Relationships / Dependencies are present in Syft json and SPDX json files but sometimes not in Cyclonedx json file format about syft

[tgerla]

Thanks @haiazuki for the report! We will take a look. This issue is possibly related to: #2353 and #2305

[tgerla]

Dev notes: there are some format limitations in CycloneDX that prevent us from representing every relationship that we handle in other formats like SPDX, so there will always be some functionality differences between the various formats. We could probably encode CONTAINS and DEPENDS-ON relationships in CycloneDX, though. The challenge encoding the CONTAINS relationship is that it requires nesting components in CycloneDX which we aren't currently doing--it wouldn't be expressible in the dependency relationships.

@haiazuki, if you are able, can you share a bit more about your use case and needs here? Are you looking for a source code dependency tree or something similar? More details might be helpful for us to look into this. Thanks!

[haiazuki]

Hi @tgerla ,
I checked the specifications of SPDX compare with CycloneDX so I understand what you are saying. From a CycloneDX perspective, it tracks dependency relationships so DEPENDS-ON seem to be the priority.
In the product I am testing with, I have an installer in a jar package that I used as the target source to generate the sbom. This contains other jar files and also a war file that contains other jar file packages. So I was looking for entries that reflect the relationship of these packages similar to what is in default json and spdx json.

Thank you!

[flemminglau]

I see syft producing usable Cyclonedx dependency information for image scans except from the tiny detail described here: DependencyTrack/dependency-track#3314

I have tried manually adding the missing dependency between the root object and some random set of modules and then DT can show a dependency tree for that part. It seems DT doesn't even try to build a dependency tree when the root dependency is missing. Probably because it doesn't know where to start.

Is there a good reason this has not been fixed already (or why the issue has ever arisen)?

[haiazuki]

Shouldn't this need to be included in milestone "Meet NTIA Minimum SBOM Requirements" as relationships are part of the minimum elements in NTIA?

[spiffcs]

👋 I think it would be useful for this issue if we could posting specific examples of where dependencies should exist in cyclone-dx and they are not showing up. Syft currently uses the dependencies field of cyclone dx to represent depends-on as found by spdx.

Are there other sections we should be putting non dependency relationship information?
In the SBOM you are generating what data is not showing up in the cyclonedx dependencies section that you expect to show up?

A good example of the format I'm looking for to help the discussion is something like this:

I am using syft v1.6.0 to scan `alpine:latest`

Here are the commands I'm running:

 syft -o spdx-json alpine:latest | jq . > spdx.json
 syft -o cyclonedx-json alpine:latest | jq . > cdx.json

In spdx.json I see:

    {
      "spdxElementId": "SPDXRef-Package-apk-musl-03e521237cbed45a",
      "relatedSpdxElement": "SPDXRef-File-lib-ld-musl-aarch64.so.1-15ac5a87021c605c",
      "relationshipType": "CONTAINS"
    },

These contains relationships are not shown in cyclone-dx.

All I see in cyclone-dx are the depends on relationships - here is an example:

    {
      "ref": "pkg:apk/alpine/[email protected]?arch=aarch64&upstream=openssl&distro=alpine-3.20.0&package-id=0cfcda1a242dfd13",
      "dependsOn": [
        "pkg:apk/alpine/[email protected]?arch=aarch64&distro=alpine-3.20.0&package-id=03e521237cbed45a"
      ]
    },