build: consume guest-components CoCo artefacts instead of building locally

guest-components' coco-extension-image workflow now publishes two artefacts from the same assembled rootfs, and kata consumes each on the matching path: * Monolithic confidential rootfs (Go runtime): the scratch OCI container image from the "Publish OCI container image" step (ghcr.io/confidential-containers/guest-components/coco-extension). install_coco_guest_components() resolves the per-arch manifest digest, verifies provenance, and exports the filesystem into kata-static-coco-guest-components.tar.zst (binaries, cryptsetup, pause bundle, ocicrypt config). This replaces the local guest-components compile and removes the separate pause-image dependency from confidential rootfs targets. * Composable extension (runtime-rs): the EROFS + dm-verity disk image from the "Publish disk image with ORAS" step (ghcr.io/confidential-containers/guest-components/coco-extension-disk). install_image_coco_extension() resolves the per-arch digest, verifies provenance, and oras-pulls that exact digest into kata-static. Both paths pin the guest-components revision under .externals.coco-guest-components in versions.yaml (version, container_image, and extension_image must stay in sync). Provenance verification uses gh attestation verify --bundle-from-oci and fails the build by default (VERIFY_COCO_EXTENSION_PROVENANCE=no to bypass; skipped on s390x where gh has no binary). The build container installs the GitHub CLI and forwards GITHUB_TOKEN from the runner into the container. Signed-off-by: Fabiano Fidêncio <ffidencio@nvidia.com> Assisted-by: Cursor <cursoragent@cursor.com>
2026-07-25 06:00:18 +00:00 · 2026-07-13 14:26:25 +02:00
parent e49ad473bb
commit cd75c2fac5
10 changed files with 316 additions and 158 deletions
--- a/.github/workflows/build-kata-static-tarball-amd64.yaml
+++ b/.github/workflows/build-kata-static-tarball-amd64.yaml
@@ -57,7 +57,6 @@ jobs:
          - ovmf
          - ovmf-sev
          - ovmf-tdx
-          - pause-image
          - qemu
          - qemu-snp-experimental
          - qemu-tdx-experimental
@@ -108,6 +107,8 @@ jobs:
          RELEASE: ${{ inputs.stage == 'release' && 'yes' || 'no' }}
          KBUILD_SIGN_PIN: ${{ contains(matrix.asset, 'nvidia') && secrets.KBUILD_SIGN_PIN || '' }}
          USE_DEVMAPPER: ${{ matrix.asset == 'agent' && 'yes' || 'no' }}
+          GH_TOKEN: ${{ github.token }}
+          VERIFY_COCO_EXTENSION_PROVENANCE: "yes"

      - name: Parse OCI image name and digest
        id: parse-oci-segments
@@ -266,6 +267,9 @@ jobs:
          TARGET_BRANCH: ${{ inputs.target-branch }}
          RELEASE: ${{ inputs.stage == 'release' && 'yes' || 'no' }}
          KBUILD_SIGN_PIN: ${{ contains(matrix.asset, 'nvidia') && secrets.KBUILD_SIGN_PIN || '' }}
+          # Used to verify the guest-components CoCo extension provenance.
+          GH_TOKEN: ${{ github.token }}
+          VERIFY_COCO_EXTENSION_PROVENANCE: "yes"

      - name: store-artifact ${{ matrix.asset }}
        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
--- a/.github/workflows/build-kata-static-tarball-arm64.yaml
+++ b/.github/workflows/build-kata-static-tarball-arm64.yaml
@@ -55,7 +55,6 @@ jobs:
          - kernel-nvidia-gpu
          - nydus
          - ovmf
-          - pause-image
          - qemu
          - virtiofsd
    concurrency:
@@ -101,6 +100,8 @@ jobs:
          RELEASE: ${{ inputs.stage == 'release' && 'yes' || 'no' }}
          KBUILD_SIGN_PIN: ${{ contains(matrix.asset, 'nvidia') && secrets.KBUILD_SIGN_PIN || '' }}
          USE_DEVMAPPER: ${{ matrix.asset == 'agent' && 'yes' || 'no' }}
+          GH_TOKEN: ${{ github.token }}
+          VERIFY_COCO_EXTENSION_PROVENANCE: "yes"

      - name: Parse OCI image name and digest
        id: parse-oci-segments
@@ -255,6 +256,8 @@ jobs:
          TARGET_BRANCH: ${{ inputs.target-branch }}
          RELEASE: ${{ inputs.stage == 'release' && 'yes' || 'no' }}
          KBUILD_SIGN_PIN: ${{ contains(matrix.asset, 'nvidia') && secrets.KBUILD_SIGN_PIN || '' }}
+          GH_TOKEN: ${{ github.token }}
+          VERIFY_COCO_EXTENSION_PROVENANCE: "yes"

      - name: store-artifact ${{ matrix.asset }}
        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
@@ -275,7 +278,6 @@ jobs:
          - busybox
          - coco-guest-components
          - kernel-nvidia-gpu-modules
-          - pause-image
    concurrency:
      group: ${{ github.workflow }}-${{ github.job }}-${{ github.event.pull_request.number || github.ref }}-arm-${{ toJSON(matrix) }}
      cancel-in-progress: true
--- a/.github/workflows/build-kata-static-tarball-s390x.yaml
+++ b/.github/workflows/build-kata-static-tarball-s390x.yaml
@@ -47,7 +47,6 @@ jobs:
          - coco-guest-components
          - fake-boot-image-se
          - kernel
-          - pause-image
          - qemu
          - virtiofsd
    concurrency:
@@ -99,6 +98,7 @@ jobs:
          TARGET_BRANCH: ${{ inputs.target-branch }}
          RELEASE: ${{ inputs.stage == 'release' && 'yes' || 'no' }}
          USE_DEVMAPPER: ${{ matrix.asset == 'agent' && 'yes' || 'no' }}
+          GH_TOKEN: ${{ github.token }}

      - name: Parse OCI image name and digest
        id: parse-oci-segments
@@ -237,6 +237,7 @@ jobs:
          ARTEFACT_REGISTRY_PASSWORD: ${{ secrets.GITHUB_TOKEN }}
          TARGET_BRANCH: ${{ inputs.target-branch }}
          RELEASE: ${{ inputs.stage == 'release' && 'yes' || 'no' }}
+          GH_TOKEN: ${{ github.token }}

      - name: store-artifact ${{ matrix.asset }}
        uses: actions/upload-artifact@b7c566a772e6b6bfb58ed0dc250532a479d7789f # v6.0.0
--- a/docs/design/composable-vm-images.md
+++ b/docs/design/composable-vm-images.md
@@ -568,27 +568,61 @@ arrive as packages — they are copied into the base layout explicitly:
 `veritysetup` and its library closure unconditionally, and the
 `mke2fs`/`mkfs.ext4`/`dd`/`mke2fs.conf` plain-storage tooling alongside it.

+#### CoCo guest components (monolithic confidential images)
+
+The Go runtime still boots a **monolithic** confidential image that bakes the
+CoCo guest components directly into the rootfs. Rather than compiling
+guest-components on the kata side, `install_coco_guest_components` pulls the
+scratch OCI **container** image guest-components publishes in the
+`coco-extension-image` workflow ("Publish OCI container image" step) at
+`ghcr.io/confidential-containers/guest-components/coco-extension`
+(`.externals.coco-guest-components.container_image`), verifies its provenance,
+and exports the filesystem into `kata-static-coco-guest-components.tar.zst`.
+This is distinct from the EROFS disk image (`extension_image`) used by the
+runtime-rs composable extension path. The container payload includes the
+guest-component binaries, `cryptsetup`, the pause bundle, and
+`etc/ocicrypt_config.json`, so confidential rootfs builds no longer need a
+separate `pause-image` tarball or a local guest-components compile.
+
 #### CoCo guest extension image

-The `kata-containers-coco-extension.img` is built by:
+The `kata-containers-coco-extension.img` is built and published by
+[guest-components](https://github.com/confidential-containers/guest-components)
+(`tools/coco-extension/`) as a multi-arch OCI index at
+`ghcr.io/confidential-containers/guest-components/coco-extension-disk`. Kata pins
+the guest-components revision in `versions.yaml` under
+`.externals.coco-guest-components` (`version`, `container_image`, and
+`extension_image` must stay in sync) and, at build time, `install_image_coco_extension`:

-1. Unpacking the CoCo guest components tarball into a temporary rootfs. Besides
-   the agent-launched binaries (attestation-agent, attestation-agent-nv,
-   confidential-data-hub, api-server-rest) this tarball also carries:
-   - `cryptsetup` under `usr/sbin` — the encrypted-storage binary for CDH
-     `secure_mount` (its shared libraries are resolved against the base; see
-     "Runtime dependencies").
-   - the NVIDIA attester libraries under `usr/local/lib` — `libnvat.so` plus its
-     non-glibc transitive closure (libxml2, zlib, lzma, the C++ runtime).
-2. Unpacking the pause image tarball into the same rootfs.
-3. Writing the component manifest to `etc/kata-extensions/components.toml`.
-4. Running the image builder with:
-   - `FS_TYPE=erofs` — EROFS filesystem for compact, read-only storage.
-   - `MEASURED_ROOTFS=yes` — creates a dm-verity hash partition.
-   - `SKIP_DAX_HEADER=yes` — no DAX header (virtio-blk, not NVDIMM).
-   - `SKIP_ROOTFS_CHECK=yes` — the extension has no `/sbin/init`.
-   - `BUILD_VARIANT=coco-extension` — produces a correctly named root hash file
-     (`root_hash_coco-extension.txt`).
+1. Resolves the per-architecture manifest digest from the index
+   (`oras resolve --platform linux/<arch>`).
+2. Verifies the provenance attestation guest-components published for that digest
+   (`gh attestation verify --repo confidential-containers/guest-components
+   --bundle-from-oci`). On amd64/arm64 CI sets
+   `VERIFY_COCO_EXTENSION_PROVENANCE=yes` to require it when `GH_TOKEN` is
+   available; locally it is skipped when no GitHub token is set. s390x always
+   skips because the GitHub CLI ships no s390x build.
+3. Pulls that exact digest (`oras pull`) so the installed image is byte-for-byte
+   the artefact whose provenance was verified.
+
+!!! note
+    Provenance verification runs when `GH_TOKEN` or `GITHUB_TOKEN` is available
+    (CI forwards the runner token automatically). Local builds without a token
+    skip verification with a warning. Set `VERIFY_COCO_EXTENSION_PROVENANCE=yes`
+    to require it, or `no` to disable it explicitly.
+
+The guest-components build assembles a rootfs that carries the agent-launched
+binaries (attestation-agent, attestation-agent-nv, confidential-data-hub,
+api-server-rest), `cryptsetup` under `usr/sbin`, the NVIDIA attester libraries
+under `usr/local/lib`, the pause bundle, and the component manifest at
+`etc/kata-extensions/components.toml`, then formats it as:
+
+- `FS_TYPE=erofs` — EROFS filesystem for compact, read-only storage.
+- `MEASURED_ROOTFS=yes` — creates a dm-verity hash partition (except on s390x).
+- `SKIP_DAX_HEADER=yes` — no DAX header (virtio-blk, not NVDIMM).
+- `SKIP_ROOTFS_CHECK=yes` — the extension has no `/sbin/init`.
+- `BUILD_VARIANT=coco-extension` — produces a correctly named root hash file
+  (`root_hash_coco-extension.txt`).

 The resulting image is a two-partition disk:

--- a/tools/packaging/kata-deploy/local-build/Makefile
+++ b/tools/packaging/kata-deploy/local-build/Makefile
@@ -77,7 +77,6 @@ NVGPU_BASE_TARBALLS = \
 	ovmf-sev-tarball \
 	ovmf-tdx-tarball \
 	ovmf-tarball \
-	pause-image-tarball \
 	qemu-snp-experimental-tarball \
 	qemu-tdx-experimental-tarball \
 	qemu-tarball \
@@ -91,7 +90,6 @@ NVGPU_BASE_TARBALLS = \
 	$(PUBLISH_COMPONENT_TARBALLS) \
 	kernel-nvidia-gpu-tarball \
 	ovmf-tarball \
-	pause-image-tarball \
 	qemu-tarball \
 	virtiofsd-tarball \
 	serial-targets
@@ -254,19 +252,18 @@ DEPS := agent-tarball
 rootfs-image-tarball: $(DEPS)
 	${MAKE} $@-build

-DEPS := agent-tarball pause-image-tarball coco-guest-components-tarball kernel-tarball
+DEPS := agent-tarball coco-guest-components-tarball kernel-tarball
 rootfs-image-confidential-tarball: $(DEPS)
 	${MAKE} $@-build

-DEPS := pause-image-tarball coco-guest-components-tarball
-rootfs-image-coco-extension-tarball: $(DEPS)
+rootfs-image-coco-extension-tarball:
 	${MAKE} $@-build

 DEPS := agent-tarball
 rootfs-image-mariner-tarball: $(DEPS)
 	${MAKE} $@-build

-DEPS := agent-tarball pause-image-tarball coco-guest-components-tarball kernel-tarball
+DEPS := agent-tarball coco-guest-components-tarball kernel-tarball
 rootfs-initrd-confidential-tarball: $(DEPS)
 	${MAKE} $@-build

@@ -278,7 +275,7 @@ DEPS := agent-tarball busybox-tarball kernel-nvidia-gpu-tarball
 rootfs-image-nvidia-gpu-tarball: $(DEPS)
 	${MAKE} $@-build

-DEPS := agent-tarball busybox-tarball pause-image-tarball coco-guest-components-tarball kernel-nvidia-gpu-tarball
+DEPS := agent-tarball busybox-tarball coco-guest-components-tarball kernel-nvidia-gpu-tarball
 rootfs-image-nvidia-gpu-confidential-tarball: $(DEPS)
 	${MAKE} $@-build

--- a/tools/packaging/kata-deploy/local-build/dockerbuild/Dockerfile
+++ b/tools/packaging/kata-deploy/local-build/dockerbuild/Dockerfile
@@ -10,10 +10,11 @@ ENV TZ=Etc/UTC

 COPY install_yq.sh /usr/bin/install_yq.sh
 COPY install_oras.sh /usr/bin/install_oras.sh
+COPY install_gh.sh /usr/bin/install_gh.sh

 SHELL ["/bin/bash", "-o", "pipefail", "-c"]

-# Install yq, oras, and docker
+# Install yq, oras, gh, and docker
 RUN apt-get update && \
    apt-get install -y --no-install-recommends \
        ca-certificates \
@@ -25,7 +26,8 @@ RUN apt-get update && \
        sudo && \
    apt-get clean && rm -rf /var/lib/apt/lists/ && \
    install_yq.sh && \
-    install_oras.sh
+    install_oras.sh && \
+    install_gh.sh

 ARG IMG_USER=kata-builder
 ARG UID=1000
--- a/tools/packaging/kata-deploy/local-build/dockerbuild/install_gh.sh
+++ b/tools/packaging/kata-deploy/local-build/dockerbuild/install_gh.sh
@@ -0,0 +1,52 @@
+#!/bin/bash
+#
+# Copyright (c) 2026 Kata Containers contributors
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+# Install the GitHub CLI, used to verify the provenance attestation of the
+# guest-components CoCo extension image (see kata-deploy-binaries.sh).
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+install_dest="/usr/local/bin"
+
+# Keep in sync with a version that ships "gh attestation verify".
+gh_required_version="2.62.0"
+
+if command -v gh &>/dev/null; then
+	echo "gh is already installed in the system"
+	exit 0
+fi
+
+arch=$(uname -m)
+case "${arch}" in
+	x86_64) arch="amd64" ;;
+	aarch64) arch="arm64" ;;
+	s390x)
+		# The GitHub CLI publishes no linux/s390x build, so provenance
+		# verification is skipped on s390x by the caller.
+		echo "gh CLI has no s390x build; skipping installation"
+		exit 0
+		;;
+	*)
+		echo "Unsupported architecture for gh CLI: ${arch}"
+		exit 1
+		;;
+esac
+
+gh_tarball="gh_${gh_required_version}_linux_${arch}.tar.gz"
+
+echo "Downloading gh ${gh_required_version}"
+tmp_dir="$(mktemp -d)"
+curl -fsSL -o "${tmp_dir}/${gh_tarball}" \
+	"https://github.com/cli/cli/releases/download/v${gh_required_version}/${gh_tarball}"
+
+echo "Installing gh to ${install_dest}"
+tar -C "${tmp_dir}" -xzf "${tmp_dir}/${gh_tarball}"
+sudo install -D --mode 0755 \
+	"${tmp_dir}/gh_${gh_required_version}_linux_${arch}/bin/gh" \
+	"${install_dest}/gh"
+rm -rf "${tmp_dir}"
--- a/tools/packaging/kata-deploy/local-build/kata-deploy-binaries-in-docker.sh
+++ b/tools/packaging/kata-deploy/local-build/kata-deploy-binaries-in-docker.sh
@@ -131,6 +131,8 @@ docker run \
 	--env REPO_URL_X86_64="${REPO_URL_X86_64}" \
 	--env REPO_COMPONENTS="${REPO_COMPONENTS}" \
 	--env AGENT_POLICY="${AGENT_POLICY}" \
+	--env GH_TOKEN="${GH_TOKEN:-${GITHUB_TOKEN:-}}" \
+	--env VERIFY_COCO_EXTENSION_PROVENANCE="${VERIFY_COCO_EXTENSION_PROVENANCE:-}" \
 	--env USE_DEVMAPPER="${USE_DEVMAPPER}" \
 	--env RUNTIME_CHOICE="${RUNTIME_CHOICE}" \
 	--env STATIC_RUNTIME="${STATIC_RUNTIME:-}" \
--- a/tools/packaging/kata-deploy/local-build/kata-deploy-binaries.sh
+++ b/tools/packaging/kata-deploy/local-build/kata-deploy-binaries.sh
@@ -29,7 +29,6 @@ readonly versions_yaml="${repo_root_dir}/versions.yaml"

 readonly busybox_builder="${static_build_dir}/busybox/build.sh"
 readonly agent_builder="${static_build_dir}/agent/build.sh"
-readonly coco_guest_components_builder="${static_build_dir}/coco-guest-components/build.sh"
 readonly clh_builder="${static_build_dir}/cloud-hypervisor/build-static-clh.sh"
 readonly firecracker_builder="${static_build_dir}/firecracker/build-static-firecracker.sh"
 readonly kernel_builder="${static_build_dir}/kernel/build.sh"
@@ -352,15 +351,144 @@ get_coco_guest_components_tarball_path() {
 }

 get_latest_coco_guest_components_artefact_and_builder_image_version() {
-	local coco_guest_components_version
-	coco_guest_components_version=$(get_from_kata_deps ".externals.coco-guest-components.version")
-	local coco_guest_components_toolchain
-	coco_guest_components_toolchain=$(get_from_kata_deps ".externals.coco-guest-components.toolchain")
-	local latest_coco_guest_components_artefact="${coco_guest_components_version}-${coco_guest_components_toolchain}"
-	local latest_coco_guest_components_builder_image
-	latest_coco_guest_components_builder_image="$(get_coco_guest_components_image_name)"
+	echo "$(get_from_kata_deps ".externals.coco-guest-components.version")-$(get_coco_extension_oci_arch)"
+}

-	echo "${latest_coco_guest_components_artefact}-${latest_coco_guest_components_builder_image}"
+get_coco_extension_oci_arch() {
+	arch_to_golang "$(uname -m)"
+}
+
+# Multi-arch scratch OCI container image from guest-components' "Publish OCI
+# container image" step (coco-extension-image.yml). This is the assembled guest
+# components rootfs as a container, not the EROFS disk image (extension_image).
+get_coco_guest_components_container_image_ref() {
+	local version image
+	version="$(get_from_kata_deps ".externals.coco-guest-components.version")"
+	image="$(get_from_kata_deps ".externals.coco-guest-components.container_image")"
+	[[ -n "${version}" ]] || die "Failed to get coco-guest-components version from versions.yaml"
+	[[ -n "${image}" ]] || die "Failed to get coco-guest-components container_image from versions.yaml"
+
+	echo "${image}:${version}"
+}
+
+# The extension disk image is published as a multi-arch OCI index tagged with the
+# guest-components commit; the per-arch selection happens at pull time.
+get_coco_extension_disk_image_ref() {
+	local version image
+	version="$(get_from_kata_deps ".externals.coco-guest-components.version")"
+	image="$(get_from_kata_deps ".externals.coco-guest-components.extension_image")"
+	[[ -n "${version}" ]] || die "Failed to get coco-guest-components version from versions.yaml"
+	[[ -n "${image}" ]] || die "Failed to get coco-guest-components extension_image from versions.yaml"
+
+	echo "${image}:${version}"
+}
+
+# GitHub "owner/repo" that owns the provenance attestation, derived from the
+# guest-components URL so it never drifts from the pinned source.
+get_coco_extension_provenance_repo() {
+	local url
+	url="$(get_from_kata_deps ".externals.coco-guest-components.url")"
+	url="${url%/}"
+	echo "${url#https://github.com/}"
+}
+
+get_latest_coco_extension_artefact_version() {
+	echo "$(get_from_kata_deps ".externals.coco-guest-components.version")-$(get_coco_extension_oci_arch)"
+}
+
+ensure_oras_installed() {
+	if command -v oras &>/dev/null; then
+		return 0
+	fi
+
+	local install_oras_script="${repo_root_dir}/tools/packaging/kata-deploy/local-build/dockerbuild/install_oras.sh"
+	[[ -f "${install_oras_script}" ]] || die "oras is required to pull the CoCo extension image"
+	"${install_oras_script}"
+}
+
+ensure_gh_installed() {
+	if command -v gh &>/dev/null; then
+		return 0
+	fi
+
+	local install_gh_script="${repo_root_dir}/tools/packaging/kata-deploy/local-build/dockerbuild/install_gh.sh"
+	[[ -f "${install_gh_script}" ]] || return 1
+	"${install_gh_script}" || return 1
+	command -v gh &>/dev/null
+}
+
+# Verify the guest-components provenance attestation bound to a per-arch OCI
+# manifest digest (container or disk image).
+#
+# Verification policy:
+#   VERIFY_COCO_EXTENSION_PROVENANCE=no  — always skip
+#   VERIFY_COCO_EXTENSION_PROVENANCE=yes — always verify (CI); fail if gh/token missing
+#   unset (default)                      — verify when GH_TOKEN/GITHUB_TOKEN is set,
+#                                          otherwise skip with a warning (local builds)
+verify_guest_components_oci_provenance() {
+	local image="$1"
+	local digest="$2"
+	local token="${GH_TOKEN:-${GITHUB_TOKEN:-}}"
+
+	if [[ "${VERIFY_COCO_EXTENSION_PROVENANCE:-}" == "no" ]]; then
+		warn "guest-components provenance verification disabled (VERIFY_COCO_EXTENSION_PROVENANCE=no)"
+		return 0
+	fi
+
+	# The GitHub CLI has no s390x build; provenance cannot be verified there even
+	# when CI sets VERIFY_COCO_EXTENSION_PROVENANCE=yes.
+	if [[ "$(uname -m)" == "s390x" ]]; then
+		warn "skipping guest-components provenance verification on s390x for ${image}@${digest}"
+		return 0
+	fi
+
+	if [[ -z "${token}" ]]; then
+		if [[ "${VERIFY_COCO_EXTENSION_PROVENANCE:-}" == "yes" ]]; then
+			die "VERIFY_COCO_EXTENSION_PROVENANCE=yes requires GH_TOKEN or GITHUB_TOKEN"
+		fi
+		warn "No GH_TOKEN/GITHUB_TOKEN set; skipping guest-components provenance verification for ${image}@${digest}"
+		return 0
+	fi
+
+	if ! ensure_gh_installed; then
+		die "gh CLI is required to verify guest-components provenance (set VERIFY_COCO_EXTENSION_PROVENANCE=no to bypass)"
+	fi
+
+	local repo
+	repo="$(get_coco_extension_provenance_repo)"
+	info "Verifying provenance of ${image}@${digest} against ${repo}"
+	export GH_TOKEN="${token}"
+	# --bundle-from-oci reads the attestation guest-components pushed alongside the
+	# image (actions/attest push-to-registry) instead of the GitHub API.
+	gh attestation verify "oci://${image}@${digest}" \
+		--repo "${repo}" \
+		--bundle-from-oci \
+		|| die "Provenance verification failed for ${image}@${digest}"
+}
+
+# Pull the published scratch OCI container image (coco-extension), verify its
+# provenance, and export the rootfs into destdir for monolithic confidential images.
+install_coco_guest_components_from_oci() {
+	ensure_oras_installed
+
+	local image_ref image go_arch digest cid
+	image_ref="$(get_coco_guest_components_container_image_ref)"
+	image="${image_ref%%:*}"
+	go_arch="$(get_coco_extension_oci_arch)"
+
+	digest="$(oras resolve --platform "linux/${go_arch}" "${image_ref}")" \
+		|| die "Failed to resolve ${image_ref} for linux/${go_arch}; bump .externals.coco-guest-components.version in versions.yaml once guest-components has published the image"
+
+	verify_guest_components_oci_provenance "${image}" "${digest}"
+
+	info "Pull and extract CoCo guest components from ${image}@${digest} (linux/${go_arch})"
+
+	docker pull "${image}@${digest}"
+	# coco-extension is FROM scratch with no CMD/ENTRYPOINT; docker create needs
+	# an executable that exists in the image rootfs (we never run the container).
+	cid="$(docker create "${image}@${digest}" /usr/local/bin/attestation-agent --help)"
+	docker export "${cid}" | tar -xf - -C "${destdir}"
+	docker rm -f "${cid}" >/dev/null
 }

 get_pause_image_tarball_path() {
@@ -481,10 +609,8 @@ install_image() {
 		fi

 		# Both the standard and NVIDIA confidential images bake the CoCo
-		# guest components + pause image into the rootfs, so factor them
-		# into the cache key.
+		# guest components (including the pause bundle) into the rootfs.
 		latest_artefact+="-$(get_latest_coco_guest_components_artefact_and_builder_image_version)"
-		latest_artefact+="-$(get_latest_pause_image_artefact_and_builder_image_version)"
 	fi

 	if [[ "${variant}" == "nvidia-gpu" || "${variant}" == "nvidia-gpu-extension" ]]; then
@@ -534,15 +660,13 @@ install_image() {

 	if [[ -n "${variant}" ]]; then
 		# Both the standard confidential image and the NVIDIA confidential
-		# image bake the CoCo guest components + pause image into the
-		# rootfs, so each stays a usable standalone monolithic CoCo image.
-		# The runtime-rs split path instead ships these in the separate
+		# image bake the CoCo guest components (including the pause bundle)
+		# into the rootfs, so each stays a usable standalone monolithic CoCo image.
+		# The runtime-rs split path instead ships these in the separately published
 		# CoCo extension image (rootfs-image-coco-extension).
 		if [[ "${variant}" == *confidential ]]; then
 			COCO_GUEST_COMPONENTS_TARBALL="$(get_coco_guest_components_tarball_path)"
 			export COCO_GUEST_COMPONENTS_TARBALL
-			PAUSE_IMAGE_TARBALL="$(get_pause_image_tarball_path)"
-			export PAUSE_IMAGE_TARBALL
 		fi
 	fi

@@ -611,15 +735,15 @@ install_image_confidential() {
 }

 #Install CoCo extension image (erofs+verity, contains CoCo guest components + pause)
+#
+# The disk image is built and published by guest-components
+# (ghcr.io/confidential-containers/guest-components/coco-extension-disk) as a
+# multi-arch OCI index. Kata resolves the per-arch manifest digest, verifies its
+# provenance attestation, and pulls exactly that digest into kata-static.
 install_image_coco_extension() {
 	local component="rootfs-image-coco-extension"

-	local coco_last_commit
-	coco_last_commit="$(get_latest_coco_guest_components_artefact_and_builder_image_version)"
-	local pause_last_commit
-	pause_last_commit="$(get_latest_pause_image_artefact_and_builder_image_version)"
-
-	latest_artefact="$(get_kata_version)-coco-extension-${coco_last_commit}-${pause_last_commit}"
+	latest_artefact="$(get_kata_version)-coco-extension-$(get_latest_coco_extension_artefact_version)"
 	latest_builder_image=""

 	install_cached_tarball_component \
@@ -630,114 +754,50 @@ install_image_coco_extension() {
 		"${final_tarball_path}" \
 		&& return 0

-	info "Create CoCo extension image"
+	ensure_oras_installed

-	# Use a temp dir under the repo root so the path is valid both inside
-	# the outer build-kata-deploy container and in the nested image-builder
-	# container (Docker-in-Docker mounts use host paths).
-	local extension_rootfs
-	extension_rootfs="$(mktemp -d "${repo_root_dir}/.coco-extension-rootfs.XXXX")"
+	local disk_image_ref image go_arch
+	disk_image_ref="$(get_coco_extension_disk_image_ref)"
+	image="${disk_image_ref%%:*}"
+	go_arch="$(get_coco_extension_oci_arch)"

-	COCO_GUEST_COMPONENTS_TARBALL="$(get_coco_guest_components_tarball_path)"
-	PAUSE_IMAGE_TARBALL="$(get_pause_image_tarball_path)"
+	# Resolve the per-arch manifest digest out of the multi-arch index. This is the
+	# subject guest-components' provenance attestation is bound to, so we verify it
+	# and then pull that exact digest (avoiding a resolve/pull TOCTOU window).
+	local digest
+	digest="$(oras resolve --platform "linux/${go_arch}" "${disk_image_ref}")" \
+		|| die "Failed to resolve ${disk_image_ref} for linux/${go_arch}; bump .externals.coco-guest-components.version in versions.yaml once guest-components has published the image"

-	info "Unpacking CoCo guest components into extension rootfs"
-	tar --zstd -xvf "${COCO_GUEST_COMPONENTS_TARBALL}" -C "${extension_rootfs}"
+	verify_guest_components_oci_provenance "${image}" "${digest}"

-	info "Unpacking pause image into extension rootfs"
-	tar --zstd -xvf "${PAUSE_IMAGE_TARBALL}" -C "${extension_rootfs}"
+	info "Pull CoCo extension disk image from ${image}@${digest} (linux/${go_arch})"

-	# Data-driven extension manifest consumed by kata-agent. It describes the
-	# components shipped in this extension so the agent needs no per-bundle code
-	# changes. All paths are relative to the extension mount point
-	# (/run/kata-extensions/coco). The "${var}" tokens in the [[process]] entries are
-	# substituted by kata-agent from its runtime context.
-	info "Writing CoCo extension component manifest"
-	local manifest_dir="${extension_rootfs}/etc/kata-extensions"
-	mkdir -p "${manifest_dir}"
-	cat > "${manifest_dir}/components.toml" <<'EOF'
-schema_version = 1
+	local pull_dir
+	pull_dir="$(mktemp -d)"
+	pushd "${pull_dir}" >/dev/null
+	if ! oras pull "${image}@${digest}" --no-tty; then
+		popd >/dev/null
+		rm -rf "${pull_dir}"
+		die "Failed to pull CoCo extension image ${image}@${digest}"
+	fi

-[paths]
-"ocicrypt-config" = "etc/ocicrypt_config.json"
-"pause-bundle"    = "pause_bundle"
-
-[[process]]
-id            = "attestation-agent"
-level         = 1
-args          = ["--attestation_sock", "${aa_attestation_uri}"]
-optional_args = [{ when = "initdata_toml_path", args = ["--initdata-toml", "${initdata_toml_path}"] }]
-config        = "${aa_config_path}"
-wait_socket   = "${aa_attestation_socket}"
-timeout_secs  = "${launch_process_timeout}"
-# The extension ships both the stock attestation-agent and the NVIDIA-attester
-# build; the consumer selects one via the "attester_variant" context value
-# (kata-agent uses "default", NVRC uses "nvidia").
-select        = "${attester_variant}"
-
-  [process.variants.default]
-  path = "usr/local/bin/attestation-agent"
-
-  [process.variants.nvidia]
-  path = "usr/local/bin/attestation-agent-nv"
-  # attestation-agent-nv links libnvat.so (bundled in this CoCo extension under
-  # usr/local/lib), which dlopens libnvidia-ml.so.1 for GPU attestation evidence.
-  # Only NVAT's own libs need LD_LIBRARY_PATH: NVML lives in the GPU extension,
-  # which NVRC folds into the guest loader cache before starting kata-agent, so it
-  # resolves without a path here (see NVRC gpu::setup).
-  env  = { LD_LIBRARY_PATH = "${extension_root}/usr/local/lib" }
-
-[[process]]
-id           = "confidential-data-hub"
-level        = 2
-path         = "usr/local/bin/confidential-data-hub"
-config       = "${cdh_config_path}"
-# CDH's secure_mount shells out (by PATH lookup) to cryptsetup for encrypted
-# storage and to mke2fs/mkfs.ext4/dd for the filesystem. cryptsetup is CoCo-only
-# and ships in this extension under usr/sbin (see
-# build-static-coco-guest-components.sh); the plain mkfs/dd tooling lives in the
-# nvidia base image's /sbin and /bin. The agent launches CDH with
-# PATH=/bin:/sbin:/usr/bin:/usr/sbin, but setting any env here overrides it
-# wholesale, so prepend the extension's usr/sbin and restore the base dirs.
-env          = { OCICRYPT_KEYPROVIDER_CONFIG = "${ocicrypt_config_path}", PATH = "${extension_root}/usr/sbin:/bin:/sbin:/usr/bin:/usr/sbin" }
-wait_socket  = "${cdh_socket}"
-timeout_secs = "${launch_process_timeout}"
-
-[[process]]
-id           = "api-server-rest"
-level        = 3
-path         = "usr/local/bin/api-server-rest"
-args         = ["--features", "${rest_api_features}"]
-timeout_secs = "0"
-EOF
+	[[ -f kata-containers-coco-extension.img ]] || die "CoCo extension pull did not contain kata-containers-coco-extension.img"

 	local install_dir="${destdir}/${prefix}/share/kata-containers/"
 	mkdir -p "${install_dir}"
+	install -D --mode 0644 kata-containers-coco-extension.img \
+		"${install_dir}/kata-containers-coco-extension.img"

-	local image_builder="${repo_root_dir}/tools/osbuilder/image-builder/image_builder.sh"
-
-	export USE_DOCKER="1"
-	export BUILD_VARIANT="coco-extension"
-	export FS_TYPE="erofs"
-	# Mirror the base/confidential images: s390x does not use a measured rootfs
-	# (Secure Execution measures the guest through a different mechanism), so the
-	# extension carries no dm-verity hash there and is mounted off its raw
-	# partition instead.
-	if [[ "${ARCH}" == "s390x" ]]; then
-		export MEASURED_ROOTFS="no"
-	else
-		export MEASURED_ROOTFS="yes"
-	fi
-	export SKIP_DAX_HEADER="yes"
-	export SKIP_ROOTFS_CHECK="yes"
-
-	"${image_builder}" -o "${install_dir}/kata-containers-coco-extension.img" "${extension_rootfs}"
-
-	if [[ -e "${install_dir}/root_hash_coco-extension.txt" ]]; then
+	if [[ -f root_hash_coco-extension.txt ]]; then
+		install -D --mode 0644 root_hash_coco-extension.txt \
+			"${install_dir}/root_hash_coco-extension.txt"
 		info "Root hash file: ${install_dir}/root_hash_coco-extension.txt"
+	elif [[ "${ARCH}" != "s390x" ]]; then
+		die "Expected root_hash_coco-extension.txt in ${disk_image_ref}"
 	fi

-	rm -rf "${extension_rootfs}"
+	popd >/dev/null
+	rm -rf "${pull_dir}"
 }

 #Install cbl-mariner guest image
@@ -792,7 +852,6 @@ install_initrd() {
 			latest_artefact+="-$(get_latest_kernel_artefact_and_builder_image_version)"
 		fi
 		latest_artefact+="-$(get_latest_coco_guest_components_artefact_and_builder_image_version)"
-		latest_artefact+="-$(get_latest_pause_image_artefact_and_builder_image_version)"
 	fi

 	if [[ "${variant}" == "nvidia-gpu" ]]; then
@@ -819,8 +878,6 @@ install_initrd() {
 		if [[ "${variant}" == *confidential ]]; then
 			COCO_GUEST_COMPONENTS_TARBALL="$(get_coco_guest_components_tarball_path)"
 			export COCO_GUEST_COMPONENTS_TARBALL
-			PAUSE_IMAGE_TARBALL="$(get_pause_image_tarball_path)"
-			export PAUSE_IMAGE_TARBALL
 		fi
 	else
 		# Vanilla initrd uses kata-agent as /sbin/init (no systemd).
@@ -1445,9 +1502,9 @@ install_agent() {
 }

 install_coco_guest_components() {
-	latest_artefact="$(get_from_kata_deps ".externals.coco-guest-components.version")-$(get_from_kata_deps ".externals.coco-guest-components.toolchain")"
+	latest_artefact="$(get_latest_coco_guest_components_artefact_and_builder_image_version)"
 	artefact_tag="$(get_from_kata_deps ".externals.coco-guest-components.version")"
-	latest_builder_image="$(get_coco_guest_components_image_name)"
+	latest_builder_image=""

 	install_cached_tarball_component \
 		"${build_target}" \
@@ -1457,8 +1514,8 @@ install_coco_guest_components() {
 		"${final_tarball_path}" \
 		&& return 0

-	info "build static coco-guest-components"
-	DESTDIR="${destdir}" "${coco_guest_components_builder}"
+	info "Pull published CoCo guest components OCI container image"
+	install_coco_guest_components_from_oci
 }

 install_pause_image() {
--- a/versions.yaml
+++ b/versions.yaml
@@ -272,8 +272,15 @@ externals:
  coco-guest-components:
    description: "Provides attested key unwrapping for image decryption"
    url: "https://github.com/confidential-containers/guest-components/"
-    version: "da8d93f2797088a5f0636c8c1eeb31da73784fe8"
-    toolchain: "1.90.0"
+    version: "fff3a966b7b1d1654d172a7cd81c0f563721ff0b"
+    # Scratch OCI container image (guest-components "Publish OCI container image"
+    # step). Consumed by monolithic confidential rootfs builds.
+    # yamllint disable-line rule:line-length
+    container_image: "ghcr.io/confidential-containers/guest-components/coco-extension"
+    # EROFS + dm-verity disk image (guest-components "Publish disk image with ORAS"
+    # step). Consumed by the runtime-rs composable extension path.
+    # yamllint disable-line rule:line-length
+    extension_image: "ghcr.io/confidential-containers/guest-components/coco-extension-disk"

  coco-trustee:
    description: "Provides attestation and secret delivery components"