Merge pull request #41556 from Zhuzhenghao/cleanup/abac

cleanup page abac
pull/30817/head
Kubernetes Prow Robot 2023-06-30 06:18:42 -07:00 committed by GitHub
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---
<!-- overview -->
Attribute-based access control (ABAC) defines an access control paradigm whereby access rights are granted to users through the use of policies which combine attributes together.
Attribute-based access control (ABAC) defines an access control paradigm whereby access rights are granted
to users through the use of policies which combine attributes together.
<!-- body -->
## Policy File Format
To enable `ABAC` mode, specify `--authorization-policy-file=SOME_FILENAME` and `--authorization-mode=ABAC` on startup.
To enable `ABAC` mode, specify `--authorization-policy-file=SOME_FILENAME` and `--authorization-mode=ABAC`
on startup.
The file format is [one JSON object per line](https://jsonlines.org/). There
The file format is [one JSON object per line](https://jsonlines.org/). There
should be no enclosing list or map, only one map per line.
Each line is a "policy object", where each such object is a map with the following
properties:
- Versioning properties:
- `apiVersion`, type string; valid values are "abac.authorization.kubernetes.io/v1beta1". Allows versioning and conversion of the policy format.
- `kind`, type string: valid values are "Policy". Allows versioning and conversion of the policy format.
- `spec` property set to a map with the following properties:
- Subject-matching properties:
- `user`, type string; the user-string from `--token-auth-file`. If you specify `user`, it must match the username of the authenticated user.
- `group`, type string; if you specify `group`, it must match one of the groups of the authenticated user. `system:authenticated` matches all authenticated requests. `system:unauthenticated` matches all unauthenticated requests.
- Resource-matching properties:
- `apiGroup`, type string; an API group.
- Ex: `apps`, `networking.k8s.io`
- Wildcard: `*` matches all API groups.
- `namespace`, type string; a namespace.
- Ex: `kube-system`
- Wildcard: `*` matches all resource requests.
- `resource`, type string; a resource type
- Ex: `pods`, `deployments`
- Wildcard: `*` matches all resource requests.
- Non-resource-matching properties:
- `nonResourcePath`, type string; non-resource request paths.
- Ex: `/version` or `/apis`
- Wildcard:
- `*` matches all non-resource requests.
- `/foo/*` matches all subpaths of `/foo/`.
- `readonly`, type boolean, when true, means that the Resource-matching policy only applies to get, list, and watch operations, Non-resource-matching policy only applies to get operation.
- Versioning properties:
- `apiVersion`, type string; valid values are "abac.authorization.kubernetes.io/v1beta1". Allows versioning
and conversion of the policy format.
- `kind`, type string: valid values are "Policy". Allows versioning and conversion of the policy format.
- `spec` property set to a map with the following properties:
- Subject-matching properties:
- `user`, type string; the user-string from `--token-auth-file`. If you specify `user`, it must match the
username of the authenticated user.
- `group`, type string; if you specify `group`, it must match one of the groups of the authenticated user.
`system:authenticated` matches all authenticated requests. `system:unauthenticated` matches all
unauthenticated requests.
- Resource-matching properties:
- `apiGroup`, type string; an API group.
- Ex: `apps`, `networking.k8s.io`
- Wildcard: `*` matches all API groups.
- `namespace`, type string; a namespace.
- Ex: `kube-system`
- Wildcard: `*` matches all resource requests.
- `resource`, type string; a resource type
- Ex: `pods`, `deployments`
- Wildcard: `*` matches all resource requests.
- Non-resource-matching properties:
- `nonResourcePath`, type string; non-resource request paths.
- Ex: `/version` or `/apis`
- Wildcard:
- `*` matches all non-resource requests.
- `/foo/*` matches all subpaths of `/foo/`.
- `readonly`, type boolean, when true, means that the Resource-matching policy only applies to get, list,
and watch operations, Non-resource-matching policy only applies to get operation.
{{< note >}}
An unset property is the same as a property set to the zero value for its type
@ -61,7 +68,7 @@ REST interface.
A request has attributes which correspond to the properties of a policy object.
When a request is received, the attributes are determined. Unknown attributes
When a request is received, the attributes are determined. Unknown attributes
are set to the zero value of its type (e.g. empty string, 0, false).
A property set to `"*"` will match any value of the corresponding attribute.
@ -95,42 +102,49 @@ exposed via the `nonResourcePath` property in a policy (see [examples](#examples
To inspect the HTTP calls involved in a specific kubectl operation you can turn
up the verbosity:
kubectl --v=8 version
```shell
kubectl --v=8 version
```
## Examples
1. Alice can do anything to all resources:
1. Alice can do anything to all resources:
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "alice", "namespace": "*", "resource": "*", "apiGroup": "*"}}
```
2. The Kubelet can read any pods:
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "alice", "namespace": "*", "resource": "*", "apiGroup": "*"}}
```
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "kubelet", "namespace": "*", "resource": "pods", "readonly": true}}
```
3. The Kubelet can read and write events:
1. The kubelet can read any pods:
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "kubelet", "namespace": "*", "resource": "events"}}
```
4. Bob can just read pods in namespace "projectCaribou":
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "kubelet", "namespace": "*", "resource": "pods", "readonly": true}}
```
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "bob", "namespace": "projectCaribou", "resource": "pods", "readonly": true}}
```
5. Anyone can make read-only requests to all non-resource paths:
1. The kubelet can read and write events:
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"group": "system:authenticated", "readonly": true, "nonResourcePath": "*"}}
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "kubelet", "namespace": "*", "resource": "events"}}
```
1. Bob can just read pods in namespace "projectCaribou":
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"user": "bob", "namespace": "projectCaribou", "resource": "pods", "readonly": true}}
```
1. Anyone can make read-only requests to all non-resource paths:
```json
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"group": "system:authenticated", "readonly": true, "nonResourcePath": "*"}}
{"apiVersion": "abac.authorization.kubernetes.io/v1beta1", "kind": "Policy", "spec": {"group": "system:unauthenticated", "readonly": true, "nonResourcePath": "*"}}
```
```
[Complete file example](https://releases.k8s.io/v{{< skew currentPatchVersion >}}/pkg/auth/authorizer/abac/example_policy_file.jsonl)
## A quick note on service accounts
Every service account has a corresponding ABAC username, and that service account's username is generated according to the naming convention:
Every service account has a corresponding ABAC username, and that service account's username is generated
according to the naming convention:
```shell
system:serviceaccount:<namespace>:<serviceaccountname>
@ -142,7 +156,7 @@ Creating a new namespace leads to the creation of a new service account in the f
system:serviceaccount:<namespace>:default
```
For example, if you wanted to grant the default service account (in the `kube-system` namespace) full
For example, if you wanted to grant the default service account (in the `kube-system` namespace) full
privilege to the API using ABAC, you would add this line to your policy file:
```json
@ -150,6 +164,3 @@ privilege to the API using ABAC, you would add this line to your policy file:
```
The apiserver will need to be restarted to pick up the new policy lines.