- // 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 main
-
- import (
- "bytes"
- "crypto/ecdsa"
- "crypto/elliptic"
- "crypto/rsa"
- "crypto/subtle"
- "crypto/x509"
- "encoding/asn1"
- "errors"
- "fmt"
- "io"
- "math/big"
- "net"
- "strconv"
- )
-
- type clientHandshakeState struct {
- c *Conn
- serverHello *serverHelloMsg
- hello *clientHelloMsg
- suite *cipherSuite
- finishedHash finishedHash
- masterSecret []byte
- session *ClientSessionState
- finishedBytes []byte
- }
-
- 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")
- }
-
- c.sendHandshakeSeq = 0
- c.recvHandshakeSeq = 0
-
- nextProtosLength := 0
- for _, proto := range c.config.NextProtos {
- if l := len(proto); 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{
- isDTLS: c.isDTLS,
- 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: []byte{},
- alpnProtocols: c.config.NextProtos,
- duplicateExtension: c.config.Bugs.DuplicateExtension,
- channelIDSupported: c.config.ChannelID != nil,
- npnLast: c.config.Bugs.SwapNPNAndALPN,
- extendedMasterSecret: c.config.maxVersion() >= VersionTLS10,
- srtpProtectionProfiles: c.config.SRTPProtectionProfiles,
- srtpMasterKeyIdentifier: c.config.Bugs.SRTPMasterKeyIdentifer,
- customExtension: c.config.Bugs.CustomExtension,
- }
-
- if c.config.Bugs.SendClientVersion != 0 {
- hello.vers = c.config.Bugs.SendClientVersion
- }
-
- if c.config.Bugs.NoExtendedMasterSecret {
- hello.extendedMasterSecret = false
- }
-
- if c.config.Bugs.NoSupportedCurves {
- hello.supportedCurves = nil
- }
-
- if len(c.clientVerify) > 0 && !c.config.Bugs.EmptyRenegotiationInfo {
- if c.config.Bugs.BadRenegotiationInfo {
- hello.secureRenegotiation = append(hello.secureRenegotiation, c.clientVerify...)
- hello.secureRenegotiation[0] ^= 0x80
- } else {
- hello.secureRenegotiation = c.clientVerify
- }
- }
-
- if c.config.Bugs.NoRenegotiationInfo {
- hello.secureRenegotiation = nil
- }
-
- 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
- }
- // Don't advertise non-DTLS cipher suites on DTLS.
- if c.isDTLS && suite.flags&suiteNoDTLS != 0 && !c.config.Bugs.EnableAllCiphersInDTLS {
- continue
- }
- hello.cipherSuites = append(hello.cipherSuites, suiteId)
- continue NextCipherSuite
- }
- }
-
- if c.config.Bugs.SendRenegotiationSCSV {
- hello.cipherSuites = append(hello.cipherSuites, renegotiationSCSV)
- }
-
- if c.config.Bugs.SendFallbackSCSV {
- hello.cipherSuites = append(hello.cipherSuites, fallbackSCSV)
- }
-
- _, 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 && !c.config.Bugs.NoSignatureAndHashes {
- hello.signatureAndHashes = c.config.signatureAndHashesForClient()
- }
-
- var session *ClientSessionState
- var cacheKey string
- sessionCache := c.config.ClientSessionCache
-
- if sessionCache != nil {
- hello.ticketSupported = !c.config.SessionTicketsDisabled
-
- // Try to resume a previously negotiated TLS session, if
- // available.
- cacheKey = clientSessionCacheKey(c.conn.RemoteAddr(), c.config)
- candidateSession, ok := sessionCache.Get(cacheKey)
- if ok {
- ticketOk := !c.config.SessionTicketsDisabled || candidateSession.sessionTicket == nil
-
- // 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 ticketOk && versOk && cipherSuiteOk {
- session = candidateSession
- }
- }
- }
-
- if session != nil {
- if session.sessionTicket != nil {
- hello.sessionTicket = session.sessionTicket
- if c.config.Bugs.CorruptTicket {
- hello.sessionTicket = make([]byte, len(session.sessionTicket))
- copy(hello.sessionTicket, session.sessionTicket)
- if len(hello.sessionTicket) > 0 {
- offset := 40
- if offset > len(hello.sessionTicket) {
- offset = len(hello.sessionTicket) - 1
- }
- hello.sessionTicket[offset] ^= 0x40
- }
- }
- // A random session ID is used to detect when the
- // server accepted the ticket and is resuming a session
- // (see RFC 5077).
- sessionIdLen := 16
- if c.config.Bugs.OversizedSessionId {
- sessionIdLen = 33
- }
- hello.sessionId = make([]byte, sessionIdLen)
- if _, err := io.ReadFull(c.config.rand(), hello.sessionId); err != nil {
- c.sendAlert(alertInternalError)
- return errors.New("tls: short read from Rand: " + err.Error())
- }
- } else {
- hello.sessionId = session.sessionId
- }
- }
-
- var helloBytes []byte
- if c.config.Bugs.SendV2ClientHello {
- // Test that the peer left-pads random.
- hello.random[0] = 0
- v2Hello := &v2ClientHelloMsg{
- vers: hello.vers,
- cipherSuites: hello.cipherSuites,
- // No session resumption for V2ClientHello.
- sessionId: nil,
- challenge: hello.random[1:],
- }
- helloBytes = v2Hello.marshal()
- c.writeV2Record(helloBytes)
- } else {
- helloBytes = hello.marshal()
- c.writeRecord(recordTypeHandshake, helloBytes)
- }
- c.dtlsFlushHandshake()
-
- if err := c.simulatePacketLoss(nil); err != nil {
- return err
- }
- msg, err := c.readHandshake()
- if err != nil {
- return err
- }
-
- if c.isDTLS {
- helloVerifyRequest, ok := msg.(*helloVerifyRequestMsg)
- if ok {
- if helloVerifyRequest.vers != VersionTLS10 {
- // Per RFC 6347, the version field in
- // HelloVerifyRequest SHOULD be always DTLS
- // 1.0. Enforce this for testing purposes.
- return errors.New("dtls: bad HelloVerifyRequest version")
- }
-
- hello.raw = nil
- hello.cookie = helloVerifyRequest.cookie
- helloBytes = hello.marshal()
- c.writeRecord(recordTypeHandshake, helloBytes)
- c.dtlsFlushHandshake()
-
- if err := c.simulatePacketLoss(nil); err != nil {
- return err
- }
- msg, err = c.readHandshake()
- if err != nil {
- return err
- }
- }
- }
-
- serverHello, ok := msg.(*serverHelloMsg)
- if !ok {
- c.sendAlert(alertUnexpectedMessage)
- return unexpectedMessageError(serverHello, msg)
- }
-
- c.vers, ok = c.config.mutualVersion(serverHello.vers)
- if !ok {
- c.sendAlert(alertProtocolVersion)
- return fmt.Errorf("tls: server selected unsupported protocol version %x", serverHello.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")
- }
-
- if c.config.Bugs.RequireRenegotiationInfo && serverHello.secureRenegotiation == nil {
- return errors.New("tls: renegotiation extension missing")
- }
-
- if len(c.clientVerify) > 0 && !c.config.Bugs.NoRenegotiationInfo {
- var expectedRenegInfo []byte
- expectedRenegInfo = append(expectedRenegInfo, c.clientVerify...)
- expectedRenegInfo = append(expectedRenegInfo, c.serverVerify...)
- if !bytes.Equal(serverHello.secureRenegotiation, expectedRenegInfo) {
- c.sendAlert(alertHandshakeFailure)
- return fmt.Errorf("tls: renegotiation mismatch")
- }
- }
-
- if expected := c.config.Bugs.ExpectedCustomExtension; expected != nil {
- if serverHello.customExtension != *expected {
- return fmt.Errorf("tls: bad custom extension contents %q", serverHello.customExtension)
- }
- }
-
- hs := &clientHandshakeState{
- c: c,
- serverHello: serverHello,
- hello: hello,
- suite: suite,
- finishedHash: newFinishedHash(c.vers, suite),
- session: session,
- }
-
- hs.writeHash(helloBytes, hs.c.sendHandshakeSeq-1)
- hs.writeServerHash(hs.serverHello.marshal())
-
- if c.config.Bugs.EarlyChangeCipherSpec > 0 {
- hs.establishKeys()
- c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
- }
-
- isResume, err := hs.processServerHello()
- if err != nil {
- return err
- }
-
- if isResume {
- if c.config.Bugs.EarlyChangeCipherSpec == 0 {
- 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, isResume); 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[:], isResume); err != nil {
- return err
- }
- // Most retransmits are triggered by a timeout, but the final
- // leg of the handshake is retransmited upon re-receiving a
- // Finished.
- if err := c.simulatePacketLoss(func() {
- c.writeRecord(recordTypeHandshake, hs.finishedBytes)
- c.dtlsFlushHandshake()
- }); 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
- copy(c.clientRandom[:], hs.hello.random)
- copy(c.serverRandom[:], hs.serverHello.random)
- copy(c.masterSecret[:], hs.masterSecret)
- return nil
- }
-
- func (hs *clientHandshakeState) doFullHandshake() error {
- c := hs.c
-
- var leaf *x509.Certificate
- if hs.suite.flags&suitePSK == 0 {
- 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.writeServerHash(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
- }
- leaf = certs[0]
-
- 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 = leaf.Verify(opts)
- if err != nil {
- c.sendAlert(alertBadCertificate)
- return err
- }
- }
-
- switch leaf.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", leaf.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.writeServerHash(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.writeServerHash(skx.marshal())
- err = keyAgreement.processServerKeyExchange(c.config, hs.hello, hs.serverHello, leaf, 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.writeServerHash(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 RSA 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 RSA 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.writeServerHash(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.writeClientHash(certMsg.marshal())
- c.writeRecord(recordTypeHandshake, certMsg.marshal())
- }
-
- preMasterSecret, ckx, err := keyAgreement.generateClientKeyExchange(c.config, hs.hello, leaf)
- if err != nil {
- c.sendAlert(alertInternalError)
- return err
- }
- if ckx != nil {
- if c.config.Bugs.EarlyChangeCipherSpec < 2 {
- hs.writeClientHash(ckx.marshal())
- }
- c.writeRecord(recordTypeHandshake, ckx.marshal())
- }
-
- if hs.serverHello.extendedMasterSecret && c.vers >= VersionTLS10 {
- hs.masterSecret = extendedMasterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret, hs.finishedHash)
- c.extendedMasterSecret = true
- } else {
- if c.config.Bugs.RequireExtendedMasterSecret {
- return errors.New("tls: extended master secret required but not supported by peer")
- }
- hs.masterSecret = masterFromPreMasterSecret(c.vers, hs.suite, preMasterSecret, hs.hello.random, hs.serverHello.random)
- }
-
- if chainToSend != nil {
- var signed []byte
- certVerify := &certificateVerifyMsg{
- hasSignatureAndHash: c.vers >= VersionTLS12,
- }
-
- // Determine the hash to sign.
- var signatureType uint8
- switch c.config.Certificates[0].PrivateKey.(type) {
- case *ecdsa.PrivateKey:
- signatureType = signatureECDSA
- case *rsa.PrivateKey:
- signatureType = signatureRSA
- default:
- c.sendAlert(alertInternalError)
- return errors.New("unknown private key type")
- }
- if c.config.Bugs.IgnorePeerSignatureAlgorithmPreferences {
- certReq.signatureAndHashes = c.config.signatureAndHashesForClient()
- }
- certVerify.signatureAndHash, err = hs.finishedHash.selectClientCertSignatureAlgorithm(certReq.signatureAndHashes, c.config.signatureAndHashesForClient(), signatureType)
- if err != nil {
- c.sendAlert(alertInternalError)
- return err
- }
- digest, hashFunc, err := hs.finishedHash.hashForClientCertificate(certVerify.signatureAndHash, hs.masterSecret)
- if err != nil {
- c.sendAlert(alertInternalError)
- return err
- }
- if c.config.Bugs.InvalidCertVerifySignature {
- digest[0] ^= 0x80
- }
-
- switch key := c.config.Certificates[0].PrivateKey.(type) {
- case *ecdsa.PrivateKey:
- var r, s *big.Int
- r, s, err = ecdsa.Sign(c.config.rand(), key, digest)
- if err == nil {
- signed, err = asn1.Marshal(ecdsaSignature{r, s})
- }
- case *rsa.PrivateKey:
- signed, err = rsa.SignPKCS1v15(c.config.rand(), key, hashFunc, digest)
- default:
- err = errors.New("unknown private key type")
- }
- if err != nil {
- c.sendAlert(alertInternalError)
- return errors.New("tls: failed to sign handshake with client certificate: " + err.Error())
- }
- certVerify.signature = signed
-
- hs.writeClientHash(certVerify.marshal())
- c.writeRecord(recordTypeHandshake, certVerify.marshal())
- }
- c.dtlsFlushHandshake()
-
- hs.finishedHash.discardHandshakeBuffer()
-
- return nil
- }
-
- func (hs *clientHandshakeState) establishKeys() error {
- c := hs.c
-
- clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
- keysFromMasterSecret(c.vers, hs.suite, 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
- c.usedALPN = true
- }
-
- if !hs.hello.channelIDSupported && hs.serverHello.channelIDRequested {
- c.sendAlert(alertHandshakeFailure)
- return false, errors.New("server advertised unrequested Channel ID extension")
- }
-
- if hs.serverHello.srtpProtectionProfile != 0 {
- if hs.serverHello.srtpMasterKeyIdentifier != "" {
- return false, errors.New("tls: server selected SRTP MKI value")
- }
-
- found := false
- for _, p := range c.config.SRTPProtectionProfiles {
- if p == hs.serverHello.srtpProtectionProfile {
- found = true
- break
- }
- }
- if !found {
- return false, errors.New("tls: server advertised unsupported SRTP profile")
- }
-
- c.srtpProtectionProfile = hs.serverHello.srtpProtectionProfile
- }
-
- if hs.serverResumedSession() {
- // For test purposes, assert that the server never accepts the
- // resumption offer on renegotiation.
- if c.cipherSuite != nil && c.config.Bugs.FailIfResumeOnRenego {
- return false, errors.New("tls: server resumed session on renegotiation")
- }
-
- // Restore masterSecret and peerCerts from previous state
- hs.masterSecret = hs.session.masterSecret
- c.peerCertificates = hs.session.serverCertificates
- c.extendedMasterSecret = hs.session.extendedMasterSecret
- hs.finishedHash.discardHandshakeBuffer()
- 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)
- }
-
- if c.config.Bugs.EarlyChangeCipherSpec == 0 {
- 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")
- }
- }
- c.serverVerify = append(c.serverVerify[:0], serverFinished.verifyData...)
- copy(out, serverFinished.verifyData)
- hs.writeServerHash(serverFinished.marshal())
- return nil
- }
-
- func (hs *clientHandshakeState) readSessionTicket() error {
- c := hs.c
-
- // Create a session with no server identifier. Either a
- // session ID or session ticket will be attached.
- session := &ClientSessionState{
- vers: c.vers,
- cipherSuite: hs.suite.id,
- masterSecret: hs.masterSecret,
- handshakeHash: hs.finishedHash.server.Sum(nil),
- serverCertificates: c.peerCertificates,
- }
-
- if !hs.serverHello.ticketSupported {
- if c.config.Bugs.ExpectNewTicket {
- return errors.New("tls: expected new ticket")
- }
- if hs.session == nil && len(hs.serverHello.sessionId) > 0 {
- session.sessionId = hs.serverHello.sessionId
- hs.session = session
- }
- return nil
- }
-
- msg, err := c.readHandshake()
- if err != nil {
- return err
- }
- sessionTicketMsg, ok := msg.(*newSessionTicketMsg)
- if !ok {
- c.sendAlert(alertUnexpectedMessage)
- return unexpectedMessageError(sessionTicketMsg, msg)
- }
-
- session.sessionTicket = sessionTicketMsg.ticket
- hs.session = session
-
- hs.writeServerHash(sessionTicketMsg.marshal())
-
- return nil
- }
-
- func (hs *clientHandshakeState) sendFinished(out []byte, isResume bool) error {
- c := hs.c
-
- var postCCSBytes []byte
- seqno := hs.c.sendHandshakeSeq
- 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
-
- nextProtoBytes := nextProto.marshal()
- hs.writeHash(nextProtoBytes, seqno)
- seqno++
- postCCSBytes = append(postCCSBytes, nextProtoBytes...)
- }
-
- if hs.serverHello.channelIDRequested {
- encryptedExtensions := new(encryptedExtensionsMsg)
- if c.config.ChannelID.Curve != elliptic.P256() {
- return fmt.Errorf("tls: Channel ID is not on P-256.")
- }
- var resumeHash []byte
- if isResume {
- resumeHash = hs.session.handshakeHash
- }
- r, s, err := ecdsa.Sign(c.config.rand(), c.config.ChannelID, hs.finishedHash.hashForChannelID(resumeHash))
- if err != nil {
- return err
- }
- channelID := make([]byte, 128)
- writeIntPadded(channelID[0:32], c.config.ChannelID.X)
- writeIntPadded(channelID[32:64], c.config.ChannelID.Y)
- writeIntPadded(channelID[64:96], r)
- writeIntPadded(channelID[96:128], s)
- encryptedExtensions.channelID = channelID
-
- c.channelID = &c.config.ChannelID.PublicKey
-
- encryptedExtensionsBytes := encryptedExtensions.marshal()
- hs.writeHash(encryptedExtensionsBytes, seqno)
- seqno++
- postCCSBytes = append(postCCSBytes, encryptedExtensionsBytes...)
- }
-
- finished := new(finishedMsg)
- if c.config.Bugs.EarlyChangeCipherSpec == 2 {
- finished.verifyData = hs.finishedHash.clientSum(nil)
- } else {
- finished.verifyData = hs.finishedHash.clientSum(hs.masterSecret)
- }
- copy(out, finished.verifyData)
- if c.config.Bugs.BadFinished {
- finished.verifyData[0]++
- }
- c.clientVerify = append(c.clientVerify[:0], finished.verifyData...)
- hs.finishedBytes = finished.marshal()
- hs.writeHash(hs.finishedBytes, seqno)
- postCCSBytes = append(postCCSBytes, hs.finishedBytes...)
-
- if c.config.Bugs.FragmentAcrossChangeCipherSpec {
- c.writeRecord(recordTypeHandshake, postCCSBytes[:5])
- postCCSBytes = postCCSBytes[5:]
- }
- c.dtlsFlushHandshake()
-
- if !c.config.Bugs.SkipChangeCipherSpec &&
- c.config.Bugs.EarlyChangeCipherSpec == 0 {
- c.writeRecord(recordTypeChangeCipherSpec, []byte{1})
- }
-
- if c.config.Bugs.AppDataAfterChangeCipherSpec != nil {
- c.writeRecord(recordTypeApplicationData, c.config.Bugs.AppDataAfterChangeCipherSpec)
- }
- if c.config.Bugs.AlertAfterChangeCipherSpec != 0 {
- c.sendAlert(c.config.Bugs.AlertAfterChangeCipherSpec)
- return errors.New("tls: simulating post-CCS alert")
- }
-
- if !c.config.Bugs.SkipFinished {
- c.writeRecord(recordTypeHandshake, postCCSBytes)
- c.dtlsFlushHandshake()
- }
- return nil
- }
-
- func (hs *clientHandshakeState) writeClientHash(msg []byte) {
- // writeClientHash is called before writeRecord.
- hs.writeHash(msg, hs.c.sendHandshakeSeq)
- }
-
- func (hs *clientHandshakeState) writeServerHash(msg []byte) {
- // writeServerHash is called after readHandshake.
- hs.writeHash(msg, hs.c.recvHandshakeSeq-1)
- }
-
- func (hs *clientHandshakeState) writeHash(msg []byte, seqno uint16) {
- if hs.c.isDTLS {
- // This is somewhat hacky. DTLS hashes a slightly different format.
- // First, the TLS header.
- hs.finishedHash.Write(msg[:4])
- // Then the sequence number and reassembled fragment offset (always 0).
- hs.finishedHash.Write([]byte{byte(seqno >> 8), byte(seqno), 0, 0, 0})
- // Then the reassembled fragment (always equal to the message length).
- hs.finishedHash.Write(msg[1:4])
- // And then the message body.
- hs.finishedHash.Write(msg[4:])
- } else {
- hs.finishedHash.Write(msg)
- }
- }
-
- // 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
- }
-
- // writeIntPadded writes x into b, padded up with leading zeros as
- // needed.
- func writeIntPadded(b []byte, x *big.Int) {
- for i := range b {
- b[i] = 0
- }
- xb := x.Bytes()
- copy(b[len(b)-len(xb):], xb)
- }
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