- Improves performance of the node authorizer ([#87696](https://github.com/kubernetes/kubernetes/pull/87696), [@liggitt](https://github.com/liggitt)) [SIG Auth]

- In the course of admitting a single request, the ValidatingAdmissionPolicy plugin will perform no more than one authorization check per unique authorizer expression. All evaluations of identical authorizer expressions will produce the same decision. ([#116443](https://github.com/kubernetes/kubernetes/pull/116443), [@benluddy](https://github.com/benluddy)) [SIG API Machinery and Testing]

- Added authorization check support to the CEL expressions of ValidatingAdmissionPolicy via a `authorizer`

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    REPAIR OR CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN
    ESSENTIAL PART OF THIS LICENSE. NO USE OF ANY COVERED SOFTWARE IS
    AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.

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* Add support for the webhook authorizer to make a Deny decision that short-circuits the union authorizer and immediately returns Deny.  ([#53273](https://github.com/kubernetes/kubernetes/pull/53273), [@mikedanese](https://github.com/mikedanese))

		Description:    "The service is unavailable. Please retry.",
		HTTPStatusCode: http.StatusServiceUnavailable,
	},
	ErrUnauthorizedAccess: {
		Code:           "UnauthorizedAccess",
		Description:    "You are not authorized to perform this operation",
		HTTPStatusCode: http.StatusUnauthorized,
	},
	ErrExpressionTooLong: {
		Code:           "ExpressionTooLong",

object by patching themselves with an OwnerReference to a cluster-scoped resource. If the OwnerReference resource does not exist or is subsequently deleted, the given node object will be deleted via garbage collection. By default, node users are authorized for create and patch requests but not delete requests against their node object. Since the NodeRestriction admission controller does not prevent patching OwnerReferences, a compromised node could leverage this vulnerability to delete and then recreate...

* `list`/`watch` API requests with a `fieldSelector` that specifies `metadata.name` can now be authorized as requests for an individual named resource ([#63469](https://github.com/kubernetes/kubernetes/pull/63469), [@wojtek-t](https://github.com/wojtek-t))

adds an alpha AuthorizeNodeWithSelectors feature that makes the node authorizer limit requests from node API clients to get / list / watch its own Node API object, and to get / list / watch its own Pod API objects. Clients using kubelet credentials to read other nodes or unrelated pods must change their authentication credentials (recommended), adjust their usage, or grant broader read access independent of the node authorizer. ([#125571](https://github.com/kubernetes/kubernetes/pull/125571), [@...

    server.enqueue(MockResponse(body = "this response comes via HTTPS"))
    server.enqueue(MockResponse(body = "another response via HTTPS"))

    // install a custom SSL socket factory so the server can be authorized
    client =
      client
        .newBuilder()
        .sslSocketFactory(
          handshakeCertificates.sslSocketFactory(),
          handshakeCertificates.trustManager,