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Network component should refresh certificates if they expire
A single process openshift start node has both kubelet and network. Kubelet rotates its client certs - network does not. Until we split out network we need to do something minimal to ensure the cert is refreshed. Use the same code as the kubelet, but when the cert expires check disk and see if it was refreshed. That should work for bootstrapped environments because the file is updated.
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224
pkg/cmd/server/kubernetes/network/transport/transport.go
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,224 @@ | ||
| /* | ||
| Copyright 2017 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. | ||
| */ | ||
|
|
||
| // Extracted from k8s.io/kubernetes/pkg/kubelet/certificate/transport.go, will be removed | ||
| // when openshift-sdn and the network components move out of the Kubelet. Is intended ONLY | ||
| // to provide certificate rollover until 3.8/3.9. | ||
| package transport | ||
|
|
||
| import ( | ||
| "context" | ||
| "crypto/tls" | ||
| "fmt" | ||
| "net" | ||
| "net/http" | ||
| "sync" | ||
| "time" | ||
|
|
||
| "github.com/golang/glog" | ||
|
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| utilnet "k8s.io/apimachinery/pkg/util/net" | ||
| utilruntime "k8s.io/apimachinery/pkg/util/runtime" | ||
| "k8s.io/apimachinery/pkg/util/wait" | ||
| restclient "k8s.io/client-go/rest" | ||
| "k8s.io/kubernetes/pkg/kubelet/certificate" | ||
| ) | ||
|
|
||
| // RefreshCertificateAfterExpiry instruments a restconfig with a transport that checks | ||
| // disk to reload expired certificates. | ||
| // | ||
| // The config must not already provide an explicit transport. | ||
| // | ||
| // The returned transport periodically checks the manager to determine if the | ||
| // certificate has changed. If it has, the transport shuts down all existing client | ||
| // connections, forcing the client to re-handshake with the server and use the | ||
| // new certificate. | ||
| // | ||
| // stopCh should be used to indicate when the transport is unused and doesn't need | ||
| // to continue checking the manager. | ||
| func RefreshCertificateAfterExpiry(stopCh <-chan struct{}, period time.Duration, clientConfig *restclient.Config, store certificate.Store) error { | ||
| if clientConfig.Transport != nil { | ||
| return fmt.Errorf("there is already a transport configured") | ||
| } | ||
| tlsConfig, err := restclient.TLSConfigFor(clientConfig) | ||
| if err != nil { | ||
| return fmt.Errorf("unable to configure TLS for the rest client: %v", err) | ||
| } | ||
| if tlsConfig == nil { | ||
| tlsConfig = &tls.Config{} | ||
| } | ||
| manager := &certificateManager{ | ||
| store: store, | ||
| minimumRefresh: period, | ||
| // begin attempting to refresh the certificate before it expires, assuming that rotation occurs before | ||
| // expiration | ||
| expireWindow: 3 * time.Minute, | ||
| } | ||
| tlsConfig.Certificates = nil | ||
| tlsConfig.GetClientCertificate = func(requestInfo *tls.CertificateRequestInfo) (*tls.Certificate, error) { | ||
| cert := manager.Current() | ||
| if cert == nil { | ||
| return &tls.Certificate{Certificate: nil}, nil | ||
| } | ||
| return cert, nil | ||
| } | ||
|
|
||
| // Custom dialer that will track all connections it creates. | ||
| t := &connTracker{ | ||
| dialer: &net.Dialer{Timeout: 30 * time.Second, KeepAlive: 30 * time.Second}, | ||
| conns: make(map[*closableConn]struct{}), | ||
| } | ||
|
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| // Watch for certs to change, and then close connections after at least one period has elapsed. | ||
| lastCert := manager.Current() | ||
| detectedCertChange := false | ||
| go wait.Until(func() { | ||
| if detectedCertChange { | ||
| // To avoid races with new connections getting old certificates after the close happens, wait | ||
| // at least period before closing connections. | ||
| detectedCertChange = false | ||
| glog.Infof("certificate rotation detected, shutting down client connections to start using new credentials") | ||
| // The cert has been rotated. Close all existing connections to force the client | ||
| // to reperform its TLS handshake with new cert. | ||
| // | ||
| // See: https://github.com/kubernetes-incubator/bootkube/pull/663#issuecomment-318506493 | ||
| t.closeAllConns() | ||
| } | ||
| curr := manager.Current() | ||
| if curr == nil || lastCert == curr { | ||
| // Cert hasn't been rotated. | ||
| return | ||
| } | ||
| lastCert = curr | ||
| detectedCertChange = true | ||
| }, period, stopCh) | ||
|
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| clientConfig.Transport = utilnet.SetTransportDefaults(&http.Transport{ | ||
| TLSClientConfig: tlsConfig, | ||
| MaxIdleConnsPerHost: 25, | ||
| DialContext: t.DialContext, // Use custom dialer. | ||
| }) | ||
|
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| // Zero out all existing TLS options since our new transport enforces them. | ||
| clientConfig.CertData = nil | ||
| clientConfig.KeyData = nil | ||
| clientConfig.CertFile = "" | ||
| clientConfig.KeyFile = "" | ||
| clientConfig.CAData = nil | ||
| clientConfig.CAFile = "" | ||
| clientConfig.Insecure = false | ||
| return nil | ||
| } | ||
|
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| // certificateManager reloads the requested certificate from disk when requested. | ||
| type certificateManager struct { | ||
| store certificate.Store | ||
| minimumRefresh time.Duration | ||
| expireWindow time.Duration | ||
|
|
||
| lock sync.Mutex | ||
| cert *tls.Certificate | ||
| lastCheck time.Time | ||
| } | ||
|
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| // Current retrieves the latest certificate from disk if it exists, or nil if | ||
| // no certificate could be found. The last successfully loaded certificate will be | ||
| // returned. | ||
| func (m *certificateManager) Current() *tls.Certificate { | ||
| m.lock.Lock() | ||
| defer m.lock.Unlock() | ||
|
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| // check whether the cert has expired and whether we've waited long enough since our last | ||
| // check to look again | ||
| cert := m.cert | ||
| if cert != nil { | ||
| now := time.Now() | ||
| if now.After(cert.Leaf.NotAfter.Add(-m.expireWindow)) { | ||
| if now.Sub(m.lastCheck) > m.minimumRefresh { | ||
| glog.V(2).Infof("Current client certificate is about to expire, checking from disk") | ||
| cert = nil | ||
| m.lastCheck = now | ||
| } | ||
| } | ||
| } | ||
|
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||
| // load the cert from disk and parse the leaf cert | ||
| if cert == nil { | ||
| glog.V(2).Infof("Refreshing client certificate from store") | ||
| c, err := m.store.Current() | ||
| if err != nil { | ||
| utilruntime.HandleError(fmt.Errorf("Unable to load client certificate key pair from disk: %v", err)) | ||
| return nil | ||
| } | ||
| m.cert = c | ||
| } | ||
| return m.cert | ||
| } | ||
|
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| // connTracker is a dialer that tracks all open connections it creates. | ||
| type connTracker struct { | ||
| dialer *net.Dialer | ||
|
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| mu sync.Mutex | ||
| conns map[*closableConn]struct{} | ||
| } | ||
|
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| // closeAllConns forcibly closes all tracked connections. | ||
| func (c *connTracker) closeAllConns() { | ||
| c.mu.Lock() | ||
| conns := c.conns | ||
| c.conns = make(map[*closableConn]struct{}) | ||
| c.mu.Unlock() | ||
|
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||
| for conn := range conns { | ||
| conn.Close() | ||
| } | ||
| } | ||
|
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| func (c *connTracker) DialContext(ctx context.Context, network, address string) (net.Conn, error) { | ||
| conn, err := c.dialer.DialContext(ctx, network, address) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| closable := &closableConn{Conn: conn} | ||
|
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| // Start tracking the connection | ||
| c.mu.Lock() | ||
| c.conns[closable] = struct{}{} | ||
| c.mu.Unlock() | ||
|
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| // When the connection is closed, remove it from the map. This will | ||
| // be no-op if the connection isn't in the map, e.g. if closeAllConns() | ||
| // is called. | ||
| closable.onClose = func() { | ||
| c.mu.Lock() | ||
| delete(c.conns, closable) | ||
| c.mu.Unlock() | ||
| } | ||
|
|
||
| return closable, nil | ||
| } | ||
|
|
||
| type closableConn struct { | ||
| onClose func() | ||
| net.Conn | ||
| } | ||
|
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| func (c *closableConn) Close() error { | ||
| go c.onClose() | ||
| return c.Conn.Close() | ||
| } |