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Role-Based Access Control

Role-Based Access Control (RBAC) lets you restrict access to resources and actions to specified users or groups, based on user roles.

How it works

Kong Mesh provides two resources to implement RBAC:

AccessRole specifies kinds of access and resources to which access is granted. Note that access is defined only for write operations. Read access is available to all users.
AccessRoleBinding lists users and the access roles that are assigned to them.

AccessRole

AccessRole defines a role that is assigned separately to users. It is global-scoped, which means it is not bound to a mesh.

Universal

Kubernetes

type: AccessRole
name: role-1
rules:
- types: ["TrafficPermission", "TrafficRoute", "Mesh"] # list of types to which access is granted. If empty, then access is granted to all types
  names: ["res-1"] # list of allowed names of types to which access is granted. If empty, then access is granted to resources regardless of the name.
  mesh: default # Mesh within which the access to resources is granted. It can only be used with the Mesh-scoped resources.
  access: ["CREATE", "UPDATE", "DELETE", "GENERATE_DATAPLANE_TOKEN", "GENERATE_USER_TOKEN", "GENERATE_ZONE_CP_TOKEN"] # an action that is bound to a type.
  when: # a set of qualifiers to receive an access. Only one of them needs to be fulfilled to receive an access
  - sources: # a condition on sources section in connection policies (like TrafficRoute or Healtchecheck). If missing, then all sources are allowed
      match:
        kuma.io/service: web
    destinations: # a condition on destinations section in connection policies (like TrafficRoute or Healtchecheck). If missing, then all destinations are allowed
      match:
        kuma.io/service: backend
  - selectors: # a condition on selectors section in dataplane policies (like TrafficTrace or ProxyTemplate).
      match:
        kuma.io/service: web
  - dpToken: # a condition on generate dataplane token.
      tags:
      - name: kuma.io/service
        value: web

apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: role-1
spec:
  rules:
  - types: ["TrafficPermission", "TrafficRoute", "Mesh"] # list of types to which access is granted. If empty, then access is granted to all types
    names: ["res-1"] # list of allowed names of types to which access is granted. If empty, then access is granted to resources regardless of the name.
    mesh: default # Mesh within which the access to resources is granted. It can only be used with the Mesh-scoped resources.
    access: ["CREATE", "UPDATE", "DELETE", "GENERATE_DATAPLANE_TOKEN", "GENERATE_USER_TOKEN", "GENERATE_ZONE_CP_TOKEN"] # an action that is bound to a type.
    when: # a set of qualifiers to receive an access. Only one of them needs to be fulfilled to receive an access
    - sources: # a condition on sources section in connection policies (like TrafficRoute or Healtchecheck). If missing, then all sources are allowed
        match:
          kuma.io/service: web
      destinations: # a condition on destinations section in connection policies (like TrafficRoute or Healtchecheck). If missing, then all destinations are allowed
        match:
          kuma.io/service: backend
    - selectors: # a condition on selectors section in dataplane policies (like TrafficTrace or ProxyTemplate).
        match:
          kuma.io/service: web
    - dpToken: # a condition on generate dataplane token.
        tags:
        - name: kuma.io/service
          value: web

AccessRoleBinding

AccessRoleBinding assigns a set of AccessRoles to a set of subjects (users and groups). It is global-scoped, which means it is not bound to a mesh.

Universal

Kubernetes

type: AccessRoleBinding
name: binding-1
subjects: # a list of subjects that will be assigned roles
- type: User # type of the subject. Available values: ("User", "Group")
  name: john.doe@example.com # name of the subject.
- type: Group
  name: team-a
roles: # a list of roles that will be assigned to the list of subjects.
- role-1

apiVersion: kuma.io/v1alpha1
kind: AccessRoleBinding
metadata:
  name: binding-1
spec:
  subjects: # a list of subjects that will be assigned roles
  - type: User # type of the subject. Available values: ("User", "Group")
    name: john.doe@example.com # name of the subject.
  - type: Group
    name: team-a
  roles: # a list of roles that will be assigned to the list of subjects.
  - role-1

Example roles

Let’s go through example roles in the organization that can be created using Kong Mesh RBAC.

Kong Mesh operator (admin)

Mesh operator is a part of infrastructure team responsible for Kong Mesh deployment.

Universal

Kubernetes

type: AccessRole
name: admin
rules:
- access: ["CREATE", "UPDATE", "DELETE", "GENERATE_DATAPLANE_TOKEN", "GENERATE_USER_TOKEN", "GENERATE_ZONE_CP_TOKEN"]

apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: admin
spec:
  rules:
  - access: ["CREATE", "UPDATE", "DELETE", "GENERATE_DATAPLANE_TOKEN", "GENERATE_USER_TOKEN", "GENERATE_ZONE_CP_TOKEN"]

This way Kong Mesh operators can execute any action.

Note: this role is created on the start of the control plane.

Service owner

Service owner is a part of team responsible for given service. Let’s take a backend service as an example.

Universal

Kubernetes

type: AccessRole
name: backend-owner
rules:
- mesh: default
  types: ["TrafficPermission", "RateLimit"]
  access: ["CREATE", "DELETE", "UPDATE"]
  when:
  - destinations:
      match:
        kuma.io/service: backend
- mesh: default
  types: ["TrafficRoute", "HealthCheck", "CircuitBreaker", "FaultInjection", "Retry", "Timeout", "TrafficLog"]
  access: ["CREATE", "DELETE", "UPDATE"]
  when:
  - sources:
      match:
        kuma.io/service: backend
  - destinations:
      match:
        kuma.io/service: backend
- mesh: default
  types: ["TrafficTrace", "ProxyTemplate"]
  access: ["CREATE", "DELETE", "UPDATE"]
  when:
  - selectors:
      match:
        kuma.io/service: backend

apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: backend-owner
spec:
  rules:
    - mesh: default
      types: ["TrafficPermission", "RateLimit"]
      access: ["CREATE", "DELETE", "UPDATE"]
      when:
        - destinations:
            match:
              kuma.io/service: backend
    - mesh: default
      types: ["TrafficRoute", "HealthCheck", "CircuitBreaker", "FaultInjection", "Retry", "Timeout", "TrafficLog"]
      access: ["CREATE", "DELETE", "UPDATE"]
      when:
        - sources:
            match:
              kuma.io/service: backend
        - destinations:
            match:
              kuma.io/service: backend
    - mesh: default
      types: ["TrafficTrace", "ProxyTemplate"]
      access: ["CREATE", "DELETE", "UPDATE"]
      when:
        - selectors:
            match:
              kuma.io/service: backend

This way a service owners can:

Modify RateLimit and TrafficPermission that allows/restrict access to the backend service. This changes the configuration of data plane proxy that implements backend service.
Modify connection policies (TrafficRoute, HealthCheck, CircuitBreaker, FaultInjection, Retry, Timeout, RateLimit, TrafficLog) that matches backend service that connects to other services. This changes the configuration of data plane proxy that implements backend service.
Modify connection policies that matches any service that consumes backend service. This changes the configuration of data plane proxies that are connecting to backend, but the configuration only affects connections to backend service. It’s useful because the service owner of backend has the best knowledge what (Timeouts, HealthCheck) should be applied when communicating with their service.
Modify TrafficTrace or ProxyTemplate that matches backend service. This changes the configuration of data plane proxy that implements backend service.

Observability operator

We may also have an infrastructure team which is responsible for the logging/metrics/tracing systems in the organization. Currently, those features are configured on Mesh, TrafficLog and TrafficTrace objects.

Universal

Kubernetes

type: AccessRole
name: observability-operator
rules:
- mesh: '*'
  types: ["TrafficLog", "TrafficTrace"]
  access: ["CREATE", "DELETE", "UPDATE"]
- types: ["Mesh"]
  access: ["CREATE", "DELETE", "UPDATE"]

apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: observability-operator
spec:
  rules:
    - mesh: '*'
      types: ["TrafficLog", "TrafficTrace"]
      access: ["CREATE", "DELETE", "UPDATE"]
    - types: ["Mesh"]
      access: ["CREATE", "DELETE", "UPDATE"]

This way an observability operator can:

Modify TrafficLog and TrafficTrace in any mesh
Modify any Mesh

Single Mesh operator

Kong Mesh lets us segment the deployment into many logical Service Meshes configured by Mesh object. We may want to give an access to one specific Mesh and all objects connected with this Mesh.

Universal

Kubernetes

type: AccessRole
name: demo-mesh-operator
rules:
- mesh: demo
  access: ["CREATE", "DELETE", "UPDATE"]
- types: ["Mesh"]
  names: ["demo"]
  access: ["CREATE", "DELETE", "UPDATE"]

apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: demo-mesh-operator
spec:
  rules:
    - mesh: demo
      access: ["CREATE", "DELETE", "UPDATE"]
    - types: ["Mesh"]
      names: ["demo"]
      access: ["CREATE", "DELETE", "UPDATE"]

This way all observability operator can:

Modify all resources in the demo mesh
Modify demo Mesh object.

Kubernetes

Kubernetes provides their own RBAC system, but it’s not sufficient to cover use cases for several reasons:

You cannot restrict an access to resources of specific Mesh
You cannot restrict an access based on the content of the policy

Kong Mesh RBAC works on top of Kubernetes RBAC. For example, to restrict the access for a user to modify TrafficPermission for backend service, they need to be able to create TrafficPermission in the first place.

The subjects in AccessRoleBinding are compatible with Kubernetes users and groups. Kong Mesh RBAC on Kubernetes is implemented using Kubernetes Webhook when applying resources. This means you can only use Kubernetes users and groups for CREATE, DELETE and UPDATE access. GENERATE_DATAPLANE_TOKEN, GENERATE_USER_TOKEN, GENERATE_ZONE_CP_TOKEN are used when interacting with Kong Mesh API Server, in this case you need to use the user token.

Default

Kong Mesh creates an admin AccessRole that allows every action.

In a standalone deployment, the default AccessRoleBinding assigns this role to every authenticated and unauthenticated user.

In a multi-zone deployment, the default AccessRoleBinding on the global control plane assigns this role to every authenticated and unauthenticated user. However, on the zone control plane, the default AccessRoleBinding is restricted to the admin AccessRole only.

Universal

Kubernetes

type: AccessRole
name: admin
rules:
- access: ["CREATE", "UPDATE", "DELETE", "GENERATE_DATAPLANE_TOKEN", "GENERATE_USER_TOKEN", "GENERATE_ZONE_CP_TOKEN"]
---
type: AccessRoleBinding
name: default
subjects:
- type: Group
  name: mesh-system:authenticated
- type: Group
  name: mesh-system:unauthenticated
roles:
- admin

apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: admin
spec:
  rules:
  - access: ["CREATE", "UPDATE", "DELETE", "GENERATE_DATAPLANE_TOKEN", "GENERATE_USER_TOKEN", "GENERATE_ZONE_CP_TOKEN"]
---
apiVersion: kuma.io/v1alpha1
kind: AccessRoleBinding
metadata:
  name: default
spec:
  subjects:
  - type: Group
    name: mesh-system:authenticated
  - type: Group
    name: mesh-system:unauthenticated
  - type: Group
    name: system:authenticated
  - type: Group
    name: system:unauthenticated
  roles:
  - admin

To restrict access to admin only, change the default AccessRole policy:

Universal

Kubernetes

type: AccessRoleBinding
name: default
subjects:
- type: Group
  name: mesh-system:admin
roles:
- admin

apiVersion: kuma.io/v1alpha1
kind: AccessRoleBinding
metadata:
  name: default
spec:
  subjects:
  - type: Group
    name: mesh-system:admin
  - type: Group
    name: system:masters
  - type: Group
    name: system:serviceaccounts:kube-system
  roles:
  - admin

system:serviceaccounts:kube-system is required for Kubernetes controllers to manage Kuma resources – for example, to remove Dataplane objects when a namespace is removed.

Example

Here are the steps to create a new user and restrict the access only to TrafficPermission for backend service.

Universal

Kubernetes

NOTE By default, all requests that originates from localhost are authenticated as user admin belonging to group mesh-system:admin. In order for this example to work you must either run the control plane with KUMA_API_SERVER_AUTHN_LOCALHOST_IS_ADMIN set to false or be accessing the control plane not via localhost.

Extract admin token and configure kumactl with admin

$ export ADMIN_TOKEN=$(curl http://localhost:5681/global-secrets/admin-user-token | jq -r .data | base64 -d)
$ kumactl config control-planes add \
--name=cp-admin \
--address=https://localhost:5682 \
--skip-verify=true \
--auth-type=tokens \
--auth-conf token=$ADMIN_TOKEN

Configure backend-owner

$ export BACKEND_OWNER_TOKEN=$(kumactl generate user-token --valid-for=24h --name backend-owner)
$ kumactl config control-planes add \
--name=cp-backend-owner \
--address=https://localhost:5682 \
--skip-verify=true \
--auth-type=tokens \
--auth-conf token=$BACKEND_OWNER_TOKEN
$ kumactl config control-planes switch --name cp-admin # switch back to admin

Change default Kong Mesh RBAC to restrict access to resources by default

$ echo "type: AccessRoleBinding
name: default
subjects:
- type: Group
  name: mesh-system:admin
roles:
- admin" | kumactl apply -f -

Create Kong Mesh RBAC to restrict backend-owner to only modify TrafficPermission for backend

$ echo '
type: AccessRole
name: backend-owner
rules:
- types: ["TrafficPermission"]
  mesh: default
  access: ["CREATE", "UPDATE", "DELETE"]
  when:
  - destinations:
      match:
        kuma.io/service: backend
' | kumactl apply -f -
$ echo '
type: AccessRoleBinding
name: backend-owners
subjects:
- type: User
  name: backend-owner
roles:
- backend-owner' | kumactl apply -f -

Change the user and test RBAC

$ kumactl config control-planes switch --name cp-backend-owner
$ echo "
type: TrafficPermission
mesh: default
name: web-to-backend
sources:
- match:
    kuma.io/service: web
destinations:
- match:
    kuma.io/service: backend
" | kumactl apply -f -
# this operation should succeed

$ echo "
type: TrafficPermission
mesh: default
name: web-to-backend
sources:
- match:
    kuma.io/service: web
destinations:
- match:
    kuma.io/service: other
" | kumactl apply -f -
Error: Access Denied (user "backend-owner/mesh-system:authenticated" cannot access the resource)

Create a backend-owner Kubernetes user and configure kubectl

$ mkdir -p /tmp/k8s-certs
$ cd /tmp/k8s-certs
$ openssl genrsa -out backend-owner.key 2048 # generate client key
$ openssl req -new -key backend-owner.key -subj "/CN=backend-owner" -out backend-owner.csr # generate client certificate request
$ CSR=$(cat backend-owner.csr | base64 | tr -d "\n") && echo "apiVersion: certificates.k8s.io/v1
kind: CertificateSigningRequest
metadata:
  name: backend-owner
spec:
  request: $CSR
  signerName: kubernetes.io/kube-apiserver-client
  usages:
  - client auth" | kubectl apply -f -
$ kubectl certificate approve backend-owner
$ kubectl get csr backend-owner -o jsonpath='{.status.certificate}'| base64 -d > backend-owner.crt
$ kubectl config set-credentials backend-owner \
--client-key=/tmp/k8s-certs/backend-owner.key \
--client-certificate=/tmp/k8s-certs/backend-owner.crt \
--embed-certs=true
$ kubectl config set-context backend-owner --cluster=YOUR_CLUSTER_NAME --user=backend-owner

Create Kubernetes RBAC to allow backend-owner to manage all TrafficPermission

$ echo "
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: kuma-policy-management
rules:
- apiGroups:
  - kuma.io
  resources:
  - trafficpermissions
  verbs:
  - get
  - list
  - watch
  - create
  - update
  - patch
  - delete
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kuma-policy-management-backend-owner
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: kuma-policy-management
subjects:
- kind: User
  name: backend-owner
  apiGroup: rbac.authorization.k8s.io
" | kubectl apply -f -

Change default Kong Mesh RBAC to restrict access to resources by default

$ echo "
apiVersion: kuma.io/v1alpha1
kind: AccessRoleBinding
metadata:
  name: default
spec:
  subjects:
  - type: Group
    name: mesh-system:admin
  - type: Group
    name: system:masters
  roles:
  - admin
" | kubectl apply -f -

Create an AccessRole to grant permissions to user backend-owner to modify TrafficPermission only for the backend service:

$ echo "
---
apiVersion: kuma.io/v1alpha1
kind: AccessRole
metadata:
  name: backend-owner
spec:
  rules:
  - types: ["TrafficPermission"]
    mesh: default
    access: ["CREATE", "UPDATE", "DELETE"]
    when:
    - destinations:
        match:
          kuma.io/service: backend
---
apiVersion: kuma.io/v1alpha1
kind: AccessRoleBinding
metadata:
  name: backend-owners
spec:
  subjects:
  - type: User
    name: backend-owner
  roles:
  - backend-owner
" | kubectl apply -f -

Change the service to test user access:

$ kubectl config use-context backend-owner
$ echo "
apiVersion: kuma.io/v1alpha1
kind: TrafficPermission
mesh: default
metadata:
  name: web-to-backend
spec:
  sources:
    - match:
        kuma.io/service: web
  destinations:
    - match:
        kuma.io/service: backend
" | kubectl apply -f -
# operation should succeed, access to backend service access is granted

$ echo "
apiVersion: kuma.io/v1alpha1
kind: TrafficPermission
mesh: default
metadata:
  name: web-to-backend
spec:
  sources:
    - match:
        kuma.io/service: web
  destinations:
    - match:
        kuma.io/service: not-backend # access to this service is not granted
" | kubectl apply -f -
# operation should not succeed

Multi-zone

In a multi-zone setup, AccessRole and AccessRoleBinding are not synchronized between the global control plane and the zone control plane.