Introduction to SLSA

SLSA is a framework with individual levels that software producers can work towards to make their software more secure, and consumers can make decisions based on the software package’s security posture.

What does this mean in practice? Adoptium meets level 1 and 2 of the SLSA v0.1 specification for the production of Eclipse Temurin and the Eclipse Temurin Project page now has a badge to indicate this.

SLSA Level 1

Level 1 means that the build process is full scripted and automated. We are now producing and distributing Software Bill Of Material (SBOM) documents which are shipped alongside our release builds. We have been compliant with level 1 for some time: The level 1 requirements are:

• Build - scripted build: Our build steps are defined completely by the Jenkins pipelines from the ci-jenkins-pipelines repository and the underlying scripts run on the build machines from the temurin-build repository - starting at make-adopt-build-farm.sh

• Provenance - available: We create an SBOM in OWASP CycloneDX format along with our releases which contains all of the information about how the builds are produced, which should allow someone to rebuild if required for any reason. This includes the full set of parameters which we use to the makejdk_any_platform.sh script (invoked from make-adopt-build-farm.sh), the source repository tags (scmRef) which was used by the build process to produce the builds, the output from the openjdk configure invocation and various other pieces of information. We are continually evolving the specific details which we include in the SBOM. If you want to join in the discussion on the content, you can find the conversation in temurin-build#3013 or talk to us in the #secure-dev slack channel in the Adoptium workspace.

SLSA Level 2

Level 2 adds in additional requirements to provide some tamper resistance of the build process, including having all of our code version controlled. We achieve this through our use of GitHub for both the OpenJDK product code and the code that runs the build and distribution processes through our Jenkins CI server. The requirements here are:

• Source - Version controlled. All of our source code is stored in GitHub in the jdkXX repositories such as jdk17u, which we mirror from the openjdk project. These are version controlled and have tags for each release which we build from. Contributors agree to the rules of the Eclipse Contributor Agreement (ECA)

• Build - Build service. All of the build steps are run using our Jenkins build service (https://ci.adoptium.net) which is used to perform the builds, generate the SBOMs, and build the installers where applicable. The output from the builds are then posted into GitHub release repositories named as temurinXX-binaries (e.g. temurin17-binaries and also exposed via our API and download pages.

• Provenance - Authenticated. We sign the SBOMs for the latest set of releases to guarantee their authenticity.

• Provenance - service generated. The GPG signatures for the binary are generated as an integral part of the build process for the binaries and will be done in the same way for the signing of the SBOMs - the current SBOM signing was done retrospectively in our Jenkins instance. The Jenkins instance hosts the private keys from the Eclipse Foundation which are used to perform the signature generation.

Next steps for the project

Are we finished? Absolutely not! We are continuing to work towards achieving the higher levels of SLSA and have already achieved many of the requirements of higher levels. But for now, we are proud to be able to claim full compliance with SLSA level 2.

We are currently tracking forward progress to meeting the higher level requirements at adoptium#160. We already meet some of the requirements of higher levels - in some cases there are differences in the criteria which we meet on different platforms. For example, we have worked to make our build process reproducible and on Linux, Windows and macOS for JDK17 (LTS) and JDK19+ we have created and shipped binary reproducible builds with the exception of some instances where the class data sharing archive is not identical.

We are working towards implementing the other parts of the higher SLSA levels which we do not yet meet. Some of these, such as the Ephemeral environment requirement, may take some time to achieve on all platforms and you can follow the current status in the SLSA tracking issue, or on the SLSA page on our site.