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toolkit/packages/attest/src/provenance.ts

100 lines
3.0 KiB
TypeScript

import {attest, AttestOptions} from './attest'
import {getIDTokenClaims} from './oidc'
import type {Attestation, Predicate} from './shared.types'
const SLSA_PREDICATE_V1_TYPE = 'https://slsa.dev/provenance/v1'
const GITHUB_BUILDER_ID_PREFIX = 'https://github.com/actions/runner'
const GITHUB_BUILD_TYPE =
'https://slsa-framework.github.io/github-actions-buildtypes/workflow/v1'
const DEFAULT_ISSUER = 'https://token.actions.githubusercontent.com'
export type AttestProvenanceOptions = Omit<
AttestOptions,
'predicate' | 'predicateType'
> & {
issuer?: string
}
/**
* Builds an SLSA (Supply Chain Levels for Software Artifacts) provenance
* predicate using the GitHub Actions Workflow build type.
* https://slsa.dev/spec/v1.0/provenance
* https://github.com/slsa-framework/github-actions-buildtypes/tree/main/workflow/v1
* @param issuer - URL for the OIDC issuer. Defaults to the GitHub Actions token
* issuer.
* @returns The SLSA provenance predicate.
*/
export const buildSLSAProvenancePredicate = async (
issuer: string = DEFAULT_ISSUER
): Promise<Predicate> => {
const serverURL = process.env.GITHUB_SERVER_URL
const claims = await getIDTokenClaims(issuer)
// Split just the path and ref from the workflow string.
// owner/repo/.github/workflows/main.yml@main =>
// .github/workflows/main.yml, main
const [workflowPath, workflowRef] = claims.workflow_ref
.replace(`${claims.repository}/`, '')
.split('@')
return {
type: SLSA_PREDICATE_V1_TYPE,
params: {
buildDefinition: {
buildType: GITHUB_BUILD_TYPE,
externalParameters: {
workflow: {
ref: workflowRef,
repository: `${serverURL}/${claims.repository}`,
path: workflowPath
}
},
internalParameters: {
github: {
event_name: claims.event_name,
repository_id: claims.repository_id,
repository_owner_id: claims.repository_owner_id
}
},
resolvedDependencies: [
{
uri: `git+${serverURL}/${claims.repository}@${claims.ref}`,
digest: {
gitCommit: claims.sha
}
}
]
},
runDetails: {
builder: {
id: `${GITHUB_BUILDER_ID_PREFIX}/${claims.runner_environment}`
},
metadata: {
invocationId: `${serverURL}/${claims.repository}/actions/runs/${claims.run_id}/attempts/${claims.run_attempt}`
}
}
}
}
}
/**
* Attests the build provenance of the provided subject. Generates the SLSA
* build provenance predicate, assembles it into an in-toto statement, and
* attests it.
*
* @param options - The options for attesting the provenance.
* @returns A promise that resolves to the attestation.
*/
export async function attestProvenance(
options: AttestProvenanceOptions
): Promise<Attestation> {
const predicate = await buildSLSAProvenancePredicate(options.issuer)
return attest({
...options,
predicateType: predicate.type,
predicate: predicate.params
})
}