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Cedar Specification

This repository contains the formalization of Cedar and infrastructure for performing differential randomized testing (DRT) between the formalization and Rust production implementation available in cedar.

You can learn more about our formalization efforts in the following blog posts:

• How we built Cedar with automated reasoning and differential testing
• Lean Into Verified Software Development

Repository Structure

• cedar-lean contains the Lean formalization of, and proofs about, Cedar.
• cedar-drt contains code for fuzzing, property-based testing, and differential testing of Cedar.
• cedar-policy-generators contains code for generating schemas, entities, policies, and requests using the arbitrary crate.

See the README in each directory for more information.

Build

Lean formalization and proofs

• Install Lean, following the instructions here.
• cd cedar-lean
• source ../cedar-drt/set_env_vars.sh (only required if running on AL2)
• lake update
• lake build Cedar

DRT framework

The simplest way to build our DRT framework is to use the included Dockerfile:

docker build . -t cedar_drt # ~10 minutes
docker run --rm -it cedar_drt

If you'd rather not use Docker, here are the full instructions for a local build:

• Install Lean, following the instructions above.
• Clone the cedar repository in the current (cedar-spec) repository.
• source cedar-drt/set_env_vars.sh
• cd cedar-lean && ../cedar-drt/build_lean_lib.sh
• cd ../cedar-drt && cargo build

The build has only been tested on Amazon Linux 2.

Run

To run DRT:

• Follow the build instructions above.
• If running locally, source ./set_env_vars.sh.
• cargo fuzz run -s none <target>.

List the available fuzz targets with cargo fuzz list. Available targets are described in the README in the cedar-drt directory. That README also explains how to debug build failures, and how to save DRT-generated tests.

Additional commands available with cargo fuzz help.

VSCode

To work with cedar-drt in VSCode, first configure two settings so that the rust analyzer plugin doesn't error when trying to find the Lean installation and so that it works properly in the fuzz crate. Add the following entries to your .vscode/settings.json. First run source set_env_vars.sh && echo $LEAN_LIB_DIR to get the correct value for LEAN_LIB_DIR.

{
    "rust-analyzer.linkedProjects": [
        "./cedar-drt/fuzz/Cargo.toml"
    ],
    "rust-analyzer.cargo.extraEnv": {
        "LEAN_LIB_DIR": <$LEAN_LIB_DIR as populated by set_env_vars.sh>
    }
}

See the cedar-lean README for some additional consideration when working with the Lean formalization.

Security

See CONTRIBUTING for more information.

License

This project is licensed under the Apache-2.0 License.