Sign container images with cosign for supply-chain security

[goelakash]

The OpenSSF Scorecard flags the Signed-Releases check because published Docker images are not cryptographically signed.

Signing images with cosign (keyless, via GitHub OIDC) would allow consumers to verify image provenance (e.g. Chainguard Images uses sigstore/cosign-installer in their release workflow).

Related to #2428

[theamitmehra]

Hey, I'd love to take a stab at this. Would this be a good first contribution, or is there anything I should know about the current publish workflow before diving in?

[mathbunnyru]

Hey, I'd love to take a stab at this. Would this be a good first contribution, or is there anything I should know about the current publish workflow before diving in?

Unfortunately, I don't have any experience with signing Docker images, so I can't help here.

What I would definitely like to avoid is creating images that are not inherited from each other in terms of Docker layers.
For example, if you already pulled the latest minimal-notebook, all the layers for docker-stacks-foundation and base-notebook should be available locally, and it shouldn't repull the whole images.

This property is true right now, even for images created in PRs, because we:

• upload an image: https://github.com/jupyter/docker-stacks/blob/main/.github/workflows/docker-build-test-upload.yml#L140
• and then pull it when building any image inherited from that one: https://github.com/jupyter/docker-stacks/blob/main/.github/actions/load-image/action.yml

Signing might not change this property at all, but it's definitely something to be aware of.

[mathbunnyru]

@theamitmehra are you still planning to work on this?
(I don't plan to work on it personally, just asking if someone might want to work on this too)

[theamitmehra]

Yes, I'm still interested! I'll start working on a draft PR soon

[mathbunnyru]

Yes, I'm still interested! I'll start working on a draft PR soon

Perfect, thanks!

[theamitmehra]

Yes, the merged multi-platform manifest should be signed too since that's what most users pull. I'll update the PR to include docker-tag-push-merge.yml as well.

[mathbunnyru]

Yes, the merged multi-platform manifest should be signed too since that's what most users pull. I'll update the PR to include docker-tag-push-merge.yml as well.

I think you meant this comment to be in PR :)

[theamitmehra]

oh so sorry, i had both these tabs open, and commented here. my bad

[mathbunnyru]

This has been reverted - it would require better testing before being merged