rebase: bump k8s.io/kubernetes from 1.26.2 to 1.27.2

Bumps [k8s.io/kubernetes](https://github.com/kubernetes/kubernetes) from 1.26.2 to 1.27.2.
- [Release notes](https://github.com/kubernetes/kubernetes/releases)
- [Commits](https://github.com/kubernetes/kubernetes/compare/v1.26.2...v1.27.2)

---
updated-dependencies:
- dependency-name: k8s.io/kubernetes
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/k8s.io/apiserver/pkg/server/dynamiccertificates/tlsconfig.go

@@ -0,0 +1,284 @@
+/*
+Copyright 2019 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package dynamiccertificates
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"net"
+	"sync/atomic"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/tools/events"
+	"k8s.io/client-go/util/cert"
+	"k8s.io/client-go/util/workqueue"
+	"k8s.io/klog/v2"
+)
+
+const workItemKey = "key"
+
+// DynamicServingCertificateController dynamically loads certificates and provides a golang tls compatible dynamic GetCertificate func.
+type DynamicServingCertificateController struct {
+	// baseTLSConfig is the static portion of the tlsConfig for serving to clients.  It is copied and the copy is mutated
+	// based on the dynamic cert state.
+	baseTLSConfig *tls.Config
+
+	// clientCA provides the very latest content of the ca bundle
+	clientCA CAContentProvider
+	// servingCert provides the very latest content of the default serving certificate
+	servingCert CertKeyContentProvider
+	// sniCerts are a list of CertKeyContentProvider with associated names used for SNI
+	sniCerts []SNICertKeyContentProvider
+
+	// currentlyServedContent holds the original bytes that we are serving. This is used to decide if we need to set a
+	// new atomic value. The types used for efficient TLSConfig preclude using the processed value.
+	currentlyServedContent *dynamicCertificateContent
+	// currentServingTLSConfig holds a *tls.Config that will be used to serve requests
+	currentServingTLSConfig atomic.Value
+
+	// queue only ever has one item, but it has nice error handling backoff/retry semantics
+	queue         workqueue.RateLimitingInterface
+	eventRecorder events.EventRecorder
+}
+
+var _ Listener = &DynamicServingCertificateController{}
+
+// NewDynamicServingCertificateController returns a controller that can be used to keep a TLSConfig up to date.
+func NewDynamicServingCertificateController(
+	baseTLSConfig *tls.Config,
+	clientCA CAContentProvider,
+	servingCert CertKeyContentProvider,
+	sniCerts []SNICertKeyContentProvider,
+	eventRecorder events.EventRecorder,
+) *DynamicServingCertificateController {
+	c := &DynamicServingCertificateController{
+		baseTLSConfig: baseTLSConfig,
+		clientCA:      clientCA,
+		servingCert:   servingCert,
+		sniCerts:      sniCerts,
+
+		queue:         workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "DynamicServingCertificateController"),
+		eventRecorder: eventRecorder,
+	}
+
+	return c
+}
+
+// GetConfigForClient is an implementation of tls.Config.GetConfigForClient
+func (c *DynamicServingCertificateController) GetConfigForClient(clientHello *tls.ClientHelloInfo) (*tls.Config, error) {
+	uncastObj := c.currentServingTLSConfig.Load()
+	if uncastObj == nil {
+		return nil, errors.New("dynamiccertificates: configuration not ready")
+	}
+	tlsConfig, ok := uncastObj.(*tls.Config)
+	if !ok {
+		return nil, errors.New("dynamiccertificates: unexpected config type")
+	}
+
+	tlsConfigCopy := tlsConfig.Clone()
+
+	// if the client set SNI information, just use our "normal" SNI flow
+	if len(clientHello.ServerName) > 0 {
+		return tlsConfigCopy, nil
+	}
+
+	// if the client didn't set SNI, then we need to inspect the requested IP so that we can choose
+	// a certificate from our list if we specifically handle that IP.  This can happen when an IP is specifically mapped by name.
+	host, _, err := net.SplitHostPort(clientHello.Conn.LocalAddr().String())
+	if err != nil {
+		return tlsConfigCopy, nil
+	}
+
+	ipCert, ok := tlsConfigCopy.NameToCertificate[host]
+	if !ok {
+		return tlsConfigCopy, nil
+	}
+	tlsConfigCopy.Certificates = []tls.Certificate{*ipCert}
+	tlsConfigCopy.NameToCertificate = nil
+
+	return tlsConfigCopy, nil
+}
+
+// newTLSContent determines the next set of content for overriding the baseTLSConfig.
+func (c *DynamicServingCertificateController) newTLSContent() (*dynamicCertificateContent, error) {
+	newContent := &dynamicCertificateContent{}
+
+	if c.clientCA != nil {
+		currClientCABundle := c.clientCA.CurrentCABundleContent()
+		// we allow removing all client ca bundles because the server is still secure when this happens. it just means
+		// that there isn't a hint to clients about which client-cert to used.  this happens when there is no client-ca
+		// yet known for authentication, which can happen in aggregated apiservers and some kube-apiserver deployment modes.
+		newContent.clientCA = caBundleContent{caBundle: currClientCABundle}
+	}
+
+	if c.servingCert != nil {
+		currServingCert, currServingKey := c.servingCert.CurrentCertKeyContent()
+		if len(currServingCert) == 0 || len(currServingKey) == 0 {
+			return nil, fmt.Errorf("not loading an empty serving certificate from %q", c.servingCert.Name())
+		}
+
+		newContent.servingCert = certKeyContent{cert: currServingCert, key: currServingKey}
+	}
+
+	for i, sniCert := range c.sniCerts {
+		currCert, currKey := sniCert.CurrentCertKeyContent()
+		if len(currCert) == 0 || len(currKey) == 0 {
+			return nil, fmt.Errorf("not loading an empty SNI certificate from %d/%q", i, sniCert.Name())
+		}
+
+		newContent.sniCerts = append(newContent.sniCerts, sniCertKeyContent{certKeyContent: certKeyContent{cert: currCert, key: currKey}, sniNames: sniCert.SNINames()})
+	}
+
+	return newContent, nil
+}
+
+// syncCerts gets newTLSContent, if it has changed from the existing, the content is parsed and stored for usage in
+// GetConfigForClient.
+func (c *DynamicServingCertificateController) syncCerts() error {
+	newContent, err := c.newTLSContent()
+	if err != nil {
+		return err
+	}
+	// if the content is the same as what we currently have, we can simply skip it.  This works because we are single
+	// threaded.  If you ever make this multi-threaded, add a lock.
+	if newContent.Equal(c.currentlyServedContent) {
+		return nil
+	}
+
+	// make a shallow copy and override the dynamic pieces which have changed.
+	newTLSConfigCopy := c.baseTLSConfig.Clone()
+
+	// parse new content to add to TLSConfig
+	if len(newContent.clientCA.caBundle) > 0 {
+		newClientCAPool := x509.NewCertPool()
+		newClientCAs, err := cert.ParseCertsPEM(newContent.clientCA.caBundle)
+		if err != nil {
+			return fmt.Errorf("unable to load client CA file %q: %v", string(newContent.clientCA.caBundle), err)
+		}
+		for i, cert := range newClientCAs {
+			klog.V(2).InfoS("Loaded client CA", "index", i, "certName", c.clientCA.Name(), "certDetail", GetHumanCertDetail(cert))
+			if c.eventRecorder != nil {
+				c.eventRecorder.Eventf(&corev1.ObjectReference{Name: c.clientCA.Name()}, nil, corev1.EventTypeWarning, "TLSConfigChanged", "CACertificateReload", "loaded client CA [%d/%q]: %s", i, c.clientCA.Name(), GetHumanCertDetail(cert))
+			}
+
+			newClientCAPool.AddCert(cert)
+		}
+
+		newTLSConfigCopy.ClientCAs = newClientCAPool
+	}
+
+	if len(newContent.servingCert.cert) > 0 && len(newContent.servingCert.key) > 0 {
+		cert, err := tls.X509KeyPair(newContent.servingCert.cert, newContent.servingCert.key)
+		if err != nil {
+			return fmt.Errorf("invalid serving cert keypair: %v", err)
+		}
+
+		x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
+		if err != nil {
+			return fmt.Errorf("invalid serving cert: %v", err)
+		}
+
+		klog.V(2).InfoS("Loaded serving cert", "certName", c.servingCert.Name(), "certDetail", GetHumanCertDetail(x509Cert))
+		if c.eventRecorder != nil {
+			c.eventRecorder.Eventf(&corev1.ObjectReference{Name: c.servingCert.Name()}, nil, corev1.EventTypeWarning, "TLSConfigChanged", "ServingCertificateReload", "loaded serving cert [%q]: %s", c.servingCert.Name(), GetHumanCertDetail(x509Cert))
+		}
+
+		newTLSConfigCopy.Certificates = []tls.Certificate{cert}
+	}
+
+	if len(newContent.sniCerts) > 0 {
+		newTLSConfigCopy.NameToCertificate, err = c.BuildNamedCertificates(newContent.sniCerts)
+		if err != nil {
+			return fmt.Errorf("unable to build named certificate map: %v", err)
+		}
+
+		// append all named certs. Otherwise, the go tls stack will think no SNI processing
+		// is necessary because there is only one cert anyway.
+		// Moreover, if servingCert is not set, the first SNI
+		// cert will become the default cert. That's what we expect anyway.
+		for _, sniCert := range newTLSConfigCopy.NameToCertificate {
+			newTLSConfigCopy.Certificates = append(newTLSConfigCopy.Certificates, *sniCert)
+		}
+	}
+
+	// store new values of content for serving.
+	c.currentServingTLSConfig.Store(newTLSConfigCopy)
+	c.currentlyServedContent = newContent // this is single threaded, so we have no locking issue
+
+	return nil
+}
+
+// RunOnce runs a single sync step to ensure that we have a valid starting configuration.
+func (c *DynamicServingCertificateController) RunOnce() error {
+	return c.syncCerts()
+}
+
+// Run starts the kube-apiserver and blocks until stopCh is closed.
+func (c *DynamicServingCertificateController) Run(workers int, stopCh <-chan struct{}) {
+	defer utilruntime.HandleCrash()
+	defer c.queue.ShutDown()
+
+	klog.InfoS("Starting DynamicServingCertificateController")
+	defer klog.InfoS("Shutting down DynamicServingCertificateController")
+
+	// synchronously load once.  We will trigger again, so ignoring any error is fine
+	_ = c.RunOnce()
+
+	// doesn't matter what workers say, only start one.
+	go wait.Until(c.runWorker, time.Second, stopCh)
+
+	// start timer that rechecks every minute, just in case.  this also serves to prime the controller quickly.
+	go wait.Until(func() {
+		c.Enqueue()
+	}, 1*time.Minute, stopCh)
+
+	<-stopCh
+}
+
+func (c *DynamicServingCertificateController) runWorker() {
+	for c.processNextWorkItem() {
+	}
+}
+
+func (c *DynamicServingCertificateController) processNextWorkItem() bool {
+	dsKey, quit := c.queue.Get()
+	if quit {
+		return false
+	}
+	defer c.queue.Done(dsKey)
+
+	err := c.syncCerts()
+	if err == nil {
+		c.queue.Forget(dsKey)
+		return true
+	}
+
+	utilruntime.HandleError(fmt.Errorf("%v failed with : %v", dsKey, err))
+	c.queue.AddRateLimited(dsKey)
+
+	return true
+}
+
+// Enqueue a method to allow separate control loops to cause the certificate controller to trigger and read content.
+func (c *DynamicServingCertificateController) Enqueue() {
+	c.queue.Add(workItemKey)
+}