We'd like to allow our developers to automatically deploy their changes to a kubernetes cluster by merging their code and k8s ressources in a git repo which is watched by ArgoCD. The release management teams would responsible to manage the ArgoCD config and setting up new apps as well as for creation of namespaces, roles and role bindings on the cluster while the devs should be able to deploy their applications through GitOps without the need to interact with the cluster directly. Devs might have read access on the cluster for debugging purposes. Now the question: in theory it would be possible that a dev would create a new yaml and specify a rolebinding ressource, which binds his/her account to a cluster admin role. As ArgoCD has cluster admin rights, this would be a way to escalate privileges for the dev. (or an attacker impersonating a developer) Is there a way to restrict, which k8s ressources are allowed to be created through ArgoCD.
EDIT:
According to the docs, this is possible per project using clusterResourceWhitelist.
Is it possible to do that globally?
You are right about Argo CD project. The project CRD supports allowing/denying K8S resources using clusterResourceWhitelist, clusterResourceBlacklist etc fields. The sample project definition is also available in Argo CD documentation.
In order to restrict the list of managed resources globally, you can specify the resource.exclusions/resource.inclusions field in the argocd-cm ConfigMap. The example is available here.