From d7f1f97a282572fca42ab5ae7517018ccac3ddfd Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 09:46:09 +0200
Subject: [PATCH 1/7] Add M0.9 attestation verification

---
 scripts/qualify_attestations.sh | 101 ++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 scripts/qualify_attestations.sh

diff --git a/scripts/qualify_attestations.sh b/scripts/qualify_attestations.sh
new file mode 100644
index 0000000..eed2536
--- /dev/null
+++ b/scripts/qualify_attestations.sh
@@ -0,0 +1,101 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+IMAGE="${IMAGE:-ghcr.io/ploos-as/glowing-bear}"
+VERSION="${VERSION:?VERSION is required}"
+
+if [[ "$VERSION" == v* ]]; then
+  VERSION="${VERSION#v}"
+fi
+
+if [[ ! "$VERSION" =~ ^[0-9]+\.[0-9]+\.[0-9]+([.-][0-9A-Za-z.-]+)?$ ]]; then
+  echo "release version is not semver-like: $VERSION" >&2
+  exit 1
+fi
+
+primary="$IMAGE:$VERSION"
+workdir="$(mktemp -d)"
+trap 'rm -rf "$workdir"' EXIT
+
+index_json="$workdir/index.json"
+docker buildx imagetools inspect --raw "$primary" > "$index_json"
+
+platform_digests=()
+while IFS= read -r digest; do
+  [[ -n "$digest" ]] && platform_digests+=("$digest")
+done < <(
+  jq -r '.manifests[]
+    | select(.platform.os == "linux")
+    | select(.platform.architecture == "amd64" or .platform.architecture == "arm64")
+    | .digest' "$index_json"
+)
+
+if [[ "${#platform_digests[@]}" -lt 2 ]]; then
+  echo "$primary does not expose both required Linux platform manifests" >&2
+  exit 1
+fi
+
+attestation_rows="$workdir/attestations.tsv"
+jq -r '.manifests[]
+  | select(.platform.os == "unknown" and .platform.architecture == "unknown")
+  | select(.annotations["vnd.docker.reference.type"] == "attestation-manifest")
+  | [.digest, .annotations["vnd.docker.reference.digest"]] | @tsv' \
+  "$index_json" > "$attestation_rows"
+
+if [[ ! -s "$attestation_rows" ]]; then
+  echo "$primary has no BuildKit attestation manifests" >&2
+  exit 1
+fi
+
+for platform_digest in "${platform_digests[@]}"; do
+  attestation_digest="$(awk -F '\t' -v d="$platform_digest" '$2 == d {print $1; exit}' "$attestation_rows")"
+  if [[ -z "$attestation_digest" ]]; then
+    echo "missing attestation manifest for platform digest $platform_digest" >&2
+    exit 1
+  fi
+
+  manifest_json="$workdir/${attestation_digest#sha256:}.json"
+  docker buildx imagetools inspect --raw "$IMAGE@$attestation_digest" > "$manifest_json"
+
+  linked_digest="$(jq -r '.annotations["vnd.docker.reference.digest"] // empty' "$manifest_json")"
+  reference_type="$(jq -r '.annotations["vnd.docker.reference.type"] // empty' "$manifest_json")"
+
+  if [[ "$linked_digest" != "$platform_digest" ]]; then
+    echo "attestation $attestation_digest links to $linked_digest, expected $platform_digest" >&2
+    exit 1
+  fi
+  if [[ "$reference_type" != "attestation-manifest" ]]; then
+    echo "unexpected attestation reference type for $attestation_digest: $reference_type" >&2
+    exit 1
+  fi
+
+  jq -e '[.layers[] | select(.mediaType == "application/vnd.in-toto+json")] | length >= 2' \
+    "$manifest_json" >/dev/null || {
+      echo "attestation $attestation_digest does not contain the expected in-toto layers" >&2
+      exit 1
+    }
+
+  jq -e '.layers[]
+    | select(.mediaType == "application/vnd.in-toto+json")
+    | select(.annotations["in-toto.io/predicate-type"] == "https://slsa.dev/provenance/v0.2")
+    | select(.size > 0)
+    | .digest | test("^sha256:[0-9a-f]{64}$")' \
+    "$manifest_json" >/dev/null || {
+      echo "attestation $attestation_digest is missing a valid SLSA provenance descriptor" >&2
+      exit 1
+    }
+
+  jq -e '.layers[]
+    | select(.mediaType == "application/vnd.in-toto+json")
+    | select(.annotations["in-toto.io/predicate-type"] == "https://spdx.dev/Document")
+    | select(.size > 0)
+    | .digest | test("^sha256:[0-9a-f]{64}$")' \
+    "$manifest_json" >/dev/null || {
+      echo "attestation $attestation_digest is missing a valid SPDX SBOM descriptor" >&2
+      exit 1
+    }
+
+  echo "Qualified SLSA provenance and SPDX SBOM for $platform_digest via $attestation_digest"
+done
+
+echo "M0.9 attestation verification passed for $primary"

From 89bda3b7b63fea7b41bba491c1b85a89edfe5db4 Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 09:46:18 +0200
Subject: [PATCH 2/7] Add M0.9 attestation verification workflow

---
 .../workflows/attestation-verification.yml    | 66 +++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 .github/workflows/attestation-verification.yml

diff --git a/.github/workflows/attestation-verification.yml b/.github/workflows/attestation-verification.yml
new file mode 100644
index 0000000..a53c50e
--- /dev/null
+++ b/.github/workflows/attestation-verification.yml
@@ -0,0 +1,66 @@
+name: Attestation verification
+
+on:
+  pull_request:
+  push:
+    tags:
+      - 'v*'
+  workflow_dispatch:
+    inputs:
+      version:
+        description: Existing release version to verify (for example 0.2.1 or v0.2.1)
+        required: true
+        default: '0.2.1'
+        type: string
+
+permissions:
+  contents: read
+  packages: read
+
+concurrency:
+  group: attestation-verification-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  IMAGE: ghcr.io/ploos-as/glowing-bear
+
+jobs:
+  validate-script:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Validate M0.9 script syntax
+        run: bash -n scripts/qualify_attestations.sh
+
+  verify-attestations:
+    needs: validate-script
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Log in to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Select release version
+        id: release
+        shell: bash
+        run: |
+          set -euo pipefail
+          if [[ "${{ github.event_name }}" == "workflow_dispatch" ]]; then
+            version="${{ inputs.version }}"
+          elif [[ "${GITHUB_REF_TYPE}" == "tag" ]]; then
+            version="${GITHUB_REF_NAME}"
+          else
+            version="0.2.1"
+          fi
+          echo "version=$version" >> "$GITHUB_OUTPUT"
+      - name: Verify published provenance and SBOM attestations
+        env:
+          VERSION: ${{ steps.release.outputs.version }}
+        run: bash scripts/qualify_attestations.sh

From f8c550f1538e1ba266f44c3e507c641c61531e4e Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 09:46:29 +0200
Subject: [PATCH 3/7] Document M0.9 attestation verification

---
 docs/M0_9_ATTESTATION_VERIFICATION.md | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 docs/M0_9_ATTESTATION_VERIFICATION.md

diff --git a/docs/M0_9_ATTESTATION_VERIFICATION.md b/docs/M0_9_ATTESTATION_VERIFICATION.md
new file mode 100644
index 0000000..3e8bea2
--- /dev/null
+++ b/docs/M0_9_ATTESTATION_VERIFICATION.md
@@ -0,0 +1,18 @@
+# M0.9 attestation verification
+
+M0.8 verifies that a published release exposes Buildx attestation manifests. M0.9 strengthens that contract by validating how those attestations are attached and what predicate types they advertise.
+
+For every required Linux platform manifest (`linux/amd64` and `linux/arm64`), M0.9 requires:
+
+- a BuildKit attestation manifest whose `vnd.docker.reference.digest` points to that exact platform digest;
+- `vnd.docker.reference.type=attestation-manifest`;
+- in-toto layers using media type `application/vnd.in-toto+json`;
+- a non-empty SLSA provenance descriptor with predicate type `https://slsa.dev/provenance/v0.2`;
+- a non-empty SPDX SBOM descriptor with predicate type `https://spdx.dev/Document`;
+- sha256 layer digests for both descriptors.
+
+This closes the M0.8 gap where merely counting `unknown/unknown` manifests could not distinguish the required provenance/SBOM contract from unrelated attestations.
+
+The workflow runs on release tags and can also be run manually against an existing immutable release. Pull requests verify the currently published `0.2.1` release as a real registry-backed integration test while also syntax-checking the script.
+
+M0.9 does not claim cryptographic signer identity verification. Signature policy and keyless identity verification, if desired, belong in a later milestone rather than being conflated with attestation-content qualification.

From 7b214dd5842c5fb07c4bd1896326f15f12ae8210 Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 09:47:50 +0200
Subject: [PATCH 4/7] Fix M0.9 attestation descriptor scope

---
 scripts/qualify_attestations.sh | 17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

diff --git a/scripts/qualify_attestations.sh b/scripts/qualify_attestations.sh
index eed2536..bbe2a65 100644
--- a/scripts/qualify_attestations.sh
+++ b/scripts/qualify_attestations.sh
@@ -35,15 +35,18 @@ if [[ "${#platform_digests[@]}" -lt 2 ]]; then
   exit 1
 fi
 
+# BuildKit stores the subject linkage on the attestation descriptor in the OCI
+# index, not inside the attestation manifest itself.
 attestation_rows="$workdir/attestations.tsv"
 jq -r '.manifests[]
   | select(.platform.os == "unknown" and .platform.architecture == "unknown")
   | select(.annotations["vnd.docker.reference.type"] == "attestation-manifest")
+  | select((.annotations["vnd.docker.reference.digest"] // "") | test("^sha256:[0-9a-f]{64}$"))
   | [.digest, .annotations["vnd.docker.reference.digest"]] | @tsv' \
   "$index_json" > "$attestation_rows"
 
 if [[ ! -s "$attestation_rows" ]]; then
-  echo "$primary has no BuildKit attestation manifests" >&2
+  echo "$primary has no valid BuildKit attestation descriptors" >&2
   exit 1
 fi
 
@@ -57,18 +60,6 @@ for platform_digest in "${platform_digests[@]}"; do
   manifest_json="$workdir/${attestation_digest#sha256:}.json"
   docker buildx imagetools inspect --raw "$IMAGE@$attestation_digest" > "$manifest_json"
 
-  linked_digest="$(jq -r '.annotations["vnd.docker.reference.digest"] // empty' "$manifest_json")"
-  reference_type="$(jq -r '.annotations["vnd.docker.reference.type"] // empty' "$manifest_json")"
-
-  if [[ "$linked_digest" != "$platform_digest" ]]; then
-    echo "attestation $attestation_digest links to $linked_digest, expected $platform_digest" >&2
-    exit 1
-  fi
-  if [[ "$reference_type" != "attestation-manifest" ]]; then
-    echo "unexpected attestation reference type for $attestation_digest: $reference_type" >&2
-    exit 1
-  fi
-
   jq -e '[.layers[] | select(.mediaType == "application/vnd.in-toto+json")] | length >= 2' \
     "$manifest_json" >/dev/null || {
       echo "attestation $attestation_digest does not contain the expected in-toto layers" >&2

From ba8c0546044c1dab3b50d7a74d62aa7ce6f604a5 Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 10:01:29 +0200
Subject: [PATCH 5/7] Read M0.9 attestation payloads via Buildx

---
 scripts/qualify_attestations.sh | 91 ++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 41 deletions(-)

diff --git a/scripts/qualify_attestations.sh b/scripts/qualify_attestations.sh
index bbe2a65..cef547e 100644
--- a/scripts/qualify_attestations.sh
+++ b/scripts/qualify_attestations.sh
@@ -20,23 +20,23 @@ trap 'rm -rf "$workdir"' EXIT
 index_json="$workdir/index.json"
 docker buildx imagetools inspect --raw "$primary" > "$index_json"
 
-platform_digests=()
-while IFS= read -r digest; do
-  [[ -n "$digest" ]] && platform_digests+=("$digest")
-done < <(
-  jq -r '.manifests[]
-    | select(.platform.os == "linux")
-    | select(.platform.architecture == "amd64" or .platform.architecture == "arm64")
-    | .digest' "$index_json"
-)
-
-if [[ "${#platform_digests[@]}" -lt 2 ]]; then
-  echo "$primary does not expose both required Linux platform manifests" >&2
-  exit 1
-fi
+platform_rows="$workdir/platforms.tsv"
+jq -r '.manifests[]
+  | select(.platform.os == "linux")
+  | select(.platform.architecture == "amd64" or .platform.architecture == "arm64")
+  | [.platform.architecture, .digest] | @tsv' "$index_json" > "$platform_rows"
+
+for arch in amd64 arm64; do
+  if ! awk -F '\t' -v a="$arch" '$1 == a {found=1} END {exit !found}' "$platform_rows"; then
+    echo "$primary is missing linux/$arch" >&2
+    exit 1
+  fi
+done
 
 # BuildKit stores the subject linkage on the attestation descriptor in the OCI
-# index, not inside the attestation manifest itself.
+# index. The attestation payload itself is exposed by Buildx through the
+# Provenance and SBOM formatter objects; predicate metadata is part of that
+# payload and is not required to be duplicated as a layer annotation.
 attestation_rows="$workdir/attestations.tsv"
 jq -r '.manifests[]
   | select(.platform.os == "unknown" and .platform.architecture == "unknown")
@@ -50,43 +50,52 @@ if [[ ! -s "$attestation_rows" ]]; then
   exit 1
 fi
 
-for platform_digest in "${platform_digests[@]}"; do
+while IFS=$'\t' read -r arch platform_digest; do
   attestation_digest="$(awk -F '\t' -v d="$platform_digest" '$2 == d {print $1; exit}' "$attestation_rows")"
   if [[ -z "$attestation_digest" ]]; then
-    echo "missing attestation manifest for platform digest $platform_digest" >&2
+    echo "missing attestation manifest for linux/$arch digest $platform_digest" >&2
     exit 1
   fi
 
-  manifest_json="$workdir/${attestation_digest#sha256:}.json"
+  manifest_json="$workdir/${attestation_digest#sha256:}.manifest.json"
   docker buildx imagetools inspect --raw "$IMAGE@$attestation_digest" > "$manifest_json"
 
-  jq -e '[.layers[] | select(.mediaType == "application/vnd.in-toto+json")] | length >= 2' \
+  jq -e '[.layers[] | select(.mediaType == "application/vnd.in-toto+json") | select(.size > 0) | .digest | select(test("^sha256:[0-9a-f]{64}$"))] | length >= 2' \
     "$manifest_json" >/dev/null || {
-      echo "attestation $attestation_digest does not contain the expected in-toto layers" >&2
+      echo "attestation $attestation_digest does not contain at least two valid in-toto layers" >&2
       exit 1
     }
 
-  jq -e '.layers[]
-    | select(.mediaType == "application/vnd.in-toto+json")
-    | select(.annotations["in-toto.io/predicate-type"] == "https://slsa.dev/provenance/v0.2")
-    | select(.size > 0)
-    | .digest | test("^sha256:[0-9a-f]{64}$")' \
-    "$manifest_json" >/dev/null || {
-      echo "attestation $attestation_digest is missing a valid SLSA provenance descriptor" >&2
-      exit 1
-    }
-
-  jq -e '.layers[]
-    | select(.mediaType == "application/vnd.in-toto+json")
-    | select(.annotations["in-toto.io/predicate-type"] == "https://spdx.dev/Document")
-    | select(.size > 0)
-    | .digest | test("^sha256:[0-9a-f]{64}$")' \
-    "$manifest_json" >/dev/null || {
-      echo "attestation $attestation_digest is missing a valid SPDX SBOM descriptor" >&2
-      exit 1
-    }
+  provenance_json="$workdir/${arch}.provenance.json"
+  sbom_json="$workdir/${arch}.sbom.json"
+
+  docker buildx imagetools inspect \
+    --format '{{ json .Provenance }}' \
+    "$IMAGE@$platform_digest" > "$provenance_json"
+  docker buildx imagetools inspect \
+    --format '{{ json .SBOM }}' \
+    "$IMAGE@$platform_digest" > "$sbom_json"
+
+  jq -e '
+    . != null and
+    ([.. | objects | .predicateType? // empty]
+      | any(. == "https://slsa.dev/provenance/v0.2" or startswith("https://slsa.dev/provenance/")))
+  ' "$provenance_json" >/dev/null || {
+    echo "linux/$arch is missing readable SLSA provenance content" >&2
+    cat "$provenance_json" >&2 || true
+    exit 1
+  }
+
+  jq -e '
+    . != null and
+    ([.. | objects | .spdxVersion? // empty] | any(startswith("SPDX-")))
+  ' "$sbom_json" >/dev/null || {
+    echo "linux/$arch is missing readable SPDX SBOM content" >&2
+    cat "$sbom_json" >&2 || true
+    exit 1
+  }
 
-  echo "Qualified SLSA provenance and SPDX SBOM for $platform_digest via $attestation_digest"
-done
+  echo "Qualified SLSA provenance and SPDX SBOM for linux/$arch $platform_digest via $attestation_digest"
+done < "$platform_rows"
 
 echo "M0.9 attestation verification passed for $primary"

From d5fccd30076f731d57267b6d413f9dee3c9348f8 Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 10:02:43 +0200
Subject: [PATCH 6/7] Inspect M0.9 payloads from release index

---
 scripts/qualify_attestations.sh | 69 ++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 32 deletions(-)

diff --git a/scripts/qualify_attestations.sh b/scripts/qualify_attestations.sh
index cef547e..c80bf1a 100644
--- a/scripts/qualify_attestations.sh
+++ b/scripts/qualify_attestations.sh
@@ -34,9 +34,9 @@ for arch in amd64 arm64; do
 done
 
 # BuildKit stores the subject linkage on the attestation descriptor in the OCI
-# index. The attestation payload itself is exposed by Buildx through the
-# Provenance and SBOM formatter objects; predicate metadata is part of that
-# payload and is not required to be duplicated as a layer annotation.
+# index. The descriptor binds each attestation manifest to its exact platform
+# digest; Buildx exposes the decoded provenance/SBOM payloads from the parent
+# multi-platform release reference.
 attestation_rows="$workdir/attestations.tsv"
 jq -r '.manifests[]
   | select(.platform.os == "unknown" and .platform.architecture == "unknown")
@@ -66,36 +66,41 @@ while IFS=$'\t' read -r arch platform_digest; do
       exit 1
     }
 
-  provenance_json="$workdir/${arch}.provenance.json"
-  sbom_json="$workdir/${arch}.sbom.json"
-
-  docker buildx imagetools inspect \
-    --format '{{ json .Provenance }}' \
-    "$IMAGE@$platform_digest" > "$provenance_json"
-  docker buildx imagetools inspect \
-    --format '{{ json .SBOM }}' \
-    "$IMAGE@$platform_digest" > "$sbom_json"
-
-  jq -e '
-    . != null and
-    ([.. | objects | .predicateType? // empty]
-      | any(. == "https://slsa.dev/provenance/v0.2" or startswith("https://slsa.dev/provenance/")))
-  ' "$provenance_json" >/dev/null || {
-    echo "linux/$arch is missing readable SLSA provenance content" >&2
-    cat "$provenance_json" >&2 || true
-    exit 1
-  }
-
-  jq -e '
-    . != null and
-    ([.. | objects | .spdxVersion? // empty] | any(startswith("SPDX-")))
-  ' "$sbom_json" >/dev/null || {
-    echo "linux/$arch is missing readable SPDX SBOM content" >&2
-    cat "$sbom_json" >&2 || true
-    exit 1
-  }
+done < "$platform_rows"
+
+provenance_json="$workdir/provenance.json"
+sbom_json="$workdir/sbom.json"
+
+docker buildx imagetools inspect \
+  --format '{{ json .Provenance }}' \
+  "$primary" > "$provenance_json"
+docker buildx imagetools inspect \
+  --format '{{ json .SBOM }}' \
+  "$primary" > "$sbom_json"
+
+jq -e '
+  . != null and
+  ([.. | objects | .predicateType? // empty]
+    | any(. == "https://slsa.dev/provenance/v0.2" or startswith("https://slsa.dev/provenance/")))
+' "$provenance_json" >/dev/null || {
+  echo "$primary is missing readable SLSA provenance content" >&2
+  cat "$provenance_json" >&2 || true
+  exit 1
+}
+
+jq -e '
+  . != null and
+  ([.. | objects | .spdxVersion? // empty] | any(startswith("SPDX-")))
+' "$sbom_json" >/dev/null || {
+  echo "$primary is missing readable SPDX SBOM content" >&2
+  cat "$sbom_json" >&2 || true
+  exit 1
+}
 
-  echo "Qualified SLSA provenance and SPDX SBOM for linux/$arch $platform_digest via $attestation_digest"
+while IFS=$'\t' read -r arch platform_digest; do
+  attestation_digest="$(awk -F '\t' -v d="$platform_digest" '$2 == d {print $1; exit}' "$attestation_rows")"
+  echo "Qualified attestation linkage for linux/$arch $platform_digest via $attestation_digest"
 done < "$platform_rows"
 
+echo "Qualified decoded SLSA provenance and SPDX SBOM payloads for $primary"
 echo "M0.9 attestation verification passed for $primary"

From 1b9a376e1c43fb478d6e24d14a912ab5914dd8d3 Mon Sep 17 00:00:00 2001
From: pos <pgousdal@users.noreply.github.com>
Date: Sat, 5 Sep 2026 10:57:13 +0200
Subject: [PATCH 7/7] Validate Buildx SLSA provenance structure

---
 scripts/qualify_attestations.sh | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/scripts/qualify_attestations.sh b/scripts/qualify_attestations.sh
index c80bf1a..9210b96 100644
--- a/scripts/qualify_attestations.sh
+++ b/scripts/qualify_attestations.sh
@@ -35,7 +35,7 @@ done
 
 # BuildKit stores the subject linkage on the attestation descriptor in the OCI
 # index. The descriptor binds each attestation manifest to its exact platform
-# digest; Buildx exposes the decoded provenance/SBOM payloads from the parent
+# digest; Buildx exposes decoded provenance/SBOM payloads from the parent
 # multi-platform release reference.
 attestation_rows="$workdir/attestations.tsv"
 jq -r '.manifests[]
@@ -65,7 +65,6 @@ while IFS=$'\t' read -r arch platform_digest; do
       echo "attestation $attestation_digest does not contain at least two valid in-toto layers" >&2
       exit 1
     }
-
 done < "$platform_rows"
 
 provenance_json="$workdir/provenance.json"
@@ -78,15 +77,20 @@ docker buildx imagetools inspect \
   --format '{{ json .SBOM }}' \
   "$primary" > "$sbom_json"
 
-jq -e '
-  . != null and
-  ([.. | objects | .predicateType? // empty]
-    | any(. == "https://slsa.dev/provenance/v0.2" or startswith("https://slsa.dev/provenance/")))
-' "$provenance_json" >/dev/null || {
-  echo "$primary is missing readable SLSA provenance content" >&2
-  cat "$provenance_json" >&2 || true
-  exit 1
-}
+for arch in amd64 arm64; do
+  jq -e --arg platform "linux/$arch" '
+    .[$platform].SLSA
+    | type == "object"
+      and (.buildDefinition | type == "object")
+      and (.buildDefinition.buildType | type == "string" and length > 0)
+      and (.runDetails | type == "object")
+      and (.runDetails.builder.id | type == "string" and length > 0)
+  ' "$provenance_json" >/dev/null || {
+    echo "$primary is missing readable SLSA provenance content for linux/$arch" >&2
+    cat "$provenance_json" >&2 || true
+    exit 1
+  }
+done
 
 jq -e '
   . != null and