How-To: Apply access control list configuration for service invocation
Restrict what operations calling applications can perform, via service invocation, on the called application
Access control enables the configuration of policies that restrict what operations calling applications can perform, via service invocation, on the called application. To limit access to a called applications from specific operations and HTTP verbs from the calling applications, you can define an access control policy specification in configuration.
An access control policy is specified in configuration and be applied to Dapr sidecar for the called application. Example access policies are shown below and access to the called app is based on the matched policy action. You can provide a default global action for all calling applications and if no access control policy is specified, the default behavior is to allow all calling applicatons to access to the called app.
Watch this video on how to apply access control list for service invocation.
Concepts
TrustDomain - A “trust domain” is a logical group to manage trust relationships. Every application is assigned a trust domain which can be specified in the access control list policy spec. If no policy spec is defined or an empty trust domain is specified, then a default value “public” is used. This trust domain is used to generate the identity of the application in the TLS cert.
App Identity - Dapr requests the sentry service to generate a SPIFFE id for all applications and this id is attached in the TLS cert. The SPIFFE id is of the format: **spiffe://\<trustdomain>/ns/\<namespace\>/\<appid\>**
. For matching policies, the trust domain, namespace and app ID values of the calling app are extracted from the SPIFFE id in the TLS cert of the calling app. These values are matched against the trust domain, namespace and app ID values specified in the policy spec. If all three of these match, then more specific policies are further matched.
Configuration properties
The following tables lists the different properties for access control, policies and operations:
Access Control
Property | Type | Description |
---|---|---|
defaultAction | string | Global default action when no other policy is matched |
trustDomain | string | Trust domain assigned to the application. Default is “public”. |
policies | string | Policies to determine what operations the calling app can do on the called app |
Policies
Property | Type | Description |
---|---|---|
app | string | AppId of the calling app to allow/deny service invocation from |
namespace | string | Namespace value that needs to be matched with the namespace of the calling app |
trustDomain | string | Trust domain that needs to be matched with the trust domain of the calling app. Default is “public” |
defaultAction | string | App level default action in case the app is found but no specific operation is matched |
operations | string | operations that are allowed from the calling app |
Operations
Property | Type | Description |
---|---|---|
name | string | Path name of the operations allowed on the called app. Wildcard “” can be used to under a path to match |
httpVerb | list | List specific http verbs that can be used by the calling app. Wildcard “” can be used to match any http verb. Unused for grpc invocation |
action | string | Access modifier. Accepted values “allow” (default) or “deny” |
Policy rules
- If no access policy is specified, the default behavior is to allow all apps to access to all methods on the called app
- If no global default action is specified and no app specific policies defined, the empty access policy is treated like no access policy specified and the default behavior is to allow all apps to access to all methods on the called app.
- If no global default action is specified but some app specific policies have been defined, then we resort to a more secure option of assuming the global default action to deny access to all methods on the called app.
- If an access policy is defined and if the incoming app credentials cannot be verified, then the global default action takes effect.
- If either the trust domain or namespace of the incoming app do not match the values specified in the app policy, the app policy is ignored and the global default action takes effect.
Policy priority
The action corresponding to the most specific policy matched takes effect as ordered below:
- Specific HTTP verbs in the case of HTTP or the operation level action in the case of GRPC.
- The default action at the app level
- The default action at the global level
Example scenarios
Below are some example scenarios for using access control list for service invocation. See configuration guidance to understand the available configuration settings for an application sidecar.
Scenario 1: Deny access to all apps except where trustDomain = public, namespace = default, appId = app1
With this configuration, all calling methods with appId = app1 are allowed and all other invocation requests from other applications are denied
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: appconfig
spec:
accessControl:
defaultAction: deny
trustDomain: "public"
policies:
- appId: app1
defaultAction: allow
trustDomain: 'public'
namespace: "default"
Scenario 2: Deny access to all apps except trustDomain = public, namespace = default, appId = app1, operation = op1
With this configuration, only method op1 from appId = app1 is allowed and all other method requests from all other apps, including other methods on app1, are denied
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: appconfig
spec:
accessControl:
defaultAction: deny
trustDomain: "public"
policies:
- appId: app1
defaultAction: deny
trustDomain: 'public'
namespace: "default"
operations:
- name: /op1
httpVerb: ['*']
action: allow
Scenario 3: Deny access to all apps except when a specific verb for HTTP and operation for GRPC is matched
With this configuration, the only scenarios below are allowed access and and all other method requests from all other apps, including other methods on app1 or app2, are denied
- trustDomain = public, namespace = default, appID = app1, operation = op1, http verb = POST/PUT
- trustDomain = “myDomain”, namespace = “ns1”, appID = app2, operation = op2 and application protocol is GRPC , only HTTP verbs POST/PUT on method op1 from appId = app1 are allowed and all other method requests from all other apps, including other methods on app1, are denied
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: appconfig
spec:
accessControl:
defaultAction: deny
trustDomain: "public"
policies:
- appId: app1
defaultAction: deny
trustDomain: 'public'
namespace: "default"
operations:
- name: /op1
httpVerb: ['POST', 'PUT']
action: allow
- appId: app2
defaultAction: deny
trustDomain: 'myDomain'
namespace: "ns1"
operations:
- name: /op2
action: allow
Scenario 4: Allow access to all methods except trustDomain = public, namespace = default, appId = app1, operation = /op1/*, all http verbs
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: appconfig
spec:
accessControl:
defaultAction: allow
trustDomain: "public"
policies:
- appId: app1
defaultAction: allow
trustDomain: 'public'
namespace: "default"
operations:
- name: /op1/*
httpVerb: ['*']
action: deny
Scenario 5: Allow access to all methods for trustDomain = public, namespace = ns1, appId = app1 and deny access to all methods for trustDomain = public, namespace = ns2, appId = app1
This scenario shows how applications with the same app ID but belonging to different namespaces can be specified
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: appconfig
spec:
accessControl:
defaultAction: allow
trustDomain: "public"
policies:
- appId: app1
defaultAction: allow
trustDomain: 'public'
namespace: "ns1"
- appId: app1
defaultAction: deny
trustDomain: 'public'
namespace: "ns2"
Hello world examples
These examples show how to apply access control to the hello world quickstart samples where a python app invokes a node.js app. Access control lists rely on the Dapr Sentry service to generate the TLS certificates with a SPIFFE id for authentication, which means the Sentry service either has to be running locally or deployed to your hosting enviroment such as a Kubernetes cluster.
The nodeappconfig example below shows how to deny access to the neworder
method from the pythonapp
, where the python app is in the myDomain
trust domain and default
namespace. The nodeapp is in the public
trust domain.
nodeappconfig.yaml
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: nodeappconfig
spec:
tracing:
samplingRate: "1"
accessControl:
defaultAction: allow
trustDomain: "public"
policies:
- appId: pythonapp
defaultAction: allow
trustDomain: 'myDomain'
namespace: "default"
operations:
- name: /neworder
httpVerb: ['POST']
action: deny
pythonappconfig.yaml
apiVersion: dapr.io/v1alpha1
kind: Configuration
metadata:
name: pythonappconfig
spec:
tracing:
samplingRate: "1"
accessControl:
defaultAction: allow
trustDomain: "myDomain"
Self-hosted mode
This example uses the hello world quickstart.
The following steps run the Sentry service locally with mTLS enabled, set up necessary environment variables to access certificates, and then launch both the node app and python app each referencing the Sentry service to apply the ACLs.
Follow these steps to run the Sentry service in self-hosted mode with mTLS enabled
In a command prompt, set these environment variables:
```
export DAPR_TRUST_ANCHORS=`cat $HOME/.dapr/certs/ca.crt`
export DAPR_CERT_CHAIN=`cat $HOME/.dapr/certs/issuer.crt`
export DAPR_CERT_KEY=`cat $HOME/.dapr/certs/issuer.key`
export NAMESPACE=default
```
```
$env:DAPR_TRUST_ANCHORS=$(Get-Content $env:USERPROFILE\.dapr\certs\ca.crt)
$env:DAPR_CERT_CHAIN=$(Get-Content $env:USERPROFILE\.dapr\certs\issuer.crt)
$env:DAPR_CERT_KEY=$(Get-Content $env:USERPROFILE\.dapr\certs\issuer.key)
$env:NAMESPACE="default"
```
Run daprd to launch a Dapr sidecar for the node.js app with mTLS enabled, referencing the local Sentry service:
daprd --app-id nodeapp --dapr-grpc-port 50002 -dapr-http-port 3501 --log-level debug --app-port 3000 --enable-mtls --sentry-address localhost:50001 --config nodeappconfig.yaml
Run the node app in a separate command prompt:
node app.js
In another command prompt, set these environment variables:
```
export DAPR_TRUST_ANCHORS=`cat $HOME/.dapr/certs/ca.crt`
export DAPR_CERT_CHAIN=`cat $HOME/.dapr/certs/issuer.crt`
export DAPR_CERT_KEY=`cat $HOME/.dapr/certs/issuer.key`
export NAMESPACE=default
```
```
$env:DAPR_TRUST_ANCHORS=$(Get-Content $env:USERPROFILE\.dapr\certs\ca.crt)
$env:DAPR_CERT_CHAIN=$(Get-Content $env:USERPROFILE\.dapr\certs\issuer.crt)
$env:DAPR_CERT_KEY=$(Get-Content $env:USERPROFILE\.dapr\certs\issuer.key)
$env:NAMESPACE="default"
```
Run daprd to launch a Dapr sidecar for the python app with mTLS enabled, referencing the local Sentry service:
daprd --app-id pythonapp --dapr-grpc-port 50003 --metrics-port 9092 --log-level debug --enable-mtls --sentry-address localhost:50001 --config pythonappconfig.yaml
Run the python app in a separate command prompt:
python app.py
You should see the calls to the node app fail in the python app command prompt based due to the deny operation action in the nodeappconfig file. Change this action to allow and re-run the apps and you should then see this call succeed.
Kubernetes mode
This example uses the hello kubernetes quickstart.
You can create and apply the above configuration files nodeappconfig.yaml
and pythonappconfig.yaml
as described in the configuration to the Kubernetes deployments.
For example, below is how the pythonapp is deployed to Kubernetes in the default namespace with this pythonappconfig configuration file. Do the same for the nodeapp deployment and then look at the logs for the pythonapp to see the calls fail due to the deny operation action set in the nodeappconfig file. Change this action to allow and re-deploy the apps and you should then see this call succeed.
apiVersion: apps/v1
kind: Deployment
metadata:
name: pythonapp
namespace: default
labels:
app: python
spec:
replicas: 1
selector:
matchLabels:
app: python
template:
metadata:
labels:
app: python
annotations:
dapr.io/enabled: "true"
dapr.io/app-id: "pythonapp"
dapr.io/config: "pythonappconfig"
spec:
containers:
- name: python
image: dapriosamples/hello-k8s-python:edge
Last modified March 18, 2021: Merge pull request #1321 from dapr/aacrawfi/logos (9a399d5)