Model Validation Operator does not allow passing trust configuration (--trust_config) for model_signing verification (fails root/targets verification)

[ASWINBABUKV]

Tried verifying a model and signed signature using the Model Validation Operator with my own Sigstore stack (custom Fulcio, Rekor, and Keycloak OIDC provider).

1. I have signed the model using model-signing CLI passing --trust_config=trust-config.json (which contains the details of Fulcio, Rekor, CTlogs and OIDC Provider)
   Cmd Used: model_signing sign sigstore model --trust_config <trust-config.json> --client_id --client_secret "secret"

2. To access the signed model and model signature, uploaded both to a PVC and tried verifying using Model Validation Operator Webhook.

3. Verification by the Model Validation Operator Webhook fails
   Error:
   Key </hash value> failed to verify root
   Key </hash value> failed to verify targets

I couldn't find a way to provide a trust_config or root of trust to the Model Validator Operator.

Currently Operator (apiVersion: ml.sigstore.dev/v1alpha1, kind: ModelValidation) allows only
sigstoreConfig:
certificateIdentity:
certificateOidcIssuer:

Is there a solution to pass this root of trust to the operator?

[miyunari]

I think there is currently no option to bypass this. We may want to add an entry to the CRD to point to a configmap or secret.

e.g.:

apiVersion: ml.sigstore.dev/v1alpha1
kind: ModelValidation
metadata:
  name: demo
spec:
  config:
+    trustConfig:
+        volumes:
+        - name: "example.json"
+          configMap:
+            name: "my-trust-config"
    sigstoreConfig:
      certificateIdentity: "https://github.com/sigstore/model-validation-operator/.github/workflows/sign-model.yaml@refs/tags/v0.0.2"
      certificateOidcIssuer: "https://token.actions.githubusercontent.com"
  model:
    path: /data/tensorflow_saved_model
    signaturePath: /data/tensorflow_saved_model/model.sig

wdyt?

[knrc]

This should be covered by #58. If there's something not already covered then let me know and I can add it.