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Diffstat (limited to 'src/crypto/tls/handshake_client.go')
-rw-r--r--src/crypto/tls/handshake_client.go638
1 files changed, 638 insertions, 0 deletions
diff --git a/src/crypto/tls/handshake_client.go b/src/crypto/tls/handshake_client.go
new file mode 100644
index 000000000..7f662e9c9
--- /dev/null
+++ b/src/crypto/tls/handshake_client.go
@@ -0,0 +1,638 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package tls
+
+import (
+ "bytes"
+ "crypto"
+ "crypto/ecdsa"
+ "crypto/rsa"
+ "crypto/subtle"
+ "crypto/x509"
+ "errors"
+ "fmt"
+ "io"
+ "net"
+ "strconv"
+)
+
+type clientHandshakeState struct {
+ c *Conn
+ serverHello *serverHelloMsg
+ hello *clientHelloMsg
+ suite *cipherSuite
+ finishedHash finishedHash
+ masterSecret []byte
+ session *ClientSessionState
+}
+
+func (c *Conn) clientHandshake() error {
+ if c.config == nil {
+ c.config = defaultConfig()
+ }
+
+ if len(c.config.ServerName) == 0 && !c.config.InsecureSkipVerify {
+ return errors.New("tls: either ServerName or InsecureSkipVerify must be specified in the tls.Config")
+ }
+
+ nextProtosLength := 0
+ for _, proto := range c.config.NextProtos {
+ if l := len(proto); l == 0 || l > 255 {
+ return errors.New("tls: invalid NextProtos value")
+ } else {
+ nextProtosLength += 1 + l
+ }
+ }
+ if nextProtosLength > 0xffff {
+ return errors.New("tls: NextProtos values too large")
+ }
+
+ hello := &clientHelloMsg{
+ vers: c.config.maxVersion(),
+ compressionMethods: []uint8{compressionNone},
+ random: make([]byte, 32),
+ ocspStapling: true,
+ serverName: c.config.ServerName,
+ supportedCurves: c.config.curvePreferences(),
+ supportedPoints: []uint8{pointFormatUncompressed},
+ nextProtoNeg: len(c.config.NextProtos) > 0,
+ secureRenegotiation: true,
+ alpnProtocols: c.config.NextProtos,
+ }
+
+ possibleCipherSuites := c.config.cipherSuites()
+ hello.cipherSuites = make([]uint16, 0, len(possibleCipherSuites))
+
+NextCipherSuite:
+ for _, suiteId := range possibleCipherSuites {
+ for _, suite := range cipherSuites {
+ if suite.id != suiteId {
+ continue
+ }
+ // Don't advertise TLS 1.2-only cipher suites unless
+ // we're attempting TLS 1.2.
+ if hello.vers < VersionTLS12 && suite.flags&suiteTLS12 != 0 {
+ continue
+ }
+ hello.cipherSuites = append(hello.cipherSuites, suiteId)
+ continue NextCipherSuite
+ }
+ }
+
+ _, err := io.ReadFull(c.config.rand(), hello.random)
+ if err != nil {
+ c.sendAlert(alertInternalError)
+ return errors.New("tls: short read from Rand: " + err.Error())
+ }
+
+ if hello.vers >= VersionTLS12 {
+ hello.signatureAndHashes = supportedSKXSignatureAlgorithms
+ }
+
+ var session *ClientSessionState
+ var cacheKey string
+ sessionCache := c.config.ClientSessionCache
+ if c.config.SessionTicketsDisabled {
+ sessionCache = nil
+ }
+
+ if sessionCache != nil {
+ hello.ticketSupported = true
+
+ // Try to resume a previously negotiated TLS session, if
+ // available.
+ cacheKey = clientSessionCacheKey(c.conn.RemoteAddr(), c.config)
+ candidateSession, ok := sessionCache.Get(cacheKey)
+ if ok {
+ // Check that the ciphersuite/version used for the
+ // previous session are still valid.
+ cipherSuiteOk := false
+ for _, id := range hello.cipherSuites {
+ if id == candidateSession.cipherSuite {
+ cipherSuiteOk = true
+ break
+ }
+ }
+
+ versOk := candidateSession.vers >= c.config.minVersion() &&
+ candidateSession.vers <= c.config.maxVersion()
+ if versOk && cipherSuiteOk {
+ session = candidateSession
+ }
+ }
+ }
+
+ if session != nil {
+ hello.sessionTicket = session.sessionTicket
+ // A random session ID is used to detect when the
+ // server accepted the ticket and is resuming a session
+ // (see RFC 5077).
+ hello.sessionId = make([]byte, 16)
+ if _, err := io.ReadFull(c.config.rand(), hello.sessionId); err != nil {
+ c.sendAlert(alertInternalError)
+ return errors.New("tls: short read from Rand: " + err.Error())
+ }
+ }
+
+ c.writeRecord(recordTypeHandshake, hello.marshal())
+
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+ serverHello, ok := msg.(*serverHelloMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(serverHello, msg)
+ }
+
+ vers, ok := c.config.mutualVersion(serverHello.vers)
+ if !ok || vers < VersionTLS10 {
+ // TLS 1.0 is the minimum version supported as a client.
+ c.sendAlert(alertProtocolVersion)
+ return fmt.Errorf("tls: server selected unsupported protocol version %x", serverHello.vers)
+ }
+ c.vers = vers
+ c.haveVers = true
+
+ suite := mutualCipherSuite(c.config.cipherSuites(), serverHello.cipherSuite)
+ if suite == nil {
+ c.sendAlert(alertHandshakeFailure)
+ return fmt.Errorf("tls: server selected an unsupported cipher suite")
+ }
+
+ hs := &clientHandshakeState{
+ c: c,
+ serverHello: serverHello,
+ hello: hello,
+ suite: suite,
+ finishedHash: newFinishedHash(c.vers),
+ session: session,
+ }
+
+ hs.finishedHash.Write(hs.hello.marshal())
+ hs.finishedHash.Write(hs.serverHello.marshal())
+
+ isResume, err := hs.processServerHello()
+ if err != nil {
+ return err
+ }
+
+ if isResume {
+ if err := hs.establishKeys(); err != nil {
+ return err
+ }
+ if err := hs.readSessionTicket(); err != nil {
+ return err
+ }
+ if err := hs.readFinished(c.firstFinished[:]); err != nil {
+ return err
+ }
+ if err := hs.sendFinished(nil); err != nil {
+ return err
+ }
+ } else {
+ if err := hs.doFullHandshake(); err != nil {
+ return err
+ }
+ if err := hs.establishKeys(); err != nil {
+ return err
+ }
+ if err := hs.sendFinished(c.firstFinished[:]); err != nil {
+ return err
+ }
+ if err := hs.readSessionTicket(); err != nil {
+ return err
+ }
+ if err := hs.readFinished(nil); err != nil {
+ return err
+ }
+ }
+
+ if sessionCache != nil && hs.session != nil && session != hs.session {
+ sessionCache.Put(cacheKey, hs.session)
+ }
+
+ c.didResume = isResume
+ c.handshakeComplete = true
+ c.cipherSuite = suite.id
+ return nil
+}
+
+func (hs *clientHandshakeState) doFullHandshake() error {
+ c := hs.c
+
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+ certMsg, ok := msg.(*certificateMsg)
+ if !ok || len(certMsg.certificates) == 0 {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(certMsg, msg)
+ }
+ hs.finishedHash.Write(certMsg.marshal())
+
+ certs := make([]*x509.Certificate, len(certMsg.certificates))
+ for i, asn1Data := range certMsg.certificates {
+ cert, err := x509.ParseCertificate(asn1Data)
+ if err != nil {
+ c.sendAlert(alertBadCertificate)
+ return errors.New("tls: failed to parse certificate from server: " + err.Error())
+ }
+ certs[i] = cert
+ }
+
+ if !c.config.InsecureSkipVerify {
+ opts := x509.VerifyOptions{
+ Roots: c.config.RootCAs,
+ CurrentTime: c.config.time(),
+ DNSName: c.config.ServerName,
+ Intermediates: x509.NewCertPool(),
+ }
+
+ for i, cert := range certs {
+ if i == 0 {
+ continue
+ }
+ opts.Intermediates.AddCert(cert)
+ }
+ c.verifiedChains, err = certs[0].Verify(opts)
+ if err != nil {
+ c.sendAlert(alertBadCertificate)
+ return err
+ }
+ }
+
+ switch certs[0].PublicKey.(type) {
+ case *rsa.PublicKey, *ecdsa.PublicKey:
+ break
+ default:
+ c.sendAlert(alertUnsupportedCertificate)
+ return fmt.Errorf("tls: server's certificate contains an unsupported type of public key: %T", certs[0].PublicKey)
+ }
+
+ c.peerCertificates = certs
+
+ if hs.serverHello.ocspStapling {
+ msg, err = c.readHandshake()
+ if err != nil {
+ return err
+ }
+ cs, ok := msg.(*certificateStatusMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(cs, msg)
+ }
+ hs.finishedHash.Write(cs.marshal())
+
+ if cs.statusType == statusTypeOCSP {
+ c.ocspResponse = cs.response
+ }
+ }
+
+ msg, err = c.readHandshake()
+ if err != nil {
+ return err
+ }
+
+ keyAgreement := hs.suite.ka(c.vers)
+
+ skx, ok := msg.(*serverKeyExchangeMsg)
+ if ok {
+ hs.finishedHash.Write(skx.marshal())
+ err = keyAgreement.processServerKeyExchange(c.config, hs.hello, hs.serverHello, certs[0], skx)
+ if err != nil {
+ c.sendAlert(alertUnexpectedMessage)
+ return err
+ }
+
+ msg, err = c.readHandshake()
+ if err != nil {
+ return err
+ }
+ }
+
+ var chainToSend *Certificate
+ var certRequested bool
+ certReq, ok := msg.(*certificateRequestMsg)
+ if ok {
+ certRequested = true
+
+ // RFC 4346 on the certificateAuthorities field:
+ // A list of the distinguished names of acceptable certificate
+ // authorities. These distinguished names may specify a desired
+ // distinguished name for a root CA or for a subordinate CA;
+ // thus, this message can be used to describe both known roots
+ // and a desired authorization space. If the
+ // certificate_authorities list is empty then the client MAY
+ // send any certificate of the appropriate
+ // ClientCertificateType, unless there is some external
+ // arrangement to the contrary.
+
+ hs.finishedHash.Write(certReq.marshal())
+
+ var rsaAvail, ecdsaAvail bool
+ for _, certType := range certReq.certificateTypes {
+ switch certType {
+ case certTypeRSASign:
+ rsaAvail = true
+ case certTypeECDSASign:
+ ecdsaAvail = true
+ }
+ }
+
+ // We need to search our list of client certs for one
+ // where SignatureAlgorithm is acceptable to the server and the
+ // Issuer is in certReq.certificateAuthorities
+ findCert:
+ for i, chain := range c.config.Certificates {
+ if !rsaAvail && !ecdsaAvail {
+ continue
+ }
+
+ for j, cert := range chain.Certificate {
+ x509Cert := chain.Leaf
+ // parse the certificate if this isn't the leaf
+ // node, or if chain.Leaf was nil
+ if j != 0 || x509Cert == nil {
+ if x509Cert, err = x509.ParseCertificate(cert); err != nil {
+ c.sendAlert(alertInternalError)
+ return errors.New("tls: failed to parse client certificate #" + strconv.Itoa(i) + ": " + err.Error())
+ }
+ }
+
+ switch {
+ case rsaAvail && x509Cert.PublicKeyAlgorithm == x509.RSA:
+ case ecdsaAvail && x509Cert.PublicKeyAlgorithm == x509.ECDSA:
+ default:
+ continue findCert
+ }
+
+ if len(certReq.certificateAuthorities) == 0 {
+ // they gave us an empty list, so just take the
+ // first cert from c.config.Certificates
+ chainToSend = &chain
+ break findCert
+ }
+
+ for _, ca := range certReq.certificateAuthorities {
+ if bytes.Equal(x509Cert.RawIssuer, ca) {
+ chainToSend = &chain
+ break findCert
+ }
+ }
+ }
+ }
+
+ msg, err = c.readHandshake()
+ if err != nil {
+ return err
+ }
+ }
+
+ shd, ok := msg.(*serverHelloDoneMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(shd, msg)
+ }
+ hs.finishedHash.Write(shd.marshal())
+
+ // If the server requested a certificate then we have to send a
+ // Certificate message, even if it's empty because we don't have a
+ // certificate to send.
+ if certRequested {
+ certMsg = new(certificateMsg)
+ if chainToSend != nil {
+ certMsg.certificates = chainToSend.Certificate
+ }
+ hs.finishedHash.Write(certMsg.marshal())
+ c.writeRecord(recordTypeHandshake, certMsg.marshal())
+ }
+
+ preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hs.hello, certs[0])
+ if err != nil {
+ c.sendAlert(alertInternalError)
+ return err
+ }
+ if ckx != nil {
+ hs.finishedHash.Write(ckx.marshal())
+ c.writeRecord(recordTypeHandshake, ckx.marshal())
+ }
+
+ if chainToSend != nil {
+ var signed []byte
+ certVerify := &certificateVerifyMsg{
+ hasSignatureAndHash: c.vers >= VersionTLS12,
+ }
+
+ key, ok := chainToSend.PrivateKey.(crypto.Signer)
+ if !ok {
+ c.sendAlert(alertInternalError)
+ return fmt.Errorf("tls: client certificate private key of type %T does not implement crypto.Signer", chainToSend.PrivateKey)
+ }
+ switch key.Public().(type) {
+ case *ecdsa.PublicKey:
+ digest, hashFunc, hashId := hs.finishedHash.hashForClientCertificate(signatureECDSA)
+ signed, err = key.Sign(c.config.rand(), digest, hashFunc)
+ certVerify.signatureAndHash.signature = signatureECDSA
+ certVerify.signatureAndHash.hash = hashId
+ case *rsa.PublicKey:
+ digest, hashFunc, hashId := hs.finishedHash.hashForClientCertificate(signatureRSA)
+ signed, err = key.Sign(c.config.rand(), digest, hashFunc)
+ certVerify.signatureAndHash.signature = signatureRSA
+ certVerify.signatureAndHash.hash = hashId
+ default:
+ err = fmt.Errorf("tls: unknown client certificate key type: %T", key)
+ }
+ if err != nil {
+ c.sendAlert(alertInternalError)
+ return errors.New("tls: failed to sign handshake with client certificate: " + err.Error())
+ }
+ certVerify.signature = signed
+
+ hs.finishedHash.Write(certVerify.marshal())
+ c.writeRecord(recordTypeHandshake, certVerify.marshal())
+ }
+
+ hs.masterSecret = masterFromPreMasterSecret(c.vers, preMasterSecret, hs.hello.random, hs.serverHello.random)
+ return nil
+}
+
+func (hs *clientHandshakeState) establishKeys() error {
+ c := hs.c
+
+ clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
+ keysFromMasterSecret(c.vers, hs.masterSecret, hs.hello.random, hs.serverHello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen)
+ var clientCipher, serverCipher interface{}
+ var clientHash, serverHash macFunction
+ if hs.suite.cipher != nil {
+ clientCipher = hs.suite.cipher(clientKey, clientIV, false /* not for reading */)
+ clientHash = hs.suite.mac(c.vers, clientMAC)
+ serverCipher = hs.suite.cipher(serverKey, serverIV, true /* for reading */)
+ serverHash = hs.suite.mac(c.vers, serverMAC)
+ } else {
+ clientCipher = hs.suite.aead(clientKey, clientIV)
+ serverCipher = hs.suite.aead(serverKey, serverIV)
+ }
+
+ c.in.prepareCipherSpec(c.vers, serverCipher, serverHash)
+ c.out.prepareCipherSpec(c.vers, clientCipher, clientHash)
+ return nil
+}
+
+func (hs *clientHandshakeState) serverResumedSession() bool {
+ // If the server responded with the same sessionId then it means the
+ // sessionTicket is being used to resume a TLS session.
+ return hs.session != nil && hs.hello.sessionId != nil &&
+ bytes.Equal(hs.serverHello.sessionId, hs.hello.sessionId)
+}
+
+func (hs *clientHandshakeState) processServerHello() (bool, error) {
+ c := hs.c
+
+ if hs.serverHello.compressionMethod != compressionNone {
+ c.sendAlert(alertUnexpectedMessage)
+ return false, errors.New("tls: server selected unsupported compression format")
+ }
+
+ clientDidNPN := hs.hello.nextProtoNeg
+ clientDidALPN := len(hs.hello.alpnProtocols) > 0
+ serverHasNPN := hs.serverHello.nextProtoNeg
+ serverHasALPN := len(hs.serverHello.alpnProtocol) > 0
+
+ if !clientDidNPN && serverHasNPN {
+ c.sendAlert(alertHandshakeFailure)
+ return false, errors.New("server advertised unrequested NPN extension")
+ }
+
+ if !clientDidALPN && serverHasALPN {
+ c.sendAlert(alertHandshakeFailure)
+ return false, errors.New("server advertised unrequested ALPN extension")
+ }
+
+ if serverHasNPN && serverHasALPN {
+ c.sendAlert(alertHandshakeFailure)
+ return false, errors.New("server advertised both NPN and ALPN extensions")
+ }
+
+ if serverHasALPN {
+ c.clientProtocol = hs.serverHello.alpnProtocol
+ c.clientProtocolFallback = false
+ }
+
+ if hs.serverResumedSession() {
+ // Restore masterSecret and peerCerts from previous state
+ hs.masterSecret = hs.session.masterSecret
+ c.peerCertificates = hs.session.serverCertificates
+ return true, nil
+ }
+ return false, nil
+}
+
+func (hs *clientHandshakeState) readFinished(out []byte) error {
+ c := hs.c
+
+ c.readRecord(recordTypeChangeCipherSpec)
+ if err := c.in.error(); err != nil {
+ return err
+ }
+
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+ serverFinished, ok := msg.(*finishedMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(serverFinished, msg)
+ }
+
+ verify := hs.finishedHash.serverSum(hs.masterSecret)
+ if len(verify) != len(serverFinished.verifyData) ||
+ subtle.ConstantTimeCompare(verify, serverFinished.verifyData) != 1 {
+ c.sendAlert(alertHandshakeFailure)
+ return errors.New("tls: server's Finished message was incorrect")
+ }
+ hs.finishedHash.Write(serverFinished.marshal())
+ copy(out, verify)
+ return nil
+}
+
+func (hs *clientHandshakeState) readSessionTicket() error {
+ if !hs.serverHello.ticketSupported {
+ return nil
+ }
+
+ c := hs.c
+ msg, err := c.readHandshake()
+ if err != nil {
+ return err
+ }
+ sessionTicketMsg, ok := msg.(*newSessionTicketMsg)
+ if !ok {
+ c.sendAlert(alertUnexpectedMessage)
+ return unexpectedMessageError(sessionTicketMsg, msg)
+ }
+ hs.finishedHash.Write(sessionTicketMsg.marshal())
+
+ hs.session = &ClientSessionState{
+ sessionTicket: sessionTicketMsg.ticket,
+ vers: c.vers,
+ cipherSuite: hs.suite.id,
+ masterSecret: hs.masterSecret,
+ serverCertificates: c.peerCertificates,
+ }
+
+ return nil
+}
+
+func (hs *clientHandshakeState) sendFinished(out []byte) error {
+ c := hs.c
+
+ c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
+ if hs.serverHello.nextProtoNeg {
+ nextProto := new(nextProtoMsg)
+ proto, fallback := mutualProtocol(c.config.NextProtos, hs.serverHello.nextProtos)
+ nextProto.proto = proto
+ c.clientProtocol = proto
+ c.clientProtocolFallback = fallback
+
+ hs.finishedHash.Write(nextProto.marshal())
+ c.writeRecord(recordTypeHandshake, nextProto.marshal())
+ }
+
+ finished := new(finishedMsg)
+ finished.verifyData = hs.finishedHash.clientSum(hs.masterSecret)
+ hs.finishedHash.Write(finished.marshal())
+ c.writeRecord(recordTypeHandshake, finished.marshal())
+ copy(out, finished.verifyData)
+ return nil
+}
+
+// clientSessionCacheKey returns a key used to cache sessionTickets that could
+// be used to resume previously negotiated TLS sessions with a server.
+func clientSessionCacheKey(serverAddr net.Addr, config *Config) string {
+ if len(config.ServerName) > 0 {
+ return config.ServerName
+ }
+ return serverAddr.String()
+}
+
+// mutualProtocol finds the mutual Next Protocol Negotiation or ALPN protocol
+// given list of possible protocols and a list of the preference order. The
+// first list must not be empty. It returns the resulting protocol and flag
+// indicating if the fallback case was reached.
+func mutualProtocol(protos, preferenceProtos []string) (string, bool) {
+ for _, s := range preferenceProtos {
+ for _, c := range protos {
+ if s == c {
+ return s, false
+ }
+ }
+ }
+
+ return protos[0], true
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-18 10:25:09 +0000