Data Filtering on Spring Data with Open Policy Agent

opa-datafilter-jpa-spring-boot-starter

opa-datafilter-mongo-spring-boot-starter

Pre-requisites

The blog posts below explain enough of the What and Why!

• Read about Open Policy Agent Partial (OPA) Evaluation blog post here
• Read the sample use case, Write Policy in OPA. Enforce Policy in SQL
• The OPA Compile API

The Libraries

opa-datafilter-jpa-spring-boot-starter and opa-datafilter-mongo-spring-boot-starter are Spring Boot libraries which can be used together with Spring Data JPA and Spring Data MongoDB, respectively, to enforce authorization on data by filtering using OPA Partial Evaluation feature. When a user wants to access a protected collection of resources, the libraries create a partial request object which contains about the user and the operation a user wants to perform. The partial request object is sent to the OPA compile API. OPA evaluates the partial request and returns a new and simplified policy that can be evaluated more efficiently than the original policy. These libraries convert the new policy, the OPA compile API response, into SQL or MongoDB queries. A filtered collection of data is returned to the user which a user is allowed to see.

Open Policy Agent Supported Version

• Tested in OPA v0.25.0 and below

Supported Spring Data findAll methods

The libraries override Spring Data methods:

• findAll()
• findAll(Sort sort)
• findAll(Pageable pageable)

Installation and Usage

See each individual folder for installation and usage instructions.

• opa-datafilter-jpa-spring-boot-starter
• opa-datafilter-mongo-spring-boot-starter

Query Verification

To verify how the SQL or MongoDB query looks like, use the opa-datafilter-datafilter-query-service or the the docker image, opa-query-service. The service provides an API for translating OPA partial request object into a SQL or MongoDB query.

Configurations

Properties	Type	Default Value	Description	Required
opa.authorization.url	String	http://localhost:8181/v1/compile	The OPA compile API endpoint.	Yes
opa.authorization.data-filter-enabled	Boolean	true	Enable OPA data filter authorization	No
opa.partial-request.log-partial-request	Boolean	false	Log the partial request json which was sent to OPA on std out for debugging	No
opa.partial-request.query	String		The query to partially evaluate and compile	Yes
opa.partial-request.unknowns	Set		The terms to treat as unknown during partial evaluation	Yes
opa.partial-request.user-attribute-to-http-header-map	Map<String, String>		The mapping of user attribute to Http Header. These mappings will be added as subject attributes in the input of the partial request. The key will be set as the attribute name and the value of the Http header will be set as the value of the key.	No

Example Spring Boot Applications

See example Spring Boot microservice applications that use these libraries:

• opa-datafilter-jpa-demo
• opa-datafilter-mongo-demo

The Partial Request

Default Partial Request

When the findAll method is invoked from OpaDataFilterRepository interface, a partial request object is sent to the OPA compile API endpoint. The default partial request is the following:

{
   "query": "data.petclinic.authz.allow = true",
   "input": {
   	"path": ["pets"],
   	"method": "GET",
   	"subject": {
   		"user": "alice",
   		"jwt": "<jwt token>"
   	}
   },
   "unknowns": ["data.pets"]
}

where:

• query - is the value of opa.partial-request.query from the configuration property.
• input - by default http servlet path and method are added as path and method respectively. The subject (the current user) by default has user property which is derived from Authorization Basic header if it exists and jwt property from the Authorization Bearer header if it exists.
• unknowns - the value of opa.partial-request.unknowns from the configuration property.

Adding Attributes to the Default Partial Request

It is possible to add attributes to the subject property of the default partial request. This can be done by mapping the attribute to the Http header using a configuration opa.partial-request.user-attribute-to-http-header-map. For example:

opa:
  partial-request:
    log-partial-request: true
    user-attribute-to-http-header-map:
      organization: X-ORG-HEADER

The organization is key of the attribute and the value of the X-ORG-HEADER http header is the value of the key. The partial request will look like the following:

{
	"query": "data.petclinic.authz.allow = true",
	"input": {
		"path": ["pets"],
		"method": "GET",
		"subject": {
			"user": "alice",
			"attributes": {
				"organization": "SOMA"
			}
		}
	},
	"unknowns": ["data.pets"]
}

Contributors

• Joffry Ferrater
• Reihmon Estremos
• Jolly Jae Ompod
• Alvin Difuntorum