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sigstore-ansible

Automation to deploy the sigstore ecosystem on RHEL

⚠️ The contents of this repository are a Work in Progress.

Overview

The automation within this repository establishes the components of the Sigstore project within a single Red Hat Enterprise Linux (RHEL) machine using a standalone containerized deployment. Containers are spawned using Kubernetes based manifests using podman kube play.

The following Sigstore components are deployed as part of this architecture:

• Rekor
  • Trillian
• Fulcio
• Certificate Log

An NGINX frontend is placed as an entrypoint to the various backend components. Communication is secured via a set of self-signed certificates that are generated at runtime.

Utilize the steps below to understand how to setup and execute the provisioning.

Prerequisites

A RHEL 8.8+ or a RHEL 9.2+ server should be used to run the RHTAS components.

Ansible must be installed and configured on a control node that will be used to perform the automation.

NOTE: Future improvements will make use of an Execution environment

Perform the following steps to prepare the control node for execution.

Dependencies

Install the required Ansible collections by executing the following

ansible-galaxy collection install -r requirements.yml

Inventory

Populate the sigstore group within the inventory file with details related to the target host.

OIDC provider

An installation of Keycloak must be provided to allow for integration with containerized RHTAS.

Ingress

The automation deploys and configures a software load balancer as a central point of ingress. Multiple hostnames underneath a base hostname are configured and include the following hostnames:

• https://rekor.<base_hostname>
• https://fulcio.<base_hostname>
• https://tuf.<base_hostname>

Each of these hostnames must be configured in DNS to resolve to the target machine. The base_hostname parameter must be provided when executing the provisining. To configure hostnames in DNS, edit /etc/hosts with the following content:

<REMOTE_IP_ADDRESS> fulcio.<base_hostname> fulcio
<REMOTE_IP_ADDRESS> rekor.<base_hostname> rekor
<REMOTE_IP_ADDRESS> tuf.<base_hostname> tuf

Cosign

cosign is used as part of testing and validating the setup and configuration. It is an optional install if there is not a desire to perform the validation as described below.

Provision

Execute the following commands to execute the automation:

NOTE: Please provide credentials to authenticate to registry.redhat.io. https://access.redhat.com/RegistryAuthentication

# Run the playbook from your local system
ansible-playbook -i inventory playbooks/install.yml -e registry_username='REGISTRY.REDHAT.IO_USERNAME' -e registry_password='REGISTRY.REDHAT.IO_PASSWORD' base_hostname=example.com'

Add the root CA that was created to your local truststore.

The certificate can be downloaded from the browser Certificate Viewer by navigating to https://rekor.<base_domain>. Download the root certiicate that issued the rekor certificate. In Red Hat based systems, the following commands will add a CA to the system truststore.

$ sudo openssl x509 -in ~/Downloads/root-cert-from-browser -out sigstore-ca.pem --outform PEM
$ sudo mv sigstore-ca.pem /etc/pki/ca-trust/source/anchors/
$ sudo update-ca-trust

Signing a Container

Utilize the following steps to sign a container that has been published to an OCI registry

1. Export the following environment variables substituting base_hostname with the value used as part of the provisioning

export KEYCLOAK_REALM=sigstore
export BASE_HOSTNAME=<base_hostname>
export FULCIO_URL=https://fulcio.$BASE_HOSTNAME
export KEYCLOAK_URL=https://keycloak.$BASE_HOSTNAME
export REKOR_URL=https://rekor.$BASE_HOSTNAME
export TUF_URL=https://tuf.$BASE_HOSTNAME
export KEYCLOAK_OIDC_ISSUER=$KEYCLOAK_URL/realms/$KEYCLOAK_REALM

2. Initialize the TUF roots

cosign initialize --mirror=$TUF_URL --root=$TUF_URL/root.json

Note: If you have used cosign previously, you may need to delete the ~/.sigstore directory

3. Sign the desired container

cosign sign -y --fulcio-url=$FULCIO_URL --rekor-url=$REKOR_URL --oidc-issuer=$KEYCLOAK_OIDC_ISSUER  <image>

Authenticate with the Keycloak instance using the desired credentials.

4. Verify the signed image

Refer to this example that verifies an image signed with email identity [email protected] and issuer https://github.com/login/oauth.

cosign verify \
--rekor-url=$REKOR_URL \
--certificate-identity-regexp sigstore-user \
--certificate-oidc-issuer-regexp keycloak  \
<image>

If the signature verification did not result in an error, the deployment of Sigstore was successful!

Testing

This repository contains GitHub actions that will test PRs that come in by creating an instance of RHEL 9 and deploying RHTAS then testing to ensure the image can be signed and verified.

Feedback

Any and all feedback is welcomed. Submit an Issue or Pull Request as desired.