Authentication, Authorization and Accounting (AAA) Services

Overview

Authentication, Authorization and Accounting (AAA) is a term for a framework controlling access to resources, enforcing policies to use those resources and auditing their usage. These processes are the fundamental building blocks for effective network management and security.

Authentication provides a way of identifying a user, typically by having the user enter a valid user name and valid password before access is granted. The process of authentication is based on each user having a unique set of criteria for gaining access. The AAA framework compares a user’s authentication credentials with other user credentials stored in a database. If the credentials match, the user is granted access to the network. If the credentials don’t match, authentication fails and access is denied.

Authorization is the process of finding out what an authenticated user is allowed to do within the system, which tasks can do, which API can call, etc. The authorization process determines whether the user has the authority to perform such actions.

Accounting is the process of logging the activity of an authenticated user, for example, the amount of data a user has sent and/or received during a session, which APIs called, etc.

Terms And Definitions

AAA
Authentication, Authorization and Accounting.
Token
A claim of access to a group of resources on the controller.
Domain
A group of resources, direct or indirect, physical, logical, or virtual, for the purpose of access control.
User
A person who either owns or has access to a resource or group of resources on the controller.
Role
Opaque representation of a set of permissions, which is merely a unique string as admin or guest.
Credential
Proof of identity such as user name and password, OTP, biometrics, or others.
Client
A service or application that requires access to the controller.
Claim
A data set of validated assertions regarding a user, e.g. the role, domain, name, etc.
IdP
Identity Provider.

Quick Start

Building

Get the code:

git clone https://git.opendaylight.org/gerrit/aaa

Build it:

cd aaa && mvn clean install

Installing

AAA is automatically installed upon installation of odl-restconf, but you can install it yourself directly from the Karaf console through the following command:

feature:install odl-aaa-shiro

Pushing changes

The following are basic instructions to push your contributions to the project’s GIT repository:

git add .
git commit -s
# make changes, add change id, etc.
git commit --amend
git push ssh://{username}@git.opendaylight.org:29418/aaa.git HEAD:refs/for/master

AAA Framework implementations

Since Boron release, the OpenDaylight’s AAA services are based on the Apache Shiro Java Security Framework. The main configuration file for AAA is located at “etc/shiro.ini” relative to the OpenDaylight Karaf home directory.

Known limitations

The database (H2) used by ODL AAA Authentication store is not-cluster enabled. When deployed in a clustered environment each node needs to have its AAA user file synchronized using out of band means.

How to enable AAA

AAA is enabled through installing the odl-aaa-shiro feature. The vast majority of OpenDaylight’s northbound APIs (and all RESTCONF APIs) are protected by AAA by default when installing the +odl-restconf+ feature, since the odl-aaa-shiro is automatically installed as part of them.

How to disable AAA

Edit the “etc/shiro.ini” file and replace the following:

/** = authcBasic

with

/** = anon

Then, restart the Karaf process.

How application developers can leverage AAA to provide servlet security

In order to provide security to a servlet, add the following to the servlet’s web.xml file as the first filter definition:

<context-param>
  <param-name>shiroEnvironmentClass</param-name>
  <param-value>org.opendaylight.aaa.shiro.web.env.KarafIniWebEnvironment</param-value>
</context-param>

<listener>
    <listener-class>org.apache.shiro.web.env.EnvironmentLoaderListener</listener-class>
</listener>

<filter>
    <filter-name>ShiroFilter</filter-name>
    <filter-class>org.opendaylight.aaa.shiro.filters.AAAShiroFilter</filter-class>
</filter>

<filter-mapping>
    <filter-name>AAAShiroFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Note

It is very important to place this AAAShiroFilter as the first javax.servlet.Filter, as Jersey applies Filters in the order they appear within web.xml. Placing the AAAShiroFilter first ensures incoming HTTP/HTTPS requests have proper credentials before any other filtering is attempted.

AAA Realms

AAA plugin utilizes the Shiro Realms to support pluggable authentication & authorization schemes. There are two parent types of realms:

  • AuthenticatingRealm
    • Provides no Authorization capability.
    • Users authenticated through this type of realm are treated equally.
  • AuthorizingRealm
    • AuthorizingRealm is a more sophisticated AuthenticatingRealm, which provides the additional mechanisms to distinguish users based on roles.
    • Useful for applications in which roles determine allowed capabilities.

OpenDaylight contains five implementations:

  • TokenAuthRealm
    • An AuthorizingRealm built to bridge the Shiro-based AAA service with the h2-based AAA implementation.
    • Exposes a RESTful web service to manipulate IdM policy on a per-node basis. If identical AAA policy is desired across a cluster, the backing data store must be synchronized using an out of band method.
    • A python script located at “etc/idmtool” is included to help manipulate data contained in the TokenAuthRealm.
    • Enabled out of the box. This is the realm configured by default.
  • ODLJndiLdapRealm
    • An AuthorizingRealm built to extract identity information from IdM data contained on an LDAP server.
    • Extracts group information from LDAP, which is translated into OpenDaylight roles.
    • Useful when federating against an existing LDAP server, in which only certain types of users should have certain access privileges.
    • Disabled out of the box.
  • ODLJndiLdapRealmAuthNOnly
    • The same as ODLJndiLdapRealm, except without role extraction. Thus, all LDAP users have equal authentication and authorization rights.
    • Disabled out of the box.
  • ODLActiveDirectoryRealm
    • Wraps the generic ActiveDirectoryRealm provided by Shiro. This allows for enhanced logging as well as isolation of all realms in a single package, which enables easier import by consuming servlets.
    • Disabled out of the box.
  • KeystoneAuthRealm
    • This realm authenticates OpenDaylight users against the OpenStack’s Keystone server by using the Keystone’s Identity API v3 or later.
    • Disabled out of the box.

Note

More than one Realm implementation can be specified. Realms are attempted in order until authentication succeeds or all realm sources are exhausted. Edit the securityManager.realms = $tokenAuthRealm property in shiro.ini and add all the realms needed separated by commas.

TokenAuthRealm

How it works

The TokenAuthRealm is the default Authorization Realm deployed in OpenDaylight. TokenAuthRealm uses a direct authentication mechanism as shown in the following picture:

TokenAuthRealm direct authentication mechanism

TokenAuthRealm direct authentication mechanism

A user presents some credentials (e.g., username/password) directly to the OpenDaylight controller token endpoint /oauth2/token and receives an access token, which then can be used to access protected resources on the controller.

How to access the H2 database

The H2 database provides an optional front-end Web interface, which can be very useful for new users. From the KARAF_HOME directory, you can run the following command to enable the user interface:

java -cp ./data/cache/org.eclipse.osgi/bundles/217/1/.cp/h2-1.4.185.jar
    org.h2.tools.Server -trace -pg -web -webAllowOthers -baseDir `pwd`

You can navigate to the following and login via the browser:

http://{IP}:8082/

ODLJndiLdapRealm

How it works

LDAP integration is provided in order to externalize identity management. This configuration allows federation with an external LDAP server. The user’s OpenDaylight role parameters are mapped to corresponding LDAP attributes as specified by the groupRolesMap. Thus, an LDAP operator can provision attributes for LDAP users that support different OpenDaylight role structures.

ODLJndiLdapRealmAuthNOnly

How it works

This is useful for setups where all LDAP users are allowed equal access.

KeystoneAuthRealm

How it works

This realm authenticates OpenDaylight users against the OpenStack’s Keystone server. This realm uses the Keystone’s Identity API v3 or later.

KeystoneAuthRealm authentication mechanism

KeystoneAuthRealm authentication/authorization mechanism

As can shown on the above diagram, once configured, all the RESTCONF APIs calls will require sending user, password and optionally domain (1). Those credentials are used to authenticate the call against the Keystone server (2) and, if the authentication succeeds, the call will proceed to the MDSAL (3). The credentials must be provisioned in advance within the Keystone Server. The user and password are mandatory, while the domain is optional, in case it is not provided within the REST call, the realm will default to (Default), which is hard-coded. The default domain can be also configured through the shiro.ini file (see the AAA User Guide).

The protocol between the Controller and the Keystone Server (2) can be either HTTPS or HTTP. In order to use HTTPS the Keystone Server’s certificate must be exported and imported on the Controller (see the Certificate Management section).

Authorization Configuration

OpenDaylight supports two authorization engines at present, both of which are roughly similar in behavior:

  • Shiro-Based Authorization
  • MDSAL-Based Dynamic Authorization

Note

The preferred mechanism for configuring AAA Authentication is the MDSAL-Based Dynamic Authorization. Read the following section.

Shiro-Based Static Authorization

OpenDaylight AAA has support for Role Based Access Control (RBAC) based on the Apache Shiro permissions system. Configuration of the authorization system is done off-line; authorization currently cannot be configured after the controller is started. The Authorization provided by this mechanism is aimed towards supporting coarse-grained security policies, the MDSAL-Based mechanism allows for a more robust configuration capabilities. Shiro-based Authorization describes how to configure the Authentication feature in detail.

Note

The Shiro-Based Authorization that uses the shiro.ini URLs section to define roles requirements is deprecated and discouraged since the changes made to the file are only honored on a controller restart.

Shiro-Based Authorization is not cluster-aware, so the changes made on the shiro.ini file have to be replicated on every controller instance belonging to the cluster.

The URL patterns are matched relative to the Servlet context leaving room for ambiguity, since many endpoints may match (i.e., “/restconf/modules” and “/auth/modules” would both match a “/modules/**” rule).

MDSAL-Based Dynamic Authorization

The MDSAL-Based Dynamic authorization uses the MDSALDynamicAuthorizationFilter engine to restrict access to particular URL endpoint patterns. Users may define a list of policies that are insertion-ordered. Order matters for that list of policies, since the first matching policy is applied. This choice was made to emulate behavior of the Shiro-Based Authorization mechanism.

A policy is a key/value pair, where the key is a resource (i.e., a “URL pattern”) and the value is a list of permissions for the resource. The following describes the various elements of a policy:

  • Resource: the resource is a string URL pattern as outlined by Apache Shiro. For more information, see http://shiro.apache.org/web.html.
  • Description: an optional description of the URL endpoint and why it is being secured.
  • Permissions list: a list of permissions for a particular policy. If more than one permission exists in the permissions list they are evaluated using logical “OR”. A permission describes the prerequisites to perform HTTP operations on a particular endpoint. The following describes the various elements of a permission:
    • Role: the role required to access the target URL endpoint.
    • Actions list: a leaf-list of HTTP permissions that are allowed for a Subject possessing the required role.

This an example on how to limit access to the modules endpoint:

HTTP Operation:
put URL: /restconf/config/aaa:http-authorization/policies

headers: Content-Type: application/json Accept: application/json

body:
  { "aaa:policies":
    { "aaa:policies":
      [ { "aaa:resource": "/restconf/modules/**",
        "aaa:permissions": [ { "aaa:role": "admin",
                               "aaa:actions": [ "get",
                                                "post",
                                                "put",
                                                "patch",
                                                "delete"
                                              ]
                             }
                           ]
        }
      ]
    }
  }

The above example locks down access to the modules endpoint (and any URLS available past modules) to the “admin” role. Thus, an attempt from the OOB admin user will succeed with 2XX HTTP status code, while an attempt from the OOB user user will fail with HTTP status code 401, as the user user is not granted the “admin” role.

Accounting Configuration

Accounting is handled through the standard slf4j logging mechanisms used by the rest of OpenDaylight. Thus, one can control logging verbosity through manipulating the log levels for individual packages and classes directly through the Karaf console, JMX, or etc/org.ops4j.pax.logging.cfg. In normal operations, the default levels exposed do not provide much information about AAA services; this is due to the fact that logging can severely degrade performance.

All AAA logging is output to the standard karaf.log file. For debugging purposes (i.e., to enable maximum verbosity), issue the following command:

log:set TRACE org.opendaylight.aaa

Enable Successful/Unsuccessful Authentication Attempts Logging

By default, successful/unsuccessful authentication attempts are NOT logged. This is due to the fact that logging can severely decrease REST performance.

It is possible to add custom AuthenticationListener(s) to the Shiro-based configuration, allowing different ways to listen for successful/unsuccessful authentication attempts. Custom AuthenticationListener(s) must implement the org.apache.shiro.authc.AuthenticationListener interface.

Certificate Management

The Certificate Management Service is used to manage the keystores and certificates at the OpenDaylight distribution to easily provides the TLS communication.

The Certificate Management Service managing two keystores:

  1. OpenDaylight Keystore which holds the OpenDaylight distribution certificate self sign certificate or signed certificate from a root CA based on generated certificate request.
  2. Trust Keystore which holds all the network nodes certificates that shall to communicate with the OpenDaylight distribution through TLS communication.

The Certificate Management Service stores the keystores (OpenDaylight & Trust) as .jks files under configuration/ssl/ directory. Also the keystores could be stored at the MD-SAL datastore in case OpenDaylight distribution running at cluster environment. When the keystores are stored at MD-SAL, the Certificate Management Service rely on the Encryption-Service to encrypt the keystore data before storing it to MD-SAL and decrypted at runtime.

How to use the Certificate Management Service to manage the TLS communication

The following are the steps to configure the TLS communication within your feature or module:

  1. It is assumed that there exists an already created OpenDaylight distribution project following this guide.
  2. In the implementation bundle the following artifact must be added to its pom.xml file as dependency.
<dependency>
  <groupId>org.opendaylight.aaa</groupId>
  <artifactId>aaa-cert</artifactId>
  <version>0.5.0-SNAPSHOT</version>
</dependency>
  1. Using the provider class in the implementation bundle needs to define a variable holding the Certificate Manager Service as in the following example:
import org.opendaylight.aaa.cert.api.ICertificateManager;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;

public class UseCertManagerExampleProvider {
  private final DataBroker dataBroker;
  private final ICertificateManager caManager;

  public EncSrvExampleProvider(final DataBroker dataBroker, final ICertificateManager caManager) {
    this.dataBroker = dataBroker;
    this.caManager = caManager;
  }
  public SSLEngine createSSLEngine() {
    final SSLContext sslContext = caManager.getServerContext();
    if (sslContext != null) {
      final SSLEngine sslEngine = sslContext.createSSLEngine();
      sslEngine.setEnabledCipherSuites(caManager.getCipherSuites());
      // DO the Implementation
      return sslEngine;
    }
  }
  public void init() {
      // TODO
  }
  public void close() {
      // TODO
  }
}
  1. The Certificate Manager Service provides two main methods that are needed to establish the SSLEngine object, getServerContext() and getCipherSuites() as the above example shows. It also provides other methods such as getODLKeyStore() and getTrustKeyStore() that gives access to the OpenDaylight and Trust keystores.
  2. Now the ICertificateManager need to be passed as an argument to the UseCertManagerExampleProvider within the implementation bundle blueprint configuration. The following example shows how:
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
  xmlns:odl="http://opendaylight.org/xmlns/blueprint/v1.0.0"
  odl:use-default-for-reference-types="true">
  <reference id="dataBroker"
    interface="org.opendaylight.controller.md.sal.binding.api.DataBroker"
    odl:type="default" />
  <reference id="aaaCertificateManager"
    interface="org.opendaylight.aaa.cert.api.ICertificateManager"
    odl:type="default-certificate-manager" />
  <bean id="provider"
    class="org.opendaylight.UseCertManagerExample.impl.UseCertManagerExampleProvider"
    init-method="init" destroy-method="close">
    <argument ref="dataBroker" />
    <argument ref="aaaCertificateManager" />
  </bean>
</blueprint>
  1. After finishing the bundle implementation the feature module needs to be updated to include the aaa-cert feature in its feature bundle pom.xml file.
<properties>
  <aaa.version>0.5.0-SNAPSHOT</aaa.version>
</properties>
<dependency>
  <groupId>org.opendaylight.aaa</groupId>
  <artifactId>features-aaa</artifactId>
  <version>${aaa.version}</version>
  <classifier>features</classifier>
  <type>xml</type>
</dependency>
  1. Now, in the feature.xml file add the Certificate Manager Service feature and its repository.
<repository>mvn:org.opendaylight.aaa/features-aaa/{VERSION}/xml/features</repository>

The Certificate Manager Service feature can be included inside the implementation bundle feature as shown in the following example:

<feature name='odl-UseCertManagerExample' version='${project.version}'
  description='OpenDaylight :: UseCertManagerExample'>
  <feature version='${mdsal.version}'>odl-mdsal-broker</feature>
  <feature version='${aaa.version}'>odl-aaa-cert</feature>
  <bundle>mvn:org.opendaylight.UseCertManagerExample/UseCertManagerExample-impl/{VERSION}</bundle>
</feature>
  1. Now the project can be built and the OpenDaylight distribution started to continue with the configuration process. See the User Guide for more details.

Encryption Service

The AAA Encryption Service is used to encrypt the OpenDaylight users’ passwords and TLS communication certificates. This section shows how to use the AAA Encryption Service with an OpenDaylight distribution project to encrypt data.

  1. It is assumed that there exists an already created OpenDaylight distribution project following this guide.
  2. In the implementation bundle the following artifact must be added to its pom.xml file as dependency.
<dependency>
  <groupId>org.opendaylight.aaa</groupId>
  <artifactId>aaa-encrypt-service</artifactId>
  <version>0.5.0-SNAPSHOT</version>
</dependency>
  1. Using the provider class in the implementation bundle needs to define a variable holding the Encryption Service as in the following example:
import org.opendaylight.aaa.encrypt.AAAEncryptionService;
import org.opendaylight.controller.md.sal.binding.api.DataBroker;

public class EncSrvExampleProvider {
private final DataBroker dataBroker;
  private final AAAEncryptionService encryService;

  public EncSrvExampleProvider(final DataBroker dataBroker, final AAAEncryptionService encryService) {
    this.dataBroker = dataBroker;
    this.encryService = encryService;
  }
  public void init() {
    // TODO
  }
  public void close() {
    // TODO
  }
}

The AAAEncryptionService can be used to encrypt and decrypt any data based on project’s needs.

  1. Now the AAAEncryptionService needs to be passed as an argument to the EncSrvExampleProvider within the implementation bundle blueprint configuration. The following example shows how:
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
  xmlns:odl="http://opendaylight.org/xmlns/blueprint/v1.0.0"
  odl:use-default-for-reference-types="true">
  <reference id="dataBroker"
    interface="org.opendaylight.controller.md.sal.binding.api.DataBroker"
    odl:type="default" />
  <reference id="encryService" interface="org.opendaylight.aaa.encrypt.AAAEncryptionService"/>
  <bean id="provider"
    class="org.opendaylight.EncSrvExample.impl.EncSrvExampleProvider"
    init-method="init" destroy-method="close">
    <argument ref="dataBroker" />
    <argument ref="encryService" />
  </bean>
</blueprint>
  1. After finishing the bundle implementation the feature module needs to be updated to include the aaa-encryption-service feature in its feature bundle pom.xml file.
<dependency>
  <groupId>org.opendaylight.aaa</groupId>
  <artifactId>features-aaa</artifactId>
  <version>${aaa.version}</version>
  <classifier>features</classifier>
  <type>xml</type>
</dependency>

It is also necessary to add the aaa.version in the properties section:

<properties>
  <aaa.version>0.5.0-SNAPSHOT</aaa.version>
</properties>
  1. Now, in the feature.xml file add the Encryption Service feature and its repository.
<repository>mvn:org.opendaylight.aaa/features-aaa/{VERSION}/xml/features</repository>

The Encryption Service feature can be included inside the implementation bundle feature as shown in the following example:

<feature name='odl-EncSrvExample' version='${project.version}' description='OpenDaylight :: EncSrvExample'>
  <feature version='${mdsal.version}'>odl-mdsal-broker</feature>
  <feature version='${aaa.version}'>odl-aaa-encryption-service</feature>
  <feature version='${project.version}'>odl-EncSrvExample-api</feature>
  <bundle>mvn:org.opendaylight.EncSrvExample/EncSrvExample-impl/{VERSION}</bundle>
</feature>
  1. Now the project can be built and the OpenDaylight distribution started to continue with the configuration process. See the User Guide for more details.