Files
pulse/scripts/verify-release-helm-chart.sh
pulse-triage[bot] 5e30bbb346 Recover Helm Pages from attested OCI charts
Keep convergence recoverable after short-lived Actions artifacts expire by preserving the exact digest-bound package already verified from GHCR.

Change-source: pulse-maintainer
2026-09-04 01:04:30 +01:00

106 lines
3.4 KiB
Bash
Executable File

#!/usr/bin/env bash
# Resolve the exact-version OCI Helm chart to its registry digest and verify
# that GitHub's signed build provenance binds it to the release source and the
# canonical hosted chart publisher. When an output path is supplied, preserve
# the exact OCI package whose digest and provenance passed those checks.
set -euo pipefail
if [ "$#" -lt 2 ] || [ "$#" -gt 5 ]; then
echo "Usage: $0 <tag> <source-sha> [owner/repo] [expected-digest] [output-chart]" >&2
exit 2
fi
TAG="$1"
SOURCE_SHA="$2"
REPOSITORY="${3:-${GITHUB_REPOSITORY:-rcourtman/Pulse}}"
EXPECTED_DIGEST="${4:-}"
OUTPUT_CHART="${5:-}"
OWNER="${REPOSITORY%%/*}"
VERSION="${TAG#v}"
SUBJECT="ghcr.io/${OWNER}/pulse-chart/pulse"
SIGNER_WORKFLOW="github.com/${REPOSITORY}/.github/workflows/publish-helm-chart.yml"
if [[ ! "$TAG" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(-((rc|alpha|beta)\.[0-9]+))?$ ]]; then
echo "Invalid release tag: ${TAG}" >&2
exit 1
fi
if [[ ! "$SOURCE_SHA" =~ ^[0-9a-f]{40}$ ]]; then
echo "Invalid release source SHA: ${SOURCE_SHA}" >&2
exit 1
fi
if [[ ! "$REPOSITORY" =~ ^[A-Za-z0-9_.-]+/[A-Za-z0-9_.-]+$ ]]; then
echo "Invalid GitHub repository: ${REPOSITORY}" >&2
exit 1
fi
if [ -n "$EXPECTED_DIGEST" ] && \
[[ ! "$EXPECTED_DIGEST" =~ ^sha256:[0-9a-f]{64}$ ]]; then
echo "Invalid expected Helm chart digest: ${EXPECTED_DIGEST}" >&2
exit 1
fi
for command in gh helm; do
if ! command -v "$command" >/dev/null 2>&1; then
echo "${command} is required to verify the release Helm chart." >&2
exit 1
fi
done
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
"${SCRIPT_DIR}/require-safe-gh-attestation.sh"
pull_dir="$(mktemp -d)"
cleanup() { rm -rf "$pull_dir"; }
trap cleanup EXIT
pull_output="$(
helm pull "oci://${SUBJECT}" \
--version "$VERSION" \
--destination "$pull_dir" 2>&1
)" || {
echo "$pull_output" >&2
echo "Unable to resolve the exact-version Helm chart ${SUBJECT}:${VERSION}." >&2
exit 1
}
printf '%s\n' "$pull_output" >&2
mapfile -t resolved_digests < <(
sed -nE 's/^Digest:[[:space:]]*(sha256:[0-9a-f]{64})\r?$/\1/p' \
<<<"$pull_output" | sort -u
)
if [ "${#resolved_digests[@]}" -ne 1 ]; then
echo "Helm did not report one exact OCI digest for ${SUBJECT}:${VERSION}." >&2
exit 1
fi
chart_digest="${resolved_digests[0]}"
if [ -n "$EXPECTED_DIGEST" ] && [ "$chart_digest" != "$EXPECTED_DIGEST" ]; then
echo "Exact-version Helm chart moved: expected ${EXPECTED_DIGEST}, observed ${chart_digest}." >&2
exit 1
fi
gh attestation verify "oci://${SUBJECT}@${chart_digest}" \
--repo "$REPOSITORY" \
--bundle-from-oci \
--signer-workflow "$SIGNER_WORKFLOW" \
--source-digest "$SOURCE_SHA" \
--deny-self-hosted-runners \
--predicate-type https://slsa.dev/provenance/v1 \
>/dev/null
if [ -n "$OUTPUT_CHART" ]; then
resolved_chart="${pull_dir}/pulse-${VERSION}.tgz"
if [ ! -f "$resolved_chart" ] || [ -L "$resolved_chart" ]; then
echo "Verified OCI pull did not produce one regular chart package: ${resolved_chart}" >&2
exit 1
fi
if [ -L "$OUTPUT_CHART" ]; then
echo "Refusing to replace symlink output path: ${OUTPUT_CHART}" >&2
exit 1
fi
install -m 0644 -- "$resolved_chart" "$OUTPUT_CHART"
fi
printf 'chart_digest=%s\n' "$chart_digest"
echo "[OK] Helm chart ${VERSION} and hosted build provenance resolve to ${chart_digest}." >&2