Pin actions to a full length commit SHA

[naveensrinivasan]

• Pinned actions by SHA https://github.com/ossf/scorecard/blob/main/docs/checks.md#pinned-dependencies

Pin actions to a full length commit SHA

Pinning an action to a full length commit SHA is currently the only way to use an action as an immutable release. Pinning to a particular SHA helps mitigate the risk of a bad actor adding a backdoor to the action's repository, as they would need to generate a SHA-1 collision for a valid Git object payload.

https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions#using-third-party-actions

How do I validate these pinned actions?

Also, dependabot supports upgrading based on SHA. ossf/scorecard#1700

GitHub's own repository pin's their checkout actions by SHA and doesn't use the version tag
https://github.com/github/docs/blob/ea7f218c91ecbae9a700a8702b51a7d2736e0d2c/.github/workflows/docs-review-collect.yml#L23

Signed-off-by: naveensrinivasan 172697+naveensrinivasan@users.noreply.github.com

[Jason3S]

@naveensrinivasan,

Thank you for working on improving the security of the repository. I was unaware of the permission settings. I knew something had changed on GitHub, but had not had the time to follow up. Your previous diff showed me what needed to be done.

I understand the security risk of using release tags (they can be changed) and at the same time SHA's are very difficult to maintain. I hope github provides a better solution, linking directly to repositories is not idea. There is no vetting process.