gh-action-sigstore-python

A GitHub Action that uses sigstore-python to generate Sigstore signatures.

Index

• Usage
• Configuration
  • ⚠️ Internal options ⚠️
• Licensing
• Code of Conduct

Usage

Simply add sigstore/gh-action-sigstore-python to one of your workflows:

jobs:
  selftest:
    runs-on: ubuntu-latest
    permissions:
      id-token: write
    steps:
      - uses: actions/checkout@v3
      - name: install
        run: python -m pip install .
      - uses: sigstore/gh-action-sigstore-python@v2.1.1
        with:
          inputs: file.txt

Note: Your workflow must have permission to request the OIDC token to authenticate with. This can be done by setting id-token: write on your job (as above) or workflow.

More information about permission settings can be found here.

Configuration

gh-action-sigstore-python takes a variety of configuration inputs, most of which are optional.

inputs

The inputs setting controls what files sigstore-python signs. At least one input must be provided unless release-signing-artifacts is set to true on release events.

To sign one or more files:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file0.txt file1.txt file2.txt

The inputs argument also supports file globbing:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: ./path/to/inputs/*.txt

Multiple lines are fine, and whitespace in filenames can also be escaped using POSIX shell lexing rules:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: |
      ./path/to/inputs/*.txt
      ./another/path/foo\ bar.txt
      ./a/third/path/"easier to quote than to escape".txt

Note

In versions of this action before 2.0.0, the inputs setting allowed for shell expansion. This was unintentional, and was removed with 2.0.0.

identity-token

Default: Empty (the GitHub Actions credential will be used)

The identity-token setting controls the OpenID Connect token provided to Fulcio. By default, the workflow will use the credentials found in the GitHub Actions environment.

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    identity-token: ${{ IDENTITY_TOKEN  }} # assigned elsewhere

oidc-client-id

Default: sigstore

The oidc-client-id setting controls the OpenID Connect client ID to provide to the OpenID Connect Server during OAuth2.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    oidc-client-id: alternative-sigstore-id

oidc-client-secret

Default: Empty (no OpenID Connect client secret provided by default)

The oidc-client-secret setting controls the OpenID Connect client secret to provide to the OpenID Connect Server during OAuth2.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    oidc-client-secret: alternative-sigstore-secret

signature

Default: Empty (signature files will get named as {input}.sig)

The signature setting controls the name of the output signature file. This setting does not work when signing multiple input files.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    signature: custom-signature-filename.sig

However, this example is invalid:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file0.txt file1.txt file2.txt
    signature: custom-signature-filename.sig

certificate

Default: Empty (certificate files will get named as {input}.crt)

The certificate setting controls the name of the output certificate file. This setting does not work when signing multiple input files.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    certificate: custom-certificate-filename.crt

However, this example is invalid:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file0.txt file1.txt file2.txt
    certificate: custom-certificate-filename.crt

bundle

Default: Empty (bundle files will get named as {input}.sigstore)

The bundle setting controls the name of the output Sigstore bundle. This setting does not work when signing multiple input files.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    bundle: custom-bundle.sigstore

However, this example is invalid:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file0.txt file1.txt file2.txt
    certificate: custom-bundle.sigstore

fulcio-url

Default: https://fulcio.sigstore.dev

The fulcio-url setting controls the Fulcio instance to retrieve the ephemeral signing certificate from. This setting cannot be used in combination with the staging setting.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    fulcio-url: https://fulcio.sigstage.dev

rekor-url

Default: https://rekor.sigstore.dev

The rekor-url setting controls the Rekor instance to upload the file signature to. This setting cannot be used in combination with the staging setting.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    rekor-url: https://rekor.sigstage.dev

ctfe

Default: ctfe.pub (the CTFE key embedded in sigstore-python)

The ctfe setting is a path to a PEM-encoded public key for the CT log. This setting cannot be used in combination with the staging setting.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    ctfe: ./path/to/ctfe.pub

rekor-root-pubkey

Default: rekor.pub (the Rekor key embedded in sigstore-python)

The rekor-root-pubkey setting is a path to a PEM-encoded public key for Rekor. This setting cannot be used in combination with staging setting.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    ctfe: ./path/to/rekor.pub

staging

Default: false

The staging setting controls whether or not sigstore-python uses sigstore's staging instances, instead of the default production instances.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    staging: true

verify

Default: false

The verify setting controls whether or not the generated signatures and certificates are verified with the sigstore verify subcommand after all files have been signed.

This is not strictly necessary but can act as a smoke test to ensure that all signing artifacts were generated properly and the signature was properly submitted to Rekor.

If verify is enabled, then you must also pass the verify-cert-identity and verify-oidc-issuer settings. Failing to pass these will produce an error.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    verify: true
    verify-oidc-issuer: https://some-oidc-issuer.example.com
    verify-cert-identity: some-identity

verify-cert-identity

Default: Empty

The verify-cert-identity setting controls whether to verify the Subject Alternative Name (SAN) of the signing certificate after signing has taken place. If it is set, sigstore-python will compare the certificate's SAN against the provided value.

This setting only applies if verify is set to true. Supplying it without verify: true will produce an error.

This setting may only be used in conjunction with verify-oidc-issuer. Supplying it without verify-oidc-issuer will produce an error.

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    verify: true
    verify-cert-identity: john.hancock@example.com
    verify-oidc-issuer: https://oauth2.sigstage.dev/auth

verify-oidc-issuer

Default: https://oauth2.sigstore.dev/auth

The verify-oidc-issuer setting controls whether to verify the issuer extension of the signing certificate after signing has taken place. If it is set, sigstore-python will compare the certificate's issuer extension against the provided value.

This setting only applies if verify is set to true. Supplying it without verify: true will produce an error.

This setting may only be used in conjunction with verify-cert-identity. Supplying it without verify-cert-identity will produce an error.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    verify: true
    verify-cert-identity: john.hancock@example.com
    verify-oidc-issuer: https://oauth2.sigstage.dev/auth

upload-signing-artifacts

Default: false

The upload-signing-artifacts setting controls whether or not sigstore-python creates workflow artifacts for the outputs produced by signing operations.

By default, no workflow artifacts are uploaded. When enabled, the default workflow artifact retention period is used.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    upload-signing-artifacts: true

release-signing-artifacts

Default: false

The release-signing-artifacts setting controls whether or not sigstore-python uploads signing artifacts to the release publishing event that triggered this run. This setting has no effect on non-release events.

If enabled, this setting also re-uploads and signs GitHub's default source code artifacts, as they are not guaranteed to be stable.

By default, no release assets are uploaded.

Requires the contents: write permission.

Example:

permissions:
  contents: write

# ...

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    release-signing-artifacts: true

On release events, it is also valid to have no explicit inputs. When used on release events with release-signing-artifacts: true, this action will sign any pre-existing release artifacts:

permissions:
  contents: write

# ...

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    # Only valid on release events
    release-signing-artifacts: true

Internal options

⚠️ Internal options ⚠️

Everything below is considered "internal," which means that it isn't part of the stable public settings and may be removed or changed at any points. You probably do not need these settings.

All internal options are prefixed with internal-be-careful-.

internal-be-careful-debug

Default: false

The internal-be-careful-debug setting enables additional debug logs, both within sigstore-python itself and the action's harness code. You can use it to debug troublesome configurations.

Example:

- uses: sigstore/gh-action-sigstore-python@v2.1.1
  with:
    inputs: file.txt
    internal-be-careful-debug: true

Licensing

gh-action-sigstore-python is licensed under the Apache 2.0 License.

Code of Conduct

Everyone interacting with this project is expected to follow the sigstore Code of Conduct

Security

Should you discover any security issues, please refer to sigstore's security process.

Info

gh-action-sigstore-python is developed as part of the sigstore project.

We also use a slack channel! Click here for the invite link.