites as CSV.
        // Availability will vary depending on your JVM impl.
        // Uses JVM defaults depending if not explicitly provided.
        // See: https://docs.oracle.com/javase/8/docs/technotes/guides/security/SunProviders.html
        //"allowedProtocols": "TLSv1.2,TLSv1.1",
        //"allowedCiphers": "TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,...",
        //"disallowedCiphers": "..."
      }
    }
  }
}
apiman.properties
# ---------------------------------------------------------------------
# SSL/TLS settings for the gateway connector(s).
# ---------------------------------------------------------------------

# Trust store contains certificate(s) trusted by gateway.
apiman-gateway.connector-factory.tls.trustStore=<PATH_TO_TRUST_STORE>
apiman-gateway.connector-factory.tls.trustStorePassword=<PASSWORD_IF_ANY>

# Key store contains gateway's keys (including private components: keep it safe).
apiman-gateway.connector-factory.tls.keyStore=<PATH_TO_KEY_STORE>
apiman-gateway.connector-factory.tls.keyStorePassword=<PASSWORD_IF_ANY> # Password on key store as a whole
apiman-gateway.connector-factory.tls.keyPassword=<PASSWORD_IF_ANY> # Password on specific key(s)
# By default all keys can be used (will try all). If alias list provided, will only attempt to use listed keys.
apiman-gateway.connector-factory.tls.keyAliases=<COMMA_SEPARATED_LIST>

# Allowed TLS/SSL protocols and ciphers suites as CSV. Availability will vary depending on your JVM impl.
# Uses JVM defaults depending if not explicitly provided.
# See: https://docs.oracle.com/javase/7/docs/technotes/guides/security/SunProviders.html
apiman-gateway.connector-factory.tls.allowedProtocols=TLSv1.2,TLSv1.1
apiman-gateway.connector-factory.tls.allowedCiphers=TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,...

# Whether certificate host checks should be bypassed. *Use with great care.*
apiman-gateway.connector-factory.tls.allowAnyHost=false

# Whether self-signed certificates should be automatically trusted. *Use with great care.*
apiman-gateway.connector-factory.tls.allowSelfSigned=false

(Re)start apiman

If apiman was running, you should stop it now. Once everything is shutdown, and the changes to apiman.properties have been made, go ahead and start apiman up again.

Configure one or more API to use MTLS

Now that the apiman MTLS feature has been configured, use the Manager UI to enable MTLS in one or more API. This can be done on the "Implementation" tab when you are configuring the details of your back-end endpoint (URL, type, and endpoint security).


1. Some advanced configurations may interact directly with the Gateway API, whilst others may bypass it entirely by using polling, etc.

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