nikolay / rbac-tool

Kubernetes RBAC Power Toys - Visualize, Generate & Query

Kubernetes RBAC

Role-based access control (RBAC) is a method of regulating access to computer or network resources based on the roles of individual users within your organization. RBAC authorization uses the rbac.authorization.k8s.io API group to drive authorization decisions, allowing you to dynamically configure policies through the Kubernetes API.

Permissions are purely additive (there are no “deny” rules).

A Role always sets permissions within a particular namespace ; when you create a Role, you have to specify the namespace it belongs in. ClusterRole, by contrast, is a non-namespaced resource. ClusterRoles have several uses. You can use a ClusterRole to:

• define permissions on namespaced resources and be granted within individual namespace(s)
• define permissions on namespaced resources and be granted across all namespaces
• define permissions on cluster-scoped resources

If you want to define a role within a namespace, use a Role; if you want to define a role cluster-wide, use a ClusterRole.

rbac-tool simplifies querying and creation RBAC policies.

Install

Download the latest from the release page

curl https://raw.githubusercontent.com/alcideio/rbac-tool/master/download.sh | bash

rbac-tool

A collection of Kubernetes RBAC tools to sugar coat Kubernetes RBAC complexity

Usage:
  rbac-tool [command]

Available Commands:
  auditgen        Generate from Kubernetes audit events, RBAC policy
  bash-completion Generate bash completion. source < (advisor bash-completion)
  generate        Generate Role or ClusterRole and reduce the use of wildcards
  help            Help about any command
  lookup          RBAC Lookup by subject (user/group/serviceaccount) name
  policy-rules    RBAC List Policy Rules For subject (user/group/serviceaccount) name
  version         Print rbac-tool version
  visualize       A RBAC visualizer

Flags:
  -h, --help      help for rbac-tool
  -v, --v Level   number for the log level verbosity

• The rbac-tool viz command
• The rbac-tool lookup command
• The rbac-tool policy-rules command
• The rbac-tool auditgen command
• The rbac-tool gen command
• Command Line Reference
• Contributing

rbac-tool viz

A Kubernetes RBAC visualizer that generate a graph as dot file format or in HTML format.

By default 'rbac-tool viz' will connect to the local cluster (pointed by kubeconfig) Create a RBAC graph of the actively running workload on all namespaces except kube-system

See run options on how to render specific namespaces, other clusters, etc.

#Render Locally
rbac-tool viz --outformat dot && cat rbac.dot | dot -Tpng > rbac.png  && open rbac.png

# Render Online
https://dreampuf.github.io/GraphvizOnline

Examples:

# Scan the cluster pointed by the kubeconfig context 'myctx'
rbac-tool viz --cluster-context myctx

# Scan and create a PNG image from the graph
rbac-tool viz --outformat dot --exclude-namespaces=soemns && cat rbac.dot | dot -Tpng > rbac.png && google-chrome rbac.png

rbac-tool lookup

Lookup of the Roles/ClusterRoles used attached to User/ServiceAccount/Group with or without regex

Examples:

# Search All Service Accounts
rbac-tool lookup -e '.*'

# Search All Service Accounts That Contains myname
rbac-tool lookup -e '.*myname.*'

rbac-tool lookup -e '^system:'
  SUBJECT                                         | SUBJECT TYPE | SCOPE       | NAMESPACE   | ROLE                                                                  
+-------------------------------------------------+--------------+-------------+-------------+----------------------------------------------------------------------+
  system:anonymous                                | User         | Role        | kube-public | kubeadm:bootstrap-signer-clusterinfo                                  
  system:authenticated                            | Group        | ClusterRole |             | system:discovery                                                      
  system:authenticated                            | Group        | ClusterRole |             | system:public-info-viewer                                             
  system:authenticated                            | Group        | ClusterRole |             | system:basic-user                                                     
  system:bootstrappers:kubeadm:default-node-token | Group        | ClusterRole |             | system:certificates.k8s.io:certificatesigningrequests:nodeclient      
  system:bootstrappers:kubeadm:default-node-token | Group        | ClusterRole |             | system:node-bootstrapper                                              
  system:bootstrappers:kubeadm:default-node-token | Group        | Role        | kube-system | kubeadm:nodes-kubeadm-config                                          
  system:bootstrappers:kubeadm:default-node-token | Group        | Role        | kube-system | kubeadm:kubelet-config-1.16                                           
  system:bootstrappers:kubeadm:default-node-token | Group        | Role        | kube-system | kube-proxy                                                            
  system:kube-controller-manager                  | User         | ClusterRole |             | system:kube-controller-manager       
...

rbac-tool policy-rules

List Kubernetes RBAC policy rules for a given User/ServiceAccount/Group with or without regex

Examples:

# List policy rules for system unauthenicated group
rbac-tool policy-rules -e '^system:unauth'

Output:

  TYPE  | SUBJECT                | VERBS | NAMESPACE | API GROUP | KIND | NAMES | NONRESOURCEURI                              
+-------+------------------------+-------+-----------+-----------+------+-------+--------------------------------------------+
  Group | system:unauthenticated | get   | *         | -         | -    | -     | /healthz,/livez,/readyz,/version,/version/  

Leveraging JMESPath to filter and transform RBAC Policy rules.

For example: Who Can Read Secrets

rbac-tool policy-rules -o json  | jp "[? @.allowedTo[? (verb=='get' || verb=='*') && (apiGroup=='core' || apiGroup=='*') && (resource=='secrets' || resource == '*')  ]].{name: name, namespace: namespace, kind: kind}"

See https://jmespath.org/

rbac-tool auditgen

Generate RBAC policy from Kubernetes audit events. Audit source format can be:

• Kubernetes List Object that contains Audit Events
• Newline seperated Audit Event objects Audit source can be file, directory or http URL.

rbac-tool auditgen -f audit.log

This command is based on this prior work.

rbac-tool gen

Examples would be simplest way to describe how rbac-tool gen can help:

• Generate a ClusterRole policy that allows to read everything except secrets and services
• Generate a Role policy that allows create,update,get,list (read/write) everything except secrets, services, ingresses, networkpolicies
• Generate a Role policy that allows create,update,get,list (read/write) everything except statefulsets

rbac-tool generate RBAC Role or RBAC ClusterRole resource while reducing the use of wildcards, and support deny semantics for specific Kubernetes clusters.

How rbac-tool gen works?

rbac-tool reads from the Kubernetes discovery API the available API Groups and resources, which represents the "world" of resources. Based on the command line options, generate an explicit Role/ClusterRole that avoid wildcards by expanding wildcards to the available "world" resources.

Command Line Examples

Examples generated against Kubernetes cluster v1.16 deployed using KIND.

Generate a ClusterRole policy that allows to read everything except secrets and services

rbac-tool  gen  --deny-resources=secrets.,services. --allowed-verbs=get,list

Generate a Role policy that allows create,update,get,list (read/write) everything except secrets, services, networkpolicies in core,apps & networking.k8s.io API groups

rbac-tool  gen --generated-type=Role --deny-resources=secrets.,services.,networkpolicies.networking.k8s.io --allowed-verbs=* --allowed-groups=,extensions,apps,networking.k8s.io

Generate a Role policy that allows create,update,get,list (read/write) everything except statefulsets

rbac-tool  gen --generated-type=Role --deny-resources=apps.statefulsets --allowed-verbs=* 

Example Output

Generate a Role policy that allows create,update,get,list (read/write) everything except secrets, services, networkpolicies in core,apps & networking.k8s.io API groups

rbac-tool  gen --generated-type=Role --deny-resources=secrets.,services.,networkpolicies.networking.k8s.io --allowed-verbs=* --allowed-groups=,extensions,apps,networking.k8s.io

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  creationTimestamp: null
  name: custom-role
  namespace: mynamespace
rules:
- apiGroups:
  - ""
  resources:
  - events
  - componentstatuses
  - podtemplates
  - namespaces
  - replicationcontrollers
  - persistentvolumes
  - configmaps
  - persistentvolumeclaims
  - resourcequotas
  - limitranges
  - nodes
  - bindings
  - serviceaccounts
  - pods
  - endpoints
  verbs:
  - '*'
- apiGroups:
  - extensions
  resources:
  - ingresses
  verbs:
  - '*'
- apiGroups:
  - apps
  resources:
  - replicasets
  - daemonsets
  - deployments
  - controllerrevisions
  - statefulsets
  verbs:
  - '*'
- apiGroups:
  - networking.k8s.io
  resources:
  - ingresses
  verbs:
  - '*'

Command Line Reference

Generate Role or ClusterRole resource while reducing the use of wildcards.

rbac-tool read from the Kubernetes discovery API the available API Groups and resources, 
and based on the command line options, generate an explicit Role/ClusterRole that avoid wildcards

Examples:

# Generate a Role with read-only (get,list) excluding secrets (core group) and ingresses (extensions group) 
rbac-tool gen --generated-type=Role --deny-resources=secrets.,ingresses.extensions --allowed-verbs=get,list

# Generate a Role with read-only (get,list) excluding secrets (core group) from core group, admissionregistration.k8s.io,storage.k8s.io,networking.k8s.io
rbac-tool gen --generated-type=ClusterRole --deny-resources=secrets., --allowed-verbs=get,list  --allowed-groups=,admissionregistration.k8s.io,storage.k8s.io,networking.k8s.io

Usage:
  rbac-tool generate [flags]

Aliases:
  generate, gen

Flags:
      --allowed-groups strings   Comma separated list of API groups we would like to allow '*' (default [*])
      --allowed-verbs strings    Comma separated list of verbs to include. To include all use '* (default [*])
  -c, --cluster-context string   Cluster.use 'kubectl config get-contexts' to list available contexts
      --deny-resources strings   Comma separated list of resource.group
  -t, --generated-type string    Role or ClusteRole (default "ClusterRole")
  -h, --help                     help for generate

Contributing

Bugs

If you think you have found a bug please follow the instructions below.

• Please spend a small amount of time giving due diligence to the issue tracker. Your issue might be a duplicate.
• Open a new issue if a duplicate doesn't already exist.

Features

If you have an idea to enhance rbac-tool follow the steps below.

• Open a new issue.
• Remember users might be searching for your issue in the future, so please give it a meaningful title to helps others.
• Clearly define the use case, using concrete examples.
• Feel free to include any technical design for your feature.

Pull Requests

• Your PR is more likely to be accepted if it focuses on just one change.
• Please include a comment with the results before and after your change.
• Your PR is more likely to be accepted if it includes tests.
• You're welcome to submit a draft PR if you would like early feedback on an idea or an approach.