validation on name for targetRef is too weak

[lahabana]

What happened?

In:

kuma/pkg/plugins/policies/core/matchers/validators/validator.go

Lines 26 to 44 in 29d7e81

	refKind := ref.Kind
	switch refKind {
	case common_api.Mesh:
	if ref.Name != "" {
	verr.AddViolation("name", fmt.Sprintf("using name with kind %v is not yet supported", refKind))
	}
	verr.Add(disallowedField("mesh", ref.Mesh, refKind))
	verr.Add(disallowedField("tags", ref.Tags, refKind))
	case common_api.MeshSubset:
	verr.Add(disallowedField("name", ref.Name, refKind))
	verr.Add(disallowedField("mesh", ref.Mesh, refKind))
	case common_api.MeshService:
	verr.Add(requiredField("name", ref.Name, refKind))
	verr.Add(disallowedField("mesh", ref.Mesh, refKind))
	verr.Add(disallowedField("tags", ref.Tags, refKind))
	case common_api.MeshServiceSubset:
	verr.Add(requiredField("name", ref.Name, refKind))
	verr.Add(disallowedField("mesh", ref.Mesh, refKind))
	}

There's no validation on the value of name, tags, mesh.

For example someone did:

targetRef:
  kind: MeshService
  name: '*'

because they were used to old policies.

[jakubdyszkiewicz]

Triage: reuse validator for service name and tags