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Zowe API Mediation Layer Security

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Zowe API Mediation Layer Security

How API ML transport security works#

Security within the API Mediation Layer (API ML) is performed on several levels. This article describes how API ML uses Transport Layer Security (TLS). As a system administrator or API developer, use this guide to familiarize yourself with the following security concepts:

Transport layer security#

Secure data during data-transport by using the TLS protocol for all connections to API Mediation Layer services. While it is possible to disable the TLS protocol for debugging purposes or other use-cases, the enabled TLS protocol is the default mode.

Authentication#

Authentication is the method of how an entity, whether it be a user (API Client) or an application (API Service), proves its true identity.

API ML uses the following authentication methods:

  • User ID and password

    • The user ID and password are used to retrieve authentication tokens.
    • Requests originate from a user.
    • The user ID and password are validated by a z/OS security manager and a token is issued that is then used to access the API service.

  • TLS client certificates

    • Certificates are for service-only requests.

Zowe API ML services#

The following range of service types apply to the Zowe™ API ML:

  • Zowe API ML services

    • Gateway Service (GW) The Gateway is the access point for API clients that require access to API services. API services can be accessed through the Gateway by API Clients. The Gateway receives information about an API Service from the Discovery Service.

    • Discovery Service (DS) The Discovery Service collects information about API services and provides this information to the Gateway and other services. API ML internal services are also registered to the Discovery Service.

    • API Catalog (AC) The Catalog displays information about API services through a web UI. The Catalog receives information about an API service from the Discovery Service.

  • Authentication and Authorization Service (AAS)

    AAS provides authentication and authorization functionality to check user access to resources on z/OS. The API ML uses z/OSMF API for authentication. For more information, see: APIML wiki

  • API Clients

    External applications, users, or other API services that are accessing API services via the API Gateway

  • API Services

    Applications that are accessed through the API Gateway. API services register themselves to the Discovery Service and can access other services through the Gateway. If an API service is installed in such a way that direct access is possible, API services can access other services without the Gateway. When APIs access other services, they can also function as API clients.

Zowe API ML TLS requirements#

The API ML TLS requires servers to provide HTTPS ports. Each of the API ML services has the following specific requirements:

  • API Client

    • The API Client is not a server
    • Requires trust of the API Gateway
    • Has a truststore that contains certificates required to trust the Gateway

  • Gateway Service

    • Provides an HTTPS port
    • Has a keystore with a server certificate
      • The certificate needs to be trusted by API Clients
      • This certificate should be trusted by web browsers because the API Gateway can be used to display web UIs
    • Has a truststore that contains certificates needed to trust API Services

  • API Catalog

    • Provides an HTTPS port
    • Has a keystore with a server certificate
      • The certificate needs to be trusted by the API Gateway
      • This certificate does not need to be trusted by anyone else

  • Discovery Service

    • Provides an HTTPS port
    • Has a keystore with a server certificate
      • The certificate needs to be trusted by API Clients
    • Has a truststore that contains certificates needed to trust API services

  • API Service

    • Provides an HTTPS port
    • Has a keystore with a server and client certificate
      • The server certificate needs to be trusted by the Gateway
      • The client certificate needs to be trusted by the Discovery Service
      • The client and server certificates can be the same
      • These certificates do not need to be trusted by anyone else
    • Has a truststore that contains one or more certificates that are required to trust the Gateway and Discovery Service

Authentication for API ML services#

  • API Gateway

    • API Gateway handles authentication.
    • There are two authentication endpoints that allow to authenticate the resource by providers
    • Diagnostic endpoints /application/** in API Gateway are protected by basic authentication or Zowe JWT token.

  • API Catalog

    • API Catalog is accessed by users and requires protection by a login
    • Protected access is performed by the Authentication and Authorization Service

  • Discovery Service

    • Discovery Service is accessed by API Services
    • This access (reading information and registration) requires protection needs by a client certificate
    • (Optional) Access can be granted to users (administrators)
    • Diagnostic endpoints /application/** in Discovery Service are protected by basic authentication or Zowe JWT token.

  • API Services

    • Authentication is service-dependent
    • Recommended to use the Authentication and Authorization Service for authentication

Authentication endpoints#

The API Gateway contains two REST API authentication endpoints: auth/login and auth/query.

The /login endpoint authenticates mainframe user credentials and returns an authentication token. The login request requires user credentials though one of the following methods:

  • Basic access authentication
  • JSON with user credentials

When authentication is successful the response to the request is an empty body and a token is contained in a secure HttpOnly cookie named apimlAuthenticationToken. When authentication fails, a user gets a 401 status code.

The /query endpoint validates the token and retrieves the information associated with the token. The query request requires the token through one of the following methods:

  • A cookie named apimlAuthenticationToken
  • Bearer authentication

When authentication is successful the response to the request is a JSON object which contains information associated with the token. When authentication fails, a user gets a 401 status code.

The /ticket endpoint generates a PassTicket for the user associated with a token.

This endpoint is protected by a client certificate. The ticket request requires the token in one of the following formats:

  • Cookie named apimlAuthenticationToken.
  • Bearer authentication

The request takes one parameter named applicationName, the name of the application for which the PassTicket should be generated. This parameter must be supplied.

The response is a JSON object, which contains information associated with the ticket.

For more details, see the OpenAPI documentation of the API Mediation Layer in the API Catalog.

Authentication providers#

API ML contains the following providers to handle authentication for the API Gateway:

  • z/OSMF Authentication Provider
  • Dummy Authentication Provider
z/OSMF Authentication Provider#

The z/OSMF Authentication Provider allows API Gateway to authenticate with the z/OSMF service. The user needs z/OSMF access in order to authenticate.

Use the following properties of API Gateway to enable the z/OSMF Authentication Provider:

apiml.security.auth.provider: zosmfapiml.security.auth.zosmfServiceId: zosmf  # Replace me with the correct z/OSMF service id
Dummy Authentication Provider#

The Dummy Authentication Provider implements simple authentication for development purpose using dummy credentials (username: user, password user). The Dummy Authentication Provider allows API Gateway to run without authenticating with the z/OSMF service.

Use the following property of API Gateway to enable the Dummy Authentication Provider:

apiml.security.auth.provider: dummy

Authorization#

Authorization is a method used to determine access rights of an entity.

In the API ML, authorization is performed by the z/OS security manager (CA ACF2, IBM RACF, CA Top Secret). An authentication token is used as proof of valid authentication. The authorization checks, however, are always performed by the z/OS security manager.

JWT Token#

The JWT Secret that signs the JWT Token is an asymmetric private key that is generated during installation. You can find the JWT Secret, alias jwtsecret, in the PKCS12 keystore /keystore/localhost/localhost.keystore.p12. The public key necessary to read the JWT Secret is called from the keystore. For easy access, you can find the public key in the localhost.keystore.jwtsecret.pem directory. The JWT token is signed with the RS256 signature algorithm.

z/OSMF JSON Web Tokens Support#

Your z/OSMF instance can be enabled to support JWT tokens as described at Enabling JSON Web Token support. In this case, the Zowe API ML will use this JWT token and will not generate its own Zowe JWT token. All the authentication APIs, such as /api/v1/gateway/login and /api/v1/gateway/check will function in the same way as without z/OSMF JWT. The zowe-setup-certificates.sh stores the z/OSMF JWT public key to the localhost.keystore.jwtsecret.pem that can be used for JWT signature validation.

API ML truststore and keystore#

A keystore is a repository of security certificates consisting of either authorization certificates or public key certificates with corresponding private keys (PK), used in TLS encryption. A keystore can be stored in Java specific format (JKS) or use the standard format (PKCS12). The Zowe API ML uses PKCS12 to enable the keystores to be used by other technologies used in Zowe (Node.js).

The API ML local certificate authority (CA)

  • The API ML local CA contains a local CA certificate and a private key that needs to be securely stored
  • Used to sign certificates of services
  • The API ML local CA certificate is trusted by API services and clients

The API ML keystore

  • Server certificate of the Gateway (with PK). This can be signed by the local CA or an external CA
  • Server certificate of the Discovery Service (with PK). This can be signed by the local CA
  • Server certificate of the Catalog (with PK). This can be signed by the local CA
  • Private asymmetric key for the JWT token, alias jwtsecret. The public key is exported to the localhost.keystore.jwtsecret.cer directory.
  • The API ML keystore is used by API ML services

The API ML truststore

  • The API ML truststore contains a local CA public certificate
  • Contains an external CA public certificate (optional)
  • Can contain self-signed certificates of API Services that are not signed by the local or external CA
  • Used by API ML services

Zowe core services

  • Services can use the same keystore and truststore as APIML for simpler installation and management
  • Alternatively, services can have individual stores for higher security

API service keystore (for each service)

  • Contains a server and client certificate signed by the local CA

API service truststore (for each service)

  • (Optional) Contains a local CA and external CA certificates

Client certificates

  • A client certificate is a certificate that is used for validation of the HTTPS client. The client certificate of a Discovery Service client can be the same certificate as the server certificate of the services which the Discovery Service client uses.

Discovery Service authentication#

There are several authentication mechanisms, depending on the desired endpoint, as described by the following matrix:

EndpointAuthentication methodNote
UI (eureka homepage)basic auth(MF), tokensee note about mainframe authentication
application/**basic auth(MF), tokensee note about mainframe authentication
application/health, application/infonone
eureka/**client certificateAllows for the other services to register without mainframe credentials or token. The certificate is stored in the keystore/localhost/localhost.keystore.p12 keystore.
discovery/**certificate, basic auth(MF), tokensee note about mainframe authentication

Note: Some endpoints are protected by mainframe authentication. The authentication function is provided by the API Gateway. This functionality is not available until the Gateway registers itself to the Discovery Service.

Since the Discovery Service uses HTTPS, your client also requires verification of the validity of its certificate. Verification is performed by trusting the local CA certificate stored in keystore/local_ca/localca.cer.

Some utilities including HTTPie require the certificate to be in PEM format. The exported certificate in .pem format is located here: keystore/localhost/localhost.pem.

The following example shows HTTPie command to access the Discovery Service endpoint for listing registered services and provides the client certificate:

http --cert=keystore/localhost/localhost.pem --verify=false -j GET https://localhost:10011/eureka/apps/

Setting ciphers for API ML services#

You can override ciphers that are used by the HTTPS servers in API ML services by configuring properties of the Gateway, Discovery Service, and API Catalog.

Note: You do not need to rebuild JAR files when you override the default values in shell scripts.

The application.yml file contains the default value for each service, and can be found here. The default configuration is packed in .jar files. On z/OS, you can override the default configuration in $ZOWE_ROOT_DIR/components/api-mediation/bin/start.sh. Add the launch parameter of the shell script to set a cipher:

-Dapiml.security.ciphers=<cipher-list>

On localhost, you can override the default configuration in config/local/gateway-service.yml (including other YAML files for development purposes).

The following list shows the default ciphers. API ML services use the following cipher order:

Note: Ensure that the version of Java you use is compatible with the default cipherset.

   TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,   TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,   TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,   TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384

Only IANA ciphers names are supported. For more information, see Cipher Suites or List of Ciphers.

Certificate management in Zowe API Mediation Layer#

Running on localhost#

How to start API ML on localhost with full HTTPS#

The https://github.com/zowe/api-layer repository already contains pre-generated certificates that can be used to start API ML with HTTPS on your computer. The certificates are not trusted by your browser so you can either ignore the security warning or generate your own certificates and add them to the truststore of your browser or system.

The certificates are described in more detail in the TLS Certificates for localhost.

Certificate management script#

Zowe API Mediation Layer provides a script that can be used on Windows, Mac, Linux, and z/OS to generate a certificate and keystore for the local CA, API Mediation Layer, and services.

This script is stored in scripts/apiml_cm.sh. It is a UNIX shell script that can be executed by Bash or z/OS Shell. For Windows, install Bash by going to the following link: cmder.

Generate certificates for localhost#

Use the following script in the root of the zowe-install-packaging repository to generate certificates for localhost:

bin/apiml_cm.sh --action setup

This script creates the certificates and keystore for the API Mediation Layer in your current workspace.

Generate a certificate for a new service on localhost#

To generate a certificate for a new service on localhost, see Generating certificate for a new service on localhost.

Add a service with an existing certificate to API ML on localhost#

The instructions are described at Trust certificates of other services.

Service registration to Discovery Service on localhost#

To register a new service to the Discovery Service using HTTPS, provide a valid client certificate that is trusted by the Discovery Service.

Zowe runtime on z/OS#

Certificates for z/OS installation from the Zowe PAX file#

Certificates for the API ML local CA and API ML service are automatically generated by installing the Zowe runtime on z/OS from the PAX file. Follow the instructions in Installing the Zowe runtime on z/OS.

These certificates are generated by the certificate management script zowe-setup-certificates.sh that is installed to $ZOWE_ROOT_DIR/bin/zowe-setup-certificates.sh. This script internally calls the apiml_cm.sh script.

$ZOWE_ROOT_DIR is the directory where you installed the Zowe runtime.

The certificates are generated to the directory $KEYSTORE_DIRECTORY that is defined in a customized $ZOWE_ROOT_DIR/bin/zowe-setup-certificates.env file.

API ML keystore and truststore:

  • $KEYSTORE_DIRECTORY/localhost/localhost.keystore.p12

    • used for the HTTPS servers
    • contains the APIML server certificate signed by the local CA and private key for the server

  • $KEYSTORE_DIRECTORY/localhost/localhost.truststore.p12

    • use to validate trust when communicating with services that are registered to the APIML
    • contains the root certificate of the local CA (not the server certificate)
    • contains the local CA public certificate
    • can contain additional certificate to trust services that are not signed by local CA

API ML keystores and truststores need be accessible by the user ID that executes the Zowe runtime.

Local CA:

  • $KEYSTORE_DIRECTORY/local_ca/localca.cer

    • public certificate of local CA

  • $KEYSTORE_DIRECTORY/local_ca/localca.keystore.p12

    • private key of the local CA

The local CA keystore is only accessible by the user that installs and manages the Zowe runtime.

Import the local CA certificate to your browser#

Trust in the API ML server is a necessary precondition to properly encrypt traffic between web browsers and REST API client applications. Ensure this trust through the installation of a Certificate Authority (CA) public certificate. By default, API ML creates a local CA. Import the CA public certificate to the truststore for REST API clients and to your browser. You can also import the certificate to your root certificate store.

Note: The public certificate in the PEM format is stored at $KEYSTORE_DIRECTORY/local_ca/localca.cer where $KEYSTORE_DIRECTORY is defined in a customized $ZOWE_ROOT_DIR/bin/zowe-setup-certificates.env file during an installation step that generates Zowe certificates.

The certificate is stored in UTF-8 encoding so you need to transfer it as a binary file. Since this is the certificate to be trusted by your browser, it is recommended to use a secure connection for transfer.

Follow these steps:

  1. Download the local CA certificate to your computer. Use one of the following methods to download the local CA certificate to your computer:

    • Use Zowe CLI (Recommended) Issue the following command:

    zowe zos-files download uss-file --binary $KEYSTORE_DIRECTORY/local_ca/localca.cer

    • Use sftp Issue the following command:
    sftp <system>get $KEYSTORE_DIRECTORY/local_ca/localca.cer

    To verify that the file has been transferred correctly, open the file. The following heading and closing should appear:

    -----BEGIN CERTIFICATE-----...-----END CERTIFICATE-----

  2. Import the certificate to your root certificate store and trust it.

    • For Windows Run the following command:

    certutil -enterprise -f -v -AddStore "Root" localca.cer

    Note: Ensure that you open the terminal as administrator. This will install the certificate to the Trusted Root Certification Authorities.

    • For macOS Run the following command:

    $ sudo security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain localca.cer

    • For Firefox You can manually import your root certificate via the Firefox settings, or force Firefox to use the Windows truststore:

    Note: Firefox uses its own certificate truststore.

    Create a new Javascript file firefox-windows-truststore.js at C:\Program Files (x86)\Mozilla Firefox\defaults\pref with the following content:

    /* Enable experimental Windows truststore support */pref("security.enterprise_roots.enabled", true);

Generate a keystore and truststore for a new service on z/OS#

You can generate a keystore and truststore for a new service by calling the apiml_cm.sh script in the directory with API Mediation Layer:

cd $ZOWE_ROOT_DIRbin/apiml_cm.sh --action new-service --service-alias <alias> --service-ext <ext> \--service-keystore <keystore_path> --service-truststore <truststore_path> \--service-dname <dname> --service-password <password> --service-validity <days> \--local-ca-filename $KEYSTORE_DIRECTORY/local_ca/localca

The service-alias is an unique string to identify the key entry. All keystore entries (key and trusted certificate entries) are accessed via unique aliases. Since the keystore will have only one certificate, you can omit this parameter and use the default value localhost.

The service-keystore is a repository of security certificates plus corresponding private keys. The <keystore_path> is the path excluding the extension to the keystore that will be generated. It can be an absolute path or a path relative to the current working directory. The key store is generated in PKCS12 format with .p12 extension. It should be path in an existing directory where your service expects the keystore.

Example: /opt/myservice/keystore/service.keystore.

The service-truststore contains certificates from other parties that you expect to communicate with, or from Certificate Authorities that you trust to identify other parties. The <truststore_path> is the path excluding the extension to the trust store that will be generated. It can be an absolute path or a path relative to the current working directory. The truststore is generated in PKCS12 format.

The service-ext specifies the X.509 extension that should be the Subject Alternate Name (SAN). The SAN contains host names that are used to access the service. You need specify the same hostname that is used by the service during API Mediation Layer registration.

Example: "SAN=dns:localhost.localdomain,dns:localhost,ip:127.0.0.1"

Note: For more information about SAN, see SAN or SubjectAlternativeName at Java Keytool - Common Options.

The service-dname is the X.509 Distinguished Name and is used to identify entities, such as those which are named by the subject and issuer (signer) fields of X.509 certificates.

Example: "CN=Zowe Service, OU=API Mediation Layer, O=Zowe Sample, L=Prague, S=Prague, C=CZ"

The service-validity is the number of days after until the certificate expires.

The service-password is the keystore password. The purpose of the password is the integrity check. The access protection for the keystore and keystore need to be achieved by making them accessible only by the ZOVESVR user ID and the system administrator.

The local-ca-filename is the path to the keystore that is used to sign your new certificate with the local CA private key. It should point to the $KEYSTORE_DIRECTORY/local_ca/localca where $KEYSTORE_DIRECTORY is defined in a customized $ZOWE_ROOT_DIR/bin/zowe-setup-certificates.env file during an installation step that generates Zowe certificates.

Add a service with an existing certificate to API ML on z/OS#

The API Mediation Layer requires validation of the certificate of each service that it accessed by the API Mediation Layer. The API Mediation Layer requires validation of the full certificate chain. Use one of the following methods:

  • Import the public certificate of the root CA that has signed the certificate of the service to the APIML truststore.

  • Ensure that your service has its own certificate. If it was signed by intermediate CA all intermediate CA certificates ensure that all certificates are in its keystore.

    Note: If the service does not provide intermediate CA certificates to the APIML then the validation fails. This can be circumvented by importing the intermediate CA certificates to the API ML truststore.

Import a public certificate to the APIML truststore by calling in the directory with API Mediation Layer:

cd $ZOWE_ROOT_DIRbin/apiml_cm.sh --action trust --certificate <path-to-certificate-in-PEM-format> --alias <alias>
Procedure if the service is not trusted#

If you access a service that is not trusted, for example, by issuing a REST API request to it:

http --verify=$KEYSTORE_DIRECTORY/local_ca/localca.cer GET https://<gatewayHost>:<port></port>/api/v1/<untrustedService>/greeting

You will receive a similar response:

    HTTP/1.1 502    Content-Type: application/json;charset=UTF-8
    {        "messages": [            {                "messageContent": "The certificate of the service accessed by HTTPS using URI '/api/v1/<untrustedService>/greeting' is not trusted by the API Gateway: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target",                "messageKey": "apiml.common.tlsError",                "messageNumber": "AML0105",                "messageType": "ERROR"            }        ]    }

The response has the HTTP status code 502 Bad Gateway and a JSON response in the standardized format for error messages. The message has key apiml.common.tlsError and the message number AML0105 and content that explains details about the message.

If you receive this message, import the certificate of your service or the CA that has signed it to the truststore of the API Mediation Layer as described above.

Security Service Client Library#

The security-service-client-spring library enables authentication and endpoint protection. The library relies on API ML Gateway to provide authentication and token validation, and consists of the following components:

  • org.zowe.apiml.security.common - Components that are necessary to build Spring security
  • org.zowe.apiml.security.client - Components that enables the security client and Gateway lookup

@EnableApimlAuth annotation#

Use @EnableApimlAuth annotation to enable the security client and integration of the security-service-client-spring library. The annotation handles necessary component scans, creates the GatewaySecurityService, and starts the Gateway lookup logic.

Gateway lookup logic#

Security client uses the GatewayClient Spring component to represent a Gateway instance. Lookup logic scans the embedded Discovery client and sets a Gateway instance to ‘Gateway Client’ after the Spring context starts. The scanning process happens asynchronously from the context start-up. The security client provides the authentication service once the Gateway is found. Lookup status can be retrieved by calling GatewayClient.isInitialized() method or listen for GatewayLookupCompleteEvent event, which gets published after the Gateway instance is found.

Useful classes#

The core class of the library is org.zowe.apiml.security.client.service.GatewaySecurityService, which provides a facility to perform login and to validate the jwt token. The GatewaySecurityService has the following methods:

  • login - Allows to login to the API Gateway with a username and password and retrieve the valid JWT token

  • query - Allows to verify the JWT token validity and return the JWT token data

    The following providers process authentication requests:

  • org.zowe.apiml.security.client.login.GatewayLoginProvider - Verifies the mainframe credentials

  • org.zowe.apiml.security.client.token.GatewayTokenProvider - Authenticates the JWT token

The library contains the following Spring security filters and handlers:

  • org.zowe.apiml.security.common.content.BasicContentFilter - Authenticates the credentials from the basic authorization header. The filter in the SecurityConfiguration class is used to secure content with basic authentication. The credentials are extracted from the request header and are passed to the GatewayLoginProvider, which calls the /login endpoint.
  • org.zowe.apiml.security.common.content.CookieContentFilter - Authenticates the JWT token that is stored in the cookie. This filter in a SecurityConfiguration is used to secure content with the JWT token stored in the cookie. The JWT token is extracted from the cookie and passed to the GatewayTokenProvider, which calls the /query endpoint.
  • SuccessfulLoginHandler - Handles the successful login
  • UnauthorizedHandler - Handles unauthorized access
  • BasicAuthUnauthorizedHandler - Handles unauthorized access in the case of basic authentication
  • FailedAuthenticationHandler - Handles authentication failure
  • ResourceAccessExceptionHandler - Handles exceptions related to accessing other services/resources, such as GatewayNotFoundException or ServiceNotAccessibleException
  • AuthExceptionHandler - Handles exceptions thrown during authentication process

For more information, see Api Catalog security configuration (Reference usage of the library), Spring Security Architecture and Security with Spring Tutorial.

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