245 lines
7.3 KiB
Go
245 lines
7.3 KiB
Go
/*
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Copyright 2016 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package server
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import (
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"crypto/tls"
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"crypto/x509"
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"fmt"
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"net"
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"net/http"
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"strings"
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"sync"
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"time"
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utilruntime "k8s.io/apimachinery/pkg/util/runtime"
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"k8s.io/apimachinery/pkg/util/validation"
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"github.com/golang/glog"
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"github.com/pkg/errors"
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)
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const (
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defaultKeepAlivePeriod = 3 * time.Minute
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)
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// serveSecurely runs the secure http server. It fails only if certificates cannot
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// be loaded or the initial listen call fails. The actual server loop (stoppable by closing
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// stopCh) runs in a go routine, i.e. serveSecurely does not block.
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func (s *GenericAPIServer) serveSecurely(stopCh <-chan struct{}) error {
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secureServer := &http.Server{
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Addr: s.SecureServingInfo.BindAddress,
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Handler: s.Handler,
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MaxHeaderBytes: 1 << 20,
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TLSConfig: &tls.Config{
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NameToCertificate: s.SecureServingInfo.SNICerts,
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// Can't use SSLv3 because of POODLE and BEAST
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// Can't use TLSv1.0 because of POODLE and BEAST using CBC cipher
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// Can't use TLSv1.1 because of RC4 cipher usage
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MinVersion: tls.VersionTLS12,
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// enable HTTP2 for go's 1.7 HTTP Server
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NextProtos: []string{"h2", "http/1.1"},
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},
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}
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if s.SecureServingInfo.Cert != nil {
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secureServer.TLSConfig.Certificates = []tls.Certificate{*s.SecureServingInfo.Cert}
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}
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// append all named certs. Otherwise, the go tls stack will think no SNI processing
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// is necessary because there is only one cert anyway.
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// Moreover, if ServerCert.CertFile/ServerCert.KeyFile are not set, the first SNI
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// cert will become the default cert. That's what we expect anyway.
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for _, c := range s.SecureServingInfo.SNICerts {
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secureServer.TLSConfig.Certificates = append(secureServer.TLSConfig.Certificates, *c)
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}
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if s.SecureServingInfo.ClientCA != nil {
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// Populate PeerCertificates in requests, but don't reject connections without certificates
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// This allows certificates to be validated by authenticators, while still allowing other auth types
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secureServer.TLSConfig.ClientAuth = tls.RequestClientCert
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// Specify allowed CAs for client certificates
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secureServer.TLSConfig.ClientCAs = s.SecureServingInfo.ClientCA
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}
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glog.Infof("Serving securely on %s", s.SecureServingInfo.BindAddress)
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var err error
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s.effectiveSecurePort, err = runServer(secureServer, s.SecureServingInfo.BindNetwork, stopCh)
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return err
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}
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// serveInsecurely run the insecure http server. It fails only if the initial listen
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// call fails. The actual server loop (stoppable by closing stopCh) runs in a go
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// routine, i.e. serveInsecurely does not block.
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func (s *GenericAPIServer) serveInsecurely(stopCh <-chan struct{}) error {
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insecureServer := &http.Server{
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Addr: s.InsecureServingInfo.BindAddress,
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Handler: s.InsecureHandler,
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MaxHeaderBytes: 1 << 20,
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}
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glog.Infof("Serving insecurely on %s", s.InsecureServingInfo.BindAddress)
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var err error
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s.effectiveInsecurePort, err = runServer(insecureServer, s.InsecureServingInfo.BindNetwork, stopCh)
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return err
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}
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// runServer listens on the given port, then spawns a go-routine continuously serving
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// until the stopCh is closed. The port is returned. This function does not block.
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func runServer(server *http.Server, network string, stopCh <-chan struct{}) (int, error) {
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if len(server.Addr) == 0 {
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return 0, errors.New("address cannot be empty")
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}
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if len(network) == 0 {
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network = "tcp"
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}
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// first listen is synchronous (fail early!)
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ln, err := net.Listen(network, server.Addr)
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if err != nil {
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return 0, fmt.Errorf("failed to listen on %v: %v", server.Addr, err)
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}
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// get port
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tcpAddr, ok := ln.Addr().(*net.TCPAddr)
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if !ok {
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ln.Close()
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return 0, fmt.Errorf("invalid listen address: %q", ln.Addr().String())
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}
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lock := sync.Mutex{} // to avoid we close an old listener during a listen retry
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go func() {
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<-stopCh
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lock.Lock()
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defer lock.Unlock()
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ln.Close()
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}()
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go func() {
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defer utilruntime.HandleCrash()
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for {
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var listener net.Listener
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listener = tcpKeepAliveListener{ln.(*net.TCPListener)}
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if server.TLSConfig != nil {
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listener = tls.NewListener(listener, server.TLSConfig)
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}
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err := server.Serve(listener)
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glog.Errorf("Error serving %v (%v); will try again.", server.Addr, err)
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// listen again
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func() {
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lock.Lock()
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defer lock.Unlock()
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for {
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time.Sleep(15 * time.Second)
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ln, err = net.Listen("tcp", server.Addr)
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if err == nil {
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return
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}
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select {
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case <-stopCh:
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return
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default:
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}
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glog.Errorf("Error listening on %v (%v); will try again.", server.Addr, err)
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}
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}()
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select {
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case <-stopCh:
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return
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default:
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}
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}
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}()
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return tcpAddr.Port, nil
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}
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type namedTlsCert struct {
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tlsCert tls.Certificate
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// names is a list of domain patterns: fully qualified domain names, possibly prefixed with
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// wildcard segments.
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names []string
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}
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// getNamedCertificateMap returns a map of *tls.Certificate by name. It's is
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// suitable for use in tls.Config#NamedCertificates. Returns an error if any of the certs
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// cannot be loaded. Returns nil if len(certs) == 0
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func getNamedCertificateMap(certs []namedTlsCert) (map[string]*tls.Certificate, error) {
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// register certs with implicit names first, reverse order such that earlier trump over the later
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byName := map[string]*tls.Certificate{}
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for i := len(certs) - 1; i >= 0; i-- {
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if len(certs[i].names) > 0 {
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continue
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}
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cert := &certs[i].tlsCert
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// read names from certificate common names and DNS names
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if len(cert.Certificate) == 0 {
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return nil, fmt.Errorf("empty SNI certificate, skipping")
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}
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x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
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if err != nil {
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return nil, fmt.Errorf("parse error for SNI certificate: %v", err)
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}
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cn := x509Cert.Subject.CommonName
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if cn == "*" || len(validation.IsDNS1123Subdomain(strings.TrimPrefix(cn, "*."))) == 0 {
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byName[cn] = cert
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}
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for _, san := range x509Cert.DNSNames {
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byName[san] = cert
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}
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// intentionally all IPs in the cert are ignored as SNI forbids passing IPs
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// to select a cert. Before go 1.6 the tls happily passed IPs as SNI values.
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}
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// register certs with explicit names last, overwriting every of the implicit ones,
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// again in reverse order.
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for i := len(certs) - 1; i >= 0; i-- {
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namedCert := &certs[i]
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for _, name := range namedCert.names {
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byName[name] = &certs[i].tlsCert
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}
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}
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return byName, nil
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}
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// tcpKeepAliveListener sets TCP keep-alive timeouts on accepted
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// connections. It's used by ListenAndServe and ListenAndServeTLS so
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// dead TCP connections (e.g. closing laptop mid-download) eventually
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// go away.
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//
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// Copied from Go 1.7.2 net/http/server.go
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type tcpKeepAliveListener struct {
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*net.TCPListener
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}
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func (ln tcpKeepAliveListener) Accept() (net.Conn, error) {
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tc, err := ln.AcceptTCP()
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if err != nil {
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return nil, err
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}
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tc.SetKeepAlive(true)
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tc.SetKeepAlivePeriod(defaultKeepAlivePeriod)
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return tc, nil
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}
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