Security

Authentication & Authorization

In order to control access the FactCast Server supports a very basic way of defining which client is allowed to do what. The security feature is enabled by default, but can be disabled (for integration tests for example) by setting factcast.security.enabled to false.

In order to make use of the security features, a Bean of type FactCastAccessConfig must be defined. This is done either by providing one in your FactCast Server’s context, or by using the dead-simple approach to put a factcast-access.json on the root of your classpath or at /config/ to deserialize it from there.

Example below.

Now, that you’ve defined the access configuration, you also need to define the secrets for each account. Again, you can do that programmatically by providing a FactCastSecretsProperties, or by defining a property for each account like this:

factcast.access.secrets.brain=world
factcast.access.secrets.pinky=narf
factcast.access.secrets.snowball=grim

The catch with this simple approach of course is, that credentials are stored in plaintext in the server’s classpath, but remember it is just a dead-simple approach to get you started. Nobody says, that you cannot provide this information with a layer of your docker container, pull it from the AWS Parameter Store etc…

If FactCast misses a secret for a configured account on startup, it will stop immediately. On the other hand, if there is a secret defined for a non-existing account, this is just logged (WARNING-Level).

The contents of factcast-access.json might look like:

{
	"accounts": [
		{
			"id": "brain",
			"roles": ["anything"]
		},
		{
			"id": "pinky",
			"roles": ["anything", "limited"]
		},
		{
			"id": "snowball",
			"roles": ["readOnlyWithoutAudit"]
		}
	],
	"roles": [
		{
			"id": "anything",
			"read": {
				"include": ["*"]
			},
			"write": {
				"include": ["*"]
			}
		},
		{
			"id": "limited",
			"read": {
				"include": ["*"],
				"exclude": ["secret"]
			},
			"write": {
				"exclude": ["audit*"]
			}
		},
		{
			"id": "readOnlyWithoutAudit",
			"read": {
				"include": ["*"],
				"exclude": ["audit*", "secret"]
			},
			"write": {
				"exclude": ["*"]
			}
		}
	]
}

Where pinky & brain are authorized to use the full FactStore’s functionality (with ‘pinky’ not being able to write to namespaces that start with ‘audit’) whereas snowball can only read everything but ‘audit’-namespaces, but not write anything.

In case of conflicting information:

• explicit wins over implicit
• exclude wins over include

Note, there is no fancy wildcard handling other than a trailing ‘*’.

see module examples/factcast-example-server-basicauth for an example

Using BasicAuth from a client

From a client’s perspective, all you need to do is to provide credentials. Once the credentials are configured, they are used on every request in a Basic-Auth fashion (added header to request).

factcast.grpc.client.user and factcast.grpc.client.password are the properties to set.

You can always use environment variables or a -D switch in order to inject the credentials.

see module examples/factcast-example-client-basicauth for an example

Customizing Credential Loading

If you dont want to configure your passwords via properties, you can provide either a custom FactCastSecretProperties bean or an implementation of a UserDetailsService. That’s a simple interface coming from Spring Security which provides a mapping method from username to user. In our case we have to return a FactCastUser.

If you want to externalize secret loading but want to keep the factcast-access.json file for managing authorization an implementation of such a UserDetailsService could look like this:

@Bean
UserDetailsService userDetailsService(FactCastAccessConfiguration cc, PasswordEncoder passwordEncoder) {
    return username -> {
        // fetching account info from fact-access.json
        Optional<FactCastAccount> account = cc.findAccountById(username);

        // your way to fetch the user + password
        User user = loadUserByName(username);

        return account
            .map(acc -> new FactCastUser(acc, passwordEncoder.encode(user.getPassword())))
            .orElseThrow(() -> new UsernameNotFoundException(username));
    };
}