OpenRemote Groovy Sandbox

This repository is an OpenRemote-maintained fork of craftercms/groovy-sandbox, which itself derives from the original jenkinsci/groovy-sandbox project.

The library provides a Groovy compile-time transformer that rewrites script operations so they can be intercepted by application code. OpenRemote uses this as part of its Groovy rules hardening work.

The Java package name remains org.kohsuke.groovy.sandbox for compatibility with existing consumers, including OpenRemote code that imports classes such as org.kohsuke.groovy.sandbox.SandboxTransformer.

Fork Status

Current baseline:

• Forked from craftercms/groovy-sandbox develop at commit 97360e2.
• Maven coordinates changed to org.openremote:groovy-sandbox.
• Java package names kept unchanged for API compatibility.
• Java 21 and Groovy 5 are the current build targets.

Relevant security and correctness fixes from jenkinsci/groovy-sandbox should be documented here as they are manually ported into this fork. This fork should not blindly cherry-pick Jenkins build, release, plugin, or CI metadata.

Maven Coordinates

The Maven coordinates for this fork are:

<dependency>
    <groupId>org.openremote</groupId>
    <artifactId>groovy-sandbox</artifactId>
    <version>1.27.6-SNAPSHOT</version>
</dependency>

Publishing targets are intentionally not configured in this repository yet. Snapshots should be published only after OpenRemote has validated the fork against its own rules tests.

Build

Requirements:

• Java 21
• Maven 3.9 or newer

Run the test suite:

mvn -B test

Build the jar, test jar, and sources jar:

mvn -B package

The current POM pins Groovy to 5.0.6.

Basic Usage

Add SandboxTransformer to a CompilerConfiguration before compiling the Groovy script:

def cc = new CompilerConfiguration()
cc.addCompilationCustomizers(new SandboxTransformer())

def shell = new GroovyShell(new Binding(), cc)

Register an interceptor around script execution:

def sandbox = new GroovyValueFilter() {
    Object filter(Object value) {
        throw new SecurityException("Denied")
    }
}

sandbox.register()
try {
    shell.evaluate("println 'hello'")
} finally {
    sandbox.unregister()
}

See src/test/groovy/org/kohsuke/groovy/sandbox/robot for an allowlist-style example that permits selected application objects and rejects everything else.

Security Model

This library is defense in depth. It is not a complete JVM security boundary by itself.

Important constraints:

• Interceptors are thread-specific. Scripts must not be allowed to create or control threads or executor services that run outside the registered interceptor context.
• Use an allowlist model. Blocking a known-dangerous method is not enough because another allowed method may call it internally.
• Reflection, class loading, process execution, filesystem access, networking, and Groovy dynamic hooks need explicit policy decisions.
• OpenRemote should combine this transformer with compiler restrictions, narrow rule DSL facades, and runtime containment before enabling untrusted Groovy authoring.

For OpenRemote, this means non-superuser Groovy rule editing should remain disabled until this fork has a tested allowlist and OpenRemote has additional runtime containment.

License And Attribution

This OpenRemote fork distribution is licensed under the GNU Affero General Public License version 3 or later. See LICENSE.md.

The upstream-origin code remains covered by the MIT License. The MIT license text and original upstream copyright notice are preserved in LICENSE-MIT.md. See NOTICE.md for fork attribution and OpenRemote contribution licensing notes.

OpenRemote-specific changes should be documented in this repository without removing existing Kohsuke Kawaguchi, CloudBees, Jenkins, CrafterCMS, or other upstream contributor attribution.