feat: implement kernel / initrd oci image support (#103)

* feat: implement kernel / initrd oci image support

* fix: implement image urls more faithfully

crates/oci/src/packer/cache.rs

@@ -159,7 +159,9 @@ impl OciPackerCache {
         let image_name = packed.name.to_string();
         annotations.insert(ANNOTATION_IMAGE_NAME.to_string(), image_name);
         let image_ref = packed.name.reference.clone();
-        annotations.insert(ANNOTATION_REF_NAME.to_string(), image_ref);
+        if let Some(image_ref) = image_ref {
+            annotations.insert(ANNOTATION_REF_NAME.to_string(), image_ref);
+        }
         descriptor.set_annotations(Some(annotations));
         manifests.push(descriptor.clone());
         index.set_manifests(manifests);

crates/oci/src/packer/service.rs

@@ -61,6 +61,10 @@ impl OciPackerService {
         digest: &str,
         format: OciPackedFormat,
     ) -> Result<Option<OciPackedImage>> {
+        if digest.contains('/') || digest.contains('\\') || digest.contains("..") {
+            return Ok(None);
+        }
+
         self.cache
             .recall(ImageName::parse("cached:latest")?, digest, format)
             .await