drop platform/digest pull resolution

The digest-pull logic was added to make `docker push` work for multi-arch
upstream tags. Now that the push step is `docker buildx imagetools create`
pinned to the gpg-verified RepoDigest, the registry-to-registry copy
handles single- and multi-arch sources without help. Reverts the pull
back to the original line and removes the unused PLATFORM_OS/_ARCH
detection.

salt/common/tools/sbin/so-image-common

@@ -104,16 +104,6 @@ update_docker_containers() {
   set_version
   set_os
 
-  # Resolve the local Docker daemon's platform once. Used below to pick the
-  # matching sub-manifest from a multi-arch image index — Docker 29.x will not
-  # push a tag that points at an index unless every referenced sub-manifest's
-  # content is present locally.
-  local PLATFORM_OS PLATFORM_ARCH
-  PLATFORM_OS=$(docker version --format '{{.Server.Os}}' 2>/dev/null)
-  PLATFORM_ARCH=$(docker version --format '{{.Server.Arch}}' 2>/dev/null)
-  PLATFORM_OS=${PLATFORM_OS:-linux}
-  PLATFORM_ARCH=${PLATFORM_ARCH:-amd64}
-
   if [ -z "$TRUSTED_CONTAINERS" ]; then
     container_list
   fi
@@ -171,37 +161,11 @@ update_docker_containers() {
       local image=$i:$VERSION$IMAGE_TAG_SUFFIX
       local sig_url=https://sigs.securityonion.net/$VERSION/$image.sig
     fi
-    # Pull down the trusted docker image. If the upstream tag is a multi-arch
+    # Pull down the trusted docker image
-    # image index, resolve the local-platform manifest digest and pull by
+    run_check_net_err \
-    # digest so the local tag points at a single-arch image (not an index).
+    "docker pull $CONTAINER_REGISTRY/$IMAGEREPO/$image" \
-    # That keeps Docker 29.x's index-aware push from trying to push sub-manifests
+    "Could not pull $image, please ensure connectivity to $CONTAINER_REGISTRY" >> "$LOG_FILE" 2>&1
-    # whose content we never fetched.
-    local FULL_IMAGE="$CONTAINER_REGISTRY/$IMAGEREPO/$image"
-    local PLATFORM_DIGEST
-    PLATFORM_DIGEST=$(docker buildx imagetools inspect --raw "$FULL_IMAGE" 2>/dev/null \
-                      | jq -r --arg os "$PLATFORM_OS" --arg arch "$PLATFORM_ARCH" '
-                          .manifests[]?
-                          | select(.platform.os == $os
-                                   and .platform.architecture == $arch
-                                   and ((.platform.variant // "") == "")
-                                   and ((.annotations["vnd.docker.reference.type"] // "") != "attestation-manifest"))
-                          | .digest' 2>/dev/null \
-                      | head -n 1)
 
-    if [ -n "$PLATFORM_DIGEST" ] && [ "$PLATFORM_DIGEST" != "null" ]; then
-      run_check_net_err \
-      "docker pull $FULL_IMAGE@$PLATFORM_DIGEST" \
-      "Could not pull $image ($PLATFORM_OS/$PLATFORM_ARCH), please ensure connectivity to $CONTAINER_REGISTRY" >> "$LOG_FILE" 2>&1
-      docker tag "$FULL_IMAGE@$PLATFORM_DIGEST" "$FULL_IMAGE" >> "$LOG_FILE" 2>&1 || {
-        echo "Unable to retag $image to canonical tag" >> "$LOG_FILE" 2>&1
-        exit 1
-      }
-    else
-      run_check_net_err \
-      "docker pull $FULL_IMAGE" \
-      "Could not pull $image, please ensure connectivity to $CONTAINER_REGISTRY" >> "$LOG_FILE" 2>&1
-    fi
-    
     # Get signature
     run_check_net_err \
     "curl --retry 5 --retry-delay 60 -A '$CURLTYPE/$CURRENTVERSION/$OS/$(uname -r)' $sig_url --output $SIGNPATH/$image.sig" \
@@ -233,11 +197,15 @@ update_docker_containers() {
         # represents freshly-pulled images as an index whose layer content
         # isn't reachable through the push path. The local `docker tag` above
         # is preserved so so-image-pull's `:5000` existence check still works.
-        local PUSH_SRC="$CONTAINER_REGISTRY/$IMAGEREPO/$image"
+        # Pin to the digest already gpg-verified above so we copy exactly the
-        if [ -n "$PLATFORM_DIGEST" ] && [ "$PLATFORM_DIGEST" != "null" ]; then
+        # bytes we approved.
-          PUSH_SRC="$CONTAINER_REGISTRY/$IMAGEREPO/$image@$PLATFORM_DIGEST"
+        local VERIFIED_REF
+        VERIFIED_REF=$(echo "$DOCKERINSPECT" | jq -r ".[0].RepoDigests[] | select(. | contains(\"$CONTAINER_REGISTRY\"))" | head -n 1)
+        if [ -z "$VERIFIED_REF" ] || [ "$VERIFIED_REF" = "null" ]; then
+          echo "Unable to determine verified digest for $image" >> "$LOG_FILE" 2>&1
+          exit 1
         fi
-        docker buildx imagetools create --tag $HOSTNAME:5000/$IMAGEREPO/$image "$PUSH_SRC" >> "$LOG_FILE" 2>&1 || {
+        docker buildx imagetools create --tag $HOSTNAME:5000/$IMAGEREPO/$image "$VERIFIED_REF" >> "$LOG_FILE" 2>&1 || {
           echo "Unable to copy $image to embedded registry" >> "$LOG_FILE" 2>&1
           exit 1
         }