New tool: cosign

[rh-hemartin]

Tool name

Cosign

What is the tool used for?

Some tools are starting to recommend users to verify their checksum lists before using the checksums to validate artifacts themselves. cosign is being adopted for this usage so it will be useful to have it included within Renovate's -full image. Users of Renovate hooked scripts to update checksum SHAs before, now they would verify the checksum list files with cosign after download and then modify the checksum at the same time as the version. For some example of this see the Tirith Install Script, or cosign installation verification instructions (they don't use cosign to verify cosign, this would be the process Renovate would use to install cosign in the first place).

Tool scope

• Runtime only (CLI / binary)
• Full development stack (headers, SDK, compiler)

Supported version range

=v3.1.2

Key commands that must work

cosign verify-blob

Uninstall strategy

rm -rf /usr/local/bin/cosign

License of the tool (and any pre‑built binaries)

https://github.com/sigstore/cosign/blob/main/LICENSE

Minimal Dockerfile snippet (optional but highly encouraged)

FROM ghcr.io/renovatebot/renovate:39

# When bumping COSIGN_VERSION, update COSIGN_SHA256 to match. Verify the
# checksum following https://docs.sigstore.dev/cosign/system_config/installation/#verifying-cosign-releases
ARG COSIGN_VERSION=v3.1.2
ARG COSIGN_SHA256=f7622ed3cf22e55e1ae6377c080979ff77a22da9981c11df222a2e444991e7cf

USER root

RUN curl -fsSL -o /usr/local/bin/cosign \
      "https://github.com/sigstore/cosign/releases/download/${COSIGN_VERSION}/cosign-linux-amd64" && \
    echo "${COSIGN_SHA256}  /usr/local/bin/cosign" | sha256sum -c && \
    chmod +x /usr/local/bin/cosign

USER ubuntu

Suggested tests

RUN cosign version

Any other relevant information

No response