| // Copyright 2015 The etcd 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 transport |
| |
| import ( |
| "crypto/ecdsa" |
| "crypto/elliptic" |
| "crypto/rand" |
| "crypto/tls" |
| "crypto/x509" |
| "crypto/x509/pkix" |
| "encoding/pem" |
| "errors" |
| "fmt" |
| "math/big" |
| "net" |
| "os" |
| "path/filepath" |
| "strings" |
| "time" |
| |
| "go.etcd.io/etcd/pkg/tlsutil" |
| |
| "go.uber.org/zap" |
| ) |
| |
| // NewListener creates a new listner. |
| func NewListener(addr, scheme string, tlsinfo *TLSInfo) (l net.Listener, err error) { |
| if l, err = newListener(addr, scheme); err != nil { |
| return nil, err |
| } |
| return wrapTLS(scheme, tlsinfo, l) |
| } |
| |
| func newListener(addr string, scheme string) (net.Listener, error) { |
| if scheme == "unix" || scheme == "unixs" { |
| // unix sockets via unix://laddr |
| return NewUnixListener(addr) |
| } |
| return net.Listen("tcp", addr) |
| } |
| |
| func wrapTLS(scheme string, tlsinfo *TLSInfo, l net.Listener) (net.Listener, error) { |
| if scheme != "https" && scheme != "unixs" { |
| return l, nil |
| } |
| if tlsinfo != nil && tlsinfo.SkipClientSANVerify { |
| return NewTLSListener(l, tlsinfo) |
| } |
| return newTLSListener(l, tlsinfo, checkSAN) |
| } |
| |
| type TLSInfo struct { |
| CertFile string |
| KeyFile string |
| TrustedCAFile string |
| ClientCertAuth bool |
| CRLFile string |
| InsecureSkipVerify bool |
| SkipClientSANVerify bool |
| |
| // ServerName ensures the cert matches the given host in case of discovery / virtual hosting |
| ServerName string |
| |
| // HandshakeFailure is optionally called when a connection fails to handshake. The |
| // connection will be closed immediately afterwards. |
| HandshakeFailure func(*tls.Conn, error) |
| |
| // CipherSuites is a list of supported cipher suites. |
| // If empty, Go auto-populates it by default. |
| // Note that cipher suites are prioritized in the given order. |
| CipherSuites []uint16 |
| |
| selfCert bool |
| |
| // parseFunc exists to simplify testing. Typically, parseFunc |
| // should be left nil. In that case, tls.X509KeyPair will be used. |
| parseFunc func([]byte, []byte) (tls.Certificate, error) |
| |
| // AllowedCN is a CN which must be provided by a client. |
| AllowedCN string |
| |
| // AllowedHostname is an IP address or hostname that must match the TLS |
| // certificate provided by a client. |
| AllowedHostname string |
| |
| // Logger logs TLS errors. |
| // If nil, all logs are discarded. |
| Logger *zap.Logger |
| |
| // EmptyCN indicates that the cert must have empty CN. |
| // If true, ClientConfig() will return an error for a cert with non empty CN. |
| EmptyCN bool |
| } |
| |
| func (info TLSInfo) String() string { |
| return fmt.Sprintf("cert = %s, key = %s, trusted-ca = %s, client-cert-auth = %v, crl-file = %s", info.CertFile, info.KeyFile, info.TrustedCAFile, info.ClientCertAuth, info.CRLFile) |
| } |
| |
| func (info TLSInfo) Empty() bool { |
| return info.CertFile == "" && info.KeyFile == "" |
| } |
| |
| func SelfCert(lg *zap.Logger, dirpath string, hosts []string, additionalUsages ...x509.ExtKeyUsage) (info TLSInfo, err error) { |
| if err = os.MkdirAll(dirpath, 0700); err != nil { |
| return |
| } |
| info.Logger = lg |
| |
| certPath := filepath.Join(dirpath, "cert.pem") |
| keyPath := filepath.Join(dirpath, "key.pem") |
| _, errcert := os.Stat(certPath) |
| _, errkey := os.Stat(keyPath) |
| if errcert == nil && errkey == nil { |
| info.CertFile = certPath |
| info.KeyFile = keyPath |
| info.selfCert = true |
| return |
| } |
| |
| serialNumberLimit := new(big.Int).Lsh(big.NewInt(1), 128) |
| serialNumber, err := rand.Int(rand.Reader, serialNumberLimit) |
| if err != nil { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "cannot generate random number", |
| zap.Error(err), |
| ) |
| } |
| return |
| } |
| |
| tmpl := x509.Certificate{ |
| SerialNumber: serialNumber, |
| Subject: pkix.Name{Organization: []string{"etcd"}}, |
| NotBefore: time.Now(), |
| NotAfter: time.Now().Add(365 * (24 * time.Hour)), |
| |
| KeyUsage: x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature, |
| ExtKeyUsage: append([]x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth}, additionalUsages...), |
| BasicConstraintsValid: true, |
| } |
| |
| for _, host := range hosts { |
| h, _, _ := net.SplitHostPort(host) |
| if ip := net.ParseIP(h); ip != nil { |
| tmpl.IPAddresses = append(tmpl.IPAddresses, ip) |
| } else { |
| tmpl.DNSNames = append(tmpl.DNSNames, h) |
| } |
| } |
| |
| priv, err := ecdsa.GenerateKey(elliptic.P521(), rand.Reader) |
| if err != nil { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "cannot generate ECDSA key", |
| zap.Error(err), |
| ) |
| } |
| return |
| } |
| |
| derBytes, err := x509.CreateCertificate(rand.Reader, &tmpl, &tmpl, &priv.PublicKey, priv) |
| if err != nil { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "cannot generate x509 certificate", |
| zap.Error(err), |
| ) |
| } |
| return |
| } |
| |
| certOut, err := os.Create(certPath) |
| if err != nil { |
| info.Logger.Warn( |
| "cannot cert file", |
| zap.String("path", certPath), |
| zap.Error(err), |
| ) |
| return |
| } |
| pem.Encode(certOut, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes}) |
| certOut.Close() |
| if info.Logger != nil { |
| info.Logger.Info("created cert file", zap.String("path", certPath)) |
| } |
| |
| b, err := x509.MarshalECPrivateKey(priv) |
| if err != nil { |
| return |
| } |
| keyOut, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600) |
| if err != nil { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "cannot key file", |
| zap.String("path", keyPath), |
| zap.Error(err), |
| ) |
| } |
| return |
| } |
| pem.Encode(keyOut, &pem.Block{Type: "EC PRIVATE KEY", Bytes: b}) |
| keyOut.Close() |
| if info.Logger != nil { |
| info.Logger.Info("created key file", zap.String("path", keyPath)) |
| } |
| return SelfCert(lg, dirpath, hosts) |
| } |
| |
| // baseConfig is called on initial TLS handshake start. |
| // |
| // Previously, |
| // 1. Server has non-empty (*tls.Config).Certificates on client hello |
| // 2. Server calls (*tls.Config).GetCertificate iff: |
| // - Server's (*tls.Config).Certificates is not empty, or |
| // - Client supplies SNI; non-empty (*tls.ClientHelloInfo).ServerName |
| // |
| // When (*tls.Config).Certificates is always populated on initial handshake, |
| // client is expected to provide a valid matching SNI to pass the TLS |
| // verification, thus trigger server (*tls.Config).GetCertificate to reload |
| // TLS assets. However, a cert whose SAN field does not include domain names |
| // but only IP addresses, has empty (*tls.ClientHelloInfo).ServerName, thus |
| // it was never able to trigger TLS reload on initial handshake; first |
| // ceritifcate object was being used, never being updated. |
| // |
| // Now, (*tls.Config).Certificates is created empty on initial TLS client |
| // handshake, in order to trigger (*tls.Config).GetCertificate and populate |
| // rest of the certificates on every new TLS connection, even when client |
| // SNI is empty (e.g. cert only includes IPs). |
| func (info TLSInfo) baseConfig() (*tls.Config, error) { |
| if info.KeyFile == "" || info.CertFile == "" { |
| return nil, fmt.Errorf("KeyFile and CertFile must both be present[key: %v, cert: %v]", info.KeyFile, info.CertFile) |
| } |
| if info.Logger == nil { |
| info.Logger = zap.NewNop() |
| } |
| |
| _, err := tlsutil.NewCert(info.CertFile, info.KeyFile, info.parseFunc) |
| if err != nil { |
| return nil, err |
| } |
| |
| cfg := &tls.Config{ |
| MinVersion: tls.VersionTLS12, |
| ServerName: info.ServerName, |
| } |
| |
| if len(info.CipherSuites) > 0 { |
| cfg.CipherSuites = info.CipherSuites |
| } |
| |
| // Client certificates may be verified by either an exact match on the CN, |
| // or a more general check of the CN and SANs. |
| var verifyCertificate func(*x509.Certificate) bool |
| if info.AllowedCN != "" { |
| if info.AllowedHostname != "" { |
| return nil, fmt.Errorf("AllowedCN and AllowedHostname are mutually exclusive (cn=%q, hostname=%q)", info.AllowedCN, info.AllowedHostname) |
| } |
| verifyCertificate = func(cert *x509.Certificate) bool { |
| return info.AllowedCN == cert.Subject.CommonName |
| } |
| } |
| if info.AllowedHostname != "" { |
| verifyCertificate = func(cert *x509.Certificate) bool { |
| return cert.VerifyHostname(info.AllowedHostname) == nil |
| } |
| } |
| if verifyCertificate != nil { |
| cfg.VerifyPeerCertificate = func(rawCerts [][]byte, verifiedChains [][]*x509.Certificate) error { |
| for _, chains := range verifiedChains { |
| if len(chains) != 0 { |
| if verifyCertificate(chains[0]) { |
| return nil |
| } |
| } |
| } |
| return errors.New("client certificate authentication failed") |
| } |
| } |
| |
| // this only reloads certs when there's a client request |
| // TODO: support server-side refresh (e.g. inotify, SIGHUP), caching |
| cfg.GetCertificate = func(clientHello *tls.ClientHelloInfo) (cert *tls.Certificate, err error) { |
| cert, err = tlsutil.NewCert(info.CertFile, info.KeyFile, info.parseFunc) |
| if os.IsNotExist(err) { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "failed to find peer cert files", |
| zap.String("cert-file", info.CertFile), |
| zap.String("key-file", info.KeyFile), |
| zap.Error(err), |
| ) |
| } |
| } else if err != nil { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "failed to create peer certificate", |
| zap.String("cert-file", info.CertFile), |
| zap.String("key-file", info.KeyFile), |
| zap.Error(err), |
| ) |
| } |
| } |
| return cert, err |
| } |
| cfg.GetClientCertificate = func(unused *tls.CertificateRequestInfo) (cert *tls.Certificate, err error) { |
| cert, err = tlsutil.NewCert(info.CertFile, info.KeyFile, info.parseFunc) |
| if os.IsNotExist(err) { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "failed to find client cert files", |
| zap.String("cert-file", info.CertFile), |
| zap.String("key-file", info.KeyFile), |
| zap.Error(err), |
| ) |
| } |
| } else if err != nil { |
| if info.Logger != nil { |
| info.Logger.Warn( |
| "failed to create client certificate", |
| zap.String("cert-file", info.CertFile), |
| zap.String("key-file", info.KeyFile), |
| zap.Error(err), |
| ) |
| } |
| } |
| return cert, err |
| } |
| return cfg, nil |
| } |
| |
| // cafiles returns a list of CA file paths. |
| func (info TLSInfo) cafiles() []string { |
| cs := make([]string, 0) |
| if info.TrustedCAFile != "" { |
| cs = append(cs, info.TrustedCAFile) |
| } |
| return cs |
| } |
| |
| // ServerConfig generates a tls.Config object for use by an HTTP server. |
| func (info TLSInfo) ServerConfig() (*tls.Config, error) { |
| cfg, err := info.baseConfig() |
| if err != nil { |
| return nil, err |
| } |
| |
| cfg.ClientAuth = tls.NoClientCert |
| if info.TrustedCAFile != "" || info.ClientCertAuth { |
| cfg.ClientAuth = tls.RequireAndVerifyClientCert |
| } |
| |
| cs := info.cafiles() |
| if len(cs) > 0 { |
| cp, err := tlsutil.NewCertPool(cs) |
| if err != nil { |
| return nil, err |
| } |
| cfg.ClientCAs = cp |
| } |
| |
| // "h2" NextProtos is necessary for enabling HTTP2 for go's HTTP server |
| cfg.NextProtos = []string{"h2"} |
| |
| // go1.13 enables TLS 1.3 by default |
| // and in TLS 1.3, cipher suites are not configurable |
| // setting Max TLS version to TLS 1.2 for go 1.13 |
| cfg.MaxVersion = tls.VersionTLS12 |
| |
| return cfg, nil |
| } |
| |
| // ClientConfig generates a tls.Config object for use by an HTTP client. |
| func (info TLSInfo) ClientConfig() (*tls.Config, error) { |
| var cfg *tls.Config |
| var err error |
| |
| if !info.Empty() { |
| cfg, err = info.baseConfig() |
| if err != nil { |
| return nil, err |
| } |
| } else { |
| cfg = &tls.Config{ServerName: info.ServerName} |
| } |
| cfg.InsecureSkipVerify = info.InsecureSkipVerify |
| |
| cs := info.cafiles() |
| if len(cs) > 0 { |
| cfg.RootCAs, err = tlsutil.NewCertPool(cs) |
| if err != nil { |
| return nil, err |
| } |
| } |
| |
| if info.selfCert { |
| cfg.InsecureSkipVerify = true |
| } |
| |
| if info.EmptyCN { |
| hasNonEmptyCN := false |
| cn := "" |
| tlsutil.NewCert(info.CertFile, info.KeyFile, func(certPEMBlock []byte, keyPEMBlock []byte) (tls.Certificate, error) { |
| var block *pem.Block |
| block, _ = pem.Decode(certPEMBlock) |
| cert, err := x509.ParseCertificate(block.Bytes) |
| if err != nil { |
| return tls.Certificate{}, err |
| } |
| if len(cert.Subject.CommonName) != 0 { |
| hasNonEmptyCN = true |
| cn = cert.Subject.CommonName |
| } |
| return tls.X509KeyPair(certPEMBlock, keyPEMBlock) |
| }) |
| if hasNonEmptyCN { |
| return nil, fmt.Errorf("cert has non empty Common Name (%s)", cn) |
| } |
| } |
| |
| // go1.13 enables TLS 1.3 by default |
| // and in TLS 1.3, cipher suites are not configurable |
| // setting Max TLS version to TLS 1.2 for go 1.13 |
| cfg.MaxVersion = tls.VersionTLS12 |
| |
| return cfg, nil |
| } |
| |
| // IsClosedConnError returns true if the error is from closing listener, cmux. |
| // copied from golang.org/x/net/http2/http2.go |
| func IsClosedConnError(err error) bool { |
| // 'use of closed network connection' (Go <=1.8) |
| // 'use of closed file or network connection' (Go >1.8, internal/poll.ErrClosing) |
| // 'mux: listener closed' (cmux.ErrListenerClosed) |
| return err != nil && strings.Contains(err.Error(), "closed") |
| } |